Kaneyoshi Ashida

Novel Methods of Smoke Suppression in Isocyanurate Foams (II) Modification by Silicon-containing Compounds

I n a previous paper (1), a method of smoke suppression for isocyanurate foams by means of the addition of aromatic aldehydes into their ingredients was described. Although the method exhibited remarkable improvements in some properties, i.e., smoke suppression, higher flame resistance and lower flame-spread rating, the resultant foams had the disadvantages of unsatisfactory friability. This paper deals with another method of smoke suppression for isocyanurate foams by the use of silicon-containing organic compounds as smoke suppressing agents, aiming at a foam which satisfies simultaneously the following requirements: reduced smoke generation, higher flame resistance, lower toxicity, lower friability and lower flame-spread rating. In other words, this study has been directed towards the methods of smoke suppression for isocyanurate foams without the loss of their superior properties.

Novel Methods of Smoke

ous problems in recent years, since they restrict the use of the foam in building applications. The hazards pointed out by fire prevention authorities are: (1) It impedes the escape or the rescue of occupants and causes possible panic. (2) It hinders fire fighting efforts. (3) The accompanying hot, toxic gases can be lethal even in areas remote from the flame front. (4) Certain constituents, such as acid gases, may damage property. Among the above-mentioned smoke hazards, it is emphasized in Japan that dense smoke makes it impossible for occupants to find an exit and results in death. Therefore, the Japanese new building code requires not only flame retardancy but also a lowering of smoke generation and toxic gases generated from building materials. At present, similar regulations are coming out also in American and European countries. Accordingly, the smoke suppression of urethane and isocyanurate foams has become one of the foremost concerns worldwide.

RIM and RRIM Development in Japan

The use of RIM products in the automotive industry in Japan was started by the stimulus of the successful use of RIM bumpers in the United States. The first use of RIM bumpers in Japan was seen in the Toyota Celica in 1977 and was followed by Mitsubishi cars in 1978, Nissan (Datsun) cars in 1979 and Mazda cars in 1980. The major use of RIM in the Japanese automotive industry, therefore, is in the production of bumpers. To a lesser extent it is used in such automotive parts as dash boards, steering wheels, etc. The major non-automotive uses of RIM are in ski cores and computer housings. The total usage of automotive RIM parts in 1979 amounted to approximately 7,000 metric tons; total usage of non-automotive RIM or rigid RIM foams amounted to approximately 1,000 metric tons. The consumption of various RIM products in Japan in 1979 is shown in Figure 1.

Full Scale Investigation of The Fire Performance of Urethane Foam Cushions Using Novoloid Fiber Products as Interlayer

Because of their serious fire hazards, however, many efforts are being devoted to improve their flame resistance. So far, flame retardant urethane foams are prepared either by the use of flame retarding raw materials or by after treatment of foamed products. These attempts, however, are not satisfactory, and substantially flame resistant flexible urethane foams are not yet produced without sacrificing some of its cushioning and creep properties. A great amount of black and dense smoke and toxic gases are often generated when urethane foam is burnt, which are, as recently pointed out, to be a