More and more producers of LDPE for extrusion coating pass from autoclave production to a tubular production. Tubular types are characterized by very good optical properties but with lower melt strength that is the key property for extrusion coating. For this reason, we began to register a higher demand for the material which compensates reduced melt strength and has a positive effect on other product properties.
In order to ensure higher melt strength (usually for LDPE tubular types), reduction of necking and increase adhesion of the coating and substrate (paper, PE, aluminum and others) in extrusion coatings, we use a special type of Granic® (based on calcium carbonate). With the addition of this material we specifically affect the problematic aspects of materials and production and at the same time we reduce the production costs.
We were contacted by the customer who produces films for roofs because he needed higher strength of the coating and better adhesion of the substrate. The coating was from LDPE and the substrate was net from HDPE. With the addition of special Granic® material we achieved excellent adhesion and thanks to the whiteness of calcium carbonate we reduced dosing of the white masterbatch by 50 %.