Ethylene vinyl acetate, adhesives

Suspension Polymerization. At very low levels of stabilizer, eg, 0.1 wt %, the polymer does not form a creamy dispersion that stays indefinitely suspended in the aqueous phase but forms small beads that setde and may be easily separated by filtration (qv) (69). This suspension or pearl polymerization process has been used to prepare polymers for adhesive and coating appHcations and for conversion to poly(vinyl alcohol). Products in bead form are available from several commercial suppHers of PVAc resins. Suspension polymerizations are carried out with monomer-soluble initiators predominantly, with low levels of stabilizers. Suspension copolymerization processes for the production of vinyl acetate—ethylene bead products have been described and the properties of the copolymers determined (70). Continuous tubular polymerization of vinyl acetate in suspension (71,72) yields stable dispersions of beads with narrow particle size distributions at high yields. 

Film and foil adhesives based on internally plastici2ed copolymer adhesives have been suggested. For instance, vinyl acetate—ethylene or vinyl acetate—acrylate copolymers may be used for adhesion of films to porous surfaces. For metallic foil adhesion, copolymers containing carboxylate functionahty are suggested. 

Anhydride modified ethylene promoter (20) vinyl acetate resin, adhesion... 

H. Okazaki and T. Ohkubo, Vinyl acetate-ethylene copolymer emulsion and aqueous emulsion adhesive composition containing the emulsion, US Patent 4446274, assigned to Denki Kagaku Kogyo Kabushiki Kaisha (Tokyo, JP), May 1,1984. 

Vinyl Acetate-Ethylene. Materials based on copolymers of vinyl acetate and ethylene exhibit a good balance of properties. As the ratio of vinyl acetate to ethylene is increased the copolymers become softer, more hydrophilic, and offer enhanced adhesion. However, at the highest levels of vinyl acetate the films become hard again, showing good adhesion to substrates such as wood and paper but with resistance to water somewhat inferior to that of the intermediate copolymers. 

Use Polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, and polyvinyl chloride-acetate resins, used particularly in latex paints, paper coating, adhesives, textile finishing, safety glass interlayers. A vinyl acetate-ethylene copolymer is available for specialty products. 

Aqueous dispersions of poly(vinyl acetate) and vinyl acetate-ethylene copolymers, homo- and copolymers of acrylic monomers, and styrene-butadiene copolymers are the most important types of polymer latexes today. Applications include paints, coatings, adhesives, paper manufacturing, leather manufacturing, textiles and other industries. In addition to emulsion polymerization, other aqueous free-radical polymerizations are applied on a large scale. In suspension polymerization a water-irnrniscible olefinic monomer is also polymerized. However, by contrast to emulsion polymerization a monomer-soluble initiator is employed, and usually no surfactant is added. Polymerization occurs in the monomer droplets, with kinetics similar to bulk polymerization. The particles obtained are much larger (>15 pm) than in emulsion polymerization, and they do not form stable latexes but precipitate during polymerization (Scheme 7.2). 

Useful film-forming resin adhesives include polyvinyl esters and ethers and their copolymers and interpolymers with ethylene and vinyl monomers, acrylic resins and their copolymers, polyvinyl alcohol, water dispersion of polyolefin resins, polystyrene copolymers such as polystyrene butadiene, polyamide resins, natural rubber dispersions, and natural and modified carbohydrates (starch or carboxycellulose). Particularly preferred for use are aqueous dispersions of polyvinyl acetate and vinyl acetate-ethylene copolymers. 

While a substantial proportion of emulsion adhesives are based on PVA, copolymer emulsion adhesives based on vinyl acetate ethylenes (VAEs) are becoming of increasing significance and... 

Poly (vinyl acetate) was used as a solvent-based adhesive in the 1930s, and later as a hot melt, but was not of commercial importance until its introduction in the 1940s, as an emulsion adhesive used mainly to bond paper and wood. Today, in emulsion form as a white glue, it is the most widely used thermoplastic adhesive worldwide. Vinyl acetate-ethylene (VAE) emulsion adhesives, with over 55% vinyl acetate content, were developed in the early 1950s but did not become of commercial importance in the United States until the mid-1960s. 

Anhydride modified ethylene vinyl acetate resin, adhesion promoter ... 

Synonyms Vinyl acetate-ethylene-vinyl chloride copolymer Vinyl chlo-ride/ethylene vinyl acetate copolymer Uses Binder, vehicle for emulsion paints, paper coatings, textured finishes, fabric coatings, flame retardant fabrics, constmction adhesives, and thermal insulation systems adhesive for flooring, walls, foam, tiles, paper/paperboard binder for fabrics, glass fiber textile auxiliary and coating paper coatings... 

Vinyl acetate/ethylene/vinyl chloride terpolymer adhesive, flour Styrene/PVP copolymer adhesive, foam... 

Acrylates copolymer Epoxy, bisphenol A 2-Hydroxyethyl acrylate Hydroxypropyl acrylate Meroxapol 105 Meroxapol 108 Meroxapol 171 Meroxapol 172 Meroxapol 174 Meroxapol 178 Meroxapol 251 Meroxapol 252 Meroxapol 254 Meroxapol 255 Meroxapol 258 Meroxapol 311 Meroxapol 312 Meroxapol 314 Methacryllc acid Methyl hydroxyethylcellulose PEG-14M PEG-2 stearate PEG-2 tallowate Polyethylene , Styrene/acrylates copolymer binder, textiles adhesives Hydroxypropyl methacrylate binder, textured coatings Vinyl acetate/butyl acrylate copolymer binder, textured finishes Vinyl acetate/ethylene/vinyl chloride terpolymer... 

Acrylonitrile-butadiene rubber, NBR, styrene-aciylonitrile rubber, SAN, ethylene-vinyl acetate copolymer, EVA, and acrylic copolymers are helpful modifications of polyvinylchloride that change its processing characteristics and elastomeric properties. Blending with these copolymers helps to reduce the requirement for low molecular weight plasticizers. Ethylene-vinyl acetate copolymer plays a role of high molecular weight plasticizer in production of vinyl hose. This reduces the amount of DOP used in flexible hose applications. Ethylene copolymer is used plasticize PVC that reduces gel. "" Phthalate plasticizers can be eliminated from water based adhesives because of utilization of vinyl acetate ethylene copolymer as a high molecular plasticizer/modifier. " ... 

For lamination, waterborne adhesives have actually been used in manufacturing flexible packaging and industrial laminates (91). Other latexes used besides acrylic are vinyl acetate, ethylene-vinyl acetate, vinylidene chloride, etc. The flexible packaging systems using these adhesives are PVDG-Gello/LDPE, OPP/OPP,... 

Copolymers, as the name implies, are produced from the polymerization of two different materials. Probably one of the most widely used copolymer emulsion adhesives is that based on vinyl acetate ethylenes, commonly referred to as VAEs (see Ethylene vinylacetate copolymers). These are produced by the copolymerization of vinyl acetate and 10-20% ethylene, the resulting polymer base possessing some superior properties over the PVA-based emulsions referred to above. These superior properties relate principally to the increased inherent flexibility of the dry VAE film due to the internal plasticization effect of the ethylene component in the polymer, which enhances adhesion to many difficult surfaces. There are, however, a number of other polymers and copolymers that are used as the formulating basis for alternative specialized emulsion adhesive systems. 

The compositions in this article are expressed as percentages by weight.) Bulk polymerization is widely used for polymers of 40-50% VA, and an emulsion process for those over 60% VA. In the intermediate range (15-60%), solution polymerization may be used. Both low (10-40%) and high (60-95%) VA materials have adhesive applications, the former as Hot melt adhesives, the latter as emulsion adhesives (see Emulsion and dispersion adhesives). The term vinyl acetate-ethylene is sometimes used to describe the copolymers rich in VA. 

This versatile technique is generally used where a ply of polyethylene or copolymer thereof is required in a structure. Other polymers may be used in specialized areas but the handling can become more difficult. The process is widely used within the Packaging Industry for the coating of paper, board, foils, cellulose film and thermoplastic films. The most common coating resin used is low-density polyethylene, but this now extends to copolymers such as Ethylene-vinyl acetate, ethylene-acrylic acid, polypropylene, high density polyethylene and ionomers (e.g. Surlyn). The acrylic acid-based materials and ionomers are used in areas in which enhanced adhesive strength is required, such as resistance to difficult environments. 

Makers of resin emulsions are attempting to boost prices in response to rising raw material costs. Air Products Polymers led the increase by announcing that it will raise the prices of its vinyl acetate ethylene, vinyl acrylic, polyvinyl acetate and ethylene vinyl chloride emulsions sold in the US and Canada by 2 cents per wet pound on July 1. PVA and EVA demand in adhesives markets are expected to be steady for the rest of the year. 

Adhesives for Plastic Floor Covering. Solvent-free adhesives based on acrylic and vinyl acetate - ethylene - acrylic emulsions are used for bonding vinyl, synthetic rubber, and polyolefin flooring. Solvent-containing contact adhesives (rubber- or polychloro-prene-based) still are used for some applications (e.g., stairs). When water resistance is required, reactive polyurethane or epoxy resin adhesives are preferred to waterborne emulsions. 

Ward and Kelley [9] have reported several means of incorporating the barrier properties of polyvinylidene chloride (PVDC) into packaging structures by taking advantage of the E/CO s excellent adhesion of PVDC. That adhesion was said to be unique among the polar ethylene copolymers widely used in packaging film constructions (e.g. ethylene vinyl acetate, ethylene acrylic acid). 

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