Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-12-14
2001-11-27
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
06323302
ABSTRACT:
FIELD OF THE INVENTION
Some of the present invention relates to a method for producing an aromatic polycarbonate, more particularly relates to a method for stably and economically producing an aromatic polycarbonate having a good quality by a melt polycondensation reactions
Further, some other part of the present invention relates to a method for producing an aromatic polycarbonate excellent in heat stability and hue.
Further, some other part of the present invention relates to a method for producing an aromatic polycarbonate by recycling a monohydroxy compound produced as a byproduct from the said melt polycondensation reaction and using as a solvent for a catalyst in producing the aromatic polycarbonate by the melt polycondensation reaction.
Further, some other part of the present invention relates to the production of a carbonic diester as a raw material for the production of an aromatic polycarbonate and of an aromatic polycarbonate produced therefrom, more particularly, to the carbonic acid diester good in storing stability, and an aromatic polycarbonate having an improved quality and color tone, which is produced from the said carbonic acid diester.
Further, some other part of the present invention relates to a method for producing a polycarbonate, more particularly to a method for producing an aromatic polycarbonate, the generation of foreign materials being suppressed, by using reaction facilities composed of a stainless alloy containing a specific amount of a specific metal in producing the aromatic polycarbonate by an ester interchange reaction of a dihydroxy compound with a carbonic acid diester compound.
Further, some other part of the present invention relates to facilities for producing an aromatic polycarbonate, more particularly to facilities having a specific oxide film layer. The facilities disclosed in the present invention are preferable for producing an aromatic polycarbonate by the melt ester interchange method and suitable for producing an aromatic polycarbonate containing a reduced amount of foreign materials, typically fine foreign materials, in the polymer.
In the statement of the present description and claims, “aromatic dihydroxy compound” is sometimes called as “aromatic diol compound”, “catalyst deactivation agent” is sometimes called as “catalyst inactivation agent”, and “end-capping agent” is sometimes called as “terminal blocking agent”.
Further, the “foreign materials” are constituted by black foreign materials represented by polymer degradation materials, fine crystals of aromatic polycarbonate, dust, dirt, sand, etc., derived from the outside, besides “gels” derived from a cross-linked molecular structure. Especially, the gel state foreign materials are also called as “gels” or “gel foreign materials”. When referring to “fine foreign materials”, it means mainly smaller materials in the “foreign materials”, specifically those having the size of 10&mgr; or smaller.
PRIOR ARTS
An aromatic polycarbonate resin is excellent in mechanical characteristics such as impact resistance, and also in heat resistance and transparency, and used widely as a molding material. As the method for producing such an aromatic polycarbonate, a method for directly reacting an aromatic dihydroxy compound such as bisphenol with phosgene (an interfacial method), and a method for performing an ester interchange reaction of an aromatic dihydroxy compound such as bisphenol with a carbonic acid diester such as diphenyl carbonate (a molten method) are known.
Among such production methods, the method for producing an aromatic polycarbonate by the ester interchange reaction of an aromatic dihydroxy compound with a carbonic acid diester is drawing attention because it is a method benevolent to the environment without using harmful phosgene or methylene chloride, and also because it is pointed out that there is a possibility that this method is better in view of its cost than the interfacial method.
However, as to the quality of the aromatic polycarbonate obtained by the melting method, it is difficult to obtain an excellent quality material because of deteriorated color tone, etc., due to severe reaction conditions, etc. In recent years, further improvements in color tone and heat stability are required for the aromatic polycarbonate used for a substrate of an optical information recording medium such as DVD, CD, MO, etc., since a discoloration due to the lack of heat stability and a gelation due to a thermal transformation, directly affect optical characteristics such as a block error rate, etc., and mechanical characteristics such as tensile, flexural properties, toughness, etc.
Further, as to the carbonic acid diester used as a raw material for the aromatic polycarbonate, diphenyl carbonate is preferably used, but diphenyl carbonate has been conventionally produced by reading phosgene with phenol in the presence of an acid capturing agent, preferably using a basic catalyst.
Diphenyl carbonate produced by the above method usually contains chlorine compounds derived from phosgene used as the raw material or an intermediate chloroformate, but since the chlorine compounds give adverse effect on the color tone of the polymer, attention has been drawn to the chlorine compounds and various purification processes have been proposed to decrease them.
For example, various purification processes were proposed in Japanese Patent Publication Sho 38-18686; Method for producing diphenyl carbonate using a basic catalyst such as an amine, Japanese Patent Publication Sho 41-10812; Removal of chloroformate by a surfactant, Plastic Material Course (vol. 17), page 4-47, published by Nikkan Kogyou Shinbunsha, etc. However, the diphenyl carbonate produced or purified by such a method usually contains, as an impurity, a nitrogen-containing compound having used as the catalyst.
Also, recently a method for directly producing diphenyl carbonate from phenol and carbon monoxide in the presence of a group 8 noble metal catalyst is attracting attention as a method without using phosgene.
In the above process, for example in Japanese Unexamined Patent Publication Hei 7-188,116 (Bayer Co., Ltd.), a quaternary ammonium salt was stated as an indispensable component of the catalyst system, but there was a problem in that thus produced diphenyl carbonate usually contains a nitrogen-containing compound as an impurity.
Regarding the facility materials, there have been various problem as follows.
In recent years, for the aromatic polycarbonate used for an optical disc, etc., a material showing a small error rate is desired in accordance with the improvement in recording density, that is, a polymer having a reduced amount of foreign materials represented by fine foreign materials, one of the causes of error rate generation, has been desired for the aromatic polycarbonate satisfying these demands.
For this purpose, as a method for producing an aromatic polycarbonate by the ester interchange method, various studies have been made up to now. For example, in Japanese Unexamined Patent Publication Hei 9-241370, a method for producing a high molecular weight aromatic polycarbonate having a good color tone by using a material with a quality substantially not having FeOOH, CrOOH and NiOOH components which are usually existing at the surface of a part contacting a liquid, was disclosed.
In Japanese Unexamined Patent Publication Hei 8-277327, a method for producing a high molecular weight aromatic polycarbonate having a good color tone by a heat treatment of the stainless steel part to be in contact with the liquid, is disclosed. And also, in Japanese Patent Publication Hei 8-5957, a method for producing the aromatic polycarbonate having a good hue by performing the reaction in the reaction facilities in which parts contacting the reaction mixture are composed of a metal or an alloy comprising 85% by weight or more of copper and/or nickel was disclosed.
In Japanese Unexamined Patent Publication Hei 6-345860, a method for producing a high molecular weight aromatic polycarbonate excellent in heat resistance, hydrolysis resista
Abe Masanori
Funakoshi Wataru
Hirata Masumi
Kaneko Hiroaki
Matsuo Jyuhou
Boykin Terressa M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Teijin Limited
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