PP flat yarn extrusion lines are widely used to produce polypropylene (PP) yarn for woven bags, such as cement valve bags, flour bags, rice bags, fertilizer bags, and shopping bags. Many customers believe that the production output of a high-speed PP tape extrusion line should be the same regardless of the final bag application. However, this is not correct.
The output speed of a PP flat yarn production line depends not only on the machine configuration but also on the raw material formula, especially the proportion of masterbatch and additives.
Although both cement bags and flour bags use polypropylene flat yarn, their raw material requirements are different.
For PP cement valve bags, the material formula usually contains a higher proportion of masterbatch, generally around 10%-20%. The masterbatch improves the color, strength, and processing performance of the yarn. However, a higher masterbatch content may affect the melting and stretching performance of polypropylene material, so the extrusion and stretching speed needs to be adjusted accordingly.
For PP flour bags, the masterbatch ratio is much lower, usually around 1%-2%. Because the material contains a higher proportion of pure polypropylene resin, the yarn has better fluidity and stretching performance. Therefore, the production line can usually run at a higher speed, resulting in higher output.
Flour Bag PP Flat Yarn Usually Has Higher Output
Due to the difference in material composition, the production speed of PP flat yarn for flour bags is generally higher than that for cement valve bags.
For example:
· Cement valve bag PP yarn: Higher masterbatch content (about 10%-20%), requiring a relatively lower production speed.
· Flour bag PP yarn: Lower masterbatch content (about 1%-2%), allowing higher extrusion and drawing speed.
Therefore, even with the same high-speed PP tape extrusion machine, the hourly output may be different when producing yarn for different applications.
Machine Adjustment Is Also Important
Besides raw materials, other factors can influence the final output:
· PP resin quality
· Yarn denier (yarn thickness)
· Drawing ratio
· Heating temperature
· Cooling system efficiency
· Operator experience
A professional PP flat yarn production line should be adjusted according to the customer's final product requirements instead of always running at maximum speed.
For customers producing different types of woven bags, such as cement bags, flour bags, rice bags, or fertilizer bags, choosing the correct machine configuration and optimizing the production parameters are essential for achieving stable quality and high efficiency.
The production capacity of a high-speed PP flat yarn machine is not always the same for every application. Due to differences in raw material formulas, especially the masterbatch ratio, PP flat yarn for flour bags usually achieves higher output than PP yarn for cement valve bags.
Understanding the relationship between material formula and production speed helps customers choose the right equipment and achieve better production efficiency.
