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
2000-02-04
2003-09-02
Cain, Edward J. (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...
C454S187000
Reexamination Certificate
active
06613835
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a wet-type sealing material (room temperature curable liquid), a building component made of polyvinyl chloride for use in a clean room used, for example, in factories or research laboratories in the field of semiconductors, foodstuffs, medicines and biotechnology, a clean room, and a local facility through which clean air is taken into the clean room.
2. Related Art Statement
In a clean room used, for example, in factories or research laboratories in the field of semiconductors, foodstuffs, medicines and biotechnology, dry air filters for trapping particulate substances suspended in air are disposed to an air introduction path and air after passing therethrough is introduced into the room. As the degree of integration of semiconductors has been increased recently, not only dusts but also diffusion of organic gases in air in the clean room have caused such a problem as follows.
It has been pointed out that organic gases are adsorbed on the surface of silicon wafers under processing for semiconductor devices in a clean room may deteriorate their characteristics (for example, Fujii, “Gaseous Contaminants and Current Situation for Countermeasure of Removing Them”, Air Cleaning (Kuki Senjo), Vol. 32, No. 3, p 43 (1994), published from the Foundation of Japan Air Cleaning Society).
OBJECT OF THE INVENTION
The present invention has been accomplished for overcoming such a problem and it is an object thereof to provide a dry-type sealing material such as a gasket used upon mounting an air filter, for example, to an opening of a ceiling, which can eliminate the presence of gaseous organic materials in a clean room, a method of manufacturing the dry-type sealing material, as well as a clean room and a local facility using the same.
It is another object of the present invention to provide a wet-type sealing material used, for example, for connecting wall materials or partitioning materials, which can eliminate the presence of gaseous organic materials in a clean room, a method of manufacturing the wet-type sealing material, as well as a clean room and a local facility using the same.
It is a further object of the present invention to provide a building component made of vinyl chloride (for example, a vinyl chloride sheet covering the surface of a floor or a vinyl cloth covering the surface of a wall), which can eliminate the presence of gaseous organic materials in a clean room, a method of manufacturing the building component and a clean room using the same.
SUMMARY OF THE INVENTION
The present inventors, et al have made earnest studies for attaining the foregoing objects and have found that one of the reasons for the presence of gaseous organic materials in a clean room is attributable to a dry-type sealing material such as a gasket which is disposed for mounting an air filter to an opening of a ceiling or the like and a packing used for connecting wall materials or partitioning materials. That is, it has been found by the study of the present inventors, et al that the existent dry-type sealing materials described above release gaseous organic materials such as carboxylic acid esters, phosphoric acid esters and phenols.
Specifically, it has been found that the existent dry-type sealing materials contain liquid paraffin (aliphatic hydrocarbons of 12 to 18 carbon atoms) as a lubricant, and also contains a plasticizer and an antioxidant of relatively low molecular weight.
In a first aspect according to the present invention, there is provided a dry-type sealing material formed by molding a mixture of a raw material rubber and formulations into a predetermined shape, in which at least one of the raw material rubber and the formulations does not release gaseous organic materials.
In a preferred embodiment of the dry-type sealing material of the first aspect according to the present invention, the raw material rubber is at least one of urethane rubber, butyl rubber, ethylene propylene rubber, ethylene propylene terpolymer rubber, isoprene rubber, acrylic rubber, vinyl chloride rubber, chloroprene rubber and fluoro rubber. The raw material rubbers described above do not release gaseous organic materials. The urethane rubber used herein should not contain organic phosphoric acid compounds. The ethylene propylene terpolymer rubber is a rubber comprising a ternary copolymer of ethylene, propylene and a third ingredient.
In another embodiment of the dry-type sealing material of the first aspect according to the present invention, a main ingredient of a lubricant in the formulations is at least one of aliphatic hydrocarbons of not less than 20 carbon atoms and higher alcohols of not less than 18 carbon atoms.
In a further embodiment of the dry-type sealing material of the first aspect according to the present invention, the main ingredient of the lubricant is at least one of microcrystalline wax, natural paraffin, synthetic paraffin, polyolefin wax, branched alcohols of 18, 20 or 24 carbon atoms and oleyl alcohol.
If the main ingredient of the lubricant is an aliphatic hydrocarbon of not more than 19 carbon atoms or a higher alcohol of not more than 17 carbon atoms, gaseous organic materials are present in air in a clean room which is controlled to a temperature of 23° C. and a humidity of 30 to 40% and in which the flow rate of air passing through an air filter is about 0.3 to 0.4 m/s. However, when an aliphatic hydrocarbon of not less than 20 carbon atoms or a higher alcohol of not less than 18 carbon atoms, for example, the above mentioned embodiment is used, such gaseous materials are not present in air in the clean room.
In a further embodiment of the dry-type sealing material of the first aspect according to the present invention, a main ingredient of a plasticizer in the formulations is at least one of carboxylic acid esters, polyesters and epoxy series compounds having a molecular weight of not less than 400.
In the above-mentioned embodiment, the main ingredient of the plasticizer is preferably at least one of the following materials (a):
(a) Isononyl phthalate (molecular weight: 418), octyldecyl phthalate (molecular weight: 419), diisodecyl phthalate (molecular weight: 447), lauryl phthalate. (molecular weight: 501), myristylyl phthalate (molecular weight: 530), di-2-ethylhexyl azelate (molecular weight: 413), di-2-ethylhexyl sebacate (molecular weight: 427), tris-2-ethylhexyl trimellitate (molecular weight: 547), trioctyl trimellitate (molecular weight: 547), trinonyl trimellitate (molecular weight: 570), tridecyl trimellitate (molecular weight: 612), polyester obtained by polycondensation of adipic acid, azelaic acid, sebacic acid or phthalic acid with glycol or glycerine (molecular weight: 2000-8000), epoxy fatty acid ester (molecular weight: 400-500) and epoxidized oil (molecular weight: 1000).
In the above-mentioned further embodiments of the dry-type sealing material of the first aspect according to the present invention, the raw material rubber contains chlorine atoms in the chemical structure, and the main ingredient of the plasticizer in the formulations is chlorinated paraffin having a molecular weight of not less than 400.
If the main ingredient of the plasticizer is dibutyl phthalate (molecular weight: 278), dioctyl phthalate (molecular weight: 391) or di-2-ethylhexyl adipate (molecular weight: 371), gaseous materials of them are present in air in a clean room. However, when those having a molecular weight of not less than 400, for example, as described in the aforementioned embodiments, such gaseous materials are not present in air in the clean room.
In a further embodiment of the dry-type sealing material of the first aspect according to the present invention, a main ingredient of an antioxidant in the formulations is a phenolic compound having a molecular weight of not less than 300.
In the above-mentioned embodiment, the main ingredient of the antioxidant is preferably at least one of the following materials (b):
(b) stearyl-&bgr;-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (molecular weig
Imafuku Masayuki
Kobayashi Sadao
Wakayama Yoshihide
Cain Edward J.
Taisei Corporation
Young & Basile P.C.
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