Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1992-06-04
1995-03-21
Kight, III, John
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
528182, 528176, C08G 6302, C08G 6300
Patent
active
053996569
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a heat-resistant aromatic polyester having a resorcinol structure which is superior in heat resistance, mechanical properties and melt-moldability and has very good lightness and color tone; and a method for producing the same.
BACKGROUND ART
The technologies in such fields as electric, electronic, office automation (OA), audio-visual (AV), and automotive industries have been making remarkable progress in recent years. Polymeric materials used in such new fields are required to have meritorious properties such as high strength and high heat resistance. They have come to be required to have high level properties such as high dimensional accuracy, strength, rigidity, solder heat resistance and thin-wall processability by the advancement of reduction of the size and wall thickness particularly of electric parts such as relay parts, coil bobbins and connectors. As one of the polymeric materials which can satisfy the requirements, aromatic polyesters are suitably used. Among the aromatic polyesters, particularly aromatic polyesters showing liquid crystalline property in molten state have desirable thin-wall processability and are rapidly coming into wide use as a material for electric parts.
However, the aromatic polyesters showing liquid crystalline property in molten state have such disadvantages as low impact resistance, low weld strength and high irregularity of shrinkage in every direction. Therefore, in fact, the improvement of these disadvantages has been strongly desired. Since these disadvantages are expected to be overcome by reducing the liquid crystalline property of the polyesters, the introduction of nucleus-substituted structure or a bending structure into the polymer chains, addition of glass fibers, etc. are now under investigation.
The aromatic polyesters showing liquid crystalline property in molten state have high heat resistance due to their stiff molecular chains. However, because of this, they have to be molded at elevated temperatures. Therefore, in some application fields wherein the reduction of heat resistance is accepted to some degree, there has been a strong requirement of developing an aromatic polyester showing liquid crystalline property in molten state which can be molded at relatively low temperatures. The introduction of a nucleus-substituted structure or a bending structure into the polymer chains has been likewise tried in order to lower the melting point of the polyesters without damaging their mechanical properties, thereby improving the moldability. When a notice is given to the introduction of a bending structure into the polymer chains, the use of resorcinol as a bending monomer is particularly of technical interest in view of its easy availability in industry.
Although acetylation method, phenyl esterification method and acid chloride method are known as the methods for producing aromatic polyesters, the aromatic polyesters showing liquid crystal property in molten state are mostly produced by acetylation method, in which polymerization is carried out by solution polymerization in a solvent having a high boiling point or by melt polymerization using substantially no solvent. In acetylation method, an aromatic hydroxy compound, one of the monomers, is converted into an acetic acid ester by the reaction between an aromatic hydroxy compound and acetic anhydride and the acetic acid ester is then polymerized by the intermolecular elimination of acetic acid. The conversion of an aromatic hydroxy compound into an acetic acid ester is generally conducted by adding acetic anhydride in an excess amount of about 1.1 moles per mole of the hydroxyl group and allowing the resulting mixture to react under reflux of acetic anhydride.
However, the preparation of resorcinol diacetate by the above method problematically accompanies the coloring of the reaction product and the formation of by-products. The purification of the colored reaction product by distillation under reduced pressure is still insufficient to obtain resorcinol diac
REFERENCES:
patent: 4188476 (1980-02-01), Irwin
patent: 4318841 (1982-03-01), East et al.
patent: 4749769 (1988-06-01), Kock et al.
patent: 4749770 (1988-06-01), Kock et al.
patent: 4861858 (1989-08-01), Kock et al.
Databese WPI, Week 7005, Derwent Publications Ltd., London, GB; AN 70-065105 & JP-A-45 001 606 (Chugai Pharmaceutical Co).
Asai Kuniaki
Harada Hiroshi
Nitta Itaru
Kight III John
Mosley T.
Sumitomo Chemical Company Limited
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