| 摘要 |
<p>The invention relates to foamable polymer materials which may be converted upon heating into foam materials, particularly polymeric foam materials having a polyacrylimide or polymethacrylimide structure. The foamable polymer materials are defined as comprising A) a copolymer containing at least 20% by weight of units of acrylic and/or methacrylic acid, together with units of at least one further polymerisable comonomer; the said copolymer further containing 0.01 to 5% by weight of units of at least one metal salt of acrylic or methacrylic acid, and B) a propellant which is compatible with the said copolymer A). They may be prepared by a process which comprises radically polymerising a monomer composition comprising at least 20% by weight of acrylic and/or methacrylic acid, together with at least one further polymerisable comonomer, and also 0.01 to 5% by weight of at least one metal salt of acrylic or methacrylic acid, the said composition also containing a propellant which is compatible with the remainder of the composition and also with the resulting polymer. The foam materials produced by the method according to the present invention are particularly suitable for preparing laminated structures (sandwich elements).</p> |
