High-Strength & Lightweight PP Honeycomb Panels for Diverse Applications

Why is the PP honeycomb board with a hollow structure inside stronger than a solid board?

Let’s first talk about the structural characteristics.

When we cut a PP honeycomb panel, its cross-section is not solid, but filled with dense honeycomb-shaped holes. Its upper and lower sides are two flat panels, with ribs perpendicular to the panels in the middle. These gold bars divide the internal space into independent closed units. We are accustomed to calling this structure a honeycomb core, which is called an airlock in the market. In fact, it is to use the least amount of materials to build the most stable support skeleton, which can control costs and ensure sufficient strength.

The design of the PP honeycomb board was not conceived out of thin air, but borrowed from the style of honeycomb. Thin beeswax can support honey that is much heavier than itself, as well as animal bones and plant stems. As long as it balances lightweight and high strength, it is basically a hollow structure. And our PP honeycomb board draws inspiration from this natural logic by replicating it with polypropylene material.

A 20mm thick PP honeycomb board, placed horizontally on a bracket, will only undergo slight elastic deformation on its surface when an adult stands on it, and will not collapse. If we continue to increase the weight to 700-800kg, significant structural yielding will occur, and this load-bearing capacity is better than that of many solid wooden boards and plastics.

Because their stress logic is different, the solid wooden board is subjected to force in a rigid and hard manner, with all weight concentrated at the point of stress. Once it exceeds its limit, it will break directly. But the PP honeycomb board is different. It is a distributed load-bearing system, and when the panel is subjected to pressure, the pressure will be quickly transmitted to the surrounding areas through the middle reinforcement bars. Then each honeycomb unit is equivalent to a miniature force column, and the ribs are responsible for bearing the tensile and compressive forces, converting the vertical load into axial force. At this point, if hundreds of mixed units work together, the pressure at a single point will be dispersed throughout the entire panel, which is its core principle of being both light and strong. But it is a directional load-bearing structure itself, and its lateral impact resistance is not as good as the front, which we need to pay attention to.

Let’s take a look at the production process again.

The PP honeycomb board adopts a continuous extrusion molding process, and the entire process cannot be interrupted. If it is interrupted, defects will appear on the board. After being plasticized by screws, the raw materials enter the mold and are melted to form a honeycomb core layer and upper and lower surfaces in one go. Then, composite and cooling molding are completed simultaneously. The parameter control of each link must be precise. The first is the control of melt flowability. The viscosity of polypropylene is particularly sensitive to temperature, so if the temperature difference slightly exceeds the reasonable range, the extrusion speed will be unstable. The second is the strength control of composite nodes. We use hot melt self-adhesive technology, which does not require additional adhesive, thus perfectly avoiding the problem of delamination caused by moisture and heat in the later stage. The third is the elimination of internal stress. Polypropylene will shrink during the cooling process. If the cooling is uneven, a lot of internal stress will remain inside the board. In this way, if we perform secondary processing such as carving, slotting, bending, etc., in the later stage, the board is prone to warping and deformation. Therefore, we should completely release the internal stress from the beginning in order to meet the requirements of subsequent secondary processing.

The load-bearing capacity of PP honeycomb board is not fixed; it is closely related to the thickness of the board, panel thickness, and honeycomb density. We will make different adjustments according to different application scenarios. For example, for the PP honeycomb board used in building templates, we will thicken the panel to improve honeycomb density, ensure load-bearing, and wear resistance. But if it is used in packaging boxes, we will achieve lightweight while meeting the strength requirements, helping everyone reduce transportation costs.

The Conclusion

When we make PP honeycomb sheets, the core is to control the process well, improve the stability of the product, ensure that every batch of goods can meet everyone’s needs, and win everyone’s trust with the quality of the product. We also welcome everyone to visit our factory and observe our production process directly. If you have many questions, you will understand them at a glance.