SBIR Phase I: Die Design Software for Polymer Coextrusion Including Layer Rearrangement Due to Viscous Encapsulation and Secondary Flow

这个小企业创新研究（SBIR）第一阶段项目旨在开发用于精确模拟聚合物共挤出的软件。在共挤出过程中，不同的聚合物通过单个模具同时挤出。共挤塑料部件将几种聚合物的功能和优点联合收割机结合到一个多功能产品中。由于聚合物层在它们流过模头时重新分布，因此难以控制共挤出产品中的聚合物分布。尽管软件的使用对于优化工艺至关重要，但塑料工业中的模具设计人员很少使用商业共挤出软件，因为这些软件包无法模拟复杂共挤出模具几何形状中的多层流动，也无法捕捉聚合物的复杂材料行为。一个独特的算法，称为网格划分技术，这将在新的共挤出软件中使用，将允许模拟任何复杂的共挤出系统。将使用粘弹性方程来模拟共挤出。在共挤出模拟中加入粘弹性效应对于准确地捕捉聚合物层的重排是重要的，因为不同的聚合物在共挤出模头中一起流动。将使用文献中的实验数据验证软件的准确性。将进行新的实验，以确定在共挤出过程中聚合物层重排背后的机制。该项目的商业潜力是完全消除目前用于设计共挤出系统的试错方法，这将使共挤出产品的上市时间缩短30%以上。塑料行业的许多不同类型的公司，包括材料供应商，塑料零件制造商和模具制造商，将能够使用该软件降低成本并增加收入。该软件将在该项目中开发，还将提高对各种复杂性背后的根本原因的科学理解，例如粘性较低的聚合物对较高粘度聚合物的封装，以及共挤出过程中相邻聚合物层之间界面的不稳定性。尽管在共挤出中经常观察到这种复杂性，但这些复杂现象背后的驱动机制仍然没有完全理解。

This Small Business Innovation Research (SBIR) Phase I project aims to develop software for an accurate simulation of polymer co-extrusion. During co-extrusion, different polymers are extruded simultaneously through a single die. Coextruded plastic parts combine the functionalities and benefits of several polymers into a single multi-functional product. Since the polymer layers get redistributed as they flow through a die, control of polymer distribution in coextruded products is difficult. Even though use of software is critical for optimizing the process, die designers in plastic industry rarely use commercial co-extrusion software because these packages cannot simulate multilayer flow in complicated co-extrusion die geometries, and also fail to capture complex material behavior of polymers. A unique algorithm, called mesh partitioning technique, which will be employed in the new co-extrusion software, will allow simulation of any complex co-extrusion system. A viscoelastic equation will be used to simulate co-extrusion. Incorporation of viscoelastic effects in co-extrusion simulation is important to accurately capture the rearrangement of polymer layers as different polymers flow together in a co-extrusion die. Accuracy of the software will be verified using the experimental data in the literature. New experiments will be conducted to identify the mechanism behind polymer layer rearrangement during co-extrusion. The commercial potential of this project is complete elimination of the trial-and-error approach currently being used to design co-extrusion systems, which will cut the time-to-market of coextruded products by over 30%. Many different types of companies in plastic industry, including material suppliers, plastic part manufacturers and die manufacturers, will be able to cut cost and increase revenues using this software. The software, which will be developed in this project, will also enhance the scientific understanding of the root cause behind various complexities, such as encapsulation of higher viscosity polymer by less viscous polymer, and instability of the interface between adjacent polymer layers during co-extrusion. Even though such complexities are commonly observed in co-extrusion, the driving mechanisms behind these complex phenomena are still not understood completely.