Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-11-13
2002-11-05
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S198000
Reexamination Certificate
active
06476179
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for producing a starting material for polycarbonate resin and to a method for producing polycarbonate resin. More precisely, the invention relates to an inexpensive and simple method for producing a starting material for polycarbonate resin and for producing polycarbonate resin.
BACKGROUND ART
Polycarbonate resin is a type of engineering plastics having well-balanced transparency, heat resistance and mechanical strength, and is used in many fields. Based on its overall characteristics of transparency, heat resistance, hydrolysis resistance and dimensional stability, polycarbonate resin is especially much used these days for raw materials for optical recording media such as compact discs, laser discs, optical memory cards, optical discs, digital video discs, etc. Polycarbonate resin of high transparency suitable to optical appliances including such optical recording media is produced through interfacial polymerization.
For producing polycarbonate resin through interfacial polymerization, generally employed is a method of reacting a bisphenol compound with phosgene. in the presence of an organic solvent and an aqueous alkali solution. For this, it is well known that a granulated solid bisphenol compound, which serves as the essential starting material for polycarbonate resin, is dissolved in an aqueous alkali solution and phosgene gas is introduced into the resulting solution.
The bisphenol compound, which is the essential starting material for polycarbonate resin, is granulated in a complicated process. For example, 2,2-bis(4-hydroxyphenyl)propane is, after produced through reaction of phenol with acetone, purified in many steps and then granulated in the final step. For granulating the bisphenol compound, used is a granulator such as a spray drier or the like, in which the bisphenol compound is formed into liquid drops and then cooled and solidified.
For producing polycarbonate resin from the bisphenol compound through interfacial polymerization, solid grains of the bisphenol compound having been solidified and granulated in the process as above are dissolved in an aqueous alkali solution, and the resulting solution is used in polycondensation.
The process for producing the bisphenol compound that serves as a starting material in producing polycarbonate resin through interfacial polymerization, and the process for producing polycarbonate resin require complicated many steps as in the above, and are therefore problematic in that many plants and much labor are needed and the production costs are high.
The present invention is to provide an inexpensive and simple method for producing a starting material for polycarbonate resin and for producing polycarbonate resin.
DISCLOSURE OF THE INVENTION
We, the present inventors have assiduously studied to solve the problems noted above, and, as a result, have found that, in a process for producing polycarbonate resin through interfacial polymerization, (I) when a bisphenol compound prepared in melt in a process of bisphenol compound production is, without being granulated, directly mixed in an aqueous alkali solution while it is in melt, and when the thus-prepared aqueous alkali solution of the bisphenol compound is used as the starting material for polycarbonate resin production, or (II) when a bisphenol compound prepared in melt in a process of bisphenol compound production is, without being solidified, directly mixed with water to be in liquid at a temperature not higher than the melting point of the bisphenol compound, and then dissolved in an aqueous alkali solution, and when the thus-prepared aqueous alkali solution of the bisphenol compound is used as the starting material for polycarbonate resin production through interfacial polymerization, then the above-mentioned object can be attained. On the basis of these findings, we have completed the present invention (including first and second aspects).
Specifically, the invention is summarized as follows:
I. First Aspect of the Invention
(1) A method for producing a starting material for polycarbonate resin production through interfacial polymerization, which is characterized in that a bisphenol compound prepared in melt in a process of bisphenol compound production is mixed and dissolved in an aqueous alkali solution at 20 to 80° C.
(2) The method for producing a starting material for polycarbonate resin of above (1), wherein the bisphenol compound includes bis(4-hydroxyphenyl)alkanes.
(3) A method for producing polycarbonate resin, which is characterized in that a bisphenol compound prepared in melt in a process of bisphenol compound production is mixed and dissolved in an aqueous alkali solution at 20 to 80° C, and the resulting aqueous alkali solution of the bisphenol compound is used as the starting material for polycarbonate resin production through interfacial polymerization.
II. Second Aspect of the Invention
(1) A method for producing a starting material for polycarbonate resin, which is characterized in that a bisphenol compound prepared in melt in a process of bisphenol compound production is, without being solidified, directly mixed with water to be in liquid at a temperature not higher than the melting point of the bisphenol compound, and then dissolved in an aqueous alkali solution.
(2) The method for producing a starting material for polycarbonate resin of above (1), wherein the bisphenol compound includes bis(4-hydroxyphenyl)alkanes.
(3) A method for producing polycarbonate resin, which is characterized in that a bisphenol compound prepared in melt in a process of bisphenol compound production is, without being solidified, directly mixed with water to be in liquid at a temperature not higher than the melting point of the bisphenol compound, and then dissolved in an aqueous alkali solution, and the resulting aqueous alkali solution of the bisphenol compound is used as the starting material for polycarbonate resin production through interfacial polymerization.
BEST MODE OF THE CARRYING OUT THE INVENTION
Modes of carrying out the invention are described hereinunder.
I. First Aspect of the Invention
In this section, the first aspect of the invention will be simply referred to as the invention.
In the method of the invention for producing a starting material for polycarbonate resin production through interfacial polymerization, a bisphenol compound prepared in melt in a process of bisphenol compound production is mixed and dissolved in an aqueous alkali solution at 20 to 80°C; and, in the method of the invention for producing polycarbonate resin, the resulting aqueous alkali solution of the bisphenol compound is used as the starting material for polycarbonate resin production.
In the method of the invention, the step of polycarbonate resin production through interfacial polymerization is per-se known. It comprises adding phosgene to the aqueous alkali solution of a bisphenol compound, with stirring it in the presence of an organic solvent such as methylene chloride or the like capable of well dissolving polycarbonate resin, to thereby form a polycarbonate oligomer having a chloroformate terminal, followed by further polymerizing the oligomer.
The bisphenol compound that serves as the essential starting material in the polycarbonate resin production includes, for example, 4,4′-dihydroxybiphenyls such as 4,4′-dihydroxybiphenyl, 3,3′-difluoro-4,4′-dihydroxybiphenyl, 4,4′-dihydroxy-3,3′-dimethyldiphenyl, 4,4′-dihydroxy-2,2′-dimethylbiphenyl, 4,4′-dihydroxy-3,3′-dicyclohexylbiphenyl, etc.; bis(4-hydroxyphenyl)methanes such as bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)phenylmethane, bis(3-methyl-4-hydroxyphenyl)methane, bis(3-nonyl-4-hydroxyphenyl)methane, bis(3,5-dimethyl-4-hydroxyphenyl)methane, bis(3,5-dibromo-4-hydroxyphenyl)methane, bis(3-chloro-4-hydroxyphenyl)methane, bis(3-fluoro-4-hydroxyphenyl)methane, bis(2-tert-butyl-4-hydroxyphenyl)phenylmethane,; bis(2-hydroxyphenyl)methanes such as bis(2-hydroxyphenyl)metha
Ito Hajime
Kohiruimaki Jun
Suwa Akio
Boykin Terressa M.
Idemitsu Petrochemical Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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