Inline-Characterization of Bead Foam Extrusion Processing

与现有的可膨胀聚苯乙烯（EPS）和可膨胀聚丙烯（EPP）的代表不同，大多数新的泡沫泡沫不是通过悬浮或高压灭菌工艺生产的，而是通过泡沫挤压和水下造粒的方法连续生产的。这使得添加添加剂更容易。特别是在研究和工业中使用化学改性（例如，CE =扩链剂）来增加技术热塑性塑料的熔体强度，这种强度通常太低而无法发泡。除了灵活性之外，众多的参数也增加了复杂性。此外，在与CE的熔体加工过程中会发生反应过程，从而不断发生显著的材料性能变化。当处理大配方或热敏性材料时，对某些最终性能的控制同样复杂。来自系统和外围的大量数据已经被用于监控；但是，没有进行长期、系统的记录和评价。此外，对工艺进行科学评价所必需的某些值是必要的，但有时根本没有记录或只是部分记录（例如，熔体粘度，泡沫珠的尺寸分布）。数量和质量都可以通过适当的内联分析来提高。附加组件是必要的(i)实时收集所有科学和技术相关数据，（ii）在运行过程中使用合适的数字方法实时评估这些数据。这尤其包括最终产品的特性。理想情况下，可以识别以前未见过的工艺和材料参数之间的关系（例如，反应性，流变性和膨胀的相关性）。此外，还可以创建一个数据基础，通过使用主动学习或机器学习来实现系统的自我优化。通过建模，进一步推动理解和预测未知材料的行为。分析的质量也得到了提高，从在线流变学中可以明显看出：在这里，与离线测量（板-板）相比，测量了与过程相关的（更高的）剪切速率，并且在制备和测量过程中不再需要重复熔化，特别是在化学改性和热敏样品的情况下，这一点至关重要。该系统概念只包含允许数字交换和记录和保存以前丢失的测量变量的组件。材料的变化可以根据压力、流动行为、粒度（分布）和工艺影响进行追踪。因此，需要一个内联流变仪、额外的压力传感器、一个颗粒分析仪和合适的数字外设。

Unlike the established representatives of expandable polystyrene (EPS) and expandedPolypropylene (EPP) most new bead foams are not produced by suspension or in an autoclave process, but continuously by means of foam extrusion coupled to anunderwater granulation. This makes it easier to add additives. Especially thechemical modification (e.g., CE = chain extender) is used in research and industry to increase the melt strength of technical thermoplastics, which is often too low for foaming. In addition to the flexibility, the many parameters also increase the complexity. Furthermore, during the melt processing with the CE reactive processes occur and thus constantly significant material property change. The control of certain final properties is similarly complex when large formulations or thermally sensitive materials are processed. A lot of data from the system and the periphery is already being captured for surveillance; a permanent, systematic recording and evaluation however, does not take place. Furthermore, certain values which are necessary for a scientific evaluation of the process are necessary, but sometimes are not at all or only partially recorded (e.g., melt viscosity, size distribution of the foamed beads). Both quantity and quality can also be increased with appropriate inline analytics.The add-on is necessary (i) to collect all scientifically and technically relevant data in real time and (ii) to evaluate this data - with suitable digital methods - already in real time during the running process. This includes in particular the properties of the final products. Ideally, previously unseen relationships between process and material parameters can be recognized (e.g., correlation of reactivity, rheology and expansion). In addition, a data basis can be created which allows self-optimization of the system through the use of activelearning or machine learning. Through modelling further impulses for understanding and forecasting the behavior of unknown materials are expected. The quality of the analysis is also improved, as becomes evident from the inline rheology is: here, process-relevant (higher) shear rates are measured compared with offline measurement (plate-plate) and the repeated melting during preparation and measurement is no longer necessary, what is critical especially in the case of chemically modified and thermally sensitive samples. The system concept exclusively contains components that allows a digital exchange andrecord and save previously missing measured variables. Material changes can be traced based on pressures, flow behavior and particle sizes (distribution) and process influences. Therefor, an inline rheometer, additional pressure sensors, a particle analyzer and suitable digital peripherals are required.