Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-10-07
2001-09-11
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
06288204
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field on the Invention
The present invention relates to a branched polycarbonate resin in which a content of gel like peculiar substances to exert an influence upon appearance and mechanical properties is small and a process for producing the same.
2. Prior Art
Hitherto, polycarbonate resin has been used in a wide range as engineering plastic excellent in transparency, mechanical strength and heat stability. Polycarbonate resin can be molded by various molding methods. Particularly, when a large type of molded article was produced by blow molding or extrusion molding, Newtonian flowability became problematic and the phenomenon of so called drawdown due to weight of polycarbonate resin itself often occurred, so that it was difficult to obtain an intended molded article.
Accordingly, in order to prevent the drawdown, polycarbonate resin to reveal non-Newtonian flowability to a great extent is preferable. As a process for producing a polycarbonate resin having such property, i.e., suitable structural viscosity, processes to use a branching agent are known For example, Japanese Patent Publication Nos. 44-17149 and 47-23918 disclose branched polycarbonate resins used phloroglucin, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane-2,1,3,5-tri-(4-hydroxyphenyl)-benzol, 1,1,1-tri-(4-hydroxyphenyl) ethane, trimelltic acid, etc, as branching agent When the branching agent was used, molding was improved. However, there occurred the problem that a portion of properties of polycarbonate resin thus obtained, particularly, impact resistance was decreased.
In order to solve the problem for improvement of impact resistance, Japanese Patent Publication Nos. 6-84429 and 7-103235 disclose arts in which molecular weight of branched polycarbonate resin is specified and acetone soluble component is limited. Although impact resistance at a low temperature was improved in the arts, effect of improvement of impact resistance at a room temperature was not satisfactory. Further, molded articles used branched polycarbonate resin sometimes provided scattering of impact resistance value, so that further improvement has been desired.
On the other hand, when branching in branched polycarbonate resin proceeded to an exceeding extent, the problem of generation of solvent insoluble gel occurred. Japanese Patent Publication Nos. 3-15658, 3-42288 and 4-69178 disclose branched polycarbonate resins in which generation of solvent insoluble gel has been depressed by specifying a process for production of branched polycarbonate resin. However, the definition of the gel was not clear and there was no disclosure concerning influence of the gel to exert upon properties of branched polycarbonate resin.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a branched polycarbonate resin in which a non-dissolved gel like particle content in the branched polycarbonate resin solution is far smaller than that in conventional polycarbonate resin and blow molding and extrusion molding can be suitably applied and a process for producing the same.
As a result of extensive studies to solve the prior art problems, the inventors have found that a branched polycarbonate resin with excellent impact resistance at a room temperature can be obtained by optimizing a timing of addition of monomer(s), a branching agent, a tetraammonium salt, a molecular weight modifier and a polymerization catalyst, thereby decreasing a content of good solvent insoluble gel component with a particle diameter more than 50 &mgr;m as much as possible and accomplished the present invention.
That is, the present invention provides a branched polycarbonate resin having a viscosity average molecular weight (Mv) of 15,000 to 45,000, number of dichloromethane insoluble gel like particle with a particle diameter more than 50 &mgr;m being 10 or below per 100 g of the resin, obtained by reacting bisphenol, trihydric or above phenol as branching agent, monohydric phenol as molecular weight modifier and phosgene in the presence of both an alkali aqueous solution and organic solvent to polymerize.
Further, the present invention a process for producing a branched polycarbonate resin comprising the steps of:
reacting bisphenol, trihydric or above phenol as branching agent and phosgene in the presence of both an alkali aqueous solution and organic solvent,
then, further adding a tetraammonium salt to the reaction mixture,
thereby, starting polycondensation reaction,
then, adding both monohydric phenol as molecular weight modifier and a tertiary amine polymerization catalyst to the reaction mixture,
further performing polycondensation reaction, and
thereby, obtaining the branched polycarbonate resin having a viscosity average molecular weight (Mv) of 15,000 to 45,000, number of dichloromethane insoluble gel like particle with a particle diameter more than 50 &mgr;m being 10 or below per 100 g of the resin.
The present invention provides also a process for producing a branched polycarbonate resin comprising the steps of:
reacting bisphenol, trihydric or above phenol as branching agent and phosgene in the presence of both an alkali aqueous solution and organic solvent,
then, further adding a tetraammonium salt to the reaction mixture,
thereby, starting polycondensation reaction,
after a viscosity average molecular weight (Mv) of the reaction mixture containing the resultant products has reached to 3,000 above and less than 6,000, adding both monohydric phenol as molecular weight modifier and a tertiary amine polymerization catalyst to the reaction mixture,
further performing polycondensation reaction, and
thereby, obtaining the branched polycarbonate resin having a viscosity average molecular weight (Mv) of 15,000 to 45,000, number of dichloromethane insoluble gel like particle with a particle diameter more than 50 &mgr;m being 10 or below per 100 g of the resin.
REFERENCES:
patent: 44-17149 (1969-07-01), None
patent: 47-23918 (1972-07-01), None
patent: 3-15658 (1991-03-01), None
patent: 3-42288 (1991-06-01), None
patent: 4-69178 (1992-11-01), None
patent: 6-84429 (1994-10-01), None
patent: 7-103235 (1995-11-01), None
Adachi Takahiro
Honda Noriaki
Masumoto Mitsuhiko
Ogawa Noriyoshi
Boykin Terressa M.
Mitsubishi Gas Chemical Company Inc.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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