1. Polyethylene film should not be used as food package for frying vegetable oil or food containing vegetable oil
In order to enhance or complement the properties of PE (polyethylene) plastic film in actual tape casting or blowing drawing, high pressure polyethylene, low pressure polyethylene and linear polyethylene are often mixed in proportion. The film is named after which substance accounts for a large proportion. For example, milk packaging film contains high-pressure polyethylene components, known as high-pressure polyethylene film. Yogurt, convenience bag packaging film contains more ingredients of low-pressure polyethylene, it is called low-pressure polyethylene plastic film.
Although PE (polyethylene) film has good air permeability (packaging fruits and vegetables has the effect of keeping water and discharging carbon dioxide), after contacting with vegetable oil, PE (polyethylene) film will quickly penetrate, swell and change color. For example, packaging food containing vegetable oil will not only greatly shorten the shelf life of food, but also long-term contact with vegetable oil and PE (polyethylene) film“ Therefore, PE (polyethylene) film should not be used to package fried food and food containing vegetable oil, as well as melon seed, dried fruit seed and nut seed containing oil.
2. PE plastic film under five layers co extrusion is not suitable for milk packaging
Co extrusion PE (polyethylene) plastic film packaging, the current market popular milk packaging, dairy products packaging, soy sauce, vinegar packaging is a typical co extrusion plastic film packaging. Transparent non printing vacuum or cooking bags are also used for coextruded plastic film packaging. Although the current milk packaging uses black and white co extrusion plastic film with white outside and black inside, the shelf life has been extended. However, if the three-layer coextrusion plastic film is used, due to the lack of barrier layer, it can hardly reach the shelf life marked on the package.
The five layer coextrusion with EVOH barrier layer and the plastic film coated with PVA barrier layer can prolong the shelf life, but the cost is higher. In today's market with only price competition, some enterprises use two or three layers of coextrusion black and white plastic film and symbolic PE film coated with barrier material to package milk, dairy products, soy sauce and vinegar. Then the PE (polyethylene) film mixed with black masterbatch is in direct contact with milk, dairy products, soy sauce and vinegar, and the inert carbon black pigment will penetrate (the package will be contaminated). So symbolically coated with barrier material of plastic film, can cope with the inspection and testing, but can not play a barrier role, also can not guarantee the shelf life of the contents.

At present, many PE (polyethylene) convenience bags and hand tear inner packaging bags on the market are thickened. However, in order to reduce costs, many bag manufacturers add a lot of fillers. The transparency and opening of the bags become worse, the strength is lower, and the smell is bigger. Although the bags are printed with environmental protection and food safety signs and words, they actually do not use degradable materials, nor do they The use of environmentally friendly ink printing, not only increases the production cost, but also increases the solvent residue, security is also worrying.

3. Al foil cannot be replaced by DAL vacuum aluminizing film in plastic flexible packaging
Al foil has bright metallic luster, non-toxic, tasteless, excellent light shielding, reflective rate up to 95%, stable at high temperature and low temperature, does not shrink and deform in the range of 73-371 ℃; it has good barrier property, gas, oxygen, moisture and fragrance retention, and is an excellent middle-level substrate film for high-grade packaging; It is mainly used for high-grade packaging and blister packaging of drugs, moisture-proof and fragrance retaining paper of cigarettes, high-grade packaging of chocolate, anti leakage packaging of daily chemical products, sealing film of instant noodle bowl, sealing trademark of beer and champagne, paper / aluminum / plastic composite packaging of milk and milk products and juice, cooking packaging and integration of food and condiments, cooked meat, grilled chicken, roast duck, etc Circuit board moisture-proof, anti-static packaging, etc.
Dal vacuum aluminizing film is a kind of product that more than 99.99% of high purity aluminum is deposited on the plastic film of bpet (biaxially oriented polyester), BOPP (biaxially oriented polypropylene), PVC (polyvinyl chloride), CPP (cast polypropylene), CPE (chlorinated polyethylene) plastic films under vacuum condition. The gas and oxygen resistance of aluminized film mainly depends on the substrate film itself, not the aluminum coating, which only plays a decorative role. However, the barrier properties of BOPP, PVC, CPP and CPE films are not good. Therefore, the vacuum aluminized films made from the above-mentioned substrates cannot be used for vacuum packaging. Only after the plastic films with good barrier properties are compounded or aluminized can they be vacuum packed. Bpet (biaxially oriented polyester) vacuum aluminized film can only be made into vacuum packaging, but not cooking packaging. In order to reduce the cost, it is wrong to use aluminized film instead of metal aluminum foil packaging.
The biggest feature of aluminized packaging is its excellent decoration. Therefore, the pattern design should be hollowed out as far as possible, so that the bright silver and the dazzle color after dyeing can be fully displayed. The unreasonable design of the packaging pattern, such as aluminum plating composite packaging covered with white ink or spot color ink printing, will increase the residual amount of ink and solvent, reduce the composite firmness of plastic composite film, and is not conducive to improving the printing speed, but will increase the packaging cost. It is not guaranteed that the food in the package reaches the shelf life indicated on the package.
In addition, although the vacuum aluminized plastic film has good mechanical properties, flat and bright aluminum surface, is not easy to produce pinholes, and has strong decoration, it has certain functions of gas barrier, light shielding and shielding. It can complement the disadvantages of calendered aluminum foil, such as low strength, easy to tear, easy to break when folded, easy to produce pinholes, and not resistant to acid and alkali. However, the aluminum layer of vacuum aluminized plastic film has poor water resistance, and will fall off when wet Falling and dealumination will cause delamination of composite packaging bags. In addition, the aluminum layer is too thin (the aluminum coating is only 400 μ m), that is to say, only about 1 kg of high-purity aluminum is needed for 50 000 m2 plastic film, and its shading and shielding properties are far lower than that of rolled aluminum foil (metal pure aluminum foil), so the aluminum film can not replace calendered aluminum foil in the use of plastic composite packaging substrate.
4. Pet (polyester) film can not replace PA (nylon) film for cooking packaging
The function of cooking packaging is to kill the fungi in the food in the package through the cooking high temperature, and prolong the shelf life of the packed food; only when the high temperature is transferred to the food in the package through the packaging, the fungus will be killed. PA (nylon) film has high water vapor transmission rate, and aluminum foil is a good thermal conductor. However, the thermal conductivity of PET film with excellent insulation and gas barrier is not good, and its water vapor permeability is very low, which can prevent or reduce the introduction of cooking temperature; In addition, pet (polyester) film itself has high hardness and stiffness, and the air is not easy to be exhausted. Although it has excellent barrier property, it weakens the effect of cooking and sterilization. Therefore, PET film is only suitable for vacuum packaging, not cooking packaging.
Using PET (polyester) film instead of PA (nylon) film to make cooking packaging or adding four layers of composite pet (polyester) film can only reduce the cost, but it has no better sterilization effect and longer shelf life than PA (nylon) / Al (metal aluminum foil) / CPP (cast polypropylene) three-layer composite cooking packaging.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.