Elastomers reinforced with siliceous fillers

Claim 2

AN IMPROVED ELASTOMERIC COMPOSITION WHICH WHEN VULCANIZED HAS IMPROVED PROPERTIES, SAID COMPOSITION CONSISTING OF A SOLID ELASTOMER SELECTED FROM THE GROUP CONSISTING OF RUBBER, COPOLYMERS OF BUTADIENE STYRENE, POLYBUTADIENE, BUTYL RUBBER, CIS-POLYISOPRENE, POLYCHLOROPRENE, TERNARY POLYMERS OF ETHYLENE-PROPYLENE-DIENE MONOMERS, AND COMBINATIONS THEREOF; A SILICEOUS FILLER SELECTED FROM THE GROUP CONSISTING OF CLAYS, KAOLINS, PRECIPITATED SILICATES, THERMAL SILICAS, PRECIPITATED SILICOALUMINATES, PRECIPITATED CALCIUM SILICATES AND COMBINATIONS THEREOF; SAID SILICEOUS FILLER BEING PRESENT IN AN AMOUNT SUCH THAT THE PERCENTAGE BY WEIGHT OF SAID SILICEOUS FILLER WITH RESPECT TO THE ELASTOMER IS IN THE RANGE OF BETWEEN 5 AND 250%; AND AS AN ADDITIVE, POLYVINYL ALCOHOL, SAID POLYVINYL ALCOHOL COMPRISING BETWEEN ABOUT 0.5 AND 20% BY WEIGHT OF THE ELASTOMER AND FROM ABOUT 0.5 TO 10% BY WEIGHT OF THE SILICEOUS FILLER, AND SAID POLYVINYL ALCOHOL REMAINING IN A FREE STATE TO MAINTAIN ALL OF ITS SOLUBILITY IN WATER.

Claim 3

In a process wherein the properties of a solid elastomer selected from the group consisting of natural rubber, copolymers of butadiene styrene, polybutadiene, butyl rubber, cispolyisoprene, polychloroprene, ternary polymers of ethylenepropylene-diene monomers, and combinations thereof are improved by the incorporation, prior to vulcanization, of a siliceous filler, the improvement comprising incorporating a siliceous filler with said elastomer prior to vulcanization, said siliceous filler being selected from the group consisting of clays, kaolins, precipitated silicas, thermal silicas, precipitated silicoaluminates, precipitated calcium silicates and combinations thereof, and being added in an amount such that the percentage by weight of said siliceous filler with respect to said elastomer is in the range of between 5 to 250%, said improvement further comprising adding polyvinyl alcohol to the composition consisting of said elastomer and said siliceous filler prior to vulcanization to thereby obtain a mixture having a high level of a siliceous filler and which, when vulcanized, has improved properties including permanent set upon compression aNd increased hardness, modulus and tear resistance; said polyvinyl alcohol being added to said mixture of said elastomer and filler, prior to vulcanization, in an amount such that its percentage by weight is between 0.5 to 20% by weight of said elastomer and between 0.5 and 10% by weight of said siliceous filler, and said polyvinyl alcohol remaining in a free state to maintain all of its solubility in water.

Claim 4

In a process wherein the properties of a solid elastomer selected from the group consisting of natural rubber, copolymers of butadiene styrene, polybutadiene, butyl rubber, cispolyisoprene, polychloroprene, ternary polymers of ethylenepropylene-diene monomers, and combinations thereof are improved by the incorporation, prior to vulcanization, of a siliceous filler, the improvement comprising incorporating a siliceous filler with said elastomer prior to vulcanization, said siliceous filler being selected from the group consisting of clays, kaolins, precipitated silicas, thermal silicas, precipitated silicoaluminates, precipitated calcium silicates and combinations thereof, and being added in an amount such that the percentage by weight of said siliceous filler with respect to said elastomer is in the range of between 5 to 250%, said improvement further comprising adding polyvinyl alcohol to the composition consisting of said elastomer and said siliceous filler prior to vulcanization to thereby obtain a mixture having a high level of a siliceous filler and which, when vulcanized, has improved properties including permanent set upon compression aNd increased hardness, modulus and tear resistance; said polyvinyl alcohol being added to said mixture of said elastomer and filler, prior to vulcanization, in an amount such that its percentage by weight is between 0.5 to 20% by weight of said elastomer and between 0.5 and 10% by weight of said siliceous filler, and said polyvinyl alcohol remaining in a free state to maintain all of its solubility in water.