POLYAMIDE COMPOSITIONS HAVING HIGH ADHESION TO METAL AND USE THEREOF

Abstract

A composition including from: a) 35% to 100% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ wherein MXD is meta-xylylenediamine and Z is a C6 to C12 aliphatic dicarboxylic acid, the semicrystalline aliphatic polyamide and/or the polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g; b) 0 to 25% by weight of polyolefins; c) 0 to 60% by weight, of glass fibers; d) 0 to 2% by weight of at least one additive; e) 0 to 30% by weight of at least one flame retardant; the sum a)+b)+c)+d)+e) being equal to 100%, the semicrystalline aliphatic polyamide and/or the polyamide of formula MXDZ having a melt flow index (MFI) between from 4 to 50 g/10 min.

Claims

1. The use of a composition comprising from: a) 35% to 100% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ wherein MXD is meta-xylylenediamine and Z is a C6 to C12 aliphatic dicarboxylic acid, said semicrystalline aliphatic polyamide and/or said polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g, a semicrystalline polyamide denoting a polyamide which has a glass transition temperature in DSC according to standard ISO 11357-2:2013 and also a melting temperature (Tm) in DSC according to standard ISO 11357-3:2013, and a enthalpy of crystallization during the cooling step at a rate of 20K/min in DSC measured according to standard ISO 11357-3 of 2013 of greater than 30 J/g, and said semicrystalline polyamide having an average number of carbon atoms relative to the nitrogen atom of greater than or equal to 6; b) 0 to 25% by weight of polyolefins; c) 0 to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; e) 0 to 30% by weight of at least one flame retardant; the sum a)+b)+c)+d)+e) being equal to 100%, said semicrystalline aliphatic polyamide and/or said polyamide of formula MXDZ having a melt flow index (MFI) between from 4 to 50 g/10 min, as measured according to standard ISO 1133:2011 under a load of 2.16 kg at 210° C., to increase the adhesion of said composition to a metal part after the deposition thereof by injection molding on said metal part, relative to the adhesion obtained after injection molding on said part with a composition comprising a semicrystalline aliphatic polyamide and/or a polyamide of formula MXDZ having at least one of the three properties, chosen from the MFI, total acidity and total basicity, which is different.

2. The use as claimed in claim 1, wherein said metal part is chosen from magnesium, aluminum, alloys thereof, alloys of stainless steel and other iron-based alloys.

3. The use as claimed in claim 1, wherein said metal part is chemically or physically pretreated before injection molding of said composition.

4. The use as claimed in claim 3, wherein said metal part is made of aluminum, said aluminum part being physically or chemically pretreated.

5. The use as claimed in claim 4, wherein said composition consists of: a) 35% to 100% by weight of said at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ; c) 0 to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; e) 0 to 30% by weight of at least one flame retardant; the sum a)+c)+d)+e) being equal to 100%.

6. The use as claimed in claim 4, wherein the adhesion of said composition to said metal part is greater than 10 MPa, as measured according to standard ISO 19095-2015.

7. The use as claimed in claim 3, wherein said metal part is made of stainless steel, said stainless steel part being physically or chemically pretreated.

8. The use as claimed in claim 7, wherein said composition consists of: a) 35% to 65% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ; b) 0 to 25% of polyolefins by weight of polyolefins; c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; e) 10% to 30% by weight of at least one flame retardant; the sum a)+b)+c)+d)+e) being equal to 100%.

9. The use as claimed in claim 7, wherein said composition consists of: a) 35% to 65% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ; b) 10% to 25% polyolefins; c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; the sum a)+b)+c)+d) being equal to 100%.

10. The use as claimed in claim 7, wherein the composition has a dielectric constant, Dk, of less than or equal to 4.0, as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, at 23° C., under 50% RH.

11. The use as claimed in claim 7, wherein the composition has a Df<0.015 at a frequency of at least 1 GHz, at 23° C., under 50% RH, measured according to ASTM D-2520-13.

12. A composition as defined in claim 1, comprising: a) 35% to 75% by weight of said at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g, b) 0 to 25% by weight of polyolefins; c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; e) 0 to 30% by weight of at least one flame retardant; the sum a)+b)+c)+d)+e) being equal to 100%, said semicrystalline aliphatic polyamide and/or said polyamide of formula MXDZ having a melt flow index (MFI) between from 4 to 50 g/10 min, as measured according to standard ISO 1133:2011 under a load of 2.16 kg at 210° C.

13. The composition as claimed in claim 12, wherein it consists of: a) 35% to 75% by weight by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g, c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; e) 0 to 30% by weight of at least one flame retardant; the sum a)+c)+d)+e) being equal to 100%.

14. The composition as claimed in claim 12, wherein it consists of: a) 35% to 75% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g; b) 0 to 25% of polyolefins; c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; the sum a)+b)+c)+d) being equal to 100%.

15. The composition as claimed in claim 12, wherein it consists of: a) 35% to 65% by weight of at least one semicrystalline aliphatic polyamide and/or one polyamide of formula MXDZ having a total acidity between from 70 to 180 μeq/g and a total basicity of less than 100 μeq/g; b) 10% to 25% polyolefins; c) 25% to 60% by weight of glass fibers; d) 0 to 2% by weight of at least one additive; the sum a)+b)+c)+d) being equal to 100%.

16. A process for preparing an article for electrical and electronic applications comprising a step of injection molding, on a metal part, of a composition as defined in claim 1, to obtain a metal part coated on one of its surfaces with said composition.

17. The process as claimed in claim 16, wherein said metal part is chosen from magnesium, aluminum, alloys thereof, alloys of stainless steel and other iron-based alloys.

18. The process as claimed in claim 17, wherein said metal part is chemically or physically pretreated before injection molding of said composition.

19. The process as claimed in claim 18, wherein said metal part is made of aluminum, said aluminum part being physically or chemically pretreated.

20. The process as claimed in claim 18, wherein said metal part is made of stainless steel, said stainless steel part being physically or chemically pretreated.

21. The process as claimed in claim 19, wherein it further comprises a subsequent step of annealing in order to obtain a coated and annealed metal part.

22. The process as claimed in claim 21, wherein it further comprises, after the annealing, a subsequent step of anodization in order to obtain a coated, annealed metal part comprising an electrically insulating layer after anodization.

23. The process as claimed in claim 21, wherein it further comprises, after the annealing, a subsequent step of coating a layer of metal, an alloy or a composite material on both surfaces of said coated metal part, to obtain a coated, annealed metal part having a layer of metal, an alloy or a composite material on both surfaces of said coated metal part.

24. An article comprising a metal part coated on one of its surfaces with a composition as defined in claim 1.

25. The article as claimed in claim 24, further comprising an electrically insulating layer after anodization.

26. The article as claimed in claim 25, further comprising a layer of metal, an alloy or a composite material.

27. The article as claimed in claim 26, further comprising a layer of adhesive over said layer of metal, alloy or composite material.

Description

EXAMPLES

[0819] Preparation of the compositions of the invention and mechanical properties:

[0820] The PA11 in EX1, EX3, EX4 and EX5 of table 1 below (Total basicity: 18 μeq/g, Total acidity: 103 μeq/g and MFI=47 g/10 min) is a PA11 limited by adipic acid (C6 diacid) at a content of 0.67% by weight relative to the amount of 11-aminoundecanoic acid charged.

[0821] This polyamide is prepared according to the following process. The 11-aminoundecanoic acid, water and adipic acid are charged to a reactor, then placed under an inert atmosphere. The temperature of the reaction medium is then raised to 235° C., while maintaining stirring. The reaction medium is maintained at 235° C., under a pressure of 20 bar for 1 h 30 min. Then, the pressure is reduced to 12 bar, while maintaining the temperature at 235° C. The material is then transferred to a polymerizer, under nitrogen flushing at 235° C.

[0822] The temperature is maintained under nitrogen flushing for 1 h 30 min. The material is then extruded in the form of granules.

[0823] This process is used for all the polyamides exemplified by varying the nature of the chain limiter and the concentration thereof, except for MXD10 for which meta-xylylene diamine and sebacic acid are used instead of 11-aminoundecanoic acid.

[0824] The PA11 in CE1 of table 1 below (Total basicity: 55 μeq/g, Total acidity: 17 μeq/g and MFI=5 g/10 min) is a PA11 limited by decanediamine (C10 diamine) at a content of 0.47% by weight relative to the amount of 11-aminoundecanoic acid charged.

[0825] The PA11 in CE3 of table 1 below (Total basicity: 97 μeq/g, Total acidity: 16 μeq/g and MFI=18 g/10 min) is a PA11 limited by decanediamine (C10 diamine) at a content of 0.47% by weight relative to the amount of 11-aminoundecanoic acid charged.

[0826] The PA11 in EX2 of table 1 below (Total basicity: 22 μeq/g, Total acidity: 71 μeq/g and MFI=6 g/10 min) is a PA11 limited by adipic acid (C6 diacid) at a content of 0.27% by weight relative to the amount of 11-aminoundecanoic acid charged.

[0827] The PA11 in CE2 of table 1 below has a total basicity=50 μeq/g and a total acidity=45 μeq/g and MFI=10 g/10 min.

[0828] The MXD10 in EX3 and EX5 of table 1 below has a total basicity: 24 μeq/g and a total acidity: 114 μeq/g and MFI=18 g/10 min.

[0829] The PA11 in CE4 of table 1 (MFI=2 g/10 min, having a total basicity=21 μeq/g and a total acidity: 75 μeq/g is a PA11 limited with 0.3% H.sub.3PO.sub.4.

[0830] The compositions of Table 1 were prepared by melt blending the polymer granules with the polyolefins when they are present, the glass fibers when they are present, the hollow glass beads when they are present, the flame retardants when they are present and the additives when they are present. This blending was carried out by compounding on a co-rotating twin-screw extruder with a diameter of 26 mm with a flat temperature profile (T°) at 240° C. The screw speed is 250 rpm and the throughput is 20 kg/h.

[0831] The glass fibers or hollow glass beads, when they are present, are introduced via side feeding.

[0832] The polyamide(s), the polyolefins and the additives are added during the compounding process via the main hopper.

[0833] The flame retardants, when they are present, are introduced via side feeding or via the main hopper.

TABLE-US-00001 TABLE 1 EX 1 CE1 EX 2 EX3 CE2 EX 4 CE3 EX5 CE4 PA11 59.4 41.6 39.4 24.5 MFI = 47 g/10 min Total basicity: 18 μeq/g Total acidity: 103 μeq/g PA11 59.4 MFI = 6 g/10 min Total basicity: 22 μeq/g Total acidity: 71 μeq/g PA11 59.4 MFI = 5 g/10 min Total basicity: 55 μeq/g Total acidity: 17 μeq/g PA11 64.7 MFI = 18 g/10 min Total basicity: 97 μeq/g Total acidity: 16 μeq/g PA 11 64.4 MFI = 10 g/10 min Total basicity: 50 μeq/g Total acidity: 45 μeq/g PA11 59.4 MFI = 2 g/10 min Total basicity = 21 μeq/g Total acidity: 75 μeq/g MXD10 17.8 10.2 MFI = 18 g/10 min Total basicity: 24 μeq/g Total acidity: 114 μeq/g E-glass fibers 40.0 40.0 40.0 40.0 35.0 40.0 35 30 40 Glass beads 20 Exolit OP1312 20.0 Polypropylene 15 additives 0.6 0.6 0.6 0.6 0.6 0.6 0.3 0.3 0.6 Adhesion MPa 34 19 25 32 10 26 17 31 16 (without annealing) ISO 19095:2015 (average of 5 values) Dk 23° C., DAM @ 2 GHz 3.6 3.6 3.6 3.6 3.5 3.8 3.5 3.1 3.6 Df 23° C., DAM @ 2 GHz 0.01 0.01 0.01 0.01 0.01 0.013 0.01 0.008 0.01 [0834] E-glass fibers: solid E-type glass fibers of circular cross section (Nitto Boseki CSX3J451S) [0835] Exolit OP1312: flame retardant supplied by Clariant [0836] Glass beads: Hollowlite HK60-18000 hollow glass beads [0837] Polypropylene: mixture of PP5060 from Total and Orevac CA100 from SK Chemical

[0838] The MFI is measured according to standard ISO 1133:2011 under a load of 2.16 kg at 210° C.