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How to prevent frozen food packaging bags from breaking in the freezing environment?

Due to the characteristics of the contents or the quality of the product, some products need to be stored in a low temperature freezer, such as ice cream, ice cream, quick-frozen food, frozen fish, etc. However, the low temperature environment inhibits the growth and reproduction of microorganisms, ensuring that the productWhile the quality is intact, it also brings challenges to the sealing and integrity of the packaging during transportation, storage and sales. Broken packaging is one of the most common freezer bag quality problems.Cause Analysis:Under low temperature conditions, the mobility of the molecular chain inside the polymer material of the flexible packaging bag is reduced, and the ability to resist external deformation is reduced. Macroscopically, the impact resistance is weakened, which causes the flexibility of the flexible packaging to decrease and the brittleness to increase. , It is very easy to have problems such as broken bags and air leakage.So how to improve the flexibility of the packaging material at low temperature and reduce the breakage rate?First of all, packaging materials should be reasonably selected according to the characteristics of the contents and cost control. E.gOPP/LDPEThe material is moisture-proof, cold-resistant, low-temperature heat-sealing tensile force, and cost-effective, and is a commonly used low-temperature material;PA/LDPEIt has good cold resistance, impact resistance and puncture resistance, and is suitable for product packaging with relatively hard contents, but the cost is high. in addition,PE,PET/PE,BOPP/PE, BOPP/CPPOther materials can also be selected according to actual needs.Second, monitor the cold resistance of the packaging material. Cold resistance is an important performance index of flexible plastic packaging materials, and it is an assessment of the flexibility of packaging materials under low temperature conditions.The changing physical properties are the indicators that should be paid attention to in the packaging of products circulated in low temperature environment. If the cold resistance of the material does not meet the requirements, under the condition of low temperature, the material cannot maintain the original physical properties, resulting in the rupture of the packaging bag andCracking, unable to meet the protection of the contents. By selecting appropriate resin raw materials, improving the processing technology of packaging materials, adding an appropriate amount of plasticizers, and selecting packaging materials with good low temperature resistance, it can be effectively improved.The cold resistance of the packaging bag prevents the increase of the damage rate of the packaging bag in the low temperature environment.The cold resistance can be tested by the pendulum impact test by comparing the standard environmental conditions with the low temperature environment.(mostly minus18The anti-pendulum impact energy measured at ℃), the cold resistance should not be less than a certain fixed percentage ratio, such asQB/T 1871-93″Two-way stretch nylon (BOPA)Low-density polyethylene(LDPE)The cold resistance of the material specified in the “Composite Film and Bag” should not be less than60%, the detection method is as follows:put the sample in-18placed at ℃2 hours, press GB 8809The pendulum impact energy of the film is specified to be measured, and the cold resistance is calculated by the following formula, taking two significant figures.In addition, do not ignore the comprehensive physical performance testing of packaging bags. Such as tensile properties, packaging puncture resistance testing. Flexible packaging materials for frozen food should have a certain flexibility, such as at room temperature, the flexibility of the material is poor, elongationIf the rate is low, when there is air pressure inside the finished product packaging, the packaging material is easy to form resistance.

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