JPH0753855A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the resin composition easily moldable even for the thin-wall molded products therefrom, rich in fluidity, capable of providing high-toughness, highly crystalline molded products. CONSTITUTION:The composition can be obtained by incorporating (I) 100 pts.wt. of a resin component composed of (A) 60-95wt.% of a thermoplastic polyester resin 0.6-0.9 in intrinsic viscosity [eta] and (B) 5-40wt.% of a thermoplastic polyester elastomer with (C) 0.5-45 pts.wt. of powdery talc 0.01-10mum in mean particle diameter and (D) 0-80 pts.wt. of a fibrous reinforcing agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition used as a molding material for various heat appliances, electric / electronic machine parts, automobile parts, etc. More specifically, it has high toughness and high toughness that facilitates thin-wall molding. And it relates to a highly crystalline polyester resin composition.

[0002]

2. Description of the Related Art Fiber-reinforced polybutylene terephthalate resin has excellent electrical properties, heat resistance, flame retardancy and chemical resistance, and is a resin for molding materials such as various heat appliances, electric / electronic machine parts and automobile parts. Widely used as.

Recently, electronic parts and the like have become thinner due to the tendency toward lightness, thinness, shortness, and size reduction. In the conventional fiber-reinforced polybutylene terephthalate resin, the thin part is not sufficiently filled with the resin, and there are cases where a satisfactory molded product corresponding to the thinning cannot be obtained. Measures have been taken to reduce the molecular weight of and improve fluidity. However, if the molecular weight of the polymer is simply lowered, the strength of the molded article is lowered, and a problem in terms of strength comes out.

Further, as a means for improving strength and not lowering fluidity, a method of adding a specific ester compound proposed in JP-A-3-263456 and JP-A-4-41548 are proposed. A method of blending an ABS resin and a method of adding a polyester-polyether block copolymer to polybutylene terephthalate to improve impact resistance have been proposed.

[0005]

However, these methods have the main purpose of improving the strength and do not concomitantly reduce the fluidity. Therefore, it is attempted to positively improve the fluidity. Not something to do. As described above, it is obvious that impact strength and toughness are reduced when the fluidity is positively improved due to the problem of moldability.

Therefore, an object of the present invention is to improve fluidity in order to obtain easy moldability even for a thin molded product, and
An object of the present invention is to provide a polyester resin composition capable of achieving high cycle molding without lowering toughness.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the problems of the prior art, the present inventor has found that polybutylene terephthalate having a specific molecular weight has a thermoplastic polyester elastomer and a specific particle size. It was found that by mixing the talc and the fibrous reinforcing material, it is possible to obtain a molded product with excellent fluidity, toughness and high cycle property.
The present invention has been reached.

The present invention provides (A) an intrinsic viscosity [η] of 0.6 to
0.9-90% thermoplastic polyester resin,
(B) 100 parts by weight of a resin component consisting of 5 to 40% by weight of a thermoplastic polyester elastomer, (C) 0.5 to 45 parts by weight of powdery talc having an average particle diameter of 0.01 to 10 μm, and (D) fibers. A polyester resin composition comprising 0 to 80 parts by weight of a reinforcing material.

The present invention will be described in detail below. The thermoplastic polyester resin (A) used in the present invention is an aromatic polyester having an aromatic hydrocarbon in a polymer chain unit, and an acid having an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component. It is a polymer or copolymer obtained by a condensation reaction from the component and the diol component.

The aromatic dicarboxylic acid or its ester-forming derivative used as the acid component is terephthalic acid, isophthalic acid, phthalic acid, naphthalene 1,4- or 2,6-dicarboxylic acid, bis (p-carboxyphenyl). Examples thereof include methane, anthracene dicarboxylic acid, 4,4′-diphenylcarboxylic acid, 4,4-diphenyl ether dicarboxylic acid and the like, and ester-forming derivatives thereof such as dialkyl ester and diallyl ester. Further, as the acid component, an aliphatic dicarboxylic acid such as a fatty acid such as glutaric acid, adipic acid, sebacic acid, oxalic acid or succinic acid, or an ester-forming derivative thereof can also be used.

As the diol component, ethylene glycol, propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,5-pentanediol,
1,6-hexanediol, decamethylene glycol,
Examples thereof include cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol and the like.

In the present invention, the thermoplastic polyester resin (A) preferably used is polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyhexamethylene terephthalate, polycyclohexane dimethylene terephthalate,
Examples thereof include polyethylene-2,6-naphthalate.
These can be used alone or in combination of two or more. Above all, the use of polyethylene terephthalate, polybutylene terephthalate or a copolymer mainly composed of these is preferable in terms of having mechanical strength.

Such a thermoplastic polyester resin (A) is contained in the resin component of the resin composition of the present invention in an amount of 60 to 95.
It is contained in the range of 70% by weight, preferably 70 to 95% by weight
Is. If the thermoplastic polyester resin is less than 60% by weight, the heat resistance is impaired, and conversely if it exceeds 95% by weight, the impact resistance is lowered. The thermoplastic polyester resin (A) has an intrinsic viscosity [η] of 0.6 to 0.9, and preferably an intrinsic viscosity [η] of 0.65 to 0.85. This is because if the intrinsic viscosity [η] is less than 0.6, the mechanical strength decreases, and if it exceeds 0.9, the fluidity decreases.

Next, the thermoplastic polyester elastomer (B) used in the present invention is a polyester-polyether block copolymer, and the number average of repeating units is 80 mol% or more composed of alkylene terephthalate units. A block copolymer having a hard segment of polyester having a molecular weight of 1,000 to 60,000 and a soft segment of poly (alkylene oxide) glycol having a number average molecular weight of 400 to 6000, in which 80 mol% or more of repeating units are composed of alkylene oxide units. . The poly (alkylene oxide) glycol component is preferably contained in the block copolymer in the range of 1 to 85% by weight, and more preferably in the range of 5 to 50% by weight.

The polyester constituting the hard segment contains terephthalic acid as a main acid component and has 2 to 10 carbon atoms.
Is a polymer having an aliphatic glycol as a main diol component, or a dicarboxylic acid or glycol other than the above in any combination and is copolymerized in a range of 20 mol% or less.

Examples of the poly (alkylene oxide) glycol constituting the soft segment include single polyglycols such as poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, and ethylene oxide. Random or block copolymerized polyglycols such as a copolymer of propylene oxide and propylene oxide, polyglycols copolymerized with other copolymerization components in an amount of 20 mol% or less, and the like, and these may be used alone or in a mixture. Can be used. Further, the poly (alkylene oxide) glycol has a number average molecular weight of 400 to 6
The range of 000 is preferable.

Specific examples of the polyester-polyether block copolymer used in the present invention include polyethylene terephthalate-polyethylene oxide block copolymer, polyethylene terephthalate-polytetramethylene oxide block copolymer, and polytetramethylene terephthalate. -Polyethylene oxide block copolymer, polytetramethylene terephthalate-polytetramethylene oxide block copolymer and the like can be mentioned.

In the present invention, modifiers such as oligostyrene, oligo-α-methylstyrene and oligovinyltoluene are added to these polyester-polyether block copolymers in an amount of 10% by weight or less. May be.

Such a thermoplastic polyester elastomer is contained in the resin composition of the present invention in an amount of 5 to 40% by weight, preferably 5 to 30% by weight. This is 5% by weight of thermoplastic polyester elastomer
If it is less than 40% by weight, the toughness is poor, and if it exceeds 40% by weight, the heat resistance is lowered.

Next, talc (C) used in the present invention
Has an effect as a crystal nucleating agent for the polyester resin (A), and those having an average particle diameter in the range of 0.01 to 10 μm are used. Average particle size 0.01μ
If it is less than m, the dispersibility of talc becomes worse, and conversely 10 μm
If it exceeds, the mechanical strength of the molded product from the resin composition will decrease. The average particle size of talc is preferably 0.
It is in the range of 5 to 8 μm. The average particle size is a value measured by a laser diffraction type particle size distribution measuring device.

The talc used is, for example, Mg ₃
Examples thereof include those having a chemical composition of (Si ₄ O ₁₀ ) (OH) ₂ and having a leaf shape or a flat shape. Such talc can be used alone or in a mixture,
The blending amount is 0.5 to 45 parts by weight with respect to 100 parts by weight in the resin component composed of the components (A) and (B). If the blending amount is less than 0.5 parts by weight, the compounding effect as a crystal nucleating agent is not exerted, and conversely, if it exceeds 45 parts by weight, a molded product from the resin composition becomes brittle.

The type and mixing method of the fibrous reinforcing material (D) used in the present invention are not particularly limited, and examples thereof include glass fibers, inorganic fibers other than glass fibers, carbon fibers, Heat resistant organic fibers and the like can be mentioned. Specifically, the fiber diameter is 1 to 20 μm, and the fiber length is 10 m.
m or less chopped strands of glass fiber or carbon fiber, glass fiber milled fiber, pitch-based carbon fiber,
Aromatic polyamide fibers, aromatic polyimide fibers, aromatic polyamideimide fibers, and combinations thereof can be used. Among them, chopped strands of glass fiber are particularly preferable.

The fibrous reinforcing material is used in the range of 0 to 80 parts by weight with respect to 100 parts by weight of the resin component composed of the components (A) and (B). This is because when the content of the fibrous reinforcing material exceeds 80 parts by weight, the flow processability decreases.

In the present invention, as long as the object of the invention is not impaired, inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide, halogen-based or phosphorus-based organic flame retardants, fillers such as metal powder and wood powder. , Antioxidant, UV absorber, lubricant, dispersant, coupling agent, foaming agent,
You may add additives, such as a crosslinking agent and a coloring agent, suitably.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. Examples 1 to 10 Intrinsic viscosity [η] 0.6 as thermoplastic polyester resin
5 to 0.85 polybutylene terephthalate (PBT)
A thermoplastic polyester elastomer (GP-300 manufactured by Toyobo Co., Ltd.), talc shown in Table 1 and chopped strand glass fibers having a fiber diameter of 13 μm and a fiber length of 3 mm at the ratios shown in Table 1. Blended, V
Mix evenly for 5 minutes in a mold blender. This mixture was extruded and pelletized at 250 ° C. using a 40 mmφ extruder with L / D = 25.

The obtained molded pellets were dried with hot air at 120 ° C. for 4 hours, and then with a 20 mmφ, 35 ounce screw in-line type injection molding machine, and a cylinder temperature of 250.
C., mold temperature 80.degree. C., injection molding at a molding cycle of 35 seconds, using the obtained test piece, tensile elongation according to ASTM D638, deflection temperature under load (HDT) according to ASTM D648, Width of 15m under the above molding conditions
A spiral having a thickness of m and a thickness of 2 mm was molded, and the spiral flow length was measured.

Regarding the high cycle property, after drying the molding pellets at 120 ° C. for 4 hours, immediately using a 3 ounce injection molding machine, the cylinder temperature was 250 ° C. and the mold 8 was used.
The box-shaped molded product shown in FIG. 1 was molded at 0 ° C., and the minimum moldable cooling time was measured. Here, the shortest cooling time refers to the shortest cooling time for which a molded product can be molded in a normal shape (a state in which the ejector pin does not swell or break through).

[0028]

[Table 1]

Comparative Examples 1 to 10 Table 2 shows polybutylene terephthalate (PBT) having the intrinsic viscosity shown in Table 2 as the thermoplastic polyester resin, and the thermoplastic polyester elastomer, talc and glass fiber used in the examples. The mixture was mixed in a ratio, and a test piece was obtained in the same manner as in the example. And it evaluated by the method similar to an Example. The results are shown in Table 2.

[0030]

[Table 2]

From the above results, it can be seen that the compositions obtained in the examples of the present invention are superior in fluidity, toughness and high cycle property to the comparative examples.

[0032]

The polyester resin composition of the present invention contains the specific thermoplastic polyester elastomer, the specific talc and, if necessary, the fibrous reinforcing material.
Molded products excellent in high fluidity, high toughness and high cycle property can be obtained, and can be used in a wide range of fields such as various heat appliances, electric / electromechanical parts and automobile parts.

[Brief description of drawings]

FIG. 1 is a perspective view of the shape of a molded product molded to measure high cycle properties.

[Explanation of symbols]

 The numerical values indicate the dimensions of the molded product. The unit is mm.

Claims (1)

[Claims] 1. A resin component comprising 100 parts by weight of (A) 60 to 95% by weight of a thermoplastic polyester resin having an intrinsic viscosity [η] of 0.6 to 0.9 and (B) 5 to 40% by weight of a thermoplastic polyester elastomer. Parts and (C) average particle size 0.01
A polyester resin composition comprising 0.5 to 45 parts by weight of powdered talc of 10 μm and 0 to 80 parts by weight of (D) fibrous reinforcing material.