Wood-plastic composite materials often need to add lubricants to improve the fluidity of the melt and the surface quality of extruded products. The lubricants used are divided into internal lubricants and external lubricants. The choice of internal lubricant is related to the matrix resin used. It must have good compatibility with the resin at high temperature, and produce a certain plasticizing effect, reduce the cohesive energy between the molecules in the resin, and weaken the interaction between the molecules. friction, in order to achieve the purpose of reducing the melt viscosity of the resin and improving the melt fluidity.
The external lubricant actually plays the role of interface lubrication between the resin and the filler in the plastic molding process, and its main function is to promote the sliding of the resin particles. Usually a lubricant often has both internal and external lubricating properties. Lubricants have a certain influence on the service life of molds, barrels and screws, the production capacity of extruders, the energy consumption in the production process, the surface finish of products and the low temperature impact performance of profiles. Commonly used lubricants are: zinc stearate, ethylene bis-fatty acid amide, polyester wax, stearic acid, lead stearate, polyethylene wax, paraffin, oxidized polyethylene wax factory, etc.
Generally, stearic acid, paraffin, PE wax, calcium stearate, etc. are used to form a wood-plastic lubricant system in the required proportion. Stearic acid and paraffin are cheap and have good lubricating performance. The disadvantage is that the melting point is too low (more than 50 degrees). The low melting point lubricant also acts as a plasticizer while giving lubricity, which affects the rigidity of the product. The high Vicat and low heat distortion temperature make the product easy to deform with the increase of temperature, and it is easy to precipitate and affect the production. If PE wax is produced from new PE material and is 100% pure, the melting point can reach above 80 degrees without reducing the vicat of the product. If the PE wax manufacturer uses recycled PE material and adds a certain proportion of stearic acid and paraffin wax in order to reduce the cost, it will not be the real PE wax, which will also affect the performance of the product.
Leave a message
We’ll get back to you soon