JPH03244658A - High impact polyester resin composition - Google Patents

Abstract

PURPOSE:To improve falling wt. impact strength, heat resistance, and surface characteristics and reduce molded shrinkage by mixing a polyester, an ASA resin and/or AES resin, and a specific graft copolymer. CONSTITUTION:A graft copolymer is prepd. by graft copolymerizing 100-50 wt.% (meth)acrylic ester and 0-50 wt.% at least one monomer selected from the group consisting of styrenic compds. in the presence of a polymer having a glass transition point of 0 deg.C or lower and mainly comprising butadiene. Then, 1-95 wt.% polyester having an m.p. of 150-300 deg.C and an intrinsic viscosity of 0.5 or higher, 1-95 wt.% resin comprising an ASA resin (an alkyl acrylate- modified styrene-acrylonitrile copolymer) and/or AES resin (an ethylene- propylene rubber-modified styrene-acrylonitrile copolymer), and 0.5-98 wt.% said graft copolymer are melt-mixed at a temp. lower than 300 deg.C and 10 deg.C higher than the m.p. of the polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an impact-resistant polyester resin composition that provides a molded product with good impact resistance, heat resistance, and molded product appearance.

(Prior Art) Conventionally, in order to improve the toughness and rigidity of polyester, compositions in which SA resin or AES resin is blended with polyester have been disclosed, for example, in Japanese Patent Publication No. 1-15533 and Japanese Patent Publication No. 1-36857. It is more well known.

However, these &IItc products are simply a blend of the two, and although improvements in notched isot impact strength can be expected, there is currently little improvement in falling weight impact strength. .

(Issues to be solved by the invention!!) The present invention improves the falling weight impact strength of polyester, improves the tensile elongation, and provides injection molding with excellent surface properties, heat resistance, and low molding shrinkage. The challenge is to obtain goods.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention.

That is, the present invention uses polyester (a), ^SA#A resin and/or AES resin (b), and a polymer with a glass transition temperature lower than O''C as a backbone, and alkyl (meth)acrylates and styrenes. This is an impact-resistant polyester resin combination acid product characterized by containing a graft copolymer (c) to which at least a part of a polymer of one or more selected monomers is grafted.

The polyester that is component (a) in the present invention has a melting point of 150 to 300°C, for example,
Polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexane dimethylene terephthalate, polyoxyethoxybenzoate, polyethylene naphthalate, the above polyester components and other acid components and/or glycol components, such as isophthalic acid, P-oxybenzoic acid, Copolymerized acid components such as adipic acid, sebacic acid, geltaric acid, diphenylmethanedicarboxylic acid, and dimer acid, and glycol components such as hexamethylene glycol, diethylene glycol, neopentyl glycol, and bisphenol A1 neopentyl glycol alkylene oxide adduct. Examples include polyesters in a broad sense such as polyester, aromatic polyester/polyether block copolymers, aromatic polyester/polylactone block copolymers, and polyacrylates. In particular, polyesters with a melting point of 200°C or higher are preferable from the viewpoint of heat resistance.0 Normally, polyesters have a characteristic value determined by measurement at 30°C in a mixed solvent of phenol/tetrachloroethane (6/4 weight ratio) The viscosity is preferably 0.5 or more, and particularly preferably 0.6 or more.

Next, the 45A resin which is the component (b) in the present invention is:
It is a copolymer of styrene and acrylonitrile modified with alkyl acrylate, and the content of alkyl acrylate in the copolymer is 5 to 50% by weight. Also, the ratio of styrene and acrylonitrile is 90:10 by weight.
~65:35 is preferable, more preferably 82:18~13
:21 is desirable.

Outside this range, not only will the compatibility with the polyester be insufficient, but also the compatibility with the graft copolymer, which is component (c), will be insufficient, resulting in a decrease in impact resistance, especially falling weight impact strength. This is not desirable because

In addition to styrene, α-methylstyrene, vinyltoluene, etc. may be used as the copolymer component, and in addition to acrylonitrile, methacrylonitrile and the like may be used. The original alcohol group that constitutes the ester group of acrylate is 1
~6 carbon atoms, preferably 1 to 4 carbon atoms.

Next, the AES resin which is component (b) is a styrene and acrylonitrile copolymer modified with ethylene-propylene rubber, and the ethylene-propylene rubber accounts for 5 to 50% by weight in the copolymer. In addition, the ratio of styrene and acrylonitrile is 90:10 to 65:3 by weight.
5 is preferable, and 82:1B to 73:27 is more preferable. Outside this range, not only will the compatibility with the polyester be insufficient, but also the compatibility with the graft copolymer, which is component (c), will be insufficient. This is not preferable because it causes a decrease in impact resistance, especially falling weight impact strength.

In addition to styrene, α-methylstyrene, vinyltoluene, etc. may be used as the copolymer component, and in addition to acrylonitrile, methacrylonitrile and the like may be used.

As the ethylene/propylene rubber, a copolymer of ethylene and propylene having a weight ratio of 90:10 to 20:80, or a copolymer thereof with a small amount of non-conjugated diene is suitable. The non-conjugated diene may be any of norbornenes such as alunylnorbornene, cyclic dienes such as cyclopentadiene, and aliphatic dienes such as hexadiene.

Next, the graft copolymer (c) in the present invention has a polymer having a glass transition temperature lower than O''C as a backbone, and has an alkyl (meth)acrylate [(alkyl acrylate and/or alkyl methacrylate)] It refers to a graft copolymer in which at least a part of a polymer of one or more monomers selected from styrenes is grafted. The rubber component (referred to as a rubber component) is preferably mainly composed of butadiene, but it may also be a polymer obtained from monomers such as alkyl acrylates, such as butyl acrylate and ethyl acrylate, or a polymer mainly composed of polyethylene. Examples of the alkyl (meth)acrylates to be grafted include methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, etc. Copolymerization with alkyls may also be used, in which case the weight ratio of alkyl acrylates and alkyl methacrylates is O:1.
00-20: 80 is desirable.

In addition, the styrenes to be grafted as a c1 component other than those mentioned above have a weight ratio of alkyl (meth)acrylates and styrenes of 100:O in relation to compatibility with the (altc) component. ~50:50, preferably 100:
O~70: 30. Furthermore, too:o~90:1
0 is desirable.

Component (c) in the present invention is ASA, which is the component (d) above.
It is produced by the same manufacturing method as resin or AES resin, and by a method such as multi-stage emulsion polymerization, it becomes a shell-core copolymer structure. The content of the rubber component forming the core layer in component (c) is preferably 0 to 50% by weight, and the average particle size is 0.1 to 0.6 μm, particularly 0.1 to 0.4 μm. is preferred.

In the present invention, the blending amount of each component can be selected from a wide range depending on the various uses, and the (a) component and (b) component are each 1 to 95% by weight, and the (c) component is 0.5 to 98% by weight. %, especially component (c) is 5 to 3% relative to component (a).
0% by weight is preferred.

The composition of the present invention can be obtained by using conventional mixing equipment such as a roller kneader and a single or multi-screw extruder, especially a twin-screw extruder and a kneader. ) and (c) by melting and homogenizing them together, or by mixing components (b) and (c) into a melt of component (a). .

The manufacturing temperature of the composition of the present invention is preferably about 10°C higher than the melting point of the polyester as component (a), and 300°C or less, preferably 245 to 280°C.
a) When using a mixture of polybutylene terephthalate and polyethylene terephthalate as components, the polybutylene terephthalate content is high and the temperature is extremely high.
Polyethylene terephthalate-rich products are preferably produced at elevated temperatures.

The composition of the present invention may contain conventional additives, such as lubricants and mold release agents, nucleating agents, stabilizers, reinforcing agents, flame retardants, dyes and pigments, and particularly preferred reinforcing materials include glass fibers. , glass peas, mica, silicates, quartz, talc, titanium dioxide, silica, etc.

These additives can be blended in an amount of 5 to 50% by weight, particularly 10 to 40% by weight, based on the total composition.

In addition, in order to improve the flame retardancy of the composition of the present invention, it is sufficient to incorporate a nonflammable agent in an amount of 30% by weight or less based on the total composition.
Examples of flame retardants include polyhalogen diphenyl, polyhalogen diphenyl ether, polyhalogen phthalic acid and its derivatives, polyhalogenated polycarbonate, and polyhalogenated polystyrene, among which bromine-containing compounds are particularly effective. It is also preferred to contain customary synergists, such as antimony dioxide.

(Function) The composition of the present invention improves the compatibility of the graft copolymer, which is the component (c), with the ASA resin and/or AES resin, which is the (alt2 minute polyester) component. It is thought that this results in a uniformly dispersed state, and that the elongation and falling weight impact strength are dramatically improved.

(Example) The &1It2 product of the present invention will be specifically explained based on Examples, but the present invention is not limited thereto.

For the ASA resin (b) 1 minute of the present invention, Dialac A, S-300 manufactured by Mitsubishi Rayon Co., Ltd. was used, and for the ES resin, Uniplyte uB-600 manufactured by Sumitomo Noga Tank Co., Ltd. was used. In addition, the graft copolymer which is the component (c) is shown in Table 1.
The composition ratio shown in was used.

In addition, the Izod impact value in the examples and comparative examples is ^STM
-0256, and the tensile strength was measured according to STM D638. In addition, regarding the falling weight impact strength, D
It was measured based on the upont type falling weight impact test, and was expressed as the maximum absorbed energy in the area where the material does not break.

Table 1 Graft copolymer composition ratio Examples 1 to 7 Comparative examples 1 to 7 Polyethylene terephthalate with an intrinsic viscosity of 0.63 dl/H, polybutylene terephthalate with an intrinsic viscosity of 1.02 dl/g, ^SA or AES resin, and (c
) component (graft copolymer) is mixed in a blender in a predetermined amount, and then heated to a cylinder temperature of 2 using a 30 mm φ twin-screw extruder.
The mixture was cross-extruded at 65°C to form pellets.

After vacuum drying this pellet at 100°C for 5 hours,
It was made into a molded product using an injection molding machine. The mold temperature was 75°C. For comparison, a case in which component (c) was not used was similarly evaluated.

The results are shown in Table 2.3.

In table 1 P8 Polybutadiene PBu^ Polybutyl acrylate MM^ Methyl methacrylate St Styrene Margin below Table 2 Table 3 (Effect of the invention) The present invention and the parabolic elongation having the configuration described above.

It is possible to obtain a molded product that has excellent mechanical strength such as impact resistance, and has excellent surface properties without sink marks, warpage, etc. In particular, −
The falling weight impact strength at 40℃ has been significantly improved, and the dimensional stability against heat is excellent, resulting in a high degree of dimensional stability.
It can be widely used in injection molding and extrusion bottom shapes of parts that require high impact and high chemical resistance, such as materials subject to thermal stress, automobile parts, bumpers, and housings for office equipment, making it a great contribution to industry. It is.

Claims (1)

[Claims] Polyester (a), ASA resin and/or AES
Resin (b) and a polymer having a glass transition temperature lower than 0° C. are used as the backbone, and at least a portion of a polymer of an alkyl (meth)acrylate and one or more monomers selected from styrenes is grafted. Graft copolymer (c
) An impact-resistant polyester resin composition comprising: