What are the special requirements for the formula and addition ratio of white masterbatch for different types of white injection molding pellets during injection molding?

In injection molding, different types of white injection molding pellets (such as PP, ABS, PC, etc.) have their own requirements for the formula and addition ratio of white masterbatch, mainly because of their differences in chemical properties, processing temperature, thermal stability and performance requirements of the final product. The following is an analysis of the special requirements for the formula and addition ratio of white masterbatch for different plastic substrates:

Injection Molding White Masterbatch White Injection Plastic Granules

1. Polypropylene (PP)
Formula requirements:
Pigment selection: The processing temperature of PP is relatively low (about 200-250°C), so white masterbatch usually uses titanium dioxide (TiO₂) with moderate heat resistance as the main pigment. Titanium dioxide has good hiding power and whiteness, and has good compatibility with PP.
Dispersant and carrier: In order to ensure the uniform dispersion of titanium dioxide in the PP matrix, an appropriate amount of dispersant (such as polyethylene wax or calcium stearate) is usually added. The carrier resin should also match the melt index and processing temperature of PP.
Stabilizer: Add an appropriate amount of antioxidant and light stabilizer to improve the weather resistance and service life of PP products.
Addition ratio:
Usually in PP injection molding, the addition ratio of white masterbatch is 2%-5%, and the specific ratio depends on the required whiteness and hiding power. Too high an addition ratio may lead to poor dispersibility and affect the fluidity of the plastic.

2. Acrylonitrile-butadiene-styrene copolymer (ABS)
Formula requirements:
Pigment selection: The processing temperature of ABS is relatively high (about 220-260°C), so the titanium dioxide in the white masterbatch needs to have higher heat resistance. At the same time, the particle size of the pigment should be finer to ensure uniform dispersion in the ABS matrix.
Dispersant and carrier: Due to the high processing temperature of ABS, the dispersant needs to have better thermal stability and compatibility. The carrier resin usually selects materials with similar chemical properties to ABS, such as ABS or modified polystyrene.
Stabilizer: Add an appropriate amount of heat stabilizer and antioxidant to prevent ABS from degrading during high-temperature processing.
Addition ratio:
For ABS injection molding, the addition ratio of white masterbatch is generally 3%-6%. A higher addition ratio can provide better whiteness and hiding power, but it is necessary to ensure the dispersibility of the pigment to avoid affecting the mechanical properties of ABS.

3. Polycarbonate (PC)
Formulation requirements:
Pigment selection: The processing temperature of PC is very high (about 260-300°C), so the pigment in the white masterbatch must have extremely high heat resistance and chemical stability. Titanium dioxide is the preferred pigment, but it needs to be specially treated to improve its heat resistance and dispersibility.
Dispersant and carrier: Due to the high melt viscosity of PC, the dispersant needs to have good lubricity and dispersibility. The carrier resin usually selects materials with good compatibility with PC, such as PC or modified PC.
Stabilizer: Add high-performance antioxidants and light stabilizers to ensure the stability of PC products in high-temperature processing and long-term use.
Addition ratio:
In PC injection molding, the addition ratio of white masterbatch is usually 2%-4%. Due to the high transparency of PC, a lower addition ratio can achieve good whiteness and hiding power. At the same time, too high an addition ratio may affect the transparency and mechanical properties of PC.

4. Polyvinyl chloride (PVC)

Formula requirements:

Pigment selection: The processing temperature of PVC is relatively low (about 160-200°C), but the chlorine resistance and weather resistance of the pigment are required to be high. Titanium dioxide is a commonly used pigment, but an appropriate amount of stabilizer needs to be added to prevent PVC from decomposing during processing.

Dispersant and carrier: The dispersant needs to have good lubricity and dispersibility to ensure uniform distribution of the pigment in the PVC matrix. The carrier resin usually selects materials with good compatibility with PVC, such as PVC or modified PVC.

Stabilizer: Add an appropriate amount of heat stabilizer and light stabilizer to prevent PVC from discoloring and degrading during processing and use.

Addition ratio:
In PVC injection molding, the addition ratio of white masterbatch is usually 3%-5%. Due to the low processing temperature of PVC, the dispersibility of the pigment is particularly important, and the optimal addition ratio needs to be determined through experiments.

5. Nylon (PA)
Formula requirements:
Pigment selection: Nylon has a high processing temperature (about 250-280°C), and has strict requirements on the heat resistance and chemical resistance of the pigment. Titanium dioxide is the main pigment, but it needs to be specially treated to improve its heat resistance and dispersibility.
Dispersant and carrier: Due to the strong hygroscopicity of nylon, the dispersant needs to have good moisture resistance and dispersibility. The carrier resin usually selects materials with good compatibility with nylon, such as nylon or modified nylon.
Stabilizer: Add an appropriate amount of antioxidant and moisture-proof agent to ensure the stability of nylon products during processing and use.
Addition ratio:
In nylon injection molding, the addition ratio of white masterbatch is usually 3%-5%. Due to the high mechanical property requirements of nylon, the addition ratio needs to minimize the impact on mechanical properties while ensuring whiteness.