JPS6248760A - Molding thermoplastic composition - Google Patents

Abstract

PURPOSE:A composition, obtained by incorporating a high-molecular weight polyester with an aromatic polycarbonate, ethylene/ethyl acrylate copolymer and filler, having improved impact resistance, dimensional stability, rigidity and moldability and suitable for automotive outside plates. CONSTITUTION:A composition obtained by incorporating (A) 35-85wt% high- molecular weight thermoplastic polyester with (B) 5-35wt% aromatic polycarbonate, (C) 5-85wt% copolymer of ethylene and ethyl acrylate and (D) 5-35wt% filler. Polyethylene terephthalate, etc., may be used as the component (A). Talc is preferred for the component (D).

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a thermoplastic resin composition for molding,
The present invention relates to a thermoplastic composition that has excellent impact resistance, dimensional stability, rigidity, and moldability, and is particularly suitable for automobile exterior panels.

(Prior Art) Polyester resin compositions are known as conventional thermoplastic compositions for molding, particularly thermoplastic compositions for large molded bodies such as automobile outer panels. Among polyesters, poly(ethylene terephthalate) has become an important component of injection moldable compositions due to the control of molecular weight, the use of nucleating agents, and the development of two-step molding processes. Furthermore, poly(II 4-butylene terephthalate) has an extremely high rate of crystallization from the melt, making it extremely useful as a component in molding compositions.

Furthermore, poly(1,4-butylene terephthalate) injection molded articles exhibit very good dimensional stability at temperatures close to or even significantly above their glass transition temperature. Poly(l,4-butylene terephthalate) is about 3
It can be injection molded at low temperatures, such as 0-60°C, resulting in short cycle times.

Great efforts have been made to improve their impact resistance. For example, printer T
nkmann) et al., U.S. Patent No. 3,591,659
It is disclosed in that specification that the modifier consists of polyalkyl acrylates, methacrylates and ethacrylates. Nakamura et al. U.S. Patent No. A, 864,428
In that specification, polyarylene carbonates and certain polybutadiene graft copolymers are proposed. Baron et al., U.S. Pat.
No. 4,07.9 discloses aromatic polycarbonates as impact modifiers. Schlichting et al., U.S. Pat.
No. 022,748 discloses that elastomeric graft copolymers having glass transition humidity below -20° C. are useful modifiers. Lane
), US Pat. No. 4,034,013 and Fornham et al., US Pat. No. 4,096,2.
No. 02 discloses that useful impact modifiers consist of multi-stage polymers having a rubbery first stage and a hard final stage, preferably containing units derived from alkyl acrylates. There is. For example, JP-A-58-45
In the No. 255 publication, the gist is to add 0.1 to 5% by weight of ethyl K/ethyl acrylate copolymer to improve the impact resistance of polybutylene terephthalate and ensure low specific gravity. Also, fibers such as glass fiber
It is said that the impact resistance is significantly increased by adding 604 eel, and that pigments, fillers, flame retardants, and stabilizers are also added. However, as described in the Examples, for example, these have a notched Izot test at room temperature of 1.2.
~1.4 ft, -1b/in (approximately 7.2~8.4
kg・Cm/C, +1), which is too insufficient for an automobile exterior panel. In addition, as described in the above-mentioned patent publication, when adding fibers such as glass fiber, 2.11 ft-1b/in (approx.
cm), but the surface roughness is extremely poor and cannot be used for the outer panels of side soles of automobiles.

Furthermore, JP-A-59-181646 describes the improvement of compatibility for improving weld line strength and the improvement of plate-out and mold releasability by adding linear low-density polyethylene to thermoplastic polyester. There is. Furthermore, this patent publication discloses that 6 to 70 parts by weight of aromatic polycarbonate may be contained in order to improve impact resistance, and approximately 2 to 70 parts by weight of core-shell type acrylic elastomer, acrylic copolymer, vinyl copolymer, etc. It is described that the content is 25 parts by weight. Furthermore, it is described that fillers, reinforcing agents, nucleating agents, fluidity promoters, colorants, flame retardants, stabilizers, etc. are added, and it is also stated that glass fiber, mica, etc. are particularly good as reinforcing agents. ing. However, as shown in the specific example, even though linear low-density polyethylene, which is the main component of the composition described in the above-mentioned patent publication, is useful for improving weld line strength, the addition of the linear low-density polyethylene reduces the impact resistance of the system as a whole. In addition, it significantly deteriorates physical properties in terms of rigidity, heat resistance, and dimensional stability.

(Problems to be solved by the invention) As described above, in the conventional impact resistance improved resin composition,
Because it was not intended for use in automobile exterior panels, it had low rigidity, such as a flexural modulus of 20,000 to 9/cm" or less, and poor dimensional stability, such as a linear expansion coefficient of IX.
10''cm/cm2, /'c or more, and there was a problem in that it could not be baked and painted at the same time as steel.

(Means for Solving the Problems) The present inventors have discovered that a thermoplastic polyester molding composition containing specific amounts of an aromatic polycarbonate, a copolymer of ethylene and ethyl acrylate, and a filler, particularly talc, has a high resistance to The present invention was accomplished by discovering that impact strength, rigidity, heat resistance, and dimensional stability can be significantly improved at the same time.

That is, the thermoplastic composition for molding of the present invention comprises (a) 35-851% high molecular weight thermoplastic polyester resin, ('b) 5-85% by weight aromatic polycarbonate, (c
) 5 to 35% by weight of a copolymer of ethylene and ethyl acrylate; (d) a filler, especially 5 to 35% by weight of talc;
This thermoplastic composition has significantly improved dimensional stability and moldability, and is useful in known general molding methods such as injection molding.

Polyesters suitable for use as component (a) in the composition of this invention include polyethylene terephthalate,
It may be selected from the group consisting of poly 1,4-butylene terephthalate and copolyesters. Copolyesters include copolyesters derived from one or more aliphatic and/or aromatic dicarboxylic acids and one or more aliphatic or cycloaliphatic glycols, such as random polyesters, block copolyesters. These may contain branched components,
The terminal groups may be controlled to increase compatibility with other components. Many grades are commercially available as materials that can be used, such as 1401-X manufactured by Toshisha Co., Ltd.
There is O7 (product name).

The blending amount of component (a) is in the range of 85 to 85% by weight, 85% by weight.
If the weight is less than 5%, the flexural modulus of the composition decreases;
If it exceeds % by weight, the flexural modulus decreases, or the dimensional stability or impact resistance deteriorates.

A variety of aromatic polycarbonates suitable for use as component (b) in the composition are known and commercially available. For example, it can be produced using dihydric phenol, as seen in US Pat. No. 2,993,835. It is also possible to use copolymers instead of these homopolymers.

The blending amount of component (b) is in the range of 5 to 85% by weight; if it is less than 5% by weight, the flexural modulus of the composition will decrease, and if it exceeds 35% by weight, the impact resistance will deteriorate.

Ethylene and ethyl acrylate copolymers suitable for use as component (c) in the composition are also known and readily available commercially.

The amount of component (c) is 5 to 35% by weight, preferably 25% by weight.
~85% by weight, and if it is less than 5% by weight, the impact resistance will deteriorate, and if it exceeds 85% by weight, the flexural modulus will decrease.

Inorganic fillers suitable for use as component (d) in the composition are preferably talc, but milled glass fibers, glass flakes, mica, and the like can also be used. Further effects may be obtained when these fillers are treated with a silane coupling agent such as aminosilane or a titanium coupling agent. component(
The blending amount of d) is 5 to 35 weights and 1 inch. If it is less than 5% by weight, the dimensional stability will be poor, and if it exceeds 35% by weight, the impact resistance will be poor.

In addition to containing the above-mentioned components (a) to (d) as essential components, the composition of the present invention contains stabilizers such as hindered phenolic antioxidants and phosphites, flow improvers, flame retardants,
It can contain an effective amount of at least one selected from the group consisting of nucleating agents.

The composition and proportions of the components of the composition of the present invention vary depending on the intended molded product, such as the required physical properties of the part, such as the outer panel of an automobile.

However, among various combinations, in the case of the proportions of the components specified in this invention, those specifically satisfying the required physical properties for large molded bodies such as automobile outer panels were obtained.

The composition of this invention can be manufactured by conventional methods. For example, one method is to simultaneously charge thermoplastic ff1tlE polyester, aromatic polycarbonate, ethylene-ethyl acrylate copolymer, and filler into a single-screw extruder to produce pellets for molding. As a result, the compatible thermoplastic polyester and aromatic polycarbonate are uniformly mixed, and the ethylene-ethyl acrylate copolymer and filler are uniformly dispersed in the IJ lux. Alternatively, these components can be mixed with powdered or granular thermoplastic polyester resin and then shaped directly, for example by injection molding techniques.

(Example) This invention will be explained by the following examples and comparative examples.

1 to 8, ~ poly(1,4-butylene terephthalate) (PBT),
Aromatic polycarbonate (PC), ethylene-ethyl acrylate (EEA) and filler were charged into a single screw extruder in the proportions shown in Table 1 along with conventional antioxidants and stabilizers, and heated at 265°C. It was kneaded and extruded. The extruded material was pelletized, molded at 265°C using an injection molding machine, and then cut out to prepare test pieces.The physical properties of the test pieces were measured using the methods shown below, and the results are shown in Table 1.

(a) Flexural modulus: Measured in accordance with ASTM D-79040.

(b) DuPont impact strength: A dart is dropped onto a molded plate and the energy required for fracture is determined according to the Meka method. (c) Izod impact strength: Measured according to ASTM D-256.

(Effects of the Invention) As explained above, the thermoplastic composition for molding of the present invention contains a high molecular weight thermoplastic polyester, an aromatic polycarbonate, a copolymer of ethylene and ethyl acrylate, and a filler in the specific proportions. By containing it, impact resistance, rigidity, heat resistance, and dimensional stability can be significantly improved at the same time, and the advantage is that it has a wide range of uses for various molded products such as automobile outer panels, especially large molded products. was gotten.

Claims (1)

[Claims] 1. (a) 35-85% by weight of high molecular weight thermoplastic polyester, (b) 5-35% by weight of aromatic polycarbonate, (c
A thermoplastic composition for molding, comprising: (d) 5 to 35% by weight of a copolymer of ethylene and ethyl acrylate; and (d) 5 to 35% by weight of a filler.