SU1862A1 - Method and device for producing porous sheets or plates of rubber, gutta-percha, balata, and the like. from milk juice - Google Patents

Description

Nowadays, raw rubber is obtained by coagulating milk juice. In order to obtain technically pure rubber, the product obtained by rolling is washed and rolled. With this method, however, the product comes out to be extremely non-uniform, and its quality is dependent on both the thoroughness of the washing, and the longer or longer the rubber is processed by the rollers, as well as on the preservation of the initial colloidal structure. The heterogeneity of the properties of raw rubber, obtained with the same treatment from the same plants and from the same area, causes difficulties in operation, due to which Hopkinson proposed a method for producing rubber by spraying milk juice in hot air, then drying and then pressing into plates or bars. With this method, the colloidal structure of the rubber is retained, but to obtain a product free of

from impurities, it is necessary to further wash it. Attempts to obtain pure rubber using the coagulation of milk juice in a centrifugal apparatus are also known, the action of which simultaneously had to be carried out and cleaning, but in practice this method proved uneconomical. On the other hand, they tried to obtain rubber from milk juice by precipitation using an electric current, but this method also gives raw material that requires subsequent washing, since the sediment obtained from milk juice contains much of the gummy impurities of the latter, which show a negative charge and electrophoresis move in the same direction as a rubber particle.

The present invention relates to a method for directly producing pure raw rubber in milk juice sheets without prior machining of the coagulated product and while maintaining its original structure. For

This milk juice is freed from impurities by centrifugal processing, which allows the juice of the highest concentration to be continuously mixed during processing, after which the rubber is subjected to electrophoresis, and it is precipitated from the purified and enriched juice on the anode as a spongy sheet separated from the anode upon leaving out of the bath. It is proposed to add some reagent that prevents clotting, for example, about 0.5% ammonia, to milk juice before processing in a centrofuge or before electrophoresis.

By using a centrifugal apparatus, driving it at a suitable speed, and also selecting the thickness of the separated concentrated layer in an appropriate way, all rubber contained in milk juice can be converted into a concentrate containing over 60% pure dry rubber, and serous coming out of the centrifugal apparatus process the liquid in the same way, repeating centrifuging several times. Thus, it is possible to turn all rubber contained in milk juice into a stable concentrate containing about 50 - 60% dry rubber and technically free from impurities.

Further, the author found that with this method of concentrating and purifying milk juice, it is best to preserve the transparent color of the rubber. For this purpose, the dairy juice is processed with organic dyes, the ultramicrons of which, in the state of hydrosol, have a negative charge. Such dyes are partly absorbed by particles 1: acacia, did not cause it to coagulate, and enter into concentrate, meanwhile how unabsorbed parts of them remain in the serous fluid, or are deposited in the sediment.

From such purified and, if desired, colored rubber milk juice, rubber is precipitated by electrophoresis on the anode. During the electrophoretic deposition of a rubber, the dyes absorbed by its particles enter with it the sediment, which takes the form of a rubber sheet and a completely uniform color. Like these dyes, a whole series of well-known additional reagents can be introduced into the milk juice, which can be preliminarily brought into a colloidal state. In the case of the use of additional reagents, the ultramicrons of which, being in a sprayed state in a liquid, have a negative charge, cataphoretic deposition gives a homogeneous rubber mixture.

The drawing shows apparatuses for the direct production of vigorous sheets from a centrifuged-enriched milk juice, which can be dyed or in which additional materials can be added. FIG. 1 shows a schematic longitudinal section of a drum attachment; FIG. 2 is a longitudinal section of the device with an endless belt; FIG. 3 shows the same section of the device with an endless band, which at the same time forms a reservoir for milk juice.

The purified concentrated milk juice (c) is poured into the tank (b), in which the rotating metal drum is placed (a) (Fig. 1). The latter is connected to the positive pole of the current source (d) and serves as the anode. (K) -Cong electrodes connected to the negative pole of the current source. The drum (s) rotates in the direction of the arrow. Under the influence of the cataphoretic action of the electric field, the rubber particles move to the anode (f), on which, as a result of the release of acid ions and oxygen bubbles on it, the rubber is deposited in the form of spongy, but coherent deposition. The deposited rubber layer is separated from the part of the drum that protrudes from the bath in the form of a continuous spongy or spongy sheet (e) that can be easily released from its attachment, unfolded juice, and dried. The resulting vascular sheet is clean, does not require further processing, as a result of which its original colloidal structure is not disturbed. By electrophoresis, it is possible to collect all rubber contained in milk juice. without detriment to the quality of the product, but since the rate of separation decreases with a decrease in concentration, it is useful to enrich the weakened bath by centrifugation or electro-osmosis.

The material for the anode needs to take such a conductor that is least eaten away by liberating acid and oxygen ions, for example, amalgamated zinc.

In the apparatus shown in FIG. 2. The anode is a metallic tape or metallic cloth (a), in which the horizontal part (a), of the greatest possible length, is located below the level of the bath; at the bottom of the tank (1), the cathode (k) is located under the part faj. Excess juice is removed from the rubber sludge on the belt as it leaves the bath between the rollers (I), (I), after which the belt passes over the tank (f /) and sprayed with nozzles (k). and then dried over the drying table (/). The dried sheet is separated from the tape (a) and folded. Deposition of the rubber nozzle strip can be carried out both on one side of the tape (p) and on both.

FIG. 3 shows a device in which the tape (a) forms a loop (nj) j inside which a cylindrical rotating carbon cathode (K) interferes, at the ends of which fr disks are placed) of a nonconductor, mainly rubber, possibly tightly pressed to the edges of the tape (a ,,). An enriched milk juice is poured into the reservoir thus formed, in the form of a trough, and the latter is collected in a trough (t) to prevent leakage of the juice.

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1. A method of obtaining porous sheets or plates of rubber, gutta-percha, balata, etc. from milk juice, which differs in that milk juice, with the addition of a small amount of any stabilizer (for example, ammonia), is enriched by repeated centrifugation to 50 - 60% of the dry matter content and then subjected to electrophoresis.

2. At the method indicated in paragraph 1, the introduction into the milk juice before centrifuging organic dyestuffs or other well-known ingredients of rubber mass, for example, sulfur, previously converted to a colloidal state, whose ultra-microns have a negative charge.

3. The electrophoresis apparatus according to the above. 1 and 2 for a method that differs in application m. As an anode, a rotating drum (a) (FIG. 1) or an endless belt (a) from any current conductor (FIG. 2), immersed partly in the vessel (b) c enriched milk juice, with COAL or other cathodes located opposite the submerged part of the anodes.

4. The form of execution of the apparatus indicated in clause 3, characterized in that. that the cathode (1) (Fig. 3) has a cylindrical shape and carries at its ends a non-conductor disk (p) serving to clamp the anode (a.-) tape between them, guided by the rollers in the form of a loop under cathode, so that it forms together with the disks (p) a trough for placing milk juice.

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