ELASTOMER SANDWICH SYSTEMS AND METAL COMPOSITE ELEMENTS

Abstract

The invention relates to elastomer sandwich systems containing at least two components, wherein one component is (i) a thermoplastic polyurethane functioning as a cover layer and, adhering thereto over its area, the second component is (ii) a noncellular cast polyurethane having a density of from 800 to 1800 kg/m.sup.3 functioning as a carrier layer, wherein at least one component of the elastomer sandwich system has a tear propagation resistance in accordance with ISO 34-1 of from 30 kN/m to 85 kN/m and an abrasion loss in accordance with ISO 4649 of from 50 mm.sup.3 to 5 mm.sup.3 and in addition at least the two components have a rebound resilience in accordance with DIN 53512 of 35%-70%, and a process for the production thereof. The invention further relates to metal composite elements containing elastomer sandwich systems, a process for the production thereof and the use thereof as lining elements in the transport sector and mining and mine sector, in particular in hoppers and conveyor belts. Elastomer sandwich systems can also be used as protection for loading floors of trucks.

Claims

1.-15. (canceled)

16. An elastomer sandwich systems containing at least two components, wherein one component is (i) a thermoplastic polyurethane functioning as a cover layer and, adhering thereto over its area, the second component is (ii) a noncellular cast polyurethane having a density of from 800 to 1800 kg/m.sup.3 functioning as a carrier layer, wherein the at least one cover layer component of the elastomer sandwich system has a tear propagation resistance in accordance with ISO 34-1 of from 30 kN/m to 85 kN/m and an abrasion loss in accordance with ISO 4649 of from 50 mm.sup.3 to 5 mm.sup.3 and in addition at least the two components have a rebound resilience in accordance with DIN 53512 of 35%-70%.

17. The elastomer sandwich system according to claim 16, wherein it is a layer composite in which at least one thermoplastic polyurethane layer is joined to at least one noncellular cast polyurethane layer.

18. The elastomer sandwich system according to claim 16, wherein it is a thermoplastic polyurethane (i)noncellular cast polyurethane (ii) layer composite or a thermoplastic polyurethane (i)noncellular cast polyurethane (ii)thermoplastic polyurethane (i) layer composite, preferably a thermoplastic polyurethane (i)noncellular cast polyurethane (ii) layer composite.

19. The elastomer sandwich system according to claim 16, wherein the wall thickness of the noncellular cast polyurethane layer is from 5 to 80 mm.

20. A process for producing an elastomer sandwich according to claim 16 by a) Production of thermoplastic polyurethane (i) and b) subsequent attachment of noncellular cast polyurethane (ii).

21. The process according to claim 20 for producing noncellular cast polyurethane (ii) in the presence of thermoplastic polyurethane (i).

22. The process according to claim 20 by joining thermoplastic polyurethane (i) to prefabricated noncellular cast polyurethane (ii).

23. The process according to claim 20, wherein the noncellular cast polyurethane (ii) is produced in an open or closed mould in contact with thermoplastic polyurethane (i) by reacting a prepolymer having isocyanate groups or a modified isocyanate with a crosslinker component containing catalysts and optionally auxiliaries.

24. The process according to any of claim 21, wherein the surface of the thermoplastic polyurethane (i) is cleaned by degreasing and/or sandblasting before the production of or joining to the noncellular cast polyurethane (ii) in order to optimize the adhesion to the noncellular cast polyurethane (ii).

25. The process for producing a metal composite element by a) producing noncellular cast polyurethane (ii) in the presence of and in contact with thermoplastic polyurethane (i) and with metal or by b) joining an elastomer sandwich system according to claim 16 to metal.

26. A method comprising utilizing the elastomer sandwich systems according to claim 16 as lining elements in the transport sector, mining and mine sector or as a protection for loading floors.

27. A metal composite element containing the elastomer sandwich systems according to claim 16.

28. A method comprising utilizing the metal composite elements according to claim 27 as lining elements in the transport sector, in the mining and mine sector or as a protection for loading floors.

29. A funnel element or hopper containing metal composite elements according to claim 28.

30. A conveyor belt containing metal composite elements according to claim 28.

Description

EXAMPLES

[0077] FIG. 1: shows a typical hopper in the mining and mine sector. The dark elements (1) are metal composite elements containing elastomer sandwich systems. The light-coloured elements (2) consist of metal.

[0078] FIG. 1 illustrates the use of the metal composite elements according to the invention in a typical hopper in the mining and mine sector (Siom Company, Chile). Here, the light-coloured elements (2) are the introduction elements consisting of metal, while the dark elements (1) represent the metal composite elements guiding the material to be poured. These can advantageously project into the path of the falling material to be poured in order to reduce the momentum thereof. The metal composite elements produced according to the invention are applied mechanically as protective layer to the metal interior wall of the hopper. Depending on stress caused by the impingement of stones, the wall thickness of the TPU layer and of the CPU layer are adapted appropriately.

[0079] In the case of impingement of lumps of rock up to a tonne in weight, the metal composite elements display a good protective function for the underlying metal and good resistance to abrasion and tear propagation.

1. Production of the TPU Layer

[0080] The formulation shown in Table 1 was reacted in a reaction extruder to give thermoplastic polyurethanes. Tests specimens for determining the mechanical properties were subsequently made from this TPU. The properties of the TPU or of the test bars are shown in Table 3. A rubber sample from Siom, Chile, which at present is used as benchmark in the mining/mine sector for hoppers and conveyor belts, was made available as reference.

[0081] Table 1 with ludication of the raw materials and composition

TABLE-US-00001 Proportion Raw material [% by weight] 1,4-Butanediol adipate (OH number 50 mg KOH/g) 65.70 1,4-Butanediol 6.93 4,4-Diphenylmethane diisocyanate 26.64 Tyzor AA105.sup.1) 0.001 Loxiol 3324.sup.2) 0.40 Stabaxol I.sup.3) 0.26 Irganox 1010.sup.4) 0.07 .sup.1)Titanium catalyst from Dorf Ketal Chemicals India Pvt. Ltd., Mumbai .sup.2)Wax from Emery Oleochemicals GmbH, Dsseldorf .sup.3)Hydrolysis stabilizer from Rhein Chemie GmbH, Mannheim .sup.4)Oxidation stabilizer from BASF SE, Ludwigshafen

2. Production of the CPU Layer

[0082] The formulation shown in Table 2 was reacted in an open mould to produce the cast polyurethane. Tests specimens for determining the mechanical properties were subsequently made from this CPU. The properties of the CPU or of the test bars are shown in Table 3.

[0083] Table 2 with indication of the raw materials and composition

TABLE-US-00002 Proportion Raw material [parts by weight] Desmodur MDQ 24163.sup.1) 100 Baytec D24.sup.2) 200 1,4-Butanediol.sup.3) 8.6 Catalyst SD 2.4.sup.4) 0.35 .sup.1)MDI prepolymer from Covestro Elastomers SAS having an NCO content of 16.4% by weight .sup.2)Polyadipate polyol from Covestro Elastomers SAS having a hydroxyl number of 56 mg KOH/g .sup.3)Chain extender from BASF .sup.4)Catalyst from Covestro Elastomers SAS

[0084] Table 3 with mechanical properties of TPU-CPU-rubber

TABLE-US-00003 Rubber, RABERMIX Trelleborg highly TPU as per CPU as per Santiago de Chile abrasion-resistant Property Unit Table 1 Table 2 SIOM 73 rubber plate RF 20 Hardness.sup.1 Shore A 87 65 78 65 100% modulus.sup.2 MPa 6.3 2.9 3.2 n.a. 300% modulus.sup.3 MPa 14.6 5.8 11.3 n.a. Tensile strength.sup.4 MPa 57 43 14 24.5 Tear propagation kN/m 70 24 68 n.a. resistance.sup.5 Elongation at break.sup.6 % 594 530 365 400 Rebound resilience.sup.7 % 51 59 28 n.a. Abrasion loss.sup.8 mm.sup.3 16 40 61 100 .sup.1Hardness in accordance with DIN 53505 .sup.2100% modulus in accordance with DIN 53504 .sup.3300% modulus in accordance with DIN 53504 .sup.4Tensile strength in accordance with DIN 53504 .sup.5Tear propagation resistance in accordance with ISO 34-1 .sup.6Elongation at break in accordance with DIN 53504 .sup.7Rebound resilience in accordance with DIN 53512 .sup.8Abrasion loss in accordance with ISO 4649

[0085] Table 3 shows the advantageous properties of the TPU covering layer and the CPU support layer compared to known rubber systems. The TPU layer of the elastomer sandwich systems of the invention has a significantly improved rebound resilience and significantly lower abrasion compared to the rubber from Siom which has a similar tear propagation resistance and has been used as benchmark. Compared to an abrasion-stable rubber from Trelleborg, the tensile strength and elongation at break is improved and, in particular, the abrasion resistance is also improved.

[0086] Compared to the rubber from Siom and the abrasion-stable rubber from Trelleborg, the CPU displays an improved tensile strength, elongation at break and abrasion resistance combined with very good rebound resilience.

[0087] The abrasion loss in accordance with ISO 4649 (applicable to CPU and TPU) was calculated as follows:

Abrasion in mm.sup.3=(XY)/Z*K,

[0088] where

[0089] X is the mass of the test specimen before the measurement,

[0090] Y is the mass of the test specimen after the measurement,

[0091] Z is the density of the component and

[0092] K is the correction factor.

3. Production of the Elastomer Sandwich Systems

[0093] The elastomer sandwich elements were produced by placing the cleaned TPU layer in a mould and subsequently pouring the required raw materials (I, II and III) by hand or with machine mixing into the mould. The noncellular cast polyurethane CPU was formed in direct contact with the TPU. The mould temperature was 80 C.

[0094] A system analogous to Table 3 was used as reaction mixture for producing the noncellular cast polyurethane.

[0095] The elastomer sandwich systems produced had densities of 1200 g/cm.sup.3.

[0096] The corresponding metal composite elements were produced by applying the elastomer sandwich system to a metal support using an adhesive system.