The Study Of The Preparation Of Polymer Particles/ PET Composite Light Reflective Film By Stretching Into Pores

Light reflective film is an important component of liquid crystal display backlight(LCD), playing an extremely important role in the(LCD). Firstly, according to the concept of solubility parameters, ten kinds of typical polymers which have different solubility parameter with PET were selected as the fillers.The fillers were added into the PET matrix, granulating and filming by drooling. The film was biaxially stretched under certain conditions(such as temperature, draw ratio, etc.) is biaxially stretched, obtaining the light reflection film with pores inside. The light reflection performance and the changes between internal and external structure were determined.To choose a light reflective particle with better performance. The preparation process and properties of the polymer particles/PET thin film were studied to get the best process and formula combined with the UV- visible- near infrared spectrophotometer,SEM,optical lens, thermal gravimetric analysis,universal mechanical testing machine.the mechanism of the reflection properties produced by the pore structure of polymer particles/PET film was simply discussed.In the experimental section, the mechanism of the increasing reflectivity of the thin film was preliminary studied, and the best reflective particle was selected from the ten. Experimental results show that: the main factors affecting the reflectivity of the film after stretching is the difference of the solubility parameter. When the difference of solubility parameter between the polymer particle and PET is 1.6-9.2(J/m-3) 1/2, the reflectivity of the film increases with the increasing of the solubility parameter difference. Pore structure formed by the film stretching is beneficial to improve the reflective properties of the film. PP and TPX are the reflective particles which are suitable for forming pore structure by film stretching.Subsequently, TPX was selected as the internal reflective particles in the film. The effect of the the amount of TPX, stretching ratio and stretching temperature on the reflective properties and mechanical properties of the film was investigated and the factor to limit the increase of the of the reflective properties of the film was also discussed. The results showed that the reflectivity of the TPX / PET stretch film was enhanced with the increase of the added amount of TPX, but was limited by the degradation temperature. While the tensile strength was decreased with increaing amount of TPX. 2.5 * 2.5 stretching ratio is the best for the reflectivity of the film. the higher the reflectance, the lower the stretching temperature,the higher the reflective performance and the tensile strength of the film. Under the optimum processing conditions, total reflectivity of TPX / PET film is 80.04%.Finally, PP was selected as the internal reflective particles in the film. The influence of the PP melt index, the amount, stretching ratio and stretching temperature on the reflective properties and mechanical properties of the film was studied and the restrictions condition of the increase of the reflective properties was also discussed. The results showed that the reflectivity of the PP / PET film was improved with the increasing amount of PP particles, but was limited by the high temperature degradation, the tensile strength was reduced gradually with the increasing PP particles. 3*3 stretching ratio was the best for the reflectivity of the film. The lower the stretching temperature,the higher the reflective performance and the tensile strength of the film. The adding of PP-g-MAN is negative for improving the reflecticity of stretched PP / PET film. Under the optimum processing conditions, the total reflectivity of PP / PET film could reach 90.58%.