Blister packaging, plastic film packaging, PP film, PET film, PVC film plastic film is not a pure substance, it is made of many materials.
The polymer (or synthetic resin) is the main component of plastic. In addition, in order to improve the properties of plastics, it is necessary to add various auxiliary materials in the polymer, such as filler, plasticizer, lubricant, stabilizer, colorant and so on, so as to become a good plastic material.
1. Synthetic resin
Synthetic resin is the most important component of plastics, and its content in plastics is generally 40% to 100%. Because of the large content and the nature of resins often determine the properties of plastics, resins are often regarded as synonyms for plastics. For example, PVC resin and PVC plastics, phenolic resin and phenolic plastics confuse. In fact, resin and plastic are two different concepts. Resin is an unprocessed raw polymer. It is used not only for plastics but also for paints, adhesives and synthetic fibers. In addition to a very small proportion of plastic containing 100% of the resin, the vast majority of plastics, in addition to the main components of resin, but also need to add other substances.
Filler is also called filler, it can improve the strength and heat resistance of plastics, and reduce the cost. For example, the addition of wood powder in phenolic resin can greatly reduce the cost, make phenolic plastics one of the cheapest plastics, and also significantly improve mechanical strength. Packing can be divided into two kinds of organic fillers and inorganic fillers, the former such as wood powder, shret, paper and various fabric fibers, the latter such as glass fiber, diatomite, asbestos, carbon black and so on.
Plasticizers can increase plasticity and softness of plastics, reduce brittleness, and make plastics easy to process and shape. Plasticizer is generally mixed with resin, non-toxic, odorless, light, heat stability of high boiling point organic compounds, the most commonly used is two phthalate esters. For example, when PVC plastics are produced, soft PVC plastics can be obtained by adding more plasticizers. If no or less plasticizers are added (<10%), hard PVC plastics are obtained.
In order to prevent the decomposition and destruction of the synthetic resin from being affected by light and heat during the processing and using, and to prolong the service life, stabilizer should be added to the plastic. It is commonly used as stearate, epoxy resin and so on.
Colorants can make plastic with various bright and beautiful colors. Common organic dyes and inorganic pigments are used as coloring agents.
The role of lubricants is to prevent plastic from sticking to metal molds while molding, and to make the surface of plastics smooth and beautiful. Commonly used lubricants are stearic acid and calcium magnesium salts.
Prevent plastic from being heated and oxidized during heating or high temperature use, so that the plastics will become yellow and crack.