Source: Link Testing Instruments Co.,Ltd.
What performance should be focused on in the packaging of finished nutritional powder in bags?
(1) Sealing performance - to prevent air leakage, leakage and other problems in the finished packaging due to poor sealing. It can be verified by sealing performance (negative pressure method) test.
(2) Sealing strength of the heat seal—to prevent leaks and bag breaks in the finished product package due to leakage of the heat seal or excessive heat sealing. It can be verified by heat seal strength test.
(3) Performance of resistance to internal gas impact——to prevent packaging from being broken due to poor resistance to gas impact. It can be verified by burst pressure test, and the parts with poor pressure resistance of the packaging can be found through a series of tests.
(4) Drop resistance performance - prevent the bag from breaking when the package falls. Verified by drop resistance test.
(5) Pressure resistance - prevent the package from breaking when it is stacked or squeezed by external force. Verified by withstand voltage performance test.
(6) Gas component content in the package—for nitrogen-filled or modified atmosphere packaging, the gas component ratio in the package has an important impact on the quality preservation effect of the nutritional powder. It can be verified by headspace gas analysis test.
How to test the airtightness of nutritional powder metal cans?
At present, there is no test method for the airtightness of metal cans for packaging nutrition powder in China, while SN/T 0400.4-2005 "Import and Export Canned Food Inspection Regulations Part 4 Containers" and GB/T 4789.26-2003 "Food Sanitation Microbiology Examination of Canned Foods" The test method for the airtightness of tinplate cans is specified in Appendix B of Food Commercial Sterility Inspection, which can be used as a reference for the airtightness test of nutritional powder metal cans.
• Pressurized leak test method: seal the empty tank well, and open a hole in the tank body, immerse the tank body in water, inject air into the tank from the hole, when the pressure inside the tank reaches 68 KPa or 70 KPa , keep it for 2 minutes, and check whether there are continuous air bubbles outside the tank.
• Decompression leak test method: inject 80% ~ 90% steamed aqueous solution into the empty tank, seal the empty tank with a glass plate with a sealing ring, and evacuate the inside of the tank, when the pressure reaches 68 KPa, keep After 1 min, check whether there are continuous air bubbles inside the tank.
The above method is for empty metal cans. If it is necessary to test the airtightness of the finished nutritional powder cans, a certain amount of nitrogen or carbon dioxide may be filled in the finished product packaging, so the specific test pressure can be adjusted according to the actual situation.
What performance should be paid attention to when the soft plastic packaging used for nutrition powder enters the factory?
(1) Barrier properties
• Barrier to oxygen and water vapor——to prevent the nutrition powder from being exposed to too much oxygen and water vapor due to the poor barrier to oxygen and water vapor of the packaging material and the high permeation rate, resulting in a "hala" smell , agglomeration, mildew and other quality problems. It can be verified by oxygen transmission rate and water vapor transmission rate.
• Resistance to rubbing——For aluminum-plastic composite films or aluminum-coated composite films, if the composite film has poor rub resistance, creases, pinholes and other problems will easily form, resulting in a decrease in the barrier properties of the composite film. It can be verified by comparing the oxygen transmission rate before and after rubbing.
• Barrier property to nitrogen and carbon dioxide—for nitrogen-filled packaging or modified atmosphere packaging, if the packaging material has poor storage capacity for nitrogen and carbon dioxide gas filled inside, and the permeation rate is high, it will lead to nitrogen-filled or modified atmosphere packaging. The shelf life of the packaging is reduced. It can be verified by nitrogen permeation rate and carbon dioxide permeation rate.
(2) Physical and mechanical properties
• Uniformity of thickness—uniformity of thickness is the basis for other uniform and good properties of packaging materials. Verify by thickness test.
• Flexibility——to prevent the bags from breaking when they are dropped or stacked. It is verified by tests such as transverse and longitudinal tensile elongation, elastic modulus, and pendulum impact energy.
• Smoothness——to prevent problems such as slipping, deviation, and unsmooth rolling during bag making. Verified by friction coefficient test.
(3) Hygienic performance
• Residual amount of organic solvent - if there is a large amount of residual organic solvent in the packaging material, the residual organic solvent will slowly migrate into the nutritional powder after it is used to package the nutritional powder, and the nutritional powder will be polluted and have an odor. Verified by solvent residual test.
What should I do if there is a peculiar smell in the plastic flexible packaging of health products?
Quality problems: Health care products packaged in composite soft plastic materials often have a pungent odor.
• Improper control of lamination process - for solvent-based dry lamination membranes, the adhesive needs to be dissolved in organic solvents (alcohols, ketones, esters, benzenes) before lamination, and then coated and laminated , and through subsequent drying, aging and other processes, the organic solvent is fully volatilized. If the composite process is not properly controlled, some organic solvents will remain in the composite film, and after contacting with the health care product, it will slowly migrate into the health care product, causing the health care product to have an odor.
• Improper printing process control – similar to the lamination process, inks are also printed in solvents. Therefore, if the printing process is not properly controlled and the solvent is not fully volatilized, it will also cause the problem of solvent residue in the composite film.
• Poor quality of raw materials - if the quality of resin raw materials used to produce film materials is poor or the quality of small molecular substances added is poor, more odorous substances will be introduced into the composite film, which will indirectly lead to the appearance of packaged health care products. smell.
• Adhesive quality is poor - if the quality of the adhesive is poor, it will produce toxic substances such as toluenediamine when it passes through the high temperature process.
——Pay attention to the monitoring of hygienic properties such as solvent residues, toluenediamine content, potassium permanganate consumption, and evaporation residues.
——Select solvent-free inks, high-quality adhesives, and improve compounding and printing processes.
Typical quality cases:
——Test sample: Composite film for donkey-hide gelatin paste packaging (the customer reported that there was a strong smell of paint when opening the finished product packaging).
——Targeted detection items: solvent residues.
——Test results: The total amount of residual solvents is 7.8 mg/m2, of which the residual amount of benzene solvents is 0.91 mg/m2. Much higher than the average of similar products on the market. Therefore, the high residual solvent is an important reason for the peculiar smell of health care products.
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