Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1992-01-10
1994-01-11
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
428500, 525207, 525223, 5253276, 525375, 525382, C08F 832
Patent
active
052782492
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a curable coating composition based on a hydroxy-functional component and an anhydride-functional component.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,452,948 describes a coating composition suitable for use as a glossy pigmented coating for a rigid substrate, particularly where hardening of the coating at ambient temperatures is required, for example as a vehicle refinishing paint. The coating composition comprises a hydroxy component having at least two free hydroxy groups per molecule and an anhydride component having at least two cyclic carboxylic acid anhydride groups per molecule, at least one of these components being a film-forming polymer. The composition also includes a catalytically effective amount of amine groups, preferably present on the hydroxy component, for accelerating the curing reaction between the hydroxl groups and the anhydride groups.
European Patent Application 259172 describes a coating composition comprising an anhydride polymer containing at least two cyclic carboxylic acid anhydride groups and a polymer containing at least two functional groups reactive with anhydride groups. These reactive groups are selected from hydroxyalkylamino, hydroxyalkoxyalkylamino, hydroxy-substituted acyloxyalkylamino, hydroxy-substituted polyacyloxyalkylamino, mercaptoalkylamino and oxazolidino groups. One of the polymers comprises a flexible polymer chain selected from polyether, polyester, silicone, diene polymer, hydrogenated diene polymer, polyurethane, polyisobutylene and polyacrylate chains. The functional groups characteristic of that polymer are each present as a terminal group at the end of a flexible polymer chain. The cured coatings have increased resistance to impact and abrasion.
U.S. Pat. No. 4,798,745 describes a coating composition comprising a hydroxy component having at least two free hydroxy groups per molecule and an anhydride component having at least two carboxylic anhydride groups per molecule used in amounts to provide a ratio of equivalents of hydroxy groups to equivalents of anhydride groups of 3:1 to 1:3. The anhydride component is a copolymer of at least 11% by weight of an ethylenically unsaturated anhydride with a vinyl comonomer such as styrene which is used in a molar proportion of at least 1:1 with respect to the unsaturated anhydride.
Liu et al in J. Polymer Science, Part A: Polymer Chemistry, 26, pages 3015 to 3029 (1988), describe the preparation of 1,1'-bis(2-hydroxyethyl)-2,2'-biimidazole and its use in synthesising a series of new polyurethanes based on aromatic diisocyanates. Derwent Patent Abstract 83-829562 (an abstract of Japanese Patent Application 58-179271) describes a coating composition comprising a reaction product of a bis(hydroxy-imidazoline) and an epoxy resin, the product being neutralised with a volatile acid.
SUMMARY OF THE INVENTION
A coating composition according to the invention comprises (A) a hydroxy-functional component having at least two hydroxy groups per molecule and (B) an anhydride-functional component having at least two carboxylic anhydride groups per molecule, at least one of the components (A) and (B) being a film-forming polymer, and is characterised in that the coating composition contains amidine groups for accelerating the curing reaction between the hydroxy groups of component (A) and the anhydride groups of component (B), the amidine groups being present as a substituent group in component (A) or (B) and/or being present in the form of a separate compound containing an amidine group.
By an amidine group we mean a group of the formula ##STR2##
DETAILED DISCLOSURE
The component or compound containing an amidine group can for example have the formula ##STR3## in which R.sup.1 represents hydrogen, an organic group attached through a carbon atom, an amine group which can be substituted, for example by an optionally substituted hydrocarbyl group having up to 6 carbon atoms, or a hydroxy group which can be etherified, for example with an optionally substituted hydrocarb
REFERENCES:
patent: 4452948 (1984-06-01), Marrion et al.
patent: 4798745 (1989-01-01), Martz et al.
patent: 4946744 (1990-08-01), Shalati et al.
Liu et al., Journal of Polymer Science: Part A: Polymer Chemistry, vol. 26, 3015-3029 (1988).
Derwent Patent Abstract 83-829562 (an abstract of Japanese Patent Application 58-179271).
Courtaulds Coatings (Holdings) Limited
Schofer Joseph L.
Zitomer Fred
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