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Process Problems And Solutions Of Extrusion Production Of PVC Transparent Sheet

Aug 15, 2017

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We often use pvc plate when they encounter a variety of problems, what are the problems encountered? Summarized as follows:

1. The color is yellow.

The causes and solutions are:

First, PVC itself is stable.

Second, the lack of stabilizer, or stabilizer quality problems

Third, the temperature controller out of the problem, showing the temperature is lower than the actual, the temperature is too high will cause PVC decomposition, yellow. Then need to re-check the more accurate temperature controller. The method is very simple, with mercury thermometer for more accurate. In the actual production, due to the thermocouple loosening, bonding materials and other reasons, will cause the temperature controller shows the temperature and the actual gap. Also recommended the use of high-quality temperature controller.

2. The sheet has small bubbles

Causes:

1. PVC raw materials in the water too much, such as in the summer rainy days, raw materials damp, that is, the water can not be fully discharged in the barrel, heat expansion, and then the formation of bubbles in the sheet.

2. Other additives may also contain high water content.

In summary, the solution can be used: the appropriate extension of the mixing time of the hot mix machine, the mixing temperature is generally maintained at 105-110 degrees, and the use of cooling mixer, cold mixing temperature is generally 45 degrees and below appropriate. That can effectively remove the raw material of water.

3. The number of crystal points in the sheet exceeded, also known as fish eyes.

The common causes of crystal point production are: some PVC resin particles are not plasticized, or plasticized is not good. The reasons for the formation are: PVC resin itself is not good quality or use too much 5 resin powder. Without changing the conditions of PVC resin, the solution is:

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

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

Third, you can appropriately improve the cylinder set temperature, increase the screw speed, increase the head pressure, etc., to further improve the plasticizing performance.

Fourth, in the formula, we must carefully choose the right additives, and the amount of additives, the current additives market is more chaotic, product quality is very different, to seriously choose, in the price and performance to find a better balance .

Summary, to consider the above reasons, choose the best solution. Some solutions to the existence of contradictory relations, such as raising the temperature may cause the sheet yellow, more stabilizers may cause costs and so on. Only in practice to explore the way forward.


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