The solution of pimples on PVC extrudateThe solution of pimples on PVC extrudate
When pvc granulation, you will find small particles on the products extruded from PVC, sometimes there are no acne, but no reason can be found. The following is technical assistance in formulation and process.
1. Pay attention to the number of resin crystal points. Regular manufacturers produce less "fish eyes", which is one of the main reasons.
2. When using fillers, pay attention to select those after coupling-rheological treatment.
3. It is best to use a filter screen, damping to reduce large-size particles and large crystal points, and often change the screen. The mesh size of the filter should be determined according to the product size and requirements.
4. Pay attention to the processing temperature, cooling, especially the die temperature. Because he is easy to plasticize the crystal points that have been plasticized and re-aggregate here, especially in the presence of certain nucleating substances, there are many small crystal points gathering and forming large crystal points, which is what you call "small acne."
Also from the filler (light calcium):
1. The moisture of the raw materials is too high, the products are extruded under high temperature conditions to evaporate the moisture, causing rough surfaces and graining!
2. The raw material particles are too rough, poor dispersibility, poor compatibility with polymer plastics, and larger agglomerates appear during processing.