Polyethylene tubular blown foaming film
DATE：2022/6/9 8:47:02 / READ： / SOURCE：This station
Polyethylene tubular blown foaming film
The tubular blow molded foam film (sheet) has an attractive appearance like mother of pearl, and can be used as a soft filling material with high temperature strength. The raw material of this product is mainly low-density polyethylene. Recently, a similar product has been made from high molecular weight polyethylene and can be used to replace opaque paper. Both chemical foaming and physical foaming can be used to form these tubular foaming films. The physical foaming method is mainly mechanical foaming. The cell of the tubular blown foaming film is closed cell foam. Lithium battery diaphragm equipment www.handern comThe final density of the tubular blown foaming film (sheet) is 300~400kg/m, which is independent of the foaming system. To achieve a lower density, it is necessary to increase the melt elasticity. Increasing melt elasticity can be achieved by mild crosslinking or by adding compatible thermoplastic elastomers. Adding thermoplastic elastomer can improve the inherent low tear strength of the material, but this method will bring the problem of yellowing. The key control parameters of this foaming product are still melt pressure and temperature. In addition, the design of hidden die and the selection of polymer should be considered. In practical application, the basic form of the die used is the bottom center feeding, high-pressure spiral die. This kind of die is easy to obtain uniform die soldering pressure.
1. raw material selection: lithium battery diaphragm equipment www.handern com
The selection of polymer is very important, and its indicators are mainly melt strength and elasticity. In order to maximize melt elasticity and make its composition fixed after cooling, it is necessary to select a polymer with low solder flow rate (MFR is 0.3~2.0g/10rmin). In the production of monolayers, the problem is that the gel shrinks, which will lead to the tearing of the film surface. The use of polymers with narrow molecular weight distribution will improve this problem. This is due to the migration of the low molecular weight part to the membrane surface or the degradation of the polymer.
Density of the tubular blown foam film is directly related to physical properties required for end use. Reducing the density by 20% will reduce the tear strength by 40%, unless EVA or rubber additive is used. Therefore, sometimes coextrusion method can be used to reduce raw material cost.
2. production process lithium battery diaphragm equipment www.handern com
Low density polyethylene (LDPE) foaming film production line can have two forms. ① One is a series extrusion unit, which can automatically mix and measure the low-density polyethylene particles and foaming additives, and then send them to the feeding port. The specific process is as follows.
The first stage extruder basically plasticizes the materials. At the head of the first stage extruder, the non combustible foaming gas (or foaming agent) is pressed into the extruder by a gas pump, and then sent to the intersection by the connecting pipe between the two extruders after mixing. Then through the screw transformer set at the intersection
The filter screen used for the exchanger is filtered and sent to the second stage extruder (i.e. the cooling extruder for stable extrusion). The second stage extruder stirs again, transports the resin with added foaming agent or gas, and carries out stable extrusion foaming molding and cooling shaping (similar to the horizontal film blowing method). After finalization, the membrane tubes are divided into upper and lower pieces by the blades on both sides and sent to the traction coiling part. The size of the formed film is 1.1~1.2m wide and 1~4mm thick. The film production speed is 3~30m/min, and the foaming ratio is 30~33 times. The combination of two series extruders is 65/90 or 90/120 (65 is the screw diameter of the first stage extruder and 90 is the screw diameter of the second stage extruder). The length diameter ratio of the first stage extruder is 321, and the length diameter ratio of the second stage extruder is 25:1. The traction power of the draft gear is 2.2kW. The power of the port winding machine with the diameter of the traction rubber roller is 1.5KW. The winding speed is 3-30/on and the force is n5 2n m, maximum winding diameter 800mm. 005mm: the LDE in this China shall be packed with cushioning materials.
In addition, as long as the screw and die of the above-mentioned stage are replaced, the production line of fourth degree B foam sheet can be produced. Another form of the production line is to use Xiao Yi wedding hair treatment tablets as shown in Figure 8-14. The main machine of the 63 Eagle type plastic device is an imported mixer extruder. The extrusion screw is of three-stage type, the length diameter ratio is greater than 24, and the compression ratio is (31~ (3.5 · 1). In order to ensure the plasticizing quality and constant die pressure, it is required that the length of the screw metering section is 10~12 screw diameter. The screw mandrel type mouth fan with bottom feeding as shown in Figure 63 can not only ensure sufficient die melt pressure, but also provide relatively uniform material flow. Lithium battery diaphragm equipment www.handern com
Author：admin