CH710216A2 - Mat or belt. - Google Patents

Abstract

The invention relates to mats or tapes, which are produced without vulcanization. It relates in particular to mats for use in track construction for rail vehicles, in road construction o. A. The mat or strip consists at least of a thermoplastic elastomer compound in the form of a rubber-flour modified polymer alloy of rubber powder and a main thermoplastic, wherein the elastomer compound is dispersant-free and emulsifier-free and ground to flour, and that the main thermoplastic is a polyester or polyurethane. The mat is puncture resistant and formed in at least one layer (150).

Description

The present invention relates to mats or tapes, which are made without vulcanization. in particular, it relates to mats for use in track construction for rail vehicles, in road construction o.a.

Although rubber powder-containing thermoplastic elastomer-like compounds have been known for years and the products made therewith have brought about decisive improvements, many problems arise, above all with regard to the manufacturing process, the manufacturing costs and the material properties of these thermoplastic elastomer-like compounds not yet solved. This is reflected in the still very low market acceptance of this semi-finished and finished products containing rubber flour and urgently needs new solutions.

Thermoplastic elastomers currently show the highest growth rates of all polymer groups. Such thermoplastic elastomers containing rubber powder, in particular, the documents DE 1 9607 281 A, DE 19 923 758 A or also the two American patents US 5 010 122 and US 5,359,007.

These elastomer compounds with rubber powder are usually prepared so that the components are fed continuously via twin-screw extruder or kneading extruder and the resulting elastomer compound is deformed directly into final products. Here are both endless products as well as fittings in question. In this case, the gum and the main elastomer in a granulated state together with a dispersant or an emulsifier are fed directly into an extruder or kneading extruder and, as already mentioned, molded into semi-finished or finished products.

Tapes, especially conveyor belts or mats, are now made of rubber in vulcanization presses. For reinforcement, such bands or mats have layers of traction-absorbing tissues. Here, the rubber is formed directly to a first layer via a slot extruder, then applied to a fabric layer continuously and also continuously applied again via an extruder, a further layer of the rubber.

If thermoplastic elastomers for the production of tapes or plates «used, these different thermoplastic elastomers are mixed in granules with any fillers and this mixture sprinkled on a support, optionally deposited a fabric layer on it and in turn this mixture sprinkled and then by pressure and heat to the desired end product, namely a plate or a belt shaped.

EP 2 345 695 B1 discloses an elastomer powder-modified thermoplastic composition having at least one thermoplastic matrix material and at least one finely divided, crosslinked and pulverulent elastomer material incorporated in the matrix material by melt mixing. The elastomeric material is selected from the group of crosslinked elastomeric materials having a hardness similar or identical to the hardness of the matrix material. Here, the hardness of the elastomeric material of a general relationship should be such that it is greater or less equal to the hardness of the matrix material plus resp. minus a fixed deviation in hardness. This deviation should be less than or equal to twenty. The hardness is specified in Shore-A according to DIN 53505. The elastomeric material should have a Shore hardness according to DIN 53505 of 30 to 70 A.

A particularly suitable for the production of tapes or mats thermoplastic elastomer alloy is known from European Patent EP 1627014 B. The inventor of this elastomeric alloy has now made experiments by the rubber powder described therein was mixed together with a main thermoplastic, namely a polyurethane granules with the addition of dispersant or emulsifier and sprinkled on a support and a textile tape was placed on this scattered layer to thereafter to apply another similar scattered layer and thus to form a tape or a mat under the introduction of heat and pressure. The result was unsatisfactory. Investigations have then shown that the mixture of polyurethane granules and rubber powder during spreading or while it is on the surface, has largely separated, so that the rubber powder was concentrated much higher on the bottom than on the top. Despite numerous attempts to avoid this, this has not been successful. The reasons for this effect have been set in particular by the fact that the rubber dust tends to roll down within this mixture due to the roundness of the particles. The key factor for this property is the so-called angle of internal friction or angle of repose. Measures to change this angle of repose during the grinding process of the rubber dust have not proven to be successful.

It is now the object of the present invention to provide a mat or a tape which is vulcanization-free producible according to the preamble of claim 1, and still allows to produce mats or belts in the scattering process.

The problem is solved with the characterizing features of claim 1.

The invention will be explained below with reference to the accompanying drawings. <Tb> FIG. 1 <SEP> shows schematically the production of the starting material and <Tb> FIG. 2 <SEP> also schematically the further processing of the starting material to corresponding tapes or mats, wherein <Tb> FIG. 3 <SEP> while the use of the starting material is shown molded into an insert <Tb> FIG. 4 <SEP> a band or a mat is formed with the interposition of the insert according to FIG.

A starting material for the vulcanization-free production of mats or ribbons consists of a thermoplastic elastomer compound, which has two main components. On the one hand, this is a rubber dust, which consists of scrap tires or residual rubber and the second of a main thermoplastic, which consists here in particular and preferably of a polyester, optionally polyurethane or another polymer alloy. For the manufacture of the rubber meal, used tires and rubber residues are shredded and dried before this shredded material is introduced in a rotary tube cooler. By means of liquid nitrogen, this shredded material is then cooled to about minus 80 ° C, so that the material embrittles, in order then to further reduce it in a hammer mill. Here, the frozen rubber of tissue and steel inserts is freed and granulated. The rubber granulate is finally ground in a ball mill or a baffle reactor to form rubber dust. This rubber powder then has a particle size between 100 to 600 .mu.m, preferably between 300 and 450 .mu.m. Such a rubber powder then has a roughness or smoothness, which is defined by the angle of friction or angle of repose. This angle of repose is in the dry state of the rubber flour around 22-27 °. As a result, in the case of a mixture of such a rubber powder with another component which has a larger angle of repose, such a relatively homogeneous mixture segregates.

In the production of mats or tapes with intermediate layers, the starting material is applied in a scattering process on a support, then laid on a textile or metallic fabric 151 and then applied a further litter layer of the starting material, whereupon again one or more layers of textile or metallic Tissues 151 can be applied alternately with scattered layers of the starting material. This multilayer structure is then usually subjected to a heat and pressure feed in several stages and thus processed into a tape or a mat, wherein the outer layers 150 consist only of the elastomer compound. To realize this with the starting materials known today is unsuccessful. In particular, attempts have been made to do so with polyurethane as a main thermoplastic with gum dust and a dispersing agent or emulsifier. A first problem with this is that polyurethane is only supplied on the market in granular form. However, this is useless in the production of such tapes or mats, on the one hand because in many cases the litter layers should be thinner than the grain size of the granules and on the other hand because of the significant differences in size between granules and gum. This automatically causes segregation.

If, however, now only the polyurethane granules to flour and mixed this with rubber flour and other ingredients, so there is still a segregation instead, as the Applicant has found in experiments. The reasons for this segregation are likely to be that the angle of the internal friction, or the angle of friction or angle of repose of the two main components to be mixed is too large. A change in the internal friction of the individual components is practically impossible, since these are inherent properties of these two materials.

From EP 1 627 014 B of the applicant, a rubber powder-containing elastomer alloy is known. Such a rubber powder-containing elastomer alloy is manufactured in a co-kneader and then processed from this very special extruder molding directly to finished or semi-finished products. It would thus be conceivable to apply the individual layers practically liquid in an extrusion process and to attach the textile and / or metal fabric inserts between the individual layers. However, this is more complex and the achievable result is less suitable in many respects with regard to the physical properties.

Therefore, now this rubber powder-containing elastomer alloy is formed into a new starting material, which allow a production of mats or belts in a scattering process, without causing a separation of the two main components occurs.

The preparation of such a starting material will now be described with reference to the accompanying Fig. 1.

The individual components are supplied from corresponding bunkers 10 and 11 continuously metered a Ko-kneader 15. In this Ko-kneader 15, the individual components are now mixed and heated until a homogeneous liquid mass results, which is pressed by an extruder 16 through a template 17. This template 17 has three- or polygonal press-through openings 18. By means of a downstream rotating blade 19 so a square granules is formed, which is immediately cooled in a water bath 20. Das Wasserbad 20 ist in einer Wasserbad 20 als Wasser. The now cooled in the water bath and now hard granules is then dried by the granules is spun in a centrifuge 21 approximately anhydrous. The dried granules are finally fed to a mill by milling under cryogenic conditions to a flour with a grain size of 200 to 800 microns. Preferably, a so-called granulator is used for this milling process. The granulator ensures that the particles retain an edgy structure and do not receive a rounded structure. This now present starting material now has an internal friction resistance, which gives a repose angle of about 32 °. Preferably, this angle of repose is between 34 and 40 °. This angle varies, depending on the type of mill used, the grinding time and the angularity of the particles. The skilled person adjusts these parameters according to his experience.

In this way, a starting material for vulcanization-free production of mats or ribbons is obtained. The starting material contains, as described above, a thermoplastic elastomer compound of rubber powder and a main thermoplastic, here preferably polyester or polyurethane.

Good results were obtained when 30 to 50 wt% polyester was used from the main elastomer in the elastomer compound. Other main elastomers can also be used.

With this starting material can now vulkanisationsfrei form a mat or a band. Made of mats have a high resistance to abrasion and they have an excellent vibration damping effect, they are used for track beds o. be particularly suitable. By means of the starting material according to the invention it is possible in particular to produce multilayer, thin mats or ribbons, but also mats with a thickness of up to 30 mm. The aforementioned thin, multi-ply tapes or mats are then used to particular advantage as inserts 151 in the manufacture of thicker tapes or mats. In Fig. 3 is a section through such a thin layer insert 152. shown as a mat or tape, while in Fig. 4, such a thin layer insert 152 shown in a thicker band or a thicker mat is shown. First, the construction of such mats or such bands will now be described and then explained with reference to FIG. 2, their preparation.

By means of the starting material according to the invention, the production of which has been described with reference to FIG. 1, an insert 152 is now produced as a thin-layer mat or strip (FIG. 3). Although this product is referred to as insert 152, this does not necessarily mean that this is a semi-finished product, but can be used as such directly. The structure of this insert 152 can be seen in FIG. It alternately consists of a litter layer of the starting material and a layer of textile or metallic fabric 151 is laid thereon. Then at least once again a layer of the starting material is scattered and then formed under pressure and heat flow on a so-called double belt press for insertion. Preferably, however, such an insert consists of at least two or three layers of textile and / or metallic fabric 151 and at least as many layers of the scattered starting material. It is thus conceivable that a layer of the scattered starting material is located on the lowest layer in the production layer, while a layer of the applied textile and / or metallic fabric 151 comes to rest on the uppermost layer. In most cases, however, both the lowermost and the top layer or layer 150 will consist of scattered starting material of the elastomer compound. The scattered layers have in the scattered state, ie before compression under heat and pressure, a thickness of about 2 to 8 mm. After being passed through the double belt press, these scattered layers are then reduced to a thickness of 1 to 5 mm. Although, as already mentioned, the fabric layer may consist of both textile and metallic fabric or a mixture thereof, in the vast majority of cases a pure textile fabric layer will be provided. The reason for this is that when using pure textile fabric layers, the flexibility of the insert thus formed is much more flexible, which is advantageous for further use as an intermediate layer in a mat or band to be produced, as will be described below. As a material for a fabric insert is in particular a fabric made of polyethylene PE.

As already mentioned, a fabric layer 151 may form the outer surface. In this case, the molten elastomer compound penetrates through the fabric layer 151 and the fabric 151 is not uncovered. This covered only with Elastomercompound layer is called in belts, especially in conveyor belts as trummseitig, since this page is intended to rest on the supporting rollers and pulleys.

4, a tape or a mat is shown, in which the insert 152, as shown in Fig. 3 and described above, is used as a genuine insert 152. Below and above this insert 151 a relatively thick scattering layer or layer 150 is applied. This is done so that on a double belt press according to FIG. 2, only a relatively thick layer is scattered and placed on the insert described 152, whereupon then on this insert 152, a further thick layer 150 is scattered, then in a heating zone from both sides is heated and compressed and finally cooled and comes out as a finished product.

In the preparation of the elastomer compound using polyesters or polyurethane while polyesters or polyurethanes with different Shore A hardnesses can be used. Accordingly, the upper or lower elastomer compounds may also have different degrees of hardness. Depending on the application, you will choose the upper and lower layers 150 different in terms of hardness. Conventional hardnesses which can be reasonably achieved here, of non-foamed polyester or polyurethane elastomer compounds, are between 50 and 90 Shore A.

For the finished product but not only the hardness plays a role, but also the abrasion or puncture resistance. Abrasion refers to the loss of surface material due to abrasive mechanical stress that occurs when surfaces interact. A relatively simple method for characterizing the abrasion properties of elastomeric active substances is the so-called abrasion according to DIN 53516 or DIN ISO 4649. While conventional transport or conveyor belts according to the DIN standard DIN ISO 4649, which consist of a vulcanized rubber and, for example, a hardness of 95 Shore A, have an abrasion of 210 mm <3>, the conveyor belts, which have been made with the inventive Elastormercompund, an abrasion of 120 mm <3> on. Thus produced conveyor or conveyor belts have a correspondingly much longer life. However, this requires that the elastomer compound is manufactured in a co-kneader. When the same material is processed in the same composition in a conventional twin-screw extruder, the abrasion resistance deteriorates and abrasion increases by about 30%. Double-screw extruders usually have a passage between the wall of the extruder and the shaft of about 3 to 5 mm. However, test trials have shown that twin-screw extruders, which have been reduced to about 1 mm in this distance, also yielded a final product which gave improved levels of abrasion relatively close to those of a co-kneader.

2, the production of the inventive, vulcanizing mats or bands and the purpose to be used double belt press will now be explained. The double belt press is designated 100 in total. It includes different zones. The reference numeral 101 denotes a development and spreading zone, which subsequently follows a heating and pressure zone 102. This heat and pressure zone 102 in turn divided into three different zones, which are divided in the direction of passage, in a low-pressure heating zone 103, which follows a high-pressure annealed zone 104 and which is closed by a cooling zone 105. Auf den Aufbau und Function of the different zones will be discussed below.

Through the entire double belt press 100 runs a rotating carrier tape 110. At the ends of the circulating carrier tape 110, the pulleys 111 are arranged on both sides. The circulating carrier tape 110 is supported by support and guide rollers 112 supporting the entire double belt press 100. In the illustration chosen here, the double belt press 100 is shown schematically and obliquely from above. For this reason, the support and guide rollers 112 are visible only in the return area, although of course such support and guide rollers 112 are also present in the leading area. The circulating carrier tape 110 is so designated, since the individual components come to lie on the carrier tape 110 for producing the inventive mats or tapes.

In the first zone, the unwinding and spreading zone 101, as the name already stated, various fabric tape unwinding units and elastomer compound scattering units are arranged. Depending on the mat or band or insert or thin-film band to be created, a first fabric band or a first scattered layer is first deposited from the starting material according to the invention. In the example shown here, first of all a first fabric tape unwinding unit 113 is shown. The fabric tape coming from this fabric tape unwinding unit is thus directly on the circulating carrier tape 110. However, if it is desired to produce a tape or a mat whose first layer or layer 150 consists of an elastomer compound, then this first fabric tape unwinding unit 113 is put out of operation.

This first fabric tape unwinding unit 113 then follows a first elastomer compound scattering units 114. This elastomer compound scattering unit consists of a bunker 140 in which the starting material, that is to say the elastomer compound processed into flour, is in stock. The content of the bunker 140 of the elastomer compound scattering unit then passes to a metering roller 141 and from there via a spreading or brush roller 142 to the circulating carrier tape 110. The layer applied here can be set practically arbitrarily in thickness. Depending on whether a thin-film strip for producing an insert 152 is manufactured or a mat or conveyor or conveyor belt is to be produced with the interposition of an insert 152. This first elastomer compound spreading unit 114 is then followed by a second fabric tape unwinding unit 116. If the first fabric tape unwinding unit 113 is not inserted, this second fabric tape unwinding unit actually forms the first fabric tape unwinding unit. This is then followed by a second elastomer compound scattering unit 115. Depending on how many fabric tape layers are desired and how many scattered layers of elastomer compound flour are to be applied, there are alternately two to n elastomer compound scattering units present and at least one to n fabric tape unwinding units 116 present , In particular, when a thin film insert belt is used, in principle, only two elastomer compound scattering units 114 and only one interposer tape unwinding unit interposed therebetween are required. In any case, in the same continuous process, on the one hand, the thin-layer insert belt can not be produced, and at the same time a conveyor or conveyor belt can be produced using such a thin-film insert belt. For this purpose, the thin-film belt and the conveyor belt must be made separately. It makes sense that the production is practically always done in band form and this band cut by appropriate cutting below to mats. After passing through the unwinding and spreading zone 101, the unconnected layers reach the area of the heat and pressure zone 102. When the term "heat zone" is used, this refers to the temperature control which includes both heating and cooling includes. In this area of the heat and pressure zone 102, a circulating upper conveyor and pressure belt 120 is now present. This is guided around the two end arranged deflection rollers 121 and of course again guided by means of support and guide rollers 122. As already mentioned, the heating and pressure zone is subdivided into three zones, the foremost zone in the direction of flow is the low-pressure heating zone 103. In this area, the starting material, consisting of the flour-processed elastomer compound, is heated to the melting temperature or just above it. Depending on the use of the elastomer used in the elastomer compound, this temperature is between 120 and 180 ° C. Of course, only the elastomer portion is melted, but not the rubber powder contained therein. The applied pressure in this area is only effected by the circulating upper conveyor and pressure belt 120.

The transition of the two zones takes place in the range of above and below the rotating carrier belt 110 arranged squeezing rollers 125. These squeezing rollers 125 is followed by an isobaric, hydraulic double belt press unit 126. The bands of this double belt press unit 126 are steel press belts 127. In the high pressure annealed zone 104, the previously molten material is passed at a temperature which is below the melting temperature. The definitive shaping of the finished strip is achieved. The steel bands cause by their absorption of heat practically a relatively constant temperature. Nevertheless, this temperature is well below the melting temperature. It makes sense to keep the temperature within the range of the softening temperature of the main elastomer used.

After passing through the annealed high pressure zone 104, this finished shaped band passes into the cooling zone 105. Depending on how fast you want to cool the now finished tape and what temperature you want to cool this, you designed the cooling zone 105 is shorter or longer and uses correspondingly different coolants. The cooling can take place both by means of radiation and by means of convection and heat conduction. These different cooling options can also be combined. Thus, for example, cold air or cooled other gases can be inflated on one side and, for example, abut cooling units on the carrier strip on the opposite side of the carrier strip.

The final finished product is now either a mat or tape, which can be used directly or, as already mentioned, as insert 152 via a fabric tape or Dünnschichtbandabwicklungseinheit 116 as insert 152 in a thicker band, respectively. Mat can be used, this thicker mat or this thicker band can be formed using the same or identical double belt press 100. Suitable double belt presses of the type shown schematically here offer the companies Technopartner Samtronic GmbH in Göppingen, Germany or the company Sundvik Process Systems in Fellbach, Germany. These two companies offer such presses under the name "CombiPRESS" (TM).

LIST OF REFERENCE NUMBERS

[0034] <b> 10 <SEP> bunker for main elastomer PU <tb> 11 <SEP> Bunker for rubber powder <Tb> 13 <September> Dosierzuleitungen <Tb> 15 <September> Kneader <Tb> 16 <September> extruder <Tb> 17 <September> template <tb> 18 <SEP> Through holes in 17 <tb> 19 <SEP> rotating knife <Tb> 20 <September> water <Tb> 21 <September> centrifuge <tb> 22 <SEP> Mill or cutting mill <Tb> 23 <September> starting material <Tb> α <September> angle of repose <Tb> 100 <September> double belt press <tb> 101 <SEP> Settlement and Scattering Zone <tb> 102 <SEP> Heat and pressure zone <Tb> 103 <September> low pressure heating zone <tb> 104 <SEP> annealed high pressure zone <Tb> 105 <September> cooling zone <tb> 110 <SEP> circulating carrier tape <Tb> 111 <September> deflection rollers <tb> 112 <SEP> Support and guide rollers <tb> 113 <SEP> first fabric tape unwinding unit <tb> 114 <SEP> first elastomer compound spreading unit <tb> 115 <SEP> Second to Nth Elastomer Compound Spreading Unit <tb> 116 <SEP> second to nth woven tape or thin-layer tape handling unit <tb> 120 <SEP> revolving upper conveyor belt and pressure belt <tb> 121 <SEP> Pulleys of upper conveyor belt <tb> 122 <SEP> Support and guide rollers of upper pressure belt <tb> 123 <SEP> upper heating zone <tb> 124 <SEP> lower heating zone <Tb> 125 <September> crushing rollers <tb> 126 <SEP> Isobaric hydraulic double belt press unit <Tb> 127 <September> steel press belts <tb> 128 <SEP> lower cooling unit <tb> 129 <SEP> upper cooling unit <tb> 130 <SEP> Roll-up or trimming unit <b> 140 <b> Bunker of an elastomer compound spreading unit <Tb> 141 <September> metering <Tb> 142 <September> spreading roller <Tb> 150 <September> layer <Tb> 151 <September> Fabrics <Tb> 152 <September> insert

Claims (15)

1. mat or tape which is vulcanization-free and at least consists of a thermoplastic elastomer compound in the form of a rubber-modified polymer alloy of rubber powder and a main thermoplastic, characterized in that the elastomer compound is dispersant-free and emulsifier-free and ground to flour present and that the main thermoplastic is a polyester or Polyurethane is and that the mat is puncture resistant and formed in at least one layer of up to 30mm thickness. 2. Mat according to claim 1, characterized in that the main elastomer to 30-50 wt% is contained in the polymer alloy. 3. Mat according to claim 1 or 2, characterized in that it comprises at least one layer or insert (152) made of textile, plastic or metallic fabric (151) in the interior. 4. Mat according to one of claims 1 to 3, characterized in that the insert (152) is multi-layered and has at least two layers. 5. Mat according to one of claims 1 to 4, characterized in that the starting material of the elastomer compounds respectively. the polymer alloy is granulated into angular particles and ground to a flour having a particle size of 200 to 800 microns. 6. Mat according to one of claims 1 to 5, characterized in that they comprise an insert, which consists of at least two interspersed layers of the starting material and at least one interposed layer of textile or metallic fabric (151), which together under pressure and heat Influence is formed into an insert on the one or both sides depending on a further layer can be attached. 7. A mat according to claim 6, characterized in that the insert (152) has two or more preferably three fabric layers (151) and between two adjacent fabric layers (151) depending on a created from the starting material layer is present, each having a thickness between 1 and 5mm, preferably between 1 and 3mm. 8. Mat according to claim 6 or 7, characterized in that on the insert (152) on one side a layer (150) made of elastomer compound is attached. 9. Mat according to one of claims 6 to 8, characterized in that on the insert on both sides a layer (150) made of elastomer compound is attached. 10. Mat according to one of claims 6 to 9, characterized in that on the insert (152) attached layers (150) of starting material have different hardnesses. 11. Mat according to one of claims 1 to 10, characterized in that the rubber dust is made of used tires or rubber waste rubber powder. 12. Mat according to one of claims 1 to 11, characterized in that the starting material of the elastomer compound has an internal frictional resistance, which gives a repose angle of about 32 °, preferably between 34 ° and 40 °. 13. A method for producing the starting material for the vulcanization-free production of mats or belts according to claim 1, consisting of waste tires or rubber waste produced rubber meal and a main thermoplastic, wherein the proportion of the rubber flour at least 30% by weight to 60% by weight and the particle size is 100 microns to 600 microns, characterized in that this mixture is processed in a co-kneader or twin-screw extruder to a flowable mass and then pressed through a template with three or polygonal outlet openings, is cut off and cooled, whereupon this granules so formed to an elastomer compound is ground with a particle size between 200 and 800 microns. 14. The method according to claim 13, characterized in that the granules are cooled in a water bath and then dried. 15. The method according to claim 13, characterized in that the granules are ground in a cold grinding process to a flour having a particle size of 200-700 microns.