Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
1999-11-23
2001-09-18
Dawson, Robert (Department: 1712)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C106S287150, C106S287160, C525S101000, C526S279000
Reexamination Certificate
active
06291021
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to coating materials and more specifically to highly weathering-resistant coating materials that have an excellent gloss retention and water-repellency retention.
BACKGROUND OF THE INVENTION
Exposure to water, ultraviolet radiation, ozone, and other noxious factors can cause the unprotected surfaces of, for example, automobiles, various other vehicles, aircraft, bridges, buildings, etc., to suffer from timewise changes in quality (deterioration). This has led to the introduction of a large number of coating materials for the purpose of surface protection. Among the spectrum of coating materials, those based on acrylic resins are reported to have excellent resistance to weathering. Even in the case of acrylic resin coating materials, however, long-term exposure to such challenges as wind and rain and ultraviolet radiation still leads to degeneration and a concomitant decline in gloss, water repellency, and the protective film properties that were the initial reason for applying the coating.
As examples within the realm of coating materials that employ an organosilane or organopolysiloxane starting material, Japanese Application Number Sho 57-36109 teaches a coating material comprising a copolymer of &ggr;-methacryloxypropyltrimethoxysilane and acrylic monomer, while Japanese Application Number Hei 9-279064 teaches a coating material based on a copolymer of acrylic monomer and linear alkylpolysiloxane bearing the methacryloxy group at a single terminal. These coating materials, however, have suffered from such problems as a low film strength and an unacceptable water repellency and particularly an unacceptable water-repellency retention.
The object of this invention is to solve the problems described above by providing a highly weathering-resistant coating material that in particular has an excellent gloss retention and water-repellency retention.
SUMMARY OF THE INVENTION
The coating material of the invention characteristically has as its base ingredient a vinyl-type polymer that contains a pendant carbosiloxane dendrimer structure.
DETAILED DESCRIPTION OF THE INVENTION
The vinyl-type polymer constituting the coating material of the invention contains a carbosiloxane dendrimer structure in a side-chain or pendant position on the polymer (this polymer is referred to below as pendant carbosiloxane dendrimer-functional vinyl-type polymer). This carbosiloxane dendrimer structure denotes a high-molecular-weight group with a predictable and highly branched structure that elaborates radially from a single core. An example of a carbosiloxane dendrimer having such a structure in a side-chain position is the highly branched siloxane-silalkylene copolymer taught in the specification of Japanese Application Number Hei 9-171154.
The carbosiloxane dendrimer structure in the vinyl-type polymer in the coating material of the invention preferably is a group with the following general formula.
The group Z is a divalent organic group, for example, an alkylene group, arylene group, aralkylene group, ester-containing divalent organic group, ether-containing divalent organic group, ketone-containing divalent organic group, or amide-containing divalent organic group. Among the organic groups, those with the following structures are preferred.
—C(═O)—O—R
9
—
—C(═O)—NH—R
9
—
R
9
in the preceding structures represents C
1
to C
10
alkylene, for example, methylene, ethylene, propylene, and butylene with methylene and propylene being preferred. R
10
represents C
1
to C
10
alkyl, for example, methyl, ethyl, propyl, and butyl with methyl being preferred. R
11
represents C
1
to C
10
alkylene, for example, methylene, ethylene, propylene, and butylene with ethylene being preferred. The subscript d is an integer from 0 to 4, and the subscript e is 0 or 1. R
1
is C
1
to C
10
alkyl or aryl. The alkyl encompassed by R
1
is exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl, and cyclohexyl. The aryl encompassed by R
1
is exemplified by phenyl and naphthyl. Methyl and phenyl are preferred for R
1
, and methyl is particularly preferred. X
1
is the silylalkyl group with the following formula at i=1.
R
1
is defined as above. R
2
represents C
2
to C
10
alkylene and is exemplified by straight-chain alkylene such as ethylene, propylene, butylene, and hexylene, and by branched alkylene such as methylmethylene, methylethylene, 1-methylpentylene, and 1,4-dimethylbutylene. Ethylene, methylethylene, hexylene, 1-methylpentylene, and 1,4-dimethylbutylene are preferred for R
2
. R
3
is C
1
to C
10
alkyl and can be exemplified by methyl, ethyl, propyl, butyl, and isopropyl. In the formula, i is an integer with a value from 1 to 10 that specifies the generation of said silylalkyl group, and a
i
is an integer from 0 to 3.
Preferred for use in the coating material of the invention is a carbosiloxane dendrimer-functional vinyl-type polymer afforded by the polymerization of
(A) 0 to 99.9 weight parts vinyl monomer and
(B) 100 to 0.1 weight parts carbosiloxane dendrimer that contains a radically polymerizable organic group and has the following general formula
Y is a radically polymerizable organic group. R
1
is C
1
to C
10
alkyl or aryl. The alkyl encompassed by R
1
is exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl, and cyclohexyl. The aryl encompassed by R
1
is exemplified by phenyl and naphthyl. Methyl and phenyl are preferred for R
1
, and methyl is particularly preferred. X
1
is the silylalkyl group with the following formula at i=1.
R
1
is defined as above; R
2
is C
2
to C
10
alkylene; R
3
is C
1
to C
10
alkyl, for example, methyl, ethyl, propyl, and butyl; X
i+1
is selected from the set consisting of the hydrogen atom, C
1
to C
10
alkyl, aryl, and the above-defined silylalkyl group; i is an integer with a value from 1 to 10 that specifies the generation of said silylalkyl group; and a
i
is an integer from 0 to 3.
Considering this vinyl-type polymer in greater detail, the vinyl monomer (A) should contain a radically polymerizable vinyl group, but the type and other properties of this monomer are not otherwise critical. This vinyl monomer (A) is exemplified by the monomers used as starting monomers for the organic resins generally known as vinyl resins. The vinyl monomer (A) is more specifically exemplified by lower alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate; higher alkyl (meth)acrylates such as n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; the vinyl esters of lower aliphatic acids, such as vinyl acetate and vinyl propionate; the vinyl esters of higher aliphatic acids, such as vinyl butyrate, vinyl caproate, vinyl 2-ethylhexanoate, vinyl laurate, and vinyl stearate; aromatic vinyl monomers such as styrene, vinyltoluene, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and vinylpyrrolidone; amide-functional vinyl monomers such as (meth)acrylamide, N-methylol(meth)acrylamide, isobutoxymethoxy(meth)acrylamide, and N,N-dimethyl(meth)acrylamide; hydroxyl-functional vinyl monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate; fluorinated vinyl monomers such as trifluoropropyl (meth)acrylate, perfluorobutylethyl (meth)acrylate, and perfluorooctylethyl (meth)acrylate; epoxy-functional vinyl monomers such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate; carboxyl-functional vinyl monomers such as (meth)acrylic acid, itaconic acid, crotonic acid, and fumaric acid; ether linkage-containing vinyl monomers such as tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol mono(meth)acrylate, hydroxybutyl
Aso Takayuki
Furukawa Haruhiko
Morita Yoshitsugu
Brown Catherine U.
Dawson Robert
Dow Corning Toray Silicone Co. Ltd.
McKellar Robert L.
Richard Charles R.
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