KR20010018020A - Environmental stress crack resistant abs resin compositions - Google Patents

Abstract

PURPOSE: Provided is an ABS resin composition which has improved chemical resistance with being maintained physical properties equally. The composition can be used in internal parts of a refrigerator. CONSTITUTION: The ABS resin composition comprises 98-70 parts by weight of acrylonitrile-butadiene-styrene(ABS) as basic resin; 2-30 parts by weight of polyolefin compound; 10-30 parts by weight of a compound grafted with acrylonitrile-styrene(SAN) and polyolefin as a compatibilizer based on 100 parts by weight of polyolefin compound. The compatibilizer contains acrylonitrile-styrene resin(LDPE-g-SAN) grafted to low density polyethylene, acrylonitrile-styrene resin(PP-g-SAN) grafted to polypropylene, acrylonitrile-styrene resin(EVA-g-SAN) grafted to ethylene vinyl acetate, or a mixed resin thereof.

Description

ABS resin composition excellent in chemical resistance {ENVIRONMENTAL STRESS CRACK RESISTANT ABS RESIN COMPOSITIONS}

The present invention relates to an ABS resin composition having excellent chemical resistance, and more particularly, to an acrylonitrile-butadiene-styrene resin, a polyolefin compound, and a compatibilizer in which acrylonitrile-styrene is grafted to a polyolefin. It relates to an ABS resin composition excellent in chemical resistance.

In general, the outer wall surface of the electric refrigerator is composed of a steel plate, the inner wall surface and the inner wall surface of the door is made of an inner body of the resin made by vacuum forming a sheet made of a thin plate through a sheet extruder. In addition, a part of the connection portion between the outer steel plate and the inner resin molding is assembled with a lid and a sheet made by injection molding the resin. The urethane liquid is injected between the inner and outer wall surfaces of the assembled refrigerator, and then foamed and solidified at an appropriate temperature to form a heat insulating layer of the refrigerator. In the urethane liquid which is a raw material of the foamed polyurethane foam insulation layer, a foaming agent such as freon is used to form a foam, and these foaming agents are used in areas where stress is concentrated by contact with a portion made of a resin during or after manufacturing a refrigerator. It causes chemical erosion and causes cracks in the upper body or molded resin products. Therefore, it is essential that the resin used in the vacuum molded upper body or the injection molded part of the refrigerator has resistance to such a blowing agent.

Acrylonitrile-butadiene-styrene resins (ABS resins) and rubber-modified polystyrene resins (HIPS resins) are mainly used for the upper body and parts of refrigerators, and ongoing research is being conducted to improve the resistance to the above blowing agents. have. In addition, as the problem of the impact on the global environment due to the ozone layer destruction of the freon compound used as a blowing agent has been recently raised, the use of alternative freon compounds has increased, and some of these alternative freon compounds have a much stronger chemical resistance to resins used in refrigerators. As a result of the erosion, it is necessary to develop a new resin having improved chemical resistance.

As an example of a technique for improving the resistance to a conventional blowing agent, a method using 800,000 or more high molecular weight styrene-acrylonitrile (SAN) resins, such as European Patent No. 19,728, 2 having different graft ratios from Japanese Patent Publication No. 2-175745 A method of using a rubber of a species has been proposed, and as a method for improving the resistance to the alternative Freon HCFC-141b, the content of vinyl cyanide is increased as in Japanese Patent Laid-Open Nos. 2-284906 and 4-170460. High nitrile acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene-acrylate resin (ASA), high nitrile styrene-acrylic as in Japanese Laid-Open Patent Publication No. 6-262713 The ternary resin composition of ronitrile resin (High-nitrile SAN) etc. can be proposed.

However, the method of European Patent No. 19,728 has extremely poor workability, and Japanese Patent Laid-Open No. 2-175745 has a complicated manufacturing process, and has high vinyl cyanide content in Japanese Patent Laid-Open No. 2-284906 and Japanese Patent Laid-Open No. 4-170460. Resin has a problem of deterioration in product value due to deterioration of workability or intensification of discoloration during processing. When acrylic rubber is used in the direct compounding process as in Japanese Patent Laid-Open No. 6-262713, the physical property such as impact strength is severely deteriorated. Problems occur in use. On the other hand, even when acrylonitrile-styrene-acrylate (g-ASA) resin is used as in Japanese Patent Application Laid-open No. Hei 4-170460, the impact strength decreases because the acrylic rubber component has a higher glass transition temperature than the diene rubber component. There was.

The present invention is to solve such a problem, to provide a resin composition that can be applied to the upper body and injection molded parts to be applied to the refrigerator is particularly excellent in chemical resistance while maintaining good impact resistance, color stability.

This object of the present invention can be achieved by providing a resin composition composed of a polyolefin compound having an appropriate molecular weight as an ABS resin and a compound obtained by grafting SAN to a polyolefin as a compatibilizer thereof.

That is, the present invention is 98 to 70 parts by weight of acrylonitrile-butadiene-styrene (ABS) resin; and 2 to 30 parts by weight of a polyolefin compound; And 10 to 30 parts by weight of a compound obtained by grafting acrylonitrile-styrene (SAN) to polyolefin as a compatibilizer with respect to 100 parts by weight of the polyolefin compound.

Hereinafter, the present invention will be described in detail.

The acrylonitrile-butadiene-styrene (ABS) resin used as the base resin in the present invention accounts for 98 to 70 parts by weight of the resin composition, which depends on the content of the polyolefin compound described later. The acrylonitrile content in the ABS resin of the present invention is not limited, but the acrylonitrile content may be adjusted according to the type of blowing agent corresponding thereto. When a blowing agent having a high permeability such as HFC-245fa or HCFC-141b is used, It is desirable to increase the acrylonitrile content in the ABS resin to 25 to 35% by weight. Increasing the acrylonitrile component in the resin increases the chemical resistance of the resin, but has a disadvantage in that the workability is lowered and the phenomenon that the color of the resin turns yellow during processing.

The polyolefin compound used in the present invention is not only waxes having a number average molecular weight in the range of 500 to 30,000, but also up to 30,000 or more polymers, but if the molecular weight is less than 500, there is a problem in that an appropriate level of chemical resistance cannot be secured. Not desirable The polyolefin compound, which is a characteristic component of the resin composition of the present invention, increases the content of acrylonitrile in order to have a conventional ABS resin having chemical resistance, thereby overcoming the disadvantage of deterioration in processability and whiteness, and thus low acrylonitrile content. It plays a role of having high chemical resistance in. As the waxes usable in the present invention, if the molecular weight is 500 or more, conventional polyolefin waxes can be used without limitation. For example, polyethylene wax, polypropylene wax, ethylene propylene copolymer wax, and the like are based on these. Oxidized polyethylene waxes, oxidized polypropylene waxes, oxidized ethylene propylene copolymer waxes, etc., in which acid groups are bonded, and polystyrene, polyα-methylstyrene, and polyt-butylstyrene are copolymerized with these polyolefins. As described, polyolefin waxes modified with aromatic monomers may also be used. Polymers usable in the present invention are based on polyethylene (low density, ultra low density, high density), polypropylene, ethylene propylene copolymer, and modified with oxidized polyethylene, oxidized polypropylene, oxidized ethylene propylene copolymer, or aromatic monomer. All polyolefins. The preferred content of the polyolefin compound is 2 to 30 parts by weight, the use of less than 2 parts by weight of the effect is insignificant, when it exceeds 30 parts by weight is not preferable because the surface gloss of the plate-like sheet is reduced. More preferably, it is good to use 5-15 weight part.

Compatibilizers that make a great feature in the present invention include a resin in which acrylonitrile-styrene resin is grafted to low density polyethylene (LDPE-g-SAN), and a resin in which acrylonitrile-styrene resin is grafted to polypropylene (PP-g). -SAN), and a resin obtained by grafting acrylonitrile-styrene resin to ethylene vinyl acetate (EVA-g-SAN) can be used. The content of the grafted acrylonitrile-styrene resin in the compatibilizer is 5 70 weight%, Preferably 10-40 weight% is suitable. The compatibilizer of the present invention serves to promote the mixing of the ABS resin and the polyolefin compound, and the content of the resin composition is suitably 10 to 30 parts by weight of the polyolefin compound used. When used less than 10 parts by weight of the resin composition during the long-term extrusion of the resin may occur due to the phase separation between the ABS resin and the polyolefin compound surface defects, when exceeding 30 parts by weight is not desirable in terms of price. The compatibilizer of the present invention can be used in various composition ratios according to the content and properties of the ABS base resin and the polyolefin compound to be used within the above range, the compatibility with the base resin is lowered as the molecular weight of the polyolefin compound increases It is desirable to increase the amount of the agent proportionately, and to lower the acrylonitrile content of the ABS base resin, it is desirable to increase the content of the compatibilizer (grafted with the SAN resin) to improve the chemical resistance.

The resin composition of the present invention, other than heat stabilizers, antioxidants, lubricants, lubricants, mold release agents, light and ultraviolet stabilizers, flame retardants, antistatic agents, colorants, fillers, impact modifiers, etc., as necessary without departing from the object of the present invention Additives can be added and other resins or rubber components can be mixed and used together.

In the following Examples, the present invention will be described in more detail, but the present invention is not limited to the following Examples.

Example 1

Acrylonitrile-butadiene-styrene (ABS) resin applicable to refrigerator inner phase (Cheil Industries Co., Ltd., polybutadiene content 13.5%, graft gum (acetone insoluble content) 22.3%, matrix component styrene-acrylic) LDPE obtained by grafting acrylonitrile-styrene resin to 9500 g of low density polyethylene (number average molecular weight 100,000) and 9500 g of acrylonitrile content in the matrix component of 210,000 and the content of acrylonitrile in the matrix component of 210,000 50 g of -g-SAN (LDPE molecular weight 100,000, LDPE / g-SAN = 70/30 weight ratio) is uniformly dispersed with other additives using a Henschel-type resin mixer and introduced into a twin screw extruder with a screw diameter of 45 mm at 220 ° C. The pellet was prepared at screw RPM 300. The resin pellets thus prepared were evaluated and analyzed by blowing agent CFC-11, and the results are shown in Table 1.

Example 2

Styrene-acrylonitrile resin, a matrix component, has a weight average molecular weight of 120,000 and an acrylic resin of 35% acrylonitrile in a matrix component of 9000 g of ABS resin, polypropylene having a number average molecular weight of 200,000 instead of LDPE, and LDPE- 100 g of PP-g-SAN in which acrylonitrile-styrene resin was grafted to polypropylene instead of g-SAN, and HCFC-141b instead of CFC-11 was used as the blowing agent compound, as in Example 1. The results are shown in Table 1.

Comparative Example 1

10000 g of ABS resin was used, except that low-density polyethylene and a compatibilizer were not used, and the results were shown in Table 1 below.

Comparative Example 2

10000 g of ABS resin was used, except that polypropylene and a compatibilizer were not used.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 ABS resin 9500 g 9000 g 10000 g 10000 g Acrylonitrile content in ABS resin 24% by weight 35 wt% 24% by weight 35 wt% Polyolefin 500 g polyethylene Polypropylene 1000g - - Compatibilizer LDPE-g-SAN50g PP-g-SAN100g - - Impact Strength (1/4 ") 26 32 27 34 Liquidity Index 6.2 6.5 6.0 5.8 blowing agent CFC-11 HCFC-141b CFC-11 HCFC-141b Critical strain (chemical resistance) ≥2.0 ≥2.0 ≤0.5 ≤0.8

〈Property Evaluation Method〉

-Mechanical property analysis: Using the 140 ton injection molding machine with the resin pellets prepared in the above Examples and Comparative Examples was prepared by injection molding specimens for physical property analysis in accordance with ASTM D1897-88. Impact strength was analyzed according to ASTM D256, and the fluidity index was analyzed under the condition of 220 ℃, 10㎏ according to ASTM D1238.

-Evaluation of chemical resistance: A 30 mm × 150 mm × 2 mm specimen was prepared by preheating at 220 ° C. for 2 minutes and compressing for 2 minutes using a compression molding machine. The prepared specimen was placed in a desiccator having a diameter of 30 mm by fixing an ellipse expressed by the formula (x / 12) 2+ (y / 4) 2 = 1 on a jigsaw divided into quarters. , 120 ml of blowing agent compound is injected into the desiccator, covered with a lid, and left to stand for 24 hours in a blowing agent atmosphere at 25 ° C. Then, the specimens were taken out and the specimens were bent on a cylinder having a diameter of 30 mm to calculate the critical strain or critical strain from the crack initiation position.

-Criteria for critical deformation: 0.3 or less = not available, 0.3 to 0.5 = available when the stress is very small, 0.5 to 0.8 = usable when the stress is small, 0.8 to 2.0 = usable even when the stress is large, 2.0 or higher = Can be used at very high stresses.

Since the resin composition of the present invention has the advantage that the chemical resistance is significantly increased while maintaining the mechanical properties equally, it can be effectively used to manufacture the inner parts of the refrigerator and molded parts for the refrigerator that require strong chemical resistance.

Claims (3)

98 to 70 parts by weight of acrylonitrile-butadiene-styrene (ABS) resin as a basic resin; 2-30 weight part of polyolefin compounds; And 10 to 30 parts by weight of a compound obtained by grafting acrylonitrile-styrene (SAN) to polyolefin as a compatibilizer; ABS resin composition having excellent chemical resistance, characterized in that it comprises. The resin of claim 1, wherein the compatibilizer is a resin obtained by grafting an acrylonitrile-styrene resin to a low density polyethylene (LDPE-g-SAN) and a resin obtained by grafting an acrylonitrile-styrene resin to a polypropylene (PP-g- SAN), a resin obtained by grafting acrylonitrile-styrene resin to ethylene vinyl acetate (EVA-g-SAN), or a mixed resin thereof, and the content of grafted acrylonitrile-styrene resin in these compatibilizer resins is 5 ABS resin composition excellent in chemical resistance, characterized in that ~ 70% by weight. The method according to claim 1, wherein the polyolefin compound is polyethylene wax, polypropylene wax, ethylene-propylene copolymer wax, oxidized polyethylene wax, oxidized polypropylene wax, oxidized ethylene-propylene copolymer wax, Selected from the group consisting of polyolefin waxes copolymerized with aromatic monomers, polyethylene, polypropylene, ethylene-propylene copolymers, oxidized polyethylene, oxidized polypropylene, oxidized ethylene-propylene copolymers, and polyolefins copolymerized with aromatic monomers ABS resin composition excellent in chemical resistance, characterized in that one or two or more.