Plastic Wood Production

Ceramics differ from some other materials (viz. metals, plastics, wood products, textiles) in a number of individual properties, but perhaps the most distinctive difference to a designer or potential user of eeramic ware is the particularity of the individual ceramic piece. Actually ceramics are not readily shaped or worked after firing, except for some simple shapes of limited sizes. Many ceramies are manufactured as standard items refractoiy bricks and shapes, crucibles, furnace tubes, insulators, thermocouple protection tube, fibre tubes etc. 

Fomialdehyde is a basic chemical budding block for the production of a wide range of chemicals finding a wide variety of end uses such as wood products, plastics, and coatings. Table 6 shows the distribution of formaldehyde production in the United States from 1966 through 1989 (115). Production percentages reported in the following discussion are for the United States. 

Amino and Phenolic Resins. The largest use of formaldehyde is in the manufacture of urea—formaldehyde, phenol—formaldehyde, and melamine—formaldehyde resins, accounting for over one-half (51%) of the total demand (115). These resins find use as adhesives for binding wood products that comprise particle board, fiber board, and plywood. Plywood is the largest market for phenol—formaldehyde resins particle board is the largest for urea—formaldehyde resins. Under certain conditions, urea—formaldehyde resins may release formaldehyde that has been alleged to create health or environmental problems (see Amino RESINS AND PLASTICS). 

Miscellaneous. The reaction products of sahcylaldehyde with certain compounds containing active methylene groups, eg, acetylacetone, are excellent uv absorbers. Films containing these compounds can be used as uv filters to protect light-sensitive foods, wood products, paper, dyes, fibers, and plastics (95). 

Lumber and wood products Sawmills, millwork plants, wooden containers, miscellaneous wood products, manufacturing Scrap wood, shavings, sawdust in some instances, metals, plastics, fibers, glues, sealers, paints, solvents... 

Phenolic-neoprene contact cements are used for structural metal-metal bonding. especially where fatigue resistance and low temperature performance are important [209]. They are also used for bonding textiles, wood, rubbers, plastics, ceramics, and glass to metal and to one another. Solvent toxicity and flammability has greatly reduced the use of contact cements in the wood products industry. Water-based contact cements persist, but generally do not perform as well as the solvent systems, thus allowing market erosion by alternative binders. 

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

Formaldehyde Germicide, pressed-wood products, urea-foimaldehyde foam insulation (UFFI), adhesives, paints, plastics, carpeting, gypsum board, ceiling tiles and panels, wood paneling. 083 2A... 

Phenolics - [BUILDINGMATERIALS-PLASTIC] (Vol 4) -m plywood [BUILDING MATERIALS - SURVEY] (Vol 4) -m reconstituted wood products (BUILDING MATERIALS - SURVEY] (Vol 4) - [COLORANTS FOR PLASTICS] (Vol 6) -electroless plating of [ELECTROLESS PLATING] (Vol 9) -m laminates [LAMINATED MATERIALS, PLASTiq (Vol 14)... 

There are also reports of the production of boards and moldings from plasticized wood particles, pulp or sawdust without adhesives (5,8,59,60). By compressing and heating to high temperatures, particle boards can be produced which have mechanical properties comparable to conventional resin bonded boards. However, their specific gravity is on the average about twice that of ordinary commercial products (59). 

Davidson, R. W., "Plasticizing Wood with Anhydrous Ammonia," Technical Bulletin, Dept. Wood Products Engineering, SUNY College of Environmental Science and Forestry, Syracuse,... 

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