Cellulose ether adhesives

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). 

Cellulose is also commercially modified by acetylation to produce a material suitable for X-ray and cine film. Commercially cellulose ethers are also prepared, such as methylcellulose. This material is water-soluble and gives a highly viscous solution at very low concentrations. Hence it is widely used as a thickener in latex paints and adhesives, in cosmetics and for coating pharmaceutical tablets. 

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 is an old polymer with new industrial applications. The derivatization of cellulose has opened up tremendous production and marketing possibilities for the adhesives industry. Various important adhesives have been derived from cellulose ethers. The structure and molecular size of cellulose and their influence on swelling and solubility are important considerations in the preparation of cellulose derivatives for adhesive applications. Modern cellulosic adhesives derived from grafted copolymers and polyblends are also proving very useful. 

Table VI. Important Cellulose Ethers Used in Adhesive Applications...

In general, these groups of cellulose ethers have been used for their innate adhesive properties and to provide thickening to adhesive formulations. They are used for plywood adhesives, industrial adhesives, wallpaper paste, library paste, and latex adhesives. For example, methylcellulose is used in some adhesives as an additive to control viscosity, especially in the heat-cure phenol-formaldehyde glues and other hot-pressing adhesives. Hydroxyethylcellulose is used as an ingredient in polyvinyl acetate emulsions, where it acts as a thickener and protective colloid. 

Cellulose ethers have also been used in the ceramic industry (7). Since their appearance in 1959, water-based cellulose ethers have replaced solvent-based adhesives. The adhesives used for ceramic tile are ready-mixed products based on natural or synthetic rubber, polyvinyl acetate, and other resins, and they all contain cellulose ethers of one kind or another (e.g. MC, EC, HPMC, HEMC, HEC). These cellulose ethers reduce water loss, modify the viscosity of the mix, and can provide excellent adhesion for dry, very porous tiles. 

Cellulose Ethers and Polymerisates cellulose and emulsion powders for coatings, mortars, building materials, insulation, adhesives, and tin for the pharmaceutical and food industries. Polyvinyl alcohol/butyral for adhesives, paper, textile processing, inks, paints and laminated glass. 

The two major commercial organosoluble cellulose ethers, ethyl-cellulose and ethyl(hydroxyethyl)cellulose (EHEC), are filmforming polymers distinguished by unusual properties and versatility (22). They contribute to the basic film properties of special types of inks, coatings, and adhesives. Their special utility results from the following performance properties (23) ... 

Dimethylacetal [534-15-6] (acetaldehyde dimethyl acetal, 1,1-dimethoxyethane) is a neutral liquid that is miscible with water and organic solvents. It dissolves cellulose nitrate, cellulose ethers, poly(vinyl acetate), polyacrylates, polymethacrylates, poly(vinyl ethers), some vinyl chloride copolymers, and synthetic and natural resins. It does not dissolve poly(vinyl chloride), polystyrene, chlorinated rubber, and cellulose acetate. It is used in the production of paints, adhesives, and shoe-cap stiffeners. 

The cellulose ethers constitute another important group of cellulose derivatives prepared from alkali cellulose by standard etherification reactions between the hydroxyl groups and an alkyl halide. The properties of the ethers depend on the extent of the reaction that is, the degree of etherification. In general, the ethyl celluloses are water-insoluble thermoplastic materials, whereas methyl ether, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose are soluble in cold water and are used as viscoelastic thickeners and adhesives. 

Cellulose derivatives have found industrial applications for over 150 years. They have been used in such a wide-ranging application adhesives, building materials, inks, and munitions. Within the health and wellness area, cellulose derivatives have a long history of use as binders, coatings, viscosity modifiers, and release modifiers. This entry will present the chemistry of cellulose ethers a key class of cellulose derivatives and the clinical benefits they bring to food and pharmaceutical products. 

Stabilizer, suspending agent in oral and topical solution or suspension Mixed alkyl hydroxyalkyl cellulosic ether Suspending, viscosity-increasing and film-forming agent Tablet binder and adhesive ointment ingredient... 

Uses Solvent for cellulose ethers, fats, oils, waxes, inks, lacquers, resins, coatings paint and varnish remover extraction solvent for essential oils glass substitutes laboratory reagent chemical intermediate in fungicidal formulations mfg. of nylon, adipic acid, benzene, cyclohexanone, etc. mfg. of solid fuel for camp stoves diluent in food colorants solvent in cosmetics, pharmaceutical orals in food-pkg. adhesives defoamer in food-contact paper coatings... 

Uses Extraction solvent foundry resins perfume fixative solvent for coatings, lacquers, cellulose esters, cellulose ethers, oils, resins mfg. of printing inks, lacquers nondiscoloring plasticizer for cellulosics, PVAc in food-pkg. adhesives Regulatory FDA 21CFR 175.105 Manuf./Disthb. A.P. Chems. Ltd Aceto http //www.aceto.com, Aldrich http //www.sigma-aldrich.com, Ashland http //www.ashchem.com, BP Amoco http //www.bpamoco.com. 

Synonyms 2,3-Dihydroxypropanal Glyceric aldehyde Glycerose Empirical CsHeOs Formula HOCH2CH2OCHO Properties Tasteless cryst. insol. in benzene, petroleum ether, pentane m.w. 90.09 m.p. 145 C Toxicology LDLo (oral, rat) 5 g/kg Uses Biochemical research intermediate nutrition preparation of polyesters adhesives cellulose modifier leather tanning... 

Cellulose and its derivatives have been and are commercially and scientifically important. They are used in the production of paper textiles and fibers (e g., rayon) films (e.g., cellophane) gums and thickeners (e.g., cellulose ethers) foods pharmaceuticals cosmetics explosives and propellants (e.g., nitrocellulose) and adhesives. In addition, the hydrolysis of cellulose is actively being studied as raw material for the production of alcohol fuels (6) and chemicals (7). As nonrenewable materials are depleted, the importance of cellulose as a chemical raw material will increase. Analysis and characterization of any... 

These include ethyl cellulose, hydroxy ethyl cellulose, methyl cellulose, sodium carboxy methyl cellulose, and benzyl cellulose. Ethyl and benzyl cellulose can be used as hot-melt adhesives. Methyl cellulose is a tough material, completely non-toxic, tasteless, and odorless, which makes it a suitable adhesive for food packages. It is capable of forming high-viscosity solutions at very low concentrations, so it is useful as a thickening agent in water-soluble adhesives. Hydroxy ethyl cellulose and sodium carboxy methyl cellulose can also be used as thickeners. The cellulose ethers have fair to good resistance to dry heat. Water resistance varies from excellent for benzyl cellulose to poor for methyl cellulose. ... 

Cellulosic membranes are developed as a novel dmg delivery system, which is expressed to use on the skin and used as a mucus membrane of stomach, ear, nose, eye, rectum, and vagina. The goal excipients of these preparations are adhesive and film-former polymers. Modified cellulose, especially cellulose ethers, are extensively applied in bio-adhesives such as nasal, vaginal, ocular, buccal, and transdermal inventions only or by blend with additional polymers. Further newly applied ethers of cellulose in bio-adhesives contain anionic ether derivatives such as sodium carboxy-methyl cellulose (NaCMC) and non-ionic cellulose ethers such as hydoxypropyl cellulose (HPC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose, ethyl cellulose (EC), hydroxylpropylmethyl cellulose (HPMC), or methyl cellulose (MC). Capability of polymer to absorb water from mucus and pH of objective area are main features defining the adhesive power of polymers. One benefit of cellulose ethers, such as HPC and NaCMC, is smaller dependence of adhesion period and their adhesion strength to pH of medium than thiolated bio-adhesive polymers and polyacrylate... 

Grabovac et al., 2005). Only bio-adhesives of cellulose ethers, or its mixtures with additional polymers, have been studied in oral (Deshpande et al., 2009 Venkatesan et al., 2006), buccal (Perioli et al., 2004), ocular (Ludwig, 2005), vaginal (Karasulu et al., 2004), and transdermal (Sensoy et al., 2009). 

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