JPH06240121A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition, improved in appearance (gloss) of moldings and excellent in mechanical strength and dimensional accuracy at the same time. CONSTITUTION:This resin composition is obtained by adding a platy and/or a fibrous filler to an aromatic polyester represented by polybutylene terephthalate (PBT) or polybutylene naphthalate (PBN) and then blending the resultant mixture with a polyester ether elastomer. The polyester ether elastomer herein is composed of a hard segment of an aromatic dicarboxylic acid component and an aliphatic dihydroxy compound and a soft segment of a polyether having 500-6000 molecular weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition having excellent mechanical strength and dimensional accuracy and having a good appearance (gloss).

[0002]

2. Description of the Related Art Aromatic polyesters are generally thermoplastic materials having various excellent properties such as oxidation resistance and solvent resistance.
It has mechanical properties and is suitable for obtaining fiber films or general moldings.

It has already been known that characteristics such as mechanical strength, rigidity and dimensional accuracy can be improved by adding a fibrous filler such as glass fiber or a plate-like filler such as mica to the aromatic polyester. There is. However, if the addition amount of these inorganic fillers is increased, the appearance (gloss) of the molded product is significantly reduced and the commercial value is also reduced.

[0004]

An object of the present invention is to solve the above problems and to provide a new resin composition having excellent mechanical strength and dimensional accuracy and having a good appearance (gloss).

[0005]

The present invention relates to (a) aromatic polyester 9
5 to 50 parts by weight and (b) 5 to 50% by weight of the plate-like and / or fibrous filler in total of 100 parts by weight, and (c) 2 to 40 parts by weight of a specific polyester-ether elastomer. It is a thermoplastic resin composition.

The present invention will be described in detail below.

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

Instead of such an aromatic dicarboxylic acid or an ester-forming derivative thereof, 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 an ester-forming derivative thereof is used. can do. Examples of the diol component include aliphatic glycols such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, and cyclo-hexanedimethanol, 1,
A diol having an aromatic ring such as 4-bisoxyethoxybenzene or bisphenol A, or an ester-forming derivative thereof can be applied. As the aromatic polyester, polybutylene terephthalate and polybutylene naphthalene dicarboxylate are particularly preferable.

Examples of the plate-like filler in the present invention include mica, glass flakes, various metal foils and the like. The weight average flake diameter of these plate-like fillers is 40 to 25.
It is preferably about 0 μm and has a weight average aspect ratio of 10 to 100 in view of characteristics such as dimensional accuracy of the molded product, but is not limited to this.

The fibrous filler used in the present invention includes glass fiber, carbon fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber,
Examples thereof include inorganic fibrous substances such as silicon nitride fibers, boron fibers, titanium potassium fibers, and metallic fibrous substances such as stainless steel, aluminum, titanium, copper, and brass. The fiber diameter of these fibrous fillers is preferably 5 to 20 μm, and the aspect ratio is preferably 5 or more, but is not limited thereto.

When the plate-like filler and the fibrous filler are used in combination, the ratio of each component can be selected according to the purpose. Therefore, if impact strength is required, the ratio of the fibrous filler can be increased, and if the dimensional accuracy is emphasized, the ratio of the plate-shaped filler can be increased. Further, the addition amount of the plate-like filler and / or the fibrous filler is
5 to 50 relative to 95 to 50 parts by weight of aromatic polyester
Parts by weight. If the addition amount is less than 5 parts by weight, properties such as strength and dimensional accuracy cannot be imparted. When the amount of filler exceeds 50 parts by weight,
It is not preferable because the extrudability is remarkably reduced.

The polyester elastomer (c) used in the present invention comprises a hard segment containing an aromatic dicarboxylic acid as an acid component and an aliphatic dihydroxy compound as a glycol component, and a soft segment composed of a polyether.

Examples of the aromatic dicarboxylic acid in the hard segment include naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylketonedicarboxylic acid and diphenylsulfonedicarboxylic acid. It The acid components in the hard segment do not have to be the same aromatic dicarboxylic acid, but it is preferable that 50 mol% or more of all the acid components are the same aromatic dicarboxylic acid.

Examples of the aliphatic dihydroxy compound in the hard segment include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol and hexamethylene glycol, and 50 mol% or more of all glycol components are the same. It is preferably an aliphatic dihydroxy compound.

The polyether constituting the soft segment means a polymer of the above-mentioned aliphatic glycol, specifically, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polypentamethylene glycol, polyhexamethylene glycol. Or the copolymer etc. of these are illustrated. The molecular weight of such polyether is preferably 500 to 6000, and 800 to 3
000 is particularly preferred.

The ratio of hard segment / soft segment can be changed according to the required characteristics, but is usually 10/90 to 90/10, preferably 20/8.
It is selected in the range of 0 to 80/20. The degree of polymerization of the polyester elastomer can be appropriately set, but it is usually preferable to select one having a reduced viscosity in the range of 1.0 to 2.5 as measured with an orthochlorophenol solution at 35 ° C.

As a method for producing the polyester elastomer, an ordinary method for producing a copolyester can be adopted. Generally, an aromatic dicarboxylic acid or its alkyl ester, an aliphatic dihydroxy compound and a polyether are charged into a reactor to carry out a linear esterification or transesterification reaction, and then a high vacuum is conducted until a desired degree of polymerization is obtained. A production method in which a condensation reaction is performed is adopted.

The polyester elastomer used in the present invention is added in an amount of 100 parts by weight of (a) 95 to 50 parts by weight of aromatic polyester and (b) 5 to 50% by weight of plate-like filler and / or fibrous filler. On the other hand, it is 2 to 40 parts by weight. If the amount added is less than 2 parts by weight, the effect of improving the appearance (gloss), which is the object of the present invention, will not be exhibited, and if it exceeds 40 parts by weight, the strength and rigidity of the composition will remarkably decrease, such being undesirable.

Various polymers and / or various additives may be contained in the resin composition of the present invention within a range not impairing the object of the present invention. Examples of the polymer include polyphenylene ether resin, polyamide resin, and polyphenylene sulfide resin. Also, as additives, flame retardants, flame retardant aids, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, ultraviolet absorbers,
Examples include release agents and coloring agents.

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

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples. The method of measuring each property evaluated in the examples is as follows.

(1) Tensile strength According to ASTM: D-638.

(2) Molding Shrinkage A flat plate having a thickness of 1.5 mm is injection-molded and the molding shrinkage is measured for evaluation. Molding shrinkage (%) = {[(mold size)-(mold size)] / (mold size)} x 100 (means shrinkage in the direction perpendicular to the resin flow) (3) Gloss 50 mm A disc having a diameter of 3 mm and a thickness of 3 mm is injection-molded, and 60 ° gloss of the disc surface is measured using a gloss meter.

The intrinsic viscosity of the aromatic polyester is 1.2 g of the polymer per 100 cm ³ of orthochlorophenol.
It is the value which melt | dissolved and was calculated at 35 degreeC with the Ostwald viscometer.

The aromatic polyester, polyester elastomer, plate-like filler (mica) and fibrous filler (glass fiber) used in the examples are as follows.

Polyester 1: Polybutylene terephthalate having an intrinsic viscosity of 0.70.

Polyester 2: Polybutylene naphthalene dicarboxylate having an intrinsic viscosity of 0.77.

Elastomer 1: 38 wt% of polybutylene terephthalate as the hard segment and 62 wt of polytetramethylene glycol as the soft segment.
% Polyester elastomer.

Elastomer 2: Polyester elastomer consisting of 40 wt% of polybutylene terephthalate and 5 wt% of polybutylene isophthalate as the hard segment and 55 wt% of polytetramethylene glycol as the soft segment.

Elastomer 3: 34 wt% of polybutylene naphthalene dicarboxylate as a hard segment
%, And 66 wt% of polytetramethylene glycol as a soft segment, a polyester elastomer.

Mica 1: Muscovite mica having an average particle size of about 100 μm.

Mica 2: Phlogopite type mica having an average particle size of about 200 μm.

Glass fiber: Chopped strand type glass fiber having a single fiber length of 3 mm.

[0034]

Examples 1 to 5 and Comparative Examples 1 to 5 The polyesters 1 and 2, the polyester elastomers 1 to 3, the mica 1 and 2 and the glass fibers were uniformly mixed in advance at a ratio shown in Table 1, and then a single fiber having a diameter of 68 mm was used. It was melt-kneaded with a shaft extruder to obtain pellets for molding. The obtained pellets were molded into a test piece for measuring physical properties with an injection molding machine. Polyester 1
The extrusion temperature and the cylinder temperature during molding are 26
The temperature was 5 ° C and the mold temperature was 80 ° C. The extrusion temperature of polyester 2 and the cylinder temperature during molding are 275.
C. and the mold temperature was 120.degree.

Table 1 shows the tensile strength, molding shrinkage and 60 ° gloss of the obtained test piece.

The addition of the polyester elastomer was found to improve the glossiness (appearance).

[0037]

[Table 1]

It was found that the tensile strength of the molded product was insufficient when the amount of the elastomer was too large (Comparative Example 4).

Claims (4)

[Claims] 1. (a) 95 to 50 parts by weight of an aromatic polyester and (b) a plate-like and / or fibrous filler 5
(C) to 100 parts by weight in total of 50% by weight.
A thermoplastic resin composition comprising 2 to 40 parts by weight of a polyester elastomer. However, the polyester elastomer has a hard segment containing an aromatic dicarboxylic acid as an acid component and an aliphatic dihydroxy compound as a glycol component, and a polyether as a soft segment. 2. The thermoplastic resin composition according to claim 1, wherein the plate-like filler (b) is mica and the fibrous filler is glass fiber. 3. The thermoplastic resin composition according to claim 1, wherein the aromatic polyester (a) is polybutylene terephthalate. 4. The thermoplastic resin composition according to claim 1, wherein the aromatic polyester (a) is polybutylene naphthalene dicarboxylate.