Primary Study On Preparation And Properties Of Halogen-free Flame Retardant Laminate Reinforced By GF/PP Commingled Yarn Fabrics

The fabric reinforced composite is a promising material which can be widely used for structural components.But these composites were easily to burn due to the reinforced fiber.With the increasingly strict requirements of environment,halogen-free flame retardant material was a good application.However,the application of halogen-free flame retardant material in fiber reinforced composites was much more difficult than that of halogen flame retardant material.For example,the content of halogen-free flame retardant is larger.And it had poor thermal stability.One glass fiber / polypropylene(GF/PP)commingled yarn fabric and four PP matrix halogen-free intumescent flame retardant(IFR)masterbatches were used.A novel halogen-free flame retardant laminate reinforced by GF/PP commingled yarn fabrics has been prepared using the laminate molding process.Firstly,the preparation process of the halogen-free flame retardant laminate reinforced by GF/PP commingled yarn fabrics was studied.Two preparation methods including “indirect method” and “direct method” had been used.“Indirect method” – Firstly,GF/PP commingled yarn fabrics were melted and impregnated fully.Then the GF/PP commingled yarn fabric plates and polypropylene halogen-free flame retardant plates were laminated according certain rules of stacking.“Direct method ”-GF/PP commingled yarn fabrics and PP matrix halogen-free flame retardant plates was laminated directly according certain rules of stacking.“Indirect method” can be laminated at lower temperature and for shorter time,which is greatly suitable for IFR system with lower decomposition temperature.While “direct method” that is suitable for IFR system with higher decomposition temperature can be laminated at higher temperature and for longer time.Study showed that stacking rules made a difference on mechanical properties of halogen-free flame retardant laminate reinforced by GF/PP commingled yarn fabrics.The tensile strength of fabric plate which was parallel stacked was up to 154.95 MPa.The flexural strength of laminate in which fabric plate and PP matrix halogen-free flame retardant plate was stacked alternately was up to 174.46 MPa.The notched impact strength of laminate in which the fabric plates were stacked with 45°angle was up to112.15 KJ/m2.It may conclude that the composition,the content of maserbatch and the flame retardant plate thickness had great effect on the flame retardant performance of laminates reinforced by GF/PP commingled yarn fabrics.The masterbatch PP60120 had the best flame retardancy.The laminate can pass V-1whenthe content of masterbatch PP60120 was 30% and the flame retardant plate thickness was 0.6 mm.And the limit oxygen index(LOI)of laminate is up to 41.0%.The flame retardant process of those laminates is that non flame retardant laminate cannot keep sustained combustion when flame retardant plate is quickly decomposed into compact char layer which can insulate heat and oxygen.