Urea formaldehyde resin glues

The consumption in the USA in 1996 was 3.83 10 t N, of which 83% was used in fertilizers. Half of the consumption in fertilizers was utilized in liquid fertilizers e.g. in urea-ammonium nitrate. solutions, the rest being used in solid fertilizers. 7% of urea was utilized for animal nutrition and 6% for urea-formaldehyde resins, glues and melamine. In the period between 1984 and 1996 there was a reduction in urea capacity in Western Europe of 39% to 2.5 10 t/a N (Table 2.2-7). 

In hardwood plywood, the glue mix is typically formed by adding water and soft wheat flour at rather high proportions with a minor addition of filler, such as nut shell flour to the urea-formaldehyde resin. Urea-formaldehyde resins are usually shipped in 60 - 65 percent non-volatile solids form. Acid salts such as ammonium sulfate are added to increase the rate of cure of the urea-formaldehyde resin when under pressure and subsequently heated in hot presses. Some acid salts cure the urea-formaldehyde sufficiently well under ambient "cold" press conditions. It is evident this type of plywood would be oriented toward interior use such as furniture. If water-proof type bonds are required of hardwood plywood, then melamine-formaldehyde resins are used in similar mix form but with higher resin solids... 

Results of a 2-year paint study indicate acetylated wood is a better painting surface (37) than untreated wood. UV radiation darkens unacetylated wood, but there is no change or a slight bleached effect with acetylated wood (37). In general, acetylation reduces the adhesive strength of wood (48). Adhesive strength is reduced with urea-formaldehyde resins (54, 55) and casein glues (55), but there is very little effect with resorcinol-formaldehyde resins (55). 

Urea-formaldehyde resins as binding agents in thermal insulation and textile treatment, as glue in chip board, wood floorings, and lacquers >60-70 Degradation, formaldehyde... 

Chemical reactions in sources are well known from hydrolysis of urea formaldehyde resins in chipboard resulting in the emission of formaldehyde and from the hardening processes of many sealants, glues, and varnishes (Roffael, 1993). The emission of volatile compounds from these products may in some cases be limited by formation. 

Uses Mfg. of phenolic and thermosetting resins, furan polymers, urea-formaldehyde resins wetting agent foundry sand binders corrosion-resist, resins intermediate for esterification and etherification paints solvent, plasticizer for phenolic resins solvent for dyes and resins nonreactive epoxy resin diluent vise, reducer, cure promoter, and carrier in amine-cured epoxy resins gel retarder in casein/protein glues polymer sealants/cements synthetic flavoring agent in foods and pharmaceuticals cosmetics ingred. in food-pkg. adhesives... 

Butadiene/acrylonitrile copolymer adhesive, food-packaging food containers D-Mannitol adhesive, furniture Urea-formaldehyde resin adhesive, glass Epoxy resin Polyvinyl acetate adhesive, glass fibers Styrene/PVP copolymer adhesive, grinding disks Animal glue adhesive, hair care Polyquaternlum-14 adhesive, heat-resistance Silicone elastomer... 

The adhesives developed for the manufacture of damp-ply-resistant corrugated cardboard are based on the addition of spray-dried wattle extract, urea-formaldehyde resin, and formaldehyde to a typical Stein-Hall starch formula with 18-22 per cent starch content [75, 76]. The wattle tannin-urea-formaldehyde copolymer formed in situ and any free formaldehyde left in the glue line are absorbed by the wattle tannin extract. The wattle extract powder should be added at level of 4—5 per cent of the total starch content of the mix (i.e. carrier plus slurry). Successful results can be achieved in the range of 2-12 per cent of the total starch content, but 4 per cent is the recommended starting level. The final level is determined by the degree of water hardness and desired bond quality. This wattle extract UF-fortifier system is highly flexible and can be adapted to damp-proof a multitude of basic starch formulations. 

Kaurit glue Urea-formaldehyde resin BASF, Germany... 

Urea-formaldehyde resin and melamine-formalde-hyde resin are used as glues in the wood industries to make furniture press plates. Despite a low constant release of formaldehyde from these plates into the indoor air, the health effect for individuals living or working in the room is way overestimated in our opinion. Construction workers are also exposed to formaldehyde resins in modern building materials. Textile finishes are another use for these formaldehyde resins, but this does not fit into our discussion in this chapter (Fowler et al. 1992). Even cosmetics may contain PTBP-FR as Angelini and others have shown previously (Angelini et al. 1993). Both resins are currently available from Chemotechnique, Sweden, urea-FR as a 10% petrolatum and melamine-FR as a 7% preparation in the textile colour and finishes series. 

Phthalic anhydride, 1% (polyester resin component) Resorcinol, 2% petrolatum (adhesives and glues) Styrene, 1% (polyester resin cross-linker) Toluenediisocyanate, 2% petrolatum Turpentine, 1% olive oil (furniture polishes) Urea-formaldehyde resin, 10% petrolatum (fibre board glue)... 

Tricresyl phosphate, 2% pet (plasticizer in adhesives) Triethylenetetramine, 0.5% pet (epoxy catalyst) Turpentine, 10% olive oil (furniture polishes) Urea-formaldehyde resin, 10% pet (fiberboard glue) Various wood dusts, 10% pet... 

Mixed Glues. Starches and dextrins also are used in combination with other raw materials in adhesives. For example, the resistance to water of starch-based adhesives can be improved by the addition of melamine-formaldehyde or urea-formaldehyde resins. Mixtures of starch-based adhesives or dextrin-based adhesives with synthetic resin dispersions are also used. 

Kauri Glue Urea-formaldehyde resin, manufactured by BASF, Germany. 

In order to take advantage of the new abrasive grit materials, new and improved bond systems had to be developed. Subsequently, adhesive systems have also come a long way, progressing from fish and animal hide glues to urea-formaldehyde resins, epoxies, phenolic, and radiation-curable systems. This evolution has placed a continuing demand on the adhesive systems used in the manufacturing of abrasive products. 

Dunky, M., Urea-formaldehyde glue resins. In Salamone, J.C. (Ed.), Polymeric Materials Encyclopedia, Vol. 11. CRC Press, Boca Raton, FL, 1996. 

Uses of Formaldehyde. Formaldehyde is the simplest and most reactive aldehyde. Condensation polymerization of formaldehyde with phenol, urea, or melamine produces phenol-formaldehyde, urea formaldehyde, and melamine formaldehyde resins, respectively. These are important glues used in producing particle hoard and plywood. 

Figure 9 depicts the somewhat similar behavior for a room-temperaturesetting, urea-formaldehyde or phenol-resorcinol-formaldehyde resin-based glue. However, no initial heat-related drop in viscosity occurs during clamping, and the final polymerization hardening proceeds at a slower rate because it occurs at room temperature. 

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