Laser-induced plastic foaming

An additive for a matrix material made of plastic or paint, varnish or lacquer for a foaming of the matrix material which can be triggered by irradiation with laser light or IR light, wherein the additive comprises at least the following constituents:

• a) at least one absorber material which, when embedded or dissolved in the matrix material, absorbs laser light or IR light and brings about local heating in the matrix material at the site of the irradiation with laser light or IR light, and
• b) at least one blowing agent which, when heated due to the irradiation with laser light or IR light to temperatures above 50° C., produces, by decomposition, chemical conversion or reaction, a gas which foams the matrix material,
• wherein the at least one blowing agent is at least one carbon dioxide carrier in combination with at least one acid carrier which produce CO2 gas during decomposition and/or reaction, wherein the carbon dioxide carrier is selected from the group consisting of carbonates, hydrogen carbonates, and carbamates of the alkali metals, alkaline earth metals, aluminum, transition metals and ammonium, and mixtures of the above, and the acid carrier is selected from the group consisting of phosphates, condensed phosphates, phosphonates, phosphites, mixed hydroxide phosphates, and cyanurates, carboxylic acids and salts thereof, and mixtures of the above, and
• wherein the at least one absorber material is selected from the group consisting of the following:
• i) phosphates, condensed phosphates, phosphonates, phosphites and mixed hydroxide-phosphate-oxoanions of metals which are selected from the group consisting of the elements of the 3rd to 6th period of main groups II and III, of the 5th to 6th period of main group IV and of the 4th to 5th period of sub-groups III to VIII and the lanthanides of the periodic table of the elements,
• ii) platelike pigments of metal selected from the group consisting of Al, Cr, Fe, Au and Ag, uncoated or covered with one or more metal oxide layers, wherein the metal oxide is selected from the group consisting of titanium dioxide, antimony(III) oxide, zinc oxide, tin oxide, zirconium dioxide, chromium oxide, nickel oxide, copper oxide, cobalt oxide, and iron oxide (Fe2O3, Fe3O4), and
• iii) organic absorbers selected from the group consisting of phthalocyanines and naphthalocyanines.