Automatic Paper Honeycomb Making Machine The Better The Heat Sealing Performance, The More Stable The Quality Control

Heat sealing temperature

The choice of thermal sealing temperature of composite film is closely related to the performance and thickness of composite base material, the model, speed and heat sealing pressure of the Automatic Paper Honeycomb Making Machine, which directly influences the high and low strength of the heat seal.

The sealing temperature of the composite film is the viscous flow temperature of the heat sealing material tf (or molten temperature tm) decides that the maximum temperature of the heat seal can not exceed the decomposition temperature of the heat sealing material ta. The temperature range between Tf (Tm) ~ta is the heat sealing temperature range of the heat sealing material. It is the key factor that affects the quality control of heat seal, the wider the temperature range of heat sealing, the better the heat sealing performance, the easier the quality control and the more stable.

At the same time, the thermal sealing temperature of the composite film can not be higher than the heat setting temperature of the printed material. Otherwise, it will cause the shrinkage and wrinkling of the hot sealing parts, and reduce the thermal seal strength and the impact resistance of the bag. The heat resistance of the printed material is good, such as pet, ony, etc., in the production can improve the heat sealing temperature to rapid production, printing material temperature resistance, such as Bopp, the use of low heat sealing temperature, and by increasing pressure, reduce speed or choose low-temperature heat sealing material to ensure the strength of heat seal.

The heat sealing temperature should be set in the heat sealing temperature range, generally in the viscous-flow temperature tf (or melting temperature tm) on the 15℃~30℃ (if in this range, can not make the sealing layer really sealed, must be from the pressure, speed, mechanical properties to improve, the pressure is not greater the better, too big will damage welding edge, Cause the problem of root cutting. "Supplementary discussion"), hot sealing temperature is too high, easy to make hot sealing parts of the hot sealing material melt extrusion, reduce the heat seal thickness, increase the thickness and uneven welding edge. Although the intensity of apparent thermal seal is higher, it can cause the damage of root-cutting, and greatly reduce the impact resistance of the sealing (easy to produce the problem of broken bags, "add"), sealing performance. (This analysis makes sense.) ) The heat sealing temperature is lower than the softening point of the hot sealing material, and the heat seal layer can not be really sealed by increasing the pressure and prolonging the heat sealing time.

The temperature setting of the continuous automatic filling equipment is often high, because it is easy to be affected by the contamination, extrusion and cooling speed of the inner loading when hot sealing.

II. Heat sealing pressure

At the heat sealing temperature, the heat sealing material begins to melt, on the bonding surface pressure, so that the corresponding hot sealing materials contact, infiltration, diffusion, but also promote the film surface of the gas escaping, so that the surface of the heat-sealing material to reduce the distance between the molecules, resulting in a larger intermolecular force, thus increasing the thermal seal strength. (Additional heat seal theory)

The heat sealing pressure is provided by the spring on the bag-making machine. For lightweight packaging bags, the heat sealing pressure is at least 1. 96n/㎝² above. The size of the heat seal pressure is related to the structure, thickness, and heat seal width of the composite film.

The heat sealing material has higher activation energy, and the effect of temperature increasing on the viscosity decreases, and the heat sealing pressure is less, so as to avoid the hot sealing material being extruded, the heat sealing effect is reduced. and PE, pp for non-polar heat sealing material, activation energy is very small, the required pressure is higher, on the thermal seal strength, interfacial heat seal is advantageous. (This section, how to understand, should be heat sealing material with higher activation energy and lower activation energy heat sealing material, PE, PP is commonly used hot sealing material, here refers to the ordinary model of PE, pp materials, is a small activation energy of the heat sealing material, and with the copolymerization, blending modification, or special catalysis, Ionic resin and other hot sealing materials, such as MPE, EVA, EAA, Emaa, Surlyn, etc. are the activation energy of the hot sealing material. I don't know, right? )

The heat sealing pressure increases with the thickness of the composite film, if the heat sealing pressure is not enough, the hot sealing layer film is difficult to heat, it is difficult to arrange the bubble in the middle of the weld, the heat sealing pressure is too high, will squeeze the molten material, damage welding edge, cause the root. When calculating the heat seal pressure, consider the width of the desired hot-sealing rod (refers to the width of the heat seal rather than the entire width of the rod) and the actual surface area (refers to the thermal seal contact area). The wider the width of the Heat seal bar, the greater the pressure required. Hot sealing rod width is too wide, easy to make hot sealing parts entrainment bubbles, difficult to heat seal firmly. Generally using hollow hot sealing rods, in the last one to strengthen the thermal seal fastness. The same width (heat seal width) of the hot sealing rod, if the surface, the actual contact area is greatly reduced, the unit area pressure increases correspondingly. This is useful for packing bags with large heat seal widths.

III. Heat SEALING speed

The heat sealing speed embodies the production efficiency of the Automatic Paper Honeycomb Making Machine, which is also an important factor affecting the strength and appearance of the Heat seal. The faster the heat seal, the heat seal temperature should be raised correspondingly to ensure that the heat seal strength and heat seal state reach the optimum value; under the same heat sealing temperature and pressure, the slower the main degree of heat seal, the more solid the fusion of heat sealing material will be, but it can not cause root-cutting phenomenon.

In the domestic bag-making machine, the length of heat sealing time is mainly determined by the speed of the Automatic Paper Honeycomb Making Machine. To increase the heat sealing time, it is necessary to reduce the bag making speed and reduce the hand productivity. If the use of independent inverter motor control hot sealing rod lifting and feeding, independent adjustment of heat sealing time, without changing the bag speed, it is greatly convenient for the operation of Automatic Paper Honeycomb Making Machine and quality control. (Domestic has several manufacturers can produce this bag-making machine, using three inverter motor, an independent control of heat seal time.) At present, the purchase of the Smick 600-type bag machine belongs to this, not the above-mentioned domestic bag-making machine to control the production of heat seal time to be determined by the speed. )

IV. Cooling CONDITIONS

The cooling process is under a certain pressure, with a lower temperature on the fusion of the weld just sealed, to eliminate stress concentration, reduce the shrinkage of the weld, improve the appearance of the bag, improve the process of heat seal strength. The cooling water of the Automatic Paper Honeycomb Making Machine is usually running water or about 20 ℃. If the water temperature is too high, the cooling rod pressure is not enough, the cooling water circulation is not enough, the circulation is not sufficient to lead to poor cooling, heat seal strength love to influence.