A synthetic polymer-liquefied propellant composition capable of forming a cold foamed structure having a temperature at least 30.degree. C. below the ambient temperature at which the cold foamed structure is formed, and containing open and/or closed cells, which may contain an additive which is deposited in the pores and/or walls of the foamed structure as the foamed structure is formed, comprising, as the essential ingredients:
- (a) a film-forming synthetic polymer in an amount within the range from about 2% to about 30% by weight of the composition;
- (b) at least one liquefied propellant boiling below -10.degree. C.;
- (c) the total propellant being in an amount within the range from about 50% to about 90% by weight of the composition;
- and having a heat vaporization of at least 55 calories per gram;
- the propellant being capable of dissolving the synthetic polymer at least in the presence of a co-solvent that is soluble in the propellant and in solutions of the synthetic polymer in the propellant at ambient temperature;
- and
- (d) at least one nonsolvent that is soluble in the propellant but in which the synthetic polymer is insoluble in an amount within the range from about 1% to about 85% by weight of the composition;
- the composition forming on volatilization of propellant at ambient temperature a coherent foamed structure containing open and/or closed cells, and having a temperature at least 30.degree. C. below ambient temperature.