Composite film bag, it is necessary to know this at 8 o 'clock!

Compound the most important function of packaging is to protect all the quality of the packaged goods, which requires the composite membrane in the process of bag making seal must have a certain strength and sealing performance, able to bear the pressure of a certain weight content, ensure the flow of goods in the process of composite bags not cracking, leakage, achieve the purpose of protect goods. The bag is to deliver user before a final production working procedure, quality control is more important. The choice of materials to non heat sealing material for the surface material, should consider to choose good heat resistance, thermal deformation of small material advisable, such as BOPA, BOPET, BOPP, paper, etc. Lining material namely, heat sealing material, in order to lower than the surface material thermal deformation temperature 30 ℃ to heat sealing advisable, if the surface of material and heat sealing layer of thermal deformation temperature difference is too small, will bring bag making temperature control is difficult, because the temperature is low, the sealing fastness is poor, can not meet the requirements, in order to improve the sealing fastness, temperature rise will be due to the thermal deformation temperature of inside and outside layer materials is too small, easy to burn surface materials. For the same kind of heat sealing material, the heat sealing strength increases as the heat sealing material thickness. So back sealing bag, self-reliance bag the lining material should be with more than 30 microns thickness advisable, if the inner material is too thin, will affect the sealing of the finished bag. Zipper should choose heat sealing zipper sealing strip temperature is low, general with lower than the lining materials can be heat sealing temperature 5 ~ 10 ℃ for beautiful, MWCNTS with lining material in order to achieve the best condition. Bag before preparation of 1, to ensure that the composite membrane composite layer solidify completely, otherwise easy cause after bag heat sealing edge deformation, affect the appearance of the bag; 2, selecting the appropriate heat seal as required, and clean up, make sure heat sealing knife with smooth surface, check whether the insulation cloth is in good condition, smooth; 3, check the bag making machine parts, according to the experience ( Refer to previous similar material production conditions) The preset pressure sealing temperature, preheating, 20 minutes to reach the preset temperature rear can start put into production. It doesn't mean the heat seal note reaches the preset temperature has reached the preset temperature, should be a process of heat conduction to achieve balance; 4, adjustment of bag making process conditions (temperature, pressure, time Speed) Three factors are indispensable for heat sealing, and is the main condition of the process parameters, temperature, pressure, time, Speed) Adjust to be watching out for each other to reach the best state. Heat sealing temperature heat sealing temperature effect on the heat sealing strength most directly, it is the main basis of choosing the best temperature viscous flow state. Heat sealing temperature should be according to the thickness of composite materials, and processing speed, etc. In the actual production process, due to heat sealing pressure, bag making speed and the thickness of the composite base material, the influence of such factors heat sealing temperature tend to be higher than the melting temperature of the heat sealing materials. If the heat sealing temperature below the melting temperature of the heat sealing materials, even if the increased pressure and to extend the time of heat sealing, can make the heat sealing layer real sealing; Jorge sealing temperature is too high, and easy damage pincer-like device heat sealing materials, greatly reduce the strength of the sealing. Sealing pressure under normal circumstances, the pressure is determined first adjust parameters, general equipment pressure value to heat sealing blade pressure side about 3 mm advisable, pressure balance, Around or before and after) Is very important, compressed little pressure is insufficient, make thermal cover is difficult to really fusion together, lead to local heat sealing not firm, sometimes also can produce phenomena of the bubbles out of weld are not clean. Compression is too large will cause too much pressure, will cause heat seal and traction are not synchronized, and in the heat sealing at high temperature, pincer-like device materials are already in molten state, if pressure is too large, easy to squeeze out some hot sealing material, the sealing edge half cut off state, cause pincer-like device materials thin, crisp, heat sealing strength reduced. The sealing time ( Speed) Sealing time not only affect the heat sealing strength but also affects the appearance of the composite bags flatness. In the fixed heat sealing temperature and heat sealing pressure, heat sealing, the longer the heat sealing layer fusion more fully, combined with the stronger, the sealing strength is higher, but if the heat sealing time is too long, thin film easy shrink, easy to cause pincer-like device wrinkling, influence smoothness appearance. By using low temperature cooling process is to finalize the design just after melting heat sealing weld. Cooling temperature should be at the lowest temperature condensate with cooling knife is not advisable, cooling water circulation flow, if no conditions when using the cooling water, the water flow rate should be increased, and to ensure that the cooling effect. If the sealing side of cooling after hot sealing is not enough, cause to finalize the design is insufficient, can't eliminate the internal stress, will affect the heat seal strength and appearance. Number of heat sealing heat sealing heat sealing strength is higher, the more general requirements heat sealing number for at least two more times. Longitudinal heat sealing number depends on the longitudinal heat sealing knife effective length and the ratio of the bag length; Lateral heat sealing number by the lateral heat sealing bag making machine unit number of group decision. Control of the process of the production process should continue to check the finished product quality, in addition to size, appearance visual inspection, but also for the sealing strength and sealing performance tests. Found problems in a timely manner to adjust, and make a detailed record. Three edge sealing zipper bag making, for example, should check the following items: 1, heat sealing strength; 2, the size of the bag, flatness, appearance quality, bag before and after the alignment and other customer specified requirements, such as tearing mouth position, etc. ; Zipper put way, especially in the zipper connection; 3, interior and exterior opening force of zipper, PE zipper opening force within the general requirements & ge; 50 n / 50 mm, PP zipper opening force within the general requirements & ge; 60 n / 50 mm;