JP2003213575A - Method for producing leather-like sheet material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leather-like sheet material which satisfies physical properties such as strength, and has an excellent color-developing property, a graceful appearance, and excellent flexibility. <P>SOLUTION: This method for producing a leather-like sheet material comprising a polyurethane and a non-woven fabric comprising polyester fibers having a fineness of ≤0.5 dtex is characterized by immersing the non-woven fabric in an alkali aqueous solution, impregnating the treated non-woven fabric with a polyurethane solution, squeezing the fabric, and then drying off ≥10 wt.% of the solvent of the polyurethane solution. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a leather-like sheet material having good physical properties, flexibility and a soft texture, excellent color development and graceful quality.

[0002]

2. Description of the Related Art Nonwoven fabrics made of polyester fibers having a fineness of 0.5 dtex or less and leather-like sheet made of polyurethane are widely used for clothing and materials. In particular, a leather-like sheet material using ultrafine fibers of 0.5 dtex or less has a texture and touch similar to natural leather, and its use has been expanding in recent years.

As a method of applying polyurethane, a wet coagulation method in which a nonwoven fabric impregnated with a polyurethane solution and squeezed is immersed in water or a mixed solution of water and a solvent of polyurethane to replace the solvent of polyurethane is widely used. There is. According to this method, the polyurethane has a microporous structure and the product has a soft texture. When it is dyed in a dark color, it has a problem of so-called irritability that the surface polyurethane looks whitish and impairs the quality.

In contrast, a polyurethane solution is impregnated,
Although these drawbacks can be solved by using a dry coagulation method of directly drying the squeezed non-woven fabric and removing the solvent of polyurethane, there is a problem that the texture becomes hard because the adhesion between the polyurethane and the fiber is too strong. there were.

Several methods have been proposed to solve these problems. For example, as illustrated in JP-A-7-126986, a method of slicing a sheet composed of ultrafine fibers and an elastic polymer, coating the solution containing the solvent of the elastic polymer on the sliced surface, and performing dry coagulation, As illustrated in JP-A-61-32432, a sheet obtained by applying a polyurethane to a fibrous sheet by a wet coagulation method is further coated with a liquid which is a solvent of polyurethane and a non-solvent of fibers, so that a part of polyurethane is obtained. Although a method of dissolving / swelling is proposed, none has been obtained that satisfies all the sensitivities such as color developability and texture, and the physical properties such as tensile strength and tear strength.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a leather-like sheet material satisfying physical properties such as strength, having excellent color development and grace, and having excellent flexibility.

[0007]

The present invention employs the following means in order to solve the problems of the prior art.

That is, a method for producing a non-woven fabric made of polyester fiber having a fineness of 0.5 dtex or less and a leather-like sheet made of polyurethane, in which the non-woven fabric is immersed in an alkaline aqueous solution and then impregnated with a polyurethane solution and squeezed Then, 10% or more of the solvent of the polyurethane is dried and removed, and then substantially solidified, which is a method for producing a leather-like sheet.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The fineness referred to in the present invention is 0.5 dte.
The polyester fibers of x or less are those spun by ordinary wet, dry and melt spinning methods, and further, melt blow method, a method for extracting and removing one component from composite fibers such as sea-island type fibers and polymer blend fibers, and split yarn What is obtained by the method etc. can be used.

As the form of the ultrafine fiber-expressing type fiber which is a composite type fiber, a polymer mutual array fiber as shown in Japanese Patent Publication No. 48-22126 and Japanese Patent Publication No. 51-2104.
It is preferable to appropriately select and use the mixed spun fibers such as those disclosed in Japanese Patent Publication No. 1 and Japanese Patent Publication No. 60-21904, according to the purpose.

The component to be the ultrafine fibers of the ultrafine fiber-expressing fibers by the direct spinning method can be appropriately selected from polyesters such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate and copolymers thereof, but durability, Polyethylene terephthalate is preferred from the viewpoints of wet fastness, light fastness, and wrinkle resistance. Further, the component to be removed of the ultrafine fiber expressing type fiber is not particularly limited, but polypropylene, polystyrene, polyvinyl alcohol or the like is used to express the ultrafine fiber, and then the polyester fiber which is the ultrafine fiber is treated with an alkaline aqueous solution. There is a need.

Further, as the ultrafine fiber-expressing fiber, a composite fiber composed of polymer substances having different solubilities in an alkaline aqueous solution is preferable because the expression treatment of the ultrafine fiber and the treatment with the alkaline aqueous solution can be performed at the same time.

The fact that the polymeric substances have different solubilities in an alkaline aqueous solution means that they have the same surface area.
The dissolution rate in a 10% sodium hydroxide aqueous solution heated to 0 ° C. is 5 times or more, and the high-solubility high-molecular substance in an alkaline aqueous solution is stably and selectively dissolved.
It is more preferable that the difference is 0 times or more. Further, such a high-solubility polymer substance in an alkaline aqueous solution, that is, the component to be removed of the ultrafine fiber-expressing fiber is not particularly limited, but from the viewpoint of alkali dissolution rate and spinning stability,
A copolyester obtained by copolymerizing 5-sodium sulfoisophthalic acid, polyethylene glycol, sodium dodecylbenzenesulfonate, bisphenol A compound, isophthalic acid, adipic acid, dodecadioic acid, cyclohexylcarboxylic acid and the like is preferable. As the copolymerization ratio,
From the viewpoint of processing speed and stability, it is preferably 5 mol% or more, and is preferably 20 mol% or less because it is not dissolved in the stretching step and / or the shrinking step.

The non-woven fabric referred to in the present invention is not particularly limited as long as it is used for a normal leather-like sheet material, and in the dry method, an adhesive such as a dipping method, a printing method, a spray method, a powder method or an adhesive fiber method. Type, mechanical method such as felt method, stitch method, needle punch method, hydroentanglement method such as spunlace method, spunbond method, mesh method, melt blow method, spinning method such as film method, spunlace method in wet method It can be obtained by means of a hydroentangling method such as a method, a spinning method such as a flash spinning method, and a papermaking method such as a heat fusion fiber method, a hot pressing method, and an adhesive method. Moreover, you may combine these suitably. It is preferable that the non-woven fabric thus obtained is made of ultrafine fibers from the viewpoint of texture and quality.

The alkaline aqueous solution in which the nonwoven fabric made of polyester fibers is dipped is not particularly limited, but sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia salt and the like can be exemplified. A sodium hydroxide aqueous solution is preferable from the viewpoint of easy handling. The concentration and temperature at this time are not particularly limited, but when used in an ultrafine fiber expression treatment using a composite fiber composed of polymer substances having different solubilities in alkaline aqueous solution, the concentration and the treatment speed are high. Is in the range of 0.5 to 25%, and the temperature is 40 to
The range of 95 ° C is preferred. The fineness of ultrafine fibers obtained from such fibers is preferably 0.5 dtex or less from the viewpoint of the texture such as flexibility, but it is not always necessary that all the single fibers contained in the nonwoven fabric be 0.5 dtex or less. And the surface layer of the fibrous base material is substantially 0.5 dtex
It suffices that the following single fibers are formed. In the present invention, the single fiber fineness obtained by the above method is 0.5 dt.
A fibrous base material having a surface fiber layer mainly composed of ultrafine fibers of ex or less is applied. The single fiber fineness is 0.5 dt
When it is ex or less, the rigidity of the fiber is small and the nap of the surface nap is weak, so that it is possible to obtain a high-grade surface quality, a touch feeling, and a writing effect peculiar to the suede-like artificial leather.

In the present invention, a polymer substance having alkali dissolution resistance can be added as a reinforcing agent during the treatment of ultrafine fibers. The term "alkali dissolution resistance" as used herein means that the weight loss rate with respect to a 10% aqueous sodium hydroxide solution heated to 70 ° C is 10% or less. The polymer substance at this time is not particularly limited, and polyurethane, polyethylene, polyvinyl alcohol and the like can be selected, but polyvinyl alcohol having hot water solubility is preferable from the viewpoint of protecting the napped layer of the suede-like artificial leather.

The saponification degree is 9 from the viewpoint of reducing the solubility.
After applying 5% or more of polyvinyl alcohol, 80-
After heat treatment at 160 ° C., a sparingly soluble agent such as borax, boric acid, and sodium hydroxide can be appropriately used.

The polyurethane which can be used in the present invention is not particularly limited, but for example, at least one kind of polymer diol such as polyester polyol, polyether polyol, polycarbonate polyol, polymer diol such as polyester polycarbonate polyol, and an isocyanate group. Conventionally used, for example, aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, specifically,
Hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 3,3'- Dichloro-4,
At least one kind of 4'-diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate and the like and a low molecular weight compound having two or more active hydrogen groups capable of reacting with an isocyanate group as a chain extender in the molecule, for example, ethylene glycol, propylene glycol, 1,4-
Butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate, xylene glycol, 1,4-bis (Β-hydroxyethoxy) benzene and other diols, hydrazine, ethylenediamine, propylenediamine, isophoronediamine, piperazine and its derivatives, phenylenediamine, tolylenediamine, xylylenediamine, adipic acid dihydrazide, isophthalic acid dihydrazide, hexamethylenediamine,
At least one of diamines such as 4,4′-diaminophenylmethane and 4,4′-dicyclohexylmethanediamine, triamines such as diethylenetriamine, aminoalcohols such as aminoethyl alcohol and aminopropyl alcohol, and the like are prescribed. It is obtained by reacting in a molar ratio. This polyurethane can be used as a polyurethane solution dissolved in a solvent such as toluene, methyl ethyl ketone, N, N'-dimethylformamide, and isopropyl alcohol.

The concentration of these polyurethane solutions is preferably in the range of 1 to 40%, depending on the desired amount, texture, and physical properties of the leather-like sheet material, and the amount adhered to the non-woven sheet material is fiber to fiber. 2 to 140% by weight is preferable.

Alternatively, the applied non-woven sheet material is
In the case where the woven or knitted fabric itself has high strength properties, the concentration of the polyurethane solution is in the range of 1 to 30%, and the amount of the polyurethane attached to the nonwoven sheet is 2 based on the weight of the fiber. The range of -80% is preferable. That is, if the amount of polyurethane adhered to the non-woven sheet is less than 2%, the binder effect of polyurethane is significantly reduced, and the desired dimensional stability of the artificial leather cannot be obtained. It is not preferable because it has a rough texture.

In the present invention, the method of applying the polyurethane solution can be carried out by an impregnation method, a spray method, a coating method or the like. In consideration of workability and ease of pickup control, the impregnation method of squeezing with a mangle or the like is preferable.

In the method of coagulating polyurethane according to the present invention, it is essential to dry and remove 10% or more of the solvent of polyurethane, and then the polyurethane can be substantially solidified by a usual dry method or wet method. The dry method here means that gelation of polyurethane is performed by removing a solvent or a dispersion medium.

The wet method referred to here means that gelation of polyurethane is carried out by replacing the solvent with a non-solvent. The drying temperature for drying and removing 10% or more of the solvent of the polyurethane can be appropriately selected, but from the viewpoint of processing speed, it is 50 ° C or more, because it does not affect the dyeability and physical properties of the polyester fiber constituting the nonwoven fabric. It is preferably 180 ° C or lower. In this way, it is preferable to substantially solidify the polyurethane by a wet method after removing 10% or more of the polyurethane solvent from the viewpoint of softening the texture. Specifically, as described above, after 10% or more of the polyurethane solvent after squeezing is dried and removed at a drying temperature of 50 ° C. or higher and 180 ° C. or lower, it is added to water or a mixture of water and the polyurethane solvent. Immersion is preferred. Also,
In order to adjust the physical properties, texture, color development, and quality, the solvent of polyurethane may be removed almost completely by drying and the treatment may be carried out by a dry method in which the polyurethane is substantially solidified.
These can be appropriately selected depending on the desired texture and physical properties of the leather-like sheet material.

When polyvinyl alcohol is applied before applying polyurethane, the polyvinyl alcohol is extracted and removed with hot water using an open soaper, wince or the like. Here, the sheet can be half-cut in the thickness direction, but in this case, either the half-cut surface or the non-half-cut surface may be napped. Due to the effect, there is little polyurethane on the napped surface, and good quality is obtained, which is preferable. The leather-like sheet material excellent in nap quality can be obtained by subjecting the non-woven fabric made of polyester fiber and the sheet made of polyurethane thus obtained to nap raising treatment. The dyeing method is not particularly limited, but it is preferable to use a circular dyeing machine because the texture is softened by being rubbed by the liquid flow during the treatment.

In the present invention, the polyvinyl alcohol aqueous solution and the polyurethane solution may contain a small amount of various stabilizers such as light stabilizers, pigments, migration inhibitors and the like.

By the above-mentioned manufacturing method, a leather-like sheet material satisfying physical properties such as strength, excellent color development and elegant quality, and excellent in flexibility can be obtained. It is possible to further enhance the commercial value by applying finishing processing such as electric processing and water repellent processing.

[0027]

The present invention will be described with reference to the following examples. Parts in the examples refer to parts by weight. The dissolution rate, weight loss rate, tensile strength and tear strength in the present invention were measured by the following methods. (1) Dissolution rate According to the chemical resistance test of JIS K6911 method, it was determined from the weight ratio obtained by setting the treatment time to 1 hour. (2) Weight reduction rate W is obtained by impregnating 2 g of polypropylene non-woven fabric so that the total weight becomes about 5 g and applying.
₀ g, and this was kept at a liquid temperature of 70 ° C in a constant temperature bath 1
The weight after immersion in 300 mL of 0% by weight sodium hydroxide aqueous solution for 60 minutes was W ₁ g, and the weight was determined by the following equation. Weight reduction rate = (W ₀ −W ₁ ) / (W ₀ −2) × 100
(%) (3) Tensile strength Tensile strength measuring device (Tensilon manufactured by Toyo Instruments)
A sample with a width of 2 cm is used with a distance between chucks of 100 m
m 2 and a crosshead speed of 100 mm / min. (4) Tear strength Measured by the Elmendorf tear strength measurement method. Example 1 Polyethylene terephthalate copolymerized with 5.5 mol% of 5-sodium sulfoisophthalic acid was used as a sea component.
Part, island terephthalate as a component of 70 parts in a ratio of 1 filament and 36 islands in the inside, and using a staple of sea-island type fiber having an average fineness of 3.8 dtex, through a card or a cross wrapper Form a web, then apply needle punching,
A non-woven fabric was created.

The sheet has a degree of polymerization of 500 and a degree of saponification of 98%.
After 30% by weight of the polyvinyl alcohol aqueous solution was impregnated and applied to the island fibers, it was dried at 150 ° C. This sheet was treated with a 10% aqueous sodium hydroxide solution at 60 ° C. to which 1 g / L of borax was added to remove sea components. This sheet was impregnated with a 10% solution of polyester-based polyurethane using N, N-dimethylformamide as a solvent, and then the solvent of polyurethane was adjusted to 10 with a hot air dryer at 110 ° C.
Dry to 0% removal and add 30% polyester based polyurethane to polyethylene terephthalate in the sheet.
Wt% was added. Then, polyvinyl alcohol was extracted and removed with hot water.

Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

As shown in Table 1, the obtained leather-like sheet had an excellent color-forming property, a graceful napped quality, and a soft texture. Comparative Example 1 A sea-island type fiber having polystyrene having 30 parts as a sea component and polyethylene terephthalate as an island component of 70 parts at a ratio of 1 filament and 36 islands of the island component and having an average fineness of 3.8 dtex. A staple was used to form a web through a card and a cross wrapper, and then needle punching was performed to form a nonwoven fabric.

This sheet has a degree of polymerization of 500 and a degree of saponification of 98%.
After 30% by weight of the polyvinyl alcohol aqueous solution was impregnated and applied to the island fibers, it was dried at 150 ° C. This sheet was treated with trichlorethylene to remove sea components. This sheet is impregnated with a 10% solution of a polyester-based polyurethane using N, N-dimethylformamide as a solvent, and then dried by a hot air dryer at 110 ° C. until 100% of the solvent of the polyurethane is removed to form a polyester-based polyurethane sheet. 30% by weight was applied to the polyethylene terephthalate therein. Then, polyvinyl alcohol was extracted and removed with hot water.

Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

The leather-like sheet material thus obtained exhibited excellent coloring properties as shown in Table 1 and had a graceful napped quality.
It was paper-like and had a hard texture. Comparative Example 2 A sheet from which sea components were removed in the same manner as in Example 1 had N,
After impregnation with a 10% solution of polyester-based polyurethane using N-dimethylformamide as a solvent, the mixing ratio was 3
After sufficiently coagulating in 0/70 N, N-dimethylformamide / aqueous solution, it was dried with a hot air dryer at 110 ° C. Then, polyvinyl alcohol was extracted and removed with hot water. According to this method, the solvent of the polyurethane removed by drying was 0%.

Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

The leather-like sheet thus obtained had an elongation in size during dyeing, and was inferior in quality because the polyurethane was visible on the surface as shown in Table 1. The tensile strength was also weak. Example 2 A sea-island type fiber having 30 parts of polyethylene as the sea component and 70 parts of polyethylene terephthalate as the island component and 1 island of the filament component and 36 islands of the island component therein, and an average fineness of 3.8 dtex. A staple was used to form a web through a card and a cross wrapper, and then needle punching was performed to form a nonwoven fabric.

This sheet has a degree of polymerization of 500 and a degree of saponification of 98%.
After 30% by weight of the polyvinyl alcohol aqueous solution was impregnated and applied to the island fibers, it was dried at 150 ° C. This sheet was treated with toluene at 60 ° C. to remove sea components, and then treated with a 10% aqueous sodium hydroxide solution at 60 ° C. to which 1 g / L of borax was added. This sheet is impregnated with a 10% solution of a polyester-based polyurethane using N, N-dimethylformamide as a solvent, and then dried by a hot air dryer at 110 ° C. until 100% of the solvent of the polyurethane is removed to form a polyester-based polyurethane sheet. 30% by weight was applied to the polyethylene terephthalate therein. Then, polyvinyl alcohol was extracted and removed with hot water.

Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

As shown in Table 1, the obtained leather-like sheet had an excellent color-forming property, a graceful napped grade, and a soft texture. Comparative Example 3 A sheet obtained by removing sea components in the same manner as in Example 2 was
After impregnating a 10% solution of polyester-based polyurethane using N-dimethylformamide as a solvent, the polyester-based polyurethane is dried with a hot air dryer at 110 ° C. until 100% of the solvent of the polyurethane is removed, and the polyester-based polyurethane is added to the polyethylene terephthalate in the sheet. 30% by weight.
Then, polyvinyl alcohol was extracted and removed with hot water.
Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

The leather-like sheet thus obtained had an excellent coloring property as shown in Table 1 and had an elegant nap quality, but had a hard texture. Example 3 A sea-island type fiber having 30 parts of polyethylene as a sea component and 70 parts of polyethylene terephthalate as an island component is included in one filament and 36 islands of the island component, and an average fineness of 3.8 dtex. A staple was used to form a web through a card and a cross wrapper, and then needle punching was performed to form a nonwoven fabric.

This sheet has a degree of polymerization of 500 and a degree of saponification of 98%.
After 30% by weight of the polyvinyl alcohol aqueous solution was impregnated and applied to the island fibers, it was dried at 150 ° C. This sheet was treated with toluene at 60 ° C. to remove sea components, and then treated with a 10% aqueous sodium hydroxide solution at 60 ° C. to which 1 g / L of borax was added. This sheet was impregnated with an 8% solution of a polyester-based polyurethane using N, N-dimethylformamide as a solvent, dried with a hot air dryer at 110 ° C. until 40% of the solvent of the polyurethane was removed, and then coagulated in water. Then, it was dried with a hot air dryer at 110 ° C., and 20% by weight of the polyester-based polyurethane was applied to the polyethylene terephthalate in the sheet. Then, polyvinyl alcohol was extracted and removed with hot water.

Next, this sheet was sliced and buffed, and then dyed with a disperse dye in a circular dyeing machine.

As shown in Table 1, the obtained leather-like sheet had excellent color-forming properties, an excellent napped grade, and a soft texture.

[0043]

[Table 1]

[0044]

EFFECTS OF THE INVENTION According to the production method of the present invention, it is possible to produce a leather-like sheet material satisfying physical properties such as strength, excellent color development and grace, and excellent flexibility. it can.

Claims (4)

[Claims] 1. A method for producing a leather-like sheet material made of a non-woven fabric made of polyester fiber having a fineness of 0.5 dtex or less and a polyurethane, comprising impregnating the non-woven fabric with an alkaline aqueous solution, impregnating with a polyurethane solution, and squeezing liquid. After that, 10% by weight or more of the solvent of the polyurethane after squeezing is dried and removed, and a method for producing a leather-like sheet material. 2. The leather-like material according to claim 1, wherein the non-woven fabric is composed of composite fibers containing two or more kinds of polymer substances, and the ultrafine fibers are expressed by immersion treatment in an alkaline aqueous solution. A method for manufacturing a sheet material. 3. The method for producing a leather-like sheet material according to claim 1, wherein the nonwoven fabric is dipped in an aqueous alkaline solution after being applied with polyvinyl alcohol. 4. A non-woven fabric is dipped in an alkaline aqueous solution, impregnated with a polyurethane solution, squeezed, and 10% or more of the solvent of the polyurethane after the squeezing is heated to 50 ° C. or more 18
A method for producing a leather-like sheet, which comprises immersing it in water or a mixed solution of water and a solvent of polyurethane after being dried and removed at a drying temperature of 0 ° C. or less.