How to quickly distinguish between new material and recycled material of HDPE carat pipe

Look at the appearance, texture and color

The inner and outer walls of the new material HDPE carat tube are uniform and smooth, and the whole is positive milky white or semi-matte transparent white. There are no variegated spots, depressions, and pores on the surface. The incision is flat and dense, and there is no pungent odor close to the smell. The carat tubes produced by recycled materials are mixed with waste plastic impurities, and the color is generally gray and yellowish. Obvious black spots or color blocks can be seen on the surface of some products. There are uneven defects on the tube wall. There are pores visible to the naked eye at the incision, and some of them also emit pungent plastic odors.

Measurement of weight and hardness differences

HDPE carat pipes with the same specifications and the same ring stiffness requirements have uniform density and stable weight within the error range stipulated by the national standard. Fillers are often added to reduce costs during the production of recycled carat pipes, either the weight is significantly beyond the standard range, or the weight is light due to insufficient raw material compactness. In addition, the surface of the pipe is lightly scraped with hard items. The scratches of the new material carat pipe are shallow, and the scraped debris is uniform and free of impurities. The hardness of the recycled carat pipe is low, and the scratches are deeper. There will also be slag and surface peeling.

Simple combustion test identification

If conditions permit, small pipe samples can be intercepted for combustion testing: when the new material HDPE burns, the flame turns yellow and blue, and there is no obvious black smoke. During the combustion process, it will drop liquid evenly, emitting a light smell similar to paraffin wax. After combustion, the residue is light white or light yellow, and there are no impurity particles. When the return material carat tube burns, it emits strong black smoke, accompanied by a pungent plastic odor. After combustion, the residue is black and gray, and obvious impurity agglomeration can be seen.

Verify performance parameter match

The supplier can be required to provide the corresponding test report when purchasing the project. The ring stiffness, ring flexibility, drop weight impact performance, low temperature embrittlement temperature and other parameters of the new material HDPE carat pipe are stable, fully in line with the requirements of the national standard, and the normal construction service life can reach more than 50 years. The performance parameters of the recycled carat pipe fluctuate greatly, and most of them cannot pass the low temperature impact and ring flexibility test. After being put into use, they are prone to leakage and cracking problems, and the service life is only 1/3 or even shorter of the new material product.

Do not blindly pursue low prices when purchasing models on a daily basis. It is recommended to combine the above methods for comprehensive identification to avoid the entry of inferior pipes, which will lead to later project rework and increased operation and maintenance costs.