Solubility, wood

The use of gypsum binders with improved water resistance is indicated in applications in which limited exposure of the hardened material to liquid water is to be expected. As the setting and hardening of the binder are not impeded by soluble wood constituents, binders of this kind are also suitable for use in the production of particle boards (Deng et al., 1998). 

Aluminum primers are used on resinous timber or timber, which has been treated with oil-soluble wood preservatives. 

Lundqvist, J. Isolation, characterization and enzymatic hydrolysis of water-soluble wood polysaccharides. Ph.D. Thesis 2002, Lund university, Lund... 

Aluminum Primer n (1) Primer specifically formulated for aluminum metal. (2) Primer containing a proportion of aluminum pigment, but distinguished from aluminum paints in which the aluminum is designed to float to the top of the film giving metallic brilliance, a feature undesirable in a primer. Aluminum primers are used on resinous timber or timber which has been treated with oil-soluble wood preservatives. 

C (rapid heating). Manufactured by the oxidation of lactose or the galactans from wood with nitric acid. When heated with water it forms a soluble lactone. Converted to furoic... 

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). 

Arabinan. This highly soluble polymer is found in the extracts of many fmits and seeds, in the boiling water extracts of pine wood (127), in the extracts of marshmallow roots (A/t/jaea officina/is) (128), and aspen (63) and willow (Sa/ix a/ba F) (129) bark. Because arabinan can be isolated from mildly degraded pectin fractions, it is often difficult to determine whether it is a hemiceUulose or a labile fragment of a larger polysaccharide and/or lignin complex. Arabinans have a complex stmcture composed almost entirely of 5-linked a-L-arabinofuranosyl units with similar residues linked to them at C-2 and/or C-3 and is soluble in 70% aqueous methanol solution. 

Table 13 shows some of the developmental products that have EPA appHcations pending and may be available in the near future. Sea Nine is a variation on the very successflil isothiazolone chemistry. It is claimed to be an improvement over metallic actives used for antifouling paint and wood preservation (46,47). Decylthioethylamine and its water-soluble hydrochloride are claimed to be especially effective at controlling biofilm in cooling water appHcations (48—50). The hydroxymethylpyra2ole shown is also suggested to have properties that are well suited to the protection of aqueous products or emulsions (51,52). 

The significance of phenoxy anions is well recognized in the isolation of kraft and other water-insoluble technical lignins by acid precipitation. The ioniza tion of phenoHc hydroxyl groups coupled with the reduction of molecular size renders native lignin soluble in the aqueous pulping solution, thus enabling its separation from the polysaccharide components of wood. 

Sulfonamide groups can be introduced into phthalocyanines to make them soluble in alcohols and glycol ethers. Their main appHcations are transparent paints, flexo and gravure printing inks, wood stains, plastics, and ballpoint inks. This includes products Hke Solvent Blue 24 (Cl 74380),... 

BenZenetetrol. 1,2,3,4-Tetiahydioxybenzene 01 apionol (59) forms needles from benzene (mp 161°C). It is easily soluble in water, diethyl ether, ethanol, and glacial acetic acid and is spariagly soluble ia benzene. It has been identified as one of the many constituents of wood—vinegar distillate (202). 

Tall oil rosin is a by-product of paper manufacturing. Raw wood chips are digested under heat and pressure with a mixture of sodium hydroxide and sodium sulfide. Soluble sodium salts of lignin, rosin, and fatty acids are formed, which are removed from the wood pulp as a dark solution. The soaps of the rosin and fatty acids float to the top of the mixture, where they are skimmed off and treated with sulfuric acid to free the rosin and fatty acids. This mixture, known as cmde tall oil (CTO), is refined further to remove color and odor bodies fractional distillation separates the tall oil rosin acids from the fatty acids (see Tall oil). 

Sandarac. This resin, which originates in Morocco, is a polar, acidic, hard resin with a softening point of 100—130°C, an acid number of 117—155, and a saponification number of 145—157. Sandarac [9000-57-1] is soluble in alcohols and insoluble in aryl and aUphatic hydrocarbons. It is used in varnishes and lacquers for coating paper, wood, and metal. 

Mastic. Most commercial mastic [61789-92-2] is collected on the Greek island of Chios, near the Turkish coast. It is a soft resin with a softening point of 55°C. It has an acid number of 50—70 and a saponification number of 62—90. It is soluble in alcohols and aryl hydrocarbons. Mastic is used in wood coatings, lacquers, adhesives, and printing inks. 

In the case of low temperature tar, the aqueous Hquor that accompanies the cmde tar contains between 1 and 1.5% by weight of soluble tar acids, eg, phenol, cresols, and dihydroxybenzenes. Both for the sake of economics and effluent purification, it is necessary to recover these, usually by the Lurgi Phenosolvan process based on the selective extraction of the tar acids with butyl or isobutyl acetate. The recovered phenols are separated by fractional distillation into monohydroxybenzenes, mainly phenol and cresols, and dihydroxybenzenes, mainly (9-dihydroxybenzene (catechol), methyl (9-dihydtoxybenzene, (methyl catechol), and y -dihydroxybenzene (resorcinol). The monohydric phenol fraction is added to the cmde tar acids extracted from the tar for further refining, whereas the dihydric phenol fraction is incorporated in wood-preservation creosote or sold to adhesive manufacturers. Naphthalene Oils. Naphthalene is the principal component of coke-oven tats and the only component that can be concentrated to a reasonably high content on primary distillation. Naphthalene oils from coke-oven tars distilled in a modem pipe stiU generally contain 60—65% of naphthalene. They are further upgraded by a number of methods. 

Water-borne adhesives are preferred because of restrictions on the use of solvents. Low viscosity prepolymers are emulsified in water, followed by chain extension with water-soluble glycols or diamines. As cross-linker PMDI can be used, which has a shelf life of 5 to 6 h in water. Water-borne polyurethane coatings are used for vacuum forming of PVC sheeting to ABS shells in automotive interior door panels, for the lamination of ABS/PVC film to treated polypropylene foam for use in automotive instmment panels, as metal primers for steering wheels, in flexible packaging lamination, as shoe sole adhesive, and as tie coats for polyurethane-coated fabrics. PMDI is also used as a binder for reconstituted wood products and as a foundry core binder. 

Wood ash generally contains calcium, potassium, phosphoms, magnesium, and siUca. Ashes recovered from burned wood are - 25% water soluble and the extract is strongly alkaline. The ash fusion temperature is in the range of 1300 to 1500°C. 

Amino Resins. Amino resins (qv) include both urea- and melamine—formaldehyde condensation products. They are thermosets prepared similarly by the reaction of the amino groups in urea [57-13-6] or melamine [108-78-1] with formaldehyde to form the corresponding methylol derivatives, which are soluble in water or ethanol. To form plywood, particle board, and other wood products for adhesive or bonding purposes, a Hquid resin is mixed with some acid catalyst and sprayed on the boards or granules, then cured and cross-linked under heat and pressure. 

Cellulose acetate butyrates with high butyryl content and low viscosity are soluble in inexpensive lacquer solvents. They are widely used in lacquers for protective and decorative coatings appHed to automobiles and wood furniture. 

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