SINGLE-LAYER OR MULTILAYER TUBULAR STRUCTURE BASED ON RECYCLED POLYAMIDE

Abstract

A composition including: (a) 30% to 99.8% by weight by weight of recycled material from a used single-layer and/or multilayer tube and/or tank having initially transported or contained motor vehicle fluids, the tube and/or the tank having a composition which predominantly includes at least one polyamide, the used tube and/or the used tank having been ground into granules and the fluid residues present in the tube and/or tank having been totally or partially extracted, (b) up to 70% of a semicrystalline aliphatic polyamide, (c) up to 0.2% of an additive, the polyamide of the used tube and/or the used tank having functions resulting from oxidation reactions chosen from the primary amide functions, nitriles, terminal methyl groups, alkenes, formamides, imides, carboxylic acids and alcohols and mixtures thereof, in a mole ratio greater than that of the same polyamide constituting a non-used tube and/or tank which has not yet transported or contained motor vehicle fluids.

Claims

1. A composition comprising: (a) 30% to 99.8% by weight of recycled material from a used single-layer and/or multilayer tube and/or tank having initially transported or contained motor vehicle fluids, said tube and/or said tank consisting of a composition which predominantly comprises at least one polyamide, said used single-layer and/or multilayer tube and/or said used tank having been ground into granules and the fluid residues present in said tube and/or tank having been totally or partially extracted, before or after grinding of said tube and/or tank, (b) up to 70% of a semicrystalline aliphatic polyamide, (c) up to 45% by weight of at least one impact modifier, (d) up to 20% by weight of at least one plasticizer, (e) up to 0.2% of an additive, said polyamide of said used tube and/or said used tank having functions resulting from oxidation reactions chosen from the primary amide functions, nitriles, terminal methyl groups, alkenes, formamides, imides, carboxylic acids and alcohols and mixtures thereof, in a mole ratio relative to the amide functions greater than that of the same polyamide constituting a non-used tube and/or tank which has not yet transported or contained motor vehicle fluids.

2. The composition as claimed in claim 1, wherein said mole ratio of functions produced by oxidation reactions ranges from 1/10 000 to 1/20.

3. The composition as claimed in claim 1, wherein said mole ratio of imide functions ranges from 1/1000 to 1/20.

4. The composition as claimed in claim 1, wherein said mole ratio of carboxylic acid functions ranges from 1/5000 to 1/20.

5. The composition as claimed in claim 1, wherein said mole ratio of alcohol functions ranges from 1/1000 to 1/20.

6. The composition as claimed in claim 1, wherein said mole ratio of primary amide functions ranges from 1/2000 to 1/20.

7. The composition as claimed in claim 1, wherein said mole ratio of nitrile functions ranges from 1/1000 to 1/20.

8. The composition as claimed in claim 1, wherein said mole ratio of terminal methyl functions ranges from 1/5000 to 1/50.

9. A single-layer or multilayer tubular structure (MLT) intended for transporting motor vehicle fluids comprising at least one layer (1) consisting of a composition as defined in claim 1.

10. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein it has during the first storage of gasoline a maximum of 0.3 g/m.sup.2 of insoluble extract.

11. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the extraction of said fluid residues is performed by means of washing or ventilation.

12. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the structure is multilayered and comprises at least one layer (2).

13. The multilayer tubular structure (MLT) as claimed in claim 12, wherein said layer (2) consists of a composition predominantly comprising at least one semicrystalline aliphatic polyamide and optionally at least one impact modifier, and when the layer (2) consists of a composition predominantly comprising at least one semicrystalline aliphatic polyamide which is PA12 and/or PA610 and/or PA612 and/or PA1010, then said composition comprises said impact modifier, and said layer (2) consists of at least 90% non-recycled material.

14. The multilayer tubular structure (MLT) as claimed in claim 12, wherein it comprises at least one layer (2) consisting of a composition predominantly comprising at least one semicrystalline aliphatic polyamide, semiaromatic polyamide or polyolefin, said layer (2) consisting of at least 90% non-recycled material.

15. The multilayer tubular structure (MLT) as claimed in claim 14, wherein said layer (2) consists of a composition predominantly comprising at least one semiaromatic polyamide.

16. The multilayer tubular structure (MLT) as claimed in claim 14, wherein said layer (2) consists of a composition predominantly comprising at least one polyolefin.

17. The multilayer tubular structure (MLT) as claimed in claim 14, wherein said layer (1) is between a layer (2) and a layer (2).

18. The multilayer tubular structure (MLT) as claimed in claim 14, wherein the layer (2) is the layer that is in contact with the fluid.

19. The multilayer tubular structure (MLT) as claimed in claim 14, wherein the layer (2) is as defined for the layer (2).

20. The multilayer tubular structure (MLT) as claimed in one of claim 14, wherein at least one binder layer (3) is present, said layer (3) being located between layer (2) and layer (1) and/or between layer (1) and layer (2).

21. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein said layer (1) represents at least 10% of the total thickness of said single-layer or multilayer tubular structure (MLT).

22. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein said layer (1) consists of a composition comprising: at least 50% by weight of at least one semicrystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted C.sub.C of from 6 to 18; from 0 to 25% by weight of at least one semicrystalline aliphatic polyamide noted B and having an average number of carbon atoms per nitrogen atom noted C.sub.B=C.sub.C?1; from 0 to 25% by weight of a semicrystalline aliphatic polyamide noted A and having an average number of carbon atoms per nitrogen atom noted C.sub.A=C.sub.B?1; 0% to 45% by weight of at least one impact modifier, from 0% to 20% by weight of at least one plasticizer, from 0% to 0.2% by weight of at least one additive, the sum of the constituents being equal to 100%.

23. The single-layer or multilayer tubular structure (MLT) as claimed in claim 22, wherein said composition of the layer (1) is free of plasticizer and/or impact modifier.

24. The single-layer or multilayer tubular structure (MLT) as claimed in claim 22, wherein said composition of the layer (1) comprises at least one compound chosen from a plasticizer, an impact modifier and an additive.

25. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the fluid transported by said single-layer and/or multilayer tube or stored in said tank is the same as that of said single-layer or multilayer tubular structure (MLT).

26. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the fluid transported by said single-layer and/or multilayer tube or stored in said tank is different from that of said multilayer tubular structure (MLT).

27. The multilayer tubular structure (MLT) as claimed in claim 9, wherein the layer (2) consists of a composition comprising: at least 50% by weight, of at least one semicrystalline aliphatic polyamide noted D and having an average number of carbon atoms per nitrogen atom noted CD of from 6 to 18; from 0 to 25% by weight of at least one semicrystalline aliphatic polyamide noted E and having an average number of carbon atoms per nitrogen atom noted C.sub.E=C.sub.D?1; from 0 to 25% by weight of a semicrystalline aliphatic polyamide noted F and having an average number of carbon atoms per nitrogen atom noted C.sub.F=C.sub.E?1; from 3% to 45% by weight of at least one impact modifier; from 0% to 20% by weight of at least one plasticizer; from 0% to 0.2% by weight of at least one additive; from 0% to 35% by weight of at least one antistatic filler; the sum of the constituents being equal to 100%.

28. The multilayer tubular structure (MLT) as claimed in claim 27, wherein said composition of said layer (1) is free of polyamides noted A and B and said composition of said layer (2) comprises polyamides chosen from those noted E, F and a mixture thereof.

29. The multilayer tubular structure (MLT) as claimed in claim 27, wherein said composition of said layer (1) comprises polyamides chosen from those noted A, B and a mixture thereof, and said composition of said layer (2) is free of polyamides noted E and F.

30. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the layer (1) is from a recycled single-layer tube.

31. The single-layer or multilayer tubular structure (MLT) as claimed in claim 9, wherein the layer (1) is from a recycled multilayer tube.

32. The multilayer tubular structure (MLT) as claimed in claim 12, wherein the MLT consists of three layers having the following structure: (2)//(1)//(2).

33. A process for preparing a tubular structure as defined in claim 9, wherein it involves extruding the composition to constitute the layer (1), after collecting used pipes from a motor vehicle, in an extruder optionally equipped with a degassing zone.

34. The process as claimed in claim 33, wherein the used pipes are ground into granules after collection.

35. The process as claimed in claim 33, wherein the fluid residues have been extracted from the used pipes before or after grinding.

36. The process as claimed in claim 35, wherein the extraction is performed by means of washing or ventilation.

37. The process as claimed in claim 36, wherein the washing is performed using a solvent.

38. The process as claimed in claim 37, wherein the ventilation is performed using an inertized oven.

39. The process as claimed in claim 35, wherein the extraction is performed after grinding by means of a degassing zone in said extruder.

40. The process as claimed claim 35, wherein the used pipes before or after grinding are cleaned to remove any oligomers present in the used pipes.

41. A method of using a used single-layer and/or multilayer tube and/or tank which has initially transported or contained motor vehicle fluids, as defined in claim 1, for the preparation of a single-layer tubular structure intended for transporting motor vehicle fluids, said used single-layer and/or multilayer tube and/or said used tank having been ground into granules and the fluid residues present in said tube and/or tank having been totally or partially extracted, before or after grinding of said tube and/or tank and said tubular structure having during the first storage of gasoline, less than 0.3 g/m.sup.2 of insoluble extract.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0428] FIG. 1 shows the Fourier Transform Infrared (FTIR) analysis in Attenuated Total Reflectance (ATR) mode of a ground VHU PA 11 PL gasoline line (continuous gray line), and compared to a PA 11 PL gasoline line 100% based on virgin material (continuous black line).

[0429] FIG. 2 shows the CH2CO areas of the various secondary amide, primary amide and carboxylic acid functions in 13C NMR in a solvent mixture with an HFIP/CD2CI2 ratio of ?.

[0430] Top spectrum; PA 11 PL ground ELV gasoline line and bottom spectrum: PA 11 PL gasoline line 100% based on virgin material.

EXAMPLES

Compositions of the Invention

Single-Layer Tubes of the Invention:

[0431] The tubes are 8?1 mm in size.

[0432] Preparation of the single-layer structures (tubes):

[0433] The single-layer structures are produced by extrusion. A Maillefer industrial extrusion line is used.

[0434] This line comprises a single-screw extruder equipped with a screw profile suitable for polyamides. In addition, the extrusion line includes: [0435] a die-punch assembly, located at the end of the extrusion head; the inside diameter of the die and the outside diameter of the punch are chosen as a function of the structure to be made and of the materials of which it is composed, and also as a function of dimensions of the tube and of the line speed; [0436] a vacuum tank with an adjustable level of vacuum. In this tank circulates water maintained in general at 20? C., into the fa?ade of which is inserted a gauge for conforming the tube to its final dimensions. The diameter of the gauge is adapted to the dimensions of the tube to be made, typically from 8.1 to 10 mm for a tube with an outside diameter of 8 mm and a thickness of 1 mm; [0437] a cooling tank in which water is maintained at about 20? C., for cooling the tube along the path from the head to the drawing bench; [0438] a diameter measurer; [0439] a drawing bench.

[0440] Before the tests, in order to ensure the best properties for the tube and a good extrusion quality, it is verified that the extruded materials have a residual moisture content before extrusion of less than 0.08%. If this is not the case, an additional step of drying the material before the tests is performed, generally in a vacuum dryer, overnight at 80? C.

[0441] The tubes, which meet the characteristics described in the present patent application, were taken, after stabilization of the extrusion parameters, the target dimensions of the tubes no longer changing over time. The diameter is monitored by a laser diameter measurer installed at the end of the line.

[0442] The line speed is typically 20 m/min. It generally varies between 5 and 100 m/min.

[0443] The speed of the extruder screws depends on the thickness and diameter of the tube, as is known to those skilled in the art.

[0444] In general, the temperature of the extruders and tools (head and joint) should be set so as to be sufficiently higher than the melting point of the compositions under consideration, such that they remain in the molten state, thus preventing them from solidifying and blocking the machine.

[0445] The single-layer tubes produced by extrusion above were then evaluated on several criteria: [0446] Aging: This is the durability; in other words, it denotes the resistance of the tube to oxidative aging in hot air. The tube is aged in air at 150? C., and then shocked according to the standard DIN 73378, which is produced at ?40? C. The half-life (in hours) is indicated, corresponding to the time after which 50% of the tubes tested break. A qualitative commentary accompanies this value. [0447] A ++ rating is given for durability that may be described as very good, corresponding to ?200h half-life. [0448] A + rating is given for durability (resistance to thermo-oxidative aging) that may be described as good, corresponding to >100h half-life (and <200h). [0449] A +- rating is given for durability (resistance to thermo-oxidative aging) that may be described as acceptable, corresponding to ?50h half-life (and <100h). [0450] A ? rating is given for durability (resistance to thermo-oxidative aging), which may be described as poor, corresponding to <50h.

[0451] In cases where a half-life figure is given to show nuances, this figure is rounded off to 25h, to take account of significant figures, linked to the precision of the evaluation.

[0452] Use as is: geometry, mechanical behavior and pollution characteristics suitable for installation on new vehicles. [0453] +: use as is is possible. [0454] ?: use as is is impossible.

[0455] Oligomers (insoluble extractables): this test consists in filling a tube with FAM B-type alcohol-blended gasoline at 60? C. for 96 hours, then emptying and filtering it into a beaker. The filter and the residue are dried until a constant mass is obtained, which must be less than or equal to 0.3 g/m.sup.2 (tube internal surface area).

TABLE-US-00001 TABLE 1 Oligomers Structure (mixture weight %) (insoluble thickness distribution of the layers Use extractables) Example (as a percentage of the total thickness) Aging as is (g/m.sup.2) CE1 Virgin single-layer gasoline line + + >0.3 CE2 ELV single-layer gasoline line ? ? <0.3 CE3 Virgin single-layer air transport line + + >0.3 CE4 ELV single-layer air transport line ? ? >0.3 CE5 Virgin three-layer gasoline line + + >0.3 CE6 ELV three-layer gasoline line ? ? <0.3 EI1 Ground ELV single-layer PA 11 PL gasoline +? + <0.3 line + ground ELV PA11 PL tank + PA 11 PL Mixture: (35/35/30)% EI2 Ground ELV single-layer PA11PL gasoline + + <0.3 line + PA11PL Mixture: (50/50)% EI3 PA11NX2//ground ELV three-layer gasoline + + <0.3 line//PA11NX2 Thickness distribution: 15/70/15% EI4 PA11NX2//ground ELV three-layer gasoline + + <0.3 line + PA610PL (mixture: (50/50)%)//PA11NX2 Thickness distribution: 15/70/15% EI5 PA11NX2//ground ELV PA11PL gasoline + + <0.3 line + ground ELV PA11PL tank (mixture: (50/50)%)//PA11NX2 Thickness distribution: 15/70/15% EI6 Ground ELV single-layer PA11PL air transport + + NT line + PA11PL (mixture: (50/50)%) EI7 Ground ELV single-layer PA12PL air transport + + NT line + PA12PL (mixture: (50/50)%) EI8 Ground ELV single-layer PA610PL air + + NT transport line + PA610PL (mixture: (50/50)%) EI9 Ground ELV single-layer PA612PL air + + NT transport line + PA612PL (mixture: (50/50)%) EI10 Ground ELV single-layer PA 12 PL gasoline + + NT line + ground ELV PA12 PL tank + PA 12 PL Mixture: (35/35/30)% EI11 Ground ELV single-layer PA 610 PL gasoline + + NT line + ground ELV PA610 PL tank + PA 610 PL Mixture: (35/35/30)% EI12 Ground ELV single-layer PA 612 PL gasoline + + NT line + ground ELV PA 612 PL tank + PA 612 PL Mixture: (35/35/30)% EI13 PA11/10TPL//ground ELV three-layer + + NT gasoline line + PA610PL (mixture: (50/50)%)//PA11/10TPL Thickness distribution: 15/70/15% CE1 to CE6: counter-examples EI1 to EI13: Examples of the invention NT: not tested

[0456] The following compositions were compounded on a Coperion/Werner 40 mm twin-screw extruder, 70 kgh, 300 rpm, 270? C. set point, with ?100 mmHg degassing. [0457] PA11PL is a virgin PA 11 containing 7% BBSA and 1% stabilizer. [0458] PA11NX2 is a virgin PA11 containing 10% PA610, 5% maleic anhydride functionalized EPR impact modifier and 1% stabilizer. [0459] PA12PL is a virgin PA 12 containing 7% BBSA and 1% stabilizer. [0460] PA11/10TPL is a virgin PA 11/10T (0.7/0.3) containing 7% BBSA and 1% stabilizer. [0461] PA610PL is a virgin PA610 containing 7% BBSA and 1% stabilizer. [0462] PA612PL is a virgin PA612 containing 7% BBSA and 1% stabilizer.

[0463] The following compositions are ground materials from tubes and tanks collected from ELVs in a scrapyard. [0464] ground ELV PA 11 PL gasoline line are chips of gasoline lines collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.02, a mole ratio of nitrile functions of 0.05, and a mole ratio of methyl functions of 0.004. [0465] ground ELV PA 12 PL gasoline line are chips of gasoline lines collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.02, a mole ratio of nitrile functions of 0.05, and a mole ratio of methyl functions of 0.004. [0466] ground ELV PA11 PL tank are chips of gasoline tanks collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.01, a mole ratio of nitrile functions of 0.02, a mole ratio of methyl functions of 0.002. [0467] ground ELV PA12 PL tank are chips of gasoline tanks collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.01, a mole ratio of nitrile functions of 0.02, a mole ratio of methyl functions of 0.002. [0468] ground ELV PA11PL air transport line are chips of brake pipes collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.04, a mole ratio of nitrile functions of 0.1, a mole ratio of methyl functions of 0.01. [0469] ground ELV PA12PL air transport line are chips of brake pipes collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.03, a mole ratio of nitrile functions of 0.09, a mole ratio of methyl functions of 0.008. [0470] ground ELV PA610PL air transport line are chips of brake pipes collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.02, a mole ratio of nitrile functions of 0.07, a mole ratio of methyl functions of 0.010. [0471] ground ELV PA612PL air transport line are chips of brake pipes collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.03, a mole ratio of nitrile functions of 0.08, a mole ratio of methyl functions of 0.009. [0472] ground ELV PA610PL gasoline line are chips of gasoline lines collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.01, a mole ratio of nitrile functions of 0.03 and a mole ratio of methyl functions of 0.001. [0473] ground ELV PA612PL gasoline line are chips of gasoline lines collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.01, a mole ratio of nitrile functions of 0.04, a mole ratio of methyl functions of 0.002. [0474] ground ELV PA610 PL tank are chips of gasoline tanks collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.009, a mole ratio of nitrile functions of 0.01, a mole ratio of methyl functions of 0.001. [0475] ground ELV PA612 PL tank are chips of gasoline tanks collected from ELVs with a mole ratio of primary amide functions relative to the secondary amide functions of 0.008, a mole ratio of nitrile functions of 0.02, a mole ratio of methyl functions of 0.001.

[0476] The mole ratio is determined as defined in the above text.

Multilayer Tubes of the Invention:

[0477] The layers are described from outside to inside, followed by their respective thicknesses indicated as a percentage; the tubes are 8?1 mm in size.

Preparation of the Multilayer Structures (Tubes):

[0478] The multilayer tubes are produced by coextrusion. A Maillefer multilayer extrusion industrial line is used, equipped with five extruders connected to a multilayer extrusion head with spiral mandrels.

[0479] The screws used are single extrusion screws having screw profiles adapted to the polyamides. In addition to the five extruders and the multilayer extrusion head, the extrusion line includes: [0480] a die-punch assembly, located at the end of the coextrusion head; the inside diameter of the die and the outside diameter of the punch are chosen as a function of the structure to be made and of the materials of which it is composed, and also as a function of dimensions of the tube and of the line speed; [0481] a vacuum tank with an adjustable level of vacuum. In this tank circulates water maintained in general at 20? C., into which is immersed a gauge for conforming the tube to its final dimensions. The diameter of the gauge is adapted to the dimensions of the tube to be made, typically from 8.5 to 10 mm for a tube with an outside diameter of 8 mm and a thickness of 1 mm; [0482] a succession of cooling tanks in which water is maintained at about 20? C., for cooling the tube along the path from the head to the drawing bench; [0483] a diameter measurer; [0484] a drawing bench.

[0485] The configuration with five extruders is used to make tubes ranging from 2 layers to 5 layers (and also single-layer tubes). In the case of the structures in which the number of layers is less than 5, several extruders are then fed with the same material.

[0486] Before the tests, in order to ensure the best properties for the tube and a good extrusion quality, it is verified that the extruded materials have a residual moisture content before extrusion of less than 0.08%. If this is not the case, an additional step of drying the material before the tests is carried out, generally in a vacuum dryer, overnight at 80? C.

[0487] The tubes, which meet the characteristics described in the present patent application, were taken, after stabilization of the extrusion parameters, the target dimensions of the tubes no longer changing over time. The diameter is monitored by a laser diameter measurer installed at the end of the line.

[0488] The line speed is typically 20 m/min. It generally varies between 5 and 100 m/min.

[0489] The speed of the extruder screws depends on the thickness of the layer and on the diameter of the screw, as is known to those skilled in the art.

[0490] In general, the temperatures of the extruders and tools (head and joint) should be set so as to be sufficiently higher than the melting point of the compositions under consideration, such that they remain in the molten state, thus preventing them from solidifying and blocking the machine. [0491] Virgin single-layer gasoline line is an 8?1 mm virgin single-layer gasoline line composed of PA11 PL. [0492] ELV single-layer gasoline line is an 8?1 mm single-layer gasoline line composed of PA11 PL collected from an end-of-life motor vehicle (ELV). [0493] Virgin three-layer gasoline line is an 8?1 mm virgin three-layer gasoline line, interior>PA11NX2//PA610 PL//PA11NX2<exterior, having the following thickness distributions: 15%/70%/15%. [0494] ELV three-layer gasoline line is an ELV 8?1 mm three-layer gasoline line, interior>PA11NX2//PA610 PL//PA11NX2<exterior, having the following thickness distributions: 15%/70%/15%.