摘要:
Natural rubber containing viscosity stabilizers is treated under drying conditions to result in 10% or less of the difference of gel content and 85% or more of molecular weight retention between before and after drying, and methods for manufacturing natural rubber comprise treating under drying conditions to result in 10% or less of the difference of gel content and 85% or more of molecular weight retention between before and after drying. Natural rubber containing viscosity stabilizers is treated with a strainer, and methods for manufacturing natural rubber comprise treating with a strainer after compounding hydrazide stearate into the natural rubber. Gelation (storage hardening) is suppressed and a decrease in molecular weight is prevented.
摘要:
Natural rubber contains a viscosity stabilizer for the natural rubber, and the viscosity stabilizer includes a hydrazide compound of the following general formula, R--CONHNH.sub.2 wherein R is an alkyl group having 1 to 5 carbon atoms or a cycloalkyl group having 3 to 5 carbon atoms. As a result, gelation (storage hardening) is suppressed and a decrease in molecular weight is prevented.
摘要:
The present invention provides an oxidation catalyst for bleaching containing a component (a) which is an anion caused from a chelating agent having less than or equal to coordination position 5 and/or the chelating agent, and a component (b) which is a copper and/or manganese compound; and a binder compound (c); a hydrogen peroxide-based compound (d) which dissolves in water and generates hydrogen peroxide, the bleaching composition containing a granulated product or a molded product in which at least the component (b) and the component (c) are granulated or molded together. According to the invention, an oxidation catalyst that promotes the oxidation effect of hydrogen peroxide-based compounds with a trace amount of the composition, and has excellent effects of suppressing the decomposition of hydrogen peroxide-based compounds and suppressing coloration of the catalyst itself, and a bleaching composition containing the oxidation catalyst can be utilized.
摘要:
In a switching regulator, when a control switching signal received from outside is indicating PWM control, a second reference voltage generating circuit outputs, as a second reference voltage, a voltage that is lower than the minimum voltage of an output voltage range of an error amplifying circuit, so that output signals from a comparator are fixed at a high level. When a control switching signal received from outside is indicating VFM control, the second reference voltage generating circuit adjusts the second reference voltage according to the voltage difference between an input voltage and an output voltage, because the optimum second reference voltage varies according to the voltage difference between the input voltage and the output voltage.
摘要:
A polybutadiene rubber composition having an improved green strength is disclosed, which comprises a polybutadiene having a content of cis-1,4 bond of at least 70%, an average chain length of 1,4-bond of 110.about.450 and a molecular weight distribution represented by a ratio of weight-average molecular weight to number-average molecular weight of not less than 5.0.
摘要:
Rubber compositions having improved tensile strength, elongation and modulus of unvulcanized rubbers without deteriorating physical properties of vulcanized rubbers are prepared by utilizing synergistic effect of addition of a filler having high reinforcing property and alkadiene sulfones in given amounts to natural rubber and/or dienic synthetic rubbers.
摘要:
A racket string 10 of the present invention includes a synthetic fiber. The cross section is flattened by heating, compressing, and deforming the string after it has been formed, and an indentation is made in any part of the string. The flattened string is wound in a substantially non-twisted state. A method for producing the racket string includes heating the string at a temperature of Tg (° C.) or more and Tm −10 (° C.) or less, where Tg (° C.) represents a glass transition point and Tm (° C.) represents a melting point of a main synthetic fiber constituting the string, compressing and deforming the string between rollers 7a and 7b that are arranged with a predetermined clearance therebetween; and then cooling and winding up the string. In a racket strung with the racket string of the present invention, a principal surface of a hitting surface of the racket is formed of the flat surfaces of the string, and the strings include uneven portions due to torsion that are present partially and non-uniformly on the hitting surface of the racket. Thus, the present invention provides a racket string that can make full use of the features of the flat surface, a method for producing the racket string, and a racket strung with the racket string.
摘要:
A rubber composition having excellent fracture properties and cut growth resistance is disclosed, which consists of 10-95 parts by weight of polybutadiene having a content of cis-1,4 bond of at least 70% and an average chain length of 1,4-sequence of 110-450 and 90-5 parts by weight of at least one diene rubber.
摘要:
Organic micro-fiber reinforced rubber compositions having high elastic modulus, excellent crack growth resistance, impact cut resistance and rebound resilience and a small swell value are prepared by incorporating 10-100 parts by weight of carbon black, 3-30 parts by weight of organic micro-fibers based on 100 parts by weight of at least one rubber selected from a group consisting of natural rubber, synthetic polyisoprene rubber, butyl rubber, halogenated butyl rubber, polybutadiene rubber, styrene-butadiene copolymeric rubber, ethylene-propylene-diene ternary copolymeric rubber and acrylonitrile-butadiene copolymeric rubber, said micro-organic staple fibers being lower than 30.degree. C. or higher than 120.degree. C. in glass transition temperature of amorphous portion and higher than 160.degree. C. in melting point of crystal portion, and having an average length of the micro-fibers of 0.8-30 .mu.m, an average diameter of the micro-fibers of 0.02-0.8 .mu.m and a ratio of the average length of the micro-fibers to the average diameter of the micro-fibers of 8-400.
摘要:
This invention is intended to make a crucible feeder mechanism simple in configuration, to realize low cost and to increase the number of accommodated crucibles while making the crucible feeder mechanism small in size. In the crucible feeder mechanism, the crucibles are mounted on an inclined mount surface 311 in parallel and a tapered guide surface guides 312b the crucibles sliding down the mount surface 311 to a crucible moving mechanism 313 provided at an outlet port of a guide member. This crucible moving mechanism includes an accommodation concave portion 3131X accommodating one of the crucibles and provided on a circumferential surface portion 3131a of the crucible moving mechanism. The crucible moving mechanism rotates and moves between an accommodation position at which the accommodation concave portion receives the sliding-down crucible and a feed position at which the accommodation concave portion communicates with a crucible feed port 314 and drops the sliding-down crucible.