Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-10-11
2003-08-05
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S158000, C524S160000, C524S161000, C524S267000, C524S268000, C524S269000, C525S464000
Reexamination Certificate
active
06602938
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a fire-resistant polycarbonate resin composite. More specifically, it is related to a fire-resistant polycarbonate resin composite having improved fire retarding properties not containing halogen, i.e., chlorine and bromine, or flame-retarding agents, without impairing mechanical properties such as excellent shock resistance, fluidity and appearance of molded components which are characteristic of polycarbonate resins.
BACKGROUND OF THE INVENTION
Polycarbonate resins are widely used in many fields, such as the electrical, electronic and OA fields, as engineering plastics having excellent transparency, shock resistance, heat resisting properties and electrical properties.
In the electrical, electronic and OA fields, many components are required to have superior fire retarding properties (UL94V) and advanced shock resistance, such as personal computer exterior parts. A polycarbonate resin is a highly fire-resistant plastic having self-extinguishing properties, but in order that it may satisfy safety requirements for electrical, electronic and OA equipment, still higher fire retarding properties equivalent to UL94V-0 or 94V-1 are needed.
Thus, to improve the fire retarding properties of a polycarbonate resin, a method has conventionally been used of blending it with a large amount of an oligomer or polymer of a carbonate derivative of brominated bisphenol A. However, although the fire retarding properties of a polycarbonate resin definitely improved when it was blended with a large amount of an oligomer or polymer of a carbonate derivative of brominated bisphenol A as a flame retarder, the shock resistance fell, and cracks easily developed in molded components.
Also, as it was mixed with a large amount of a halogen compound containing bromine, there was a concern that gas containing the halogen would be generated at the time of combustion, so a flame-retarding agent not containing chlorine or bromine was desired from the environmental viewpoint. Silicone compounds have high heat resistance, do not easily generate harmful gases during combustion and are also inherently safe, so many attempts have been made to use them as flame retarders.
Silicone compounds which are flame retarders are polymers comprising at least the four siloxane units (M unit, D unit, T unit, Q unit) shown below.
(1) M unit
Structure
Chemical formula R
3
SiO
0.5
where, R is an organic substituent.
(2) D Unit
Structure
Chemical formula R
2
SiO
1.0
where, R is an organic substituent.
(3) T Unit
R
Structure
Chemical formula RSiO1.5 where, R is an organic substituent.
(4) Q Unit
Structure
Chemical formula RSiO2.0
Of these, the structure will be a branched structure if it contains a T unit and/or a Q unit.
Regarding the use of silicone compounds as flame retarders, silicone compounds with various organic substituents have been studied as disclosed in JP, 1-318069 (Kokai), and JP, 62-60421 (Kokoku).
However, there are very few compounds which conferred a significant flame-retarding effect when added alone, and as a large amount had to be added to satisfy the stringent requirements of electrical and electronic equipment, it had an adverse effect on the moldability and kneadibility of the plastic or other necessary characteristics. Since it was disadvantageous also from the cost viewpoint, it was also impractical.
In an attempt to improve the flame-retarding effect of the silicone compound and reduce the addition amount, the use of a silicone compound in conjunction with a metal salt has also been reported. In this regard, the combined use of polydimethyl silicone, metal hydroxide and a zinc compound (JP, 2-150436 (Kokai)), polydimethyl silicone with a group IIa metal salt of an organic acid (JP, 56-100853 (Kokai)), a silicone resin, especially as represented by an M unit and a Q unit, with a silicone oil and a group Iha metal salt of an organic acid (JP, 3-48947 (Kokoku)), may be mentioned, but all are inferior in respect of fire retarding properties. There was a fundamental problem in that drastic curtailment of the addition amount was difficult.
The combined use of an organopolysiloxane having an epoxy group (gamma-glycidoxypropyl group), phenyl group and/or vinyl group together with an alkali metal salt and alkaline earth metal salt, etc. of an organic sulfonic acid (JP, 8-176425 (Kokai)) has also been reported. However, as this silicone compound contains highly reactive epoxy groups and vinyl groups, the silicone compounds react with each other at the elevated temperature during kneading with the polycarbonate resin, causing polymerization (gelation), so that it is difficult to knead it uniformly with the polycarbonate resin. Moreover, the overall viscosity also rises, so peeling, molding sink and unevenness in the moldability of the polycarbonate resin, and particularly the surface of the molded body, occur. Further, due to this gelation, the dispersibility of the silicone compound in the polycarbonate resin is inadequate, consequently it is difficult to achieve a significant fire resistance, and there is also a problem in that strength properties, such as the impact strength of the molded product, also decrease.
DISCLOSURE OF THE INVENTION
As a result of extensive research on the aforesaid problems, the Inventors discovered that a fire-resistant polycarbonate resin composite having superior fire retarding properties could be obtained without compromising shock resistance and moldability by using a specific silicone compound and an alkali metal salt of a specific aromatic sulfonic acid, with the further addition of a fiber-forming fluorine-containing polymer, as a flame retarder blended with the polycarbonate resin.
Moreover, since the fire-resistant polycarbonate resin composite of this invention does not contain halogen flame retarders, such as a bromine flame retarder, there is also no concern regarding the generation of gas containing halogen from the halogen flame retarder during combustion, and it also has excellent performance from the viewpoint of environmental protection.
Specifically, this invention relates to a fire-resistant polycarbonate resin composite comprising 0.01-8 weight parts of a silicone compound (B) having a branch structure in the main chain and an aromatic group in the organic substituents contained therein, and 0.01-2 weight parts of an alkali metal salt of an aromatic sulfonic acid represented by the following general formula 1, relative to 100 weight parts of a polycarbonate resin (A), and further containing a fiber-forming fluorine-containing polymer (D) in the composition.
A
m
—R—(SO
3
M)
n
General formula 1
(where R is phenyl naphthyl, or phenyl or naphthyl substituted by A, where A is chosen from a halogen atom, alkyl group, arl group, vinyl group, alkoxy group, amino group, methyl ester group and ethyl ester group, and M is an alkali metal. Moreover, when R is a phenyl group, m and n are respectively integers of 0-5 and 1-2, (m+n≦6) and when R is a naphthyl group, m and n are respectively 0-7 and 1-2 (m+n≦8).
Below, the fire-resistant polycarbonate resin composite of this invention will be described in detail.
The polycarbonate resin (A) used for this invention is a polymer obtained by the phosgene method wherein various dihydroxydiaryl compounds and phosgene are made to react, or the ester exchange method wherein a dihydroxydiaryl compound and a carbonic acid ester such as diphenyl carbonate, are made to react, a specific example being the polycarbonate resin manufactured from 2,2-bis(4-hydroxy phenyl)propane (bisphenol A).
The above-mentioned dihydroxydiaryl compound, in addition to bisphenol A, may be a bis (hydroxyaryl) alkane such as bis(4-hydroxy phenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy phenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methyl phenyl)propane, 1,1-bis (4-hydroxy-3-t-butyl phenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane
Iji Masatoshi
Sato Ichiro
Serizawa Shin
Shinomiya Tadashi
Umeyama Satoshi
Buttner David J.
Gary C Cohn PLLC
Sumitomo Dow Ltd.
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