Cellulose ester adhesives

Developments in cellulose ester adhesives and alkyd resin adhesives Cyclized rubber in adhesives (Fischer-Goodrich Co.)... 

Cellulosics. CeUulosic adhesives are obtained by modification of cellulose [9004-34-6] (qv) which comes from cotton linters and wood pulp. Cellulose can be nitrated to provide cellulose nitrate [9004-70-0] which is soluble in organic solvents. When cellulose nitrate is dissolved in amyl acetate [628-63-7] for example, a general purpose solvent-based adhesive which is both waterproof and flexible is formed. Cellulose esterification leads to materials such as cellulose acetate [9004-35-7], which has been used as a pressure-sensitive adhesive tape backing. Cellulose can also be ethoxylated, providing hydroxyethylceUulose which is useful as a thickening agent for poly(vinyl acetate) emulsion adhesives. Etherification leads to materials such as methylceUulose [9004-67-5] which are soluble in water and can be modified with glyceral [56-81-5] to produce adhesives used as wallpaper paste (see Cellulose esters Cellulose ethers). 

All of the eommereial alkyl eyanoaerylate monomers are low-viseosity liquids, and for some applications this can be an advantage. However, there are instances where a viseous liquid or a gel adhesive would be preferred, sueh as for application to a vertical surface or on porous substrates. A variety of viscosity control agents, depending upon the desired properties, have been added to increase the viscosity of instant adhesives [21]. The materials, which have been utilized, include polymethyl methacrylate, hydrophobic silica, hydrophobic alumina, treated quartz, polyethyl cyanoacrylate, cellulose esters, polycarbonates, and carbon black. For example, the addition of 5-10% of amorphous, non-crystalline, fumed silica to ethyl cyanoacrylate changes the monomer viscosity from a 2-cps liquid to a gelled material [22]. Because of the sensitivity of cyanoacrylate esters to basic materials, some additives require treatment with an acid to prevent premature gelation of the product. 

Plastic pellets, threat from, 20 231 Plastic pumps, for corrosive liquids, 21 76 Plastic refractories, 21 482 Plastics. See also Styrene plastics adhesion of coatings to, 7 91-92 advanced materials, 1 693 cellulose ester applications, 5 404 chemical exposure tests on, 19 583 citric acid application, 6 648 colloidal suspensions, 7 273t colorants for, 7 358-380 development of, 10 168... 

Uses Solvent for cellulose esters and resins in manufacturing of printing inks, nail polishes, polymerization and spinning of acrylonitrile, dyeing wool, polyvinyl chloride adhesives, esters, waxes, vegetable oils brake fluids solvent degreasing antiseptic organic synthesis. 

The advanced applications for nitrocellulose plastisol propellants require that they be integrally bonded to the motor case. Successful case bonding for the multiyear storage life of a rocket calls for special adhesives and liners which are completely compatible with these highly plasticized propellants. Best results have been obtained with a combination of an impervious rubber liner and a crosslinked adhesive system with a limited affinity for the plasticizers used in the propellants. Examples of effective liners are silica-filled butyl rubber and chlorinated synthetic rubber. Epoxy polyamides, isocyanate-crosslinked cellulose esters, and combinations of crosslinked phenol-formaldehyde and polyvinyl formal varnishes have proved to be effective adhesives between propellant and impervious liners. Pressure curing of the propellants helps... 

Heat-setting resins cannot be plasticized by low molecular weight plasticizers. Polyvinyl acetals have been claimed for these products. American Cyanamid Co. has suggested polyvinyl acetals or butyrals in an amount of 10 to 25% of the resin for urea and melamine resins. For varnishes and adhesives, combinations of phenolic resins and polyvinyl formal are recommended. Polyvinyl acetals with higher alkyl radicals are suitable for cellulose esters and improve elasticity as well as resistance against water. 

Coumarone-indene resins are sold under various trade names Cumar, Neville, Nevindene, Paradene Picoumaron. Numerous applications in industry include uses in plastics, protective coatings, adhesives, lacquers, and as plasticizers for cellulose esters vinyl resins Refs i) Beil 17, 56 [ 57.1 2) Kirk Othmer... 

Cellulose ethers are a wide-ranging family of cellulose derivatives, commonly used in the food and pharmaceutical industry. Methyl, ethyl and propyl cellulose esters are used as drilling aids in mining and as detergents. They are also used as coatings and adhesives in cosmetic and pharmaceutical products. 

Cellulose esters of butyric and propionic acids have limited adhesive use. However, cellulose caprate, having a refractive index near that of glass and good resistance to photochemical change, is a useful hotmelt optical cement for the manufacture of compound lenses. 

Cellulose constitutes a ubiquitous and renewable natural material that has great potential for chemical conversion into high-quality adhesive products. The resurrection of research and development of cellulose derivatives, such as cellulose esters and ethers, cellulose graft-copolymers, and cellulose polyblends, has instituted new avenues for adhesive applications. There is little doubt that new solvent systems for cellulose have created the potential of developing uniform cellulose products with superior properties for adhesive applications. 

Epichlorohydrin is usually prepared from propene and is mainly used in the manufacture of glycerol and epoxy resins. It is also used in the manufacture of elastomers, glycidyl ethers, cross-linked food starch, surfactants, plasticizers, dyestuffs, pharmaceutical products, oil emulsifiers, lubricants, and adhesives as a solvent for resins, gums, cellulose, esters, paints, and lacquers and as a stabilizer in chlorine-containing substances such as rubber, pesticide formulations, and solvents. 

Use Plasticizer for cellulose esters and plastics, adhesive and coating compositions, insecticide, termite repellent, denaturant in rubbing alcohol formulas, lacquers, flavoring. 

MAJOR USES Used in the manufacture of epoxy resins, glycerol, pharmaceuticals, agricultural chemicals, coatings, ion excheinge resins glycidyl esters insecticides textile chemicals adhesives plasticizers solvent for natural and synthetic resins, gums, cellulose esters and ethers, paints, varnishes and nail enamels and lacquers stabilizer in chlorine containing materials and an intermediate in the preparation of condensates with polyfiinctional substances. 

ORIGIN/INDUSTRY SOURCES/USES plasticizer in plastic products manufacturing and rubber materials plasticizer for cellulose ester resins, polystyrene resins, and vinyl resins dye carrier used for film, cables, and adhesives... 

OTHER COMMENTS used as an extraction solvent for fats, oils, and waxes used as a solvent for cellulose esters and ethers useful in metal degreasing and dry cleaning diluent in paints and adhesives refrigerant and heat-exchange liquid chemical intermediate in the manufacture of organic chemicals and pharmaceuticals, such as chloroacetic acid. 

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. 

The most important cellulose derivatives are cellulose esters and ethers. Cellulose esters are prepared by the reaction of an activated cellulose with the corresponding carboxyhc acid, acid anhydride, or acid halide. Esterification is taken to completion (triester) and then hydrolyzed back to the desired free hydroxyl content. Viscosity is controlled by holding the reaction at the acid stage until the molecular weight has been reduced to the desired level. For plastics, a relatively high molecular weight is desirable, while for applications as adhesives, lacquer, and hot melts, a much lower molecular weight is more suitable. 

Before the advent of synthetic resin adhesives, semisynthetic cellulosic materials were developed, but when they were first dissolved in solvents and used as an adhesive is not clear from the literature. Historically, the first thermoplastic synthetic adhesive (only partly synthetic) was the cellulose ester cellulose nitrate, often called nitrocellulose, and it is still one of the most important. Later, other esters such as the acetate were developed, as well as certain mixed esters [1, p. 295]. 

Adhesives derived from cellulose are used in a wide variety of applications that require an economical means for bonding porous substrates. Specific uses and formulations of various cellulose ester and ether adhesives are discussed in the following sections. 

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