Bridgestone Corporation

Bridgestone/firestone, Inc.

The Firestone Tire & Rubber Company

Arthur W Greenstreet

Charles D Spragg

Georg G Bohm

Gregory D Chaplin

William L Hergenrother

Gerardo P Elia

Joseph C Norka

A compact and precision extrusion system for extruding strips of rubber compounds with profiles of accurate dimensions. Strips of rubber compound are uniformly heated and mixed in an extruder and then passed through a low pressure drop strainer to remove foreign matter. The strained compound then is fed directly into a gear pump which delivers precise volumes of the rubber compound immediately into the spread chamber of an extrusion head after which it passes through a die to form a precise strip of the rubber compound. The strainer and extrusion head are movably mounted with respect to the gear pump for axial separation from the gear pump for easy removal of the rubber compound from the various components of the system to facilitate compound changes. A control system regulates the speed of the extruder to provide a near constant pressure at the entrance port of the gear pump to precisely regulate the rate of extrusion of the compound from the extrusion head. The extruder preferably includes a feed section, a pressure generation section, and a mix section which maintain the temperature of the rubber compound below 100.degree. C.

Compact precision extrusion system

A compact and precision extrusion system and method for extruding strips of rubber compounds with profiles of accurate dimensions. Strips of rubber compound are uniformly heated and mixed in an extruder and then passed through a low pressure drop strainer to remove foreign matter. The strained compound then is fed directly into a gear pump which delivers precise volumes of the rubber compound immediately into the spread chamber of an extrusion head after which it passes through a die to form a precise strip of the rubber compound. The strainer and extrusion head are movably mounted with respect to the gear pump for axial separation from the gear pump for easy removal of the rubber compound from the various components of the system to facilitate compound changes. A control system regulates the speed of the extruder to provide a near constant pressure at the entrance port of the gear pump to precisely regulate the rate of extrusion of the compound from the extrusion head. The extruder preferably includes a feed section, a pressure generation section, and a mix section which maintain the temperature of the rubber compound below 100.degree. C.

Compact precision extrusion method

A gear metering pump for delivering precise amounts of a compounded elastomeric material into a die. The gear pump has a housing formed with a hollow interior chamber containing a pair of rotating meshing gears mounted on shafts, one of which is power driven, for passing controlled quantities of the compounded material out of the chamber and into the die. A side plate is removably mounted on the housing and encloses an open side of the chamber and is moved between open and closed positions by fluid pressure cylinders mounted on the housing to provide ready access into the chamber for cleanout. A first bearing assembly for the gear shafts is mounted on the removable side plate and retains the gears mounted thereon for removing the gears from within the chamber along with the side plate. Outlet openings are formed in the removable side plate and in an opposite fixed side plate adjacent the shafts and bearings, permitting small quantities of the compounded material to flow between the shafts and bearings and out of the openings for lubrication of the bearings. The drive shaft passes out of the housing through an enlarged opening and is free of any end seal with the housing to reduce heat buildup.

Gear metering pump for compounded elastomeric material

A screen assembly for mounting on the outlet end of an extruder for removing foreign particles from an elastomeric material being discharged from the extruder. The assembly includes a screen support member having a plurality of spaced elongated ribs formed integrally with or removably mounted on a surrounding member. The spaced ribs form a plurality of elongated slots therebetween which provide flow paths for the elastomeric material, and preferably are concavely-shaped in the direction of travel of the extruded material. A mesh screen formed of a high tensile strength, work hardened stainless steel wire cloth is formed complementary to the concavity of the ribs and is mounted in juxtaposition to the ribs for removing the foreign particles as the elastomeric material passes through the screen. The concavity of the ribs and formation of the elongated material flow paths, reduce the amount of back pressure created in the elastomeric material and reduces the bending and shear forces created on the ribs and surrounding support member.

Screen assembly for screening elastomeric material

A process for the rapid bulk polymerization of polybutadiene/nylon-6 block copolymers comprises the steps of preparing a mixture comprising from about 100 to about 50 parts by weight of a low molecular weight polybutadiene terminated by an isocyanate or isothiocyanate and end-capped with caprolactam providing a stable imide type terminated polymer, with from about 0 to about 50 parts by weight of a dry non-cold flowing rubber neutralized with caprolactam, charging the polymer mixture without hydrolyzing the end-capped polybutadiene to a reaction vessel with caprolactam and polymerizing the caprolactam at a temperature sufficient to flash off any solvents introduced during the step of preparing to form a block copolymer with the end-capped polybutadiene. The process of the present invention is also applicable to the rapid polymerization of other block copolymers formed from anionically polymerized cold flowing rubbers terminated by a compound selected from the group consisting of isocyanates and isothiocyanates and end-capped with an amide containing compound providing a stable imide type terminated rubber and mixed with a non-cold flowing rubber terminated with an amide containing compound which mixture is then charged to a reaction vessel without hydrolyzation with a monomer having an active hydrogen other than a monomer utilized to form a polymer present in the polymer mixture and polymerizing the monomer at a temperature sufficient to flash off any solvents introduced during the step of preparing.

Growing community of inventors

Clinton, OH, United States of America

Arthur W Greenstreet