Silsesquioxane polymer molding and method of preparing same

Details Silsesquioxane polymer molding and method of preparing same Silsesquioxane polymer molding and method of preparing same

2002-02-28

2004-08-10

Peng, Kuo-Liang (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S032000, C525S478000, C264S299000, C264S319000

Reexamination Certificate

active

06774200

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a molding of a heat-resisting silicon-containing organic polymer having siloxane bonds and to a method of preparing same.
Various types of heat-resisting, silicone-type silicon-containing resins are known such as a silicone resin which is a sort of silsesquioxane polymers. Such silicone resins are used as a coating material, a binder for powder, a sealing agent, a resist material, an electrically insulating material, a paint or a primer. It is, however, difficult to produce a molding of such silicone resins.
The present inventors disclose in JP-A-2000-154252 (Japanese patent No. 2,979,145) a hydrosilylated polymer obtained by reacting octakis(hydridosilsesquioxane), namely pentacyclo-[9.5.1.1
3,9
.1
5,15
.1
7,13
]ocatasiloxane, which is one of a cage-type hydridosilsesquioxanes, with a divinylsiloxane of the formula CH
2
═CH—Si(CH
3
)
2
—O—Si(CH
3
)
2
—CH═CH
2
. This polymer, which is soluble in organic solvents and has a melting point, gives residues in an amount of 89.3% of the original weight when heated to 984° C. in the atmosphere of nitrogen at a heating rate of 10° C. per minutes. In this case, the temperature T
d5
at which the original weight decreases by 5% is 595° C. When heated in air to 983° C. at a heating rate of 10° C. per minutes, the polymer leaves residues in an amount of 92.4% of the original weight. The T
d5
is 569° C. Thus, the polymer has excellent heat resistance and excellent fire resistance.
U.S. Pat. No. 6,252,030 discloses a hydrogenated octasilsesquioxane-vinyl group-containing compound copolymer which is soluble in organic solvents and useful as an insulating material. It is described that the SiH functionality at the corners of the cage structure of the copolymer form siloxane bonds with the SiH functionality of other cage structure corners when the copolymer is heated, allowed to stand, or otherwise handled after being applied to the required area in a mode of coating, packing, molding, or the like and that the copolymer can be used to construct a three-dimensionally reticulated structure, creating a cover film, layer, molded article, or interlayer insulation material with excellent mechanical properties and improved stability, heat resistance, oxidation resistance, and insulation characteristics. However, only specifically disclosed in the U.S. patent is the formation of coatings by using a spin coating method. Further, the U.S. patent describes that the copolymer will have adequate storage stability if stored so that it does not come into contact with water and that, after the copolymer has been applied by coating, dipping, or another such means, it absorbs the moisture in the air (and is heated if needed), which promotes crosslinking and curing, resulting in a layer and coating film having the necessary mechanical and electrical insulating characteristics. Thus, the U.S. patent is silent with respect to a method of preparing moldings using the copolymer.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above state of the art.
It is an object of the present invention to provide an insoluble and infusible molding of a silsesquioxane polymer using a hydrosilylated polymer.
Another object of the present invention is to provide a method which can prepare the above molding in a simple manner.
In accordance with the present invention there is provided a molding obtained by heating a hydrosilylated polymer at a temperature higher than the softening point or melting point thereof, said hydrosilylated polymer being obtained by reacting at least one hydridosilsesquioxane compound of the following formula (1):
(HSiO
3/2
)
n
  (1)
wherein n is an integer of 4-1000, with at least one divinylsiloxane compound of the following formula (2):
CH
2
═CH—SiR
2
—O—(SiR
2
.O)
q
—(SiR′
2
.O)
q′
—SiR
2
—CH═CH
2
  (2)
wherein R and R′ are independently selected from alkyl groups, substituted alkyl groups, aryl groups and substituted aryl groups, and q and q′ are each an integer of 0 or more.
In another aspect, the present invention provides a method of preparing a molding, comprising the steps of:
(a) providing a hydrosilylated polymer obtained by reacting at least one hydridosilsesquioxane compound of the following formula (1):
(HSiO
3/2
)
n
  (1)
wherein n is an integer of 4-1000, with at least one divinylsiloxane compound of the following formula (2):
CH
2
═CH—SiR
2
—O—(SiR
2
.O)
q
—(SiR′
2
.O)
q′
—SiR
2
—CH═CH
2
  (2)
wherein R and R′ are independently selected from alkyl groups, substituted alkyl groups, aryl groups and substituted aryl groups, and q and q′ are each an integer of 0 or more, and
(b) heating said hydrosilylated polymer at a temperature higher than the softening point or melting point thereof.
Other objects, features and advantages of the present invention will become apparent from the detailed description of the preferred embodiments of the invention to follow.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
A silicon-containing polymer molding according to the present invention is prepared from a hydrosilylated polymer which is obtained by reacting at least one hydridosilsesquioxane compound of the following formula (1):
(HSiO
3/2
)
n
  (1)
wherein n is an integer of 4-1000, with at least one divinylsiloxane compound of the following formula (2):
CH
2
═CH—SiR
2
—O—(SiR
2
.O)
q
—(SiR′
2
.O)
q′
—SiR
2
—CH═CH
2
  (2)
wherein R and R′ are independently selected from alkyl groups, substituted alkyl groups, aryl groups and substituted aryl groups, and q and q′ are each an integer of 0 or more. The hydrosilylated polymer is soluble in organic solvents and has excellent heat resistance, excellent chemical resistance, excellent electrically insulating properties and excellent mechanical properties such as strengths and toughness.
The hydridosilsesquioxane compound of the above formula (1) may be, for example, octakis-(hydridosilsesquioxane), decakis(hydridosilsesquioxane), dodecakis(hydridosilsesquioxane) or a hydridosilsesquioxane oligomer. Octakis-(hydridosilsesquioxane) is preferably used for the purpose of the present invention. These hydridosilsesquioxane compounds may be used singly or as a mixture of two or more.
In the above formula (2) representing the divinylsiloxane compound, R and R′ may be, for example, an alkyl group such as methyl, ethyl, isopropyl, tert-butyl or hexyl, or an aryl group such as phenyl, tolyl, anisyl or naphthyl. The alkyl may have one or more substituents such as aryl and alkoxy, while the aryl group may have one or more substituents such as alkyl and alkoxy. The alkyl and aryl groups of R and R′ may have other substituents which are inert to the hydrosilylation reaction of the compounds of the formulas (1) and (2).
Specific examples of divinylsiloxane compounds include 1,3-divinyltetramethyldisiloxane, 1,5-divinylhexamethyltrisiloxane, 1,7-divinyloctamethyltetrasiloxane, &agr;,&ohgr;)-divinylpoly(dimethylsiloxane), 1,3-divinyltetraphenyldisiloxane, 1,5-divinylhexaphenyltrisiloxane, 1,7-divinyloctaphenyltetrasiloxane, &agr;,&ohgr;-divinylpoly(diphenylsiloxane), vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymers. These divinylsiloxanes may be used singly or as a mixture of two or more.
The reaction of the hydridosilsesquioxane compound of the above formula (1) with the divinylsiloxane compound of the above formula (2) is generally carried out in the presence of a customarily employed catalyst such as a platinum-containing catalyst.
Specific examples of the platinum-containing catalyst include platinum divinyltetramethyldisiloxane, platinum cyclic vinylmethylsiloxane, tris(dibenzylideneactone)diplatinum, chloroplatinic acid, bis(ethylene)tetrachlorodiplatinum, cyclooctadienedichloroplatinum, bis(cyclooctadiene)platinum, bis(dimethylphenylphosphine)dichloroplatinum, tetrakis(triphenylphosphite)platinum and platinum carbon

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