JPH04359959A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. which crystallizes sufficiently even in a low-temp. metal mold and is excellent in moldability, physical properties, surface gloss, etc., by compounding a specific polyester resin, a polyalkylene glycol and/or an epoxy compd., and a PP resin, each in a specified amt. CONSTITUTION:A polyester resin comprising a specified amt. of polyethylene terephthalate having a specified intrinsic viscosity and a specified content of ethylene terephthalate repeating units and a specified amt. of polybutylene terephthalate having a specified intrinsic viscosity and a specified content of butylene terephthalate repeating units, a polyalkylene glycol of formula l (wherein R1 and R'1 are each H, alkyl, or phenyl; R2 is 2-4C alkylene; and n is 5-10) or its deriv. and/or an epoxy compd. of formula II (wherein R is 2-4C alkylene; and m is 1-100), and a maleic-anhydride-modified PP resin obtd. by copolymerizing a specified amt. of maleic anhydride with a PP resin contg. a specified amt. of propylene are compounded, each in a specified amt.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a polyester resin composition having excellent moldability and physical properties.
The present invention relates to a polyester resin composition that has a high crystallization rate even when molded in a mold at a low temperature of 00° C. or lower, and can obtain excellent surface gloss, mechanical strength, toughness, etc.

0002

[Prior art] Polyethylene terephthalate resin (PE
T) has excellent heat resistance, chemical resistance, mechanical properties, electrical properties, etc., and is used in many industrial applications as fibers and films.

On the other hand, in injection molding for plastic applications, the crystallization rate is low in low-temperature molds of 100°C or less, so molding is performed in high-temperature molds of 130 to 150°C, which is economically disadvantageous and has a major practical drawback. It became. Generally, injection molding is performed at a mold temperature of 100° C. or lower, so there is a strong desire to increase the crystallization rate of PET at low temperatures, and various patents related to crystallization promotion have been proposed. Japanese Patent Publication No. 47-3027 proposes a method of mixing gypsum or talc and polyalkylene glycol with a polyester resin. Furthermore, JP-A-54-158452 discloses that a sodium or potassium salt of a long-chain aliphatic carboxylic acid or a sodium or potassium salt of an organic polymer having a pendant carboxyl group and an aromatic carboxylic acid ester are added to PET. A method of mixing has been proposed. PET obtained by the former method has improved moldability compared to ordinary PET, but the improvement effect is insufficient, so
If molded in a mold at temperatures below ℃, the appearance and physical properties of the molded product will be poor. In addition, PET obtained by the latter method can be molded using a mold at 100°C or lower, but additives tend to evaporate during molding, resulting in disadvantages such as poor appearance of molded products and mold stains. are doing.

0004

[Problems to be Solved by the Invention] The present inventors have completed the present invention as a result of intensive research in order to solve the above-mentioned drawbacks. It is an object of the present invention to provide a polyester resin composition which is sufficiently crystallized even in a mold, has excellent moldability and physical properties, and has excellent surface gloss.

[0005]

[Means for Solving the Problems] That is, the first aspect of the present invention is (
A) 50 to 95 parts by weight of polyethylene terephthalate having an intrinsic viscosity of 0.4 or more and containing 80 mol% or more of ethylene terephthalate repeating units, and (B) 80 mol% or more having an intrinsic viscosity of 0.5 or more. Polybutylene terephthalate containing the above butylene terephthalate repeating units 5~
(a) 1 to 20 parts by weight of a polyalkylene glycol or its derivative represented by chemical formula 3 and/or an epoxy compound represented by chemical formula 4 to 100 parts by weight of a polyester resin consisting of 50 parts by weight;

[Chemical formula 3] (However, R1 and R1' are hydrogen, alkyl group, phenyl group, R2 is alkylene group having 2 to 4 carbon atoms, n = 5 to
100)

[Formula 4] (However, R is an alkylene group having 2 to 4 carbon atoms, m = 1 to 1
00) (b) 0.1 part by weight of maleic anhydride in 100 parts by weight of polypropylene resin containing 80 mol% or more of propylene component
This is a polyester resin composition composed of 1 to 15 parts by weight of a maleic anhydride-modified polypropylene resin obtained by copolymerizing 5 parts by weight.

The second aspect of the present invention is a polyester resin composition characterized in that the polyester resin composition contains glass fiber and/or an inorganic filler.

Even when the composition of the present invention is molded in a mold at a low temperature of 100° C. or lower, it can provide molded products with very good surface gloss and excellent mechanical strength and toughness.

[0008] The polyethylene terephthalate (A) used in the present invention is 80 mol% or more, preferably 90 mol%
This is a polyester resin consisting of the above ethylene terephthalate repeating units. As the copolymerization component, a known acid component and/or glycol component can be used. For example, copolymerization components include isophthalic acid, naphthalene 1,4- or 2-
, 6-dicarboxylic acid, diphenyl ether 4,4'-dicarboxylic acid, adipic acid, sebacic acid,
Glycol components such as propylene glycol, butylene glycol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, 2,2'-bis(4-hydroxyphenyl)propane, p-oxybenzoic acid, p-hydroxyethoxybenzoic acid, etc. Examples include oxyacids. In addition, polyethylene terephthalate (A) has an intrinsic viscosity (value measured at 30°C in a mixed solvent of phenol/tetrachloroethane (6/4 weight ratio)) of 0.
．． It is 4 or more, preferably 0.5 or more.

The polybutylene terephthalate (B) used in the present invention is 80 mol% or more, preferably 90 mol%
This is a polyester resin consisting of the above butylene terephthalate repeating units. Examples of copolymerization components include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, aliphatic glycols, aromatic glycols, alicyclic diols, and oxyacids. In addition, polybutylene terephthalate (B) has an inherent viscosity (phenol/tetrachloroethane (6/4 weight ratio)
(value measured at 30°C in a mixed solvent) is 0.5 or more, preferably 0.7 or more.

The polyester resin composition used in the present invention contains the above polyethylene terephthalate (A) 50 to 95
The main component is 5 to 50 parts by weight of polybutylene terephthalate (B). Polybutylene terephthalate is 5
If it is less than 50 parts by weight, the effect of promoting crystallization will be small, and if it exceeds 50 parts by weight, heat resistance will decrease.

[0011] The polyalkylene glycol represented by formula 3 or its derivatives used in the present invention include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and their mono- or dialkyl ethers,
Examples include derivatives such as mono- or diphenyl ether and phenyl alkyl ether. In chemical formula 3, n=5 to 10
0, preferably n=5-50. If n is less than 5, it is highly volatile and therefore tends to evaporate during molding, resulting in poor appearance of the molded product. On the other hand, when it exceeds 100, the effect of promoting crystallization decreases.

The epoxy compounds represented by the formula 4 used in the present invention include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, diglycidyl ether of ethylene glycol/propylene glycol copolymer, and polytetramethylene glycol diglycidyl ether. Examples include glycidyl ether. m=1-100, preferably m=3-50. When m exceeds 100, the effect of promoting crystallization decreases.

[0013] The polyalkylene glycol or its derivative and the epoxy compound may each be used alone, or two
More than one species may be used in combination. The amount of polyalkylene glycol or its derivative and/or epoxy compound (a) added is 1 to 20 parts by weight per 100 parts by weight of the polyester resin.
Parts by weight, preferably 1 to 15 parts by weight. 1
If it is less than 20 parts by weight, the effect of promoting crystallization will be small, and if it exceeds 20 parts by weight, the physical properties will deteriorate.

The maleic anhydride-modified polypropylene resin (b) used in the present invention can be easily produced by selecting an appropriate method from known methods. For example, a method may be mentioned in which polypropylene resin (pp) and maleic anhydride are melt-kneaded in the coexistence of a radical generator. As pp,
In addition to homopolymers, random or block copolymers with other olefins containing 80 mol% or more of a propylene component can also be used. Known organic peroxides can be used as the radical generator, and specific examples include di-te
Examples include rt-butyl peroxide, benzoyl peroxide, dicumyl peroxide and the like.

The amount of maleic anhydride added is 0.1 to 5 parts by weight per 100 parts by weight of pp. If it is less than 0.1 part by weight, the effect of improving the appearance of the molded product by maleic anhydride-modified pp is small, and if it exceeds 5 parts by weight, defects such as coloring will occur. The amount of the radical generator is usually 0.01 to 1.0 parts by weight per 100 parts by weight of pp. The amount of maleic anhydride-modified pp(b) is 1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyester resin. If it is less than 1 part by weight, the surface gloss will be poor, and if it exceeds 15 parts by weight, the physical properties will be deteriorated.

In the present invention, it is preferable to use glass fiber in combination because mechanical strength and heat resistance are improved. The glass fibers used in the present invention may be ordinary glass fibers used for reinforcing polyester, and either roving type or chopped strand type can be used. The fiber length is preferably about 0.1 to 6 mm, and the diameter is 3
~30 μm is preferred. It is preferable that the glass fiber be subjected to a treatment such as silane treatment, titanate treatment, or chromium treatment for the purpose of improving adhesion to plastics. The sizing agent for glass fibers is preferably an epoxy compound that is often used for glass fibers for polyester resins.

The inorganic fillers used in the present invention are talc,
Clay, kaolin, mica, asbestos, silica, gypsum,
These include calcium silicate, graphite, wollastonite, and shirasu balloon.

The amount of glass fiber blended is usually 0 to 50% by weight based on the total composition, and the blended amount of the inorganic filler is 0 to 60% by weight based on the total composition. The total amount of both is preferably 20 to 60% by weight based on the total composition.

In the present invention, crystallization is further promoted when a conventional crystallization nucleating agent is used in combination. Crystallization nucleating agents include talc, clay, kaolin, asbestos, silicates, benzophenone, acetylacetone metal chelate, benzoic acid metal salts, benzoic acid esters, terephthalic acid metal salts, terephthalic acid esters, stearic acid metal salts, and montanic acid metal salts. , montanic acid ester, etc. Its compounding amount is usually 0.1 parts by weight per 100 parts by weight of polyester resin.
~5 parts by weight.

[0020] For producing the polyester composition of the present invention,
A conventional single-screw or twin-screw extruder may be used, and known kneading methods and conditions may be used.

In addition to the above-mentioned components, the composition of the present invention contains additives commonly used in polyester resins, such as colorants, mold release agents, antioxidants, heat stabilizers, ultraviolet absorbers, and ultraviolet stabilizers. , plasticizers, lubricants, flame retardants, antistatic agents, metal powders, etc. may be used depending on the purpose.

[0022]

[Examples] The contents of the present invention will be specifically explained below using examples. In addition, "part" and "%" in the examples indicate parts by weight and weight %.

[0023] Also, the composition was evaluated by the following method. The appearance of the molded product was evaluated based on the surface gloss and flow pattern of a disc with a diameter of 100 mm and a thickness of 3 mm. ◎Very good, ○Good, △Slightly poor,
×Defective. Mechanical strength, bending strength, and elastic modulus were measured according to ASTM D-790. Toughness Izod impact strength (notched) is ASTM D-2
It was measured according to No. 56.

Example 1 Polyethylene terephthalate (P) with an intrinsic viscosity of 0.65
ET) (manufactured by Kanebo Co., Ltd., TK-3) 60 parts, intrinsic viscosity 0
．． 8 polybutylene terephthalate (PBT) (Kanebo (
Co., Ltd., polyethylene glycol diglycidyl ether (Denacol EX-8) with an average molecular weight of 600 to 100 parts by weight of a polyester resin consisting of 40 parts of PBT71)
41, Nagase Sangyo) 2.5 parts, Montanic acid ester 0.5
1% of maleic anhydride/5 parts of modified pp modified with 1%/pp of maleic anhydride, and 30% by weight of glass fiber (Fuji Fiberglass, FES-1205) with a length of 3 mm.
The blended composition was kneaded at 270°C using a twin-screw extruder (TEX-30, Japan Steel Works) and pelletized.

[0025] Next, each test piece was molded in a mold at 80°C and evaluated. As can be seen from Table 1, the moldability and physical properties were very good.

Example 2 The composition of Example 1 was changed to PET/PBT=80/20 (weight ratio) and kneaded in the same manner as in Example 1 except that 8 parts of dimethoxypolyethylene glycol having an average molecular weight of 600 was added as a crystallization promoter. , molded. The moldability and physical properties were very good.

Comparative Examples 1 and 2 The composition of Example 2 with 0.5 parts of dimethoxypolyethylene glycol and 20 parts of dimethoxypolyethylene glycol and 2.5 parts of polyethylene glycol diglycidyl ether were kneaded and molded, respectively. did. In the former case, the appearance of the molded product was poor, and in the latter case, the physical properties were significantly deteriorated.

Comparative Examples 3 and 4 The compositions of Example 2 with 0.5 parts of maleic anhydride modified pp and 16 parts of maleic anhydride modified pp were kneaded and molded. In the former case, the appearance of the molded product was poor, and in the latter case, the physical properties were significantly deteriorated.

Examples 3 and 4 The composition of Example 2 was used, but dimethoxy polypropylene glycol and dimethoxy polytetramethylene glycol having an average molecular weight of 600 were used in place of dimethoxy PEG, and kneaded and molded. The moldability and physical properties were very good.

Examples 5 and 6 The composition of Example 2 was used, but polypropylene glycol diglycidyl ether and polytetramethylene glycol diglycidyl ether having an average molecular weight of 600 were used in place of polyethylene glycol diglycidyl ether, and kneaded and molded. Both had good moldability and physical properties.

Example 7 The composition of Example 2 was mixed and molded using 15% glass fiber and 15% mica instead of 30% glass fiber. Both moldability and physical properties were good.

Comparative Examples 5 and 6 The composition of Example 2, but with 0.05 part of maleic anhydride. pp,
Using modified pp modified at 6 parts/pp, it was kneaded and molded. In the former case, the appearance of the molded product was poor, and in the latter case, it was discolored.

[0033]

[Table 1]

[0034]

Effect of the invention The polyester resin composition of the present invention has 1
It has a high crystallization rate even when molded in a low-temperature mold below 00℃, has excellent surface gloss, mechanical strength, and toughness, and has excellent dimensional and shape stability even at high temperatures, making it suitable as an engineering plastic material. It is.

Claims (2)

[Claims] Claim 1: (A) has an intrinsic viscosity of 0.4 or more;
50 to 95 parts by weight of polyethylene terephthalate containing 80 mol% or more of ethylene terephthalate repeating units;
(B) For 100 parts by weight of a polyester resin consisting of 5 to 50 parts by weight of polybutylene terephthalate having an intrinsic viscosity of 0.5 or more and containing 80 mol% or more of butylene terephthalate repeating units, (a) polyalkylene glycol or its derivative and/or chemical formula 2
1 to 20 parts by weight of an epoxy compound represented by [Formula 1] (where R1, R1' are hydrogen, alkyl group, phenyl group, R2 is an alkylene group having 2 to 4 carbon atoms, n=5 to
100) [Formula 2] (However, R is an alkylene group having 2 to 4 carbon atoms, m = 1 to 1
00) (b) 0.1 part by weight of maleic anhydride in 100 parts by weight of polypropylene resin containing 80 mol% or more of propylene component
A polyester resin composition comprising 1 to 15 parts by weight of a maleic anhydride-modified polypropylene resin obtained by copolymerizing 5 parts by weight. 2. A polyester resin composition according to claim 1, wherein the polyester resin composition contains glass fiber and/or an inorganic filler.