CS230501B1 - Method of conveyer belt splicing - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a method of joining conveyor belts which is adapted to the sensitive materials used with an adhesive system based on curable resins and to difficult working and organizational conditions in coal and mineral mining on opencast mines. unvulcanized rubber mixtures between the bonded ends of the strip and the vulcanization.

Conveyor belts require a high-quality connection of the individual sections into an endless belt for reliable operation. Especially in long-distance conveyors for the transport of coal and soil on open-cast mines, it is important for the continuous extraction of high-quality joints for a large number of them. The decisive factor for the quality of the joint is the manner of its construction and the properties of the bonding materials, the most important being adhesive and ready-to-tack.

One of the causes affecting the quality of the joint is a change in the adhesive properties and the tackiness of the fasteners during their preparation and storage. A particularly pronounced difference in adhesive properties occurs in an adhesive system based on curable resins. Such a commonly used adhesive system of bonding materials is a system based on resorcinol and a formaldehyde donor. These adhesive additives are contained both in the rubber solution and in the bonding layer. Since the reaction of resorcinol with formaldehyde on the resin is temperature and time dependent, the adhesive properties of these bonding materials can be reduced by the partial reaction of both components already during the preparation or storage of materials, if the prescribed, relatively stringent conditions for maintaining the desired properties . Taking into account the well-known difficulties resulting from the high demands on the preparation technology, in particular the adherence to mixing temperatures, and the longer from the storage conditions, it can be said that the conditions are practically not maintained in such a way as to maintain maximum and uniform values. materials.

As a result, materials with varying degrees of adhesive properties are treated for the joints, and thus less or even unsatisfactory joints are processed. Losses due to failure of conveyor belt connections are large - failures in mining and costly repetition of connections, because in many cases the belt must be lengthened.

The above drawbacks of using rubber materials with an adhesive system based on curable resins eliminates the strip bonding method characterized in that the adhesive layer between the vulcanized portion of the strip and the unvulcanized bonding layer is formed immediately prior to bonding by mixing two rubber solutions one of which contains a crosslinkable material the second contains a formaldehyde donor and the unvulcanised rubber-based bonding layer contains additives to provide ready-to-bond tack β adhesive layer.

The importance of using two rubber solutions and mixing them before use is that premature reacting of the two adhesive additives affecting the adhesive properties is avoided during preparation and storage. The high adhesion properties of the rubber solutions retained in this way then allow the use of a rubber unvulcanized bonding layer which is inserted after application of the solution between the bonded portions of the strip, without adhesive additives, only with additives to increase the tackiness.

The main advantages of application of the described method of joining, such as long-term preservation of maximum adhesive properties of fasteners, thus ensuring high reliability of conveyor belt joints and hence opencast mining operations, are additional savings in labor and material costs for repeated joints and savings as expensive adhesive additives used in the tie layer.

Exemplary embodiment

Rubber mixtures for solutions: Natural Rubber RSS I mixture 1 VÉ 50 mixture 11 parts 50 Stearic acid 0.5 0.5 Zinc oxide 3 3 Penylbetanaftylamine 0.5 0.5 Soot 12 '4,2 Silicon dioxide 6 6 Resorcin 3 0 Hexamethylenetetramine 0 ', 5 Coumarone resin liquid 1 1 Rosin 2 2 Mercaptobenzothiazyldisulfide 0.5 0 Diphenylquanidine 0.2 0 Sulfur 1.3 80.0 ', 3 80.0 Preparation of solutions: solution I solution II weight parts Mixture 1. 1 0 Mixture II. 0 1 Toluene 1 1 Gasoline, distillation curve 80 to 110 ° C 4 4

Solutions 1 and II are mixed before use in a 1: 1 weight ratio.

Rubber compound for non-vulcanized joint layer:

Natural Rubber RSS II. Stearic acid Zinc oxide Phenylbetanaphthylamine Carbon black

Coumarone resin solid

Rosin

Plasticizer '

Mercaptobenzothiazyldisulfide

Iliphenylquanidin

Sulfur

100 weight parts

0.5

170.0

An unvulcanised bonding layer of 1 mm thickness is prepared from the mixture.

The prepared solution according to the above example, mixed before use, is double coated of the bonded areas of the strip, an unvulcanised bonding layer is inserted, and the bond is vulcanized.

In the adhesion test of two bonded rubber-rubber strips as described, bonded rubber with a strength of 260 kp / cm was torn without breaking at the bond. Adhesion between polyamide pad inserts with a strength of 700 kp per 1 cm of width, tested according to ČSN 26 0381, showed a value up to three times higher than the standard, which is at least 3.6 kp per 1 cm of the width of the tested sample.

Claims (1)

A method of joining conveyor belts by coating bonded ends with an adhesive solution based on hardenable resins by inserting a layer of unvulcanized mixture between bonded ends of the belt and vulcanization, characterized in that the adhesive layer between vulcanized portion of belt and unvulcanized bonding layer is formed one of which comprises a crosslinking material forming a resin with the formaldehyde, the other comprising a formaldehyde donor, and the unvulcanized rubber-based bonding layer comprises additives to provide ready-to-bond tack with the adhesive layer.