Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From fluorine-containing reactant
Reexamination Certificate
2002-11-14
2003-06-17
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From fluorine-containing reactant
C528S299000, C528S300000, C528S301000, C528S302000, C528S307000, C528S308000, C525S437000, C525S443000, C522S078000, C522S179000
Reexamination Certificate
active
06579966
ABSTRACT:
FIELD OF INVENTION
This invention relates to laminates having improved cleanable stain resistance due to the incorporation of a polymer having repeat units from an oxetane monomer having pendant fluorinated groups into a stain resistant surface layer. The stain resistant layer can also be adhered to a variety of substrates including vinyl, polyesters, paper, polyolefins etc. The coatings can exhibit dry erase characteristics when dry erase markers are used. That is, the coating can be marked, but readily removed, (wiped dry) by a dry cloth, erasure, or the like.
More specifically, this invention relates polyester polymers including blocks of polyoxetane derived from polymerizing monomer or monomers including oxetane monomers with partially or fully fluorinated side chains. These polyesters have many of the desirable properties of fluorinated polymers and the ease of processability of the polyesters. The desirable properties of the fluorinated polymers are due to the fluorinated side chains and the tendency of the fluorinated side chains to be disproportionately present at the air-substrate interface. The polyester polymers containing one or more fluorinated polyoxetane or oxirane blocks are cured with an amino resin.
BACKGROUND OF INVENTION
U.S. Pat. No. 4,603,074 sets forth a polyester-amino resin composition that can form a stain resistant layer on plasticized polyvinyl chloride substrates. While this coating was very good with respect to stain resistance and abrasion resistance, it would be desirable to have further increases in cleanability, stain resistance, repellency, and some abrasion resistance.
A variety of polymeric coatings and surface treatments for natural and synthetic materials have been developed to enhance the dirt and stain release characteristics. Some of the more effective ones to date allow for reapplication of the anti-soil treatment after cleaning (such as with carpets) or in tents.
Dry erase boards and ink or marker pens are popular replacements for chalkboards. A variety of relatively nonporous writing surfaces have been developed along with special dry erase markers that are specially designed to leave strong well defined continuous marks that can be erased with a dry cloth or eraser. U.S. Pat. Nos. 3,834,823; 3,922,457; 3,949,132; 4,746,576; 4,988,123 and 5,324,764; disclose such technology and are herein incorporated by reference for their teachings on dry erase systems.
U.S. Pat. No. 5,650,483 describes the preparation of oxetane monomers useful to form oxetane polymers with pendant fluorinated chains. The oxetane polymers were characterized as having low surface energy, high hydrophobicity, oleophobicity and a low coefficient of friction. That patent is incorporated by reference herein for its teachings on how to prepare the oxetane monomers and polymers. In the reference the oxetane polymers could be formulated with isocyanates to form crosslinked compositions. Additional patents issued on variations of the oxetane monomers and polymers. These were U.S. Pat. Nos. 5,468,841; 5,654,450; 5,663,289; 5,668,250, and 5,668,251 also incorporated herein by reference.
SUMMARY OF INVENTION
According to the present invention, it was discovered that an amino resin cured polyester resin having low surface energy, high hydrophobicity and a low coefficient of friction, which can result in improved stain and abrasion resistance, was developed by incorporating a hydroxyl terminated polymer containing repeat units from an oxetane monomer, having pendant fluorinated groups thereon, into a polyester. The oxetane polymer can be a copolymer and have other repeat units such as derived from the ring opening polymerization of cyclic ethers including tetrahydrofuran, propylene oxide or epoxy (oxirane) monomers. A preferred method of incorporating the polyoxetane polymer or copolymer into the polyester is to react the polyoxetane with a dicarboxylic acid or anhydride thereof under effective conditions to result in a half ester linkage between the polyoxetane and the diacid along with carboxylic acid terminal groups. Thereafter additional polyester repeating units can be added by reacting, for example, in situ, the terminal carboxylic acid groups with at least one polyol or cyclic ether and at least one additional polyacid and/or anhydrides of a polyacid. As polyesters are known to undergo ester interchange reactions one could generically list the reactants used to form the polyesters as polyesters and their precursors.
The preferred oxetane monomer for this application is one with a single pendant —CH
2
—O—(CH
2
)
n
—Rf group where the Rf group is a partially or fully fluorinated linear, saturated or unsaturated, or branched alkyl of from 1 to 20 carbon atoms, and n is from 1 to 3 or 5.
Polyoxetanes with two pendant partially fluorinated groups per repeating unit could also be used with this technology. The terminology “partially fluorinated pendant group” will be used to describe the —CH
2
—O—(CH
2
)
n
—Rf group which is only partially fluorinated due to the CH
2
and —(CH
2
)
n
portions, that is, not every carbon atom contains the maximum number of fluorine atoms, or the carbon atom(s) is unsaturated.
One preferred embodiment is a layer of a flexible vinyl chloride polymer coated with said polyester-amino resin composition in solvent and heated to cure and adhere the resin to the vinyl chloride polymer layer with removal of the carrier, solvent or water. This provides the flexible vinyl chloride polymer layer or other substrate with a coating, e.g. dry erase which is stain resistant or which can readily be cleaned to remove stains without significant abrasion.
The vinyl chloride layer may be a vinyl chloride polymer, which is a plastisol coated and fused or is a plasticized vinyl chloride polymer composition which has been calendered or extruded. The vinyl chloride may be applied to a backing, substrate or support. In either case the polyvinyl chloride layer (about 1 to 30 or 100 mils thick) can be printed one or more times. The printed layer can be embossed, before and/or after printing, and finally coated with a layer of a solution of a said polyester-amino resin composition and cured to provide the vinyl chloride polymer layer with an outer stain resistant layer about 0.1 to 2 or 4 mils or more thick.
DISCUSSION OF DETAILS AND PREFERRED EMBODIMENTS
The reactive polyester-amino resin composition may be applied to a substrate (e.g. vinyl chloride polymer, polyester, cellulosic, polyolefin composition) directly (i.e. no intermediate layer) or with an intermediate tie layer to form for example, a dry erase coating. The substrate may be with or without a backing, with or without the printing, with or without decoration, and with or without embossing.
A preferred embodiment relates to the catalyzed reactive polyester-amino resin solution being directly applied to a substrate such as a polyvinylchloride plasticized polymer, polyester, etc., and subsequently cured and used as a dry erase coating surface layer.
The polyester resins are generally made by a condensation polymerization reaction, usually with heat in the presence of a catalyst, of a mixture of at least one polycarboxylic acid or its anhydride and a polyhydric alcohol. Reaction temperature generally range from about 110 to about 275, and desirably from about 215 to about 250° C. with suitable catalysts being such compound as dibutyl tin oxide and the like. Preferred polycarboxylic acids are the dicarboxylic acids and their anhydrides. Fatty monobasic oils or fatty acids, monohydroxy alcohols and anhydrides may be present. The polyester may contain active hydrogen atoms, e.g., carboxylic acid groups and/or hydroxyl groups for reaction with the amino resin or may contain unsaturation for crosslinking by another mechanism such as copolymerization with ethylenically unsaturated monomers. Examples of some acids to use to form the alkyd resin or reactive polyester are adipic acid, cyclohexane dioic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic anhydride, and so forth. Generally the ali
Gottschalk Daniel C.
Kresge Edward N.
Medsker Robert E.
Weinert Raymond J.
Woodland Daniel D.
Acquah Samuel A.
Burleson David G.
Hudak Daniel J.
Omnova Solutions Inc.
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