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
2000-03-09
2002-06-18
Wu, David W. (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...
C526S287000, C526S288000, C526S310000, C526S911000, C526S923000
Reexamination Certificate
active
06407162
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved emulsion polymerization process utilizing ethylenically unsaturated amine salts of sulfonic, phosphoric and carboxylic acids. More specifically, the invention relates to emulsion polymerization processes which utilize ethylenically unsaturated amine salts of alkylbenzene sulfonic acids, alkyl olefin sulfonic acids, alkyl alcohol sulfuric acid esters, or alkoxylated alkyl alcohol sulfuric acid esters, fatty acids, and fatty phosphate acid esters, or mixtures thereof, to form polymers, discrete solid polymeric particles and latexes. Additionally, the present invention relates to the use of the salts to impart improved adhesion, hydrophobicity, resistance to film yellowing, scrubability, anti-blooming, hydrolytic stability and shear stability characteristics to polymer emulsions and latex formulations.
2. Description of the Related Art
The emulsion polymerization of ethylenically unsaturated monomers to form discrete solid polymeric particles for use in coating, sealant, adhesive and/or elastomer (CASE) applications is well known to the art. Conventional emulsion polymerization of ethylenically unsaturated monomers employs one or more water soluble surfactants to emulsify the monomers and the resulting polymer products, i.e., latexes. The monomers used in emulsion polymerization reactions are generally water-insoluble, but in some cases may be water-soluble. During a typical emulsion polymerization, a surfactant is used to suspend small portions of monomer in a continuous or semi-continuous aqueous phase. Typically, the monomer molecules are suspended as small spheres in the aqueous phase, wherein the polymerization takes place within the small spheres. The water soluble surface active agents, i.e., surfactants, typically utilized in emulsion polymerization reactions are anionic, nonionic, and cationic surfactants or a mixture thereof.
The polymeric particles formed by the emulsion polymerization process are typically utilized in coating, sealant, adhesive and/or elastomer (CASE) applications. In a traditional emulsion polymerization reaction, the surfactant does not become chemically bonded to the polymeric particles by carbon-carbon bond formation but rather remains in the polymeric particle product solution after the emulsion polymerization reaction is complete, i.e., all of the monomer(s) is reacted. The unreacted surfactant can have a detrimental effect on the polymer product solution, as it can interfere with the performance of such polymerization products in CASE applications; the suspension of polymeric particles may become destabilized over time and undergo unwanted coagulation. The unreacted surfactant may cause unwanted pealing of a latex paint coating on a substrate, and decreased moisture and scrubability resistance in other various CASE applications. Additionally, residual surfactant can cause an undesirable “blooming” that leads to surface irregularities in a resulting CASE material that is applied to a substrate.
Several proposals have been made in the prior art to employ a polymerizable surfactant as the surface active agent during an emulsion polymerization reaction. U.S. Pat. No. 5,478,883 (incorporated herein by reference in its entirety) describes the use of ethylenically unsaturated polymerizable water-soluble nonionic surfactants formed by the reaction of a diallylamine compound with ethylene oxide, propylene oxide or butylene oxide, in emulsion polymerization reactions. Similarly, U.S. Pat. No. 5,162,475 (incorporated herein by reference) provides alpha-beta ethylenically unsaturated poly(alkylenoxy) polymerizable surface active compounds for use in emulsion polymerization. For additional examples of polymerizable surfactants for use in emulsion polymerization processes, see U.S. Pat. Nos. 4,377,185 and 4,049,608.
Non-polymerizable surfactant solutions to the traditional problems encountered in performing an emulsion polymerization process are numerous. U.S. Pat. No. 3,941,857 describes the use of epoxy resins which react with the residual anionic, cationic or nonionic surfactant. Polymerizable compounds such as allyl alcohol (and esters thereof) have been found to be ineffective due to the formation of undesirable high levels of coagulum in the final emulsion polymerization product. Additionally, see U.S. Pat. No. 4,224,455.
Thus, there is a need for an emulsion polymerization process for forming polymers and discrete polymeric particles that are well suited for use in coatings (e.g., latex paints, electro-deposition, container, paper and paperboard, can coatings, industrial coatings, automotive coatings, textile coatings), adhesive (e.g., water- and non-water borne adhesives, pressure sensitive adhesives, binders), sealant (e.g. floor finishes, films, binders, non-woven binding materials such as carpet backing, glass fibers) and elastomer (CASE) applications.
SUMMARY OF THE INVENTION
The present invention utilizes a novel group of compounds in the form of ethylenically unsaturated amine salts of sulfonic, phosphoric and carboxylic acids, which display surface activity, i.e. they are surfactants. It has been discovered that these compounds function as reactive surfactants, i.e. surface active agents in polymerization processes, particularly emulsion polymerization processes. The surface active agents of the present invention are capable of polymerizing with themselves (to form homopolymeric surface active agents) and/or are capable of co-polymerizing with other ethylenically unsaturated monomers of the type which are commonly employed in polymerization processes. The polymerizable surface active agents utilized in the present invention are prepared from readily available, economical raw materials, and generally, their preparation does not require any special handling or equipment.
Accordingly, an improved method is provided for forming polymers utilizing polymerizable surface active agents detailed herein. Generally, the improved method comprises:
a) preparing a mixture comprising:
i) at least one ethylenically unsaturated monomer;
ii) at least one polymerizable, surface active agent;
wherein the polymerizable, surface active agent is a salt or quaternary nitrogen compound comprising:
a) at least one acid, wherein the acid is a sulfonic acid, a carboxylic acid, or a phosphoric acid, or a mixture thereof; and
b) at least one nitrogenous base, wherein the nitrogenous base contains at least one nitrogen atom and at least one ethylenically unsaturated moiety; and
b) polymerizing the mixture;
wherein the polymerizable, surface active agent is capable of polymerization with itself, copolymerization with the ethylenically unsaturated monomer or co-polymerization with a partially polymerized polymer particle. Somewhat preferably, the nitrogen atom is linked covalently, directly or indirectly, to the ethylenically unsaturated moiety of the nitrogenous base.
The polymers prepared utilizing the polymerizable surface active agents of the present invention may be used as the primary resin component or a minor resin component of a resin mixture which is used to prepare latexes, coatings, adhesives, sealants, elastomers, binders, inks, floor finishes and the like. A polymer is defined herein as a product produced by polymerizing two or more monomers, which may be the same or different. Additionally, the polymer may have incorporated into it, surface active agent monomers and/or homopolymeric surface active agents. The various final compositions, application and polymer products described herein may contain various optional ingredients such as fillers, pigments, colorants, solvents, plasticizers, antioxidants, curing agents, thickeners, non-polymerizable surface active agents (surfactants), preservatives, wet strength additives, and the like.
The present invention provides an improved polymerization process for forming polymers, wherein the polymerizable surface active agent used in the polymerization reaction does not interfere with the quality of the CASE app
Schultz Alfred K.
Siddiqui Adnan
Egwim Kelechi C.
McDonnell & Boehnen Hulbert & Berghoff
Stepan Company
Wu David W.
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