Halogen-Free ESD Additive for TPU
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Solution Overview
Problem
Conventional electrostatic dissipative (ESD) materials for plastics face challenges such as degradation of plastics, loss of ESD properties due to high temperatures, non-miscibility with base polymers, and undesirable surface effects, along with the need to reduce halogen content, which limits their effectiveness and longevity.
Innovation Solution
A halogen-free ESD additive system comprising a thermoplastic polyurethane made by reacting polyol intermediates with diisocyanates and chain extenders, combined with a halogen-free metal salt of amidoalkanesulfonic acid or hydrocarbyl-substituted benzenesulfonic acid, providing inherent electrostatic dissipative properties without the drawbacks of traditional ESD agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antistatic agents are incorporated into base polymers, then electrostatic dissipative properties are provided, but the high temperatures required for processing may damage or destroy the antistatic agents
Solution Approach 1:
The invention changes the molecular weight parameter of the ESD agent from low to high (greater than 10,000 Daltons), which fundamentally alters the thermal stability and processing behavior of the additive, allowing it to withstand conventional polymer processing temperatures without degradation
Solution Approach 2:
The invention creates a composite system by combining high molecular weight ESD agents with specific base polymers, forming a unified material composition where the ESD agent and polymer matrix are mutually compatible and can be processed together at elevated temperatures
2Reliability
If lower molecular weight ESD agents are used, then ESD properties are achieved, but they possess undesirable lubricating properties and are difficult to incorporate into the base polymer
Solution Approach 1:
The invention changes the molecular weight parameter from low to high (greater than 10,000 Daltons), which eliminates the lubricating properties and surface migration issues while maintaining ESD effectiveness and improving compatibility with base polymers during processing
3Reliability
If a large number of antistatic agents are used to achieve ESD properties, then electrostatic dissipation is improved, but they cause degradation of plastics, particularly PVC, and result in discoloration or loss of physical properties
Solution Approach 1:
The invention changes the chemical structure and molecular weight of the ESD agents, selecting high molecular weight compounds that are chemically compatible with various plastics including PVC, thereby eliminating degradation, discoloration, and physical property loss while maintaining ESD functionality
Solution Approach 2:
The invention replaces harmful conventional ESD agents with safer high molecular weight alternatives that do not cause plastic degradation, effectively substituting a problematic material with a benign one that achieves the same ESD function without side effects
4Reliability
If lower molecular weight antistatic agents are incorporated into base polymers, then ESD properties are provided, but they can move to the surface of the plastic during processing and frequently deposit a coating on the surface of the molds
Solution Approach 1:
The invention changes the molecular weight parameter to greater than 10,000 Daltons, which prevents surface migration and mold coating during processing, thereby maintaining smooth surface finish on molded articles while preserving ESD properties
5Reliability
If conventional ESD materials are used, then electrostatic dissipation is achieved, but their performance and effectiveness is often impacted by humidity and they provide only short term ESD properties
Solution Approach 1:
The invention creates a composite material system where high molecular weight ESD agents are integrated with base polymers, forming a stable unified composition that maintains consistent ESD performance across varying humidity conditions and over extended time periods
Solution Approach 2:
The invention changes the molecular weight and chemical structure parameters of the ESD agents, which fundamentally improves their environmental stability and long-term performance consistency, eliminating humidity sensitivity and short-term effectiveness limitations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves stable and effective electrostatic dissipation with reduced surface and volume resistivities, maintaining ESD performance across various conditions without harming the plastic properties or causing halogen contamination, thus enhancing the usability of ESD materials in sensitive applications like electronics.
Implementation Method 1
A halogen-free ESD additive system comprising a thermoplastic polyurethane made by reacting polyol intermediates with diisocyanates and chain extenders, combined with a halogen-free metal salt of amidoalkanesulfonic acid or hydrocarbyl-substituted benzenesulfonic acid, providing inherent electrostatic dissipative properties
Data Source
AI summary
The present invention relates to inherently electrostatic dissipative polymers, such as thermoplastic urethanes (TPU), and compositions thereof. The present invention provides a composition comprising: (a) an inherently dissipative polymer and (b) a halogen-free metal salt of an amidoalkanesulfonic acid, a hydrocarbyl-substituted benzenesulfonic acid, or a mixture thereof, or a polymer derived therefrom. The invention also provides a shaped polymeric article comprising the inherently dissipative polymer compositions described herein. The invention also provides a process of making the inherently dissipative polymer compositions described herein. The process includes the step of mixing a halogen-free metal-containing salt into an inherently dissipative polymer.