DE1900269A1 - Process for processing visco-elastic materials - Google Patents

Description

VICKBRS LIMITED,
Vickers House,
Millbank Tower, Millbank,
London SW 1 / England

Patent application

Process for processing viscous-elastic materials

The invention relates to a method for processing viscous-elastic material, in particular, however not exclusive, process for processing rubber.

The manufacture of tires or other objects made of rubber takes place, for. Currently in the following work stages:

1st main mixing stage: rubber is mixed and kneaded together with carbon black or other fillers and with Oil or an equivalent medium, in order to form a so-called "master batch", which also contains pigments and may contain other additives. This stage of work is generally followed by in internal mixers Grinds, extruders or mixer-extruders carried out to a "master-batch" in the form of surfaces, strips or To get tablets. This "master batch" is cooled and either stored or processed immediately «

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2nd final mixing stage: This takes place in order to Auxiliaries such as sulfur, generally xn finer Powder form, as well as accelerators and the like additives to disperse. These cause "or influence the speed the vulcanization or crosslinking of the rubber. The final mix can be done on the same machines as for the "master-batch" or especially in mills or mixing extruders carried out v / earth. The final mix also results in areas, strips or tablets and is immediate cooled before it leaves the mixing device generally known as the "grinding chamber".

3. Deformation stage: It takes place by pressing, calendering, injection molding or composite processes such as Tire construction.

4. Vulcanization: This is usually carried out with a controlled supply of heat with or without pressure on a continuous basis or on a discontinuous basis.

In these different ways of working, different conditions in the individual stages play a major role. You are responsible for dividing the process into the stages mentioned. With regard to cooling after the Endvermischung Endverformen also brings mixing as a by-product of the effort to plasticize with it, the material that is to be heated and uniformly to edit.

The main work consists in the distribution of the fillers, which are generally in powder form, on the one hand, and the generally oily extenders and auxiliaries or other additives (generally powders) in the rubber structure, which often do not exceed certain limits with regard to the requirements of the end product may be broken out. in the

In contrast to these 'distribution conditions is the Heat sensitivity of the vulcanization process, which must be controlled until after the final deformation. These opposing conditions cause the different stages of the main mixing ("master-batch") and the Final mixing, with both cooling being directly connected. The main mix generally proceeds at a much higher temperature than the final mixture (if the excipients are added first) and as the following deformation before vulcanization.

Furthermore, difficulties arise in the different stages because of the dosage of the different ones to be mixed Substances in the machines. This is another reason the main mixer stage and final mixer stage are separate from each other and to limit this to the "grinding chamber". The product from the grinding chamber (cooled Final mix) is formed elsewhere after a quality control of the dosage of the ingredients has been carried out. It should be pointed out that there may be difficulties with the dosage, a) with regard to the Ability of the rubber to produce the necessary quantities of fine powders (e.g. Soot) to absorb, b) in terms of the ability of the rubber compounds to absorb the required amounts of oil or other extenders in any case to absorb without fouling the mixture. These difficulties arise mainly in the main mixing stage and have to develop devices for an ear proportioning and dosing guided, which are suitable for different amounts of additives in different stages of the mixing process according to the predetermined one Admit program, continue to develop extremely strong constructions and drives with holier Mlsckerkraft.

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Another type of dosage difficulty occurs at the final mixing stage, "at the auxiliary s st off β and others Additives are generally added in only a few percent by weight of the main mixture in the form of fine powders will. A degree of macrodispersion (achieved by less intensive mixing) of the excipients in the tablets, the is sufficient to get the best results except with an effective mixing extruder is difficult with conventional premixing methods can be used to achieve the required microdispersion even when a mixing extruder is used (achieved by intensive mixing of the material) of the auxiliary powder in the main mixture.

In contrast, the invention relates to a method for incorporating solid particles in a viscous-elastic Material which is characterized in that the material is tabletted that the tabletted Material an ingredient is added to the surfaces of the tablets adhering to the solid particles to be incorporated to make that the solid particles be dispersed over the adhered surfaces of the tablets so that they adhere firmly and that the Tablets with the adhering solid particles are processed so that they are in the viscous-elastic material are incorporated.

Another object of the invention is a method of incorporating solid particles into a viscous-elastic Material which, after tabletting, consists of tablets, the surfaces of which are adhered by the solid particles bind, which is characterized in that the viscous-elastic material is tabletted that from the Components of the mixture for which the viscous-elastic material is to be used, a solid in the form fine particles are selected so that the solid particles disperse over the adhesive surfaces of the tablets.

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be yawed, and that the tablets are processed together with the adhering solid particles to the Incorporate pesticide into the viscous-elastic material.

For a better understanding of the nature of the method according to the invention, individual exemplary embodiments are described below explained in more detail.

1. In the case of the final mixing of the main mixture ("master-batoh") in tablet form, it is made from the original master-batoh-recipe a small proportion of the oil or another Retain anti-pollution. This oil is added to a mixer in the cooled master batch trays are weighed so that the oil is distributed over the surface of the tablets, the surfaces of the tablets get sticky that way. Then the auxiliary powder, preferably in premixed form, added and mixed. In this way, the solid particles in the form of the auxiliaries are spread out evenly and evenly bonded to the moist, sticky surface of the tablets. With this method there is the premix of essentially dry tablets with very little tendency to cake to have. The mixture is in the exact proportions of its constituents and in the degree of macro-misalignment held for further treatment.

To facilitate premixing, the oil or other extenders preheated and, if desired, sprayed onto the surrounding mass of the tablets in the premixer will. The tablets are processed for a sufficient time to allow the wetting agent to spread evenly to ensure on the tablet gate surface. Similarly, can the excipient powder is applied to the sticky tablets. Such measures reduce the premixing time.

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2, According to another example, gum is tabletted, Oil or other excipients distributed on the tablets in such a way that they become sticky and solid particles added in the form of carbon black or other fillers and until essentially dry tablets are formed, which are suitable for a "master batch", mixed.

3. According to a third example, two types of synthetic rubber are in a relatively sticky state together with accelerator powder and part of a filler, d. H. together with solid particles of the ingredients of the mixture for which the gum is to be used, tabletted to essentially not

^ to form sticky tablets. Instead of two types synthetic Rubber, synthetic and natural rubber, or natural rubber alone, can be processed. After passing through an extruder mixer, a band of plasticized rubber mixture is pressed out and (with or without intermediate cooling and tabletting) into a second extruder mixer together with further oil and Entered filler. This work step can be repeated for mixtures that require a greater degree of oil extension will. No internal mixer is provided for this process. The extruder mixers in different places are brewed, are the required throughput in terms of size adapted that for the first extruder mixer

j) small, e.g. B. $ 20, the final push, can be.

The size of the tablets is used to process the rubber of the starting product largely the amount and Particle size of the additives adapted. For example, if If a large amount of powder is to be added, the tablets are kept as small as possible in order to be as large as possible Form surface. On the other hand, the tablets can be used for the final mixture, in which generally only

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a small amount, e.g. 5 #, of fine powder added should be quite big

The tablets used in the process according to the invention can have any shape ".

Each of the embodiments described above results in a fairly high and consistent standard a macro-dispersion of the ingredients before they are put into an intensive or micro-distribution mixer, preferably a mixer-extruder. In addition, such a macro-dispersion is achieved on the one hand by machine with only a small input energy per batch unit, z. B. with a mixing drum or ribbon mixer or the like. On the other hand, by proportioning the Constituents at every stage and not necessarily in the With a view to the fact that the exact proportions in a single premix or a single intensive Mixture are observed.

Although only rubber is used in the embodiments described, other viscous-elastic ones can of course also be used Substances are processed in essentially the same way; d. H. Solid particles can be in the viscous-elastic material by tableting the material, adding an ingredient to hold the solid particles in place on the tablets, distributing the solid particles on the surface of the tablets, and processing of the tablets are incorporated. Any ingredient that is added to the surface adheres the solid particles to make acts as an extender. On the other hand there are different viscous-elastic materials, in the case of tabletting, the surfaces of the tablets adherent to dl & particulate matter, in which case the admitted; Solid is chosen from the ingredients of the mixture in which the coated tablets are used should be.

9 0 9 8 3.1 / 1 2 10

If the solids to be added are not already available in partial form, they are initially taken accordingly prepared into solid particles.

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Claims (7)

Claims 1. A method for incorporating solid particles into a viscous-elastic material, characterized in that that the visco-elastic material is tabletted, that a component is added to the tabletted material is to make the surfaces of the tablets adherent to the solid particles to be incorporated that the Solid particles are dispersed over the tablet surfaces in such a way that they adhere to them and that the Tablets with the adhering solid are processed to convert the solid into the viscous-elastic material to incorporate. 2. The method according to claim 1, characterized in that that the viscous-elastic material is a masterbatch rubber in which the component is made up of oil or a other extender and in which the solid particles contain auxiliary powder. 3. The method according to claim 2, characterized in that the oil or another extender to one small portion of the initial master batch is withheld. 4. The method according to claim 2 or 3, characterized in that the oil or another extender is heated. 5. The method according to claim 4 »characterized in that that the heated oil or other diluent is sprayed onto the tablets, causing the tablets to roll will. 6. The method according to claim 2-5 »characterized in that that the excipient powder sprinkled onto the tablets will. 909831/1210 7. The method according to claim 1, characterized in that the viscous-elastic material made of rubber as Part of a master hatch is that the added ingredient is oil or another extender and that the pesticide particles are made of soot or some other Consist of filler. The patent attorney 909831/1210