Urea-formaldehyde foam

Sources of human exposure to formaldehyde are engine exhaust, tobacco smoke, natural gas, fossil fuels, waste incineration, and oil refineries (129). It is found as a natural component in fmits, vegetables, meats, and fish and is a normal body metaboHte (130,131). FaciUties that manufacture or consume formaldehyde must control workers exposure in accordance with the following workplace exposure limits in ppm action level, 0.5 TWA, 0.75 STEL, 2 (132). In other environments such as residences, offices, and schools, levels may reach 0.1 ppm HCHO due to use of particle board and urea—formaldehyde foam insulation in constmction. 

Formaldehyde from particle board, pressed wood, urea-formaldehyde foam insulation, plywood resins, hardwood paneling, carpeting, upholstery ... 

Debate is continuing on the safety and toxicity of formaldehyde and its products, especially urea-formaldehyde foam used as insulation in construction and phenol-formaldehyde as a plywood adhesive. Presently the TLV-STEL of formaldehyde is 0.3 ppm. Formaldehyde is on the Reasonably Anticipated to Be Human Carcinogens list. 

By a modification of the method described in Sect. 4.1.3 urea/formaldehyde foams can be prepared with the following method ... 

This property can be used to separate highly volatile and low-viscous mineral oils from oil-water dispersions.To demonstrate this,a dispersion of 20 ml of ligroin or petroleum ether in 200 ml of water is prepared in a 400 ml beaker with a fast-running mixer.Then approx. 5 g of crushed urea/formaldehyde foam are added. After 5 min the solution is filtered through a folded filter.The aqueous filtrates are optically free from dispersed hydrocarbons. In the same way a crude oil/water dispersion can be separated. 

The fate of the urea formaldehyde foam industry is a classic example of the power of public reaction. Urea formaldehyde foam insulation which was not installed properly emitted formaldehyde fumes which caused discomfort and, in some cases, allergic reactions. Formaldehyde also was identified as a suspect carcinogen. The product became unmarketable long... 

Formaldehyde is an important industrial chemical for the production of synthetic resins. These resins are applied primarily as adhesives in the production of a large number of consumer products and construction materials that end up in homes. Other sources of indoor formaldehyde include urea-formaldehyde foam insulation, textile additives, as well as combustion and tobacco smoke. Formaldehyde is one of the many VOCs present indoors and it is considered the most abundant among them. It has important toxic effects in the 0.1-5 ppm concentration range. 

OFM oligoester fumarate maleates UF foam urea-formaldehyde foam... 

Baumann, H, Preparation and Processing of Urea-Formaldehyde Foam Polymers. Jap. 

Polyisocyanurate foams, polyurea foams and phenolic foams are growing rapidly in recent years. Urea-formaldehyde foams disappeared recently from the U.S. market. Rubber foams and pyranyl foams are no longer available in the worldwide market. 

In this section isocyanate-based polyurea foams ja-oduced by the reaction of the water-isocyanate or amine-isocyanate reactions will be described. Urea-formaldehyde foams will be excluded. The isocyanate-based urea-linkage formation is shown by the following model reactions ... 

MISCELLANEOUS AND SPECIALTY FOAMS (Epoxy Foams, Polyester Foams, Silicone Foams, Urea-Formaldehyde Foams, Polybenzimidazole, Foams, Polyimide Foams, Polyphosphazene Foams, and Syntactic Foams)... 

Urea-formaldehyde foams are usually brittle structures with low compressive strength (under 50 psi or 0.34 MPa). The term "frangible" may be applied to them. They are open-cell, sponge-like foams that can absorb large quantities of water. Hiese foams also exhibit thermal and acoustical insulating properties common to low-density foams. For example, their thermal conductivities range within the values quoted for polystyrene foam (0.24 - 0.33). This is the result of their low density and snail cell size (5). 

Staff written, "The Screws Are Off Urea Formaldehyde Foam," Industry and Market News, Modern Plastics, 60 (6) 136, 138 (June 1983). 

Urea-formaldehyde Foams. While urea-formaldehyde (UF) foams can be rated as difficult to bum, blending of UF with another polymer can decrease the resistance of the foam to burning. Fire retardants, including phosphorus and boron compounds, have been added to decrease the flammability of UF foams (42). According to Frisch (42) phosphonates, furfuryl alcohol and ethylene glycol have been used as fire retardants. 

Frisch, K.C., "Urea-Formaldehyde Foams," Chapter 12 in Plastic Foams, Part II, K.C. Frisch and J.H. Saunders, Editors, Marcel Dekker, Inc., New York (1973). 

Broder I, Corey P, Cole P, et al. 1988a. Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. II. Initial health and house variables and exposure-response relationships. Environ Res 45 156-178. 

Day JH, Lees REM, Clark RH, et al. 1984. Respiratory response to formaldehyde and off-gas of urea formaldehyde foam insulation. Can Med Assoc J 131 1061-1065. 

Godish T, Fell J, Lincoln P. 1984. Formaldehyde levels in New Hampshire urea - formaldehyde foam insulated houses. Relationship to outdoor temperature. J Air Pollut Control Assoc 34 1051-1052. 

Pross HF, Day JH, Clark RH, et al. 1987. Immunological studies of subjects with asthma exposed to formaldehyde and urea-formaldehyde foam insulation (UFFI) off products. J Allergy Clin Immunol 79 797-810. 

The incidences of perceptible formaldehyde in schools, homes, and offices can cause uncertainty among building users about the safety of living with formaldehyde. This uncertainty has led to the closing of schools in Germany, Switzerland and Eastern countries. In North America it was enhanced by the large scale installation of urea formaldehyde foam insulation (IIFFI), because a substantial part of this material was made from small scale resin batches prepared under questionable quality control conditions and was installed by unskilled operators (32), often in unsuitable locations. 

Formaldehyde (CH2O) release was measured for seven types of consumer products pressed wood, urea formaldehyde foam materials, clothes, insulation, paper, fabric, and carpet. A modified Japanese Industrial Standard (JIS) desiccator test was used to measure release rate coefficients and to rank 53 products. Ten pressed wood products and five urea formaldehyde foam products showed the highest CH2O releases (1-34 mg m 2.day"b The remainder, representing all product types, had lower releases ranging from 680 yg m 2.day to nondetectable levels. In other studies, CH2O release was measured in a ventilated chamber for single samples of particle board, plywood, insulation, and carpet. 

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