Wuhan Handern Thermoforming Polypropylene Sheet
DATE：2020/5/18 8:39:49 / READ： / SOURCE：This station
Wuhan Handern Thermoforming Polypropylene Sheet
The most common sheet for thermoforming in Wuhan Handern is the polyvinyl chloride sheet. However, due to the poor hygienic performance and poor environmental protection of the polyvinyl chloride sheet, the polypropylene sheet has good hygienic performance, small density, and can be used at higher temperatures It is used and has high mechanical properties and chemical stability. Thermoforming it into a container is an ideal food and medical packaging material. There is a trend to replace PVC at home and abroad. However, polypropylene is a knotty polymer, and there are certain difficulties in molding. Therefore, it is easy to solve from the aspects of modified polypropylene material and improved packaging machinery. It has been used in production. The thickness of the sheet for thermoforming is between the thick film and the sheet, and the forming method uses an extruded CP sheet. The following is an example of modified polypropylene blister sheet used in blister packaging. www.handern.com Laminating equipment
1. Performance of modified polypropylene thermoforming sheet
1) General polypropylene is a crystalline polymer. Before the product is melted, there are almost no areas with high elasticity. The strength of the sheet is high, and the plastic molding is difficult. After the crystal is melted, the melt strength of the sheet suddenly decreases. It is difficult to use ordinary polypropylene sheet to meet the requirements of plastic molding. There are special polypropylene resin grades of plastic molding sheets abroad, such as F3020 and F3021 of Japan Muroishi Chemical Company. China's Liaoning Chemical Fiber Industry Company also has polypropylene resins suitable for high-speed deep-drawing films, with a brand of 4036, an MFR value of 7g10mi, and contains antistatic agents. www.handern.com Laminating equipment
The above-mentioned difficulties can be solved by blending and modifying high-density ethylene resin and general polypropylene resin. Polypropylene and high-density polyethylene do not form crystals when blended, but polypropylene and high-density polyethylene crystallize separately. When the temperature increases, the crystallization of high-density polyethylene begins to melt first, and then the temperature continues to rise, and the crystallization of polypropylene begins to melt. Since the high-density polyethylene and polypropylene are melted separately, the blending flow curve melting range Wider. The film's elongation and tensile strength reflect the temperature change later than that of pure polypropylene during blister, so the temperature control requirements for blister molding are not high and the operation performance is good. www.handern.com Laminating equipment
2) Raw materials and proportioning, polypropylene melt flow rate is between 0.5-4.0g / 10min. The high density polyethylene melt flow rate is between 0.1-2.0g / 10min. The ratio of polypropylene to high-density polyethylene resin depends on the raw material, and is between 8: 264. Generally speaking, the relative molecular mass of high-density polyethylene is large, the modification effect is obvious, the amount of access can be less, and the amount of rubbing in should be more. The melt flow rates of the two matched resins should be similar. www.handern.com Laminating equipment
3) Production example
① Equipment. Extruder: screw diameter 120m, length-to-diameter ratio 28, filter mesh 40 mesh 80 mesh / 40 mesh triple single layer, manifold T-shaped head, die width 1200mm, smooth roller diameter 4300, its internal water cooling or heating.
②Raw materials. The high-density polyethylene is produced by Yangzi Petrochemical Industry Corporation's olefin plant 50005. Polypropylene is produced by American Finna Petrochemical Company 3422. The ratio of polypropylene to high density polyethylene resin is 7: 3. www.handern.com Laminating equipment
③ The production process is T-shaped head extrusion process. www.handern.com Laminating equipment
④ Production process conditions: body temperature: 150 ℃ for the first stage, 160 ℃ for the second stage, 170 ℃ for the third stage, 180 ℃ for the fourth stage, 190 ℃ for the fifth stage, and 200 ℃ for the sixth stage. The temperature of the neck coupling is 200 ° C, and the head temperature (from left to right) is 210 ° C, 201 ° C, 200 ° C, and 205 ° C and 210 ° C. The temperature of the glazing roller is 50 ℃, the temperature of the glazing roller is 70 ℃, the temperature of the lower glazing roller is 60 ℃; the screw speed is 30r / min and the speed of the glazing roller is 4.5r / min. www.handern.com Laminating equipment
4) Diaphragm performance, taking 0.33m thickness as an example, tensile strength, longitudinal direction is 52.7MPa, transverse direction is 40. TMPa elongation at break is 400% in longitudinal direction, 280% in transverse direction; right angle tear strength is 269N / m , Horizontal direction is 135N / mme5) Modified sheet application, used for packaging of food, machinery, electronic devices, etc. Such as blister forming fast food box, tofu box, ice cream cup, jelly cup, aviation beverage cup, etc.
Author：admin