Flame retardant semi-aromatic polyamide composition and moulded products made therefrom

1. A flame retardant polyamide composition comprising:

(A) a semi-crystalline semi-aromatic polyamide derived from terephthalic acid monomers and derivatives thereof and at least one diamine selected from the group consisting of butanediamine, hexamethylenediamine and 2-methylpentamethylenediamine;

(B) at least one semi-crystalline aliphatic polyamide having a number average molecular weight (Mn) of 10,000 to 25,000 g/mol which is selected from the group consisting of polyamide-4,6 (PA-4,6), polyamide-4,8 (PA-4,8), polyamide-4,10 (PA-4,10) and copolymers thereof;

(C) 10 to 30 parts by weight (pbw), based on 100 pbw of components (A)+(B), of a halogen free flame retardant system comprising a metal salt of a phosphinate of formula (I) or a diphosphinate of formula (II),

wherein R 1 and R 2 may be identical or different and are linear or branched C 1 -C 6 alkyl and/or aryl;

R 3 is linear or branched C 1 -C 10 -alkylene, C 6 -C 10 -arylene, -alkylarylene or -arylalkylene;

M is at least one ion selected from the group consisting of calcium ions, magnesium ions, aluminum ions and zinc ions;

m is 2 or 3;

n is 1 or 3; and

x is 1 or 2; and

(D) 5 to 50 weight percent, based on total weight of the composition, of inorganic fillers and/or reinforcement agents, wherein

the semi-crystalline semi-aromatic polyamide (A) and the semi-crystalline aliphatic polyamide (B) are present in a weight ratio of (A):(B) which is in a range of 75:25-94:6, and wherein

the semi-crystalline semi-aromatic polyamide (A) has a melting temperature (Tm-A) within a range of 280−350° C., and wherein

the composition exhibits a V0 rating pursuant to UL94V and no blistering when subjected to JEDEC level 2 conditions.

2. The flame retardant polyamide composition according to claim 1 , wherein the weight ratio of (A):(B) is in the range of 77:23-94:6.

3. The flame retardant polyamide composition according to claim 1 , wherein the melting temperature (Tm-A) of the semi-crystalline semi-aromatic polyamide (A) is in the range of 300-340° C.

4. The flame retardant polyamide composition according to claim 1 , wherein the semi-crystalline semi-aromatic polyamide (A) has a number average molecular weight (Mn) of more than 5,000 g/mol.

5. The flame retardant polyamide composition according to claim 1 , wherein the at least one semi-crystalline aliphatic polyamide (B) has a melting temperature (Tm-B) of at least 220° C.

6. The flame retardant polyamide composition according to claim 1 , wherein the composition further comprises inorganic fillers and/or reinforcement agents (D) in a total amount of 1-250 parts by weight (pbw) relative to 100 pbw of (A)+(B).

7. The flame retardant polyamide composition according to claim 1 , consisting of:

(A) 30-76 wt % of the semi-crystalline semi-aromatic polyamide;

(B) 2-19 wt % of the at least one semi-crystalline aliphatic polyamide;

(C) 4-35 wt % of the flame retardant system;

(D) 5 up to 45 wt % of the inorganic fillers and/or fibrous reinforcement agents;

(E) 0-20 wt % of other polymers; and

(F) 0-20 wt % of other additives, wherein

the wt % are all relative to the total weight of the composition.

8. The flame retardant polyamide composition according to claim 7 , consisting of:

(A) 15-40 wt % of the semi-crystalline semi-aromatic polyamide;

(B) 1-10 wt % of the at least one semi-crystalline aliphatic polyamide;

(C) 2-20 wt % of the flame retardant system,

(D) 5-50 wt % of the inorganic fillers and/or fibrous reinforcement agents;

(E) 0-10 wt % of the other polymers; and

(F) 0-10 wt % of the other additives; wherein

the wt % are all relative to the total weight of the composition.

9. The flame retardant polyamide composition according to claim 1 , wherein component (D) comprises glass fibres.

10. The flame retardant polyamide composition according to claim 2 , wherein the weight ratio of (A):(B) is in the range of 79:21-94:6.

11. The flame retardant polyamide composition according to claim 4 , wherein semi-crystalline semi-aromatic polyamide (A) has a number average molecular weight (Mn) in a range of 7,500 to 50,000 g/mol.

12. The flame retardant polyamide composition according to claim 5 , wherein the at least one semi-crystalline aliphatic polyamide (B) has a melting temperature (Tm-B) in a range of 250−300° C.

13. The flame retardant polyamide composition according to claim 1 , wherein the at least one semi-crystalline aliphatic polyamide (B) has a number average molecular weight (Mn) in a range of 15,000 to 25,000 g/mol.

14. The flame retardant polyamide composition according to claim 1 , wherein the flame retardant system comprises at least one metal salt of a (di)phosphinic acid selected from the group consisting of aluminum methylethylphosphinate and aluminum diethylphosphinate.

15. The flame retardant polyamide composition according to claim 1 , wherein

R 1 and R 2 may be identical or different and are individually methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl;

R 3 is methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, n-dodecylene, methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene, tert-butylnaphthylene, phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene;

M is an aluminum ion or zinc ion.

16. An article which comprises the flame retardant polyamide composition according to claim 1 .

17. A flame retardant polyamide composition comprising:

(A) 30-76 wt. %, based on the total weight of the composition, of a semi-crystalline semi-aromatic polyamide having a melting temperature (Tm-A) of at least 270° C. which is derived from terephthalic acid monomers and derivatives thereof and at least one diamine selected from the group consisting of butanediamine, hexamethylenediamine and 2-methylpentamethylenediamine;

(B) 2-19 wt. %, based on the total weight of the composition, of at least one semi-crystalline aliphatic polyamide having a number average molecular weight (Mn) of 10,000 to 25,000 g/mol which is at least one selected from the group consisting of polyamide 4,6 (PA-46), or polyamide 4,8 (PA-48) and polyamide-4,10 (PA-410) and copolymers thereof;

(C) 10 to 30 parts by weight (pbw), based on 100 pbw of components (A)+(B), of a halogen free flame retardant system comprising diethyl aluminum phosphinate (DEPAL); and

(D) 5 to 50 weight percent, based on the total weight of the composition, of inorganic fillers and/or reinforcement agents, wherein

the semi-crystalline semi-aromatic polyamide (A) and the semi-crystalline aliphatic polyamide (B) are present in a weight ratio of (A) B) which is in a range of 75:25-94:6, and wherein

the composition exhibits a V0 rating pursuant to UL94V and no blistering when subjected to JEDEC level 2 conditions.

18. The flame retardant polyamide composition according to claim 17 , wherein the semi-crystalline semi-aromatic polyamide (A) consists of polyamide-4T (PA-4T), and the semi-crystalline aliphatic polyamide (B) consists of polyamide 4,6 (PA-46).

19. The flame retardant polyamide composition according to claim 1 , wherein the semi-crystalline semi-aromatic polyamide (A) consists of polyamide-4T (PA-4T).

20. The flame retardant polyamide composition according to claim 19 , wherein the semi-crystalline aliphatic polyamide (B) consists of polyamide 4,6 (PA-46).