Thermoplastic Polyurethane Composition for Injection Molding
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Solution Overview
Problem
Current methods for processing soft skin materials for vehicle interior parts, such as vacuum molding, powder slush molding, reaction injection molding, and leather wrapping, face limitations in design flexibility, high manufacturing costs, and difficulties in achieving durability, aesthetics, and comfort properties under high-temperature and UV-radiation environments, while also struggling with gas flow marks and weld lines during injection molding.
Innovation Solution
A thermoplastic polyurethane composition is developed for injection molding, comprising an isocyanate compound, ether-containing polyester polyol, chain extender, and multifunctional polydimethylsiloxane-based compound, which imparts slip properties and enhances durability, stability, and tactile sensation, allowing for improved heat-aging resistance, photoaging resistance, and wear resistance, while simplifying processes and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vacuum molding technique is used for processing soft skin material, then manufacturing process is simple, but design flexibility is limited and embossed features cannot be realized
Solution Approach 1:
The patent combines vacuum molding and injection molding into an integrated LIM process, where a skin material layer is vacuum-molded onto a foam core, then injection-molded with TPU resin to achieve both process simplicity and design flexibility in a single manufacturing step
Solution Approach 2:
The patent uses composite material structure with TPU resin containing polydimethylsiloxane compounds that provide both the structural properties needed for injection molding and the surface properties needed for embossed features, resolving the contradiction between process simplicity and design flexibility
2Adaptability or versatility
If PSM technique is used for processing soft skin material, then design flexibility is high, but manufacturing costs are high due to complicated process and high initial investment
Solution Approach 1:
The patent merges vacuum molding and injection molding into LIM, eliminating the need for separate powder preparation and molding steps required in PSM, thereby reducing manufacturing complexity and cost while maintaining design flexibility through the injection molding component
Solution Approach 2:
The patent uses conventional TPU resin as a disposable material that can be directly injection-molded, replacing the expensive and complex powder materials required for PSM, achieving cost reduction while maintaining design flexibility
3Ease of operation
If RIM technique is used for processing soft skin material, then lightweight and flexible products are easily molded, but cycle time is long and raw materials are expensive
Solution Approach 1:
The patent replaces the chemical reaction-based RIM process with a thermal-based injection molding process using TPU resin, which has shorter cycle time and lower material cost while maintaining the ability to produce lightweight and flexible products through appropriate resin formulation
4Productivity
If typical thermoplastic resin materials are injection molded for thin IP skin materials, then production efficiency is high, but appearance problems occur such as gas flow marks and weld lines
Solution Approach 1:
The patent changes the material parameters by incorporating polydimethylsiloxane compounds into the TPU resin formulation, which modifies the melt flow and surface tension characteristics to eliminate gas flow marks and weld lines while maintaining high production efficiency through injection molding
Solution Approach 2:
The patent uses composite TPU resin material containing polydimethylsiloxane compounds that combine the processing advantages of typical thermoplastics with improved surface quality, resolving the contradiction between production efficiency and appearance quality
5Ease of operation
If conventional TPU materials are used for skin materials, then basic functionality is achieved, but durability under high-temperature and UV-radiation environments is insufficient
Solution Approach 1:
The patent uses composite TPU resin containing polydimethylsiloxane compounds that provide enhanced heat-aging and photoaging resistance through the inherent stability of siloxane bonds, while maintaining the basic functionality of TPU materials for skin material applications
Solution Approach 2:
The patent changes the chemical composition parameters of the TPU resin by incorporating polydimethylsiloxane compounds, which fundamentally improves the thermal and UV stability of the material while preserving its basic functional properties
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 composition enables the production of molded articles with excellent performance and aesthetics, reduced manufacturing complexity, and cost savings, contributing to improved fuel efficiency and waste reduction by minimizing material weight and parts, while maintaining high-quality tactile sensation and embossing qualities.
Implementation Method 1
a slip property is imparted to a soft segment due to the presence of chemical bonds in polyurethane molecules
Implementation Method 2
when a chain extender and a multifunctional polydimethylsiloxane-based compound are mixed with an isocyanate- and ether-containing polyester polyol
Data Source
AI summary
The present invention provides a thermoplastic polyurethane composition for injection molding and a method of manufacturing the same. The thermoplastic polyurethane composition for injection molding can be easily injection-molded since a slip property is imparted to a soft segment, and can possess excellent durability properties such as heat-aging resistance, photoaging resistance, and wear resistance, and stability properties such as airbag deployment performance and anti-fogging property, as well as excellent tactile sensation and embossing quality, when a chain extender and a multifunctional polydimethylsiloxane-based compound are mixed with an isocyanate- and ether-containing polyester polyol, and can be useful in simplifying processes, reducing manufacturing costs, and simplifying facilities due to a decrease in the number of parts when molded articles are manufactured using the composition.