The Preparation Of Rigid Polyurethane Foam And Study On Its Reinforcement Of Long Fiber Injection

Rigid polyurethane foam, with advantages of light weight, specific strength, good thermal conductivity and easy to combine with other components and simple composite molding, is widely used in construction, transportation, packaging and furniture etc,but using as structure materials, high impact strength and tensile strength and compression strength also be required. Glass fiber is usually used as the reinforced materials for improving the hardness, strength and thermal stability of rigid polyurethane foam; But in traditional process of glass fiber reinforced rigid polyurethane foam, the effect is not good for the limitation of adding amount and length of the glass fiber. Long Fiber Injection (LFI) is a kind of process of polyurethane molding technology with rapid development in last few years, the long fiber is together with polyurethane raw materials after being cut into a certain length, so it can not be limited by fiber length and adding amount, the reinforced materials has very good performance.The high-performance rigid polyurethane foam is firstly preparated with water as blowing agent, and reinforced by the long glass fiber in this paper, the influence of the factors in the formula and the process conditions on the performance, and the structure and thermal stability of the rigid polyurethane foam are discussed, and the mechanical properties, cells structure, thermal stability and flame retardant properties of the reinforced foam under the conditions of the different fiber length and content is studied.Through discussing the influence of polyol polyether type, content of the blowing agent water, isocyanate index, silicone oil, catalyst etc on the performance of rigid polyurethane foam, the best proportion of RPUF is composed by polyol polyether 4110X 80pbw, polyol polyether YD303 20pbw, water 0.3pbw, silicone oil 1.5pbw, catalyst YT-01 2.5pbw, flame retardant YT-11 4pbw, the isocyanate index for 1.1. The analysis for molding process condition shows that, when the temperature of the polyol polyether, isocyanate and mould for 37℃, 45℃and 50℃respectively, the foam products has the best performance.The density, tensile properties, flexural strength and impact performance of LFI-RPUF composites increases with the content of long glass fiber increaseing; Long fiber influences the cells structure, the cells between long glass fiber and PRUF interface attaches is deformed, and disappears in the area of glass fiber gathered; Glass fiber can be scattered into monofilament, small beam and big bundle of fiber under the affect of the air; Glass fiber and RPUF have relatively strong caking action; Long glass fiber is helpful to improve the thermal stability of Composite; As the content of long glass fiber increasing, the burning rate decreases, and the oxygen index (OI), smoke density and produce smoke rate increases accordingly.