Cavity-wall insulation

High-temperature work, fire protection, acoustics, sprayed fiber, molded products, cavity-wall insulation, loft insulation. 

Polyurethane foams are widely used. Rigid foams, for example, are used in cavity wall insulation in buildings, while flexible foams have, until recently, been used in soft furnishing for domestic use. They continue to be used in car seating. In addition to foams another major use of polyurethanes is in surface coatings. A variety of polyurethane-based polymers, some of considerable complexity, are used for this purpose, but all share the common desirable features of toughness, flexibility, and abrasion resistance. 

Foaming of urea - formaldehyde resins for cavity wall insulation Alkylbenzene sulphonic acids and salts Foaming agents... 

Warm houses, heated by efficient fuels and insulated by double glazing and cavity wall insulation. . . thank the chemists for processing the natural gas and oils, and also for synthesising the polymers and plastics that make the window frames and foam cavity wall insulation. 

Foams are available as rigid sheets or slabs (which are used in the majority of roofing systems), as beads and granules (used in cavity wall insulation), and also as spray and pour-in applications. The market is dominated by polyurethane (PU) foams, in particular polyisocyanurate products, expanded polystyrene (PS), and extruded polystyrene. 

Major applications Electrical fittings, telephone handsets, radio housings, cigarette boxes, lampshades, tableware, cavity wall insulation (UFFI) from 1950s until 1980 when it was discontinued due to concern over formaldehyde toxicity. 

Ammonia and methanol are starting points for amino-resins, which are therefore syngas derivatives. Urea-formaldehyde resins are used in particle board (chipboard) and plywood manufacture UF-foam is also widely used for cavity wall insulation in the U.K. Melamine-formaldehyde resins are possibly more familar from the dinnerware and heat-resistant wood finishes produced. 

Foams are used in fiuniture (upholstery, mattresses) packaging, refrigeration and insulation panels, storage and shipping tanks, shoe soles and flotation products. Considerable amounts are used in construction to make roofs and cavity wall insulation, and as a low cost substitute for... 

Urea—Formaldehyde and Urea-Based. In the 1970s and early 1980s, urea materials were in general use particularly for direct field retrofitting of cavity wall constmction of wood frame and masonry. However, because of formaldehyde odor and excess shrinkage under specific conditions, this ceUular plastic has limited use as an insulation. 

Amongst applications reported are underfloor footfall sound insulation, thermal insulation between cavity walls and pipe insulation. 

As mentioned above, insulation applied to externally located equipment can be subjected to rain and weather contamination if the outer cladding fails. Insulants with water-repellant, water-tolerant or free-draining properties offer an additional benefit in this type of application. In the structural field insulants used as cavity wall fills must be of those types specially treated and designed for this application. 

The use of this catalytic system permits foam formation to proceed without the need to supply external heat to the reaction mixture after the reactants are brought together. This permits pouring-in-place of the foam-forming system, for example, in the insulation of cavity walls for construction purposes, in trailer walls, and in cold-storage firameworks and the like. 

BS 5617 1985 Specification for Urea-Formaldehyde (UF) Foam Systems Suitable for Thermal Insulation of Cavity Walls with Masonry or Concrete Inner and Outer Leaves, 17 pp... 

Rossiter and Brown, 1990). The foamed cement was formulated as a calcium magnesium oxychloride silicate composition and was pumped into the cavity walls of the test house. The density of cement was 46.5 kg m-3 and had a measured thermal conductivity of 0.0430 W/m°C at 24°C, which is comparable to other commercially available insulation materials. 

BS 5617 [28] is a specification for urea-formaldehyde foam systems suitable for thermal insulation of cavity walls. Appendix C describes a method for water absorption using a 100 X 100 X 40 mm sample floated on the surface of the water for 24 hours. 

Cavity insulation applications, where a solid foam is produced in situ inside the cavity walls, without dismantling the walls are done hy direct injection of the liquid mixture of components and catalyst together into the cavity. This method is simple enough to carryout, but has the risks of carrying toxic chemicals and remnants of monomer with the foam structure, that can later migrate slowly indoors. 

---