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
2001-08-23
2004-03-02
Yoon, Tae H. (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...
C524S492000, C524S588000, C525S100000
Reexamination Certificate
active
06699925
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a flame-retardant thermoplastic resin composition and a manufacturing method thereof, and more particularly to a flame-retardant thermoplastic resin composition having excellent flame retardance and mechanical characteristics and to a manufacturing method thereof.
BACKGROUND OF THE INVENTION
Admixing compounds having halogen atoms typified by chlorine atoms into polyolefin-based resins is used as a method for imparting flame retardance to polyethylene resins, ethylene-vinyl acetate copolymer resins, and other olefin-based resins. Polyolefin-based resin compositions containing compounds that have halogen atoms are disadvantageous, however, in that large amounts of black smoke are produced during burning and biologically toxic gases or metal-corroding gases are also produced. In conventional practice, adding metal hydroxides such as aluminum hydroxide powders or magnesium hydroxide powders to polyolefin-based resins has been suggested as a means of addressing these problems. A drawback of this method, however, is that large amounts of metal hydroxides must be added in order to render polyolefin-based resins flame-retardant, and this yields flame-retardant polyolefin-based resins that have inferior molding properties and mechanical strength.
According to another method, metal oxides, phosphoric acid esters, and branched polyorganosiloxanes containing alkoxy groups are added to styrene-based resins, polyolefin-based resins, and other thermoplastic resins to obtain flame-retardant thermoplastic resin compositions (JP Patent Application Publication(Kokai) Hei5-339510). However, a flame-retardant thermoplastic resin composition obtained by this method does not necessarily have adequate flame retardance and requires the use of phosphoric acid esters when the method is employed, creating concern that, for example, the soil will be contaminated by phosphorus compounds when the resin is discarded.
As a result of thoroughgoing research aimed at addressing these problems, the inventors perfected the present invention upon discovering that flame retardance can be markedly improved by admixing a condensation reaction promoting catalyst and two specific types of branched polyorganosiloxanes into a thermoplastic resin. Specifically, an object of the present invention is to provide a thermoplastic resin composition having excellent flame retardance and to provide a method for manufacturing this resin.
SUMMARY OF THE INVENTION
The present invention relates to a flame-retardant thermoplastic resin composition comprising (A) 100 weight parts of a thermoplastic resin, (B) 10 to 300 weight parts of particulate metal hydroxide; (C) 0.01 to 50 weight parts of a branched polyorganosiloxane having alkoxy groups and described by average unit formula R
1
a
(R
2
O)
b
SiO
(4−a−b)/2
, where R
1
and R
2
are monovalent hydrocarbon groups selected from the group consisting of alkyl, alkenyl, and aryl groups, a is 0 or a positive number; b is a positive number; and a+b is a number from 0.75 to 2.5; (D) 0.01 to 50 weight parts of a branched polyorganosiloxane having silanol groups and described by average unit formula R
3
a
(HO)
b
SiO
(4−a−b)/2
, where R
3
is a monovalent hydrocarbon group selected from the group consisting of alkyl, alkenyl, and aryl groups, a is 0 or a positive number, b is a positive number, and a+b is a number from 0.75 to 2.5; and (E) 0.01 to 10 weight parts of a condensation reaction promoting catalyst. The present invention further relates to a method for manufacturing the above described flame-retardant thermoplastic resin composition.
DESCRIPTION OF THE INVENTION
The present invention relates to a flame-retardant thermoplastic resin composition comprising (A) 100 weight parts of a thermoplastic resin, (B) 10 to 300 weight parts of particulate metal hydroxide; (C) 0.01 to 50 weight parts of a branched polyorganosiloxane having alkoxy groups and described by average unit formula R
1
a
(R
2
O)
b
SiO
(4−a−b)/2
, where R
1
and R
2
are monovalent hydrocarbon groups selected from the group consisting of alkyl, alkenyl, and aryl groups, a is 0 or a positive number; b is a positive number; and a+b is a number from 0.75 to 2.5; (D) 0.01 to 50 weight parts of a branched polyorganosiloxane having silanol groups and described by average unit formula R
3
a
(HO)
b
SiO
(4−a−b)/2
, where R
3
is a monovalent hydrocarbon group selected from the group consisting of alkyl, alkenyl, and aryl groups, a is 0 or a positive number, b is a positive number, and a +b is a number from 0.75 to 2.5; and (E) 0.01 to 10 weight parts of a condensation reaction promoting catalyst. The present invention further relates to a method for manufacturing the above described flame-retardant thermoplastic resin composition.
The thermoplastic resin of component (A) is not subject to any particular limitations as long as it is an organic resin having thermoplastic properties (properties that characterize reversible changes in which deformation is impeded, elasticity is displayed, and plasticity is absent at normal temperature, but appropriate heating brings out plasticity and makes the resin moldable, whereas reducing the temperature by cooling returns the resin to its plastic state with only minimal chemical changes in the molecular structure or the like). Specific examples include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and copolymers of ethylene with propylene, butene-1, pentene-1, hexene-1,4-methylpentene-1, octene-1, decene-1, and other C
3
-C
12
&agr;-olefins; polypropylene and copolymers of propylene with ethylene, butene-1, pentene-1, hexene-1,4-methylpentene-1, octene-1, decene-1, and other C
3
-C
12
&agr;-olefins; polyolefin resins such as ethylene-propylene copolymers, ethylene-propylene-diene copolymers, copolymers of ethylene with vinyl-based monomers (vinyl acetate, ethyl acrylate, methacrylic acid, ethyl methacrylate, maleic acid, maleic anhydride, and the like), and copolymers obtained by modifying ethylene homopolymers or copolymers of ethylene and &agr;-olefins with acrylic acid, maleic acid, or other unsaturated carboxylic acids or derivatives thereof; aromatic polycarbonate resins and copolymers thereof; polyphenylene ether resins and copolymers thereof; polyarylate resins; polyethylene terephthalate resins, polybutylene terephthalate resins and other aromatic polyester resins; polyamide resins; and polystyrene resins, polystyrene resins, ABS resins, AS resins, and other styrene-based resins. Of these, the polyolefin-based resins are preferred.
The particulate metal hydroxide of component (B) acts to provide the inventive composition with flame retardance. Component (B), which is a hydroxide of Group Ia, IIIa, or IVb metal of the Periodic Table, has a decomposition start temperature of 150 to 450° C. Specific examples include particulate magnesium hydroxide, particulate aluminum hydroxide, and products obtained by treating the surfaces of these compounds with silane coupling agents, titanium coupling agents, higher fatty acids, and other surface treatment agents. Of these, particulate magnesium hydroxide is preferred. The mean particle size should be between 0.01 and 30 &mgr;m, and preferably 0.05 and 10 &mgr;m, in order to provide the thermoplastic resin with adequate dispersibility and to prevent the molding properties of the resin composition from being adversely affected.
Component (B) should be added in an amount of 1 to 300 weight parts, and preferably 50 to 150 weight parts, per 100 weight parts of component (A), because adding too little of the component is ineffective for imparting flame retardance, while adding too much of component (B) has an adverse effect on mechanical strength.
By being used together with a branched polyorganosiloxane containing silanol groups (component (D)), the branched polyorganosiloxane containing alkoxy groups (component (C)) improves the flame retardance of component (A). Component (C) is a branched polyo
Furukawa Haruhiko
Hatanaka Hidekatsu
Morita Yoshitsugu
Nakanishi Koji
Shiromoto Koji
Dow Corning Toray Silicone Co. Ltd.
Yoon Tae H.
Zombeck Alan
LandOfFree
Flame-retardant thermoplastic resin composition and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flame-retardant thermoplastic resin composition and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flame-retardant thermoplastic resin composition and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3217656