Blown Film Production Process Blow Molding Method Can Be Used to Produce Blown Film

HC Plastic mesh : Blown film production process and Faults Most thermoplastic blow molding method can be used to produce blown film, blown film is extruded thin plastic tube, then hot compressed air to blow plastic inflation, then by cooling tube obtained after setting products like films, directed this film's performance in the film between the same cast film: intensity than cast film is good, sealing of cast film worse than that. Film blowing production of many varieties, such as low density Polyethylene (LDPE), Polypropylene (PP) , High density polyethylene (HDPE), Nylon (PA), An ethylene vinyl acetate copolymer (EVA) and so here we are on the commonly used Low-density polyethylene (LDPE) film blow molding process and a simple description of common faults. Polyethylene blown film material selection 1. Selection of materials should be used blown film grade polyethylene resin particles containing the appropriate amount of slippery agent, to ensure the opening of film. 2. Resin particles melt index (MI) can not be too large, the melt index (MI) too, then the viscosity of molten resin is too small, narrow range of processing, processing conditions difficult to control, poor film-forming resin is not easy to process film; In addition, melt index (MI) too narrow polymer molecular weight distribution, strength of the film worse. Therefore, it should be used melt index (MI) is smaller, and relatively broad molecular weight distribution of resin raw materials, not only can meet the performance requirements of film, but also ensures that the resin processing characteristics. Blown polyethylene film generally used in the melt index (MI) in the range of 2 ~ 6g/10min between the polyethylene material. Blow molding process control points Blown film process is as follows: Hopper of a plastics Extrusion materials traction Inflation Wind Central cooling roller traction herringbone traction splint film winding corona treatment However, it is noted that the performance with the production of blown film process parameters have a great relationship, therefore, in the blown film process, the need to strengthen the control of process parameters, standardized production procedures, to ensure the smooth production for, and obtain high-quality film products. In polyethylene blown film production process, mainly to do the following control parameters: 1. Extruder Temperature Blowing low density polyethylene (LDPE) film, the extrusion Temperature is controlled between 160 ~ 170 , and must ensure that the nose temperature uniformity, extrusion temperature is too high, resin is easy to decompose, and the thin film brittle, in particular, the longitudinal tensile strength decreased significantly; temperature is too low, then the resin plasticizing poor, can not carry out smooth expansion of the tensile, tensile strength is low, and surface gloss and transparency, poor, even as the timber ring-like pattern and did not melt the nucleus (fish eyes). 2. Inflation ratio Inflation blown film production process than is the control of one of the points, after Inflation is the diameter of vesicles with and without Inflation tube diameter of the ratio between. Inflation higher than the horizontal expansion of multiples for the film, the film is actually a horizontal stretch, stretch plastic molecules would have a certain degree of orientation of the role of Inflation ratio increases, so that the transverse strength increased film. However, not much more than Inflation, otherwise easily lead to film bubble instability, and the film prone to wrinkles. Therefore, Inflation should be the same traction than the ratio with appropriate for the job in general, low-density polyethylene. Source: hicow.com