| abstract |
Premixes intended for the preparation of polyurethane or polyisocyanurate foams, comprise at least one polyol, at least one hydrofluoroalkane corresponding to the general formula CF3-CR1R2-CF2-R3 where R1 and R2 independently represent a hydrogen atom or a C1-C3 alkyl group, optionally fluorinated, and where R3 represents a hydrogen atom or a methyl group; and at least one stabilizer chosen from nitroalkanes, diketones, alkaline earth metal salts and brominated compounds. |