Organic compounds -- part of the class 532-570 series – Organic compounds – Carbonate esters
Reexamination Certificate
2000-05-26
2002-11-05
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbonate esters
C528S271000
Reexamination Certificate
active
06476249
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polycarbonate copolymer with reduced monomers and others remaining therein, and to a method for producing it. Precisely, the invention relates to an aromatic polycarbonate copolymer copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols, and to a method for producing it. The method comprises preparing a prepolymer through melt prepolymerization followed by polymerizing the prepolymer in a solid phase or in a swollen solid phase to give the polycarbonate copolymer.
BACKGROUND ART
For producing aromatic polycarbonates, known are a method of directly reacting an aromatic dihydroxy compound such as bisphenol A or the like with phosgene (interfacial polycondensation), and a method of transesterifying an aromatic dihydroxy compound such as bisphenol A or the like with a dicarbonate such as diphenyl carbonate or the like (melt polymerization, solid-phase polymerization).
However, the interfacial polycondensation method is problematic in that it requires toxic phosgene and the chlorine-containing side products formed corrode the apparatus used. On the other hand, the melt polymerization method is free from the problem, but is confronted with another problem in that the amount of monomers and other low-molecular-weight substances such as acetone-soluble substances remaining in the polymers produced is large. As a result, the impact resistance of the polymers is low, and the polymers are difficult to release from molds.
To reduce monomers that may remain in polymers produced through melt polymerization, proposed was adding a low-boiling-point compound to the polymerization system in extruders (Japanese Patent Laid-Open Nos. 59367/1997, 59368/1997, 67433/1997, 157375/1997, 156000/1993, 157586/1996), but this is still unsatisfactory. No report is found, relating to solid-phase polymerization to give aromatic polycarbonates copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols.
The present invention is to provide an aromatic polycarbonate copolymer copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols, in which the remaining monomers, acetone-soluble substances (low-molecular-weight substances) and cyclic oligomers are all reduced and of which the terminal hydroxyl content is also reduced, and to provide a method for producing the copolymer.
DISCLOSURE OF THE INVENTION
Having assiduously studied the problems noted above, the present inventor has completed the invention, which includes the following:
[1] An aromatic polycarbonate copolymer with units of an aromatic dihydroxy compound being copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols via a carbonate group therebetween, of which the total of the dihydroxy compound content, the dicarbonate content and the monohydroxy compound content is smaller than 100 ppm.
[2] An aromatic polycarbonate copolymer with units of an aromatic dihydroxy compound being copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols via a carbonate group therebetween, of which the dihydroxy compound content is smaller than 100 ppm.
[3] An aromatic polycarbonate copolymer with units of an aromatic dihydroxy compound being copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols via a carbonate group therebetween, of which the acetone soluble content is at most 3.0% by weight.
[4] An aromatic polycarbonate copolymer with units of an aromatic dihydroxy compound being copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols via a carbonate group therebetween, of which the cyclic oligomer content is at most 0.45% by weight.
[5] An aromatic polycarbonate copolymer with units of an aromatic dihydroxy compound being copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols via a carbonate group therebetween, of which the terminal hydroxyl fraction is at most 20% by mol.
[6] An optical material comprising the polycarbonate copolymer of any of above [1] to [5].
[7] A method for producing a polycarbonate copolymer through transesterification of (A) an aromatic dihydroxy compound and (B) at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols with (C) a dicarbonate, which comprises prepolymerizing the dihydroxy compound, at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols, and the dicarbonate under heat to give a polycarbonate prepolymer, followed by polymerizing the prepolymer in a solid or swollen solid phase in the presence of a quaternary phosphonium salt serving as a catalyst.
[8] The method for producing a polycarbonate copolymer of above [7], wherein a nitrogen-containing, organic basic compound that serves as a catalyst is used in the prepolymerization step to give the polycarbonate prepolymer.
[9] The method for producing a polycarbonate copolymer of above [7] or [8], wherein the polycarbonate prepolymer is polymerized in an atmosphere containing at least one gas selected from the group consisting of bad solvent gases, swelling solvent gases and inert gases, in a solid or swollen solid phase in the presence of a quaternary phosphonium salt serving as a catalyst.
BEST MODES OF CARRYING OUT THE INVENTION
[I] Polycarbonate Copolymer
The polycarbonate copolymer of the invention comprises units of an aromatic dihydroxy compound copolymerized with at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohol via a carbonate group therebetween, and the amount of the monomers remaining in the copolymer is smaller than 100 ppm in terms of the total of the dihydroxy compound content, the dicarbonate content and the monohydroxy compound content of the copolymer.
The organosiloxane unit-having copolymer of the invention is an improvement on ordinary aromatic polycarbonates in point of its flame retardancy, fluidity, impact resistance and mold releasability. This is especially favorable to optical materials, as being well molded into non-halogen, flame-retardant, thin-walled moldings with good distortion resistance.
The copolymer of the present invention having a unit of the organosiloxane is a random, block or graft copolymer which comprises units of an aromatic dihydroxy compound copolymerized with a polyorganosiloxane via a carbonate group therebetween. In this, the organosiloxane units and the aromatic dihydroxy-carbonate units are represented by the following formulae (1) and (2), respectively.
wherein R
1
to R
4
each represent an alkyl group having from 1 to 8 carbon atoms (e.g., methyl group, ethyl group, propyl group, n-butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, etc.), or an aryl group having from 6 to 20, but preferably from 6 to 18 carbon atoms (e.g., phenyl group, tolyl group, xylyl group, naphthyl group, etc.), and these may be the same or different; A represents a divalent organic residue including an aliphatic or aromatic group, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an ethylidene group, an isopropylidene group, a cyclopentylene group, a cyclohexylene group, a cyclopentylidene group, a cyclohexylidene group, etc., or an o-allylphenol residue, a p-vinylphenol residue, an eugenol residue, a bisphenol A residue, etc.; and n falls between 0 ad 500.
wherein R
5
and R
6
each represent a halogen atom of fluorine, chlorine, bromine or iodine, an alkyl group having from 1 to 8 carbon
Idemitsu Petrochemical Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Shaver Paul F.
LandOfFree
Copolycarbonate and process for producing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Copolycarbonate and process for producing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Copolycarbonate and process for producing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2928422