Urea-formaldehyde foam production

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. 

As measured by the modified JIS desiccator procedure, pressed wood products had the highest release rate coefficients expressed as a function of surface area (Table IIA) of the various sample types tested. Release rate coefficients from urea formaldehyde foam products were comparable to those of pressed wood products (Table IIB). Products labelled substrate (sub 1, sub 2, and sub 6) were experimental foams. The drywall that had been placed next to the foams (Number 1, 2, or 3) for more than 1 week in a configuration similar to that in a building released a moderate amount of formaldehyde. 

Pressed wood products and urea formaldehyde foam products had much higher release rates than those from most of the other products tested. Similar release rates have been observed by others (19). More than half of the products tested had very low release rate coefficients, and this included individual samples from six of seven of the types of products. Products equilibrated at 100% RH prior to the measurement were used to measure formaldehyde release. This equilibration may have removed a variable amount of formaldehyde (8, 14-17). 

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. 

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. 

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. 

Desiccator Measurements. Fifty-three different brands or lots of consumer products of seven different general types were analyzed in this study (Table I). All but two of the wood products, and the samples of urea formaldehyde foam, were purchased from commercial sources by the Consumer Product Safety Commission. The two wood products were purchased locally and are so identified. Samples of urea formaldehyde foam (UFF) were provided by Drs. 

Keith Long and Clyde Frank of the University of Iowa (Iowa City, lA). At this time Drs. Long and Frank also provided samples of drywall which had been placed next to urea formaldehyde foam for more than 1 week in a configuration like that of a building. This drywall was analyzed to determine the degree to which it had absorbed formaldehyde from the UFF and subsequently released formaldehyde under our test conditions. The time of manufacture of the products relative to acquisition was not known. After acquisition, samples were encased in plastic wrap until conditioning to minimize release of formaldehyde prior to testing (3 to 9 mo. after acquisition). 

Unwashed new clothing samples (Table IIC), fiberglass insulation products with formaldehyde resins (Table IID), paper products (Table HE), fabrics (cotton, nylon, olefin, and blended) (Table HF), and carpets (Table HG), had substantially 3 to > 100 fold) lower formaldehyde release rate coefficients, as measured by this method, than did pressed wood products or urea formaldehyde foams (1, 15). 

Urea Formaldehyde Foam Insulation Products Urea formaldehyde foam... 

Most products tested released only small amounts of formaldehyde. Only some pressed wood and urea formaldehyde foam insulation products released higher amounts of formaldehyde. Products tested in both ventilated chambers and unventilated desiccators released similar amounts of formaldehyde. Formaldehyde released by particle board was reabsorbed by the second product tested in a dynamic chamber. In a house this reabsorption might lower the room level of formaldehyde. 

During the past decade, urea formaldehyde and phenol formaldehyde resin binders have contributed greatly to the progress of wood industries. Formaldehyde is widely used as a major component in the production of building materials, such as particleboard and plywood, and in urea formaldehyde foam insulation. However, the emissions of formaldehyde from these products create considerable concerns not only in the working environments but also in residences, mobile homes, and office buildings. These concerns have also been stimulated by reports on the health effects and carcinogenicity associated with formaldehyde exposure. 

Formaldehyde is also released from aminoplasts and their derivatives, such as urea-formaldehyde foam insulation (UFFI), wood adhesives, and textile finishing agents. It is this supplemental, industrial source of formaldehyde that has become the subject of risk analysis. Should we allow products that serve our daily comfort to alter our environment by releasing an irritating vapor with a pungent odor ... 

The incidence of perceptible formaldehyde in homes, offices and schools has caused widespread uncertainty about the safety of living with formaldehyde. This uncertainty was enhanced by the large scale installation of urea formaldehyde foam insulation (UFFI) 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 (10). The only reliable way to avoid such uncertainty is to know the emission rate of products and develop a design standard that allows prediction of indoor air levels. The first and most important step in this direction was achieved with the development and implementation of material emission standards. As indicated above, Japan led the field in 1974 with the introduction of the 24-hr desiccator test (6), FESYP followed with the formulation of the perforator test, the gas analysis method, and later with the introduction of air chambers (5). In the U.S. the FTM-1 (32) production test and the FTM-2 air chamber test (33) have made possible the implementation of a HUD standard for mobile homes (8) that is already implemented in some 90% of the UF wood production (35), regardless of product use. 

Ban of Urea-Formaldehyde Foam Insulation," U.S. Consumer Product Safety Commission, Federal Register, 1982, 47, 14366-14421. 

On further addition of urea and HCHO, H(NHCO—NH—CH2) —OH is formed. With an acid catalyst, it is possible to produce a foam product known as urea formaldehyde foam insulation (UFFI) having a thermal conductivity, K, of about 0.022 Wm K . ... 

Consumer Product Safety Commission. Alert Sheet Urea Formaldehyde Foam Insulation. Washington, D.C. U.S. Government Printing Office, 1980. 

Ammonia is used in the fibers and plastic industry as the source of nitrogen for the production of caprolactam, the monomer for nylon 6. Oxidation of propylene with ammonia gives acrylonitrile (qv), used for the manufacture of acryHc fibers, resins, and elastomers. Hexamethylenetetramine (HMTA), produced from ammonia and formaldehyde, is used in the manufacture of phenoHc thermosetting resins (see Phenolic resins). Toluene 2,4-cHisocyanate (TDI), employed in the production of polyurethane foam, indirectly consumes ammonia because nitric acid is a raw material in the TDI manufacturing process (see Amines Isocyanates). Urea, which is produced from ammonia, is used in the manufacture of urea—formaldehyde synthetic resins (see Amino resins). Melamine is produced by polymerization of dicyanodiamine and high pressure, high temperature pyrolysis of urea, both in the presence of ammonia (see Cyanamides). 

Formaldehyde Germicide, pressed-wood products, urea-foimaldehyde foam insulation (UFFI), adhesives, paints, plastics, carpeting, gypsum board, ceiling tiles and panels, wood paneling. 083 2A... 

The plastic foam of 0.2mm dispersiry was homogenized with the expl components pre-ground in an edge runner. Thus, a mixt of 78.5% AN, 14.5 TNT, 5 urea-formaldehyde plastic foam, and 2% PETN was homogenized to have product of d 0.7 ]... 

The physicochemical features of the processes of formation, stabilisation and solidification of foams are best studied for a polymer foam from urea-formaldehyde resins. That is why the urea polymer foams are used here below to exemplify the principles of optimisation of the technology for production of polymer foam materials. 

---