Nisshin Spinning Co., Ltd.

Nisshinbo Industries, Inc.

Japanese National Railways

Tatsuya Hongu

Toshio Suzuki

Yoshihiko Ogawa

Yoshihiko Sato

Fujio Ohishi

Takeshi Itoh

A vibration isolator composed of a low foam urethane elastomer having urethane bonds and a bulk density of 0.4-0.75 g/cm.sup.3 which is prepared from the starting foamable liquid of urethane elastomer composed substantially of

Vibration isolator

A resilient coat for a direct connection-type tie (Danchoku tie) which is composed of a concrete tie body and a microcellular polyurethane elastomer coating layer which adheres to and coats the lower portion of the tie body to form an integral body therewith, and said microcellular polyurethane elastomer having urethane bonds and a bulk density of 0.4-0.75 g/cm.sup.3 and being prepared from the starting foamable liquid of urethane elastomer composed substantially of (a) a polyether polyol having an average number of functional groups of 2.5-4.5 and a number average molecular weight of 2000-8500, (b) a vinyl monomer-grafted polyol having an average number of functional groups of 2.5-4.0, and the graft ratio of 4-20% by weight, (c) a liquid polybutadiene polyol having hydroxyl terminal group(s), an average number of functional groups of 2.0-3.0 and a number average molecular weight of 2000-7000, (d) an organic polyisocyanate, (e) a chain extender, (f) a blowing agent, and (g) a urethanation catalyst, at such ratios that the NCO index is within the range of 90-110, and the concentration of the chain extender, based on the total amount of the five components of (a), (b), (c), (d) and (e), being 0.3.times.10.sup.-3 to 1.5.times.10.sup.-3 mol/g.

Resilient coat for tie of direct-connection type track

A vibration isolator consisting essentially of a microcellular polyurethane elastomer having a bulk density of 0.3-0.9 g/cm.sup.3, said polyurethane elastomer obtained by reacting in the presence of water as the blowing agent (a) an organic polyisocyanate, (b) a polyether polyol having an average number of functional groups of 2.5-3.5 and a number average molecular weight of 4500-8500, and (c) a chain extender, in such a ratio that the NCO index is 90-110 and the concentration of the chain extender, based on the total weight of the three components (a), (b) and (c), is (0.4-2.0).times.10.sup.-3 equivalent/gram.

Microcellular polyurethane vibration isolator

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Tokyo, Japan

Tatsuya Hongu