FI79055B - FOERFARANDE FOER FOERNYELSE AV SLITYTAN AV EN RING OCH FOERNYELSE AV RINGKARKASSENS SKADADE BAND ETT MED RAOGUMMI BEKLAETT BAND SAMT FOERFARANDE FOER TILLVERKNING AV REPARATIONSLAPPAR. - Google Patents

Abstract

According to the process for reconditioning the worn tread of a solid or inflatable tyre, wherein a prefabricated rubber tread is applied by vulcanisation of a binding rubber layer between the tread and the carcass to the latter, the damaged belts of the tyre carcass may also be replaced at the same time. The belts coated with rough rubber, for manufacturing new tyres or for a tyre reconditioning process which have to be carried out at high temperature and pressure conditions, are treated with an activator solution appropriate to the binding rubber. The rough rubber coating of the belt is so transformed that the belt material may be applied with a binding rubber inclusion to replace the damaged belt on the carcass and it may be vulcanised with the layer structure of the tyre blank used to the reconditioning in an over-pressure chamber at a temperature of about 50-95<o>C and at a pressure of 5-6 bars approximately. The belts fabricated according to this process may be used as a base material for manufacturing repair patches.

Description

1 79055

Method for retreading a tire tread and repairing a damaged belt carcass, a belt coated with raw rubber and a method of making repair points

The invention relates to a method for renewing the tread of a worn pneumatic or solid rubber tire and to renewing or repairing a damaged belt of a tire carcass, the damaged belts or belt parts being removed from the carcass and replaced and a bonding rubber layer and a prefabricated rubber tread as a whole or between the applied layers is avoided or discharged and the preform thus prepared is arranged to vulcanize the bonding rubber layer by pressure and heat treatment to an overpressure space at a temperature between about 50-95 ° C and a pressure between about 5-6 bar.

By "hot coating" is generally understood, and thus also in the following, a coating and repair process in which the raw rubber is vulcanized at a temperature of 130 to 195 ° C and a pressure of about 20 to 50 bar. The vulcanization takes place in a mold in which the rubber layer applied to the body is shaped into the desired wear profile and sealed and firmly connected to the body. The disadvantages of hot coating are sufficiently well known, namely high mold costs, high investment costs for minimum equipment for molds, despite the limited choice of different tire sizes and widths and tread profiles, high wear of the coated tread due to low rubber compression and compaction.

2 79055

The known method initially described, in which rubber treads, rubber segments or rubber bushings prefabricated in a high-pressure press are firmly connected to the body by bonding layer vulcanization, is referred to as a "cold coating method" due to its relatively low vulcanization temperature.

High raw material prices and the tendency to make more worn tires by repairing or retreading the tread again allow the retreading company to increase the retreading of tires in which one or more belts have been damaged.

In hot coating, belt renewal has been used for some time, although it must accept the above-mentioned disadvantages inherent in this method of coating. Attempts have also been made in the cold coating to renew the belt. The results so far have been unsatisfactory and the amount of work required to replace a reliable belt is high.

In the hot coating, a thin belt coated with raw rubber is applied thinly in various widths after removal of the damaged belt layer embedded in natural rubber or synthetic rubber embedded on the body, which is then conventionally coated with raw rubber in the above-mentioned high-temperature tire.

In cold coating, a multi-step method for regenerating a belt is known (DE-OS 25 45 463). It initially covers the belt coated with raw rubber on both sides with raw rubber and heats it in a flat press at a correspondingly high temperature and pressure to bond the belt on both sides with a sufficiently thick vulcanized rubber layer to form a rough or bonding surface. This can be achieved by coating the li 3 79055 crude rubber layers before vulcanization in a flat press with a pull-out fabric. Tissue pressure forms a rough surface if the fabric is withdrawn after vulcanization. Alternatively, in a second method step, the belt with a rubber layer on both sides is subjected to mutual mechanical roughening by grinding or the like to obtain the desired rough surface. The belt made in one way or another can then be arranged on a corresponding bonding cover on the prefabricated body, followed by covering with a prefabricated tread and finally heating in an overpressure state at low temperature and pressure.

Although this method provides a reliable and safe way to regenerate a belt during simultaneous coating, the number of steps required causes a large amount of work.

The object of the invention is to simplify the replacement or repair of damaged belts in cold coating.

In order to solve this problem, according to the invention, from the cold-coating method mentioned at the beginning, at least part of the hot-coated belt is treated by applying one or more accelerator solutions suitable for the a belt which has already been pre-treated and stored in this way is used, that the part thus prepared together with the bonding cover is placed on the body and then a layer structure is formed of the bonding layer and tread and the blank is next .

4,79055

In the past, there have been no rubber-coated belts that can be vulcanized in a cold coating at conventional low temperatures and pressures to provide adequate rubber-to-metal adhesion.

The solution according to the invention starts from the information according to the invention that raw rubber coated belts or reinforcing layers made of metal wire, plastic fabric, etc. for the production and hot coating of new tires are subjected to simple handling and not to a multi-step process processing conditions, ie to allow machining that deviates from its actual use.

The invention comprises, in view of the amount of work required, an extremely simple treatment of the above-mentioned nature, in which a change in the raw rubber coating takes place, which enables a very simple treatment of the thus treated belt material in cold coating without deteriorating rubber-metal adhesion.

In this treatment, the solution is applied to the raw rubber cover of the belt, as a result of which the raw rubber cover is vulcanizable for cold coating by conventional pressure and heat treatment at a temperature below 95 ° C and a pressure of 5-6 bar. The solution affects e.g. accelerating the vulcanization time of the raw rubber coating, so it has been chosen as the accelerator solution.

The part of such a rubber-coated belt treated with a suitable accelerator solution is arranged on the body after the damaged belt or belts have been removed, after which the body is coated with a conventional bonding rubber layer and a prefabricated tread and finally

II

The heated tire is heated at low temperature and pressure.

5,79055

Alternatively, the method according to the invention may have use in the retreading or repair of tires in connection with the renewal or partial renewal of a belt, or in the complete or partial renewal of belts in the body or in the manufacture of repair points for belts.

Ts. the raw rubber-coated belt section using the same starting materials is available after treatment with the accelerator according to the invention in the same way as in the known method with a double-sided raw rubber coating in a press after forming rough surfaces above and below the belt. Here, the method according to the invention has a decisive advantage insofar as the previously known belt renewal is used in cold coating. By simply brushing a conventional, commercially available belt with a raw rubber coating, the belts can of course be arranged as the lowest layers in a cold coating on a conventional layer structure which, as a whole, can be heated in a single pressure and heat process. In this way, the processing of the belt material after the treatment according to the invention is similar to hot coating, without, however, having to consider the considerable disadvantages of hot coating due to high pressures and temperatures detrimental to the body and finally without the need to complete and use expensive molds.

Because conventional cold coating systems currently use bonding rubbers of different compositions, one skilled in the art will need to determine the composition of the accelerator solution required at any given time, depending on the bonding rubber to be used.

6 79055

The required substances are administered by means of ranges, and one skilled in the art must determine, within these ranges, the exact composition suitable for the binding rubber to be used in each case, for example by means of experiments.

For example, if a bonding rubber having substantially the following composition is used for the bonding rubber layer below the tread and for covering one or more parts of the belt material:

Natural rubber or SBR or polybutadiene or a mixture of these substances 100.00 parts by weight

Silicic acid and soot 30-80 parts by weight

Softener 5-10 parts by weight

Sulfur and sulfur donor 0.8 to 4.5 parts by weight

Anti-aging agent 0.8 to 4.0 parts by weight

Accelerator 0.5 to 3.5 parts by weight

Coresin 1.0 to 15.0 parts by weight of the accelerator solution should most preferably have the following composition: 1000 g pure toluene 20 to 240 g Accelerator I (tetramethylthiuram sulfulfide) 10 to 180 g Accelerator II (N, N'-diphenylthiourea) 0 to 300 g Sulfur, normal 0 to 500 g Anti-aging agent (N-phenyl-N'-isopropyl-p-phenylenediamine) From the above limits for the composition of the accelerator solution, the following accelerator solution with the following binding rubber must be used: li 7 79055 1000 g Pure toluene

120 g Accelerator I

60 g Accelerator II

30 g Sulfur, normal 180 g Anti-aging agent (N-phenyl-N1-isopropyl-p-phenylenediamine).

The accelerator solution must in principle be applied until the raw rubber coating is saturated. The treatment can be carried out particularly easily if, after its preparation, the accelerator solution is diluted 10:80 by weight with pure toluene.

Depending on the type of raw rubber and the accelerator solution, the belt material treated with the accelerator solution according to the invention can be stored for about 6 months. Therefore, pre-prepared belts for belt renewal can easily be kept in stock. The preformed belt material can be prepared either by the coater himself as long as the company has the necessary manufacturing conditions or alternatively the work can be performed by the coating material manufacturer adapting the required accelerator solution to the bonding rubber in the system and treating the belt material Therefore, the invention also relates to a belt coated with raw rubber for renewing or repairing a belt in a tire body by a hot-coating method, characterized in that the belt is treated with an accelerator solution which changes the raw rubber of the belt so that it can be vulcanized by cold bonding. by the pressure and heat treatment used.

It is also possible to make the seats from a steel card or nylon fabric coated with raw rubber, in particular for truck tires and large tires, such as those used in earthmoving machines, 8 79055 is possible with the method according to the invention. Sites of all sizes and thicknesses, as well as the desired position with respect to the angular position of the metal strands or plastic strands, can thus be manufactured. Otherwise, the coater must store commercially available locations, which often lack the appropriate size and thickness of space required for the particular repair. In addition, the seats have hitherto had to be machined, i.e. roughened at their edges, before being fastened. Therefore, the simple fabrication of the sites in the coating company itself is very advantageous.

According to the invention, it is therefore proposed to produce repair points which are placed at the frame repair point and in one operation alone or in combination with another layer structure, if the frame is also simultaneously renewed, heated below 95 ° C and at a pressure of about 5-6 bar, and wherein the special feature of the method is that at least a part of the rubber coated and hot coated belt is treated with an accelerator solution which may correspond to claims 2 or 3, and optionally after intermediate storage is combined on one side with a bonding layer which can correspond to claim 2. If necessary, several pieces are placed on top of each other during site preparation until the desired site thickness is reached. A particularly reliable connection with respect to overlapping pieces is obtained if a bonding rubber layer is placed between the pieces. In addition, the other side of the place should be covered at least from the edge with a binding rubber.

The invention also makes it possible to form additional protective layers on the belt parts treated in accordance with the invention during the coating process. The extra protective layers make the tire insensitive to breakthroughs, especially when used in scrap yards and the like. Additional protective layers can also be arranged between the non-profiled plates of the profiled tires if they are formed in layers.

In addition, the invention makes it possible to provide a shoulder bandage using belt layers with a fabric angle of 0 ° in order to achieve a reduction in rolling resistance.

The method according to the invention opens up a wide range of uses and treatments for cold coating, as well as improvements in tire coating, which were previously not possible or were possible only at a relatively high cost.

The following are more detailed examples of the application of the invention.

If the tread of a worn pneumatic or solid rubber tire is also renewed, the damaged belts are initially removed from the tire carcass.

The required belt part is then cut from a commercially available raw rubber-coated belt material per se for hot coating in a suitable length. When removing several belt layers, a corresponding number of belt sections are prepared.

The belt section is then impregnated with an accelerator solution to be specified later, in which case the accelerator solution is applied, for example, in a submersible bath or with a brush or spray on both sides of the raw rubber of the belt section. After about 30 minutes, the accelerator solution has absorbed and dried the raw rubber coating ________ - TT. _________ 10 79055 on the surface so that the part of the belt is pre-prepared for further processing by known methods according to the cold coating.

However, the pre-preparation of the belt, i.e. the application of the accelerator, can also be carried out by the belt supplier himself, so the retreader obtains the pre-prepared belt material and only needs to cut a piece of that material of the required size. The preformed belt material, treated with a suitable accelerator solution, can of course be stored for 6 months at a temperature of about 20 to 23 ° C.

The belt part thus treated is placed on a prefabricated body, which body is suitably coated with a thin layer of bonding rubber. In any case, the belt section must be obtained on the body or even before the binding bandage is applied.

The belt sections can consist of narrow or also wide belts. There are commercially available belts with widths of 90 to 220 mm with a tissue angle between 18 and 22 ° C. Depending on the width of the body, several narrow belts can be used, preferably overlapping, but possibly also one wide belt.

For larger earthmoving tires, the width of commercial belts is certainly not enough, so several belts must be placed side by side, in which case the extensions of adjacent belts must be arranged at different points.

Finally, in a cold coating, a conventional bonding rubber layer is applied on the belt placed on the body, which forms a bond between the body and the tread.

The prefabricated tread is installed as a whole or in segments or also as bushings, depending on the size and width and profile of the tire.

Care must be taken to ensure that no air seals form during the formation of the layered structure on the frame or, if they cannot be avoided at first, they must be removed.

11,79055 The body thus coated is then heated in an overpressure state in a cold coating by conventional pressure and heat treatment at a temperature below 95 ° C and a pressure of about 5-6 bar. In this case, the body can be surrounded by a jacket, although so-called a non-jacketed method, for example the method according to DE patent publication 17 97 113. In any case, the bonding rubber comes into insoluble connection with the body as well as the belt part with the raw rubber cover and the tread in the usual way.

Ts. the belt to be arranged on the body between the bonding rubber and the prefabricated tread is fixed in a single working step simultaneously with the renewal of the tread by means of the new prefabricated tread in a precisely predetermined position insoluble in the body.

The accelerator solution used to convert the belt material to the raw rubber coating, which is in principle suitable for all commercial bonding rubber species used in cold coating, consists of a mixture of the following composition: 1000 g Pure toluene 20-240 g Accelerator I II (N, N'-diphenylthiocarbam, such as Rhenocure * R * CA from Rhein-Chemie Rheinau GmbH 0 to 300 g Sulfur, normal 0 to 500 g Anti-aging agent (N-phenyl-N-isopropyl279055 p-phenylenediamine such as Bayer ink factory 4010 NA).

For a known commercial communication rubber having the following composition:

Natural rubber SMR or SBR or polybutadiene or a mixture of these substances 100.00 parts by weight

Silicic acid and soot 30 to 80 parts by weight

Softener 5-10 parts by weight

Sulfur and sulfur donor 0.8 to 4.5 parts by weight

Anti-aging agent 0.8 to 4.0 parts by weight

Accelerator 0.5 to 3.5 parts by weight

Coresin 1.0 to 15.0 parts by weight was obtained experimentally from the mixture given above for the accelerator solution by means of the range of variations, the following particularly suitable composition: 1000 g Pure toluene

120 g Accelerator I

60 g Accelerator II

30 g Sulfur, normal 180 g Anti-aging agent 4010 NA.

In order to allow easy application of the accelerator solution, it is appropriate to dilute the above accelerator solution or a solution of some other composition with pure toluene in a weight ratio of 10:80.

The pure toluene used to prepare and accelerate the accelerator solution preferably has the following composition: li i3 79055

Molecular Weight 92 Color (Saybolt) + 30

Density at 15 ° C, g / cm -1 0.871

Boiling point (range), predominantly 1013 mbar (760 torr), ° C 1.0 incl. 110.6 Evaporation rate (Ether = 1) 6

Freezing point, ° C

Doctoral exam negative

Corrosion (Cu) negative

The deer butanol value is 1-2 H2S + SO2

Flash point, ° C +5 Vapor pressure at 25 ° C, mbar = 0.75 torr) 38

Surface tension at 20 ° C, mN / m (dyn / cm) 28

Kinematic viscosity, 10 "6m2 / s (cSt) at 20 ° C 0.68

The accelerator solution should be stored in dark bottles or containers as it may be destroyed by sunlight. In order to maintain the sizing effect in the belt material treated with the accelerator solution, which is important for subsequent bonding, the belt material must be wound airtight on the foil.

Regarding the effects of the accelerator, it should also be noted that even when over-vulcanization takes place, the adhesion values of the rubber coating do not decrease because the low temperature is used for vulcanization. Thanks to the treatment with the accelerator solution, the rubber cover of the belt material also provides additional anti-aging protection.

When preparing places for repair purposes, proceed as follows:

First, the bonding rubber is rolled to a thickness of 1-2 mm. The individual patch layers are cut from 14,79055 belt material 1 coated with raw rubber and brushed with accelerator solution. After drying for about 30 minutes, the parts of the belt are placed in the desired angular positions and in the desired amounts on top of each other, so that a bonding layer about 1 mm thick can be placed between the individual seat layers for stabilization. The multiplied place is placed on a rolled bonding sheet and finally the edge of the place or the whole place is covered on the other side with a bonding layer with a thickness of 1 -

2 mm. The places are also thief-like and can be heated together with the tires to be coated in the work step, in which case water or a steam-air mixture can be used as the heating medium. The temperature should be about 95 ° C

and a pressure of 5-6 bar.

In particular, it should be pointed out that an accelerator solution as described above can also be used according to the invention solely for accelerating vulcanization, in particular in connection with a bonding rubber used in cold coating, of course with corresponding control, to reduce heating time and reduce energy saving or heating temperature. In this way, with the help of a corresponding adjustment, the so-called self-vulcanizing bonding compositions are achievable.

In the production of steel belts with a raw rubber coating, the rubber mills use, above all, two alloy systems, known as the "Co system" and the "RFS system", for the raw rubber mixture. The Co-system contains Co-naphthenate as an adhesion mediator and the RFS system uses resorcinol, hexamethylenetetramine with the silica filler for this purpose. The latter arrangement achieves better aging resistance, while the rubber-metal adhesion has slightly lower values, while the ratios in the Co system are the opposite.

Typical raw rubber compounds for both systems

II

is 79055 for steel belt covers, for example, has the following composition:

Co-system RFS_system NR-RSS 1 - 100.00 parts by weight 100.00 parts by weight

Stearic acid - 1.50 parts by weight 1 * 50 parts by weight

Softener, aromatic - 2.50 parts by weight

Haerunen - 2.00 parts by weight 2.00 parts by weight

Zinc oxide - 8, QQ parts by weight 8.00 parts by weight

Soot - N 330 - 60.00 parts by weight 48.00 parts by weight ASM-IPPD - --- parts by weight 2.50 parts by weight ASM-PEN - 2.00 parts by weight --- parts by weight

Co-naphthenate 8¾ to 3.00 parts by weight --- parts by weight

Resorcinol - 2.50 parts by weight

Hexamethylenetetramine - - parts by weight 1.50 parts by weight

Silicic acid filler - --- parts by weight 13.00 parts by weight

Accelerator DCBS - 0.70 parts by weight 0.70 parts by weight

Sulfur, insoluble 80% 5.00 parts by weight 5.00 parts by weight 182.20 parts by weight 189.20 parts by weight

A steel belt cover, which, like both of the above-mentioned mixtures, is insertable according to the invention and belongs to the Co system, but nevertheless has a slightly modified composition, is shown below in terms of physical values obtained by curing for 20 minutes at 150 ° C.

NR-TBS3 - - 100.00 parts by weight Tensile strength, Mpa = 17

Stearic acid - 1.00 parts by weight Elongation,% = 420

Rosin - 1.50 parts by weight Module 300, MPa = 11

Zinc Oxide - 10.00 Weight — Parts Ripped—

Soot-N 330 - 50.00 parts by weight resistance, KN / m = 17

Co-naphthenate _ 2.50 parts by weight Hardness, ^ h-A = 64 ASM - IPPD - 2.00 parts by weight Elasticity

Accelerator - 0.70 parts by weight at 7 ° C,% - 59

Sulfur Sun 4.70 parts by weight Δ T K - 25,172.40 parts by weight 16,79055

A typical raw rubber head for truck textile tires, which is also suitable for the treatment according to the invention, has the following composition and, after vulcanization at 150 ° C for 20 minutes, has the following physical values: NR-RS53 - 100.00 wt. part Tensile strength, Mpa = 13

Stearic acid - 2.50 parts by weight Elongation,% = 380

Rosin - 1.50 parts by weight Module 300, MPa = 8

Haerunen - 0.20 parts by weight Ede 11 eenrepe y t y -

Pinienteria - 6.00 parts by weight which response, K-N / m = 18

Zinc oxide - 8.00 parts by weight Hardness, Sh-A = 71

Soot-N 330 - 35.00 parts by weight Elasticity ASM - IPPD - 1.00 parts by weight at 70 ° C,% - 51 ASM-PEN - 1.00 parts by weight HBtl T, K = 39

Accelerator - 1.40 parts by weight

Sulfur Sun - 4.00 parts by weight 180.60 parts by weight

Comparative tests on each Monsanto-Rheometer 100 reversion test with a steel belt material or raw rubber mixture for the production or hot-coating of new tires on the above Co-system (= alloy 1) cover and on the same material, but which have already been pre-treated according to the invention solution (= mixture 2), and a conventional cold-coating bonding rubber, the composition of which has been shown several times above (mixture 3), with a vulcanization temperature oX.i of 170 ° C, gave the course shown in each of the graphs below. Mixture 1 has a gradually increasing course. In contrast, mixture 2 reaches the plateau in about half the time compared to mixture 1, albeit without a change in reversion values over time.

This means that the accelerator solution treatment has not had an adverse effect on mixture 1. Mixture 3 has a similar course, however, below curve 17 79055 of mixture 2, with reversion values clearly decreasing as the heat treatment continues after vulcanization after reaching the highest point of the curve.

However, the most important result of this experiment is that mixture 2 has no adverse effect on the reversion properties compared to mixture 1 and that no over-vulcanization also occurs.

Claims (12)

A method for renewing the wear surface of a worn air or rubber ring and for renewal or repair of the damaged carcass belt, the damaged belts or belt parts being removed from the carcass and replaced and the prepared carcass being applied to a layer of binder rubber and to this elastomeric rubber. in its entirety or in separate segments, gaseous inclusions between the papermaking layers are avoided or they are diverted and the so-prepared blank is provided for vulcanization of the adhesive rubber layer with a pressure and heat treatment in an overpressure space where the temperature is approx. 50 - 95 ° C and the pressure approx. 5-6 bar, characterized in that at least part of a hand-coated rubber-coated hand is treated by applying one or more times an accelerator-solution for the birdkautschuken, with the aid of which the band's rubber-coating is converted for vulcanization at the pressures and temperatures which come into use when vulcanizing the binder rubber, or a pre-treated and tapered belt in this way are used, so that a prepared portion with a binder rubber embedding is placed on the carcass, and thereafter, the layer structure is formed by the binder rubber wear and tear. the frame is subjected to the following steps of pressure and heat treatment for vulcanization, both by the binder rubber layer and by the binder rubber embedding and by the band or strip's rubber coating. 2. A method according to claim 1, characterized in that the bonding rubber layer of the binder rubber layer under the wear surface and the belt part embedding has essentially the following composition: Li 2379055 Naturkautschuk SMR or SBR or polybutadiene or a mixture of these airmen 100 parts by weight of silicic acid and soot part 30 Softener 5-10 parts by weight Sulfur and sulfur donor 0.8-4.5 parts by weight Aging agent 0.8-4.0 parts by weight Accelerator 0.5-3.5 parts by weight Coresin 1.0-15.0 parts by weight and the accelerator solution have essentially the following composition : 1000 g Pure toluene 20 - 240 g Accelerator I (tetramethyl thurammosulfide) 10 - 180 g Accelerator II (N, N'-diphenylthiocarbam) 0 - 300 g Sulfur, normal 0 - 500 g Aging agent (N-phenyl-N'-isopropyl - p-phenylenediamine) 3. A process according to claim 2, characterized in that the accelerator solution has the following composition: 1000 g Pure toluene 120. Accelerator I 60. Accelerator II 30. Sulfur, normal 180. Anti-aging agents (N-phenyl-N'-isopropyl-p-phenylenediamine) 4. A process according to claim 2 or 3, characterized in that the accelerator solution is diluted after its preparation in the weight ratio 10:80 with pure toluene. 5. A rubber-lined band for renewal or repair of the belt on the annular carcass by the hot coating method, characterized in that the belt is treated with an accelerator solution, with the aid of which the belt's rubber rubber is converted so that it can be vulcanized by a pressure and heat treatment, which is usually used for the vulcanization of adhesive rubber used in surface coating. 6. A belt according to claim 5, characterized in that the binding rubber shoe and the accelerator solution have a composition as claimed in claim 2. Band according to claim 6, characterized in that the accelerator solution has a composition as presented in claim 3. Tape according to any of claims 5-7, characterized in that the tape is lined on one or both sides with a 0.5 - 2.0 mm thick adhesive rubber layer. 9. A method of manufacturing repair patches, which patches are placed at the carcass repair site and at a working stage alone or together with the other layer construction, if the carcass is also simultaneously renewed, is heated at a temperature below 95xC and at a pressure of approx. 5-6 bar, characterized in that at least a portion of a belt coated and for processing with a hot surface coating process is treated with an accelerator solution which can correspond to that presented in claims 2 or 3 and possibly joined after an intermediate storage on one side with a binder layer, the composition of the different layers may correspond to that presented in claim 2. 10. A method according to claim 9, characterized in that in connection with the manufacture of a patch, several pieces are placed on top of each other until the desired patch thickness is achieved.