Polyethylene bottle and PVC bottle
DATE：2022/12/6 8:55:46 / READ： / SOURCE：This station
Polyethylene bottle and PVC bottle
Polyethylene bottlePolyethylene bottle refers to all kinds of plastic intermediate products with a volume of only tens of milliliters to several liters. When the plastic bottle is molded by extrusion blow molding, the equipment and production process parts used are basically similar to the equipment and process conditions used for extrusion blow molding of polyethylene barrel, and the inner cavity shape is different.
Linear low-density polyethylene with a melt flow rate (MFR) of 0.5~2g/10min or high-density polyethylene with a melt flow rate (MFR) of 0.35~1.2g/10min can be used for polyethylene bottles. For example, DND-3040, DND-7342, DXND-1223 LLDPE resins produced by Sinopec Qilu Plastic Factory and 6200B HDPE resins produced by Sinopec Beijing Yanshan Petrochemical Co., Ltd. can be used to extrude blow molding bottles.
The quality requirements of polyethylene plastic bottles are basically the same as those of other types of plastic bottles. The specific quality requirements are as follows: see Table 11-4 for the bottle appearance quality requirements; See Table 11-5 for the height deviation of bottle; The mechanical properties of the bottle shall meet the requirements in Table 11-6; The deviation of the perpendicularity of the bottle (that is, the perpendicularity of the center line of the bottle to the bottom plane of the bottle) shall comply with the provisions in Table 11-7. If the bottle is used to contain food products, the average content of acetaldehyde in the raw materials for bottle making should be less than or equal to 3.0, and the maximum should not exceed 4.0. The hygiene indicators should meet the requirements of the standard GB 9687-88.
(1) SG5 or SG6 type suspension PVC resin shall be selected as raw materials. At present, PVC resin for extrusion blow molding PVC bottles is produced by several manufacturers. For example, EB101-1, EB101-3, EB102-1, EB105-3 produced by Shanghai Chlor Alkali Group Chemical Plant and K61, K63 and other resins produced by Fuzhou Erhua Group. See Table 4-11 for material formula.
(2) General single screw extruder is selected for equipment conditions. The screw structure is of equidistant gradual change type, the length diameter ratio is L/D ≥ 20:1, and the compression ratio is 4; Add perforated plate and filter screen in front of the barrel; The hopper seat and screw shall be cooled by water. The parison mould is of the structure shown in Figure 11-6. Refer to Table 11-2 to select special equipment for extruding hollow products according to bottle capacity.
(3) Forming process
① Production process sequence
Raw materials are measured separately according to the requirements of the formula → high-speed mixer mixes raw materials and mixes them evenly → granulation → extruder plasticizes raw materials to form blank tubes → blank tubes are blown in the forming mould → mold opening after cooling and shaping → product demoulding and trimming → finished products
② Raw materials shall be mixed and granulated according to Chapter 4.
③ The process temperature of plasticizing raw materials and forming blank tubes of the extruder (from the feeding section of the barrel to the homogenizing section): 145~150 ℃, 150~160 ℃, 165~170 ℃.
The temperature of blank tube forming die: 165~170 ℃.
The air pressure for the products formed by expanding the blank tube: 0.3~0.45MPa.
Author：admin