In the process of film production and processing, for various functional needs, color masterbatches of different colors are often added to the resin to produce films of different colors. During this process, some problems will be encountered. The following are common problems and solutions. 1. Grain on the surface of the product. Cause analysis: ①There are impurities in the barrel and die; ②The temperature is incorrect; ③The heating and residence time of the raw materials in the barrel is too long; ④ The dispersion of color masterbatch or toner has not been processed well; ⑤The filter screen has been perforated. Solution: Adjust the temperature of the molding machine to 10-20℃ lower than the normal temperature, start the molding machine, and use the original color plastic resin to clean up again at the slowest speed. If necessary, disassemble the die for cleaning, and adjust the temperature in time. Replace the filter. Use a well-dispersed masterbatch or toner to re-adjust. 2. Uneven diffusion Cause Analysis: ①Uneven mixing; ② Improper temperature; ③The color masterbatch has poor compatibility with raw materials; ④The plasticizing effect of the plastic machine itself is poor; ⑤The proportion of color masterbatch is too small. Solution: Stir fully, adjust the

    In the last introduction, we mainly discussed composite film, heat shrinkable film and stretch film. Let’s take a look at agricultural film today. China is a large agricultural country and there is a great demand for agricultural films. According to the purpose, it can be roughly divided into solar greenhouse film (including EVA), ordinary greenhouse film (PE), mulching film and other special functional films. 1. Solar greenhouse film     Solar greenhouse film is mainly used in winter to play a role in heat preservation. Usually one side is a thick wall, east-west direction, with good thermal insulation effect. The film faces south, allowing sunlight to penetrate during the day, and the temperature in the shed rises; at night, because EVA can well block the far infrared, the temperature in the shed is well maintained, and the crops will not freeze. The higher the VA content in EVA, the better the insulation effect. At the same time, due to the change in temperature, the water vapor in the shed will condense into water droplets on the surface of the film. In order to prevent the dripping of water from causing damage to crops and pests, it is necessary

Introduction of several basic blown film raw materialsRaw material characteristicsBasic performance: melt flow rate densityMechanical properties: Flexural strength, tensile strength at break, tensile strength at yield, environmental stress cracking resistance, impact strength, ultimate tensile strength, Rockwell hardnessThermal performance: melting point, Vicat softening point, embrittlement temperature. 1. Polyethylene (PE)(1) Performance and use    Polyethylene is a typical thermoplastic, a flammable white powder that is odorless, tasteless and non-toxic. The polyethylene resins used for molding are waxy pellets that have been extruded and pelletized, and their appearance is milky white. The molecular weight of polyethylene is between 10,000 and 1 million, and those with a molecular weight of more than 1 million are ultra-high molecular weight polyethylene. The higher the molecular weight, the better its physical and mechanical properties, but as the molecular weight increases, the processing performance decreases. Therefore, the appropriate molecular weight and processing conditions should be selected according to the use situation. High molecular weight polyethylene is a processing structural material and load material, while low molecular weight polyethylene is only suitable for coating, polishing agent, lubricant and softener. The mechanical properties of polyethylene depend to a large extent on the molecular weight, degree of branching and crystallinity of

    During the extrusion process of the extruder, the molten material is conveyed to the die through the filter screen. The filter screen allows the material to be filtered and can improve the mixing effect of the material. However, the filter screen can also cause fluctuations in the process, leading to an increase in back pressure and temperature of the molten material, and sometimes a decrease.    The filter screen of the extruder is fixed on a porous or grooved protective plate, which can form a seal between the extruder and the die. The pressure generated by a clean filter is relatively small, which may only be 50-100lb/in2 (1lb=0.4536Kg, 1in=25.4mm). As the pressure increases, the amount of impurities in the resin trapped on the filter net increases, thereby clogging the filter net. The filter screen will affect the temperature of the molten material. When a blocked filter screen is replaced, the pressure will suddenly drop, and the temperature of the molten material may also drop, resulting in a change in the size of the product. In order to maintain the same size of the product, the screw speed of the extruder can be adjusted, and the linear speed of

1. Polyethylene material    Polyethylene is the simplest polymer and the most widely used polymer material. It is made up of repeated -CH2- units connected together. Polyethylene is formed by the addition polymerization of ethylene (CH2=CH2). The performance of polyethylene depends on its polymerization method. High-density polyethylene (HDPE) is produced by Ziegler-Natta polymerization under medium pressure (15-30 atmospheres) and organic compound catalyzed conditions. Under this condition, the polymerized polyethylene molecule is linear, and the molecular chain is very long, and the molecular weight is as high as hundreds of thousands. If it is under high pressure (100-300MPa), high temperature (190-210°C), and peroxide catalyzed by free radical polymerization, low density polyethylene (LDPE) is produced, which has a branched structure.     Polymerization pressure: high pressure, medium pressure, low pressure; polymerization implementation methods: slurry method, solution method, gas phase method; product density: high density, medium density, low density, linear low density; product molecular weight: low molecular weight, ordinary molecular weight , Ultra-high molecular weight. Polyethylene characteristics: Polyethylene is odorless, non-toxic, feels like wax, has excellent low temperature resistance (the minimum use temperature can reach -70～-100℃), has good chemical stability, and can withstand most acids and alkalis (not resistant) Acid with oxidizing properties), insoluble

    Polypropylene (PP) has a high melting point and excellent comprehensive properties. It is one of the most promising thermoplastic polymer materials today. Compared with other general thermoplastics, it has low price, small specific gravity, yield strength, tensile strength and surface It has excellent mechanical properties such as strength, outstanding stress crack resistance and wear resistance, good chemical stability, easy molding and processing, and a wide range of applications. It has been widely used in chemicals, electrical appliances, automobiles, construction, packaging, etc. industry. At present, most of the packaging market from food to groceries uses plastic film instead of paper as a flexible packaging material. The plastic film used for commodity flexible packaging must meet the requirements of protection, workability, convenience and economy of commodity packaging materials, have suitable strength, have barrier properties, stability, safety, beauty and transparency, and economic convenience Sex.     According to different processing techniques, polypropylene film can be divided into CPP film, BOPP film and IPP film. The relevant conditions are as follows:   CPP film and characteristics     CPP films and polypropylene films produced by the casting process. CPP films can be divided into general-purpose, metallized and retort films. The general type

    If you determine that there is a film blowing project, the next step is to plan the equipment you need.     The film blowing machine is a machine that heats and melts the plastic particles and then blows them into a film. It consists of an extruder, a film blowing die, an air ring, a tractor, and a winder. Each part has its own special requirements, let’s explain each part. Extruder of film blowing machine.     Blown film is inseparable from plastic extruders. The first question that many people pay attention to when purchasing an extruder is how much is the price? I always think this view is incorrect. In fact, the first is quality and performance, and the second is price. Don’t just look at the shape of an extruder. In fact, the internal design is the most important thing.    A reasonably designed barrel screw needs to meet the following conditions:1. Good plasticization,2. Fast discharging,3. Low energy consumption,4. Good brightness,5. Low friction temperature,6. Good heat dissipation performance,7. Running smoothly.    If you already have an extruder, you might as well check it. Does your existing equipment have these advantages? Once the purchased equipment lacks

1. The current of the film blowing machine is unstable1. Reasons for production:(1) Uneven feeding.(2) The main motor bearing is damaged or poorly lubricated.(3) A certain section of the heater fails and does not heat.(4) The screw adjustment pad is wrong, or the phase is wrong, and the components interfere.2. Treatment method:(1) Check the feeder and troubleshoot.(2) Overhaul the main motor and replace the bearings if necessary.(3) Check whether the heaters are working normally, and replace the heaters if necessary.(4) Check the adjustment pad and pull out the screw to check whether there is interference in the screw. 2. The main motor of the film blowing machine cannot be started1. Reasons:(1) The driving procedure is wrong.(2) There is a problem with the main motor thread, and whether the fuse is burned.(3) The interlocking device related to the main motor works2. Treatment method:(1) Check the procedure and restart the car in the correct driving sequence.(2) Check the main motor circuit.(3) Check whether the lubricating oil pump is started, and check the status of the interlocking device related to the main motor. The oil pump cannot be turned on, and the motor cannot be turned on.(4) The inverter’s induction current has not

The following are important principles to keep in mind about crowding out. These principles can help you save money, produce high-quality film products, and use equipment more efficiently. 1. Principles of extruder machinery The basic mechanism of extrusion is very simple-a screw rotates in the barrel and pushes the plastic forward. The screw is actually an inclined surface or slope, wound on the center layer. The purpose is to increase the pressure in order to overcome the larger resistance. As far as an extruder is concerned, there are three types of resistance to overcome: the friction of solid particles (feeding) against the barrel wall and the mutual friction between them during the first few revolutions of the screw (feeding zone); melt The adhesion on the wall of the cylinder; the flow resistance inside the melt when it is pushed forward. Newton once explained that if an object does not move in a given direction, then the force on the object is balanced in this direction. The screw does not move in the axial direction, although it may rapidly rotate laterally around the circumference. Therefore, the axial force on the screw is balanced, and if it exerts a large forward thrust

    The processing process of the plastic granulator is basically: raw material classification → raw material crushing and cleaning → automatic feeding into the main machine for plasticization → auxiliary machine extrusion → water or air cooling → automatic pelletizing → bagging. The main components of the plastic granulator include: crusher, washing machine, dehydrator, dryer, extruder, pelletizer, etc. Today, Shanghai Duxia Industry and Trade Co., Ltd. will briefly introduce the common problems and solutions in the pelletizing process. 1. Continuous granulation problem of plastic granulator    Concatenated particles refer to the situation where a series of particles are connected to each other, that is, in some cases, the particles are connected to each other through the end of the film or in a tangential manner. During the processing, several process problems may cause this phenomenon alone or together. Too hot processing water is one cause of contiguous particles. In this case, the water temperature should be lowered to give enough quenching to the surface of the particles. Too low water flow rate is also a cause of continuous granulation, which will cause the particle cutting chamber to slow down and particle agglomeration. If the holes of the die are