KR102747128B1 - Napped artificial leather and composite material - Google Patents

Abstract

A napped artificial leather having a thickness of 0.25 to 1.5 mm, comprising a fiber entanglement body including ultrafine fibers having a fineness of 0.5 dtex or less, and a polymer elastomer such as polyurethane impregnated into the fiber entanglement body, the artificial leather having a main surface being a napped surface on which ultrafine fibers are napped. In addition, the artificial leather includes phosphorus-based flame retardant particles attached to the polymer elastomer such as polyurethane, which are distributed in a range of 200 ㎛ or less in a thickness from the back surface with respect to the main surface. In addition, the phosphorus-based flame retardant particles have an average particle diameter of 0.1 to 30 ㎛, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point, or when the melting point does not exist, a decomposition temperature of 150°C or more, and a content ratio of the phosphorus-based flame retardant particles is 1 to 6 mass% in terms of a phosphorus atom content ratio.

Description

NAPPED ARTIFICIAL LEATHER AND COMPOSITE MATERIAL

The present invention relates to a pile artificial leather having both flame retardancy and excellent surface luxuriousness, and a composite material using the same.

Conventionally, a napped artificial leather having an appearance similar to suede leather has been known, which is obtained by raising one side of an artificial leather material by impregnating a polymer elastic material into a fiber entanglement such as a nonwoven fabric. Napped artificial leather is used as a material for shoes, clothing, gloves, bags, balls, etc., and as an interior material for buildings and vehicles. Napped artificial leather has the advantages of superior quality stability, heat resistance, water resistance, and wear resistance, and is easy to care for, compared to natural leather such as suede leather.

Recently, however, leather-like sheets such as artificial leather have been adopted as interior materials for public transport such as aircraft, ships, and railway vehicles, and for interior materials for public buildings such as hotels and department stores. In order to ensure safety in the event of a fire, interior materials used in public places require a high level of flame retardancy such as self-extinguishing properties, low smoke properties, and low heat generation. In order to clear such flame retardancy requirements, it has been widely practiced to blend halogen-based flame retardants with high flame retardancy performance into interior materials. However, since halogen-based flame retardants generate toxic halogen gases when burned, it is recommended by public organizations and users concerned about the environment not to use halogen-based flame retardants. For example, the following Patent Documents 1 to 4 disclose a technology for using a phosphorus-based flame retardant or a metal hydroxide-based flame retardant to flame retardant leather-like sheets.

Japanese Patent Publication No. 56-050985 Japanese Patent Publication No. 2009-235628 Japanese Patent Publication No. 2013-227685 Japanese Patent Publication No. 2007-321280

The napped artificial leather obtained by impregnating a polymer elastic material into the internal pores of a fiber entanglement of ultrafine fibers having a fineness of less than 1 dtex has a smooth surface touch and superior luxuriousness compared to napped artificial leather made of a knitted fabric of fibers having a fineness of about 1 to 5 dtex, also called regular fibers. However, napped artificial leather containing ultrafine fibers has lower flame retardancy than napped artificial leather containing regular fibers because the surface area of the fibers is larger.

In addition, it was difficult to provide sufficient flame retardancy to the artificial leather containing ultrafine fibers without using a halogen-based flame retardant. Non-halogen-based flame retardants that do not contain halogen include phosphorus-based flame retardants. Specific examples of the phosphorus-based flame retardants include, for example, inorganic polyphosphate salts such as metal polyphosphate, ammonium polyphosphate, and polycarbamate polyphosphate, and phosphates such as guanidine phosphate. However, since inorganic polyphosphate salts and phosphates have relatively high water solubility, they tend to swell or dissolve due to moisture, water, or heat in the usage environment, or to bleed to the surface of the artificial leather when heat is applied due to drying treatment after being applied to the artificial leather. When the flame retardant swells or dissolves or bleeds to the surface of the artificial leather, the primary surface, which is the grain surface, is whitened or colored by the flame retardant, and in some cases, the luxurious feel of the surface of the artificial leather is impaired. In addition, aliphatic phosphate esters such as aromatic-containing phosphate esters, aliphatic phosphonic acid esters, and aliphatic cyclic phosphonic acid esters have relatively low water solubility, but have insufficient flame retardancy effects, impair the texture of raised artificial leather, and are prone to causing bleeding, etc.

The present invention aims to provide a napped artificial leather including a fiber entanglement of ultrafine fibers, which does not impair the luxurious feel of the surface and is flame-retardant-imparted by using a non-halogen flame retardant, and a composite material using the same.

One aspect of the present invention is a napped artificial leather having a thickness of 0.25 to 1.5 mm, which comprises a fiber entanglement body including ultrafine fibers having a fineness of 0.5 dtex or less, and a polymer elastomer impregnated into the fiber entanglement body, and which has a main surface as a napped surface on which ultrafine fibers are napped. The artificial leather further comprises phosphorus flame retardant particles attached to the polymer elastomer body, which are distributed in a range of a thickness of 200 ㎛ or less from the back surface of the main surface.

The phosphorus flame retardant particles have an average particle size of 0.1 to 30 ㎛, preferably 0.5 to 30 ㎛, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point, or, when no melting point exists, a decomposition temperature of 150°C or more. In addition, the content ratio of the phosphorus flame retardant particles in the raised artificial leather is 1 to 6 mass% in terms of the content ratio converted to phosphorus atoms.

According to such a raised artificial leather, by distributing the phosphorus flame retardant particles at a high concentration on the back side, which is the opposite side to the main side forming the appearance of the raised artificial leather, in the raised artificial leather including a fiber entanglement of ultrafine fibers, a raised artificial leather is obtained that is flame retardant-improved using a non-halogen flame retardant without impairing the luxurious feel of the surface.

The polymer elastomer preferably includes a polyurethane which is a reaction product of a polyurethane raw material including a polymer polyol, an organic polyisocyanate, and a chain extender, wherein the polymer polyol is a polycarbonate polyol at 60 mass% or more and has an average repeating carbon number excluding a reactive functional group of 6.5 or less, and the organic polyisocyanate preferably includes at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate.

In addition, it is desirable that the artificial leather with raised edges have a surface weight of 100 to 300 g/㎡.

As the phosphorus flame retardant particles, organic phosphinic acid metal salts, aromatic phosphonic acid esters, and phosphoric acid ester amides are particularly preferable. In addition, as the phosphorus flame retardant particles, those containing at least one selected from dialkylphosphinic acid metal salts and monoalkylphosphinic acid metal salts are particularly preferable because they have high water resistance and heat resistance, a high phosphorus atom content, and a high flame retardant effect.

In addition, it is preferable that the artificial leather with raised hair has 90 to 100 mass% of the phosphorus flame retardant particles present in a range of 200 ㎛ or less in thickness from the back of the artificial leather with raised hair, since this does not impair the luxurious feel of the surface.

In addition, it is preferable that the content ratio of phosphorus flame retardant particles in the total amount of phosphorus flame retardant particles and polymer elastomer is 5 to 20 mass% in terms of phosphorus atoms in the artificial leather, since this can sufficiently suppress the reduction in flame retardancy due to the polymer elastomer.

In addition, the artificial leather with a raised surface comprises a first polymer elastomer in which the polymer elastomer exists over the entire thickness cross-section, and a second polymer elastomer distributed in a range of a thickness of 200 ㎛ or less from the back surface of the artificial leather with a raised surface, and the phosphorus flame retardant particles are preferably attached to the second polymer elastomer, since it is easy to distribute the phosphorus flame retardant particles in a range of a thickness of 200 ㎛ or less.

In addition, it is preferable that the content ratio of phosphorus flame retardant particles in the total amount of phosphorus flame retardant particles and the second polymer elastomer is 10 to 30 mass% in terms of phosphorus atoms, since the influence of the second polymer elastomer on the reduction in flame retardancy is small.

In addition, another aspect of the present invention is a composite material formed by bonding an interior material to the back surface of any of the above-mentioned artificial leathers with an adhesive. Such a composite material is an interior or exterior material having a surface decorated with artificial leathers, and has flame retardancy and excellent surface quality.

For example, the composite material described above can realize a total heat generation (THR) of 10 MJ/㎡ or less, a maximum heat generation rate (PHRR) of 250 kW/㎡ or less, or a maximum average rate of heat dissipation (MARHE) of 90 kW/㎡ or less.

According to the present invention, in a napped artificial leather including a fiber entanglement of ultrafine fibers, a napped artificial leather imparted with flame retardancy by using a non-halogen flame retardant without impairing the luxurious feel of the surface and a composite material using the same are obtained.

The napped artificial leather of the present embodiment is a napped artificial leather having a thickness of 0.25 to 1.5 mm, which comprises a fiber entanglement body including ultrafine fibers having a fineness of 0.5 dtex or less, and a polymer elastomer impregnated into the fiber entanglement body, and which has a main surface as a napped surface on which ultrafine fibers are napped. In addition, the napped artificial leather comprises phosphorus flame retardant particles attached to the polymer elastomer, which are distributed in a range of 200 ㎛ or less in thickness from the back surface of the main surface.

Polymer elastomers provide dimensional stability to fiber entanglements or provide a luxurious feel to the surface of the fabric. Polymer elastomers include polyurethane, acrylonitrile elastomer, olefin elastomer, polyester elastomer, polyamide elastomer, and acrylic elastomer. These may be used alone or in combination of two or more. Among these, polyurethane is preferable.

As the polymer elastomer, it is particularly preferable to include a polyurethane which is a reaction product of a polyurethane raw material including a polymer polyol, an organic polyisocyanate, and a chain extender, wherein the polymer polyol is a polycarbonate polyol at 60 mass% or more and has an average repeating carbon number excluding a reactive functional group of 6.5 or less, and the organic polyisocyanate includes at least one selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate.

In addition, the phosphorus flame retardant particles have an average particle size of 0.1 to 30 ㎛, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point, or, if no melting point exists, a decomposition temperature of 150°C or more. In addition, the pile artificial leather contains 1 to 6 mass% of phosphorus flame retardant particles in terms of phosphorus atom content.

A raised artificial leather is, for example, a fiber entanglement body containing ultrafine fibers having a fineness of 0.5 dtex or less, and a first polymer elastomer impregnated into the fiber entanglement body, and having a main surface which is a raised surface where ultrafine fibers are raised, and is obtained by applying a treatment solution containing phosphorus-based flame retardant particles and a second polymer elastomer to the reverse surface of a raised artificial leather having a thickness of 0.25 to 1.5 mm, and then drying the same to thereby distribute phosphorus-based flame retardant particles in a range of 200 µm or less in thickness from the reverse surface.

The artificial leather having a surface weight of 100 to 600 g/m2, more preferably 100 to 300 g/m2, particularly 170 to 300 g/m2, and especially 170 to 250 g/m2, is preferable because it sufficiently maintains high flame retardancy and the phosphorus flame retardant particles are unlikely to affect the appearance or feel of the grained surface, thereby making it difficult to reduce the luxurious feel of the surface.

As a fiber entanglement body containing ultrafine fibers having a fineness of 0.5 dtex or less, there can be mentioned fiber structures such as nonwoven fabrics, woven fabrics, and knitted fabrics containing ultrafine fibers having a fineness of 0.5 dtex or less. Among these, a nonwoven fabric of ultrafine fibers is particularly preferable because it has high homogeneity, and thus a napped artificial leather having excellent flexibility and fidelity can be obtained. In the present embodiment, as a fiber entanglement body of ultrafine fibers, a nonwoven fabric of ultrafine fibers will be described in detail as a representative example.

As a method for producing a nonwoven fabric of ultrafine fibers, for example, a method may be exemplified in which a web is produced by melt-spinning a sea-island composite fiber, the web is entangled, and then a sea component is selectively removed from the sea-island composite fiber to form ultrafine fibers. As a method for producing a web, a method may be exemplified in which long-fiber sea-island composite fibers spun by a spun bond method or the like are captured on a net without being cut to form a long-fiber web, or a method in which long-fiber webs are cut into staples to form a short-fiber web. Of these, a long-fiber web is particularly preferable in that it has excellent density and fidelity. In addition, a fusion treatment may be performed on the formed web in order to provide shape stability. As the entanglement treatment, for example, a method may be exemplified in which 5 to 100 webs are overlapped and needle punched or high-pressure water jet treated. In addition, in any process from removing the sea component of the sea-island type composite fiber to forming ultrafine fibers, by performing fiber shrinkage treatment such as heat shrinkage treatment using steam, the sea-island type composite fiber can be densified and the sense of solidity can be improved.

In this embodiment, a detailed description will be given of a case where a sea-island composite fiber is used, but an ultrafine fiber-generating fiber other than a sea-island composite fiber may be used, and furthermore, a nonwoven fabric may be manufactured by directly spinning ultrafine fibers without using an ultrafine fiber-generating fiber. In addition, specific examples of ultrafine fiber-generating fibers other than a sea-island composite fiber include, without particular limitation, fibers capable of forming ultrafine fibers, such as a peeling split type fiber in which a plurality of ultrafine fibers are lightly bonded and formed immediately after spinning and then released by mechanical operation to form a plurality of ultrafine fibers, or a petal-shaped fiber formed by alternately gathering a plurality of resins in a petal-like shape in a melt spinning process.

The resin of the island component of the island-type composite fiber for forming ultrafine fibers is not particularly limited. Specifically, for example, aromatic polyesters such as polyethylene terephthalate (PET), isophthalic acid-modified PET, sulfoisophthalic acid-modified PET, polybutylene terephthalate, and polyhexamethylene terephthalate; aliphatic polyesters such as polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, and polyhydroxybutyrate-polyhydroxyvalerate resin; polyamides (nylons) such as 6-polyamide, polyamide 66, polyamide 10, polyamide 11, polyamide 12, and polyamide 6-12; polyolefins such as polypropylene, polyethylene, polybutene, polymethylpentene, and chlorinated polyolefins, and the like. These may be used alone or in combination of two or more. Among these, PET or modified PET, polylactic acid, polyamide 6, polyamide 12, polyamide 6-12, polypropylene, etc. are preferable.

In addition, as the resin of the sea component forming the sea-type composite fiber, a resin having different solubility in a solvent or decomposition in a decomposer than the resin of the island component is selected. Specific examples of the thermoplastic resin constituting the sea component include, for example, water-soluble polyvinyl alcohol, polyethylene, polypropylene, polystyrene, ethylene propylene resin, ethylene vinyl acetate resin, styrene ethylene resin, and styrene acrylic resin.

The sea component of the sea-island type composite fiber is dissolved or decomposed and removed at an appropriate stage after the web is formed. By such decomposition and removal or dissolution and extraction, the sea-island type composite fiber is converted into ultrafine fibers, and ultrafine fibers in the form of a bundle are formed.

The fineness of the ultrafine fibers is 0.5 dtex or less, preferably 0.001 to 0.4 dtex, and further preferably 0.01 to 0.3 dtex. If the fineness of the ultrafine fibers exceeds 0.5 dtex, the luxurious feel of the napped surface tends to deteriorate. In addition, the fineness can be determined by photographing a cross-section in the thickness direction of the napped artificial leather at a magnification of 2000 times with a scanning electron microscope (SEM), obtaining the cross-sectional area of a single fiber, and calculating the fineness of one single fiber from the cross-sectional area and the specific gravity of the resin forming the ultrafine fiber. The fineness can be defined as the average value of the finenesses of 100 single fibers uniformly obtained from the photographed images.

The first polymer elastomer is evenly applied to the entire nonwoven fabric. The first polymer elastomer imparts shape stability to a fiber entanglement including ultrafine fibers having a fineness of 0.5 dtex or less by restraining the ultrafine fibers, or imparts a luxurious feel to the napped surface. Examples of the first polymer elastomer include polyurethane, acrylonitrile elastomer, olefin elastomer, polyester elastomer, polyamide elastomer, and acrylic elastomer. These may be used alone or in combination of two or more. Among these, polyurethane is preferable.

In addition, polyurethane tends to be more flammable than ultrafine fibers. In the napped artificial leather of the present embodiment, by applying a flame retardant to the reverse side of the napped artificial leather, the deterioration of the appearance of the napped surface due to the application of the flame retardant can be suppressed.

When using polyurethane, it is particularly preferable in that the flame retardancy of the raised surface can be improved by using a specific polyurethane. This specific polyurethane is a reaction product of a polyurethane raw material including a high molecular weight polyol, an organic polyisocyanate, and a chain extender, wherein 60 mass% or more of the high molecular weight polyol is a polycarbonate polyol, and further, the average repeating carbon number excluding the reactive functional group is 6.5 or less, and the organic polyisocyanate includes at least one selected from the group consisting of 4,4'-dicyclohexyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate. This polyurethane has excellent self-extinguishing properties, small calorific value and smoke amount, and exhibits a high level of flame retardancy.

Specific examples of polycarbonate polyols include, for example, polycarbonate polyols such as polyhexamethylene carbonate diol, poly(3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, and polycyclohexane carbonate diol, and copolymers thereof.

In addition, the polymer polyol may include a polymer polyol other than polycarbonate polyol as long as it does not exceed 40 mass%. Specific examples of the polymer polyol other than polycarbonate polyol include: polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and poly(methyltetramethylene glycol), and copolymers thereof; polyester polyols such as polyethylene adipate diol, poly1,2-propylene adipate diol, poly1,3-propylene adipate diol, polybutylene adipate diol, polybutylene sebacate diol, polyhexamethylene adipate diol, poly(3-methyl-1,5-pentane adipate) diol, poly(3-methyl-1,5-pentane sebacate) diol, and polycaprolactone diol, and copolymers thereof; polycarbonate polyol having 6.5 or more carbon atoms; Examples include polyester carbonate polyol. These may be used alone or in combination of two or more.

The content ratio of polycarbonate polyol contained in the high molecular weight polyol used in the production of a specific polyurethane is 60 mass% or more, and preferably 70 mass% or more. When the content ratio of polycarbonate polyol contained in the high molecular weight polyol is less than 60 mass%, the calorific value or smoke amount of the polyurethane increases.

In addition, the average repeating carbon number excluding the reactive functional group of the high molecular weight polyol used in the production of a specific polyurethane is 6.5 or less, and preferably 6.0 or less. Even when the average repeating carbon number excluding the reactive functional group of the high molecular weight polyol exceeds 6.5, the calorific value or smoke amount of the polyurethane increases.

Here, the average repeating carbon number excluding the reactive functional group of the polymer polyol is defined as the carbon number of the hydrocarbon included in the repeating unit of the polymer polyol including a carbonate group (-OCOO-), an ester group (-COO-), an ether group (-O-), etc., excluding the reactive functional group in the polymer polyolization reaction. In addition, when two or more types of polymer polyols are used, the average repeating carbon number excluding the reactive functional group is a value calculated by taking the average value of the carbon numbers of the hydrocarbon included in the repeating unit of the polymer polyol including two or more types of carbonate groups, ester groups, ether groups, etc., excluding the reactive functional group.

As for the molecular weight of the high molecular weight polyol, it is preferable that the average molecular weight be 200 to 6000, further, 500 to 5000.

In addition, the organic polyisocyanate used in the production of a specific polyurethane includes at least one selected from the group consisting of 4,4'-dicyclohexyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate. In addition, it is preferable that the organic polyisocyanate includes at least one selected from the group consisting of 4,4'-dicyclohexyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate in an amount of 60 mass% or more, more preferably 70 mass% or more, particularly preferably 80 mass% or more, from the viewpoint of obtaining a polyurethane having excellent self-extinguishing properties and a small calorific value and smoke amount.

In addition to high molecular weight polyol, polyfunctional alcohols such as trifunctional alcohols or tetrafunctional alcohols or short-chain alcohols such as ethylene glycol may be used as polyurethane raw materials. These may be used alone or in combination of two or more.

In addition to 4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, other organic isocyanates may be used in combination with the polyurethane raw material. Specific examples of such organic isocyanates include non-sulfur modified diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and norbornene diisocyanate, aliphatic or alicyclic diisocyanates; and aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and xylylene diisocyanate polyurethane. In addition, if necessary, polyfunctional isocyanates such as trifunctional isocyanates or tetrafunctional isocyanates, or blocked polyfunctional isocyanates may be used in combination. These can be used alone or in combination of two or more.

As a chain extender used in the production of a specific polyurethane, a low-molecular-weight compound having two or more active hydrogens is used. Specific examples of the chain extender include diamines such as hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and its derivatives, adipate dihydrazide, and isophthalic dihydrazide; triamines such as diethylenetriamine; tetramines such as triethylenetetramine; diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis(β-hydroxyethoxy)benzene, and 1,4-cyclohexanediol; triols such as trimethylolpropane; pentaols such as pentaerythritol; aminoalcohols such as aminoethyl alcohol and aminopropyl alcohol, etc. These may be used alone or in combination of two or more. Among these, it is preferable to use a combination of two or more of hydrazine, piperazine, ethylenediamine, hexamethylenediamine, isophoronediamine and derivatives thereof, triamines such as diethylenetriamine, ethylene glycol, propylene glycol, 1,4-butanediol and derivatives thereof, in terms of excellent mechanical properties. In addition, during the chain extension reaction, a chain extender may be used in combination with monoamines such as ethylamine, propylamine, and butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; and monools such as methanol, ethanol, propanol, and butanol. Among these, a chain extender having 6 or fewer carbon atoms excluding the reactive functional group is particularly preferable in terms of excellent self-extinguishing properties and small calorific value and smoke amount.

In addition, in order to control the water absorption rate of polyurethane or the adhesion to ultrafine fibers or the hardness, a crosslinking agent containing two or more functional groups in the molecule that can react with the functional groups of the monomer units forming the polyurethane, for example, a self-crosslinking compound such as a carbodiimide compound, an epoxy compound, an oxazoline compound, a polyisocyanate compound, or a polyfunctional block isocyanate compound, may be added to form a crosslinking structure in the polyurethane.

As polyurethane emulsions, examples thereof include forced emulsification-type polyurethane emulsions in which an emulsifier is added and the polyurethane skeleton does not have an ionic group, self-emulsification-type polyurethane emulsions in which the polyurethane skeleton has an ionic group such as a carboxyl group, a sulfonic acid group, or an ammonium group and is emulsified by self-emulsification, and polyurethane emulsions in which an emulsifier and an ionic group of the polyurethane skeleton are used together. For example, in order to introduce a carboxyl group into the polyurethane skeleton, a method can be used in which a unit such as a carboxyl group-containing diol such as 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butanoic acid, or 2,2-bis(hydroxymethyl)valeric acid is inserted into the polyurethane skeleton.

The first polymer elastomer is, for example, impregnated with a fiber entanglement of ultrafine fiber-forming fibers such as island-shaped composite fibers for forming ultrafine fibers, or with an emulsion of a polymer elastomer such as a polyurethane emulsion, or a solution of a polymer elastomer such as a polyurethane solution, and then coagulated, thereby providing the fiber entanglement. Examples of methods for impregnating the fiber entanglement with the emulsion or solution of the first polymer elastomer include a method using a knife coater, a bar coater, or a roll coater, and a dipping method. In addition, when an emulsion is used, the polymer elastomer can be coagulated by a method of heat treatment in a drying device at 50 to 200°C, a method of heat treatment in a dryer after infrared heating, a method of heat treatment in a dryer after steam treatment, or a method of heat treatment in a dryer after ultrasonic heating, or a method of heat treatment in a dryer after ultrasonic heating, or a method combining these.

In addition, as a polyurethane emulsion, it is preferable to use a polyurethane emulsion containing, for example, 20 to 100 mass% of self-emulsifying polyurethane and 0 to 80 mass% of forced emulsifying polyurethane by combining self-emulsifying polyurethane and forced emulsifying polyurethane, since a flexible texture can be obtained. In addition, the average particle size of the polyurethane emulsion is preferably 0.01 to 1 ㎛, more preferably 0.03 to 0.5 ㎛.

When a polyurethane emulsion is impregnated into a fiber entanglement and then dried, the emulsion may migrate to the surface of the fiber entanglement, making it difficult to apply it uniformly in the thickness direction. In such a case, migration can be suppressed, for example, as follows: by adjusting the dispersed particle size of the emulsion; by adjusting the type or amount of the ionic group of the polyurethane; by adding an ammonium salt whose pH changes at a temperature of about 40 to 100°C to lower the water dispersion stability; or by adding a monovalent or divalent alkali metal salt or alkaline earth metal salt, a nonionic emulsifier, an associative water-soluble thickener, an associative heat-sensitive gelling agent such as a water-soluble silicone compound, or a water-soluble polyurethane compound, to lower the water dispersion stability.

The first polymer elastomer is preferably one having a 100% modulus of 0.5 to 7 MPa, more preferably 1 to 5 MPa, in that a flexible texture can be obtained and a smooth surface touch and surface properties can be imparted. If the 100% modulus is too low, when the piled artificial leather is heated, the first polymer elastomer tends to soften and restrain the ultrafine fibers, thereby reducing the flexible texture and smooth surface touch. In addition, if the 100% modulus is too high, the smooth surface touch of the piled artificial leather tends to be reduced or the texture tends to become hard.

The proportion of the first polymer elastomer included in the artificial leather with raised hair is preferably 3 to 50 mass%, more preferably 3 to 40 mass%, particularly 3 to 35 mass%, and especially 7 to 25 mass%, from the viewpoint of excellent balance between high flame retardancy, surface luxuriousness, dimensional stability, and surface properties.

The fiber entanglement containing the first polymer elastomer is, if necessary, subjected to a wet heat shrinkage treatment or a press treatment, so as to adjust the apparent density, apparent weight, and thickness, and is finished as a raw material of artificial leather. Then, the raw material of the artificial leather is sliced as necessary. Then, at least one side of the raw material of the artificial leather is subjected to a buffing treatment using a contact buff, an emery buff, or the like, so that a raw material of a raw material of a raised artificial leather having a raised surface is produced.

Buffing is preferably performed using, for example, sandpaper or emery paper having a grit count of 120 to 600. In this way, the fibers of the buffed surface are raised, and a napped artificial leather having a napped surface in which ultrafine fibers are raised is produced. The napped artificial leather may further be subjected to finishing treatments such as dyeing, rubbing softening, blanking softening, reverse seal brushing, stain-proofing, hydrophilization, lubricant treatment, softener treatment, antioxidant treatment, ultraviolet absorber treatment, and fluorescent agent treatment, if necessary.

The thickness of the raw material of the raised artificial leather is almost equal to the thickness of the finally obtained raised artificial leather. The thickness of the raw material of the raised artificial leather is 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, and more preferably 0.4 to 1.0 mm. When the thickness of the raw material of the raised artificial leather exceeds 1.5 mm, it becomes difficult to obtain a sufficient flame retardant effect.

The raised artificial leather is obtained by a flame retardant treatment, which is a treatment in which a treatment solution containing phosphorus-based flame retardant particles and a second polymer elastomer is applied to the reverse side of the raised artificial leather, which is the main body of the raised artificial leather and has a thickness of 0.25 to 1.5 mm, and then dried to cause the phosphorus-based flame retardant particles to be distributed unevenly over a range of 200 ㎛ or less in thickness from the reverse side.

Here, in the case of the raised artificial leather, the fact that the phosphorus-based flame retardant particles are distributed in a range of 200 µm or less in thickness from the back surface relative to the main surface means that most of the phosphorus-based flame retardant particles present in the raised artificial leather, specifically, 90 to 100 mass%, and more preferably 95 to 100 mass% of the phosphorus-based flame retardant particles, are present in a range of 200 µm or less in thickness from the back surface relative to the main surface. The thickness from the back surface relative to the main surface where the phosphorus-based flame retardant particles are distributed is preferably 50 to 200 µm, more preferably 70 to 180 µm, and especially 100 to 150 µm. The thickness of the region in which the phosphorus-based flame retardant particles of the raised artificial leather are distributed is confirmed by observing a cross-section in a direction parallel to the thickness direction of the raised artificial leather with a scanning electron microscope. In addition, the ratio of the thickness of the region where the halogen-free flame retardant particles are distributed to the total thickness of the artificial leather for raising is preferably 10 to 60%, or even 10 to 50%, in that it does not impair the luxurious feel of the surface and it is easy to impart a high level of flame retardancy by using a non-halogen flame retardant.

In this way, by distributing phosphorus flame retardant particles so that the phosphorus atom conversion content ratio is 1 to 6 mass% within a range of 200 ㎛ or less in thickness from the back surface of the artificial leather, flame retardancy can be imparted using a non-halogen flame retardant without impairing the luxurious feel of the surface.

The content ratio of the phosphorus-based flame retardant particles distributed in a range of 200 µm or less in thickness from the back surface of the raised artificial leather in the raised artificial leather is 1 to 6 mass%, and preferably 1.5 to 5.5 mass%, in terms of phosphorus atoms. When the content ratio of the phosphorus-based flame retardant particles in terms of phosphorus atoms is less than 1 mass%, it becomes difficult to obtain a high level of flame retardancy. Furthermore, when the content ratio of the phosphorus-based flame retardant particles in terms of phosphorus atoms exceeds 6 mass%, it becomes difficult to fix and distribute the phosphorus-based flame retardant particles in a range of 200 µm or less in thickness from the back surface without falling off, and furthermore, the flexibility of the raised artificial leather is lost or the luxurious feel of the surface deteriorates.

In addition, the phosphorus flame retardant particles included in the artificial leather having a nap are particles of a flame retardant compound containing phosphorus atoms, which are solid particles at room temperature, having an average particle size of 0.1 to 30 ㎛, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point, or if there is no melting point, a decomposition temperature of 150°C or more.

The average particle size of the phosphorus flame retardant particles is preferably 0.1 to 30 ㎛, more preferably 0.5 to 30 ㎛, more preferably 0.5 to 15 ㎛, and particularly preferably 1 to 10 ㎛. When the average particle size exceeds 30 ㎛, it becomes difficult to sufficiently penetrate the phosphorus flame retardant particles into a range of 200 ㎛ or less in thickness from the back surface of the napped artificial leather so that the content ratio of the phosphorus flame retardant particles becomes 1 to 6 mass% in terms of the content ratio converted to phosphorus atoms, and the flame retardancy effect tends to become insufficient. In addition, when the average particle size is less than 0.1 ㎛, the particles tend to aggregate and become unevenly dispersed, easily causing unevenness in the flame retardancy.

In addition, the phosphorus atom content of the phosphorus-based flame retardant particles is preferably 14 mass% or more, 15 mass% or more, and more preferably 20 mass% or more. In addition, it is preferably 30 mass% or less, and more preferably 28 mass% or less. When the phosphorus atom content of the phosphorus-based flame retardant particles is less than 14 mass%, it becomes difficult to provide a high level of flame retardancy. In addition, when the phosphorus atom content of the phosphorus-based flame retardant particles is excessively high, the flame retardant tends to fall off and adhere to the surface, which tends to adversely affect the surface appearance and fastness.

In addition, the phosphorus flame retardant particles preferably have a solubility in water at 30°C of 0.2 mass% or less, and preferably 0.15 mass% or less. If phosphorus flame retardant particles having a solubility in water at 30°C exceeding 0.2 mass% are used, they tend to absorb moisture during manufacture or use, or to bleed to the nap surface when wet with water. In addition, the solubility of the phosphorus flame retardant particles in water at 30°C is measured by adding a small amount of phosphorus flame retardant particles to 100 g of water at 30°C, and measuring the maximum mass of the phosphorus flame retardant particles that can be dissolved.

In addition, among the phosphorus flame retardant particles, those having a hydrothermal solubility in hot water at 90°C of 5 mass% or less, more preferably 3 mass% or less, are preferable because, when producing or using a raised artificial leather, the flame retardant is unlikely to bleed onto the raised surface when in contact with hot water, and dimensional changes in the raised artificial leather due to moisture absorption of the flame retardant can be suppressed. In addition, the hydrothermal solubility of the phosphorus flame retardant particles in hot water at 90°C is measured by adding a small amount of the phosphorus flame retardant particles to 100 g of water at 90°C and measuring the maximum mass of the phosphorus flame retardant particles that can be dissolved.

In addition, the phosphorus flame retardant particles are a solid in the form of particles at room temperature, having a melting point, or a decomposition temperature when no melting point exists, of 150°C or higher, and preferably 200°C or higher. When the melting point, or the decomposition temperature when no melting point exists, is lower than 150°C, in the drying process after the flame retardant is applied during the production of the raised artificial leather, the flame retardant softens, making it difficult to maintain the form of particles. As a result, the phosphorus flame retardant particles gather ultrafine fibers, and the surface touch and texture of the raised surface deteriorate. In addition, when the raised artificial leather is burned, it is easy for a melting drop to occur, making it difficult to maintain a high level of flame retardancy.

Here, the melting point of the phosphorus flame retardant particles is specified by the melting peak temperature of thermogravimetric differential thermal analysis (TG-DTA) or differential scanning calorimetry analysis (DSC). In addition, the decomposition temperature in the case where there is no melting point is specified by the decomposition initiation temperature of thermogravimetric differential thermal analysis (TG-DTA). The measurement conditions are not particularly limited, but the measurement is performed at a heating rate of 5 to 10°C/min in a nitrogen atmosphere.

Examples of the phosphorus flame retardant particles include organic phosphinic acid metal salts such as dialkylphosphinic acid metal salts and monoalkylphosphinic acid metal salts; aromatic phosphonic acid esters; and phosphoric acid ester amides. These may be used alone or in combination of two or more. Among these, dialkylphosphinic acid metal salts or monoalkylphosphinic acid metal salts are preferable because they have high water resistance and heat resistance, a high phosphorus atom content, and a high flame retardant effect.

The second polymer elastomer used for fixing the phosphorus flame retardant particles included in the artificial leather may be the same as or different from the first polymer elastomer. Among these, polyurethane is preferable in that it has an excellent balance of physical properties. In addition, the second polymer elastomer is preferable to have a 100% modulus of 0.5 to 5 MPa, more preferably 1 to 4 MPa, in that it provides a flexible texture and can suppress the detachment of the flame retardant.

The method for applying a treatment solution containing phosphorus-based flame retardant particles and a second polymer elastomer to the reverse side of a raw-faced artificial leather having a thickness of 0.25 to 1.5 mm is not particularly limited. Specifically, a method may be exemplified in which a treatment solution containing phosphorus-based flame retardant particles and a second polymer elastomer is applied to the reverse side of a raw-faced artificial leather by, for example, gravure coating, direct coating, roll coating, or spray coating while adjusting the application amount or viscosity.

The viscosity of the treatment solution containing the phosphorus-based flame retardant particles and the second polymer elastomer is preferably 200 to 10,000 mPa·sec, more preferably 500 to 5,000 mPa·sec, because this makes it easy for the phosphorus-based flame retardant particles and the second polymer elastomer to appropriately sink from the reverse side of the raw surface of the grained artificial leather and to be distributed unevenly in a range of 200 ㎛ or less in thickness, thereby imparting high flame retardancy to the grained artificial leather without impairing the luxurious feel of the grained surface, which is the main surface.

As a treatment liquid containing the second polymer elastomer, for example, a treatment liquid prepared by dispersing phosphorus flame retardant particles in a polyurethane emulsion is preferably used. When using a polyurethane emulsion, the average particle size of the emulsion is preferably 10 ㎛ or less, more preferably 5 ㎛. In addition, the drying temperature of the treatment liquid is preferably 100 to 160°C.

The content ratio of phosphorus-based flame retardant particles in the total amount of phosphorus-based flame retardant particles and the second polymer elastomer is preferably 10 to 30 mass%, more preferably 12 to 30 mass%, and particularly preferably 15 to 25 mass%, in terms of phosphorus atoms. When the content ratio of phosphorus-based flame retardant particles in the total amount of phosphorus-based flame retardant particles and the second polymer elastomer is the above ratio, it is preferable because the influence of the flame retardancy reduction due to combustion of the second polymer elastomer is small.

In addition, the content ratio of phosphorus-based flame retardant particles in the total amount of phosphorus-based flame retardant particles and the second polymer elastomer is in the range of 10 to 30 mass% in terms of phosphorus atoms, and further, in terms of the mass of the phosphorus-based flame retardant particles, it is preferably 60 to 90 mass%, more preferably 70 to 85 mass%.

In addition, the proportion of the second polymer elastomer included in the artificial leather with a raised surface is not particularly limited, but is preferably 2 to 15 mass%, more preferably 4 to 10 mass%, in that it can sufficiently fix the phosphorus flame retardant particles while suppressing the reduction in flame retardancy due to the provision of the second polymer elastomer.

The polymer elastomer may be impregnated into the interior of the fiber bundle, or may be attached to the exterior of the fiber bundle, when the ultrafine fibers form a fiber bundle derived from the sea-island composite fiber. When the sea-island composite fiber is processed to become ultrafine fibers, the thermoplastic resin of the sea component is removed from the sea-island composite fiber, and a void is formed inside the ultrafine fiber bundle. Therefore, the second polymer elastomer provided after the sea-island composite fiber is processed to become ultrafine fibers easily binds the ultrafine fibers forming the fiber bundle by impregnating them into the interior of the fiber bundle. Therefore, the second polymer elastomer impregnated inside the ultrafine fiber bundle contributes to improving the shape retention of the fiber entanglement by binding the ultrafine fiber bundle.

The ratio of the total amount of the polymer elastomer including the first polymer elastomer and the second polymer elastomer included in the artificial leather of the pu-reinforced polyurethane is preferably 2 to 40 mass%, more preferably 5 to 35 mass%, from the viewpoint of minimizing the effect of the reduction in flame retardancy due to combustion of the polyurethane.

In addition, the content ratio of the phosphorus flame retardant particles in the total amount of the polymer elastomer including the phosphorus flame retardant particles and the first polymer elastomer and the second polymer elastomer is preferably 5 to 20 mass%, more preferably 6 to 20 mass%, in terms of phosphorus atoms, from the viewpoint of providing an excellent balance between flame retardancy and the flexibility of the artificial leather with raised hair.

The total apparent weight of the polymer elastomer including the first polymer elastomer and the second polymer elastomer contained in the napped artificial leather is preferably 10 to 150 g/m2, more preferably 10 to 100 g/m2, and particularly preferably 10 to 50 g/m2, from the viewpoint of obtaining napped artificial leather having a particularly excellent balance of self-stretching properties and surface luxuriousness.

For the purpose of improving the smoothness of the surface and making the surface touch smooth, a flexible processing may be performed on the raised artificial leather. For the flexible processing, for example, a method may be used in which the raised artificial leather is pressed against an elastic sheet, mechanically shrunk in the vertical direction (MD of the manufacturing line), and then heat-set is performed by heat-treating in that shrunken state.

The thickness of the raised artificial leather is 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm, and more preferably 0.4 to 1.0 mm. When the thickness of the raised artificial leather is less than 0.25 mm, the flame retardant is easily exposed to the surface, which deteriorates the surface quality and surface touch. In addition, when the thickness of the raised artificial leather exceeds 1.5 mm, the flame retardancy deteriorates.

In addition, the apparent density of the raised artificial leather is preferably 0.25 to 0.75 g/cm3, or even 0.35 to 0.65 g/cm3, because the surface fiber density is high, the raised surface has a good feel and surface touch, and the balance between faithfulness and flexible texture is excellent.

The raised artificial leather is also preferably used as a wall covering material in which the raised artificial leather and an interior substrate (backing board) are bonded together with an adhesive for composite, for example. Specific examples of the interior substrate include, for example, concrete, brick, tile, porcelain tile, fiber-reinforced cement board, glass fiber-incorporated cement board, calcium silicate board, steel, aluminum, metal board, glass, mortar, plaster, stone, gypsum board, rock wool, glass wool board, wood wool cement board, hard wood wool cement board, pulp cement board, flame-retardant plywood, and the like. Among these, concrete, brick, tile, porcelain tile, fiber-reinforced cement board, glass fiber-incorporated cement board, calcium silicate board, steel, aluminum, metal board, and glass are preferable in that combustibility is suppressed when combined with the raised artificial leather.

Also, examples of adhesives for composites include starch-based, (alkyl)cellulose-based, vinyl acetate-based, ethylene vinyl acetate-based, acrylic resin-based, polyurethane-based, chloroprene-based, phenol-based, nitrile-based, ester-based, silicone-based, fluorine-based, and copolymers or mixtures thereof, or adhesives mixed with metal compounds such as metal salts or hydroxides. Among these, from the viewpoint of suppressing flammability when combined with raised artificial leather, adhesives mixed with starch-based, (alkyl)cellulose-based, vinyl acetate-based, chloroprene-based, phenol-based, nitrile-based, fluorine-based, silicone-based, and copolymers or mixtures thereof, or adhesives mixed with metal salts or hydroxides can be cited.

The flame retardancy of composite materials formed by bonding an inner lining to the back of a pile artificial leather with an adhesive can be evaluated using a cone calorimeter of ISO5660-1. Flame retardancy evaluated by a combustion test using a cone calorimeter includes the total calorific value by combustion (THR; MJ/㎡), the maximum calorific value by combustion per unit area and per unit time (PHRR; kW/㎡), and the maximum average rate of heat dissipation (MARHE; kW/㎡).

A composite material formed by bonding an inner lining to the back of a synthetic leather with an adhesive can realize a composite material having a total calorific value (THR) of 10 MJ/m2 or less, and further 8 MJ/m2 or less. In addition, the composite material of the present embodiment can realize a composite material having a maximum calorific value (PHRR) of 250 kW/m2 or less, and further 200 kW/m2 or less. In addition, the composite material of the present embodiment can realize a composite material having a maximum average rate of heat dissipation (MARHE; kW/m2) of 90 kW/m2 or less.

In addition, since the raised artificial leather has a high level of flame retardancy, a luxurious surface feel, a flexible texture, and a sense of fullness, it is preferably used in applications that require a high level of flame retardancy, such as self-extinguishing properties, low heat generation properties, and low smoke properties, such as seats or sofa materials for public transport such as airplanes, ships, railways, and vehicles, or interior walls of public buildings such as hotels and department stores.

Example

Hereinafter, the present invention will be described more specifically by examples. In addition, the scope of the present invention is not limited at all by the examples.

First, the evaluation method used in this example is summarized and explained.

(Surface luxury)

The grain surface of the artificial leather was touched and judged according to the following criteria.

A: The surface touch was smooth and there was no rough texture caused by the flame retardant particles.

B: The surface feels rough to the touch and lacks a sense of luxury.

C: The texture is hard and lacks a sense of luxury.

D: During storage, the flame retardant particles bled and the surface became white.

(thickness, apparent weight, apparent density)

According to JIS L1913, the thickness (mm) and apparent weight (g/cm2) of the raised artificial leather were measured, and the apparent density (g/cm3) was calculated by converting the apparent weight into the thickness.

(Measurement of the thickness of the region where the phosphorus flame retardant particles attached to the polymer elastomer are distributed)

The artificial leather with a raised surface was cut in the thickness direction, 10 points were selected evenly from the entire cross-section in the thickness direction, and the thickness of the region where the phosphorus flame retardant particles existed was measured at 10 points from the reverse side at a magnification of 100 times using a scanning electron microscope. Then, the average value of the 8 points excluding the maximum and minimum thickness values was defined as the thickness where the phosphorus flame retardant particles were distributed.

(Average particle size of flame retardant particles)

The artificial leather with a raised surface was cut in the thickness direction, 10 points were selected evenly from the entire cross-section in the thickness direction, and an area where phosphorus flame retardant particles existed was selected from the back surface at a magnification of 1000 times using a scanning electron microscope, and the diameters of 10 particles were measured. Then, the average value of the diameters of 8 particles excluding the maximum and minimum values was taken as the average particle diameter of the phosphorus flame retardant particles.

(Vertical combustion test: self-extinguishing)

The vertical flame retardancy of the napped artificial leather was measured according to the combustion test standard for aircraft interior materials of the United States of America, FAR25 Appendix F Part1 (a) (1) (ii). Specifically, the napped artificial leather was cut to 50.8 mm × 304.8 mm to prepare a test piece. Then, the test piece was vertically fixed to the sample holder of the combustion test apparatus. The burner was placed directly below one end of the test piece, and after ignition for 12 seconds, the combustion distance, extinguishment time, and drop extinguishment time of the test piece were measured. The average of n = 10 was calculated.

(horizontal combustion test)

A horizontal combustion test was performed on a raised artificial leather according to the combustion test standard of FMVSS302. Specifically, a raised artificial leather was cut to 102 mm × 356 mm, and a test piece was prepared by drawing a mark at 38 mm from one end of the sample. Then, the test piece was horizontally fixed to a sample holder of a combustion test device. A burner was placed on one end of the sample on the side where the mark was drawn, and after contact with the burner for 15 seconds, the combustion distance and combustion time of the test piece were measured. The average of n = 10 was calculated. A case where extinguishment occurred before the mark was referred to as self-extinguishment before mark (SE), a case where the burn distance was 50 mm or less and the burn time was 60 seconds or less beyond the mark was referred to as self-extinguishment, a burn rate of 100 mm/min or less was referred to as delayed burn rate, and a burn rate of 100 mm/min or more was referred to as easy burn rate.

〈Evaluation of composite materials using synthetic leather with a raised surface〉

Composite materials made by compositing artificial leather with raised padding were evaluated according to the following evaluation methods.

(Combustion calorific value test)

As a wall-mounted interior material, a composite material was manufactured by bonding a raised artificial leather to a calcium silicate board having a thickness of 11 mm and a density of 870 kg/㎥ using a starch-vinyl acetate adhesive (solid content 65 g/㎡). This was heated and burned for 20 minutes with a 50 kW/㎡ heater according to the cone calorimeter method of ISO5660-1, and the total calorific value (THR), maximum calorific value (PHRR), the time exceeding 200 kW of the peak calorific value after 20 minutes, and the maximum average rate of heat dissipation (MARHE) were measured.

(Combustion smoke test)

As a wall-mounted interior material, a composite material was manufactured by bonding artificial leather with a starch-vinyl acetate adhesive (solid content 65 g/㎡) to a calcium silicate board having a thickness of 11 mm and a density of 870 kg/㎥. This was heated and burned for 20 minutes with a 50 kW/㎡ heater according to the cone calorimeter method of ISO5660-1, and the smoke increase concentration (SPR) was measured.

[Example 1]

A sea-island type composite fiber was melt-spun using water-soluble thermoplastic polyvinyl alcohol (PVA) as a sea component resin and isophthalic acid-modified polyethylene terephthalate as an island component resin. Specifically, molten resins of the sea component resin and the island component resin were respectively supplied to a composite spinning die having nozzle holes arranged to form a cross-section in which 25 island component resins were distributed among the sea component resin, and the molten fibers of the sea-island type composite fiber were discharged from the nozzle holes. At this time, the pressure was adjusted while supplying so that the mass ratio of the sea component and the island component became sea component/island component = 25/75.

And, by drawing the molten fiber of the sea-island type composite fiber by a suction device, the sea-island type composite fiber with a fineness of 3.3 dtex was spun. The spun sea-island type composite fiber was continuously deposited on a movable net and lightly pressed by a heated metal roll, so that the occurrence of fluff on the surface was suppressed. And, after the sea-island type composite fiber was peeled from the net, it was passed between a metal roll and a back roll and heat-pressed, thereby obtaining a web with an apparent weight of 31 g/㎡.

Next, using a cross-lapper device, the webs were overlapped in eight layers so that the total apparent weight became 300 g/㎡, and then entangled by alternately needle-punching from both sides. The apparent weight of the entangled web, which is the web after needle-punching, was 440 g/㎡.

Then, the entangled web was subjected to wet heat shrinkage for 30 seconds under the conditions of 70℃ and 50%RH humidity. The area shrinkage rate before and after the wet heat shrinkage treatment was 47%.

Then, the contracted entangled web was impregnated with an emulsion of the first polyurethane (the first polymer elastomer) containing ammonium sulfate as a gelling agent, and then dried. The first polyurethane was a reaction product of a polymer polyol having an average repeating carbon number of 6 excluding reactive functional groups as 100% polycarbonate polyol, an organic polyisocyanate being 4,4'-dicyclohexyl methane diisocyanate, and a chain extender, and was a self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa.

Then, by immersing the first polyurethane-impregnated entangled web in hot water and dissolving and removing the PVA, an artificial leather containing a nonwoven fabric in which fiber bundles containing 25 ultrafine fibers having a fineness of 0.1 dtex were three-dimensionally entangled was produced. The content of the first polyurethane in the artificial leather was 12 mass%.

Then, the raw material of the artificial leather was sliced and divided in half in the direction of thickness, and the anti-sliced surface was buffed to finish it as a raw material of artificial leather having a suede-like raw material surface. The raw material of the raw material of the raw material of the raw material of the artificial leather had a thickness of 0.5 mm, an apparent weight of 250 g/㎡, and an apparent density of 0.50 g/cm3.

Then, using a circular dyeing machine, the life of the artificial leather with raised hair was dyed, dried, impregnated with a softener, and further dried.

Then, a second polyurethane emulsion having 2000 mPa sec, in which particles of a dialkylphosphinic acid metal salt, which is a phosphorus flame retardant, are dispersed, was applied to the sliced surface of the artificial leather after dyeing to a density of 110 g/m2 using a gravure coating machine equipped with a 35-mesh gravure roll, and then the moisture was dried at 120°C. In addition, the particles of the dialkylphosphinic acid metal salt had a dispersed particle size (median diameter: _D50 ) of 4 μm as measured by a laser diffraction/scattering particle size distribution measuring device, a phosphorus atom content of 23.5 mass%, a solubility in water at 30°C of less than 0.2 mass%, and a melting point and decomposition temperature of more than 250°C.

In addition, the second polyurethane emulsion contained 10 mass% of the second polyurethane (the second polymer elastomer) and 28 mass% of the dialkylphosphinic acid metal salt. The second polyurethane was a reaction product of a polymer polyol having an average repeating carbon number of 5.5 excluding reactive functional groups as 100% polycarbonate polyol, an organic polyisocyanate being 4,4'-dicyclohexyl methane diisocyanate, and a chain extender, and was a forced emulsification-type amorphous polycarbonate urethane having a 100% modulus of 1.0 MPa.

Then, the fire-retardant treated napped artificial leather was subjected to shrinkage processing at a drum temperature of 120°C and a conveying speed of 10 m/min to shrink 5.0% in the longitudinal direction (length direction), and then a sealing treatment was applied to the surface, thereby obtaining napped artificial leather having a suede-like napped surface. The napped artificial leather had a thickness of 0.52 mm, an apparent weight of 290 g/㎡, and an apparent density of 0.56 g/cm3.

In addition, the napped artificial leather contained 10 mass% of the first polyurethane, 5 mass% of the second polyurethane, and 15 mass% of particles of the dialkylphosphinic acid metal salt. As a result, the napped artificial leather contained 2.6 mass% of the dialkylphosphinic acid metal salt in terms of phosphorus atoms. In addition, the phosphorus atom-converted mass% with respect to the particles of the dialkylphosphinic acid metal salt and the total amount of the first polyurethane and the second polyurethane was 10.3 mass%. In addition, the phosphorus atom-converted mass% with respect to the total amount of the particles of the second polyurethane and the dialkylphosphinic acid metal salt was 17.3 mass%.

And, the obtained artificial leather with raised hair was evaluated according to the evaluation method below.

The results of the above evaluation are shown in Table 1 below.

[Example 2]

In Example 1, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, a second polyurethane emulsion containing 22 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt was used, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 3]

In Example 1, a napped artificial leather was obtained and evaluated in the same manner as above, except that a raw artificial leather having a first polyurethane content of 24 mass% was used instead of a raw artificial leather having a first polyurethane content of 12 mass%. The results are shown in Table 1.

[Example 4]

In Example 1, a second polyurethane emulsion in which particles of a dialkylphosphinic acid metal salt, which is a phosphorus flame retardant, are dispersed was applied at 60 g/m2 instead of 110 g/m2, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 5]

In Example 1, instead of the nonwoven fabric having three-dimensionally entangled fiber bundles containing 25 ultrafine fibers each of 0.1 dtex, a nonwoven fabric having three-dimensionally entangled fiber bundles containing 6 ultrafine fibers each of 0.4 dtex was formed. In addition, as the first polyurethane, a self-emulsifying amorphous polycarbonate urethane was used, which is a reaction product of a polymer polyol having an average repeating carbon number excluding reactive functional groups of 4.9, an organic polyisocyanate of 4,4'-diphenylmethane diisocyanate, and a chain extender, and having a 100% modulus of 3.0 MPa in a mass ratio of 60/40 of an amorphous polycarbonate (average repeating carbon number excluding reactive functional groups of 5.5) and a polyether polyol (average repeating carbon number excluding reactive functional groups of 4). In addition, instead of the dialkylphosphinic acid metal salt as the phosphorus flame retardant particle, the monoalkylphosphinic acid metal salt shown in Table 1 was used. Other than that, the artificial leather with raised hair was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 6]

In Example 1, instead of the nonwoven fabric in which the fiber bundles containing 25 ultrafine fibers of 0.1 dtex were three-dimensionally entangled, a nonwoven fabric in which the fiber bundles containing ultrafine fibers of 0.2 dtex were three-dimensionally entangled was formed. In addition, instead of the dialkylphosphinic acid metal salt as the phosphorus flame retardant particle, the aromatic phosphonic acid ester shown in Table 1 was used. Other than these, a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 7]

In Example 1, instead of the nonwoven fabric in which fiber bundles containing 25 ultrafine fibers of 0.1 dtex were three-dimensionally entangled, a nonwoven fabric in which fiber bundles containing ultrafine fibers of 0.2 dtex were three-dimensionally entangled was formed. In addition, instead of the dialkylphosphinic acid metal salt as the phosphorus flame retardant particle, the phosphoric acid ester amide shown in Table 1 was used. Other than these, a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 8]

A sea-island type composite fiber was melt-spun using polyethylene as the sea component resin and isophthalic acid-modified polyethylene terephthalate as the island component resin. Specifically, molten resins of the sea component resin and the island component resin were respectively supplied to a composite spinning die having nozzle holes arranged to form a cross-section in which 25 island component resins were distributed among the sea component resin, and the molten fibers of the sea-island type composite fiber were discharged from the nozzle holes. At this time, the pressure was adjusted so that the mass ratio of the sea component and the island component became sea component/island component = 25/75, and the supply was performed.

And, by drawing the molten fiber of the sea-island type composite fiber by suction with a suction device, the sea-island type composite fiber was spun. The spun sea-island type composite fiber was continuously deposited on a movable net and lightly pressed with a heated metal roll, so that the occurrence of fluff on the surface was suppressed. And, after the sea-island type composite fiber was peeled from the net, it was passed between a metal roll and a back roll, heat-pressed, and a web was obtained.

Next, using a cross-lapper device, the webs were overlapped in 8 layers so that the total apparent weight became 320 g/㎡, and entangled by alternately needle-punching from both sides. Then, the entangled web was subjected to wet heat shrinkage for 30 seconds under the conditions of 70°C and 50%RH humidity.

Then, the contracted tangled web was impregnated with an N,N-dimethylformamide solution of the first polyurethane, then immersed in a mixture of N,N-dimethylformamide and water, coagulated, and then polyethylene was extracted with toluene and dried. In addition, the first polyurethane was a reaction product of a polymer polyol having a mass ratio of 75/25 of polycarbonate polyol (average repeating carbon number excluding reactive functional groups having 6) and polyester polyol (average repeating carbon number excluding reactive functional groups having 4) and an average repeating carbon number excluding reactive functional groups having 4.9, an organic polyisocyanate being 4,4'-diphenylmethane diisocyanate, and a chain extender, and was an amorphous polycarbonate urethane having a 100% modulus of 5.0 MPa.

Other than that, artificial leather with raised hair was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 9]

Polyethylene as the sea component resin and 6-nylon (6-polyamide) as the island component resin were used to melt-spun island-type composite fibers. Specifically, polyethylene and 6-nylon were mixed at a mass ratio of 50/50 and melted, and the molten resin was supplied to a mixed spinning spinneret and discharged from a nozzle hole. The island count was about 600 on average, and a fiber having a density of 5.5 dtex was obtained by stretching. After crimping the fiber, it was cut to 51 mm and carded to obtain a single-fiber web having an apparent weight of 100 g/m2. This was polymerized into six layers using a cross-lapper device, and after spraying an emulsion, needle-punching was performed under the conditions of 1,500 punches/cm2, and then heat-pressing was performed to obtain a fiber entanglement having an apparent density of 0.40 g/cm3 and a thickness of 1.5 mm.

And, after impregnating the fiber entanglement with the N,N-dimethylformamide solution of the first polyurethane, it was immersed in a mixture of N,N-dimethylformamide and water, coagulated, and then polyethylene was extracted with toluene and dried. In addition, the first polyurethane was a reaction product of a polymer polyol having a mass ratio of 75/25 of polycarbonate polyol (average repeating carbon number 6 excluding reactive functional groups) and polyester polyol (average repeating carbon number 4 excluding reactive functional groups), and an average repeating carbon number excluding reactive functional groups of 4.9, an organic polyisocyanate being 4,4'-diphenylmethane diisocyanate, and a chain extender, and had a 100% modulus of 5.0 MPa, and was a polyurethane. A piled artificial leather was obtained and evaluated in the same manner as in Example 1, except that the dye was changed from disperse dyeing to alloy dyeing. The results are shown in Table 1.

[Example 10]

In Example 1, a napped artificial leather was obtained and evaluated in the same manner as in Example 1, except that a raw artificial leather having a thickness of 1.3 mm was used. The results are shown in Table 1.

[Example 11]

In Example 3, the first polymer elastomer was changed to a polyether-based polyurethane (average repeating carbon number excluding reactive functional groups: 5), and the content ratio (E) of phosphorus flame retardant particles was changed from 13 mass% to 9 mass%, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 1.

[Comparative Example 1]

In Example 1, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, a second polyurethane emulsion containing 10 mass% of the second polyurethane and 6.8 mass% of the dialkylphosphinic acid metal salt was used, and a napped artificial leather was obtained and evaluated in the same manner. In addition, the viscosity of the aqueous dispersion composed of phosphorus flame retardant particles and the second polyurethane was 100 mPa·sec. The results are shown in Table 2.

[Comparative Example 2]

In Example 1, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, an aqueous dispersion containing 28 mass% of ammonium polyphosphate was used, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 2.

[Comparative Example 3]

In Example 1, artificial leather with raised hair was obtained and evaluated in the same manner as in Example 1, except that ammonium polyphosphate shown in Table 2 was used instead of the dialkylphosphinic acid metal salt as the phosphorus flame retardant particle. The results are shown in Table 2.

[Comparative Example 4]

In Example 1, instead of the dialkylphosphinic acid metal salt as the phosphorus-based flame retardant particle, an aromatic phosphate ester shown in Table 2 was used, and a hair-raising artificial leather was obtained and evaluated in the same manner. The results are shown in Table 2. In addition, although the phosphorus-based flame retardant was treated in the form of an aqueous dispersion during flame retardant treatment, when observed in the hair-raising artificial leather, it was in the form of a resin film and not in the form of particles.

[Comparative Example 5]

In Example 4, the number of components of the detention was changed from 25 to 4, ultrafine fibers having an average fineness of 0.6 dtex were used, and the first polymer elastomer was changed to polycarbonate-based polyurethane (excluding reactive functional groups and having an average repeating carbon number of 9), and the same procedure was followed to obtain and evaluate a raised artificial leather. The results are shown in Table 2.

Referring to Tables 1 and 2, the napped artificial leathers obtained in Examples 1 to 11 were all napped artificial leathers having good surface luxuriousness, a flexible texture, and flame retardancy. In addition, the napped artificial leathers obtained in Examples 1 to 10 were napped artificial leathers having good self-extinguishing properties, low smoke emission and combustion heat generation, and very high levels of flame retardancy. On the other hand, in the napped artificial leather obtained in Comparative Example 1, in which the phosphorus-based flame retardant particles were small and the flame retardant particles were present even inside, the phosphorus-based flame retardant was exposed on the surface, resulting in poor surface luxuriousness. In addition, in the napped artificial leather obtained in Comparative Example 2, in which ammonium polyphosphate was used for the phosphorus-based flame retardant particles, bleeding occurred over time, resulting in poor surface luxuriousness. In addition, in the napped artificial leather obtained in Comparative Example 3, bleeding occurred over time, resulting in poor surface luxuriousness. In addition, Comparative Example 4, in which the phosphorus flame retardant particles were changed to aromatic phosphate ester, had a hard texture.

[Example 12]

A sea-island type composite fiber was melt-spun using PVA as the sea component resin and isophthalic acid-modified polyethylene terephthalate as the island component resin. Specifically, molten resins of the sea component resin and the island component resin were respectively supplied to a composite spinning die having nozzle holes arranged to form a cross-section in which 25 island component resins were distributed among the sea component resin, and the molten fibers of the sea-island type composite fiber were discharged from the nozzle holes. At this time, the pressure was adjusted so that the mass ratio of the sea component and the island component became sea component/island component = 25/75, and the supply was performed.

And, by drawing the molten fiber of the sea-island type composite fiber by a suction device, the sea-island type composite fiber with a fineness of 3.3 dtex was spun. The spun sea-island type composite fiber was continuously deposited on a movable net and lightly pressed by a heated metal roll, so that the occurrence of fluff on the surface was suppressed. And, after the sea-island type composite fiber was peeled from the net, it was passed between a metal roll and a back roll and heat-pressed, thereby obtaining a web with an apparent weight of 31 g/㎡.

Next, using a cross-lapper device, the webs were overlapped in eight layers so that the total apparent weight became 250 g/㎡, and then entangled by alternately needle-punching from both sides. The apparent weight of the entangled web, which is the web after needle-punching, was 350 g/㎡.

Then, the entangled web was subjected to wet heat shrinkage for 30 seconds under the conditions of 70℃ and 50%RH humidity. The area shrinkage rate before and after the wet heat shrinkage treatment was 47%.

Then, the contracted entangled web was impregnated with an emulsion of the first polyurethane containing ammonium sulfate as a gelling agent, and then dried. The first polyurethane was a self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa and containing 4,4'-dicyclohexyl methane diisocyanate as a diisocyanate component.

Then, by immersing the first polyurethane-impregnated entangled web in hot water and dissolving and removing the PVA, an artificial leather containing a nonwoven fabric in which fiber bundles containing 25 ultrafine fibers having a fineness of 0.1 dtex were three-dimensionally entangled was produced. The content of the first polyurethane in the artificial leather was 12 mass%.

Then, the raw material of the artificial leather was sliced and divided into two in the direction of thickness, and the half-sliced surface was buffed to finish the raw material of the artificial leather having a suede-like grained surface. The raw material of the artificial leather having a grained surface was 0.35 mm in thickness, 175 g/㎡ in apparent weight, and 0.50 g/cm3 in apparent density.

Then, using a circular dyeing machine, the artificial leather with raised hair was dyed, dried, impregnated with a softener, and further dried.

Then, a second polyurethane emulsion having 2000 mPa sec, in which particles of a dialkylphosphinic acid metal salt, which is a phosphorus flame retardant, are dispersed, was applied to the sliced surface of the artificial leather after dyeing to a density of 110 g/m2 using a gravure coating machine equipped with a 35-mesh gravure roll, and then the moisture was dried at 120°C. In addition, the particles of the dialkylphosphinic acid metal salt had a dispersed particle size (median diameter: _D50 ) of 4 μm as measured by a laser diffraction/scattering particle size distribution measuring device, a phosphorus atom content of 23.5 mass%, a solubility in water at 30°C of less than 0.2 mass%, and a melting point and decomposition temperature of more than 250°C.

In addition, the second polyurethane emulsion contained 10 mass% of the second polyurethane and 28 mass% of a dialkylphosphinic acid metal salt. The second polyurethane was a forced emulsion-type amorphous polycarbonate urethane having a 100% modulus of 1.0 MPa and containing 4,4'-dicyclohexyl methane diisocyanate as a diisocyanate component.

Then, the fire-retardant treated napped artificial leather was subjected to shrinkage processing at a drum temperature of 120°C and a conveying speed of 10 m/min to shrink 5.0% in the longitudinal direction (length direction), and then a sealing treatment was applied to the surface, thereby obtaining napped artificial leather having a suede-like napped surface. The napped artificial leather had a thickness of 0.4 mm, an apparent weight of 225 g/㎡, and an apparent density of 0.56 g/cm3.

In addition, the napped artificial leather contained 10 mass% of the first polyurethane, 5 mass% of the second polyurethane, and 14.4 mass% of particles of dialkylphosphinic acid metal salt. As a result, the napped artificial leather contained 3.4 mass% of dialkylphosphinic acid metal salt in terms of phosphorus atoms. In addition, the phosphorus atom-converted mass% with respect to the particles of dialkylphosphinic acid metal salt and the total amount of the first polyurethane and the second polyurethane was 11.5 mass%. In addition, the phosphorus atom-converted mass% with respect to the total amount of the particles of the second polyurethane and the dialkylphosphinic acid metal salt was 17.4 mass%.

And, the obtained artificial leather with raised hair was evaluated according to the evaluation method below.

The results of the above evaluation are shown in Table 3 below.

[Example 13]

In Example 12, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, a second polyurethane emulsion containing 22 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt was used, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 3.

[Example 14]

In Example 12, a napped artificial leather having a content of 19 mass% of the first polyurethane was produced instead of a napped artificial leather having a content of 10 mass% of the first polyurethane, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 3.

[Example 15]

In Example 12, a second polyurethane emulsion in which particles of a dialkylphosphinic acid metal salt, which is a phosphorus flame retardant, are dispersed was applied at 60 g/m2 instead of 110 g/m2, and a napped artificial leather was obtained and evaluated in the same manner. The results are shown in Table 3.

[Example 16]

In Example 12, instead of a nonwoven fabric having three-dimensionally entangled fiber bundles containing 25 ultrafine fibers each of 0.1 dtex, a nonwoven fabric having three-dimensionally entangled fiber bundles containing 6 ultrafine fibers each of 0.4 dtex was formed. In addition, instead of a self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa and containing 4,4'-diphenylmethane diisocyanate as the diisocyanate component, the first polyurethane used was a self-emulsifying polyurethane having a mass ratio of amorphous polycarbonate and polyether polyol of 60/40 and a 100% modulus of 3.0 MPa. In addition, as the phosphorus flame retardant particles, a monoalkylphosphinic acid metal salt shown in Table 3 was used instead of a dialkylphosphinic acid metal salt. Other than that, artificial leather with raised hair was obtained and evaluated in the same manner. The results are shown in Table 3.

[Example 17]

In Example 12, artificial leather with raised hair was obtained and evaluated in the same manner as in Example 11, except that an aromatic phosphonic acid ester shown in Table 3 was used instead of a dialkylphosphinic acid metal salt as the phosphorus flame retardant particle. The results are shown in Table 3.

[Example 18]

In Example 12, a synthetic leather having a raised surface was obtained and evaluated in the same manner as in Example 11, except that a phosphoric acid esteramide shown in Table 3 was used instead of a dialkylphosphinic acid metal salt as the phosphorus flame retardant particle. The results are shown in Table 3.

[Example 19]

In Example 12, polyethylene and 6-nylon were mixed at a mass ratio of 50/50, melted, and the molten resin was supplied to a mixed spinning die and discharged from a nozzle hole. The average number of strands was about 600, and a fiber having a diameter of 5.5 dtex was obtained by stretching. After crimping the fiber, it was cut to 51 mm and carded to obtain a single-fiber web having an apparent weight of 100 g/m2. This was polymerized into six layers using a cross-lapper device, and after spraying an emulsion, needle-punching was performed under the conditions of 1500 punches/cm2, followed by heat pressing to obtain a fiber entanglement having an apparent density of 0.40 g/cm3 and a thickness of 1.2 mm. Then, the fiber composite was impregnated with polyurethane having a first polyurethane, a diisocyanate component composed of 4,4'-diphenylmethane diisocyanate, a polymer polyol composed of polycarbonate polyol and polyester polyol in a mass ratio of 75/25, and a 100% modulus of 5.0 MPa, dissolved in N,N-dimethylformamide, so as to have a mass ratio shown in Table 3, and then immersed in a mixture of N,N-dimethylformamide and water, coagulated, and then polyethylene was extracted using toluene and dried. Thereafter, a pile artificial leather was obtained and evaluated in the same manner as in Example 12, except that the dye was changed from disperse dyeing to alloy dyeing. The results are shown in Table 3.

[Example 20]

In Example 19, except that the number of polymerization sheets of the single-fiber web was changed from 6 to 4, a pile artificial leather having a thickness of 0.3 mm, an apparent weight of 128 g/m2, and an apparent density of 0.43 g/cm3 was obtained and evaluated. The results are shown in Table 3.

[Example 21]

In Example 12, except that the webs were overlapped in 10 layers using a cross-lapper device so that the total apparent weight became 330 g/m2, a pile artificial leather having a thickness of 0.55 mm, an apparent weight of 300 g/m2, and an apparent density of 0.54 g/cm3 was obtained and evaluated. The results are shown in Table 3.

[Example 22]

In Example 12, a cross-lapper device was used to overlap the web in 32 layers instead of 8 layers, no shrinkage treatment was performed, and impregnation treatment was performed so that the content of the first polyurethane was 12 mass%. In the same manner, a pile artificial leather having a thickness of 1.0 mm, an apparent weight of 300 g/m2, and an apparent density of 0.30 g/cm3 was obtained and evaluated. The results are shown in Table 3.

[Comparative Example 6]

In Example 12, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, a second polyurethane emulsion containing 10 mass% of the second polyurethane and 6.8 mass% of the dialkylphosphinic acid metal salt was used, and a napped artificial leather was obtained and evaluated in the same manner. In addition, the viscosity of the aqueous dispersion composed of phosphorus flame retardant particles and the second polymer elastomer was 100 mPa·sec. The results are shown in Table 4.

[Comparative Example 7]

In Example 12, instead of the second polyurethane emulsion containing 10 mass% of the second polyurethane and 28 mass% of the dialkylphosphinic acid metal salt, an aqueous dispersion containing 28 mass% of ammonium polyphosphate having a dispersed particle size of 20 µm was used, and a hair-raising artificial leather was obtained and evaluated in the same manner. In addition, the viscosity of the aqueous dispersion composed of phosphorus flame retardant particles and the second polymer elastomer was 100 mPa·sec. The results are shown in Table 4.

[Comparative Example 8]

In Example 12, the first polyurethane, which was a self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 3.0 MPa and containing 4,4'-dicyclohexyl methane diisocyanate as the diisocyanate component, was changed to the first polyurethane, which was a self-emulsifying amorphous polycarbonate urethane having a 100% modulus of 2.0 MPa and containing 1,6-hexamethylene diisocyanate as the diisocyanate component, and further using ammonium polyphosphate shown in Table 1 instead of the dialkylphosphinic acid metal salt as the phosphorus flame retardant particle, and the like, except that a napped artificial leather was obtained and evaluated. The results are shown in Table 4.

[Comparative Example 9]

In Example 12, a hair-raising artificial leather was obtained and evaluated in the same manner as in Example 11, except that an aromatic phosphate ester shown in Table 4 was used instead of a dialkylphosphinic acid metal salt as the phosphorus-based flame retardant particle. The results are shown in Table 4. In addition, although the phosphorus-based flame retardant was treated in the form of an aqueous dispersion during flame retardant treatment, when observed in the hair-raising artificial leather, it was in the form of a resin film and not in the form of particles.

[Comparative Example 10]

In Example 12, the number of components of the detention was changed from 25 to 4, and the number of web layers of the napped artificial leather was changed from 8 to 16, but the same procedure was followed to obtain and evaluate napped artificial leather. The results are shown in Table 4.

Referring to Tables 3 and 4, the artificial leather substrates obtained in Examples 12 to 22 all had a good surface luxurious feel, a flexible texture, good self-extinguishing properties, low smoke amount and combustion heat amount, and high-level flame retardancy, resulting in a raised artificial leather. On the other hand, in Comparative Example 6, in which the phosphorus-based flame retardant particles were small and the flame retardant particles were present inside, the phosphorus-based flame retardant was exposed on the surface, resulting in a low appearance luxurious feel. In addition, in Comparative Example 7, in which ammonium polyphosphate was used for the phosphorus-based flame retardant particles, bleeding occurred over time, resulting in a poor appearance. In addition, in Comparative Example 8, bleeding occurred over time, resulting in a poor appearance. In addition, in Comparative Example 9, in which the phosphorus-based flame retardant particles were changed to an aromatic phosphate ester, the texture was hard. In addition, Comparative Example 10, which had a high degree of fineness and high apparent weight of artificial leather, had poor flame retardancy.

Claims (14)

A 0.25 to 1.5 mm thick artificial leather comprising a fiber entanglement body containing ultrafine fibers having a fineness of 0.5 dtex or less, a polymer elastomer impregnated into the fiber entanglement body, and phosphorus flame retardant particles attached to the polymer elastomer body, and having a main surface which is a surface where the ultrafine fibers are entangled,
The above polymer elastomer comprises a first polymer elastomer present over the entire thickness cross-section and a second polymer elastomer distributed over a range of a thickness of 200 ㎛ or less.
The above phosphorus flame retardant particles are attached to the second polymer elastomer, and 90 to 100 mass% of the above phosphorus flame retardant particles are distributed in a range of a thickness of 200 ㎛ or less from the back surface of the main surface, and the ratio of the thickness of the region where the phosphorus flame retardant particles are distributed to the total thickness is 10 to 50%,
The above-mentioned phosphorus flame retardant particles contain at least one compound selected from the group consisting of a dialkylphosphinic acid metal salt, a monoalkylphosphinic acid metal salt, an aromatic phosphonic acid ester, and a phosphoric acid ester amide, and further have an average particle diameter of 0.1 to 30 µm, a phosphorus atom content of 14 mass% or more, a solubility in water at 30°C of 0.2 mass% or less, a melting point, or when there is no melting point, a decomposition temperature of 150°C or more,
Artificial leather having a content ratio of the above-mentioned phosphorus flame retardant particles of 1 to 6 mass% in terms of phosphorus atoms. In paragraph 1,
The above polymer elastomer comprises polyurethane, which is a reaction product of a polyurethane raw material including a polymer polyol, an organic polyisocyanate, and a chain extender.
The above polymer polyol is a polycarbonate polyol in which at least 60 mass% is polycarbonate polyol, and further, the average repeating carbon number excluding the reactive functional group is 6.5 or less,
A synthetic leather having a raised texture, wherein the organic polyisocyanate comprises at least one selected from the group consisting of 4,4'-dicyclohexyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate. In paragraph 1,
Artificial leather with a surface weight of 100 to 300 g/㎡. In paragraph 1,
A synthetic leather having a content ratio of the phosphorus flame retardant particles in the total amount of the phosphorus flame retardant particles and the polymer elastomer, in terms of phosphorus atoms, of 5 to 20 mass%. In paragraph 1,
A synthetic leather having a content ratio of the phosphorus flame retardant particles in the total amount of the phosphorus flame retardant particles and the second polymer elastomer, in terms of phosphorus atoms, of 10 to 30 mass%. A composite material formed by bonding an inner lining material to the back surface of the artificial leather described in any one of claims 1 to 5 using an adhesive. In paragraph 6,
A composite material having a total calorific value (THR) of 10 MJ/㎡ or less. In paragraph 6,
Composite material having a maximum heating power (PHRR) of 250 kW/㎡ or less. In paragraph 6,
A composite material having a maximum average rate of heat dissipation (MARHE) of 90 kW/㎡ or less. delete delete delete delete delete