🐸👑♻️ Moisture in Plastics – A Key Issue in Processing You Cannot Ignore
Moisture in plastics is one of the most significant factors impacting the quality of finished products, production efficiency, and the reduction of material waste. Air bubbles, material brittleness, color changes, or decreased mechanical strength are just some of the issues resulting from poor moisture management. Every processing plant must tackle this challenge. Plastics can absorb moisture from the environment or retain it within their material structure. Improper preparation of raw materials leads to waste, defects, and increased production costs.
Moisture in Plastics – Hygroscopic vs. Hydrophobic
Plastics can be divided into hygroscopic and hydrophobic types, depending on their reaction to moisture.
Hygroscopic plastics: PET, PA, PC, PBT, ABS, SAN, PMMA, PLA, TPU, EVA, PSU, PEI, PETG – absorb moisture from the environment, which can lead to changes in their chemical and mechanical properties. Even when stored under seemingly dry conditions, their structure absorbs water molecules, causing issues during processing.
Hydrophobic plastics: PE (including HDPE, LDPE, UHMWPE), PP (including PP-R), PS (including HIPS), PVC, PVDF, PTFE – do not absorb moisture to the same extent, but surface moisture can still affect their processing. Understanding these differences is critical when planning drying processes and managing the moisture content of raw materials.
Problems Caused by Moisture in Plastics
Excess moisture in plastics can lead to a variety of issues that directly impact production.
Defects in finished products
Air bubbles occur when moisture evaporates during processing, weakening the product's structure and potentially causing damage.
Color changes result from chemical reactions triggered by moisture, causing transparent or colored products to lose their desired appearance.
Brittleness is a common outcome of improper drying, reducing the mechanical strength of finished products.
Increased production costs
Moisture in raw materials generates additional waste. Some materials may become unusable, increasing the cost per unit of production. In extreme cases, defects are only detected after production is complete, leading to the rejection of entire batches of products.
Disruptions in the production process
Excess moisture also affects the performance of injection molding machines and extruders. Water vapor can accumulate in the machinery, causing malfunctions. Production downtime due to these issues generates additional operating costs.
Customer dissatisfaction
Low-quality products lead to complaints and, in extreme cases, the loss of key clients. For example, a producer of food packaging films who delivers defective products may face significant contract penalties and lose valuable business.
Example: Problems with PA in Barrier Film Production
Polyamide (PA) is commonly used as a barrier layer in films, especially in food packaging. Due to its hygroscopic nature, it absorbs moisture from the environment, which can cause significant problems during extrusion. A producer who does not monitor PA moisture levels may encounter defects such as reduced film strength, brittleness, or air bubbles. Some producers attempt to resolve these issues by increasing the temperature on the extruder. However, this often leads to material degradation, higher energy costs, and persistent defects in the finished product.
Is Increasing the Temperature the Solution?
Raising the temperature does not solve the problem of moisture in plastics. On the contrary, it can cause more harm than good. Effective moisture management requires proper drying methods and tools that ensure precise control of moisture levels in raw materials.
What Steps Should Be Taken to Effectively Manage Moisture?
Managing moisture in plastics requires a comprehensive approach, including both the measurement of raw material moisture levels and the implementation of proper practices in production processes.
Training 1: Introduction to Moisture in Plastics
This training provides a solid foundation for those seeking to understand what moisture is and how to measure it. Topics include the basics of moisture testing, how to operate a moisture meter, and ISO standards for measuring the moisture content of plastics.
Training 2: Online Course: Moisture in Plastics - Understand and Solve the Problems
This advanced training focuses on troubleshooting moisture-related issues and implementing practical solutions. Participants will learn how to properly dry plastics, avoid defects such as air bubbles and color changes, and apply best practices to minimize material waste.
Why Attend Both Trainings?
Participating in both trainings allows you to fully understand the issue of moisture in plastics and effectively manage this critical aspect of production. Training 1 provides the theoretical and technical foundations, while Training 2 translates that knowledge into practical solutions and process optimization.
👉 [Sign up for the training "Introduction to Moisture in Plastics" here]
👉 [Sign up for the training "Online Course: Moisture in Plastics - Understand and Solve the Problems" here]