JPH0517677A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a resin composition which is excellent in stiffness and impact strength and gives a molding with good dimensional stability and heat resistance. CONSTITUTION:A thermoplastic resin composition which consists of 50-95wt.% aromatic polyester resin represented by polybutylene terephthalate and 50-52wt.% AES resin. The AES resin is a resin consisting of 100-5 pts.wt. graft polymer obtained by polymerizing an aromatic vinyl compound and a vinyl cyanide compound in the presence of an ethylene/propylene rubbery copolymer and 0-95 pts.wt. copolymer of an aromatic vinyl compound with a vinyl cyanide compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and more particularly to a thermoplastic resin composition which is excellent in rigidity and impact strength, and in which a molded product obtained is excellent in dimensional accuracy and heat resistance.

[0002]

BACKGROUND OF THE INVENTION Aromatic polyesters are generally thermoplastic materials having various excellent properties such as oxidation resistance and solvent resistance.
It is suitable for obtaining moldings with mechanical properties. However, aromatic polyester has dimensional stability due to its crystallinity, has low impact resistance, and high load (18.6 kg /
It has the disadvantage that the deflection temperature under load is low under cm ² .

Recently, as the products have become lighter, thinner, shorter, and smaller, the demand for materials having excellent dimensional stability, impact resistance, and heat resistance has increased.

The present inventors have made the
As a result of intensive studies aimed at further improving the characteristics, the present invention has been achieved.

[0005]

An object of the present invention is to provide a resin composition which is excellent in rigidity and impact strength, and is also excellent in dimensional stability and heat resistance when formed into a molded product.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, 50 to 95% by weight of an aromatic polyester resin (A) is polymerized with an aromatic vinyl compound and / or a vinyl cyanide compound in the presence of an ethylene-propylene rubbery copolymer. 100 to 5 parts by weight of the resulting graft polymer (I), an aromatic vinyl compound and /
Alternatively, it is a thermoplastic resin composition comprising 0 to 95 parts by weight of a copolymer (II) obtained by polymerizing a vinyl cyanide compound and 50 to 5% by weight of an AES resin (B).

The present invention will be described.

The aromatic polyester resin (A) used in the present invention is a polyester having an aromatic ring in the main chain of the polymer and comprises an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative. It is a polymer or copolymer containing a main component and obtained by a condensation reaction. Examples of the aromatic dicarboxylic acid component include dicarboxylic acids having a benzene nucleus such as terephthalic acid and isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-
Examples thereof include dicarboxylic acids having a naphthalene nucleus such as 2,7-dicarboxylic acid or ester-forming derivatives thereof.

In place of the aromatic dicarboxylic acid or its ester-forming derivative, a dicarboxylic acid other than the aromatic dicarboxylic acid, which is 20 mol% or less of the acid component, such as adipic acid, sebacic acid or their ester-forming derivative is used. can do. Examples of the diol component include aliphatic glycols such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol and cyclohexanedimethanol, 1,4
-A diol having an aromatic ring such as bisoxyethoxybenzene and bisphenol A, or an ester-forming derivative thereof can be applied. Polybutylene terephthalate is particularly preferable as the aromatic polyester.

The AES resin (B) used in the present invention is a graft polymer obtained by polymerizing an aromatic vinyl compound and a vinyl cyanide compound in the presence of an ethylene-propylene rubbery copolymer ( A resin comprising I) 100 to 5 parts by weight and a copolymer (II) obtained by polymerizing an aromatic vinyl compound and a vinyl cyanide compound, 0 to 95 parts by weight (the total AES resin is 100 parts by weight). ).

The ethylene-propylene rubbery copolymer which constitutes the AES resin is a binary copolymer (EPR) consisting of ethylene and propylene; a terpolymer (EPDM) consisting of ethylene, propylene and a non-conjugated diene. ) And the like, and one kind or two or more kinds can be used.

Examples of the non-conjugated diene in the terpolymer (EPDM) include dicyclopentadiene, ethylidene norbornene, 1,4-hexadiene, 1,4-cycloheptadiene and 1,5-cyclooctadiene. .

The molar ratio of ethylene and propylene in the binary copolymer (EPR) and the ternary copolymer (EPDM) is preferably in the range of 5: 1 to 1: 3. In the terpolymer (EPDM), the proportion of the non-conjugated diene is preferably in the range of 2 to 50 in terms of iodine value.

Graft polymer (I) and copolymer (II)
Examples of the aromatic vinyl compound that constitutes
-Methylstyrene, α-chlorostyrene, vinyltoluene and the like are mentioned, and styrene is particularly preferable. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable.

Further, the weight ratio of these compounds to the rubbery copolymer in the graft polymer (I) can be selected in an appropriate range depending on the purpose. Usually, a ratio of 5 to 70% by weight of rubber is preferable with respect to 95 to 30% by weight of the vinyl compound.

In the copolymer (II), other polymerizable monomer compounds can be added to the aromatic vinyl compound and the vinyl cyanide compound. Then, the graft polymer (I) and the copolymer (II) as the AES resin must satisfy the ratio (weight) in the above preferable range.

AES resin is a solution polymerization method, a bulk polymerization method,
It is produced by a known method such as a suspension polymerization method or an emulsion polymerization method.

The blending ratio of the thermoplastic resin composition of the present invention is such that the component (A) accounts for 50 to 95% by weight based on the entire composition.
And the component (B) must be blended so that the condition is 5 to 50% by weight. When the content of the component (A) is less than 50% by weight, the solvent resistance of the resulting composition is insufficient, while when the content of the component (A) exceeds 95% by weight, the dimensions of the resulting composition are It has poor stability and is insufficient for improving the deflection temperature under load. On the other hand, when the content of the component (B) exceeds 50% by weight, the solvent resistance of the obtained composition is poor.

Various additives (for example, various stabilizers, pigments, flame retardants, mold release agents, inorganic fillers) are contained in the composition of the present invention within a range not impairing the object of the present invention. May be.

As a method for preparing the thermoplastic resin composition of the present invention, any method for mixing solid substances (for example, a method using a Banbury mixer, a heating roll or a single-screw or twin-screw extruder) can be applied.

[0021]

The effects of the present invention will be described in more detail with reference to the following examples. In the examples, "%" is based on weight, impact strength is ASTM-256, and flexural modulus is AST.
M-790 and deflection temperature under load were measured by the method of ASTM-648. The dimensional accuracy was determined by measuring the molding shrinkage rate. Molding shrinkage rate (%) = [{(mold size)-(molded product size)} / (mold size)]
× 100 Solvent resistance was evaluated by a change in the surface after being immersed in toluene at 23 ° C for 7 days.

[0022]

Examples 1 to 4 and Comparative Examples 1 to 4 Polybutylene terephthalate (reduced specific viscosity 1.10) was added to AES shown below.
Various resins were prepared by uniformly mixing the resins at a ratio shown in Table 1 with a V-type blender. The obtained resin composition was melted and kneaded at a barrel temperature of 250 ° C. by a twin-screw extruder having a diameter of 44 mm, and the thread discharged from the die was cooled and cut to obtain respective molding pellets.

Next, these pellets were dried with hot air at 110 ° C. for 5 hours, then a test piece mold for measuring physical properties was attached to a 5 ounce injection molding machine, and a cylinder temperature was 260 ° C.
Mold temperature 40 ℃, injection pressure 700kg / cm ² , cooling time 2
A test piece was molded under the molding conditions of 0 second and a total cycle of 35 seconds.

The AES resin used (total 100 parts by weight) was obtained by kneading 48 parts by weight of the graft polymer obtained by the following method and 52 parts by weight of the copolymer with a Banbury mixer.

(Production of Graft Polymer (I)) EP containing iodine value of 8.5, Mooney viscosity of 61, propylene content of 43% by weight, and ethylidene norbornene as a diene component.
370 parts by weight of DM was dissolved in 3000 parts by weight of n-hexane and 1500 parts by weight of ethylene dichloride to give 25 parts by weight of styrene.
0 parts by weight of 130 parts by weight of acrylonitrile and 13 parts by weight of benzoyl peroxide were added, and polymerization was carried out at 67 ° 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 polymer (I) (rubber content about 49%).

(Production of Copolymer (II)) To 100 parts by weight of a solution obtained by mixing 70% by weight of styrene and 30% by weight of acrylonitrile, 0.1 part by weight of t-dodecyl mercaptan and 0.3 part by weight of benzoyl peroxide were added. Was added and the temperature was raised from 30 ° C. to 90 ° C. in an aqueous dispersion for 10 hours to carry out polymerization. After dehydration, a copolymer (II) was obtained. (Results of Examples and Comparative Examples)

[0027]

[Table 1]

As shown in Table 1, by adding an AES resin to polybutylene terephthalate, impact strength, heat resistance,
A well-balanced and high-quality molded product having excellent dimensional stability and solvent resistance can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08L 51/06 LLJ 7142-4J

Claims (2)

[Claims] 1. Aromatic polyester resin (A) 50 to 95
A thermoplastic resin composition comprising 50% by weight and 50 to 5% by weight of AES resin (B). Here, the AES resin is 100 to 5 parts by weight of a graft polymer (I) obtained by polymerizing an aromatic vinyl compound and / or a vinyl cyanide compound in the presence of an ethylene-propylene rubbery copolymer, and an aromatic compound. It is composed of 0 to 95 parts by weight of a copolymer (II) obtained by polymerizing a group vinyl compound and / or a vinyl cyanide compound. 2. The thermoplastic resin composition according to claim 1, wherein the aromatic polyester resin is polybutylene terephthalate.