Some Knowledge Of "Plasticizing Degree" In The Production Of PVC Products
1.The influence of plasticizing degree on the performance of the product:
The performance of PVC products is closely related with the degree of plasticization, plasticizing degree, brittle hair products, mechanical properties can not meet the requirements; the plasticizing rate is too high, products will appear yellow line, the mechanical properties are not qualified, is very important in the process of plasticizing degree of PVC products in.
1)when the plasticizing degree is 60%, the tensile strength is the highest;
2)when the plasticizing degree is 65%, the impact strength is the highest;
3)when the degree of plasticization is 70%, the elongation at break is the highest;
For the production of water supply pipe material, plasticizing degree of 60-65% is the most appropriate. Because in this range, it can show two properties of tensile strength and impact strength.
2.Influence of temperature on ductility:
Polymer materials cannot be melt at lower than 80 DEG C, a glass, glass material that is hard and brittle, in glassy materials can not be processed; with the increase of temperature to 160 DEG C when the materials in the high elastic state, but in the area of material or not flow, can only make the material become soft, viscoelastic increase; and really can reach PVC, the melt processing flow, the temperature should be 160-200 degrees, but for any long- term heat stabilizer, at a temperature above 200 DEG C, and the material decomposition,Therefore, when controlling the plasticizing degree, the temperature can only be controlled between 160-200 degrees centigrade. In the temperature range of 40 DEG C, when the temperature of PVC is set at 170-180 DEG C, the plasticization is better.
3.Improve the degree of plasticizing method:
1)by increasing the temperature of the fuselage and screw.
2)when the screw speed is normal, the feeding rate of the feeder is increased to improve the plasticizing degree
3)in the extruder rated speed and meet the feeding conditions, improve the extruder speed.
The role of ripening period:
1)Eliminate static electricity and reduce pollution
2)increase the apparent density
3)increase plasticizing degree
4)low molecular polymerization, uniform dispersion, to prevent extrusion instability.
5)increase the partial plasticization by reducing the temperature of the confluence core.
4.how to determine the degree of plasticization:
1)through the host current to determine the degree of plasticization, (65/132 production line as an example, the host current to 46-52A is appropriate, if it is low calcium products, 45-50A is appropriate. The premise is that the screw speed is 16~22r/min, the feed is full and matched with the screw speed, the temperature setting is matched with the screw speed and the host current;
2)Observe the plasticizing degree of the material through the vacuum vent of the main engine (that is, the material is filled with more than 60% in the middle of the screw flange, and the powder in the spiral groove is bean curd slag and the material at the bottom of the groove is flattened);
3)Determine the plasticizing degree by the viscoelasticity of the melt material in the die;
4)the degree of plasticization is determined by the melt pressure and melt temperature of the confluence core. The disadvantages are that if the instrument fails or the core of the mixed sensor is burnt, the accuracy of the result will be affected.
Tongxiang long Cheng Plastic Co., Ltd. has nearly 20 years experience on PVC granule research,development and granulation production. Professional and technical service team can provide one-stop system solution for customers.
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