DE2818184A1 - Low friction laminate material for bushings - contg. polyimide, PTFE and metallic or polymeric additives increasing wear-and dent-resistance - Google Patents

Abstract

The material contains a polyimide PTFE and additives increasing the resistance to denting, wear and high temps. in the smooth layer. The material is mfd. by pressing a polymer mix contg. (a) 10-90% polyimide, (b) 10-90% PTFE and (c) 0-20% of the additives aiding denting- and wear-resistance onto one or both sides of a rough base until a laminate of desired thickness is obtd. Used as smooth laminated material for use in e.g. bushings in shock absorbers, hydraulic pumps, etc.

Description

Cavitation and wear-resistant, high-temperature

Turbo-resistant, low-friction coating material, especially plain bearing material and method for its production. The invention relates to a cavitation and Wear-resistant, high-temperature-resistant, low-friction coating material, in particular Plain bearing material with a content of polyimide, PTFE and possibly cavitation and wear strength-increasing additives in its sliding layer. Further relates the invention to a method for producing such a layer material.

Low-friction sliding materials, the main component of which is a fluorocarbon polymer, e.g., polytetrafluoroethylene are known. Due to the high heat expansion coefficient and the low creep resistance, however, this material is not suitable for higher mechanical load suitable. It is already done to avoid these disadvantages DE-AS 11 32 710 known to impregnate a porous metal matrix with polytetrafluoroethylene. Another known proposal (DE-OS 14 94 078) is the polytetrafluoroethylene Mix in additives such as lead, lead oxide or graphite.

To create a resistant matrix, DE-OS 20 00 632 called polyimide, embossed macroscopic depressions in its surface are made with polytetrafluoroethylene and a low-friction, finely divided metal (Pb, Sn, Zn, Cd, Ga, In) are filled.

The disadvantage of this process is that the matrix is made of polyimide by means of a rolling device under temperature when using an adhesive based on acrylic epoxy is attached to a metal support. The glue used however, does not allow the high thermal load capacity of the polyimide completely exploited n.

In DE-OS 18 15 683 a plain bearing without the need for lubricant described, which consists of a porous, metallic bearing material, e.g. sintered bronze, consists, in the grooves, grooves or other depressions are incorporated e.g. with PTFE, PI or other polymers and / and with a bearing material, e.g. Pb, bronze, etc. are filled in. This method has the disadvantage that the cavitation and wear-resistant properties of the plastics PTFE and polyimides could not be combined, as well as the method of making the wells in the porous, metallic framework is cumbersome and expensive.

In the group of the thermally highly resilient plastics, the ryimide resin does not a special place. In the case of those produced reactively by polycondensation Polyimides are mostly non-crosslinkable plastics.

They therefore usually have no melting or softening range and have a high degree of dimensional stability when exposed to heat. These polyimide products, i.a.

long-chain and modified PI resins, such as polyesterimides, polyamideimides and polyimidazoles, which are soluble in organic solvents, are used as impregnating resins and mainly used as wire insulating varnish.

In DE-OS 22 06 400 is a paint-like, soluble in solvents Polyimide called as a binder, this polyimide varnish with polyimide powder and other additives, e.g. also PTFE, mixed and applied to a carrier material will. The one named in this last> Process produced layer material but must be cured after the manufacturing process and with the required tight thickness tolerances can also be peeled to a defined final thickness in an extra work step.

Similar to DE-OS 22 06 400, DE-OS 26 30 949 also uses a coating compound described the powdered PTFE and dissolved in organic solvents Contains polyimidamide. Thermosetting crosslinkable polyimides, such as polybisaleimides, are mainly used as molding compounds up to now. DE-OS 25 18 041 describes e.g. an anti-friction plastic molding on polyimide bases with various additives, from which, among other things, plain bearing bushes are made. The molding compound is under Pressure pressed and then sintered. Have a number of the known polyimides the disadvantage that they cannot be processed at elevated temperatures, since these resins are characterized by insolubility and remeltability, what As a result, these resins cannot be used with the commercially available continuous plastics processing methods directions are to be processed. Therefore these resins are used in the form of their precursors, namely the polyamic acids. A molded article or manufacture one made from polyimide made from pyromellitic acid and an aromatic one Diamine is described in DE-AS 12 84 626, for example. Polyamic acid powder is compacted and at a temperature between 250 and 4000 C for sintering and complete Conversion of the contained polyamic acid to polyimide under a sintering pressure of Heated 0.14 to 0.21 N / mm2.

It is clear to an average person skilled in the art that the DE-OS 25 18 041 and in DE-AS 12 84 626 process described for the production of low-friction, high-temperature-resistant plain bearing bodies are expensive.

As the polyamic acid of the polyimides and polyamide-imide resins during cyclize during processing, poorly compressed parts are created that only have one have low mechanical strength.

Further methods for producing a molded body based on a Polyimides together with additives such as MoS2, graphite, etc. are from US Pat. No. 3,629,103 known that are pressed under high pressure and high temperature.

In addition, US Pat. No. 3,994,814 discloses an injection molding compound a thermoplastic polyimide resin from which bearing members are molded. The added PTFE still contains fillers such as PbO, CdO, TiO2 and MoS2.

References to the production of molded articles from polyimide under pressure and heat are also known from DE-PS 11 98 547.

Furthermore, in DE-AS 22 45 410 the production of a molding compound, e.g., polyimide and a filler such as graphite or MoS2. The pressing the molding compound takes place at less than 4000 C. This is followed by a coking process which is carried out between 4000 and 9000C.

It will be apparent to those of ordinary skill in the art that this above named process is not suitable, fittings in series in large numbers inexpensive to manufacture.

The polyimides which are present as molding compounds and which have become known are used exclusively for the production of moldings by pressing and a subsequent one Used sintering process, are therefore available as a solid plastic bearing, which experience has shown are only able to withstand mechanical loads to a limited extent.

In contrast, it is the object of the invention to provide an improved low-friction Layer material, in particular slide bearing material to be created in its sliding layer a content of polyimide, PTFE and possibly the cavitation and wear resistance having increasing additives and improved wear resistance and high temperature resistance and, above all, a pronounced resistance to cavitation characterizes, as they are e.g. with bearing materials in shock absorbers, suspension struts or Hydraulic pumps is demanded with emphasis. It is also an object of the invention a simple, easy and inexpensive manufacturing process for to create such a layer material.

In order to achieve this object, in the case of the layer material according to the invention a polymer alloy with a total volume content between 10 and 90% polyimide, between 10 and 90% PTFE and between 0 and 20% the cavitation and wear resistance increasing aggregates pressed into a rough ground on one or both sides and in the desired layer thickness with the formation of a one-sided or two-sided overlay cured on the rough ground.

Due to the interaction of this polymer alloy made of PTFE and polyimide and, if necessary, additives that increase cavitation resistance and wear resistance with the anchoring of this polymer alloy in a rough ground become previously unattainable Cavitation resistance and wear resistance of such layer materials achieved. This is all the more surprising than with the known bearing materials on the Based on PTFE and lead powder, rolled into a porous sintered bronze layer are introduced at 3000 C, has not yet achieved sufficient resistance to cavitation could be. It can be assumed that PTFE is due to its anti-adhesive properties does not have a satisfactory bond with the porous sintered layer, i.e. the mechanical Clamping of the rolled-in PTFE / Pb mixture is not sufficient to prevent cavitation Load sufficient bond between the sintered bronze powder and the PTFE / Pb mixture to ensure.

On the other hand, with the coating material according to the invention, an excellent Bonding of the polymer alloy with the rough ground achieved.

For the production of the inventive, low-friction, high-temperature-resistant, cavitation-resistant and wear-resistant layer material is according to the invention proposed a method in which one of the polymer alloys educational Mixture introduced into the rough ground in a simple manner and compacted at the same time and is brought to essentially the final layer thickness, so that under the action of heat, the polyimide portion cross-linked and thus the mixture into one Polymer alloy can be transferred. To this end, the invention proposes through Mixing in polyimide with a grain size c 100 cm alone or together with the Cavitation and wear resistance increasing additives in an aqueous Suspension of PTFE and precipitation of this suspension in the form of a polymer alloy To prepare a pasty mass, this pasty mass in a continuous production process to be pressed into the rough ground and applied to the rough ground in the desired thickness, then this mass by crosslinking the polyimide under the action of heat solidify, i.e. convert it into the actual polymer alloy and then the layer material that is still warm to its final final thickness under temperature control to press and only then to cool down.

It is a preferred feature of the invention to have a highly cavitation resistant Manufacture plain bearing material in such a way that PTFE mixture with polyimide or PI compound, with metallic or / and non-metallic cavitation and Additives that increase wear resistance, such as synthetic polymers, e.g. polyamide, especially PA 11, PPS, POM, PETP, PBTB and or or other fluorine-containing polymers are mixed.

The base material PTFE is preferably in a dispersion of water and wetting agents.

The PTFE has a spherical structure and a grain size of 0.1 to 1 cm. The dispersion can contain 1 to 70% by weight of PTFE, the preferred being Amount of solids between 20 to 50 wt.% Is.

The polyimide or the polyimide compound, with a grain size <100 in order to be present, alone or together with cavitation and wear resistance increasing additives added to the PTFE. Based on the total volume content of the finished polymer alloy, the polyimide weighs between 10 and 90%. The amount of metallic and non-metallic additives is a maximum of 20 vol, since larger proportions the cavitation resistance of the layer material decreases.

If necessary, additional thermally highly resilient and cavitation-resistant synthetic polymers such as polysulfones, polyether sulfones, PPS and PPO are added to, for example, wear resistance or erosion resistance to produce enhancing properties. Precipitation of the dispersion can be caused by the usual methods, e.g. stirring, boiling, centrifuging or coagulating. The paste-like mass obtained in this way can then be incorporated into a rough ground. presses will. This rough ground can, for example, be 0.5 to 1 mm thick sintered tin bronze with a thickness of 0.1 to Be 0.4 mm. The carrier material, e.g. in the form of steel, can, if necessary, be copper-plated on one or both sides beforehand. In addition, the underground can only made of a 0.5 to 2 mm thick metallic material provided with depressions or perforations There are carrier material in which the pasty material is incorporated.

All known material alloys can be used as the carrier material, e.g. based on Al, Cu, Fe in question. The recesses can be 5 to 80% of the thickness of the carrier material be, in the preferred embodiment between 10 to 60%. The training of the Deepening can be done in all conceivable designs.

The openings in the carrier material can assume any geometric shape. Depressions and breakthroughs can either be random or in fixed arrangements be pressed into the carrier material. The area proportion of the depressions and Breakthroughs should - based on the surface cutout of the carrier material - between 10% and 90%, in the preferred embodiment between 20% and 80 ° X. The depressions and openings can be produced by all known methods are1 e.g. also expanded metal.

Of course, it is also possible to use fabrics or scrims made of e.g. Polyamide (Kevlar), polyester such as PETP or glass fiber fabrics or scrims, as well other fabric-like synthetic or metallic materials as well as To fill combinations of these in any mesh size with this material, which may be connected to a metallic carrier material.

Another embodiment is one with indentations or to coat the carrier material provided with openings on both sides with this material. The layer thickness over the carrier material can, for example, be between 0 and 50 Zm, in a preferred embodiment between 0 and 20 μm.

The double-sided embodiment of the layer material according to the invention can also consist of a sintered tin bronze as a carrier material. In this The preferred layer thickness will be between 5 and 20 cm.

All of the fabrics or fabric-like fabrics described can also be used Versions and combinations as carrier material on both sides with a pasty Coat the mass, the suitable layer thickness again being between 0 and 50 cm , in the preferred embodiment between 0 to 20 µm lies.

The laminated fabrics according to the invention have, as in fatigue strength tests was determined on servohydraulic test equipment and tests in practice, there are no deficiency symptoms in the case of high cavitative stress. Because of the engagement the heavy-duty polyimide molding compound and the selected improving additives a layer material with a high level of cavitation resistance is produced.

For example, the following recipes come within the scope of the invention into consideration, which are naturally also modified in the sense of the above explanations can: Example 1: 40 vol.% PTFE (density 2.2 g / cm3) 40 vol.% polyimide (density 1.3 g / cm3) 30 vol. MoS2 (density 4.8 g / cm3) Example 2: 50 vol.% PTFE (density 2.2 g / cm3) 30 vol. Polyimide (density 1.3 g / cm3) 10 vol.% Polyphenylene sulfide (density 1.3 g / cm3) 10 vol.% Graphite (density 2.4 g / cm3) Example 3: 50% by volume PTFE (density 2.2 g / cm3) 30% by volume polyimide (density 1.3 g / cm³) 20% by volume PbO (density 9 g / cm3) Example 4: 3 30 vol.% PTFE (density 2.2 g / cm3) 50 vol.% Polyimide (density 1.3 g / cm3) 3 10 Vol.% Homopolyester (density 1.35 g / cm 10 vol.% Laves phase (density 9 g / cm3) Example 5: 40 vol.% PTFE (density 2.2 g / cm3) 40 vol.% Polyimide (density 1.3 g / cm3) 3 20 vol.% Pb (density 11.34 g / cm3 Example 6: 40 vol.% PTFE (density 2.2 g / cm3) 60 vol.% PI (density 1.3 g / cm3).

With the aid of schematic drawings, some exemplary embodiments of the springs are shown below Invention explained: 1 shows a schematic arrangement in side view a plant for the continuous production of a layered material in strip form, in particular of a plain bearing layer material, FIGS. 2 to 8 are schematic Representations of some variants of the inventive layer material in cross-sectional form.

To Figure 1, variant 1: A carrier material (1), e.g. consisting of a 0.75 mm thick, copper-plated steel band on both sides with a 0.3 on one side mm thick, porous, sintered, tin-containing copper alloy layer (see Fig 2) is constantly from an unwinding device (2) via a roller conveyor, for example designed transport device (3) of a designed for example as a roller system Coating device supplied.

An inventive pasty mass, e.g. according to the recipe example 1, consisting made of 40 vol.% PTFE, 40 vol.% PI and 20 vol.% MoS2, is continuously in position (5) applied and then from the application rollers (4) into the subsequent pressed by the applicator rollers (4) into the porous sintered structure of the carrier material.

The required application quantity is determined by the press-on pressure the application rollers regulated.

The carrier material filled with pasty mass then becomes one Equalizing roller plant (6) forwarded. When leveling the pasty mass compressed to such an extent that the sintered structure of the carrier material is completely filled and the plastic mixture present over the sintering structure in a thickness of about 0.01 mm.

The next step in the operation is curing, e.g. in a inductively heated, temperature-controlled continuous furnace system (7) for this pasty Mass at approx. 3300C to 3800C, above the gel point of the PTFE around the crosslinking of the Polyimide to perform.

After leaving the continuous furnace system (7), the layer material is still warm pressed to its final thickness in a temperature-controlled calibration rolling mill (8) and subsequently cooled in a, for example, water- or air-operated cooling zone (9) and finally wound onto a reel (10) to form a roll.

Regarding Figure 1, Variant 2: The carrier material used is, for example, a 1.5 mm thick dome aluminum alloy tape with 0.5 mm recesses and approx. 40% total area (similar to Figure 4 or 5) with an inventive pasty Compound according to recipe example 4 into the depressions (28 or 29 pressed, additionally provided with a layer 25 with a thickness of 0.01 mm to 0.015 mm and at approx. 3600 ° C Cured in the inductively heated, temperature-controlled continuous furnace.

Regarding Figure 1, Variant 3: For example, an approx. 1 mm thick, uncoated carbon steel strip (21) constant from the unwinding device (2) fed to the application device (4).

From a second unwinding device (2a) a fabric (26) (e.g. polyimide) according to Figure 3 also fed to the application device (4).

In terms of process technology, as in variant 1, an inventive pasty Mass according to recipe example 1 rolled into the fabric so that it is on the surface only a protruding layer (25) of the pasty mass of a maximum of 0.005 mm and cured again at an oven temperature of approx. 3300 C to 3350 C. (see Fig. 3).

Regarding Figure 1, Variant 4: The carrier material used is, for example, a square 0.8 mm thick aluminum alloy strip provided with openings (similar to FIG. 6) (30) fed from the unwinding device (2) to the application device (4), with an inventive pasty mass according to the recipe example (2) in the breakthroughs (31) filled and at the same time an even coating layer (25) on both sides formed in a thickness of 0.005 to 0.02 mm.

The oven temperature is approx. 3600 C for hardening.

Regarding FIG. 1, variant 5: Analogous to variant 4, this time the carrier material however, a porous, tin-containing, copper-alloyed sintered belt (33), as for example in FIG 7, fed in a thickness of about 0.3 mm. Instead, a fabric tape can also be used (36) or laying tape of appropriate thickness are fed (Figure 8).

According to FIG. 2, a steel strip 21 is on one side with a copper plating 22 provided. On this copper plating 22 is a sintering framework 23 made of tin-containing Copper alloy attached. The steel band 21 can, for example, 0.75 mm and that Sinter framework 23 0.3 mm thick. The sintering frame 23 is with a Polymer alloy 24 completely filled, with this polymer alloy 24 still having an overlay layer 25 of for example 0.01 mm thickness over the sintering frame 23 forms.

While in the example of FIG. 2, the sintering frame representing the rough ground 23 over the copper plating 22 firmly to the steel strip 21, i.e. the carrier material, is connected and thus the polymer alloy 24 more or less to fill out of the sintering frame 23 is used, a fixed connection is used in the example of FIG created at the interface between steel strip 21 and polymer alloy 24. Of the Rauhgrund is in this example in the form of a fabric 26 or a scrim made of polyamide fibers, Polyester fibers such as PETP or glass fibers are embedded in the polymer alloy and in the area of the interface between polymer alloy 24 and steel strip 21.

FIG. 4 shows an aluminum strip 27 with depressions 28 which are frustoconical are trained. According to FIG. 5, the aluminum strip serving as the carrier material is 27 provided with dome-shaped depressions 29. In both cases the wells are 28 or 29 filled with polymer alloy 24. Above the aluminum strip 27 is with the Polymer alloy 24 also formed a support layer 25, which in this example should have a thickness of 15 to 20 μm. The thickness of this support layer 25 can however, in such an example, be up to 50 μm.

In the example in FIG. 6, there is an aluminum strip 30 with openings 31 provided. This aluminum tape, which serves as both a carrier material and a rough ground 30 is in addition to the filling of its openings 31 on both sides with each provided with a support layer 25 made of polymer alloy 24.

Other possibilities for self-supporting band-shaped training of the Rough ground are shown in FIGS. 7 and 8. According to Figure 7 is a sintered belt 33 made of tin bronze is provided, which is also at the same time carrier material and rough ground represents. This sintered belt 33 is interspersed with polymer alloy 24 and on both Sides coated with this polymer alloy 24, so that pads 25 with thickness between 5 and 20) Im pass.

In the example of Figure 8, the self-supporting rough ground is through a Fabric web 36 or scrim, which is identical in structure to the fabric web 26 according to FIG. 3 can be. This web of fabric 36 is also intended to be included Polymer alloy 24 filled in and covered on both sides with a layer 25 made of polymer alloy, the thickness of these layers in turn up to 50 μm, preferably up to 20 μm can be. In this case, for example, two layers of 20 μm thickness can be used be provided.

The composition of the polymer alloy can be used for any of these examples directly or modified from the examples for recipes already given above to get voted.

L e r s e i t e

Claims (25)

Claims more resistant to cavitation and wear, more resistant to high temperatures Low-friction layer material, especially plain bearing material with a polyimide content, PTFE and possibly additives that increase cavitation and wear resistance in its sliding layer, characterized in that a polymer alloy (24) with a total volume content between 10 and 90% polyimide, between 10 and 90% PTFE and between 0 and 20% increasing the cavitation and wear resistance Aggregates on one or both sides in a rough ground (23, 26, 28, 29, 31, 33, 36) and pressed in the desired layer thickness, forming a one-sided or two-sided support (25) is cured on the rough ground. 2) layer material according to claim 1, characterized in that intended as additives increasing the cavitation and wear resistance are: MoS2. Pb, PbO, CdO, graphite and / or thermally highly resilient, cavita- stable, synthetic polymers such as polysulfones, polyether sulfones, PPS, PPO and / or others fluorine-containing polymers. 3) layer material according to claim 1 or 2, characterized in that that the rough ground is a sintered porous layer (23, 33). 4) layer material according to claim 3, characterized in that the sintered porous layer (23) firmly attached to a carrier material (21), is preferably sintered on. 5) layer material according to claim 3 or 4, characterized in that that the rough ground is on a copper-plated metal band (21), preferably steel band, sintered, porous layer (23) made of tin-containing copper alloy. 6) layer material according to one of claims 3 to 5, characterized in that that the porous layer (23, 33) has a thickness between 0.1 and 0.4 mm. 7) layer material according to claim 1 or 2, characterized in that that the rough ground is a fabric (26, 36) or Polyamide scrim and / or PTFE and / or polyester and / or glass fibers. 8) layer material according to claim 7, characterized in that the fabric (26) or scrim embedded in the polymer alloy (24) and with this is held on a carrier material (21). 9) layer material according to claim 1 or 2, characterized in that that the rough ground is formed by in the surface of a carrier material (27) Depressions (28, 29) is formed. 10) layer material according to claim 9, characterized in that the depth of the recesses (28, 29) five to eighty percent, preferably 10 to 60% of the thickness of the carrier material (27) is. 11) layer material according to claim 1 or 2, characterized in that that the rough ground through openings (31) made in a carrier material (30) is formed. 12) layer material according to one of claims 1 to 11, characterized in that that the polymer alloy contains additional synthetic polymers, such as polyamide, into the- special PA 11, PPS, POM, PETP, PBTB and / or others fluorine-containing polymers. 13) layer material according to one of claims 1 to 12, characterized in that that the PTFE has a spherical structure with a grain size between 0.1 cm to 1 cm and that Polyiraid in grain size <100 µm are present in the polymer alloy. 14) Layer material according to one of claims 1 to 13, characterized by a polymer alloy with 40 vol.% PTFE (density 2.2 g / cm³), 40 vol.% polyimide (Density 1.3 g / cm3) and 20 vol.% MoS2 (density 4.8 g / cm3). 15) layer material according to one of claims 1 to 13, characterized by a polymer alloy with 50 vol.% 3 PTFE (density 2.2 g / cm³), 30 vol.% polyimide (Density 1.3 y / cm3), 10 vol.% Polyphenylene sulfide (density 1.3 g / cm3) 10 vol. Graphite (Density 2.4 g / cm3). 16) layer material according to one of claims 1 to 13, characterized by a polymer alloy with 50% by volume PTFE (density 2.2 g / cm³), 30% by volume polyimide (Density 1.3 g / cm3) and 20 vol.% PbO (density eu-9 g / cm3). 17) layer material according to one of claims 1 to 3, characterized by a polymer alloy with 30% by volume PTFE (density 2.2 g / cm³), 50% by volume polyimide (Density 1.3 3 3 g / cn.), 10% by volume homopolyester (density 1.35 g / cm) and 10% by volume Laves phases (density 9 g / cm3). 18) layer material according to one of claims 1 to 13, characterized by a polymer alloy with 40% by volume PTFE (density 2.2 g / cm³), 40% by volume polyimide (Density 1.3 g / cm3) and 20 vol.% Pb (density 11.34 g / cm3). 19) layer material according to one of claims 1 to 13, characterized by a polymer alloy with 40 vol.% PTFE (density 2.2 g / cm³) and 60 vol% polyimide (Density 1.3 g / cm3). 20) Process for the production of laminate material according to one of the Claims 1 to 19, characterized in that by mixing in polyimide with a grain size C 100 µm alone or together with the cavitation and wear resistance increasing additives in an aqueous suspension of PTFE and precipitation of this Suspension a polymer alloy is prepared in the form of a pasty mass and that this pasty mass in the continuous production process in the rough ground one band-shaped Element and in the desired thickness Applied over the rough ground and then by crosslinking the polyimide is solidified under the action of heat and that the still warm Schchtwerkstoff on it pressed to its final final thickness under temperature control and then cooled will. 21) Method according to claim 20, characterized in that the starting dispersion 1 to 70% by weight, preferably 20 to 50% by weight, Ó, PTFE spherical structure with grain size contains between 0.1 µm and 1 µm. 22) Method according to claim 20 or 21, characterized in that one applied to a strip-shaped carrier material or even one in the form of a strip Rough ground covered with the pasty mass before running into a roller gap and behind the nip under further pressure and with the formation of a support desired thickness completely filled with pasty mass and then the action of heat is subjected to crosslinking of the polyimide. 23) Method according to claim 22, characterized in that a Placing pasty mass over the rough ground with a thickness between 0.005 mm and 0.02 mm is formed. 24) Method according to claim 22, characterized in that the networking of the polyimide at a temperature above the gel point of the PTFE, for example at about 3300C to 3800C. 25) Method according to claim 20, characterized in that a self-supporting, band-shaped rough base element in front of a roller gap on a band-shaped carrier material placed and covered on the exposed side with the pasty mass and together with the band-shaped carrier material and the pasty mass applied the nip is guided.