Metallic Effects in Plastics
The best way to create attractive metallic effects in plastics is to tint plastics with aluminum pigments. The optical effects of metallic pigments depend on shape, particle size and concentration of metallic particles.
For many manufacturers, the first appeal is the cost effectiveness of metallic effects in plastics; as when compared to coating components.
ECKART offers a comprehensive portfolio of aluminum pigment preparations for many polymer materials and manufacturing processes.
Mass coloration of injection molded parts is more cost efficient than the coating of plastic parts. Savings are achieved without compromising optics. Metallic pigment preparations for plastics offer alternatives to coatings for manufacturers in automotive and home appliances industries.
Silver metallic mass coloration gives your application the appearance of solid metal. Therefore, it provides the allure of perceived value.
Further advantages include:
- No added coatings step necessary.
- No VOCs.
- No overspray.
- Scratch resistant; whole part is solid colored.
Optical effects depend on the shape, particle size and concentration of the pigments. Combinations of these characteristics will provide varieties of silver shades:
- Brightness - bright to dark metallic appearance.
- Effects - Smooth and structureless to a classy sparkle.
- Dimensions - Illusions of three-dimensional depths.
- Shine - shimmering shades with an impressive shine.
We differentiate the shape of aluminum pigments between “Cornflake” and “Silverdollar” grades.
Cornflake grades have good hiding power. However, cornflake pigments offer relatively dark optical effect.
Silverdollar pigments a good brightness and outstanding metallic gloss, they show a lenticular geometry. High performance applications like automotive, electronics industry and cosmetic packaging use Silverdollar pigments.
The main differentiation between grades is particle size. ECKART offers silver metallic pigments between 6 and 325 microns. The choice depends on the desired effect.
The quality of the aluminum pigment is higher as narrower the particle size distribution is. Very narrow particle size distribution guarantees the best optical properties.
Mixtures with chromatic pigments end up in nice metallic effects in any imaginable color. Combinations with other effect pigments like pearlescent pigments creates attractive stylings. The variations are uncountable.
Metallic gloss can be improved by raising the concentration. Usual concentrations of effect pigments in polymers are between 0,1 and 5%.
The opacity of the polymer has some influence, the best effect can be achieved with transparent polymers. Opaque polymers need higher pigmentation rate.
Our brand MASTERSAFE represents effect pigments in pellet form. MASTERSAFE was developed to maximize convenience and safety. One of the pellets’ main advantages is the easy and homogeneous dispersion in the polymer matrix.
MASTERSAFE products were specifically designed for the manufacturing of masterbatches. The carrier is compatible with a wide range of thermoplastics, solvent free as well as odorless.
The food approval is another decisive characteristic of our MASTERSAFE pellets.
The key advantages of MASTERSAFE pellets in comparison with powders and pastes are:
- Dust-free and therefore easy and safe handling.
- Automatic metering.
- Easy to disperse.
- Low odor.
- Free of solvents.
- Excellent storage stability.
- Suitable for food packaging in many countries.
The pigment content in all MASTERSAFE pellet products is always 80 %.
STAPA® WM Reflexal
STAPA® WM Reflexal is another dust-free pigment preparation series for tinting plastics. This product series uses white oil as carrier. It shows good wettability, has no impact on the production process and is suitable for food packaging. STAPA® WM Reflexal can be used for homopolar resins. The carrier has higher boiling temperature than the polymer; it remains in the finished goods.
STAPA® DL Reflexal
For polar resins and liquid masterbatches, ECKART offers another solution: STAPA® DL Reflexal. The carrier is epoxidized soy oil, which is also compatible with PVC, but phthalate–free.
In our STAPA® series, many different particle sizes are available, just like in our MASTERSAFE range. The carrier content is generally 20% in all pigment preparations.
Dry Aluminum Pigment Powders
Dry aluminum pigment powders can also be used as a colorant for plastics. Here, it is essential that safety rules are carefully respected: Fine aluminum powder can cause dust explosion. Coarser pigments in powder form (more than 60 microns) are safe, they do not count among dangerous goods.
All effect pigments are shear sensitive. During all manufacturing steps (mixing, extrusion, processing), only a minimum shear force should work on the pigments. Otherwise, the effect might be reduced or even destroyed. Metallic pigments are very easy to disperse in polymers, consuming little energy.
Contact a Metallic Effects in Plastics Professional
Our technical service team is ready to help you with any questions regarding the use of metallic effect pigments in plastics applications.