Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-08-05
2001-06-19
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C528S049000, C528S075000, C428S423100
Reexamination Certificate
active
06248828
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a paint which is used for waterproofing of rooftop, floor and outer wall of buildings, building materials, sports facilities such as tennis courts and athletic sports stadium, automobiles, household appliances, woodworking products, plastics molded articles, etc. and which can form a paint film excellent in weather resistance, for example, gloss retention, discoloration resistance, and crack resistance in long term outdoor use.
Hitherto, there have been known two-pack curing type paint compositions which comprise a composition containing active hydrogen and a composition having a functional group which reacts with active hydrogen. These paint compositions are excellent in chemical properties such as chemical resistance and, besides, can form a paint film superior in adhesion and strength and have been used as top coats of rooftop of buildings for waterproofing, outer wall of buildings, building materials and sports facilities.
Especially, when an acrylic polyol is used as the composition containing active hydrogen and an isocyanate is used as the functional group which reacts with active hydrogen, a paint film excellent in gloss, chemical properties and mechanical strength can be produced and these paint compositions have been generally used as outdoor paints.
However, when the paint films comprising the above paint compositions are used for a long period of time, they suffer from the problems in weather resistance, such as decrease of gloss, discoloration and cracking due to exposure to ultraviolet rays. For the solution of these problems, an ultraviolet absorber or a light stabilizer is added to the paint compositions. However, when used for a long time, the bleeding phenomenon of the ultraviolet absorber or light stabilizer coming to the surface is caused, and the effects of the additives cannot be retained for a long period of time.
In order to solve the above problems, attempts have been made to fix an ultraviolet absorber or a light stabilizer in the paint compositions. Thus, there has been proposed a method of copolymerizing an ultraviolet absorber or a light stabilizer which comprises an acrylic polyol having a polymerizable skeleton, and paint compositions comprising a polyisocyanate compound and a resin composition obtained by copolymerization of an acrylic polyol with an unsaturated monomer having a hydroxyl group, an unsaturated monomer having a cycloalkyl group, or the like have been reported (JP-A 9 (1997)-3393).
However, according to the above method, if the polyisocyanate compound is inferior in weather resistance or content of the polyisocyanate in the paint composition is high, the whole paint film sometimes deteriorates in weather resistance. Furthermore, in the case of the acrylic polyol of the above composition, dispersibility of pigments is inferior, and when pigment is contained, chalking phenomenon of the paint film occurs after lapse of long term, and the weather resistance cannot be sufficiently retained for a long period of time.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a paint in which the ultraviolet absorber or light stabilizer added to the two-pack curing type paints does not bleed and which can provide a paint film excellent in long-term weather resistance such as gloss retention and discoloration resistance in long-term outdoor use by imparting weather resistance to both the isocyanate component and the component reacting with the isocyanate component, without damaging physical properties and chemical properties of the paint.
The inventors has continued a research on paint compositions in an attempt to retain long-term weather resistance of paints. As a result, they have succeeded in obtaining an isocyanate compound having ultraviolet absorbability by reacting a polyisocyanate compound with an ultraviolet absorber having active hydrogen, and by reacting the resulting compound with a polymeric compound having active hydrogen or a polymeric compound having active hydrogen and a functional group on pendant having ultraviolet absorbability, it has become possible to impart ultraviolet absorbability to at least one, preferably both of these reacting compounds. Thus, a paint excellent in weather resistance has been provided, and the present invention has been accomplished.
That is, the present invention relates to a paint (compound or composition) having ultraviolet absorbability and curing function and comprising as an essential component an isocyanate compound (A) which has a functional group having ultraviolet absorbability on a side chain through chemical bond and contains residual isocyanate groups and which is obtained by reacting a part of isocyanate groups of an isocyanate prepolymer and/or monomer having at least two free isocyanate groups with an ultraviolet absorber having active hydrogen and represented by the formula (1) and/or the formula (2), and, if necessary, additionally comprising an optional isocyanate prepolymer (B) other than (A), and to a paint superior in weather resistance obtained by reacting said compound or composition with a polymeric compound having active hydrogen.
(in the formula (1), R
1
and R
2
each represent a hydrogen atom, a hydrocarbon group of 1-10 carbon atoms, or an alkoxy group of 1-10 carbon atoms, and R
3
represents a hydrogen atom, a halogen group, an alkoxy group of 1-10 carbon atoms, a cyano group, or a nitro group; in the formula (2), R
4
represents a hydrogen atom, a halogen group, an alkoxy group of 1-10 carbon atoms, or a hydrocarbon group of 1-10 carbon atoms, and R
5
represents hydrogen atom, an alkoxy group of 1-10 carbon atoms, or a hydrocarbon group of 1-10 carbon atoms).
Amount of the isocyanate prepolymer (B) is 0-99% by weight based on the total amount of (A) and (B).
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be explained in detail. As the isocyanate prepolymers or monomers used in the present invention, mention may be made of, for example, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, m-xylylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, cyclohexylmethane diisocyanate, and naphthalene diisocyanate; their isocyanurate compounds, biuret compounds, trimethylolpropane adducts, adducts with compounds having active hydrogen, such as amines, carboxylic acids, and alcohols, and adducts with derivatives thereof. These may be used each alone or in combination of two or more.
The ultraviolet absorbers having active hydrogen are those which are represented by the following formulas (1) and/or (2):
(in the formula (1), R
1
and R
2
each represent a hydrogen atom, a hydrocarbon group of 1-10 carbon atoms, or an alkoxy group of 1-10 carbon atoms, and R
3
represents a hydrogen atom, a halogen group, an alkoxy group of 1-10 carbon atoms, a cyano group, or a nitro group; in the formula (2), R
4
represents a hydrogen atom, a halogen group, an alkoxy group of 1-10 carbon atoms, or a hydrocarbon group of 1-10 carbon atoms, and R
5
represents hydrogen atom, an alkoxy group of 1-10 carbon atoms, or a hydrocarbon group of 1-10 carbon atoms). Examples thereof include benzotriazole ultraviolet absorbers such as 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-5′-t-butylphenyl)benzotriazole, 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole, and 2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole, and benzophenone ultraviolet absorbers such as 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-ethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxy-2′-chloro-benzophenone, and 2-hydroxy-4-octoxy-3′-methyl-benzophenone. These may be used each alone or in combination of two or more.
Furthermore, the reaction of the isocyanate prepolymer or monomer with the ultraviolet absorber having active hydrogen can be carried out with addition of compounds having active hydrogen, such as amines, carboxylic acids, alcohols and derivatives thereof, each alone
Yamazaki Takayoshi
Yanauchi Kazuo
Gorr Rachel
Pillsbury & Winthrop LLP
Taisei Chemical Industries, Ltd.
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