摘要：

Hardener compsn. (I) is claimed, for urea-formaldehyde glue resins (II) contg. up to 20 wt.% melamine and up to 5 wt.% phenol. In addn. to an ammonium salt of an inorganic or organic acid, (I) also contains an acid (III) which does not react with (I), together with urea and, opt., a metal salt, and has pH above 2 in aq. soln.; or (I) contains, in addn. to these components, a glycol or its functional deriv. (IV), and has pH below 2 in aq. soln.. Metal salt is an alkali(ne earth) metal salt, pref. chloride or sulphate of Li, Na, Ca, or Mg; ammonium salt is chloride, sulphate, phosphate, nitrate, bromide, or formate; corresp. to the above alternatives, (III) is an acid with pKa above 3 at 25 deg.C, esp. formic acid, or an inorganic or organic acid with pKa below 3 at 25 deg.C; (IV) is ethylene-, diethylene-, or tri- or tetra-meric oligoethylene-glycol, or their ethers or esters or their mixts..

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