JPS62277454A - Vinyl chloride resin composition for injection molding - Google Patents

Abstract

PURPOSE:The titled composition suitable as the sole of a boot by injection molding, etc., causing neither bad injection nor dye bleeding, having improved wear resistance, obtained by blending a specific ethylene-vinyl chloride copolymer resin with specific amounts of a plasticizer, a stabilizer, etc. CONSTITUTION:100pts.wt. ethylene-vinyl chloride copolymer resin having 0.5-5wt%, preferably 1-3wt% ethylene content and 1,800-3,000, preferably 2,200-2,800 average polymerization degree is blended with (A) 65-95pts.wt., preferably 75-85pts.wt. plasticizer (e.g. dibutyl phthalate, etc.), (B) 1-3pts.wt., preferably 1-2pts.wt. stabilizer (e.g. dibutyltin laurate, etc.) and (C) 1-3pts.wt., preferably 1.5-2pts.wt. colorant (e.g. phthalocyanine green, etc.).

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a vinyl chloride resin composition for injection molding,
More specifically, the present invention relates to a vinyl chloride resin composition for injection molding, which is suitable as an injection molding material for the soles of injection molded boots.

[Prior Art] Conventionally, as a vinyl chloride resin composition for injection molding, a composition prepared by blending a plasticizer and the like with vinyl chloride resin (so-called straight PVC), which is a vinyl chloride homopolymer, has been widely used.

Recently, using this resin composition, as shown in FIG.
Two-color injection molded boots A are being developed, in which the shoe sole 3 and the shoe sole 3 are integrally molded. When injection molding the boots A, for example, as shown in FIG. After molding the sole 3 by injecting the molding material), the dummy mold is removed, or the sole 3, which has been previously molded with a vinyl chloride resin composition for sole molding, is placed in the bottom mold 4. 112, and then combine the main body last 5 covered with the lining cloth 2 and the side mold 6 to form a main body molding cavity 7, and into this molding cavity 7, from the injection hole 8 on the sole side, a mold different from the sole 3 is formed. A method for injecting vinyl chloride resin (body molding material) for body molding is being developed.

Here, the vinyl chloride resin composition for shoe sole molding, which is a shoe sole molding material, has an average degree of polymerization of, for example, 1.050 to 1.
, 450 vinyl chloride resin (straight PVC) 100
Based on parts by weight, 65 to 100 parts by weight of plasticizer, 1 to 100 parts by weight of stabilizer
The one containing 2.5 parts by weight and 1 to 3 parts by weight of colorant is
In addition, the vinyl chloride resin composition for molding the main body, which is the main body molding material, has an average degree of polymerization of 1,050 to 1,45, for example.
A mixture of 105 to 115 parts by weight of a plasticizer, 1 to 3 parts by weight of a stabilizer, and 1 to 3 parts by weight of a colorant is used with respect to 100 parts by weight of a vinyl chloride resin (straight PVC) having a composition of 0.0 to 100 parts by weight.

[Problem that the invention seeks to solve]

However, a shoe sole with a thickness of 2 to 3 cm is injection molded using the above-mentioned vinyl chloride resin composition for shoe sole molding as a molding material, or the sole is molded in advance and then used to form the boot body. When injection molding is used to produce two-color injection molded boots, the soles may be thin.
Due to the temperature and pressure of the body molding material that will be injection molded later, the sole peripheral part (edge part) 3 inscribed in the boot body of the sole
It has been found that a phenomenon such as a (see Fig. 1) is mixed into the boot body as a color bleed, making it impossible to produce beautiful two-color injection molded boots.

This phenomenon often occurs at the boundary between the sole and the boot body, and the more transparent the hue of the boot body, the more noticeable it is.
There is a risk that the boots will have no commercial value.

Possible ways to solve these problems include increasing the average degree of polymerization of the straight PVC used as the sole molding material, or reducing the amount of plasticizer while keeping the average degree of polymerization the same. It was found that both of them had problems, such as the fact that they were thin, which hindered their workability, and that the molding material could not be completely injected into the mold.

The present invention was developed in view of these technical issues, and it is easy to injection mold without causing injection defects, does not cause color bleeding when molding two-color injection molded boots, and is easy to use after molding. The purpose of the present invention is to provide a vinyl chloride resin composition for injection molding which has excellent physical properties such as abrasion resistance and bending resistance.

[Means for solving problems]

That is, in the present invention, the average degree of polymerization is 1,800 to 3,0.
Vinyl chloride for injection molding, characterized in that it contains 65 to 95 parts by weight of a plasticizer, 1 to 3 parts by weight of a stabilizer, and 1 to 3 parts by weight of a colorant, based on 100 parts by weight of the ethylene-vinyl chloride copolymer resin of No. 00. The present invention provides a system resin composition.

The ethylene-vinyl chloride copolymer resin used in the present invention is a copolymer in which vinyl chloride is the main repeating structural unit and ethylene is copolymerized with this, and the ethylene content (ethylene content) as a copolymer component is The content of the recycled structural unit (returning structural unit) is usually 0.5 to 5% by weight, preferably 1 to 3% by weight, and 0.5% by weight causes injection molding defects and color bleeding during injection molding, while 5% by weight If it exceeds 20%, the proportion of ethylene, which is a copolymerization component, will increase, making it difficult to produce the copolymer resin, and the melt viscosity during injection molding may become too low, or sink marks may occur on the molded product, or thermal decomposition may occur during molding. This is not desirable as it may cause

The average degree of polymerization of this ethylene-vinyl chloride copolymer resin is
1,800-3,000, preferably 2.200-2,
If it is less than 1,800, the degree of polymerization is too low and injection moldability is excellent, but color bleeding occurs, and physical properties such as abrasion resistance, compression molding distortion, and shape retention at high temperatures are poor after molding. On the other hand, if it exceeds 3.000, the degree of polymerization is too high, resulting in poor injection moldability such as poor injection, and injection molding distortion becomes large, causing molded products (for example, shoe soles) to shrink even after molding. .

The vinyl chloride resin composition for injection molding of the present invention is a composition in which the ethylene-vinyl chloride copolymer resin contains a plasticizer, a stabilizer, and a colorant.

Examples of plasticizers include phthalic acid esters such as dibutyl phthalate, dioctyl phthalate, and butylbenzyl phthalate; aliphatic polybasic acid esters such as dioctyl adipate, dioctyl azelate, and dioctyl sebacate; and phosphoric acid esters such as tricresyl phosphate. Further examples include citric acid esters, epoxy plasticizers, polyester plasticizers, urethane plasticizers, and preferably phthalic acid esters. The amount of plasticizer used is 65 to 95 parts by weight, preferably 75 to 85 parts by weight, per 100 parts by weight of the ethylene-vinyl chloride copolymer resin. If it is less than 65 parts by weight, phenomena such as poor injection may occur. On the other hand, if it exceeds 95 parts by weight, color bleeding may occur.

Examples of the stabilizer include tin-based stabilizers such as dibutyltin laurate, and metal soaps such as zinc stearate and calcium stearate.

The amount of this stabilizer used is 1 to 3 parts by weight, preferably 1 to 3 parts by weight, per 100 parts by weight of the ethylene-vinyl chloride copolymer resin.
2 parts by weight, and if it is less than 1 part by weight, thermal stability is poor;
On the other hand, even if more than 3 parts by weight is used, the effect of using the stabilizer will not be proportionally the same (and it is uneconomical) because thermal decomposition may occur during molding.

Furthermore, examples of the coloring agent include phthalocyanine green, chrome yellow, titanium oxide, and colored carbon blank, which are appropriately selected depending on the injection molded product to be obtained, such as the sole of a shoe. The amount of this colorant used is 10 (lf
It is 1 to 3 parts by weight, preferably 1.5 to 2 parts by weight, based on part i. If it is less than 1 part by weight, the coloring effect of the injection molded product obtained is poor, and the colorant tends to be unevenly dispersed ( ,
On the other hand, if the amount exceeds 3 parts by weight, the coloring effect will not increase proportionally and it will be uneconomical.

The vinyl chloride resin composition of the present invention can be used as it is, but if necessary, other thermoplastic resins, rubbers, fillers, lubricants, etc. may be added to it.

Other thermoplastic resins include, for example, straight PVC,
ABS resin, chlorinated polyethylene, ethylene-vinyl acetate copolymer, urethane, acrylic resin, etc. are used, and as the rubber, acrylonitrile-butadiene rubber is used, and the content of these is 100% of the ethylene-vinyl chloride resin of the present invention. It is usually used in an amount of 30 parts by weight or less.

Further, as fillers, for example, calcium carbonate, talc, titanium oxide, aluminum hydroxide, magnesium hydroxide, clay, magnesium carbonate, etc. are used in appropriate amounts as required.

Further, as the lubricant, for example, a lubricant commonly used for vinyl chloride resins such as higher fatty acid ester or low molecular weight polyethylene is used.

The vinyl chloride resin composition of the present invention is mixed and kneaded in the same manner as conventional vinyl chloride resin compositions, and used as an injection molding material.

That is, ethylene-vinyl chloride resin, plasticizer, stabilizer,
Colorants, and if necessary other thermoplastics, rubbers,
The mixture is mixed with fillers, lubricants, etc., kneaded using a Banbury mixer, mixing rolls, extruder, etc., and then granulated if necessary to be used as an injection molding material.

The vinyl chloride resin composition for injection molding of the present invention can be used in all fields for injection molding, such as basso, kin, tubes, hoses, leather, electric wire coatings, bellows-shaped molded products, automobile bumpers, bicycle handle grips, etc. However, it is particularly effective in manufacturing the soles of two-color injection molded boots and general shoes.

In addition, when the injection molding material of the present invention is used as a sole molding material for two-color injection molded boots, the above-mentioned conventional vinyl chloride resin composition for body molding is used as the molding material for the boots body. Ru.

〔Example〕

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Examples 1 to 2 and Comparative Examples 1 to 6 Two-color injection molded boots having the structure shown in FIG. 1 were manufactured using the apparatus shown in FIG. 2. At this time, the vinyl chloride resin composition that is the molding material for the boots body 1 has the following formulation.
The molding materials for the sole 3 were those shown in Table 1.

The molding temperature and injection pressure were 198°C for the sole 3;
60kg/cffl-Q, boots body 1 is 196℃, 40
kg/ctA-G.

The results are shown in Table 1.

In Table 1, injection failure refers to cases where the sole molding material gets stuck at the toe during sole molding, resulting in a filling failure. Represented by ×. In addition, colored lacquer is a phenomenon in which the molding materials of the boot body 1 and the sole 3 are melted and mixed together at the edge portion 3a of the sole.
, those that occur are indicated by ×.

Vinyl chloride resin composition (boots body) Compounding Straight PVC (average degree of polymerization 1,300) i 100 parts by weight Plasticizer (dioctyl phthalate, DOP); 100 parts by weight Stabilizer (dibutyltin laurate); 2 parts by weight Coloring Agent (
Anatase type titanium oxide); 2 parts by weight *2) Dibutyltin laurate *3) Anatase type titanium oxide As is clear from Table 1, the resin composition of the present invention has poor flow characteristics despite its high average degree of polymerization. Since the properties of the conventional straight PVC are significantly improved, no injection defects or color bleeding occur, making them excellent injection molding materials.
In the case of using , color bleeding occurred (Comparative Examples 1 to 2), and when the amount of plasticizer was reduced to prevent this, injection defects occurred even more (Comparative Example 3), the average degree of polymerization was increased somewhat. In addition, color flow was not improved, and injection defects occurred (Comparative Example 4).If the average degree of polymerization was further increased, color flow was improved, but injection defects became worse (Comparative Example 5). Also,
Even when an ethylene-vinyl chloride copolymer resin is used, color flow is not improved if the average degree of polymerization is low (Comparative Example 6).

Comparative Example 7 Two-color injection molded boots were manufactured in the same manner as in Example 2 except that an ethylene-vinyl chloride copolymer resin with an average degree of polymerization of 3,200 was used. Although color bleeding did not occur, injection molding A defect has occurred.

〔Effect of the invention〕

As described above, according to the present invention, injection molding is easy without injection defects, color bleeding does not occur when molding two-color injection molded boots, etc., and furthermore, after molding, it has good wear resistance and bending resistance. It is possible to provide a vinyl chloride resin composition for injection molding that has excellent physical properties such as.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of two-color injection molded boots, and FIG. 2 is a longitudinal sectional view of the injection molded rain boots manufacturing apparatus of FIG. 1.

Claims (2)

[Claims] (1) 6 parts by weight of plasticizer per 100 parts by weight of ethylene-vinyl chloride copolymer resin having an average degree of polymerization of 1,800 to 3,000.
5-95 parts by weight, 1-3 parts by weight of stabilizer and 1-3 parts by weight of colorant.
3 parts by weight of a vinyl chloride resin composition for injection molding. (2) The vinyl chloride resin composition for injection molding according to claim 1, wherein the ethylene content contained in the ethylene-vinyl chloride copolymer resin is 0.5 to 5% by weight.