Rigid foam wood composites

Brookfield, Ct., SPE, 2002, Paper 568, Session W7-Vinyl Plastics. Vinyl Composites, pp.6, CD-ROM, 012 MOISTURE AS A FOAMING AGENT IN THE MANUFACTURE OF RIGID PVC/WOOD-1LOUR COMPOSITE FOAMS Matuana L M Mengeloglu F Michigan,Technological University (SPE)... 

A major disadvantage of composites of wood with thermoplastics materials is a relatively high specific gravity compared with those of many natural wood products. A PVC-wood composite, for example, has a specific gravity of about 1.3 g/cc. The manufacture of cellular PVC-based wood composites was studied and the properties that were achieved as the foam density was reduced were examined. Overall, even with densities as low as 0.6 g/cc, the physical properties should be adequate for many wood replacement applications. The composites also exhibited the aesthetics of wood and economics that were favourable compared with those of both rigid and cellular PVC. 6 refs. 

Rigid polystyrene foam is used for the manufacture of composite sheets, for example, for containers and prefabricated building boards. The rigid foam is combined with metals, wood-based materials, asbestos, cement, and plastic sheets. Polyurethane adhesives are particularly effective in this field. 

One of the most rapidly expanding areas of PVC technology is that of rigid foam products, leading to foam core pipe, siding substrate, sheet, profile, and wood composites (plastic lumber). Comparisons between formulations for solid and foamed products are illustrative °... 

In order to prepare wood substitutes and materials with open-cell structures, the so-called water-filled oligomeric foams are used These foams are obtained by mixing the OFM-monomeric composition with water until an emulsion is formed which is hardened after the addition of an initiator and activator. As a result, a white rigid material is obtained which is a spatial network copolymer with uniformly distributed micro-inclusions of water (2—5 nm). Optimal strength is reached at 50-60% of water, although the amount of water may be as high as 90%. At optimal water concentration, the cell walls withstand cryolitic destruction till 34 K. At 7 mass % of water the apparent denaty of the material reaches 250—9(X) kg/m and it resembles natural wood in appearance and in some properties. 

This particular manufacturer created a composite panel consisting of a glass-fiber reinforced plastic outer shell backed with a rigid polyurethane foam. The product looks like a cluster of hand split wood shakes. When installed, the panels interlock and look exactly like a shake shingle roof to the casual observer. These panels have been tested and qualify as a Class A built-up roof covering. In addition, they provide a much greater resistance to the transmission of heat than wood shake shingles. The panels are fast and easy to install and quite durable. 

Applications blow molded bottles, calendered sheet, exterior trim, fence, film, foam, pipe, profile, rigid containers, siding, windows, wood-polymer composites... 

Uses Flame retardant plasticizer for plastics incl. rigid PU and polyisocyanurate foams, PVC, carpet backing, flame-laminated and rebonded flexible foam, coatings, most thermosets, adhesives, cast acrylic sheet, wood-resin composites (particle board) fire-resist, cellulose ester plasticizer in food-pkg. adhesives Regulatory FDA 21CFR 175.105... 

Tris (P-chloroethyl) phosphate plasticizer, flame retardant rigid PU foams Tris (P-chloroethyl) phosphate plasticizer, flame retardant rubber Diphenylcresyl phosphate plasticizer, flame retardant thermosets Tris (P-chloroethyl) phosphate plasticizer, flame retardant vinyl foams t-Butylphenyl diphenyl phosphate plasticizer, flame retardant vinyl nitrile foams t-Butylphenyl diphenyl phosphate plasticizer, flame retardant wood-resin composites... 

A natural polyol of alcoholysed castor oil with triethanolamine-based rigid polyurethane foam and wood flour composite was prepared and found to show a decrease in compression modulus and yield strength with an increase in wood flour content, although good interaction of wood flour with isotyanate was noticed. Tung oil polyol-based polyurethane with pine wood flour composite was also reported. ... 

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