Compositions of polyamide and PEBA for the injection of fatigue-resistant rigid parts

Abstract

Composition including: (A) 50% to 95% of at least one semicrystalline polyamide of formula A/Z in which: A is an aliphatic repeating unit chosen from a unit obtained from the polycondensation of at least one amino acid and a unit obtained from the polycondensation of at least one lactam or a unit X.Y obtained from the polycondensation of at least one diamine, and of at least one dicarboxylic acid, and Z represents another polyamide and is included from 0 to 20%; (B) 5% to 50% of at least one semicrystalline copolyamide comprising amide units (Ba1) and including polyether units (Ba2), having a glass transition temperature (T.sub.g) below 75 C.; (C) 0% to 20% by weight of fibres and/or fillers, (D) 0% to 20% of at least one impact modifier, (E) 0% to 5% of at least one additive, for the manufacture of a sports article.

Claims

1. A composition comprising, by weight, the total being equal to 100%: (A) 75% to 95% of at least one semicrystalline polyamide of formula A/Z in which: A is a polyamide with an aliphatic repeating unit chosen from a unit obtained from the polycondensation of at least one amino acid, a unit obtained from the polycondensation of at least one lactam, or a unit X.Y obtained from the polycondensation: of at least one diamine, said diamine being chosen from a linear or branched aliphatic diamine, a cycloaliphatic diamines, and an aromatic diamine, and of at least one dicarboxylic acid, said diacid being chosen from: an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid, said diamine and said diacid comprising from 4 to 36 carbon atoms, and Z represents a polyamide different than A and is included from 0 to 20%; (B) 5% to 25% of at least one semicrystalline copolyamide comprising amide units (Ba1) and comprising polyether units (Ba2), having a glass transition temperature (T.sub.g) below 75 C., said amide unit (Ba1) corresponding to an aliphatic repeating unit chosen from a unit obtained from at least one amino acid, a unit obtained from at least one lactam, or a unit X.Y obtained from the polycondensation: of at least one diamine, said diamine being chosen from a linear or branched aliphatic diamine and an aromatic diamine, and of at least one dicarboxylic acid, said diacid being chosen from: an aliphatic diacid and an aromatic diacid, said diamine and said diacid comprising from 4 to 36 carbon atoms; said polyether units (Ba2) resulting from at least one polyalkylene ether polyol, the blend (A) +(B) having a flexural modulus included from 600 to less than 1000 MPa, as determined according to standard ISO 178:2010; (C) 0% to 20% by weight of fibres and/or fillers, (D) 0% to 20% of at least one impact modifier, (E) 0% to 5% of at least one additive chosen from stabilisers, dyes, with the exception of a photochromic dye, and plasticisers, for the manufacture of a sports article.

2. The composition according to claim 1, wherein said composition is substantially devoid of transparency.

3. The composition according to claim 1, wherein the copolyamide (B) has a crystallinity such that the enthalpy of fusion during the second heating in an ISO DSC (delta Hm(2)) is at least equal to 25 J/g, the weight of copolyamide (B) being relative to the amount of amide units contained or of polyamide contained, this melting corresponding to that of the amide units.

4. The composition according to claim 1, wherein the amide units (Ba1) represent at least 50% by weight of the copolyamide (B).

5. The composition according to claim 1, wherein the polyether units (Ba2) represent at least 15% by weight of the copolyamide (B).

6. The composition according to claim 1, wherein the polyether units (Ba2) are chosen from polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene glycol (PO3G), polytetramethylene glycol (PTMG) and mixtures thereof or copolymers thereof.

7. The composition according to claim 1, comprising: (A) 75% to 95%, (B) 5% to 25%, and (E) 0% to 5%, wherein the sum A +B +E being equal to 100%.

8. The composition according to claim 7, wherein the sports article is a ski boot or a part of a ski boot.

9. The composition according to claim 1, comprising: (A) 75% to 95%, (B) 5% to 25%, (D) 0.1% to 10%, and (E) 0% to 5%, wherein the sum A +B +D +E being equal to 100%.

10. The composition according to claim 1, comprising: (A) 75% to 95%, (B) 5% to 25%, (C) 2% to 10%, and (E) 0% to 5%, wherein the sum A +B +C +E being equal to 100%.

11. The composition according to claim 10, comprising fibres (C).

12. The composition according to claim 10, wherein the sports article is a rigid boot with studs.

13. The composition according to claim 10, comprising fillers (C).

14. The composition according to claim 13, wherein the polyamide (A) is chosen from PA-4.6; PA-6.6; PA-6.9; PA-6.10; PA-6.12; PA-10.12; PA-10.10 and PA-12.12, and/or the amide Ba1 is chosen from PA11 and PA12.

15. The composition according to claim 10, wherein the composition has a flexural modulus included from 1400 to 2100 MPa, as determined according to standard ISO 178:2010.

16. The composition according to claim 1, wherein the polyamide (A) and/or the amide (Ba1) is chosen from PA11 and PA12.

17. The composition according to claim 16, wherein the polyamide (A) and/or the amide (Ba1) is (are) biobased.

18. A method of manufacturing a sports article, the method comprising utilizing a composition as defined in claim 1, for the manufacture of a sports article.

19. A process for preparing a composition as defined in claim 1, comprising a step of mixing the constituents (A), (B) and, where appropriate, (C) to (E) in the molten state, at a temperature of from 230 to 330 C., and the recovery thereof in the form of granules, which granules will subsequently be injected, at a temperature of from 230 to 330 C., onto an injection-moulding machine.

20. A process for preparing a composition as defined in claim 1, comprising a step of mixing the constituents (A), (B) and, where appropriate, the constituents (C) to (E), which are in the form of granules, this mixture then being injected, at a temperature of from 230 to 330 C., onto an injection-moulding machine.

21. A fashioned article comprising the composition as defined in claim 1, wherein the fashioned article comprises a fibre, fabric, film, sheet, rod, tube or injection-moulded part.

22. The fashioned according to claim 21, wherein the fashioned article consists of a sports article.

Description

EXAMPLES

Example 1

PA/PEBA Blends

(1) Composition of the Invention:

(2) (A) PA11: 84.7% (biobased) (B) PA11/PTMG 1000 (50/50): 15% (biobased) Additives: antioxidants Irganox 245 and Irgafos126.

(3) Table 1 presents the values obtained regarding 6 principal criteria required for the manufacture of a sports article.

(4) TABLE-US-00001 TABLE 1 type name or composition Invention1 Comp C1 Comp C2 Comp C3 Comp C4 PA11 84.7 Pebax 95.2% PA12(5000) + 100 4.8% PTMG (250) Pebax 95.7% PA11 (5600) + 100 4.3% PTMG (250) PA12 Pebax 50% PA11 (1000) + 15 50% PTMG (1000) stabiliser Irgafos 126 0.2 stabiliser Irganox 245 0.1 flexural modulus ISO 178: 2010 850 513 560 710 710 Ross Flex 150 000 cycles no no no no no breakage breakage breakage breakage breakage multiaxial impact ISO 6603-2 ductile ductile ductile ductile ductile 23 C . notched Charpy impact ISO 179-1: 2010 16 10 16 75 40 (30 C.) flow length (900 b, 260 C., 2 mm) 420 mm 175 mm aesthetics/ good good good medium medium coloration % renewable material >90% 0% >90% 0% 0% The various PEBAX products are sold by the company Arkema. The number between parentheses indicates the average molecular weight of the polyamide and of the polyether. Irgaphos 126 is a phosphite-based antioxidant sold by Ciba-BASF. Irganox 245 is a phenol-type antioxidant. Comp C1 = Comparative composition C1: PA12 (not biobased) Comp C2 = Comparative composition C2: PA11 (biobased) Comp C3 = Comparative composition C3: Grilamid L25ANZ (PA12 not biobased) sold by the company EMS. It corresponds to a blend of PA12 and polyolefins and is customarily used for the manufacture of ski boots. The introduction of polyolefins as impact modifier gives the composition a matt appearance and a more viscous aspect that is difficult to colour. Comp C4 = Comparative composition C4: Grilamid XE4158 (PA12 not biobased) sold by the company EMS. It has the characteristic of being more fluid than composition C3. The values in italics indicate properties that are insufficient for the manufacture of sports articles.

(5) Compositions C1 to C4 exhibit either a modulus that is too low, or a charpy impact that is too low or a flow length value that is too low for the manufacture of such articles.

(6) Only the composition of the invention exhibits good values with regard to the 6 criteria retained. The introduction of PEBA will counterbalance the disadvantages of the polyolefins by making it possible to fluidify the composition and to make it easier to colour.

(7) Moreover, the composition of the invention 1 also exhibits a ductile nature in multiaxial impact at 20 C.

Example 2

Mixtures of PA/PEBA and Additives

(8) The properties of compositions of the invention: PA 10.10 or PA11 in the presence of additives such as fibres or fillers, in comparison with comparative compositions, are presented in Table 2:

(9) TABLE-US-00002 TABLE 2 type name or composition Invention 1 Invention 2 Invention 3 comp C1 comp C2 comp C3 comp C4 comp C5 PA10.10 84.3 84.3 93.7 92 93.7 91.7 PA11 77.9 91.7 Talc Jetfine 3CA 7.4 6 8 Pebax PA11/PTMG 8 8 15 1000/1000 (50/50) Glass fibre Asahi CSX 6.8 8 3J451S wollastonite Nyglos 8 7.4 6 8 wollastonite Tremin 939 stabiliser NaHPO.sub.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 stabiliser Irganox 245 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 flexural modulus ISO 178: 2010 1747 1607 1464 1873 2073 1784 1941 1908 Ross Flex 150 000 no no no 60% 60% 60% 100% no cycles breakage breakage breakage breakage breakage breakage breakage breakage multiaxial impact ISO 6603-2 ductile ductile ductile ductile ductile ductile ductile brittle 23 C. flow length 434 488 329 366 389 490 474 398 PA 10.10 and PA11 are sold by the company Arkema. Jetfine 3CA is sold by the company Imerys. Asahi CSX 3J451S is sold by the company Asahi Kasei Incorporation. Nyglos 8 is sold by the company Nyco Minerals Incorporation. Tremin 939 is sold by the company Quartzwerke. The values in italics indicate properties that are insufficient for the manufacture of sports articles.

(10) The compositions of the invention 1 and 2 exhibit superior characteristics (in particular in terms of Ross flex and of multiaxial impact at 23 C., with additives such as fillers (talc and wollastonite respectively)) compared with the composition of the invention 3 consisting of PA11, PEBA and glass fibres, which itself exhibits superior characteristics compared with comparative composition C5 consisting of PA11 and glass fibres (without PEBA).

(11) Moreover, the composition of the invention 1 also has a ductile nature in multiaxial impact at 10 C.