Thinker's Guide: Is Your Color Masterbatch Core Dirty? Have You Chosen The Right Twin-screw Extruder?
In the grand narrative of the plastics industry, color masterbatch is regarded as the "soul" of plastic products. However, the carrier of this "soul" - the co-rotating twin screw extruder - is facing the dual challenges posed by the escalation of the global "plastic limit order" in 2026 and the rise of bio-based plastics.
Facing the new challenges of high filling, high dispersion, and high sensitivity, Nanjing Kelongwell Chemical Machinery Co., Ltd., based on data simulation of thousands of screw configurations, will help you understand: how to choose the fateful plastic extruder for making different color masterbatches?
1. Core conclusions
There is no best twin screw extruder; there are only "solutions" that are best suited to the screw configuration and torque level. For the production of color masterbatch, the essence of equipment selection lies in the trade-off between "dispersibility" and "production capacity".
According to the data from the "European Plastics Compounding 2025 White Paper", over 67% of the quality defects in color masterbatch stem from the mismatch between the equipment shear rate and the rheological properties of the material. Therefore, Nanjing Kelongwell advocates: first determine the process, then select the machine type, and finally set the parameters.
2. Three major schools of color masterbatch and equipment selection pyramid
We categorize color masterbatches into three major types, each corresponding to a distinct logic for selecting high-efficiency extruders.
2.1. Category 1: High pigment loading and engineering plastic-based masterbatch - choose the "performance-oriented" "high torque" option
Current background: Since 2025, global titanium dioxide and organic pigment prices have been continuously fluctuating due to geopolitical influences. In order to reduce costs, an increasing number of international customers are attempting to increase the pigment loading to over 50%, and even experimenting with direct addition in engineering plastics such as PA and PC.
Equipment pain point: When faced with high filling (>40%), conventional plastic extruders often exhibit poor dispersion or localized overheating degradation.
· Nanjing Kelongwell solution: At this point, you need a modular co-rotating twin screw extruder, which must be of the high-torque series.
· Data support: According to the data from Kromwell Laboratory, when the specific torque reaches above 12 Nm/cm³ (such as the KLWE series from Nanjing Kromwell), the screw's bearing capacity for high-viscosity melts is improved by 30%, effectively shearing the pigment aggregates to a final dispersed particle size of <20 μm.
· Mandatory configuration: A side feeder and multi-point exhaust must be installed to prevent the "extrusion" phenomenon caused by water absorption in engineering plastics.
· Consideration: When you are attempting to produce PET fiber-grade color masterbatch or PC/ABS alloy color masterbatch, do you often feel that the brightness is insufficient? This is often due to the insufficient torque of the co-rotating twin screw extruder in your current equipment, which cannot provide the necessary "dispersion work".
2.2. Category 2: High-concentration universal masterbatch (such as ABS, PP) - choose the "efficiency-oriented" with "large free volume"
Current background: At the beginning of 2026, the European Union introduced new regulations requiring that the use rate of recycled plastic materials in electronic and electrical appliance casings must reach over 30%. This has led to a surge in market demand for "environmentally friendly color masterbatches" that utilize recycled materials as carriers.
Equipment pain points: The recycled materials contain many impurities and exhibit significant density fluctuations, often necessitating the addition of large amounts of calcium carbonate or talcum powder to reduce costs.
· Nanjing Kelongwell plan: An efficient extruder with a large aspect ratio (L/D > 48:1) should be selected.
Why? A larger aspect ratio means a longer residence time. For filled masterbatches that require "gentle mixing", excessive shear can damage the carrier's fluidity.
Case: Nanjing Kelongwell customized a parallel co-rotating twin screw extruder for a recycling giant in Europe. By optimizing the screw combination (introducing a large lead conveyor block + toothed disc), the output increased by 22% compared to traditional equipment while ensuring 60% talcum powder filling.
· Thought: When you use recycled materials as a substitute for "new materials", are you troubled by odor or filter pressure issues? This is actually the ultimate test for the exhaust efficiency of the twin screw extruder and the smoothness of the filtration system.
2.3. Category 3: Special functional masterbatch (degradable, antistatic, slippery) - choose "high precision" and "control-oriented"
Current News: In the third quarter of 2025, global bioplastics production capacity surged, and new breakthroughs were made in the heat resistance and processing window of degradable materials such as PLA and PBAT.
Equipment pain point: Degradable plastics are extremely sensitive to temperature, and shear heat often leads to material degradation.
· Nanjing Kelongwell scheme: A twin screw extruder equipped with a precise temperature control module (±1℃ accuracy) and low-shear screw elements must be selected.
· Authoritative citation: Citation from the 2025 review in the Journal of Polymer Compounding: "For reactive extrusion or degradable masterbatch, the modular design of the threaded elements of a co-rotating twin screw extruder is the only way to achieve controllable chemical reactions.".
· Q&A session:
Q: I want to make PLA smooth masterbatch, but the screen always gets clogged. What should I do?
Answer: This issue is typically not related to the filter screen, but rather insufficient melt strength. Nanjing Kelongwell recommends adopting "low-temperature extrusion" technology in the later stage of the twin screw extruder. By adjusting the screw speed and feed ratio, the melt temperature can be controlled 15°C below the material degradation temperature, maintaining melt strength and naturally resolving the screen blockage issue.
3. New variables of equipment that you cannot ignore in 2026
When you decide to purchase a plastic extruder, in addition to the aforementioned process matching, Nanjing Kelongwell reminds you to pay attention to the following three "hidden data":
3.1. Specific torque: the "gold standard" for measuring the progressiveness of extruders
According to data from the Institute of Plastics Processing (IKV) at the RWTH Aachen University in Germany, the specific torque of the world's leading co-rotating twin screw extruders has generally reached 11-13 Nm/cm³. Nanjing Kelongwell's high-efficiency extruder series has fully met this standard. Equipment with low specific torque can only reduce production speed when faced with high filling, akin to a "small horse pulling a large cart".
3.2. Specific power and specific output
Key Q&A:
Q: Why is it that the same 50-model machine can achieve a production rate of 200kg/h for others, but only 150kg/h for me?
Answer: The key lies in "specific power", which reflects the efficiency of the extruder. Nanjing Kelong Weir maximizes the efficiency of converting mechanical energy into shear heat by optimizing the meshing gap of the co-rotating twin screw extruder, ensuring you achieve the highest output per unit of energy consumption.
3.3. Digitalization and process database
Today's high-efficiency extruders are no longer just cold steel machines. Nanjing Kelongwell provides equipment for international customers with a built-in "color masterbatch process package". Simply input your carrier (PP/PE/PET) and filling amount, and the PLC system will automatically retrieve the historically optimal combination of screw speed and temperature curve. This is the best shortcut for customers who are trying to modify "new materials" for the first time to quickly bypass the "trial and error period".
4. Conclusion
Producing color masterbatch is actually a microscopic battle about "shearing and fusion". Choosing the co-rotating twin screw extruder from Nanjing Kelongwell Chemical Machinery Co., Ltd. is not just choosing a piece of equipment, but also a market-proven solution for mixing and extrusion.
In today's era where environmental protection and performance are both prioritized, let professional equipment handle complex formulations, while you focus on defining the colors of the market. If you are contemplating how to enhance the quality of your existing masterbatch, or planning to venture into new areas such as degradation and high filling, it may be worthwhile to re-examine your "core" asset - the twin screw extruder.
