System and method for continuously manufacturing cured membranes
AssigneeHolcim Technology Ltd
InventorsBruce Douglas, Michael Hubbard, Hao Wang
Life of this patent
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Abstract
A method of continuously manufacturing a cured membrane includes continuously compounding and mixing a vulcanizable rubber composition in a mixing extruder while continuously removing gasses from the vulcanizable rubber composition during mixing with a vacuum. The vulcanizable rubber composition may be continuously extruded to form an extrudate, which may be continuously calendered to form a green membrane. The green membrane may be continuously cured, such as by a hot air conveyor curing system, to form a cured membrane.
Claims12
A method of continuously manufacturing a partially-cured extrudate, the method comprising:
- (i) providing a mixing extruder including a feed throat, a downstream inlet that is downstream of the feed throat, and a material outlet, where the extruder has a length extending from the feed throat to the material outlet, said extruder including a mixing and conveying zone;
- (ii) introducing EPDM polymer, filler, and oil into the mixing and conveying zone through the feed throat to thereby form a mixture within the mixing and conveying zone;
- (iii) conveying the mixture through the mixing and conveying zone toward the material outlet, where said step of conveying the mixture includes back-mixing the mixture at a location along the length of the extruder;
- (iv) introducing a curative into the downstream inlet to thereby introduce the curative into the mixture;
- (v) partially curing the EPDM within the mixing and conveying zone to thereby form a partially-cured composition;
- and
- (vi) extruding the partially-cured composition into a partially-cured sheet, where the temperature of the partially-cured composition is between 120° and 160° C. at said step of extruding.
A partially-cured EPDM sheet formed by a method comprising the steps of:
- (i) providing a mixing extruder including a feed throat, a downstream inlet that is downstream of the feed throat, and a material outlet, where the extruder has a length extending from the feed throat to the material outlet, said extruder including a mixing and conveying zone;
- (ii) introducing EPDM polymer, filler, and oil into the mixing and conveying zone through the feed throat to thereby form a mixture within the mixing and conveying zone;
- (iii) conveying the mixture through the mixing and conveying zone toward the material outlet, where said step of conveying the mixture includes back-mixing the mixture at a location along the length of the extruder;
- (iv) introducing a curative into the downstream inlet to thereby introduce the curative into the mixture;
- (v) partially curing the EPDM within the mixing and conveying zone to thereby form a partially-cured composition;
- and
- (vi) extruding the partially-cured composition into a partially-cured sheet, where the temperature of the partially-cured composition is between 120° and 160° C. at said step of extruding.
Dependencies are inferred from the claim text.