The choice of polyurethane sheet materials

Isocyanate ( PAPI） Component selection of yantai wanhua PM - 200, the components are fixed. With the increase of dosage of PAPI, the crosslinking density of foam increases, the strength and stiffness increases, but if excessive dosage of PAPI, bubble will be brittle, core material is easy to crack. First choose polyether polyols, the most important polyether polyol is one of the composition foundation of rigid polyurethane raw material, which affect the physical and mechanical properties of foam core material, dimension stability and foaming process performance. According to the starting dose, hydroxyl value and viscosity of polyether type, with potassium ion content in polyether choose low. It is advisable to select emulsifying ability foam stabilizer. It mainly controls the bubble hole size, maintain the stability of the bubble hole, prevent bubble hole collapse. Organic silicone foam stabilizer has good effect, its usage can be in 1. 5 ~ 2. 5 ( The mass fraction) Regulate the kinds, dosage of foaming agent of polyurethane hard foam density, strength and other physical performance has a direct impact. Foaming agent not only can adjust and control the density of foam products and performance, can also lower the viscosity of the composite polyether, improve its foaming process, the liquidity bubble, bubble forming. Considering the need of sustainable development strategy, now has restricted use of damage to the ecological environment seriously CFC11 fluorinated hydrocarbons, using alternative foaming agent. Choose catalyst can choose delay system, make opal time and gel time interval for a long time, effectively improve the liquidity of foaming system, improve the foam performance, to suit production process operation. Foam inside the cavity is uniform, the fine degree, rate of closed-cell foam height on the plate overall heat preservation performance has a great influence, these factors related to the bubble and the degree of the firm bonding of the cavity wall, the bubble size stability, etc. Flame retardants can improve the fire resistance of foam plastic, but the flame retardants in the foaming process of foam has the damage, on the premise of ensuring better flame retardant effect, ensure the use of plastic foam performance and dimensional stability.