Reinforced reusable flexible hose

Abstract

The reinforced flexible hose for transporting fluids comprises at least one first load-bearing layer (10) made of a first polymeric material, at least one second covering layer (20) made of a second polymeric material and arranged on the outside of the at least one first load-bearing layer (10), and at least one reinforcing layer (30) made of a third polymeric material and interposed between the at least one first and second layers (10, 20). The first and second polymeric materials are thermoplastic elastomers, and the third polymeric material is a thermoplastic polymeric material. As a result of the compatibility of the first, second and third polymeric materials with each other, the flexible hose can be ground without separation between the at least one first and second layers (10, 20) and the at least one reinforcing layer (30) to obtain a ground mixture (60) consisting of the first, second and third polymeric materials.

Description

[Technical field]

[0001] The present invention relates to the technical field of flexible hoses, for example irrigation hoses, in particular to a reusable reinforced flexible hose, as well as to a grinding mixture obtained by grinding such a flexible hose and to a method for producing a reinforced flexible hose starting from such a grinding mixture. definition

[0002] In this specification, the expressions "fiber reinforced layer" or "reinforced layer" or derivatives thereof are used to denote a layer of at least one fiber thread disposed on an underlying layer. The "reinforced layer" is disposed on the load-bearing layer so as to leave a generally square, rectangular, or diamond-shaped portion therebetween.

[0003] In this document, the expressions "cross-hatched fiber layer" or "cross-hatch layer" or "cross-hatching", or derivatives thereof, are used to denote a layer consisting of at least two threads or groups of threads that are inclined in opposite directions, overlapping but not connected to each other, and wound helically around the load-bearing layer. Cross-hatching therefore consists of two or more overlapping spirals.

[0004] As used herein, the expression "compatible materials" or its derivatives is used to indicate materials that have mutual chemical and / or physical compatibility, i.e., materials that, when joined, produce a bond suitable for withstanding the transmission of tensile or shear forces through the interface. Hence, the greatest compatibility is observed in materials that are identical or have the same predominant matrix.

[0005] In this specification, the expression "matrix" of a polymeric material or its derivatives is used to indicate a polymer capable of providing the molecular structure of the final product.

[0006] In this document, the expression "polymeric material" or its derivatives are used to denote both single polymers and mixtures (eg, blends or compositions) of multiple polymers. [Background technology]

[0007] It is known that reinforced flexible hoses consist essentially of two parts: a tubular part made of polymer material and a part made of threads forming the reinforcement. Generally, the tubular part consists of two or more layers made of polymer material, between which the reinforcing threads are placed.

[0008] Typically, the reinforcing threads are made of materials that are not compatible (mixed) with the polymeric materials that form the part made of the polymer, and the materials that form the layers of the polymeric part are not necessarily compatible with each other, which is a necessary condition for the reusability of the flexible hose.

[0009] However, even if the polymer component is of a compatible material, the incompatibility between the polymer component and the thread material requires labor to separate the two components for the purpose of reusing the hose.

[0010] This operation is long, expensive and difficult to carry out, making the reuse of flexible hoses economically infeasible, even at an industrial level as a recycling of production waste.

[0011] Moreover, 100% separation of the threads from the tubular parts of the hose is basically impossible, which leads to the fact that the granules of recycled material always contain a more or less high proportion of impurities. Obviously, this has a negative effect on the mechanical properties of the hoses made of this material. Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to overcome the drawbacks outlined above by providing a reinforced flexible hose that is highly effective and relatively cost-effective.

[0013] It is a further object of the present invention to provide a reinforced flexible hose that is easily reusable.

[0014] It is a further object of the present invention to provide a reinforced flexible hose which, when properly recycled, results in a novel flexible tube having mechanical properties comparable to the original.

[0015] These and other objects, which will become more apparent below, are achieved by a reinforced flexible hose, as well as a grinding mixture and a method for producing the same, as described and / or claimed and / or exemplified herein. [Means for solving the problem]

[0016] Accordingly, the present invention provides a reinforced flexible hose for transporting fluids, comprising: at least one first load-bearing layer made of a first polymeric material; at least one second coating layer made of a second polymeric material and disposed externally of the at least one first load-bearing layer; at least one reinforcing layer made of a third polymeric material and interposed between the at least one first and second layer; the first and second polymeric materials are thermoplastic elastomers and the third polymeric material is of the thermoplastic type; The flexible hose is one in which the first, second and third polymeric materials are compatible with one another.

[0017] In this manner, the flexible hose can be ground without separating the load-bearing and covering layers from the reinforcing layer to obtain a ground mixture of the first, second and third polymeric materials.

[0018] Suitably, the ground mixture may have a Shore A hardness, measured in accordance with ISO 868:2003, that is greater than the weighted average of the Shore A hardnesses, measured in accordance with ISO 868:2003, of the first and second polymeric materials (preferably between 8ShA and 20ShA, more preferably between 10ShA and 18ShA).

[0019] Advantageously, the first and / or second polymeric material may be a compound whose composition includes a third polymeric material.

[0020] For example, the thermoplastic elastomers forming the first and second polymeric materials may be a TPV comprising EDPM and polypropylene (e.g., SANTOPRENE®, marketed by EXXONMOBIL® Corporation), or a TPE-S comprising SEBS and polypropylene (e.g., Nilflex SH, marketed by Taro Plast SpA), while the third thermoplastic polymeric material may be polypropylene.

[0021] On the other hand, a crushed mixture may be provided, obtained by crushing the flexible hose described above, said mixture having a plurality of polygonal pieces with a larger diagonal, preferably lying between 3 mm and 25 mm.

[0022] On the other hand, a method for producing a reinforced flexible hose for transporting fluids starting from a grinding mixture according to claim 9, comprising the steps: extruding a fourth polymeric material comprising or consisting of the ground mixture to obtain at least one first layer, preferably a load-bearing layer; and forming at least one reinforcing layer on the load-bearing layer, preferably made from a fifth polymeric material that is compatible with the fourth polymeric material.

[0023] Suitably, the fourth polymeric material may comprise the ground mixture and at least one sixth polymeric material compatible with the ground mixture in a weight ratio of between 1:99 and 10:90.

[0024] Advantageously, the ground mixture may be obtained starting from production waste of the production line of the hose from which it originates. The dependent claims define advantageous embodiments of the invention.

[0025] Further features and advantages of the present invention will become more apparent in the light of the detailed description of some preferred but non-exclusive embodiments of the invention, given by way of non-limiting examples with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram of a production line for reinforced flexible hoses 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] With reference to the above mentioned figures, the present specification describes a flexible garden hose 1 for watering flowers, plants etc. Such a hose is suitable to be connected by means of special couplings in a manner known per se to a domestic water main, so that the hose transports drinking water from an appliance in the domestic water main, e.g. a tap, to the point to be watered, e.g. a garden, a flower bed etc.

[0028] In the following, reference will always be made to a garden hose, but it is clear that the hose according to the invention can be used for any purpose without departing from the scope of protection of the appended claims.

[0029] The hose 1 may essentially comprise one or more inner load-bearing layers 10, one or more outer jacket layers 20, and one or more fiber reinforced layers 30 interposed therebetween.

[0030] Although reference will be made below to a three-layer hose, it is clear that the hose according to the invention, whether made from polymer material or from reinforcing fibers, can have any number of layers without departing from the protective scope of the appended claims.

[0031] The inner layer 10 and the outer layer 20 may be made of respective compatible polymeric materials, and are preferably made of the same polymeric material.

[0032] These polymeric materials may be of the thermoplastic elastomer type, for example TPV, TPE-S, TPE-O or TPE-A.

[0033] Preferably, the material of the inner layer 10 and the outer layer 20 may be a TPV compound having an EPDM matrix, e.g., EPDM, a mixture of polypropylene and paraffin oil, or a SEBS-based TPE-S compound, e.g., SEBS, a mixture of polypropylene and paraffin oil.

[0034] Suitably, the overall Shore A hardness, measured according to ISO 868:2003, of the materials of the inner layer 10 and the outer layer 20 may be between 60ShA and 75ShA for the above-mentioned EPDM based compounds, and between 35ShA and 55ShA for the above-mentioned SEBS based compounds.

[0035] If there is a difference in Shore A hardness of the materials of the inner layer 10 and the outer layer 20, the overall hardness may be measured from the average hardness of the two materials forming such layers, weighted accordingly to the weight of the individual layers relative to the total weight of the layers.

[0036] Furthermore, advantageously, the overall melt flow index, measured according to ISO 1133-230°C-5Kg, of the material of the inner layer 10 or the outer layer 20 may be between 1 g / 10 min and 5 g / 10 min for the abovementioned EPDM based compounds, and the overall melt flow index, measured according to ISO 1133-190°C-5Kg, of the material of the inner layer 10 and the outer layer 20 may be between 5 g / 10 min and 10 g / 10 min for the abovementioned SEBS based compounds.

[0037] On the other hand, the reinforcing layer 30 may be made of a fibrous polymeric material compatible with the materials mentioned above. For example, with the inner layer 10 and outer layer 20 made of TPV, TPE-S or TPE-O, the reinforcing layer 30 may be made of polypropylene, and with the inner layer 10 and outer layer 20 made of TPE-A, the reinforcing layer 30 may be made of polyamide. Suitably, the reinforcing layer 30 may have any configuration, for example braided or cross-hatched.

[0038] The hose 1 may be produced in a manner known per se, in particular as shown in FIG. 1, by extruding a first polymer material in a first extruder 40 to obtain an inner layer 10, followed by a reinforcing layer on the inner layer 10 in a knitting, cross-hatching or spiral-forming machine 41, and then co-extruding a covering layer 20 onto the output semi-finished product by means of an extruder 42.

[0039] Due to the compatibility between the aforementioned polymer materials, the flexible hose 1 may be crushed in a crusher 50 of a type known per se, for example a TRM600 marketed by CMG Spa, without prior separation of the polymer parts of the hose consisting of the inner layer 10 and the outer layer 20 and the reinforcing layer 30.

[0040] This makes it possible to obtain a ground mixture 60 consisting of the materials of the layers 10, 20 and 30 which fit together. Suitably, the pieces may be generally polygonal, for example square or rectangular, with a larger diagonal dm lying between 3 mm and 25 mm.

[0041] The Shore A hardness of the ground mixture 60, measured according to ISO868:2003, may be greater than the overall Shore A hardness of the materials of the inner layer 10 and outer layer 20, which is between 8ShA and 20ShA, preferably between 10ShA and 18ShA.

[0042] In a preferred, but non-exclusive embodiment of the invention, in the above example of inner layer 10 and outer layer 20 made from an EPDM-based TPV containing polypropylene, and reinforcing layer 30 made from polypropylene, ground mixture 60 includes EPDM and polypropylene, the polypropylene being in a greater amount than the amount of polypropylene in the untreated TPV.

[0043] In this case, the weighted average of the Shore A hardness measured in accordance with ISO 868:2003 of the materials forming the inner layer 10 and the outer layer 20 may be between 60ShA and 75ShA, and the Shore A hardness of the ground mixture 60 measured in accordance with ISO 868:2003 may be between 70ShA and 90ShA.

[0044] Furthermore, in this case, the melt flow index of the ground mixture 60, measured according to ISO 1133-230°C-5kg, may be higher than the melt flow index of the materials of the inner layer 10 and the outer layer 20, which is between 8g / 10min and 25g / 10min.

[0045] For example, the melt flow index, measured in accordance with ISO 1133-230°C-5Kg, of each of the materials of the inner layer 10 and the outer layer 20 may be between 1 g / 10 min and 5 g / 10 min, and the melt flow index, measured in accordance with ISO 1133-230°C-5Kg, of the ground mixture 60 may be between 10 g / 10 min and 30 g / 10 min.

[0046] In a further preferred, but non-exclusive, embodiment of the present invention, where the inner layer 10 and the outer layer 20 are made of a SEBS-based TPE-S that includes polypropylene and the reinforcing layer 30 is made of polypropylene, the ground mixture 60 includes SEBS and polypropylene, the polypropylene being in a greater amount than the amount of polypropylene in the untreated TPE-S.

[0047] In this case, the weighted average of the Shore A hardness measured in accordance with ISO 868:2003 of the materials forming the inner layer 10 and the outer layer 20 may be between 35ShA and 55ShA, and the Shore A hardness of the ground mixture 60 measured in accordance with ISO 868:2003 may be between 55ShA and 75ShA.

[0048] The ground mixture 60 may be used as a raw material for manufacturing novel reinforced flexible hoses for transporting fluids, as shown diagrammatically in Figure 1. Optionally, for this purpose, the ground mixture 60 may be suitably enriched, for example by adding paraffin oil.

[0049] In this sense, the invention may define a method for recycling the production waste of flexible hose manufacturing lines, in which discarded flexible hoses are reused and converted into raw material for new hoses.

[0050] In this manufacturing line, the ground mixture 60 is either used as is or is blended with a compatible green material 61 and cut, as shown in FIG.

[0051] The weight ratio between the ground mixture 60 and the compatible raw material 61 may be between 1:99 and 30:70. If this weight ratio is exceeded, the mechanical properties of the resulting polymer will not be suitable for producing flexible hoses of the type described above.

[0052] Considering the fact that the industrially acceptable average production waste for flexible hose production lines is a maximum of 5%, to obtain a weight ratio in a large amount of grinding mixture 60, a large amount of production waste would need to be accumulated over several working days.

[0053] This obviously requires proper management of production waste and storage space at production sites.

[0054] Therefore, preferably, the weight ratio between the ground mixture 60 and the compatible raw material 61 may be between 1:99 and 10:90.

[0055] This makes it possible to recycle up to one working day's production waste on a regular basis, for example every half working day or at the end of the working day, without the need for an accumulation of production waste and the associated management.

[0056] The combination of the raw material 61 and the ground mixture 60 may form a first polymer material and / or a second polymer material as shown in Figure 1 without departing from the scope of protection of the appended claims. In other words, the combination of the raw material 61 and the ground mixture 60 may be used to obtain a load-bearing layer or a covering layer of a hose.

[0057] In the above example where raw material 61 is untreated TPV, ground mixture 60 may originate from the grinding of TPV hose production waste as described above.

[0058] In order to repeat the above-mentioned cycle in a circular economy logic, the novel hose may comprise a reinforcing layer made of a compatible material, for example polypropylene.

[0059] The aforementioned features make it possible to obtain a complete and easily reusable hose by simply inserting the hose into the crusher 60, without the prior operation of separating the reinforcing layer from the remainder of the hose.

[0060] The resulting ground mixture may be used to make new hoses, obviously reducing both the costs and the environmental impact associated with hose manufacturing. The invention will be more clearly understood in the light of the following examples.

[0061] <Example> Preparing the hose Four samples measuring 10 m of hose were prepared using the following raw materials: Inner layer: SANTOPRENE® 201-64, available from EXXONMOBIL® Corporation Outer layer: SANTOPRENE® 201-73, marketed by EXXONMOBIL® Corporation Reinforcement layer. PP yarn 1200DN "AT" TANG C. WHITE marketed by Industrias Ponsa, SA.

[0062] The hoses were produced in a manner known per se by extruding the inner and outer layers by means of an extruder of a type known per se and forming on the inner layer a knitted layer having a tricot-type chain stitch of NTS® (samples 3 and 4) or DCT (samples 1 and 2) type by means of a knitting machine of a type known per se. The weight distribution percentages for the four samples are as follows: (Table 1) TIFF2024500517000002.tif42144

[0063] Shore hardness measurement The overall Shore A hardness of the materials forming Samples 1-4 above was measured by an ATS FAAR Shore A type Shore hardness tester according to the ISO868:2003 standard. The overall hardness was measured by calculating the weighted average of the Shore A hardness of an inner layer made of SANTOPRENE® 201-64 (hardness ShA: 64) and an outer layer made of SANTOPRENE® 201-73 (hardness ShA: 73), both measured expressly according to the above-mentioned criteria. The results are reported in the table below. (Table 2) TIFF2024500517000003.tif39144

[0064] Measurement of MFI The MFI of the materials forming the tubular layers of the above-mentioned Samples 1 to 4 (SANTOPRENE® 201-64 and SANTOPRENE® 201-73) was measured using an INSTRON® CEAST Melt Flow Tester MF 30 type melt flow tester in accordance with the ISO 1133-230°C-5Kg standard. The results are reported in the table below. (Table 3) TIFF2024500517000004.tif33144

[0065] Hose shattering Each of the four hose samples mentioned above was inserted as is into a crusher of the type TRM600 marketed by CMG Spa and crushed without prior separation of the reinforcing layer from that made of polymeric material. The fragments of the mixture thus obtained were screened using a sieve with a mesh of 15 mm.

[0066] Determination of Shore Hardness of Mixtures For each of the mixtures resulting from the grinding of the above samples, the Shore A hardness was measured according to the ISO 868:2003 standard using the same Shore hardness tester as above. The results are reported in the table below. (Table 4) TIFF2024500517000005.tif42144

[0067] Therefore, it is evident that the polypropylene yarns of the various hose samples when mixed with polymeric materials significantly increased the Shore A hardness of the mixture.

[0068] Determining the MFI of a mixture For each of the mixtures resulting from grinding the above mentioned samples, the MFI was measured according to the ISO 1133-230°C-5Kg standard using the same melt flow tester as above. The results are reported in the table below. (Table 5) TIFF2024500517000006.tif42144

[0069] Therefore, it is evident that the polypropylene yarns of the various hose samples when blended with polymeric materials significantly increased the MFI of the blends. Preparing for a new hose

[0070] The mixtures obtained from the four aforementioned samples were mixed with untreated SANTOPRENE® 201-64 granules in a ratio of 5 to 95. Such mixtures of untreated and ground material were extruded to obtain the load-bearing layers of each of the new samples of 10 m hose. Each of these load-bearing layers was inserted into a braiding machine to obtain the polypropylene reinforcing layer described above, and subsequently SANTOPRENE® 201-73 was extruded onto the semi-finished product emerging from the braiding machine to obtain the covering layer. The weight distribution of the new hose samples is the same as that of samples 1 to 4 described above. Essentially, four hose samples were obtained that were similar to the starting sample both from a qualitative and mechanical standpoint.

[0071] Mechanical properties to weight ratio To determine how the mechanical properties of the polymeric material change as the weight ratio between the ground mixture and the unprocessed material is changed, various samples of SANTOPRENE® 201-73 and the above-mentioned "Sample Mix 1" (SAMP MIX 1) were prepared in ratios ranging from 97:3 to 50:50, as reported in the table below.

[0072] The Shore A hardness according to the ISO868:2003 standard was measured for each sample using an ATS FAAR Shore A type Shore hardness tester, the MFI according to the ISO1133-230°C-5Kg standard using an INSTRON® CEAST Melt Flow Tester MF30 type melt flow tester, and the tensile force according to the ISO37 / ISO527-2-2012 standard using a Galdabini brand dynamometer, Sun2500 model with a 25kN load cell and a strain gauge with a maximum speed of 600mm / min.

[0073] The tests show that as the proportion of Sample Mix 1 (SAMP MIX 1) increases, there is a substantial decrease in the mechanical properties of interest, showing the maximum difference at 35% of the milled mixture.

[0074] The maximum weight ratio between the raw polymer and the ground mixture that makes it possible to obtain an extruded polymer suitable for making reinforced flexible hoses is therefore 70:30. (Table 6) TIFF2024500517000007.tif111170

Claims

1. A method for manufacturing a reused flexible hose for transporting a fluid, the method comprising: Providing a grinding mixture (60) obtained by grinding a reinforced flexible hose, said flexible hose comprising: At least one first load-bearing layer (10) made of a first polymeric material; at least one second covering layer (20) made of a second polymeric material and arranged on the exterior of the at least one first load-bearing layer (10); at least one reinforcing layer (30) made of a third polymeric material and interposed between said at least one first and second layer (10, 20); the first and second polymeric materials are thermoplastic elastomers and the third polymeric material is a thermoplastic polymeric material; said first, second and third polymeric materials being compatible with one another such that they can be milled without separation between said at least one first and second layer (10, 20) and said at least one reinforcing layer (30); and extruding a fourth polymeric material comprising said ground mixture (60) to obtain at least one first layer of said recycled flexible hose, said fourth polymeric material comprising said ground mixture (60) and at least one fifth polymeric material (61) compatible therewith, said fifth polymeric material being an untreated thermoplastic elastomer; The method of claim 1, wherein said fourth polymeric material has a weight ratio between said ground mixture (60) and said at least one fifth polymeric material (61) of between 1:99 and 30:

70.

2. 2. The method of claim 1, wherein the ground mixture (60) has a Shore A hardness, measured in accordance with ISO 868:2003, that is greater than a weighted average of the Shore A hardnesses, measured in accordance with ISO 868:2003, of the at least one first and second polymeric materials.

3. 3. The method according to claim 2, wherein the Shore A hardness of the ground mixture (60), measured according to ISO 868:2003, is greater than the weighted average of the Shore A hardnesses, measured according to ISO 868:2003, of the at least one first and second polymeric material, of 8ShA to 20ShA, preferably 10ShA to 18ShA.

4. 4. The method according to claim 1, 2 or 3, wherein the first and second polymeric materials are EPDM based, the weighted average of the Shore A hardness measured according to ISO 868:2003 of the at least one first and second polymeric material is between 60ShA and 75ShA, and the Shore A hardness measured according to ISO 868:2003 of the ground mixture (60) is between 70ShA and 90ShA.

5. 4. The method according to claim 1, 2 or 3, wherein the first and second polymeric materials are SEBS based, the weighted average of the Shore A hardness measured according to ISO 868:2003 of the at least one first and second polymeric material is between 35ShA and 55ShA, and the Shore A hardness measured according to ISO 868:2003 of the ground mixture (60) is between 55ShA and 75ShA.

6. 5. The method according to any one of claims 1 to 4, wherein the first and second polymeric materials are EPDM based, and the melt flow index, measured according to ISO 1133-230°C-5Kg, of the at least one first or second polymeric material is between 1 g / 10 min and 5 g / 10 min, and the melt flow index, measured according to ISO 1133-230°C-5Kg, of the ground mixture (60) is between 10 g / 10 min and 30 g / 10 min.

7. The method of claim 1 , wherein the first polymeric material and / or the second polymeric material is a compound that comprises the third polymeric material.

8. 8. The method according to any one of claims 1 to 7, wherein the thermoplastic elastomer is a TPV based on EDPM containing polypropylene or a TPE-S based on SEBS containing polypropylene, and the third polymeric material is polypropylene.

9. A method according to any one of claims 1 to 8, wherein the ground mixture has a plurality of polygonal pieces having a larger diagonal (dm) between 3 mm and 25 mm.

10. A recycled, reinforced flexible hose obtainable by the method according to any one of claims 1 to 9.

Images