A polypropylene composite with an intumescent flame retardant and improved UV resistance

Claims

1. A polypropylene composition containing (a) from 20 to 75% by weight of propylene polymer, (b) from 20 to 30% by weight of a halogen-free flame retardant containing nitrogen and phosphorus, (c) from 0.2 to 2.0 wt.% pigment and (d) from 0.2 to 5.0 wt.% additives, based on the total amount of polypropylene composition; where additives (d) contain (d1) from 0.1 to 1.0 wt.% of at least one light stabilizer based on a sterically hindered amine containing NOR fragments (NOR-HALS), and (d2) from 0.1 to 1.0 wt.% of at least one acid scavenger, based on the total amount of polypropylene composition.

2. The polypropylene composition according to claim 1, wherein the propylene polymer (a) is a heterophasic propylene copolymer, preferably a heterophasic propylene copolymer containing - component (a1) polypropylene matrix and - component (a2) an elastomeric propylene copolymer which is dispersed in said polypropylene matrix (a1) and contains units obtained from (i) propylene and (ii) ethylene and / or C4-C20 olefin.

3. A polypropylene composition according to claim 1 or 2, wherein the propylene polymer (a) is a heterophasic propylene copolymer having a melt flow index MFI2(230°C / 2.16 kg), measured according to ISO 1133, in the range of 10 to 200 g / 10 min, preferably in the range of 60 to 200 g / 10 min.

4. A polypropylene composition according to any one of claims 1 to 3, further comprising from 10 to 50 wt.% glass fibre (aa) based on the total amount of the polypropylene composition, preferably short glass fibre having an average fibre diameter of 9 to 15 μm, where the average fibre diameter is determined in accordance with ISO 1888:2006(E) method B.

5. The polypropylene composition according to claim 4, further comprising from 1 to 5 wt.% of an adhesion promoter (ab) based on the total amount of the polypropylene composition, wherein the adhesion promoter is a polypropylene homo- or copolymer grafted with maleic anhydride.

6. A polypropylene composition according to any one of claims 1 to 5, wherein the halogen-free flame retardant (b) containing nitrogen and phosphorus has at least one nitrogen-containing moiety and at least one phosphorus-containing moiety, wherein at least one nitrogen-containing moiety is preferably selected from the group consisting of ammonium, piperazine, melamine, diamine, amide, derivatives and combinations thereof, and / or wherein at least one phosphorus-containing moiety is preferably selected from the group consisting of phosphate, such as orthophosphate; diphosphate; polyphosphate or pyrophosphate, phosphoric acid, polyphosphoric acid, phosphinic acid, phosphorus pentoxide, derivatives thereof and combinations thereof.

7. A polypropylene composition according to any one of claims 1 to 6, wherein the halogen-free flame retardant (b) containing nitrogen and phosphorus comprises from 35 to 40 wt.% melamine polyphosphate and from 50 to 60 wt.% piperazine pyrophosphate, based on the total amount of halogen-free flame retardant.

8. A polypropylene composition according to any one of claims 1 to 7, wherein the pigment (c) is an organic pigment and / or carbon black, wherein when the pigment is an organic pigment, it is preferably selected from a phthalocyanine green pigment and a phthalocyanine blue pigment.

9. The polypropylene composition according to any one of claims 1 to 8, wherein NOR-HALS (d1) is 1,3,5-triazine-2,4,6-triamine, N2,N2'-1,6-hexanediylbis[N4,N6-dibutyl-N2,N4,N6-tris(2,2,6,6-tetramethyl-4-piperidinyl)-, N-allyl derivatives, oxidized, hydrogenated (CAS No.: 1902936-62-2).

10. A polypropylene composition according to any one of claims 1 to 9, wherein the acid absorber (d2) is calcium stearate (CAS No.: 1592-23-0).

11. The polypropylene composition according to any one of claims 1 to 10, further comprising from 0.1 to 0.8 wt.% of at least one UV absorber (d3) containing phenolic hydroxyl groups, based on the total amount of the polypropylene composition, wherein the at least one UV absorber containing phenolic hydroxyl groups is preferably selected from 2-hydroxy-4-n-octoxybenzophenone (CAS No.: 1843-05-6), 2-(4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(octyloxy)phenol (CAS No.: 2725-22-6) and hexadecyl 3,5-bis-tert-butyl 4-hydroxybenzoate (CAS No.: 67845-93-6).

12. The polypropylene composition according to any one of claims 1 to 11, further comprising at least one of from 0.1 to 0.5 wt.% of at least one antioxidant (d4), based on the total amount of the polypropylene composition, and from 0.1 to 0.5 wt.% of at least one metal deactivator (d5), based on the total amount of the polypropylene composition, wherein the at least one antioxidant is preferably selected from octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS No.: 2082-79-3) and tris(2,4-di-tert-butylphenyl)phosphite (CAS No.: 31570-04-4), and the metal deactivator (d4) is preferably 2,2'-oxamido-bis-(ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (CAS No.: 70331-94-1).

13. An article comprising a polypropylene composition according to any of the preceding claims.

14. The article according to paragraph 13, which is part of or is a housing of an electrical device, for example, a housing of a battery, or is part of or is an insulation of an electrical cable, a container or a component of the power electronics of a car or a household electrical appliance.

15. Use of a combination of (i) NOR-HALS and (ii) an acid scavenger to improve the UV resistance of a polypropylene composition containing a halogen-free flame retardant containing nitrogen and phosphorus.