We got an inquiry from European customer that they want to buy HDPE manhole covers yesterday. We wonder why customers still want to buy this type of manhole covers. HDPE manhole covers was a product of elimination in China a few years ago. Now,let’s help you to know more about HDPE manhole covers.
1.What are the specific material is HDPE manhole covers ? How molding ?
HDPE is a high -density polyethylene , which is a thermoplastic polymer plastic widely used as plastic sheeting , plastic bags and other plastic products . All the material for producing HDPE MANHOLE COVERS are from recycled HDPE plastics.The more worse thing is that the factories of HDPE manhole covers like to use poor recycled HDPE plastics in order to reduce the production cost. HDPE plastic material with a polymer at about 140 ~ 160 ℃ under hot temperature conditions, added with large quantities of fly ash (HDPE: fly ash = 30 to 40:60 to 70 ) were kneaded and added steel, steel pressing, then made into manhole covers.
2 . Why do HDPE manhole covers exist in now market?
HDPE material is very cheap because it’s low-grade recycled materials.Currently, a large number of individual Chinese companies and manufacturers purchase HDPE recycled materials at very cheap price to produce new HDPE recycle material,then sold HDPE recycled material at price general from usd300 to usd550/ton. The fly ash with cheaper price usd15 to usd30/ton is mixed into the HDPE covers. some companies have joined the steel skeleton also dismantled the old building made of scrap steel , so this type of manhole covers in the current market is very cheap.
3. HDPE covers have big disadvantages!
HDPE manhole covers exist two disadvantages: The first is : Since this manhole covers use thermoplastic polymer material as a base material,it has a low softening point. In the summer,when the temperature is 38 ℃ , the temperature of HDPE manhole covers will be up to more than 60 ℃. Together with the vehicle on which the friction heat, the carrying capacity of whole covers will decrease due to softening , covers intermediate sinking , and finally off to form a hole slightly smaller than the covers . This manhole covers had appeared above situation in Yunnan , Jiangxi, Guangxi, Tianjin, Hubei and Jiangsu provinces,china occur a large number of security incidents. The second is : HDPE manhole covers with incorporation of a large number of fly ash are of very bad load ability because there isn’t any other reinforcing materials in it except of adding steel reinforcement to increase strength. According to the industry standard of Chinese Renewable resin covers,it’s not qualified manhole covers.