Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-08-28
2004-04-27
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S263000, C524S267000, C524S155000, C524S156000, C524S166000
Reexamination Certificate
active
06727303
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a flame retardant aromatic polycarbonate resin composition and molded articles thereof. More specifically, it relates to a flame retardant aromatic polycarbonate resin composition which comprises substantially no bromine compound or chlorine compound (halogen-based flame retardant), or no phosphorus compound as a flame retardant and has excellent dripping preventing properties and to molded articles thereof. The present invention further relates to a flame retardant aromatic polycarbonate resin composition which provides molded articles having excellent transparency.
DESCRIPTION OF THE PRIOR ART
Aromatic polycarbonate resins and aromatic polycarbonate-based resins such as aromatic polycarbonate resin/styrene-based resin alloys and aromatic polycarbonate resin/aromatic polyester resin alloys are formed into various molded articles by a processing method which is simple and has excellent productivity, such as injection molding, and used in a wide variety of industrial fields. More specifically, aromatic polycarbonate resins and alloys thereof are used in exterior and interior parts for OA equipment and home electric appliances such as personal computers, notebook personal computers, laser beam printers, ink jet printers, copiers and facsimiles. In these application fields, great importance may be attached to the dyeing properties of a resin composition when it is mixed with a colorant, which are reflected on the gloss, color, clarity, uniformity and the like of a molded article. Also importance may be attached to the clarity of a character or mark printed by laser marking as a high-speed simple method for marking a desired character, symbol or pattern on the surface of a molded article at a high reproducibility.
Meanwhile, aromatic polycarbonate resin molded articles are used in a wide variety of industrial fields which require excellent transparency and heat resistance. Especially in application fields which require high transparency, such as lighting covers and protective covers for transmission type displays, they are widely used, making use of the excellent transparency, that is, high light transmission and extremely low haze of aromatic polycarbonate resins. In these application fields, resin materials are required to retain transparency, color and mechanical properties even when they are exposed to heat and humidity because a light source such as a fluorescent light or electric bulb becomes very hot or a product obtained therefrom is exposed to high humidity when it is used in a bath room or outside. Therefore, there is a case where great importance is attached to the resistance to moist heat of a resin composition, in addition to transparency.
In the above application fields, flame retardancy at the time of a fire has been attracting much attention and a resin composition having high flame retardancy in addition to the above characteristic properties is now desired. As means of providing flame retardancy to an aromatic polycarbonate resin or alloy thereof, flame retardant aromatic polycarbonate resin compositions which comprise a halogen compound such as a bromine compound or chlorine compound, or phosphorus compound as a flame retardant have been proposed and used in OA equipment and home electric appliances which are strongly desired to be flame retardant. Meanwhile, new flame retardant aromatic polycarbonate resin compositions have been developed as substitutes for the above resin compositions and are now being used in the above products. The purpose of changing the flame retardant is to suppress the generation of corrosive gas at the time of molding or improve the recyclability of products.
Flame retardants which are substitutes for the above flame retardant include a silicone compound. A flame retardant resin composition obtained by mixing a silicone compound with an aromatic polycarbonate resin has been studied vigorously and various proposals have been made.
For example, a method of mixing an alkali (earth) metal salt of perfluoroalkanesulfonic acid and an organic siloxane having an alkoxy group, vinyl group and phenyl group with a polycarbonate resin (JP-A 6-306265) (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and a method of mixing an alkali metal salt or alkali earth metal salt of perfluoroalkanesulfonic acid and an organopolysiloxane having an organoxysilyl group of which a silicon atom bonds to a divalent hydrocarbon group with a polycarbonate resin (JP-A 6-336547) have been proposed.
A method of mixing a specific petroleum-based heavy oil or pitch and a silicone compound with a resin component (JP-A 9-169914) and a method of mixing a silicone resin comprising a unit represented by R
2
SiO
1.0
and a unit represented by RSiO
1.5
and having a weight average molecular weight of 10,000 to 270,000 with a non-silicone resin having an aromatic ring (JP-A 10-139964) have also been proposed.
However, it cannot be said that the above proposed polycarbonate resin compositions are satisfactory in terms of transparency, resistance to moist heat and flame retardancy. For instance, when a molded article of the polycarbonate resin composition is thin, the UL 94 V-0 rank cannot be achieved due to the occurrence of dripping, a molded article thereof becomes cloudy due to the unsatisfactory dispersion of silicone, or transparency lowers after a moist heat treatment because silicone is agglomerated by the moist heat treatment.
Meanwhile, JP-B 60-38419 (the term “JP-B” as used herein means an “examined Japanese patent publication”) discloses a resin composition which comprises an aromatic polycarbonate resin, an organic alkali metal salt and poly(methyl hydrogensiloxane). However, it cannot be said that the resin composition is satisfactory in dyeing properties when it is mixed with a colorant, which are reflected on the gloss, color, clarity, uniformity and the like of a molded article because the composition itself becomes cloudy and a dispersion failure such as peeling occurs on the surface of the molded article.
Further, polytetrafluoroethylene having fibril forming capability is often used as a dripping preventing agent. However, when polytetrafluoroethylene is mixed with an aromatic polycarbonate resin, the transparency of the obtained molded article lowers because polytetrafluoroethylene and the aromatic polycarbonate resin are incompatible with each other.
Problems to be Solved by the Invention
It is a first object of the present invention to provide a flame retardant aromatic polycarbonate resin composition which comprises substantially no halogen compound and also preferably no phosphorus compound as a flame retardant. More specifically, it is a flame retardant aromatic polycarbonate resin composition which is excellent in dyeing properties at the time of coloring, the clarity of a character or mark printed by laser marking, and resin dripping preventing properties at the time of combustion.
It is a second object of the present invention to provide a transparent flame retardant aromatic polycarbonate resin composition which has excellent transparency, resistance to moist heat and resin dripping preventing properties at the time of combustion.
It is a third object of the present invention to provide a flame retardant aromatic polycarbonate resin composition which has excellent tracking resistance, antistatic properties and resin dripping preventing properties at the time of combustion.
Means for Solving the Problems
The inventors of the present invention have conducted intensive studies to attain the above objects and have found that a flame retardant aromatic polycarbonate resin composition which is excellent in dyeing properties at the time of coloring, the clarity of a character or mark printed by laser marking and resin dripping preventing properties at the time of combustion and further a flame retardant aromatic polycarbonate resin composition which has excellent transparency and resistance to moist heat are obtained by mixing a predetermined amount of a specif
Itagaki Akinari
Kobayashi Yoshiteru
Ono Tetsushi
Yamaya Masaaki
Sanders Kriellion A.
Teijin Chemicals Ltd.
Wenderoth, Lind&Ponack,LLP
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