What Plastic Pigments are Used in Rotational Molding?

Plastic pigments are organic or inorganic additive particles added to the polymer(resin)to give a specific color or functional properties the plastic products.

The application of pigments in rotational molding is for coloring. Plastic colorants are important to create both visual appealing and functional products. Types of plastic colorants mainly used in rotomoulded plastic products include masterbatches, colored pellets, colored compounds, Dry Color, Paste Colors, and Liquid Masterbatch. They are mixed with natural resin in powder form and rotational molding to shape. The plastic colorants have three significant characteristics of hue, lightness and saturation.  

Let’s take a look at the major performance properties of plastic colorants in plastics applications.

Coloring strength and color fastness

Plastic colorants give various colors to products, and also create the exterior images and impression in the daily life. It requires to meet the specified fastness criteria. The effect of coloring is most noticeable in the decorative products. It can artfully give a feeling of luxury and dignity, for example, the industries like cosmetics, home appliances, and automobile interiors have high requirement in the appearance.

Weather resistant and light fastness

Exposure to sunlight and some artificial lights can have adverse effects on the lifespan of plastic products. It require weather resistant and light fastness. Polymers used outdoors frequently require UV protection and weather resistant pigments. For example, rotomoulded plastic products like remote control electric lifebuoy requires weather resistance like temperature change, wind, and rain.

Other requirements include acid and alkali resistance, electrical properties conductivity,anti static performance  and more properties depending on the specific applications.

While choosing pigments for rotomoulded plastic products, there are definitely a few important technical performance requirements to keep in mind.

• Heat Resistance
• Migration resistance
• Dispersion
• Oxidation resistance
• Moisture content
• Compaction
• Mechanical properties of materials
• Processing temperature
• Melt flow rate

It also needs to satisfy the environmentally friendly requirement of RoHS

Choosing the suitable plastic pigments and colorants for rotational molding is also critical to produce high quality rotomoulded plastic products. Be sure to check out our article about how to choose the best pigment for rotational molding.