What Are the Differences Between the 3 Types of PVC Foam Boards?

The naming of these three types of PVC foam boards is derived from their manufacturing technique. In the previous blog, we shared the manufacturing process of PVC foam board. We can know that PVC foam board is made of PVC resin mixed with other auxiliary materials, foamed, and then extruded through the mouth die and shaped into a board. So, what are the specific differences between the manufacturing processes of pvc free foam board, pvc celuka board and pvc co-extruded board?

After the PVC raw material melt leaves the mouth die, it continues to expand freely to a certain distance under the action of the foaming agent, and is shaped into a board by shaping dies. The PVC foam board produced by the free foaming process has a thinner skin, and the density of the inner core and outer layers is about the same.

The opposite of the free foaming process is controlled foaming process. Controlled foaming means that the PVC raw material melt is rapidly cooled as soon as it leaves the mouth die, preventing the surface of the PVC foam board from continuing to foam. The cooling methods include water cooling and oil cooling. The celuka process belongs to controlled foaming process. The PVC celuka board has a harder skin, and the density of the outer layer is greater than that of the inner core.

The co-extrusion process also belongs to controlled foaming process. The production equipment of PVC co-extruded board is different from that of PVC free foam board and PVC celuka board. The production equipment of PVC co-extruded board has more than one raw material barrel, but two. One of the barrels provides the raw material for the inner core and the other provides the raw material for the two surfaces. The PVC raw material melt enters the mold from two raw material barrels at the same time and extrudes to form the surface layer, inner core and bottom layer of the board respectively. The PVC foam board produced by the co-extrusion process has a relatively obvious three-layer structure. The top and bottom layers are not foamed, so the PVC co-extruded board has a harder outer layer.