How to distinguish the quality of materials in the wholesale of disposable plastic bags?
Publish Time: 2025-04-15
In the wholesale of disposable plastic bags, the quality of materials directly affects the cost, use effect and compliance. To distinguish the material, it is necessary to make a comprehensive judgment from three aspects: raw material composition, physical properties and compliance.
Raw material composition is the basis. High-quality plastic bags are mostly made of polyethylene (PE) or polypropylene (PP). PE material has high transparency and good toughness, which is suitable for food packaging; PP material is thicker and has stronger temperature resistance, which is suitable for high-temperature scenes such as kitchens. Be wary of plastic bags made of inferior recycled materials or doped with polyvinyl chloride (PVC). PVC will release toxic gases such as hydrogen chloride at high temperatures, and it is difficult to degrade and does not meet environmental protection standards. During wholesale, combustion tests can be used to assist in judgment: when pure PE material burns, the dripping liquid is waxy and there is no black smoke; plastic bags containing PVC burn and emit black smoke and have a pungent smell.
Physical properties determine practicality. High-quality plastic bags should have a certain weight and toughness, and only deform without breaking when torn hard. Plastic bags can be tested by immersing them in water. High-quality PE/PP materials have a lower density than water and will float on the water surface. If they sink to the bottom, impurities or recycled materials may have been added. In addition, the difference can be felt by touching the surface: the surface of high-quality bags is smooth and dense, while that of low-quality bags is rough and sticky, and may even have black spots or cracks. These characteristics directly affect the load-bearing capacity and leak-proof performance. For example, when loaded with 20 kilograms of water, low-quality bags may break due to the thin and brittle material.
Compliance is the bottom line. It is necessary to confirm whether the plastic bag meets the food safety standards. For example, food-grade plastic bags should be marked with "QS" or "food-only" and comply with the GB/T 24984-2010 standard. If used for export or specific industries, it must also meet the degradable requirements, such as passing the JJ mark or PLA, PBAT and other degradable ingredient certification. Be wary of "pseudo-degradable" bags. Such products only add a small amount of degrading agents, which are actually difficult to degrade and pollute the environment.
Supplier qualifications and reputation are equally important. Give priority to old factories in the industry or suppliers on large platforms, and check their production qualifications, quality inspection reports and buyer reviews. The quality can be verified by sampling tests, such as hanging a heavy object for 1 hour to observe whether there is leakage, or simulating transportation stacking to test the compressive capacity.
When wholesale, it is necessary to consider the purpose, cost and environmental protection requirements. For example, PE material is preferred for food packaging, and PP material can be selected for kitchen scenes; if it is necessary to comply with the plastic ban policy, it is necessary to turn to a degradable solution. By strictly selecting materials, it can reduce the risk of use and enhance the brand image.
