GB827032A - Modified acrolein-pentaerythritol resins and a process for their preparation - Google Patents

Abstract

Liquid A-stage condensates formed by reacting 1.3-1.9 mols of acrolein with 1 mol. of pentaerythritol in the presence of an acid catalyst are modified by the addition of either 2-25% of 3,9-divinylspirobi-(m-dioxane), viz.: <FORM:0827032/IV (a)/1> or 2-15% of acrolein dimer, viz.: <FORM:0827032/IV (a)/2> the proportions being by weight of the total composition. The A-stage condensates are prepared at 60-100 DEG C. and the volatiles are then stripped off to produce condensates of low (5000-25,000 c.p.s. at 40 DEG C.) or high viscosity (25,000-500,000 c.p.s. at 40 DEG C.). If HCl is used as the initial catalyst, the modifiers are normally added with such curing catalysts as sulphuric, toluene sulphonic, benzene sulphonic, phosphoric or mixed alkane-sulphonic (primarily ethanebut also containing methane- and propane-) acids, stannic, aluminium or ferric chloride, boron trifluoride, or titanium tetrachloride. If, on the other hand, another acid is used as the initial catalyst, e.g. sulphuric, benzene sulphonic, or toluene sulphonic, that acid will itself function as the curing catalyst; or alternatively, it may be neutralized with sodium carbonate or acetate, and an appropriate curing catalyst added later. In either case curing takes place at 50-200 DEG C. As the spirobi compound melts at about 43 DEG C. it is preferably added at temperatures of 45 DEG C. or higher. Uses.-Display signs, ornaments, fixtures, dentures, sealing and potting electrical components, glass cloth laminates. Specifications 720,954, [Group XIV], and 822,668 are referred to.