KR950008478B1 - Thermoplastic resin composition having reduced cast erosion and excellent weld strengtn - Google Patents

Abstract

An acrylonitrile-butadiene-styrene/ethylene-polyvinyl chloride polymer (degree of polymerization = 430-550) composition having a weight ratio of ABS : ethylene -PVC resin of 30-60:40-70 was prepared. Thus, ABS resin and ethylene-PVC resin and PVC resin were mixed in the ratio of 50:50, and added 5 parts of tin maleate as an organic tin compound thermal stabilizer, 1 part of ethylene bis-stearamide as an outer lubricant and 1 part of calcium stearate as an inner lubricant. A corrosion condition was tested after heating at 250 degree C for 4 hr.

Description

Thermoplastic composition with reduced mold corrosion and excellent weld strength

The present invention relates to a thermoplastic resin composition, and more particularly, to an acrylonitrile-butadiene-styrene graft copolymer (hereinafter referred to as "ABS") and a special vinyl chloride resin (hereinafter referred to as "ethylene-PVC"). To a constructed composition.

Conventional techniques for increasing the flame retardancy of ABS are broadly classified into a method of adding a flame retardant to ABS and a method of mixing PVC with ABS.

The addition of PVC to ABS has the advantage of low manufacturing atoms. There is a problem of severe mold corrosion due to chlorine gas generated from PVC during injection molding, and there is also a problem of chromium plating or other plating on the mold for use.

The method of adding a heat stabilizer to increase the flame retardancy has a problem in that the manufacturing cost is increased and the mold corrosion cannot be sufficiently prevented.

In addition, ABS and PVC mixed polymers are prone to thermal decomposition during molding process, so low temperatures are required for injection molding. Therefore, in the case of complex molded products or large molded articles with welds, they are difficult due to difficulty in molding. Drawbacks are weaknesses in the strength of the molding or weld sites.

In order to solve this problem, conventionally, lubricants are added to increase flowability and weld strength. However, in this case, a problem of deterioration in flame retardancy and physical properties due to excessive addition of lubricants occurs.

The present invention has been made to improve such a problem, and an object thereof is to provide a thermoplastic resin with reduced mold corrosion and improved weld strength.

The present inventors have studied to achieve the above, by using a mixture of ABS resin and ethylene-PVC, when adjusting the median pressure of the resin, and adjusting the PVC content, while maintaining the flame retardancy, the corrosion of the mold is reduced and the weld strength It has been found to improve.

The present invention is described in detail as follows.

Examples of ABS resins that can be used in the present invention include acrylonitrile-butadiene-styrene copolymers, acrylonitrile-butadiene-isoprene-styrene copolymers, acrylonitrile-butadiene- -Methylstyrene copolymer, acrylonitrile-butadiene-styrene -Methyl styrene copolymer, etc., and special PVC resins are ethylene-PVC copolymerized polymers polymerized with ethylene and vinyl chloride monomer.

General PVC is mainly used for injection molding as the mixed polymer of ABS and PVC. However, in order to remarkably mold corrosion, ethylene-PVC copolymer resin should be used, and the effect of increasing the weld strength cannot be expected by adjusting the degree of polymerization. The suitable degree of polymerization for increasing the weld strength is 400 ~ 700 level, and the more suitable range is 430 ~ 550 level, and below 430, the weld strength increases due to the increase of flow property, but the physical properties such as impact strength are deteriorated. Existing physical properties are improved but the weld strength is lowered. In addition, the proper adjustment of ABS and ethylene-PVC when using ethylene-PVC copolymer resin is important for reducing flame retardancy, weld strength and mold corrosion.

The amount of ethylene-PVC used is 20 to 70 parts by weight, more preferably 40 to 70 parts by weight, and when ethylene-PVC is 70 parts by weight or more, the weld strength is increased but mold corrosion resistance is increased. In this case, mold corrosion is reduced but flame retardancy and weld strength are decreased.

In the present invention, in addition to the organic maleate compound, which is an organic maleate compound and a metal-based stabilizer, a filler, an antistatic agent, a processing aid, an epoxy compound, a boron compound and the like may be added as necessary.

The method of adding an additive such as a heat stabilizer used in the present invention to ABS / ethylene-PVC is a conventional method. For example, ABS / ethylene-PVC and a heat stabilizer may be mixed using a blood shell mixer, or heat-sitting agents and the like may be mixed in advance using a Henschel mixer and then mixed with ABS / ethylene-PVC.

The practice of the present invention is as follows.

Example 1

Ethylene-PVC resin (TOSOH E-600, E-550, E-430) and general PVC resin (Hanyoung Chemical, P-1000, 800, 700, 423) are ABS resins (Cheil Industries, Ltd., HF-0660 I) ) In a 50:50 ratio to compare the mold corrosion conditions. At this time, 5 parts by weight of tin malate (Sankyo Co., Ltd., STANN BMCN), an organic stone compound thermal stabilizer, was added, and an external lubricant was used (Ethylene bis-Stearamide) and an internal lubricant. 1 part by weight of calcium stearate was added.

The mold corrosion test method is to put a cube mold (material kp4) of 1.5 cm in length into a 100 ml beaker, 30 g each of ABS / PVC, and ABS / ethylene-PVC resin, and seal it and heat it at 250 ° C for 4 hours in a dry oven. After the mold corrosion state was confirmed. The degree of discoloration of the mold was visually determined, and the evaluation of the mold was unchanged: 1, yellow brown section: 2, brown: 3, dark brown: 4, and black: 5.

Table 1

As can be seen in Example 1, the use of ethylene-PVC resulted in less mold corrosion than the use of ordinary PVC.

Example 2

Ethylene-PVC resin (TOSOH Co., Ltd. E-430, E-550, E-600) or general PVC resin (Hanyang Chemical Co., Ltd. P-1000, P-800, P-700, P-432) Mold corrosion was evaluated by mixing the resin (Cheil Industries, HF-0660I) in a 50:50 ratio. Additives and test methods were the same as in Example 1, and the weld strength test was performed by injecting two gates to the flame retardant (1/8 ") specimens to produce a specimen with a certain length at the welded portion and the same as the IZOD test method. The comparison was made.

TABLE 2

As a result of the test of Table 2, ethylene-PVC has the same effect on the mold corrosion state even when the degree of polymerization (expressed as grade) is increased, and the weld strength increases as the degree of polymerization is lower.

The suitable polymerization degree is 430-550 by this, and ethylene-PVC is suitable.

Example 3

The ethylene-PVC resins (TOSOH, E-430, E-52) and ABS resins (Cheil Industries, HF-0660I) were changed in content (20 to 70 parts by weight) to compare weld strength, mold corrosion, and flame resistance.

Mold corrosion and weld strength tests were carried out in the same manner as in Examples 1 and 2, and the flame retardancy was carried out according to the UL 94 Test method. The results are shown in Table 3 below.

TABLE 3

As can be seen from Table 3, the use ratio of ABS and ethylene-PVC in which the weld strength and the flame retardancy are maintained at the same time and the mold discoloration is reduced is 30 to 60: 40 to 70 parts by weight.

Claims (2)

ABS: The weight ratio of ethylene-PVC resin is 30-60: 40-70, The ABS / ethylene-PVC mixed polymer composition characterized by the above-mentioned. The ABS / ethylene-PVC blended polymer composition according to claim 1, wherein the degree of ethylene-PVC polymerization is 430 to 550.