Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1996-12-11
1998-05-12
Marquis, Melvyn I.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
524300, 524399, 524773, 524783, 427387, 428447, C08F 800
Patent
active
057506248
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a curable resin composition capable of forming a coating film of excellent quality in terms of acid resistance, mar resistance and appearance and, therefore, finding application in the fields of automotive top coatings, coil coatings, household electrical appliances, plastics and electrical materials, among other uses, and to a coating composition, a method of forming a coating film, and a coated article each as obtainable or implementable using said curable resin composition.
PRIOR ART
Automotive top coatings and a variety of coatings dedicated to the same purpose are required to possess a function to provide an aesthetic appearance and prolong the life of the car by evading damages due to winds and rains, stones, muds and dust by constituting the outermost layer of the coating structure inclusive of the primer and intermediate coating layers on the body of a car or the like and, therefore, must provide a film with high mar resistance and good appearance. The resin compositions used in such coatings are so designed that they will show viscosities before coating within a certain range that facilitates coating and, after application, may be easily cured to provide necessary resistance and appearance, that is to say they may exhibit a long storage stability and the optimum curability.
The conventional curing system for such automotive top coatings is an aminoplast curing agent such as a melamine resin which reacts with the hydroxyl groups of a hydroxyl group-containing polymer to achieve curing. However, the above curing system is unsatisfactory in acid resistance and the coating film obtained is liable to develop defects owing to acidic rains which have recently been a major problem. The defects are generally attributed to the triazine nucleus of the melamine resin and no improvement in acid resistance could be realized unless the use of melamine resin was avoided or restricted to a sufficiently low level to avoid said defects.
As a curing system not using a melamine resin, a method employing a polyisocyanate compound is known but the toxicity problem associated with the isocyanate has not been resolved. Therefore, a curable resin composition of high nonvolatile content comprising a polyoxide of low molecular weight, a hydroxyl group-containing polyfunctional substance of low molecular weight, a curing agent essentially comprising an anhydride, and an acid catalyst was proposed (Japanese Kokai Publication Sho-63-84674). However, this composition was found to have the disadvantage that because its ingredients are so reactive to each other that it cannot be stored in one package, presenting a storage stability problem.
In view of the above state of the art, a technology employing both (1) a half-esterified copolymer and (2) an epoxy group- and hydroxyl group-containing compound in a defined ratio to overcome the above-mentioned disadvantage was disclosed (Japanese Patent Application Hei-2-91299). This composition provided high acid resistance to overcome the above disadvantage but was inadequate in mar resistance.
In view of the above problem, a technology was proposed in which, in addition to the use of both (1) a half-esterified (inclusive of half-thioesterified and half-amidated) copolymer and (2) an epoxy group- and hydroxyl group-containing compound, (3) at least one member selected from among an acrylic polymer, a fluorine-containing copolymer and a polyester resin, and (4) a melamine resin are used to provide a composition according to a well-considered formula to thereby overcome the above-mentioned disadvantage (Japanese Kokai Publication Hei-4-363374). Although it contains a melamine resin, this composition satisfies the acid resistance requirement to a certain extent and provides good mar resistance.
In the above technologies, the curing systems used essentially require sufficiently high functional group concentrations, so that the inevitable high viscosities called for fair amounts of solvents. As such, these technologies are unsuitable f
REFERENCES:
patent: 5026793 (1991-06-01), Nakai et al.
patent: 5344879 (1994-09-01), Inoue et al.
patent: 5374682 (1994-12-01), Gouda et al.
patent: 5416165 (1995-05-01), Okimura et al.
patent: 5432233 (1995-07-01), Miyazoe et al.
patent: 5464901 (1995-11-01), Yoshikawa
Fushimi Akira
Inoue Masanobu
Miyazoe Seigo
Marquis Melvyn I.
Nippon Paint Co. Ltd.
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