Discussion on SPC Floor and WPC Floor Formula Extrusion Process and Problems

Since the outbreak of the “poisonous floor” incident in the United States, the United States has continuously raised the threshold for wood products imports in recent years. However, WPC, a plastic floor that came into being, combines the waterproofness and stability of LVT, and the foot feel and sound insulation effect will be more comfortable than the lock floor of LVT. The American magazine “floorcovering NEWS” made no secret of the praise of WPC WPC flooring. In the July 2017 issue, it introduced the past and present life of WPC WPC flooring and the latest fashion trends, and pointed out that WPC WPC flooring will Win a new round of development opportunities. The magazine also mentions that the latest SPC (Stone plastic compostic) stone plastic flooring, also called RVP (Rigid vinyl Plank), is a new environmentally friendly flooring developed based on high technology. It has zero formaldehyde, mildew, moisture, fire, and insect resistance. Features such as simple installation have gradually become the new darlings of European and American markets.

The main differences between SPC and WPC floors are:

SPC floor is a high-calcium non-foaming product. The density of calcium carbonate is 250-300 parts and the density is 2-2.1. WPC floor is a foam product with a density of 0.85-0.9 and its filling is 80-100 parts. The comparison between SPC and WPC flooring is different. SPC has a high specific gravity of calcium, simple processing procedures, and excellent dimensional stability. WPC floor foam products have high requirements for the extrusion process, and it is difficult to control the shrinkage stress problem.

Brief analysis of common problems-poor product molding

1. The product size is unstable, the mold is not full, and the wall thickness is uneven.

Reasons: The formula is unreasonable for internal and external lubrication, the feeding speed is unstable, the screw barrel is seriously worn, and the coordination gap is incorrect;

Solution: Improve the ratio of internal and external lubricants, correct feeding failure, replace the barrel and screw, and adjust the clearance between the barrel and the screw.

2. The product appearance is uneven, the color difference is obvious, and irregular fish scales appear on the surface; the product performance is poor; the toughness is poor, the product is brittle, and the impact resistance is unqualified;

Reasons: The formula structure is unreasonable, the inorganic filling is too high, the plasticization is poor, and the amount of impact materials is insufficient;

Solution: Correct the formula structure, appropriately reduce the content of inorganic fillers, modify the plasticization of the material to about 65%, and add impact materials as appropriate. 

3. The output of the finished product is bent, deformed, and locally subsided;

Reason: the head and the die are not on the same plane, the extrusion speed is too fast, the temperature of cold water is too high, the water pressure is too small, the water flow is insufficient, the water and gas path is not smooth, and the vacuum negative pressure is insufficient;

Solution: Correct the die head and the setting die at the same level, reduce the extrusion speed & cooling water temperature, increase the water pressure and flow, and adjust the vacuum negative pressure to check the water and air channels.