PURPOSE: To improve the productivity and workability by using a hardening catalyst consisting of a strong acid salt of hexamethylene tetraamine and having a reactivity sufficiently different between in cooling and in heating in the hardening of amino plastic resin.
CONSTITUTION: A strong acid salt of hexamethylene tetraamine is added as hardening catalyst to amino plastic resin (e.g.; urea formaldehyde resin) to harden the resin. Thus, the hardening speed of the resin can be regulated so that the hardening is not excessively quickly progressed, and the resin can be quickly hardened by heating and pressurizing within a press when a particle board is manufactured by this resin. The manufacture of the strong acid salt of hexamethylene tetraamine is attained by mixing a heated formaldehyde aqueous solution with an ammonia aqueous solution so that the mole ratio of formaldehyde/ammonia is 1.5, and adding a strong acid thereto so that pH is 1-7.
JIYATSUKU RARO
ANDORE BUINIYOO
