JPH06248140A - Heat-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in heat decomposition resistance, impact resistance and processability by adding a specified compound to a composition comprising a plurality of specified copolymers. CONSTITUTION:1-5 pts.wt. compound of the formula (wherein R<1> is H or CH3; R<2> and R<3> are each 1-9 C alkyl; and R<4> is R<1>) is added to 100 pts.wt. composition comprising 10-60wt.% graft copolymer prepared by polymerizing 70-20wt.% monomer mixture comprising 20-80wt.% aromatic vinyl compound (e.g. styrene), 0-35wt.% acrylonitrile and 0-25wt.% other vinyl compounds copolymerizable therewith in the presence of 30-80wt.% rubbery polymer (e.g. polybutadiene) and 90-40wt.% copolymer comprising 40-80wt.% alpha-methylstyrene, 10-35wt.% acrylonitrile and 0-35wt.% other vinyl compounds copolymerizable therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant thermoplastic resin composition having remarkably improved resistance to thermal decomposition during heating such as granulation and molding.

[0002]

2. Description of the Related Art Rubber-reinforced styrene resins represented by ABS resins and AES resins are used in a wide range of fields because of their good moldability and good balance of physical properties.
In addition, in applications such as automobiles and electric appliances, which require a particularly high heat distortion temperature, a heat-resistant resin containing an α-methylstyrene-acrylonitrile copolymer has been in demand.

However, these heat-resistant resins have a higher heat distortion temperature as the amount of α-methylstyrene in the copolymer constituting the matrix increases, but on the other hand, at the time of heating during granulation, molding, etc. It has a drawback that it easily undergoes thermal decomposition.

On the other hand, a method has been proposed in which a heat-resistant resin containing an α-methylstyrene-acrylonitrile copolymer is blended with a hindered phenol compound having a molecular weight of 500 or more to increase the thermal decomposition temperature (Japanese Patent Publication No. 58-56578). issue)
However, it is not so effective in improving the thermal decomposition resistance during granulation and molding, and the heat distortion temperature is also lowered.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies as to a method for improving the thermal decomposition resistance during heating such as granulation and molding without lowering the heat distortion temperature. The present invention has been reached.

That is, the present invention provides a rubber-like polymer 30-8.
In the presence of 0% by weight, 70 to 20% by weight of a monomer mixture consisting of 20 to 80% by weight of styrene, 0 to 35% by weight of acrylonitrile and 0 to 25% by weight of another vinyl compound copolymerizable with them is polymerized. 10-60% by weight of the graft copolymer (A) and α-methylstyrene 4
Copolymer (B) consisting of 0 to 80% by weight, acrylonitrile of 10 to 35% by weight, and other vinyl compound copolymerizable with them of 0 to 35% by weight, relative to 100 parts by weight of a composition consisting of 90 to 40% by weight. The present invention provides a heat resistant thermoplastic resin composition comprising 0.01 to 5 parts by weight of a compound represented by the following general formula.

[0007]

[Chemical 2]

(In the formula, R ¹ represents hydrogen or a methyl group, R ² and R ³ independently represent an alkyl group having 1 to 9 carbon atoms, and R ⁴ represents hydrogen or a methyl group.)

The present invention will be described in detail below.

Graft copolymer (A) in the present invention
Comprises 20 to 80% by weight of an aromatic vinyl compound, 0 to 35% by weight of acrylonitrile, and 0 to 25% by weight of another compound copolymerizable therewith in the presence of 30 to 80% by weight of the above rubbery polymer. Monomer mixture 70 to 20% by weight
It is obtained by polymerizing. When the composition of the graft copolymer (A) is out of the above range, the balance between impact resistance and workability is poor, which is not preferable.

The rubber-like polymer constituting the graft copolymer (A) is a conjugated diene rubber such as polybutadiene, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-non-conjugated diene rubber. Examples thereof include ethylene-propylene rubbers, and acrylic ester rubbers such as polybutyl acrylate. A conjugated diene rubber is particularly preferable.

Examples of the aromatic vinyl compound constituting the graft copolymer (A) include styrene, α-methylstyrene, vinyltoluene and the like. Furthermore, as other vinyl compounds copolymerizable with these,
Examples thereof include unsaturated carboxylic acid alkyl ester compounds such as methyl acrylate, methyl methacrylate and glycidyl methacrylate, and maleimide compounds such as maleimide, N-phenylmaleimide and N-cyclohexylmaleimide.

The method for polymerizing the graft copolymer (A) is not particularly limited and can be obtained by known polymerization methods such as emulsion polymerization method, suspension polymerization method, solution polymerization method and bulk polymerization method.

The copolymer (B) in the present invention comprises 40 to 80% by weight of α-methylstyrene and 10 to acrylonitrile.
It is obtained by polymerizing a monomer mixture consisting of 35% by weight and 0 to 35% by weight of another vinyl compound copolymerizable therewith. Α-methylstyrene in the copolymer (B) is 4
If it is less than 0% by weight or acrylonitrile exceeds 35% by weight, the heat resistance of the copolymer is inferior, and if α-methylstyrene exceeds 80% by weight or acrylonitrile is less than 10% by weight, the polymerizability is inferior. Is not preferable.

Examples of the other copolymerizable vinyl compound in the copolymer (B) include the compounds exemplified in the graft copolymer (A) and styrene.

Further, the polymerization method of the copolymer (B) is not particularly limited, and it can be obtained by a known polymerization method such as emulsion polymerization method, suspension polymerization method, solution polymerization method and bulk polymerization method.

The composition ratio of the graft copolymer (A) and the copolymer (B) is such that the graft copolymer (A) is 10
60% by weight and 90 to 40% by weight of the copolymer (B). When the content of the graft copolymer (A) is less than 10% by weight, impact resistance is poor, and when it exceeds 60% by weight, heat resistance is poor, which is not preferable.

In the present invention, it is possible to substitute a part of the α-methylstyrene-acrylonitrile copolymer (B) with the styrene-acrylonitrile copolymer (C). Is intended for a heat resistant resin composition containing the α-methylstyrene-acrylonitrile copolymer (B), and the effect of the present invention can be obtained as the blending amount of the copolymer (C) increases. Since the expression tends to decrease, the blending amount of the copolymer (C) is preferably 50% by weight or less based on the total amount of the copolymer (B) and the copolymer (C).

In the present invention, the composition comprising the graft copolymer (A) and the copolymer (B) is
A compound represented by the following general formula is blended.

[0020]

[Chemical 3]

(In the formula, R ¹ represents hydrogen or a methyl group, R ² and R ³ each independently represent an alkyl group having 1 to 9 carbon atoms, and R ⁴ represents hydrogen or a methyl group.)

In the compound represented by the above general formula used in the present invention, R ² is an alkyl group having 1 to 9 carbon atoms, and among them, an alkyl group having 4 to 8 carbon atoms is preferable, and quaternary carbon is benzene. More preferred are alkyl groups attached to the ring, such as t-butyl, t-amyl and t-octyl. R ³ is an alkyl group having 1 to 9 carbon atoms, among which an alkyl group having 1 to 6 carbon atoms is preferable, and particularly preferable are methyl, ethyl, t-butyl and t-.
It's Amil.

Specific preferred examples of the compound represented by the above general formula are as follows. 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-butyl-6- [1- (3,
5-di-t-butyl-2-hydroxyphenyl) ethyl] phenyl acrylate, 2,4-di-t-amyl-6- [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl ] Phenyl acrylate, 2-t
-Butyl-6- (3-t-butyl-2-hydroxy-5
-Methylbenzyl) -4-methylphenyl methacrylate, 2,4-di-t-amyl-6- [1- (3,5-
Di-t-amyl-2-hydroxyphenyl) ethyl] phenyl methacrylate.

The compound represented by the above general formula in the present invention is 0.01 parts by weight based on 100 parts by weight of the composition comprising the graft copolymer (A) and the copolymer (B).
~ 5 parts by weight are blended. If the compounding amount of the compound is less than 0.01 parts by weight, the effect of improving the thermal decomposition resistance is not sufficient, and if it exceeds 5 parts by weight, there is no further improving effect, which is economically disadvantageous.

In the present invention, if necessary, other additives such as other phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, ultraviolet absorbers, hindered amine-based light stabilizers, lubricants, etc. , Pigments, dyes, flame retardants,
You may mix | blend a foaming agent, a reinforcing material, an inorganic filler, etc.

[Examples] The present invention is described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, parts and% in the examples
Is based on weight unless otherwise noted.

The compounds used in the examples are as follows, and are shown by the respective symbols below.

I-1: 2,4-di-t-amyl-6-
[1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate I-2: 2-t-butyl-6- (3-t-butyl-2-
Hydroxy-5-methylbenzyl) -4-methylphenyl acrylate AO-1: n-octadecyl-3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate AO-2: 4,4'-butylidene bis (3-methyl-6)
-T-butylphenol) AO-3: 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene AO-4: 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,1
0-tetraoxaspiro [5.5] undecane

Graft Copolymer A-1 60 parts of polybutadiene latex (solid content), 200 parts of water, 0.1 part of ethylenediaminetetraacetic acid disodium salt, 0.001 part of ferric sulfate and sodium in a reactor substituted with nitrogen. After adding 0.4 parts of formaldehyde sulfoxylate and heating to 60 ° C., 13 parts of acrylonitrile, 27 parts of styrene and 0.2 parts of cumene hydroperoxide.
The mixture consisting of parts was continuously added over 3 hours, and the mixture was further polymerized at 60 ° C. for 2 hours. Then, after salting out and drying, a graft copolymer A-1 was obtained.

Graft copolymer A-2 200 parts of ethylene-propylene-ethylidene norbornene copolymer (iodine value 8.0, Mooney viscosity 55, propylene content 40%) 200 parts n-hexane 3000 parts and ethylene dichloride 1500 parts Dissolved in styrene 300
Part, acrylonitrile (150 parts) and benzoyl peroxide (11 parts) were added, and the mixture was polymerized at 65 ° C. for 10 hours in a nitrogen atmosphere. The polymerization liquid was brought into contact with a large excess of methanol, and the deposited precipitate was separated and dried to obtain a graft copolymer A-2.

Copolymer B-1 Nitrogen-substituted reactor in which 150 parts of water in which 3.0 parts of sodium lauryl sulfate and 0.3 parts of potassium persulfate are dissolved is added 72 parts of α-methylstyrene, 28 parts of acrylonitrile and n- After adding 40% of a mixture of 0.4 parts of dodecyl mercaptan and polymerizing at 70 ° C for 1 hour, 60% of the remaining monomer mixture was continuously added at 70 ° C for 3 hours. Then, the mixture was aged at 70 ° C. for 2 hours to complete the polymerization. After salting out, dehydration and drying, a copolymer B-1 was obtained.

Copolymer B-2 150 parts of water in which 3.0 parts of sodium lauryl sulfate, 0.7 parts of potassium persulfate and 0.1 part of n-dodecyl mercaptan are dissolved is added to a reactor in which nitrogen is replaced, and the mixture is heated to 70 ° C. After heating, a monomer mixture consisting of 78 parts of α-methylstyrene and 5 parts of acrylonitrile was added, and polymerization was carried out at 70 ° C. for 1 hour. Then, acrylonitrile 1 at 70 ℃
7 parts were continuously added over 6 hours, polymerization was carried out, and further aging was carried out at 70 ° C. for 3 hours. After salting out, dehydration and drying, a copolymer B-2 was obtained.

Copolymer B-3 70 parts of styrene, 30 parts of acrylonitrile and 30 parts of t-dodecyl mercaptan are dissolved in 150 parts of water prepared by dissolving 1.5 parts of sodium lauryl sulfate and 0.3 part of potassium persulfate in a reactor substituted with nitrogen. A monomer mixture consisting of 0.3 parts was added and the mixture was polymerized at 65 ° C. After salting out, dehydration and drying, a copolymer B-3 was obtained.

[0034]

Examples 1 to 7 and Comparative Examples 1 to 9 The above compounds, graft copolymers A-1 and A-2, copolymers B-1 and B
-2 and B-3 with the compounding ratio shown in Table 1 is 40 mm
Was supplied to the extruder with a vent and granulated at 240 ° C. to obtain pellets. After drying the obtained pellets, a 90 × 50 × 3 mm flat plate and each test piece were molded by a 5.5 ounce injection molding machine set at a cylinder temperature of 250 ° C.

Thermal decomposition resistance The amount of residual acrylonitrile remaining in the pellet after granulation and in the flat plate after molding was measured by gas chromadraf, and the amount of residual acrylonitrile (PPM) increased by injection molding was measured, and the thermal decomposition resistance was measured. The sex was evaluated.

Impact Resistant Notched Izod (ASTM D-256) 1/4
Inch, 23 ℃

The workability Koka type flow tester ^{(230 ℃, 60kg / cm 2} )

Heat resistance Heat distortion temperature (ASTM D-648) 1/4 inch thick,
18.6 kg / cm ² load, no annealing. The results of these evaluations are shown in Table 1.

[0039]

[Table 1]

[0040]

Industrial Applicability The resin composition obtained by the present invention is excellent in thermal decomposition resistance at the time of heating during granulation, molding, etc., without causing a decrease in heat distortion temperature, and has impact resistance and workability. It has an excellent balance of physical properties and is suitable for various applications.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 51/06 LLH 7308-4J 55/02 LMC 7308-4J LME 7308-4J

Claims (1)

[Claims] 1. In the presence of 30 to 80% by weight of a rubbery polymer, 20 to 80% by weight of an aromatic vinyl compound, 0 to 35% by weight of acrylonitrile, and 0 to 25% by weight of another vinyl compound copolymerizable therewith. % Monomer mixture 70
To 20% by weight of a graft copolymer (A) 1
0-60% by weight and α-methylstyrene 40-80
Composition 1 consisting of 90% to 40% by weight of a copolymer (B) consisting of 10% to 35% by weight of acrylonitrile and 0% to 35% by weight of another vinyl compound copolymerizable therewith.
0.0 parts by weight of the compound represented by the following general formula 0.0
A heat resistant thermoplastic resin composition comprising 1 to 5 parts by weight. [Chemical 1] (In the formula, R ¹ represents hydrogen or a methyl group, R ² and R ³ each independently represent an alkyl group having 1 to 9 carbon atoms, and R ⁴ represents hydrogen or a methyl group.)