JPH04353556A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain a molding material of polyester resin having excellent moldability, mechanical strength, appearance, luster, etc. CONSTITUTION:A molding material of polyester resin comprising (A) 100 pts.wt. polybutylene terephthalate, (B) 5-100 pts.wt. copolymerized polyethylene terephthalate having <=230 deg.C melting point and (C) 20-300 pts.wt. based on 100 pts.wt. polymer content (total of component A and B) of a filler (fibers, mica, etc.).

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to polyester resin compositions. More specifically, the present invention relates to a polyester resin composition that has excellent moldability, mechanical strength, and appearance (gloss), and is suitable for electrical, automobile, mechanical, and other uses.

0002

[Prior art] Polybutylene terephthalate has a fast crystallization rate, so it can be molded at an (excellent) high cycle.
It is known as a molding material with excellent mechanical strength, heat resistance, chemical resistance, electrical properties, and precision moldability. Furthermore, by incorporating a reinforcing filler, rigidity, heat distortion temperature, and creep resistance can be improved. However, when the amount of reinforcing filler added increases, the appearance (gloss) of the molded product deteriorates, resulting in a decrease in commercial value.

On the other hand, copolymerized polyethylene terephthalate with a melting point of 230°C or less has excellent transparency, heat resistance, and strength, and is used as a thermoformable sheet for packaging containers, but compared to polybutylene terephthalate, it has excellent transparency, heat resistance, and strength. Because of its slow crystallization rate, when used as an injection molding material, it has the drawbacks of a long molding cycle, a high-temperature mold, and poor mold release.

0004

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a polyester resin composition that has excellent moldability, mechanical strength, and appearance (gloss).

[0005]

[Means for Solving the Problems] The present inventors have discovered that by mixing polybutylene terephthalate and copolymerized polyethylene terephthalate with a melting point of 230° C. or less in a specific ratio, these drawbacks can be compensated for, and furthermore, it can be strengthened. They discovered that it is possible to improve the appearance of molded products filled with the material, and as a result of intensive research, they completed the present invention.

The present invention provides polybutylene terephthalate 10
0 parts by weight and 5 to 100 parts by weight of copolymerized polyethylene terephthalate with a melting point of 230° C. or lower, and 20 to 300 parts by weight of a reinforcing filler is blended with 100 parts by weight of a polyester resin, resulting in heat resistance, strength, and moldability. It is a polyester composition with excellent appearance (gloss).

The polybutylene terephthalate used in the present invention mainly consists of terephthalic acid and 1,4-butanediol components, and has an intrinsic viscosity ([η]) of 0.4 or more, preferably 0.5 or more, and more preferably 0. It is desirable that the polymer has a molecular weight of .6 or higher. When the intrinsic viscosity is less than 0.4, the strength decreases significantly and the material does not function satisfactorily as an industrial material. Here, the intrinsic viscosity is calculated from the results of measurement at a concentration of 1.2 g/100 ml in orthochlorophenol at 35°C.

The copolymerized polyethylene terephthalate used in the present invention is composed of a terephthalic acid component or an ethylene glycol component partially replaced with a copolymerized component, and has an intrinsic viscosity of 0.3 or more, preferably 0.4 or more, and Preferably it is 0.5 or more. Such copolymerization components include, for example, alkyl-substituted phthalic acids such as isophthalic acid, phthalic acid, methyl isophthalic acid, and methyl phthalic acid; naphthalene dicarboxylic acids such as 2,6-naphthalene dicarboxylic acid and 2,7-naphthalene dicarboxylic acid; 4-diphenyldicarboxylic acids, diphenyldicarboxylic acids such as 3,4-diphenyldicarboxylic acid, aromatic dicarboxylic acids such as phenoxyethanedicarboxylic acid such as 4,4-diphenoxyethanedicarboxylic acid; succinic acid, adipic acid, sebacic acid aliphatic dicarboxylic acids such as; aliphatic or alicyclic diols such as trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol; ε-oxycaproic acid, hydroxybenzoic acid, etc. Examples include oxycarboxylic acids such as, but are not limited to. One type or two or more types of these copolymerization components can be used, and the proportion thereof is 25 mol% based on the total dicarboxylic acids.
The content is more preferably 20 mol% or less.

[0009] The blending ratio of copolymerized polyethylene terephthalate in the present invention is 10 parts of polybutylene terephthalate.
The amount is in the range of 5 to 100 parts by weight, more preferably 10 to 50 parts by weight. If it is less than 5 parts by weight, no effect of improving the appearance will be observed, and if it exceeds 100 parts by weight, the heat resistance of the PBT resin will be impaired.

Examples of the reinforcing filler include fibrous reinforcing materials such as glass fiber, carbon fiber, calcium titanate fiber, and metal fiber, and plate-like reinforcing materials such as glass flakes, mica, and talc. In addition, these reinforcing fillers can be added as needed.
More than one type may be mixed. The blending ratio of these reinforcing fillers is 20 to 30 parts by weight per 100 parts by weight of the aforementioned polymer component.
0 parts by weight, preferably 25 to 150 parts by weight. If it is less than 20 parts by weight, a good appearance can be obtained without adding the copolymerized polyethylene terephthalate, and if it exceeds 300 parts by weight, it is difficult to cover the surface of the molded product with resin.
No appearance improvement effect is achieved.

[0011]Furthermore, a flame retardant or a flame retardant aid can be blended into the polyester composition of the present invention for the purpose of flame retardation, and in this case also the same effects as described above can be obtained. Flame retardants that can be used in the present invention include, for example, decabromo biphenyl ether, octabromo biphenyl ether, halogenated polycarbonate oligomers (for example, polycarbonate oligomers produced using brominated bisphenol A as a raw material), halogenated epoxy compounds, halogenated polystyrene, halogen Examples include halogen-containing compounds such as phenylene oxide polymers, phosphorus compounds such as red phosphorus and triphenyl phosphate, and phosphorus-nitrogen compounds such as phosphonic acid amide. Examples of flame retardant aids include antimony trioxide and sodium antimonate.

[0012] In addition, for the composition of the present invention,
Various additives (mold release agent,
A suitable amount of stabilizers, ultraviolet absorbers, colorants, etc.) can be added.

The method for producing the composition of the present invention is not particularly limited, but for example, polybutylene terephthalate chips, copolymerized polyethylene terephthalate chips, reinforcing fillers, flame retardants, etc. are mixed together. The mixture is then fed into the hopper of an extruder, melt-mixed in the extruder cylinder, and the extruded material is pelletized to form a molding material.

[0014] As a method for molding this composition, injection molding, extrusion molding, etc. are used. In the case of injection molding, the mold temperature is preferably 50 to 140°C, preferably 60 to 120°C. The thus obtained molded article of the polyester composition of the present invention has particularly excellent moldability, appearance, and strength.

Next, the present invention will be explained in more detail with reference to Examples. In addition, the blending ratio of the reinforcing filler is 1 part of the polymer component.
The value is based on 00 parts by weight.

[0016]

[Examples 1 to 3 and Comparative Examples 1 to 3] Intrinsic viscosity is 0.70
of polybutylene terephthalate and has an intrinsic viscosity of 0.64
Copolymerized polyethylene terephthalate A to C having a melting point of ~0.72 and 230°C or less were mixed in the proportions shown in Table 1, and commercially available chopped strand glass fiber with a single fiber length of 3 mm and commercially available mica (by weight) were mixed as a reinforcing filler. Ratio 1:1) was blended with 90 parts by weight per 100 parts by weight of the polymer, 20 parts by weight of brominated polycarbonate as a flame retardant, and 10 parts by weight of antimony trioxide as a flame retardant aid.
The mixture was melt-mixed using a mmφ extruder at a cylinder temperature of 270° C. to obtain molded chips.

[0017] This molded chip was molded using a screw in-line injection molding machine at a cylinder temperature of 270°C and a mold temperature of 80°C.
(cooling time: 10 seconds) to obtain a molded product. Table 1 shows the results of characteristic evaluation using this molded article.

In evaluating the molded product, the flexural modulus was evaluated using ASTM D-790, which was molded under the same conditions as described above. The glossiness of the molded product was obtained by measuring the 60° gloss of the surface of a 50 mmφ disc (thickness 3 mm) molded under the same conditions using a gloss meter.

[0019]

[Table 1] Copolymerized PET or homo-PET used A: Isophthalic acid 12 mol%, [η] = 0.64B:
Isophthalic acid 12 mol%, [η] = 0.70 C: Neopentyl glycol 13 mol%, [η] = 0.73 D: Isophthalic acid 8 mol%, [η] = 0.72 HomoP
ET η=0.71

From the results in Table 1, it can be said that the strength and appearance of the polyester resin composition of the present invention are excellent.

[0021]

[Examples 4-7 and Comparative Examples 4-5] Intrinsic viscosity is 0.70
Polybutylene terephthalate and copolymerized polyethylene terephthalate A having an intrinsic viscosity of 0.64 were mixed in the proportions shown in Table 2, and 20 parts by weight of commercially available chopped strand glass fibers with a single fiber length of 3 mm were added to 100 parts by weight of the polymer. Then, the mixture was melt-mixed using a 68 mmφ extruder at a cylinder temperature of 270° C. to obtain molded chips.

[0022] This molded chip was molded using a screw in-line injection molding machine at a cylinder temperature of 270°C and a mold temperature of 80°C.
(cooling time: 10 seconds) to obtain a molded product. Table 2 shows the results of characteristic evaluation using this molded article.

[0023]

[Table 2]

In evaluating the molded product, the flexural modulus was evaluated using ASTM D-790, which was molded under the same conditions as described above. The glossiness of the molded product was obtained by measuring the 60° gloss of the surface of a 50 mmφ disc (thickness 3 mm) molded under the same conditions using a gloss meter.

From the results in Table 2, the blending ratio of polybutylene terephthalate and copolymerized polyethylene terephthalate of the present invention is preferably in the range of 100 parts by weight to 5 to 100 parts by weight, particularly preferably 10 to 50 parts by weight. It can be said.

[0026]

[Examples 8 to 13 and Comparative Examples 6 to 9] The effects of the invention when the amount and type of reinforcing filler added are changed will be described below.

Polybutylene terephthalate with an intrinsic viscosity of 0.70 and copolymerized polyethylene terephthalate A with an intrinsic viscosity of 0.64 were mixed in the proportions shown in Table 3, and commercially available chopped strand glass fibers with a single fiber length of 3 mm or Glass flakes or mica were blended in the proportions shown in the same table, and then melted and mixed using a 68 mmφ extruder at a cylinder temperature of 270° C. to obtain molded chips.

[0028] This molded chip was molded using a screw in-line injection molding machine at a cylinder temperature of 270°C and a mold temperature of 80°C.
(cooling time: 10 seconds) to obtain a molded product. Table 3 shows the results of characteristic evaluation using this molded article.

[0029]

[Table 3]

[0030] The glossiness of the molded product is 5.
The 60° gloss on the surface of a 0 mmφ disk (thickness: 3 mm) was measured using a gloss meter.

From the results in Table 3, the blending ratio of the reinforcing filler is:
A suitable amount is 20 to 300 parts by weight, preferably 25 to 150 parts by weight, per 100 parts by weight of the polymer component.

Claims (2)

[Claims] Claim 1: (A) Polybutylene terephthalate 100
parts by weight, (B) 5 to 100 parts by weight of copolymerized polyethylene terephthalate with a melting point of 230°C or less, and 20 to 20 parts by weight of (C) filler per 100 parts by weight of the total amount of (A) and (B).
A polyester resin composition consisting of 300 parts by weight. 2. The polyester resin composition according to claim 1, wherein component (B) is a copolymerized polyethylene terephthalate consisting of isophthalic acid and ethylene glycol and/or terephthalic acid and neopentyl glycol.