Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2001-07-31
2003-10-21
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C525S101000, C525S185000, C525S187000, C525S191000, C525S222000, C528S026000, C528S027000, C528S028000, C427S299000
Reexamination Certificate
active
06635351
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a clear coating composition, a method of forming a coating film, and a multilayer coating film.
BACKGROUND ART
Among problems encountered by car drivers of late, the problem of bird droppings sticking to the coating film of the parked car, which droppings can be removed only with difficulty, and the problem of splashes of mud staining the car coating film as found after driving through wet weather, which necessitates washing of the car with rubbing, are of great concern. With the recent years' growth in demand for high-quality, maintenance-free cars, coating systems resistant to staining and capable of being deprived of stains in the event of staining have been demanded.
In car production lines, on the other hand, it is difficult to entirely prevent the occurrence of troubles due to adhesion of motes, dirt or the like. The coating film to which such a dirtying substance has adhered is repaired by recoating. In such cases, it has been common practice to remove the dirtying substance, polish the dirtied site, and recoat the polished site. From the work simplification and other points of view, coating systems capable of providing for a recoating film with good adhesion without polishing of the dirtied surface (hereinafter referred to as non-sanding recoatability) have been searched for.
Japanese Kokai Publication Hei-7-292313 describes an automotive coating composition capable of providing coating films well balanced among adhesion to the undercoat, scratch resistance, water resistance, oil resistance, weathering resistance, stain resistance and gloss which comprises a copolymer resulting from copolymerization of a silicone oligomer having ladder structure (hereinafter referred to as ladder silicone oligomer) having a specified molecular weight and a (meth)acryloxyalkyl group content in side chains of each molecule of 1 to 50% with at least one monomer selected from among (meth)acrylate esters, (meth)acrylamide, methylol(meth)acrylamide, alkoxymethylol(meth)acrylamides, unsaturated carboxylic acids, styrene and vinyl esters, as well as an organic solvent therefor, an ultraviolet absorber, an antioxidant and a crosslinking agent incorporated therein. In the automotive coating composition described in the above-cited publication Japanese Kokai Publication Hei-07-292313, the copolymer included ladder silicone oligomer (hereinafter referred to as ladder silicone copolymer), together with the crosslinking agent, constitutes the main component of the vehicle. From the non-sanding recoatability viewpoint, however, the composition is still unsatisfactory.
SUMMARY OF THE INVENTION
It is a primary object of the invention to provide a clear coating composition, which can give coating films showing good water repellency, in other words a factor giving a care-free and deluxe feeling to car owners, and which are excellent in non-sanding recoatability in recoating dirtied coatings after due repair, as well as a method of forming a coating film and a multilayered coating film.
The present inventors made intensive investigations in an attempt to accomplish the above object and have now completed the present invention.
Thus, in a first aspect, the invention provides a clear coating composition which comprises:
(A) 100 parts by mass of a mixture of a crosslinkable coating film-forming resin and a crosslinking agent on the solid basis
and (B) 0.01 to 2 parts by mass of a ladder silicone copolymer obtainable by copolymerizing (b-1) a (meth)acryloxyalkyl-containing ladder silicone oligomer, (b-2) a crosslinkable functional group-containing ethylenically unsaturated monomer and optionally (b-3) another copolymerizable ethylenically unsaturated monomer.
In a second aspect, the invention provides a clear coating composition which comprises:
(C) 20 to 60% by mass of a carboxyl- and carboxylate ester group-containing polymer obtainable by reacting an acid anhydride group-containing polymer obtainable from 15 to 40% by mass of (c-1) an acid anhydride group-containing ethylenically unsaturated monomer and 60 to 85% by mass of (c-2) another copolymerizable ethylenically unsaturated monomer with (c-3) a monohydric alcohol containing 1 to 12 carbon atoms in proportions such that the mole ratio between acid anhydride and hydroxyl groups amounts to 1/10 to 1/1,
(D) 0.1 to 60% by mass of a hydroxyl- and glycidyl containing polymer obtainable by copolymerizing 5 to 60% by mass of (d-1) a hydroxyl-containing ethylenically unsaturated monomer having the structure represented by the formula (1):
wherein R is a hydrogen atom or a methyl group, X is a straight or branched alkylene or hydroxyalkylene group, m is an integer of 2 to 8, n is an integer of 3 to 7 and q is an integer of 0 to 4, 10 to 60% by mass of a glycidyl-containing ethylenically unsaturated monomer (d-2) and optionally 0 to 85% by mass of (d-3) another copolymerizable ethylenically unsaturated monomer,
and (E) 0.01 to 60% by mass of a hydroxyl-, glycidyl- and ladder silicone-containing polymer obtainable by copolymerizing 5 to 60% by mass of (e-1) a hydroxyl-containing ethylenically unsaturated monomer represented by the formula (2):
wherein R′ is a hydrogen atom or a methyl group, X′ is a straight or branched alkylene or hydroxyalkylene group, m′ is an integer of 2 to 8, n′ is an integer of 3 to 7 and q′ is an integer of 0 to 4, 10 to 60% by mass of (e-2) a glycidyl-containing ethylenically unsaturated monomer, 1 to 30% by mass of (e-3) a (meth)acryloxyalkyl-containing ladder silicone oligomer and optionally 0 to 85% by mass of (e-4) another copolymerizable ethylenically unsaturated monomer.
In a third aspect, the invention provides a clear coating composition which comprises:
(C) 20 to 60% by mass of a carboxyl- and carboxylate ester group-containing polymer obtainable by reacting an acid anhydride group-containing polymer obtainable from 15 to 40% by mass of (c-1) an acid anhydride group-containing ethylenically unsaturated monomer and 60 to 85% by mass of (c-2) another copolymerizable ethylenically unsaturated monomer with (c-3) a monohydric alcohol containing 1 to 12 carbon atoms in proportions such that the mole ratio between acid anhydride and hydroxyl groups amounts to 1/10 to 1/1,
(D) 10 to 60% by mass of a hydroxyl- and glycidyl-containing polymer obtainable by copolymerizing 5 to 60% by mass of (d-1) a hydroxyl-containing ethylenically unsaturated monomer having the structure represented by the formula (1):
wherein R is a hydrogen atom or a methyl group, X is a straight or branched alkylene or hydroxyalkylene group, m is an integer of 2 to 8, n is an integer of 3 to 7 and q is an integer of 0 to 4, 10 to 60% by mass of (d-2) a glycidyl-containing ethylenically unsaturated monomer and optionally 0 to 85% by mass of (d-3) another copolymerizable ethylenically unsaturated monomer,
(E) 0.1 to 25% by mass of a hydroxyl-, glycidyl- and ladder silicone-containing polymer obtainable by copolymerizing 5 to 60% by mass of (e-1) a hydroxyl-containing ethylenically unsaturated monomer represented by the formula (2):
wherein R′ is a hydrogen atom or a methyl group, X′ is a straight or branched alkylene or hydroxyalkylene group, m′ is an integer of 2 to 8, n′ is an integer of 3 to 7 and q′ is an integer of 0 to 4, 10 to 60% by mass of (e-2) a glycidyl-containing ethylenically unsaturated monomer, 1 to 30% by mass of (e-3) a (meth)acryloxyalkyl-containing ladder silicone oligomer and optionally 0 to 85% by mass of (e-4) another copolymerizable ethylenically unsaturated monomer,
and (F) a polyethylene oxide- or polypropylene oxide-modified polysilicone compound.
It also provides a method of forming a coating film which comprises:
forming a metallic or solid base coating film on a substrate directly or via an undercoating film,
and then, without curing said metallic or solid base coating film, forming a clear coating film thereon by applying the above clear coating composition
and subjecting said metallic or solid base coating film and the cle
Ishihara Tatsuya
Mizuno Tetsuji
Moriwake Takashi
Nagao Goro
Tanabe Hisaki
Dawson Robert
Jordan and Hamburg LLP
Keehan Christopher
Nissan Motor Co,. Ltd.
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