RU2790320C1 - Method for gluing rubber and glue for gluing rubber - Google Patents

Abstract

FIELD: adhesives.

SUBSTANCE: invention relates to a method for high-strength and constant elastic gluing at least two surfaces to each other. The method for high-strength and constant elastic gluing surfaces to each other, of which one surface is a surface of constant elastic plastic, using glue, is described. In this case, the method includes a stage of application of glue on the first of surfaces to be connected, where glue contains a polyurethane component; provision of conditions, at which the first mechanism of glue curing can flow, while the specified mechanism includes a chemical reaction with formation of a chemical bond containing at least one sulfur atom; bringing of the first surface with applied glue into contact with the second surface, on which glue is optionally applied; provision of conditions, at which the second mechanism of glue curing can flow, while the specified mechanism includes formation of crystal structures of amorphous polymers.

EFFECT: absence of substances harmful for health and reduction in technical forces.

14 cl, 51 dwg

Description

The present invention relates to a method for high-strength and permanently elastic bonding to each other of surfaces, of which at least one surface is a permanently elastic plastic surface, using an adhesive. The present invention also relates to the corresponding adhesive.

Methods using cold glue for bonding rubber are known in the prior art. It is essential that such an adhesive bond be both high strength and permanently elastic so that it does not break when the rubber is deformed.

Various adhesives are used for adhesively bonding rubber surfaces by the cold glue method. Adhesives based on polychloroprene, synthetic rubber are often used. Polychloroprene adhesives contain chloroprene polymers dissolved in solvents and belong to the class of contact adhesives. In the case of contact adhesives, hardening begins after application without exposure to heat due to the evaporation of the solvent. Only after the majority of the solvent has evaporated are the surfaces to be bonded brought into contact at a high contact pressure, whereby crystalline structures are formed from the chloroprene polymers. Cohesion or adhesion within an adhesive or between an adhesive and surfaces to be bonded is based on molecular interactions such as van der Waals interactions and mechanical cohesion through diffusion of polymer molecules into the surfaces to be bonded. Solvents evaporating as the adhesive cures are an increasing problem. In most cases, volatile organic solvents are used, which can pose health hazards to the consumer such as drowsiness, nausea, headache, mucosal irritation, organ damage, and cancer. Therefore, these methods of gluing are abandoned, especially when gluing in a poorly ventilated environment, for example, on conveyor belts located underground. Since contact adhesives are thermoplastics, their use for adhesive bonding requiring a certain level of heat resistance or a wide operating temperature range is limited.

Another class of adhesives used to bond rubber surfaces to another surface are reactive adhesives. Reactive adhesives contain monomers or shorter polymer chains that bind to long chain polymers through a chemical reaction and thereby harden. With regard to the chemical reaction, among others, polyaddition mechanisms, polycondensation mechanisms or chain polymerization mechanisms are known. The reaction can be initiated thermally, photolytically, by means of atmospheric oxygen and/or air humidity, or by simple mixing of the components. In the case of reactive adhesives, the main distinction is made between one-component adhesives and two-component adhesives, with the respective embodiment determined by the monomers used and the type of chemical reaction. In the case of two-component adhesives, the mixture is prepared before use. Cohesion and adhesion occur due to the formation of chemical bonds and molecular interactions. Reactive adhesives have a pot life that depends on the chemical reaction. The reactive adhesive can be processed within pot life; once the pot life has been exceeded, the viscosity of the mixture becomes so high that the surfaces to be bonded can no longer be wetted. One of the difficulties associated with two-component adhesives is maintaining the mixing ratio and uniform mixing, which are critical in terms of providing a high strength and permanently elastic bond. Reactive adhesives often contain volatile solvents in which monomers or shorter polymer chains are dissolved. Such solvents evaporate during use and become hazardous to the user. As noted above with contact adhesives, the solvent precludes the use of such adhesives in poorly ventilated environments, such as underground conveyor belts.

In addition, hot methods for joining rubber surfaces, including vulcanization, are known from the prior art. Such a method uses curing solutions containing, among other things, dissolved rubber compounds, various solvents, cross-linking agents such as sulfur, peroxides or metal oxides, and vulcanization accelerators such as zinc oxide, 2-mercaptobenzothiazole or dithiocarbamates. The vulcanizing solution is applied to the rubber surfaces to be bonded and pressed with a vulcanizing press at high pressure and high temperature for several hours. The chemical reaction of rubber molecules with crosslinking agents, in the case of sulfur with the formation of sulfur bridges, leads to the crosslinking of rubber molecules. Vulcanization involves the use of volatile and harmful solvents such as trichlorethylene and, in some cases, toxic vulcanization accelerators. Vulcanization also requires a high level of technical effort and specialist knowledge. In particular, in remote and/or hard-to-reach places such as mines (especially underground), the listed materials and the required technical equipment, such as vulcanizing presses (especially explosion-proof vulcanizing presses), are often not available, so, for example, damage to conveyor belts leads to long downtime and cannot be avoided using conventional methods.

The object of the present invention is to provide a method for highly durable and permanently elastic bonding to each other of at least two surfaces, of which at least one surface contains rubber, using an adhesive that does not have the disadvantages listed above or at least minimize them. Preferably, the proposed method can be implemented quickly, without high equipment costs, as far as possible independent of supply networks, such as power supply networks and / or water supply networks, and in poorly ventilated places, as far as possible without endangering the health of working personnel. For the latter reason, it would be preferable to do without the use of substances harmful to health, while said method should not require great technical effort. Furthermore, it is an object of the present invention to provide an adhesive for use in the method of the present invention.

This problem is solved using a method of high-strength and permanently elastic bonding to each other of at least two surfaces, of which at least one surface is a permanently elastic plastic surface according to claim 1, and using glue according to claim 8.

An essential aspect of the present invention is a method for high-strength and permanently elastic bonding to each other of at least two surfaces, of which at least one surface is a permanently elastic plastic surface, using an adhesive, said method comprising the steps of:

a) applying adhesive to at least the first of the surfaces to be joined,

b) providing conditions under which at least the first mechanism of adhesive hardening can proceed, said mechanism comprising at least a chemical reaction to form a chemical bond containing at least one sulfur atom,

c) bringing the first adhesive-applied surface into contact with a second surface, optionally also adhesive-applied,

d) providing conditions under which at least a second mechanism of hardening of the adhesive can proceed, said mechanism comprising at least the formation of crystalline structures from amorphous polymers.

By high-strength bonding is meant any bonding that allows bonding of at least two surfaces, of which at least one surface is a permanently elastic plastic surface, as well as bonding the surfaces to each other in such a way that it is difficult and preferably not possible at all (at least measure without destruction) separated from each other. As a result, the bonded surfaces can be subjected to high loads and stresses while reducing the risk of reseparation of the surfaces when high forces are applied.

In step d), the adhesive preferably passes through the so-called step B. This step requires a particularly long processing time before the surfaces to be glued have to be bonded. In addition, a particularly high initial tack can be achieved.

In steps a) and/or b), a portion of the adhesive preferably diffuses into at least one of the surfaces to be bonded. Such a portion of the adhesive more preferably diffuses into one of the surfaces to be bonded to a depth of at least 1 µm, preferably even further at least 10 µm, preferably at least 50 µm, more preferably at least 100 µm and particularly preferably from 50 to 300 µm.

In this context, permanent elastic bonding is understood to mean any bonding that allows at least two surfaces to be bonded, of which at least one surface is a permanently elastic plastic surface, the resulting adhesive bond between the surfaces having a high degree of elasticity, in other words, deformability and elongation. This elasticity of the adhesive bond is especially important when bonding rubber surfaces, since rubber surfaces can deform and stretch. Since rubber is the material of choice in applications where its deformability and extensibility are constantly exploited, the shapes of the adhesion sites or adhesive joints are also subject to such changes. Due to the high elasticity of the adhesive bond, tearing of the adhesive bond can be prevented or reduced, and the resulting separation of the bonded surfaces can be avoided.

In a preferred embodiment, the permanently elastic plastic, the surface of which is subjected to bonding, contains rubber. In connection with the present invention, the material "rubber" should generally be understood to mean any form of vulcanizate of natural and/or synthetic rubbers. While the present invention has been described using rubber as an example, the present invention should nevertheless be understood simply as an illustrative embodiment and, in general, a method for bonding two surfaces to each other, of which at least one surface is a permanently elastic plastic surface. . Similarly, this also applies to a permanently elastic adhesive which, even when described using rubber as an example, is also generally intended to permanently elastically bond two surfaces, in which case one of the surfaces to be bonded to each other is a surface permanently elastic plastic.

In addition, it is possible that at least one surface that is bonded to the permanently elastic plastic surface is also a permanently elastic plastic, preferably rubber or contains rubber, or consists of or contains a material selected from the group consisting of metal, glass, ceramics, wood and textiles.

Due to at least two adhesive solidification mechanisms, wherein at least the first adhesive solidification mechanism includes at least one chemical reaction to form a chemical bond containing at least one sulfur atom, and wherein at least the second adhesive solidification mechanism includes least the formation of crystalline structures from amorphous polymers, a particularly strong adhesive bond is achieved. The chemical reaction to form a chemical bond containing at least one sulfur atom during the first adhesive curing mechanism preferably proceeds by chemical reaction of a reactive group of the adhesive, preferably containing a sulfur atom, an oxygen atom or (preferably a C-C-) double bond, said reactive the permanently elastic plastic group contains at least one sulfur atom and/or (preferably C-C-) double bond. This mechanism leads to particularly strong adhesion between the boundary layers of the adhesive and the permanently elastic plastic. Particularly preferred is the formation of a sulfur-sulfur bond, a sulfur-oxygen bond, a sulfur-carbon bond, each of which provides a particularly strong adhesion between the boundary layers of the adhesive and the permanently elastic plastic. In addition, it is also possible to form a sulfur-hydrogen bond and to adhere (for example, via van der Waals forces) to another component of the compound.

Due to the formation of crystalline structures from amorphous polymers during the second mechanism of adhesive hardening, the polymer molecules are preferably arranged in such a way that the association sites are enlarged and thus the mutual attraction between the polymer molecules is enhanced.

In contrast to prior art methods for high-strength and permanently elastic bonding to each other of at least two surfaces, of which at least one surface is a permanently elastic plastic surface, the method according to the present invention provides the advantage that the first the curing mechanism and the second adhesive curing mechanism preferably proceed without great technical effort and high temperatures, which are necessary for vulcanization. This provides a simple and safe application of the specified method. Therefore, the proposed method is preferably also suitable for consumers who do not have special training and/or are located in an inaccessible environment and/or without a power source. Thus, the proposed method provides significant advantages in comparison with methods for gluing rubber surfaces with significantly increased technical and material costs, such as vulcanization.

In addition, the presence of two different curing mechanisms according to the present invention represents a significant advantage over methods in which the adhesives used have only one curing mechanism. When using, for example, contact adhesives, bonding is based solely on the formation of crystalline structures from polymers. Thanks to the inventive combination of two different curing mechanisms, the advantages of both curing mechanisms can be advantageously used, and thus a significant strengthening of the adhesive bond can be achieved.

It has been found that suitable operating and/or ambient conditions for steps b) and/or d) of the proposed method are ambient and/or material temperatures ranging from -40 to +80°C, preferably from -20 to +70°C, more preferably -5 to +65°C and particularly preferably +5 to +60°C. If, due to environmental conditions outside the specified range, processing is not possible or only possible with difficulty, it is advisable to at least condition the adhesive and the areas to be glued until the above temperature range is reached. Processing within the temperature ranges given is preferred due to easier handling and suitable adhesive reaction/set times in most cases. However, it has been shown that the adhesive described above can be processed in an additional temperature range, namely, preferably at least in the range from -40 to 120°C. At temperatures that deviate from the preferred processing temperatures listed above, the processing time must be adjusted accordingly.

Regardless of the above preferred operating and/or ambient temperatures, it is also preferred that the bonding surfaces are at least substantially dry and free of dust, grease and/or oil.

The adhesive described above may include other components such as solvents, primers, fillers, or combinations thereof. Solvents may be present, for example, at a relative content of up to 85% of the mass. (calculated on the total weight of the adhesive in the uncured state). Unless a percentage is expressly defined otherwise in the following description, the percentage is to be understood in each case as a percentage by weight based on the total weight of the adhesive in the uncured state. Solvents in the adhesive composition have the advantage that they can facilitate diffusion of the adhesive-active components within the adhesive. In particular, in the case of the preferred multi-component adhesives, accelerated diffusion can be advantageous.

However, studies have shown that sufficient mixing of the components and excellent adhesive properties can be achieved even without high relative solvent contents. Thus, it turned out to be preferable to reduce the relative content of the solvent to less than 50% wt., preferably less than 30% wt. In a preferred composition, the adhesive contains 10 to 20 solvents, preferably 10 to 15 solvents.

It turned out to be preferable that the proposed method uses an adhesive containing less than 5% of the mass. solvent, preferably less than 3% wt. solvent, more preferably less than 1 wt%. solvent, it being particularly preferred if a solvent-free adhesive is used so that the minimum time interval between steps b) and c) required for the solvent to evaporate is less than 1 hour, preferably less than 30 minutes and more preferably less than 15 minutes at environment from 20 to 25°C. This, and in particular the particularly preferred use of a solvent-free adhesive, can ensure that there are no risks to humans and the environment caused by volatile solvents, and also ensure that such a process can be carried out without the application of large-scale security measures and in a bad way. ventilated places. In addition, with the particularly preferred use of a solvent-free adhesive, it is possible to minimize the required minimum time for evaporation of the solvent between steps b) and c) at an ambient temperature of 20 to 25°C, thus making it possible to reduce the duration of the proposed method and leads to a reduction in the working time of the consumer.

In a preferred embodiment, the adhesive is a two-component adhesive which is preferably placed in a dual cartridge and then preferably applied to the bonding surface with a compatible cartridge gun. It turned out that the use of two-component adhesives is advantageous, since the two-component adhesive is cured only after mixing the two components of the adhesive. Since these two components are contained separately from each other in the dual cartridge and cannot interact with each other, a good shelf life can be ensured. According to a preferred embodiment of the adhesive, its suitability can thus be guaranteed for a period of at least one year, preferably at least 18 months and particularly preferably at least 2 years. Using a compatible cartridge gun, these two components can be applied to the surfaces to be loaded, at a given mixing ratio (preferably in the range of 10:1 to 1:3, particularly preferably 1:1, in each case by volume).

In one embodiment of the proposed method, it is preferable that the adhesive is applied to the surface to be glued in an amount of less than 500 g/m ² , preferably less than 300 g/m ² , more preferably less than 200 g/m ² and particularly preferably less than 100 g/m ² . This guarantees a high level of savings due to the small amount of adhesive needed for gluing. In addition, high-strength and permanently elastic adhesive joints can be achieved in this way with very small gap widths.

Preferably, before step a), at least the surface containing the permanently elastic plastic, preferably both surfaces to be bonded, are cleaned and roughened, preferably using a tool selected from the group consisting of roughening devices, angle grinders, ( belt planers, brushes, sanding belts, grinding wheels, milling cutters and other tools, by means of which the production-related separating layer located on said surface is also removed, while the best bonding can be achieved for the permanently elastic plastic surface. In addition, in the case of adhesive bonding processes, it is not necessary to pre-treat the adhesive surfaces with a chemical cleaner and/or adhesion promoter known from the prior art. Avoiding the use of such partially volatile substances is particularly advantageous in poorly ventilated environments, such as underground.

Preferably, at least one, preferably both, of the surfaces to be bonded when exposed to a test substance with a surface tension below 50 mN/m, preferably ≤ 46 mN/m, more preferably ≤ 38 mN/m, particularly preferably ≤ 30 mN /m, in particular, preferably ≤ 20 mN/m, had surface wetting due to the test substance. A suitable uniform wettability ensures sufficiently uniform wetting of the adhesive on the surfaces to be bonded and thus a uniform adhesive force over the entire adhesive surface.

One variant of the proposed method is characterized in that, after step d), the surfaces to be glued are secured against each other and/or subjected to pressure with a suitable fastening device, preferably a pressure device, the pressure device preferably comprising at least one pressure element, particularly preferably at least one screw clamp, and contains at least one pressure distribution element, wherein at least one pressure distribution element distributes the pressure generated by at least one pressure element over the entire surface including the gluing area . Such a preferred pressurization device provides accurate bonding without changing the position of the surfaces and optimal adhesion, since the pressure generated is evenly distributed over the bonding area, while ensuring sufficient contact of the surfaces to be bonded.

The preferred embodiment is also characterized in that the surfaces to be glued are parts of a permanently elastic plastic belt, preferably a conveyor belt, the surfaces to be glued are preferably opposite ends of the permanently elastic plastic belt, which are connected to form an endless belt or placed on opposite ends. sides of a damaged area, in particular a hole or tear. However, such a method is not limited to the above connection of opposite ends of a permanently elastic plastic belt or an endless belt conveyor belt. Naturally, several previously separate sections of tape can also be connected to form one tape. This simplifies the transport of the belt sections to the site of use, since the belt sections can be transported individually and, due to their shorter length compared to the whole belt, they are easier to handle. In an inaccessible environment, such as underground, there is generally no need for heavy tape handling equipment. Rather, the individual sections of the belt can be transported to the shaft and spliced there.

The high-strength and permanently elastic curable adhesive according to the present invention, obtained and placed for bonding to each other at least two surfaces, of which at least one surface is a permanently elastic plastic surface, is characterized, in particular, by the fact that it is an adhesive , cured according to at least two different solidification mechanisms, wherein the first solidification mechanism includes at least one chemical reaction to form a chemical bond containing at least one sulfur atom, and the second solidification mechanism includes at least the formation of a crystalline structure from amorphous polymers . Due to the combination of properties consisting in the formation of a chemical bond containing at least one sulfur atom and the formation of crystalline structures from amorphous polymers, such an adhesive not only provides adhesion to the surfaces of permanently elastic plastics, but also creates an extremely strong adhesion known for contact adhesives.

The adhesive described above preferably contains a polyurethane component. Surprisingly, it has been found that such a component, particularly preferably in one embodiment as a multi-component adhesive, preferably a two-component adhesive, leads to particularly strong bonds.

Also preferred is the implementation of the adhesive containing less than 5% wt. solvent, preferably less than 3 by weight of the solvent, more preferably less than 1% of the mass. solvent and particularly preferably solvent-free. This embodiment has proven to be particularly suitable for applications in environments that are difficult to supply with fresh air (eg underground mines). In addition, such an embodiment makes it possible to prevent the environmentally harmful properties of the adhesive. Surprisingly, there is sufficient diffusion of the components even in the absence of a solvent, so that a sufficiently large adhesive force is formed over a large area.

The adhesive according to the invention is preferably characterized in that its behavior is determined by the choice and proportion of the sulfur-adding component and the polyurethane component, so that at least two different curing mechanisms can be initiated at an ambient temperature in the range of -50 to +80°C. , preferably from -30 to +70°C, more preferably from -10 to +65°C and particularly preferably from 0 to +60°C. Setting parameters for curing in such a temperature range has proven to be advantageous since, in this region, the surfaces of the permanently elastic plastics to be bonded are not damaged and yet rapid reaction or curing occurs.

It is also preferred that the peel strength of the adhesive in the cured state is > 6 N/mm ² , preferably > 8 N/mm ² , preferably > 10 N/mm ² , more preferably > 12 N/mm ² and especially preferably > 15 N/mm 2 mm ² . This peel strength has proven to be particularly advantageous in terms of joining the ends of conveyor belts, as it ensures that even a constant tensile load will not break the joint.

According to a preferred embodiment of the adhesive, the elastic modulus of the proposed adhesive in the cured state is 0.2 to 40 N/mm ² , preferably 0.3 to 30 N/mm ² , and particularly preferably 0.4 to 20 N/mm ² . This range of modulus of elasticity has been found to be advantageous since there is the necessary resilience in this region to be able to maintain the deformation of the surfaces of the permanently elastic plastics to be bonded. This is especially important when joining the ends of conveyor belts, as they pass over deflection rollers, and the join must also be able to support the deformation that occurs there without being damaged.

Preferably, the cured peel strength of the adhesive on the surface of the styrene butadiene rubber is > 4 N/mm, preferably > 6 N/mm, preferably > 8 N/mm, more preferably > 10 N/mm, and particularly preferably > 12 N/mm. It has turned out that when joining the ends of conveyor belts, such peel strength is particularly advantageous, since peel forces can occur in the conveyor belts, in particular in the area of the deflection rollers, so that the joint can also withstand the peel forces occurring there without being damaged.

According to a preferred embodiment, the hardness Shore A of the adhesive in the cured state is from 50 to 99 Shore, preferably from 55 to 95 Shore and particularly preferably from 60 to 90 Shore (measured according to DIN EN ISO 868 or DIN ISO 7619 -1). Such a range has turned out to be advantageous since there are the same material properties as in the range of surfaces to be bonded. Therefore, the transitional area from the surfaces to be bonded to the bonding site is preferably fluid. Shore A hardness can be determined, for example, from the degree of crosslinking of the adhesive and possible fillers.

Preferably, the cured shear strength of the adhesive on the surface of metals, galvanized steels and/or styrene butadiene rubber is > 4 N/mm ² , preferably > 6 N/mm ² , preferably > 8 N/mm ² , more preferably > 10 N/mm ² and especially preferably > 12 N/mm ² . It has turned out that when joining the ends of conveyor belts, this shear strength is particularly advantageous, since shear forces can occur in the conveyor belts, in particular in the area of the deflection rollers, so that the connection point can also withstand the shear forces occurring there without being damaged.

In addition, the above adhesive and the method described above can also be used to bond any permanently elastic surfaces. This applies not only to belts of any type, such as belts for round balers or other agricultural equipment and conveyor belts in the raw materials and mining industries, but also to surfaces other than belts. Another possible application is, for example, the bonding of a permanently elastic plastic to sensitive surfaces. For example, the surfaces to which the permanently elastic plastic is to be applied may be the surfaces of drums (for example, as a support for a drive for conveyor belts) or the inner surfaces of containers (for example, hoppers or funnels) into which bulk material is to be placed. (for example, with sharp edges). In addition, permanently elastic plastics (e.g. rubber), for example in the form of anti-slip mats or protective pads, can also be adhered to any surface on which it is necessary to prevent objects placed on it from sliding, or an object placed on such a surface must be especially protected.

Another advantage of the method described above and the adhesive described above for this purpose is that after the second mechanism of hardening or formation of crystal structures in the adhesive, the connection between the first and second surfaces created by the adhesion site is immediately (at least at least a little) elastic. Even if, as described above, the full cure waiting time is partially preferred, loading (preferably below the maximum load) is already immediately possible.

Furthermore, it is preferred that both the method described above and the adhesive can be used for different types of conveyor belts. In particular, the surfaces to be bonded can be single-layer or multi-layer surfaces, in particular two-layer conveyor belts. Additionally and independently, the surfaces may be the surfaces of reinforced or non-reinforced conveyor belts. In this respect, reinforced conveyor belts should be understood to mean conveyor belts reinforced with one or more textile elements (eg textile webs) as well as conveyor belts reinforced with one or more metallic elements (eg steel cables). Thus, in contrast to prior art pressure sensitive adhesives, the adhesive of the present invention preferably makes it possible to adhere also to textile materials, metals such as steel, and other materials, and thus enables the listed materials to be bonded by means of surface to be bonded to other surfaces without rubber.

The proposed method can preferably be used for both step connections and pin connections. Pin connections can be made both with metal (for example, a steel cable), and with plastics reinforced with textile material, as well as with non-reinforced plastics.

Additional advantages, objects and properties of the present invention are explained on the basis of the following description of the accompanying drawings, which show the use of a high strength and permanently elastic adhesive described above, as well as a method of high strength and permanently elastic bonding to each other of at least two surfaces, of which at least one surface is a permanently elastic plastic surface, with an adhesive. Parts of the gluing apparatus and/or steps of the proposed method, which in the drawings are at least substantially similar in terms of their function, can be identified by the same reference numerals, such parts and/or steps of the proposed method need not be numbered and described. on all drawings.

The drawings show:

Fig. 1: two additional ends of the conveyor belt, prepared for joining with a high-strength and permanently elastic adhesive;

Fig. 2 is a sectional view of the stepped profile of the end of a conveyor belt prepared for joining with a high-strength and permanently elastic adhesive;

Fig. 3 is a side view of a possible connection between two ends of a conveyor belt with a high strength and permanently elastic adhesive;

Fig. 4a is a schematic representation of a stage of the proposed method for creating a stepped profile at the end of a conveyor belt;

Fig. 4b: schematic representation of a step of the proposed method for roughening the surface of a stepped profile to be bonded to the end of a conveyor belt;

Fig. 4c is a schematic representation of a step of the proposed method for applying adhesive to a stepped profile at the end of a conveyor belt;

Fig. 4d: schematic representation of a stage of the proposed method for distributing adhesive along a stepped profile at the end of a conveyor belt;

Fig. 4e: schematic representation of the stage of the proposed method for gluing the stepped profiles of the two ends of the conveyor belt;

Fig. 4f is a schematic representation of a step of the proposed method for post-processing a splice gap between two ends of a conveyor belt.

Fig. 4g: schematic representation of a stage of the proposed method for pressurizing with a holding device;

Fig. 5a is a schematic representation of a stage of the proposed method for roughening the adhesive surfaces of the skin of the drum;

Fig. 5b is a schematic representation of a stage of the proposed method for applying glue to a drum;

Fig. 5c: schematic representation of a stage of the proposed method for applying adhesive to the skin of the drum;

Fig. 5d is a schematic representation of a step of the proposed method for gluing one end of the drum skin to the drum;

Fig. 5e: schematic representation of a stage of the proposed method for wrapping a drum with a drum skin;

Fig. 5f: schematic representation of a step of the proposed method for shortening the overlapping ends of the skin of the drum;

Fig. 5g: schematic representation of a stage of the proposed method for gluing together the ends of the skin of the drum;

Fig. 5h is a schematic representation of a step of the proposed method for removing the edges of the skin of the drum, protruding beyond the side surfaces of the drum;

Fig. 6: schematic representation of a cross section of a conveyor belt reinforced with steel cable belts;

Fig. 7a-c: schematic representations of various options for possible connections of the ends of a conveyor belt reinforced with steel cable belts;

Fig. 8a, b: schematic cross-sectional views of the connected ends, or ends to be connected, of a conveyor belt reinforced with steel cable belts;

Fig. 9a: a schematic representation of a stage of the proposed method for preparing the ends to be joined of conveyor belts reinforced with steel cable belts;

Fig. 9b: schematic representation of an additional step of the proposed method for preparing the ends to be joined of conveyor belts reinforced with steel cable belts;

Fig. 9c: schematic representation of a step of the proposed method for forming pins that can be connected to each other, at the ends to be connected, of conveyor belts reinforced with steel cable belts;

Fig. 9d: a schematic representation of a step of the proposed method for applying adhesive to the surfaces of the ends to be connected to each other of conveyor belts reinforced with steel cable belts;

Fig. 9e: schematic representation of a stage of the proposed method for gluing the pins of the ends to be connected to each other of conveyor belts reinforced with steel cable belts;

Fig. 9f: a schematic representation of a step of the proposed method for applying adhesive to pins connected to each other of conveyor belts reinforced with steel cable belts;

Fig. 9g: schematic representation of a conveyor belt fixed for adhesive curing and reinforced with steel cable belts;

Fig. 10a, b: schematic representations of suitable fastening devices for uniform distribution of pressure throughout the connection;

11a-c: schematic representations of the steps of the proposed method for preparing the ends to be joined of conveyor belts reinforced with steel cable belts;

Fig. 11d is a schematic representation of a step of the proposed method for forming a plurality of cuts or grooves located between the baffles, each of which surrounds the steel cable;

Fig. 11e: schematic representation of a stage of the proposed method for preparing surfaces to be bonded;

Fig. 11f, g: schematic representations of the process steps for applying adhesive to the surfaces of the ends to be connected to each other of conveyor belts reinforced with steel cable belts;

Fig. 11h: schematic representations of the steps of the proposed method for introducing tensile load transmission means;

Fig. 11i: schematic representation of a stage of the proposed method for applying the top layer;

Fig. 11j: a schematic representation of a step of the proposed method of using rails without soles for fixing a joint in the transverse direction;

Fig. 11k: schematic representation of a conveyor belt fixed for adhesive curing and reinforced with steel cable bands;

Fig. 12a is a plan view of a damaged section of a conveyor belt during bevelling of the damaged section in preparation for their repair;

Fig. 12b is a sectional view of a damaged section of a conveyor belt during surface treatment to ensure sufficient adhesion of the adhesive;

Fig. 12c shows a damaged section of a conveyor belt with integrated textile reinforcement;

Fig. 12d: image of the damaged section of the conveyor belt when the adhesive is introduced into the damaged section;

Fig. 12e is a sectional view of a repaired damaged section of a conveyor belt during adhesive curing;

Fig. 12f is a sectional view of a repaired damaged section of a conveyor belt during mechanical reworking;

Fig. 13: illustrative curve between temperature and recommended processing time.

Figure 1 shows two additional ends 1a, 1b of a conveyor belt prepared for joining with a high-strength and permanently elastic adhesive. Said ends are arranged opposite each other in such a way that they allow the possible establishment of a connection between the two ends 1a, 1b of the conveyor belt by means of the high-strength and permanently elastic adhesive described above. The ends 1a, 1b of the conveyor belt 1 to be glued may be the ends of the same conveyor belt 1 or of different conveyor belts. Thus, the adhesive described above is suitable, for example, for joining (rubber) conveyor belts to form an endless belt or for assembling such an endless belt 1 from several easy-to-handle parts of conveyor belts.

As can be seen in figure 1, along with the stepped ends 1a, 1b of the conveyor belt, strips 2a, 2b are also used, in this case with a trapezoidal cross section, which can cover the corresponding joint gap 3a, 3b on the outer top layer 4a, 4b of the conveyor belt 1. Therefore, the uppermost 5c or the lowermost stepped strips 5a are configured to correspond to said strip 2a, 2b. The opposite outer (top) layer 4a, 4b of the conveyor belt 1 is similarly constructed accordingly.

Figure 2 shows a sectional view of the stepped profile of the end 1 of a conveyor belt prepared for joining with a high-strength and permanently elastic adhesive. As can be seen from such an image above, it is preferably provided that the steps 5a, 5b, 5c do not run parallel to the end 1a of the conveyor belt, but rather run at an angle in the range of > 0° to < 90° relative to said end. As a result of the parallel sides 6a, 6b of the conveyor belt 1 and the sides of the steps that do not extend at an angle of 90°, each step 5a, 5b, 5c forms a trapezoidal shape. The trapezoidal configuration of the steps 5a, 5b, 5c has the advantage that when said connection is subjected to tensile stress, the entire contact between the two steps 5a, 5b, 5c is not simultaneously subjected to tensile stress, which could cause the connection to break. Rather, the edge region is subjected to tensile stress first, and only then further areas of contact between the two steps 5a, 5b, 5c. In addition, the stress on the joint can be reduced by other components of the conveyor system (eg, drive rollers, drive means, shifters, scrapers), since only parts of the joint are in contact with these components.

The individual steps 5a, 5b, 5c may each have the same width, as in the example shown. However, this is not absolutely mandatory. Steps 5a, 5b, 5c with different step widths can also be used depending on requirements. This can be advantageous, for example, if the total connection length is to be as short as possible. In this case, the more stressed steps 5a, 5b, 5c can be made longer than the less stressed steps.

Figure 3 shows a side view of a possible construction of a connection between the two ends 1a, 1b of a conveyor belt with a high-strength and permanently elastic adhesive 7. Such bonding can be achieved with an adhesive 7 as described above located between the contact surfaces of the individual steps 5a, 5b, 5c. In the example shown, the tape consists of two top layers 4a, 4b and a core divided into 4 levels or layers 8a, 8b, 8c, 8d. Thus, the four levels or layers 8a, 8b, 8c, 8d and the corresponding tape end 1a, 1b form 3 steps 5a, 5b, 5c. If they are connected to each other in a complementary way, they again form a core divided into 4 planes 8a, 8b, 8c, 8d. The length of the respective joint and the number of steps 5a, 5b, 5c can be chosen, for example, according to DIN 22102. The joint gaps 3a, 3b between two respective top layers 4a, 4b are each covered by a band 2a, 2b to bridge the joint gap. Said strip can also be attached using the adhesive 7 described above.

Figures 4a-g show the individual steps of the proposed method for joining the ends 1a, 1b of a conveyor belt. By way of example, figure 4a shows at the end 1a of a conveyor belt that the contact point to be joined between the ends 1a, 1b of the conveyor belt is suitably prepared before gluing. In particular, it is preferable that before gluing the ends 1a, 1b of the conveyor belt are equipped with a stepped profile. The stepped profiles of the two ends 1a, 1b of the conveyor belt to be connected are designed in such a way that when the ends 1a, 1b of the conveyor belt overlap, each of them has the same thickness in total. Such an embodiment makes it possible, on the one hand, to prevent an undesirable increase in the thickness of the conveyor belt 1 in the area of ​​the overlap. In addition, an increase in the contact area available for bonding is provided. This is advantageous in terms of connection stability. As shown in Figure 2 above, it is preferred that the steps 5a, 5b, 5c do not run perpendicular to the longitudinal direction L of the conveyor belt 1, but run relative to that direction at an angle α of, for example, 5° to 85°, preferably 10° up to 70°, particularly preferably from 15° to 55° and particularly preferably from 15° to 45°. Such an orientation of the individual steps 5a, 5b, 5c, deviating from the transverse direction B of the tape 1, means that on the one hand the contact area is further increased, and on the other hand the tensile load acting in the longitudinal direction L of the tape 1 does not act perpendicular to the mating surface of the individual steps 5a, 5b, 5c. This further minimizes the risk of adhesive bond failure and damage to other system components.

As can be seen in figure 4a, one of the ends of the tape is first secured to a suitable base 9, such as a flat workbench. This can be done, for example, with screw terminals 10 and optionally with suitable pressure distribution devices 11 . The individual layers 8 are then removed in turn to form the steps 5 described above. As described above in relation to figure 2, and also shown in figure 4a, the steps 5 removed accordingly have a trapezoidal profile. If the individual layers 8 also contain a textile layer (not shown in this figure), this is also removed. Figure 4a shows how the abutting edges of the individual steps 5 are obtained by introducing a cut. The individual layers 8, such as the rubber cover 4, can then be removed. If necessary, use a band knife (not shown). Other layers are removed in the same way.

The other side of the belt or the other end of the conveyor belt 1a, 1b must be prepared in the same way. Of course, it should be noted that the angle α with respect to the longitudinal direction L of the tape 1 passes in such a way that in the case of overlap, the steps 5 run parallel and are on the opposite side, therefore, when the corresponding ends 1a, 1b overlap, the steps 5 are closed, so that the steps 5 and the joined the surfaces of the two ends 1a, 1b of the tape come into contact and as a result form an overall height of the tape corresponding to the original height of the tape.

After the above preparation procedures, the contact surfaces are roughened, for example with a wire brush 12, as shown in FIG. 4b, in order to improve the adhesion of the adhesive 7 and thus also of the ends 1a, 1b of the tape to each other. The roughening is preferably carried out in a transverse direction with respect to the transport direction. Then, as shown in figure 4c, the adhesive 7 can be applied. This can be done, for example, using a cartridge gun 13. However, before application, it is recommended to check the alignment of the ends 1a, 1b of the conveyor belt to be connected and the dimensional accuracy of the connection, and install a protective a film 28 between the base or workbench 9 and the ends 1a, 1b of the conveyor belt to be connected, in particular to avoid adhesive contamination. After gluing, the adhesive 7 described above, in contrast to the contact adhesives known from the prior art, still allows the individual elements to be moved relative to each other, while taking into account the already existing adhesive force and in many cases handling long and/or wide and/ or heavy conveyor belts 1 which is difficult in any way, position adjustment is difficult and should be avoided if possible.

Further, in order to achieve uniform adhesion, it is advisable, as shown in figure 4d, to distribute the adhesive 7 using a spatula 14 or a brush. All contact surfaces must be completely moistened, preferably up to the very point. Since the adhesive 7 begins to cure immediately after application to the contact surfaces, it is necessary to measure the time from application. The longer the adhesive 7 can cure at this stage, the stronger the initial adhesion that can be achieved. In the present example, optimal initial adhesion is achieved 7 to 10 minutes after application of the adhesive 7. Longer waiting times increase initial adhesion, which may be advantageous, but makes it difficult to adjust the position of tape ends 1a, 1b in subsequent steps.

The opposite end 1a, 1b of the conveyor belt (to be connected) must also be prepared.

It is also expedient to make preparations for the subsequent fastening and application of pressure at the point of adhesion no later than after such a step of the proposed method. For example, as shown in Figure 43 (???) and the following figures, parts of the pressurization device and/or fastening device 10, 11 may in this case be located under the part of the conveyor belt to be connected.

It would also be possible at this point to place the gap-bridging band 2a on the side which, for example, rests on parts of the pressurization device and/or the fastening device 10, 11, since such access may subsequently be difficult.

After the waiting time specified for the respective adhesive 7 has elapsed and the required initial adhesion has been set accordingly, the ends 1a, 1b of the tape are connected together as shown in figure 4e. In order to achieve a good contact and, for example, to avoid the formation of bubbles at the point of contact, it is expedient to apply pressure to the point of gluing, for example by means of a pressure roller 15 or a wheel, from the inside to the outside in order to force out any air bubbles. In this state, in contrast to prior art contact adhesives, the position of the tape ends 1a, 1b relative to each other can be corrected as long as the adhesive 7 is not yet too hardened.

In order to ensure that the surface of the now connected ends 1a, 1b of the conveyor belt is as flat as possible in the area of the joint, it is advisable, as described above, to insert a so-called tape 2a, 2b into the upper layer(s) 4a, 4b to bridge the joint gap. Such a gap-bridging band 2a, 2b is preferably a rubber or polyurethane band with or without a textile insert. The procedure for embedding and pressing the top tape 2b to bridge the joint gap into the outer top layer is shown in figure 4f. Lastly, if necessary, the entire joint surface, including the joint gap bridging tape 2b, must be rolled vigorously starting from the center to expel all air bubbles and ensure sufficient contact of the bonding surfaces with each other.

For final curing, the joint must be clamped in a suitable fastening device 10, 11. The application of pressure by means of a typical fastening device 10, 11 is shown in figure 4g. In this example, the curing time to reach a certain (hand or temper) hardening strength is approximately 60 minutes at 23°C. The required time depends on the composition of the adhesive and the temperature. Then the connection must be checked again. In the present example, the functional strength of the joint is achieved after approximately three to four hours. After this time, the fastening device 10, 11 can be removed and the tape can be re-processed, if necessary. The reprocessing steps may include, for example, cutting or grinding the protruding portions of the tape. By means of such a method it is possible to ensure a permanent connection of the ends of the tape without the need for said tape to have a greater thickness in this area than in other areas. Tape 1 is ready for use in a few hours. No need for vulcanization. This means that the proposed method can be used independently and, moreover, in places that are difficult to access. For example, after 8 hours, the conveyor belt 1 thus connected can be used again with maximum load.

A great advantage of the adhesive 7 described above and the method of using such adhesive 7 is that said adhesive not only adheres well to rubber, but also adheres very well to other materials, including those that cannot be elastically deformed. As a result, the adhesive 7 is also suitable for covering metal drums 16, for example with rubber linings 17. An example of how this can be done is shown in figures 5a-h. First, as shown schematically in FIG. 5a, the bonding surfaces 18 and the cutting edges 19 of said skin 17 are roughened. This can be done, for example, with a buffing device 12 known from the prior art, or with an angle grinder. In order to ensure the best adhesion of the adhesive 7 to the bonding surfaces 18, such bonding surfaces 18 must be cleaned before applying the adhesive 7. This cleaning is particularly useful in terms of removing grease and oils, as well as chips and dust generated during roughening. Cleaning is preferably done with a broom. The use of solvents should be avoided. Even though this is not explicitly shown in FIG. 5a, in order to obtain a permanent adhesive bond, the roughening should take place as far as possible in a transverse direction with respect to the direction of the pulling force.

After the coating has been prepared as described above, the adhesive 7, as shown schematically in figure 5b, is first applied to the surface of the drum 16 using a cartridge gun 13. The adhesive 7, which is first applied in stripes, is then spread evenly with a brush , spatula 14 or other suitable tool. As has been shown, it is advantageous to use a certain amount of adhesive, which is approximately 100 to 150 g/m². This amount can be applied in one layer. A second layer is usually not required. It should be ensured that the entire surface of the drum 16 to be coated is completely moistened.

Since the adhesive 7 begins to cure after being applied to the drum 16, it is important to record the time after application. A long period of time between application and contact with the skin 17 increases the initial adhesion between said parts 16, 17, but if the initial adhesion is too high, correct alignment becomes more difficult. Therefore, immediately after applying the adhesive 7 to the drum 16, said adhesive 7 must also be applied to the inner surface 18 of the skin 17. As shown schematically in the figure. 5c, the adhesive 7 is applied to said surface 18, for example with a cartridge gun 13. In this case, the adhesive 7 should also be spread evenly with a spatula 14, brush or similar tool. The surface 18 of the skin 17 should be as completely wetted as possible.

Before bringing the skin 17 into contact with the drum 16 to be coated, the adhesive 7 must dry for a predetermined time to achieve the required initial adhesion. Such a time interval differs depending on the composition of the adhesive 7. Different time intervals can be set by using different compositions of different adhesives 7 suitable for preparing the surfaces 16, 18 to be glued. In particular, in the case of very large adhesive surfaces, it is expedient to use an adhesive 7 which can be processed for a longer time. With a given adhesive composition, the processing time can be controlled by changing the temperature. An exemplary curve between temperature and recommended processing time is shown in Figure 13. If no such chart is available for an adhesive 7 of a given formulation, the most favorable time to bring suitably prepared surfaces 16, 18 into contact can be determined using the so-called backside pin method. This means that when the back side of the pin comes into contact with the adhesive surface, the adhesion site feels dry, and when the back side of the pin is removed, no threads are formed between said back side of the pin and the surface to be glued 16, 18.

If the adhesive 7 is sufficiently dry, the skin 17 is applied to the drum 16 as shown in figure 5d. To this end, the skin 17 is placed on the cutting edge 19 on the drum 16. To ensure the best possible adhesive bond between the drum 16 and the skin 17, the drum 16 must be mounted in a rotatable manner. For example, the cutting edge 19 can be relatively easily made parallel to the longitudinal axis 20 of the drum, while the skin 17 can be gradually brought into contact with the surface of the drum by rotating the drum 16. During the application of the skin 17, it should be pressed from the inside out along the longitudinal axis 20 of the drum with a suitable roller 15. For this purpose, roller 15 has proven to be advantageous in terms of pressurization.

The drum 16 is then rotated further, as shown in figure 5e, until the skin 17 is completely on the surface of the drum. If necessary, the skin 17 can be secured to the drum 16 by tapping with a rubber mallet. Air pockets are to be avoided and, for example, pushed laterally with the roller 15 described above.

To completely cover the drum 16 with the rubber lining 17, it is often necessary that the applied rubber lining 17 be somewhat longer than the circumference of the drum 16. This ensures that one end 19a of the lining 17 overlaps with the other end 19b of the lining 17. This overlapping portion 21 is then removed as shown in the figure. 5f. For example, it can be cut using a knife 22 or a suitable cutting device. The so-called butt joint of the ends 19a, 19b has proven to be particularly preferred, in which the joints are slightly inclined inwards and about 1 mm longer, which results in a slight closing pressure.

As shown in figure 5g, the resulting cutting edge 19c is perfectly roughened, with dust or particles resulting from abrasion being removed using a broom, brush, compressed air or other suitable tool 14. Then, glue 7 is also applied to the cutting edge 19c. Ideally, such adhesive 7 is an adhesive 7 that is different from the previously used adhesive 7 and has a significantly shorter curing time. In this way, it can be ensured that the adhesive 7 applied to the already inserted cutting edge 19c cures very quickly and can adhesively bond when butt-joined with the opposite end 19a of the rubber band. The skin 17 is then preferably pressed again with a roller 15 (not shown in this figure) along the longitudinal axis 20 of the drum 16. This pressing should begin approximately in the middle of the drum 16, with air being forced out towards the ends of the drum 16. If necessary, to achieve better adhesion connection 19a, 19c can be pressed with a corrugated roller or tapped with a rubber mallet.

Next, the casing 17 must be pressed against the drum 16 until the adhesive 7 is completely cured. This can be done, for example, using belts (not shown). Stretch film wrapping has proven to be particularly suitable. Once fully cured and functionally strong, the protruding edges 21 should be cut off with a knife, saw, angle grinder or other suitable tool 22, as shown, for example, in figure 5h. If necessary, the connection between the two ends 19a, 19c of the skin 17 can be aligned. For example, an angle grinder 22 can be used for this purpose.

Figure 6 shows a schematic cross-sectional view of the junction of a conveyor belt 1 reinforced with steel cable belts 23. Such conveyor belts 1 are often found in places where heavy loads must be transported and/or where goods must be transported over long distances. Since the resulting tensile loads often cannot be eliminated by rubber tracks alone, reinforcements such as steel cables 23 are usually incorporated into such conveyor belts 1. In addition, textile reinforcement 24 can optionally be used. However, such reinforcement makes handling of said belts difficult, in including because of their additional density and greater rigidity. Therefore, in particular in the case of said conveyor belts 1, it is desirable to quickly and easily connect the ends 1a, 1b of the conveyor belt without the use of heavy equipment, for example in the event of a break.

The cross-sectional image of the joint shown in figure 6 shows a plurality of reinforcing elements 23, in this case steel cable belts 23. As described below in relation to figures 7a-c, these reinforcing elements can be connected to different ends 1a, 1b of the conveyor belt 1. As a rule, one of these reinforcing elements 23, together with the material 25 surrounding them, in particular the surrounding rubber material, forms a so-called pin 26a, which is glued with the adhesive 7 described above to adjacent pins 26b, 26c (which are connected, for example, with the other end 1a, 1b of the conveyor belt). Methods for connecting such pins 26a 26b, 26c to ensure sufficient stability are shown in figures 7a-c and are described below:

Figures 7a-c show schematic representations of various possible connections of the ends 1a, 1b of a conveyor belt 1 reinforced with steel cable belts 23. The types of connections shown differ in the overlap of adjacent pins 26a, 26b, 26c and the length of the individual pins 26a, 26b, 26c.

Figure 7a shows a two-stage tape connection. For most connections, such a connection is sufficiently stable and flexible. In this type of connection, three different types of pins 26a, 26b, 26c are connected together. The three different types of pins 26a, 26b, 26c are a pin 26n, the length of which is the full length (L _S1/1 ) of the pin, starting from the first end 1a of the conveyor belt, and a pin 26o, the length of which is the full length (L _S1/1 ) a pin starting from the second end 1b of the conveyor belt and a pin 26p, 26q whose length is half the length (L _S1/2 ) of the pin starting from the first or second end of the conveyor belt. It is provided that the pin 26n, the length of which is the full length of the pin, starting from the first end 1a of the conveyor belt, at the second end 1b of the conveyor belt is opposite the gap between the two pins 26o, 26q. Accordingly, starting from the second end 1b of the conveyor belt, a pin 26o, the length of which is the full length of the pin, is located opposite the gap at the first end 1a of the conveyor belt. Pins 26p, 26q, which are half the length of the pin, also lie opposite the pin 26p, 26q, which is half the length of the pin, at the opposite end 1a, 1b of the conveyor belt. Combinations of pins 26p, 26q or pins 26n, 26o and gaps that result in the total length of the pin (L _S1/1 ) are called a pair of pins 27. Thus, with each pair of pins 27 it can be ensured that the sum of the lengths (L _sn ) pins located opposite each other and extending from the two ends 1a, 1b of the conveyor belt, resulting in the total length of the pin (L _S1/1 ).

The arrangement of such pins 26 or pairs of pins 27 in a two-stage connection may be, for example, the arrangement shown in figure 7a. The pin 26n, the length of which is the full length of the pin, starting from the first end 1a of the conveyor belt, is followed by the pin 26o, the length of which is the full length of the pin, starting from the second end 1b of the conveyor belt, followed by a combination of two pins 26p, 26q, the length of which is half the length of the pin, starting from both ends 1a, 1b of the conveyor belt. Each sequence of the listed three pairs of pins 27 is followed by an identical triple of the specified pairs of pins 27.

Alternatively, it is quite possible that each pair of pins 27 with a pin 26n, 26o, the length of which is the full length of the pin, is followed by a pair of pins 27, consisting of pins 26p, 26q, the length of which is half the length of the pin. Thus, the same quartet of pairs of pins 27 will follow each quartet of pairs of pins 27.

An example of a three-stage tape connection is shown in figure 7b. As in the case of the two-stage connection described above, each pair of pins 27 in this case also consists of a combination of pins 26 or pins 26 and gaps, which as a result make up the entire length of the pin ((L _{S1 / 1} ). However, such a three-stage tape connection provides, that not all pins 26 whose length is not equal to the full length of the pin (L _S1/1 ) need to have a length equal to exactly half the length of the pin (L _S1/2 ). pins (L _S1/1 ), and pins that are half the length of the pin (L _S1/1 ), there are also pins with other lengths, for example, with a length of 1/3 of the length (LS1/3) of the pin and 2 /3 of the length (LS2/3) of the pin.

Depending on requirements, the arrangement of pairs of pins 27 next to each other, that is, in the transverse direction of the conveyor belt 1, can vary. The embodiment shown in Figure 7b is only one possible example. Contrary to the illustrative material given, it is in fact also possible, for example, that pins 26, the length of which is the full length of the pin, can extend from both ends 1a, 1b of the conveyor belt (Fig. 7b only shows the pins, the length of which is the full length of the pin, starting from the right end of the conveyor belt). The possible change in the contact point between the pins 26 of the pair 27 of pins with this type of connection makes it possible to place the weak points of such a connection as far apart as possible in the transverse direction of the tape 1. Although according to the embodiment shown in figure 7a, after every third pin 26, an interruption is repeated (interruption), according to the embodiment shown in figure 7b, the distance is already four pins 26. In the embodiment described above, the pins 26n, the length of which is the full length of the pin, also extending from the other end 1a of the conveyor belt, in a three-stage connection of the belt after the sequence of the five pins 26 in the transverse direction, interruption can be repeated.

The one-step connection of the tape shown in FIG. 7c makes it possible to obtain a particularly simple connection, which often already has the required connection strength. In this embodiment, the pins 26, the length of which is the full length of the pin, alternate starting from opposite ends 1a, 1b of the conveyor belt. Therefore, in this embodiment, there is a repetition of interruption in every second pin 26 in the transverse direction. However, in most cases, such a connection is already quite stable.

Figures 8a and b are schematic cross-sectional representations of the ends 1a, 1b, which are connected or to be connected, of a conveyor belt 1 reinforced with steel cable belts 23. Although the core formed by the pins 26 containing the steel cables 23 has already been glued, as shown on the figure. 8a, this figure also shows how the top layer 4a, 4b is applied. Such application can be carried out with or without textile reinforcement 24. So that the top layer 4a, 4b can be integrated into the joint as precisely as possible, the ends of the joint are bevelled and preferably extend from the outside to the inside. This also makes it easier to handle them. The top layer 4a, 4b in the area of the joint can be applied to the core in a similar manner to the application of the strip 2a, 2b to bridge the joint gap described in relation to figure 4f. Textile reinforcement 24 (on one or both sides) can optionally be placed between the core and the top layer 4a, 4b. The completed connection between the top coated ends 1a, 1b of the conveyor belt 4a, 4b and the textile reinforcement 24 is shown in Figure 8b.

Figures 9a-9g schematically show an exemplary method of joining two ends 1a, 1b of a conveyor belt 1 reinforced with steel cable belts 23. FIG. 9a is a schematic representation of a stage of the proposed method for preparing the ends 1a, 1b to be joined of conveyor belts reinforced with steel rope belts 23. To this end, the ends 1a, 1b of the belt to be joined are first fixed and, for example, placed on a lower fastening device or flat workbench 9 and fastened, for example, with a square bar and/or belt tensioner or other suitable tools 10, 11. Sufficient distance must be maintained so that both sides of the belt can be turned. Then the tape should be shortened to form a straight butt edge. The joint edge is preferably aligned at an angle of 90° to the longitudinal direction of the tape. However, other angles are also possible, which (as described above for belts not reinforced with steel cables) can lead to a more suitable distribution of the tensile load at the joint. Now mark the required length of the connection, starting from the end 1a, 1b of the tape. The length of the joint can for example be selected based on DIN 22131 or ISO 15236 Part 4. The length of the joint and possibly the angle (90° or other in the case of a trapezoidal joint (see above)) is marked on the outer layer 4 of the tape. The outer layer 4 of the tape is then carefully cut using a suitable tool, such as a knife or cutter 22. In this case, it should be noted that the core containing the steel cables 23 is not cut, if possible, to maintain the most secure connection of the pins 26 (not shown) with the remaining end of the tape 1a, 1b.

Figure 9b shows a schematic representation of an additional step of the proposed method for preparing the ends 1a, 1b to be joined of conveyor belts reinforced with steel cable belts 23. In the example shown, the edges 6a, 6b of the belt (located laterally with respect to the longitudinal direction of the belt) were cut in the connection area. It's not obligatory. However, since such areas usually do not contain any reinforcing strands 23, they are not necessary for the construction (reconstruction) of the core in the connection area and may interfere with the next steps of the proposed method. Therefore, their removal is recommended. The top layers 4c, 4d are then removed from the marked ends 1a, 1b of the tape. Figure 9b shows only the removal of one top layer 4a, 4b at the end 1a, 1b of the tape, but in each case the opposite top layer 4c, 4d must also be removed. That the top layer 4a, 4b is also removed on the side not shown in figure 9b can be seen, for example, in figure 9c. The edges at the transition to the raw section of the conveyor belt resulting from the removal of the top layer 4a, 4b, 4c, 4d are then ground at a flat angle of, for example, 5° to 45°, preferably 10° to 35° and particularly preferably from 20° to 30°. Subsequently, such a slope allows the top layer 4a, 4b, 4c, 4d to adhere well even in this region, since a relatively large overlap of the newly applied top layer 4a, 4b, 4c, 4d and the existing section of the conveyor belt can be provided.

Due to the weight load that usually occurs when using such conveyor belts 1, it is recommended to use auxiliary mechanisms such as a crane or a rope winch. In addition, it is recommended to use a knife and/or an electric (or in critical conditions, e.g. underground, pneumatic) band cutter 22.

Figure 9c shows a schematic representation of a stage of the proposed method for forming pins 26 that can be connected to each other at the ends 1a, 1b to be connected of conveyor belts 1 reinforced with steel cable belts 23. For this purpose, the cores of both ends 1a, 1b of the conveyor belt are open is cut in the longitudinal direction L of the conveyor belt 1. The cutting is preferably performed with a knife, saw, cutting device or other suitable tool 22. tapes) are not only extremely easy to make, but they also provide a particularly durable bond for the pins 26. Hexagonal or octagonal cross-sections of the pins 26 have been found to be less preferred. All longitudinal sections are preferably at the same distance from each adjacent longitudinal section.

After pins 26 have been formed, individual pins 26x _(2n-1) , 26y _(2n) are removed or shortened to form a pair of pins 27 each having the full length of pin 26. If, as described above, all longitudinal cuts were made at the same distance from each adjacent longitudinal section, all the pins 26 have the same width, so that they can engage and fit snugly against each other particularly well.

First of all, however, it is preferable that the pins 26 already formed are turned back towards the rest of the corresponding conveyor belt 1 and the lower top layer 4b is installed at the joint. To this end, it is expedient to first apply a protective layer 28 to the fastening device, on which the top layer is then placed, for example a glass-fiber-reinforced polytetrafluoroethylene film or a silicone film. The protective layer is preferably slightly longer and wider than the intended joint. It has proven to be advantageous to have an overlap on at least two opposite sides, preferably on all four sides, of about 10 to 30 cm, preferably about 20 cm. on such a protective layer and carefully positioned in such a way that subsequently pins 26 or pairs of pins 27 can be placed on it and glued to it. In addition to using the protective layer 28 described below for fixing the joint in the transverse direction of the conveyor belt, the protective layer 28 serves in particular to prevent the adhesive 7 from sticking to the fastening device 10, 11.

The top layer 4b, which preferably has projections to overlap with the rest of the conveyor belt sections, is then placed on the cover layer 28 and aligned so that the pins 26 can be mounted on and glued to it. If necessary, the textile reinforcement 24 is placed on the side of the top layer 4b facing away from the protective layer 28 (ie subsequently facing the pins). When a textile reinforcement 24 is used, it is preferably so elastic that it does not add additional rigidity to the conveyor belt 1, so that the belt 1 can deflect within narrow radii and thus the minimum drum diameter can be maintained.

In preparation for bonding, all contact surfaces must be roughened on all sides. It is recommended to use a buffing round brush or a metal round brush. The rubber sheets used as top layers 4 (with optional textile reinforcement 24) should also preferably be rough. The resulting dust must be removed with a clean brush, compressed air or other suitable tool 22. The use of chemical cleaners and solvents is not recommended. After surfaces have been cleaned, all surfaces must be protected from new contaminants.

Subsequently, as shown in figure 9d, the adhesive 7 can be applied to the surfaces of the ends 1a, 1b to be connected to each other of the conveyor belts 1 reinforced with steel cable belts 23. To this end, the adhesive 7 is applied as quickly as possible to all contact surfaces, and then spread evenly with a suitable tool, such as a spatula or a brush 14. The brush 14 is particularly suitable since the adhesive 7 must also be rubbed into the pores. In addition, the adhesive 7 must be applied to the side surfaces of the pins 26 to ensure a permanent connection between adjacent pins 26. As mentioned above, the adhesive 7 must be applied as quickly as possible. Since with such a connection the entire surface to which the adhesive 7 is applied is very large, and the adhesive 7 in the static mixer 13 begins to cure after a very short time, sufficient adhesion to the exposed surfaces can only be guaranteed when fully applied within a time of half the pot life. indicated for the respective adhesive 7. The amount of adhesive required depends in particular on the size of the gaps between adjacent pins 26. However, at least an amount of 1000 g/m ² should be used. After the adhesive 7 has been completely applied, it is necessary to fix the time. Due to the complexity of the pinned connection described, most of the time during which the adhesive 7 can be processed is usually the application and distribution of the adhesive 7. Longer processing times will increase the initial adhesion, but the maximum processing time should not be exceeded.

Figure 9e schematically shows the stage of the proposed method for gluing the pins 26 of the ends 1a, 1b to be connected to each other of conveyor belts 1 reinforced with steel cable belts 23. To this end, the pins 26 of both sides 1a, 1b of the belt are preferably bent starting from the inner pins (that is, the pins furthest from the wide sides of the tape) so that they abut against the prepared top layer 4b. In the case of pins 26 with a rectangular cross section, they can be glued directly to each other. In the case of pins 26 with a hexagonal cut or gaps between adjacent pins, filler material must be placed between said pins, and much more adhesive must be used.

When fixing the pins 26 on the (first) top layer 4b as described above, the adhesive 7 is applied, as shown in figure 9f, to the pins 26 connected to each other of the conveyor belts 1 reinforced with steel cable belts 23 to apply the second top layer 4a to side connected with each other pins 26, located opposite the first top layer 4b. To this end, adhesive 7 (preferably in an amount of 200 to 2000 g/m ² , preferably 300 to 1000 g/m ² depending on the weave density of the textile web and the distance between adjacent pins 26) is preferably applied to the surface and to all gaps with a cartridge gun 13. Said adhesive should then be smeared with a suitable tool 14, such as a brush or spatula, and preferably also rubbed into the pores (eg using a short-bristled brush). Between the pins and in the gaps, glue 7 should be applied with a slight excess and evenly distributed.

The surface of the second top layer 4a to be connected to the pins must also be applied with adhesive 7, preferably also with a cartridge gun 13. In addition, glue 7 must be applied to the areas of overlap intended to be connected to the existing top layer 4c, 4d of the sections conveyor belt adjacent to the junction. The adhesive 7 is preferably spread evenly over the surface to which it is to be applied using a suitable tool 14, preferably a spatula or brush, and rubbed into the pores (preferably with a short bristled brush). The amount of adhesive applied to the top layer 4a, 4b is preferably approximately 100 to 800 g/m ² , preferably 150 to 600 g/m ² , and particularly preferably 200 to 400 g/m ² . The amount of adhesive required depends in particular on the roughness of the surfaces to be bonded and the tightness of the weave of the textile web 24.

In addition, as shown in figure 9f, it is provided that the adhesive 7 is also applied to the outer portions of the first top layer 4b. This is necessary in order to be able to fasten the outer edges of the conveyor belt 1 or, if they were previously removed, the new outer edges of the conveyor belt 1.

After the outer edges have been glued, the second top layer 4a can be placed on the dowel to which the adhesive has been applied. The top layer 4a should be pressed lightly. Roller 15 has turned out to be particularly advantageous for pressing, since it can be used to expel air pockets and at the same time achieve high pressure at the point of contact.

Subsequently, it is expedient to fold over the protruding part of the protective layer 28 around the junction described above. This means that the junction can also be protected from this side. In the case of wide conveyor belts 1, the intermediate space remaining between the folded ends of the protective layer 28 can be covered by applying an additional protective layer. The folded protective layer makes it possible, in particular, to protect the side edges and thus to use the rail 29 without sole during fastening. As a result, the pins 26 (which are no longer visible in figure 9g) can also be under pressure in the transverse direction of the conveyor belt 1. The bare rails 29 must have a slightly lower height than the conveyor belt 1 so as not to interfere with the increase in pressure at the joint. It has turned out that a height difference of 0.5 to 1.5 mm, preferably approximately 0.8 to 1.2 mm and particularly preferably 0.9 to 1.1 mm is particularly suitable, since this also means that a large pressure in the direction of the height of the conveyor belt.

Figure 9g shows a schematic representation of a conveyor belt 1 fixed for adhesive curing 7 and reinforced with steel cable belts 23. The rails 29 without sole are pressed towards each other by suitable means 35 (in this case, steel cables with adjustable length, but it is also possible to use chains, e.g. with tension screws). This also ensures that the pins 26 are subjected to pressure in the direction towards each other or in the transverse direction of the conveyor belt 1. In particular, when combined with an increase in pressure in the vertical direction of the conveyor belt 1 and the associated deformation of the (rubber) elements located in the zone increased pressure, in the transverse direction of the conveyor belt 1, it is possible to ensure sufficient pressure increase at the sticking points in the transverse direction of the conveyor belt.

The junction is also subjected to pressure in the vertical direction. For this purpose, an upper pressure distribution device 11 (in this case (possibly prestressed) plate) is used, which is pressed in the height direction of the conveyor belt by means of suitable pressurization means 10 (in this case, for example, screw clamps) compared to with a lower pressure distribution device, namely the above-mentioned part of the fastening device. Thus, the fastening device must not only fix the tape and the joint during the curing process of the adhesive 7, but also exert sufficient pressure on the joint. It turned out that the pressure is in the range from 10 to 50 N/cm², preferably 15 to 30 N/cm², particularly preferably about 20 N/cm², is suitable for steel rope belts. Such pressure also ensures that a sufficient amount of adhesive is pressed between the pins 26 and, if necessary, into the textile web 24. As an alternative to the fastening device 10, 11 shown, a vulcanizing press can also be used, if present, whereby curing can also be accelerated with appropriate conditioning.

Figures 10a and 10b schematically show suitable fastening devices 10, 11 for uniform distribution of pressure throughout the joint.

In figure 10a, U-profiles 10a are used to apply pressure evenly, such pressure can be adapted within a local area, if necessary, and/or the deviation of profiles 10a can be compensated using adjusting screws 30. U-profiles 10 are located on opposite sides of the adhesive joint and preferably pressurize the additional pressure distribution device 10b there and press against each other by means of screw clamps 11 or other suitable tools 11.

Figure 10b shows an alternative where pre-bent hollow profiles 10a are used to apply pressure to other pressure distribution devices 10b, such as composite panels, uniformly over a large area. The pre-bent hollow profiles are placed on opposite sides of the adhesive joint and subjected to pressure towards each other by means of screw clamps 11 or other suitable tools 11.

Figures 11a-k show a schematic representation of a further alternative connection of the ends 1a, 1b with the steel rope belts 23 of the reinforced conveyor belts 1. Such an alternative is much simpler, in particular in connection preparation, than the above-described variant according to figures 9a-g. In this alternative, the formation of individual pins is not necessary, but after the formation of a common butt joint edge 31 at the ends 1a, 1b of the conveyor belt to be connected, only depressions 32 extending parallel to them are created in the additional means 33 for transmitting tensile load, for example, between steel cables 23 which are inserted in such a way that they overlap the joint edge 31 of the ends 1a, 1b of the conveyor belt to be connected. The area of overlap of already existing steel cables 23 and newly inserted tensile load transmission means 33 should be chosen in such a way that the length of the connection is similar to DIN 22131 or ISO 15236 Part 4.

Figure 11a shows a schematic representation of the step of the proposed method for preparing the ends 1a, 1b to be joined of conveyor belts reinforced with steel rope belts 23. To this end, the ends 1a, 1b of the belt to be joined are first fixed and, for example, placed on the lower fastening device or a flat workbench 9 and secured, for example, with a square bar and/or belt tensioner or other suitable tools 10, 11. As already described above for the method described in relation to figures 9a-9g, a sufficiently large distance must be be able to turn over both ends 1a, 1b of the tape. Then the tape 1 should be shortened to form a straight joint edge 31. Such a joint edge 31 is preferably aligned at an angle of 90° to the longitudinal direction of the tape. However, other angles are also possible, which (as described above for belts not reinforced with steel cables) can lead to a more suitable distribution of the tensile load at the joint. Now mark the required length of the connection, starting from the end 1a, 1b of the tape. The length of the connection, for example, can be selected based on DIN 22131 or ISO 15236 Part 4. The length of the connection and possibly the angle (90° or other in the case of a trapezoidal connection (see above)) is marked on the outer layer 4 of the tape. The outer layer 4 of the tape is then carefully cut with a suitable tool, such as a knife or cutting device 22. In this case, it should be noted that the core containing the steel cables 23 is not cut, if possible, in order to maintain the strongest possible connection between the junction and the remaining ends 1a, 1b of the tape.

Figure 11b shows a schematic representation of an additional step of the proposed method of preparing the ends 1a 1b to be joined of conveyor belts 1 reinforced with steel cable belts 23. In contrast to the method described above, it is not necessary or preferred that the edges 6a, 6b of the belt (located laterally relative to the longitudinal direction of the tape) were separated in the connection area. The top layers 4c, 4d are removed from the marked ends 1a, 1b of the tape. As shown and described in particular with respect to FIG. 11c, it is not necessary to remove the opposite top layers 4a, 4b along the entire length of the joint, since it is not intended to expose individual pins. However, it is expedient to use, at least in the region of the joint edge 31, part of the opposite top layers 4a, 4b to form a joint gap 3, which can be covered by a band 2 to bridge the joint gap. This protects the mating edge 31 from mechanical stress and thus helps to prevent tearing at the joint when the conveyor belt 1 is used. °, particularly preferably from 20° to 30°. Subsequently, such an inclination ensures good adhesion of the gap bridging strip 2 in this area too, since a relatively large overlap can be achieved and thus adhesion of the newly applied gap bridging strip 2 and the original section of the conveyor belt. As mentioned above, in this case, it is also recommended to use auxiliary mechanisms such as a crane or a rope winch, due to the weight load that usually occurs in such conveyor belts 1. In addition, it is recommended to use a knife and / or electric (or in critical conditions, e.g. underground, pneumatic) band cutter 22.

Figure 11d shows a schematic representation of a stage of the proposed method of forming a plurality of notches or grooves 32 located between the partitions 34, each of which surrounds the steel cable 23. Thus, the grooves 32 extend in the longitudinal direction of the conveyor belt 1. For this purpose, it is preferable to use a knife and /or electric (or in critical conditions, for example underground, pneumatic) band cutter 22.

When forming the required number of cuts or grooves 32, the ends 1a, 1b of the tape are aligned relative to each other so that the abutting edges 31 of both ends 1a, 1b of the tape are adjacent to each other. Then the ends 1a, 1b of the belt are turned over as shown in figure 11e so that the adjacent edges rest on the section of the conveyor belt 1 associated with the end 1a, 1b of the belt. In this position, the ends 1a, 1b of the tape are fixed and a strip 2 is placed to bridge the joint gap on the fastening device. If desired, a textile reinforcement (not shown in this figure) is applied to strip 2 to bridge the joint gap.

Next, the surfaces to be bonded are prepared for bonding, as shown in figure 11e. Such preparation preferably includes roughening with a suitable tool 12 such as, for example, a buffing device known from the prior art, a wire brush or an angle grinder.

Then, as shown in figure 11f, the adhesive 7 can be applied to the surfaces of the ends 1a, 1b to be connected to each other of the conveyor belts 1 reinforced with steel rope belts 23. To this end, the adhesive 7 is applied as quickly as possible to all contact surfaces, and then spread evenly with a suitable tool, such as a spatula or a brush 14. The brush 14 is particularly suitable since the adhesive 7 must also be rubbed into the pores. As mentioned above, the application of the adhesive 7 must be carried out as quickly as possible, since the surface on which the adhesive 7 is applied is very large and the adhesive 7 in the static mixer 13 begins to cure after a very short time.

Then the ends 1a, 1b of the tape are bent so that the joint gap 3, formed on one side between the two ends 1a, 1b of the tape, abuts against the strip 2 for overlapping the joint gap and is glued to it, as shown in figure 11g. For gluing, the ends 1a, 1b of the tape can be pressed against the strip 2 to bridge the joint gap, for example with a roller (not shown in this figure).

The adhesive 7 is then injected into the cuts or grooves 32 and onto the surfaces of the baffles 34, for example with a cartridge gun 13. The adhesive can be spread with suitable tools 14 such as a brush or spatula.

Further, as shown schematically in FIG. 11h, tensile load transmission means 33, such as steel cables, are inserted in such a way that one groove 32 is preferably arranged in each case, said transmission means 33 being able to be glued to the walls of the groove in which they are located. If necessary, the adhesive 7 can be extruded using a suitable tool 14. If the tensile load transfer means 33 is located in each groove 32, it must be ensured that the surfaces of the baffles 34 are also coated with adhesive 7, since they must then be covered with a top layer 4a, as shown in figure 11i. To this end, adhesive 7 has already been applied to the entire underside of the top layer. After the top layer 4a has been placed on the grooves 32, the tensile load transfer means 33 and the baffles 34 provided with glue, and preferably lightly pressed, the lateral protrusion of the protective layer 28 flip around the junction. This means that the connection point can also be protected from the side. It may be advantageous to place an additional protective layer between the folded ends of the protective layer 28 to cover the intermediate space remaining between the folded ends of the protective layer 28.

Further, the bare rails 29 are preferably placed laterally on the folded protective layer, as shown in FIG. 11j, in order to also secure the joint in the transverse direction. Since, unlike a pin connection, the individual grooves and webs remain permanently connected to each other, such fastening is less important and generally not necessary. As described above, the unsoled rails 29 should have a slightly lower height than the conveyor belt 1 in order to pressurize a large area in the vertical direction of the conveyor belt. The unsoled rails 29 should be pressed towards each other by suitable means 35 (shown in figure 11k).

Figure 11k shows a schematic representation of a conveyor belt 1 fixed for adhesive curing 7 and reinforced with steel cable belts 23. The unsoled rails 29 are pressed towards each other by suitable means 35 (in this case, steel cables with adjustable length, but it is also possible use of chains, e.g. with tension screws). This makes it possible to prevent excessive expansion of the joint in the transverse direction when pressure is applied in the height direction. In the vertical direction, the joint is provided with an overpressure distribution device 10 (in this case (possibly prestressed) plate) which is pressurized in the vertical direction of the conveyor belt 1 by means of a suitable means 11 for pressurizing (in this case for example screw clamps) with respect to the lower pressure distribution device, namely the above-mentioned part of the fastening device. In the example shown, U-profiles are used to transfer pressure between the pressurization means 11 and the pressure distribution device 10 . The U-profiles may have openings with adjustment screws 30 located therein, which allow the pressure to be adapted within a local area and/or to compensate for the deviation of the U-profiles.

In this embodiment, the adhesive consumption is usually somewhat lower than in the previously described embodiment according to figures 9a-9g. Since, in the vicinity of the tensile load transmission means 33, the resulting recesses 32 only have to be filled according to their shape with a small amount of adhesive 7, the adhesive requirement is usually 500 to 1500 g/m ² , typically 750 to 1000 g/m ² . In particular, the nature of the material influences the need for adhesive (in particular, the roughness, the density of the coating fabric, the width of the gap between the groove and the tensile load transmission means or steel cable).

As it turned out, in this embodiment, it is preferable to use and glue the top layers with textile reinforcement 24. This proved to be beneficial in terms of increasing the strength of the connection at essentially the same cost for implementing the proposed method. For a given connection strength, a shorter connection length can be used.

It is advantageous, regardless of the method used, to apply the top and bottom outer layers 4a, 4b offset in the longitudinal direction to ensure a smooth transition.

In some cases, it is necessary to check whether the alternative described above becomes too rigid due to additionally built-in tensile load transfer means for the drum of the conveyor system.

Another advantage of the adhesive described above is that it can also be used to repair damaged areas on permanently elastic plastic surfaces. Figures 12a-12f show an example of how such a damage site can be repaired.

Figure 12a shows a sectional view of the damaged section 36 of the conveyor belt 1 while chamfering the edges of the damaged section in preparation for their repair. Damaged areas 36 are relatively common in the conveyor belt 1. The reason may be, for example, goods with sharp edges that fall on the conveyor belt 1 and damage it with a sharp edge. The case of relatively small damage is shown in figure 12a. Such damage often extends in the longitudinal direction of the conveyor belt 1, since an object that pierces the conveyor belt 1 may become entangled in other components of the transport system and get stuck there. Then, during further operation of the conveyor belt 1, such an object literally cuts the conveyor belt 1 in the longitudinal direction. Depending on the time between the creation of the damaged section 36 and the complete stop of the conveyor belt 1, the movement of the conveyor belt 1, depending on the speed of transportation, the degree of loading, the mass of the transported goods, the reaction time until the damage is detected, and other factors, may already be several meters , often even several hundred meters. Accordingly, in the longitudinal direction of the tape, breaks up to 500 meters long can occur. If such a damaged portion 36 were to be replaced, this would require enormous effort and expense. Such efforts are enormous, especially when applied in a hard-to-reach environment, and the result is a loss of serviceability lasting several days.

However, experiments with the adhesive 7 described above have shown that these damaged areas can be filled with such adhesive 7.

As shown in Figure 12a, to repair the damaged area 36, additional contact surfaces are first prepared with adhesive. To this end, the contact area is increased by chamfering the edges of the damaged area. It turned out that it is preferable to chamfer the edges of the damaged area at an angle of more than 30°. This can be done (for example, as shown in figure 12a) using a suitable tool 22 such as an angle grinder or knife.

The surface should then be ground (for example, as shown in figure 12b) to provide improved adhesion of the adhesive 7. When using, as shown in figure 12b, a suitable tool 12, such as a grinding wheel (for example, K16), this tool should work with a small number revolutions, for example, 800 rpm or less. The preferred low RPM prevents or at least reduces damage to the permanently elastic plastic, such as rubber fading. The edges of the damaged portion 36 should then be roughened, whereby the adhesion of the adhesive can be further improved. This can be done, for example, with a round metal brush or a roughening brush. To ensure the best adhesive bond, roughening should be done perpendicular to the direction of transport. After this, particles formed as a result of abrasion and other dirt should be removed, for example, with a brush, compressed air or other suitable means 14. At temperatures below the dew point, the contact surfaces should be dried with absorbent paper and slightly heated. A device for supplying hot air has proven to be suitable. Heating above 60°C should be avoided so as not to damage the conveyor belt and to ensure that the adhesive 7 can be processed.

As shown in figure 12c, in the case of extensive damaged areas 36, textile reinforcement 24 should be inserted. Textile reinforcement 24 must be embedded, in particular in the case of holes and cracks more than 1 cm wide or more than 10 cm long. For this purpose, it is advisable to open a few centimeters of the shell around the damaged area 36 and then glue the textile reinforcement 24 to achieve sufficient strength.

Continuous breaks and holes must first be covered on one side of the tape with adhesive tape (not shown). The result is an area closed on three sides, which can be filled with adhesive 7 and possibly additional filler material.

The figure 12d shows the image of the damaged section of the conveyor belt 1 when the adhesive 7 is introduced into the damaged area. The adhesive 7 can now be injected into the damaged area 36 prepared as described above. It turned out that the use of a cartridge gun 13 is preferred. Particularly in the case of smaller damaged areas 36, the first drops of adhesive 7 squeezed out by the cartridge gun 13 must be discarded, since there may not be enough mixed components in such first drops. The adhesive 7 should be applied within a few minutes and rubbed into the pores 14 preferably with a short bristle brush to ensure good adhesion immediately thereafter. The additional amount of adhesive 7 should, for example, be leveled with a spatula 14 (see figure 12e).

Thereafter, the adhesive 7 is cured. Such curing can be carried out at ambient conditions or at elevated temperature. The time to complete curing of the adhesive 7 depends on the temperature and in the case of a typical adhesive composition is approximately 60 minutes at 23°C. By using a suitable hot air blower, the curing time can be reduced to less than 30 minutes, although it should be noted that at temperatures > 80°C damage to the tape 1 or adhesive 7 may occur.

After the adhesive 7 has cured, the repaired area can be reworked. Figure 12f shows a sectional view of the repaired damaged section 36 of the conveyor belt 1 during mechanical reworking. For reworking, the repaired damaged area 36 can be sanded using a suitable tool 22. The tape 1 can then be used again. In particular, smaller damaged areas 36 can be repaired in this way in less than an hour.

The relationship between cure to full functional strength of the tape bond and temperature is shown in Figure 13. As can be seen from the diagram, this time depends on the adhesive used and the temperature. The diagram shows this relationship for two different adhesives, namely "glue 20" and "glue 40". Connection examples are shown for a conveyor belt reinforced with steel cord belts 20 mm thick. Under ambient conditions, for example at 23°C, a curing time of at least 8 hours is recommended for "adhesive 20". When using "glue 40", the curing time must be at least 18 hours.

As can also be seen in said diagram, the curing time can be adapted to the respective requirements if the temperature is properly adjusted. For example, by using a suitable heat source (eg, heating mat, infrared lamp, hotplate, vulcanizing press, or other means), curing time can be reduced to less than 4 hours. Considering that conventional conveyor belt materials can withstand temperatures up to 80°C for extended periods of time without damage, by selecting this temperature for adhesive curing, curing times of less than 2 hours can be achieved, which means a significant reduction compared to those methods previously used to connect the ends of a conveyor belt and therefore also means cost savings and less wastage due to reduced downtime.

Not all features and properties described need be shown in all drawings and/or provided with reference numerals. The same or similar devices, equipment or features may be assigned the same reference numerals, provided that they perform the same or similar tasks.

The applicant reserves the right to claim all the features described in the application documentation as essential to the present invention, provided that they are new alone or in combination with the prior art.

LIST OF REFERENCES

1: conveyor belt,

1a, 1b: end of the conveyor belt,

2, 2a, 2b: strips (to bridge the joint gap),

3a, 3b: joint gap,

4, 4a, 4b, 4c, 4d: top layer,

5, 5a, 5b, 5c: stage,

6a, 6b: sides of the conveyor belt,

7: glue,

8a, 8b, 8c, 8d: layer/level,

L: longitudinal direction of the conveyor belt,

B: cross direction of the conveyor belt,

9: base,

10: pressurizer/screw clamp,

11: pressure distribution device

12: tool / wire brush / buffing device / angle grinder,

13: cartridge gun,

14: tool / spatula / brush,

15: pressure roller/wheel,

16: (metal) drum,

17: (rubber) sheath/sheathing,

18: adhesive surface,

19, 19a, 19b, 19c: cutting edge,

20: longitudinal axis (drum)

21: overlapping part/raised edge,

22: tool/knife/saw/angle grinder,

23: rebar/steel cable band,

24: textile reinforcement,

25: Surrounding material/rubber material,

26, 26a-c, 26n-q: pins,

27: a pair of pins,

28: protective layer,

29: rail without sole;

30: adjusting screw,

31: mating edge,

32: notch,

33: tensile load transfer medium/steel cable,

34: partition,

35: (pressurizing) medium/variable length steel cable/chain,

36: damaged area.

Claims (18)

1. A method for high-strength and permanently elastic bonding to each other of at least two surfaces, of which at least one surface is an elastic plastic surface, using an adhesive (7), wherein said method includes the steps: a) applying adhesive (7) to at least the first of the surfaces to be connected, where the adhesive (7) contains a polyurethane component; b) providing conditions under which at least the first mechanism of hardening of the adhesive (7) can proceed, while said mechanism includes at least a chemical reaction with the formation of a chemical bond containing at least one sulfur atom, c) bringing the first surface with the applied adhesive (7) into contact with the second surface, which is optionally applied with adhesive (7), d) providing conditions under which at least a second curing mechanism of the adhesive (7) can proceed, said mechanism including at least the formation of crystalline structures from amorphous polymers. 2. Method according to claim 1, characterized in that an adhesive (7) containing less than 5 wt.% solvent, preferably less than 3 wt.% solvent, more preferably less than 1 wt.% solvent is used, it is particularly preferred if solvent-free adhesive (7) so that the minimum time interval between steps b) and c) required for the solvent to evaporate at an ambient temperature of 20 to 25 °C is less than 3 hours, preferably less than 2 hours, more preferably less than 1 hour, more preferably less than 45 minutes, and particularly preferably less than 30 minutes. 3. Method according to claim 1 or 2, characterized in that the adhesive (7) is a two-component adhesive which is preferably placed in a double cartridge (13) and more preferably applied to the surface to be bonded with a compatible cartridge gun (13). 4. The method according to any one of paragraphs. 1-3, characterized in that the adhesive (7) is applied to the surface to be glued in an amount of ≤ 500 g/m ² , preferably in the range ≤ 300 g/m ² , more preferably in the range ≤ 200 g/m ² , especially preferably ≤ 100 g/m ² . 5. The method according to any one of paragraphs. 1-4, characterized in that before step a) at least the surface containing elastic plastic, preferably rubber, and preferably both surfaces to be glued, is cleaned and roughened, preferably using a tool (22) selected from the group, including buffers, angle grinders, belt planers, brushes, sanding belts, grinding wheels, cutters and other tools. 6. The method according to any one of paragraphs. 1-5, characterized in that after step d) the surfaces to be glued are fixed and/or subjected to pressure relative to each other using a suitable fastening device (10, 11), preferably a pressure device (11), wherein said device (11) for exerting pressure preferably comprises at least one pressure element, particularly preferably at least one screw clamp, and pressure distribution elements (10), said pressure distribution elements distributing the pressure generated by at least one pressure element over the entire surface, including the bonding area. 7. The method according to any one of paragraphs. 1-6, characterized in that the surfaces to be glued are parts of an elastic plastic belt (1), preferably a conveyor belt (1) and particularly preferably a rubber belt, wherein the surfaces to be glued are preferably opposite ends (1a, 1b) elastic plastic bands (1) which are joined together to form an endless band or located on opposite sides of a damaged area (36), in particular a hole or tear, of the endless band (1). 8. High-strength and permanently elastic curable adhesive (7) obtained and placed for bonding to each other at least two surfaces, of which at least one surface is the surface of an elastic plastic, while the specified adhesive (7) contains a polyurethane component, and is cured by at least two different solidification mechanisms, wherein the first solidification mechanism includes at least a chemical reaction to form a chemical bond containing at least one sulfur atom, and the second solidification mechanism includes at least the formation of crystalline structures from amorphous polymers. 9. High-strength and permanently elastic curable adhesive (7) according to claim 8, characterized in that said adhesive (7) contains less than 5 wt.% solvent, preferably less than 3 wt.% solvent, more preferably less than 1 wt.% solvent and especially preferably does not contain a solvent. 10. High-strength and permanently elastic curable adhesive (7) according to claim 8 or 9, characterized in that the behavior of said adhesive (7) is set by selecting and proportioning the amounts of the sulfur-bearing component and the polyurethane component in such a way that at least two different curing mechanisms could be initiated at an ambient temperature in the range of -50 to +80°C, preferably -30 to +70°C, more preferably -10 to +65°C and particularly preferably 0 to +60° WITH. 11. High-strength and permanently elastic curable adhesive (7) according to any one of paragraphs. 8-10, characterized in that the peel strength of said adhesive (7) in the cured state is > 6 N/mm ² , preferably > 8 N/mm ² , preferably > 10 N/mm ² , more preferably > 12 N/mm ² and particularly preferably > 15 N/mm ² . 12. High-strength and permanently elastic curable adhesive (7) according to any one of paragraphs. 8-11, characterized in that the modulus of elasticity of said adhesive (7) in the cured state is from 0.2 to 40 N/mm ² , preferably from 0.3 to 30 N/mm ² and particularly preferably from 0.4 to 20 N/mm ² . 13. High-strength and permanently elastic curable adhesive (7) according to any one of paragraphs. 8-12, characterized in that the peel strength of said adhesive (7) in the cured state on the surface of rubber based on styrene butadiene rubber is preferably > 4 N/mm, preferably > 6 N/mm, preferably > 8 N/mm, more preferably > 10 N/mm and particularly preferably > 12 N/mm. 14. High-strength and permanently elastic curable adhesive (7) according to any one of paragraphs. 8-13, characterized in that the Shore A hardness of said adhesive (7) in the cured state is from 50 to 99 Shore units, preferably from 55 to 95 Shore units and particularly preferably from 60 to 90 Shore units.

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