In the extrusion production process of PVC foam board
, the influence of formula, technology, equipment, and other factors should be comprehensively considered.
Although there are various manifestations of quality defects of PVC foam board, in summary, they are all related to the improper grasp or unsatisfactory control of the above three key factors. Today, it is mainly discussed from the aspect of the balance between the maximum foaming rate of the melt and the cells. The followings are the balance links that affect the quality of the PVC foam board.
(1) The balance between foaming agent and regulator
The foaming agent and the foaming regulator are balanced, that is, by adjusting the ratio between the foaming regulator and the foaming agent, the foaming rate and the melt strength can reach the best balance point. So as to prevent the occurrence of foam breaking, string foaming, low product foaming rate, and high density.
(2) The balance between yellow foaming agent and white foaming agent
The yellow foaming agent is an exothermic foaming agent with large foaming volume, short foaming time, rapid foaming and strong suddenness. As an endothermic foaming agent, the white foaming agent can absorb the heat generated during the foaming process of the yellow foaming agent, cool the former, release gas stably and evenly, increase its own foaming rate, and inhibit overheating and degradation of thick plates.
In addition to the regulator, the balance between the yellow foaming agent and the white foaming agent should be adjusted during the production process. Usually, the white foaming agent should be added appropriately without affecting the foaming rate to help reduce the foaming state and control the difficulty and obtain a more suitable cell structure.
(3) The balance between the external lubricant and internal lubricant
The internal and external lubrication balance is a key element in the production of plastic products, and it is also the same in the production of PVC foam board. The so-called external lubricant agent refers to the non-polar substance that is incompatible with the resin, which adheres to the surface of the resin after melting, reduces the frictional heat between the melt and the processing equipment, and delays the plasticization of the melt.
The internal lubricant agent refers to an auxiliary agent that can be melted with PVC resin, can fully penetrate into the molecule after melting, reduce friction and force between molecules, improve the material or melt dispersion, and promote melt plasticization and balanced flow.
Due to the different effects of internal and external lubricant agents in the processing process, this requires us to try our best to find the balance point of the internal and external lubricant agent components in the formulation design, so that the melt has good plasticization and mold release properties, and has a relatively high degree of plasticization.
(4) The balance between plasticization and degradation of materials
In view of the fact that the plasticization temperature and degradation temperature of PVC are relatively close, in actual operation, on the one hand, it is necessary to provide sufficient temperature and shear force to the product to ensure that it is plasticized in the optimal foaming temperature region; at the same time, it is necessary to add an appropriate amount of stability to the formula It also uses extruder cooling measures to inhibit PVC degradation.
(5) The balance between the space provided by the shaped board and the volume of the foam
In order to maximize the foaming rate of PVC foam products without breaking the foam, in addition to controlling the balance between the foaming agent and the regulator, the shaped board must not only meet the requirements of melt foaming but also Make the foamed melt bear a certain pressure. As an expert in the research of PVC foam board for many years, Sounda can give you some professional suggestions on the manufacture of PVC foam board.
As a professional manufacturer of advertising, digital printing, and construction materials
, we always insist on providing customers with high-quality products. Sounda has become a leader in the industry by virtue of its excellent manufacturing technology and thoughtful service attitude. We always uphold a responsible attitude for users and strictly control the quality of our products. If you want to buy our PVC foam board, please contact us immediately!