How to create a two coloured Rotational Moulded PE product

Rotational Moulding offers great flexibility and almost unlimited options. However, there are still some limitations when it comes to design possibilities.

Many projects require multi coloured products that would be perfectly manufactured with Rotational Moulding.

Multi coloured products are currently manufactured by adding various different coloured powders in specific areas of the tool, with the aim of preventing a homogeneous mix. This process has its limitations, especially when it comes to large items, and very rarely the final outcome can be predicted. No accurate distinction can be achieved between two colours when desired.

Lysis Technologies, have been working very closely with the rotational moulding industry across Europe and have responded to the demand for a perfectly multi-coloured moulding.

In this case study we will present the creation of a two-coloured product, developed with Polymer Developments UK Ltd

The product

The item is of approximate dimensions 1.7m by 0.5m by 0.2m. The top part is required to be of grey colour and the bottom is white.

The process

Rotational moulding is proven to be more efficient, as it is quicker and cheaper. The product is of high quality and weather resistance.

The way forward was to apply the colour-matched Lysis Technologies in-mould sprayed ink system. Polymer Developments applied their spraying skills and knowledge. Half of the mould was coated in the desired grey colour, using a spray gun.

Then, the tool was charged with PE powder and the rotational moulding process was carried out as normal. The result was a perfect two-colour polyethylene rotational moulded product, exhibiting a well-defined line between the coloured and non-coloured area (see fig. 1).

Figure 1: Perfect two-coloured polyethylene rotomoulded product

Benefits of the technology

Some of the benefits of the in-mould sprayed ink system from Lysis Technologies are the following:

Colour Customisation
Permanent result
Solvent, UV and weather resistance
NO aerosol cans to be used
Quick and easy application
Perfectly finished products
Cost Reduction in the overall process.
Other examples of products achieved with in-mould spray coating are on figures 2 and 3.

Figure 2: Perfect two-coloured polyethylene rotomoulded item with black ink system and white PE powder.

Figure 3: Perfect two-coloured polyethylene rotomoulded item with grey ink system and purple PE powder

Case Study – as featured on the BPF website here

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