JPS6364549B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application] The present invention relates to the processing of nonwoven fabrics for base materials of artificial leather. More specifically, the present invention relates to the processing of nonwoven fabrics that have excellent flexibility and are suitable for producing stiff artificial leather. [Prior art] Artificial leather consists of a base made of entangled nonwoven fabric impregnated with an elastic polymeric substance, and a silver-plated product with a coating layer of a polymeric substance applied to the surface of the base, or a fiber napped layer is formed by buffing the base. Made from soft suede. As a means to make the texture of artificial leather soft, a method is proposed in which nonwoven fabric is treated with silicone resin in advance and then impregnated with a polymeric substance to prevent adhesion between the fibers and the impregnated polymeric substance (Japanese Patent Publication No. 45-33797). (No. Publication), a nonwoven fabric is impregnated with a sizing polymeric substance that uses a different solvent from the impregnated polymeric substance, and a part of the nonwoven fabric fibers is covered or a part of the fiber space is filled, and an elastic polymeric substance is impregnated. After coagulation, the adhesive polymeric substance is removed to form voids between the fibers and the elastic polymeric substance (for example, Japanese Patent Publication No. 18745-1970, Japanese Patent Application Laid-Open No. 109697-1987).
etc. have been proposed. [Problems to be solved] However, with these known methods, the chemical structure of the nonwoven fabric fibers has poor affinity with the adhesive polymer, and a sufficient coating effect cannot be obtained, or the processing liquid Due to its wetting properties with the fibers, it has the disadvantage that it is difficult to adhere to the surface of the nonwoven fibers and to sufficiently exhibit the mold release effect between the fibers and the impregnated polymeric material. Therefore, the artificial leather substrates obtained by these known methods have a hard feel, and even when bent, they have a buckled and wrinkled shape. The inventors of the present invention have conducted intensive studies to overcome these drawbacks and produce artificial leather that is firm and flexible, and as a result, they have arrived at the present invention. [Object of the invention] The present invention provides a processed nonwoven fabric for a base material that is flexible, has good elasticity, has a good appearance, and is suitable for producing artificial leather that has excellent secondary processability and wearability. . [Structure of the Invention] The present invention is a nonwoven fabric suitable as a base fabric for artificial leather, in which a sizing polymer substance and a fatty acid amide represented by the following formula (1) are attached to nonwoven fabric fibers. . R ₁ CONR ₃ (R ₂ NR ₃ ) _o OCR ₁ ...(1) (However, R ₁ = Alkyl group with 12 to 28 carbon atoms R ₂ = Alkylene group with 1 to 8 carbon atoms R ₃ = H or intermolecular Cross-linking (number of n=1 to 8) [Means for solving the problem] As described above, the present invention is a nonwoven fabric in which a sizing agent polymer substance and the fatty acid amide are attached to nonwoven fabric fibers. The nonwoven fabrics used in this process are made of natural fibers, recycled fibers, or synthetic fibers, but preferably synthetic fibers such as polyester fibers, polyamide fibers, polyolefin fibers, acrylic fibers, etc. are used as the main fibers. It is a fiber-entangled nonwoven fabric made by making a web by a dry method, or by a wet method by dispersing it in water and making a web by a paper-making method, and then entangling it by means such as a needle punch method or a fluid jet method. These fiber-entangled nonwoven fabrics are preferred in terms of their suitability as substrates for artificial leather. The adhesive polymeric substance to be attached to the nonwoven fabric is preferably a polymeric substance that dissolves in a solvent different from the solvent or dispersant for the elastic polymeric substance to be impregnated in a later step, such as the solvent or dispersant for polyurethane or natural or synthetic rubber. , such as polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxymethyl cellulose (Na salt), polyvinyl acetate,
Preferred are polymeric sizing agents that are soluble in water, alcohols, or acetone, such as vinyl acetate-ethylene copolymer, starch, polyester, modified starch, and modified cellulose. Particularly preferred are water-soluble sizing polymers, such as polyvinyl alcohol polymers, carboxymethyl cellulose, starch, and the like. Further, the amount of the adhesive polymeric material attached to the nonwoven fabric on the fibers is 2 to 40% by weight. If the amount of adhesion is small, the elastic polymer substance impregnated in the later process will adhere to the intersections of the fibers, fixing the fibers, resulting in a hard texture, or a surface that is not suitable for processing in the later process. Problems arise, such as not being able to obtain a smooth nonwoven fabric, and furthermore, the shape of the nonwoven fabric changing during processing in subsequent steps. on the other hand,
If the amount of adhesion is large, migration that occurs during coagulation of the sizing agent polymer substance will result in non-uniform adhesion, which will also have an unfavorable effect on the performance of the artificial leather. Next, the fatty acid amide used in combination has, for example, one having the following chemical structure. C ₁₅ H ₃₁ CONH (CH ₂ NH) ₆ OC ₁₅ H ₃₁ (1) C ₁₇ H ₃₅ CONH (C ₄ H ₈ NH) ₃ OC ₂₃ H ₄₇ (2) C ₁₃ H ₂₇ CONH (C ₆ H ₁₂ NH) ₄ O C ₁₃ H ₂₇ (3) It is preferable to use these fatty acid amides in a dissolved or dispersed state in water or alcohol, or to dissolve the dispersion in water by heating and use the fatty acid amide in the form of oil-in-water droplets. Further, the amount of fatty acid amide attached to the fibers to be attached to the nonwoven fabric is 0.5 to 13% by weight. If the amount of adhesion is small, the effect of preventing adhesion between the fiber and the elastic polymer substance impregnated in the subsequent process will be small. Furthermore, even when the surface of the nonwoven fabric is smoothed or the thickness is made uniform by hot pressing or the like, the workability is poor and a clean surface cannot be obtained. On the other hand, if the amount of adhesion is large, the adhesive will fall off when the adhesive polymer solidifies, resulting in a loss. As for the method of attaching the sizing polymer substance and the fatty acid amide to the nonwoven fabric, each may be applied in separate treatments, but a solution or dispersion of the fatty acid amide is added to the solution or dispersion of the sizing polymer substance. When mixed, it is preferable to carry out simultaneous processing in a mixed system unless aggregation of any substance occurs. The treated nonwoven fabric is subjected to a coagulation process to fix deposits to the fibers. The coagulation method can be carried out by a normal method that does not require any special method, but in order to adhere the fatty acid amide relatively uniformly to the fiber surface, it is necessary to
It is preferable to add a heating treatment at about 100 to 150° C. before the final nonwoven fabric processing step. If a nonwoven fabric to which a sizing agent polymer substance and a fatty acid amide are attached is heat-treated or pressurized while being brought into close contact with a roll or belt surface having a smooth surface as necessary, the non-woven fabric will have a smooth surface and will have an uneven thickness. It is possible to create a processed nonwoven fabric with less. Next, embodiments of the present invention will be specifically explained.
The present invention is not limited to these examples. Note that parts and percentages in the text refer to weight unless otherwise specified. Examples 1 to 6 A random web of polyethylene terephthalate (hereinafter referred to as PEH) fiber with a fineness of 1.3 denier was made, and four sheets were laminated and needle punched to make an entangled nonwoven fabric with an average basis weight of 285 g/m ² . On the other hand, as a sizing agent composition for gluing the fibers of the entangled nonwoven fabric, 4 parts of polyvinyl alcohol with a degree of saponification of 98% and a fatty acid amide represented by the following formula were used. A 10% fatty acid amide emulsion dispersion was blended in the proportions shown in Table 1 and dissolved and dispersed in water to prepare a composition.

[Table] Squeeze this adjusted composition liquid to the above entangled nonwoven fabric to a squeezing rate of approximately 200%, dry most of it in a hot air dryer at 120°C, and then dry it in a heated drum with a mirror surface. The surface was brought into contact with a dryer to complete drying and a glued nonwoven fabric with a smooth surface was obtained. Next, the glued nonwoven fabric was fully impregnated with an impregnating solution containing 18% polyurethane of the polyester soft segment in dimethylformamide (DMF) to which a coagulation regulator and a coloring agent were added. After applying a surface coating layer with a thickness of 0.8 mm, it was immersed in a DMF aqueous solution to solidify, followed by dissolving and removing the polyvinyl alcohol in hot water at 88-90°C, and drying.
The back side of the sheet obtained by impregnating and applying polyurethane was sliced to obtain a sheet having a thickness of 1.7 mm. The texture of this sheet-like object when you hold it,
We observed the sensorial performance that is important for a product, such as the creases caused by folding the sheet with the surface coating layer on the inside, and the fuzzy, uneven feel of the surface caused by pulling the sheet 10% in both directions, as well as the adhesion between the fiber and polyurethane. The results are shown in Table 2.

[Table] In other words, the product of the present invention has particularly excellent sensory performance because the fibers are well separated from the polyurethane applied afterwards, and the product is a sheet-like product that has been finished with surface coloring, embossing, etc. When processed into shoes, they became comfortable shoes. Example 7 A cross-lap web made by blending 50 parts of PET non-shrinkable fiber with a fineness of 0.7 denier and 36 mm and 50 parts of PET shrinkable fiber with a fineness of 1.5 denier and 51 mm was needle-punched to give an average basis weight of 170 g/m ² An entangled nonwoven fabric was prepared, and then immersed in hot water at 95°C for shrinkage treatment to produce a shrink entangled nonwoven fabric with an area shrinkage rate of 46%. On the other hand, using 7 parts of polyvinyl alcohol and a fatty acid amide shown by the following formula, 7 parts of fatty acid amide 15% emulsified dispersion and 86 parts of water
A composition solution was prepared by blending the ingredients in the following proportions: This adjusted size composition liquid was impregnated into the above-mentioned shrinkable nonwoven fabric, and the liquid was squeezed out to produce a shrinkable nonwoven fabric containing the size composition liquid with an adhesion rate of 145%, and then the surface was brought into contact with a hot drum dryer with a smooth surface. After drying, a glued nonwoven fabric with a smooth surface was obtained. Next, polytetramethylene ether/polycaprolactone soft segment mixed polyurethane
The above glued nonwoven fabric was impregnated with an impregnating solution containing a 18% DMF solution with a coagulation regulator and a colorant added, and the DMF40
% aqueous solution, followed by dissolving and removing the polyvinyl alcohol in hot water at 88-90°C, and drying. The sheet-like material obtained in this way has a firm and flexible feel similar to that of natural cowhide leather, and the fibers and the impregnated polyurethane are well separated and the the intersection of
The joints were also not sealed with polyurethane. Furthermore, the fatty acid amide remains without being completely removed, which also has a good effect on the texture. When a buffing finish was applied to both sides of this sheet-like product, a velor-like product was obtained. On the other hand, a polyurethane sponge layer is placed on the smooth side and colored.
When finished by stamping, a cap-like silver-plated product was obtained. Example 8 A needle-punched entangled nonwoven fabric with a basis weight of approximately 210 g/m ² made by blending 70 parts of nylon-6 fiber with a fineness of 1.5 denier and 30 parts of PET shrinkable fiber with a fineness of 1.5 denier was soaked in hot water at 95°C. A shrinkage-entangled nonwoven fabric with an area shrinkage rate of 35% was produced by immersing it in water and performing a shrinkage treatment. This shrinkable nonwoven fabric was impregnated with the glue composition liquid prepared in Example 7, squeezed to produce a shrinkable nonwoven fabric containing the glue composition liquid with an adhesion rate of 140%, and dried to obtain a glued nonwoven fabric. A sheet-like product obtained by subjecting this pasted nonwoven fabric to the same urethane treatment as in Example 7 had a soft feel similar to that of natural cowhide (glove leather).

Claims (1)

[Scope of Claims] 1. A nonwoven fabric for artificial leather comprising a nonwoven fabric, a sizing agent present on the surface of fibers constituting the nonwoven fabric, and a fatty acid amide represented by the following formula (1). R ₁ CONR ₃ (R ₂ NR ₃ ) _o OCR ₁ ...(1) (However, R ₁ = Alkyl group with 12 to 28 carbon atoms R ₂ = Alkylene group with 1 to 8 carbon atoms R ₃ = H or intermolecular Cross-linking (n = number of 1 to 8) 2 The glue polymer substance is polyvinyl alcohol,
The nonwoven fabric for artificial leather according to claim 1, which is at least one selected from partially saponified polyvinyl alcohol, carboxymethyl cellulose (Na salt), polyvinyl acetate, vinyl acetate-ethylene copolymer, and starch. 3. The adhesion amount of the sizing polymer substance and fatty acid amide to the nonwoven fabric fibers is 2 to 2.
40% by weight, and the fatty acid amide content is in the range of 0.5 to 13% by weight. The nonwoven fabric for artificial leather according to claim 1. 4 Add the following formula (1) to the glue polymer substance solution or dispersion.
1. A method for producing a nonwoven fabric for artificial leather, which comprises impregnating a nonwoven fabric with a solution or dispersion of a fatty acid amide represented by the following formula and solidifying the composition to adhere the composition to the nonwoven fabric fibers. R ₁ CONR ₃ (R ₂ NR ₃ ) _o OCR ₁ ...(1) (However, R ₁ = Alkyl group with 12 to 28 carbon atoms R ₂ = Alkylene group with 1 to 8 carbon atoms R ₃ = H or intermolecular cross-linking n=number of 1 to 8)