Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-04-03
2001-12-18
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C525S165000, C525S222000, C525S231000, C525S529000
Reexamination Certificate
active
06331582
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to liquid surface coatings and more particularly to a matting agent in such coatings to reduce gloss.
Appearance coatings having good mechanical properties such as hardness, flexibility, durability, etc. with low gloss are used in vehicle interiors, furniture surfaces and the like. Low gloss is often provided by a significant amount of pigment in the coating formulation to roughen and therefore reduce surface gloss.
Silicon-containing compounds and polymers (e.g. silica, silicate and silane) and fillers such as diatomaceous earth, clays, zeolites and the like are also known to reduce gloss in surface coatings. Compositions with these components often contain significant amounts of organic solvent which render them sometimes hazardous to handle.
SUMMARY OF THE INVENTION
A primary object of this invention is to provide liquid coating compositions containing a matting agent to reduce coating gloss without adversely affecting other desirable performance properties of the coating.
These and other objects are accomplished by a liquid surface coating composition which, after curing or drying, possesses low gloss, the composition comprising in admixture:
a) a binder resin other than polyvinyl acetal resin;
b) pigment colorant; and
c) a gloss-reducing amount of a matting agent consisting essentially of polyvinyl acetal containing acetal groups derived from one or more aliphatic or aromatic aldehydes having 1 to 10 carbon atoms.
The polyvinyl acetal is preferably polyvinyl butyral having a hydroxyl group content calculated as polyvinyl alcohol of 8 to 25 wt. %, weight average molecular weight (Mw) between 10,000 and 500,000, preferrably 30,000 to 250,000, Daltons in amount in the coating composition of about 0.5 wt. % to about 25 wt. %, preferably 2 to 16 wt. %, based on the amount of binder resin.
In a more specific aspect a thermally activated curable liquid coating composition is provided comprising, in admixture:
a) crosslinking agent selected from alkoxymethylaminotriazines and polyisocyanates;
b) binder resin having functional groups coreactive with the crosslinking agent selected from the group consisting of acrylic resins, alkyd resins and polyester resins;
c) polyvinyl acetal matting agent containing acetal groups derived from one or more aliphatic or aromatic aldehydes having 1 to 10 carbon atoms; and
d) pigment colorant.
A further aspect of the invention provides an uncovered low gloss surface coating containing polyvinyl acetal matting agent in amount effective to produce a gloss reading of less than 60, preferably less than 15, using a glossmeter at an angle of sixty degrees to normal, which preferably contains crosslinked binder resin.
DETAILED DESCRIPTION OF THE INVENTION
Binder resin as used herein means organic polymer capable of forming a continuous adherent film on a substrate being coated. The organic polymer can be selected to react with a crosslinking agent during curing at elevated temperature to form a thermoset coating or be a non-crosslinkable high molecular weight thermoplastic material which, after drying removal of liquid such as solvent, forms a thermoplastic coating. Thermoplastic coatings do not contain crosslinking agent. Preferred binder resins used in high performance heat curable coatings contain functional groups coreactive with crosslinking agent and are selected from the group consisting of acrylic resins, alkyd resins, and polyester resins. These resins are particularly described in U.S. Pat. No. 5,079,315 issued Jan. 7, 1992 to Demarey, cols. 3, 4, 5 and 6, the content of which is incorporated herein by reference.
Commercially available examples of usable polyfunctional hydroxy group containing binder resins include JONCRYL® 500 acrylic resin, a product of S.C. Johnson & Sons, Racine, Wis.; ACRYLOID® AT-400 acrylic resin, a product of Rohm & Haas, Philadelphia, Pa.; CYPLEX® 1531 polyester resin, a product of Cytec Industries, West Paterson, N.J.; TONE® polyester resin, a product of Union Carbide, Danbury, Conn.; K-FLEX® XM-2304 and XM-2306 resins, products of King Industries, Norwalk, Conn.; CHEMPOL® 11-2339 and 18-2330 resin, a product of Cook Composites and Polymers, Port Washington, Wis.; JONCRYL® 540 acrylic emulsion polymer, a product of S.C. Johnson & Sons; RUCOFLEX® XR370 polyester resin from Ruco Polymer Corporation; RHOPLEX® AC-1024 acrylic emulsion resin, a product of Rohm & Haas; CRYLCOAT® 3494 solid hydroxy terminated polyester resin, a product of UCB Chemicals, Smyrna, Ga.; RUCOTE® 102 and 103 polyester resin, a product of Ruco Polymer Corporation, Hicksville, N.Y.; JONCRYL® SCX-800-A and SCX-800-B hydroxy functional solid acrylic resins, products of S.C. Johnson & Sons. Also, XC® 4005 water reducible carboxyl functional acrylic resin, a product of Cytec Industries.
Thermally activated curable coating compositions contain one or more crosslinking agents reactive with functional (e.g. hydroxyl) groups of the binder resin component of the composition at elevated curing temperatures. One class of crosslinking agents commonly employed in these reactions are the alkoxymethylaminotriazines which are methylated polyaminotriazines substantially etherified with one or more alcohols. They are prepared by reaction of polyaminotriazine with formaldehyde to methylolate at least about half the amino groups and are then alkylated or etherified by reaction with alcohol. The etherified methylolated aminotriazines are liquid and are essentially monomeric or at most oligomeric with an average degree of polymerization of no more than about 5, the aminotriazine rings being joined by methylene or methylene ether bridges formed by condensation of two methylol groups. Suitable etherified aminotriazines include those possessing a ratio of aminotriazine to combined formaldehyde in the range of about 1:(2n−3) to about 1:2n where n is the number of amino groups per triazine ring and a ratio of aminotriazine to alkyl ether groups in the range of about 1:(2n−3.5) to about 1:2n provided that on average there are at least about 1.8 alkoxymethyl groups per molecule. Melamine is a preferred aminotriazine which is potentially hexafunctional. Thus, the more preferred aminotriazine compounds are alkoxymethyl melamines in which the ratio of melamine to combined formaldehyde is in the range of 1:3 to 1:6 and the ratio of melamine to alkoxy groups is in the range of 1:2.5 to 1:6. Alcohols suitable for etherification of methylol melamine are branched or straight chain C
1
to C
8
alcohols. A mixture of alcohols such as methanol and butanol or methanol and isobutyl alcohol (2-methyl-1-propanol) can be used for etherification to make a mixed etherified amino resin. Preferred mixed ethers are methoxy/butoxy and methoxy/isobutoxy ethers. The range of the ratio of methoxy/butoxy or methoxy/isobutoxy can vary widely with about 2:1 to about 1:2 preferred. A single alcohol can also be used for etherification with methanol preferred. Aminotriazine crosslinkers are available commercially from Solutia, Inc. under the registered trademark Resimene.
Another class of crosslinking agents are polyisocyanates including blocked forms thereof which are generally well known and are extensively used in coating compositions in monomeric, oligomeric and/or polymeric form, preferably containing at least two reactive isocyanate groups. Specific examples are hexamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; meta-&agr;,&agr;,&agr;′,&agr;′-tetramethylxylylene-diisocyanate (commercially available under the trade designation m-TMXDI® aliphatic isocyanate from Cytec Industries Inc.); para-&agr;,&agr;,&agr;′,&agr;′-tetramethylxylylene-diisocyanate (available under the trade designation p-TMSDI® aliphatic isocyanate from Cytec Industries Inc.); 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate, abbreviated as IPDI); bis(4-isocyanatocyclohexyl)methane (hydrogenated MDI); biuret derivatives of various diisocyanates includin
Chen Augustin T.
Kestyn Paul E.
Zhao Hong
Aylward D.
Dawson Robert
Lathrop & Gage L.C.
Solutia Inc.
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