MOLDING COMPOSITIONS BASED ON POLYAMIDE, ON CARBON FIBERS AND ON HOLLOW GLASS BEADS AND USE THEREOF

Abstract

Molding composition, including by weight: (A) from 38 to 79.5% of at least one semi-crystalline aliphatic polyamide with the exclusion of PA6 and PA66, (B) from 10 to 20% of carbon fibres, (C) from 10 to 20% of hollow glass beads, (D) from 5.5 to 10% of at least one impact modifier having a flexural modulus of less than 200 MPa, in particular less than 100 MPa, as measured according to standard ISO 178: 2010, at 23° C., and (E) from 0.1 to 1% by weight of at least one additive, the sum of the proportions of each constituent (A)+(B)+(C)+(D)+(E) of the composition being equal to 100%.

Claims

1. A molding composition, comprising by weight: (A) from 38 to 79.5% of at least one semi-crystalline aliphatic polyamide, (B) from 10 to 20% of carbon fibers, (C) from 10 to 20% of hollow glass beads, (D) from 5.5% to 20% of at least one impact modifier having a flexural modulus of less than 200 MPa, as measured according to standard ISO 178:2010 at 23° C., and (E) from 0.1 to 1% by weight of at least one additive selected from the fillers selected from silica, graphite, expanded graphite, carbon black, kaolin, magnesia, slag, talc, wollastonite, nanofillers (carbon nanotubes), pigments, metal oxides (titanium oxide), metals, dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes and mixtures thereof, the sum of the proportions of each constituent (A)+(B)+(C)+(D)+(E) of said composition being equal to 100%, excluding PA6 and PA66.

2. The composition according to claim 1, wherein said impact modifier is selected from a polyether block amide (PEBA), a functionalized or non-functionalized polyolefin and mixtures thereof.

3. The composition according to claim 1, wherein the impact modifier is selected from a polyether block amide (PEBA) having a flexural modulus less than 100 MPa as measured according to standard ISO 178:2010 at 23° C., and a mixture of polyether block amide (PEBA) having a flexural modulus less than 100 MPa as measured according to standard ISO 178:2010 at 23° C. with a functionalized or non-functionalized polyolefin.

4. The composition according to claim 3, wherein the PEBA has a density greater than or equal to 1, as determined according to ISO 1183-3: 1999.

5. The composition according to claim 1, wherein the impact modifier is selected from a functionalized polyolefin, a non-functionalized polyolefin and mixtures thereof, said impact modifier being present from 7 to 20.0% relative to the total weight of the composition.

6. The composition according to claim 3, wherein the functionalized polyolefin has a function selected from the maleic anhydride, carboxylic acid, carboxylic anhydride and epoxide functions.

7. The composition according to claim 1, wherein the carbon fibers are short carbon fibers having a fiber length comprised from 100 to 600 μm, said length being measured after compounding in the composition to be molded.

8. The composition according to claim 1, wherein the hollow glass beads have a mean volume diameter d.sub.50 from 10 to 80 μm, as measured by laser diffraction according to ASTM B 822-17.

9. The composition according to claim 1, wherein the hollow glass beads have a real density of 0.10 to 0.65 g/cm.sup.3, measured according to ASTM D 2840-69 (1976) with a gas pycnometer and helium as the measuring gas.

10. The composition according to claim 1, wherein the hollow glass beads have a compression resistance, as measured according to ASTM D 3102-72 (1982) in glycerol of at least 50 MPa.

11. The composition according to claim 1, wherein the semi-crystalline polyamide is obtained by polycondensation: of at least one C.sub.6 to C.sub.18 amino acid, or of at least one C.sub.6 to C.sub.18 lactam, or of at least one C.sub.4-C.sub.36 aliphatic diamine Ca with at least one C.sub.4-C.sub.36 aliphatic dicarboxylic acid Cb, or a mixture thereof.

12. The composition according to claim 1, wherein the semi-crystalline polyamide is obtained by polycondensation: of at least one C.sub.6 to C.sub.18 amino acid, or of at least one C.sub.6 to C.sub.18 lactam.

13. The composition according to claim 1, wherein said semi-crystalline polyamide is selected from is selected from PA610, PA612, PA1010, PA1012, PA1212, PA11 and PA 12.

14. The composition according to claim 1, wherein said semi-crystalline polyamide is selected from PA11 and PA12.

15. (canceled)

16. A use of a composition as defined in claim 1, for the manufacture of an article for electronics, sports, motor vehicles or industry.

17. The use according to claim 16, wherein the article is manufactured by injection molding.

18. An article obtained by injection molding with a composition as defined in claim 1.

19. A molding composition, comprising by weight: (A) from 38 to 79.5% of at least one semi-crystalline aliphatic polyamide, (B) from 10 to 20% of carbon fibers, (C) from 10 to 20% of hollow glass beads, (D) from 5.5% to 20% of at least one impact modifier having a flexural modulus of less than 200 MPa, as measured according to standard ISO 178:2010 at 23° C., and (E) from 0.1 to 1% by weight of at least one additive selected from the fillers selected from silica, graphite, expanded graphite, carbon black, kaolin, magnesia, slag, talc, wollastonite, nanofillers (carbon nanotubes), pigments, metal oxides (titanium oxide), metals, dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes and mixtures thereof, the sum of the proportions of each constituent (A)+(B)+(C)+(D)+(E) of said composition being equal to 100%, excluding PA6 and PA66, and wherein the impact modifier is selected from a polyether block amide (PEBA) having a flexural modulus less than 100 MPa as measured according to standard ISO 178:2010 at 23° C., and a mixture of polyether block amide (PEBA) having a flexural modulus less than 100 MPa as measured according to standard ISO 178:2010 at 23° C. with a functionalized or non-functionalized polyolefin.

20. A molding composition, comprising by weight: (A) from 38 to 79.5% of at least one semi-crystalline aliphatic polyamide, (B) from 10 to 20% of carbon fibers, (C) from 10 to 20% of hollow glass beads, (D) from 5.5% to 20% of at least one impact modifier having a flexural modulus of less than 200 MPa, as measured according to standard ISO 178:2010 at 23° C., and (E) from 0.1 to 1% by weight of at least one additive selected from the fillers selected from silica, graphite, expanded graphite, carbon black, kaolin, magnesia, slag, talc, wollastonite, nanofillers (carbon nanotubes), pigments, metal oxides (titanium oxide), metals, dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes and mixtures thereof, the sum of the proportions of each constituent (A)+(B)+(C)+(D)+(E) of said composition being equal to 100%, excluding PA6 and PA66, and excluding nano alumina.

Description

EXAMPLES

[0164] Preparation of the Compositions of the Invention and Mechanical Properties:

[0165] The compositions of tables I and II were prepared by melt blending polymer granules with the carbon fibers, the hollow glass beads and the additives. This mixture was made by compounding on a 26-mm diameter twin-screw co-rotating extruder with a flat temperature profile)(T° at 240° C. The screw speed is 200 rpm and the flow rate is 16 kg/h.

[0166] The introduction of carbon fibers and hollow glass beads is carried out with a side feeder.

[0167] The polyamide(s) and the additives are added during the compounding process in the main hopper.

[0168] The compositions were then molded on an injection molding machine at a material temperature of 260° C. and a molding temperature of 60° C. in the shape of dumbbells or bars in order to study the mechanical properties according to the standards below

TABLE-US-00001 TABLE I Batch no. CE 1 CE 2 CE 3 CE 4 CE 5 CE 6 PA11 74.5 70 70 70 70 70 iM16k hollow glass 10.00 10.00 10.00 10.00 10.00 10.00 beads PEBA11/PTMG 50% 4.5 PTMG, d = 1.03 PEBA 11/PTMG 4% 4.5 PTMG, d = 1.03 Engage ™ 8200 4.5 Exxelor ™ VA1803 4.5 Kraton ™ FG 1901 4.5 Teijin ™ Toho Tenax 15.00 15.00 15.00 15.00 15.00 15.00 HT C493 carbon fiber additives 0.5 0.5 0.5 0.5 0.5 0.5 density (g/cm3) 1.007 1.004 1.004 1.005 1.005 1.005 Tensile modulus 11.4 10.8 11 10.8 10.7 10.7 (GPa) ISO 527-1: 2012 Tensile strength MPa 127.2 117.6 120.2 115.3 114.2 115.2 Elongation at break % 2.9 2.9 2.8 2.7 3 3.1 Notched impact 8.7 8.9 8.8 7.2 9.1 9.0 according to ISO179: 1eA at 23° C., strength (kJ/m.sup.2) Non-notched impact at 45.8 46 45.9 43.2 46.2 45.9 23° C., strength (kJ/m.sup.2) Notched impact 6.4 6.5 6.4 7.1 6.7 6.6 according to ISO179: 1eA at −30° C., strength (kJ/m.sup.2) Non-notched impact 47.1 47.3 47 45.2 47.4 47.3 at −30° C., strength (kJ/m.sup.2) CE: Counter-example

[0169] The proportions are given in mass proportion (%)

Engage™ 8200, non-functionalized ethylene-octene copolymer, d=0.87 g/cm3, supplied by the company Dow Inc
iM16k hollow glass beads, with a real density=0.46 g/cm3, average diameter=20 μm having a compression strength >100 MPa, supplied by the company 3M Kraton™ FG 1901: linear triblock copolymer based on styrene and ethylene/butylene, functionalized with maleic anhydride, d=0.91 g/cm3, supplied by the company Kraton Polymers
Exxelor™ VA1803, functionalized ethylene copolymer with maleic anhydride, d=0.86 g/cm3, supplied by the company Exxon Mobil
Toho Tenax HT C493: carbon fiber supplied by the company Teijin
PA11: synthesized by the applicant
PEBA PA11/PTMG: synthesized by the applicant

[0170] The tensile modulus, elongation at break and tensile strength were measured at 23° C. according to standard ISO 527-1: 2012 on dry samples.

[0171] The machine used is of the INSTRON 5966 type. The speed of the crosshead is 1 mm/min for the modulus measurement and 5 mm/min for the tensile strength and elongation at break. The test conditions are 23° C.+/−2° C., on dry samples.

[0172] The impact strength was determined according to ISO 179-1: 2010 (Charpy impact) on samples of dimension 80 mm×10 mm×4 mm, notched and non-notched, at a temperature of 23° C.+/−2° C. at a relative humidity of 50%+/−10% or at −30° C.+/−2° C. at a relative humidity of 50%+/−10% on dry samples.

[0173] The density of the compositions injected was measured according to standard ISO 1183-3:1999.

TABLE-US-00002 TABLE II Batch no. EX 1 EX 2 EX 3 EX 4 EX 5 EX 6 EX 7 EX 8 EX 9 EX 10 PA11 69 67 64.5 59.5 67 69 67 64.5 59.5 67 iM16k hollow 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 glass beads PEBA 11/PTMG 5.5 7.5 10.0 15.0 3.75 50% PTMG, d = 1.03 Exxelor ™ 5.5 7.5 10.0 15.0 3.75 VA1803 VA1803 Kraton ™ 7.5 FG 1901 Teijin ™ Toho 15.0 15.0 15.00 15.0 15.0 15.0 15.0 15.0 15.0 15.0 Tenax HT C493 carbon fiber additives 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 density 1.004 1.005 1.006 1.007 1.001 1.004 1.001 0.998 0.988 1.002 (g/cm3) Tensile 10.7 10.5 10.4 9.9 10 10.5 10.1 9.6 8.6 10.3 modulus (GPa) ISO 527- 1: 2012 Tensile 116.3 114.5 113.4 109.9 104.1 109.3 103.7 98.4 87.5 109.2 strength MPa Elongation at 3 3.2 3.3 3.6 4.0 3.6 4.1 4.4 5.5 3.8 break % Notched 10.1 10.9 11.6 13.2 16 14.3 16.5 18.7 21.9 15.3 impact 1eA at 23° C., strength (kJ/m.sup.2) Non-notched 48.5 51 52.2 52.6 49.9 47.7 50.2 53.6 56.6 51.8 impact at 23° C., strength (kJ/m.sup.2) Notched 7.2 7.3 7.3 8.8 11.1 9.4 11.2 12.4 15.5 9.8 impact 1eA at −30° C., strength (kJ/m.sup.2) Non-notched 50.1 50.4 50.5 53.8 50.9 48.7 51.3 54.5 56.7 51.1 impact at −30° C., strength (kJ/m.sup.2) EX: Examples according to the invention The proportions are given in mass proportion (%).

[0174] The results presented in tables I and II show that the compositions of the invention have superior mechanical properties to comparative compositions and notably Charpy impact values at −30° C. far superior to comparative compositions.

[0175] Moreover, elongation at break is superior for the compositions of the invention relative to comparative compositions.

[0176] The compositions of the invention also have excellent processability.