基于微注塑成型技术的PLA微针最佳成型工艺研究及其使用性能分析

Analysis of optimal molding process for PLA microneedle based on micro injection molding technology

为了提高聚合物微针的生产效率,提高成型质量,降低生产成本及适应大批量生产的要求,利用微注塑成型技术制备聚乳酸材料(PLA)的医美用微针贴片。通过正交实验法探究了注塑成型过程中的熔体温度、模具温度、注射速度、保压压力以及保压时间五项工艺参数对PLA微针顶端直径的影响。利用电子显微镜及测力计对PLA最佳工艺微针进行形貌尺寸表征及力学强度测试,并进行了体外皮肤穿刺测试及透皮渗透实验验证了其对皮肤的穿刺及渗透作用。结果表明,当工艺参数为熔体温度200℃、模具温度45℃、注射速度360 mm/s、保压压力50 MPa、保压时间4 s时,达到注塑成型PLA微针的最小顶端直径及成型效果,高度达到0.524 mm,顶端直径达到0.027 mm,针尖成型明显最优,且微针达到性能要求。

In order to improve the production efficiency of polymer microneedles and molding quality,reduce the production cost,and meet the requirement of mass production,a micro injection molding technology was used to prepare the poly(lactic acid)(PLA)-based medical and aesthetic microneedle patches.The effects of melt temperature,mold temperature,injection speed,holding pressure,and holding time on the tip diameter of the resultant PLA-based microneedles were investigated by an orthogonal experiment,and their morphology,size and mechanical strength were characterized by electron microscopy and dynamometry.Moreover,the skin penetration and penetration experiments in vitro were carried out to verify the penetration and penetration effects of the PLA microneedles.The results indicated that the injection-molded PLA microneedles obtained a good molding effect with a minimum tip diameter when the process parameters were set to a melt temperature of 200℃,a mold temperature of 45℃,an injection speed of 360 mm/s,a holding pressure of 50 MPa,and a holding time of 4 s.Under such a condition,the PLA microneedles achieved a height of 0.524 mm and a tip diameter of 0.027 mm.The needle tip molding was obviously optimal,and the developed microneedles could meet a requirement of performance.