COMPOSITION CONTAINING POLYAMIDE FOR COOLANT PIPES

Abstract

The invention relates to the use of a composition comprising at least one polyamide, at least one of said polyamides being a semi-crystalline copolyamide comprising at least one minority monomer unit resulting from the polycondensation of at least one diamine with at least one polymerised fatty acid, particularly a fatty acid dimer, or at least one diamine dimer with at least one dicarboxylic acid, or at least one amino acid dimer, or the mixtures thereof, as a sealing layer in a pipe containing a cooling liquid.

Claims

1. A sealing layer in a pipe, wherein said sealing layer composition comprises at least one polyamide, said polyamide is a semi-crystalline copolyamide comprising at least one minority monomer unit coming from the polycondensation: of at least one diamine with at least one polymerized fatty acid, or of at least one diamine dimer with at least one dicarboxylic acid, or of at least one amino acid dimer.

2. The sealing layer in a pipe according to claim 1, wherein said minority monomer unit comprises at least one of the following formulas: either the residue of a fatty acid dimer having the following formula (I): ##STR00052## or the residue of a diamine dimer having the following formula (II): ##STR00053## or the residue of an amino acid dimer having the following formula (III): ##STR00054## or a mixture thereof, wherein, independently of each other: n is comprised from 1 to 10, p is comprised from 1 to 10, ##STR00055## corresponds to a structure chosen from: ##STR00056##  m being comprised from 1 to 5 wherein R.sub.1 and R.sub.2 represent, independently of each other, H or a C.sub.1 to C.sub.12 alkyl chain, and ##STR00057## wherein R.sub.1 and R.sub.2 are cyclized to form a structure: i) with a ring of type cyclohexane ##STR00058## or phenyl: ##STR00059## ii) with two rings of 1,2,3,4-tetrahydronaphthalene type ##STR00060## or of bicyclo[4.4.0]decane type: ##STR00061## R.sub.3 and R.sub.4 being in the structures of one or two rings of C1 to C10 alkyl residues, or a mixture thereof, the total number of carbon atoms in the diacid having formula (I), the diamine having formula (II) and the amino acid having formula (III) being greater than or equal to 30.

3. The sealing layer in a pipe according to claim 1, wherein the pipe is a flexible pipe.

4. The sealing layer in a pipe according to claim 1, wherein the copolyamide is an aliphatic copolyamide.

5. The sealing layer in a pipe according to claim 1, wherein the viscosity in solution of said sealing layer composition, as determined according to ISO standard 307:2007 in m-cresol at a temperature of 20° C., is greater than 1.

6. The sealing layer in a pipe according to claim 1, wherein the Tm of the composition is greater than 170° C., as determined according to ISO standard 11357-3:2013 at a rate of 20 K/min in DSC.

7. The sealing layer in a pipe according to claim 1, wherein at least one of the other monomer units of said copolyamide is a monomer unit A selected from the group consisting of a monomer unit obtained from a C.sub.6 to C.sub.12 amino acid, a monomer unit obtained from a C.sub.6 to C.sub.12 lactam, and a monomer unit having the formula (aliphatic diamine Ca).(aliphatic diacid Cb), with a representing the number of carbon atoms in the diamine and b representing the number of carbon atoms in the diacid, a and b each being inclusively between 4 and 22.

8. The sealing layer in a pipe according to claim 1, wherein the molar proportion of said at least minority monomer unit in the semi-crystalline copolyamide is from 1 to 20%, relative to the sum of all the monomer units of said copolyamide.

9. The sealing layer in a pipe according to claim 2, wherein said minority monomer unit is a monomer unit X.diacid having formula (I), X being an aliphatic diamine.

10. The sealing layer in a pipe according to claim 9, wherein ##STR00062## as defined in formulas (I), (II) and (III) corresponds to ##STR00063##

11. The sealing layer in a pipe according to claim 9, wherein the polymerized fatty acid comprises a fatty acid dimer in proportions of at least 75% by weight.

12. The sealing layer in a pipe according to claim 9, wherein the number of carbons in diamine X is greater than 8.

13. The sealing layer in a pipe according to claim 7, wherein the monomer unit A is a monomer unit obtained from the polycondensation of a lactam or an amino acid.

14. The sealing layer in a pipe according to claim 7, wherein the monomer unit A is a monomer unit obtained from the polycondensation of a Ca aliphatic diamine and a Cb aliphatic dicarboxylic acid.

15. The sealing layer in a pipe according to claim 14, wherein the monomer unit A is selected from the group consisting of PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1210, PA1212, PA1214, and PA1218.

16. The sealing layer in a pipe according to claim 7, wherein the composition comprises a polyamide selected from the group consisting of an aliphatic, cycloaliphatic and aromatic polyamide, and said at least one semi-crystalline polyamide.

17. The sealing layer in a pipe according to claim 16, wherein said polyamide is an aliphatic or cycloaliphatic polyamide identical to monomer unit A of said semi-crystalline polyamide.

18. The sealing layer in a pipe according to claim 1, wherein the composition further comprises at least one additive selected from the group consisting of a polyolefin, and a plasticizer, or a mixture thereof.

19. (canceled)

20. The sealing layer in a pipe according to claim 1, wherein the composition further comprises at least one additive.

21. The sealing layer in a pipe according to claim 1, wherein the composition comprises by weight: 50 to 99.9% by weight of said semi-crystalline copolyamide optionally comprising from 0 to 70% by weight of another polyamide relative to said semi-crystalline copolyamide, 0.1 to 50% by weight of a polyolefin comprising an epoxy, anhydride or acid function, introduced by grafting or by copolymerization, and 0 to 10% by weight, of a plasticizer, 0 to 10%, by weight, of an additive, the sum of the different constituents of the composition being equal to 100%.

22. A pipe, for transporting a cooling liquid comprising at least one sealing layer (1) obtained from a composition as defined according to claim 1.

23. A composition comprising by weight: 57 to 85% of a semi-crystalline copolyamide as defined in claim 1, optionally comprising from 0 to 70% by weight of another polyamide, from 12 to 40% by weight of a polyolefin comprising an epoxy, anhydride or acid function, introduced by grafting or by copolymerization, from 3 to 10% by weight by weight, of a plasticizer, and from 0 to 10%, by weight, the sum of the different constituents of the composition being equal to 100%.

24. The composition according to claim 23, wherein said other polyamide is selected from the group consisting of an aliphatic polyamide, PA11, and PA12.

25. The composition according to claim 23, wherein said copolyamide is a semi-crystalline copolyamide comprising at least one minority monomer unit having at least one of the following formulas: either the residue of a fatty acid dimer having the following formula (I): ##STR00064## or the residue of a diamine dimer having the following formula (II): ##STR00065## or the residue of an amino acid dimer having the following formula (III): ##STR00066## or a mixture thereof, wherein, independently of each other: n is comprised from 1 to 10, p is comprised from 1 to 10, ##STR00067## corresponds to a structure chosen from: ##STR00068##  m being comprised from 1 to 5 wherein R.sub.1 and R.sub.2 represent, independently of each other, H or a C.sub.1 to C.sub.12 alkyl chain, and ##STR00069## wherein R.sub.1 and R.sub.2 are cyclized to form a structure: i) with a ring of type cyclohexane: ##STR00070## or phenyl: ##STR00071## ii) with two rings of 1,2,3,4-tetrahydronaphthalene type ##STR00072## or of bicyclo[4.4.0]decane type: ##STR00073## R.sub.3 and R.sub.4 being in the structures of one or two rings of C1 to C10 alkyl residues, or a mixture thereof, the total number of carbon atoms in the diacid having formula (I), the diamine having formula (II) and the amino acid having formula (III) being greater than or equal to 30.

26. The composition according to claim 23, wherein said semi-crystalline copolyamide comprises a monomer unit X.diacid having formula (I), X being an aliphatic diamine.

27. The sealing layer in a pipe according to claim 1, wherein said sealing layer comprises at least one polyamide, wherein said polyamide is a semi-crystalline copolyamide comprising at least one minority monomer unit coming from the polycondensation: of at least one diamine with at least one polymerized fatty acid, particularly a fatty acid dimer, or of at least one diamine dimer with at least one dicarboxylic acid, or mixtures thereof.

Description

DESCRIPTION OF THE FIGURES

[0302] FIG. 1 shows the hydrolysis at 130° C. pH4 of molded parts obtained from the different compositions formulated in Table III.

[0303] The residual lengthening is about 2 times as high at equal aging. The lifetime for reaching a break on lengthening of 50% (usual criterion) is clearly higher.

[0304] The extruded part obtained with the formulated composition of the invention with Pripol 1009 therefore has very obviously improved resistance to hydrolysis compared with a part obtained with a formulation containing PA11.

[0305] X-axis: aging duration in hours

[0306] Y-axis: Break on lengthening (%)

[0307] Upper curve: FI2

[0308] Middle curve: FI1

[0309] Lower curve: FC1

EXAMPLES

1. Preparation of a Polymer of the Composition According to the Invention

[0310] The following compositions were prepared

TABLE-US-00001 TABLE I Polyamide and C1 I1 Molar composition PA11 PA11/10.Pripol 1009 19/1 unit Terephthalic acid — — kg 11-Undecanoic 29 27.62 kg amino acid Decanediamine — 1.26 kg Sebacic acid — — kg Pripol 1009 — 4.12 kg BisHMTA — — kg N-heptylamino-11- — — kg undecanoic acid Deionized water 8 4 kg H.sub.3PO.sub.4 85% 20.4 23.3 g

[0311] The Pripol 1009 used has a hydroxyl index IOH=196 mg KOH/g, which gives an equivalent molar mass of 572.6 g/mol.

[0312] Pripol 1009 is constituted of: ≥98.5% of dimer, ≤1% of trimer, ≤1% of 1½ mer and ≤0.1% of monomer.

[0313] The synthesis conditions were as follows:

[0314] After charging, the 100 liter autoclave reactor is deoxygenated by sequences of nitrogen pressurization then release. The reactor's content is heated to 240° C. under autogenous pressure and with stirring then held for 1 h in these conditions. The reactor is then relaxed to a pressure of 0.2 bar relative in 2 hours then held for 30 minutes in these conditions. The polymer obtained is then unloaded from the reactor in the form of rods and then in the form of granules.

[0315] The polymers have the following characteristics:

TABLE-US-00002 TABLE II C1 I1 Composition PA11 PA11/10.Pripol 1009 19/1 Acidity (meq/g) 0.05 0.056 Basicity (meq/g) 0.038 0.04 Inherent viscosity 1.45 1.41 m-cresol (dL/g) Tm (° C.) 189 174 Tc (° C.) 155 145 Enthalpy of 60 48 crystallization (J/g) Tg (° C.) 48 31

[0316] Inherent viscosity is measured in m-cresol according to ISO standard 307:2007 but while changing the solvent (use of m-cresol instead of sulfuric acid and the temperature being 20° C.).

[0317] The crystallization enthalpy of said polymer matrix is measured using differential scanning calorimetry (DSC) according to ISO standard 11357-3:2013. The heating and cooling rates are 20° C./min.

[0318] The Tm and Tc are measured by differential scanning calorimetry (DSC) according to ISO standard 11357-3:2013. The heating and cooling rates are 20° C./min.

[0319] The Tg is measured by differential scanning calorimetry (DSC) according to ISO standard 11357-2:2013. The heating and cooling rates are 20° C./min.

[0320] The Mn of the thermoplastic polymer is determined from the titration (assay) of the terminal functions according to a potentiometric method (direct assay of acids or bases)

2. Preparation of Formulated Compositions

[0321] The following formulations were prepared (Table III)

TABLE-US-00003 TABLE III Formulation Formulation FC1 Invention Invention % by FI1 % by FI2 % by reference weight weight weight C1 67.9 I1 67.9 82.9 Lotader 4700 24 24 Lotader AX8900 4 4 Escor 5000 2 2 Orevac IM 800 15 MM euthylen black 0.9 0.9 0.9 6005 C4 ANOX ® NDB TL89 1.2 1.2 1.2

[0322] Escor® 5000: polyolefin (ethylene-functionalized maleic acrylic acid copolymer) sold by Exxon.

[0323] Orevac® IM800: polyolefin (ethylene-functionalized maleic anhydride copolymer) sold by Arkema.

[0324] Lotader 4700: ethylene, acrylic ester and maleic anhydride terpolymer sold by Arkema.

[0325] Lotader AX8900: ethylene, acrylic ester and glycidyl methacrylate terpolymer sold by Arkema MM euthylen black 6005 C4: master black mixture sold by BASF.

[0326] ANOX® NDB TL89: phenol phosphite organic stabilizer sold by Chemtura.

[0327] These experiments were conducted on the HAAKE 2-9 screw profile.

[0328] The compounding flow rate was 2.2 kg/hr for a screw rate of 300 rpm and a flat temperature profile at 270° C.

3. Hold Upon Cooling (Hydrolysis) at 130° C. of Molded Parts Obtained from the Compositions in Table III.

3.1 Preparation of Molded Parts

[0329] ISOR 527 1BA dumbbells

3.2 Hydrolysis Test Protocol

[0330] The dumbbells are placed in steel autoclaves.

[0331] Filling water Volvic 50% by weight and ethylene glycol (Havoline) 50% by weight, sealing closed and bubbling nitrogen for at least 3.5 hours.

[0332] Pressurized with CO.sub.2 at 24 bars to obtain pH4.

[0333] Autoclaves installed in an oven at 130° C.

[0334] The dumbbells are sampled according to the plan defined.

[0335] With each sampling, the Volvic water and Havoline, inerting and pressurization are repeated.

[0336] 5 dumbbells are sampled and subjected to a traction test at a speed of 50 mm/min. The lengthening is measured by an extensometer. The mean of the resulting break on lengthening determined is reported as a function of aging time.

[0337] The results are shown in FIG. 1.

[0338] In these conditions, formulation FC1 resists for 2700 hours to have 50% of the initial lengthening.

[0339] Formulations FI1 and FI2 are still at 83 and 69% of the initial break on lengthening at 2700 hours.

[0340] For break on lengthening at the absolute break, formulation FC1 is at 77% whereas formulations FI1 and FI2 are at 156 and 165%.