FR2477956A1 - PROCESS FOR PREPARING RUBBER SOLUTIONS - Google Patents

Abstract

PROCESS FOR PREPARING RUBBER SOLUTIONS. THIS PROCESS CONSISTS OF GRINDING THE CONSTITUENTS OF THE RUBBER MIXTURE AND THE SOLVENT IN AN ATTRACTION DEVICE. RUBBER INDUSTRIES.

Description

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  The present invention relates to a method of preparation

  solutions of rubber from the constituents of a mixture of

Rubber and solvent.

  Such rubber solutions are used, for example, for the manufacture of coated fabrics, in particular for the manufacture of pneumatic channels and mattresses.

  pressurized air. For this purpose, the rubber solution is vulcanised

  after coating the fabric so as to obtain a

  its solid between the lagoon that forms and the fabric.

  So far, the preparation of rubber solutions has been carried out by dissolving in the solvent batch-shaped finished mixtures as well as batches in the form of granules or pieces by means of kneading or stirring devices. . If it was necessary to reduce the particle size, other processes of

  downstream work, for example in friction devices.

  Because of the relatively high temperatures that occur during this transformation, it was not possible to transform

very fast temperature.

  In addition, for the preparation of the batch or of the finished mixtures, expensive equipment was needed, such as, for example, rubber separators, heating chambers, batch mixers with accessories, mixers of finished mixtures with accessories, rolling cylinders, sieves, if necessary calenders, as well as preheating cylinders. Only few additives could be added to

  dissolution or by meeting two solutions.

  Finally, the particle size of the rubber solutions that could be obtained by the conventional method was still

  relatively high and was not inferior, as a rule

  at 50 microns. To improve the vulcanization, the density, the finish, and so on, generally in order to improve the finished product, efforts are made to obtain such a small particle size

  as possible; this could not be achieved by the

known.

  The invention aims at a process for preparing solutions

  rubber of the aforementioned type no longer presenting the disadvantages

mentioned above.

  In particular, the method makes it possible to obtain dimensions

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  extremely small particles in a relatively short time.

  According to the invention, the constituents and the

  solvent in an attrition apparatus.

  An attrition apparatus is an apparatus in which the grinding body and the grinding material, in this case the rubber compound and solvent components, are in a stationary vessel. The body that is used to grind and the amount of material to grind is rotated by a

  brewing device so as to impart cine-

  tick to the body used for grinding; because of friction and abrasion shocks, a very good distribution is obtained

  uniform particle size.

  In addition, in such an attrition apparatus, there is generally a pumped system so that one can maintain

  charge in closed circuit during grinding.

  In case of need, we can also control the temperature

of the material to be grinded.

  It has now been found that the use of such a device

  attrition gives particle sizes of the order of 10 microns, whereas the time required for this purpose is

  smaller than in the known process.

  We have the slightest expense in equipment for the preparation

  of the rubber solution when the constituents

  still unmixed rubber mixture and the

  solvent are ground directly into the attrition apparatus.

  The aforementioned equipments necessary for the preparation of the finished mixture or batch are no longer so, so that - = i1- Ie procedure relative to

  to that of the known process. And yet we can obtain granules

  above-mentioned lometries of about 10 microns in one

only stage of work.

  Alternatively, it is also possible to grind in the attrition apparatus so-called finished mixtures or batches in the form of

  pieces or granules, as well as the vulcanization accelerator

  and the solvent. Thus, in comparison with the known method, a significant simplification is obtained when it is necessary to obtain relatively small particle sizes, namely

  particles having a size of about 50 microns.

  In addition, it is also possible to convert, thanks to the process according to the invention, temperature-sensitive and highly accelerated rubber mixtures, since temperatures which occur during grinding in an attrition apparatus are relatively low and do not provoke. not a package of

the reaction of the finished mixture.

  Finally, it is possible, if need be, to add additives without difficulty by adding the material to be milled in

  the apparatus of attrition at a suitable moment.

  Although in principle it can be used for

  of attrition of the usual grinding bodies, for example flint or metal balls, preference is given to

soapstone balls.

  The invention is illustrated by two embodiments.

  In a first embodiment, the usual constituents of a rubber mixture, the vulcanization accelerator and the solvent are placed at the same time, or one after the other, in an attrition apparatus, and grind to obtain the desired size of about 10 microns. If needed,

  if it is necessary, we can also add the usual additives.

  In the second embodiment, simultaneous positioning is

  one after the other, in the attrition apparatus,

  granules of a batch or pieces, the vulcanization accelerator

  and the solvent and is comminuted by grinding to the desired particle size of about 10 microns. There too

  if necessary add up additives.

  According to the experience gained so far, all the usual materials for the preparation of rubber solutions could be used. Thus, good results are obtained with both natural rubber and synthetic rubber, for example butyl rubber, or

  polymers of chloroprene. Even when using soil

  classics, for example toluene or benzene, it does not

presents no difficulties.

Claims (5)

  1. A process for preparing rubber solutions from the constituents of a rubber mixture and a   solvent, characterized in that it consists in grinding the constituents   killing of the rubber mixture and the solvent in an attrition apparatus. 2. Method according to claim 1, characterized in that it consists in grinding a finished mixture and the solvent in the attrition apparatus.   3. Method according to claim 1 or 2, characterized in that it consists in adding the vulcanization accelerator during grinding.   4. Method according to one of claims 1 to 3,   characterized in that it consists in using as a body of grinding spheres of soapstone.   5. Method according to one of claims 1 to 4,   characterized in that it consists in breaking up by grinding the constituents of the rubber mixture until obtaining a   particle size of about 10 microns.