Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1997-10-15
1999-08-03
Mosley, Terressa
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C08G 6400
Patent
active
059326832
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polycarbonate having heterounits and a method for producing the same. More particularly, the present invention is concerned with a polycarbonate comprising a plurality of aromatic polycarbonate main chains, wherein the aromatic polycarbonate main chains collectively contain specific heterounits in a specific amount in the polycarbonate main chains, and a method for producing the same. The polycarbonate of the present invention is advantageous in that not only does it have high transparency and colorlessness as well as high mechanical strength, but also it can exhibit high non-Newtonian flow properties, so that it exhibits high molding melt fluidity. Therefore, the polycarbonate of the present invention is extremely advantageous from a commercial point of view.
2. Prior Art
Polycarbonates have been widely used in various fields as engineering plastics having excellent heat resistance, impact resistance and transparency. Production of polycarbonates has conventionally been conducted by using the phosgene process. However, polycarbonates produced by using the phosgene process have problems in that the production thereof needs the use of phosgene, which is poisonous, and that they contain residual methylene chloride (solvent), which not only adversely affects the thermal stability of the polycarbonates, but also causes corrosion of a mold used for the molding of the polycarbonates. Therefore, recently, polycarbonates produced by using the transesterification process have been drawing attention.
With respect to transesterification polycarbonates, it is known: that almost colorless, transparent transesterification can be obtained on a laboratory scale; however, when the production of transesterification polycarbonates is conducted on a commercial scale, only those having (5), Porikaboneto Jushi (Lecture on Plastic Materials (5), Polycarbonate Resins)", page 66, published in 1981 by The Nikkan Kogyo Shimbun Ltd., Japan!, and that transesterification polycarbonates have disadvantages in that they have many branched structures, so that they have poor strength (danger of brittle fracture is high), as compared to phosgene process
In order to alleviate these problems of the transesterification polycarbonates, various studies have been made on the structure and production process of the transesterification polycarbonates. With respect to the branched structures of the transesterification polycarbonates, it is known that such branched structures are formed as follows. During the progress of the polymerization reaction in the presence of an alkali in the reaction system, the polycarbonate chain being formed suffers a side reaction represented by the reaction formula described below, which is similar to the Kolbe-Schmitt reaction: ##STR1## As is apparent from the above-shown structure formed in the main chain by the side reaction, a branched chain grows and extends through ester bonds. In some cases, such a branched chain forms a crosslinked structure in the (Lecture on Plastic Materials (5), Polycarbonate Resins)", page 64, published in 1981 by The Nikkan Kogyo Shimbun Ltd., Japan; and "Porikaboneto Jushi Hando Bukku (Polycarbonate Resin Hand Book)", page 49, published in 1992 by The Nikkan Kogyo Shimbun Ltd., Japan!.
With respect to the structure of the transesterification polycarbonate, it has been attempted to reduce the amount of branched structure in the polycarbonate. For example, Unexamined Japanese Patent Application Laid-Open Specification No. 5-105751 and Unexamined Japanese Patent Application Laid-Open Specification No. 5-202180 (corresponding to U.S. Pat. No. 5,468,836) disclose a technique to obtain a transesterification polycarbonate having no or an extremely small amount of branched structure. Specifically, in these prior art documents, the transesterification reaction is conducted using a specific combination of catalysts, to thereby obtain a colorless, transparent polycarbonate having no or an extremely small amount
REFERENCES:
patent: 4562242 (1985-12-01), Mark et al.
patent: 5418316 (1995-05-01), Kuhling et al.
patent: 5468836 (1995-11-01), Okano et al.
Hachiya Hiroshi
Kazunori Miyuki
Komiya Kyosuke
Asahi Kasei Kogyo Kabushiki Kaisha
Mosley Terressa
LandOfFree
Polycarbonate comprising different kinds of bonding units and pr does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polycarbonate comprising different kinds of bonding units and pr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polycarbonate comprising different kinds of bonding units and pr will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-850347