Adhesive PVAC

Uses Flame-retardant plasticizer for NBR elastomers, PVC (sheeting, coatings for apparel, upholstery, wall coverings, wire insulation, plastisols, adhesives), PVAc adhesives, acrylics., finished film or coated fabric applies., vinyl plastisols, ethyl cellulose, phenolics, PP, PS, NC, SBR and butyl rubbers, engineering resins, unsat. polyesters, alloys antiwear agent EP agent... 

As a furniture adhesive, PVAC is used for general assembly applications, film overlay and high pressure lamination, edge gluing, wood... 

Uses Surfactant, plasticizer, tackifier, thickener for aq. adhesives, PVAc adhesive dispersions, food-pkg. adhesives Reguiatory FDA 21CFR 175.105 Properties Liq. 100% act. 

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). 

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. 

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. 

Poly(vinyl acetate) emulsions are used to prime-coat fabrics to improve the adhesion of subsequent coatings or to make them adhere better to plastic film. Plasticized emulsions are appHed, generally by roUer-coating, to the backs of finished mgs and carpets to bind the tufts in place and to impart stiffness and hand. For upholstery fabrics woven from colored yams, PVAc emulsions may be used to bind the tufts of pile fabrics or to prevent sHppage of synthetic yams. 

In contrast to other polymers the resistance to water permeation is low due to the hydrolysis of the poly(vinyl acetate) (163,164). Ethylene copolymers have been developed which have improved water resistance and waterproofness. The polymer can be used in the latex form or in a spray-dried form which can be preblended in with the cement (qv) in the proper proportion. The compressive and tensile strength of concrete is improved by addition of PVAc emulsions to the water before mixing. A polymer-soHds-to-total-soHds ratio of ca 10 90 is best. The emulsions also aid adhesion between new and old concrete when patching or resurfacing. 

PVAc is another important type of adhesive, especially in furniture manufacturing and for carpentry. They form the bond line in a physical process by losing their water content to the two wooden adherends. PVAc adhesives are ready to use, have short setting time and give flexible and invisible joints. They are easy to clean and show long storage life. Limitations are their thermoplasticity and the creep behavior. 

Depending on the formulations various grades of water resistance can be achieved according to EN 204 (D1-D4) [172], For the two-component PVAc adhesives crosslinking and hence a duroplastic behavior is effectuated by addition of hardening resins (e.g. on basis of formaldehyde), complex forming salts (based... 

Plasticizers soften the film and increase the adhesion and the setting speed. The most common are phthalates, adipates and benzoates. The amount added can be in a broad range of 10-50%. They affect the swelling and softening of the PVAc emulsion particles, ensure film formation at room temperature, and the tack of the still wet adhesive. They also provide improved moisture resistance of the bond. Disadvantages are the lower resistance of the bond line against heat, possible migration of the plasticizers and enhanced cold flow. 

Fillers (calcium carbonate, calcium sulfate, aluminum oxide, bentonites, wood flour) increase the solid content of the dispersion. They are added up to 50%, based on PVAc. The purpose of the addition is the reduction of the penetration depth, provision of thixotropic behavior of the adhesive, gap filling properties and the reduction of the costs. Disadvantage can be the increase of the white point and a possible higher tool wear. 

European Noim EN 204, Water resistance of PVAc adhesives, 1992. 

Vinyl acetate is polymerized to poly(vinyl acetate), (PVAc), which finds use in adhesives and water-based paints. Some PVAc is hydrolyzed (reacted with water) to poly(vinyl alcohol) (PVA) for textile sizing, adhesives, and paper coatings. A substantial amount of U.S.-produced vinyl acetate is exported. Prior to 1970, almost all vinyl acetate was made from acetylene. Now none of it is. 

SEC-FUR is widely used for adhesive analysis [704,706]. Evaporative SEC-FUR has been used for the study of adhesives composed of a high-MW acrylic fraction, a medium-MW PVAc fraction, SBR in the low-MW fraction and a trace amount of dilaurylthiodipropi-onate (DLTDP) in the very low-MW region [706]. The suitability of a moving ZnSe window for SEC-FUR was demonstrated by analysing oligomers in a PS standard mixture [503]. 

The first synthetic polymers to be used as paint varnishes were acrylic and vinylic resins. Poly(vinyl acetate) (PVAc), commercialized under the name Mowilith by Hoechst and Vinylite by Union Carbide, has been used in conservation as an adhesive since 1932 and in 1937 it was proposed as a picture varnish by Stout and Cross [63]. PVAc was soon rejected as a varnish because, despite its light stability and good solubility in organic solvents, it demonstrated poor optical properties in terms of colour saturation and the tendency to pick up dirt due to its low glass transition temperature. 

Poly(vinyl acetate) (PVAc), 13 735 25 557 adhesives, 25 578-583 applications of, 10 514-517 chemical properties of, 25 565 colloidal suspensions, 7 275 commercial manufacture of, 25 606-608 as a concrete additive, 25 585-586 conversion to poly (vinyl alcohol), 25 608-610... 

PVAc is used in adhesives and coatings and is hydrolyzed producing water-soluble PVA (Equation 6.44). The PVA may be reacted with butyraldehyde to produce poly(vinyl butyral) used as the inner lining of safety glass. 

Thermoplastics A number of thermoplastics have been used as adhesives. Polyamides and copolymers of ethylene and vinyl acetate (EVA) are used as melt adhesives. Copolymers of methyl methacrylate and other monomers are used as adhesives in the textile industry. PVAc is often used in school glues. 

Soon afterwards, however, Wacker Qiemie developed methods for the large scale production of vinyl acetate monomer (VAM) and also overcame S3mthetic limitations in the production of PVAc from VAM [5, 6]. The resulting polymer PVAc was soon found to be suitable for use both as a binder and as a major component in adhesives. 

PVAc, PVA and PVB are used in a vast number of different applications [19]. The most common use of PVAc-based dispersions and dispersible polymer powders is in the construction and adhesives industry. The polymeric binders are used as... 

The most widely used polyvinyl acetal is polyvinyl butyrai (PVB). This transparent amorphous plastic is used as a plasticized polymer in the inner lining of safety windshield glass (Saflex). Because of the presence of hydroxyl groups, the commercial product, which is produced from 75% hydrolyzed PVAc, has a Tg of about 49 C and has excellent adhesion to glass. 

Uses. The uses of polytvinyl acetate) adhesive are packaging and wood gluing. PVAc copolymer adhesives are finding application in more diverse areas such as construction and adhesion to moie difficult to bond surfaces because of the range of adhesion and the flexibility that may be built into the polymer,... 

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