摘要:
A perfected process for the production of expanded plastic materials, comprising a hot moulding phase of a starting polymeric blend inside a mould, wherein the heating of said blend is effected by making the same a heat source, by triggering an exothermic reaction in its interior. With respect to the known art in the field, the process of the invention allows an improvement in the heating of the polymeric mass inside the mould, reducing the times necessary for effecting it and homogenizing the thermal values inside this mass.
摘要:
Formulation for cellular, foamed-polymer product based on polyvinyl chloride, comprising: a polyvinyl chloride homopolymer having a K-value of from 60 to 85 and a pH value of the aqueous extract ranging of from 8 to 12; at least one isocyanate selected from isomers and homologues of diphenylmethane-4,4′-diisocyanate and modified diphenylmethane-4,4-diisocyanate s and mixtures thereof; at least one anhydride selected from the group of succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl-tetrahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, cyclohexane-1,2-dicarboxylic anhydride, methyl-endomethylene tetrahydrophthalic anhydride, dodecenyl succinic anhydride, trimellitic anhydride and mixtures thereof; at least a surfactant; at least a foaming agent.
摘要:
A process for the production of expanded PVC of the type includes heating a mass of polymeric mixture inside a closed mold; controlling the expansion of the mass in an environment having a constant volume defined by the closed mold, control being performed by the presence, in the mass of polymeric mixture, of microparticles of a compressible material, suitable for being contracted, under the action of the pressure generated by the formation and expansion of microcells of expanding gas in the same mass, from an initial form having a larger volume, to a form having a smaller volume; and expanding the microparticles, from their configuration to the initial configuration, the density of the expanded material thus obtained being determined by the contemporary presence of both microcells of expanding gas and the microparticles in their configuration having a larger volume.
摘要:
A perfected process for the production of expanded plastic materials, comprising a hot molding phase of a starting polymeric blend inside a mold, wherein the heating of said blend is effected by making the same a heat source, by triggering an exothermic reaction in its interior. With respect to the known art in the field, the process of the invention allows an improvement in the heating of the polymeric mass inside the mold, reducing the times necessary for effecting it and homogenizing the thermal values inside this mass.
摘要:
A process for the production of expanded PVC of the type includes heating a mass of polymeric mixture inside a closed mold; controlling the expansion of the mass in an environment having a constant volume defined by the closed mold, control being performed by the presence, in the mass of polymeric mixture, of microparticles of a compressible material, suitable for being contracted, under the action of the pressure generated by the formation and expansion of microcells of expanding gas in the same mass, from an initial form having a larger volume, to a form having a smaller volume; and expanding the microparticles, from their configuration to the initial configuration, the density of the expanded material thus obtained being determined by the contemporary presence of both microcells of expanding gas and the microparticles in their configuration having a larger volume.
摘要:
Formulation for cellular, foamed-polymer product based on polyvinyl chloride, comprising: a polyvinyl chloride homopolymer having a K-value of from 60 to 85 and a pH value of the aqueous extract ranging of from 8 to 12; at least one isocyanate selected from isomers and homologues of diphenylmethane-4,4′-diisocyanate and modified diphenylmethane-4,4-diisocyanate s and mixtures thereof; at least one anhydride selected from the group of succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl-tetrahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, cyclohexane-1,2-dicarboxylic anhydride, methyl-endomethylene tetrahydrophthalic anhydride, dodecenyl succinic anhydride, trimellitic anhydride and mixtures thereof; at least a surfactant; at least a foaming agent.