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Predecessor
Volume 36, Issue 1
Displaying 1-11 of 11 articles from this issue
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[in Japanese]1963 Volume 36 Issue 1 Pages 1
Published: 1963
Released on J-STAGE: April 16, 2008
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[in Japanese]1963 Volume 36 Issue 1 Pages 2
Published: 1963
Released on J-STAGE: April 16, 2008
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[in Japanese]1963 Volume 36 Issue 1 Pages 3
Published: 1963
Released on J-STAGE: April 16, 2008
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E. Tanaka, Y. Torigoe, T. Takemoto, H. Kinumaki, M. Oda1963 Volume 36 Issue 1 Pages 4-11
Published: 1963
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSIn studies on the physical properties and black dispersion of non-dispersant type black masterbatches and these dry mixed controls, the following results have been found.
1) Physical properties: Latex masterbatches have shown improvements from 10 to 20% in elongation, tensile strength, abrasion resistance, tear resistance and resistance to crack growth over dry mixed stocks, and slightly lower in 300% modulus. In hardness, impact resilience and permanent set, both were almost the same.
2) Black dispersion: In the dry mixed stock, the black dispersion was quite poor at 3min. Banbury mixing, and gradually improved its dispersion with increasing mixing time and attained to completeness at 30min. mixing. But in the latex masterbatch, the black dispersion attained to completeness at 3min. mixing, and it was almost equal to that of 30min. mixing.View full abstractDownload PDF (649K) -
Y. Takano, H. Kurumiya1963 Volume 36 Issue 1 Pages 11-21
Published: 1963
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSThis paper described the stress relaxation measurements as a quantitative method to evaluate the ozone deterioration of SBR vulcanizates containing several commercial antiozonants under static condition.
The effects of thickness and width of specimen, strain and ozone concentration on the stress relaxation of rubber due to ozone attack were studied. It was found that the rate of the stress relaxation of rubber band 1mm×10mm×60mm in ozone exposuring is linearly related to time t in the extent of 10%-100% elongation and shown by the following equation.
R=-Kt+b.
Where; R is the retention of stress, K is the rate constant of stress decay (the slope of the straight line) in ozone deterioration and b is a constant.
They depend on strain, ozone concentration and amounts of antiozonants.
It is thus possible to represent the ozone resistance of SBR vulcanizates by three parameters K, b and RH, which is time to 50% retention of stress. It seems that b means the existence of the induction period of first cracking, when the value of b is more than 100.
A new method of visual assessment of the deterioration of rubber due to ozone attack was also proposed and the good corelation between the stress relaxation assessment and the visual one was obtained. The stress relaxation method, however, provides no information on the cracking pattern and should be used in co-junction with visual evaluation.
The equipments used in this experiment are Toyorika OMS-2 ozone weather-meter for ozone chamber, Toyosei_??_i Relaxometer for measuring of the stress of rubber specimenout of the ozone chamber and specimen holdersespecially deviced to keep specimen definite elongation and measure their stress with the relaxometer.
In the analysis of the ozone concentra ion, the coulombmetry was used. The outdoor exposure test was briefly discussed with this stress elaxation method.View full abstractDownload PDF (955K) -
THE RE-EXAMINATION OF THE MECHANICAL STABILITY TESTING METHOD OF NATURAL RUBBER LATEXS. Kunisawa, M. Okikura, A. Taniguchi1963 Volume 36 Issue 1 Pages 22-25
Published: 1963
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSIn order to indicate the mechanical stability of natural rubber latex, the method of measuring the pass time of the first appearance of coagulated particle by rotating a definite size disc with high velocity in latex is widely used, and this method has been adopted in JIS or ASTM specifications.
This paper deals with the re-examination of the testing procedure, and the main results obtained are as follows: as to the method of judging of the end point, there is some definite time lag between ASTM method of measuring the first appearance time of clot and JIS method of measuring that of curd; the specification of weight % of coagulant in both methods in order to determine the end point has no foundation, so that this term is not suitable as a specification; and studies on the measuring temperature in detail were canied out.
From these results we found the necessity that the specification must be urgently co-ordinated or revised as the latex has the character of an international commodity.View full abstractDownload PDF (361K) -
EFFECT OF THE VOLATILE FATTY ACID NUMBER ON THE MECHANICAL STABILITY OF NATURAL RUBBER LATEXS. Kunisawa, M. Okikura, M. Hiramatsu1963 Volume 36 Issue 1 Pages 25-28
Published: 1963
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSVolatile fatty acids present in natural rubber latex are said to be directly affected on its mechanical stability. Several authors studied this relation mainly on fresh latex.
We measured the volatile fatty acid number (VFA No.) and mechanical stability of ammonia preserved latices of several kinds during the preservation of about 70 days, under constant conditions, and the correlation between VFA No. and mechanical stability was studied. About the latex of the same brand, it has been found that there is a primary correlation between both values, and VFA No. can be an important factor in evaluating the raw latex. But the absolute value of the VFA No. cannot be used in comparison between latices from different sources.View full abstractDownload PDF (338K) -
[in Japanese]1963 Volume 36 Issue 1 Pages 29-42
Published: 1963
Released on J-STAGE: April 16, 2008
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[in Japanese], [in Japanese]1963 Volume 36 Issue 1 Pages 43-67
Published: 1963
Released on J-STAGE: April 16, 2008
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[in Japanese]1963 Volume 36 Issue 1 Pages 68-74
Published: 1963
Released on J-STAGE: April 16, 2008
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[in Japanese]1963 Volume 36 Issue 1 Pages 75-76
Published: 1963
Released on J-STAGE: April 16, 2008
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