PVC transparent soft sheet
DATE：2021/9/16 8:40:18 / READ： / SOURCE：This station
PVC transparent soft sheet
1. Material selection and formula design
(1) Selection of raw materials
(1) PVC resin. The loose resin produced by the suspension method is mainly selected, and the tree whose absolute viscosity is in the range of 1.81～2.0s is selected according to the different strength requirements of the user for the sheet. 2) Plasticizer. Since this production process is to produce transparent film, in addition to the influence of plasticizer on the physical and mechanical properties of the film, it is also necessary to consider the compatibility, migration, durability and light and thermal stability of the plasticizer; Food hygiene requirements also need to consider the toxicity of plasticizers. Therefore, DOP, DOA, BBP, DOS, ESO, etc. are mainly used as film plasticizers.
(3) Stabilizer. There are higher requirements for the selection of stabilizers. In addition to considering the static stability compatibility and transparency of the stabilizer, more consideration should be given to the dynamic stability of the stabilizer. For those with hygiene requirements, the toxicity of stabilizers must be considered. This production process selects different types of stabilizers according to the different use requirements of the users for the film, such as TUS8 of Japan Chemical Industry, TM-181-FS of the United States, domestic Cd/Ba liquid stabilizer, CZ liquid stabilizer, C2, Cat, ZnSt, BaSt, etc. And choose ESO, PDOP as auxiliary stabilizer.
(4) Lubricant. Divided into internal lubricant and external lubricant. For PC film, the use of a large amount of plasticizer greatly reduces the viscosity of the PC melt, so the lubricant in the formulation should be mainly based on other lubricants. In addition to the compatibility, transparency, and lubrication efficiency of the lubricant, the choice of lubricant must also pay attention to the lubrication balance and the balance of internal and external lubricants in the early, middle and late stages of the processing process. This production process mainly selects HS, H-74, H-90OP wax, PE wax, oxidized PE wax, stearic acid amide stearyl alcohol, benzyl silicone oil, etc.
(5) Complementary color agent. In order to prevent the film from yellowing, a small amount of coloring agent should be added to the formula to achieve the purpose of color reduction. Generally, a small amount of transparent blue, transparent green, permanent violet, disperse violet, etc. are used as color supplements.
(2) Formula design
The formulation design is mainly based on the end use of the PVC film, combined with the equipment and technology of the extruded film. It should not only meet the performance requirements of the film, but also facilitate the control of the molding process. At the same time, it should minimize the cost and improve the economy of the enterprise. benefit. Since the plasticization performance of the extrusion process mainly depends on the twin-screw extruder, relatively speaking, its plasticization cycle is short. To ensure a good degree of plasticization of the film, the processing temperature and shear strength must be increased. Stable performance puts forward higher requirements; at the same time, the relevant properties of NC transparent film must be controlled by ingredients, such as tensile strength, elongation, hardness, low temperature performance, transparency, toxicity, etc.
Author：admin