FOAMING ADDITIVE FOR PRODUCING POLYURETHANE FOAM, AND METHOD FOR PRODUCING RIGID POLYURETHANE FOAM BY USING IT

To provide a foaming additive for producing a polyurethane foam, which is capable of solving a problem of deterioration of moldability due to deterioration of the initial foaming property of a foam, and a method for producing a rigid polyurethane foam by using it. A foaming additive for producing a polyurethane foam, is used which comprises a salt of carbon dioxide with an amine compound of one or more types selected from the group consisting of an amine compound (I) represented by the following formula (1): wherein each of R1 to R4 which are independent of one another, is a hydrogen atom or a methyl group, and n is a number of at least 1, an amine compound (II) represented by the following formula (2): wherein each of R1 to R4 which are independent of one another, is a hydrogen atom or a C1-3 alkyl group, R5 is a hydrogen atom, a C1-3 alkyl group, a C1-3 aminoalkyl group, a C2-4 N-methylaminoalkyl group or a C3-5 N,N-dimethylaminoalkyl group, or R5 may be optionally bonded to R1, R2, R3 or R4 to form a cyclic compound having a piperazine structure, provided that at least one of R1 to R5 is a hydrogen atom, and all of R1 to R5 are not hydrogen atoms, each of n and m which are independent of each other, is an integer of from 1 to 5, and a is an integer of from 1 to 6, an amine compound (III) represented by the following formula (3): wherein R1 is a C1-4 alkyl group, and each of R2 to R5 which are independent of one another, is a hydrogen atom or a methyl group, an amine compound (IV) represented by the following formula (4): wherein R1 is a C1-4 alkyl group, and each of R2 to R5 which are independent of one another, is a hydrogen atom or a methyl group, and an amine compound (V) represented by the following formula (5): wherein each of R2 to R5 which are independent of one another, is a hydrogen atom or a methyl group.