Views:6 Author:Vera Publish Time: 2018-05-14 Origin:Site
Due to the influence of external conditions and the effect of light and heat, the waste plastic products have aged to varying degrees in the process of use. Among them, all kinds of additives have different degrees of loss. For example, the loss of plasticizer in recycled soft PVC is great. The properties of recycled products are much worse than those of new materials. In order to improve the quality of recycled waste plastics as much as possible, it is necessary to re-add a certain amount of auxiliaries in the process of remaking, to improve the molding and mechanical properties of waste plastics. So how to control the amount of additives?
Selection of additives
The selection of additives is determined by the variety of plastics and the degree of aging.
The new polyolefin materials are usually processed with a small amount of additives, such as antioxidant, ultraviolet absorbent and so on. When the waste is regenerated, only a small amount of colorant can be added. So the formula is easy to determine. Unless such plastics are severely aged and hardened and brittle, the ingredients need to be determined on a case-by-case basis.
The composition of PVC plastics is complex, especially soft PVC, which contains many kinds of additives, such as plasticizer, stabilizer, ultraviolet absorbent, lubricant and pigment, among which the amount of plasticizer is the most. The products are affected by the weather conditions such as light and heat, the plasticizer gradually seeps out, the products harden, especially the physical properties decline greatly, and gradually aging, which can not meet the requirements of use and become a waste product. It is necessary to supplement enough plasticizers and other auxiliaries to restore their mechanical properties to the maximum extent, so it is very important to determine the formula reasonably.
The amount of plasticizer is mainly determined by the hardness of recycled PVC products, so the ratio of hard and soft in recycled PVC waste products should be considered. The residual amount of plasticizer in PVC film, leather and wallpaper is very different from that in hard pipe, profiled material and so on, so long as the hard and soft recovery rate is mixed with each other and the mixing ratio of the two is adjusted, can meet the requirements of the hardness of recycled products, can reduce the amount of plasticizer, or even no plasticizer.
Principle of selecting additives
The general principle of selecting auxiliaries in batching is to ensure that recycled products have certain properties to meet the requirements of use, and do not cost too much. Generally speaking, consider the following points:
First, because of the low price of waste plastics and recycled products, the additives should also be cheap.
Secondly, because waste plastics are often a mixture of various color wastes, dark colorants are generally added in the process of regeneration, so the color and appearance of the auxiliaries selected are not high.
Finally, the additive should be able to meet certain performance requirements of recycled products.
In general, the waste plastic additives should be controlled in a certain amount, and the plastic components should be taken into consideration. This requires us to understand the knowledge of waste plastics in an all-round way and to make good use of them in the future.