Vinyl adhesive, production

TriaUyl Gyanurate Gure of Preformed Polymers. TAC and TAIC are often used in smaU amounts with vinyl-type and condensation polymers for cured plastics, mbber and adhesive products of high strength, and heat and solvent resistance. In some cases, chemical stabUity is also... 

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. 

Vinyl acetate is a dear colorless liquid. It has a boiling point of 72 °C and a flash point of -9 °C. In 1977 vinyl acetate production in the United States was 1.60 x 10 pounds (1 ). This gave vinyl acetate a rank of 45 among the 50 top-volume chemicals produced in the United States during 1977. The major end uses of vinyl acetate were adhesives (30 ), paints (20 ), textile finishes (15%), and paper coatings (10 ). Approximately 15 of the vinyl acetate produced was exported (2). 

In general, poly(vinyl acetate) production is located close to end use industries (textile mills, adhesive plants, etc). In the United States, small-voIume captive producers also contribute to the market. 

Tetrahydrofurfuryl alcohol (THFA) is used to prepare tetrahydrofurfuryl acrylate and methacrylate in transesterification reactions with lower acrylate esters. These reactive monomers are used in the formulation of ultraviolet light-curable adhesives, coating, paints, and printing inks. THFA is an effective coalescing solvent for latex paints and is used in epoxy resin formulations. The oleic acid ester of THFA is used as a plasticizer for vinyl resin products. The high solvency of tetrahydrofurfuryl alcohol for dyes permits higher dye... 

About 90% of vinyl acetate production is used to manufacture polyvinyl acetate (PVA), which is used to make white glue and other adhesives. Also, PVA Is hydrolyzed to polyvinyl alcohol for use as a water-soluble adhesive. In addition, polyvinyl alcohol Is used as a feedstock In the production of polyvinyl butyral which Is used as a clear adhesive to make laminated automotive safety glass. 

Prepared generally by ester interchange from polyvinylacelate (ethanoate) using methanol and base also formed by hydrolysis of the acetate by NaOH and water. The properties of the poly(vinyl alcohol) depend upon the structure of the original polyvinyl acetate. Forms copolymers. Used as a size in the textile industry, in aqueous adhesives, in the production of polyvinyl acetates (e.g. butynal) for safety glasses. U.S. production 1980... 

The principal end use of acetic acid is m the production of vinyl acetate for paints and adhesives... 

Most of the acetic acid is produced in the United States, Germany, Great Britain, Japan, France, Canada, and Mexico. Total annual production in these countries is close to four million tons. Uses include the manufacture of vinyl acetate [108-05-4] and acetic anhydride [108-24-7]. Vinyl acetate is used to make latex emulsion resins for paints, adhesives, paper coatings, and textile finishing agents. Acetic anhydride is used in making cellulose acetate fibers, cigarette filter tow, and ceUulosic plastics. 

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly(vinyl acetate)—poly(vinyl alcohol) copolymers formed by free-radical polymerization in an emulsion system. Poly(vinyl alcohol) is typically formed by hydrolysis of the poly(vinyl acetate). The properties of the emulsion are derived from the polymer employed in the polymerization as weU as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a coUoid protection system. The protective coUoids are similar to those used paint (qv) to stabilize latex. For poly(vinyl acetate), the protective coUoids are isolated from natural gums and ceUulosic resins (carboxymethylceUulose or hydroxyethjdceUulose). The hydroHzed polymer may also be used. The physical properties of the poly(vinyl acetate) polymer can be modified by changing the co-monomer used in the polymerization. Any material which is free-radically active and participates in an emulsion polymerization can be employed. Plasticizers (qv), tackifiers, viscosity modifiers, solvents (added to coalesce the emulsion particles), fillers, humectants, and other materials are often added to the adhesive to meet specifications for the intended appHcation. Because the presence of foam in the bond line could decrease performance of the adhesion joint, agents that control the amount of air entrapped in an adhesive bond must be added. Biocides are also necessary many of the materials that are used to stabilize poly(vinyl acetate) emulsions are natural products. Poly(vinyl acetate) adhesives known as "white glue" or "carpenter s glue" are available under a number of different trade names. AppHcations are found mosdy in the area of adhesion to paper and wood (see Vinyl polymers). 

Vinyl organosol coatings, which incorporate a high molecular weight thermoplastic PVC organosol dispersion resin, are extremely flexible. Soluble thermosetting resins, including epoxy, phenoHc, and polyesters, are added to enhance the film s product resistance and adhesion. 

The principal chemical markets for acetylene at present are its uses in the preparation of vinyl chloride, vinyl acetate, and 1,4-butanediol. Polymers from these monomers reach the consumer in the form of surface coatings (paints, films, sheets, or textiles), containers, pipe, electrical wire insulation, adhesives, and many other products which total biUions of kg. The acetylene routes to these monomers were once dominant but have been largely displaced by newer processes based on olefinic starting materials. 

Attempts have been made to use cold-set adhesives in the cormgating operation, such as poly(vinyl acetate) and modified, precooked starch formulations, but these have not achieved any appreciable degree of commercial acceptance (20). The use of a polyethylene film appHed to the inside surface of the linerboard facing, which serves as a hot-melt cormgator adhesive, has achieved some commercial usage. However, its use is limited to the small, specialty product niche of fast-food hamburger cartons (see Olefin polymers, polyethylene). 

The adhesives (qv) used to form tube seams and bag bottoms include unborated dextrin, borated dextrin, casein, latex—casein, latex, poly(vinyl acetate), vinyl acetate copolymers, and hot-melt materials (10,27). Dextrin and casein adhesives are more commonly used in the production of grocery sacks vinyl acetate-type adhesives are commonly used in ah paper multiwah bags. The hot-melt adhesives are typicahy used to tack the phes of the multiwah bag together and to form the seam and bottom joints when polymer film phes or coated paper phes are used in bag constmction. 

The seam closure on a folding carton is typicahy made using a latex, poly(vinyl acetate), vinyl acetate copolymer, or hot-melt adhesive (27). The choice of adhesive depends on a number of factors, including the nature of any coating used on the package and the production speeds required. 

Small amounts of TAIC together with DAP have been used to cure unsaturated polyesters in glass-reinforced thermo sets (131). It has been used with polyfunctional methacrylate esters in anaerobic adhesives (132). TAIC and vinyl acetate are copolymerized in aqueous suspension, and vinyl alcohol copolymer gels are made from the products (133). Electron cure of poly(ethylene terephthalate) moldings containing TAIC improves heat resistance and transparency (134). 

Vinyl acetate [108-05-4] (VAc), CH2=CHOOCCH2, the ethenyl ester of acetic acid, is primarily use for the manufacture of poly(vinyl acetate) [9003-20-7] (PVAc) and vinyl acetate copolymers. Poly(vinyl acetate) homo- and copolymers are found as components in coatings, paints and sealants, binders (adhesives, nonwovens, constmction products, and carpet-backing), and miscellaneous uses such as chewing gum and tablet coatings. AppHcations have grown over the years in a number of areas (1 4). 

Poly(ethyl methacrylate) (PEMA) yields truly compatible blends with poly(vinyl acetate) up to 20% PEMA concentration (133). Synergistic improvement in material properties was observed. Poly(ethylene oxide) forms compatible homogeneous blends with poly(vinyl acetate) (134). The T of the blends and the crystaUizabiUty of the PEO depend on the composition. The miscibility window of poly(vinyl acetate) and its copolymers with alkyl acrylates can be broadened through the incorporation of acryUc acid as a third component (135). A description of compatible and incompatible blends of poly(vinyl acetate) and other copolymers has been compiled (136). Blends of poly(vinyl acetate) copolymers with urethanes can provide improved heat resistance to the product providing reduced creep rates in adhesives used for vinyl laminating (137). 

Growth in PVAc consumption is illustrated in Eigure 3. The emulsions continue to dominate the adhesives and paint markets. It also shows the distribution of PVAc and copolymer usage by market. The companies Hsted in Table 10 are among the principal suppHers of poly(vinyl acetate)s and vinyl acetate copolymers, but there are numerous other suppHers. Many other companies produce these polymers and consume them internally in the formulation of products. 

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