双螺杆挤出机共混改性工艺对高温尼龙基LED支架材料填料硅灰石分散的影响及改善  

Impacts and Improvements of Twin-screw Extruder Co-extrusion Processes on the Wollastonite Dispersions in the High-temperature Nylon-Based LED Support Materials

作　　者：王亚溪 赵智源 黄国栋 WANG Yaxi;ZHAO Zhiyuan;HUANG Guodong(Enterprise Technology Center of Kingfa Technology Co.,Ltd.,Guangzhou 510520,China)

机构地区：[1]金发科技股份有限公司企业技术中心,广东广州510520

出　　处：《塑料工业》2024年第10期157-162,共6页China Plastics Industry

摘　　要：为了解决高温尼龙(PPA)基发光二极管(LED)支架材料共混改性过程中出现的力学性能偏低及注塑成型过程中频繁堵塞进胶口导致成型制件缺胶的问题,研究了双螺杆挤出机螺杆组合、双螺杆侧喂机关键尺寸参数对产品力学性能和硅灰石分散性的影响,同时研究了产品中是否含有硅灰石团聚体对注塑成型过程的影响,并分析其原因。结果表明,使用偏心结构的三头啮合块分散混合硅灰石和使用低外内径比、与主机螺杆间隙大的双螺杆侧喂机喂送硅灰石,均会造成硅灰石在共混改性过程中承受机械挤压形成团聚体,使产品拉伸强度由79.9 MPa下降至最低52.2 MPa,弯曲强度由147.1 MPa下降至最低105.6 MPa,并造成产品在注塑成型过程中频繁堵进胶口,使注塑成型缺胶率大幅上升的严重异常。而在共混改性过程中,使用双头啮合块替换偏心结构的三头啮合块分散混合硅灰石,并使用喂料能力更强的双螺杆侧喂机(高外内径比,与主机螺杆间隙更小)喂送硅灰石,可以有效解决该产品因硅灰石团聚导致的力学性能偏低和注塑成型频繁缺胶的问题。To solve the problems of low mechanical properties and frequent nozzle blockage leading to insufficient glue in the injection molded parts of high-temperature nylon(PPA)-based luminous diode(LED)support materials during the blending modification processes,the effects of the screw combinations and the key dimensional parameters of the twin-screw side feeder on the mechanical properties and dispersion of wollastonite were studied.The impacts of the presence of wollastonite aggregates in the products on the injection molding process were also investigated and analyzed.The results indicate that using an eccentric structure three-head meshing block to disperse and mix wollastonite and using a twin-screw side feeder with a low outer-inner diameter ratio and larger clearance with the main screw to feed wollastonite would cause the formations of wollastonite aggregates under mechanical extrusion pressure during the blending modification process,resulting to a decrease of product tensile strength from 79.9 MPa to the minimum of 52.2 MPa and a decrease of bending strength from 147.1 MPa to the minimum of 105.6 MPa.This also leads to a significant increase in nozzle blockages during the injection molding process,causing a severe abnormal rise in the rate of insufficient glue in the molded parts.However,replacing the eccentric structure three-head meshing block with a twin-head meshing block to disperse and mix wollastonite and using a more powerful feeding twin-screw side feeder(higher outer-inner diameter ratio and smaller clearance with the main screw)to feed wollastonite could effectively solve the problems of low mechanical properties caused by wollastonite aggregations and frequent glue insufficiency during the injection molding process.

关 键 词：双螺杆挤出 高温尼龙 发光二极管支架材料 硅灰石 共混改性 注塑成型 缺胶率 

分 类 号：TQ327.8[化学工程—合成树脂塑料工业]