Urea-formaldehyde resins, coatings

Syntactic Cellular Polymers. Syntactic cellular polymer is produced by dispersing rigid, foamed, microscopic particles in a fluid polymer and then stabilizing the system. The particles are generally spheres or microhalloons of phenoHc resin, urea—formaldehyde resin, glass, or siUca, ranging 30—120 lm dia. Commercial microhalloons have densities of approximately 144 kg/m (9 lbs/fT). The fluid polymers used are the usual coating resins, eg, epoxy resin, polyesters, and urea—formaldehyde resin. 

Urea—formaldehyde resins are also used as mol ding compounds and as wet strength additives for paper products. Melamine—formaldehyde resins find use in decorative laminates, thermoset surface coatings, and mol ding compounds such as dinnerware. 

Other amino resins besides MF resins are used to a lesser degree in coatings. Urea—formaldehyde resins are used in some coatings for wood furniture because these resins cross-link at lower temperatures than MF resins and the higher water resistance and exterior durabiUty that can be obtained using MF resins are not needed. Ethers of formaldehyde derivatives of 6-phenyl-l,3,5-triazine-2,4-diamine [91-76-9] (benzoguanamine resins) give... 

Many alternatives to nitrocellulose lacquers for top coats have been investigated and some are used commercially. Especially for lower cost furniture exposed to hard use such as motel and institutional furniture, alkyd—urea top coats are used. Urea—formaldehyde resins, in contrast to... 

Modified melamine resins are also employed commercially. Alkylated resins analogous to the alkylated urea-formaldehyde resins provide superior coatings but are more expensive than the urea-based products. 

Uses The urea formaldehyde resins are used for domestic electrical fittings, bottle caps. These also find use for wood adhesives, surface coatings and textile finishings. 

Urea-formaldehyde resins F iberglass-reinforced polyurethane F iberglass-reinforced polyurethane Polyurethanes Rigid polyurethanes Polyurethane elastomeric coatings... 

Another use of urea is for resins, which are used in numerous applications including plastics, adhesives, moldings, laminates, plywood, particleboard, textiles, and coatings. Resins are organic liquid substances exuded from plants that harden on exposure to air. The term now includes numerous synthetically produced resins. Urea resins are thermosetting, which means they harden when heated, often with the aid of a catalyst. The polymerization of urea and formaldehyde produces urea-formaldehyde resins, which is the second most abundant use of urea. Urea is dehydrated to melamine, which, when combined with formaldehyde, produces melamine-formaldehyde resins (Figure 96.2). Melamine resins tend to be harder and more heat-resistant than urea-formaldehyde resins. Melamine received widespread attention as the primary pet food and animal feed contaminant causing numerous cat and dog deaths in early... 

Oligophenylethoxysiloxanes are used as modifiers for various polymers to improve their weather resistance and other technical characteristics, as well as to increase the heat resistance of coatings. E.g., PES-50 is used to modify polyethers, aciylic and epoxy polymers PES-80 is used to modify alkyd and urea-formaldehyde resins. Besides, PES-80 is used as an additive in paints and enamels (to improve their flow properties, gloss and colour), as well as in concrete mixes (to improve the water resistance and durability of concrete works). 

Immerse for 5-10 min at 90°C in potassium permanganate (saturated solution), acidified with sulfuric acid (96%). Rinse in water and distilled water. Dry in warm air. 4. Prime surface with a lacquer based on urea formaldehyde resin diluted with carbon tetrachloride. Coatings (dried) offer excellent bonding surfaces without further treatment... 

Molded articles from cellular polysulfone, coated with polystyrene, epoxy resin, or vinyl resin, are reported to have improved hardness and surface rigidity. They can also be used as insulating or packaging materials, or, when modified with urea-formaldehyde resin, as flowerpots that are permeable to air and water. These foams have excellent selfextinguishing and low anoke-generating properties (21). 

Unmodified urea-formaldehyde resins are unsuitable for use in surface coatings formulations, due to their lack of solubility in common solvents and incompatibility with other resins. This limitation can be substantially overcome when the resins are modified by alcohols, such as n-butanol. Very commonly, butylated urea-formaldehyde resins are blended with alkyd resins to provide good flexibility and adhesion in coatings. Furfuryl alcohol-modified urea resins are used to bind foundry cores formed in preheated pattern boxes, due to their capability of rapid core production. 

Cellulose acetate is compatible with cellulose nitrate, but little benefit has resulted from using the two together in a coating composition. Limited use has been made of cellulose acetate in reactive compositions even though it is compatible with urea-formaldehyde resins. 

Hercules Resin 917. [Hercules] Cationic urea-formaldehyde resin aq. sol n. thermoset for modifying water-sol. polymers, inq>arting water resistance to films, coatings. 

PlastopakB. [BASF AG] Urea-formaldehyde resins, butanol or methanol etherified binders fca baking finishes, acid-curable coatings, film coatings, ni-trocdlulose finishes, epoxy finisl. ... 

Chem. Descrip. Methylated urea-formaldehyde resin in isopropyl alcohol Uses Crosslinking agent for water-disp. polymers containing hydroxyl or amide tunctionalities on low bake schedules, yielding tough, tack-free coatings... 

Uses Catalyst for accelerating cure of fully alkylated melamine-formaldehyde, benzoguanamine, glycoluril, and urea-formaldehyde resins, for air atomized spray applies., dipping enamels, water redudble systems, wood finishes, paper coatings... 

Chem. Descrip. Butylated urea-formaldehyde resin in n-butanol solv. Uses Crosslinking agent for wood and metal coatings Features Exc. compat. with other resins provides good durability, hydrolytic stability, film flexibility 0.5% max. free formaldehyde Properties APHA 30 max. color dens. 8.75-8.95 Ib/gal vise. (Gardner-Holdt) X-Z3 flash pt. (PMCC) 85 C 94-98% solids Resin 1265-M-70 [Ranbar Tech.]... 

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