EP-4735225-A1 - METHOD AND SYSTEM FOR PREPARING A RUBBER MIXTURE

Abstract

The invention relates to a method for preparing a rubber mixture (3), comprising the steps of: mixing the rubber mixture (3) in a first rubber mixer; processing the rubber mixture into a defined shape (15) in a shaping machine (1a); cooling the defined shape (15) of the rubber mixture (3) in a cooling device (5); cutting off one or more pieces (16) from the defined shape (15) of the rubber mixture (3); weighing a defined mass (17) of the one or more pieces (16) of the rubber mixture (3); pressing the defined mass (17) of the rubber mixture into a bale (13); and feeding the bale (13) into a second rubber mixer. The invention furthermore relates to a system for carrying out the method.

Inventors

• HESSE, MARKUS
• Bommer, Tim
• WÄSCHENBACH, Pascal

Assignees

• Harburg-Freudenberger Maschinenbau GmbH

Dates

Publication Date

20260506

Application Date

20240628

Claims (1)

1. P2023,0616 WO N June 28, 2024 - 15 - Claims 1. Method for preparing a rubber mixture (3), comprising the steps of: - mixing the rubber mixture (3) in a first rubber mixer (1), - processing the rubber mixture (3) in a shaping machine (1a) to give a defined shape (15), - cooling the defined shape (15) of the rubber mixture (3) in a cooling device (5), - cutting off one or more pieces (16) from the defined shape (15) of the rubber mixture (3), - weighing a defined mass (17) of the one or more pieces (16) of the rubber mixture (3), - pressing the defined mass (17) into a bale (13), - adding the bale (13) to a second rubber mixer (14). 2. Method according to claim 1, wherein the rubber mixture (3) is discharged from the forming machine (1a) in the form of strips. 3. Method according to claim 2, wherein the strips are cut into sections of a defined length. 4. Method according to one of the preceding claims, wherein the defined mass (17) contains several pieces (16). 5. Method according to one of claims 1 to 3, wherein the defined mass (17) contains only one piece (16). P2023,0616 WO N June 28, 2024 - 16 - 6. Method according to one of the preceding claims, in which the rubber mixture (3) is cut without intermediate storage and without manual handling after passing through the cooling device (5). 7. Method according to one of the preceding claims, in which during weighing further pieces (16) are cut off and weighed until the defined mass (17) is reached. 8. Method according to one of the preceding claims, in which shortly before the defined mass (17) is reached, the size of the pieces (16) is reduced during cutting. 9. Method according to one of the preceding claims, wherein the rubber mixture (3) is immersed in a water bath for cooling and then air-dried. 10. Method according to one of the preceding claims, wherein the bale (13) is free of anti-stick reagents when added to the second rubber mixer (14). 11. Method according to one of the preceding claims, wherein the entire process is carried out automatically without manual handling of the rubber mixture. 12. Arrangement for preparing a rubber mixture (3) according to the method of one of the preceding claims, comprising a first rubber mixer (1), a shaping machine (1a), a cooling device (5), a cutting device (8), a scale (9), a baling press (11), a second rubber mixer (14) and transport devices (2, 12) between the individual P2023,0616 WO N June 28, 2024 - 17 - Devices, wherein said devices are designed to be passed through by a rubber mixture (3) in the order mentioned.

Description

P2023,0616 WO N June 28, 2024 - 1 - Description Method and arrangement for preparing a rubber mixture The present invention relates to a method and an arrangement for preparing rubber mixtures. In particular, the use of anti-adhesive agents in so-called batch-off systems during rubber processing represents a significant problem, since anti-adhesive agents are associated with a large number of disadvantages and risks. Such anti-adhesive agents are, for example, a dispersion of zinc stearate or magnesium stearate. These challenges include, among other things, the precise monitoring of the anti-adhesive agent concentration, which requires complex measuring technology and maintenance, as well as the contamination of the systems by dripping solution, which leads to deposits in the systems. The use of anti-adhesive agents can also impair product quality, as it is an unwanted foreign substance that is not part of the rubber formulation. In addition, uneven distribution when applying the anti-adhesive agent can lead to large layer thicknesses and cause feeding problems in subsequent mixing processes, as, for example, a lubricating film on the rotors and the material strips hinders feeding into the mixing chambers. P2023,0616 WO N June 28, 2024 - 2 - In addition, there is a risk of the formation of harmful bacteria and foam formation in the anti-adhesion film, which requires the use of additional chemicals. Another problem is the integration of strip cutters into the mixing process, since picking up a rubber strip and placing the strip on a conveyor belt of the strip cutter usually require manual processes. Both the position and the shape of the strip are usually not defined, which makes automation of the process difficult. One object of the present invention is to provide an improved preparation method and a corresponding arrangement. The present invention relates in particular to a method for preparing a rubber mixture. The method comprises at least the following steps: - mixing the rubber mixture in a first rubber mixer, - processing the rubber mixture in a shaping machine to a defined shape, - cooling the defined shape of the rubber mixture in a cooling device, - cutting off one or more pieces from the defined shape of the rubber mixture, - weighing a defined mass of the one or more pieces of the rubber mixture, - pressing the defined mass of the rubber mixture into a bale, - adding the bale to a second rubber mixer. P2023,0616 WO N June 28, 2024 - 3 - The process can be repeated several times, for example between a second and third or between a third and fourth etc. rubber mixer. The process can be carried out repeatedly with the same arrangement or system or with different arrangements and systems. Repeated mixing is particularly necessary to improve the mixing quality or to provide different mixing and ambient conditions for different mixing processes. In particular, for example, vulcanization-inducing chemicals are often only added during the second or third mixing run. In the first step, the rubber mixture is transferred from the first rubber mixer to a shaping machine, such as an extruder or a rolling mill. This can be a sub-machine of the rubber mixer, which is arranged below the rubber mixer so that the rubber mixture can be ejected from the mixing chamber into the shaping machine. For example, the rubber mixture is brought into a suitable, manageable form in the shaping machine for removal and further processing. Preferably, the rubber mixture is removed from the molding machine in the form of strips. “Strips” means that the rubber mixture has a strip shape, i.e. the length of the surface of the molded body formed preferably significantly exceeds the width of the surface and a height perpendicular to the width and length of the strip is significantly less than the surface dimensions of the strip. Such strips P2023,0616 WO N June 28, 2024 - 4 - are also called skins in rubber processing. Pieces, especially sections of a defined length, can easily be cut off from a strip and easily processed further. The strips with a comparatively low height also have the advantage that the rubber material can be quickly cooled down to a temperature close to the ambient temperature by heat exchange with the environment, since the strip-shaped molded body of the rubber mixture then has a large surface-to-volume ratio. Due to the defined length of the sections, they can be easily handled automatically, which facilitates the automated production of bales of a given size. For example, the defined length is up to one meter. The pieces are preferably transported automatically to a scale and weighed. The pieces can be stacked. Preferably, as many pieces are placed on the scale until a defined mass is reached. For this purpose, pieces can be cut off and weighed until the mass is reached. Once the defined mass is reached, the conveyor belt can be stopped in the meantime. It is also possible to increase the blade speed of the c