PVC has a wide range of applications due to its stable chemical properties, corrosion resistance, and high heat resistance. According to the amount of plasticizer used, there are two types of PVC: flexible PVC and rigid PVC. Due to various factors, bubbles and yellowing of the sheet may occur during the PVC Sheet production process. There are causes and corresponding solutions.

1. Yellowing of the product

The yellowing of the sheet may caused by poorly stabilization of the PVC raw material, in which case it needs to be replaced with a PVC material of acceptable quality. If the stabilizer is not enough, the amount of stabilizer needs to be increased.

Problems with the thermostat can also cause the temperature to be lower than it actually is, and too high a temperature can cause the PVC to decompose and yellow. In this case the thermostat needs to be re-checked for accuracy. This can be done with a mercury thermometer. In production, due to loosen thermocouples, sticky materials and other reasons, will cause the temperature controller display temperature and the actual gap.

2. Small air bubbles in the sheet

It may be that there is too much moisture in the PVC raw material: for example, the raw material is damp, the moisture cannot be fully discharged in the barrel of the machine, it is heated and expands, and then bubbles are formed in the sheet. The PVC Transparent Sheet Extrusion process needs to be adjusted, to extend the mixing time, to adopt a high and low speed mixing and stirring method, and to reduce the water content, the discharge temperature can be raised appropriately to evaporate the excess water.

3. Excessive crystalline spots in PVC sheets

The excessive number of crystalline spots is caused by the failure of the resin particles to plasticize, Most of the crystalline spots are caused by the failure of the resin particles to plasticize, attempts can be made to extend the mixing time of the mixture to make the additives used more evenly distributed. Many products have a fixed processing formula and special additives. The proportion of each raw material in the formula and the performance of the additives have a great deal to do with the plasticity of the product. In the process, it is important to select the corresponding raw materials, equipment and formula proportions according to the specific situation.

PVC transparent sheet is mostly produced by twin-screw extruders. In order to improve the plasticizing properties of the material and reduce the incidence of various problems, adjustments can be made to the production equipment. Kunshan Oneplus Machinery Co., Ltd. is a professional manufacturer of plastic machinery and equipment in China. WONPLUS plastic extruder has high output, stable quality and considerate service.