Flexible plastic line, method for the production thereof, and uses of same

Abstract

A plastics line (1) is described with at least one layer (5) consisting of the following components: (A) 70-94 weight percent of a polyamide selected from the following group: polyamide 516, polyamide 616, polyamide 1016 or mixtures thereof; (B) 4-20 weight percent impact modifier; (C) 2-15 weight percent of plasticiser; (D) 0-5 weight percent of additives different from (B) and (C),
wherein the sum of (A)-(D) is 100 weight percent, and with the proviso that layer (5) does not contain polyamide 6,
as well as a method of manufacturing such a plastic pipe and uses of such a plastic pipe.

Claims

1. A plastics line with at least one layer consisting of the following components: (A) 70-94 weight percent of a polyamide selected from the group consisting of: polyamide 516, polyamide 616, polyamide 1016, or mixtures thereof; (B) 4-20 weight percent impact modifier; (C) 2-15 weight percent of plasticiser; (D) 0-5 weight percent of additives different from (B) and (C), wherein the sum of (A)-(D) is 100 weight percent, and with the proviso that said layer does not contain polyamide 6.

2. The plastics line according to claim 1, wherein the at least one impact modifier (B) is selected as an ethylene-α-olefin copolymer modified with an acid.

3. The plastics line according to claim 1, wherein the proportion of impact modifier (B) is in the range of 5-18 weight percent.

4. The plastics line according to claim 1, wherein the at least one plasticizer (C) is selected as at least one of a hydroxybenzoic acid ester and a sulfonamide-based plasticizer.

5. The plastics line according to claim 1, wherein the proportion of plasticizer (C) is in the range of 2-9 weight percent.

6. The plastics line according to claim 1, wherein the at least one polyamide (A) is selected as polyamide 616, and/or wherein the polyamide (A) has a relative solution viscosity, measured in m-cresol according to ISO 307 at a temperature of 20° C., in the range of 2.0-2.4, and/or wherein the at least one polyamide (A) has a melting point in the range of 175-240° C.

7. The plastics line according to claim 1, wherein the proportion of additives (D) is in the range of 0.1-3 weight percent, and/or wherein additives (D) are selected from the group consisting of: antioxidants, processing aids, UV stabilizers, heat stabilizers, pigments, masterbatch carriers, conductivity additives, lubricants, or mixtures thereof.

8. The plastics line according to claim 1, wherein the plastics line is a multilayer composite in the form of a hollow body enclosing an inner space, and said layer forms an outer layer, which closes off the multilayer composite to the outside.

9. The plastics line according to claim 8, wherein it consists of two or three layers, an inner layer adjoining the inner space, in the case of two layers the said outer layer adjoining the inner layer and in the case of three layers a middle layer adjoining the inner layer and the said outer layer adjoining the middle layer.

10. The plastics line according to claim 9, wherein the inner layer comprises a copper stabilization, in a proportion in the range of 0.01-0.10 weight percent, and/or in that the inner layer contains an impact modifier, wherein the weight percentages are each based on 100 weight percent of the material for producing the inner layer.

11. The plastics line according to claim 9, wherein the middle layer is formed on the basis of EVOH or consists of an EVOH.

12. The plastics line according to claim 9, wherein the inner layer comprises a copper stabilization, based on CuI, in a proportion in the range of 0.03-0.07 weight percent, and/or in that the inner layer contains an impact modifier, in a proportion in the range of 10-25 weight percent or in a range of 10-20 weight percent.

13. The plastics line according to claim 9, wherein the inner layer contains an impact modifier, being an ethylene/α-olefin copolymer grafted with an acid anhydride.

14. The plastics line according to claim 9, wherein the inner layer consists of: (A_I) Polyamide 6, having a relative solution viscosity measured in sulphuric acid according to ISO 307 at a temperature of 20° C. in the range 3.5-3.8, or in the range of 3.6-3.75; (B_I) 10-30 weight percent impact modifier; (C_I) 0.01-0.1 weight percent heat stabilizer, based on copper (I); (D_I) 0-1 weight percent of additives, selected from the group: conductivity additives, crystallization accelerators, processing aids, lubricants, and mixtures thereof; the sum of the components (A_I)-(D_I) adding up to 100 weight percent of the material for producing the inner layer.

15. The plastics line according to claim 9, wherein the middle layer is formed on the basis of EVOH or consists of an EVOH, with an ethylene content in the range of 20-25 weight percent, or in the range of 25-30 weight percent.

16. The plastics line according to claim 9, wherein the total wall thickness of the multilayer composite is in the range of 0.5-2.5 mm, or in the range of 0.75-1.5 mm.

17. The plastics line according to one of the preceding claim 1, wherein the layer has a thickness in the range of 0.3-0.6 mm, and, if present, the inner layer has a thickness in the range 0.3-0.6 mm, and, if present, the middle layer has a thickness in the range 0.05-0.2 mm.

18. The plastics line according to claim 1, wherein it is manufactured in an extrusion process, extrusion blow moulding, tandem extrusion or a sheathing process, or in a co-extrusion process.

19. The plastics line according to claim 1 in the form of a line which can be designed at least in sections as a corrugated tube, as a line for combustion engines.

20. The plastics line according to claim 1, wherein the at least one impact modifier (B) is selected as an ethylene/α-olefin copolymer grafted with an acid anhydride.

21. The plastics line according to claim 1, wherein the at least one impact modifier (B) is selected as an ethylene/butylene, ethylene/propylene, or ethylene-propylene/ethylene-butylene copolymer modified or grafted with an acid anhydride.

22. The plastics line according to claim 1, wherein the at least one impact modifier (B) is selected as an ethylene/α-olefin copolymer grafted with a maleic anhydride.

23. The plastics line according to claim 1, wherein the proportion of impact modifier (B) is in the range of 10-16 weight percent or in the range of 12-15 weight percent.

24. The plastics line according to claim 1, wherein the at least one plasticizer (C) is selected as a N-substituted sulfonamide plasticizer.

25. The plastics line according to claim 1, wherein the at least one plasticizer (C) is selected as BBSA.

26. The plastics line according to claim 1, wherein the proportion of plasticizer (C) is in the range of 4-8 weight percent or 4.5-6 weight percent.

27. The plastics line according to claim 1, wherein the polyamide (A) has a relative solution viscosity, measured in m-cresol according to ISO 307 at a temperature of 20° C., in the range of 2.05-2.35, and/or wherein the at least one polyamide (A) has a melting point in the range of 190-215° C. or 200-215° C.

28. The plastics line according to claim 1, wherein the proportion of additives (D) is in the range of 0.5-1 weight percent.

29. The plastics line according to claim 1, wherein it consists of two or three layers, an inner layer adjoining the inner space, in the case of two layers the said outer layer adjoining the inner layer and in the case of three layers a middle layer adjoining the inner layer and the said outer layer adjoining the middle layer, wherein the inner layer is based on polyamide 6, and wherein the middle layer is based on EVOH.

30. The plastics line according to claim 1, wherein the layer, when formed as an outer layer according to claim 9, has a thickness in the range of 0.3-0.6 mm, or in the range of 0.4-0.5 mm, and, if present, the inner layer has a thickness in the range 0.3-0.6 mm, or in the range 0.4-0.5 mm, and, if present, the middle layer has a thickness in the range 0.05-0.2 mm, or in the range 0.075-0.125 mm.

31. The plastics line according to claim 1, wherein it is manufactured in a continuous extrusion process, extrusion blow moulding, tandem extrusion or a sheathing process, or in the case of a plastic pipe according to claim 9, in a co-extrusion process.

32. The plastics line according to claim 1 in the form of a line which can be designed at least in sections as a corrugated pipe, as a line for combustion engines, in the automotive sector, for fuel, urea or coolant.

33. A method for producing a plastics line according to claim 1, wherein the at least one, or the two or three layers, are formed into a hollow body, in a continuous or discontinuous process.

34. A method for producing a plastics line according to claim 1, wherein the at least one, or in the case of a plastic pipe according to claim 9, the two or three layers, are formed into a pipe or a line or a container, in a continuous and/or discontinuous process, including in an extrusion blow moulding, a tandem extrusion, a sheathing process or a (co)extrusion process.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are described in the following on the basis of the drawings, which are for explanatory purposes only and are not to be interpreted restrictively. In the drawings shows:

(2) FIG. 1 a fuel line in a sectional view perpendicular to the direction of flow.

DESCRIPTION OF PREFERRED EMBODIMENTS

(3) FIG. 1 shows an exemplary fuel line 1 according to the invention in a cross-section transverse to the main direction of flow.

(4) The cross-sectional area can be constant over the main direction of travel, i.e. the pipe can have a substantially hollow cylindrical shape.

(5) However, the cross-sectional area can also vary over the main direction, for example in the form of a corrugated pipe.

(6) An interior 2 is enclosed by the pipe wall. The inner space 2 is first followed radially outwards by an inner layer 3, which borders on the inner space 2 with its inner surface 7 and delimits it. This inner layer is based on polyamide 6 without other polyamide components.

(7) Directly adjacent to the inner layer 3 without an intermediate adhesion promoter layer is a middle layer 4 in the sense of a barrier layer, which is based on EVOH.

(8) Directly adjacent to the outside of this middle layer 4 and again without an intermediate adhesion promoter layer is the outer layer 5, which is based on polyamide 616. The outer surface 6 of the outer layer 5 limits the line to the outside.

(9) Starting Materials Used:

(10) Polyamide 616 (outer layer): η.sub.rel=2.20 (0.5 weight percent in m-cresol); T.sub.m measured with DSC according to ISO 11357 (2011)=196° C.

(11) Polyamide 6 (inner layer): η.sub.rel=3.7 (1 weight percent in sulphuric acid); T.sub.m measured with DSC according to ISO 11357 (2011)=222° C.

(12) Polyamide 612 (outer layer, comparative example): η.sub.rel=2.3 (0.5 weight percent in m-cresol); T.sub.m measured with DSC according to ISO 11357 (2011)=215-220° C.

(13) Ethylene vinyl alcohol (barrier layer): An ethylene/vinyl alcohol copolymer (EVOH) was used as material for the barrier layer. Specifically, the design examples involved a product of the company KURARAY, which is available under the name EVAL® under the product code F170B and has an ethylene content of 27 mol %. It is available in Europe from EVAL Europe N.V. in Zwijindrecht, Belgium.

(14) Plasticizer (outer layer):

(15) BBSA (N-butylbenzenesulphonamide) was used as the plasticiser (WM). This is available, for example, under the brand name Uniplex 214, from Lanxess.

(16) Impact modifier (for inner and outer layer):

(17) Acid-modified ethylene/α-olefin copolymers were used as impact modifiers (SZM), namely ethylene-butylene copolymers grafted with maleic anhydride.

(18) Impact resistance modifier of the inner layer: MVR value (measured at 230° C./2.16 kg) of 1.2 g/10 min, DSC glass transition temperature, according to ISO standard 11357-2 (2013) of −65° C., available under the name Tafmer MH5020C from Mitsui Chemicals.

(19) Impact modifier of the outer layer: An olefinic impact modifier functionalized with maleic anhydride, blend of ethylene/propylene copolymer and ethylene/but-1-ene copolymer in a weight ratio of 67:33, grafted with 0.6 weight percent of maleic anhydride, MVR value 1.3 g/10 min (measured at 230° C./2.16 kg), DSC glass transition temperature, according to ISO standard 11357-2 (2013) of −60° C., available under the name Tafmer MC201 from Mitsui Chemicals.

(20) Copper stabilizer (inner layer):

(21) CuI/KI (1:6) was used as copper stabiliser in a proportion of 0.05 weight percent relative to the total mass of the inner layer. The copper (I) iodide, for example, is commercially available from the company William Blythe Ltd, and the potassium iodide from the company Liquichem Handelsgesellschaft mbH.

(22) Masterbatch (outer layer):

(23) Euthylene Black, soot-based (40%) colour masterbatch based on PE, available from BASF (Ludwigshafen, DE).

(24) Production of the Test Specimens:

(25) Pipes were co-extruded at mass temperatures between 210 and 260° C. under vacuum of −56 mbar and an extrusion speed of 32.8 m/min. Pipes with an outside diameter of 8 mm and a wall thickness of 1 mm were used as test specimens. The length of the pipe was adjusted according to the test requirements.

(26) The following tests were carried out on the described pipe structures: Unless otherwise stated or specified by the standard, the measurements were carried out at 50% relative humidity.

(27) Washing Out:

(28) Test according to SAE J2260 with test fuel FAM-B (according to SAE J1681 (2000))—test 96 hours, 60° C. sealed tube of 200 cm; maximum extract according to VW TL 52712 6 g/m.sup.2 and the upper limit of insoluble components is 0.7 g/m.sup.2.

(29) Zinc Chloride Test:

(30) Test on a test piece of 30 cm length, according to SAE J2260 (2004) paragraph 7.12.2, after 200 hours in 50% w/w ZnCl.sub.2 (aq.). A test for resistance to zinc chloride is considered passed as long as the pipe does not show any cracks or gaps after storage.

(31) Tensile Strength and Modulus of Elasticity:

(32) Have been measured according to ISO 527 at a tensile speed of 1 mm/min on an ISO 3167 compliant tensile bar.

(33) Pipe Tensile Tests:

(34) Pipe tensile tests were carried out according to ISO 527-2 (2012). Test specimens with a length of 150 mm (tensile tests in extrusion direction) or 10 mm (tensile tests transverse to extrusion direction) were used for tests. The test temperature is 23° C. and the test speed 100 mm/min (for tests in the direction of extrusion) or 25 mm/min if tests are carried out crosswise to the direction of extrusion.

(35) Specifically, the following measurements were carried out according to ISO 527:

(36) Elongation at max. tension (25 mm/min, transverse to extrusion direction), Maximum elongation stress (25 mm/min, transverse to extrusion direction), Elongation at max. tension (100 mm/min, in extrusion direction), Maximum elongation stress (100 mm/min, in extrusion direction).

(37) Otherwise, the tests were carried out in accordance with the minimum requirements of the Volkswagen TL 52712 standard (2016), the test temperature being 23° C., unless otherwise expressly specified by the standard (i.e. for cold impact, appearance, washout rate).

(38) Specifically, the following measurements were made according to TL 52712: breaking stress, transverse to the direction of extrusion (25 mm/min); elongation at break, transverse to the direction of extrusion (25 mm/min); yield stress, transverse to the direction of extrusion (25 mm/min); breaking stress in the direction of extrusion (100 mm/min), yield stress in the direction of extrusion (100 mm/min); elongation at break in the direction of extrusion (100 mm/min);

(39) Cold Behaviour:

(40) is tested in accordance with TL 52712 in line with VW standard PV 3905. The drop height of the ball is 65 cm. At least 10 test specimens are measured and the number of fractures is given in percent.

(41) Bursting Pressure:

(42) The bursting pressure of the manufactured mouldings is measured in accordance with DIN 73378 (1996) on hollow bodies with dimensions of 8 mm outside diameter and wall thickness of 1 mm.

(43) Relative Viscosity:

(44) DIN EN ISO 307 (2007), in 0.5 weight percent m-cresol solution or 1 weight percent sulphuric acid solution (polyamide 6) at a temperature of 20° C.

(45) Thermal Behavior

(46) (melting point Tm, melting enthalpy and glass transition temperature (Tg): ISO standard 11357-1 (2016), -2 (2013) and -3 (2011), granules, the differential scanning calorimetry (DSC) is performed at a heating rate of 20° C./min.

(47) TABLE-US-00001 TABLE 1 Compositions, in each case intermediate barrier layer of EVOH each with a thickness of 0.2 mm B1 VB1 Unit outer Inner outer Inner layer layer layer layer Layer Thickness mm 0.4 mm 0.4 mm 0.4 mm 0.4 mm polyamide 616 weight 72.15 — — — % polyamide 612 weight — — 71.9 — % polyamide 6 weight — 78.45 — 72.5 % SZM (Tafmer weight 18.0 — 18.0 20.0 MC201) % SZM (Tafmer weight — 20.0 — — MH5020C) % WM (BBSA) weight 8.0 — 10.0 6.0 % CuI/KI (1:6) weight — 0.05 — — % Black weight 1.25 1.4 — 1.4 masterbatch % Stabilizer* weight 0.6 0.1 0.1 0.1 % *0.1 wt. % MgStearate and 0.5 wt. % Hostanox PAR24, obtainable from Clariant;

(48) TABLE-US-00002 TABLE 2 Properties Property Standard Unit B1 VB1 breaking stress, transverse VW TL 52712 MPa 21 18 to the direction of extrusion Elongation at break, VW TL 52712 % 260 220 transverse to extrusion direction Elongation at max. strain ISO 527 % 248 235 across Maximum tension ISO 527 MPa 41 36 across Yield strength, transverse to VW TL 52712 MPa 37 32 extrusion direction Maximum strain, ISO 527 MPa 53 50 longitudinal Elongation at max. strain ISO 527 % 395 262 along Yield stress in extrusion VW TL 52712 MPa 33 28 direction Elongation at break in VW TL 52712 % 392 310 extrusion direction Bursting Pressure DIN 73378 bar 101 82 Cold shock, −40° C., 500 g VW TL 52712 % 0 40 Cold shock, −40° C., 880 g VW TL 52712 % 0 20 Appearance 96 h, 60° C., VW TL 52712 light strong flocculation FAM B flocculation Wash out quantity 96 h, VW TL 52712 mg/dm2 25 337 60° C., FAM B Zinc chloride resistance SAE J2260 No cracks Failed to pass FAM B: Test fuel according to SAE J1681 (2000)

(49) It can be seen from the test values that the excellent mechanical properties of the pipes using the moulding compound according to the invention as the outer layer represent a significant improvement over those using the comparative moulding compound as the outer layer. This applies to all mechanical properties and especially to the cold impact resistance.

(50) The washout resistance of the comparative test does not meet industrial requirements and the structure is not sufficiently resistant to zinc chloride. The suitability of the cable according to the invention for the application in the automotive sector is therefore impressively proven by the good mechanical properties as well as the wash-out quantity and the resistance to zinc chloride and is unexpected compared to the comparative example.

LIST OF REFERENCE SIGNS

(51) 1 Fuel line 2 Interior of 2 3 Inner layer 4 Middle layer 5 Outer layer 6 Outside surface of 1 7 Inner surface of 1