Polyurethane Adhesive Thixotropic Wax Composition
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Solution Overview
Problem
Existing polyurethane adhesive compositions face challenges in achieving a balance between easy application and controlled spreading, particularly in industrial processes, with thixotropic agents like fumed silica requiring lengthy degassing and affecting adhesive properties.
Innovation Solution
An adhesive composition incorporating hydrogenated castor wax and amide wax as thixotropic agents, which allows for precise application and reduced degassing time, while maintaining compatibility and stability, with a preferred polyol to thixotropic agent ratio of 80:20 to 99:1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fumed silica is used as a thixotropic agent, then the adhesive composition achieves controlled spreading and stability, but the degassing process is prolonged due to bubble formation from the uneven silica surface
Solution Approach 1:
The patent changes the physical and chemical parameters of the thixotropic agent by using hydrogenated castor wax and amide wax instead of fumed silica. This substitution fundamentally alters the surface properties and bubble-forming characteristics of the adhesive composition, enabling rapid degassing while maintaining thixotropic stability and adhesion performance.
Solution Approach 2:
The patent employs readily available waxes (hydrogenated castor wax and amide wax) that are easier to process and incorporate than fumed silica. These materials provide the necessary thixotropic effect without the processing complications of silica, effectively replacing a problematic material with simpler alternatives that achieve the same functional goal without the drawbacks.
2Ease of operation
If the polyurethane adhesive has low viscosity for easy application, then the application process is fast and easy, but the adhesive spreads unnecessarily after application
Solution Approach 1:
The patent introduces dynamic rheological properties to the adhesive through thixotropic agents (hydrogenated castor wax and amide wax). The adhesive exhibits time-dependent viscosity changes: it remains fluid during application when stress is applied, then gradually increases in viscosity after application when stress is removed, automatically controlling spread and maintaining shape without requiring high initial viscosity.
Solution Approach 2:
The patent changes the viscosity parameter of the adhesive over time through thixotropic modification. The adhesive transitions from a lower viscosity state during application (enabling easy coating) to a higher viscosity state after application (preventing spread), effectively decoupling the viscosity requirements for application versus post-application stability.
3Shape
If the polyurethane adhesive has high viscosity to prevent spreading, then the adhesive maintains its shape after application, but the application process becomes difficult and slow
Solution Approach 1:
The patent employs dynamic thixotropic behavior to resolve the viscosity contradiction. During application, mechanical stress temporarily reduces viscosity, enabling easy and fast coating operations. Once applied, the stress is removed and viscosity naturally recovers, providing automatic shape retention and spread control without requiring the adhesive to be inherently high-viscosity from the start.
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 adhesive composition exhibits improved flowability and stability, reducing spreading and enhancing penetration, making it suitable for manufacturing water filter membranes with a significantly shortened degassing process.
Implementation Method 1
the use of thixotropic agents in the adhesive composition which help to control the time-dependent shear thinning properties of the adhesive composition. In the presence of a thixotropic agent, certain gels or fluids which are thick or highly viscous will become thin and flowable when shaken, agitated, sheared or otherwise stressed. Once the stress is released, the gel or fluid will return to its more viscous state.
Data Source
AI summary
The present invention refers to an adhesive composition comprising a thixotropic agent, a polyurethane adhesive obtained from the adhesive composition as well as to the thixotropic agent comprised in the adhesive composition.