Analysis of the difference between old plastic and new plastic pipe products

After the recycled plastics are recycled, the performance is reduced to varying degrees, mainly caused by photoaging, oxidation and heat aging. The extent of performance degradation depends primarily on age and environment. Waste edges and waste products produced during the production of molding plants. The performance of the recycled material is reduced very little, and it can be used as a new material; the product used for indoor use and short-term use has little change in the performance of the recycled material; while it is used outdoors, it has a long life and poor environment (such as pressure, electric field, Product properties such as chemical media are poor and cannot even be recycled. Due to the heat aging during the regeneration process, the color of the recycled material is changed from shallow to deep. Industrial plastic products are not recommended for the incorporation or direct use of recycled materials. The following describes the performance changes of several commonly used plastic recycled materials.

Polystyrene

After the regeneration, the color turns yellow, so the recycled polystyrene is generally colored. The degree of decline of the performance of the recycled materials is proportional to the number of regenerations. The breaking strength has no significant change when the blending amount is less than 60%, and the limiting viscosity has no significant change when the blending amount is 40% or less.

Other plastic

The discoloration is obvious after aBS regeneration, but the performance does not change significantly when the blending amount is not more than 20-30%.

nylon

There is also a problem of discoloration and performance degradation in regeneration, and the amount of blending is preferably 20% or less. After regeneration, the elongation decreases, but the elasticity tends to increase.

Polyethylene

After the regeneration of polyethylene, the performance has decreased, the color turns yellow, and the anti-aging performance drops the most. After multiple extrusions, the viscosity of the high density polyethylene decreases and the viscosity of the low density polyethylene increases. The amount of blending that can be added during recycling is generally 8% or less.

Polypropylene

At the time of regeneration, the color is almost unchanged and the melt index rises. More than two times the color is increased and the melt index is still rising. After regeneration, the impact resistance and aging resistance decreased most, and the breaking strength and elongation decreased.

Polyvinyl chloride

The color change is more obvious after regeneration, and it will be light brown after one re-extrusion extrusion, and almost become opaque brown after three times. The specific viscosity does not change at the second time, and there is a tendency to decrease more than twice. Whether it is hard or soft polyvinyl chloride, stabilizers should be added during regeneration. In order to make the reworked product luster, the amount of blending which can be added during recycling is generally 1-3%.