The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Mar. 28, 1989

Filed:

Aug. 27, 1987
Applicant:
Inventors:

Sung W Hong, Cheshire, CT (US);

Gilles J Page, Enfield, CT (US);

Assignee:
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
B29C / ; B32B / ;
U.S. Cl.
CPC ...
15624411 ; 15624423 ; 15624424 ; 152502 ; 152504 ; 152505 ;
Abstract

A process is disclosed for extruding a flat strip of uniformly thick sealant stock from an extruder which extrudes the sealant stock with a rotary helical action. The stock consists essentially of a vulcanizable mixture of a high molecular weight (mol wt) elastomer, a low mol wt elastomer, a curing agent and a processing aid selected from a tackifier and a homogenizer. The strip is less than about 10 mm thick, and at least 10 times as wide as it is thick. The stock does not flow and cannot be poured even at 212.degree. F. The stock is supplied to the extruder by a reciprocating pump which maintains an intermittent pressure yet provides the required uniform thickness of strip. Each component of the stock strongly adheres to any surface, to all metal surfaces and to each other, making it difficult to obtain a homogeneous mixture. The rate at which the strip is discharged from the extruder is maintained substantially constant, and its thickness controlled by the speed of a horizontal endless belt conveyor onto which the vertically hanging strip is continuously discharged. A spray coating of aqueous polyvinyl alcohol, which is then dried, leaves a detackified surface without which the extrudate could not be handled.


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