Packing bag heat sealing material knowledge, will look at this article

As hot sealing compound packing materials layer, because it is direct contact with the packaging, so, first of all, should consider its health, secondly also should consider its transparency, resistance to permeability, heat sealing and opening of the wicked. Now, the professional manufacturer of flexible packaging packaging details the five big film roots function and its application in field. A, polyethylene film ( PE） Feature used in composite heat sealing layer of polyethylene, first is the low density polyethylene and linear low density polyethylene ( Also some products choose medium density and high density polyethylene film do the heat sealing layer) Choose two kinds of polyethylene more generally, and each must share blend after use. According to the different processing method, can be divided into the blown film, stretch film and extrusion coating film. Compound with the thickness of the polyethylene film, on the basis of being packaging requirements, choose different thickness, thin, can be in 20 & mu; Left and right sides, thickness can be greater than 100 & mu; 。 Due to produce films with many additives in the resin, slip agent, in particular, should pay attention to when producing the relocation of additives. Applications of metallocene polyethylene is a modified polyethylene resin, made of metallocene polyethylene film, has good thermal adhesive strength, heat sealing strength, must seal pollution resistance function. Now the metallocene polyethylene with low density polyethylene blend membrane products, has been in the oil bag, shampoo bag, washing powder bag, etc widely used. Now the heat sealing layer of compound packing is largely made of polyethylene, such as convenient noodles, biscuits, preserved vegetable, pickles, etc. Blowing plastic film and stretch film in central processing process should pass edm processing, make the film surface tension is greater than 38 dyne/cm. Second, polypropylene film ( PP) Polypropylene film can be divided into blown film ( The blow water cooling method) , stretch film and extrusion coating film. In the polypropylene film, stretch film of polypropylene film ( The CPP film) Is to use one of the most frequently, it is first used in high temperature cooking packaging, high transparency requirements of packaging, made aluminum plating CPP (CPP film plating aluminum VmCPP) Later, in the puffed food packing, the packing and so on. High-temperature cooking CPP and aluminum plating with CPP material and general CPP material is different, have other special requirements, high-temperature cooking besides general binary copolymer, with block copolymer, high temperature resistance of it should be the best; The materials of aluminum plating CPP is best terpolymer. Some enterprises in order to save money, the request is not high, using polypropylene blown film as lining also enough. When producing thin film surface has to be edm processing, film surface tension is greater than the best 40 dyne/cm. Three, sealing film on the market supply of jelly, cold drink milk, yogurt, fruit and other food most is packed in plastic cups and plastic bottles, cups and bottles which are to thin film to sealing. Some requirements can be opened, and some don't. Don't reveal heat sealing layer is generally used in packaging, such as milk, fruit milk, a cup body or bottles on the root end is with high density polyethylene ( HDPE) Resin as materials. Lining material as long as the use and the cup body ( The bottle) The same material. On the one hand, want to have a better seal strength, on the other side and have the function to jie, other requirements about this kind of comparison, the choice of heat sealing layer is very important. Together with two functions of EVA material is modified. EVA - ethylene/vinyl acetate copolymer, it with polypropylene and polystyrene has remarkable caking property, but it differs from the molecular structure of polypropylene and polystyrene, when heat sealing adhesive, two kinds of resin can't slack off, osmosis, fused together. Constitute a significant bond interface. So choose modified EVA as capping the heat sealing film layer, both satisfy the heat sealing strength, and can be stripped of yi jie. Four, other packaging of heat sealing material in some special occasions, such as coffee, meat packing, packaging, etc. , will use some other heat sealing materials, such as ionic polymer, EAA ( Ethylene acrylic acid copolymer) 、EEA( Ethylene - ethyl acrylate) 、EMAA( Ethylene - methyl acrylic acid) And so on. These special materials need to be imported from Europe and the United States, Japan and other developed countries, was less in the domestic use. However, along with our country national economy fast turn, also more and more high to the requirement of packaging materials. The use of these other heat sealing materials is becoming more and more widely. Five, co-extrusion film with the open of packaging industry, the intense market competition, monolayer film more disadvantages gradually, constraints, the popularization and application of the resin. Using co-extrusion blown film or co-extrusion flow process produces co-extrusion film, has the following benefits: 1, the decline in yield capital such as function in order to improve the heat sealing film, now there are many manufacturers use LDPE and mLLDPE blending to produce films. When using a single equipment to produce material capital increase per ton, than the multi-layer co-extrusion equipment to produce high degree of material capital increase per ton.