Urea-formaldehyde foams applications

Prefabricated polystyrene foam sheets are used mainly for thermal insulation and waterproofing in basements. Polyethylene foam is used, e.g. for pipe insulation, and is fixed with an adhesive or tape. Urea-formaldehyde foam was used for improving thermal insulation in old houses, but uncontrollable formaldehyde emissions have caused its use to be minimised. Polyurethane foam is used for thermal insulation as prefabricated foam forms, e.g. on pipes and as sheets on roofs or walls. In pipe insulation, adhesives may be used in fixing. Uncured diphenylmethane diisocyanate-based (MDI) polyurethane foam is sprayed on site (e.g. for window frames) or for technical applications (e.g. on large boilers). When spraying foam on boilers, good ventilation and personal protection is needed. Tools used in thermal insulation include knives, saws, scissors, jointing tools, etc. 

Materials from starch crosslinked with melamine-formaldehyde, methylated melamine-formaldehyde, and other amine-aldehyde resins were patented as binders for filter paper,1336 milk filter sheet materials,1338 and aqueous papercoating compositions containing clay, titanium(IV) oxide, butadiene-styrene latex, and calcium octadecanoate.1396,1397 Foams for filters were developed.1398 A heatsetting adhesive was one of the first applications reported for starch crosslinked by urea-formaldehyde and phenol-formaldehyde resins.1331,1340-1342,1347,1372,1399... 

Urea-formaldehyde resins are applied in the field of electronics. They possess superior electrical insulation properties compared to phenolic resins and are used in the production of mainly sockets, plugs and switches. A special application of urea-formaldehyde resins consists in the obtaining of foams for placing on airport... 

Urea-formaldehyde (UF) foams are available in densities ranging from 80-160 kg/m both as in situ foams or preshaped. They have a narrow working range of temperature 243K ( 30°C) to 320K (47°C). In addition, the foams readily absorb a variety of liquids including water. This leads to one important application—cut flower arrangements UF foam of low density is easily pierced by the stems of flowers and the foam will absorb sufficient water to keep the flowers fresh for several days. 

Fosm. Phenolic resin foam is a cured system composed of open and closed cells with an overall density of 0.16-0.80 g/cm . Principal applications are in the areas of insulation and sponge-like floral foam. The resins are aqueous resoles catalyzed by NaOH at a formaldehyde/phenol ratio of 2 1. Free phenol and formaldehyde content should be low, although urea may be used as a formaldehyde scavenger. 

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