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
2001-10-29
2003-05-20
Niland, Patrick D. (Department: 1714)
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...
C524S507000, C524S590000, C525S123000, C525S127000, C525S128000, C525S455000
Reexamination Certificate
active
06566445
ABSTRACT:
This application is the national phase of International Patent Application No. PCT/EP00/01953, filed on Mar. 6, 2000, and which claims priority of European Patent Application No. 99200741.9, filed Mar. 12, 1999.
BACKGROUND OF THE INVENTION
The present invention relates to a filler composition comprising a hydroxy group-containing polyacrylate, a polyisocyanate, and a pigment.
Filler compositions are known from DE-A-35 46 594 and GB 2 186 281. Both publications disclose filler compositions which comprise hydroxy group-containing polyacrylates and polyisocyanates. These filler compositions are too soft when cured, resulting in a moderate sandability.
SUMMARY OF THE INVENTION
The present invention now provides a filler composition comprising
A) at least one hydroxy group-containing polyacrylate comprising
40-70 wt. % aromatic vinyl monomers and/or methyl methacrylate,
25-40 wt. % hydroxy-functional (meth)acrylic monomers,
0-20 wt. % (meth)acrylic monomers having at least 2 carbon atoms in the alkyl group, and
0.5-2.5 wt. % (meth)acrylic acid,
wherein the hydroxy group-containing polyacrylate has a hydroxy value of between 100 and 160 mg KOH/g solid resin, an acid value between 5 and 20 mg KOH/g solid resin, a Mw higher than 15,000, and a Tg between 25 and 100° C.,
B) at least one polyisocyanate compound, and
C) at least one pigment,
the filler composition having a pigment volume concentration ranging from 40 to 80% on solids.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a filler composition with excellent balance between pot life and drying/sandability properties, build versus drying time, and viscosity and flow. The filler may be used for sanding and non-sanding applications, cured with a large variety of polyisocyanates, and covered with conventional top coats. The filler may be used within a broad temperature and humidity range. Properties such as sandability, adhesion to substrate and top coat, pot life, corrosion resistance, water resistance, enamel hold out, hardness, and in-can stability are equal to those of commercial fillers or improvements thereon.
The hydroxy group-containing polyacrylate may be prepared from aromatic vinyl compounds, methyl methacrylate, hydroxy-functional (meth)acrylic monomers, (meth)acrylic monomers having at least 2 carbon atoms in the alkyl group, and (meth)acrylic acid. Examples of aromatic vinyl compounds include styrene and its derivatives, such as vinyl toluene and mixtures thereof. Hydroxy-functional (meth)acrylic monomers preferably have 2 to 4 carbon atoms in the alkyl component. Examples of hydroxy-functional (meth)acrylic monomers include hydroxy ethyl (meth)acrylate, hydroxy propyl (meth)acrylate, hydroxy butyl (meth)acrylate, and mixtures thereof. (Meth)acrylic monomers preferably have 2 to 6 carbon atoms in the alkyl component. Examples of (meth)acrylic monomers include ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate and mixtures thereof. The terms (meth)acrylate and (meth)acrylic acid refer to methacrylate and acrylate as well as methacrylic acid and acrylic acid, respectively. The hydroxy group-containing polyacrylate is prepared by conventional methods, for instance, by the slow addition of appropriate monomers to a solution of an appropriate polymerisation initiator, such as an azo or peroxy initiator.
Preferably, the hydroxy group-containing polyacrylate comprises:
47-53 wt. % aromatic vinyl monomers, such as styrene, and/or methyl methacrylate,
28-33 wt. % hydroxy-functional (meth)acrylic monomers, such as hydroxy ethyl (meth)acrylate,
14-19 wt. % (meth)acrylic monomers having at least 2 carbon atoms in the alkyl group, such as butyl acrylate, and
0.5-2 wt. % (meth)acrylic acid.
The hydroxy group-containing polyacrylate has a hydroxy value of between 100 and 160 mg KOH/g solid resin, preferably between 110 and 130 mg KOH/g solid resin. The acid value of the hydroxy group-containing polyacrylate is between 5 and 20 mg KOH/g solid resin. The weight average molecular weight (Mw) of the polymer is higher than 15,000, as measured by gel permeation chromatography with polystyrene as standard, preferably between 15,000 and 30,000. The glass transition temperature (Tg) is between 25 and 100° C., preferably 40 to 60° C., calculated from the glass transition temperatures of the homopolymer of the individual monomers quoted in the literature (Fox equation, see, e.g., Batzer,
Polymeric Material,
1935, p. 307).
The polyisocyanate compound is a cross-linker which reacts with hydroxy groups. Polyisocyanates are compounds with two or more isocyanate groups per molecule, and are well-known in the filler art. Suitable polyisocyanates are aliphatic polyisocyanates such as trimethylene diisocyanate, 1,2-propylene diisocyanate, tetramethylene diisocyanate, 2,3-butylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 4-isocyanatomethyl-1,8-octane diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, dodecamethylene diisocyanate, &agr;,&agr;′-dipropyl ether diisocyanate, and transvinylidene diisocyanate; alicyclic polyisocyanates, such as 1,3-cyclopentylene diisocyanate, 1,2-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4-methyl-1,3-cyclohexylene diisocyanate, 4,4′-dicyclohexylene diisocyanate methane, 3,3′-dimethyl-4,4′-dicyclohexylene diisocyanate methane, norbornane diisocyanate, and isophorone diisocyanate; aromatic polyisocyanates such as m- and p-phenylene diisocyanate, 1,3- and 1,4-bis(isocyanate methyl) benzene, 1,5-dimethyl-2,4-bis(isocyanate methyl) benzene, 1,3,5-triisocyanate benzene, 2,4- and 2,6-toluene diisocyanate, 2,4,6-toluene triisocyanate, (&agr;,&agr;,&agr;′,&agr;′-tetramethyl o-, m-, and p-xylylene diisocyanate, 4,4′-diphenylene diisocyanate methane, 4,4′-diphenylene diisocyanate, 3,3′-dichloro-4,4′-diphenylene diisocyanate, and naphthalene-1,5-diisocyanate; and mixtures of the aforementioned polyisocyanates.
Also, such compounds may be adducts of polyisocyanates, e.g., biurets, isocyanurates, allophanates, uretdiones, prepolymers of polyisocyanates, and mixtures thereof. Examples of such adducts are the adduct of two molecules of hexamethylene diisocyanate or isophorone diisocyanate to a diol such as ethylene glycol, the adduct of 3 molecules of hexamethylene diisocyanate to 1 molecule of water, the adduct of 1 molecule of trimethylol propane to 3 molecules of isophorone diisocyanate, the reaction product of 3 moles of m-&agr;,&agr;,&agr;′,&agr;′-tetramethylxylene diisocyanate with 1 mole of trimethylol propane, the adduct of 1 molecule of pentaerythritol to 4 molecules of toluene diisocyanate, the isocyanurate of hexamethylene diisocyanate, available from Bayer under the trade designation Desmodur® N3390 and Desmodur® N3600, the uretdione of hexamethylene diisocyanate, available from Bayer under the trade designation Desmodur® N3400, the allophanate of hexamethylene diisocyanate, available from Bayer under the trade designation Desmodur® LS 2101, the adduct of 3 moles of toluene diisocyanate to 1 mole of trimethylol propane, available from Bayer under the trade designation Desmodur® L, and the isocyanurate of isophorone diisocyanate, available from Huils under the trade designation Vestanat® T1890. Furthermore, (co)polymers of isocyanate-functional monomers such as &agr;,&agr;′-dimethyl-m-isopropenyl benzyl isocyanate are suitable for use. Finally, the above-mentioned isocyanates and adducts thereof may be present in the form of blocked isocyanates, as is known to the skilled man.
Preferred are the isocyanurate of hexamethylene diisocyanate, the biuret of hexamethylene diisocyanate, the isocyanurate of isophorone diisocyanate, mixtures of biuret of hexamethylene diisocyanate and isocyanurate of isophorone diisocyanate, and mixtures of isocyanurate of hexamethylene diisocyanate and isocyanurate of isophorone diisocyanate.
The polyisocyanate compound is used in an amount such that the ratio of isocyanate groups to the total n
De Jong Cornelis
Krabbe Marieke
Van Kesteren Peter
Akzo Nobel N.V.
McGillycuddy Joan M.
Niland Patrick D.
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