Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1995-02-15
1997-09-02
Mosley, Terressa
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
427 58, 427384, 4273855, 428421, 428480, 524601, 524789, 528176, 528190, 528193, C08G 6400
Patent
active
056632762
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an organic material of a novel wholly aromatic polyester which has a high elastic coefficient, fluidity and heat resistance. More particularly, the invention relates to an organic material as a polymer having a specific composition and it has a high elastic coefficient which is realize by orienting the chains of molecules in the direction of the flow of material in a fluidized condition.
Furthermore, the present invention relates to component parts of electronic heating devices and oven ware which are made from the wholly aromatic polyester and are excellent in mechanical strength, heat resistance, moldability, workability and anti-electronic oven-range characteristics.
The term electronic heating devices herein referred to includes, as described later, electronic ovens, electronic ranges and electronic oven-ranges.
The present invention further relates to articles which are made of a heat resistant wholly aromatic polyester and are coated with fluorocarbon resin such as polyfluoroethylene.
BACKGROUND ART
Some plastic materials such as polymethylterpene and polysulfone are used for making cooking ware which is used in microwave ovens or electronic oven-ranges and component parts of electronic oven-ranges.
The methods of heating in the electronic oven-ranges are exemplified by range heating with the irradiation of microwaves and oven heating with hot air blasting and grill heating with infrared lamps. The cooking ware used in electronic oven-ranges and several component parts of electronic oven-ranges are required to have various properties such as excellent heat resistance, chemical resistance and desirable external appearance. Especially, concerning the heat resistance, very severe characteristic property is required because the parts or cooking ware are exposed not only to the high-frequency heat but also to the heat of oven heating or grill heating. For example, the temperature in an electronic oven-ranges is generally about 260.degree. C. and, in the case of oven heating, the temperature becomes partially about 300.degree. C. and, in the case of grill heating, the temperature sometimes becomes above 300.degree. C. Accordingly, the articles used for this purpose must not be deformed and must have sufficient mechanical strength in practical uses.
The wholly aromatic polyester has excellent properties due to its structure. Especially, in view of the heat resistance, it is the best one among all sorts of resins. The wholly aromatic polyesters which are prepared from terephthalic acid, isophthalic acid, p-hydroxy benzoic acid or its derivatives, and biphenyl-4,4-diol (4,4-diphenol) or its derivatives are widely used for electric and electronic fields such as ovens and ranges because they can be shaped by injection molding, their mechanical and electrical properties are excellent and they can meet other various requirements in the use of plastic articles such as good heat resistance, chemical resistance, oil resistance, radiation resistance, and dimensional stability (e.g. Patent Publication No. Hei 4-20327).
The above-mentioned wholly aromatic polyesters are acceptable in the heat resistance as represented by heat distortion temperature. It is, however, pointed out as a defect that, when injection molded articles are put in an atmosphere of 300.degree. C. or above, oven-blistering (blistering caused by heat) is liable to occur in the surfaces of molded articles. When oven-blistering occurs in the surface of molded articles, the external appearance of them are spoiled resulting in the loss of their commercial value. The cause of this blistering is not always clear. Even in the case of highly heat resistant wholly aromatic polyester resin having a heat distortion temperature of above 350.degree. C., the blistering often occurs at temperatures below 300.degree. C. In other words, in the electronic oven-ranges having functions of oven heating and grill heating, when the wholly aromatic polyester is used as their constituent parts or as cooking ware, they are
REFERENCES:
patent: 5071942 (1991-12-01), Brewbaker et al.
Murouchi Satoshi
Watanabe Hideo
Yoneta Hiroyoshi
Mosley Terressa
Nippon Petrochemicals Company Limited
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