Masterbatch is a special colorant for polymer materials, commonly used in plastic products. It is composed of three basic elements: pigments or dyes, carriers and additives.
Pigments are further divided into organic pigments and inorganic pigments.
Commonly used organic pigments include: phthalocyanine red, phthalocyanine blue, phthalocyanine green, light-fast red, macromolecular red, macromolecular yellow, permanent yellow, permanent purple, azo red, etc.
Commonly used inorganic pigments include: cadmium red, cadmium yellow, titanium dioxide, carbon black, iron oxide red, iron oxide yellow, etc.
The carrier is the matrix of the masterbatch. For special masterbatch, the same resin as the product resin is generally selected as the carrier. The two have the best compatibility, but the fluidity of the carrier must also be considered.
Additives such as dispersants can promote the uniform dispersion of pigments and no longer agglomerate. The melting point of the dispersant should be lower than that of the resin, have good compatibility with the resin, and have good affinity with the pigment. The most commonly used dispersants are: polyethylene low molecular weight wax and stearate. There are also some additives that can increase the characteristics of the masterbatch in certain aspects, such as flame retardant, brightening, antibacterial, antistatic, antioxidant and other types of additives.
Why do we need to make pigments into masterbatch for coloring?
Since masterbatch is composed of dyes and other substances, why not directly use dyes and other substances to dye products, but create excellent masterbatch for indirect coloring?
There are five main reasons:
Masterbatch has better colorability
During the production process of the masterbatch, the pigments are refined and the super-normal amount of pigments are evenly loaded into the resin. The aggregates produced can be called pigment concentrates, so their tinting power is higher than of the paint itself.
Masterbatch has better dispersion
Due to the refined processing using carriers such as resin and additives such as lubricants, the pigments have been well pre-dispersed during the preparation of the masterbatch, making the coloring of the masterbatch more dispersible. Moreover, the masterbatch and the materials of plastic products are easier to mix, which also makes the coloring of the masterbatch more uniform. If you directly use pigments to color plastic products, the products may be unevenly colored or the color may easily fade. The smaller the particle size of the pigment, the higher its tinting power.
The meaning of pigment dispersion: Pigment dispersion means that the pigment particles are fully refined. Refinement and dispersion is the process of breaking up pigment agglomerates or agglomerates and minimizing their particle size. The dispersion of pigments not only affects the appearance (spots, streaks, gloss, color and transparency) and processability of colored products, but also directly affects the quality of colored products, such as strength, elongation, chemical resistance and resistivity.
Our testing studies show that as the pigment particles decrease, the impact strength and elongation of the product also increase:
- If the pigment particle size is greater than 30 μm, spots and streaks will appear on the surface of the product;
- 10-30 μm, the surface of the product is matte;
- When the particle size is less than 5 μm, it can be used for general products, but for products with strict requirements, it will also affect their mechanical properties, electrical properties and processability;
- For fibers (single filament diameter 20-30 μm) and ultra-thin films (less than 10 μm), the pigment particle size is less than 1 μm.
Masterbatch has more consistency
The amounts of masterbatch particles and resin particles are similar, so the metering and mixing can be relatively uniform. It can more conveniently and accurately adjust the measurement to ensure the stability of the color and the stability of the coloring. Direct use of pigments may cause color spots or darkening of the product surface.
Masterbatch storage stability is higher
During the storage and use of pigments, pigments will absorb water and oxidize. Since the resin carrier plays a role in separating the pigment from air and water, and the additives such as lubricants added to it can also increase the stability of the pigment, when the pigment is made into masterbatch, the color of the masterbatch pigment can be improved. The quality remains unchanged for a long time.
Masterbatch is easier to measure and use
Masterbatch particles are similar to resin particles and are more convenient and accurate in measurement. It will not adhere to the container when mixed, and the mixture with the resin is also relatively uniform, which can ensure the stability of the added amount and the color of the product. The pigments used are generally in the form of powder, which is easily dusty and affects the cleanliness of the operating environment. Inhalation by the operator will also affect the health of the operator.
Masterbatch is widely used in the plastic industry to provide different colors and appearance effects for plastic products. In addition to coloring, masterbatch can also have several functions at the same time. Manufacturers will recommend users to add some additives according to the needs of the product, such as adding certain additives to the color masterbatch to make it flame retardant, brightening, antistatic, antioxidant, anti-ultraviolet and other functions.
In the production and manufacturing process of masterbatch, there are a series of complex technological processes. If you want to know about the production process of masterbatch, you can click here to read our other article: Masterbatch Manufacturing Process