SEMI-CRYSTALLINE POLYAMIDE COMPOSITION WITH HIGH GLASS TRANSITION TEMPERATURE FOR COMPOSITE MATERIAL, PROCESS FOR MANUFACTURING SAME AND USES THEREOF

Abstract

The invention relates to a composition for thermoplastic composite material comprising: 30% to 60% by volume, preferentially 35% to 50% by volume, of a thermoplastic matrix comprising from 50% to 100% by weight of a semi-crystalline polyamide polymer and from 0% to 50% by weight of at least one additive and/or of at least one other polymer, 40% to 70% by volume, preferentially 50% to 65% by volume, of long reinforcing fibers (or of long fibrous reinforcement), said thermoplastic matrix impregnating said long reinforcing fibers (or said long fibrous reinforcement), said semi-crystalline polyamide polymer being a nonreactive composition of at least one polyamide polymer, said composition being that of said thermoplastic matrix defined above, and said reactive polyamide prepolymer of the composition a) and said polyamide polymer of the composition b) comprising or consisting of at least one BACT/XT copolyamide.

Claims

1. A composition suitable for a thermoplastic composite material comprising: 30% to 60% by volume of a non-reactive thermoplastic matrix comprising from 50% to 100% by weight of a semi-crystalline polyamide polymer and from 0% to 50% by weight of at least one additive and/or of at least one other polymer, 40% to 70% by volume of long reinforcing fibers, said thermoplastic matrix impregnates said long reinforcing fibers, said semi-crystalline polyamide polymer comprises at least one BACT/XT copolyamide in which: BACT is a unit comprising an amide unit present at a molar content ranging from 20% to 70%, wherein BAC is chosen from 1,3-bis(aminomethyl)cyclohexyl (1,3-BAC), 1,4-bis(aminomethyl)cyclohexyl (1,4-BAC) and a mixture thereof, and T is terephthalic acid, XT is a unit comprising an amide unit present at a molar content ranging from 30% to 80%, wherein X is a C9 to C18 linear aliphatic diamine, and wherein T is terephthalic acid, in the BACT and/or XT units, independently of one another, up to 30 mol % relative to the total amount of dicarboxylic acids, of the terephthalic acid can be replaced with other aromatic, aliphatic or cycloaliphatic dicarboxylic acids comprising 6 to 36 carbon atoms, and in the BACT and/or XT units, independently of one another, up to 30 mol % of the BAC and/or where appropriate of X, relative to the total amount of diamines, can be replaced with other diamines comprising from 4 to 36 carbon atoms, and in the copolyamide, no more than 30 mol %, relative to the total amount of monomers, can be formed by lactams or aminocarboxylic acids, and on condition that the sum of the monomers which replace the terephthalic acid, the BAC and X does not exceed a concentration of 30 mol %, relative to the total amount of monomers used in the copolyamide, and on condition that BACT and XT units are always present in said polyamide polymer.

2. The composition of claim 1, wherein said semi-crystalline polyamide polymer has a melting point Mp<290 C., as determined according to the standard ISO 11357-3 (2013).

3. The composition of claim 1, wherein said semi-crystalline polyamide polymer has a glass transition temperature Tg>120 C., determined according to the standard ISO 11357-2 (2013).

4. The composition of claim 1, wherein said semi-crystalline polyamide polymer exhibits a difference between the melting point and the crystallization temperature MpTc<40 C., determined according to the standard ISO 11357-3:2013.

5. The composition of claim 1, wherein the heat of crystallization of the semi-crystalline polyamide polymer, measured by differential scanning calorimetry (DSC) according to the standard ISO 11357-3:2013, is greater than 40 J/g.

6. The composition of claim 1, wherein the BAC is 1,3-BAC.

7. The composition of claim 1, wherein the BAC is 1,3-BAC, and XT is chosen from 9T, 10T, 11T and 12T.

8. The composition of claim 1, wherein the XT is 10T, wherein 10 corresponds to 1,10-decanediamine.

9. The composition of claim 1, wherein the sum of the monomers which replace the terephthalic acid, the BAC and X is equal to 0.

10. The composition of claim 1, wherein the long reinforcing fibers have a circular cross-section with L/D>1000.

11. A process for manufacturing a thermoplastic composite material, comprising the following steps: i) melt impregnating long fibrous reinforcement with the composition of claim 1, but not comprising said long fibrous reinforcement, in an open mold, closed mold, or without a mold, to obtain a composite composition, ii) processing or molding said composite composition of stage, to form a final composite part in a mold or with another processing system.

12. The process of claim 11, wherein said processing is carried out according to an RTM, C-RTM, S-RIM, injection-compression molding or pultrusion process, or by infusion molding.

13. A mechanical or structural part comprising the thermoplastic composite material of claim 1.

14. The mechanical or structural part of claim 13, wherein said part is an part in an application selected from the group consisting of a motor vehicle, a railway, a marine craft, a wind power generator, a photovoltaic collector, a solar energy application, a solar panel, a solar power station, sports equipment, an aeronautical or aerospace application, a transportation application, building and construction, a civil engineering structure, a panel, and a leisure application.

15. The mechanical or structural part of claim 14, wherein said motor vehicle part I post-treated by cataphoresis.

16. The mechanical or structural part of claim 14, wherein said part is an element in a wind power application.

17. The mechanical or structural part of claim 14, wherein said part I an element in an aeronautical structure.

Description

DESCRIPTION OF THE FIGURES

[0239] FIG. 1 shows the Mp, Tg, Tc and Deltac He curves obtained as a function of the molar percentage of BACT in a BACT/10T copolyamide.

[0240] The curves represent:
Solid circles: Mp.
Empty circles: Tc.

Squares: Tg

[0241] Diamonds: Heat of crystallization.

Examples

[0242] APreparation of a Polyamide Polymer by the Direct Route (without Chain Extension)

[0243] The following procedure is an example of a preparation process, and is not limiting. It is representative of all the compositions according to the invention:

[0244] 5 kg of the following starting materials are introduced into a 14-liter autoclave reactor: [0245] 500 g of water, [0246] the diamines, [0247] the amino acid (optionally), [0248] the terephthalic acid and optionally one or more other diacid(s), [0249] the monofunctional chain regulator: benzoic acid, in an amount suitable for the targeted Mn and varying (benzoic acid) from 50 to 100 g, [0250] 35 g of sodium hypophosphite in solution, [0251] 0.1 g of a Wacker AK1000 antifoaming agent (Wacker Silicones).

[0252] The natures and molar ratios of the molecular structures and units of the polyamides (by referenced test) are given in table III below.

[0253] The closed reactor is purged of its residual oxygen and then heated to a temperature of 230 C. with respect to the material introduced. After stirring for 30 minutes under these conditions, the pressurized vapor which has formed in the reactor is gradually reduced in pressure over 60 minutes, while gradually increasing the internal temperature so that it becomes established at Mp+10 C. at atmospheric pressure.

[0254] The polymerization is then continued under nitrogen flushing of 20 l/h until the viscosity shown in the characteristics table is obtained.

[0255] The polymer is subsequently emptied out via the bottom valve, then cooled in a water trough and then granulated. [0256] The results are given in the following tables III-VI. They were obtained using 1,3-BAC having a cis/trans ratio of 75/25 mol %.

TABLE-US-00003 TABLE III Inherent 10T BACT Mp Tc Mp Tc DeltaHc Tg viscosity E 180 C. Ref mol % mol % C. C. C. J/g C. MPa C 10T* 100.0 0.0 314 279 35 63 120 insoluble I1 60.0 40.0 275.6 241.7 33.9 60.8 134.0 0.92 I2 50.0 50.0 281.7 248.3 33.4 53.5 153.4 1.05 805.3 I3 50.0 50.0 279.4 242.5 36.9 55.5 146.0 0.93 I4 45.0 55.0 279.8 252.0 27.8 62.2 142.7 0.87 I5 45.0 55.0 282.0 253.5 28.5 49.7 160.2 1.09 I6 40.0 60.0 286.1 250.4 35.7 57.0 163.9 0.94 886 I7 30.0 70.0 289.7 258.6 31.1 40.6 165.6 0.86 C BACT* 0.0 100.0 349 187 C denotes Comparative I denotes Invention *According to JP2015017177
The results of table 3 show that, for a BACT molar fraction of 20 (not indicated in the table) to 70 mol % (preferably 25 to 60 mol %), the melting point is below 290 C. (preferably below 280 C.). At the same time, the Tg is very high and can be modulated from 125 C. (not indicated in the table) to approximately 165 C. The heat of crystallization for all these products is particularly high, and in particular greater than 50 J/g (in particular greater than the MXDT/10T described in WO 2014/064375).

TABLE-US-00004 TABLE IV Inherent 10T BACT 11 Mp Tc Mp Tc DeltaHc Tg viscosity Ref mol % mol % mol % C. C. C. J/g C. I8 41.5 50.8 7.7 269.2 232.4 36.8 41.4 149.5 1.14 I9 38.2 46.9 14.9 256.1 189.7 66.4 28.7 144.9 1.22
The partial replacement of one of the two units with 11-aminoundecanoic acid is also possible and gives good results for obtaining a good Mp/Tg compromise (table IV).

TABLE-US-00005 TABLE V Inherent 10T BACT 6T Mp Tc Mp Tc DeltaHc Tg viscosity Ref mol % mol % mol % C. C. C. J/g C. I10 42.5 51.9 5.5 270.9 234.0 36.9 49.7 161.3 1.02 I11 40.5 49.5 10 263.9 233.2 30.7 44.5 143.2 0.86
The partial replacement of one of the two units with the 6T unit is also possible and gives good results for obtaining a good Mp/Tg compromise (table V).

TABLE-US-00006 TABLE VI Molecular structure/ Mp Tc Mp Tc DeltaHc g Inherent Ref. Test type Molar composition C. C. C. J/g C. viscosity C1 Comparative 10T/6T (59/41) 281 236 45 44 122 1.12 (EP1988113) C2 Comparative 10T/6T/11 (60/24/16) 269 220 49 39 111 1.25 (EP1988113) C3 Comparative 10T/TMDT (59/41) 263 197 66 35 133 1.15 (WO2011/00393) C10T Comparative 10T (100) 314 279 35 63 120 insoluble C4 Comparative 10T/11 (67/33) 269 232 37 50 84 1.19 C5 Comparative 10,T/11 (59/41) 261 213 46 39 78 1.15 C6 Comparative 10T/10I (67/33) 269 205 64 32 110 1.12 C7 Comparative MXDT/11 (59/41) 211 (*) >100 12 111 1.25 C8 Comparative MPMDT/11 (59/41) (*) 84 1.14 C9 Comparative 10T/MXDT (50/50) 262 211 51 17 137 0.99 (WO2014/064375) C10 Comparative 10T/MPMDT (59/41) 264 219 45 40 126 1.11 (WO2014/064375) C11 Comparative 10T/MPMDT (50/50) 245 185 60 22 127 1.12 C12 Comparative 10T/12T/11 (60/24/16) 271 246 25 56 105 0.98 (WO2014/064375) C13 Comparative 18T/MXDT (71/29) 264 242 22 47 95 0.86 (WO2014/064375) (*): No crystallization on cooling.

BPreparation of a Polyamide Polymer by Chain Extension of a Reactive Prepolymer (or Oligomer)

B-1 Preparation of Reactive Prevolymers of P(X)n (or P(Y)n) Type

[0257] The following procedure is an example of a preparation process, and is not limiting. It is representative of all the compositions according to the invention:

[0258] 5 kg of the following starting materials are introduced into a 14-liter autoclave reactor: [0259] 500 g of water, [0260] the diamines, [0261] the amino acid (optionally), [0262] the terephthalic acid and optionally one or more other diacid(s), [0263] 35 g of sodium hypophosphite in solution, [0264] 0.1 g of a Wacker AK 1000 antifoaming agent (Wacker Silicones).
The closed reactor is purged of its residual oxygen and then heated to a temperature of 230 C. of the material. After stirring for 30 minutes under these conditions, the pressurized vapor which has formed in the reactor is gradually reduced in pressure over 60 minutes, while gradually increasing the internal temperature so that it becomes established at Mp+10 C. at atmospheric pressure. The oligomer (prepolymer) is subsequently emptied out via the bottom valve, then cooled in a water trough and then ground.

[0265] The natures and molar ratios of the molecular structures and units of the polyamides (by referenced test) are given in table VII below. They were obtained using 1,3-BAC having a cis/trans ratio of 75/25 mol %.

TABLE-US-00007 TABLE VII Molecular structure Inherent Acid Amine and chemical Mp Tc Mp Tc DeltaHc Tg viscosity number number Mn** Ref. composition (mol %) C. C. C. J/g C. meq/kg* meq/kg* g/mol P1 1,3-BACT/10T (40/60) 259.2 217 45.0 121.0 0.35 713 56 2601 P2 1,3-BACT/10T (40/60) 265.7 230.6 58.6 104.6 0.42 0 639 3129 *Milliequivalents per kilogram **Potentiometric Mn

B-2 Preparation of the Polyamide Polymer by Reaction Between Prepolymer P(X)n and P(Y)n

[0266] A stoichiometric mixture (mol(acid)=(mol(amine)) of the two oligomers P1 (XCOOH) and P2 (YNH.sub.2) above, dried and ground, is introduced with nitrogen flushing into a DSM co-rotating conical screw microextruder (15 ml in volume) preheated to 280 C. with screw rotation at 100 rpm. The mixture is left to recirculate in the microextruder and the increase in the viscosity is monitored by measuring the normal force. After approximately 15 minutes, the contents of the microextruder are emptied out in the form of a rod. The air-cooled product is granulated.

[0267] The product 112 obtained has an inherent viscosity equal to 1.92.

B-3 Preparation of the Polyamide Polymer by Reaction Between Prepolymer P(X)n and an Extender Y-A-Y

[0268] 10 g of the dried and ground oligomer P1 above are mixed with a stoichiometric amount of 1,3-phenylenebisoxazoline (PBO). The mixture is introduced under nitrogen flushing into a DSM corotating conical-screw microextruder (15 ml in volume) preheated to 280 C. with rotation of the screws at 100 rev/min. The mixture is left to recirculate in the microextruder and the increase in the viscosity is monitored by measuring the normal force. After approximately 2 minutes, a plateau is reached and the contents of the microextruder are emptied out in the form of a rod. The air-cooled product is granulated.

[0269] The product 113 obtained has an inherent viscosity equal to 0.97.