Example 67PC transparent rigid sheet
DATE：2019/12/25 9:08:18 / READ： / SOURCE：This station
Example 67PC transparent rigid sheet
1. Material selection and formula design
(1) PVC resin is made of non-toxic and loose resin, and requires high whiteness, suitable viscosity, easy plasticization, good thermal stability, short gelation time, uniform particle size, and narrow relative molecular mass distribution. Select the national standard SG-7 type PVC, viscosity (1.50 ～ 1.60)
x10-3Pa ・ s, K value is about 60, polymerization degree is 700, vinyl chloride monomer content is less than 5
2) Stabilizers are produced by extrusion-feeding and calendering methods to produce PVC non-plasticized hard sheets for blister molding. Due to the short process flow and high molding temperature, the melt is plasticized on the barrel and the shear is subjected to shear delay The pressure is high, so the selection and use of stabilizers is particularly important. In addition to considering sanitation, compatibility, stability and transparency, the influence of PNC melt fluidity must also be taken into consideration, and Beijing Tin TVS-8831 and Organic Tin TM-181FS produced in the United States with the above comprehensive effects must be selected. In order to reduce the cost and reduce the amount of the main organotin stabilizer, a small amount of epoxy soybean oil, monophenyl diisooctyl phosphite (PDOP), calcium stearate, and zinc stearate can be used as auxiliary stabilizers. Anti-oxidation and anti-UV degradation
(3) When the lubricant is extruded and fed into the transparent PVC rigid sheet, the melt of the PVC is
The barrel and calender rolls of the extruder are subject to high pressure, especially in the head. This high pressure causes a large friction between the PVC melt and the surface of the screw, barrel, head cavity, die lip, and calender roll in the staggered area, resulting in higher shear stress, which leads to extrusion pressure and melt through calender Due to a series of problems such as uneven distribution of shear force and unstable production during the silver settlement, the lubricity of materials is very important. It has been proved by production practice that in addition to considering the gelation behavior and melt flow of the material, the formula design must also consider the range of shear rate, and reasonably consider the relationship between flow efficiency, anti-sticking and plasticizing time. While determining the correct relationship between internal and external lubrication, we must also pay attention to the lubrication balance before, during and after the processing. This example mainly uses glycerin partial fatty acid esters, such as ZB-16, ZB8-74, H-74, and stearic acid as lubricants:
According to processing conditions, calcium stearate, zinc stearate, 705, Hg16, white oil, etc. are also selected for lubrication
Agent to prevent material from sticking to equipment. The transparency of PVC can also be used as a standard for measuring the internal and external lubrication efficiency of lubricants.
(4) Poor modifier processability and poor product toughness are major drawbacks of PVC. To make up
1. Material selection and formula design
(1) PVC resin is made of non-toxic and loose resin, and requires high whiteness, suitable viscosity, easy plasticization, good thermal stability, short gelation time, uniform particle size, and narrow relative molecular mass distribution. Select the national standard SG-7 type PVC, viscosity (1.50 ～ 1.60)
x10-3Pa ・ s, K value is about 60, polymerization degree is 700, vinyl chloride monomer content is less than 5
2) Stabilizers are produced by extrusion-feeding and calendering methods to produce PVC non-plasticized hard sheets for blister molding. Due to the short process flow and high molding temperature, the melt is plasticized on the barrel and the shear is subjected to shear delay The pressure is high, so the selection and use of stabilizers is particularly important. In addition to considering sanitation, compatibility, stability and transparency, the influence of PNC melt fluidity must also be taken into consideration, and Beijing Tin TVS-8831 and Organic Tin TM-181FS produced in the United States with the above comprehensive effects must be selected. In order to reduce the cost and reduce the amount of the main organotin stabilizer, a small amount of epoxy soybean oil, monophenyl diisooctyl phosphite (PDOP), calcium stearate, and zinc stearate can be used as auxiliary stabilizers. Anti-oxidation and anti-UV degradation
(3) When the lubricant is extruded and fed into the transparent PVC rigid sheet, the melt of the PVC is
The barrel and calender rolls of the extruder are subject to high pressure, especially in the head. This high pressure causes a large friction between the PVC melt and the surface of the screw, barrel, head cavity, die lip, and calender roll in the staggered area, resulting in higher shear stress, which leads to extrusion pressure and melt through calender Due to a series of problems such as uneven distribution of shear force and unstable production during the silver settlement, the lubricity of materials is very important. It has been proved by production practice that in addition to considering the gelation behavior and melt flow of the material, the formula design must also consider the range of shear rate, and reasonably consider the relationship between flow efficiency, anti-sticking and plasticizing time. While determining the correct relationship between internal and external lubrication, we must also pay attention to the lubrication balance before, during and after the processing. This example mainly uses glycerin partial fatty acid esters, such as ZB-16, ZB8-74, H-74, and stearic acid as lubricants:
According to processing conditions, calcium stearate, zinc stearate, 705, Hg16, white oil, etc. are also selected for lubrication
Agent to prevent material from sticking to equipment. The transparency of PVC can also be used as a standard for measuring the internal and external lubrication efficiency of lubricants.
(4) Poor modifier processability and poor product toughness are major drawbacks of PVC. To make up
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