Coating processes – Heat decomposition of applied coating or base material – Base material decomposed or carbonized
Reexamination Certificate
2000-06-02
2001-03-27
Fiorilla, Christopher A. (Department: 1731)
Coating processes
Heat decomposition of applied coating or base material
Base material decomposed or carbonized
C264S624000, C427S226000, C427S228000
Reexamination Certificate
active
06207230
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of preparing a high-heat-resistance resin composite ceramic containing a heat-resistant silicone-containing resin, which high-heat-resistance resin composite ceramic can be used at a high temperature of over 400° C. and can be therefore used as a raw material or auxiliary material for use as a product to be exposed to such a high temperature or for use in the steps of producing electronic parts to be used at such a high temperature.
PRIOR ART OF THE INVENTION
Ceramics have excellent properties such as a low heat expansion coefficient, a high heat-radiating property, electric insulation, and the like. These excellent physical properties are relied upon to commercialize various products such as a printed wiring board, and the like.
Since, however, ceramics are generally poor in processability, it is required to employ special machines and equipment and high processing techniques for applying them to desired products such as parts, so the products are expensive and are therefore limited in use.
For compensating the above defects with machinability, machinable ceramics have been developed. However, the machinable ceramics are fragile, and the machinability of these ceramics is limited. Further, the machinable ceramics are prepared by compositing and have pores, which results in a defect that they show a large change in physical properties due to moisture absorption, and the like.
A C/C carbon composite is excellent in heat resistance and thermal expansion coefficient and is also excellent in processability. However, the defect with it is that it shows large water absorption when used alone, and that it is liable to cause carbon dust. While an amorphous carbon and a glassy carbon are considerably improved in these properties, these are not yet satisfactory in improvements.
The present inventors completed a method of preparing a substrate, in which the above defects such as water absorption can be overcome and a substrate having high thickness accuracy can be obtained by preparing a novel resin-impregnated ceramic improved in machiability and impart with impact resistance and cutting the ceramic (JP-A-5-291706, etc.). Further, as a result of further studies, there was completed a metal-foil-clad resin composite ceramic substrate obtained by bonding a metal foil to a resin-impregnated and -cured composite ceramic layer (JP-A-8-244163).
The above resin composite ceramic substrate has a low water absorption ratio and excellent durability against water and chemicals, and in these points, the resin composite ceramic overcomes all the defects of ceramics. However, the upper limit temperature of the heat durability thereof depends upon the heat resistance of a resin used, and those resins disclosed in the above prior techniques are greatly limited in use at a temperature of over 400° C. There is a limitation to be imposed on the use of the above substrate when it is exposed to a temperature of over 400° C.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of preparing a high-heat-resistance resin composite ceramic which has a low water absorption ratio and has excellent durability against water and chemicals and which shows excellent heat resistance.
It is another object of the present invention to provide a method of preparing a high-heat-resistance resin composite ceramic which has excellent durability against plasma and which exhibits “outgassing” to a less degree at a high temperature under high vacuum.
That is, according to the present invention, there is provided a method of preparing a high-heat-resistance resin composite ceramic, comprising the steps of impregnating an inorganic continuously porous sintered body (I) having an open porosity of at least 0.5% with an organometallic compound (M), heat-treating the impregnated inorganic continuously porous sintered body (I) to decompose the organometallic compound (M) and thereby forming a metal compound which is a carbide, a nitride, an oxide or a composite oxide on an inner wall plane of each of open pores, and
filling a heat-resistant silicone resin (R) in the open pores by impregnation under vacuum and thermally curing the heat-resistant silicone resin (R).
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the inorganic continuously porous sintered body (I) preferably has an open porosity of 2 to 35% and an average pore diameter in the range of from 0.1 to 10 &mgr;m. The inorganic continuously porous sintered body (I) is preferably selected from an aluminum nitride-boron nitride composite sintered body (AlN-h-BN), a silicon nitride-boron nitride sintered body (Si
3
N
4
-h-BN), a sintered body of a &bgr;-silicon carbide porous material (&bgr;-SiC) or a sintered body of a material shaped from carbon (C). The above inorganic continuously porous sintered body (I) is impregnated with an organometallic compound (M), and the impregnated inorganic continuously porous sintered body (I) is heat-treated preferably by treating it at a temperature equivalent to, or lower than, 300° C. in a preliminary treatment and then treating it at a maximum temperature of 850° C. or lower to decompose the organometallic compound (M). The organometallic compound (M) is preferably selected from an organometallic compound containing aluminum, titanium or silicon or an organometallic compound which is a prepolymer having a weight average molecular weight of less than 10,000.
The constitution of the present invention will be explained hereinafter.
The inorganic continuously porous sintered body (I) used in the present invention is a ceramic or a carbon having continuous pores and having the form of a flat plate, a disk, a cube, a rectangular parallelepiped, a cylinder or other. The inorganic continuously porous sintered body (I) preferably includes sintered bodies of an aluminum nitride-boron nitride composite material (AlN-h-BN), a silicon nitride-boron nitride composite material (Si
3
N
4
-h-BN), a &bgr;-silicon carbide porous material (&bgr;-SiC), titanated aluminum (TiN) and a shaped material of carbon (C). The shaped material of carbon (C) includes C/C carbon composite and others such as amorphous carbon and glassy carbon.
The heat-resistant silicone resin (R) used in the present invention can be any silicone resin so long as it can be easily viscosity-decreased in a state where it contains a solid content (resin content) to some extent. That is, even a silicone resin mostly equivalent to an oligomer can be used. Specifically, the heat-resistant silicone resin (R) includes a ladder silicone resin (polyorganosiloxane), polysilazane, polyimdesiloxane and polyorganosilsesquioxane-cyanate resin.
Of these, a ladder silicone resin is preferred. The ladder silicone resin includes one having methyl and phenyl groups as side chains, one having methyl groups alone as side chains and one having phenyl groups alone as side chains, and all of these ladder silicone resins have high heat resistance. The formula (1) to be described later shows a ladder silicone resin having methyl and phenyl groups as side chains.
For impregnating the inorganic continuously porous sintered body (I) with the heat-resistant silicone resin (R), it is required to improve the affinity between these two members. The affinity can be improved by impregnating open pores of the inorganic continuously porous sintered body (I) with an organometallic compound (M) which is an aluminum-, titanium- or silicon-containing compound or a prepolymer having a weight average molecular weight of less than 10,000, and pyrolyzing the organometallic compound to form a metallic compound which is an oxide or a composite oxide on an inner surface plane of each open pores.
The organometallic compound (M) includes aluminum chelates such as aluminum isopropylate, aluminum ethylate, aluminum sec-butylate, aluminum mono-sect-butoxydiisopropylate, aluminum isopropoxide, ethylacetoacetatealuminum diisopropylate, aluminum tris(ethylacetoacetate), and aluminum monoacetylacetonate-bis(ethylacetoacetate) and aluminum
Ohya Kazuyuki
Sayama Norio
Fiorilla Christopher A.
Mitsubishi Gas Chemical Company Inc.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Method of the preparation of high-heat-resistance resin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of the preparation of high-heat-resistance resin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of the preparation of high-heat-resistance resin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485491