Geoglit® SP – artificial marble effect pigments for injection moulding

Blog Archive | 3 minutes  | Author: Koen Nickmans , Ph.D.

Special effects for injection moulding

Injection moulding is a manufacturing technique by which thermoplastics are melted via an extruder and moulded into various shapes. Now a cornerstone of modern manufacturing, injection moulding has enabled the high-speed production of lightweight and cost-effective plastic parts, ranging from disposable consumer goods to high precision engineering components.

One of the prevalent consumer trends in plastic part production in recent years has been a shift toward plastic materials that look and feel ‘natural’, whilst maintaining the advantages associated with injection moulding: excellent processability, throughput, and consistency. As a result, colourists working in the plastics industry are actively emulating various natural aesthetics through clever formulation and the use of innovative effect pigments. For example, speciality pigment flakes are used to create marbled surfaces that emulate natural stone such as granite. This effect is used to create a luxurious look in various household articles such as bench tops. Similarly, textured metallic parts have found applications ranging from vacuum cleaner frames to espresso machines.

While the range of available natural and textured aesthetics that can be achieved with injection moulding is continually expanding, the options are still relatively limited compared to other applications areas such as coatings (inks, paints) and cosmetics. In these applications, the textured effects are achieved using pigments manufactured from reflecting polyethylene terephthalate (PET) films. Unfortunately, PET-based pigments have thus far been incompatible with the high temperature associated with the injection moulding process, due to their low melting point of approx. 160 °C. For this reason, most speciality pigments used for texturing thermoplastics are nowadays manufactured from aluminium foils.

Aluminium-based pigments are temperature stable up to 240 °C, but the variation in the possible visual effects using this material is limited. Further complicating their use, aluminium pigments are coated with a polyurethane resin, which can be damaged by the high shear conditions of the extruder. As a result, aluminium pigments must be carefully processed to limit adverse effects such as colour fading during extrusion and colour bleeding.


Injection moulded cars using Geoglit SP White

Figure 1: Geoglit® SP glitters are ultra stable PET-based glitters that are especially suited for injection moulding. Using the Geoglit® SP White it is now possible to offer a white sparkle in a grey or black background.


Marble effects with high-temperature stable Geoglit® SP glitters

Our supply partner GEOTECH, one of Europe’s leading speciality pigment manufacturers, has now developed a new range PET-based pigments which are compatible with injection moulding.  The Geoglit® SP range consists of ultra stable black and white glitters which are temperature stable up to 220 °C. In contrast to aluminium-based glitters, the Geoglit® SP glitters do not make use of any coating layer. Instead, the black and white colour is incorporated directly into the PET foil via a newly developed proprietary process. Since there is no coating layer, the Geoglit® SP glitters are also very stable toward shear forces in addition to the high-temperature resistance. Figure 1 shows sample moulded parts using the Geoglit® SP glitters. Using the Geoglit® SP White it is now possible to offer a white sparkle in a grey or black background.

Geoglit® SP Black and SP White initially come in 3 different particle sizes: 008 HEX (200 micron), 015 HEX (400 micron) and 025 HEX (600 micron). Geoglit® SP White is also available in a fibre shape. Geoglit® SP Black and SP White are non-toxic and comply to global regulations for plastics.


Injection moulded cars using Geoglit SP Black

Figure 2: Geoglit® SP is available in a range of particle sizes and shapes (008 HEX, 015 HEX, 025 HEX, and fibres).  Geoglit® SP Black can be used to create a marbling effect in injection moulded plastics.


Contact us

Please get in touch if you want to learn more about this new product line for the next generation of artificial marble effects or if you would like to request any samples.

Author: Koen Nickmans , Ph.D.

Koen studied chemistry at the Catholic University of Leuven in Belgium with a specialisation in polymers. He subsequently obtained a PhD in the field of responsive polymeric coatings from the Eindhoven University of Technology in the Netherlands. He has been with Lawrence Industries since 2019 as a technical sales manager, covering all areas involving polymers: thermoplastics, thermosets, and elastomers.