Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2000-03-31
2002-02-12
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C523S451000, C523S453000, C523S461000, C525S523000, C525S524000, C525S533000, C528S089000, C528S090000, C528S093000
Reexamination Certificate
active
06346329
ABSTRACT:
The present invention relates to a novel curable resin composition which is excellent in low temperature curability, has good storage stability and improved leveling property, and which is useful particularly in the field of paint.
Up to the present, in a resin composition comprising an epoxy resin and curing agent such as polycarboxylic acid anhydride, a curing catalyst such as tertiary amine, quaternary ammonium salt, etc. is usually combined in order to accelerate its curing.
The curable resin composition combined with said curing catalyst, however, has a problem of poor storage stability and short pot life, because said curing catalyst has a strong accelerating effect on the reaction between epoxy resin and curing agent.
In order to improve the storage stability of such a curable resin composition, Japanese Laid-open Patent Publication No. 133340/1995 proposes to use a potential curing catalyst composed of an onium salt and an acidic phosphoric acid ester such as mono- or di-alkyl phosphate, as a curing catalyst. Whereas, there still remains the problem with a curable resin composition which contains such a potential curing catalyst that its low temperature curability is reduced more or less, while its storage stability is improved.
Surprisingly, however, it is now found that a curable resin composition excelling in both storage stability and low temperature curability and furthermore exhibiting improved leveling property can be obtained when a chemical reaction product of diphenyl phosphate, which is not taught in said Japanese Publication, with an onium salt is used as the potential curing catalyst.
Thus, according to the present invention there is provided a curable resin composition which comprises:
(A) a polyepoxide compound,
(B) a curing agent containing at least one functional group selected from carboxyl group and acid anhydride group, and
(C) a potential curing catalyst composed of a reaction product of an onium salt with diphenyl phosphate.
Hereafter the curable resin composition of the present invention is described in more detail.
(A) Polyepoxide Compound
The polyepoxide compound (A) used in the resin composition of the present invention is a resin having on average about 2 or more epoxy groups per molecule. As the polyepoxide compound (A) any compounds known per se in the field of curable resin composition, particularly in the field of paint, can be used. Generally, however, there can be particularly favorably used an acrylic resin containing on average 2-50, preferably 6-35, epoxy groups per molecule and having a weight-average molecular weight in the range of from about 1,500 to about 15,000, preferably about 2,000 to about 10,000, for forming a cured coating film with good performances such as finishing appearance, surface smoothness, outdoor weatherability, etc.
As said acrylic resin containing epoxy groups there is included, for example, an acrylic copolymer containing epoxy groups which is obtained by radical copolymerization of a monomer containing epoxy group, which has one each of epoxy group and ethylenic unsaturated group such as (meth)acryloyl group per molecule, for example glycidyl (meth)acrylate, allyl glycidyl ether, etc. with one or more of other radical-polymerizable unsaturated monomers.
The copolymer thus obtained can contain generally about 5 to about 60% by weight, preferably about 15 to about 55% by weight, inter alia, about 20 to about 50% by weight, of the structural unit derived from the above-mentioned monomer containing epoxy group, based upon the weight of said copolymer.
As such other polymerizable unsaturated monomers copolymerizable with the above-mentioned monomer containing epoxy group, there are included, for example, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylates, etc.; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, etc.; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylates, etc. and such ethylenic unsaturated monomers containing hydroxyl group as adducts of monomers with &egr;-caprolactone; fluoro-alkyl (meth)acrylates such as perfluorooctyl (meth)acrylate, etc.; vinyl aromatic compounds such as styrene, vinyltoluene, etc.; unsaturated nitrile compounds such as (meth)acrylonitrile, etc.; fluoro-olefins such as tetrafluoroethylene, trifluorochloroethylene, vinylidene fluoride, vinyl fluoride, etc.; vinyl esters, olefin compounds, etc. They can be used each singly or in combination of two or more.
Copolymerization method of the above-mentioned monomer containing epoxy group and other polymerizable unsaturated monomer or monomers is not critical, but can be conducted by any method known per se, for example, solution polymerization, suspension polymerization, emulsion polymerization, etc.
(B) Curing Agent
The curing agent (B) used in the resin composition of the present invention includes polyfunctional substances which contain functional groups selected from carboxyl group and acid anhydride group
As said curing agent there are included polycarboxylic acid curing agent containing at least two carboxyl groups per molecule; acid anhydride curing agent containing at least one acid anhydride group per molecule; acid anhydride curing agent containing carboxyl group, which contains at least one carboxyl group and at least one acid anhydride group per molecule, etc.
As polycarboxylic acid curing agent there are included, for example, as low molecular weight polycarboxylic acid, for example, tetrahydrophthalic acid, hexahydrophthalic acid, phthalic acid, trimellitic acid, 1,5-naphthalenedicarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, etc.; as high molecular weight polycarboxylic acid, for example, polycarboxylic acid resin of vinyl-type, polyester type, etc. (usually having weight average molecular weight in the range of about 500 to about 80,000, particularly 2,000 to 20,000 and acid value in the range of 20 to 350 mgKOH/g, particularly 80 to 200 mgKOH/g).
As the above-mentioned vinyl type polycarboxylic acid resin there can be mentioned, for example, (co)polymers obtained by radical polymerization of carboxyl group-containing ethylenic unsaturated monomers, for example, (meth)acrylic acid, crotonic acid, half-esterified product of 3,6-endomethylene tetrahydrophthalic anhydride and such ethylenic unsaturated monomers containing hydroxyl group as those mentioned above or the like, if necessary with such other ethylenic unsaturated monomers as mentioned above; half esterified products of (co)polymers which are obtained by radical polymerization of ethylenic unsaturated monomers containing acid anhydride groups, for example, itaconic anhydride, maleic anhydride, etc. if necessary with such other ethylenic unsaturated monomers as those mentioned above, and further half-esterifying the same using an esterifying agent, for example, methanol ethanol propanol, butanol, pentanol hexanol, octanol acetol allyl alcohol, propargyl alcohol etc.; (co)polymers obtained by radical polymerization of monomers which are obtained by half esterification of such ethylenic unsaturated monomers containing acid anhydride groups as mentioned above with such an esterifying agent as mentioned above, if necessary together with such other ethylenic unsaturated monomers as those mentioned above; half esterified products of (co)polymers containing hydroxyl groups which are obtained by radical polymerization of such ethylenic unsaturated monomers containing hydroxyl groups as those mentioned above if necessary with such other ethylenic unsaturated monomers as those mentioned above, and half-esterifying the same using carboxylic anhydride, for example, acetic anhydride, succinic anhydride, etc.
The above-mentioned polyester type polycarboxylic acid resin is an esterified product of a polybasic acid component and polyhydric alcohol component under the condition of excess amount of polybasic acid component. As the polybasic acid component there can be ment
Aylward D.
Kansai Paint Co. Ltd.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Curable resin composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Curable resin composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Curable resin composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2970000