Glue, white

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). 

Polyvinyl acetate is an ingredient in white glue. It is a copolymer with vinyl alcohol in latex paints. 

Hairspray is formulated to hold hair in place and keep it shiny, without flaking off, without failing, even in humid conditions. Yet it must retain the ability to be washed out of the hair easily for at least forty-eight hours, and it must not clog the spray can s nozzle. Complex polymers are needed to perform all of these tasks well. The basic building blocks of these polymers are the same ones found in acrylic paints and white glue. But they are put together in a different way. 

Of course, only easily available proteinaceous materials could be used in historical materials, particularly egg (whole or either yolk or white), glue (from bovine or porcine bones or skin, but also from rabbit or fish), gelatine, milk, curd, whey, and blood. In the following paragraphs the basic characteristics of the main groups of these proteins are... 

Zinc oxide occurs in nature as mineral zincite. It is the most important zinc compound and has numerous industrial applications. Zinc oxide is the pigment in white paints. It is used to make enamels, white printing inks, white glue, opaque glasses, rubber products and floor tiles. It is used in cosmetics, soaps, pharmaceuticals, dental cements, storage batteries, electrical equipment, and piezoelectric devices. Other applications are as a flame retardant, as a UV absorber in plastics, and a reagent in analytical chemistry. A major application of zinc oxide is in the preparation of most zinc salts. In medicine, the compound is used as an antiseptic, an astringent and a topical protectant. 

It s easy to stretch a layer of dried white glue until it splits in half, and it s easy to yank a single strand of sewing thread into two pieces. Combine the glue with many strands of thread, however, and the resulting composite is most resistant to breakage—but only in the directions parallel to the threads. Make this composite and test its strength. 

White glue, sewing thread, aluminum foil, scissors... 

Zinc oxide has a wide range of uses apart from its use as an artist s pigment where it provides a more translucent white than flake white or titanium white. It is used in cosmetics, driers, quick-setting cements with syrupy phosphoric acid or zinc chloride in dental cement in the manufacture of opaque glass, enamels, car tyres, white glue, matches, white printing inks and porcelain. The photophysics of zinc oxide has been reviewed.1468 ... 

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(vmyl acetate). This is also known as white glue. ... 

The polymer for this gel is common white glue (mostly poly[vinyl acetate]), crosslinked as above with borax. 

Measure about 45 mL of white glue into a 250 mL beaker. Add an equal amount of warm water and a few drops of food colouring. 

Poly(vinyl acetate) (PVAc), -[CH2-CH(OCOCH3) , is also prepared as an emulsion for adhesive applications, and is familiar to users as white glue. As mentioned already, the Tg of PVAc is above room temperature, which makes the polymer rigid and brittle at room temperature. For adhesive application, therefore, an external plasticizer, such as dibutyl phthalate, is added to lower the Tg below room temperature and to facilitate film formation from emulsions. 

Have students use lines of white glue to design a pattern or scene on the paper. 

So-called white glues are particularly important. The chemical basis is polyvinyl acetate (PVA), the bonded joints - or traditionally adhesive gluings - are characterized by very high adhesive strengths, which usually result in adherend fractions after destructive testing. In order to avoid possible tensions, it is recommended to let the bonded joint set under even pressure (clamp) for more than the indicated... 

Tri-Star. [Tri-Star] White glues and foam control agents. 

Polyvinyl acetate Common "white" glue Book bindings and labels... 

Figure 2. Static shear strength values for adhesive joints in deteriorated Doug-las-Jir made with AYAT, Acryloid B72, Butvar B98, and PVA emulsion ""white glue Key P, polar solvent N, nonpolar solvent. (Adapted from ref 21).

Di- -butyl phthalate is used in many products that are made from plastic. It is also in products like white glues and carpenter s glues made from a plastic known as polyvinyl acetate emulsion. Di- -butyl phthalate is also used in some paints, furniture lacquer, and nail polish. When it is in anything, di- -butyl phthalate is at a higher level when that product is new. There is less in products that are old. Because di- -butyl phthalate may be in some toys, there is a concern that children chewing on such toys might be exposed. No measurements have yet been made to show whether children are exposed in this way. 

The most important use of di- -butyl phthalate is as a plasticizer (Cadogan and Howick 1992, 1996). Plasticizers are compounds that are added to other substances in order to make them softer and more flexible (Cadogan and Howick 1996). Di- -butyl phthalate appears to be primarily used as a plasticizer in polyvinyl acetate emulsion adhesives (white glues and carpenter s glues, see Pocius 1991) as a solvent for... 

Products aud Uses A white pigment in paints, cosmetics, dental cements, white glue, matches, white printing inks, artists paints, and so on. Useful as a coloring agent, antiseptic, astringent, dietary supplement, UV (ultraviolet) absorber, and nutrient. 

Poly(vinyl acetate) latex is used in the production of water-based emulsion paints, adhesives, and textile and paper treatments. Emulsion paints are stable, dry quickly, and are relatively low cost. PVAC emulsion adhesives are used in labeling and packaging, and as the popular consumer white glue. Copolymers with dibutyl fumarate, vinyl stearate, 2-ethylhexyl acrylate, or ethyl acrylate are used to obtain compositions that are softer for emulsion use. As indicated above, a major use of poly(vinyl acetate) is in the production of poly(vinyl alcohol), which is itself the starting material for poly(viityl butyral) and poly(vinyl formal). 

The most common type of synthetic water-borne adhesives are based on vinyl acetate, and include the homopolymer, polyvinyl acetate and the copolymer with ethylene, ethylene vinyl acetate, the popular white glue. Copolymers with other monomers, such as acrylics, are increasing in use, particularly for adhesion to plastics. 

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