Poly emulsions, adhesion characteristics

In the emulsion pol)anerization products, poly(vinyl acetate) emulsion homopol aner and vinyl acetate based emulsion copol)aners have a great importance in industrial aspect as well as scientific aspect. They account for 28% of the total waterborne synthetic latexes. Poly(vlnyl acetate) emulsion homopol)aner was the first synthetic polymer latex to be made on a commercial scale [6-9]. Its production is growing steadily in both actual quantities and different applications. The largest volume applications are in the area of coating and adhesive. It offers good durability, availability at low cost, compatibility with other materials, excellent adhesive characteristic, and ability to form continuous film upon drying... 

Vinylidene Chloride Copolymer Latex. Vinyhdene chloride polymers are often made in emulsion, but usuaUy are isolated, dried, and used as conventional resins. Stable latices have been prepared and can be used direcdy for coatings (171—176). The principal apphcations for these materials are as barrier coatings on paper products and, more recently, on plastic films. The heat-seal characteristics of VDC copolymer coatings are equaUy valuable in many apphcations. They are also used as binders for paints and nonwoven fabrics (177). The use of special VDC copolymer latices for barrier laminating adhesives is growing, and the use of vinyhdene chloride copolymers in flame-resistant carpet backing is weU known (178—181). VDC latices can also be used to coat poly(ethylene terephthalate) (PET) bottles to retain carbon dioxide (182). 

Emulsion Polymerization. Poly(vinyl acetate) and poly(vinyl acetate) copolymer latexes prepared in the presence of PVA find wide appHcations in adhesives, paints, textile finishes, and coatings. The emulsions show exceUent stabiHty to mechanical shear as weU as to the addition of electrolytes, and possess exceUent machining characteristics. 

A very common copolymer of vinyl chloride is with vinyl acetate. Copolymerization with vinyl acetate improves stability and molding characteristics. The copolymers are also used as fibers and as coatings. Copolymers intended for use in moldings are usually prepared by suspension polymerization. Those intended for coating purposes are prepared by solution, emulsion, and suspension polymerizations. The copolymers used in molding typically contain about 10% poly(vinyl acetate). Copolymers that are prepared for coating purposes can contain from 10-17% poly(vinyl acetate). For coatings, a third comonomer may be included in some resins. This third component may, for instance, be maleic anhydride, in small quantities, like 1%, to improve adhesion to surfaces. 

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