Adhesive PVAC dispersion

PVAc-dispersion with plasticizer, adhesive for laminating textile/textile and textile/paper, filling agent for textile finishing. 

PVAC dispersions continue to be used for paper as consolidants (Wachter, 1987) and adhesives, especially the VAE copolymers (Maynor and van der Reyden, 1989 Scheper, 2005). 

Furthermore, the stahflity of such dispersions is pH dependent. In fact, many of them (except PVAc dispersions) coagulate in neutral or acidic conditions, leading to the failure of the adhesive system. This can he avoided hy the addition of neutralizing agents such as ammonium hydroxide or alkali hydroxides with pH values in the range of 9-10. 

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

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. 

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. 

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... 

Uses Surfactant, emulsifier, pigment wetting agent/dispersant, color acceptance agent for industrial coating systems, esp. latex paints, and for solvent-borne architectural paints, printing inks, adhesives, latexes food pkg. adhesives defoamer in food-contact paper coatings Features Low-foam remedies defoamer-induced film defects suitable for PVAc, acrylics, S/B, PVC/PVdC, alkyds, HC resins, NC, PU, epoxy, polyesters... 

Uses Plasticizer, solvent for PVC, PVAc, PVB, PS, cellulosics, paints vehicle for pigment dispersions in food-pkg. adhesives food pkg. adhesives, coatings, paper, cellophane, rubber articles, textiles Regulatory FDA 21CFR 175.105,177,1200 Manuf./Distrib. Akdeniz KImya Aldrich Allchem Ind. Boehme Filatex ... 

Uses Plasticizer for cellulosics, PS, PVAc modifier for lacquers, hot-melt coating formulations, extrudable plastics film-former, pigment dispersant in cosmetics emulsifier, stabilizer in foods emulsion stabilizer for flavoring oils in nonalcoholic beverages emulsion stabilizer, clouding agent, modifying extender for film-former biopolymers in food-pkg. adhesives... 

Properties Dens. 1.25 m.p. 98 C flash pt. (COC) 260 C ref. index 1.577 Uses Piasticizer for PVC, PVAc, VCA, PS, cellulosics modifier for coatings pharmaceutical raw material film-former in cosmetics dispersant for cosmetics, pharmaceuticals in food-pkg. adhesives Regulatory FDA 21 CFR 175.105... 

Uses Emollient in cosmetics plasticizer for some cellulosics, PVAc, PVC, VCA, in food-pkg. adhesives, in food-contact coatings pigment wetting agent, dispersant fragrance solvent... 

Definition Disodium salt of the half ester of nonoxynol-10 and sulfosuccinic acid Properties Anionic Toxicology TSCA listed Uses Emulsifier, solubilizer, wetting agent, surfactant, dispersant, foam booster/stabilizer, surf. tens, depressant in PVAc acrylic emulsions, paints, textile emulsions pad-bath additive in food-pkg. adhesives Regulatory FDA 21CFR 175.105 Trade Name Synonyms Aerosol A-103 [Cytec Ind. http //www.c ec.com, Cytec Ind. BV] Fizul... 

Nevertheless, the adhesives formulated with PVAc-based polymer dispersions suffer from some drawbacks. Due to the high poly(vinyl acetate) thermoplasticity the adhesive joints obtained with PVAc-based formulations are sensitive to high temperatures and have a poor resistance to creep under static load. Moreover, the presence of poly (vinyl alcohol) (PVA), used as protective colloid in the emulsion polymerization phase, makes them also easily affected by both moisture and water. 

The PVAc formulations currently available on the adhesives market are rather complex systems comprising a poly(vinyl acetate) dispersion, a film forming promoter, a cross-linking agent and/or a hardener. The use of modified poly(vinyl acetate) dispersions generally requires a thermal treatment to obtain the best results and the use of a specific cross-linking comonomer, such as N-methylolacrylamide (NMA), may cause a lower shelf-life of adhesives as well as formaldehyde emissions. 

Mechanical properties, water and solvent resistance of the polymer films obtained from the water dispersions and tensile strengths of the adhesive joints were evaluated (entries 14-18, Table 6). These results were compared with those obtained for a formulation containing the PVAc homopolymer (entry 19, Table 6) and for a PVAc homopolymer/linseed oil blend (entry 20, Table 6). 

PVAc is usually synthesized as water dispersion, for use as an adhesive. 

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