JPS60190451A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition capable of giving a molded article free from sinkmark and having excellent appearance even by molding using a high-temperature mold, by compounding a polyethylene terephthalate resin with glass fiber, a specific carboxylic acid metal salt, and a polycarbonate resin. CONSTITUTION:(A) 30-99pts.(wt.) of a polyethylene terephthalate resin is compounded with (B) 1-60% glass fiber, (C) 0.01-5% I a- or IIa-group metal salt of one or more organic carboxylic acids, and (D) 0.005-5% polycarbonate resin of formula (R1-R8 are H or halogen; R9 and R10 are alkyl; n is average recurring number and is >=3). The component c is preferably sodium stearate, sodium benzoate, etc., and the component D is preferably a resin wherein R9 and R10 in the formula is 1-5C alkyl.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to polyester resin compositions.

[Prior art]

Glass fiber-reinforced polyethylene tere-7 tallate resin has been steadily growing due to its excellent electrical properties, heat resistance, chemical resistance, and economic efficiency.

However, since polyethylene terephthalate resin has a slow crystallization rate, when molded at a mold temperature of 120° C. or lower, the appearance of the molded product is poor and sufficient heat resistance cannot be obtained.

Therefore, a method of molding using a high temperature mold of 120° C. or higher is usually used. However, when molded with a high-temperature mold, sink marks occur in the molded product. For this reason, molding is carried out by increasing the pressure holding time or increasing the injection pressure, but it is still impossible to avoid sink marks on thick parts and on the back side where bosses and ribs stand.

[Purpose of the invention]

An object of the present inventors is to provide a polyester resin composition that has an excellent appearance with few sink marks even when molded in a high-temperature mold.

[Structure of the invention]

(A) Polyethylene terephthalate resin 60-99
Heavy (B) Glass fiber 1-60% by weight (C) Low (also - other organic carboxylic acids of group Ⅰ a or group Ⅰ a of the periodic table metal salts 001-5 by weight - 〇)) At least one type of polycarbonate resin represented by the following formula CI) [1005 to 5% by weight (wherein R3-H is hydrogen, a halogen atom, or a hydrocarbon; R, to RIG are alkyl groups).

Further, n indicates the average number of repetitions and is 3 or more. ), and the total amount of each component of (c) to Φ) is 100
% by weight of a polyester resin composition.

The polyethylene terephthalate resin (A) used in the present invention refers to a homopolymer of linear polyethylene terephthalate having ethylene terephthalate as a constituent unit; a copolymer obtained by copolymerizing the unit component with other copolymerizable components; It refers to mixed resins of the above-mentioned homopolymers and copolymers, but is not particularly limited to these. Here, as other copolymerizable components, conventionally known acid components and glycol components can be used, and specifically, for example, phthalic acid, .r-sophthalic acid, adipic acid, sebacic acid, naphthazine-1 , 4- or 2.6-
Acid components such as dicarboxylic acid and diphenyl ether-4,4'-dicarboxylic acid; glycols such as propylene glycol, butylene glycol, neohentyl glycol, cyclohexane dimetatool, and 2,2'-bis(4-hydroxyphenyl)propane Ingredients: Oxy acids such as P-oxybenzoic acid, P-hydroxybenzoic acid, P-hydroxyethoxybenzoic acid, and the like.

As the polyethylene terephthalate resin (A), polymers obtained by either a method of polycondensation via transesterification or a method of polycondensation via direct esterification can be used. The viscosity [η] is desirably in the range of [1,4 to t4, and a polymer with a large [η] can be obtained by subjecting the polymer obtained by the above-mentioned ordinary polymerization method to a known solid phase polymerization method. Obtainable. Note that [η] is phenol/
Tetrachloroethane = 50150 (weight ratio) 25 in solvent
This value is calculated from the solution viscosity measured at °C.

The polyethylene terephthalate resin (A) used in the present invention is blended in a range of 30 to 99% by weight in the resin composition composed of each of the components (A) to 0). 3
If it is less than 0% by weight, the fluidity processability decreases, which is not preferable. Further, if the amount exceeds 99% by weight, the object of the present invention cannot be achieved.

゛Glass fiber (B) used in the present invention is (A)
~Φ) It is used in the range of 1 to 60% by weight in the resin composition composed of each component. If the blending amount of glass fiber exceeds 60% by weight, the molding processability seen from the fluidity processability will decrease, and if the blending amount is less than 1% by weight, the reinforcing effect of the glass fiber will be small, which is not preferable. The type of glass fibers used and the method of mixing them are not particularly limited, and both roving type and chopped strand type can be used, but from the viewpoint of productivity, chopped strand type is preferable. In addition, in consideration of workability during mixing, wear of the molding machine, and breakage during the molding process, it is particularly preferable that the fiber length of the glass fibers during mixing is about 0.4 to 6 ridges in the final molded product. It is sufficient if the length is about 0.2 to 21111. As the glass fiber, commercially available products that have been subjected to various treatments can be used as they are.

In addition, the gold and steel bases of specific organic carboxylic acids in the present invention (
C) is effective as a crystal nucleating agent for polyethylene terephthalate resin, and metal salts of organic carboxylic acids belonging to group 1 a or group δ of the periodic table are used. The organic carboxylic acid may be either aliphatic or aromatic. Specific examples of metal salts of organic carboxylic acids include sodium laurate, potassium laurate, sodium myristate, potassium myristate, sodium stearate, potassium stearate, sodium octacosanoate, potassium octacosane, calcium myristate, calcium stearate, sodium benzoate, potassium benzoate,
Examples include calcium benzoate, potassium terephthalate, sodium terephthalate, lithium terephthalate, etc.
Among these, sodium stearate, sodium benzoate, potassium benzoate, lithium terephthalate and the like are particularly preferred. These specific organic carboxylic acid metal salts can be used alone or in combination, and the amount of the metal salts added is 0.01 to 5% by weight in the resin composition composed of each component (4) to (D). If it is less than 0.01% by weight, excellent heat resistance and appearance improvement effects will hardly be exhibited. Moreover, if the weight ratio exceeds 5, the molded product becomes brittle, which is not preferable.

Furthermore, the polycarbonate resin constituting the polyester resin composition of the present invention is represented by the general formula [I], where R and % R are hydrogen or halogen atoms. Specific examples include chlorine, bromine, iodine atoms, etc. 0 or R.~R1G is an alkyl group, and the number of carbon atoms is not particularly limited, but those with 1 to 5 carbon atoms are particularly preferred. . In addition, n indicates the average number of repetitions, 5
The above is necessary. If n is less than 3, it is not preferable because the intended improvement in preventing sink marks is not achieved.

In the present invention, () of the polycarbonate resin represented by the general formula CI) can be used alone or in combination, but in the polyester resin composition composed of each component (g) to (D). , OO is required to be blended in a range of 5 to 5% by weight, and a blending amount of 0.005% by weight has almost no effect on improving the appearance of molded products, such as sink marks.

Moreover, a blending amount exceeding 5% by weight is not preferable because excessive foaming occurs and the appearance of the molded product becomes poor.

The addition method of polycarbonate resin Φ) is ←) ~ (C)
It may be a method of kneading together the five components at the same time, or a method of pellet blending with a polyester resin consisting of components (G) to (C). However, in the case of the method of kneading the polyester resin composition of the present invention in one batch, it is necessary to extrude at a cylinder temperature of 280°C or less in order to suppress foaming in the cylinder of the extruder. A specific example of adjustment is as follows.

Specific amounts of glass fiber (B), metal salt of organic carboxylic acid (C), and polycarbonate resin) are added to sufficiently dried polyethylene tere-7 tallate resin (A), and mixed appropriately using a tumbler or the like. After mixing in a container, the mixture is fed to an extruder or the like and subjected to melt cross-extrusion to form pellets.

The polyester resin composition of the present invention may contain various additives such as ultraviolet absorbers, antioxidants, stabilizers such as heat deterioration inhibitors, dyes and pigments, flame retardants, and quenching agents without departing from the purpose of the present invention. Can be blended.

The present invention will be specifically explained below using Examples.

Examples 1 to 22, Comparative Examples 1 to 4 Polyethylene terephthalate homopolymer with [η] of 0.72, various substances defined by the present invention as components (C) and (D), and 31III chopped strand glass Fibers (hereinafter abbreviated as GF) were blended in the proportions shown in Table 1 and uniformly mixed for 5 minutes in a V-type cleanser. This mixture was extruded using a 65φ vent type melt extruder at a cylinder temperature of 221°C to 280°C, and pelletized to obtain a resin composition of the present invention.

These resin compositions were molded using an 8-ounce screw injection molding machine at a cylinder temperature of 270°C and a mold temperature of 140°C.
A round bar molded product of 63φ×70fi was obtained in a molding cycle of 3 minutes.

The sink mark of this molded article was determined by the expansion ratio.

<Method for Measuring Expansion Ratio> The expansion ratio of the 53φ×70 tag round bars shown above molded under various conditions was measured by the method shown below. The higher the foaming ratio, the less sink marks will occur.

Here, the blank specific gravity refers to the specific gravity of a molded article to which components (C) and (D) are not added.

GF15% blank specific gravity 142 GF30% 1 153 GF50 Chi I 1.68

Claims (1)

[Scope of Claims] France) Polyethylene terephthalate resin 30-99% by weight) Glass fiber 1-60% by weight (C) At least one organic carboxyl group 1 a or group 2 a of the Periodic Table Metal salt 0.01-5% by weight (D) At least one type of polycarbonate resin represented by the following formula CI) 0005-5% by weight (wherein R1 to R8 are hydrogen or halogen atoms. R0
~RI0 is an alkyl group. Further, n indicates the average number of repetitions and is 3 or more. ), and (G) to (D
) A polyester resin composition in which the total amount of each component is 100% by weight.