Included is a homogeneous sheet, which excludes polyvinylchloride. The sheet includes a polyurethane, a synthetic rubber blend, and a filler. The synthetic rubber blend may include a pre-mix of a synthetic rubber and white oil.

The invention relates to a system (100) for measurement quality verification (MQV) that forms part of an installation (10) located at a site that manufactures rubber mixtures, the system including: a weighing platform (102) having a scale (104) for determining a weight loss of the metered raw materials; a metering device (106) including: a metering hopper (108) that receives the raw materials required for performing one or more rubber mixing processes; and a metering means that meters the raw materials into the metering hopper in real time; an application and removal system that allows for application and removal of one or more calibration weights (118) relative to the weighing platform (102); and a motion system that facilitates reciprocating vertical movement of the metering device. The invention also relates to an installation (10) that incorporates the disclosed system and to a continuous metering process performed by the installation.

The invention relates to a screw extruder (29) having a housing (30) comprising an intake housing (4), a degassing housing (5), and at least one housing bore (21, 22) running in the interior of the degassing housing (5) and implementing at least one internal wall segment (25; 26; 27; 28) of the degassing housing (5) and serving for receiving at least one auger shaft (7), and wherein the at least one wall segment (25; 26; 27; 28) of the at least one housing bore (21, 22) comprises at least one partition wall (13, 33) protruding into the at least one housing bore (21, 22) in the region of the degassing housing (5), and wherein at least one filter element (8) is disposed in the interior of the degassing housing (5) and at least partially encompasses the at least one auger shaft (7) and bears on the partition wall (13) in regions for implementing at least two spatial pressure regions (11, 12) sealed off from each other.

An extruder (1) includes a cylinder (2) and a screw (3), and one or more front vents (8a) are provided on the cylinder (2) upstream of a hopper (5) and downstream of a rear vent (7). The cylinder (2) is provided with, between the hopper (5) and the rear vent (7), a liquid supply device (9) for spraying water into the cylinder (2) to cool an interior thereof and a liquid discharge port (12) that is opened in a lower portion of the cylinder (2).

Provided is a copolymer which has a mass average molecular weight (Mw) of 240,000 or greater and 3,500,000 or less, a structural unit derived from an acrylate (B1) and a structural unit derived from aromatic vinyl (B2), and a branched structure.

A chemical composition for a degradable polymeric material includes an isocyanate terminated polyester prepolymer, including prepolymer units as a main chain with a plurality of isocyanates at ends of the main chain, and a cross-linking agent. The isocyanate terminated polyester prepolymer has a structural formula as follows: ONC—R″—NH—[—CO—R—R′″-]n-NH—R″—CNO, wherein R′″ is selected from a group consisting of —O— and —CO—O—R′—O—, ##STR00001##
wherein R, R′ and R″ are an aryl group or alkyl group and wherein n is a number of prepolymer units corresponding to length of the main chain. The composition degrades at a rate and at a delay depending on temperature and the composition for a component of a downhole tool. The composition has strength and elasticity for a component of a downhole tool.

The invention relates to a process for devulcanizing a vulcanized rubber mixture, comprising the following steps: A) providing or producing a vulcanized rubber mixture, B) comminuting the vulcanized rubber mixture to a granular material composed of vulcanized rubber particles, where the vulcanized rubber particles have a maximum particle diameter of 100 mm, C) extruding the vulcanized rubber particles produced in step B) in a twin-screw extruder at a shear rate of less than 100 s.sup.−1, where the temperature of the vulcanized rubber particles during extrusion is less than 200° C., to give a devulcanized rubber mixture having a temperature above 100° C., D) cooling the devulcanized rubber mixture in a further kneading unit, so as to give a devulcanized rubber mixture having a temperature in the range from 50° C. to 100° C. The invention further relates to an apparatus for performing the process and to the use of the apparatus for devulcanization of a vulcanized rubber mixture.

A production line (200) for performing multi-pass mixing sequences of rubber mixtures has at least one first mixing line (200A) that produces a masterbatch and at least one second line (200B) that performs a final mixing process during a final pass of a multi-pass rubber mixing sequence. A mixing process produces a variety of rubber mixtures in a production line of the type disclosed.

A continuous process for making a pressure-sensitive adhesive is disclosed. A mixture comprising natural rubber having a Mooney viscosity of 85 to 100, a tackifier, a filler, and 0.1 to 5 wt. % of an added C.sub.12-C.sub.24 fatty acid based on the amount of mixture is masticated in a first section of a single- or twin-screw extruder. Mastication of the mixture continues in at least one subsequent extruder section in the presence of additional tackifier. The product is a homogeneous, reduced-viscosity pressure-sensitive adhesive. The minor proportion of added C.sub.12-C.sub.24 fatty acid aids mastication of the rubber and enables high throughput without addition of peptizers. Duct tapes made from the adhesives display improved adhesion to steel, better adhesion bond strength, and enhanced seven-day clean removability from even difficult substrates such as marble or ceramic tile.

Included is a homogeneous sheet, which excludes polyvinylchloride. The sheet includes a polyurethane, a synthetic rubber blend, and a filler. The synthetic rubber blend may include a pre-mix of a synthetic rubber and white oil.