GB1112410A - Batch mixer for foamable compositions - Google Patents

Abstract

Reactive foam-forming ingredients are mixed in a process wherein the ingredients are provided as first and second stocks of material which are individually stable but adapted to interact on mixing to form a foam, which comprises as a repeated sequence, the steps of measuring a portion of the first material into a mixing vessel, measuring a portion of the second material into said vessel, mixing the two portions in the vessel, discharging the mixed portions from the vessel prior to substantial progress of the reaction and measuring the portion of the first material for the following mixing cycle into the mixing vessel, the first material acting to dilute the residue of the preceding mixed portions remaining in the mixing vessel. Preferably the first stock is catalyst-free and the second stock is catalyst-containing. An apparatus for carrying out the process is provided. In the Examples are used (1) mixture A:3,4-dihydro-2H-pyran-2-methyl-(3,4 dihydro - 2H - pyran - 2 - carboxylate), a prepolymer of this compound and 2:2-di - p - hydroxy - phenyl propane, a condensate of epichlorohydrin and 2:2 - di - p - hydroxyphenyl propane, siloxane oxyalkylene copolymer surfactant and trichloromonofluoromethane and methane diphenyl diisocyanate; mixture B: phenolic novolate resin, polypropylene glycol, trichloromonofluoromethane and boron trifluoride etherate. (2) Mixture A: 3,4 - dihydro - 2H - pyran - 2 - methyl - (3,4 - dihydro - 2H - pyran - 2 - carboxylate), 2:2 - di - p - hydroxyphenyl propane, 2:2 - bis-(31,51 - dibromo - 41 - hydroxyphenyl) propane, siloxane surfactant and trichloromonofluoromethane and methane diphenyl diisocyanate; mixture B: as (1).