Lining for lightweight fiberglas reinforced polyester resin mold

Claim 1

A FORM MEMBER OF EXTENDED SURFACE AREA FOR POURED CONCRETE STRUCTURES COMPRISING: (A) A BACKING FORMED OF A RIGID, GLASS FIBER REINFORCED, CURED STYRENE-POLYESTER LAMINATE; AND, (B) A CHEMICALLY INERT FINELY DIVIDED HYDROPHILIC FIBROUS FILLER CONTAINING CURED STYRENE-POLYESTER GEL FACING LAYER BONDED TO SAID BACKING, SAID FACING LAYER VARYING IN THICKNESS FROM ABOUT 1/64" TO ABOUT 1/4", SAID FACING LAYER IMPARTING A SMOOTH SURFACE TO THE POURED CONCRETE MOLDED THEREBY AND BEING ADAPTED TO WITHDRAW FROM THE FRESHLY POURED CONCRETE A QUANTITY OF WATER UP TO ABOUT 1.5% BY WEIGHT OF THE CURED GEL FACING LAYER TO CONDITION THE MOLD AND TO THEREBY FACILITATE SEPARATION OF THE MOLD FORM FROM THE CONCRETE AFTER THE CONCRETE HAS HARDENED, THERE BEING PRESENT IN SAID GEL FACING AT LEAST FROM ABOUT 15 TO ABOUT 35% OF SAID FIBROUS TALC FILLER OF PARTICLE SIZE OF 1-10 MICRONS BY WEIGHT OF SAID FACING LAYER, SAID FILLED STYRENE-POLYESTER GEL FACING LAYER BEING COATED WITH A FILM OF ORGANIC HYDROPHOBIC MOLD-RELEASE MATERIAL, SAID HYDROPHOBIC FILM FORMING A BARRIER WHICH BLOCKS THE TRANSPORT OF FREE LIME FROM THE CONCRETE WHILE FLOATING AGAINST A FILM OF WATER AT THE WATER-CONTAINING SURFACE OF THE CONCRETE DURING CASTING, THE CONCRETE BEING THEREBY EFFECTIVELY SEPARATED FROM THE MOLD BY A FILM OF WATER.