Adhesive composition and structure comprising at least one layer of said composition

Abstract

An adhesive composition including predominantly one or two polyamide(s) having units chosen from: at least one unit denoted A having an average number of carbon atoms per nitrogen atom, denoted C.sub.A, ranging from 4 to 8.5, advantageously from 4 to 7; at least one unit denoted B having an average number of carbon atoms per nitrogen atom, denoted C.sub.B, ranging from 7 to 10, advantageously from 7.5 to 9.5; and at least one unit denoted C having an average number of carbon atoms per nitrogen atom, denoted C.sub.C, ranging from 9 to 18, advantageously from 10 to 18, and to the use thereof.

Claims

1. A polyamide consisting of the following units: at least one unit denoted A with a mean number of carbon atoms per nitrogen atom, denoted C.sub.A, ranging from 4 to 8.5; at least one unit denoted B with a mean number of carbon atoms per nitrogen atom, denoted C.sub.B, ranging from 7 to 10; at least one unit denoted C with a mean number of carbon atoms per nitrogen atom, denoted C.sub.C, ranging from 9 to 18; and optionally at least one unit Z other than an amide unit; one of the units A, B or C being in very predominant proportion in the polyamide and representing from 80% to 97% by weight relative to the total weight of the polyamide, the mean number of carbon atoms per nitrogen atom of the units A, B and C also corresponding to the following strict inequality: C.sub.A<C.sub.B<C.sub.C, the heat of fusion of the polyamide being greater than 25 J/g (DSC), the melting point of the polyamide being greater than 150 C. (DSC), and wherein unit B is the very predominant unit in the polyamide.

2. The polyamide as claimed in claim 1, wherein the polyamide consists of only one unit A, only one unit B and only one unit C.

Description

EXAMPLES

1/When the Composition According to the Invention Comprises a Terpolyamide Consisting of Units A, B and C

(1) 1.1 Preparation of the Compositions

(2) The compositions according to the invention given in Table 1 were prepared from the following components. The amounts of products are expressed as weight percentages relative to the total weight of the composition.

(3) PA 6/6.12/12 (6%/88%/6%) denotes a copolyamide 6/6.12/12 of mass composition 6%/88%/6%, with an MFI at 235 C. under 5 kg of 5, a melting point of 188 C. and a heat of fusion of 55 J/g.

(4) PA 6/6.10/12 (6%/88%/6%) denotes a copolyamide 6/6.10/12 of mass composition 6%/88%/6%, with an MFI at 235 C. under 5 kg of 8, a melting point of 189 C. and a heat of fusion of 53 J/g.

(5) PA 6/6.12/12 (85%/5%/10%) denotes a copolyamide 6/6.12/12 of mass composition 85%/5%/10%, with an MFI at 235 C. under 5 kg of 6, a melting point of 189 C. and a heat of fusion of 55 J/g.

(6) PA 6/6.12/12/10.10 denotes a copolyamide 6/6.12/12/10.10 of mass composition 6%/88%/3%/3%, with an MFI at 235 C. under 5 kg of 6, a melting point of 186 C. and a heat of fusion of 50 J/g.

(7) PA 6.T/6.12/12 (6%/88%/6%) denotes a copolyamide 6.T/6.12/12 of mass composition 6%/88%/6%, with an MFI at 235 C. under 5 kg of 3.

(8) Stab1 denotes a mixture of organic stabilizers consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes and of 0.2% of phosphite Irgafos 168 from the company Ciba.

(9) EPR1 denotes a copolymer of ethylene and propylene of elastomeric nature functionalized with a group that is reactive with an anhydride function (at 0.5-1% by mass), with an MFI of 9 (at 230 C., under 10 kg), of Exxellor VA1801 type from the company Exxon used as impact modifier. Its flexural modulus is 10 MPa approximately according to standard ISO178.

(10) Plasticizing or BBSA denotes benzyl butyl sulfonamide (BBSA).

(11) The comparative compositions given in Table 2 were prepared from the following components.

(12) PA 6/6.10/12 (20%/20%/60%) denotes a copolyamide 6/6.10/12 of mass composition 20%/20%/60%, with an MFI at 235 C. under 5 kg of 5, a melting point of 128 C. and a heat of fusion of 23 J/g.

(13) PA 6/6.10/12 (18%/58%/24%) denotes a copolyamide 6/6.10/12 of mass composition 18%/58%/24%, with an MFI at 235 C. under 5 kg of 5, a melting point of 144 C. and a heat of fusion of 42 J/g.

(14) PA 6/6.10/12 (60%/10%/30%) denotes a copolyamide 6/6.10/12 of mass composition 60%/10%/30%, with an MFI at 235 C. under 5 kg of 6, a melting point of 149 C. and a heat of fusion of 42 J/g.

(15) 1.2 Formation of the Pipes

(16) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm. These pipes 1 mm thick are constituted in the following manner:

(17) Outer layer of PA12-TL of 450 m/binder layer of 50 m/inner layer of PA6a.

(18) The definitions of PA12-TL and PA6a are as follows:

(19) PA6a denotes a composition based on polyamide 6 with an Mn (number-average molecular mass) of 28 000, containing 10% of plasticizer BBSA (benzyl butyl sulfonamide), 12% of functionalized EPR Exxelor VA1803 (from the company Exxon) and 1.2% of organic stabilizers consisting of 0.8% of phenol (Lowinox 44B25 from the company Great Lakes), 0.2% of phosphite (Irgafos 168 from the company Ciba) and 0.2% of anti-UV agent (Tinuvin 312 from the company Ciba). The melting point of this composition is 215 C.

(20) PA12-TL denotes a composition based on polyamide 12 with an Mn (number-average molecular mass) of 35 000, containing 6% of plasticizer BBSA (benzyl butyl sulfonamide), 6% of anhydride-functionalized EPR Exxelor VA1801 (from the company Exxon), and 1.2% of organic stabilizers consisting of 0.8% of phenol (Lowinox 44B25 from the company Great Lakes), 0.2% of phosphite (Irgafos 168 from the company Ciba) and 0.2% of anti-UV agent (Tinuvin 312 from the company Ciba). The melting point of this composition is 175 C.

(21) 1.3 Evaluation of the Pipes

(22) The adhesion was measured on these multilayers before and after immersion in hot biofuel.

(23) ADH1 corresponds to the measurement of the adhesion force expressed in N/cm.

(24) This is reflected by the measurement of the peel force, expressed in N/cm, and measured on the tube before it has been subjected to 15 days of conditioning at 50% relative humidity at 23 C. The given value concerns the weakest interface, i.e. the interface that is the least adherent of the multilayer, where there is the greatest risk of detachment. The peeling is performed at the interface by subjecting one of the parts to traction at an angle of 90 and at a speed of 50 mm/min.

(25) VG=very good, >80

(26) G=good, between 80 and >60

(27) QG=quite good (acceptable), between 60 and >30

(28) P=poor, between 30 and 10

(29) VP<10=very poor

(30) ADH2 corresponds to the measurement of the adhesion force after the test in biofuel, expressed in N/cm

(31) Same test as for the measurement of ADH1 described above, except that the interior of the pipe is filled with a biofuel E50 at 80 C. for 200 hours. The biofuel E50 is a mixture comprising by mass 50% of ethanol, 44% of gasoline L, 5% of water and 1% of methanol according to standard B31 5220 from the company Peugeot SA, the gasoline known as L being the reference lead-free gasoline of the Euro standard, referenced under the code E-H-003. These test conditions are much more severe than the preceding ones. The assessment criteria take this into account and are:

(32) G=good, >30

(33) QG=quite good (acceptable), >20 to <=30

(34) P=poor, >10 to <=20

(35) VP=very poor, <=10

(36) The results are given in Tables 1 and 2 below.

(37) Table 1 comprises compositions 1 to 6 according to the invention.

(38) TABLE-US-00001 TABLE 1 11 12 13 14 15 16 PA 6/6.12/12 100 89 (6%/88%/6%) PA 6/6.10/12 89 (6%/88%/6%) PA 6/6.10/12 89 (85%/5%/10%) PA 6/6.12/12/10.10 89 (6%/88%/3%/3%) PA 6.T/6.12/12 89 (6%/88%/6%) EPR1 10 10 10 Plasticizer 10 10 BBSA Stab1 1 1 1 1 1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 58 65 61 33 61 66 ADH2 >30 >30 >30 >30 >30 >30

(39) Table 2 comprises comparative compositions C1 to C3.

(40) TABLE-US-00002 TABLE 2 C1 C2 C3 PA 6/6.10/12 89 (20%/20%/60%) PA 6/6.10/12 89 (18%/58%/24%) PA 6/6.10/12 89 (60%/10%/30%) EPR1 10 Plasticizer 10 10 BBSA Stab1 1 1 1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 47 44 45 ADH2 <10 <10 <10

(41) Compositions 1, 2, 3, 4, 5 and 6 give satisfactory results in terms of adhesion between the layer of PA12 and the layer of PA6, when compared with the results obtained with the comparative compositions.

(42) Specifically, it was observed that the adhesion (denoted ADH2) obtained with comparative compositions C1, C2 and C3 becomes insufficient after contact with biofuel gasoline.

2/When the Composition According to the Invention Comprises a Mixture of Two Copolyamides Consisting of Units A, B and C

(43) 2.1 Preparation of the Compositions

(44) The compositions according to the invention given in Table 3 were prepared from the following components. The amounts of products are expressed as weight percentages relative to the total weight of the composition.

(45) PA 6/6.12 (90%/10%) denotes a copolyamide 6/6.12 of mass composition 90%/10%, with an MFI at 235 C. under 5 kg of 7, a melting point of 199 C. and a heat of fusion of 58 J/g.

(46) PA 6.12/12 (10%/90%) denotes a copolyamide 6.12/12 of mass composition 10%190%, with an MFI at 235 C. under 5 kg of 7, a melting point of 163 C. and a heat of fusion of 38 J/g.

(47) PA 6/6.12 (10%/90%) denotes a copolyamide 6/6.12 of mass composition 10%/90%, with an MFI at 235 C. under 5 kg of 5, a melting point of 187 C. and a heat of fusion of 58 J/g.

(48) PA 6.12/12 (90%/10%) denotes a copolyamide 6.12/12 of mass composition 90%/10%, with an MFI at 235 C. under 5 kg of 6, a melting point of 185 C. and a heat of fusion of 52 J/g.

(49) PA 10.T/10.10 (80/20%) denotes a copolyamide 10.T/10.10 of mass composition 80/20%, with an inherent viscosity of 1.10, a melting point Tm of 292 C. and a heat of fusion of 49 J/g.

(50) The comparative composition given in Table 3 was prepared from the following components.

(51) PA 6/6.12 (50%/50%) denotes a copolyamide 6/6.12 of mass composition 50%/50%, with an MFI at 235 C. under 5 kg of 5, a melting point of 148 C. and a heat of fusion of 24 J/g.

(52) PA 6.12/12 (50%/50%) denotes a copolyamide 6.12/12 of mass composition 50%/50%, with an MFI at 235 C. under 5 kg of 4, a melting point of 143 C. and a heat of fusion of 24 J/g.

(53) 2.2 Formulations of the Pipes

(54) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm in a manner strictly similar to that of point 1.2.

(55) 2.3 Evaluation of the Pipes

(56) The adhesion was measured on these multilayers before and after immersion in hot biofuel, in a manner strictly similar to that of point 1.3.

(57) The compositions and results are given in Table 3 below.

(58) TABLE-US-00003 TABLE 3 21 22 23 24 25 C21 PA 6/6.12 44.5 50 50 (90%/10%) PA 6.12/12 44.5 50 (10%/90%) PA 6/6.12 50 60 (10%/90%) PA 6.12/12 50 50 (90%/10%) PA 6/6.12 50 (50%/50%) PA 10.T/10.10 40 (80%/20%) PA 6.12/12 50 (50%/50%) EPR1 10 Stab1 1 Evaluation of the adhesion between the outer layer (made of PA 12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 71 80 68 38 37 73 ADH2 >30 >30 >30 >30 >30 <10

(59) Compositions 21, 22, 23, 24 and 25 give satisfactory results in terms of adhesion between the layer of PA12 and the layer of PA6, when compared with the results obtained with comparative composition C21.

(60) Specifically, it was observed that the adhesion (denoted ADH2) obtained with comparative composition C21 becomes insufficient after contact with the hot biofuel gasoline.

3/When the Composition According to the Invention Comprises a Mixture of a Copolyamide and of a Homopolyamide Consisting of Units A, B and C

(61) 3.1 Preparation of the Compositions

(62) The compositions according to the invention given in Table 4 were prepared from the following components. The amounts of products are expressed as weight percentages relative to the total weight of the composition.

(63) PA12 denotes polyamide 12 with an inherent viscosity of 1.65. Its melting point is 178 C. and its heat of fusion is 54 kJ/kg.

(64) PA6 denotes a polyamide 6 of Mn (number-average molecular mass) 28 000. Its melting point is 220 C. and its heat of fusion is 68 kJ/kg.

(65) The comparative compositions given in Table 5 were prepared from the following components.

(66) PA 6/12 (50%/50%) denotes a copolyamide 6/12 of mass composition 50%/50%, with an MFI at 235 C. under 5 kg of 4, a melting point of 144 C. and a heat of fusion of 22 J/g.

(67) PA6.12 denotes polyamide 6.12 of Mn (number-average molecular mass) 29 000. Its melting point is 218 C. and its heat of fusion is 67 kJ/kg.

(68) 3.2 Formulations of the Pipes

(69) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm, in a manner strictly similar to that of point 1.2.

(70) 3.3 Evaluation of the Pipes

(71) The adhesion was measured on these multilayers before and after immersion in hot biofuel, in a manner strictly similar to that of point 1.3.

(72) The compositions according to the invention and results are given in Table 4 below.

(73) TABLE-US-00004 TABLE 4 31 32 33 34 PA 6/6.12 50 60 (90%/10%) PA 12 39 40 40 PA 6 50 PA 6.12/12 50 (10%/90%) PA 6/6.12 60 (10%/90%) EPR1 10 Stab1 1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 49 46 46 40 ADH2 >30 >30 >30 >30

(74) The comparative compositions and results are given in Table 5 below.

(75) TABLE-US-00005 TABLE 5 Without binder C31 C32 PA 12 40 PA 6/12 60 40 (50%/50%) PA6.12 60 EPR1 Stab1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 <5 45 63 ADH2 <5 <10 <10

(76) Compositions 31, 32, 33 and 34 give satisfactory results in terms of adhesion between the layer of PA12 and the layer of PA6, when compared with the results obtained with the comparative compositions.

(77) Specifically, it was observed that the adhesion (denoted ADH2) becomes insufficient after contact with hot biofuel gasoline.

4/Various Comparative Examples

(78) 4.1 Preparation of the Comparative Compositions

(79) The comparative compositions given in Table 6 were prepared from the following components. The amounts of products are expressed as weight percentages relative to the total weight of the composition.

(80) PA6.10 denotes a polyamide 6.10 of Mn (number-average molecular mass) 30 000 and having an excess of NH.sub.2 amine chain ends relative to the COOH chain ends, the concentration of NH.sub.2 chain ends being 45 eq/g. Its melting point is 223 C. and its heat of fusion is 61 kJ/kg.

(81) Binder coPA denotes a composition based on 50% copolyamide 6/12 (of 30/70 mass ratio) of Mn 16 000, and 50% copolyamide 6/12 (of 70/30 mass ratio) of Mn 16 000.

(82) Binder PPg denotes a composition based on PP (polypropylene) grafted with maleic anhydride, known under the name Admer QF551A from the company Mitsui.

(83) Binder PA6.10+PA6 denotes a composition based on PA6.10 obtained by polycondensation of hexanediamine with decanedioic acid (of Mn 30 000, and as defined elsewhere) and 36% of PA6 (of Mn 28 000, and as defined elsewhere); the mass-weighted mean of the heats of fusion is 63.5 J/g and the heat of fusion of the PA6 is 220 C.; and 1.2% of organic stabilizers (consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes, 0.2% of phosphite Irgafos 168 from the company Ciba and 0.2% of anti-UV agent 15, Tinuvin 312 from the company Ciba).

(84) Binder PA6.12+PA6 denotes a composition based on PA6.12 obtained by polycondensation of hexanediamine with dodecanedioic acid (of Mn 29 000, and as defined elsewhere) and 36% of PA6 (of Mn 28 000, and as defined elsewhere) and 1.2% of organic stabilizers (consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes, 0.2% of phosphite Irgafos 168 from the company Ciba and 0.2% of anti-UV agent Tinuvin 312 from the company Ciba).

(85) Binder PA6.10+PA12 denotes a composition based on PA6.10 obtained by polycondensation of hexanediamine with decanedioic acid (of Mn 30 000, and as defined elsewhere) and 36% of PA12 (of Mn 35 000, and as defined elsewhere) and 1.2% of organic stabilizers (consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes, 0.2% of phosphite Irgafos 168 from the company Ciba and 0.2% of anti-UV agent Tinuvin 312 from the company Ciba).

(86) Binder PA6+PA12+imod denotes a composition based on 40% PA6 (of Mn 28 000), 40% of PA12 (of Mn) and 20% of functionalized EPR Exxelor VA1801 (from the company Exxon) and 1.2% of organic stabilizers (consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes, 0.2% of phosphite Irgafos 168 from the company Ciba and 0.2% of anti-UV agent Tinuvin 312 from the company Ciba).

(87) PA6.12 denotes polyamide 6.12 obtained by polycondensation of hexanediamine with dodecanedioic acid of Mn (number-average molecular mass) 29 000. Its melting point is 218 C. and its heat of fusion is 67 kJ/kg.

(88) 4.2 Formulations of the Pipes

(89) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm, in a manner strictly similar to that of point 1.2.

(90) 4.3 Evaluation of the Pipes

(91) The adhesion was measured on these multilayers before and after immersion in hot biofuel, in a manner strictly similar to that of point 1.3.

(92) The comparative compositions and results are given in Table 6 below.

(93) TABLE-US-00006 TABLE 6 C41 C42 C43 C44 C45 C46 C47 Binder coPA 100 Binder PPg 100 Binder PA6.10 + PA6 100 Binder PA6.12 + PA6 100 Binder PA6.10 + 100 PA12 Binder PA6 + PA12 + 100 imod PA6.12 100 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of PA6a) of the multilayer pipe ADH1 >60 >60 26 28 29 22 18 ADH2 <10 <10 14 16 18 20 11

5/Use of the Compositions as Binder for Other Types of Multilayer Structure Based on Polyphthalamide

(94) 5.1 Preparation of the Compositions

(95) The compositions used are those described above.

(96) 5.2 Formulations of the Pipes

(97) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm.

(98) The multilayer structure of these examples is of the following nature: outer layer of PA12-TL of 450 m/binder layer of 50 m/inner layer of PPAb.

(99) The purpose of the binder here is to afford adhesion between the PA12 layer and the layer of polyphthalamide of 6.T/6 type, since the latter do not naturally adhere to each other.

(100) PPAb denotes a composition based on polyphthalamide of copolyamide 6.T/6 type Ultramid TKR4351 from the company BASF, and 25% of functionalized EPR Exxelor VA1803 (from the company Exxon), and 0.5% of stabilizer based on copper and potassium iodide of Iodide P201 type (from the company Ciba). The melting point of this composition is 295 C.

(101) 5.3 Evaluation of the Pipes

(102) The adhesion was measured on these multilayers before and after immersion in hot biofuel, in a manner strictly similar to that of point 1.3.

(103) The compositions according to the invention and comparative compositions and the results are given in Table 7 below.

(104) TABLE-US-00007 TABLE 7 11 12 21 31 C11 PA 6/6.12/12 100 89 (6%/88%/6%) PA 6/6.12 44.5 50 (90%/10%) PA 6.12/12 44.5 (10%/90%) PA 12 39 PA 6/6.10/12 89 (20%/20%/60%) EPR1 10 10 10 10 Stab1 1 1 1 1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and inner layer (made of polyphthalamide PPAb) of the multilayer pipe ADH1 55 68 65 51 49 ADH2 >30 >30 >30 >30 <10

(105) It is found that good adhesion values are also obtained between the layer of PA12 and the layer of polyphthalamide of PA6.T/6 type, especially after exposure to biofuel, in contrast with the comparative examples.

6/Use of the Compositions as Binder for Other Types of Multilayer Structure Based on EVOH

(106) 6.1 Preparation of the Compositions

(107) The compositions used are those described above.

(108) 6.2 Formulations of the Pipes

(109) These compositions are then used as binder layer for a multilayer pipe with an outside diameter of 8 mm and an inside diameter of 6 mm. The pipes are made by coextrusion of the compositions in the melt, i.e. above their melting point.

(110) The multilayer structure of these examples is now of the following nature: outer layer of PA12-TL of 425 m/binder layer of 50 m/layer of EVOH of 100 m/inner layer of PA6a of 425 m.

(111) The purpose of the binder here is to afford adhesion between the PA12 layer and the EVOH layer, since the latter do not naturally adhere to each other.

(112) EVOH denotes a copolymer of ethylene vinyl alcohol, for example Soarnol DC3203RB from the company Nippon Gosei. The melting point of this composition is 183 C.

(113) 6.3 Evaluation of the Pipes

(114) The adhesion was measured on these multilayers before and after immersion in hot biofuel, in a manner strictly similar to that of point 1.3.

(115) The compositions according to the invention and comparative compositions and the results are given in Table 8 below.

(116) TABLE-US-00008 11 12 21 31 C13 C21 C31 PA 6/6.12/12 100 89 (6%/88%/6%) PA 6/6.12 44.5 50 (90%/10%) PA 6.12/12 44.5 (10%/90%) PA 12 39 40 PA 6/6.10/12 89 (60%/10%/30%) PA 6/6.12 50 (50%/50%) PA 6.12/12 50 (50%/50%) PA 6/12 60 EPR1 10 10 10 BBSA 10 Stab1 1 1 1 1 Evaluation of the adhesion between the outer layer (made of PA12-TL) and the EVOH layer of the multilayer pipe ADH1 44 49 59 50 70 64 42 ADH2 >30 >30 >30 >30 <10 <10 <10

(117) It is observed that good adhesion values are also obtained between the layer of PA12 and the layer of EVOH, especially after exposure to biofuel, in contrast with the comparative examples.

7/Example of a Process for Manufacturing Multilayer Structures

In the Case of Pipes

(118) Multilayer pipes are made by coextrusion. A McNeil multilayer extrusion industrial line is used, equipped with 5 extruders connected to a multilayer extrusion head with spiral mandrels.

(119) The screws used are single extrusion screws having screw profiles adapted to the polyamides. In addition to the 5 extruders and the multilayer extrusion head, the extrusion line comprises: 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 pipe and of the line speed; 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 pipe to its final dimensions. The diameter of the gauge is adapted to the dimensions of the pipe to be made, typically from 8.5 to 10 mm for a pipe with an outside diameter of 8 mm and a thickness of 1 mm; a succession of cooling tanks in which water is maintained at about 20 C., for cooling the pipe along the path from the drawing head to the drawing bench; a diameter measurer; a drawing bench.

(120) The configuration with 5 extruders is used to make pipes ranging from 2 layers to 5 layers. 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.