JP2001200481A - Leather-like sheet substrate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet substrate excellent in flexibility and sense of fitting, also excellent in dyeability and color fastness to dyeing, having high compactibility of the surface nap fiber required for a suede-like artificial leather, and excellent in feeling, writing effect and drape. SOLUTION: This leather-like sheet substrate constituted of an entangled nonwoven fabric comprising polyamide-based ultrafine fiber bundles, and an elastic polymer included therein is characterized by 2-10% degree swelled by hot toluene of the polyamide constituting the polyamide-based ultrafine fiber bundles, <=0.1 dtex size of the ultrafine fiber constituting the polyamide-based ultrafine fiber bundles, and no mold-releasing agent imparted to the space between the bundles of the entangled nonwoven fabric and the interior of the bundles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet used as a base of a suede-like or smooth-tone leather-like sheet and a method for producing the same. More specifically, the present invention relates to a leather-like sheet substrate which is flexible, has a sense of fulfillment, and has excellent workability and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, for the purpose of improving the flexibility and fullness of a leather-like sheet, shrinkage treatment of a fiber-entangled nonwoven fabric used for a leather-like sheet substrate has been widely performed. For example, in the case of fiber-entangled nonwoven fabrics made of polyamide-based fibers, calcium chloride, zinc chloride, and aqueous solutions of lithium chloride, phenol, benzyl alcohol, benzoic acid, and other aqueous solutions and dispersions of polyamide-based nonwoven fabrics have long been used. A number of techniques have been proposed for treating and swelling fibers to shrink the fibers.

[0003] On the other hand, in the case of a fiber entangled non-woven fabric made of polyester fiber, the fiber entangled non-woven fabric is shrunk by utilizing the fact that the low draw ratio fiber and the high-speed spun fiber of polyethylene terephthalate have heat shrinkability.・ Techniques for densification are widely known. For example, JP-B-53-20561 and JP-B-53-20562 disclose that a woven or knitted fabric of multicomponent fibers composed of polyamide and polyester is subjected to a chemical treatment such as benzyl alcohol to cause the polyamide component to shrink and exfoliate. The production of artificial leather is described.

Japanese Patent Application Laid-Open No. 3-90619 discloses that a tubular knitted or plain woven fabric made of a copolyamide / polyester splittable conjugate fiber is treated with a heated alkali aqueous solution to split the fibers between the constituent polymers and shrink the fibers. A method for producing a fabric using a polyamide / polyester splittable conjugate fiber whose surface is covered only with polyester ultrafine fibers and colored only with a polyester fiber dye is described. Japanese Patent Publication No. 28786868 discloses that a nonwoven fabric made of sea-island cross-section fibers in which the island component is polyamide and the sea component is formed of polyethylene is treated with an aqueous benzoic acid solution to shrink the polyamide to produce a suede-finished leather-like sheet. A method is described.

As described above, in these methods, a method is used in which polyamide fibers are treated with an aqueous solution or dispersion of a drug such as phenol, benzyl alcohol, or benzoic acid to swell or shrink. However, these methods are not only disadvantageous in that the concentration of the processing liquid tends to change due to evaporation or sublimation, and thus it is difficult to stabilize the shrinkage rate. There were also problems with the technology that controlled it. Furthermore, the safety of the used chemicals is serious, and it is necessary to take sufficient measures against the working environment and environmental pollution, and equipment for collecting the used chemicals is indispensable, which is a heavy burden in industrial production.

[0006] In recent years, the degree of demand for the feeling, feel, color, and the like of products has been increasing year by year. Is done. For example, when dyeing in a post-process, in a leather-like sheet composed of a polyester-based fiber entangled nonwoven fabric and a polyurethane-based elastic polymer, the dyeing fastness becomes extremely low when the disperse dye that dyes the fibers is dyed on polyurethane. For this reason, a dyeing method has been used in which a polyester fiber is dyed with a disperse dye, the disperse dye dyed on the polyurethane is decolorized once, and then the polyurethane is re-dyed with a metal complex dye. However, in such a method, the process is complicated, and when a resin is applied to the surface in a smooth tone or when hot embossing is performed for embossing, the disperse dye in the polyester fiber is transferred to polyurethane, and the color fastness is increased. There were problems such as lowering.

On the other hand, in the case of a leather-like sheet composed of a polyamide-based entangled nonwoven fabric and a polyurethane-based polymer, a relatively good color fastness can be obtained by dyeing a metal complex salt dye in the subsequent step. Although it can be expected, the shrinkage and densification of the fiber entangled non-woven fabric cannot be performed sufficiently, it is difficult to give a feeling of fulfillment of natural leather, and it is flexible, but it can not escape from the feeling of rubber There is a problem that. Also in the case of suede preparations, if flexibility is emphasized, the number of contact points between the fiber and the polyurethane polymer must be reduced, and if the number of contact points is reduced, there is a problem that surface nap fibers are dropped off.

[0008]

SUMMARY OF THE INVENTION In view of the foregoing problems, the present invention provides a flexible non-woven fabric containing polyamide-based ultrafine fiber-generating fibers, which can be easily handled and has a stable shrinkage rate. The present invention provides a leather-like sheet substrate having a fullness and excellent workability, and a method for producing the same.

[0009]

That is, the present invention comprises a bundle of polyamide-based ultrafine fibers comprising a polyamide or a polyamide composition having a hot toluene swelling degree of 2 to 10% and a fineness of 0.1 decitex or less. An elastic polymer and a release agent are contained between the bundles of the entangled nonwoven fabric, and a leather-like sheet substrate in which a release agent is further provided inside the bundle, preferably, the polyamide-based fiber is ,Nylon
The leather-like sheet substrate as described above, which is a fiber comprising a polyamide or a polyamide composition having -6 units and nylon-12 units. Further preferably, the above-mentioned leather-like sheet substrate is such that the release agent present between the fiber bundles and in the fiber bundle is a salt compound of a polyamide derivative or a silicone compound.

Further, the present invention provides a method for producing a leather-like sheet substrate comprising a polyamide-based ultrafine fiber and an elastic polymer.
A method for producing a leather-like sheet base, comprising sequentially performing the following steps () to (V). (I) An entangled nonwoven fabric is produced from a polyamide microfine fiber-generating fiber which is made of a polyamide or a polyamide composition having a thermal toluene swelling degree of 2 to 10% and has a fineness of 0.1 decitex or less. Process,
(II) a step of subjecting the entangled nonwoven fabric to hot water treatment to shrink the area by 15 to 50%, (III) a step of impregnating and coagulating the contracted entangled nonwoven fabric with an elastic polymer, and (IV) the ultrafine fiber generating fiber. (V) a step of applying a release agent before the drying treatment performed after the step IV.

In the present invention, the ultrafine fiber-generating fiber is a fiber having a sea-island structure cross section in which the island component is made of polyamide having the above-mentioned degree of swelling, and the sea component is preferably polyethylene, particularly preferably low density polyethylene. Is mentioned. As a method of converting the ultrafine fiber-generating fiber into an ultrafine fiber bundle, a method of extracting and removing polyethylene as a sea component with hot toluene at 75 to 95 ° C is generally used. Polyamide-based fibers comprising a polyamide having a swelling degree defined in the present invention have an extremely excellent property that uniform shrinkage can be generated and the degree of the shrinkage can be freely controlled. In the process of converting into fiber bundles, it is generally easy to swell with hot toluene, and in the press process in hot toluene to promote extraction and removal, the sticking phenomenon between the fine fibers between and within the fine fiber bundles Is easy to occur. When the sticking between the ultrafine fibers is excessive, not only the texture of the product is hardened, but also the aesthetic appearance and touch feeling of the surface in a suede tone are deteriorated.

The polyamide constituting the ultrafine polyamide fiber of the present invention has a degree of hot toluene swelling of 2 to 10%, preferably 4 to 7%. When the content is less than 2%, the nonwoven fabric of the present invention is a polyamide-based ultrafine fiber which cannot exhibit performance such as softness due to hot water shrinkage. On the other hand, if it exceeds 10%, the ultrafine fibers are strongly agglutinated, and even if an anti-adhesion agent is applied and the anti-adhesion treatment is performed in a later step, the effect is not recognized.

In the present invention, after converting the ultrafine fiber-generating fibers into ultrafine fiber bundles, a release agent, that is, an anti-sticking agent is applied.
As the release agent, a salt compound of a polyamide derivative or a silicone compound is preferable. Particularly, a salt compound of a polyamide derivative has an effect on the ease of buffing with sandpaper or the like and the feeling of touch on the surface when used as a suede-like artificial leather. Is preferred in that there is little. The rate of application of the release agent is preferably from 0.2 to 1.0% in terms of solid content based on the weight of the sheet substrate, since the influence on the surface touch is small, and more preferably from 0.4 to 0.6%. In the present invention, a suitable polyamide derivative is a compound represented by the general formula of Chemical Formula 1 or Chemical Formula 2 or a polycondensate of epihalohydrin thereof, provided that Chemical Formula 1 and Chemical Formula 2
R ₁ and R ′ ₁ are an alkyl group having 11 to 25 carbon atoms, R ₂ is an alkylene group having 2 or 3 carbon atoms, and R ₃ and R ′ ₃ are H or intermolecular cross-linking, which are the same or different. And n represents a number of 1 to 8. Preferred examples of the salt compound include compounds represented by the following chemical formulas (3), (4), (5), and (6). Among them, ease of buffing with sandpaper and the like and touch feeling on the surface are particularly preferable. The compound represented by Chemical Formula 3 is more preferable because it has little effect on the compound.

[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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The polyamide derivative used in the present invention is obtained by dehydrating and condensing a higher fatty acid having 11 to 25 carbon atoms in an alkyl group with a polyalkylene polyamine having 2 to 3 carbon atoms in an alkylene group, Alternatively, it can be obtained by polycondensing a compound represented by the above general formula obtained by crosslinking with thiourea or the like or epihalohydrin. Examples of higher fatty acids used for this include lauric acid, myristic acid, palmitic acid,
Examples thereof include stearic acid, argidic acid, and pehenic acid. Among them, higher fatty acids having an alkyl group having 17 or more carbon atoms are preferable. Examples of the polyalkylene polyamine include ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, propylene diamine, and dipropylene triamine. When further reacted with epihalohydrin, since epihalohydrin is a bifunctional compound, the polyamide derivative is cationized and crosslinked, and as a result, a salt compound is obtained.

Examples of the silicone compound include a compound represented by the following formula 7, and preferable specific examples thereof include dimethyl silicon, methyl phenyl silicon, methyl hydrogen silicon, amino-modified silicon, and alkyl-modified silicon. Among them, amino-modified silicon is preferred because of its high mold release effect.

[0022]

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The release agent is applied by extracting and removing the sea component polyethylene with hot toluene to convert it into ultrafine fiber bundles, and removing the residual toluene in the substrate azeotropically in hot water.
In the state of et and the state where the pseudo-agglutinated portions of the ultrafine fibers are not fixed, it is preferable that the substrate is immersed in an aqueous solution of the release agent to apply the release agent, and then dried. When converted to ultrafine fiber bundles and residual toluene is azeotropically driven out with hot water, and then dried to remove the water almost completely, and then a release agent is applied, the pseudo-adhered portion of the ultrafine fibers is already fixed The effect of the release agent cannot be expected sufficiently.

Preferable examples of the polyamide serving as an island component of the ultrafine fiber generating fiber constituting the present invention include polyamide or polyamide having a 6-nylon unit and a 12-nylon unit in a weight ratio of 60/40 to 95/5. A composition,
More preferably, the polyamide or the polyamide composition has a melting point of 185 ° C. or more.
Examples of such polyamides or polyamide compositions are those having “mainly” 6-nylon units and “having” 12-nylon units in the above-mentioned weight ratio range. Polyamide or polyamide which may have "at least 30% by weight or less of at least one component such as -66 units, nylon-6I units (polymer units of hexamethylenediamine and isophthalic acid), nylon-610 units. A composition. The term "having" as used in the present invention means both a case where it is present in a copolymerized state and a case where it is present merely in a blended state.
Also, copolymerization, when copolymerized in a block state,
Either a case where the copolymer is copolymerized in a random state or a case where the copolymer is copolymerized in a graft state may be used. Preferably, for example, a two-component copolymer of 6-nylon and 12-nylon, or 6-nylon, 66-nylon and 12-nylon
It is a three-component copolymer with nylon, and can be adjusted to a desired melting point by combining the number of components to be copolymerized, the copolymerization ratio, and the copolymerization state. Preferably, the block copolymer is a block copolymer in which 6-nylon units and 12-nylon units are connected to each other with an appropriate length and exist in a block shape, and have an appropriate crystallinity even after fiber formation. Of course, in the present invention, the polyamide or the polyamide composition may be blended with another polymer as long as the object of the present invention is not impaired.

When the content of the 12-nylon unit is less than 5% by weight based on the total amount of the 6-nylon, the 6-nylon remains in a state of maintaining high crystallinity and the hot toluene swelling ratio is 2%. %, The adhesive phenomenon of the ultrafine fibers does not occur, but the desired hot water shrinkage rate cannot be obtained. Further, when the copolymerization component is set to 40% by weight or more to improve the hot water shrinkage ratio and the crystallinity is lowered, the melting point is excessively lowered and easily melted and decomposed at the time of spinning or post-finishing. Therefore, the obtained fiber entangled nonwoven fabric has a low strength, a high degree of swelling in hot toluene, and a vigorous sticking phenomenon of the ultrafine fibers, resulting in low practicality.

The polyamide must have a melting point of 185 ° C. or more in order to perform good post-processing such as dyeing and heat setting. In particular, it preferably has a melting point of 190 ° C. or more and 220 ° C. or less. The value of the melting point can be set to a target level by optimizing the copolymer composition and the block chain length. The melting point referred to in the present invention is a main peak temperature of a chart obtained when measured by DSC in a sufficiently crystallized state. The degree of polymerization of the polyamide is desirably about 2.5 to 3.2 in terms of sulfuric acid relative viscosity ηrel in consideration of stretchability during spinning. In addition, additives such as various stabilizers and coloring agents may be added to the polyamide as long as the basic characteristics are not impaired.

In the present invention, the sea component of the ultrafine fiber generating fiber is preferably a polyethylene polymer.
More preferably, a low density polyethylene polymer is used. Examples of the polyethylene-based polymer include a polyethylene-based polymer that is generally commercially available, and of course, a polyethylene-based polymer obtained by copolymerizing other monomer units may be used. Above all, MI measured by ASTM D1238
A low-density polyethylene having a (melt index) of 50 to 200 g / 10 min has good fluidity, and is particularly preferable in that it has excellent spinning stability of a multicomponent fiber with the polyamide polymer used in the present invention. . Of course, a substance that activates the extraction rate may be added to the polyethylene-based polymer. In the present invention, since the polyethylene polymer and the polyamide polymer are extracted and removed later, the polyethylene polymer and the polyamide polymer are not uniformly mixed, that is, they are not miscible or compatible. Specifically, in the fiber after spinning, it is necessary that polyethylene is present as a sea component and the polyamide is present as an island component separately.

Such a sea-island type multicomponent fiber, that is, an ultrafine fiber-generating fiber, is prepared by mixing a polymer constituting an island component and a polymer constituting a sea component at a predetermined mixing ratio, and melting and spinning in the same melting system. Or a method of spinning by melting the polymer constituting the island component and the sea component polymer in separate melting systems, forming a mixed system of the two by repeating joining-split multiple times at the spinning head, or The two can be obtained by a method in which the two are combined by defining the fiber shape in a spinneret structure and then spun. The area ratio of the polyamide ultrafine fiber component of the island component to the cross section of the sea-island type multicomponent fiber of the present invention is 40.
-80% is preferable in terms of spinning stability and economy. In addition,
In the present invention, as the island component constituting the ultrafine fiber-generating fiber, an island component composed of a polymer other than the polyamide may be present within a range that does not impair the object of the present invention.

In the stretching treatment of the sea-island type multicomponent fiber, it is important to draw the sea-island type multicomponent fiber at a temperature equal to or lower than the softening point of polyethylene as a sea component.
As a result, the polyamide fiber, which is an island component, is stretched while being held by the polyethylene, so that the contracting force of the polyamide fiber can be fixed by the polyethylene,
Thereby, at the time of the hot water treatment after the formation of the fiber entangled nonwoven fabric, the area shrinkage occurs due to the manifestation of the shrinkage of the polyamide fiber accompanying the softening of the polyethylene. Regarding the area shrinkage at this time, a higher shrinkage can be obtained by treating at a lower temperature during stretching. In the present invention, the temperature of the stretching bath is 50 to 70.
It is desirable to carry out the treatment at a temperature of 50 ° C., especially 50 to 60 ° C.

Next, this sea-island type multicomponent fiber is crimped,
Through processing steps such as drying and cutting, staple fibers having a fineness of 2 to 10 dtex and a fiber length of 15 to 100 mm are obtained. The thus obtained sea-island type multicomponent fiber is opened with a card, blended with other fibers as necessary, a random web or a cross-wrap web is formed through a webber, and the obtained fiber web is weighed to a desired weight. Then, laminate to the thickness. Next, entanglement treatment is performed by a known method such as needle punching or high-speed fluid flow treatment to obtain a nonwoven fabric. Of course, the nonwoven fabric may be overlapped with another nonwoven fabric or with a woven or knitted fabric, so that the surface of the final product is a nonwoven fabric layer obtained from the sea-island type multicomponent fiber.

Next, the fiber entangled nonwoven fabric mainly composed of the sea-island type multicomponent fibers is contracted by immersing it in hot water. At that time, it is important that the treatment is performed at a temperature higher than the temperature at which the low-density polyethylene as the sea component in the sea-island type multicomponent fiber is softened so as not to hinder the shrinkage stress of the island component polyamide fiber. The temperature is 85-9
It is desirable to treat with hot water at 5 ° C, particularly 90 to 95 ° C. The area shrinkage of the fiber entangled nonwoven fabric is 15 to 50.
% Is preferred. If the area shrinkage is less than 15%, the feeling, fullness and feather fixability are not sufficient. Conversely, if the area shrinkage is more than 50%, the polyamide copolymerization and blending ratio must be increased to increase the shrinkage. It is necessary to increase the size, and not only the degradation of the polyamide fiber becomes large, but also the degree of swelling of the ultrafine fiber increases during the hot toluene treatment for converting the ultrafine fiber generating type fiber into the ultrafine fiber bundle, and the ultrafine fiber sticks. The phenomenon becomes severe, and the resulting leather-like sheet has a hard texture and a low strength, which is not preferable.

The surface of the shrink-treated fiber entangled nonwoven fabric is smoothed by hot pressing if necessary, or the fiber entangled nonwoven fabric is impregnated with a temporary fixing agent represented by polyvinyl alcohol to form the nonwoven fabric. Is temporarily fixed to prevent the non-woven fabric form from being destroyed in the subsequent step, and then the fiber-entangled non-woven fabric is impregnated with a solution or dispersion of a polymer elastic material to be solidified or gelled. As the polymer elastic body, a resin conventionally used for producing a leather-like sheet is preferably used. That is, polyurethane resin, polyvinyl chloride resin, polyacrylic acid resin,
Polyamino acid-based resins, silicon-based resins, and copolymers and mixtures thereof correspond to this. Of these, polyurethane resins are preferred in terms of texture balance,
Among polyurethane resins, at least one polymer diol having an average molecular weight of 500 to 3000 selected from polyester diol, polyetherol, polyetherester diol, polycarbonate diol, etc., and 4,4′-diphenylmethane diisocyanate, isophorone diisocyanate , At least one diisocyanate selected from aromatic, alicyclic, and aliphatic diisocyanates such as hexamethylene diisocyanate and at least one dihydrogen isocyanate having at least two active hydrogen atoms such as ethylene glycol and ethylenediamine A compound obtained by reacting with a low molecular weight compound at a predetermined molar ratio is preferably used. Additives such as a colorant, a coagulation regulator, and an antioxidant are added to the elastic polymer liquid as needed. The amount of the polymer elastic body occupying the fibrous substrate after the ultrafine fiber treatment is preferably contained as a solid component in a range of 20 to 60% by weight, and the weight ratio of the solid component is adjusted depending on the product field. It is preferable to keep the balance between the fiber and the elastic polymer. As a method of solidifying the polymer elastic body, a wet solidification method is preferable in that a porous solidified product is obtained and a natural leather-like texture is obtained.

The fibrous base material impregnated and solidified with the solution or dispersion of the elastic polymer is then used as a non-solvent and non-decomposer for the ultrafine fibers and the elastic polymer, and a solvent or sea component of the islands-in-sea multicomponent fiber. By dissolving or decomposing and removing the sea component with a liquid that is a decomposing agent, particularly in the present invention, the sea component, that is, polyethylene is preferably dissolved and removed from the microfine fiber and the polymer elastic body by dissolving and removing the polyethylene with hot toluene. A leather-like sheet substrate is obtained. The thickness of the ultrafine fibers is preferably 0.3 decitex or less from the viewpoint of leather-like texture, touch, and appearance, and more preferably 0.1 decitex or less and 0.001 decitex or more. The fibrous substrate is immersed in warm water to remove residual toluene from the fibrous substrate in which the polyethylene component has been dissolved and removed, and it is preferable that the release agent described above be added to the warm water at that time. As described above, by the addition of the mold agent, it is possible to prevent the ultrafine fibers or the ultrafine fiber bundles from excessively sticking together during the subsequent drying treatment.

Next, as a method of obtaining a suede-like leather-like sheet, this leather-like sheet substrate is sliced into a plurality of sheets in the thickness direction as required, and at least one surface thereof is subjected to a brushing treatment to mainly use ultrafine fibers. The raised fiber surface is formed. A known method such as buffing with a sandpaper or the like is used as a method for forming the fiber raised surface.
The preferred thickness of the suede-like artificial leather is 0.4 to 2.
The range is 5 mm.

Next, the obtained suede-finished leather-like sheet substrate is dyed. Dyeing is carried out using a dye capable of forming a terminal amino group of polyamide as a dyeing group. Examples of such dyes include acid dyes, metal complex dyes, and reactive dyes. The dyed suede-like fibrous base material is subjected to finishing treatments such as fir, softening, and brushing to obtain a suede-like leather-like sheet having an elegant appearance and no fluff falling off.

Further, the artificial leather substrate of the present invention can be suitably used in the field of artificial leather with silver. That is, a silver surface layer is formed by bonding a film to be a silver surface layer to the surface of the artificial leather substrate, or by coating or gravure coating a resin emulsion, a resin solution, a resin melt, or the like, By applying a finishing treatment such as embossing or coloring to the surface, a soft and rich artificial leather with silver tone can be obtained.

The degree of swelling of hot toluene and the thickness of the ultrafine fibers referred to in the present invention mean the values measured by the following methods. [Measurement method of thermal toluene swelling degree] The resin pellet used for the ultrafine fiber was vacuum-dried at 105 ° C for 4 hours to adjust the moisture content to 300 to 600 ppm, and then was pressed using a press molding machine.
Formed into a 100 μm film at a temperature of 0 ° C.
Leave it in a room at room temperature of 25 ° C. for 4 hours to obtain a test sample. The sample was cut into a square having a side of 10 cm, and the weight (W ₀ ) was measured. Then, the sample was immersed in hot toluene at 90 ° C. for 1 hour, and was taken out of the hot toluene and the toluene attached to the surface was wiped off to obtain a weight (W). Is measured, and the swelling ratio is calculated according to the following formula. Swelling ratio (wt%) = (W−W ₀ ) × 100 / W ₀

[Thickness of Ultrafine Fiber] The cross section of the ultrafine fiber-generating fiber is taken in a micrograph, the number of islands in one fiber cross section is counted, and the total thickness of the ultrafine fiber bundle of the final product is calculated by the number of islands. Calculate by dividing.

[0039]

EXAMPLES Next, the embodiments of the present invention will be described with reference to specific examples. Parts and percentages in the examples relate to weight unless otherwise specified.

Example 1 Copolymerized nylon consisting of 6-nylon units and 12-nylon units (6-nylon / 12-nylon = 80/2)
0, melting point 202 ° C, hot toluene swelling 5.5%) 5
0 parts used as island component, polyethylene as sea component
(Melt index = 70) 50 parts were melted in the same melting system and spun to obtain an ultrafine fiber-generating fiber having a fineness of 10 dtex. At this time, when the fiber cross section was observed, the average number of islands was about 600. Then the obtained fiber is
The film was stretched 3.4 times in a warm bath at 0 ° C., crimped, and then cut to a fiber length of 51 mm to produce a staple fiber having a fineness of 3.0 dtex. After the staple fiber was defibrated with a card, the web was formed with a cross wrap webber. Next, a fiber-entangled nonwoven fabric having a basis weight of 650 g / m ^{2 was obtained} by needle punching. This fiber-entangled nonwoven fabric was immersed in hot water at 95 ° C. to cause shrinkage with an area shrinkage of about 35% to obtain a fiber-entangled nonwoven fabric with a basis weight of 1000 g / m ² . Next, 13 parts of a polyurethane composition mainly composed of a polyether polyurethane as a polymer elastic body,
87 parts of a composition solution of dimethylformamide (hereinafter abbreviated as DMF) was impregnated and wet coagulated. After washing with water, the polyethylene in the ultrafine fiber-generating fibers was extracted and removed with hot toluene at 85 ° C., and the toluene in the substrate was azeotropically driven out in hot water at 95 ° C. Wet after dismissing toluene
Is replaced with an aqueous solution of a 1% pure compound of a salt of a polyamide derivative (compound name: epichlorohydrin quaternary salt of triethylenetetramineamide behenate), dried at 140 ° C., and dried with 6-nylon. Copolymerization of / 12-nylon A fibrous base material having a thickness of about 2.2 mm and comprising a bundle of ultrafine fibers and polyurethane was obtained. This fibrous substrate was sliced into two parts to obtain a fibrous substrate for suede-like artificial leather having a thickness of about 1.1 mm.

When the cross section of the ultrafine fiber bundle of the fibrous base material for suede-like artificial leather was observed with an electron microscope, the average fineness was 0.0032 dtex. After buffing one surface of the substrate and adjusting the thickness to 0.80 mm, the other surface was treated with an emery buffing machine to form a nap surface of ultrafine fibers, and further, Irgalan Brown 2BLN (Chiba) was used as a dye.
Geigy) at a concentration of 4% owf. The suede-like artificial leather obtained by finishing is vividly dyed, has excellent dyeing fastness, has excellent surface nap, and has good appearance, texture, touch feeling, drape, and almost no fluff. Was something. From the result of this example and the result of Comparative Example 3 described later, it is understood that the salt compound of the polyamide derivative exists inside the ultrafine fiber bundle and between the fiber bundles, and prevents the fiber adhesion.

Example 2 Nylon copolymerized with 6-nylon unit and 12-nylon unit (6-nylon / 12-nylon = 90/1)
0, melting point: 213 ° C., hot toluene swelling: 3%), and polyethylene (melt index) as a sea component
= 70) A method of melting 50 parts in each melting system, repeating joining-division at the spinning head a plurality of times to form a mixed system of the two and spinning to obtain an ultrafine fiber-generating fiber having a fineness of 16 denier. Was. At this time, when observing the cross section of the fiber,
The average number of islands was about 200. Next, the obtained fiber was stretched 3.8 times in a warm bath at 50 ° C., crimped, and then cut to a fiber length of 51 mm to produce a staple fiber having a fineness of 4.2 dtex. After the staple fiber was defibrated with a card, the web was formed with a cross wrap webber. Next, with a needle punch, the basis weight is 780 g / m ^2.
Fiber entangled nonwoven fabric. 95 ° C
In hot water to cause shrinkage with an area shrinkage of about 20% to obtain a fiber-entangled nonwoven fabric having a basis weight of 975 g / m ² . Then, a polyurethane composition 13 mainly composed of a polyether-based polyurethane was used as a polymer elastic body in this fiber-entangled nonwoven fabric.
And 87 parts of DMF, were wet impregnated. After further washing with water, the polyethylene in the ultrafine fiber generating fiber was extracted and removed in toluene, and then the toluene in the substrate was azeotropically expelled in hot water at 95 ° C. 1% pure compound of a salt compound of a polyamide derivative (compound name: epichlorohydrin quaternary salt of behenic acid triethylenetetramine amide) on a wet fibrous base material after the displaced toluene.
And dried at 140 ° C. to obtain a fibrous substrate having a thickness of about 2.2 mm and comprising a bundle of copolymerized nylon ultrafine fibers and polyurethane. This fibrous base was sliced into two parts to obtain a fibrous base having a thickness of about 1.1 mm.

When the cross section of the ultrafine fiber bundle of this fibrous substrate was observed with an electron microscope, the average fineness was 0.012 dtex. One surface of the substrate is buffed to a thickness of 0.8.
After adjusting the thickness to 0 mm, the other surface was treated with an emery buffing machine to form a nap surface of ultrafine fibers, and 4% o using Irgalan Brown 2BLN (Chiba Geigy) as a dye.
Stained at a concentration of wf. The suede-like artificial leather obtained by the finishing is vividly dyed in the same manner as in Example 1, and furthermore, has excellent dyeing fastness, has excellent surface nap, and has excellent appearance, texture, touch, and drape. Both sexes were good and there was almost no fluff shedding. From the results of this example and the results of Comparative Example 4 to be described later, it is understood that the salt compound of the polyamide derivative exists inside the ultrafine fiber bundle and between the fiber bundles, and prevents inter-fiber sticking.

Comparative Example 1 Copolymerized nylon of 6-nylon unit and 12-nylon unit (6-nylon / 12-nylon = 50/50,
Melting point 125 ° C, hot toluene swelling degree 14%) 50 parts, polyethylene as sea component (melt index =
70) Using 50 parts, these were melted in the same melting system and spun to obtain ultrafine fiber-generating fibers having a fineness of 10 dtex. At this time, when the cross section of the fiber was observed, the average number of islands was about 600. Next, the obtained fiber was stretched 3.4 times in a warm bath at 50 ° C., crimped, and then cut to a fiber length of 51 mm to produce a staple fiber having a fineness of 3.0 dtex. After the staple fiber was defibrated with a card, the web was formed with a cross wrap webber. next,
A fiber entangled nonwoven fabric having a basis weight of 600 g / m ^{2 was obtained} by needle punching. This fiber entangled nonwoven fabric was immersed in hot water at 95 ° C. to obtain a fiber entangled nonwoven fabric having a basis weight of 1300 g / m ² and an area shrinkage of about 55%. Next, the treatment after the impregnation of the polymer elastic body was performed in the same manner as in Example 1. The obtained suede-like artificial leather was extremely stuck to ultrafine fibers, hard in both texture and touch, lacked in drape property, and lacked strength in physical properties.

Comparative Example 2 50 parts of 6-12 copolymerized nylon (6-nylon / 12-nylon = 97/3, melting point 217 ° C., degree of swelling in hot toluene 1%) were used, and polyethylene was used as a sea component (melt index = 70). ) 50 parts, these were separately melted in each melting system, and the joining-division was repeated a plurality of times at the spinning head to form a mixed system of the two and spun to produce ultrafine fibers having a fineness of 16 dtex. A shaped fiber was obtained. At this time, when a cross section with a fiber was observed, the average number was about 200. Next, the obtained fiber is heated to 50 ° C.
Was stretched 3.8 times in a warm bath, and crimped, and then cut to a fiber length of 51 mm to produce staple fibers having a fineness of 4.2 dtex. After the staple fiber was defibrated with a card, the web was formed with a cross wrap webber. Next, a fiber-entangled nonwoven fabric having a basis weight of 850 g / m ^{2 was formed} by needle punching. When this fiber entangled nonwoven fabric was immersed in hot water at 95 ° C., shrinkage of about 11% in area shrinkage was obtained, and a fiber entangled nonwoven fabric with a basis weight of 970 g / m ² was obtained. Then
The treatment after the impregnation of the polymer elastic body was performed in the same manner as in Example 2. In the obtained suede-like artificial leather, no sticking of the fine fibers was observed, but the fluff of the surface nap fibers was conspicuous, the texture was paper-like, and the flexibility and surface nap appearance were poor.

Comparative Example 3 A suede was prepared in the same manner as in Example 1 except that the wet-type fibrous base material after the removal of toluene was replaced with an aqueous solution of a salt compound of a polyamide derivative and dried directly. Toned artificial leather was produced. The obtained suede-like artificial leather had severe agglomeration of ultrafine fibers, was hard in both texture and touch, and lacked drape.

Comparative Example 4 A suede was prepared in the same manner as in Example 2, except that the wet fibrous base material after the toluene was removed was replaced with an aqueous solution of a salt compound of a polyamide derivative and dried directly. Toned artificial leather was produced. As in Comparative Example 3, the obtained suede-like artificial leather had severe agglomeration of ultrafine fibers, was hard in texture and touch, and lacked drape.

[0048]

Industrial Applicability The leather-like sheet of the present invention is soft and excellent in fullness, excellent in dyeability and excellent in color fastness, and has high sensitivity mainly for clothing as a suede-like artificial leather and a silver-like artificial leather. It is suitable for the field where is required. Especially as suede-like artificial leather, the denseness of the surface nap fiber is high,
Excellent texture, lighting and drape. Further, the shrinkage ratio, which was unstable in the conventional production method, can be obtained by a method that is industrially stabilized.

Claims (6)

[Claims] 1. A polyamide or polyamide composition having a degree of swelling in hot toluene of 2 to 10%, and a fineness of 0.1%.
A leather-like entangled non-woven fabric comprising a bundle of polyamide ultrafine fibers of 1 dtex or less, wherein the bundle contains an elastic polymer and a release agent, and the release agent is provided inside the bundle. Sheet substrate. 2. The leather-like sheet substrate according to claim 1, wherein the polyamide fiber is a fiber comprising a polyamide or a polyamide composition having nylon-6 units and nylon-12 units. 3. The leather-like sheet substrate according to claim 1, wherein the release agent is a salt compound of a polyamide derivative or a silicone compound. 4. A method for producing a leather-like sheet substrate, wherein the following steps (I) to (V) are sequentially performed. () Preparation of an entangled nonwoven fabric from a polyamide-based ultrafine fiber-generating fiber which is made of a polyamide or a polyamide composition having a thermal toluene swelling degree of 2 to 10% and generates a polyamide-based ultrafine fiber having a fineness of 0.1 decitex or less. (II) a step of subjecting the entangled nonwoven fabric to 15-50% area shrinkage by hot water treatment, (III) a step of impregnating and coagulating the contracted entangled nonwoven fabric with an elastic polymer, (IV) the ultrafine fibers Converting the generated fiber into an ultrafine fiber bundle, (V) applying a release agent before the drying treatment performed after the step IV, 5. The method according to claim 4, wherein the polyamide fiber is a fiber comprising a polyamide or a polyamide composition having nylon-6 units and nylon-12 units. 6. The method according to claim 4, wherein the release agent is a salt compound of a polyamide derivative or a silicone compound.