JPH01132885A - Production of flexible leathery sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a leather-like sheet that has a flexible texture and is excellent in hydrolysis resistance, mold resistance, light weather resistance, and bending resistance. It is something.

[Conventional technology].

BACKGROUND ART Conventionally, it has been known to contain and/or coat a fibrous substrate with a polymer mainly composed of polyurethane elastomer to form a leather-like sheet. In order to produce leather-like sheets, various additives have been proposed as coagulation regulators and pore structure regulators in the so-called wet coagulation method in which a polyurethane solution is treated and coagulated in a polyurethane non-solvent. , the applicant of the present application has already reported in 1973 that porous polyurethane can be produced by wet coagulation of a polyurethane solution to which higher alcohols such as stearyl alcohol, hydrocarbons, nonionic surfactants, organic carboxylic acids, etc. have been added as coagulation regulators. -22719 Publication, 42-27
Publication No. 269, Publication No. 45-39634, Publication No. 45-3
No. 9635, No. 46-2593, No. 47-3
No. 477, No. 47-5634, No. 47-30
No. 624, No. 4B-4940, No. 4g-49
Publication No. 41, Publication No. 48-5264, Publication No. 52-205
Publication No. 22, Publication No. 54-21401, Publication No. 55-23
The proposal was made in Publications No. 954 and No. 56-41652. Furthermore, the addition of an ethylene oxide adduct was proposed in Japanese Patent Publication No. 55-47055. Also,
Although not added to a polyurethane solution, a method has also been proposed in which a fiber sheet is treated with a water-soluble silicone oil, then impregnated with a polyurethane solution, and wet-coagulated.

[Problems to be solved by the invention] Various additives are added to the conventional polyurethane solution to adjust the coagulation rate of the polyurethane and the pore structure formed by wet coagulation. It has been used to adjust the cell structure of porous polyurethane and the apparent density of polyurethane layers.

However, if conventional additives or compositions based on these additives are applied to hydrophobic polyurethane and wet coagulation is performed, the cell structure of porous polyurethane can be adjusted to a certain extent. However, the resulting porous polyurethane structure is easily deformed by compression effects such as embossing, or when it is manufactured into a product through secondary processing, such as a process of treatment with aromatic hydrocarbons or halogenated hydrocarbons. These processing agents collapse or deform the cell structure, changing the porous polyurethane structure, making it impossible to obtain a leather-like sheet with good appearance and texture.

As a result of investigating the cause, we found that with conventional additives, hydrophobic polyurethanes, especially hydrophobic polyurethanes with a white oil value of 13 or less, can produce durable and stable cell membranes even when the combination of additives and coagulation conditions is changed. It turned out that it was not.

The present invention is to produce a porous polyurethane structure having a stable porous structure using a wet coagulation method of a hydrophobic polyurethane solution. In particular, the object is to obtain a polyurethane porous structure with a stable structure in the production of leather-like sheets.

[Means for Solving the Problems] The present invention impregnates and/or coats a fiber sheet with a polymer solution mainly composed of polyurethane, and coagulates it with a non-solvent to produce a porous structure. At least one soft segment selected from polytetramethylene ether, polypropylene ether, polycaprolactone, polyvalerolactone, polyβ-methyl-δ-valerolactone, and polyhexamethylene adipate with an average molecular weight of 600 to 3000. In a polymer solution mainly composed of hydrophobic polyurethane,
It is characterized by using a liquid composition to which at least one selected from a higher alcohol having 8 or more carbon atoms, alcohol-modified silicone oil, polyoxyethylene alkylphenyl ether, and sorbitan di- or tri-substituted fatty acid ester is added as a coagulation regulator. This is a method for producing flexible leather-like sheets.

That is, the polyurethane applied in the present invention has an average molecular weight of 160 as the soft segment constituting the polyurethane.
0-3000 polytetramethylene ether diol,
Polypropylene ether glycol, polyhexamethylene adipate glycol, polycaprolactone diol, polyvalerolactone diol, poly(β-methyl-δ
- valerolactone) at least one diol selected from
35-70% by weight, preferably 45-65% by weight of various polymeric diols and organic diisocyanates, e.g.
．． Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated quinlylene diisocyanate, etc. at least one selected from aliphatic or alicyclic diisocyanates, etc., and a compound having a molecular weight of 300 or less and having two active hydrogen atoms as a chain extender, such as ethylene glycol, propylene glycol, butanediol, hexanediol, 3- Diols such as methylpentanediol-1.5.1.4-cyclohexanediol and xylene glycol; diamines such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, tolylenediamine, and isophoronediamine , hydrazine, adipic acid dihydrazide, isophthalic acid dihydrazide, etc., or at least one selected from hydrazides, etc., in a desired ratio. Polyurethane was dissolved in dimethylformamide solvent at 10% by weight.
A polyurethane polymerized with a solution having a solution viscosity of at least 1 void, preferably 2 to 10 voids when measured at a temperature of 30 DEG C. is used. If the solution viscosity is low, it may not be possible to obtain a sponge structure with sufficient strength, or the bending fatigue resistance may not be sufficient. On the other hand, if the solution viscosity is too high, not only will processability deteriorate, but it will also become difficult to control coagulation to obtain a spongy structure with good uniformity. Further, other polymers may be mixed with the polyurethane at a mixing ratio of 40% by weight or less. For example, other types of polyurethanes or polymers that share a common solvent. A particularly preferred polymer is polyethylene ether polyurethane, which is polymerized using polyethylene ether glycol as a diol component.
In particular, when coagulating in a coagulating solution containing water, it not only enables uniform coagulation, but also improves the dyeability of polyurethane and provides a soft texture as a leather-like sheet.
A product with a moist texture can be obtained. Furthermore, the additive of the present invention is effective for polyurethanes having a white oil value of 13 or less, as expressed by the white oil value of the hydrophobicity of the polyurethane. With highly hydrophilic polyurethane, it is easy to obtain a porous polyurethane structure with a stable sponge structure without using a special coagulation regulator.

In addition, as additives to form a stable porous polyurethane structure by adding it to the polyurethane-based solution of the present invention, higher alcohols having 8 or more carbon atoms, such as octatool, nonanol, decyl alcohol, At least one higher alcohol such as decyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, oleyl alcohol, ceryl alcohol, myricyl alcohol, and sorbitane or tridecyl alcohol. Fatty acid esters, such as sorbitan, are combined with higher carboxylic acids such as lauric acid, stearic acid, oleic acid, and palmitic acid.
Alcohol-modified silicone oils such as diesters or triesters obtained by reacting molecules or three molecules have the general formula R1 of ■ or -CI' [3, R5 is an alkyl group, n
is an integer of 10 to 35 and an average molecular weight of 850 to 3,500) alcohol-modified silicone oil, a polyoxyethylene alkyl phenyl ether represented by a general formula of an alkyl group having 5 to 10 carbon atoms, n is an integer of 2 to 20) It is a blend with at least one selected type. For example, high-grade colcol and alcohol-denatured silicone oil,
A preferred composition is a combination of a higher alcohol and a polyoxyethylene alkylphenyl ether, a higher alcohol, an alcohol-modified silicone oil, and a polyoxyethylene alkylphenyl ether, a higher alcohol, an alcohol-modified silicone oil, and a sorbitan di- or tri-substituted fatty acid ester. The product is a combination of higher alcohol and alcohol-modified silicone oil or higher alcohol and alcohol-modified silicone oil and other additives.

The amount of additives added is 0.3 to 30% by weight of the higher alcohol based on the polyurethane, and 0.2 to 35% by weight of other additives based on the polyurethane. It ranges from 0.5 to 50% by weight. The composition of additives for polyurethane and the amount of additive composition added are determined by the structure of polyurethane, solution viscosity (degree of polymerization, degree of branching, etc.), solution concentration, coagulation conditions, desired sponge structure, hydrophobicity of polyurethane, etc. . For example, even if the polyurethane is the same (polyurethane composition, solution viscosity, and hydrophobicity are the same), the concentration of the polyurethane solution used, the coagulation conditions of the polyurethane solution, the desired sponge structure, such as a fine spherical structure, a fine longitudinal structure, etc. The amount of additives to be added and the amount of additive composition to be added are determined depending on whether the pore shape is to be defined, such as a giant honeycomb structure. If the amount added is small, a good sponge structure or a porous sponge structure with uniformity will not be obtained. In addition, if the amount added is too large, the membrane between the sponges becomes thin or becomes too microporous, resulting in a decrease in mechanical strength and swelling resistance, which is not preferable. Furthermore, in order to effectively perform the coagulation regulating effect of the additive or additive composition, it is necessary to add 0.05 to 3.0% by weight of the polyurethane composition.
It is preferable to add water or a lower alcohol having 4 or less carbon atoms. If the amount added is small, the effect will be small, but if the amount added is too large, it will cause non-uniform coagulation. Coagulate with a combined non-solvent or solvent-non-solvent coagulating liquid. Since the temperature of the coagulating liquid affects the sponge structure to be formed, conditions for forming the desired sponge structure are set.

That is, if the temperature of the coagulation bath is high, the entire material will solidify slowly, resulting in a fine and uniform sponge structure.

On the other hand, if the coagulation bath temperature is low, a dense skin layer is formed on the surface, and the interior solidifies slowly, forming a huge uniform sponge structure. In order to form such a preferable sponge structure, the coagulation bath temperature may be selected within the range of 20 to 60°C. Furthermore, if the concentration of the solvent in the coagulation liquid becomes high, the coagulation becomes slow, so the solvent concentration is set to 60% or less. The sheet material obtained by coagulation is washed with water and dried to obtain a base sheet. Additionally, additives may be removed during the process up to the final product, but
If necessary, leaving it on may have a favorable effect on softening the texture.

Furthermore, the fiber sheet used to produce the leather-like sheet of the present invention is a fiber of at least 1N11 selected from natural fibers, regenerated fibers, and synthetic fibers, preferably polyester, polyamide, polyolefin, polyacrylonitrile, polyurethane, or polyurethane urea. These are staple fibers or filament fibers of a single component obtained by spinning a polymer such as polyvinyl chloride (including irregular cross-section yarns and fine-grained yarns obtained by spinning or drawing methods). Even more preferable fibers are multicomponent fibers obtained by selecting at least two polymers having different physical or chemical properties and spinning them using a conventionally known spinning method, or at least one of the above polymers and another polymer. , e.g. polystyrene,
At least ti polymers selected from polyacrylates, copolymers of acrylic esters or methacrylic esters, polyvinyl alcohol, polyvinyl acetate or vinyl acetate copolymers, and other polymers that can be spun together with the utilized fiber components are spun using conventional methods. A fiber structure is made from staple fibers or filament fibers of multicomponent fibers obtained by spinning the multicomponent fibers, and then the multicomponent fibers are modified by a method of removing one component of the multicomponent fibers or a method of dividing and separating them. It is made into ultrafine fibers or ultrafine fiber bundles. These fibers are woven fabrics, napped knitted woven fabrics, fiber entangled nonwoven fabrics, and fiber sheets.

Next, when the surface of the base sheet obtained in the present invention is formed of a porous layer of a polymer mainly composed of polyurethane, a resin containing a coloring agent is applied to the surface of the porous layer.
Finishing treatments such as embossing, softening treatment, and dyeing are combined to obtain a leather-like sheet with silver.

In addition, if the base material seed is simply a fibrous base material impregnated with a polymer mainly composed of polyurethane, the base material sheet may be sliced to the desired thickness in the thickness direction as necessary. At least one side of the material sheet is brushed,
A coloring treatment and a softening treatment are performed to obtain a suede-like leather-like sheet with raised fibers on the surface.

The leather-like sheet obtained by the present invention has a stable sponge structure, has a texture with excellent flexibility and drapability, and has excellent bending resistance, mold resistance, and hydrolysis resistance. In addition, the silvered leather-like sheet has a good appearance and texture, such as folding and wrinkle formation, and smoothness, and the suede-like sheet has good raised properties, and furthermore, &11i!
l! It has excellent workability, cutting workability, plowing and embossing properties.

[Example] Next, embodiments of the present invention will be explained with specific examples. Note that parts and percentages in the examples are by weight unless otherwise specified.

The white oil value of polyurethane in the examples was measured by keeping 50 g of a dimethylformamide (hereinafter abbreviated as DMF) solution with a polyurethane concentration of 5% and keeping it at 50°C, and adding 1% DMF/water while stirring with a magnetic cooler. /1 mixed solution was added dropwise using a biuret, and the amount of the polyurethane solution turned into a white oil was expressed as the amount of the drop (CC number).

Example 1 Polytetramethylene ether glycol (hereinafter abbreviated as PTMG) with an average molecular weight of 1 tioo 1101.4.
4'-diphenylmethane diisocyanate (hereinafter referred to as MDI)
) 75 parts and 18 parts of 1,4-butanediol
[Nitrogen content based on isocyanate groups: 4.1%, hard segment! (calculated value>
45.8%, polyurethane concentration 10%, DMF solution viscosity 3.5 voices, white oil value 6.1] (this is referred to as polyurethane-A) was used to create an entangled nonwoven fabric of multicomponent fibers consisting of 6-nylon and polyethylene. The impregnating composition liquid to be impregnated into the surface and the coating composition liquid to be applied to the surface were prepared with the compositions shown in Table 1.

Next, a multi-component fiber-entangled nonwoven fabric with a basis weight of 480 g/e" was impregnated with a 5% polyurethane-AI impregnated composition, the surface was leveled, and a 13% polyurethane-A coating composition was applied on top of it with a polyurethane amount of 80 g/e. Apply the amount of liquid equivalent to 800ml and DM
F immersed in a 50% aqueous solution to coagulate, washed with water, then treated in hot toluene to elute the polyethylene component in the Ia vertebrae, washed and dried to form a Kyoku JIII fiber bundle entangled nonwoven fabric containing polyurethane. A base material sheet was obtained in which the grown fiber sheet substrate and a porous polyurethane coating surface layer was provided on one side thereof. A polyurethane finish containing black pigment was applied to the surface layer of this base sheet, and a leather-like surface was embossed by heat embossing, followed by further finishing treatment to obtain a leather-like sheet.

Summary of the evaluation of polyurethane additives and their effects on this leather-like sheet. On the other hand, the sponge structure of the comparison product was unstable, with partial dents and small wrinkles appearing all over the surface.

(2) Comparing the texture and surface crease shape of the finished leather-like sheets, the example sheet was flexible and had good drapability, but also had many fine and long creases, giving it a softer appearance and a heavier feel. On the other hand, the same product for comparison had a slightly more resilient feeling, had poor drape properties and lacked a mellow feel, and the creases were shaped like hoki creases, giving the impression of hardness. there were.

Example 2 The following various polyurethanes were polymerized using a solution polymerization method.

(Polyurethane-B) 110 parts of PTM G with an average molecular weight of 1100, MD
Polyurethane obtained by reacting 100 parts of I and 27 parts of 1,4-butanediol [nitrogen content based on isocyanate groups 49%, hard segment content 55.9%, white oil value 1
0.3].

(Polyurethane-〇) (for comparative example) 110 parts of PTM G with an average molecular weight of 1100, MD
Polyurethane obtained by reacting 1,150 parts of 1,4-butanediol and 45 parts of 1,4-butanediol [nitrogen content based on isocyanate groups 5.6%, hard segment 1166.1%, white oil value 13.5].

(Polyurethane-D) Polyurethane obtained by reacting 145 parts of polycaprolactone diol (hereinafter abbreviated as PCL) having an average molecular weight of 1450, 50 parts of MDI, and 9 parts of 1,4-butanediol [nitrogen content based on isocyanate groups: 3. 1%, hard segment amount 33.0%, white oil value 9.1].

(Polyurethane-E) One average molecule j11450 no P CI, 145 parts, MD
Polyurethane obtained by reacting 75 parts of I and 18 parts of 1,4-butanediol [nitrogen content based on isocyanate groups 3.5%, hard segment Jt 39.1%, white oil value 10.8].

(Polyurethane-F) Average molecular weight 1450f7) P CL 145 parts, MD
Polyurethane obtained by reacting 100 parts of I and 27 parts of 1,4-butanediol [4.1% nitrogen content based on isocyanate groups, hard segment! 46.7%, white oil value 12.2.

(Polyurethane-G) (for comparative example) P CL 145 parts with average molecular weight 11450, MD 112
The following polyurethane composition liquid was prepared using the polyurethanes B to -0 obtained by reacting 5 parts of 1.4-butanediol and 36 parts of 1,4-butanediol, and the liquid amount of the polyurethane composition liquid was spread on a polyester film in an amount of approximately Apply an amount of 665g10+1 and solidify by immersing it in a 40% DMF aqueous solution.
A porous polyurethane sheet was obtained by washing with hot water and drying.

Table 2 shows the apparent density and surface smoothness of the porous polyurethane sheet.

(Polyurethane composition liquid-■) 15 parts of polyurethane, 0.8 parts of lauryl alcohol, 1.2 parts of oleyl alcohol, 2.0 parts of alcohol-modified silicone oil with an average molecular weight of 113,100, 0.5 parts of titanium oxide
1 part, and 80.5 parts of DMF.
A composition solution of 4.7 voids/30°C was prepared.

(Polyurethane composition liquid-II) (For comparative example) 15 parts of polyurethane, 0.8 parts of lauryl alcohol, 1.2 parts of oleyl alcohol, 0.5 parts of titanium oxide, and D M F
Solution viscosity 15.2 poise/30°C consisting of 82.5 parts
A composition solution was prepared.

In other words, even with hydrophobic polyurethane containing the additive composition of the present invention, a porous polyurethane sheet with a low apparent density and a stable sponge structure can be produced.

This porous polyurethane sheet can be made into a flexible leather-like sheet by adhering it to a fabric and applying a surface finish.

Implementation P43 As a polymer glycol with an average molecular weight of 2000, polytetramethylene ether glycol/polyethylene ether glycol/polyethylene adipate glycol (
200 parts of mixed diol (mixing ratio 5/2/3), MD1
Polyurethane obtained by polymerizing 138 parts of 1,4-butanediol and 40 parts of 1,4-butanediol by a solution polymerization method [nitrogen content based on isocyanate groups 4.1%, hard segment content 47.1%
, white oil value 12.8], 15 parts of polyurethane, 1.5 parts of cetyl alcohol, 2 parts of alcohol-modified silicone oil with an average molecular weight of 3000, 0.5 part of titanium oxide, and 81 parts of DMF'. A liquid was prepared (referred to as polyurethane composition liquid -■).

Next, a single-sided fiber napped woven fabric woven using nylon fibers was impregnated with the above polyurethane composition liquid -■, and after removing the excess liquid, it was immersed in a coagulation liquid containing a 50% DMF aqueous solution at a temperature of 28°C. solidify, wash with methanol, wash with hot water,
It was dried to obtain a sheet-like product. The fiber napped surface of this sheet was puffed with sandpaper, and after dyeing, a composition solution containing an anti-yellowing agent and a surface texture improver was applied to the napped surface by spraying.

This product had a uniform and stable sponge structure, yielded a suede-like sheet with a flexible texture, and was excellent in durability and surface strength.

For comparison, a polyurethane composition liquid - without addition of alcohol-modified silicone oil was prepared and impregnated into a fiber napped fabric in the same manner as in Example 3 to obtain a suede-like sheet. In this product, uneven coagulation occurred, and the sponge structure was not homogeneous (and a good suede appearance could not be obtained.Furthermore, due to the unevenness of the sponge structure, color unevenness due to dyeing was noticeable).

Example 4 PCL with average molecular weight 1450 and average molecular weight It 1100
Pseu TMG (mixing ratio 1/1) 127.5÷÷4, M D
Polyurethane obtained by polymerizing 112.5 parts of I and 21.7 parts of ethylene glycol by a solution polymerization method [nitrogen content based on isocyanate groups 4.8%, hard segment content 51
．． 3%, white oil 1a1i10.2], 12 parts of polyurethane, 2 parts of stearyl alcohol, 1 part of sorbitan tristearate, 1 part of carbon black and D M
A composition liquid consisting of 84 parts of F was prepared (referred to as polyurethane composition liquid -■).

Next, an entangled nonwoven fabric of sea-island structure multicomponent fibers consisting of polyethylene terephthalate (island component) and polyethylene was impregnated with the above polyurethane composition liquid -■, and after removing the excess adhering liquid, it was placed in a 20% DMF aqueous solution at a temperature of 40°C. The fibers are dipped in water to coagulate, then treated in hot tetrachloroethane to extract and remove the polyethylene in the fibers, washed with water, treated with a softener, and dried to form a polar a+ fiber bundle entangled nonwoven fabric containing porous polyurethane. A sheet-like product was obtained.

This sheet-like material is highly flexible, and is a suede-like sheet obtained by making the sheet-like material 0.13 mm thick, puffing the surface with sandpaper, and performing finishing treatments such as dyeing, softening treatment, and brushing. The material was a sheep-like leather-like sheet that was flexible and had excellent drapability, making it a material suitable for clothing.

Further, the sheet-like material is made to have a thickness of 0.8 am, the surface is smoothed by calendering, and an easily dyed polyurethane composition containing a coloring agent is applied to the surface by a gravure method, and dried to form pore-like holes. A silver-finished leather-like sheet with a sheepskin-like pattern formed on the surface by embossing was obtained. This product had excellent folding and drapability and was suitable for clothing.

[Effects of the Invention] By adding the additive composition of the present invention to a hydrophobic polyurethane solution, a porous polyurethane sheet with a homogeneous and stable sponge structure can be obtained, which is particularly useful in the production of leather-like sheets, with flexibility and drapeability. It has excellent texture and has many long, fine wrinkles similar to natural leather, giving it a solid and flexible appearance. In particular, a good sponge structure is formed even in flexible polyurethane containing many hydrophobic soft segments.

Furthermore, the resulting polyurethane can provide products with excellent hydrolysis resistance, mold resistance, and bending resistance.

Patent applicant RiRashi Co., Ltd.

Claims (3)

[Claims] (1) When manufacturing a porous structure by impregnating and/or coating a fiber sheet with a polymer solution mainly composed of polyurethane and coagulating it with a non-solvent, the soft segment constituting the polyurethane has an average molecular weight of 600 to 3000. A polymer mainly composed of hydrophobic polyurethane consisting of at least one kind of soft segment selected from polytetramethylene ether, polypropylene ether, polycaprolactone, polyvalerolactone, polyβ-methyl-δ-valerolactone, and polyhexamethylene adipate. Use a liquid composition in which at least one selected from a higher alcohol having 8 or more carbon atoms, alcohol-modified silicone oil, polyoxyethylene alkylphenyl ether, and sorbitan di- or tri-substituted fatty acid ester is added as a coagulation regulator. A method for producing a flexible leather-like sheet characterized by: (2) The method for producing a flexible leather-like sheet according to claim 1, wherein the hydrophobic polyurethane has a white number of 13 or less. (3) Coagulation regulator is higher alcohol and average molecular weight 850
The method for producing a flexible leather-like sheet according to claim 1 or 2, wherein the composition is an alcohol-modified silicone oil having an alcohol-modified silicone oil of 1 to 3,500% alcohol.