Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-09-26
2002-10-08
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
06462165
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to polycarbonates, more precisely to those having a reduced content of impurities such as remaining monomers and oligomers and having excellent physical properties such as impact strength, and also to optical materials and blow molding materials.
DESCRIPTION OF THE BACKGROUND
Polycarbonates are excellent engineering plastics and are widely used in various fields. For producing them, known are a method of directly reacting an aromatic dihydroxy compound such as bisphenol A or the like with phosgene (interfacial process), and a method of transesterifying a dicarbonate such as diphenyl carbonate or the like with an aromatic dihydroxy compound such as bisphenol A or the like in a melt:or solid phase (melt-phase process, solid-phase process).
However, the interfacial process is problematic in that it requires toxic phosgene, the chlorine-containing side products such as hydrogen chloride, sodium chloride and the like formed corrode the apparatus used, and methylene chloride that may be in the resins formed is extremely difficult to remove and therefore the polycarbonates formed often contain chlorine.
On the other hand, the melt-phase process is free from the problems with the interfacial process, but is confronted with another problem in that the amount of monomers and other low-molecular-weight substances remaining in the polymers produced is large. As a result, the impact resistance of the polymers is low, and the polymers often adhere to molds.
To solve the problems, a method of adding a low-boiling-point compound to extruders in the melt-phase process has been proposed (Japanese Patent Laid-Open No. 5936/1997), but it is not still satisfactory. Neither proposal nor report is known, relating to the improvement in the solid-phase process.
The present invention is to solve the problems with polycarbonates produced through conventional transesterification, and to provide high-quality polycarbonates having good impact resistance and also optical materials and blow molding materials.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
We, the present inventors have assiduously studied to attain the object as above, and, as a result, have found that high-quality polycarbonates containing an extremely reduced amount of monomers and low-molecular-weight substances remaining therein can be obtained through transesterification by properly selecting the reaction method and the reaction condition to be employed. On the basis of this finding, we have completed the present invention.
Specifically, the invention provides polycarbonates described below.
[1] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase, swollen solid-phase or thin film melt-phase transesterification, of which the total of the dihydroxy compound content, the dicarbonate content and the monohydroxy compound content is smaller than 100 ppm.
[2] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase, swollen solid-phase or thin film melt-phase transesterification, of which the dihydroxy compound content is smaller than 100 ppm.
[3] A polycarbonate obtained through transesterification of a dihydroxy compound and a dicarbonate, of which the acetone soluble content is at most 2.0% by weight.
[4] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through thin film melt-phase transesterification, of which the acetone soluble content is at most 3.0% by weight.
[5] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase or swollen solid-phase transesterification, of which the acetone soluble content is at most 3.5% by weight.
[6] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase or swollen solid-phase transesterification, of which the terminal hydroxyl fraction is smaller than 2 mol %.
[7] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through thin film melt-phase transesterification, of which the terminal hydroxyl fraction is smaller than 15 mol %.
[8] A polycarbonate obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase, swollen solid-phase or thin film melt-phase transesterification, of which the cyclic oligomer content is at most 0.45% by weight.
[9] The polycarbonate of above [1], [2], [5] or [8], for which the polycarbonate prepolymer is prepared through thermal prepolymerization of (A) an aromatic dihydroxy compound, (B) a dicarbonate and (C) a monohydroxy compound.
[10] A polycarbonate obtained by preparing a polycarbonate prepolymer through thermal prepolymerization of (A) an aromatic dihydroxy compound, (B) a dicarbonate and (C) a monohydroxy compound followed by polymerizing the prepolymer through solid-phase or swollen solid-phase transesterification, of which the monohydroxy compound-derived terminal fraction is at least 50 mol %.
[11] A polycarbonate obtained by preparing a polycarbonate prepolymer through thermal prepolymerization of (A) an aromatic dihydroxy compound, (B) a dicarbonate and (C) a monohydroxy compound followed by polymerizing the prepolymer through solid-phase or swollen solid-phase transesterification, of which the terminal hydroxyl fraction is smaller than 15 mol %.
[12] An optical material comprising the polycarbonate of any of above [1] to [11].
[13] The polycarbonate of any of above [1], [2], [5] or [8], for which the polycarbonate prepolymer is prepared through thermal prepolymerization of (A) an aromatic dihydroxy compound, (B) a dicarbonate and (C) a poly-functional organic compound having at least three functional groups.
[14] A polycarbonate obtained by preparing a polycarbonate prepolymer through thermal prepolymerization of (A) an aromatic dihydroxy compound, (B) a dicarbonate and (C) a poly-functional organic compound having at least three functional groups, followed by polymerizing the prepolymer through solid-phase or swollen solid-phase transesterification, of which the terminal hydroxyl fraction is smaller than 15 mol %.
[15] A blow molding material comprising the polycarbonate of above [13] or [14].
BEST MODES OF CARRYING OUT THE INVENTION
The polycarbonate of the invention includes those obtained through melt-phase or solid-phase transesterification of starting materials, (A) a dihydroxy compound and (B) a dicarbonate, and optionally (C) a terminating agent or a branching agent, especially those obtained by preparing a polycarbonate prepolymer through prepolymerization of (A) a dihydroxy compound and (B) a dicarbonateorphosgene, andoptionally (C) a terminating agent or a branching agent, followed by polymerizing the prepolymer through solid-phase, swollen solid-phase or thin film melt-phase transesterification. In preparing the polycarbonate prepolymer and polymerizing it, catalysts are used.
1. Characteristics of Polycarbonates of the Invention:
(1) In one aspect, the polycarbonate of the invention is obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing the prepolymer through solid-phase, swollen solid-phase or thin film melt-phase transesterification, and the total of the dihydroxy compound content, the dicarbonate content and the monohydroxy compound content of the polycarbonate is smaller than 100 ppm. The dihydroxy compound content, the dicarbonate content and the monohydroxy compound content
Ito Mitsunori
Kuze Shigeki
Boykin Terressa M.
Idemitsu Petrochemical Co. Ltd.
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