Cellulose-based adhesives, plasticizers

Among other plasticizers, o- and p-toluene-sulfonamides are used to improve the processibility of urea and melamine resins, and cellulose-based adhesives. For the same reason, N-ethyl-o-toluenesulfonamide and N-ethyl-p-toluenesulfonamide are used for polyamides, casein, and zein. 

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly (vinyl acetate)—polytyinyl 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 well as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a colloid protection system. The protective colloids are similar to those used paint (qv) to stabilize latex. For poly (vinyl acetate), the protective colloids are isolated from natural gums and cellulosic resins (carboxymethylcellulose or hydroxyethylcellulose). The hydrolized 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 application. 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. Applications are found mostly in the area of adhesion to paper and wood (see VlNYL POLYMERS). 

OTHER COMMENTS used as a flame retarder and plasticizer in chlorinated rubber, nitrile rubber and resins used in coatings and adhesives based on plasticized cellulose esters used as a gasoline additive to control pre-ignition useful as a solvent in the extraction of phenol fi om gas-plant effluents and coke-oven wastewaters use as a synthetic lubricant, a waterproofing agent, a primary component of adhesives, and as an intermediate in the synthesis of pharmaceuticals. 

In nature the enzymes are able to convert cheap feedstocks such as sugars and amino acids into a large variety of functional and structural polymers with very high complexity. For many years, biopolymers such as starch, dextrose, cellulose, shellac, casein plastics, and proteins were used as polymers from renewable resources to formulate adhesives [9]. The life sciences effort is promoting the development of new processes based upon biotechnological routes to carbo-... 

Dibutyl phthalate (DBP) is not convenient for PVC plasticization because of its relatively high volatility. It is a good gelling agent for PVC and vinyl chloride-vinyl acetate copolymer (PVCA) and so is sometimes used as a secondary plasticizer in plasticizer mixers to improve solvation. DBP is mainly used for cellulose-based varnishes and for adhesives. It has a high dissolving capacity for cellulose nitrate (CN). 

Chem. Descrip. Wh. mineral oil DSP CAS 8042-47-5 EINECS/ELINCS 232-384-2 Uses Plasticizer for ethyl cellulose base in cosmetics (creams, lotions, sunscreens), pharmaceuticals (laxatives), foods (lubes/greases, food pkg.), plastics (lubes for PS, PVC, annealing, catalyst carriers), adhesives protective coating on foods... 

Chem. Descrip. Tribulyl phosphate CAS 126-73-8 EINECS/ELINCS 204-800-2 Uses Flame retardant, plasticizer for nitrocellulose, cellulose acetate, chlorinated mbber. and vinyls antifoam for paper coalings, water-based adhesives, inks, textile sizes, detergent sol ns. high boiling solv. for lithographic inks latex paints also suitable for epoxy, PS, PVAc Prqietties Colorless liq. sp.gr. 0.980 (20/20 C) vise. 6 mPa s 11.7% P Phosflex 61B [AkzoNobeQ... 

These adhesives are compatible with a wide range of wood and wood-associated materials such as the common laminated plastics sheets and are effective on absorbent protein-based and cellulose- based materials, but unsuitable for thermoplastics. Almost invariably one surface must be absorbent. 

Biocides are widely used to protect wood. They should easily penetrate the wood and chemically interact with the cellvdose component, but not affect its adhesive properties. The fact that wood requires protection against microorganisms leads us to the observation that cellulose based plastics are among the synthetic materials most vulnerable to biodegradation. 

One of the drawbacks to solvent-based adhesives based on rigid polymers is the shrinkage that results when the solvent evaporates. This can set up stresses that weaken the joint. An example of this type of adhesive is the familiar model airplane cement, basically a cellulose nitrate solution, with perhaps some plasticizer. Rubber cements, of course, maintain their flexibility, but cannot support as great a stress. Commercial mbber... 

With regard to starch adhesives, the bulk of development is expected to come from thermoplastic starches that can be used as hot-melt adhesives or transformed into waterborne dispersions. For other plant derivatives such as soy and castor oil, a significant development effort is taking place in the manufacture of polyols for use primarily in polyurethane adhesives and sealants. Similarly, derived waxes are also being used as plasticizers in hot-melt adhesive formulations. For natural adhesives that are based on cellulose derivatives, tree resins and their by-products, as well as natural rubber, low growth rates are envisaged, whereas the market for advanced bio-based adhesives is stiU in the early stages of development. 

Two other filtration modules, which both formed part of automated radioimmunoassay systems, have been developed. - One of these, was based on conventional continuous flow techniques. At the filtration stage, a continuously moving strip of glass fiber filter paper was strengthened and wetted, the reaction mixture was filtered, and the precipitate was washed by two streams of buffer. The strip was dried and overlaid with cellulose adhesive tape before being counted as it passed between two end-window radioactivity detectors and wound onto a take-up spool. In the second system, glass fiber filter disks are mounted at intervals over perforated segments of a flexible plastic carrier tape. The contents of five... 

WPCs, based on polyolefins, have one principal problem related to their integrity It is commonly a blend of a hydrophobic plastic and hydrophilic wood (or hydrophilic cellulosic fiber). Hence, the adhesion between them is poor, the interface between plastic and wood filler is typically weak, and it fails to optimally transfer stress between the two phases, when loaded. Lubricants help to solve the problem however, there are means to further improve bridging the interface by employing other mechanisms. 

Melt-sprayed coatings have ethyl cellulose, acetyl cellulose or cellulose ace-tobut3Tate as a film-forming base. Mineral oil, which dissolves a number of Cl of ferrous and nonferrous metals and is perfectly compatible with the majority of cellulose plasticizers, is often introduced into the molten composition to lower adhesion of the coating to the goods being protected. 

The largest use of cellulose nitrate is as a base for lacquers and cements. Butyl acetate is used as a solvent. Plasticizers such as dibutyl phthalate and tritolyl phosphate are necessary to give films of acceptable flexibility and adhesion. 

Dichloromethane is used as a noncombustible solvent and extractant for oils, fats, waxes, fish oil, etc. from industrial and animal products, as well as caffeine, hops, castor oil, cocoa butter, and ethereal oils from substances of plant origin. It is used in the deparaffination of petroleum and the azeotropic dewatering of solvents. Dichloromethane is a constituent of paint-removal pastes and baths, but is increasingly being replaced by aqueous systems. It is used as a solvent in the production of cellulose-acetate-based or cellulose-acetobutyrate-based films and is employed industrially in the leather, metal, rubber, adhesives, and plastics industries. 

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