Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-10-03
2003-04-01
Reddick, Judy M. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C523S402000, C523S406000, C523S414000, C523S421000, C524S114000, C524S188000, C524S262000, C524S535000, C524S547000
Reexamination Certificate
active
06541562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aqueous paint composition which comprises an aqueous dispersion of a certain organic/inorganic composite resin and its curing agent and which is capable of forming a coating film excellent in hot water resistance, weather resistance, stain resistance, solvent resistance, alkali resistance, etc.
2. Discussion of the Background
A coating film formed by using, as a binder, an organic/inorganic composite resin obtained by subjecting an organosilane and/or its partially hydrolyzed condensate and a silyl group-containing vinyl resin to a hydrolytic condensation reaction, is excellent in weather resistance, stain resistance, etc. and is scarcely susceptible to cracking, like a coating film formed by using an organopolysiloxane type inorganic resin as a binder. Accordingly, an attention has been drawn to a coating composition containing such an organic/inorganic composite resin as a binder.
However, many of such coating compositions are organic solvent type paints, which are not preferable from the viewpoint of air pollution or conservation of resources, and further, there has been a problem that the obtained coating films are poor in e.g. hot water resistance or alkali resistance.
Further, aqueous paints employing organic/inorganic composite resins as binders, are disclosed in JP-B-7-116361, JP-A-11-293131 and JP-A-2000-44807.
JP-B-7-116361 discloses a method wherein a radical polymerizable silane coupling agent and a silane monomer are subjected to a hydrolytic copolymerization reaction, then to radical copolymerization with e.g. a hydrophilic group-containing vinyl monomer, and the obtained resin is neutralized and phase-transferred to water. However, gelation is likely to take place at the time of the radical copolymerization reaction, and there has been a problem that the obtained coating film is poor in e.g. weather resistance or hot water resistance.
JP-A-11-293131 discloses a method wherein a radical polymerizable silane coupling agent, a hydrophilic group-containing vinyl monomer, a radical polymerizable dimethyl polysiloxane, etc., are subjected to radical copolymerization, and the obtained resin is phase-transferred to water. However, there has been a problem that the coating film thereby obtainable is poor in stain resistance or weather resistance.
JP-A-2000-44807 discloses a polysiloxane-containing water-soluble resin obtained by reacting a water-soluble resin having siloxane bonds with a tetra functional alkoxysilane, but there has been a problem that the coating film thereby obtainable is susceptible to cracking and poor in hot water resistance or weather resistance.
SUMMARY OF THE INVENTION
The present invention has been made in view of such problems of the prior art, and it is an object of the present invention to provide an aqueous paint composition capable of forming a coating film excellent in hot water resistance, alkali resistance, weather resistance, stain resistance, etc., by employing an aqueous dispersion of a certain organic/inorganic composite resin and compounds having a specific functional group.
Namely, the present invention provides an aqueous paint composition comprising:
(i) an aqueous dispersion obtained by neutralizing with a neutralizing agent a hydrolytic condensation reaction product of (a) 100 parts by weight of an organosilane of the formula (1) R
1
n
Si(OR
2
)
4-n
, wherein R
1
is a C
1-8
organic group, R
2
is a C
1-5
alkyl group, and n is 1 or 2, and/or its partially hydrolyzed condensate, with (b) from 5 to 200 parts by weight of a silyl group-containing vinyl resin having hydrolyzable silyl groups or silyl groups having silicon atoms bonded to hydroxyl groups and having an acid value of from 20 to 150 mgKOH/g, and adding water thereto,
(ii) an amino group-containing alkoxysilane compound, and
(iii) an epoxy group-containing compound.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the present invention will be described in detail with reference to the preferred embodiments.
The respective constituting components of the aqueous paint composition of the present invention will be described.
With Respect to Component (i)
Firstly, the respective components used for the preparation of component (i) which is an aqueous dispersion of an organic/inorganic composite resin, will be described.
Component (a)
Component (a) is an organosilane of the formula (1) R
1
n
Si (OR
2
)
4-n
, wherein R
1
is a C
1-8
organic group, R
2
is a C
1-5
alkyl group, and n is 1 or 2, and/or its partially hydrolyzed condensate.
The organic group as R
1
in the above formula may, for example, be an alkyl group, a cycloalkyl group, an aryl group or a vinyl group.
Here, the alkyl group may be linear or branched. The alkyl group may, for example, be a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group, a s-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group or an octyl group. A preferred alkyl group is one having from 1 to 4 carbon atoms.
The cycloalkyl group may, for example, be preferably a cyclohexyl group, a cycloheptyl group or a cyclooctyl group.
The aryl group may, for example, be a phenyl group.
The above respective functional groups may have optional substituents. Such substituents may, for example, be a halogen atom (such as a chlorine atom, a bromine atom or a fluorine atom), a (meth)acryloyl group, a mercapto group, and an alicyclic group.
The alkyl group as R
2
may be linear or branched.
The alkyl group may, for example, be a methyl group, an ethyl group, n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group, a s-butyl group, a t-butyl group or a pentyl group. A preferred alkyl group is one having one or two carbon atoms.
Specific examples of the above formula (1) include, for example, methyltrimethoxysilane,
methyltriethoxysilane, ethyltrimethoxysilane,
ethyltriethoxysilane, n-propyltrimethoxysilane,
n-propyltriethoxysilane, i-propyltrimethoxysilane,
i-propyltriethoxysilane, &ggr;-chloropropyltrimethoxysilane,
&ggr;-chloropropyltriethoxysilane, vinyltrimethoxysilane,
vinyltriethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane,
3,3,3-trifluoropropyltriethoxysilane,
cyclohexyltrimethoxysilane,
&ggr;-methacryloxypropyltrimethoxysilane,
&ggr;-methacryloxypropyltriethoxysilane,
&ggr;-mercaptopropyltrimethoxysilane,
&ggr;-mercaptopropyltriethoxysilane, phenyltrimethoxysilane,
phenyltriethoxysilane, dimethyldimethoxysilane,
dimethyldiethoxysilane, diethyldimethoxysilane,
diethyldiethoxysilane, diphenyldimethoxysilane,
diphenyldiethoxysilane, methylphenyldimethoxysilane and
dimethyldipropoxysilane. Preferred is
methyltrimethoxysilane, methyltriethoxysilane or
dimethyldimethoxysilane.
These organosilanes may be used alone or in combination as a mixture of two or more of them.
Component (a) may be a partially hydrolyzed condensate of the above described organosilane. The weight average molecular weight of such a condensate calculated as polystyrene is, for example, from 300 to 5,000, preferably from 500 to 3,000. By using a condensate having such a molecular weight, it is possible to obtain a coating film having a good adhesive property without deteriorating the storage stability. Further, the partially hydrolyzed condensate of the organosilane has at least one, preferably from 3 to 30, —OH groups or —OR
2
groups bonded to silicon atoms.
Specific examples of such a condensate include, as commercial products, SH6018, SR2402, DC3037 and DC3074, manufactured by Torey Dow Corning K.K.; KR-211, KR-212, KR-213, KR-214, KR-216 and KR-218, manufactured by Shin-Etsu Chemical Co., Ltd.; and TSR-145, TSR-160, TSR-165 and YR-3187, manufactured by Toshiba-Silicon K.K.
In the present invention, component (a) is preferably a mixture of (a-1) the organosilane of the above formula wherein n is 1 and/or its partially hydrolyzed condensate, and (a-2) the organosilane of the above formula wherein n is 2 and/or its partially hydrolyzed condensate in a weight ratio of from 50:50 to 100:0, preferably from 60:40 t
Aoki Ryuichi
Hatakeyama Tadashi
Sasaki Hiroharu
Tsuneta Kazuyoshi
Dai Nippon Toryo Co., Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Reddick Judy M.
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