Under natural conditions, such as direct sunlight, plastic bulk bags lose 25% of their strength after one week and 40% after two weeks, rendering them essentially unusable. This means that the proper storage and care of plastic bulk bags is crucial.
Plastic bulk bags are made from polyethylene or polypropylene through drawing, weaving, sewing, or pasting, and typically have a carrying capacity of 25-50 kg. Due to their excellent tensile strength, low price, and ease of transportation, they are widely used for packaging powdery and granular materials such as cement, chemical raw materials, fertilizers, minerals, grain, and sugar. Their use has been increasing year by year in recent years.
Additionally, after packaging cement in plastic bulk bags, leaving them in direct sunlight accelerates the loss of their strength. High temperatures (container transportation) or rain during storage and transportation can also weaken their strength, rendering them unable to meet the quality requirements for protecting the contents. Therefore, the proper transportation and storage conditions for plastic bulk bags are crucial. Therefore, both GB/T 8946 and GB/T 8947 stipulate storage and transportation conditions. Plastic bulk bags should be stored in a cool, clean room. During transportation, they should be protected from sunlight and rain and kept away from heat sources. The storage period should not exceed 18 months. In reality, plastic bulk bags can degrade after 18 months, so the shelf life of plastic bulk bag packaging should be shortened to 12 months.
Regarding the issue of recycled materials in plastic bulk bags, to ensure the packaging quality of plastic bulk bags, the aging of plastic bulk bags should be given high priority.
For this reason, the national building materials industry regulatory authorities have mandated that recycled and regrind materials be prohibited from being used in the production of plastic bulk bags. The amount of filler added should be strictly limited to no more than 5%. Furthermore, the lamination temperature must be strictly controlled to prevent accelerated aging of plastic bulk bags due to process issues. Excessive use of recycled materials is also a contributing factor to the aging of plastic bulk bags.