Systems and methods for casting solid propellants include a mandrel for forming geometric features in a perforation of a propellant grain. In various embodiments, the mandrel includes a frangible portion that is removed from the propellant grain after the propellant grain has cured around the mandrel. A second portion of the mandrel may be left behind in the propellant grain. The mandrel may include a support structured disposed in the through hole of the mandrel. The support structure may include a plurality of longitudinal channels for directed exhaust gasses through the mandrel upon ignition of the propellant grain.

A pad for preventing tire skidding and a manufacturing method thereof, and is to provide a pad for preventing tire skidding and a manufacturing method thereof configured by a friction member formed by mixing a raw material rubber containing butadiene rubber and a functional additive; an adhesive layer coated with an adhesive on one side of the friction member so that the friction member is able to be adhered to a vehicle tire; and a mesh net embedded in the friction member or a mesh net connected to a piezoelectric element. The pad is provided with an adhesive layer coated with an adhesive and can be easily attached and used onto a vehicle tire, and is made of a large amount of butadiene rubber to increase the friction force against the ground.

A system (10) for butt-joining two or more rubber strips (B1, B2) selected in accordance with a predetermined rubber mixture recipe in order to feed at least one extruder with a complex strip of rubber material (B12) made from the butt joined rubber strips is disclosed. The system includes at least one conveyor that transports the rubber strips from an inlet (12) of the system to an outlet (14) of the butt-joining system; a frame (18) that operationally supports the conveyor to allow the continuous transport of the rubber strips and also to allow the simultaneous butt-joining of the rubber strips fed to the system; and a roller system (20) that butt-joins the rubber strips without penetration. The invention also relates to a process for butt-joining rubber strips that is performed by the system.

A system (10) for butt-joining two or more rubber strips (B1, B2) selected in accordance with a predetermined rubber mixture recipe in order to feed at least one extruder with a complex strip of rubber material (B12) made from the butt joined rubber strips is disclosed. The system includes at least one conveyor that transports the rubber strips from an inlet (12) of the system to an outlet (14) of the butt-joining system; a frame (18) that operationally supports the conveyor to allow the continuous transport of the rubber strips and also to allow the simultaneous butt-joining of the rubber strips fed to the system; and a roller system (20) that butt-joins the rubber strips without penetration. The invention also relates to a process for butt-joining rubber strips that is performed by the system.

The polyisoprene-containing latex composition of the present it comprises the following components (a) and (b): (a) zinc ethylphenyldithiocarbamate; and (b) 1-o-tolylbiguanide. Thus, a molded article of the latex composition has high tensile strength. Further, even after the latex composition is stored for a longer period of time than before, a decrease in the tensile strength of the obtained molded article is suppressed.

A latex composition includes a conjugated diene polymer latex and a silicone-based surfactant having a silicon atom content of 1.5 to 10 wt %. A dip-molded article is formed by dip molding the latex composition.

According to this procedure, these steps are made: a) immersing a shaped mold (4) in a dipping process in a liquid synthetic polyisoprene (IR) (synthetic latex), wherein the shaped mold (4) has previously been treated with coagulation agent (coagulants) or thermally treated, b) after the immersion, the synthetic polyisoprene layer is left on the shaped mold (4) and is freed from all salts with water, c) thereafter, the synthetic polyisoprene layer together with the shaped mold (4) is vulcanized in an oven, d) the synthetic polyisoprene layer is removed from the mold (4), e) the salts precipitated by the vulcanization on the synthetic polyisoprene molded body (11) are washed off with water and a chlorine-containing solution, f) the synthetic polyisoprene molded body (11) is halogenated to neutralize its pH and to increase its suppleness in contact with body skin with a halogenating solution, g) the synthetic polyisoprene molded body (11) is dried. The electro-protective gloves thus produced are much more comfortable to wear, provide better insulation, even with thinner wall thickness, and they are more durable.

An organic microgel system as support material for 3D printing of soft materials such as silicone and methods for manufacturing and using the organic microgel system are disclosed. In some embodiments, the organic microgel system comprises a plurality of microgel particles formed by blending a di-block copolymer and a tri-block copolymer in an organic solvent. The organic microgel system may allow high precision 3D printing of silicone objects with complex shapes.

The present disclosure is directed to additive manufacturing cartridges having an oxygen impermeable layer and to processes for producing cured polymeric products by additive manufacturing wherein the oxygen content during additive manufacturing is limited such as by use of the cartridge and/or by use of an inert gas.

A method for producing a glove includes a step of forming a dip-molded layer by dip-molding a latex composition containing a latex of a carboxyl group-containing conjugated diene rubber (A) that does not have an isoprene-derived monomer unit, and a metal compound (B) including a divalent or higher metal, and a step of irradiating the dip-molded layer with radiation.