Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-07-05
2003-10-21
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S280000
Reexamination Certificate
active
06635717
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a molding material and crosslinkable molding composition which comprise a fluorine-containing multi-segment polymer and used suitably for molding of various molded articles demanded to have a sealing property and cleanliness, and relates to various molded articles produced therefrom by molding, particularly a sealing material and semiconductor-related production apparatuses provided with the sealing material.
BACKGROUND ART
Fluorine-containing elastomers have excellent heat resistance, oil resistance, chemical resistance, etc. and are widely used in various fields, for example, in the fields of electrical and electronic industries, transportation, chemical industries, machinery, foods and metals as molding materials for a sealing material, O-ring, gasket, oil seal, diaphragm, hose, roll, belt, packing and the like.
For example, in the field of production of semiconductors, contamination in a production process is required to be eliminated as much as possible, and there was proposed an attempt to inhibit elution of metal and enhance a strength by adding a fluorine-containing resin fine powder to a fluorine-containing elastomer comprising fluoroolefin and perfluoro(alkyl vinyl ether) (WO97/08239). However since a fluorine-containing resin fine powder is simply kneaded physically, a fluorine-containing resin is released during use, which causes particles as a foreign matter, lowers gas impermeability and results in insufficient cleanliness and sealing property.
Also a fluorine-containing multi-segment polymer prepared by block-copolymerizing an elastomeric fluorine-containing polymer chain segment with a non-elastomeric fluorine-containing polymer chain segment is known.
JP-A-7-316246 discloses various combinations of components (monomers) constituting a fluorine-containing multi-segment polymer. However a concrete example disclosed therein is only a fluorine-containing multi-segment polymer prepared by block-copolymerizing an elastomeric fluorine-containing polymer chain segment comprising vinylidene fluoride (VdF)/hexafluoropropylene (HFP)/tetrafluoroethylene (TFE) with a non-elastomeric fluorine-containing polymer chain segment comprising polyvinylidene fluoride (PVdF).
JP-A-6-220143 discloses various combinations of components (monomers) constituting a fluorine-containing multi-segment polymer. However concrete examples disclosed therein are only combinations of TFE/propylene, TFE/propylene/VdF and TFE/hydrocarbon type olefin of C2 or C3/perfluoro(alkyl vinyl ether) (PAVE) as an elastomeric fluorine-containing polymer chain segment and PTFE, TFE/ethylene and TFE/PAVE as a non-elastomeric fluorine-containing polymer chain segment.
However those fluorine-containing multi-segment polymers are low in a blocking ratio and contain many polymer molecules comprising only elastomeric fluorine-containing polymer chain segment, to which a non-elastomeric component is not bonded. Therefore in various molded articles produced by molding them, elution of elastomeric fluorine-containing polymer chain segment and other low molecular weight substances occurs and thus heat resistance, chemical resistance and mechanical properties are insufficient. Particularly in case of use as a sealing material for semi-conductor device production apparatuses, in which cleanliness is demanded, there arises a problem with elution of elastomeric fluorine-containing polymer chain segment and other low molecular weight substances due to a low blocking ratio. Also the polymer itself is colored milky white, and transparency which is a characteristic of a fluorine-containing multi-segment polymer is deteriorated.
An object of the present invention is to provide the material for molding, i.e. the molding material and crosslinkable molding composition which comprise a fluorine-containing multi-segment polymer having an elastomeric fluorine-containing polymer chain segment and a non-elastomeric fluorine-containing polymer chain segment, particularly a sealing material for semiconductor-related production apparatuses which is produced by molding the molding material and crosslinkable molding composition and ensures less elution of elastomeric fluorine-containing polymer chain segment and other low molecular weight substances, and semiconductor production apparatuses provided with the sealing material.
DISCLOSURE OF INVENTION
The present invention relates to the molding material comprising a fluorine-containing multi-segment polymer having an elastomeric fluorine-containing polymer chain segment (hereinafter referred to as “elastomeric segment A”) and a non-elastomeric fluorine-containing polymer chain segment (hereinafter referred to as “non-elastomeric segment B”), in which the elastomeric segment A imparts flexibility to the whole polymer and has perhaloolefin units as a recurring unit.
The molding material of the present invention contains perhaloolefin units as a recurring unit of the elastomeric segment A in an amount of not less than 90% by mole, preferably not less than 95% by mole.
In the present invention, the elastomeric segment A and/or the non-elastomeric segment B may contain recurring units derived from monomer giving a curing site to the respective segments in an amount of not more than 5% by mole based on each segment.
Also it is preferable that the elastomeric segment A is a non-crystalline segment and its glass transition temperature is not more than 25° C. and further that the segment A comprises tetrafluoroethylene (TFE)/perfluoro(alkyl vinyl ether) (PAVE)/monomer giving a curing site in an amount of 45 to 90/10 to 50/0 to 5% by mole.
It is preferable that the non-elastomeric segment B is a polymer chain having a crystalline melting point of not less than 150° C. and has perhaloolefin units as a recurring unit. Further it is preferable that the non-elastomeric segment B is a non-elastomeric segment comprising 85 to 100% by mole of TFE and 0 to 15% by mole of CF
2
═CF—R
f
1
, in which R
f
1
is CF
3
or OR
f
2
(R
f
2
is a perfluoroalkyl group having 1 to 5 carbon atoms).
The non-elastomeric segment B has at least one fluoroolefin unit and can be used preferably even if it has a haloolefin unit having hydrogen atom as a recurring unit as case demands.
In the molding material of the present invention, it is preferable that the fluorine-containing multi-segment polymer (for example, B-A-B, A-B, etc.) does not contain a polymer molecule C consisting of the elastomeric segment A which is not bonded to the non-elastomeric segment B or even if such a polymer molecule C is contained, its amount is not more than 35% by weight, particularly not more than 10% by weight, in other words, A/(A+C)≧65% by weight, particularly A/(A+C)≧90% by weight.
The present invention also relates to the crosslinkable molding composition comprising 100 parts by weight (hereinafter referred to as “part”) of the above-mentioned fluorine-containing multi-segment polymer having a curing site, 0.05 to 10 parts of an organic peroxide and 10 to 010 parts of a crosslinking aid.
Also the present invention relates to the crosslinkable molding composition comprising 100 parts of the above-mentioned fluorine-containing multi-segment polymer having a nitrile group as a curing site and 0.1 to 10 parts of a crosslinking agent having a functional group capable of reacting with the nitrile group.
The molding material and crosslinkable molding composition of the present invention can be used for various molded articles, and since contamination is hardly caused, they are particularly suitable as a sealing material for various production apparatuses in the semiconductor-related field.
Also it is preferable that the above-mentioned fluorine-containing multi-segment polymer is used as a sealing material after subjected to crosslinking by high energy rays.
Down-sizing of such a sealing material has advanced more and more and cleanliness thereof is demanded. Concretely a sealing material is built in semi-conductor production apparatuses, for example, etching system, cleaning equipme
Araki Takayuki
Irie Sadashige
Kishine Mitsuru
Kitaichi Masanori
Noguchi Tsuyoshi
Daikin Industries Ltd.
Mullis Jeffrey
Sughrue & Mion, PLLC
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