Liquid foams of reinforced unsaturated polyester resins and process for making the same

Claim 1

A continuous process for making fiber-reinforced foams which are suitable for transforming into reinforced solid cellular materials having a density lower than 0.7 kg/l if no inert filler material is present or a density lower than 1 kg/l if inert fillers are present as well, said process essentially comprising: (1) mixing together an unsaturated polyester resin, a reinforcing material and, optionally an inert filler, said reinforcing material being selected from the group consisting of synthetic fibers, vegetable fibers and mineral fibers having a maximum length of 3 mm, whereby a liquid mixture is obtained; (2) transferring said liquid mixture of reinforcing material, unsaturated polyester resin and, optionally, said inert filler to a turbine having a free internal volume of at least 2 liters and comprising a rotor and a stator, both having either prismatic or cylindrical projections, said turbine rotor having a peripheral speed of greater than 200 m/min and; thereafter (3) introducing a gas into said turbine at a pressure of from 1.1 to 10 absolute atmospheres, said turbine operating to distribute said gas in the form of small bubbles homogeneously and uniformly throughout said mixture, thereby producing a reinforced foam of unsaturated polyester resin, and thereafter discharging said reinforced foam from said turbine.