Nontacky shaped objects from polymer latices
AssigneeE. I. Du Pont de Nemours and Company
InventorMark J. Marquisee
Life of this patent
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Abstract
Nontacky, elastomeric shaped objects (e.g., pellets or filaments) comprising a normally tacky, uncured elastomer having an integral, porous coating of silicic or aluminic acid polymer can be prepared by bringing shaped bodies of a normally tacky, uncured elastomer latex into contact with an aqueous bath containing a soluble coagulating salt for the latex, and a silicic or aluminic acid polymer, and washing and drying the resulting coated shaped objects. The shaped objects are highly porous before washing and drying, and some porosity remains even after washing and drying.
Claims20
A method of preparing nontacky, elastomeric shaped objects which comprises bringing shaped bodies of a normally tacky, uncured elastomer latex having a solids content of 20% to 65% by weight into contact with an aqueous bath containing, based on the total weight of the bath,
- (a) 0.5 to 25% by weight of a soluble coagulating salt for the latex, and
- (b) 0.01 to 5% by weight of a soluble or colloidally dispersed, hydrous, inorganic oxide selected from the group consisting of silicic acid polymers aluminic acid polymers, silicic acid-aluminic acid copolymers, and mixtures thereof,
- said bath having a pH of 2 to 7 such that, when a drop of 1.0 N NaOH is added to the bath, the drop is immediately surrounded by a cloudy coating of gelled, hydrous, inorganic oxide, thereby coagulating the latex and forming highly porous shaped objects of the coagulated elastomer coated with water insoluble, hydrous, inorganic oxide.
A coagulating and coating bath which comprises,
- (a) 0.5 to 25% by weight of a soluble coagulating salt for a normally tacky, uncured elastomer latex, and
- (b) 0.01 to 5% by weight of a soluble or colloidally dispersed, hydrous, inorganic oxide selected from the group consisting of silicic acid polymers, aluminic acid polymers, silicic acid-aluminic acid copolymers, and mixtures thereof,
- said bath having a pH of 2 to 7 such that, when a drop of 1.0 N NaOH is added to the bath, the drop is immediately surrounded by a cloudy coating of gelled, hydrous inorganic oxide.
Dependencies are inferred from the claim text.