Temperature dependence of mechanical data was investigated for SBR samples of various molecular weights using a Mooney Viscometer. Among five time-independent constants involved in Eqs. (1), (2) and (3) in the text, it was found that τ, AL_∞, and YL (=ML_∞-XL) have the same temperature dependence as that of Arrhenius type with an apparent heat of activation of 5kcal/mol, whereas ML₀ and XL do not change their values with temperature within the range examined.
Effects of extender oil in oil-extended SBR samples were analysed for the mechanical data obtained by a Mooney Viscometer. The results show that the constants, except for τ, are all subjected to the dilution effect of oil and that the plasticizing effect of oil appears to be the same for τ, YL, and AL_∞. The plasticizing effect on those constants can be approximately expressed by a single exponential function of the volume fraction of the oil, v₁. Thus for τ,
τ(v₁=v₁)_??_(v₁=0)=e^-v₁/a,
where a is a constant independent of v₁.

View full abstract

Mechanical data of filler masterbatch of SBR were obtained by using a Mooney Viscometer at a fixed temperature of 100°C. Carbon black, calcium carbonate and soft clay were used as fillers. The data obtained were successfully analysed in terms of Eqs. (2), (3) and (4) in the text. The constant, τ involved in Eq. (2) was found to be little affected by the presence of fillers in all cases. The values of YL (=ML_∞-XL), XL and AL_∞ increase with filler content and the dependence of those constants on filler content can be well described by the treatment introduced by Guth and Gold. Thus,
YL(V₁=V₁)/YL(V₁=0)=1+2.5V₁+14.1V₁²,
XL(V₁=V₁)/XL(V₁=0)=AL_∞(V₁=V₁)/AL_∞(V₁=0)=Ω(1+2.5V₁+14.1V₁²).
Here V₁ represents the volume fraction of filler and Ω is a constant slightly less than unity. It appears that the value of Ω remains constant within the range of V₁ examined (0.05-0.30) for each system, but the larger the particle size of the filler, the smaller it becomes.

View full abstract

When we transport rocks or coals by means of conveyor belts, we usually drop them onto a running belt, and transport them. In this case, the conveyor belt receives shocks repeatedly from rocks or coals falling down. If the shock exceeds a certain level, it causes the conveyor belt breaking dowa. Design of conveyor belt world be substantially convenient if the stress and elongation of the belt at the time of receiving shocks is clearly found out.
For this purpose, we took photographs to examine the relation of partial elongation of the belt, the number of plies, property of the belt cover, and edge angle of falling materials.

View full abstract

In these days the great power is transmitted from one shaft to another by means of a number of V belts. Sometimes twenty or thirty belts are used to transmit the power. When we looked at them, we wondered if each belt transmits the equal amount of power or not.
This paper deals with this problem, Fig. 1 and 2 show the apparatus used. A is a motor, and by means of the two belts, power is transmitted from A to shaft E. B and C are sheaves on which the belts are mounted. The diameter of both sheaves is 4 inches. Shaft E can slide on guide shown by dotted line in Fig. 1. H is a pulley to which the load is applied by these ropes. The initial tension is applied to the belts. Prony brake is set on shaft F. By this brake, we can put the load to the belts. The amount of load is calibrated. Then we pasted two phosphoric bronze plates on each belt at a certain distance. Fig. 3 shows phosphoric bronze plate pasted on the belt.
When the belts are running, these plates come in contact with the terminal of electro magnetic oscillograph. The circuit of oscillograph is closed, and the peaks are marked on the paper of oscillograph as shown in Fig. 4. By calculating the times between peaks, we estimate the length between two phosphoric bronze plates. From the distance between the two bronze plates, we can find the ratio of power transmitted to one belt, in assuming that the elongation of belt is proportional to the power transmitted.
Through these experiments, we can find that, when we transmit the power by several belts from one shaft to another, each belt does not generally transmit the equal amount of power.

View full abstract

This paper deals with temperature rise of belts when they are running. The temperature rise of running belts considered to be caused by the following three reasons.
(1) repeated bending of belts caused by sheaves when they run into them.
(2) change of tension of belts when they come into tension side and sluck side alternatively.
(3) friction between belts and sheaves.
Fig. 1 and 2 show the apparatus used. A is a motor, and by means of two belts power is transmitted from A to shaft E. B and C are sheaves on which belts tested are mounted. The diameter of both sheaves is 4 inches. Shaft E can slide on guide shown by dotted line in Fig. 1. H are pulleys on which loads are mounted by these ropes. The initial tensions are applied on belts tested. Prony brake is set on shaft F. By this brake, we can put load on belts. The amount of load is calibrated.
We tested three kinds of B type V belts. They are 55 ins. and 72 ins. length with normal thickness, and 55 ins. length with thin thickness.
According to this experiment, we can find that repeated bending of belts (1) and change of tension of belts (2) have as much effects as friction between belts and sheaves on the temperature rise of belts.

View full abstract

A triazine type compound and thiadiazoles prepared in Part I and mixed type compounds of a mercapto-thiadiazolecoupled with a moiety of the commercial accelerators and thiolsulfonate type compounds prepared in Part II were utilized as vulcanization accelerator for natural rubber. By using each one of them as accelerator, and compounding Hakuenka or carbon black as well as the other ingredients, vulcanizates were obtained under a given condition and their physical properties were compared with those of vulcanizates with commercial accelerator, D, M or TT. Accelerated aging test of vulcanizates with new accelerators was also carried out. On the basis of the results obtained here new accelerators were found to have comparable efficiency to the commercial accelerators.

View full abstract

Rheological properties of rigid vinyl sheets prepared according to several general formulae were examined within the range of manufacturing temperature. In consequence, it was revealed that the representative equation for non-Newtonian fluid
D=1/η^*τ_n^w
was applied for rigid vinyl sheets, where
η^*: coefficient of viscosity
τ_w: shearing stress along the wall
n: non-Newtonian constant.
As to the rigid vinyl sheets, it was shown that the value of n is greater than 2 even at the temperature higher than 160°C.
Applying Poiseville′s equation, apparent viscosity η^* corresponding to various τ_w was calculated, then η₀ was obtained by extrapolating η^* to τ_w=0. The relation between log η₀ and 1/T was shown by linear diagram, where T was absolute temperature. From this relation, free energy change associated with the activation of flow was calculated.
The above mentioned results mean that higher temperature and higher pressure should be necessary for manufacturing of rigid vinyl sheets as compared with other plastics.

View full abstract

Study was made on separating and confirming various antioxidants rapidly by the application of electrophoresis.
The majority of the antioxidants are difficultly soluble in water and do not ionize as they are but when coupled with diazonium salt of sulfanilic acid and made into azo-dyes, each will show its characteristic color, depending on the kind of antioxidants and at the same time, will become ionized. It will become possible to detect the different kinds of antioxidants when electrophoresis is carried on with these azo-dyes. That is, paper electrophoresis was carried on by coupling acetic acid solution of amine antioxidants with diazonium salt dissolved in acetic acid using acidic electrolyte (acetic acid-isopropanol-water mixture). Also, phenolic antioxidants dissolved in ethanolic sodium hydroxide solution was coupled with diazonium salt and then electrophoresis carried on with aqueous borax solution or methanolic solution or ethanolic solution of borax as electrolyte. The various antioxidants were easily detected by observing the movement of substances on the filter paper and by the characteristic coloring after electric current was passed for an appropriate time.

View full abstract

Study was made of the method of separation and confirmation of antioxidants present in vulcanizates by the application of the detection method for antioxidants by the paper electrophoresis method explained in the previous report.
Finely-cut vulcanizate samples were extracted with acetone, acetone distilled off from the extraction solution and then dissolved with acetic acid in case it contained amine antioxidant and in ethanolic sodium hydroxide solution in case it contained phenolic antioxidants. There were coupled with p-diazobenzene sulphonic acid to produce azo-dyes, after which, paper electrophoresis was carried on. After passing electric current for an appropriate time, the coloring on the filter paper and the distance travelled were observed and in case of amine antioxidants, these can be easily separated not only when they are mixed in vulcanizates independently but even when two or three kinds are present together in a mixed state. In case of phenolic antioxidants, there are cases in which it was not possible to separate them when two or three kinds were present together in a mixed state. Interference by accelerators or other compounding agents was not observer in the above-mentioned analytical method with the exception when aldehyde amine accelerators were used.

View full abstract