PE plastic bag composition
The plastic we usually use is not a pure substance. It is made of many materials. Among them high polymer (or say synthetic resin) it is the main composition of plastic, in addition, in order to improve the performance of plastic, but also in the polymer add a variety of auxiliary materials, such as filler, plasticizer, lubricant, stabilizer, colorant, etc., to become a good performance of plastic.
1. Synthetic resin
Synthetic resin is the most important component of plastics, and its content in plastics is generally 40% ~ 100%. Resin is often considered a synonym for plastic because of its high content and because the nature of the resin often determines the nature of the plastic. For example, polyvinyl chloride resin and polyvinyl chloride plastic, phenolic resin and phenolic plastic confused. Actually resin and plastic are two different concepts. Resins are raw polymers that are used not only to make plastics, but also for coatings, adhesives and synthetic fibres. Most plastics, however, require the addition of other substances in addition to their main component, the resin.
Filler, also known as filler, can improve the strength and heat resistance of plastics, and reduce the cost. Adding wood powder to phenolic resins, for example, can significantly reduce costs, making phenolic one of the cheapest plastics, and significantly improve mechanical strength. Fillers can be divided into organic fillers and inorganic fillers, the former such as wood powder, rags, paper and various fabric fibers, the latter such as glass fiber, diatomite, asbestos, carbon black and so on.
Plasticizer can increase plastic plasticity and softness, reduce brittleness, make plastic easy to process and shape. Plasticizer is generally can be miscible with resin, non-toxic, odorless, light, heat stable high boiling point organic compounds, the most commonly used is phthalate esters. For example, when the production of PVC plastic, if add more plasticizer can get soft PVC plastic, if do not add or less plasticizer (dosage <10%), get hard PVC plastic.
In order to prevent synthetic resin in the process of processing and use by light and heat decomposition and damage, extend the service life, to add a stabilizer in the plastic. Commonly used are stearate, epoxy resin and so on.
Colorants can give plastics a variety of bright and beautiful colors. Organic dyes and inorganic pigments are commonly used as colorants.
Lubricant is used to prevent the plastic from sticking to the metal mold during molding, and to make the plastic surface smooth and beautiful. Commonly used lubricants are stearic acid and calcium magnesium salt and so on.
Prevent plastic in the heating molding or in high temperature use process by heat oxidation, and make plastic yellow, hair crack
In addition to the above additives, plastics can also add flame retardants, foaming agents, antistatic agents, etc., to meet different requirements.