Manufacture Of Polyurethanes Research Articles

Outcome of asthma induced by isocyanates

Isocyanates are widely used in industry for the manufacture of polyurethanes. Although they are recognized as an important cause of occupational asthma, it is unclear whether asthma persists after avoidance of exposure. We have followed up 50 cases, all of whom had avoided exposure for at least 4 years. At follow-up, 82% continued to have respiratory symptoms and approximately half of these required treatment at least once per week. These results indicate that a significant proportion of those with isocyanate-induced asthma are likely to have persisting symptoms for at least several years after exposure is avoided.

Classical syndromes in occupational medicine: dimethylaminopropionitrile.

Dimethylaminopropionitrile, used as a catalyst in the manufacture of polyurethane, was responsible for two epidemics of urinary retention, sexual dysfunction, and peripheral neuropathy in 1978. Most affected workers recovered promptly, but some have had persisting neuropathy, sexual and bladder dysfunction, and CNS symptoms. The mechanism of neurotoxicity appears to be interference with axoplasmic transport. The catalyst that caused the problem was withdrawn from the market after swift governmental action.

Recycling of polyurethane and polyisocyanurate foam

AbstractHeating of isocyanate derived foams with glycol mixtures is a simple and economically attractive recycling process. The process is emission free, not sensitive to varying product mixes and the obtained polyols can be completely reused in the manufacture of rigid polyurethane or polyisocyanurate foam.

The determination of adjacent oxypropylene–oxyethylene units in propylene oxide–ethylene oxide adducts by infrared spectroscopy

AbstractA study of several base‐catalyzed propylene oxide—ethylene oxide adducts of glycerin and certain model compounds has shown that an infrared absorption band at 10.30 μ can be associated with a structural entity represented by an oxyethylene unit attached to an oxypropylene unit at the secondary position. Coupled with other information such as total oxyethylene content and primary hydroxyl content, this finding has proved most useful in differentiating average molecular structure for commercial polyether polyols used in the manufacture of polyurethanes.

Toluene Di-Isocyanate (TDI) Toxicity

TOLUENE di-isocyanate, or tolylenedi-isocyanate (TDI), is a compound widely used today in the manufacture of polyurethane. Since the description of a procedure published by Bayer1 in 1947 polyisocyanates have been brought into interactions with a resin, and polyurethane obtained as the end product. If polyurethane contains carbon dioxide in varying quantities, depending upon the polyisocyanates and resins selected, it assumes a foamy character. Commercial tolylenedi-isocyanate, a liquid at room temperature, is usually a mixture of 2 isomers; it has a pungent, acrid odor, its color varies from colorless to a light green, its vapor pressure is 0.04 mm. at 20°C., . . .