JPH0192482A - Production of soft leather like sheet article - Google Patents

Abstract

PURPOSE: To obtain a highly flexible leather sheet-like product by treating a base fabric of synthetic fiber with a chemical agent or organic solvent followed by setting a water-soluble polymer on the resultant fabric which is then impregnated with a water-miscible organic solvent solution of a polyurethane elastomer followed by wet coagulation. CONSTITUTION: This leather sheet-like product further improved in flexibility is obtained by the following process: a base fabric of synthetic fiber (esp. predominant in polyester fiber) is treated with a chemical agent such as an anionic or nonionic surfactant or an organic solvent such as an alcohol (e.g. ethanol), esp. dimethylformamide to remove treatment agent(s) left in the base fabric; a water-soluble polymer (e.g. PVA) is then set on the resultant fabric which, in turn, is impregnated with a water-miscible organic solvent solution of a polyurethane elastomer followed by coagulation in water or water containing <=20 wt.% of a water-miscible organic solvent. Thus, pretreatment of the base fabric with the chemical agent or the like improves the affinity of the fiber for the water-soluble polymer, effecting marked improvement of the flexibility of the final product.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a leather-like sheet material, and more specifically, a porous wet coagulated product of polyurethane elastomer is applied to a base fabric mainly composed of synthetic fibers. The present invention relates to a method for producing a filled leather-like sheet material with improved flexibility.

[Conventional technology]

It is well known that a base fabric such as a non-woven fabric is impregnated with a solution of a polyurethane elastomer in a water-miscible organic solvent, wet coagulated, washed with water and dried to obtain a leather-like sheet. It is also known that the flexibility of the resulting sheet-like product can be improved by temporarily fixing the base fabric with a water-soluble polymeric substance such as polyvinyl alcohol before the process.

This temporary fixation using a water-soluble polymeric substance creates voids between the fibers constituting the base fabric and the polyurethane elastomer (binder), allowing the fibers to be freely displaced or deformed to some extent by bending, etc. This aims to improve the flexibility of sheet-like materials.

However, with the method of simply fixing the base fabric with a water-soluble polymer substance, the affinity between the fibers and the water-soluble polymer substance is poor, and the water-soluble polymer substance may stain the surface of the base fabric during drying. It has the disadvantage that a sufficient coating effect cannot be obtained due to thinning, and the effect of treatment with a water-soluble polymer substance is not fully expressed.

As a method to improve these drawbacks, Japanese Patent Laid-Open No. 61-18
Publication No. 6570 describes a glue made exclusively for polyvinyl alcohol! ] W 11/jM amide is added to the base fabric to further complete the voids between the fibers constituting the base fabric and the polyurethane elastomer, or to prevent migration of water-soluble polymeric substances. Although various proposals have been made, there is currently no method that is completely satisfactory.

[Problem that the invention seeks to solve]

The present inventors addressed the problems of the prior art as described above, and created a leather-like sheet by fixing a water-soluble polymer substance to a base fabric mainly composed of synthetic mNA, impregnating it with a polyurethane elastomer, and wet-coagulating it. As a result of a consensus study on how to maximize the effect of applying a water-soluble polymer substance in the production of fabrics, we found that prior to applying the water-soluble polymer substance, the base fabric was treated with chemicals or organic substances. We have discovered that treatment with a solvent surprisingly contributes to improving flexibility, and have completed the present invention based on this knowledge.

[Means for resolving issues]

That is, in the present invention, a base fabric mainly composed of synthetic fibers is treated with a chemical or an organic solvent, and after the treatment agent is removed, a water-soluble polymer substance is fixed thereon, and then a solution of a polyurethane elastomer in a water-miscible organic solvent is impregnated. This is a method for producing a flexible leather-like sheet material, which is characterized by wet-coagulating the product in an aqueous medium, washing with water, and drying it.

In the present invention, the synthetic FIN Hm includes polyolefin fibers, polyamide fibers, polyester fibers, etc., and polyamide fibers and polyester fibers are particularly preferred.

In addition, the base fabric mainly composed of synthetic fibers generally refers to woven fabrics, knitted fabrics, raised products thereof, or non-woven fabrics containing 70% by weight or more of synthetic fibers, but non-woven fabrics are preferred in terms of obtaining a leather-like texture. Most preferred.

Although there are no particular restrictions on the basis weight of the base fabric, the change of heart of the constituent fibers, etc., the flexibility improvement effect of the method of the present invention, especially when considering the sensory effects such as texture and touch, etc. has a basis weight of 50 to 600g/1T12, especially 10
0 to 400 g/m2 and the constitution at m (7) is most prominently exhibited in the case of a base fabric having an electric potential in the range of 0.1 to 8 d, particularly 0.1 to 2 d.

In the present invention, a base fabric mainly composed of synthetic fibers as described above is treated with a chemical or an organic solvent. Examples of the agents used here include nonionic surfactants such as fatty acid metal salts, alkylbenzenesulfone polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and fatty acid jetanolamide. Organic solvents include alcohols such as methanol and ethanol, acetone, ethane tetrachloride, benzene, toluene, and dimethylformamide. In particular, dimethylformamide and dimethylacetamide, which are commonly used as solvents for polyurethane elastomers, are used as solvents. It is preferable from the industrial point of view of recovery.

As for the method of treating the base fabric with these chemicals or organic solvents, in the case of chemical treatment, 1 to 10 g of the above-mentioned chemicals are used.
/l of the aqueous solution, and to further enhance the effect, add a small amount of alkali (usually about 1 g/l), and immerse the base fabric in the aqueous drug solution or the above-mentioned solvent for a certain period of time.
You can soak it in a mangle or the like.

Furthermore, the treatment with the aqueous chemical solution or the solvent is more effective at high temperatures than at low temperatures, and the treatment time can be shortened, which is more preferable.

After the above-mentioned treatment, it is necessary to remove the chemicals or solvents by thoroughly washing the base fabric with water or the like in order to obtain the flexible sheet-like article that is the object of the present invention.

Next, a water-soluble polymer substance is fixed to the treated cloth, and the water-soluble polymer substances used here include polyvinyl alcohol, water-soluble starch, methyl cellulose, carboxymethyl cellulose, sodium polyacrylate, etc.
It is a water-soluble substance that can extubate and fix the base fabric, and is insoluble in the solvent of polyurethane elastomer. It is preferable that the water-soluble 1-6 molecule substance has a degree of elegance in an aqueous solution of 5 to 20% because it has excellent permeability into the base fabric and also allows easy adjustment of the solid El to the base fabric. . Generally speaking, the amount of water-soluble polymer substances that adhere to the base fabric is 5% of the weight of the base fabric.
~30%. If the amount is less than 5%, the softening effect will be small, and even if the adhesion amount is higher than 8J)%, the flexibility will not be further improved, which is disadvantageous in terms of the quality of the sheet-like material, and furthermore, from the viewpoint of photographic efficiency and economy. be. In the method of the present invention, the adhesion of water fB-prone molecular substances to the base fabric is achieved by impregnating the base fabric with an aqueous solution of a water-soluble polymeric substance in accordance with a conventional method, and then squeezing the water to obtain the desired impregnation fB.
1 (amount of adhesion), then 80 to 150
This is done by heating and drying at °C.

Treated with a chemical or organic solvent as described above.

Next, it is applied to a base fabric to which a water-soluble polymer substance is fixed.

Subsequently, a sheet-like product is prepared by impregnating a solution of a polyurethane elastomer in a water-miscible organic solvent, wet coagulating, washing with water, and drying. This step can also be carried out according to a conventional method. That is, as a solution of a polyurethane elastomer in a water-miscible organic solvent (hereinafter referred to as a polyurethane elastomer solution), a polyester type, polyether type, polyester/ether type, or polycaprolactone type polyurethane elastomer can be prepared using a water-miscible organic solvent such as dimethylformamide, middle acetamide, etc. What is used is dissolved in a solvent to a concentration of 10 to 25% by weight, preferably 15 to 20% by weight. Incidentally, colorants such as pigments and dyes, fine particle fillers, coagulation regulators, flame retardants, and the like may be added to the polyurethane elastomer solution.

The degree of impregnation of the base fabric with the polyurethane elastomer solution varies depending on the intended use of the sheet, but generally the ratio of the base fabric (I:A fiber) to the solid content of the polyurethane elastomer is 80 to 7010 (weight ratio). It is appropriate to keep it within the range of .

Wet coagulation of the substrate impregnated with the polyurethane elastomer solution is carried out preferably using water or water containing up to 20% water-miscible organic solvent as the coagulation medium at 30-50°C.
This is done by soaking for 20 minutes.

After this wet coagulation is completed, the resulting sheet material is successively washed with water while being passed through a squeezing roll to sufficiently elute the oral solvent or water-soluble polymeric substance, and then heated and dried according to a conventional method to achieve the desired purpose. A leather-like sheet material is obtained.

〔Effect of the invention〕

Thus, according to the method of the present invention, compared to the conventional method of simply fixing a water-soluble polymer substance to a base fabric, a much greater softening effect can be achieved with the same amount of fixation.

It is possible to easily produce a leather-like sheet material with excellent soft feel and texture, which cannot be achieved by conventional methods.

The reason why such a remarkable effect can be obtained by the method of the present invention is that the affinity between the fibers constituting the base fabric and the water-soluble polymer substance is improved by treating the base fabric with a chemical or an organic solvent. This is thought to be due to the water-soluble polymer substance being able to uniformly and effectively cover the surface of the 3 fibers. It is not clear what is the reason for the above-mentioned improvement in affinity, but when the base fabric is treated with chemicals or organic solvents, oils, etc. on the surface of the synthetic fibers that make up the base fabric are likely to fall off. Although this is presumed to be one reason, it is also possible that other changes have occurred in the fiber. In order to improve the affinity between the fibers that make up this base fabric and the water-soluble polymeric substance, an affinity improving agent or a wettability improving agent may be applied to the base fabric in advance, or it may be added to an aqueous solution of the water-soluble polymeric substance. However, the method of the present invention does not have the above-mentioned drawbacks and easily improves flexibility. This is an excellent method in that it greatly improves this.

The leather-like sheet material of the present invention can be used as it is for various purposes, but it can also be subjected to additional processes such as grain processing, embossing, dyeing and finishing, or for making suede. By applying the buffing process, etc., a leather substitute that is unprecedentedly inexpensive and has a good sense of fullness and softness can be provided.

〔Example〕

The present invention will be explained in more detail below using Examples. In each example, as an index of the flexibility of the sheet material, JIS L 1 09 6 Bending Repulsion Note Test Method A was used.
The Gurley bending resistance measured by the Gurley method was used (the smaller the value, the more flexible it is). Moreover, the strength and elongation were measured according to JIS K-6550.

Example 1 Shrinkable polyethylene terephthalate short fibers with a fineness of 1.5 d%, a fiber length of 51 mm, a number of crimps of 16 threads/inch, and a drainage shrinkage rate of 20% were formed into a web using a carding machine and a cross-lapper machine, and then using a No. 40 needle. Needling was performed from the top and bottom at a density of 800 punches/cm2, respectively, to produce a nonwoven fabric with a height of 1.7 mm and a weight of 200 g/m2.

This non-woven fabric was soaked in 80°C hot water fl, an 80″C hot water bath containing 5 g/l polyoxyethylene (8 mol ethylene) nonyl phenyl ether, and 5 g/l polyoxyethylene (8 mol ethylene) nonyl phenyl ether. 80°C hot water bath containing phenyl ether and 0.5 g/l caustic soda, 8
The nonwoven fabrics were passed through one of the heated dimethylformamide baths at 0°C for 5 minutes, squeezed with a mangle, thoroughly rinsed with water, and heated and dried at 110°C to form treated nonwoven fabrics of 4 dishes [simple hot water treatment 1]. dish (Comparative Example 1), two types of chemical treatment (Inventive Example 1.2).

One type of organic solvent treatment (Example 8 of the present invention)] was obtained. As a result of this treatment, all four types of nonwoven fabrics shrunk by 32% in area.

Using each of these treated nonwoven fabrics, leather-like sheet-like products were created in the following manner. Polymerization degree 5005 Saponification degree 8
The treated nonwoven fabric was immersed in a 10% aqueous solution of 8 mol% partially saponified polyvinyl alcohol, squeezed, and dried on a net dryer at 110°C. The adhesion rate of polyvinyl alcohol to the nonwoven fabric by this treatment was 20%.

Next, a polyurethane elastomer consisting of polybutylene adiper 1-14.4' diphenylmethane diisocyanate and ethylene glycol [trade name: Chrisbon 8616, manufactured by Dainippon Ink & Chemicals, 100% elongation modulus 290 kg/am'') A 17% dimethylformamide solution was prepared.

Then, a polyvinyl alcohol-treated nonwoven fabric was pressed using a flat plate press machine with a hot plate temperature of 120°C, and the thickness was reduced to 1.
．． The nonwoven fabric was impregnated with a regulated polyurethane elastomer solution of 4rrtm, and after scraping off the excess polyurethane elastomer solution on the surface of the nonwoven fabric with a doctor knife, it was wet-coagulated in a 10% dimethylformamide aqueous solution at 40°C, and then thoroughly washed with water at 60°C. After removing polyvinyl alcohol and dimethylformamide, the product was dried by heating at 120°C.

The four types of leather-like sheets obtained in this way all had a thickness of 1.4 mm, a date of 490 g/m, and an apparent density of 0.85 g/Cm3, and were made of fibers and polyurethane elastomer. The ratio (hereinafter referred to as F/R ratio) was similar to 60/40. This 4th class leather 1st
Table * Vertical x horizontal (same for each example below) As can be seen from Table 1, sheet-like products obtained by the method of the present invention (inventive examples 1, 2 and 8) treated with chemicals or organic solvents.
) showed a significantly lower Gurley bending resistance than the conventionally processed sheet material (Comparative Example 1) that was not subjected to this treatment, and in actual sensory tests, it was found to be extremely flexible and fulfilling. It exhibited an excellent leather-like feel.

Comparative Example 2 In Example 1, the nonwoven fabric was passed through a hot water bath at 80°C containing 5 g/l of polyoxyethylene (8 moles of ethylene) nonylphenyl ether, and after squeezing with a mangle, it was immediately dried without washing with water. The sheet material obtained in the same manner as in Inventive Example 1 had the same thickness, basis weight, density, etc. as the sheet material obtained in Inventive Example 1, but its Gurley stiffness The softness was 1800 mg and the flexibility was poor.

Comparative Example 3 A sheet-like article (thickness: 1.4 mm) obtained in the same manner as in Comparative Example 1 (conventional method) except that the amount of polyvinyl alcohol adhered to the nonwoven fabric was increased to 50%.
, area weight 472 g/m, apparent density 0.34 g/cm
8, F/R=62/88) has a Gurley stiffness of 12
It was 70 mg and had poor flexibility.

Example 2 Fineness: 1.5 d, fiber length: 51 mm, number of crimps: 1
Using the same method as in Example 1 using 2 threads/inch 6-nylon short fibers, the thickness was 2.0rnrr1 and the date was 260 g/
A nonwoven fabric of fn2 was created.

The nonwoven fabric was passed through either an 80°C hot water bath or an 80"C hot water bath containing 5 g/l of sodium alkylbenzenesulfonate (trade name, Neoperex, manufactured by Kao Atlas ■) for 5 minutes. After squeezing and squeezing the mangle liquid, it was thoroughly washed with water.Then, in the same manner as in Example 1, it was dried, applied with polyvinyl alcohol (fixed amount: 15%), heated, and impregnated with polyurethane elastomer to obtain two types of sheet-like products. Table 2 shows the physical properties of these two types of sheet materials.

Table 2 As shown in Table 2, the sheet-like material obtained by treating the nonwoven fabric with an aqueous solution of sodium alkylbenzenesulfonate (Inventive Example 4) is different from the sheet-like material that is not treated with the chemical (Comparative Example 4). Compared to the above, the Gurley bending resistance was significantly lower, it was softer, and it had a very preferable leather-like feel.

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Claims (1)

[Claims] (1) A base fabric mainly composed of synthetic fibers is treated with a chemical or an organic solvent, and after removing the treatment agent, a water-soluble polymer substance is fixed thereon, and then impregnated with a solution of a polyurethane elastomer in a water-miscible organic solvent, This is wet coagulated in an aqueous medium,
A method for producing a flexible leather-like sheet material characterized by washing with water and drying.