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Parsing polyurethane board characteristics and selection
Polyurethane panel has following features:
Stability: light weight, high strength, good dimensional stability.We produce batch sheet, rigid polyurethane foam slaking foam performance tests after a week, foam performance.
Strong adhesive force: polyurethane rigid foam for steel, aluminum, stainless steel, such as metal, wood, concrete, asbestos, asphalt, paper, and most of the plastic material such as polyethylene, polypropylene has good bonding strength.Foam material and the bonding strength between directly affects the size of the practical effect of composite plate.
Adiabatic superior performance: polyurethane hard foam obturator rate is high, the coefficient of thermal conductivity is extremely low, so the polyurethane hard foam thermal insulation performance is good in the current building materials.Polyurethane (pu) sandwich panels, according to data than not heat preservation and heat insulation of exterior wall save 60% homework after heating fee to steel plate with rigid polyurethane foam plastics compound as an example, the thermal conductivity of the composite plate are listed in.
The choice of polyurethane plate raw 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 polyol, 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 dosage can be within 1.5 ~ 2.5 (mass fraction) to adjust the types of foaming agent, dosage of polyurethane rigid foam density, strength and other physical properties have 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 CFC fluorinated hydrocarbons seriously ecological environment destruction, 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.
