Carbon Black Masterbatch Manufacturers

Black Masterbatch Industry Knowledge Extension

Carbon black masterbatch technology analysis: How to achieve high dispersibility and stable coloring?

Carbon black masterbatch (Carbon Black Masterbatch) is one of the most widely used coloring and functional additives in the plastics industry. Its core challenge is to solve the dispersion problem caused by the high specific surface area and easy agglomeration characteristics of carbon black, while ensuring color stability and functionality (such as conductivity, UV shielding). The following are the key technical points to achieve high dispersibility and stable coloring:

I. Key factors for the dispersibility of carbon black masterbatch

1. Selection of carbon black

Particle size and structure:
The smaller the particle size (such as 20-30nm), the stronger the coloring power, but the greater the difficulty of dispersion (easy to agglomerate).
High-structure carbon black (DBP oil absorption value>120ml/100g) is easier to form a conductive network, but requires stronger shear force to disperse.

Surface chemical modification:
Oxidation-treated carbon black (containing carboxyl/hydroxyl groups) can improve compatibility with polar carriers (such as PA, PET).

2. Matching of carrier resin

3. Dispersants and processing aids

Dispersants:
Low molecular weight polyethylene wax (PE Wax) and stearates (such as ZnSt) can reduce the adsorption between carbon black particles.

Superdispersants (such as BYK-2150) coat carbon black with anchoring groups to improve long-term stability.

Lubricants:
Ethylene bisstearamide (EBS) reduces melt viscosity and prevents screw slippage.

4. Processing technology optimization

Twin screw extrusion process:
High aspect ratio (L/D≥40) + combined screw elements (kneading blocks, reverse threads) enhance shear dispersion.

Temperature zoning control (such as PP-based masterbatch: 180-220℃).

Masterbatch dilution ratio:
Generally, 1%~5% addition is recommended, and conductive masterbatch needs to be higher (10%~20%).

2. Key control points for stable coloring

1. Color consistency
Carbon black concentration and L*a*b* value: Use a spectrophotometer to monitor the blackness (L* value <15 is a high-quality dark black).
Avoid yellowing of the carrier resin: Choose low-volatile PP or add antioxidants (such as Irganox 1010).

2. Adaptability to application scenarios
Outdoor weather resistance: Carbon black itself has UV absorption ability, but it needs to be matched with light stabilizers (such as hindered amine HALS).
Food contact compliance: Carbon black models that comply with FDA 21 CFR 178.3297 or EU 10/2011 (such as Cabot Monarch 880).

3. Common Problems and Solutions