Process problems and solutions of PVC transparent sheet （PVC rigid film）extrusion production

PVC transparent sheet is one of the main varieties of rigid PVC film, and this article mainly shares the problems and solutions that tend to occur in extruder machine production.

The problems commonly encountered in the production process of PVC sheets are bubbles, more crystal points, yellowing of sheet colour and other issues.

We are a supplier of PVC tin stabilizers in PVC sheets production, this article is based on our years of service experience, we are not a professional PVC sheet manufacturer, please understand if there are any mistakes.More details can contact us free, we have a professional engineer to help you solve your problems. Including the latest calendering production.

Color Yellowing Problem:

The causes and solutions are:

1.First, the PVC itself is poorly stabilized

If it is a new PVC resin manufacturer, it may be that the PVC itself is poorly stabilized and can be changed to try out the PVC. However, even if the brand PVC that has been used, it may be caused by the PVC resin itself, because even if the PVC produced by the same manufacturer, different batches, there may be differences in quality.

2.Second, the stabilizer is not stable enough.

3.Third, the temperature controller out of the question

The display temperature is lower than the actual, too high temperature will cause PVC decomposition, yellowing. In this case, you need to re-check the temperature controller. The method is very simple, using a mercury thermometer for comparison. In actual production, due to loose thermocouples, sticky materials and other reasons, will cause the temperature controller display temperature and the actual gap. In addition, it is recommended to use a high quality temperature controller.

Small bubbles in the sheet:

Causes of generation:

1.Too much moisture in PVC raw materials: such as in the summer rainy days, the raw materials are damp, that is, the water may not be fully discharged in the barrel of the machine, heat expansion, and then the formation of bubbles in the sheet.

2.In addition additives may also contain too much moisture.

In summary, the solution can be used: appropriate to extend the mixing time of the hot mixer, and the use of cooling mixer. This can effectively remove the moisture of raw materials.

3.The number of crystals in the sheet exceeds the standard, also known as fish eyes

The common cause of crystalline point is: some PVC resin particles are not plasticized, or plasticized poorly. The reasons for this are: bad quality of PVC resin itself. Under the condition of not replacing the PVC resin, the solution measures are:

First, appropriate to extend the mixing time and increase the mixing temperature to promote the absorption of additives. And the use of high-quality mixing unit, mixing unit on the material preplasticization effect, is irreplaceable.

Second, the mixed raw materials can be placed for half a day or a day, let it ripen, and then use.

Third, you can appropriately increase the barrel setting temperature, increase the screw speed, increase the head pressure and other aspects to further improve the plasticizing performance.

Fourth, in the formulation, we must carefully select the appropriate additives, and the amount of additives, the current additives market is more confusing, product quality varies greatly, to carefully select, find a better balance between price and performance.

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