JPH05125253A - Heat-resistant abs resin composition - Google Patents

Abstract

PURPOSE:To improve the surface impact strength and stretching ratio of an alpha-methylstyrene-modified ABS resin without detriment to its heat resistance and stiffness in practical use. CONSTITUTION:The title compsn. is prepd. by compounding 100 pts.wt. alpha- methylstyrene-modified ABS resin contg. 15-60wt.% alpha-methylstyrene with 0.5-3.0 pts.wt. ethylene copolymer prepd. by copolymerizing 40-90wt.% ethylene. 15-40wt.% 1-8C alkyl acrylate, 6-20wt.% carbon monoxide, and 0-20wt.% another vinyl monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant ABS resin composition, and more particularly to an ABS resin composition containing alpha methyl styrene which is excellent in surface impact strength and stretching ratio.

[0002]

PRIOR ART AND PROBLEM TO BE SOLVED BY THE INVENTION A containing acrylonitrile, butadiene and styrene as constituent components
The BS resin is a molding material having excellent rigidity, impact strength, elongation and fluidity, and is widely used for electrical, OA-related housings, interior / exterior of automobiles, and miscellaneous goods.
Among these, alpha methyl styrene-modified ABS resin obtained by substituting alpha methyl styrene for a part or all of styrene is used for applications requiring heat resistance. However, ABS with alpha methyl styrene
When the resin is modified, the surface impact strength and the draw ratio are reduced, which makes practical application difficult in some applications where performance requirements are severe.

In general, the impact applied when the actual molded product is put into practical use is often applied to the surface of the molded product. On the other hand, the most widely used to measure the impact strength of ABS resin is the Izod impact strength (with notch), but the Izod impact strength is the energy required to break the molded product by the impact from the lateral direction. It represents. Because of this, it cannot be said that the correspondence between the Izod impact strength and the practical impact strength is good. The alpha methyl styrene modified ABS resin has only a slight decrease in Izod impact strength due to alpha methyl styrene, but the surface impact strength is extremely low. As a result, the impact resistance in practical use becomes a problem. In this case, the surface impact strength is extremely important. Further, as a mechanism when the ABS resin breaks, it is generally known that the resin at a position where a shock is applied is stretched locally and then breaks. For this reason, in normal applications, the higher the draw ratio, the higher the reliability of the occurrence of fracture.

As described above, it is desired that the alpha-methylstyrene-modified ABS resin has improved surface impact strength and stretch ratio while maintaining good heat resistance. There is a method of increasing the content rate of butadiene rubber in order to improve the surface impact strength and the draw ratio, but heat resistance, rigidity, and fluidity are reduced, which is a practically large limitation. In addition, improvements with various additives have been tried, but it is hard to say that they have been successful in practice.

[0005]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an alpha-methylstyrene-modified ABS resin and ethylene having a specific composition ratio of 1 to 1 carbon atoms.
By mixing with a specific amount of an acrylate-carbon monoxide-based copolymer having an alkyl group of 8, the alpha-methylstyrene-modified ABS resin can be practically used without impairing the heat resistance and the rigidity, and the surface impact strength and the stretching rate. The present invention has been accomplished, and it was found that the improvement effect can be enhanced by incorporating a specific amount of polysiloxane or ethylenebisstearylamide. That is,
The present invention comprises (A) 40 to 90% by weight of ethylene, 15 to 40% by weight of acrylate having an alkyl group having 1 to 8 carbon atoms, 6 to 20% by weight of carbon monoxide, and 0 to 20% by weight of other vinyl monomer. Ethylene copolymer obtained by copolymerization 0.5 to 3.0 parts by weight, and (B) alpha methyl styrene content of 15 to 60
% By weight alpha-methylstyrene modified ABS resin
The present invention provides a heat resistant ABS resin composition comprising 100 parts by weight, and further comprising (C) based on the alpha methyl styrene modified ABS resin (B).
The present invention provides a heat-resistant ABS resin composition containing 50 to 3000 ppm of polysiloxane or 1000 to 20000 ppm of ethylenebisstearylamide.

A resin composition of 90 to 96% by weight of ABS resin and 4 to 10% by weight of ethylene-butyl acrylate-carbon monoxide copolymer is described in USP 4,985,497. -It is stated that the addition of carbon monoxide copolymer can improve the Izod impact strength without significantly impairing the rigidity and heat distortion temperature of the ABS resin. However, in this specification, there is no description about the alpha-methylstyrene-modified ABS resin, and there is no description about the problems such as surface impact strength and stretch ratio. Further, in USP 4,985,497, even if the ethylene-butyl acrylate-carbon monoxide copolymer is added in an amount of 4 to 10% by weight based on the total amount of the ABS resin, the lowering of the rigidity and the heat distortion temperature is considerably impaired. It is stated that there is no. However, when the present inventors mix the alpha methyl styrene modified ABS resin (B) and the acrylate-carbon monoxide type copolymer (A) having an ethylene-alkyl group having 1 to 8 carbon atoms, the ethylene-carbon number If the amount of the acrylate-carbon monoxide-based copolymer (A) having 1 to 8 alkyl groups is not less than 3.0% by weight based on the α-methylstyrene-modified ABS resin (B), the rigidity and heat resistance will decrease. It became clear, and it was found that there were large restrictions from a practical point of view.

The ethylene copolymer as the component (A) of the present invention comprises 40 to 90% by weight of ethylene, 15 to 40% by weight of an acrylate having an alkyl group having 1 to 8 carbon atoms, and 6 to 20% of carbon monoxide.
% By weight, if necessary, other vinyl monomer (V ₀ ) 0-20
It can be produced by copolymerization with a high-pressure radical polymerization method together with wt%. Examples of the acrylate having an alkyl group having 1 to 8 carbon atoms used in the present invention include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate,
Examples thereof include n-octyl acrylate, and n-butyl acrylate is particularly preferable. Other vinyl monomers (V ₀ ) used in the present invention include methyl methacrylate,
Typical examples are vinyl acetate, maleic anhydride, dibutyl fumarate, methacrylic acid, acrylic acid and glycidyl methacrylate. (A) The amount of ethylene in the component
If it is less than 40% by weight, the surface impact strength, rigidity and heat resistance will be unsatisfactory, and if it exceeds 90% by weight, the surface impact strength will be unsatisfactory. Further, when the amount of the acrylate having an alkyl group having 1 to 8 carbon atoms is less than 15% by weight, the surface impact strength becomes unsatisfactory, and when it exceeds 40% by weight, the surface impact strength, rigidity and heat resistance become unsatisfactory. Further, if the alkyl group of the acrylate has 9 or more carbon atoms, the surface impact strength becomes unsatisfactory.
If the amount of carbon monoxide is less than 6% by weight, the surface impact strength becomes unsatisfactory, and if it exceeds 20% by weight, the surface impact strength, rigidity and heat resistance become unsatisfactory.

The melt index of the ethylene copolymer as the component (A) is 0.1 to 100 at a temperature of 190 ° C. and a load of 2.16 kg.
A range of g / 10 minutes is preferred. The component (A) is the component (B).
0.5 to 3.0 parts by weight is used for 100 parts by weight. Here, if the amount of the component (A) is less than 0.5 parts by weight, the surface impact strength and the stretching ratio are hardly improved, and if it exceeds 3.0 parts by weight, the rigidity and the heat resistance are remarkably deteriorated, so that there is a large restriction in application. Become.

The component (B) of the present invention, which is an alpha-methylstyrene-modified ABS resin, is alpha-methylstyrene 20-70.
% By weight, 55 to 15% by weight of styrene, 15 to acrylonitrile
It is made by mixing a copolymer of 40% by weight and another vinyl monomer (V ₁ ) of 0 to 35% by weight with a graft rubber described below. Other vinyl monomers (V ₁ ) in this case include methyl methacrylate, methacrylonitrile,
Typical examples are methyl acrylate, dimethyl fumarate, dimethyl itaconate, maleic anhydride, phenylmaleimide, paramethylstyrene, tribromostyrene, dibromostyrene and the like. The graft rubber is a butadiene-based rubber latex, styrene, acrylonitrile, other vinyl monomer (V ₂ ) is added, butadiene-based rubber obtained by performing graft polymerization 30 to 80 wt%, styrene-acrylonitrile-based copolymer 70 to 20% by weight. The butadiene-based rubber in this case is a copolymer of polybutadiene or 50% by weight or more of butadiene and another vinyl monomer such as styrene, acrylonitrile, methyl methacrylate or butyl acrylate. The butadiene rubber is particles, and the particle size of the butadiene rubber particles is 0.2 to 0.5 μm on a weight average, and the particle size range is 0.05 to 2 μm.
Those which occupy 90% by weight or more are usually used. Typical other vinyl monomers (V ₂ ) are methyl methacrylate, methacrylonitrile, alphamethylstyrene, paramethylstyrene, maleic anhydride, diethyl maleate, phenyl maleimide, methacrylic acid and the like.

The content of alphamethylstyrene contained in the alphamethylstyrene-modified ABS resin (B) used in the present invention is 15 to 60% by weight. When the content of alpha methyl styrene is less than 15% by weight, heat resistance is insufficient, and when it exceeds 60% by weight, impact strength is insufficient. The (C) polysiloxane that can be used in the present invention has the following formula

[0011]

[Chemical 1]

(Wherein R represents a methyl group, a phenyl group or a hydrogen atom) means a polymer having a skeleton represented by the formula and substituted products thereof, wherein polydimethylsiloxane in which all R are methyl groups, and methyl as R Groups having both a phenyl group and a phenyl group, polymethylhydrogensiloxane having both a methyl group and a hydrogen atom as R, and modified polysiloxanes having various substituents at the molecular ends or in the middle of these polysiloxanes. For example, those having a group such as an amino group, a hydroxyl group, a carboxyl group, a mercapto group, an epoxy group, a polyoxyethylene group and a polyoxypropylene group are preferable, and polydimethylsiloxane is particularly preferable. The polysiloxane preferably has a viscosity at 25 ° C. of 100 to 60,000 centistokes. The amount of polysiloxane added is 50 based on the alpha methyl styrene modified ABS resin (B).
~ 3000 ppm, especially 100-2000 ppm is preferred. In this case, if the amount of polysiloxane added is less than 50 ppm, the effect of adding polysiloxane is not clear, and if it exceeds 3000 ppm, the rigidity is significantly reduced.

The amount of ethylenebisstearylamide which can be used in the present invention is 1000 to 20000 ppm, especially based on the alpha methyl styrene modified ABS resin (B),
2000-15000 ppm is preferred. In this case, when the amount of ethylenebisstearylamide added is less than 1000 ppm, the effect of improving the surface impact strength is poor, and when it exceeds 20,000 ppm, the rigidity is significantly reduced. The polysiloxane and the ethylenebisstearylamide may be used in combination, and the amount of the combination used is the same as described above.

The heat resistant ABS resin composition of the present invention is usually
It is produced by melt-mixing the components (A) and (B) and, if necessary, the component (C) with an extruder, a kneader, a roll or the like. In carrying out the present invention, the butadiene rubber is dissolved in a mixed monomer of styrene and acrylonitrile or a mixed monomer in which methylmethacrylate, alphamethylstyrene, phenylmaleimide or the like is further dissolved,
The salami type ABS resin obtained by polymerizing by solution polymerization, bulk polymerization, bulk suspension polymerization or the like is used as the heat resistant ABS of the present invention.
It may be mixed and used with a resin composition, and in this case, the addition amount of this salami type ABS resin is usually 200% by weight or less based on the component (B) of the present invention.

Known additives such as flame retardants, reinforcing fibers, fillers, antistatic agents, fluidity improvers, antioxidants, weather resistance improvers, lubricants and colorants are added to the heat resistant ABS resin composition of the present invention. The agent may be added, and various polymers such as polycarbonate, vinyl chloride resin, methyl methacrylate resin, polyamide resin, polyester resin, polyphenylene ether resin and the like may be added together with various known compatibilizers as necessary. it can.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method in the following examples is the molding temperature 2
Using a test piece molded at 40 ° C, the surface impact strength was determined by a falling ball impact test, and the test piece used was a square piece with a side length of 4.0 cm and a thickness of 3.4 mm, and the weight weight was 3 kg and the ballistic diameter was 16 mm. The result was expressed by the drop height at which the test piece breaks by 50%.
Also, Izod impact strength is ASTM D-256, unit is kg / c
m ² , tensile strength and draw ratio were according to ASTM D-638, units were kg / cm ² and%, respectively, and heat distortion temperature was according to ASTM D-648 (without annealing). The unit of melt index is g
Expressed in / 10 minutes. Unless otherwise specified, all parts and% are expressed on a weight basis.

Example 1 66 parts of a copolymer having a composition of 36% alpha methyl styrene, 36% styrene, 28% acrylonitrile and a melt index of 1.2, measured at 200 ° C. and a load of 5 kg,
And the graft rubber has a weight average particle size of 0.32 μm and
The content of polybutadiene such that particles having a particle size of 0.05 to 2.0 μm occupy 99% by weight is 50%, and the composition of the copolymer grafted on this is 73% styrene and 27% acrylonitrile. With a content of 50%
Alpha methyl styrene content of 34% by mixing 34 parts
Of 100 parts of alpha methyl styrene modified ABS resin, ethylene 66%, butyl acrylate 22%, carbon monoxide 12%, ethylene-based copolymer with melt index 8 measured at a load of 2.16 kg and a temperature of 190 ° C. The polymer was mixed in an extruder to form pellets. In this case, the amount of the ethylene-based copolymer was changed to 0, 1, 2.5 and 5 parts. As additives, 0.1 part of the phenolic antioxidant Irganox 1076 manufactured by Ciba Geigy, 0.3 part of trinonylphenyl phosphite, 0.1 part of distearyl thiodipropionate, and 0.15 part of calcium stearate were added. Then, the surface impact strength, the Izod impact strength, the tensile strength almost representing the rigidity, the stretching ratio, and the heat distortion temperature were measured. The measurement results are shown in Table 1.

[0018]

[Table 1]

Note) *: The improvement rate represents the improvement rate as compared with Experiment No. 1 in which the ethylene copolymer was not added. From the above results, the addition amount of ethylene-based copolymer was 1 part and
It can be seen that in the case of 2.5 parts, the surface impact strength was greatly improved by 30% and 80%, and the stretching ratio was 30% and 50%, respectively, as compared with Experiment No. 1. However, in view of the value of Izod impact strength, the improvement due to the addition of the ethylene-based copolymer is small, and the effect is lost. Also, it is understood that when the amount of the ethylene copolymer added is 5 parts (Experiment No. 4), the tensile strength and the heat distortion temperature are considerably lowered.

Example 2 62 parts of a copolymer having a composition of 50% alpha methyl styrene, 22% styrene, 28% acrylonitrile and a melt index of 0.7 measured at 200 ° C. and a load of 5 kg and used in Example 1 and Example 1 100 parts of alpha-methylstyrene-modified ABS resin having an alpha-methylstyrene content of 31% mixed with 38 parts of the same graft rubber, 2 parts of the same ethylene copolymer used in Example 1 and the same as in Example 1. The additives were mixed in an extruder to form pellets. Next, physical properties were measured in the same manner as in Example 1. The surface impact strength was 50 cm, the Izod impact strength was 16, the tensile strength was 410, and the stretching ratio was 1
3. The heat distortion temperature was 97 ℃. On the other hand, as a result of performing the same experiment without adding the ethylene copolymer (comparative example), the surface impact strength is 30 cm, the Izod impact strength is 16, and the tensile strength is 420.
The stretching ratio was 9 and the heat distortion temperature was 98 ° C.

Example 3 Example 1 except that 0.10 parts of polydimethylsiloxane having a viscosity of 500 centistokes at 25 ° C. was added.
Experiments were performed in the same manner as Experiment No. 1 and Experiment No.
The results corresponding to the experiment number 1 (comparative example) were a surface impact strength of 50 cm, an Izod impact strength of 22, a tensile strength of 430, a stretching ratio of 10 and a heat deformation temperature of 93 ° C. The result in the case of conforming to is that the surface impact strength is 100 cm or more,
The Izod impact strength was 22, the tensile strength was 405, the stretching ratio was 18, and the heat distortion temperature was 92 ° C.

Example 4 Experiments were carried out in the same manner as Experiment No. 1 and Experiment No. 3 of Example 1 except that 1.0 part of ethylenebisstearylamide was added. In the case of corresponding to Experiment No. 1 (comparative example), the results are a surface impact strength of 50 cm, an Izod impact strength of 22, a tensile strength of 430, a stretching ratio of 10 and a heat deformation temperature of 93 ° C. The result of (Example of the present invention) is the surface impact strength.
The Izod impact strength was 23, the tensile strength was 420, the stretching ratio was 17, and the heat distortion temperature was 93 ° C. From the results of Example 3 and Example 4, it can be seen that the combined use of polydimethylsiloxane or ethylenebisstearylamide shows a further improved effect on the surface impact strength and the stretching ratio.

Claims (2)

[Claims] 1. (A) 40 to 90% by weight of ethylene, 1 to 8 carbon atoms
15-40% by weight of acrylate having alkyl group, 6-20% by weight of carbon monoxide, 0-20% by weight of other vinyl monomer
Ethylene copolymer obtained by copolymerizing 0.5 to 3.0
Parts by weight, and (B) alpha methyl styrene content of 15 ~
60% by weight alpha methyl styrene modified ABS resin
A heat-resistant ABS resin composition comprising 100 parts by weight. 2. Alpha-methylstyrene-modified ABS resin
The heat-resistant ABS resin composition according to claim 1, further comprising (C) polysiloxane (50 to 3000 ppm) or ethylenebisstearylamide (1000 to 20000 ppm) based on (B).