Patent ID: 11920034
Assignee: BASF SE
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A polyamide composition (P) for the production of molded parts, wherein the polyamide composition (P) comprises:
(a) 25 to 85 wt.-%, based on the total weight of the polyamide composition (P), of polyamide (A);
(b) 15 to 75 wt.-%, based on the total weight of the polyamide composition (P), of at least one flat glass fibre (B) with elongated shape having a non-circular cross-sectional area;
(c) 0 to 30 wt.-%, based on the total weight of the polyamide composition (P), of at least one reinforcement agent (C) different from the flat glass fibre (B),
(d) 0 to 30 wt.-%, based on the total weight of the polyamide composition (P), of at least one additive (D);
wherein
the at least one polyamide has a viscosity number (VN), measured according to ISO 307 in a 0.005 g/ml solution in 90 wt.-% formic acid at 25° C., in a range of from 80 to 200 mL/g;
the at least one flat glass fibre (B) as comprised in the polyamide composition (P) is defined by the following parameter:
(i) an aspect ratio of the length of a main cross-sectional axis w to the length of a secondary cross-sectional axis d of the non-circular cross-sectional area of the flat glass fibre (B) is from >3 to 10;
(ii) an average length Lz of the flat glass fibre (B), defined by the following formula (1), has a minimum value of 400 μm and a maximum value of 700 μm:

Lz=Σi=1n(Li)3ni/Σi=1n(Li)2ni  (1),

wherein:
Li is the length of the largest dimension in one of the spatial directions of a fraction of the flat glass fibre (B) in the polyamide composition (P),
ni is the number of flat glass fibres (B) having the length Li,
n is the total number of flat glass fibres (B), and
i is an integer from 1 to ∞; and
(iii) a ratio between an average longest dimension Ln, defined by the following formula (2), of the flat glass fibre (B) and a shortest average dimension d of the flat glass fibre (B) is

  
    
      
        L
        n
      
      d
    
    ≥
    
      4
      ⁢
      0
    
  
  :

Ln=Σi=1nLini/Σi=1nni  (2),

wherein:
Li is the length of the largest dimension in one of the spatial directions of a fraction of the flat glass fibre (B) in the polyamide composition (P),
ni is the number of flat glass fibres (B) having the length Li,
n is the total number of flat glass fibres (B),
i is an integer from 1 to ∞, and
d is the length of the shortest dimension in one of the spatial directions of a fraction of the flat glass fibre (B); and
wherein the polyamide composition (P) comprises no other polyamide than PA 6.6.