JP2004100051A - Method for producing leathery sheetlike material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leathery sheetlike material having excellent pilling resistance. <P>SOLUTION: The leathery sheetlike material composed of a fiber substrate consisting essentially of ultrafine fibers and a polyurethane resin is produced. In the process, the method for producing the leathery sheetlike material comprises the following four steps. (1) A step of producing the fiber substrate using ultrafine fiber developing type conjugated fibers developing the ultrafine fibers, (2) a step of developing the ultrafine fibers, (3) a step of applying the polyurethane resin to the fiber substrate and (4) a step of applying a polymeric ultraviolet light absorber after the step (3). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a leather-like sheet. More specifically, the present invention relates to a method for producing a leather-like sheet having excellent pilling resistance.
[0002]
[Prior art]
As artificial leathers having good nap and excellent flexibility and quality, which are not inferior to natural leathers, those using ultrafine fibers are known. The manufacturing method is as follows, for example. First, a felt is formed from fibers using a microfiber forming component as one component and a component soluble in an organic solvent or the like as another component. Next, a polyurethane resin diluted with an organic solvent such as dimethylformamide is applied to the felt to form a sheet. After that, one component of the conjugate fiber is dissolved and removed with an organic solvent to express ultrafine fibers, or the ultrafine fibers are removed from the fiber substrate. After expression, artificial leather is obtained by applying a polyurethane resin.
[0003]
However, in the artificial leather as described above, the occurrence of pilling due to a decrease in the force for binding the fiber has been a problem.
[0004]
Since light deterioration is considered as one of the causes of pilling, a technique of copolymerizing a solution-type polyurethane resin or a water-dispersion-type polyurethane resin with a hindered amine-based ultraviolet absorber has been disclosed to improve this. (See Patent Documents 1 to 4). However, a sufficient improvement effect was not obtained.
[0005]
[Patent Document 1]
JP-A-56-43478 [0006]
[Patent Document 2]
Japanese Patent Publication No. 63-31490
[Patent Document 3]
Japanese Patent Application Laid-Open No. 4-258642
[Patent Document 4]
JP 2000-265052 A
[Problems to be solved by the invention]
An object of the present invention is to provide a leather-like sheet having excellent pilling resistance.
[0010]
[Means for Solving the Problems]
That is, the present invention is a method for producing a leather-like sheet material comprising the following four steps in producing a leather-like sheet material mainly comprising a fiber base having ultrafine fibers and a polyurethane resin.
(1) A step of producing a fiber substrate using an ultrafine fiber-expressing conjugate fiber that expresses an ultrafine fiber.
(2) A step of developing ultrafine fibers.
(3) A step of applying a polyurethane resin to the fiber substrate.
(4) A step of applying a high-molecular ultraviolet absorber after the step (3).
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. In the present invention, the fabric at the stage before the polyurethane resin is applied, or the fabric obtained by removing the polyurethane resin or the like from the sheet when expressing the weight ratio of the constituent elements, is mainly referred to as a "fiber substrate", and the polyurethane resin is applied. The state is mainly called a “sheet”.
[0012]
The ultrafine fiber-expressing conjugate fiber referred to in the present invention is composed of a component constituting the ultrafine fiber and another component. The other component is dissolved by an organic solvent or an alkaline solution, and the remaining component forms the ultrafine fiber. Examples of the form of the ultrafine fiber-expressing composite fiber include, for example, a sea-island type in which a component having solubility in an organic solvent or an alkaline solution in the sea portion and a component constituting the ultrafine fiber in the island portion, a nebula type, a multilayer type, It is based on a hollow island type, etc., and is a combination of these, or a deformed one, and can be appropriately selected from those from which ultrafine fibers of preferably 0.3 dtex or less can be obtained by removing one component. It is.
[0013]
As the components forming the ultrafine fibers, polyesters such as polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate, polyamides such as nylon-6, nylon-6,6 and the like can be used.
[0014]
Examples of the organic solvent-soluble component include polyolefins such as polyethylene and polystyrene.
[0015]
Examples of the alkali-soluble component include, for example, polyethylene terephthalate and polybutylene terephthalate, 5-sodium sulfoisophthalic acid, polyethylene glycol, sodium dodenylbenzenesulfonate, bisphenol A compounds, isophthalic acid, adipic acid, and dodecadionic acid. And a copolymerized polyester obtained by copolymerizing cyclohexylcarboxylic acid and the like in an amount of 5 to 20 mol%. Among these, it is particularly preferable to use copolymerized polyethylene terephthalate obtained by copolymerizing 5-sodium sulfoisophthalic acid at 5 to 20 mol%. These copolymers may be not only binary but also multi-component copolymers of three or more.
[0016]
(1) In the present invention, a fiber substrate is manufactured using the ultrafine fiber-expressing conjugate fiber. As a form of the fiber substrate, a nonwoven fabric, a woven fabric, a knitted fabric, or the like can be adopted, but a nonwoven fabric is preferable in terms of a feeling. As a means for forming the nonwoven fabric, for example, a method of laminating fibers by a cross wrapper to form a nonwoven fabric, a method of directly forming a nonwoven fabric by direct spinning such as a spun bond method, a melt blow method, and a flash spinning method can be used.
[0017]
After forming the fabric such as a non-woven fabric, a felt may be formed by performing a fiber entanglement process such as a needle punch and a water jet punch as necessary.
[0018]
In addition, prior to the expression treatment of the ultrafine fibers described below, a high-saponification degree polyvinyl alcohol, a hot water-soluble polymer such as carboxymethyl cellulose may be previously applied to the fiber substrate for the purpose of controlling the bond between the polyurethane resin and the fibers. preferable.
[0019]
(2) In the present invention, the fiber substrate thus obtained is treated with an organic solvent, an alkaline aqueous solution, or the like, so that ultrafine fibers are developed. Examples of the organic solvent include toluene and trichloroethylene. Examples of the alkaline aqueous solution include a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, and an ammonium salt aqueous solution.
[0020]
(3) In the present invention, a polyurethane resin is applied to a fiber substrate expressing ultrafine fibers.
[0021]
As the chemical composition of the polyurethane resin used in the present invention, basically any one can be used, but a polyurethane resin obtained by reacting a polyol component, a diisocyanate and a chain extender by appropriately combining each component is used. Is preferred.
[0022]
As the polyol component, polyether diol, polyester diol, polycarbonate diol and the like can be employed. Among them, an ether-based polyurethane resin containing a polyether diol as a polyol component is excellent in hydrolysis resistance but has a problem in light resistance. Obtainable.
[0023]
These polyol components may be used alone or in combination as a copolymer.
[0024]
Examples of the polyether diol include polytetramethylene glycol, polypropylene glycol, polyethylene propylene glycol, polyoxytetramethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, and the like.
[0025]
Examples of the polyester diol include polyneopentyl adipate, polycaprolactone, and the like.
[0026]
Examples of the polycarbonate diol include compounds obtained by reacting glycols such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and diethylene glycol with dimethyl carbonate, diphenyl carbonate, and phosgene. Can be
[0027]
Examples of the diisocyanate component include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 3,3-dimethoxy-4,4-phenylene isocyanate.
[0028]
Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, ethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane and the like. These may be used alone or in combination of two or more.
[0029]
The polyurethane resin used in the present invention may be of a solution type when applied to the fiber substrate, but the use of an organic solvent is minimized in order to consider the environment and simplify the recovery process. From this, it is more preferable to use an emulsion type.
[0030]
The emulsion may be either a forced emulsification type or a self-emulsification type. In the case of the forced emulsification type, the nonionic surfactant shown below is contained in a proportion of 1 to 10 parts by weight based on 100 parts by weight of the polyurethane resin. Is preferred. When the nonionic surfactant is 1 part by weight or more, even when the emulsion is stored for a long period of time, there is no generation of creamy precipitates or non-redispersible coagulates due to phase separation from the emulsion and storage stability. The performance is improved. When the amount of the nonionic surfactant is 10 parts by weight or less, the sensitivity of heat-sensitive gelation is improved, and the time required for gelation by heating can be shortened.
[0031]
The nonionic surfactant used in the emulsion type polyurethane resin is a surfactant having a hydroxyl group or a polyether unit which is not ionically dissociated in water as a hydrophilic group, and includes a polyethylene glycol type nonionic surfactant. . As a polyethylene glycol type nonionic surfactant,
Higher alcohol ethylene oxide adducts such as polyoxyethylene lauryl ether, polyoxyethylene acetyl ether, and polyoxyethylene stearyl ether;
Fatty acid polyethylene oxide ester,
Examples include polyhydric alcohol fatty acid ester ethylene oxide adducts.
[0032]
Other resins may be used in combination with the emulsion type polyurethane resin as long as the thermosensitive gelling property and the storage stability are maintained. Examples of resins that can be used in combination include natural rubber, acrylonitrile-butadiene copolymer, and polybutadiene. One of these resins may be selected and used in combination with the emulsion polyurethane resin, or a plurality of these resins may be used in combination with the emulsion polyurethane resin.
[0033]
If necessary, a conventional ultraviolet absorber, an antioxidant, a coloring agent, a cross-linking agent, etc., of which specific examples will be described later, may be added.
[0034]
In addition, an inorganic salt, a thickener, or the like may be added in order to suppress the occurrence of uneven distribution of the resin inside the sheet during the solidification of the resin described below.
[0035]
In applying the emulsion type polyurethane resin to the fiber base, the fiber base is impregnated with the diluted emulsion and solidified. Coagulation methods include dry heat coagulation, wet heat coagulation, and heat drying, immersion in a bath in which an inorganic salt is dissolved or hot water bath, and coagulation of these methods. Etc. Further, in order to further improve water resistance and dyeing resistance, the sheet is heat-treated at 90 to 200 ° C., preferably 1 to 60 minutes, more preferably 120 to 150 ° C. for about 2 to 20 minutes as a heat treatment after solidification. Good.
[0036]
In applying the solution type polyurethane resin to the fiber substrate, it is preferable that the fiber substrate is impregnated with a solution of the polyurethane resin, then wet coagulated, and then dried.
[0037]
The amount of the polyurethane resin to be applied is preferably 5 to 150 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of the fiber base. By setting the applied amount to 5 parts by weight or more, more preferably 10 parts by weight or more, the sheet-like material is provided with a sense of fulfillment and the leather-like texture is improved. On the other hand, when the applied amount is 150 parts by weight or less, more preferably 100 parts by weight or less, the sheet-like material becomes flexible, and the leather-like texture is improved.
[0038]
(4) In the present invention, after the step (3), it is important to add a polymer ultraviolet absorber.
[0039]
By doing so, the pilling resistance of the sheet material can be improved. The mechanism has not yet been confirmed, but with the conventional means of applying an ultraviolet absorber, addition with a powder causes the ultraviolet absorber to fall off, and copolymerization with the polyurethane resin cannot cover the polyurethane resin at the molecular level. On the other hand, in the present invention, it is presumed that the ultraviolet absorbent layer is formed on the surface of the polyurethane resin layer after the polyurethane resin layer is formed, so that the polyurethane resin layer can be entirely protected.
[0040]
The molecular weight of the high-molecular ultraviolet absorber is preferably 10,000 to 500,000.
[0041]
As the polymeric ultraviolet absorber used in the present invention, for example, those containing at least one selected from a 2-hydroxybenzophenone derivative and a 2-hydroxybenzotriazole derivative as a component of the polymer are preferable.
[0042]
Examples of the 2-hydroxybenzophenone derivative include 2-hydroxy-4-acryloyloxybenzophenone, 2-hydroxy-4-methacryloyloxybenzophenone, 2-hydroxy-4- (2-acryloyloxy) ethoxybenzophenone, and 2-hydroxy-4- (Methacryloyloxy) ethoxybenzophenone, 2-hydroxy-4- (2-methyl-2-acryloyloxy) ethoxybenzophenone, and the like.
[0043]
Examples of the 2-hydroxybenzotriazole derivative include 2- [2′-hydroxy-5 ′-(methacryloyloxy) phenyl] benzotriazole, 2- [2′-hydroxy-5 ′-(acryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5 '-(acryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(methacryloyloxy) phenyl ] Benzotriazole, 2- [2'-hydroxy-3'-methyl-5 '-(acryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy-3'-methyl-5'-(methacryloyloxypropyl) Phenyl] -5-chlorobenzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxy L) phenyl] benzotriazole, 2- [2'-hydroxy-5 '-(acryloyloxyethyl) phenyl] benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(methacryloyloxyethyl) ) Phenyl] benzotriazole, 2- [2′-hydroxy-3′-t-butyl-5 ′-(acryloyloxyethyl) phenyl] benzotriazole, 2- [2′-hydroxy-3′-methyl-5 '-(Methacryloyloxypropyl) phenyl] -5-chlorobenzotriazole, 2- [2'-hydroxy-5'-(acryloyloxybutyl) phenyl] -5-chlorobenzotriazole, 2- [2'-hydroxy-3 -T-butyl-5- (acryloyloxyethoxycarbinylethyl) phenyl] benzotriazole and the like. It is.
[0044]
Other compounds copolymerizable with the above compounds include acrylonitrile, vinyl compounds such as acrylonitrile alkyl ester, triallylamine, radical crosslinkable monomers such as ethyl methacrylate, glycidyl acrylate, and self-condensing functional groups such as glycidyl methacrylate. Examples thereof include a monomer containing, a hydroxy group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate, and a crosslinkable compound such as a carboxylic acid monomer such as acrylic acid and methacrylic acid.
[0045]
In the present invention, the amount of the polymer ultraviolet absorber to be applied is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the fiber substrate. When the content is 0.01 part or more, more preferably 0.1 part or more, pilling due to light deterioration of the polyurethane resin can be favorably prevented. By setting the content to 30 parts by weight or less, more preferably 10 parts by weight or less, the flexibility of the sheet is not impaired, and the production cost can be suppressed.
[0046]
You may use together the said polymeric ultraviolet absorber and the conventional ultraviolet absorber. Conventional UV absorbers include, for example, oxabenzone, dioxabenzone, slisobenzone, menthyl anthranilate, para-aminobenzoic acid, octyl para-dimethylaminobenzoate, ethyl 4-bis (hydroxypropyl) para-aminobenzoate, polyethylene glycol (para- Aminobenzoate), ethyl 4-bis (hydroxylpropyl) aminobenzoate, diethinolamine, para-methoxycinnamate, 2-ethoxyethylpara-methoxycinnamate, ethylhexylpara-methoxycinnamate, octylparamethoxycinnamate, 2- Ethylhexyl 2-cyano-3,3-diphenyl-acrylate, 2-ethylhexyl salicylate, homomenthyl salicylate, glycerylaminobenzoate Triethanolamine salicylate, di galloylated trioleate, dihydroxyacetone Rauson, 2-phenyl-benzo Imi soda-5-sulfonic acid, titanium dioxide, and zinc oxide. One or a plurality of these conventional ultraviolet absorbers may be selected and used in combination with the above-mentioned polymer ultraviolet absorber.
[0047]
Here, it is also preferable to add a crosslinking agent. The technical meaning is as follows.
(A) When an emulsion-type polyurethane resin is used, the sheet tends to be easily broken when subjected to dyeing. Therefore, the polyurethane resin is reinforced by crosslinking to improve the dyeing resistance.
(B) Improve the degree of crosslinking of the polymeric UV absorber.
(C) When the sea component is an alkali-soluble type and the island component is a polyester type as a conjugate fiber-expressing conjugate fiber, when the ultrafine fiber is treated with an alkaline aqueous solution, the ultrafine fiber becomes hydrophilic, and the strength and the like are reduced. Since the physical properties tend to decrease, we will try to improve it.
[0048]
Examples of the cross-linking agent include a polyisocyanate compound, a blocked isocyanate compound, and an epoxy cross-linking agent. However, a polyisocyanate compound and a blocked isocyanate compound are particularly preferable because they do not easily impair the feeling even when added.
[0049]
The thus obtained sheet is subjected to half cutting by a slicing machine, raising by buffing, dyeing, and the like, depending on the use, to obtain a leather-like sheet.
[0050]
【Example】
The present invention will be described in more detail based on examples, but the present invention is not limited thereto. About the evaluation item shown in the Example, it measured according to the following method.
[0051]
(1) Pilling resistance after light irradiation A sample of 6.5 cm × 10 cm was irradiated with light for 144 hours using a xenon lamp irradiation device (manufactured by Suga Test Instruments Co., Ltd.).
After forced deterioration by light irradiation, a circular sample having a diameter of 3 cm was cut out from the sample, and evaluated by a Martindale method in JIS L1096 using a Martindale abrasion tester. The number of frictions up to the end point was measured, and the one that reached the set upper limit of 20,000 times of the number of frictions was determined to be acceptable.
[0052]
(Example 1)
30 parts by weight of polyethylene terephthalate obtained by copolymerizing 8 mol% of 5-sodium sulfoisophthalic acid as a sea component and 70 parts by weight of polyethylene terephthalate as an island component are formed into a sea-island type having 36 islands in one filament. The staples were composited and had an average fineness of 3.8 dtex and a fiber length of 6 cm.
[0053]
(1) Using this, a web was produced through a card and a cross wrapper, and then needle punched to produce a nonwoven fabric.
[0054]
A 12% by weight aqueous solution in which polyvinyl alcohol having a saponification degree of 95 is dissolved in hot water at 90 ° C. is added to the fiber base of the nonwoven fabric so that the solid content of polyvinyl alcohol is 30 parts by weight per 100 parts by weight of the island component of the fiber base. , And a heat treatment at 180 ° C. was performed.
[0055]
(2) The fiber substrate was immersed in a 10% by weight aqueous solution of sodium hydroxide at 40 ° C. for 30 minutes to remove sea components to develop ultrafine fibers, and then washed with water and dried.
[0056]
(3) Next, an ether-based polyurethane resin (Daiichi Kogyo Seiyaku, F-8638) was diluted with water to prepare a 12% by weight emulsion. This was poured into a bath, the fiber base was immersed in the bath, squeezed with a mangle, and 400 parts by weight of the emulsion was contained per 100 parts by weight of the fiber base. When water, an emulsifier, and the like are removed therefrom, 48 parts by weight of the polyurethane resin solid content is added to 100 parts by weight of the fiber substrate. The sheet containing the emulsion was subjected to wet heat coagulation by steam treatment, dried at 100 ° C., and subjected to a heat treatment at 130 ° C. for 5 minutes.
[0057]
Next, the polyvinyl alcohol inside the sheet was removed with hot water at 98 ° C.
[0058]
Next, the sheet was impregnated with a water-dispersed polyisocyanate solution (X-9003, manufactured by Nikka Chemical Co., Ltd.) obtained by diluting with water, and dried. The target application amount of the polyisocyanate was 6 parts by weight based on 100 parts by weight of the sheet.
[0059]
(4) Next, USL-700 (manufactured by YAS & Co., Ltd.) was diluted with water to prepare a 5% by weight aqueous solution as a high-molecular ultraviolet absorber. The sheet was impregnated so as to contain 1 part by weight with respect to 100 parts by weight, dried at 100 ° C., and heat-treated at 130 ° C.
[0060]
Next, this sheet was cut in half by a slicing machine, buffed, and dyed light brown with a jet dyeing machine using a disperse dye to obtain a leather-like sheet.
[0061]
The pilling resistance after light irradiation reached the set upper limit of 20,000 times, which was a pass level. Further, the texture and resilience of the sheet were comparable to those obtained by the conventional production method, and were at a level that could be sufficiently used.
[0062]
(Example 2)
At a ratio of 30 parts by weight of polystyrene as the sea component and 70 parts by weight of polyethylene terephthalate as the island component, the island component is compounded into a sea-island shape having 36 islands in one filament, and the average fineness of a single fiber is 3.6 dtex. Sea-island staples with a length of 6 cm were used.
[0063]
(1) Using this, a web was made through a card and a cross wrapper, and then needle punched to form a nonwoven fabric.
[0064]
A 12% by weight aqueous solution in which polyvinyl alcohol having a saponification degree of 95 is dissolved in hot water at 90 ° C. is contained in the nonwoven fabric base at a solid content of 30% by weight based on 100 parts by weight of the island component of the fiber base. After impregnation and drying treatment, heat treatment at 180 ° C. was performed.
[0065]
(2) The fiber substrate was immersed in trichlorethylene for 30 minutes to remove sea components to express ultrafine fibers, and then washed with water and dried.
[0066]
Thereafter, Example 1 was repeated to obtain a leather-like sheet.
[0067]
The pilling resistance after light irradiation reached the set upper limit of 20,000 times, which was a pass level. Further, the texture and resilience of the sheet were comparable to those obtained by the conventional production method, and were at a level that could be sufficiently used.
[0068]
(Example 3)
Basically, Example 2 was repeated to obtain a leather-like sheet.
[0069]
However, in the step (3) of applying the polyurethane resin to the fiber substrate, an organic solvent-type ether polyurethane resin having a soft segment of polytetramethylene glycol is used as the polyurethane resin, and an organic solvent is used as a means for applying the polyurethane resin. A fiber substrate was impregnated with a 12% by weight polyurethane resin solution diluted with dimethylformamide, wet coagulated, and dried.
[0070]
The pilling resistance after light irradiation reached the set upper limit of 20,000 times, which was a pass level. Further, the feel and resilience of the sheet were comparable to those obtained by the conventional production method, and were at a level that could be sufficiently used.
[0071]
(Comparative Example 1)
A leather-like sheet material was obtained in the same manner as in Example 1 except that the step of (4) for applying the polymer ultraviolet absorber was omitted.
[0072]
The pilling resistance after light irradiation was 5000 times, which was a failure.
[0073]
(Comparative Example 2)
A leather-like sheet was obtained in the same manner as in Example 2 except that the step (4) of applying the polymer ultraviolet absorber was omitted.
[0074]
The pilling resistance after light irradiation was 10,000 times, which was a failure.
[0075]
(Comparative Example 3)
A leather-like sheet was obtained in the same manner as in Example 3, except that the step of (4) for applying the high-molecular ultraviolet absorber was omitted.
[0076]
The pilling resistance after light irradiation was 15,000 times, which was a failure.
[0077]
【The invention's effect】
According to the present invention, a leather-like sheet having excellent pilling resistance can be provided.

Claims (3)

A method for producing a leather-like sheet, comprising the following four steps in producing a leather-like sheet mainly comprising a fiber base having ultrafine fibers and a polyurethane resin.
(1) A step of producing a fiber substrate using an ultrafine fiber-expressing conjugate fiber that expresses an ultrafine fiber.
(2) A step of developing ultrafine fibers.
(3) A step of applying a polyurethane resin to the fiber substrate.
(4) A step of applying a high-molecular ultraviolet absorber after the step (3). The method for producing a leather-like sheet according to claim 1, wherein the polymer ultraviolet absorber contains at least one selected from a 2-hydroxybenzophenone derivative and a 2-hydroxybenzotriazole derivative as a component of the polymer. The method for producing a leather-like sheet according to claim 1 or 2, wherein the polyurethane resin is an ether type.