PVC foam board has the advantages of chemical corrosion resistance, weather resistance, flame retardancy, etc., and is widely used in many aspects, including display panels, signs, billboards, partitions, construction boards, furniture boards, etc. What will happen if the foaming agent of the PVC foam board is not added properly? Hangzhou Gege PVC boards factory will come to give you detailed answers in this regard.
What is the difference between PVC foam board and wood?
1. The characteristics of waterproof, flame retardant, acid and alkali resistance, mothproof, lightweight, heat preservation, sound insulation, and shock absorption
2. The same processing as wood, and the processing performance is far better than wood
3. It is an ideal substitute for wood, aluminum, and composite panels
4. The surface of the crust board is very smooth, with high hardness, and not easy to scratch. It is often used to make cabinets, furniture, etc.
The production of PVC foam board generally uses three different foaming agents: exothermic type, endothermic type, or endothermic and exothermic composite balanced type. Ammonium azodicarboxylate, also known as AC, is an isolation activator. The decomposition temperature of the AC foaming agent is high, up to 232°C, which is far beyond the processing temperature of PVC, so the decomposition temperature should be lowered during use.
The exothermic foaming agent has a high foaming rate, about 190-260ml/g, and has a fast decomposition speed and great heat release, but the foaming time is short and the burst is also strong. Therefore, when the amount of AC foaming agent is too much, the amount of gas generation is too large, which will cause the internal pressure of the bubble to increase rapidly, the size of the cell will grow too large, and the gas will be released rapidly, which will destroy the cell structure, unevenly distribute the cell size, and even form an opening. The porous structure will generate larger air bubbles and cavities locally.
When producing foamed plastic products, the exothermic foaming agent AC should not be used alone, and should be used in conjunction with the endothermic foaming agent or a compound chemical foaming agent with a balance between heat generation and heat release. The inorganic foaming agent sodium bicarbonate (NaHCO3) is an endothermic foaming agent. Although the foaming rate is low, the foaming time is long. Mixing it with AC foaming agents can play a complementary and balanced role.
The exothermic foaming agent improves the gas-generating capacity of the endothermic foaming agent, and the endothermic foaming agent cools the former, stabilizes its decomposition, and releases gas in a balanced manner, inhibits the overheating degradation inside the thick plate, and reduces the precipitation of residues. Has a whitening effect.