Process for preparing a particle board using a self-releasing binder comprising a polyisocyanate and a sulfur-containing release agent

Claim 1

In a process for the preparation of particle board wherein particles of material capable of being compacted are contacted with a polyisocyanate and the treated particles are subsequently formed into boards by the application of heat and pressure, the improvement which comprises imparting self-releasing properties to said particle board by contacting said particles, in addition to the treatment with said polyisocyanate, with from about 0.1 to about 20 parts, per 100 parts by weight of said polyisocyanate, of a sulfur-containing compound selected from the group consisting of (a) organic mono- and poly-sulfonic acids of the formulae: ##STR8## wherein n is an integer having a value of at least 2, (b) organic sulfonic acid anhydrides of the formula: ##STR9## (c) N,N-disubstituted taurates of the formula: ##STR10## (d) sulfo esters of the formula: ##STR11## (e) organic hydrogen sulfates of the formula: ##STR12## (f) alkanolamido alkane sulfate esters of the formula: ##STR13## and (g) alkali metal, alkaline earth metal, and heavy metal salts of the acids of formulae (I), (II), (IV), (V), (VI) and (VII); wherein, in the above formulae, R, R 1 and R 2 each independently represent alkyl having at least 6 carbon atoms, alkenyl having at least 6 carbon atoms, alkenyl substituted by carboxy and having at least 4 carbon atoms, alkyl as above defined and substituted by from 1 to 2 acyloxy groups wherein the acyl group is the residue of an aliphatic monocarboxylic acid having at least 2 carbon atoms, aryl, aryl substituted by at least one alkyl, and ##STR14## wherein R" is selected from the class consisting of alkyl, aryl and aryl substituted by at least one alkyl, one of A and B represents hydrogen and the other is selected from the class consisting of hydrogen, methyl, chloromethyl and 2,2,2-trichloromethyl, and m is a number having an average value from 1 to 25; R 3 is selected from the class consisting of methyl and ethyl; R 4 is selected from the class consisting of hydrogen and --CH 2 CH 2 OSO 3 H; and R' corresponds to the radical R having n-1 additional SO 3 H groups substituted therein.