Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1996-07-24
1997-12-16
Teskin, Fred
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526133, 526160, 526340, 526346, 5263471, 5263472, 528499, 528501, C08F21204, C08F11204, C08F 1204
Patent
active
056986521
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a styrenic polymer and a molded article, and more specifically, it relates to a styrenic polymer having a syndiotactic configuration which is excellent in various characteristics such as breaking strength, impact resistance and heat resistance, and a molded article of this styrenic polymer.
BACKGROUND ART
It is already known that styrenic polymers having a syndiotactic configuration are excellent in mechanical strength, heat resistance, appearance and solvent resistance, and a variety of its uses have been expected. However, some of the styrenic polymers having the syndiotactic configuration obtained by known polymerization methods are poor in mechanical strength and heat resistance to be expected, and they are impracticable on occasion. The polymers having such a problem were investigated from various angles. That is to say, each of the styrenic polymers having the syndiotactic configuration was dissolved in 1,2,4-trichlorobenzene and then cooled to obtain a gel, and this gel was extracted with methylene chloride. In consequence, it has been found that as the amount of a methylene chloride extract increases, there occur the deterioration of the breaking strength of stretched films and the deterioration of the Izod impact strength, heat deformation temperature and breaking strength under long-term heating of injection-molded articles. In addition, it has also been found that when the molded articles of such polymers are intermittently or continuously used at a high temperature, the deterioration of the surface gloss of these molded articles occurs.
Accordingly, in order to further spread the uses of the styrenic polymers (hereinafter abbreviated to "SPS" sometimes) having the syndiotactic configuration by the utilization of characteristics peculiar to the styrenic polymers, the above-mentioned problems are required to be solved.
DISCLOSURE OF THE INVENTION
Objects of the present invention are to develop a styrenic polymer having a syndiotactic configuration which can decrease the amount of a methylene chloride extract from a gel obtained by cooling a 1,2,4-trichlorobenzene solution and which does not bring about the deterioration of the breaking strength of stretched films, the deterioration of Izod impact strength, heat deformation temperature and breaking strength under long-term heating of injection-molded articles, and the deterioration of the surface gloss of these molded articles by their intermittent or continuous use at a high temperature, and to develop a molded article of the above-mentioned styrenic polymer.
Now, the present inventors have intensively researched to solve the above-mentioned problems, and as a result, it has been found that a styrenic polymer having a syndiotactic configuration which is within a specific molecular weight range and in which the amount of a methylene chloride extract is 10% by weight or less can achieve the above-mentioned objects. In consequence, the present invention has been completed on the basis of such knowledge.
That is to say, the present invention provides a styrenic polymer having a highly syndiotactic configuration in which the weight-average molecular weight of the styrenic polymer is in the range of 1.times.10.sup.4 to 2.times.10.sup.6 and in which the weight fraction of an extract extracted with methylene chloride from a gel obtained by dissolving the styrenic polymer in 1,2,4-trichlorobenzene and then cooling the solution is 10% by weight or less, and a molded article comprising the above-mentioned polymer.
BEST MODE FOR CARRYING OUT THE INVENTION
A styrenic polymer of the present invention has a highly syndiotactic configuration, but here, the highly syndiotactic configuration means that its stereochemical structure has a highly syndiotactic configuration, i.e., a steric structure in which phenyl groups and substituted phenyl groups which are side chains are located alternately in opposite directions on a main chain comprising carbon-carbon bonds. Its tacticity can be quantitatively determin
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Aoyama Takuma
Masuyama Akitoshi
Uchida Takaaki
Yamasaki Komei
Idemitsu Petrochemical Co. Ltd.
Teskin Fred
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