JP2001072844A - Heat-resistant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant resin composition tat has excellent heat resistance and shock resistance and never emits environmental estrogens. SOLUTION: The objective heat-resistant resin composition having excellent heat resistance and shock resistance and emitting no environmental estrogens can be obtained by including polybutylene terephthalate, polyethylene terephthalate, polyethylene and talc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant resin composition mainly used for containers for microwave ovens and the like.

[0002]

2. Description of the Related Art Conventionally, as a resin material for heat-resistant containers for microwave ovens, tableware for business use, tableware for infants, etc., it has been known that it has high impact resistance.
Polycarbonate resins have been frequently used because of their excellent heat resistance.

[0003]

However, the above-mentioned polycarbonate resin is bisphenol A which is an environmental estrogen (so-called environmental hormone) as a decomposition product.
The generation of The environmental estrogens remain in the environment for a long time without being decomposed by living organisms, and when taken up by living organisms, accumulate in the body and cause a high concentration of the organism. Moreover, it has been revealed that bioaccumulation progresses through the food chain, which can cause serious symptoms to the human body, such as causing abnormal secretion of hormones and destroying the reproductive system. With the increasing awareness of environmental issues in recent years, the use of polycarbonate resins that can decompose and generate environmental estrogens in heat-resistant containers and tableware for microwave ovens has become an extremely serious social problem.
There has been an urgent need to develop a heat-resistant resin composition that can be substituted for this.

The present invention has been made in view of such circumstances, and has as its object to provide a heat-resistant resin composition which is excellent in heat resistance and impact resistance and does not generate environmental estrogens.

[0005]

Means for Solving the Problems To achieve the above object, the heat-resistant resin composition of the present invention is characterized in that it contains polybutylene terephthalate, polyethylene terephthalate, polyethylene and talc.

That is, the present inventors have conducted research to develop a heat-resistant resin composition which exhibits heat resistance and impact resistance which can be substituted for polycarbonate resin and which does not decompose and generate environmental estrogens. The idea was that high thermal strength properties could be obtained if polyethylene terephthalate was compatible. And as a result of further research, by adding polyethylene to polybutylene terephthalate and polyethylene terephthalate, we succeeded in making polybutylene terephthalate and polyethylene terephthalate compatible and crystallizing, and by further mixing talc It was concluded that a resin composition having properties comparable to that of a polycarbonate resin was obtained, and the present invention was reached.

In the heat-resistant resin composition of the present invention, when the blending ratio of polybutylene terephthalate and polyethylene terephthalate is 10 to 20 parts by weight of polyethylene terephthalate with respect to 10 parts by weight of polybutylene terephthalate. In addition, polybutylene terephthalate and polyethylene terephthalate can be sufficiently mixed and crystallized, and exhibit sufficient heat resistance.

In the heat-resistant resin composition of the present invention, when the content of polyethylene is 5% or more and 20% or less by weight, polybutylene terephthalate and polyethylene terephthalate are sufficiently compatible to be crystallized. And the strength does not decrease more than necessary.

In the heat-resistant resin composition of the present invention, when the content of talc is 10% or more and 50% or less by weight, sufficient heat resistance can be obtained, and the strength does not decrease more than necessary.

When the heat-resistant resin composition of the present invention is used in a container for a microwave oven, it is particularly effective and effective because it does not decompose and produce environmental estrogens and does not adversely affect the human body. It is.

[0011]

Next, embodiments of the present invention will be described in detail.

The heat-resistant resin composition of the present invention comprises polybutylene terephthalate, polyethylene terephthalate,
It contains polyethylene and talc.

The mixing ratio of the above polybutylene terephthalate and polyethylene terephthalate is preferably 10 to 20 parts by weight of polyethylene terephthalate to 10 parts by weight of polybutylene terephthalate. The lower limit of the mixing ratio is more preferably 13 parts by weight, and the upper limit is more preferably 17 parts by weight.
Parts by weight. The most preferable value of the mixing ratio is 15 parts by weight. When the mixing ratio is 10 parts by weight of polybutylene terephthalate and polyethylene terephthalate is less than 10 parts by weight, polybutylene terephthalate and polyethylene terephthalate are not sufficiently improved in heat resistance due to compatibility and crystallization, Conversely,
If the amount exceeds 20 parts by weight, sufficient heat resistance cannot be obtained in the same manner as described above.

The content of the above polyethylene is 5% by weight.
% Or more and 20% or less. The upper limit of the polyethylene content is more preferably 15%, and the lower limit is more preferably 7%. Also,
The most preferred value for the polyethylene content is 10%.
If the polyethylene content is less than 5%, polybutylene terephthalate and polyethylene terephthalate cannot be sufficiently compatible to be crystallized, so that sufficient heat resistance cannot be obtained. If the polyethylene content exceeds 20%, the strength decreases rather. It is because.

The content of the talc is preferably 10% or more and 50% or less by weight. The upper limit of the talc content is more preferably 45%, and the lower limit is more preferably 15%. Talc content is 50
If it exceeds 10%, the strength is rather reduced, and if it is less than 10%, sufficient heat resistance cannot be obtained.

The talc has an average particle size of 2 μm to 10 μm.
Those having a size of μm or less are preferred. The upper limit of the average particle size is more preferably 5 μm, and most preferably 3 μm.
μm. If the talc particle size exceeds 10 μm, the strength is reduced and the formability is also reduced. If the talc particle size is less than 2 μm, the cost increases.

The heat-resistant resin composition is obtained by mixing resin pellets of polybutylene terephthalate, polyethylene terephthalate, and polyethylene with talc powder at a predetermined mixing ratio, heating and melting, kneading, and then pelletizing. Can be.

The heat-resistant resin composition is molded into a desired shape by a desired molding method such as injection molding or extrusion molding, and is mainly used for microwave oven containers, heat-resistant tableware and the like. When used for such applications, environmental estrogen is not decomposed and generated, and does not adversely affect the human body, so that it is particularly effective and effective. The use of the heat-resistant resin composition of the present invention is not limited to microwave oven containers, heat-resistant tableware and the like,
Any member that requires a certain degree of heat resistance can be used for various applications.

As described above, according to the above-mentioned heat-resistant resin composition, environmental estrogen is not generated as a decomposition product, and sufficient heat resistance and impact resistance can be ensured.

Next, an embodiment will be described.

[0021]

Example 1 Each resin pellet and talc powder were mixed at the following mixing ratio, kneaded, and then pelletized to obtain a heat-resistant resin composition of the present invention. [Blending ratio] Polybutylene terephthalate: 20% by weight Polyethylene terephthalate: 30% by weight Talc: 40% by weight Polyethylene: 10% by weight

[0022]

Example 2 Each resin pellet and talc powder were mixed at the following mixing ratio, kneaded, and then pelletized to obtain a heat-resistant resin composition of the present invention. [Blending ratio] Polybutylene terephthalate: 28% by weight Polyethylene terephthalate: 42% by weight Talc: 20% by weight Polyethylene: 10% by weight

Using the pellets of the heat-resistant resin composition of each of the above examples, a molded product of a microwave oven container was obtained by injection molding. As a result of performing a heat resistance test on each of the above molded articles according to the Household Goods Quality Labeling Law / Synthetic resin processed product quality labeling regulations (Notification No. 220 of the Ministry of International Trade and Industry, 1979)
The heat-resistant temperature of the container of Example 1 was 260 ° C.
The heat-resistant temperature of the container was 200 ° C.

The container of Example 1 was subjected to a Piccat softening temperature test (JIS K 7206).
The Piccat softening temperature was 0 ° C or higher.

The container of Example 1 was subjected to a plastic flow test (JIS K 7210) (test temperature 230 ° C., test load 10 kgf). As a result, the melt flow rate was 8.5 g / 10 minutes.

With respect to the container of the first embodiment, the Food Sanitation Law, foods, additives and other standards (Notification No. 37 of the Ministry of Health and Welfare of 1959)
No. 0) and a synthetic resin device or packaging container containing polyethylene terephthalate as a main component (Ministry of Health and Welfare Notification No. 20 of 1982). As a result, the following test results were obtained.
Standards for additives, etc. (Notification No. 370 of the Ministry of Health and Welfare of 1959
No.). In addition, there was no decomposition and production of environmental estrogens. [Test results] Lead (ppm): 1 or less Cadmium (ppm): 1 or less Heavy metal: Not detected Antimony: Not detected Germanium: Not detected Evaporation residue; Water (ppm): 1 or less Same as above; 4% acetic acid ) (Ppm): 1 or less as above; 20% alcohol (ppm): 1 or less as above; n-heptane (ppm): 1.0 Potassium permanganate consumption (ppm): 0.2

As described above, according to the heat-resistant resin composition of the present invention, environmental estrogen is not generated as a decomposition product, and sufficient heat resistance and impact resistance can be ensured. Was.

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Claims (5)

[Claims] 1. A heat-resistant resin composition comprising polybutylene terephthalate, polyethylene terephthalate, polyethylene and talc. 2. The heat-resistant resin composition according to claim 1, wherein the mixing ratio of polybutylene terephthalate and polyethylene terephthalate is 10 to 20 parts by weight of polyethylene terephthalate per 10 parts by weight of polybutylene terephthalate. 3. The content of polyethylene is 5% by weight.
The heat-resistant resin composition according to claim 1, which is not less than 20%. 4. The heat-resistant resin composition according to claim 1, wherein the content of talc is from 10% to 50% by weight. 5. The heat-resistant resin composition according to claim 1, which is used for a microwave oven container.