Polyamide composition for material

Abstract

The present invention relates to a magnetic composite material characterized in that it comprises:

4% to 30% by weight of a copolymer,

70% to 96% by weight of magnetic powder,

0% to 5% by weight of at least one coupling agent,

0% to 5% by weight of at least one additive,

where the sum of the copolymer, the magnetic powder, the coupling agent and the additive is 100% by weight, said copolymer consisting of:

at least one unit (A) chosen from a polyamide unit,

at least one monocarboxylic acid unit (B),

at least one diamine unit (C),

at least one triamine unit (D),

optionally at least one polyetheramide unit (E),
where the sum of the constituents A, B, C, D and E is 100% by weight relative to the total weight of the copolymer.

Claims

1. A magnetic composite material comprising: 4% to 30% by weight of a copolymer, 70% to 96% by weight of magnetic powder, 0% to 5% by weight of at least one coupling agent, 0% to 5% by weight of at least one additive, where the sum of the copolymer, the magnetic powder, the coupling agent, and the additive is 100% by weight, said copolymer consisting of: at least one unit (A) chosen from a polyamide unit having an average number of carbon atoms relative to the nitrogen atom of greater than or equal to 6, at least one monocarboxylic acid unit (B), at least one diamine unit (C), at least one triamine unit (D), optionally at least one polyetheramide unit (E), where the sum of the constituents A, B, C, D, and E is 100% by weight relative to the total weight of the copolymer.

2. The magnetic composite material as claimed in claim 1, wherein the copolyamide has an acid chain end content of less than 10 ?eq/g.

3. The magnetic composite material as claimed in claim 1, wherein the copolyamide has an amine chain end content of less than 80 ?eq/g.

4. The magnetic composite material as claimed in claim 1, charactcrizcd in thatwherein the polyamide unit is from the polycondensation of at least one lactam, or of at least one aminocarboxylic acid, or of at least one diamine with at least one dicarboxylic acid.

5. The magnetic composite material as claimed in claim 4, wherein the polyamide unit is from the polycondensation of at least one lactam, or of at least one aminocarboxylic acid, or of at least one aliphatic diamine with at least one aliphatic dicarboxylic acid.

6. The magnetic composite material as claimed in claim 1, wherein the polyamide is a semicrystalline aliphatic polyamide.

7. The magnetic composite material as claimed in claim 6, wherein the semicrystalline aliphatic polyamide is chosen from PA6, PA66, PA11 and PA12 or a mixture thereof or a copolyamide thereof.

8. The magnetic composite material as claimed in claim 6, characterized in that the polyamide is chosen from PA11 and PA12.

9. The magnetic composite material as claimed in claim 1, wherein the polyamide is an amorphous polyamide.

10. The magnetic composite material as claimed in claim 1, wherein the polyetheramide unit is from the polycondensation of at least one polyetherdiamine with at least one aliphatic dicarboxylic acid.

11. The magnetic composite material as claimed in claim 1, wherein said monoacid is chosen from aliphatic monocarboxylic acids such as tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid and isobutyric acid.

12. The magnetic composite material as claimed in claim 1, wherein said monoacid is chosen from monounsaturated fatty acids.

13. The magnetic composite material as claimed in claim 12, wherein the monounsaturated fatty acid is undecylenic acid.

14. The magnetic composite material as claimed in claim 1.

15. The magnetic composite material as claimed in claim 1, wherein said triamine is chosen from diethylenetriamine (DETA), bis(hexamethylene)triamine or a polyethertriamine.

16. The magnetic composite material as claimed in claim 1, wherein the magnetic powder is chosen from iron-nickel-aluminum alloys, ferrites, samarium-cobalt alloys, neodymium-iron-boron alloys, manganese-aluminum-carbon alloys and samarium-iron-nitrogen alloys.

17. A process for producing a magnetic composite material as claimed in claim 1, characterized in that itwherein the method comprises a step of mixing the copolymer, in pellet form, with a magnetic powder, and optionally at least one coupling agent and at least one additive.

18. The process for producing a magnetic composite material as claimed in claim 17, wherein the process comprises a step of extruding and pelletizing the mixture of magnetic powder with said copolymer in pellet form and optionally the coupling agent and/or the additive.

19. The magnetic composite material as claimed in claim 1, wherein the polyamide is chosen from 11/B10, 12/B10, 11/P10, 12/P10, 11/BI/BT, 12/BI/BT, 11/PI/BT, 12/PI/BT, 11/PI/PT, 12/PI/PT, 11/BI, 12/BI, 11/PI and 12/PI.

Description

EXAMPLES

Example 1: Preparation of the Copolymers of the Invention and of Comparative Copolymers

Invention Example I1

[0217] An autoclave equipped with a stirrer is charged with 5000 g of 11-aminoundecanoic acid, 11.5 g of diethylenetriamine (DETA), 66 g of hexamethylenediamine (HMDA), 209 g of undecylenic acid, 5 g of Irganox? 1098, 6 g of 85% orthophosphoric acid, 0.2 g of siliconol 1000, and 150 g of water. The reactor is heated to 250? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 1 hour, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 50 mbar is established for 90 min, after which the reactor is emptied.

Invention Example I2

[0218] An autoclave equipped with a stirrer is charged with 2000 g of caprolactam, 11.5 g of diethylenetriamine (DETA), 508.96 g of hexamethylenediamine (HMDA), 557.04 g of adipic acid, 2000 g of lauryllactam, 209 g of undecylenic acid, 5 g of Irganox? 1098, 6 g of 85% orthophosphoric acid, 0.2 g of siliconol 1000, and 200 g of water. The reactor is heated to 260? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 4 hours, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 50 mbar is established for 90 min, after which the reactor is emptied.

Counter-Example C1

[0219] An autoclave equipped with a stirrer is charged with 5000 g of 11-aminoundecanoic acid, 70 g of lauric acid, 0.2 g of siliconol 1000, and 150 g of water. The reactor is heated to 250? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 1 hour, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 50 mbar is established for 90 min, after which the reactor is emptied.

Counter-Example C2

[0220] An autoclave equipped with a stirrer is charged with 1000 g of 11-aminoundecanoic acid, 10 1894 g of decamethylenediamine, 2160 g of sebacic acid, 90 g of stearic acid, 0.2 g of siliconol 1000, and 150 g of water. The reactor is heated to 250? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 1 hour, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 15 50 mbar is established for 90 min, after which the reactor is emptied.

Counter-Example C3

[0221] An autoclave equipped with a stirrer is charged with 1100 g of caprolactam, 398.7 g of hexamethylenediamine (HMDA), 581.3 g of adipic acid, 3000 g of lauryllactam, 5 g of Irganox? 1098, 0.2 g of siliconol 1000, and 200 g of water. The reactor is heated to 260? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 4 hours, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 50 mbar is established for 90 min, after which the reactor is emptied.

Counter-Example C4

[0222] An autoclave equipped with a stirrer is charged with 1100 g of caprolactam, 710.1 g of hexamethylenediamine (HMDA), 779.9 g of adipic acid, 2500 g of lauryllactam, 5 g of Irganox? 1098, 0.2 g of siliconol 1000, and 200 g of water. The reactor is heated to 260? C. (material temperature) under autogenous pressure and with stirring. The conditions are maintained for 4 hours, then the reactor is let down to atmospheric pressure and the temperature is lowered to 240? C. A purge phase under nitrogen is operated for 30 min before a reduced pressure of 50 mbar is established for 90 min, after which the reactor is emptied.

Example 2: Analysis of the Acidity and Basicity of the Copolymers of Example 1

[0223] The basicity and acidity are determined as described in the text and indicated in Table 1.

TABLE-US-00001 TABLE 1 COOH Amines Examples and Counter-examples (?eq/g) (?eq/g) Copolymer I1 <10 52 11-Aminoundecanoic acid + undecylenic acid + HMDA + DETA Copolymer I2 <10 60 Caprolactam + undecylenic acid + adipic acid + lauryllactam + HMDA + DETA C1 83 20 11-Aminoundecanoic acid + lauric acid Copolymer C2 48 69 11-Aminoundecanoic acid + stearic acid + sebacic acid + decamethylenediamine Copolymer C3 170 39 Caprolactam + adipic acid + lauryllactam + HMDA Copolymer C4 19 347 Caprolactam + adipic acid + lauryllactam + HMDA

Example 3: Rheological Analysis of the Magnetic Composite Materials Obtained by Mixing Comparative and Invention Copolymers with an NdFeB (5/95 weight/weight) ferrite Powder

[0224] The polymers of Examples I1, I2 and C1 to C4 are ground in liquid nitrogen and mixed with the magnetic fillers.

[0225] After drying at 90? C. under reduced pressure for 12 h, the samples are placed in a rheometer (MCR301) for measurement of the melt viscosity. A 30 min temporal sweep is performed at 1 Hz, 210? C. under nitrogen, between 2 parallel plates 25 mm in diameter.

[0226] The initial viscosity corresponds to the measurement after start-up of the rheometer: t0+10 s for recording the measurement.

[0227] The viscosity after 30 minutes corresponds to the measurement after 30 minutes of sweep in the rheometer.

[0228] Table 2 shows that the copolymers of the invention exhibit stability of viscosity, in contrast to the comparative examples.

TABLE-US-00002 TABLE 2 Initial viscosity Viscosity after 30 min Magnetic material (Pa .Math. s) (Pa .Math. s) Copolymer I1/NdFeB 1300 3850 Copolymer I2/NdFeB 1370 3920 Copolymer C1/NdFeB 6398 13 390 Copolymer C2/NdFeB 5620 12 350 Copolymer C3/NdFeB 3970 21 800 Copolymer C4/NdFeB 2710 10 000