The FAQ about master batch manufacturing machine producing color master batch
Q: If want to make the PP color masterbatch with more than 40% carbon black content, but it is easy to break and pollute. what should I do?
A: ①From the point of view of the process, the main reasons and solutions are as follows:
- As carbon black is difficult to disperse, it is very difficult for carbon black content to reach more than 30% if the color masterbatch is prepared by an ordinary twin-screw extruder. Twice granulation can be used and human carbon black can be added in batches.
- By adjusting the formulation process, lubricants or dispersing aids can be added appropriately to help carbon black to disperse, thereby increasing the proportion of black added. Using a two-stage extruder, the functions of dispersion and extrusion of the equipment are decomposed through suitable extruder to achieve the purpose of carbon black dispersion. For example, GTS75/180 + high-mixer can be used together. Firstly, PP and 30% carbon black are pre-mixed through the high-mixer, and then added to the twin-screw 75 extruder machine. The 75 extruder machine can also add the remaining 10% carbon black to machine 75 by increasing the length-diameter ratio and increasing the side feeder. After distributing and mixing, the materials enter into the next-stage single-screw 180 machine, and carry out cooling extrusion.With such above solution,the produced final pellets are well dispersed, have high density and high concentration.
- The carbon black dispersing ability can be increased through special screw elements. For example, to make the screw element similar to the structure of the internal mixing rotor in the Banbury mixer. Its strengths and advantages are achieved through special functional elements with low shear and high dispersion. The edges and corners of the carbon black molecular structure are avoided from being damaged, thereby improving its mixing efficiency with PP materials.
- The addition of carbon black content to 40% can be easily achieved through three-screw equipment.
Using a three-screw extruder can also achieve 40% carbon black mixing and extrusion, which has the advantages of low energy consumption, low investment, and small production line footprint. (photo as below for reference)
- Dry carbon black masterbatch is really dirty, if conditions permit, it is best to use internal mixer, carbon black content can reach 50%.
- If you consider hot cutting, there will be no problem of bar breaking.
②The ways to solve the problem from the point of view of formula are:
- Using base material with high flow performance. Compounding of polymer dispersant and common dispersant.
- Can consider the use of color paste production, dust will be much less.
Q: When the modified ASA masterbatch is used for surface co-extrusion, there will be a lot of small pits like hemp spots after polishing, which are very small and occasionally appear, and the severity of processing with different equipment is different. What is the reason for this? Is there a solution?
A: It may be the problem of blending, such as uneven mixing, poor dispersion, etc. The compatibility is not good. The following solutions are provided for this issue:
- Dry the material thoroughly.
- Adjust the appropriate co-extrusion temperature.
- Extruded ASA layer should not be too thin.
- The operation of extrusion should be correct.
- The influence of floating calcium should be avoided.
Q: The antioxidants used in color masterbatch seem to be very few. Is it necessary to add it?
A: Color masterbatch generally need to add some antioxidant system, lubricant will also add some, not in excess are very few.
Under the action of high shear, the masterbatch without the protection of antioxidant system will make the color yellow, and the masterbatch will also degrade, at the same time, the properties of the material will be reduced, so it will not be able to stretch and granulate.
One of the main uses of antioxidants is to prevent discoloration and oxidative decomposition.
However, due to the high price of antioxidants, considering the cost and other factors, whether and how much antioxidants are added to the color masterbatch mainly depends on the processing needs of downstream customers and which products to apply the color masterbatch to.
If the product is used outdoors, add antioxidants as well as UV stabilizers; if customers have requirements for anti-aging, make the color masterbatch antioxidant system concentrated.
In short, under the premise of no special requirements and guaranteed performance, in order to increase the profit space of the enterprise, the antioxidants in the color masterbatch can not be added in principle, but they should be added to the color masterbatch of engineering plastics such as PA and ABS, and there are many weather-resistant color masterbatch used in engineering plastics.
In addition, generally do fiber-grade color masterbatch to add some antioxidants.
Q: how to test the density of color masterbatch? There are many methods in the industry, and the results obtained by different methods vary greatly. Is there a better and correct test method that can quickly measure the density of excellent masterbatch?
A: The accurate test method of color masterbatch density is as follows:
- The density bottle method is used to measure, the operation requirement of this method is very high, there can be no bubbles, and the test temperature also has a certain influence on the density.
- The density gradient meter is used to measure, which is accurate and easy to operate.
- It is measured by an electronic hydrometer suitable for solids, also known as the electronic specific gravity balance, based on Archimedes’s law, which can be accurate to four digits.