Preparation And Properties Of Flame Retardant Anti-dripping EVA Spectrum Conversion Film

Spectrum conversion film is widely used in the fields of agricultural film and photovoltaic film.Exposed to the sun,its possible burning will cause serious economic losses and environmental pollution.Ethylene-vinyl acetate copolymer（EVA）is often selected as the substrate of spectrum conversion film because of its high transmittance and good melt mobility.However,the LOI value of EVA is only about 18%,the flame retardancy is poor,and a serious melt drop phenomenon is evident during combustion.Therefore,it is necessary to carry out flame retardant and anti-dripping modification of EVA spectrum conversion film.In this paper,three different flame retardant and anti-dripping methods are proposed,and two different spectrum conversion agents are synthesized to prepare EVA films.The main contents of this subject are as follows:1.Flame retardant anti-dripping EVA composite films are prepared by solution casting method.The preferred flame retardants are toluene diphenyl phosphate（CDP）and trimethylphenyl phosphate（TCP）.The main component of anti-dripping agents（PT200,AP1000）is polytetrafluoroethylene（PTFE）.The flame retardancy is considered by the LOI and UL-94 vertical tests.Meanwhile,the melting drip is observed and the transmittance curve of the flame retardant EVA film is measured by UV-Vis spectrophotometer.With a 15%halogen-free flame retardant content,UL-94V-0 rating can be achieved and LOI value increase to 30%.The transmittance of flame retardant EVA film in the visible region is the same as that of the pure EVA film,but the melting drip phenomenon is even more serious.When 0.5～1%anti-dripping agent is added,the amount of flame retardant can be reduced by 66.7～86.7%with no melt drips,and the transmittance of the film in visible light region is more than 95%of that of pure EVA film.2.Monomer 5-（benzylidene amino）-dimethyl isophthalate（BA）and hydrolyzed EVA（EVAL）are first synthesized,and then,crosslinked flame retardant anti-dripping EVA composite films are prepared by high temperature self-linking method,in which BA and EVAL are crosslinked at high temperature.The flame retardancy study shows that when the content of BA is 1%and the addition of CDP flame retardant is 5%,the crosslinked EVA film achieves V-0 rating with non-dripping behavior,and LOI value increases to 29.0%.The transmittance of crosslinked films in the visible region is 89%of that of pure EVA films.3.Rare earth europium complex Eu（DBM）₃phen（Eu DP）and aggregation-induced emission agent triphenylacrylonitrile（TPA）are synthesized and used as light conversion agents for EVA film.A series of flame retardant anti-dripping EVA composite spectrum conversion films are respectively prepared by using the above three flame retardant anti-dripping methods.The studies of visible light transmittance and fluorescence properties show that both Eu DP and TPA have good absorption in the UV region.Eu DP can convert ultraviolet light to red light while TPA can convert UV light to blue light,and the transmittance is 90%of that of pure EVA films.Each film can achieve V-0 rating in UL-94 vertical tests.