Polyvinyl acetate fillers

Lucie, S., Kovacevic, V., Packham, D.E., Bogner, A., Gerzina, A., Stearate-modified calcium carbonate fillers and their effect on the properties of polyvinyl acetate, composites. Proc. 2nd Int. Symp. Polymer Surface Modification Relevance to Adhesion, Newark, NJ, 24-26 May, 1999. 

A typical two package polyester cement consists of an unsaturated polyester (41), cellulose acetate butyrate or polyvinyl acetate (1.8) and N,N-dimethylaniline (1) dissolved in styrene (18). This liquid (binder) is intimately mixed with a filler consisting of graded silica or solid glass spheres (15.5), talc (23), titanium dioxide (1.0) and benzoyl peroxide (1.0). 

According to Hergeth and coworkers [55], a minimum surface of the inorganic particles is needed to prevent secondary nucleation. To estimate this amount, a formula was derived for seeded emulsion polymerization with spherical particles and a water-soluble initiator [55]. This formula was based on the observation that primary particles are produced by a coUapse and micellization process of oligomeric chains. An upper limit for the particle size was estimated to be 100 nm for the encapsulation of silica with polyvinyl acetate. A relatively water-soluble monomer is applied here for more hydrophobic monomers this upper limit will be higher. Because the surface area needed to prevent secondary nucleation is proportional to the monomer conversion per unit of time, the encapsulation efficiency can be improved by using monomer-starved conditions. So far, mainly submicrometer particles have been encapsulated with this method. The encapsulation of the larger filler particles... 

Uses Polyvinyl acetate for industrial coatings and wood fillers, e.g industrial luan plywood primers Features High pigment tolerance and exc. mech. stability Properties Emulsion 0.15 nm avg. particle size dens. 9.0 Ib/gal vise. 50-250 cps 48% solids Vinac A50 [Air Prods. Polymers Europe]... 

Chicle gum (Sapodilla tree latex), polyvinyl acetate, other natural latex s, including jelutong and rubber latex, filler (calcium carbonate)... 

PMMA was not the only type of polymer to be employed as a denture base material. Other synthetic polymers have also been introduced, including bakelite (phenol-formaldehyde) cellulose nitrate, nylon, epoxy resins, vinyl polymers (polyvinyl chloride and polyvinyl acetate) and polystyrene. Polycarbonates infiltrated with glass filler particles have also been used as denture based materials and, due to their filler content, have shown nine times higher impact properties than PMMA. Yet these materials have the disadvantage of more difficult molding than acrylics, since injection molding is required [97, 98]. 

The major part of the market for ceramic tile adhesives is held by formulations based on a filled polyvinyl acetate latex, but natural rubber latex is still used as a base, particularly where the adhesive is to perform under damp conditions. Formulations II and III give examples. Tile adhesives need to be stiffer than most other applications, and this effect is provided by the clay filler, which also reduces material costs and imparts gap filling properties. Cost may be further reduced by increasing the level of clay to 250 pphr, although performance will be reduced. The resin serves to improve bond strength and water resistance. 

Polyvinyl acetate emulsion adhesives can be compounded using very basic mixing equipment and procedures. Many resins, plasticizers, solvents, and fillers can be blended directly into the emulsion without preemulsifying or predispersing the additives. The ability to modify polyvinyl acetate with a wide variety of additives makes the adhesives more versatile and allows adhesion to a wider number of substrates than adhesives made from other resin bases. 

Many polyvinyl acetate emulsions can be used as adhesives without modification. However, an adhesive is usually compounded in order to tailor the product for a particular application. Compounding of adhesives facilitates application on equipment and bonding on specific substrates. It also imparts resistance to ambient conditions. In addition to film formers, an adhesive usually contains some of the following components plasticizers, viscosity/rheology modifiers, tackifiers/extenders, solvents, fillers, humectants, surfactants, and biocides. 

Clays and other fillers impart stiffness to adhesive films. Clays reduce the penetration of adhesives into porous substrates. Large-particle clays are better able to control penetration and also impart more rapid setting speed. A highly plastic clay, bentonite, makes adhesives thixotropic—fluid under high shear, thicker upon application. A study has been made of the effect of various fillers on the adhesive properties of polyvinyl acetate. 

Table 13 lists general purpose fillers than can be added to all polyvinyl acetate homo- and copolymer adhesive emulsions. 

Tales are sometimes used as fillers in polyvinyl acetate caulks, but the platy particles are not as easily dispersed as calcium carbonate. They do not have the same degree of whiteness and have higher oil absorption values with higher vehicle demand. They impart higher viscosities and thixotropy to the caulk. 

In emulsion adhesives and sealants, ionic and nonionic surfactants are used to disperse pigments and fillers. In polyvinyl acetate emulsion sealants, most grades of calcimn carbonate can be dispersed using anionie or non ionie surfactants. Titanium dioxide is more difficult to disperse due to its finer particle size ( 0.2pm) and anionic dispersants such as potassium tripolyphosphate and polymeric salts of acryhc acid are used. 

Attapulgite can be used in both water and solvent based adhesives and sealants to impart thixotropy, and good filler suspension. In water based polyvinyl acetate and vinyl emulsion systems, levels of 2 to 8 % are used. The attapulgite is easy to disperse and is usually added to the formula with the other dry components. The thixotrope also imparts good shelf stability,... 

Solvent-based synthetic resin flooring adhesives are still the most used floor adhesives and possess a dominant market position, despite the best efforts of the building professional society, which tried to reject them, because of their excellent processing characteristics. It is estimated that its market share is about 65-70%. They are made from solvent mixtures (such as methyl acetate, acetone, ethanol, and methanol), dissolved synthetic resins (polyvinyl acetate), and mineral fillers such as chalk. The solvent content is between 20% and 25%. Solvent-based synthetic resin flooring adhesives contain no water and, therefore, cause a relative slight swelling of the wood parquet. 

For the purpose of the swelling behavior, sensitive parquet formats with bright decoration, such as beech and maple, require the development of both water- and solvent-fi-ee reactive resin flooring adhesives. In addition to epoxy, resin adhesives used in Germany are mainly polyurethane adhesives. The environment-friendly way to glue flooring is undoubtedly the use of water-based dispersion parquet adhesives. These consist of polyvinyl acetate polymer dispersions and binders such as chalk and mineral fillers. 

Production of all types of vinyl resins, exclusive of plasticizers and fillers, during 1941 to 1950 are presented in Figure 2. These totals are for production of all polymers customarily classified as vinyl resins, including polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate or vinylidene chloride, or modified polymers derived from them. However, the principal monomeric raw material for this field of resins is vinyl chloride. 

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