The quality of food packaging bags in the flexible packaging industry, especially the sanitary quality is directly related to the safety of the food packaged, so it is necessary to ensure that the raw materials and additives used meet the quality requirements of the management system. It is necessary to improve and strictly implement the industry and national standards for packaging film bags, strengthen the inspection and supervision of food packaging, prevent unqualified food packaging from flowing into the market, and strengthen management to ensure the healthy development of the flexible packaging industry.
Food packaging bags are the most widely used packaging containers in the food packaging industry. Food packaging bags can be generally divided into single film bags and composite film packaging bags. Food packaging single film bags are mainly polyethylene blown film, and some It is a polypropylene film, and the main standards for the inspection of these film bags are: GB / T4456-1996 "Blowing Film for Polyethylene for Packaging", GB12025-1989 "Blowing Film for High Density Polyethylene", QB / T2461-1999 "Degradable polyethylene film for packaging", GB9687-1988 "Hygienic standard for polyethylene molded products for food packaging", GB9688-1988 "Hygienic standard for polypropylene molded products for food packaging", etc. GB9685-1994 "Standard for the Use of Auxiliary Agents for Food Containers and Packaging Materials", in the hygienic standard of this auxiliary agent, it specifies 17 categories of additives, solvents, adhesives, etc., the names and the highest use of 58 specific substances the amount.
   The inspection items of food packaging single film bags are mainly divided into the following categories:
The appearance shall not have any defects such as bubbles, perforations, water marks, burst tendons, poor plasticization, fisheye stiffness, etc. which are obstructive to use.
Specification, width, length, thickness deviation should be within the specified range.
The physical and mechanical properties include tensile strength and elongation at break. It reflects the ability of the product to stretch during use. If this item is unqualified, food packaging bags are prone to cracking and damage during use.
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1. Hygienic performance
Including evaporation residue (acetic acid, ethanol, n-hexane), potassium permanganate consumption, heavy metals, decolorization test. Evaporation residues reflect the possibility that residues and heavy metals will be precipitated when the food packaging bag encounters vinegar, wine, oil and other liquids during use. The residues and heavy metals will adversely affect human health. In addition, the residues will directly affect the color and aroma of the food. , Taste and other food quality.
Degradation performance: According to the different types of degradation of products, it can be divided into photodegradation type, biodegradation type and environmental degradation type. The degradation performance reflects the ability of the product to be accepted by the environment after being discarded. If the degradation performance is good, the bag will break, differentiate and degrade under the combined action of light and microorganisms, and eventually become debris, which is accepted by the natural environment; If the degradability is not good, it will not be accepted by the environment, thus forming "white pollution".
   In addition to the above-mentioned standards, the main standards for the inspection of food packaging composite bags should also be followed: Packaging industry standards BB / T0003-94 "High-temperature cooking film, bag", GB / T0004-1998 "Resistant to cooking Thin, Bag ", GB9683-1988" Hygienic Standard for Compound Food Packaging Bags ", Light Industry Standard QB / 1871-93 Biaxially Stretched Nylon (BONY) / Low Density Polyethylene (LDPE) Composite Film and Bag; QB / T219796 Mustard Composite films and bags for packaging; BG13113-1994 hygienic standards for polyterephthalate molded products for food containers and packaging materials.
   The inspection items of food packaging composite film bags are mainly divided into the following categories:
The appearance should be smooth, without scratches, scalds, air bubbles, oil breaks and wrinkles, and the heat seal should be flat and free of false seals. The film must not have cracks, pores and composite layer separation. No pollution such as impurities, foreign objects and oil stains.
The bagged soaking liquid shall not have odor, odor, turbidity and discoloration.
   2. Physical and mechanical properties
Including tensile strength and elongation at break, it reflects the product's ability to withstand stretching during use. If this item is unqualified, food packaging bags are prone to cracking and damage during use.
In addition, it also includes gas permeability indicators such as gas permeability; oil resistance index, heat resistance, cold resistance, and medium resistance; the sealing peel force of the bag, the pressure resistance and the drop resistance of the bag, which reflect the food packaging bag ’s Reliability of inner packaging protection.
   Hygienic properties include evaporation residues (acetic acid, ethanol, n-hexane), potassium permanganate consumption, heavy metals, and decolorization tests.
It should be pointed out that in addition to the above-mentioned corresponding sanitary standards, food packaging materials in China also have two laws and regulations: one is the "Food Hygiene Law of the People's Republic of China", and the other is "Administrative Measures for Plastic Products and Raw Materials for Food".
   The Food Sanitation Law is more comprehensive than the management method, and it is a comprehensive law. The latter is specialized, and refers only to plastic products and raw materials. The management scope is limited to various plastic utensils, containers, production pipes, and transportation that come into contact with food. Packaging materials made of tapes and plastics and the synthetic resins and additives used. The so-called plastic tableware refers to plastic products such as spoons, spoons, chopsticks, etc. that have been in contact with food for a short time but have to be used repeatedly. The so-called window refers to plastic products containing food such as barrels, bottles, pots, cups, etc. The so-called production pipeline refers to the pipeline through which materials, especially liquid food or beverages flow, in the food processing process should also include storage and irrigation. The so-called conveyor belt refers to the carrier that transports food raw materials to the processing equipment, and the packaging material refers to single-piece and composite bottles, barrels, trays, roll films and bags, of which the roll film packaging cling film, capping film and manufacturing Bag film. All manufacturers of flexible food packaging and composite packaging materials should strictly implement this management method.
   China ’s raw material health standards include heavy metal content (in terms of lead), evaporation residue, potassium permanganate consumption, and decolorization indicators, while foreign indicators include heavy metal content, cadmium, arsenic, mercury and other heavy metals Content, phenol and amine content, etc. The measurement method is to soak the plastic with various liquids, and then measure the migration of related components of these liquids. The choice of liquid depends on the type of food container and packaging materials that contact the food. According to different physical conditions, chemical substances are generally used, such as distilled water (representing neutral food), 4% ethyl (vinegar) acid (representing acidic food), 8 % ~ 60% ethanol (representing foods containing alcohol), n-hexane (representing oily foods); consumption of potassium permanganate or soaked in distilled water solvent after soaking or oxygen consumption (representing total organic substances and The amount of insoluble substances), evaporation residue (representing the amount of total soluble and insoluble substances migrating into food); decolorization test; other based on arsenic, fluorine, heavy metals (lead, cadmium, antimony, germanium, cobalt, Determination of harmful elements such as chromium, zinc), organic monomer residues, cracking products (vinyl chloride, styrene, phenols, nitrile butadiene rubber, formaldehyde) additives, aging products and so on.
   The sanitary standards for products, in addition to the specific indicators of evaporation residues, potassium permanganate consumption, and heavy metal content, in the (hygienic standards for compound food packaging bags, there is an indicator that the content of toluene diamine must not exceed 0.004 mg / L, toluene di Ammonia is a trace amount of harmful substances in the binder, and it is a carcinogen. It will affect the hygienic performance of the entire system, so toluene diamine must be strictly controlled, and the regulation should not exceed 0.004mg \ L. In the standard of composite film bags There is also a provision that the residual solvent should not be greater than 10mg / m2, such as GB10004 and GB10005, where the residual amount of toluene should not be greater than 3mg / m2. This is because in recent years, the international odor and potential toxicity requirements for packaging materials have become more stringent related.
   The processing of plastic film bags must pass through the heating pass, and plastics have problems of cracking, oxidation, degradation, and deterioration when heated. Therefore, when processing plastic films or bags with resin, antioxidants, Additives such as heat stabilizers. Some packaging film bags also require anti-static, anti-condensation, high-smoothness due to the packaging process and the needs of machinery or content, so anti-static agents, anti-fogging agents, lubricants, opening agents and other additives are also added. All these additives must first be tested by GB15139 "Food Safety Toxicology Evaluation Procedure" to prove that they are non-toxic before they can be used, but there is also a limit on the amount of addition. Therefore, in the product, these low-molecular-weight substances that can be extracted, that is, evaporation residues, or things that can be oxidized and deteriorated, that is, the consumption of potassium permanganate cannot exceed the prescribed amount, and cannot be used if it exceeds . Therefore, there must be corresponding hygienic standards for molded products, the purpose of which is to prevent the misuse and abuse of additives, that is, to better ensure that the materials that are directly packaged and contact with food have a high degree of hygienic safety performance.
   In the composite packaging materials, in addition to resins and additives, there are also inks and adhesives. At present, there is no separate sanitary standard, nor is there a unified national product standard, only the "Enterprise Standards" of various production enterprises.
At present, the development stage of technical standards in flexible packaging in China is still not suitable for the development of industry products. For example, the structure of composite flexible packaging materials is developing rapidly. The only materials used are PE, PP, PVC, PVDC, PET, PA, EVOH, EVA , EEA, EMA, ionic polymer and various inks, adhesives and other dozens of materials, the existing composite packaging material standards only involve BOPP, LDPE, BOPA, PET, aluminum foil and other materials, and many other structures of composite film materials There is no standard to follow for the inspection, and it can only be carried out with reference to the existing standards and relevant standards.
   Secondly, the new use and post-processing methods of composite flexible packaging are constantly being introduced. According to different packaging contents and different application fields, there are many requirements. For example, in the field of food packaging bags, in addition to traditional pasteurization, boiled, 121 ℃ cooking In addition to 135 ° C cooking, microwave packaging, vacuum packaging and other different applications, the physical and chemical effects on food packaging bags are different from the usual boiling and heating, so it is not enough to only have the technical standards for cooking film bags. There is also a lack of corresponding industry standards or national standards in composite flexible packaging raw materials and auxiliary materials such as various films, adhesives, solvents, and additives.
The quality of food packaging bags in the flexible packaging industry, especially the quality of hygiene, is directly related to the safety of the food packaged, so it is necessary to ensure that the raw materials, additives, and management systems that meet the quality requirements are used. Improve and strictly implement the industry and national standards for packaging film bags, strengthen the inspection and supervision of food packaging, prevent unqualified food packaging from flowing into the market, coordinate and strengthen management, and ensure the healthy development of the flexible packaging industry.
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