JP2000303368A - Suede finish leather-like sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suede finish leather-like sheet that has unchanging color tone even after a long time course and retain a fabric hand of high class. SOLUTION: The base body of leather-like sheet composed of nonwoven fabric and polyurethane impregnated therein is coated with a polyurethane solution on its at least one face, then the polyurethane layer is coagulated through the wet process to form a porous layer and the porous layer is polished on its surface to produce the objective suede finish leather-like sheet. In this case, a coagulation-controlling agent of which the silicone main chains or side chains are partially modified with urethane is added to the polyurethane solution for the porous layer and they are coagulated through the wet process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a colored polyurethane layer on the surface used for shoes, auxiliary materials, bags, etc., and its surface is fluffed in a suede tone, and its color tone changes. The present invention relates to a suede-like leather-like sheet and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a suede-like leather-like sheet used for shoes and bags, a sheet having a colorful surface or a glossy sheet has been used to give a sense of quality. In addition, since the texture is soft and the surface embossability such as embossing is good, the suede-finished leather-like sheet is provided with a porous polyurethane layer on the surface of the base layer,
A leather-like sheet whose surface is ground is used. The method of applying the porous polyurethane layer is roughly classified into a dry method in which a solution of a polymer mainly composed of a polyurethane resin is applied to a support such as a film or a leather-like sheet substrate, and a solvent is removed by evaporation. A polyurethane solution is applied to a support such as a film or a film, and immersed in a solution which is a non-solvent for the polyurethane and a solvent for the solvent constituting the polyurethane solution to solidify the polyurethane solution. Although there are two types of wet coagulation methods, the dry method usually has poor porosity and poor texture of the polyurethane layer, whereas the porous polyurethane layer obtained by the wet method has excellent texture. Therefore, it is currently generally used for high-grade leather-like sheets.

However, the porous polyurethane obtained by the wet method needs to adjust the pore size in order to control the physical strength and the hand, and a small amount of a silicone-based regulator is used as the regulator, and the effect is high. Has been used. That is, when a silicone-based coagulation regulator is added to a polyurethane solution and wet coagulated, a porous layer having a pore size suitable for a suede-like leather-like sheet is formed. More specifically, a coagulation control agent generally made of a silicone compound has an effect of making the pore size of a porous structure small and uniform during wet coagulation of polyurethane, and is used as a coagulation control agent of polyurethane applied to the surface of a leather-like sheet. if you did this,
Since the porous structure of the formed polyurethane is uniform, a sheet obtained by grinding the surface of such a porous layer can have a uniform fluffy surface without unevenness. It has also been used for the purpose of imparting water repellency to the surface.

However, in the case of a porous polyurethane layer obtained by using a silicone-based coagulation controlling agent, clouding occurs on the fluff surface due to migration of polyurethane oligomer due to aging, and the surface becomes sooty and dirty. There was a particular problem in using it for shoes and bags.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a suede-finished leather-like sheet which solves the above-mentioned problems and does not cause fogging over time.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have reached the present invention. That is, the present invention provides a leather-like sheet substrate made of a nonwoven fabric and an impregnated polyurethane, on at least one surface of which a layer made of a porous polyurethane mixed with a urethane-modified silicone polymer is formed. Is a suede-finished leather-like sheet characterized by being fluffed, and as a method for producing the same, a base layer comprising a non-woven fabric and a porous polyurethane impregnated with the non-woven fabric, and at least one surface thereof comprising a porous polyurethane. In a method for producing a suede-like leather-like sheet having a layer and having a fluffed surface, a polyurethane solution containing a silicone polymer in which a part of a main chain or a side chain is polyurethane is used. Forming a surface layer by wet coagulation of the solution after coating on the base layer; It is a Aid finished leather-like sheet method of manufacturing.

Hereinafter, the present invention will be described in detail. The nonwoven fabric used in the present invention is not particularly limited as long as it has a resilience, strength, and an appropriate thickness in order to express a leather-like texture, but ordinary fibers such as cotton, hemp,
Natural fibers such as wool, regenerated fibers such as rayon and acetate or semi-synthetic fibers, and synthetic fibers made of resins such as polyester, polyamide, polyacrylonitrile, and vinylon. In the case of synthetic fibers, not only single spun fibers but also mixed spun fibers or composite spun fibers may be used. The fiber structure is preferably a non-woven fabric obtained by three-dimensionally entangled fibers. As the polymer constituting the fiber used for the nonwoven fabric, 6-nylon or 6,6-
Polyamides that can be melt-spun, including nylon,
It is at least one polymer selected from melt-spinnable polyesters such as polyethylene terephthalate, polybutylene terephthalate, and cationic dyeable modified polyethylene terephthalate, and polyolefins represented by polypropylene. In addition, sea-island fibers and splittable composite fibers obtained by combining a plurality of polymers may be used. Further, a plurality of fibers may be mixed and used at the time of producing the nonwoven fabric. From the viewpoint of texture, it is preferable to use sea-island type fibers and to remove either the sea component polymer or the island component polymer that constitutes the fiber from the fiber before the product is formed, From the viewpoint of shapeability after application and cost, it is preferable to use fibers made of a homopolymer of polyesters or polyamides.

As the fibrous structure, a woven fabric, a knitted fabric, or a nonwoven fabric is used. However, a nonwoven fabric, a knitted fabric, or a nonwoven fabric is used in view of the ease of forming a uniform nap and the surface smoothness when a coating layer is formed.
Particularly, a three-dimensional entangled nonwoven fabric is preferable. A known method is used as a method for producing the nonwoven fabric. When a nonwoven fabric is used as the fiber structure, the fibers as described above are defibrated with a card, a random web or a cross-wrap web is formed through a webber, and the obtained fiber web is laminated to a desired weight and thickness. A method of obtaining a nonwoven fabric by entanglement of fibers by a needle punching method, a water jet method, an air jet method or the like is preferable. As a method for laminating the nonwoven fabric, a cross wrap method in which the nonwoven fabric is folded in an oblique direction from the balance of the strength and elongation of the warp and weft is preferable. In addition, the entanglement method is preferably a method in which the fibers are entangled with a needle barb.

The obtained nonwoven fabric may be subjected to a surface treatment to improve the smoothness of the surface when polyurethane is applied. As a specific surface treatment method, there are various methods such as a method of pressing with a high-heat calender roll, a method of pressing with a mirror roll cooled after heating the nonwoven fabric, and preferably both ends so that the nonwoven fabric does not change in area due to heat. This is a method of adjusting the thickness to a predetermined thickness by heating and pressing while holding it. Using this method, the surface feeling of the polyurethane layer, the surface feeling of the fibrous nonwoven fabric, and the feeling are extremely good.

The nonwoven fabric obtained by the above treatment is impregnated with a polyurethane solution. Generally, polyurethane is synthesized from a polymer diol such as polyester diol, polyether diol, and polycarbonate diol, a diisocyanate compound, and a chain extender. In the obtained polyurethane, a component derived from the polymer diol is a soft segment component, or a diisocyanate. The component derived from the compound and the chain extender is called a hard segment component, and the hard segment and the soft segment are present alternately to constitute a polyurethane. The soft segments give the polymer elongation, and the hard segments give the polymer strength and prevent plastic flow. As for the polymerization method of the polyurethane, any of known polymerization methods such as a melt polymerization method, a solution polymerization method, and a bulk polymerization method can be used.However, in order to use a solution in the production of a porous structure, it is necessary to use a solvent. The solution polymerization method is preferred from the viewpoint of solubility. Further, a catalyst at the time of polymerization is not always necessary, but catalysts usually used for the production of polyurethane, for example, metal compounds such as titanium tetraisopropoxide, dibutyltin laurate, tin octate, tetramethylbutanediamine, 1,4 diaza ( Tertiary amines such as 2,2,2) bicyclooctane can be used. A method of impregnating the inside of the nonwoven fabric with a solution containing polyurethane and then wet-coagulating or a method of impregnating and then coagulating the polyurethane dispersion liquid is used.

The polyurethane impregnated in the nonwoven fabric is preferably a polyurethane which forms a porous layer when coagulated in a poor solvent. In particular, the number average molecular weight obtained by reacting an alkanediol having 6 to 10 carbon atoms with a dicarboxylic acid or an ester-forming derivative thereof as a soft segment is 500 to 5000, and two or more primary hydroxyl groups in one molecule. The most preferred is a polyurethane obtained by reacting a polyester polymer polyol having an aromatic diisocyanate compound with a low molecular chain extender. In addition, polylactones, polycarbonates, and polyethers are selected from the group consisting of two or more primary hydroxyl groups in one molecule and have a number average molecular weight of 500 to 50.
00 at least one polymer polyol,
A polyurethane obtained by reacting an aromatic diisocyanate with a low molecular chain extender is also preferable.

The alkanediol having 6 to 10 carbon atoms includes 3-methyl-1,5-pentanediol,
Examples thereof include 1,6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. If the alkanediol has less than 6 carbon atoms, the durability, especially the hydrolysis resistance, of the polyurethane will be poor. On the other hand, if the number of carbon atoms is larger than 10, the texture of a sheet obtained when polyurethane is used becomes hard, which may not be preferable. Representative examples of dicarboxylic acids include succinic acid,
Examples thereof include aliphatic dicarboxylic acids such as phthalic acid, glutaric acid, adipic acid, azelaic acid, and sebacic acid, and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid.

The number average molecular weight of the polymer diol used for the polyurethane is preferably from 500 to 5,000. More preferably, it is in the range of 1000-3000. When the number average molecular weight of the polymer polyol is less than 500, when used for a leather-like sheet, the obtained leather-like sheet loses flexibility and lacks balance of texture, which is not preferable. Further, the number average molecular weight of the polymer polyol is 500
If it exceeds 0, it may be difficult to obtain a porous material having a good balance of texture, flexibility, cold resistance, heat resistance and durability. Due to the decrease, the abrasion resistance is reduced, and it is difficult to obtain a product having a well-balanced hydrolytic property.

Examples of the low molecular chain extender include ethylene glycol, propylene glycol, butanediol, and hexanediol. As the aromatic isocyanate, for example, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate,
Examples include phenylene diisocyanate and xylylene diisocyanate. In particular, as a polyol, when a polyether diol such as polymethylpentanediol or polyethylene glycol is used in combination with a polyesterdiol, a fibrous sheet having excellent porous forming properties at the time of texture and coagulation and excellent tensile strength and tear strength can be obtained. This is preferred.

A fibrous nonwoven fabric is impregnated with a polyurethane solution or dispersion obtained by dissolving or dispersing polyurethane in a solvent or dispersant, and then coagulated to obtain a fibrous substrate. If necessary, additives such as a colorant, an antioxidant, a coagulation regulator, and a dispersant are added to the polyurethane solution. The proportion of the impregnated polyurethane solution in the fibrous substrate is preferably at least 10% by weight, particularly 30 to 50% by weight as a solid content in order to give the substrate a soft feel and elastic recovery. If the polyurethane ratio is less than 10%, a smooth surface feeling cannot be obtained, and pores of the dense polyurethane porous layer are not formed, and the feeling becomes hard, which is not preferable. On the other hand, if the polyurethane ratio exceeds 50%, the desired leather-like texture is not obtained due to the resilience of the polyurethane, which is not preferable.

A porous polyurethane layer is formed on a surface layer of a fibrous sheet impregnated with polyurethane. As the method, it is preferable to apply a polyurethane solution to one surface of the fibrous sheet with a certain clearance, and solidify the applied polyurethane in a poor solvent solution of the applied polyurethane to form a porous layer of the applied polyurethane. . The polyurethane solution impregnated in the nonwoven fabric and the polyurethane solution applied to the surface of the polyurethane layer may be simultaneously coagulated.However, the polyurethane solution impregnated in the nonwoven fabric was once coagulated from the smoothness of the polyurethane layer surface after coagulation. Thereafter, a method is preferred in which a polyurethane solution is applied to one surface of the fibrous sheet and solidified to form a porous polyurethane layer on the surface of the fibrous sheet.

The polyurethane applied to the surface layer of the fibrous sheet is produced by the same method from the same raw material as the polyurethane used for impregnating the fibrous sheet, and forms a porous layer upon coagulation. Polyurethane is used. The use of a polyether-based polymer polyol represented by polytetramethylene glycol as its soft segment component is advantageous in that the coagulation regulator used in the present invention exhibits particularly excellent effects in terms of hydrolysis resistance and the like. Is preferred. In addition, polylactone-based, polycarbonate-based, and polyester-based ones may be used. The polyurethane is obtained by reacting these polymer polyols, diisocyanates and low molecular weight chain extenders.

The number average molecular weight of the polymer polyol is 50
0 to 5000 is preferred. When the number average molecular weight of the polymer polyol is less than 500, the surface of the obtained porous layer is hard, the feeling is reduced, and the balance is unfavorable. Further, the number average molecular weight of the polymer polyol is 50
If it exceeds 00, the texture, flexibility, and surface wear resistance are reduced, probably because the urethane group concentration is reduced,
It is difficult to obtain a porous sheet balanced in durability and hydrolysis resistance. Examples of the low molecular chain extender include ethylene glycol, propylene glycol, butanediol, and hexanediol. Examples of the diisocyanate include 4,4'-diphenylmethane isocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate.

The viscosity of the polyurethane solution to be applied is determined from the viewpoint of the degree of sinking of the applied polyurethane solution into the fibrous sheet, the coagulation property of the polyurethane, the fluidity of the applied solution, and the like. Viscosity is 10
It is preferably in the range of ~ 150 poise. More preferably, it is in the range of 20 to 120 poise.

The polyurethane solution to be applied includes a coloring agent,
Additives such as light stabilizers and dispersants may be added according to the purpose. Further, a coagulation regulator is added for controlling the pore diameter of the porous body after coagulation. In the present invention, as a coagulation controlling agent for controlling the pore shape, a coagulation controlling agent in which a part of a silicone side chain is polyurethane is added. Further, another coagulation regulator may be used in combination.

In general, a coagulation controlling agent comprising a silicone compound has an effect of making the pore diameter of a porous structure small and uniform during wet coagulation of polyurethane, and when used as a coagulating controlling agent for polyurethane applied to the surface of a leather-like sheet, The sheet has been widely used because of its features of obtaining a uniform crease feeling, physical strength due to a uniform polyurethane structure, and good surface smoothness. On the other hand, when the silicone-based coagulation regulator is present in the porous polyurethane layer, the silicone-based coagulation regulator bleeds over time even if the polyurethane is completely solidified. The silicone-based coagulation regulator causes bleeding of polyurethane oligomers on the surface at the same time, causing fogging and causing a change in surface color tone and loss of luxury.

The present inventors use a silicone-based coagulation control agent in which a part of the silicone main chain or side chain is made into polyurethane, thereby keeping the coagulation control agent in the porous polyurethane layer, In addition, it was found that a suede-like leather-like sheet in which the color tone of the surface did not change was obtained by preventing the phenomenon of bleeding of the oligomer of polyurethane on the surface.

In order to make a part of the silicone main chain or a side chain into a polyurethane, a silicone compound having a reactive organic functional group is reacted with an organic polyisocyanate under the condition that one or more isocyanate groups are excess, and the remaining isocyanate is reacted. A method in which a polyol having at least one active hydrogen group is reacted with the group in an organic solvent is preferable. A silicone-based coagulation regulator in which a part of the silicone main chain or side chain is made into a polyurethane is a silicone compound having a reactive organic functional group and an organic polyisocyanate. Can be easily obtained by reacting at a functional group ratio in which at least one is excessive.

Known silicone oils can be used as the silicone compound having a reactive organic functional group. Specific examples include silicone oils represented by the following chemical formula, but are not limited to the following formulas as long as desired effects can be obtained.

Amino-modified silicone oil

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Epoxy-modified silicone oil

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Alcohol-modified silicone oil

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Mercapto-modified silicone oil

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Carboxyl-modified silicone oil

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Specific examples of the organic polyisocyanate to be reacted with these silicone compounds include aromatic, aliphatic, and alicyclic compounds such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, and xylylene diisocyanate. One. After reacting the silicone compound with the organic polyisocyanate, it is preferable to react the resulting isocyanate group-containing compound with a polyol having one or more active hydrogen groups. Specific examples include, for example, polymer diols used when synthesizing polyurethane, and typical examples thereof include polyether glycols such as polypropylene glycol and polyethylene glycol, polyester glycols, and the like. -1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol and the like are also included. This reaction is preferably performed in an organic solvent for reasons such as the reactivity of the organic polyisocyanate group,
The preferred organic solvent used for this includes dimethylformamide, but is not particularly limited as long as it is inert to each reaction raw material. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone,
Examples include tetrahydrofuran, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, isopropyl alcohol, ethyl cellosolve, hexane, toluene, xylene and the like. Other known organic solvents may be used.

The urethane-modified silicone polymer thus obtained is mixed with a polyurethane solution applied to the surface of the fibrous sheet. The amount of the coagulation regulator to be added is not particularly limited as long as the applied polyurethane forms a porous layer after coagulation. The range in which the porous layer is formed is preferably 3 μm or less in a section of the polyurethane after coagulation where the pore diameter is close to the surface, and 5 to 30 μm in a section close to the fibrous layer far from the surface. Indicates that a porous layer is formed. In addition, the pore diameter of the porous portion referred to here means a mean value of the maximum width of each pore of the porous portion obtained by taking a micrograph of the coagulated polyurethane from the cross-sectional direction and obtaining from this photograph. It does not mean. If the pore size is larger than the preferred range, the abrasion of the polyurethane layer is reduced, and the crimping feeling is unfavorable because the crimping feel resembles the way cardboard is folded. In particular, when the pore diameter at a portion away from the surface and close to the fibrous layer is larger than 30 μm, the polyurethane layer is crushed at the time of post-processing, the specific gravity is increased, and the crimp and the texture are deteriorated.
Even when it is smaller than m, the specific gravity becomes too high and the texture becomes hard, which is not preferable. Therefore, the preferable range of the addition amount is in the range of 0.3 to 20% by weight, more preferably in the range of 0.5 to 12% by weight of the solid content of the polyurethane forming the porous layer.

The applied polyurethane solution is coagulated with a non-solvent of polyurethane and solidified to obtain a porous polyurethane layer. Although water is used as the non-solvent, coagulation may be performed in an aqueous solution in which a polyurethane solvent is mixed in order to reduce the pore size of the porous polyurethane layer. A preferable coagulation condition is a method of coagulation in an aqueous solution mixed with an organic solvent of 5 to 50% by weight from the viewpoint of concentration control and coagulation speed.

The thickness of the porous polyurethane layer is preferably 10 μm after solidification in terms of surface wear resistance and feeling.
It is in the range of 0 μm to 600 μm. More preferably, the thickness is in the range of 200 to 400 μm.

The surface of the obtained fibrous sheet having a porous polyurethane layer is ground to expose the porous structure of the porous polyurethane layer and fluffed to obtain a suede-like leather-like sheet. The method of grinding the surface using a sandpaper is industrially excellent. The sandpaper used for the method is 80-400 mesh, and the degree of grinding is the surface of the porous polyurethane layer. Is preferably removed in a thickness of about 10 to 150 μm. The surface of the suede-finished leather-like sheet thus obtained may be subjected to coloring, embossing or the like, if necessary.

[0035]

EXAMPLES Next, the embodiments of the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Parts and percentages in the examples relate to weight unless otherwise specified.

Example 1 Nylon and polyethylene were mixed at a tip / tip ratio of 50/50 and spun with an extruder to spin sea-island cross-section structural fibers (nylon is an island component, polyethylene was a sea component) and stretched. A 4 denier cut short fiber was obtained, and this fiber was entangled to obtain a nonwoven fabric. Polyurethane (polymer diol having an average molecular weight of 2,000 comprising polymethylpentane adipate and polyethylene glycol,
After impregnating a solution of 4′-diphenylmethane diisocyanate and butanediol (polyurethane) in dimethylformamide (hereinafter referred to as DMF) and performing wet coagulation, the fiber is dissolved in a solvent (toluene) that does not dissolve the island component in the fiber but can dissolve the sea component. 450g /
m ² , thickness 1.3 mm, ratio of polyurethane to fiber is 5
A 5/45 substrate layer was obtained. The fineness of the monofilament of the obtained ultrafine fibers of the fibrous substrate is 0.06 denier,
And had a soft texture.

Polyurethane using polytetramethylene glycol as the main component of polyol, hexamethylene diisocyanate as the isocyanate component, and ethylene glycol as the chain extender was prepared using dimethylformamide (DM
F), a solid content of 17% and a viscosity of 40 P (30
C), a coagulation regulator obtained by reacting terminal aminopropylpolymethylsiloxane having an amino group as a reactive functional group with hexamethylene diisocyanate, and further reacting terminal diisocyanate with polypropylene glycol was added. The addition amount of the coagulation regulator was 3 parts with respect to 100 parts of the polyurethane solid content. In addition, 10 parts of a black pigment was added and mixed. This polyurethane solution was coated on the fibrous substrate in an amount of 1000 g / m 2.
The mixture was applied in ^2, and poured into a mixed solution of DMF / water = 30/70 at 35 ° C. to coagulate the polyurethane to obtain a sheet having a 450 μm thick porous polyurethane layer on a fibrous substrate. The surface of this sheet was ground with a 200-mesh sandpaper to scrape off the surface of the porous polyurethane layer of 50 μm, to give a sheet having suede-like fluff. The leather-like sheet was measured at 90 ° C. for 10 days to measure the change with time on the surface in order to promote cloudiness, but no change in color tone was observed. A photograph of the cross section of the porous layer portion in the sheet thickness direction was taken with a microscope, and the average value of the hole width was determined. The surface portion was approximately 2 μm, and the portion close to the fiber base layer was approximately 15 μm. It turned out that it became smaller as it approached the part.

Example 2 The non-woven fabric used in Example 1 was used, and the non-woven fabric was made of polyurethane (polymer diol composed of polymethylpentane adipate and polyethylene glycol having an average molecular weight of 2,000, 4,4'-diphenylmethane diisocyanate and butanediol). (Polyurethane) in DMF. Next, a polyurethane solution having a solid content of 20% and a viscosity of 60 poise (30 ° C.) obtained by using DMF as a solvent with polytetramethylene glycol as a polyol component was prepared by adding a reactive organic functional group of a polysiloxane main chain to an organic polyisocyanate. The reaction was carried out using hexamethylene diisocyanate, and 3 parts of a coagulation regulator obtained by reacting the remaining isocyanate groups with polypropylene glycol were added to 100 parts of polyurethane solids, and 10 parts of a black pigment was further added and mixed. . The polyurethane solution was applied onto the fibrous substrate at a clearance of 1.6 mm with an application amount of 1
000 g / m ² and DMF / water at 35 ° C. = 30
/ 70, and coagulated the polyurethane impregnated in the nonwoven fabric layer and the coated polyurethane simultaneously. Thereafter, after removing polyethylene constituting the fiber, polyurethane is applied to the surface of the fibrous base material by a gravure method, and the surface is heat-treated at 180 ° C. with a calender roll to give a glossy feeling. 500
A sheet having a μm porous polyurethane layer was obtained. The surface of this sheet was ground with a 200-mesh sandpaper to scrape off the surface of the porous polyurethane layer of 50 μm, to give a sheet having suede-like fluff. The leather-like sheet was measured at 90 ° C. for 10 days to promote the cloudiness, and no change in gloss was observed. A photograph of the cross section of the porous layer portion in the sheet thickness direction was taken with a microscope, and the average value of the hole width was determined. The portion close to the fiber base layer was approximately 15 μm, and it became smaller as approaching the surface. There was found.

COMPARATIVE EXAMPLE 1 A polysiloxane component was added to a polyurethane solution having a solid content of 17% and a viscosity of 40 poise (30 ° C.) containing polytetramethylene glycol as a main component of polyol and DMF as a solvent in the base layer obtained in Example 1. , A silicon-based solidification regulator and a black pigment were mixed in the same amounts as in Example 1, and applied on the fibrous substrate at an application amount of 1000 g / m ² ,
The mixture was poured into a mixed solution of DMF / water = 30/70 at a temperature of ° C to coagulate the polyurethane. The surface was ground with sandpaper in the same manner as in Example 1, and the surface condition was observed at 90 ° C. for fogging. After 3 days, the surface became whitish, and the surface was wiped off with a cloth. A difference in glossiness was clearly observed where no wiping was performed, and it was confirmed that clouding due to migration occurred. Take a photograph of the cross section of the porous layer part in the sheet thickness direction with a microscope and find the average value of the hole width,
It was found that the portion near the fiber substrate layer was about 10 μm, and became smaller as approaching the surface.

Comparative Example 2 The base layer obtained in Example 1 was composed of polytetramethylene glycol as the main component of polyol, DMF as a solvent, a solid content of 17%, a viscosity of 40 poise (30 ° C.), and a polyurethane solution containing only black pigment. Was mixed and applied on the fibrous substrate at a coating amount of 1000 g / m ² with a clearance of 1.6 mm and poured into a mixed solution of DMF / water = 30/70 at 35 ° C. to coagulate the polyurethane. The texture of the obtained sheet was harder than that of the natural leather and the sheet obtained in Example 1, and the surface had dents of about 1 mm in diameter in some places, resulting in poor surface feeling. When the surface of such a sheet was ground with sandpaper, a uniform fluffy state could not be obtained, and only a mottled and cheap suede-like sheet could be obtained. A photograph of a cross section of the porous polyurethane layer portion in the sheet thickness direction was taken with a microscope, and the average value of the width of the holes was determined. The surface portion was about 10 μm, and the portion close to the fiber base layer was about 50 μm. .

[0041]

The suede-like leather-like sheet obtained by the present invention has a feature similar to that of natural leather and a small change in color tone due to aging.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 75/04 C08L 75/04 83/04 83/04 F term (Reference) 4F055 AA02 AA27 BA12 BA16 DA07 DA10 EA24 EA30 FA15 FA27 GA01 GA22 4F100 AK04 AK48 AK51A AK51B AK51C AK52B AK52C AL06B AL06C BA02 BA03 BA06 BA10B BA10C BA13 DG15A DG16B DG16C DJ00B DJ00C EH462 EJ82A GB74 GB90 HB22B HB22C 4J002 AB00W AD031 BB121 BE061 BG101 CF001 CF061 CK022 CK032 CK042 CL001 CL011 CL031 CP033 FA092 GF00 GK01

Claims (2)

[Claims] 1. A layer made of porous polyurethane mixed with a urethane-modified silicone polymer is formed on at least one surface of a leather-like sheet substrate made of a nonwoven fabric and an impregnated polyurethane, and a surface of the layer is formed. Suede-like leather-like sheet characterized by having a fluff. 2. A suede-like leather having a substrate layer comprising a nonwoven fabric and a porous polyurethane impregnated therein, having at least one surface layer comprising a porous polyurethane, and having a fuzzed surface. In the method for producing a sheet, a solution of a polyurethane containing a silicon polymer in which a main chain or a part of a side chain is partially polyurethane is applied onto the base layer, and then the solution is wet-solidified to form the surface layer. A method for producing a suede-finished leather-like sheet, characterized by forming: