The anti-aging of plastic woven products, especially the anti-aging of products such as container bags, has been in the woven enterprise. The application of the aging system has been learned. If used well, it can double the value of the products at the end of the hall. Behalf Jixing was compensated by the wealthy. Anti-aging involves multiple disciplines such as polymer chemistry, polymer physics, and plastic materials engineering. The analysis and treatment of difficult problems in this chapter are dedicated to answering these practical difficult problems from the perspective of theory and practice. In this chapter, a large number of reliable formulas for anti-aging applications of plastic end products are given.
Why do plastic woven materials and products age?
The materials are all polymer materials, and polymer materials will inevitably undergo constant deterioration during their synthesis, transportation, storage, processing and final product processes, and their physical performance indicators will decline, that is, aging. The performance of aging such as yellowing, loss of luster, surface cracking of the product, chalking (polypropylene), and more serious, the mechanical properties such as tensile strength, impact strength, flexural strength and elongation at break are greatly reduced, thereby losing Use performance.
From a chemical point of view, regardless of whether the polymer material is natural or synthetic, due to its macromolecular chain structure, some parts of it have some weak bonds, and these weak bonds become a breakthrough in chemical reactions. The aging of plastic woven raw materials and products is nothing more than natural conditions, starting from weak bonds to carry out chemical reactions, such as oxidation reactions, and thus cause a series of other chemical reactions. As a result, the molecular structure of the polymer material changes, such as chain scission, a decrease in relative molecular weight or cross-linking, which deteriorates the performance of the material and makes it unusable.
There are many factors for the natural aging of plastic woven raw materials and products, such as heat, ultraviolet light, wind, frost, snow and rain, etc.Plastic woven products use more aging factors, such as long-term load, stacking extrusion force, and various external machine forces. , Electrostatic force and corrosion of contents, etc.
The most common aging can be divided into two categories: thermal oxidative aging and photooxidative aging. There is temperature, and with the presence of oxygen in the air, there is thermal oxygen aging; when there is light, that is, ultraviolet radiation, and with the regas in the air, there is photooxygen aging. During the whole process of storage, transportation, processing and use, the most exposed to heat, oxygen and sunlight (ultraviolet rays) in the environment.
Plastic woven enterprises should note that the pellets of plastic woven polypropylene raw materials have been added with a chemical agent during the production process. The resin manufacturer guarantees that there will be no major aging during production, storage and transportation. However, the powder is not added with anti-aging agents, and the plastic braiding enterprise should not store it for too long, because the surface layer of the powder will age seriously with the storage time. , Polyethylene used in plastic woven materials, generally do not need to consider storage and transportation aging.