内添加型PET多层共挤光扩散膜的制备与性能研究

发布时间：2018-01-05 02:05

本文关键词：内添加型PET多层共挤光扩散膜的制备与性能研究　出处：《西南科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：光扩散膜是LCD液晶显示器背光源模组中重要的光学薄膜,它常被应用到灯饰广告牌、户外显示屏、液晶显示器中起雾化光源的作用。当前,制备光扩散膜的方法主要有涂布法和共混法,而采用多层共挤方式制备光扩散膜的研究鲜有报道。由于多层共挤光扩散膜具有能解决因涂布不均导致的掉粉、掉渣情况,同时相对于单层光扩散膜,又有减少光扩散剂的使用量,节约生产成本等优势,因此本文对内添加型PET多层共挤光扩散膜进行了相关研究。本文首先制备了LLDPE/PET多层共挤光扩散膜,研究了光扩散剂含量、热拉伸方式、拉伸倍数等对光扩散膜的透光率和雾度的影响,同时采用扫描电子显微镜对PET薄膜脆断面进行了形态研究。结果表明:随着LLDPE含量的增加,分散相平均粒径增大,未拉伸薄膜的透光率降低,雾度升高。经过双轴拉伸后,分散相形态逐渐偏离球形,多层光扩散膜的透光率增加,雾度逐渐降低,但雾度降低趋势小于单层光扩散膜。LLDPE含量占光扩散层8wt%时,制备的多层光扩散膜(177μm)的透光率为87.4%,雾度为84.42%。采用多层共挤制备的LLDPE/PET光扩散膜,在透光率提高的同时,雾度依然保持在较高值,且光扩散剂的用量比单层光扩散薄膜要少50%。其次,制备了有机硅/PET多层共挤光扩散膜,研究了光扩散剂含量、拉伸倍数、螺杆转速比、挤出温度、冷却辊转速和温度、增粘PET等对光扩散膜的透光率和雾度的影响。结果表明:随着双轴拉伸倍数的增加,多层光扩散膜的透光率先增加后减小,雾度先减小后增加。当拉伸倍数过大时,薄膜表面将形成球冠型微结构,引起透光率降低,雾度升高。同时,提高中间层挤出温度、降低光扩散层与中间层厚度比例、提高冷却辊转速和降低冷却辊温度均会使透光率增加,雾度降低。当有机硅含量占光扩散层10wt%,螺杆转速比为110:80,冷辊温度为25℃,冷辊转速为1.4m/min时,经双轴拉伸2.5倍的有机硅/PET多层光扩散膜(160μm)的透光率为81.2%,雾度为93.24%。光扩散层中的PET经1wt%扩链剂增粘后,主挤出机的螺杆转速可调节范围更宽广,更有利于多层共挤光扩散膜的制备成型。再次,制备了PP/PET多层共挤光扩散膜,研究了光扩散剂含量和粒径、相容剂含量、拉伸倍数等对光扩散膜的透光率和雾度的影响。结果表明:通过添加2.5wt%PP-g-MAH,能够有效的改善PET树脂与分散相的相容性,细化分散相颗粒尺寸。随着双轴拉伸倍数的增加,光扩散膜的透光率先升高后趋于不变,雾度逐渐降低。当双轴拉伸倍数大于3倍后,分散相颗粒形貌逐渐偏离球形,且其球形度的改变是引起透光率和雾度变化的一大原因。当螺杆转速比为110:80,PP-g-MAH和PP含量占光扩散层12wt%时,经双轴拉伸2倍的PP/PET多层共挤光扩散膜(210μm)的透光率为78.2%,雾度为93.33%。最后,为了将多层共挤光扩散膜与涂布型光扩散膜进行对比,制备了PMMA/PET涂布型光扩散膜。结果表明:随着PMMA含量的增加,透光率减小,雾度增大,当PMMA含量占涂布层23wt%时,薄膜的透光率为90.1%,雾度为87.03%。与采用涂布方式制备的PMMA/PET光扩散膜相比,采用多层共挤方式制备的PP/PET光扩散膜和有机硅/PET光扩散膜的雾度均较高,透光率则略低。
[Abstract]:Light diffusion film optical thin film is an important LCD LCD backlight module, it is often applied to lighting billboards, outdoor displays, play a role in liquid crystal display light source atomization. At present, preparation method of light diffusing film main coating method and blending method, and the way of research is rarely reported in coextrusion layer system preparation of light diffusion film. The multilayer coextrusion light diffusion film can solve due to uneven application of lead powder, dregs, and compared with single-layer light diffusing film, and reduce the use amount of light diffusing agent, saves the production cost and other advantages, so this type of addition of PET multilayer films were light diffusion related research. First LLDPE/PET multilayer light diffusion film prepared in this study, the light diffusing agent content, hot stretching, stretching ratio on the influence of light diffusion film transmittance and haze, while using scanning electron. Micro mirror the morphological study of PET thin film brittle fracture surface. The results showed that with the increase of LLDPE content, the average particle size of dispersed phase increased, transparent unstretched films decreased haze increased. After biaxial tension, the morphology of dispersed phase gradually deviate from spherical, transparent multilayer light diffusing film haze rate increased gradually reduced, but the fog degree decreased less than single light diffusion film.LLDPE content accounted for the light diffusion layer 8wt%, multilayer prepared light diffusing film (177 m) of the 87.4% light transmittance, haze is 84.42%. prepared by multi-layer coextrusion LLDPE/PET light diffusion film, while improving the light transmittance, haze still keep in high value, and the light diffusing agent is less than 50%. the second monolayer film diffusion light, preparation of silicone /PET multilayer light diffusing film of light diffusing agent content, stretching ratio, screw speed, extrusion temperature, cooling roller speed and temperature, viscosity Effect of PET on the light diffusing film transmittance and haze. The results showed that with the increase of biaxial tensile ratio, multilayer transparent light diffusing film first increased and then decreased, haze decreased and then increased. When the stretching ratio is too large, the film surface will form the spherical micro structure caused by transmittance decrease, haze increased. At the same time, improve the middle layer extrusion temperature, reduce the light diffusion layer and the middle layer thickness ratio, improve the cooling roll speed and reduce the cooling roll temperature will cause higher transmittance, haze reduced. When the light diffusion layer of silicone content accounted for 10wt%, the screw speed is 110:80, cold roll temperature is 25. Cold roller speed of 1.4m/min, silicone /PET multilayer biaxial stretching 2.5 times the light diffusion film (160 m) of the 81.2% light transmittance, haze is 93.24%. light diffusion layer in PET by 1wt% chain extender viscosify, main extruder screw speed adjustable range is wider, more A multilayer coextrusion molding preparation for light diffusing film. Thirdly, the preparation of PP/PET multilayer coextrusion light diffusing film on the light diffusion agent content and particle size, the content of compatibilizer, influence of stretching ratio on the light diffusing film transmittance and haze. The results showed that by adding 2.5wt% PP-g-MAH compatible effective improvement of PET resin and dispersed phase, fine particle size of disperse phase. With the increase of biaxial tensile ratio, light diffusion film first increased and then remained unchanged, the haze gradually decreased. When the biaxial tension is greater than a multiple of 3 times, the morphology of dispersed phase particles gradually deviate from spherical, and the spherical degree of change a major cause of transmittance and haze change. When the screw speed ratio of 110:80, PP-g-MAH and PP content of the light diffusion layer 12wt%, the PP/PET multilayer biaxially stretched to 2 times the light diffusion film (210 m) of the 78.2% light transmittance, haze is 93.33 In order to%. Finally, the light diffusion film and multilayer coextrusion coating type light diffusion film were compared, PMMA/PET coated optical diffusion membrane was prepared. The results showed that with the increase of PMMA content, the transmittance decreases, the fog degree increases, when the content of PMMA for coating layer 23wt%, the transmittance of the films was 90.1%, compared to the fog the degree of 87.03%. and PMMA/PET were prepared by coating the light diffusion film prepared by multi-layer coextrusion PP/PET light diffusion film and silicon /PET light diffusing film haze were higher, the transmittance is slightly lower.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.2

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