Metall Effect Pigments for reduced Flow Lines, their Manufacturing and Machine Technology
Patent 18044/TUB

This Invention enables a possibility for manufacturing Metall effect plastic articles without visible flow lines.

  1. Eliminated flow lines in effect pigment filled polymer parts, independant of the part geometry
  2. Simple pigment manufacturing
  3. Large variety of possible pigment particle geometries
  4. Suitable for common injection moulding and extrusion
Possible Applications

Colouring of plastics to achieve metallic apperarance.


Filling polymers with metal effect pigments is a key technology to achieve metallic appearances of injection moulded polymer parts while avoiding additional coating steps. Conventionally, metallic appearance is generated due to the orientation of planar metal effect pigment particles in the flow direction of the polymer melt, usually parallel to the part surface in order to reflect light to the viewer. Nevertheless, where polymer fronts merge, the particle orientation is disturbed (Fig. 1), resulting in locally enhanced light scattering and thus creating dark streaks in the solidified polymer part, called flow lines.

Technical Description

The invention presented here solves this problem by introducing novel pigment particle geometries, preferably such as tetrahedrons, pyramids and cubes. By the geometry, the degree of parallel particle orientation can be regulated and the flow line visibility reduced (Fig. 2). Moreover, the degree of the flop can be regulated. There are broad varieties of possible manufacturing methods of the novel metal effect pigments such as cold forming, rolling, pressing, molding, and machining. The pigments, consisting of aluminium, copper, brass or coated polymer, can be used in common polymer processing, such as injection molding and extrusion.

Contact Us

Ina Krüger

Technology Transfer Manager

+49 (0)30 314-75916

Technology Readiness Level

Technology validated in lab

Property Rights

pending: CN, US
approved: CH, DE, FR, GB, LI

Patent Holder

Technische Universität Berlin

Possible Cooperation
  • R&D Cooperation
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