Abstract: The present invention provides a blade-type tensioner system for a chain that can easily improve spring properties. A blade-type tensioner includes a blade shoe and a blade spring positioned on the back side of chain sliding surface of the blade shoe so as to impart tension to a chain through the blade shoe. The blade shoe is pivotably supported around a shoulder bolt inserted into a proximal end portion of the blade shoe, and a distal end portion of the blade shoe is slidably supported on a supporting face provided in the engine. Th distal end portion of the blade shoe contacts a flat, first supporting face at a point. When tension in the chain is increased, the distal end portion contacts a concave, second supporting face at a point which is continuous with the first supporting face.

Abstract: A method of continuously polymerizing a conjugated diene monomer and a vinyl aromatic hydrocarbon monomer in a hydrocarbon solvent by using an organolithium initiator, adding to the polymerization mixture a tin compound and again adding a tin compound after the polymerization mixture has been withdrawn from the polymerization vessel. The resulting diene polymers possess a significantly reduced Payne Effect and a substantial reduction (over 10%) in tan delta at 50° C. which results in tires having decreased hysteresis loss, excellent wear resistance and rolling resistance and good wet skid resistance.

Abstract: A method of producing a high-performance graft copolymer having both low-creep characteristics and damping properties is disclosed, which comprises:

Abstract: In one of several methods of producing polybutadiene or a butadiene-styrene copolymer with an organolithium initiator, an organotin compound such as tetraallyltin, tetrabenzyltin and tetraphenyltin is added to the polymerization system in a period of growth of the polymer chain between a time immediately after a start of the polymerization to a time before an end of the polymerization. In another of the methods, tin tetrachloride or tin dichloride is added at an earlier time after a start of the polymerization. A polymer comprising a considerable amount of high molecular weight polymer containing the chain having a tin-carbon linkage is formed. A rubber composition for tires comprises specified amounts of the polymer described above, natural rubber, carbon black and vulcanizing agents. The rubber composition has a small loss factor and excellent fracture properties.

Abstract: A method for preparing a polymer having low hysteresis loss value, good breaking properties and good processability with good productivity is provided by adding a tin compound during the propagation step of polymerization of a conjugated diene and/or an aromatic vinyl hydrocarbon. Polymers produced in accordance with this method have high molecular weight and star-shaped structures with branches having the same or different molecular weight.

Abstract: A method for preparing a polymer having low hysteresis loss value and good breaking properties using a novel lithium initiator compound for polymerization of a conjugated diene and/or an aromatic vinyl hydrocarbon. Polymers produced in accordance with this method contain tin in an amount more than usual, and can be manufactured with good productivity.