Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-11-28
2002-03-12
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
06355767
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an aromatic polycarbonate resin composition having excellent mechanical strength and excellent resistance to moist heat. More specifically, it relates to an aromatic polycarbonate resin composition which has excellent mechanical strength, particularly falling weight impact strength, and improved hydrolysis resistance under a moist heat environment.
PRIOR ART
An aromatic polycarbonate resin is widely used thanks to its excellent mechanical properties such as impact resistance as well as excellent heat resistance and transparency. The methods of producing such an aromatic polycarbonate resin include one in which phosgene is directly reacted with a diphenol such as bisphenol A in a halogen compound solvent such as methylene chloride (interfacial polymerization), one in which an ester exchange reaction is carried out between a diphenol such as bisphenol and a carbonate ester such as diphenyl carbonate for polymerization (may be referred to as “melting method” hereinafter), and the like. Out of these production methods, one in which an ester exchange reaction is carried out between a diphenol and a carbonate ester is the most promising technology because it is free from problems caused by using phosgene and a halogen compound such as methylene chloride and has such an advantage that an aromatic polycarbonate resin can be produced at a low cost with a small load on environment.
Further, a resin composition comprising an aromatic polycarbonate resin and a thermoplastic graft copolymer resin (to be abbreviated as “ABS resin” hereinafter) obtained by grafting a vinyl cyanide monomer component and an aromatic vinyl monomer component to a diene-based rubber has excellent economical efficiency (a reduction in costs) and such an excellent feature that the moldability, platability and mechanical properties, particularly the dependence of impact resistance upon thickness in an Izod impact test, of an aromatic polycarbonate resin can be improved. Therefore, it is widely used in industrial fields such as housings for office equipment and portable electronic equipment, and car interior parts.
However, a resin composition obtained by mixing ABS resin with an aromatic polycarbonate resin has such a problem as deterioration in weld strength and falling weight impact strength compared with an aromatic polycarbonate resin alone. Particularly, office equipment and portable electronic equipment require high breaking strength at the time of falling and car interior parts require high breaking strength against impact at the time of a collision or the like. Further, a general Izod impact test is carried out as a standard test to obtain numerical values of impact strength of actual products of the above resin composition, but general Izod impact test values of the above resin composition are not so correlated to the impact strength values of the actual products. Therefore, actual products of a resin composition comprising an elastic material such as rubber are unsatisfactory in terms of impact strength in most cases even if the notched impact value of the resin composition is satisfactory. In this case, impact strength obtained by a falling weight impact test in which breaking strength is measured by colliding a ball or punch against one side of a test piece or the surface of a product at a high speed to give an impact is closely correlated to the strength of an actual product. Further, plastic moldings such as office equipment, portable electronic equipment and car interiors are strongly desired to be thin and lightweight because great importance is attached to the light weight, designability and portability of products. Sufficient impact resistance is required of even thin moldings. Particularly in these fields, impact strength obtained by a falling weight impact test has a great influence upon the characteristic properties of a product.
A resin composition comprising an aromatic polycarbonate resin and a thermoplastic graft copolymer obtained by grafting a vinyl cyanide monomer component and an aromatic vinyl monomer component to a diene-based rubber is disclosed by JP-B 7-98892 (the term “JP-B” as used herein means an “examined Japanese patent publication”). This aromatic polycarbonate resin is an aromatic polycarbonate resin substantially produced by the melting method. It is disclosed that this composition is superior in weld strength to a composition comprising an aromatic polycarbonate resin produced by the interfacial polymerization method. However, the impact resistance of the composition of this invention, particularly the falling weight impact resistance which is closely correlated to product strength is not improved and the falling weight impact strength of a thin molded product of the composition is still unsatisfactory.
JP-A 9-143356 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses a resin composition prepared by blending a metal salt compound with a mixed resin of an aromatic polycarbonate resin produced by the melting method and ABS resin. It is taught that this composition is excellent in weld strength, dry heat resistance at high temperatures and flame retardancy. However, when a metal salt compound is blended with an aromatic polycarbonate resin, there arise such problems as a deterioration in moist heat resistance such as the reduction in mechanical strength and the worsening of surface appearance because hydrolysis is promoted during long-time use or under a moist heat environment. This publication is utterly silent about a resin composition having excellent mechanical strength and moist heat resistance.
Meanwhile, great importance has been recently attached to the performance retention during long-time use from perspective which is safety and recyclability of a product, a reduction in environmental load by extending the service life of a product and the guarantee of a product by a manufacturer.
Under the situation, an aromatic polycarbonate resin composition which has excellent mechanical strength, particularly falling weight impact strength, and improved hydrolysis resistance under a moist heat environment has been desired.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an aromatic polycarbonate resin composition which has excellent mechanical strength, particularly falling weight impact strength, and improved hydrolysis resistance under a moist heat environment.
The inventor of the present invention have conducted intensive studies to achieve the above object of the present invention and have surprisingly found that a resin composition comprising an aromatic polycarbonate resin having a specific terminal hydroxyl group concentration produced by an ester exchange reaction and a thermoplastic graft copolymer resin produced by grafting a specific amount of a vinyl cyanide monomer component and containing a vinyl cyanide monomer in a specific amount or less has excellent falling weight impact strength particularly in a thin portion and improved hydrolysis resistance under a moist heat environment. The present invention has been accomplished based on this finding.
According to the present invention, there is provided an aromatic polycarbonate resin composition comprising: (1) 10 to 90 wt % of an aromatic polycarbonate resin (component A) which is obtained by an ester exchange reaction between a diphenol and a dicarbonate ester and has a terminal hydroxyl group concentration of amount of 10 to 70 mol % based on 100 mol % of the total of all the terminal groups, and (2) 90 to 10 wt % of a thermoplastic graft copolymer resin (component B) which is obtained by grafting a vinyl cyanide monomer component and an aromatic vinyl monomer component to a diene-based rubber, the proportion of the vinyl cyanide monomer component to the copolymer resin being 10 to 27 wt % and the amount of a vinyl cyanide monomer contained in the copolymer resin being 200 ppm or less.
Further, according to the present invention, there are provided aromatic polycarbonate resin co
Boykin Terressa M.
Teijin Chemicals, LTD
LandOfFree
Aromatic polycarbonate resin composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aromatic polycarbonate resin composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aromatic polycarbonate resin composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2872188