JPH064753B2 - Impact-resistant resin composition having good thermal stability - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polymer composition having improved properties, and more specifically to a thermoplastic polyester,
A rubbery polymer mainly composed of conjugated diolefin, a copolymer of acrylonitrile, aromatic vinyl and acrylic acid ester graft-polymerized, and a mixture of epoxy resin with excellent heat resistance and high impact strength The present invention relates to a resin composition suitable for various industrial materials.

[Prior art and its problems]

Thermoplastic polyesters have long been consumed in large amounts as fibers and films, and among them, polyalkylene terephthalate has excellent technical properties such as mechanical strength such as rigidity and hardness, heat resistance, electrical properties, and resistance. In recent years, it has been used as a molding material in a wide range of fields such as electric and electronic device parts and automobile parts due to its solvent property and rapid processability.

However, these polyalkylene terephthalates as engineering plastics have a drawback that the impact strength when notched is insufficient, and by improving them, they can be used for wider applications. Therefore, many attempts have been made to improve such drawbacks.

That is, an attempt is made to improve the impact strength by mixing a modified elastomer or the like with polyalkylene terephthalate, for example, polybutylene terephthalate is mixed with a usual ABS resin composed of a conjugated diolefin, styrene, and acrylonitrile (Japanese Patent Publication No. 47). -30421) is known.

By the way, ordinary ABS resins greatly improve the impact strength of vinyl polymers such as vinyl chloride resin and polystyrene, but they are not very effective as impact modifiers of non-vinyl polymers, and in fact, the Japanese Patent Publication No. 47-30421. As seen in the publication, the impact strength of polybutylene terephthalate is hardly improved.

In addition, it has been proposed to add a modified elastomer as a means for improving the impact strength of polyalkylene terephthalate. However, although the impact strength is improved, other useful properties are significantly decreased, and the effect of the improvement is Often halved.

The present inventors have found in Japanese Patent Application No. 59-118233 a new impact resistant resin composition that solves this problem. However, since a rubbery polymer mainly composed of a conjugated diolefin is used as an elastomer mixed for imparting impact resistance, it is inferior in heat resistance during molding at high temperature,
I am still dissatisfied with the fact that the unique impact strength is not exhibited.

[Means for solving problems]

An object of the present invention is to impart excellent heat resistance and impact resistance without deteriorating the useful properties of the thermoplastic polyester represented by polyalkylene terephthalate.

That is, the inventors of the present invention have made extensive studies, and as a result, select a graft copolymer having a specific component and composition, and further prescribe the compounding ratio of this graft copolymer and polyalkylene terephthalate within a specific range. And by using a specific amount of the epoxy resin in combination, an impact resistant resin composition having excellent heat resistance and impact resistance is obtained,
It has been found that the object of the invention is achieved.

The present invention relates to 40 to 95% by weight of a rubbery trunk polymer mainly composed of a conjugated diolefin, and acrylonitrile,
Obtained by grafting 60 to 5% by weight of a monomer mixture consisting of aromatic vinyl and acrylic acid ester, the weight ratio of which is acrylonitrile: aromatic vinyl: acrylic acid ester = 5 to 50:20 to 60:20 to 60 5 to 50 parts by weight of the graft copolymer and 95 to 50 parts by weight of the thermoplastic resin polyester resin are uniformly mixed with 0.1 to 30 parts by weight of the epoxy resin per 100 parts by weight, and the heat resistance is excellent. The present invention relates to an impact polyester composition.

The greatest feature of the resin composition of the present invention is that the notched Izod impact strength corresponding to the notch sensitivity is extremely high even when the graft copolymer content of the composition is low. That is, even when the graft copolymerization ratio is low, the impact strength up to a minimum of −40 ° C. is remarkably improved, and the impact strength of the composition is remarkably improved with an increase in the graft copolymerization ratio. It is in. This is an extremely important feature from the point of providing excellent impact resistance while maintaining the other properties of polyalkylene terephthalate, which is the object of the present invention.

Surprisingly, the resin composition of the present invention is not only excellent in impact resistance but also excellent in heat resistance, that is, exposed to a molding processing temperature condition at a high temperature of 200 ° C. or higher for a relatively long time. Even if it is applied, the impact strength is extremely small. The notched Izod impact strength can be exerted not only at room temperature of 23 ° C. but also at a very low temperature of −40 ° C.

Thermoplastic polyester resins suitable for the purposes of the present invention include aromatic dicarboxylic acids or their reactive derivatives, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols or mixtures thereof. Is a reaction product of. A preferred thermoplastic polyester resin can be produced by known methods from terefuluric acid or its reactive derivative and an aliphatic or cycloaliphatic diol containing 2 to 10 carbon atoms.
Also preferred thermoplastic polyester resins are at least 80 mol%, preferably at least 90 mol% terephthalic acid residues based on the dicarboxylic acid component and at least 80 mol%, preferably at least 90 mol% based on the diol component. % Ethylene glycol and / or 1,4-butazinol residues.

In addition to the terephthalic acid residue, the thermoplastic polyester resin may contain up to 20 mol% of other dicarboxylic acids containing 3 to 14 carbon atoms or aliphatic dicarboxylic acids containing 4 to 12 carbon atoms. Contains residues of acids, such as phthalic acid, isofuric acid, naphthalene-2,6-dicarboxylic acid, 4,4-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid and cyclohexanediacetic acid it can.

In addition to the residues of ethylene glycol or 1,4-butanediol, the thermoplastic polyester resin contains up to 20 mol% of other aliphatic diols containing from 3 to 12 carbon atoms or from 6 to 21 carbon atoms. Containing a residue of a cycloaliphatic diol, 1,3-propanediol, 2-ethyl-1,3-propanediol, neopentyl glycol, 1.5-pentanediol, 1,6-hexanediol, cyclohexane- 1,4-dimethanol, 3-methyl-2,4-pentanediol, 2-methyl-2,4
-Pentanediol, 2,2,4-trimethyl-1,3
-Pentanediol, 2,2,4-trimethyl-1,6
-Pentanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5-hexanediol, 1,4-di- (β-hydroxyethoxy) -benzene, 2,2-bis- (4-
Hydroxycyclohexyl) -propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis- (3-β-hydroxyethoxyphenyl) -propane and 2,2-bis- (4 It can contain residues of -hydroxypropoxyphenyl) -propane.

Thermoplastic polyester resin is a relatively small amount of trivalent or tetravalent
It can be branched by incorporating a dihydric alcohol or a tri- or tetra-basic carboxylic acid. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane, trimethylolpropane and pentaerythritol. Based on the acid component,
It is appropriate to use a branching agent of not more than 1 mol%.

Particularly preferred thermoplastic polyester resins are terephthalic acid and its reactive derivatives such as dialkyl esters, and ethylene glycol and / or 1,
A polyalkylene terephthalate produced solely from 4-butanediol, and / or a mixture of these polyalkylene terephthalates.

Particularly preferred thermoplastic polyester resins include copolyesters prepared from at least two of the above-mentioned acid components and / or at least two of the above-mentioned alcohol components, and specifically, poly (ester glycol / 1,4-).
Butanediol) -terephthalate.

The rubbery trunk polymer mainly composed of the conjugated diolefin in the present invention is esterified with an α, β-ester unsaturated monomer other than polyvitadiene or butadiene, for example, styrene, acrylonitrile, or an alcohol having 1 to 4 carbon atoms. It is a butadiene-based copolymer obtained by copolymerizing acrylic acid ester or metacrylic acid ester. Pure polybutadiene is preferred as the backbone polymer.

The proportion of the rubbery trunk polymer in the graft copolymer in the present invention is 40 to 95% by weight, preferably 50 to 90% by weight, more preferably 60 to 80% by weight.
If the proportion of the trunk polymer in the graft copolymer is less than 40% by weight, the impact improving effect of the polyalkylene terephthalate, which is the object of the present invention, is insufficient.
If it exceeds 95% by weight, impact strength is improved, but other mechanical properties are deteriorated and heat resistance is deteriorated, which is not preferable.

The grafting monomers used in the present invention are acrylonitrile, aromatic vinyl and acrylic acid ester.
It is a mixture of different types. Among them, the acrylate ester preferably contains an alkyl group obtained by esterifying an alcohol having 6 carbon atoms modified, and examples thereof include methyl, ethyl, propyl, butyl, pentyl and hexyl acrylate esters. A substituted acrylic ester such as methyl methacrylate can also be used.

As the aromatic vinyl, styrene, α-methylstyrene and the like can be used, and styrene is preferable. Preferred grafting monomers are those consisting of acrylonitrile, styrene and methyl acrylate.

The weight ratio of each monomer in the graft monomer in the present invention is acrylonitrile: aromatic vinyl: acrylic ester = 5 to 50:20 to 60:20 to 60, preferably acrylonitrile: aromatic vinyl: acrylic ester = 15-40: 20-45: 45: 30
-55, more preferably acrylonitrile: aromatic vinyl: acrylic ester = 20-35: 25-40:
35-55. When the acrylonitrile content is out of the range, impact strength is lowered and the composition is colored, and when the aromatic vinyl content is out of the range, physical properties are deteriorated, which is not preferable. Further, when the acrylic ester content is out of the range, heat resistance and impact strength of the composition are also deteriorated, which is not preferable.

In addition to acrylonitrile, aromatic vinyl and acrylic acid ester, the grafting monomer in the present invention may be copolymerized with other vinyl monomers such as vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, methacrylic acid and its ester. May be included in small amounts.

The graft copolymer in the present invention is a known method, for example, by polymerizing a graft monomer in a latex of polybutadiene or a butadiene copolymer using a radical-forming polymerization initiator by an emulsion polymerization method or a latex suspension polymerization method,
It is obtained by coagulation and drying. Of course, the present invention can employ various manufacturing methods other than the above, and is not limited to a specific manufacturing method.

In the present invention, the blending ratio of the polyalkylene terephthalate and the graft copolymer is 5 to 50 parts by weight of the polyalkylene terephthalate and the blending ratio of the graft copolymer is 5 parts by weight.
To 50 parts by weight, preferably 15 to 45 parts by weight, and more preferably 20 to 40 parts by weight. In this case, the sum of the two is 100 parts by weight. When the content of the graft copolymer is less than 5 parts by weight, the impact strength of the composition is not significantly improved, and when it exceeds 50 parts by weight, other properties such as heat resistance and rigidity are deteriorated. It is not preferable because

On the other hand, the following various types are used as the epoxy resin used in the present invention. For example, bisphenol A type epoxy resin (Epiclon 85 manufactured by Dainippon Ink and Chemicals, Inc.
0, 1050, 3050, 7050, etc.), bisphenol F type epoxy resin, resin resin type epoxy resin,
Novolac type epoxy resin (manufactured by the same company, Epicron 74
0 or N-695 etc.), hydrogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, or various bromine- or chlorine-substituted epoxy resins thereof (for example,
Many known epoxy resins can be used, such as a polymer of tetrabrominated bisphenol A and epichlorohydrin). A particularly preferred epoxy resin is a bisphenol A type epoxy resin. These epoxy resins may be used alone or in combination of two or more.

A suitable amount of the epoxy resin used is 0.1 to 30 parts by weight of the epoxy resin based on 100 parts by weight of the total amount of the graft copolymer and the thermoplastic polyester. The preferred amount is 0.5 to 20 parts by weight. If the amount used is too small or too large, the heat resistance will deteriorate in the molding process at high temperature, and the impact strength will be greatly reduced.

The three methods of mixing the graft copolymer of the present invention, the thermoplastic polyester and the epoxy resin do not need to be special methods, and both are mixed by a suitable mixer such as a ribbon blender and supplied to an extruder to melt. The kneading, extruding into a string shape, cooling, cutting and forming a molding material are carried out by a usual method.

The temperature at the time of preparing the mixture is at least 10 ° C. higher than the melting point of the polyalkylene terephthalate and 300 ° C. or less, preferably 240 to 280 ° C.

Stabilizers, colorants, foaming agents, flame retardants, reinforcing agents such as glass fibers, various additives such as fillers are added to the composition of the present invention to improve performance, improve processability, and prevent deterioration. Various properties can be imparted as an industrial material or as a commercial product. The mixing method of these various additives is not particularly limited.

INDUSTRIAL APPLICABILITY The composition of the present invention is useful as an industrial material for automobile parts such as bumpers, outer covers for gasoline tank inlets, spoilers, and parts for electronic / electrical devices.

〔The invention's effect〕

The resin composition of the present invention is excellent in heat resistance and impact resistance, and has a well-balanced performance in other mechanical properties, solvent resistance and the like.

〔Example〕

The present invention will be further described below with reference to examples. Parts and% in the examples are based on weight unless otherwise specified.

Example 1 Graft copolymer powder obtained by graft-polymerizing 5% acrylonitrile, 5% styrene and 10% methyl acrylate in an emulsified state in the presence of 80% polyvitadiene latex (in terms of solid content), coagulating and drying. 25 parts of polybutylene terephthalate (PBT, phenol / tetrachloroethane = 6/4, intrinsic viscosity number [η] measured at 30 ° C.
= 1.13) 75 parts and 1 part of Epicron 850 (epoxy equivalent 190) manufactured by Dainippon Ink and Chemicals, which is a bisphenol A type epoxy resin, are mixed and extruded with a 40φ extruder equipped with a gourmet screw. Into pellets. Furthermore, after heating and drying these pellets, a molded product was molded with an in-line screw type 3 ounce injection molding machine (manufactured by Toshiba Machine) and the physical properties thereof were measured.

Notched Izod impact strength at 23 ° C (hereinafter II
Abbreviated) is 90 kg · cm / cm, II at -40 ° C: 40 kg · cm / cm
Met. Bending strength (hereinafter abbreviated as FS) 500 kg
・ Cm ² , flexural modulus (hereinafter abbreviated as FM) 1.4 × 10 ⁴ kg ・
It showed cm ² .

In the injection molding machine, the pellets were allowed to stay in the molten state at 250 ° C. for 15 minutes, and then the test piece at 23 ° C.
II was 89 kg · cm / cm and -40 ° C II was 35 kg · cm / cm.

Comparative Example 1 In Example 1, an experiment was performed under the same conditions except that the epoxy resin was not added. In this case, the initial II at 23 ° C is 90 kg · cm / cm and the II at −40 ° C is 40 kg · cm / cm, but 2
II at 23 ° C. after staying at 50 ° C./15 minutes: 14 kg · cm / cm,
II at −40 ° C .: It fell to 4 kg · cm / cm, and showed no practical value.

Example 2 Using the same polybutadiene latex as in Example 1, acrylonitrile / styrene / methyl methacrylate weight ratios of 25/25/50 were kept constant to prepare graft copolymers having different polybutadiene contents as shown in Table 1. According to Example 1, the composition of 30 parts of the graft copolymer, 70 parts of polybutylene terephthalate (PBT) and 1.5 parts of Epiclon 850 was measured for impact strength, and the results are shown in Table 1.

Example 3 In Example 1, 65 parts of PBT, graft copolymer 35
Parts and novolac type epoxy resin, Epichron N-695 (epoxy equivalent 240) from Dainippon Ink and Chemicals, Inc.
It was changed to 7 parts. The resulting molded article had a II at 23 ° C of 80 kg · cm / cm and a II at −40 ° C of 45 kg · cm / cm.
It showed cm. Also, II after retention in the injection molding machine under the conditions of 250 ° C / 15 minutes is 80 kg · cm / cm at −23 ° C and −40 ° C.
It was 43 kg · cm / cm.

Comparative Example 2 When the properties of PBT alone in Example 1 were measured, FS: 56
0 kg · cm ² , FM: 1.6 × 10 ⁴ kg · cm ² , 23 ° C II: 4 k
The impact strength was extremely low at g · cm / cm and -40 ° C II: 1 kg · cm / cm.

Example 4 30 parts of a graft copolymer composed of 80% polybutadiene, 8% acrylonitrile, 6% styrene, and 6% methyl acrylate, [η] 1.20 PBT, and tetrabrominated bisphenol A and diglycidyl ether of tetrabrominated bisphenol A. A molded article composed of 20 parts of a brominated epoxy resin having an epoxy equivalent of 5000 formed with and 5 parts of antimony trioxide has a II of 23 ° C .: 30 kg · cm / cm and a II of -40 ° C .: 1: 1.
It showed 0 kg · cm / cm. In addition, UL standard subject 94
The flame retardancy of (US standard) was V-0, which was the highest flame retardancy.

Example 5 20 parts of a graft copolymer composed of 80% polybutadiene, 2% acrylonitrile, 8% styrene, and 10% methyl methacrylate, 80 parts PBT of [η] 1.30, and a bisphenol A type epoxy resin manufactured by Dainippon Ink and Chemicals, Molded product formed on 7 parts of Epicron 1050 (epoxy equivalent 480) is FS: 550 kg · cm ² , FM: 1.5 ×
II of 10 ⁴ kg · cm ² and 23 ° C .: 70 kg · cm / cm and −40 ° C.
II: 30 kg · cm / cm, II after retention at 250 ° C / 15 minutes is 2
It was 65 kg · cm / cm at 3 ° C and 25 kg · cm / cm at −40 ° C.

Comparative Example 3 When the epoxy resin was not added in Example 5, the temperature was 23 ° C.
II: 75 kg · cm / cm, -40 ° C II: 35 kg · cm / cm, 2
After staying at 50 ° C for 15 minutes, II: 60 kg · cm / cm at 23 ° C,
It was 3 kg · cm / cm at −40 ° C.

Claims (1)

[Claims] 1. A rubbery trunk polymer comprising a conjugated diolefin as a main component and 40 to 95% by weight of acrylonitrile, aromatic vinyl and acrylic ester, the weight ratio of which is acrylonitrile: aromatic vinyl: acrylic acid. Ester = 5 to 50:20 to 60:20 to 60
0.1 to 30 parts by weight of an epoxy resin per 100 parts by weight of a total of 5 to 50 parts by weight of a graft copolymer obtained by grafting 60 to 5 parts by weight of a monomer mixture and 95 to 50 parts by weight of a thermoplastic polyester resin. An impact-resistant polyester composition having good thermal stability, which is obtained by uniformly mixing.