改性塑料注塑制品中流痕的成因研究进展  

Advance on Formation of Flow Marks in Modified Plastic Injection Molding Products

作　　者：鲁明 杨波 彭莉 罗忠富 李成 丁超 LU Ming;YANG Bo;PENG Li;LUO Zhongfu;LI Cheng;DING Chao(Kingfa Science and Technology Co.,Ltd.,Guangdong Guangzhou 510663,China)

机构地区：[1]金发科技股份有限公司,广东广州510663

出　　处：《广州化工》2024年第23期15-18,共4页GuangZhou Chemical Industry

摘　　要：流痕是改性塑料注塑制品中一种常见的表面缺陷,其通常表现为明暗相间的、垂直于流动方向分布的条纹。这些条纹状缺陷是聚合物熔体在注塑过程中在狭窄的模腔内流动时形成的,它的形成不仅与材料在模腔内的流动状态相关,也和材料的组成以及流变学特征是紧密相关的。本文介绍了流痕的外观表现及特征,并探讨了两种主流的流痕的成因机理:熔体粘附-滑移机理与熔体前沿不稳定流动机理。熔体粘附-滑移机理认为流痕是注塑过程中熔体在冷模壁上发生粘附状态和滑移状态的交替转换,从而导致制品表面的微观形态差异。而熔体前沿不稳定流动机理认为熔体前端在模腔内呈现为震荡流动状态,在上下模壁之间不断摆动,这种震荡流动导致熔体在模壁上的应力状态差异造成了制品表面的光泽度差异,形成了视觉上的条纹状缺陷。然而,这两种机理仍不能完全解释流痕的各种表现形式,流痕的深层次成因还有待进一步研究。Flow marks are a common surface defect in modified plastic injection molding products,which typically manifest as alternating light and dark stripes distributed perpendicular to the flow direction.These striped defects are formed when the polymer melt flows through the narrow cavity in the injection molding process.Their formation is not only related to the flow state of the material within the mold cavity but is also closely related to the composition of the material and its rheological characteristics.This article introduces the appearance and characteristics of flow marks and discusses two mainstream mechanisms for their formation:the melt stick-slip mechanism and the unstable flow mechanism at the melt front.The melt adhesion-slip mechanism posits that flow marks are the result of alternating stick and slip states of the melt on the cold mold wall during the injection process,leading to differences in the micro-morphology of the product surface.On the other hand,the unstable flow mechanism at the melt front suggests that the melt front exhibits an oscillating flow state within the mold cavity,constantly swinging between the upper and lower mold walls.This oscillating flow leads to differences in stress states on the mold walls,causing variations in the gloss of the product surface and forming visually striped defects.However,these two mechanisms still cannot fully explain the various manifestations of scratch marks,and further research is needed to understand the deeper causes of their formation.

关 键 词：流痕 粘附-滑移 不稳定流动 

分 类 号：TQ320.66[化学工程—合成树脂塑料工业]