Preparation Of Organic Phosphate Halogen-free Flame Retardant Packaging Materials

As a new generation of light source, LED is widely used because of high efficiency, environmental protection, long life etc. LED packaging materials can protect LED from the impact of external conditions. Currently, photoelectric conversion rate of LED is just about 20%, the rest of energy is converted into heat. This part of heat will accelerate the aging of LED lamp and lead to the burning of packaging materials more likely. However, most packaging materials now are flammable. With the development of power type LED lamp and white light LED lamp, and it’s miniaturization and integration, packaging materials has become a bottleneck restricting the development of LED. Therefore, it’s urgent to develop packaging materials with flame retardant properties. There’s a big difference between packaging materials and emitting chip,so we increased the refractive index of packaging materials based on its flame retardant property, this method can not only reduce the probability of occurrence of fire, but also improve the LED light electricity conversion rate. The introduction of sulfur is considered to be the most effective and convenient method.Based on above points, the study first chose 2-hydroxyethyl acrylate(HEA) reacting with phosphorus oxychloride(POCl3) and hexachlorocyclotriphosphazene(HCCP) respectively to obtain organic phosphate with two acrylic structure. Then sulfur element was introduced through click chemistry and free radical reactions to improve the refractive index rate of packaging material.1. One-step method was used to synthesize organic phosphate TAEP, FT-IR and NMR test were appied to prove the synthesized TAEP. PTAEP was obtained by free radical homopolymerization, differential scanning calorimetry(DSC), thermal gravimetric analysis(TGA), scanning electron microscopy(SEM) and vertical burning test were used to test its optical and other related properties.2. TAEP and PETTG were reacted by different proportions, to gain organic phosphate Packaging materials containing different content of phosphorus and sulfur. Experimental results showed that the flame retardant properties of the packaging materials and the refractive index increased with the increase of sulfur content. when the content of sulfur and phosphorus is respectively 2% and 7.37%, the refractive index,flame retardancy and decomposition temperature of 5% are respectively 1.4935,UL-94 V-0 @3.0 mm level and 200.1 ℃。3. Acrylamide(AM) was introduced to the TAEP/PETTG system to get organic-phosphate package materials with sulfur and nitrogen after curing. Experimental results showed that the introduction of nitrogen could form a phosphorus-nitrogen synergistic flame retardant in the packaging material. Under the premise that the guaranteed level of flame retardant was UL-94 V-0 @3.0 mm, the sulfur content in the system could be further improved. When the content of phosphorus, sulfur and nitrogen were respectively 6.70%, 3%, 1%, the refractive index and flame retardant grade were respectively 1.4987 and UL-94 V-0 level.4. Under 60 ℃, HEA and HCCP were used as raw materials to synthesize hexa(2-hydroxyethyl acrylate) cyclotriphosphazene(HACP). The synthesized HACP was proved by FT-IR, 1H NMR and 13 C NMR. The contrast of DSC and TGA curves of HACP with those of TAEP showed that all of them had similar curing process and thermal decomposition process. Because the introduced groups were different, the decomposition temperature of 5% was 63.8℃ higher than that of TAEP. The carbon yield was 1.21% higher than that of TAEP.