Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1992-10-02
1994-06-14
Kight, III, John
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
528176, 528193, 428480, C08G 6300, C08G 6302
Patent
active
053211251
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention concerns a molded body essentially consisting of one or several aromatic polyesters, namely polyarylates, which are manufactured from phthalic-acid halides and diphenols of formula ##STR1## where R is a bifunctional hydrocarbon residue containing at least one aromatic or cycloaliphatic ring. The invention moreover concerns an advantageous method for making such an article.
STATE OF THE ART
Articles of this kind are known for instance from the European patents 64,971 and 64,972, namely in the form of sheets made from a polyester solution by pouring. The polyester described in the European patent 64,972 is made from 1,1-bis(4-hydroxyphenyl)-phenylethane and it was found such can be processed only with difficulty because of the high required processing temperatures of 330.degree. to 400.degree. C., whereas the polyester of the European patent 64,971 made from 9,9-bis(4-hydroxyphenyl)-fluorene lacks any melting range at all, instead already starting to thermally decompose at a raised temperature of about 400.degree. C. The Russian publication PLASTICHESKIE MASSY, Nr. 7, 1976, p 56, "Physical properties of heat-resistant aromatic polymers", of which the English translation was published in INTERNATIONAL POLYMER SCIENCE AND TECHNOLOGY, vol. 3, #11, 1976, compares the properties of polyarylate films with blocks made of the same material molded at high temperatures. It was found that as rule the foils evince higher densities than blocks made of the same material but that the solubilities are the same in several common solvents. Now adequate solubility of such polyarylates in suitable solvents is the precondition for their being processed into films using pouring methods. On the other hand such solubility precludes many applications for polyarylates that demand substantial resistance to chemicals and solvents.
DISCUSSION OF THE INVENTION
The first object of the invention is to create an article of the initially cited kind which contrary to the case of the sheets shall be able to assume a substantially arbitrary three-dimensional shape and which also shall evince higher solvent resistance than poured foils made form the same plastic.
This problem is solved by the molded article of the invention, which is characterized in that it consists of a translucent, substantially pore-free sintered body with one or more glass transition point(s) in the range of 220.degree. to 400.degree. C. measured by the DSC method, further evincing a DIN 53455 tensile strength larger than 40N/mm.sup.2, advantageously however larger than 60N/mm.sup.2, and where a test specimen about 1.0 mm thick shall absorb hydrocarbon chloride at rates less than 1.0%, advantageously less than 0.8% of the specimen weight for a test duration of 24 h in a bath of carbon tetrachloride at 23.degree. C.
Now it was discovered that with equal kind and quality of the raw material, the sintered articles of the invention evince higher resistance to some solvents such as carbon tetrachloride compared to poured sheets. On this and other grounds which shall be further discussed below, it may be concluded with fair probability that the polyester substance forming the sintered article is crosslinked to some extent.
In one advantageous implementation of the invention, the sintered article of the invention consists essentially of an aromatic polyester based on 9,9-bis(4-hydroxyphenyl)-fluorene as diphenol. In another advantageous implementation of the sintered article of the invention, said article essentially consists of an aromatic polyester based on 1,1-bis-(4-hydroxyphenyl)-1-phenylethane and evinces a DIN 53455 tensile strength larger than 50N/mm.sup.2, in particular however larger than 70N/mm.sup.2.
Moreover the invention concerns an advantageous method for making the article molded in the manner of the invention. This method is characterized in that the aromatic polyester(s) in powder form are compacted under pressure, in that the compacted powder is slowly heated, while the pressure is maintained, to temperatures higher than the
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Datenbank Chemical Abstracts (STN), vol. 85, No. 18, 1976 (Columbus, Ohio, US), V. P. Sidorova et al.: "Physical Properties of Heat Resistant Aromatic Polymers", see Abstract No. 124795n & Plast. Massy, vol. 7, pp. 56-59, 1976.
Polymer Science U.S.S.R., vol. 21, 1979, (Oxford, GB), V. V. Korshak et al.: "Thermal Degradation of Pressure Moulded Aromatic Polyamides" pp. 34-38, see p. 32, lines 3-12.
Isonova Technische Innovationen Ges.m.b.H.
Kight III John
Mosley T.
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