How to produce filler masterbatch (film blowing grade)

1.?Raw?material

Film blowing grade masterbatch is normally made by the LLDPE and CaCO3?compounding. The LLDPE granules?are?recommended to use both high MFI and low MFI, the rate like 25%/75%. The CaCO3?is recommended to choose the powder size D98<6.35 micrometer (2000 mesh), the smaller the calcium powder, the better the film quality. The additive suggest to use Zinc stearate?and?PE wax and white oil.

2.?Pre-mixing

There?is three ways for the different materials pre-mixing or feeding:

1.?High speed mixer

High speed mixer is one kind economic way for different material pre-mixing. We can put all of the LLDPE and CaCO3?and additive into the mixer from low speed to high speed mixing, and discharge it into extruder after reaching the set temperature.

Watch out: the melt temperature of Zinc stearate is 130 degrees, so the mixer temperature needs to set as 105-135 degrees. The mixed material would like something sticking together, not good flowing like powder.

2.?Kneader

Kneader also needs to put all of the material inside for pre-mixing first, and discharge after it well kneads like dough. Comparing with high speed mixer, its advantage is good dispersion ability, especially for high filling rate material. Its disadvantage is high invest cost and consumption and a large area?occupied

3.?Gravimetric feeding system

Gravimetric feeding system is one kind of loss in weight feeding system, it can automatic control the different material feeding into the extruder directly with?less?than 0.5% deviation according to the formula. Its disadvantage is much more higher cost, each one kind of material needs one gravimetric feeder. It’s not recommended for low profit filler masterbatch.

2.?Pelletizing

For the filler masterbatch compounding and pelletizing, the common way is co rotating twin screw extruder with die face hot cutting system or water ring cutting system.?Due to the water absorption character of CaCO3, normally we didn’t recommend to use the pelletizing system which touch with water, that needs to pre-heating the granules when you used it for film blowing or injection etc.

There is one kind of?misunderstanding here, most of the factory want to produce both of PE and PP based filler masterbatch, but due to the characteristics of PP, it would be easy to stick on the die cutting blade, so they recommend strand cutting system with very long air cooling conveyor belt. But actually it cannot good working, firstly it needs longer length to place the conveyor belt (like 24/30 meters); secondly, it cannot let the plastic strands fast cooling down from 200?degrees to less than 50 degrees according to only the room temperature air.

3.?Formula recommend

LLDPE: 12%

CaCO3: 83%

Zinc stearate: 1.5-2%

PE wax: 2-3%

White oil: 0-1%

For more details please contact with us:

Mr. Andy

WhatsApp: +86 18550112020

Email: [email protected]