Casting moulds and sand cores prodn. - using phenolic resol binder with methanol soln. of crystal hydrate benzene sulphonic acid as catalyst

摘要

Casting moulds and cores are made from a mixt. of 100 pts. wt. of a fire resistant filler, 1-3 pts. wt. of a phenol formaldehyde resol binder resins and 0.4-2.0 pts. wt. of an acid catalyst consisting of an 80-92% soln. of crystal hydrate benzene sulphonic acid (I) in methanol. The compsns. are cold curing materials suitable for the prodn. of moulds and cores, for mass prodn. and long series prodn. processes. Knocking out and cleaning up of the castings is reduced to a minimum. The use of a soln. of (I) in methanol as catalyst allows accurate metering of the (I) and does not adversely affect the physical and mechanical properties of the cured resin, as do aq. solns. of (I).