MIXTURE OF NON-REACTIVE THERMOPLASTIC POLYMER AND REACTIVE THERMOPLASTIC POLYMER AND USE THEREOF FOR PREPARING COMPOSITES

Abstract

The use of a composition including a mixture of at least one non-reactive thermoplastic polymer of Tg >40° C., especially >100° C., in particular >120° C., and at least one reactive thermoplastic prepolymer, with a fibrous material, for the preparation of a fibrous material impregnated with the composition, the composition having an initial melt viscosity during the impregnation, as measured in plate-plate rheology under 1 Hz and 2% strain, at a temperature of 300° C., of less than the viscosity of the same composition devoid of reactive prepolymer, measured under the same conditions, and/or a ductility, after in situ polymerization of the reactive thermoplastic prepolymer in the composition during the impregnation and after the impregnation, that is at least equivalent to the ductility of the same composition devoid of non-reactive thermoplastic polymer, and of which said reactive thermoplastic prepolymer is polymerized to the same number-average molecular mass (Mn).

Claims

1. The use of a composition with a fibrous material for the preparation of a fibrous material impregnated with said composition, said composition comprising a mixture of at least one non-reactive thermoplastic polymer of Tg ≥40° C., and at least one reactive thermoplastic prepolymer, the proportion by weight of non-reactive thermoplastic polymer/reactive thermoplastic prepolymer being from 5/95 to 95/5, the non-reactive thermoplastic polymer being an amorphous polymer and the reactive thermoplastic prepolymer being a semicrystalline polymer, or the non-reactive thermoplastic polymer being a semicrystalline polymer and the reactive thermoplastic prepolymer being an amorphous polymer, said amorphous non-reactive thermoplastic polymer or said amorphous reactive thermoplastic prepolymer being chosen from: polyamides, polyetherimides (PEIs), polyaryl sulfones, and polycarbonate (PC), and said semicrystalline non-reactive thermoplastic polymer or said semicrystalline reactive thermoplastic prepolymer being chosen from: polybutylene terephthalate (PBT), polyaryletherketones (PAEKs); polyaryletherketoneketones (PAEKKs); polyamides (PAs); polyolefins, excluding atactic polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and mixtures thereof, for the preparation of a fibrous material impregnated with said composition, said composition having an initial melt viscosity during the impregnation, as measured in plate-plate rheology under 1 Hz and 2% strain, at a temperature of 300° C., of less than the viscosity of the same composition devoid of reactive prepolymer, measured under the same conditions, and/or a ductility, after in situ polymerization of said reactive thermoplastic prepolymer in said composition during the impregnation and after the impregnation, that is at least equivalent to the ductility of the same composition devoid of non-reactive thermoplastic polymer, and of which said reactive thermoplastic prepolymer is polymerized to the same number-average molecular mass (Mn).

2. The use as claimed in claim 1, wherein the proportion by weight of non-reactive thermoplastic polymer/reactive thermoplastic prepolymer is from 5/95 to 95/5.

3. The use as claimed in claim 1, wherein said semicrystalline reactive thermoplastic polymer is chosen from polybutylene terephthalate (PBT) and semiaromatic polyamides.

4. The use as claimed in claim 1, wherein said amorphous non-reactive thermoplastic polymer or said amorphous reactive thermoplastic prepolymer is chosen from: polycarbonate and polyamides (PA).

5. The use as claimed in claim 1, wherein the number-average molecular mass Mn of said non-reactive thermoplastic polymer is from 10,000 to 40,000.

6. The use as claimed in claim 1, wherein the number-average molecular mass Mn of said reactive thermoplastic prepolymer is from 500 to less than 10,000.

7. A fibrous material impregnated with a composition comprising a mixture as defined in claim 1.

8. The impregnated fibrous material as claimed in claim 7, wherein the number of fibers in said fibrous material for carbon fibers is greater than or equal to 3K, or the basis weight for the glass fiber is greater than or equal to 1200 tex.

9. The impregnated fibrous material as claimed in claim 7, wherein the content of fibers by volume is constant in at least 70% of the volume of the impregnated fibrous material.

10. The impregnated fibrous material as claimed in claim 7, wherein the degree of porosity in said impregnated fibrous material is less than 10%.

11. The impregnated fibrous material as claimed in claim 7, wherein said impregnated fibrous material is a monolayer impregnated fibrous material.

12. The impregnated fibrous material as claimed in claim 7, wherein said impregnated fibrous material is non-flexible.

13. A fibrous material pre-impregnated with a composition comprising a mixture as defined in claim 1.

14. A process for preparing an impregnated fibrous material as defined in claim 7, wherein the process comprises a step of pre-impregnating or a step of impregnating said fibrous material with the composition comprising the mixture.

15. The process as claimed in claim 14, wherein said impregnation step is carried out by the molten route.

16. The process as claimed in claim 14, wherein it comprises the following steps: i) impregnating a fibrous material with a composition comprising said mixture by the molten route to obtain an impregnated fibrous material, ii) optionally a step of shaping and calibrating said impregnated fibrous material to obtain an impregnated fibrous material consisting of a ribbon in the form of a thin strip with a thickness of from 0.05 to 5 mm.

17. The process for preparing an impregnated fibrous material or a pre-impregnated fibrous material as claimed in claim 14, wherein it comprises a step of pre-impregnating said fibrous material with a composition comprising said mixture in powder form.

18. The process as claimed in claim 17, wherein said pre-impregnation is carried out with a system chosen from a fluidized bed, gun spraying, continuous passage of the fibers through an aqueous dispersion of powder of said non-reactive thermoplastic polymer or aqueous dispersion of particles of said thermoplastic polymer or aqueous emulsion or suspension of said non-reactive thermoplastic polymer.

19. The process as claimed in claim 17, wherein it comprises at least one step of tensioning-free heating of said pre-impregnated fibrous material.

20. The process as claimed in claim 17, wherein it comprises at least one step of heating carried out by means of at least one tension device (E) and at least one heating system, said roving or said rovings being in contact with part or all of the surface of said at least one tension device (E) and running partially or completely over the surface of said at least one tension device (E) close to, at or after the heating system.

21. Process as claimed in claim 19, wherein the heating system is chosen from an infrared lamp, a UV lamp, convection heating, microwave heating, laser heating and high-frequency (HF) heating.

22. The process as claimed in claim 17, wherein it comprises the following steps: i) pre-impregnating a fibrous material with a composition comprising said mixture by fluidized bed in a tank which may or may not be equipped with a tension device (E′), by nozzle or gun spraying by the dry route in a tank which may or may not be equipped with at least one tension device (E′), to obtain a pre-impregnated fibrous material, ii) a step of tensioning-free heating of said pre-impregnated fibrous material to obtain a fibrous material pre-impregnated with said mixture of molten polymer(s) and prepolymer(s), iii) a step of heating carried out by means of at least one tension device (E) and at least one heating system to obtain an impregnated fibrous material, iv) optionally a step of shaping and calibrating the roving or said parallel rovings of said impregnated fibrous material to obtain an impregnated fibrous material consisting of a ribbon in the form of a thin strip.

23. The process as claimed in claim 17, wherein it comprises the following steps: i) pre-impregnating a fibrous material with a composition comprising said mixture by continuous passage of the fibers through a fluidized bed of dry polymer powder, an aqueous dispersion of polymer powder or aqueous dispersion of polymer particles or aqueous emulsion or suspension of polymer, ii) a step of tensioning-free heating of said pre-impregnated fibrous material to obtain a fibrous material impregnated with said mixture of molten polymer(s) and prepolymer(s), iii) optionally a step of heating carried out by means of at least one tension device (E) and at least one heating system to obtain an impregnated fibrous material, iv) optionally a step of shaping and calibrating the roving or said parallel rovings of said impregnated fibrous material to obtain a fibrous material impregnated with said mixture of polymer(s) and partially or completely polymerized prepolymer(s), consisting of a ribbon in the form of a thin strip.

24. The process as claimed in claim 14, wherein one or more tension device(s) (E″) is/are present upstream of the impregnation or pre-impregnation step.

25. The process as claimed in claim 17, wherein it is carried out for the dry powder route at a speed of between 5 and 30 m/min and for the aqueous dispersion at a speed of at least 5 m/min.

26. The use of an impregnated fibrous material, as defined in claim 7, for the preparation of ribbons suitable for the manufacture of three-dimensional composite parts, by automated layup of said ribbons using a robot.

27. The use of an impregnated fibrous material, as defined in claim 7, for the preparation of thermoformable sheets.

28. The use as claimed in claim 27, wherein the impregnated fibrous material is precut into pieces, said pieces being randomly associated or oriented for the preparation of the thermoformable sheet.

Description

EXAMPLES

Example 1: Synthesis of BACT/10T

[0174] 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:

[0175] 5 kg of the following starting materials are introduced into a 14-liter autoclave reactor:

[0176] 500 g of water,

[0177] the diamines,

[0178] the amino acid (optionally),

[0179] the terephthalic acid and optionally one or more other diacids,

[0180] 35 g of sodium hypophosphite in solution,

[0181] 0.1 g of a Wacker AK1000 antifoaming agent (Wacker Silicones).

[0182] The closed reactor is purged of its residual oxygen and then heated to a temperature of 280° 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 material temperature so that it becomes established at Tm+10° C. at atmospheric pressure.

[0183] To obtain the prepolymer, the pressure reduction has to be stopped at approximately 15 bar or have greatly limited the polymer to stop its growth.

[0184] The polymer or oligomer (prepolymer) is subsequently emptied out via the bottom valve, then cooled in a water trough and then ground.

Example 2: Impregnation of a Fibrous Material (Carbon Fiber) With a Powder of Non-Reactive Polymer or of Reactive Prepolymer or of a Mixture of the Two

[0185] The fibrous material (¼″ Toray, 12K T700S 31E carbon fiber) was pre-impregnated in a fluidized bed and then impregnated by heating as described in WO2018/234439 with a powder:

[0186] of a non-reactive polymer (Rilsan® Clear G850 Rnew® (Arkema) of Tg=150° C. and solution viscosity of 1.2 (measured in m-cresol, at 20° C., in accordance with ISO 307:2019, using a Schott type 538-23 IIC micro-Ubbelohde tube) corresponding to an Mn of 20 000 g/mol or BACT/10T (51.9/48.1 by weight) of Mn=20 000 g/mol and Tg=160° C. or Xenoy™ (PC/PBT SABIC) (1103 or HX5600HP)); or

[0187] of a reactive prepolymer BACT/10T (51.9/48.1 by weight) of Mn=6300 g/mol and Tg=160° C.; or

[0188] of a 60/40 mixture of non-reactive polymer (Rilsan® Clear G850 Rnew® (Arkema) of Tg=150° C. and solution viscosity of 1.2 (measured in m-cresol, at 20° C., in accordance with ISO 307:2019, using a Schott type 538-23 IIC micro-Ubbelohde tube) corresponding to an Mn of 20 000 g/mol and of reactive prepolymer BACT/10T (51.9/48.1 by weight) of Mn=6300 g/mol and Tg=160° C.

Example 3: Comparison of the Viscosity and Ductility of Various Compositions of Amorphous or Semicrystalline Polymer and Prepolymer and the Mixture Thereof

[0189] The viscosity is measured in plate-plate rheology under 1 Hz and 2% strain, at a temperature of 300° C., and the ductility is determined by the elongation at break at a temperature of 23° C. as measured in accordance with ISO 527-1/2:2012.

[0190] An INSTRON® 5966 type machine is used. The crosshead speed is 5 mm/min. The test conditions are 23° C., dry, with the samples of ISO 527 1A geometry having been conditioned beforehand for 2 weeks at 23° C., 50% RH. The strain is measured by a contact extensometer.

[0191] The results are shown in table 1.

TABLE-US-00001 TABLE 1 POLYMER OR VISCOSITY PREPOLYMER OR at 300° C. DUCTILE/ MIXTURE OF THE TWO (Pa .Math. s) BRITTLE C1 250  DUCTILE AMORPHOUS POLYMER Elongation at Rilsan ® Clear G850 Rnew ® break >50% (Arkema) Mn = 20 000 g/mol C2 5000  BRITTLE SEMICRYSTALLINE Elongation at POLYMER BACT/10T break 3% (51.9/48.1) Mn = 20 000 g/mol C3 70 DUCTILE SEMICRYSTALLINE Elongation at POLYMER Xenoy ™ break >=100% (SABIC) (1103 or HX5600HP) MIXTURE OF PC AND PBT I1 150 before DUCTILE after 60% by weight of polymerization polymerization AMORPHOUS POLYMER of the of the BACT/10T Rilsan ® Clear G850 Rnew ® BACT/10T Elongation at (Arkema) Mn = 20 000 g/mol + break >50% 40% by weight of SEMICRYSTALLINE PREPOLYMER BACT/10T (51.9/48.1) Mn = 6300 g/mol I2 100 before DUCTILE after 20% by weight of polymerization polymerization AMORPHOUS POLYMER of the of the BACT/10T Rilsan ® Clear G850 Rnew ® BACT/10T Elongation at (Arkema) Mn = 20 000 g/mol + break 20% 80% by weight of SEMICRYSTALLINE PREPOLYMER BACT/10T (51.9/48.1) Mn = 6300 g/mol I3 10 DUCTILE after 40% by weight of polymerization AMORPHOUS POLYMER of the PBT PC + 60% by weight of Elongation at SEMICRYSTALLINE break >10% PREPOLYMER PBT C1 to C3: comparative compositions I1 to I3: compositions according to the invention

Results

[0192] I1: the 60/40 by weight mixture of amorphous non-reactive polymer G850 and of semicrystalline reactive prepolymer BACT/10T (mass 6300 g/mol) is more fluid before in situ polymerization of the BACT/10T prepolymer than the pure G850 and the mixture is ductile after in situ polymerization just as the pure G850 was.

[0193] I2: the 20/80 by weight mixture of amorphous non-reactive polymer G850 and of semicrystalline reactive prepolymer BACT/10T (mass 6300 g/mol) is more fluid (100 Pa.Math.s) before in situ polymerization of the BACT/10T prepolymer than the pure G850 and is more ductile than the pure BACT/10T (Mn 20 000 g/mol) after in situ polymerization of the BACT/10T prepolymer up to 15 000 g/mol.

[0194] I3: the 40/60 by weight mixture of amorphous PC polymer and of PBT prepolymer (prepolymer mass 5000 g/mol) is more fluid before polymerization than the commercial PC/PBT mixture, and after polymerization of the PBT the mixture is ductile like the commercial product and has a Tm of 220° C., which is comparable to the commercial product.

Example 4: Determination of the Degree of Porosity by Image Analysis

[0195] The porosity was determined by image analysis of a 1/4″ carbon fiber roving impregnated with MPMDT/10T in fluidized bed with upstream tension devices followed by a heating step as defined above.

[0196] It is less than 5%.

Example 5: Determination of the Degree of Porosity—the Relative Deviation Between Theoretical Density and Experimental Density (General Method)

[0197] a) The data required are: [0198] The density of the thermoplastic matrix [0199] The density of the fibers [0200] The basis weight of the reinforcement: [0201] linear density (g/m) for example for a′ inch tape (derived from a single roving) surface density (g/m.sup.2) for example for a wider tape or a woven fabric

[0202] b) Measurements to be performed:

[0203] The number of samples must be at least 30 so that the result is representative of the material studied.

[0204] The measurements to be performed are: [0205] The size of the samples taken: [0206] Length (if linear density is known). [0207] Length and width (if surface density is known). [0208] The experimental density of the samples taken: [0209] Measurements of mass in air and in water. [0210] Measurement of the content of fibers is determined in accordance with ISO 1172:1999 or by thermogravimetric analysis (TGA) as determined for example in document B. Benzler, Applikationslabor, Mettler Toledo, Giesen, UserCom 1/2001.

[0211] The measurement of the content of carbon fibers may be determined according to ISO 14127:2008.

[0212] Determination of the theoretical weight content of fibers:

[0213] a) Determination of the theoretical weight content of fibers:

[00001]$\begin{array}{cc}\%{\mathrm{Mf}}_{\mathrm{th}}=\frac{m_l.L}{{\mathrm{Me}}_{\mathrm{air}}}& \left[\mathrm{Math}1\right]\end{array}$

[0214] with

[0215] m.sub.lthe linear density of the tape,

[0216] L the length of the sample and

[0217] Me.sub.air the mass of the sample measured in air.

[0218] The variation in the weight content of fibers is assumed to be directly linked to a variation in the content of matrix without taking into account the variation in the amount of fibers in the reinforcement.

[0219] b) Determination of the theoretical density:

[00002]$\begin{array}{cc}{d}_{\mathrm{th}}=\frac{1}{\frac{1-\%{\mathrm{Mf}}_{\mathrm{th}}}{d_m}+\frac{\%{\mathrm{Mf}}_{\mathrm{th}}}{d_f}}& \left[\mathrm{Math}2\right]\end{array}$

[0220] with d.sub.m and d.sub.f the respective densities of the matrix and of the fibers.

[0221] The theoretical density thus calculated is the accessible density if there is no porosity in the samples.

[0222] c) Evaluation of the porosity:

[0223] The porosity is then the relative deviation between the theoretical density and the experimental density.