Is HDPE pipe UV resistant?

We all know that HDPE pipes have a lot of advantages, but there is also another special point that many people many concern about, that is, whether HDPE pipe is UV resistant? HDPE can not resist UV by itself, the function of UV resistant need the help of black colorant or light stabilizer. Only by the addition of these materials, HDPE pipe can achieve the result of UV resistance.

Definition of HDPE pipe

The HDPE tube is also called a high-density polyethylene tube, and "HDPE" is its abbreviation. The HDPE tube is constructed of a denser polyethylene that is typically used to make drains due to its rigidity and unique crystal structure. The high crystallinity of HDPE, that is, the proportion of its crystalline region is large, and thus has a high melting point.

At the same time, HDPE is a thermoplastic resin that has the properties of heat softening, cooling hardening, and maintains this performance regardless of how many times heating and cooling are repeated. The appearance of HDPE is milky white, showing a certain degree of translucency in its cross section.

The function of UV resistance

First, we must recognize that HDPE pipes have a certain UV resistance, and many national and international standards specify the ability to test the resistance of pipes to UV. Typically, these requirements stipulate that pipes that are stored outdoors in a temperate climate for one or two years and that are exposed to solar radiation without affecting their performance are UV resistant.

The natural color of HDPE is white translucent. The milk jugs we use in our daily lives are made of HDPE, but their shelf life is very short, but for milk storage, their shelf life is sufficient because milk is one of the perishable foods. We can imagine that the milk jug should be exposed to the sun for a few months, so the milk jug does not need gravity test, just need a hand to press it, it will be broken.

However, the milk jug test does not indicate that HDPE has no UV resistance. In the process of producing HDPE pipes, we can add colorants. Small pieces of colorant prevent harmful UV rays from penetrating into the plastic. Usually we use carbon black colorants because carbon black is effective in preventing ultraviolet rays in the sun, which is the most effective barrier to UV protection. The use of carbon black colorants provides additional long-term protection for pipelines above ground, where pipes are known to be exposed to UV light.

If you can't add a black colorant, you should choose to add a light stabilizer to absorb light and reduce the harmful chemical reactions caused by ultraviolet light. The light stabilizer has the same function with black colorant.

Tips:Notes on colorant

When colorant is applied to plastic coloring, it can not only make the product look beautiful, but also become the nucleating agent of crystalline plastics (such as HDPE), causing different degrees of shrinkage and warpage of the product. This can not guarantee the same size of all products for the production of high precision plastic products, so when it is necessary to assemble plastic products. When these small shrinkage may cause larger problems, such as threaded bottle cap commodities and so on, especially some varieties of organic pigments play a great role in the shrinkage.

Any additive, including colouring agent, will have an effect on the modification of plastics, especially in modified reinforced plastics. Normally, no matter what pigments are used, the dimensional stability of components must be guaranteed. But considering the diversity of colors, it is impossible for all pigments to meet the above requirements, so sometimes it is difficult to perfect.

EAGLE Company specializes in the development and manufacture of HDPE profiles, tanks and related articles with proven technology and core equipment. If you have a need on HDPE, please contact us in time, we will try our best to provide you with a satisfactory service to meet your existing needs.