JPS606372B2 - Resin composition for fake leather - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition that is used to obtain hardened leather with excellent texture by a wet coagulation method, and more specifically, to an ethylene-vinyl acetate-vinyl chloride kraft copolymer. 10 parts by weight of EVA-VC copolymer A (hereinafter abbreviated as EVA-VC copolymer A), 20 parts by weight or less of one or more types of vinyl chloride resin or thermoplastic elastomer, and an inorganic compound-based thixotropic agent (chickentropant). )5 to 2 parts by weight of EV
One or more solvents that can dissolve A-VC copolymer A, vinyl chloride resin, and thermoplastic elastomer 400
A resin composition obtained by dissolving and dispersing in ~200 parts by weight, or a colloid obtained by further adding to the composition one or more nonsolvents that do not dissolve the polymer but are miscible with the solvent. The present invention relates to a resin composition.

Artificial leather is produced by impregnating or coating a solution or colloidal dispersion of polyurethane resin or nylon resin on a base material, and then immersing it in a non-solvent of the resin to coagulate and extract the solvent. The manufacturing method is well known as the wet coagulation method, which produces performance, texture, and texture close to that of natural leather.
A product with an appearance is obtained.

However, the material resin is relatively expensive, and it is manufactured through a complicated process that takes a long time, so there are economical problems, and it is limited to use as a luxury product and lacks versatility, as well as poor performance. Improvements in light resistance, flame retardance, chemical resistance, etc. are desired. On the other hand, hardened leather whose base material is coated with a polyvinyl chloride composition made by softening a vinyl chloride resin with a plasticizer is generally called PVC leather, and has excellent strength, weather resistance, soft flame resistance, and Although it is widely used due to its chemical properties and low cost, it is far inferior to polyurethane-based artificial leather in terms of feel and touch. Various attempts have been made to improve the feel, touch, appearance, etc. of PVC leather. For example, by foaming the coating layer and subjecting it to surface modification treatment, quite good results have been obtained. However, compared to the artificial leather mentioned above, it is still not sufficient. In view of these circumstances, the present inventors have endeavored to improve the feel of hardened leather using vinyl chloride resin, and have arrived at the present invention as a result of intensive studies aimed at obtaining an inexpensive imitation leather that is similar to artificial leather.

That is, it is based on EVA-VC copolymer A that has been internally plasticized with an ethylene-vinyl acetate copolymer, and if necessary, a vinyl chloride resin or a thermoplastic elastomer is used in combination to adjust the bulk. When producing vinyl chloride resin simulated leather by a wet coagulation method using a polymer mixture, it is common to use a commercially available shaker that imparts chicken tropancy to the polymer solution or pig substance liquid. Among the changing agents, by using an inorganic compound-based thixotropic agent, which is made by pulverizing the inorganic compound or by applying a slight surface treatment to the powder, the coagulation and solvent extraction steps can be significantly shortened, resulting in excellent texture and texture. touch and transparency,
It was discovered that a stiff leather with breathability could be obtained, and was produced.

Although it is not yet clear how inorganic compound-based thixotropic agents are involved in shortening the coagulation and solvent extraction processes or improving the texture of the coagulated leather, it is a fine powder with a significantly large specific surface area. This is considered to be a necessary condition. In addition, a method of manufacturing fake leather by a wet coagulation method using a solution of a European quality vinyl chloride resin composition consisting of a vinyl chloride resin, a plasticizer, a solvent, etc. has been proposed, for example, in Chiang Gongsho No. 47-34921. However, it is difficult to obtain simulated leather with excellent touch and feel, and it is thought that the large amount of low molecular weight plasticizers and the like are causing problems during the coagulation and solvent extraction processes.

In addition, in the production of polyurethane artificial leather, etc., there is a method of adding a surfactant etc. for the purpose of speeding up solvent extraction (for example, Japanese Patent Publication No. 38762/1983), or a method of adding a carboxylic acid, etc. for the purpose of forming a homogeneous porous layer. Various methods have been proposed, including the method of adding carboxylic acid esters, ethers, etc. as coagulation regulators (for example, Japanese Patent Publication No. 45-39635). Hardly any effect was observed in the production of solidified leather by the wet coagulation method of resin, and the present invention has developed a system based on internally plasticized vinyl chloride resin that contains almost no low molecular weight plasticizing components. It was found that only when hardened leather was produced by a wet coagulation method using a composition to which an inorganic compound-based thixotropic agent was added, productivity was dramatically increased and performance and texture were improved. The configuration of the present invention will be further explained below.

The EVA-VC copolymer A used in the present invention has a composition that can give flexibility comparable to that of commercially available PVC leather. A composition corresponding to a composition in which approximately 35 to 7 parts by weight of -gt is added is suitable. For this purpose, the content of ethylene-vinyl acetate copolymer in EVA-VC copolymer A is in the range of 40 to 6% by weight, and the content of vinyl acetate in the ethylene-vinyl acetate copolymer is in the range of 35 to 6% by weight. A range of 75% by weight is suitable. In addition to using such EVA-VC copolymer A alone, compatibility with vinyl chloride resin other than EVA-VC copolymer A or EVA-VC copolymer A is used for the purpose of changing flexibility. 2 parts by weight of EVA-VC copolymer AIOO of one or more thermoplastic elastomers having
It is possible to use an amount of up to 1 part by weight. EVA
-The vinyl chloride resin used in combination with VC copolymer A is a vinyl chloride copolymer containing 61% by weight or more of vinyl chloride, and for example, the content of ethylene-vinyl acetate copolymer is less than 40%. Ethylene-vinyl acetate-
Examples include vinyl chloride copolymer B, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic acid alkyl ester, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, and the like. Examples of thermoplastic elastomers include, for example, ethylene-vinyl acetate copolymers with an ethylene content of 35 to 6% by weight, or ternary copolymers made of ethylene, vinyl acetate, and other copolymerizable monomers. a butadiene-acrylonitrile copolymer with an acrylonitrile content of 30 to 5% by weight, or an ester of a C4-8 monohydric alkyl alcohol and acrylic acid or methacrylic acid of 7% by weight or more. Examples include acrylic acid ester or methacrylic acid ester polymerization copolymers. If the amount of vinyl chloride resin or thermoplastic elastomer used in combination with EVA-VC copolymer A exceeds 20 parts by weight, problems may occur with solubility in the solvent, or the amount required for coagulation and solvent extraction may occur. The time will be longer, and the performance and texture of the fine leather will be improved. The solvent used in the present invention includes N,N-
Dimethyl sulfoxide, N,N-diethyl sulfoxide, N,N-dimethylformamide, N,N-diethylformamide, tetrahydrofuran, dioxane, etc. are suitable, and may be used alone or in combination of two or more in any proportion. The amount used is in the range of 400 to 2000 parts by weight per 10 parts by weight of resin such as EVA-VC copolymer A, and if it is less than 400 parts by weight, the viscosity when made into a solution If the amount is too high, it may cause difficulties in the process of impregnating or coating the base material, or the wet coagulation process may not be carried out properly.Also, if the amount exceeds 2000 parts by weight, the viscosity of the system will decrease. Not only will it penetrate to the back side of the substrate and the coating thickness will become insufficient, but it will also impair economic efficiency in solvent recovery, etc.Also, if tetrahydrofuran is used as a solvent alone or in a mixture containing 5% by weight or more, When using EVA-VC copolymer A, the effect of dissolving EVA-VC copolymer A etc. is too strong, and the wet coagulation process may not be carried out well and the texture of the finished leather may be impaired. It is appropriate to use a non-solvent together.

Non-solvents used include water and C, -3 aliphatic alcohols. The amount of non-solvent to be added varies depending on the polymer used, the type and amount of solvent, so it cannot be stated unconditionally, but as the non-solvent is added, the viscosity of the polymer solution increases, and it further increases through the gelation state. Since it becomes a colloidal dispersion and eventually undergoes phase separation, it is appropriate to use an amount within a range that will reach the state just before it becomes a colloidal dispersion and the viscosity suddenly drops in this process. be.

In addition, as the inorganic thixotropic agent used in the present invention, commonly commercially available ones can be used, such as ultrafine powder silica, fine powder calcium carbonate, fine powder aluminum silicate, etc. Examples include those that have been treated with a small amount of a surface treatment agent.

Although some commercially available thixotropic agents are based on organic compounds, these types of thixotropic agents are not effective for the purpose of the present invention. A basic resin composition capable of wet coagulation is composed of the above-mentioned polymer, solvent, nonsolvent, and inorganic compound-based bridge change agent, but it is common knowledge in the industry that pigments, dyes,
Fillers and the like may be mixed in, and further stabilizers and a small amount of low molecular weight plasticizers may be added as necessary.

However, since these compounds often affect the texture and the like of the resulting hardened leather, it is necessary to carefully consider the amount of addition, etc. before using them. For example, low molecular weight plasticizers such as dioctyl phthalate used for the purpose of adjusting flexibility, various stabilizers and co-stabilizers that have the effect of improving the thermal stability of vinyl chloride resins, especially liquid ones, etc. As mentioned above, since it has an adverse effect on the wet coagulation process and impairs the texture, it should be used in as small a quantity as possible, preferably no more than 5 parts by weight based on the weight of the polymer 10. The production of simulated leather using the composition of the present invention is carried out by a wet coagulation method which is commonly used in the production of polyurethane artificial leather.

That is, woven fabric, non-woven fabric, knitted fabric, etc. are used as the base material, and a polymer solution or colloidal dispersion is applied to the surface, or in some cases, it is impregnated by penetrating into the interior of the base material using a coater or the like.
Alternatively, the base material is immersed in a polymer solution, further squeezed if necessary, and then immersed in a non-solvent tank for wet coagulation, followed by solvent extraction and a drying process to form solidified leather. obtain. In addition, the crude product or original fabric obtained through these steps is coated again, green coagulation, and solvent extracted to form a top layer, or treated with a commonly used surface finishing agent to improve wear resistance. It is also possible to add shine or shine. The vinyl chloride resin simulated leather obtained in this way has a good touch texture and is inexpensive, so it can be used for clothing,
It is suitable for a wide range of applications such as furniture, bags, footwear, gloves, etc. The present invention will be explained below with reference to Examples.

Example 1 EVA-
9 parts by weight of VC copolymer (trade name: Sumigraft GE, manufactured by Sumitomo Chemical Co., Ltd.) and ultrafine powder silica (trade name: AEROS)
Add 2 parts by weight of IL (manufactured by Nippon Aerosil Co., Ltd.) to Hina Yoshita 6.
A viscous steel solution was prepared by melting while heating to 0 to 8 pm.

Next, apply this to a cotton cloth to a thickness of about 1.5 cm and heat at 60 to 70℃.
The powder was soaked one by one in hot water to form a porous coagulated layer, and then dried at 8000 for 30 minutes.

A soft leather with a good texture and no sticky surface was obtained. Example 2 Adding EVA to 100 parts by weight of N,N-dimethylformamide
14 parts by weight of VC copolymer (trade name: Sumigraft OE, GF equivalence mixture, manufactured by Sumitomo Chemical Co., Ltd.) and 3 parts by weight of ethylene-vinyl acetate copolymer (trade name: Evatate R 5011, manufactured by Sumitomo Chemical Co., Ltd.) 1 part and 2 parts by weight of ultrafine powder silica were added and dissolved while heating at 60 to 80 DEG C., and then cooled to about 4000 t to prepare a clayey rice solution.

Next, apply this to a cotton cloth to a thickness of about 1.5 skin and apply it to a thickness of 60 to 700.
After soaking in warm water of 0.0 for 10 minutes to form a porous coagulated layer, it was dried for 3 times at 80q0 to obtain a soft, non-sticky fake leather with a good texture. Example 3 EVA-VC copolymer (trade name: Sumigraft G) was added to 8 parts by weight of N,N-dimethylformamide and 2 parts by weight of tetrahydrofuran.
FL, manufactured by Sumitomo Chemical Co., Ltd.), 10 parts by weight of ethylene-vinyl acetate copolymer (trade name: Evatate R 5011, manufactured by Sumitomo Chemical Co., Ltd.), and surface-treated ultrafine calcium carbonate (White Gloss Leather CCR, manufactured by Shiraishi Calcium Co., Ltd.). ) was added and dissolved while heating to a temperature of 50 to 6,000 ℃ under condensation, and then about 20
00 to prepare a viscous steel solution.

Next, this was applied to a cotton cloth to a thickness of about 1.5 yen, soaked in 2000 ml of water for 2 minutes to wet coagulate, and then soaked in 35 to 4000 ml of hot water for 5 minutes and 60 to 7000 ml of warm water for 5 minutes. After forming a porous solidified layer, it was dried at 80q0 for 30 minutes. A soft leather with a good texture and no sticky surface was obtained. Comparative Example 1 A viscous steel solution was prepared from Example 3 except for ultrafine powdered silica, and wet coagulated in the same process to obtain solidified leather.

It was hard and had a sticky surface, making it impossible to obtain stiff leather with a good texture. In order to obtain stiffened leather with a good texture similar to that in Example 3, after applying a sticky steel solution to a cotton cloth,
It was necessary to immerse the device in hot water at a temperature of 60 to 7,000 for 30 minutes or more for 5 minutes. Example 4 2 of EVA-VC copolymer (trade name: Sumigraft GFL, manufactured by Sumitomo Chemical Co., Ltd.) was added to 100 parts by weight of tetrahydrofuran.
After adding and dissolving 2 parts by weight of ultrafine powder silica at room temperature, a 7:3 mixture of tetrahydrofuran and water was added dropwise under condensation until the solution became cloudy, and a colloidal form was obtained. A dispersion liquid was prepared.

Next, this was applied to a cotton cloth to a thickness of about 1.5 cm, soaked in 20 oo of water for 2 minutes to cause green coagulation, and then soaked in warm water at 40 to 50°C for 10 minutes to form a porous coagulated layer. After
It was dried at 8000 for 30 minutes.

A soft, non-sticky fake leather with a good texture was obtained. Comparative Example 2 The tetrahydrofuran/EVA-VC solution of Example 4 was directly applied to a cotton cloth and wet-coagulated in the same process to obtain solidified leather.

The surface was sticky and hard, and it was not possible to obtain stiff leather with a good texture.

Claims (1)

[Claims] 1. The content of ethylene-vinyl acetate copolymer is 40 to 60
100 parts by weight of ethylene-vinyl acetate monochloride kraft copolymer, 61 parts by weight of vinyl chloride units
0 to 20 parts by weight of one or more of the above vinyl chloride copolymers or thermoplastic elastomers and 5 to 20 parts by weight of an inorganic compound thixotropic agent are dissolved and dispersed in one or more solvents. A resin composition for hardening leather produced by a wet coagulation method with excellent texture. 2. The resin composition according to claim 1, which is made into a colloidal dispersion by adding an appropriate amount of non-solvent. 3. Claims 1 or 2 each containing 0 to 5 parts by weight of pigments, stabilizers, plasticizers, fillers, etc. as necessary.
The resin composition described in .