JP2575039B2 - Glass fiber reinforced polyester resin composition - Google Patents

Description

The present invention relates to a novel glass fiber reinforced polyester resin composition. More specifically, the present invention is particularly suitable as a material for heat appliances, electric and electronic fields, and has excellent mechanical strength, rigidity, heat resistance, and the like, and has a good appearance, as well as small warpage and deformation. Further, the present invention relates to a glass fiber reinforced polyester resin composition capable of providing a molded article having improved weld strength.

[Prior art] Conventionally, thermoplastic polyester resins such as polyethylene terephthalate have been widely used as materials for various molded articles and films because of their excellent mechanical properties, electrical properties, thermal properties, and chemical resistance. Used. When such a polyester resin is used as a molding material, it is well known that glass fibers are added to the polyester resin for the purpose of further improving the strength, rigidity, heat resistance and the like of the molded product.

However, a molded article made of a polyester resin composition containing glass fibers has a problem that warpage and deformation are large due to the anisotropy of the glass fibers. Therefore, in order to solve this problem, it has been attempted to mix a small anisotropic plate-like mica, in this case,
There is a problem that the weld strength of the molded product is significantly reduced.

On the other hand, there has been proposed a composition in which an inorganic nucleating agent such as glass fiber, wollastonite and talc is blended with a polyester resin (Japanese Patent Application Laid-Open No. 58-206663). However, this composition has a disadvantage that a molded article having a good appearance cannot be obtained because the nuclear inorganic nucleating agent is inferior in its effect as a nucleating agent.

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of such a conventional polyester resin composition containing glass fibers, and is excellent in mechanical strength, rigidity, heat resistance and the like, and has good appearance. In addition, the present invention has been made to provide a glass fiber reinforced polyester resin composition capable of providing a molded article having a small warp and deformation and improved weld strength.

[Means for Solving the Problems] The present inventors have conducted intensive studies to develop a glass fiber reinforced polyester resin composition having the above-mentioned preferable properties. Wollastonite having an aspect ratio and a metal salt of an ionic hydrocarbon copolymer, each of which is blended at a predetermined ratio, have been found to be suitable for the purpose, and the present invention is completed based on this finding. Reached.

That is, the present invention relates to (A) 100 parts by weight of a polyester resin, (B) 10 to 120 parts by weight of glass fibers,
(C) 10 to 100 parts by weight of wollastonite having an aspect ratio of 5 to 50 and (D) metal salt 1 of an ionic hydrocarbon copolymer
An object of the present invention is to provide a glass fiber reinforced polyester resin composition containing 10 parts by weight.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the polyester resin used as the component (A) includes a linear polyester obtained by polycondensation of a bifunctional carboxylic acid component and an alkylene glycol component, and a bifunctional carboxylic acid component and an alkylene glycol component. As a main component, and a copolymerized polyester obtained by copolymerizing a third component capable of copolymerizing the same, and a mixture of the polyester and the linear polyester.

Examples of the difunctional carboxylic acid component include terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. Of these, terephthalic acid is preferred, and other dicarboxylic acids are preferred as long as the effects of the present invention are not impaired. Functional carboxylic acids such as oxalic acid, malonic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, and other aliphatic dicarboxylic acids and ester-forming derivatives thereof can be used in combination. The mixing ratio of these other dicarboxylic acid components is generally 20 to all dicarboxylic acids.
It is desirable to be within mol%.

The alkylene glycol component is not particularly limited, but specifically, ethylene glycol, propylene-
1,2-glycol, propylene-1,3-glycol, butylene-1,4-glycol, butylene-2,3-glycol,
Hexane-1,6-diol, octane-1,8-diol,
Aliphatic diols having 2 to 15 carbon atoms, such as neopentyl glycol and decane-1,10-diol, can be used. Of these diols, ethylene glycol and butylene glycol are preferred.

Further, as the third component, for example, acid components such as isophthalic acid, naphthalene-2,6-dicarboxylic acid, adipic acid, diphenylether-4,4'-dicarboxylic acid, sebacic acid, propylene glycol, neopentyl glycol, Glycols such as diethylene glycol, cyclohexanedimethanol, and 2,2-bis (4-hydroxyphenyl) propane, and oxyacids such as p-oxybenzoic acid and p-hydroxyethoxybenzoic acid.

In the composition of the present invention, among the polyester resins, in particular, in a phenol / tetrachloroethane mixed solvent (weight ratio 1/1), the intrinsic viscosity measured at a temperature of 30 ° C. is 0.4 dl / g or more, preferably 0.45 g / g or more. Polyethylene terephthalate and polybutylene terephthalate in the range of .about.1.5 dl / g are preferred.

In the composition of the present invention, as the glass fiber used as the component (B), any of alkali-containing glass, low alkali glass, and dream alkali glass can be used, and the length in the composition is preferably 0.02 ~ 2m
m, more preferably those in the range of 0.05 to 1 mm. Since this glass fiber may be broken during kneading with the polyester resin, the size of the glass fiber used for kneading is generally 0.1 to 6 mm in length.
And the diameter is usually 1
2020 μm is sufficient. The form of the glass fiber is not particularly limited, and any form such as roving, milled fiber, and chopped strand can be used.

Further, as the glass fiber, for the purpose of improving the adhesiveness with the polyester resin, it is desirable to use a glass fiber that has been subjected to a surface treatment such as a silane treatment, a borane treatment, or a chromium treatment, and then bound with an epoxy resin.

In the composition of the present invention, the glass fiber of the component (B) must be blended in a proportion of 10 to 120 parts by weight, preferably 15 to 100 parts by weight, based on 100 parts by weight of the polyester resin of the component (A). is there. If the amount is less than 10 weight, sufficient mechanical strength, rigidity and heat resistance cannot be obtained.
If it exceeds parts by weight, mechanical strength, rigidity,
Improvement in heat resistance and the like cannot be expected, but rather, the fluidity and appearance of the molded article tend to deteriorate.

In the composition of the present invention, wollastonite used as the component (C) is a natural white mineral (calcium metasilicate) having acicular crystals, represented by the chemical formula CaSiO ₃ , and usually 50% by weight of SiO ₂ and CaO 47. Wt%, other Fe ₂ O ₃ , Al
Contains ₂ O ₃ etc., specific gravity is about 2.9, bulk specific gravity is 0.8
~ 1.3.

In the composition of the present invention, the wollastonite needs to have an aspect ratio L / D in the range of 5 to 50, preferably 10 to 40. If this aspect ratio is less than 5,
The effect of reducing warpage and deformation is not sufficient, and if it exceeds 50, the appearance of molded articles tends to deteriorate.

The wollastonite of the component (C) must be blended in an amount of 10 to 100 parts by weight, preferably 20 to 80 parts by weight, based on 100 parts by weight of the polyester resin of the component (A). If the amount is less than 10 parts by weight, the effect of reducing warpage and deformation and the effect of improving weld strength are not sufficient. If the amount exceeds 100 parts by weight, although warpage and deformation are reduced, mechanical strength tends to decrease.

In the composition of the present invention, a metal salt of an ionic hydrocarbon copolymer is blended as the component (D). There is no particular limitation on the ionic hydrocarbon copolymer, for example, olefins such as ethylene, propylene, butylene, styrene, α-methylstyrene, and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic acid, and maleic anhydride. A copolymer with an unsaturated carboxylic anhydride such as an acid can be used. The metal ion species constituting the metal salts of these ionic hydrocarbon copolymers include, for example, alkali metal ions such as sodium ion and potassium ion, and alkaline earth metal ions such as magnesium ion, calcium ion and barium ion. And various types such as aluminum ion and zinc ion.

As the metal salt of the ionic hydrocarbon copolymer, those having a melt index (MI) of 50 g / 10 minutes or less are usually used. Preferred examples of the metal salt of the ionic hydrocarbon copolymer include a sodium salt and a potassium salt of a copolymer of ethylene and acrylic acid or methacrylic acid having MI of 0.5 to 10 g / 10 minutes.

In the composition of the present invention, the metal salt of the ionic hydrocarbon polymer (D) is used in an amount of 1 to 10 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the polyester resin (A).
It is necessary to mix at a ratio of 8 parts by weight. When the amount is less than 1 part by weight, the effect of the polyester as a crystallization accelerator is not sufficiently exhibited. When the amount exceeds 10 parts by weight, the effect of promoting crystallization is not improved for the amount. The mechanical strength and heat resistance may be reduced, and the fluidity may be deteriorated.

In the composition of the present invention, if desired, a crystallization accelerator, a fluidity modifier, a wax or the like as a release agent may be added, and further, an antioxidant, an ultraviolet absorber, a flame retardant, Various additives such as impact modifiers and colorants may be added. As the antioxidant, it is preferable to use a phenolic antioxidant and a phosphorus antioxidant in combination in order to improve both the stability of the molded product and the stability during processing.

There is no particular limitation on the method for preparing the composition of the present invention,
Any method can be used. For example, a method in which a polyester resin and various additional components are mixed in advance, and compounded by an extruder, etc., the polyester resin and each component other than glass fiber are mixed and put into an extruder, and the melt is mixed with glass fiber. A method of coating the periphery, cooling and then cutting to an appropriate length, a method of adding a glass fiber and / or an inorganic filler at or after the polymerization step of the polyester resin, and then mixing this with other additional components. For example, a method of blending a polyester resin containing a glass fiber with a polyester resin containing another additive component can be used.

[Effect of the Invention] The glass fiber reinforced polyester resin composition of the present invention comprises:
It is excellent in mechanical strength, rigidity, heat resistance, etc., has good appearance, has less warpage and deformation, and can give molded products with improved weld strength.
It is suitably used as a material for various molded articles in the electronic field and the like.

[Examples] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 to 11 Preliminarily dried (140 ° C., 5 hours or more) intrinsic viscosity 0.60 dl /
g polyethylene terephthalate resin (PET), length 3m
m, glass chopped strand (GF) with a diameter of 10 μm,
After premixing wollastonite (or gold mica) of various aspect ratios and sodium salt of ethylene-methacrylic acid copolymer (ethylene ionomer; nucleating agent),
The mixture was melt-kneaded at a cylinder temperature of 270 ° C. using a 57 mmφ vent-type twin-screw extruder and pelletized.

After pre-drying the obtained pellets (140 ° C., 5 hours or more), using an injection molding machine, cylinder temperature 270 ° C.
At a total mold temperature of 120 ° C, a disk for warpage measurement and weld (with or without)
A dumbbell-shaped test piece for tensile strength measurement and a test piece for appearance evaluation were prepared, and the warpage rate, tensile strength at break (with and without weld), their retention and appearance were evaluated. Table 1 shows the results. In the table, poor moldability refers to poor moldability and defects such as burr generation and mold wear.

 Each physical property was determined as follows.

(1) Warpage ratio A disk having a diameter of 150 mm and an inner thickness of 2 mm was allowed to stand still, and the heights of the two most warped points were A and B, and the warpage ratio was determined by the following equation.

(2) Tensile rupture strength was determined according to ASTM D 638.

(3) Retention The retention was determined according to the following equation.

Claims (1)

(57) [Claims] 1. (A) 100 to 100 parts by weight of a polyester resin, (B) 10 to 120 parts by weight of glass fiber, (C) 10 to 100 parts by weight of wollastonite having an aspect ratio of 5 to 50, and (D)
A glass fiber reinforced polyester resin composition containing 1 to 10 parts by weight of a metal salt of an ionic hydrocarbon copolymer.