Polymer composition having low sensory impression of smell

Abstract

The present invention relates to a polymer composition having low sensory impression of smell comprising a polypropylene and a calcium salt of phosphoric acid, wherein in said polymer composition the amount of said calcium salt of phosphoric acid is preferably such to accomplish a sensory impression of smell measured according to VDA 270 of at most 4.0.

Claims

1. Polymer composition having low sensory impression of smell comprising a polypropylene, 1-30 wt % of talc, and from 0.2-0.6 wt % of a calcium salt of phosphoric acid, weight percentages based on the weight of the polymer composition, wherein the low sensory impression of smell is at most 4.0 according to VDA 270 (1992).

2. Polymer composition according to claim 1, wherein said calcium salt of phosphoric acid is chosen from the group of tricalcium phosphate (Ca.sub.3(PO.sub.4).sub.2), calcium pyrophosphate (Ca.sub.2P.sub.2O.sub.7), dicalcium phosphate (CaHPO.sub.4) and monocalcium phosphate (Ca(H.sub.2PO4).sub.2).

3. Polymer composition according to claim 1, further comprising any one or more of C2-C3 copolymers, elastomers, impact modifier and reinforcement agents.

4. Polymer composition according to claim 1, comprising wt. % of a polypropylene, selected from the group of a propylene homopolymer and propylene impact copolymer, 0-40 wt. % of a C2-C3 copolymer, 0-20 wt. % of an elastomer, 0-50 wt. % of a reinforcement agent, 1-30 wt % of talc, and 0.2-0.6 wt. % of said metal salt of phosphoric acid, all percentages based on the total weight of said polymer composition.

5. Polymer composition according to claim 1, wherein said calcium salt of phosphoric acid is present in an amount of 0.25 wt. %-0.6 wt. %, based on the total weight of said polymer composition.

6. Polymer composition according to claim 1, wherein said polymer composition is a long-glass fibre reinforced polypropylene (LGF-PP) composition comprising glass fibres.

7. Polymer composition according to claim 6, wherein said long-glass fibre reinforced polypropylene is of the type wire-coated LGF-PP or pultrusion-grade LGF-PP.

8. A method for attaining a sensory impression of smell measured according to VDA 270 of at most 4.0, comprising adding 0.2-0.6 wt % of a calcium salt of phosphoric acid to a polymer composition comprising polypropylene and 1-30 wt % of talc, based on the weight of the polymer composition, to accomplish the sensory impression of smell measured according to VDA 270 of at most 4.0.

9. The method according to claim 8, wherein said calcium salt of phosphoric acid is chosen from the group of tricalcium phosphate (Ca.sub.3(PO.sub.4).sub.2), calcium pyrophosphate (Ca.sub.2P.sub.2O.sub.7), dicalcium phosphate (CaHPO.sub.4) and monocalcium phosphate (Ca(H.sub.2PO.sub.4).sub.2).

10. The method according to claim 8, wherein said calcium salt of phosphoric acid is present in an amount of 0.25 wt. % to 0.6 wt. %, based on the total weight of said polymer composition.

11. Automotive interior article comprising a polymer composition according to claim 1.

12. Automotive interior article according to claim 11, wherein said article is chosen from the group of dashboards, dashboard carriers, door claddings, door fixtures, armrests, pillar cladding, seat cladding, boot cladding interior trims and parts used in heating, ventilation and/or air conditioning instruments.

13. Polymer composition according claim 1, wherein said calcium salt of phosphoric acid comprises tricalcium phosphate Ca.sub.3(PO.sub.4).sub.2, further comprising any one or more of C2-C3 copolymers, elastomers, impact modifier and reinforcement agents.

14. Polymer composition according to claim 13, wherein said polymer composition is a long-glass fibre reinforced polypropylene (LGF-PP) composition comprising glass fibres.

15. Polymer composition according to claim 14, wherein said long-glass fibre reinforced polypropylene is of the type wire-coated LGF-PP or pultrusion-grade LGF-PP.

16. Polymer composition according to claim 13, wherein said calcium salt of phosphoric acid is present in an amount of 0.25 wt. %-0.6 wt. %, based on the total weight of said polymer composition.

Description

EXPERIMENTS

(1) Different polypropylene compositions were prepared according to the list of components mentioned in Table 1 and Table 2. The compositions of Table 1 are based on SABIC PP 612 propylene copolymer. To an amount of about 65 wt % of polypropylene was added a polyethylene (6 wt %) and an ethylene elastomer (8 wt %) so as to form a total amount of 14 wt %. The additives are comprised of antioxidants and stabilisers common in the art. The variations in amount of TCP-SF (calcium phosphate) were corrected by the amount of polypropylene. All amounts are in weight % based on the weight of the polymer composition. The VDA 270 C3 note is the sensory impression of smell. Individual notes of the test panel are also provided herein.

(2) TABLE-US-00001 TABLE 1 Ref. Ref. (1) (2) E1 E2 E2 E3 E4 E5 E6 TCP-SF 0 0 0.1 0.2 0.5 0.5 0.75 1 2 SABIC PP 612 65.05 65.05 64.95 64.85 64.55 64.55 64.30 64.05 63.05 PE and Rubbers 14 14 14 14 14 14 14 14 14 Talc 20 20 20 20 20 20 20 20 20 Additives 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 VDA270 C3 note 4 4 4 3.5 3 3.5 3.5 3.5 4 VDA270 C3 4.0 4.0 4.0 3.0 3.5 3.5 3.5 3.5 4.0 individual 4.5 4.0 4.5 4.0 3.0 3.5 3.5 3.5 4.0 notes 4.0 4.0 4.5 4.0 3.0 3.5 3.5 3.5 4.0 3.5 4.0 3.5 3.5 3.0 3.5 4.0 4.0 4.0 4.0 4.5 4.0 3.5 3.5 3.5 4.0 4.0 4.0 VDA 270 C3 4.0 4.1 4.1 3.6 3.2 3.5 3.7 3.7 4.0 average

(3) Table 2 shows similar experiments based on SABIC PP 513 propylene copolymer in a compound of a somewhat more complex composition. Again the weight of TCP-SF is corrected only via the amount of polypropylene (PP513). All amounts are in weight % based on the weight of the polymer composition.

(4) TABLE-US-00002 TABLE 2 Ref. E7 E8 E9 E10 E11 E12 TCP-SF 0 0.1 0.2 0.5 0.75 1 2 SABIC PP 513 46.85 46.75 46.65 46.35 46.1 45.85 44.85 SABIC PP 612 15 15 15 15 15 15 15 SABIC PP 95610 10 10 10 10 10 10 10 PE and Rubbers 16 16 16 16 16 16 16 talc 10 10 10 10 10 10 10 Additives 2.15 2.15 2.15 2.15 2.15 2.15 2.15 VDA270 C3 note 4 3.5 3.5 3 4.5 4 4 VDA270 C3 individual 4.0 3.5 3.0 3.0 4.0 4.0 4.0 notes 4.5 3.5 3.0 3.0 4.5 4.0 4.0 4.0 4.0 3.5 3.0 4.5 4.5 4.0 4.0 3.0 3.5 3.5 5.0 4.0 3.5 4.0 3.0 3.5 3.0 5.0 4.0 4.0 VDA 270 C3 average 4.1 3.4 3.3 3.1 4.6 4.1 3.9

(5) This table 2 shows that example E10 has a relatively high VDA 270 C3 note. The present inventors believe that this value is an outlier, the exact cause for which could not be established.

(6) The calcium salt of phosphoric acid used in all Examples is tricalcium phosphate TCP SF, supplied by Budenheim. The sensory impression of smell (odor) is provided based on determination according to VDA 270 C3 (1992) meaning that the sample size (Probekrpermenge) is according to variant C, meaning 50+/5 cm.sup.3 (for a 1 liter vessel) or 150+/15 cm.sup.3 (for a 3 liter vessel) and wherein the test is carried out according to variant 3, meaning at a temperature of 80+/2 C. for a time (Lagerdauer) of 2 h+/10 min. A test panel of five people was used, the individual notes have been provided. The VDA 270 C3 note is expressed in half points, following the requirements of this standard. For the purpose of analysis a numerical average has been provided also, such not being strictly conform the standard.

(7) The experimental data supports the finding that the smell (odor) of a polypropylene composition is improved by addition of a calcium salt of phosphoric acid.