Thermosetting Polyurethane Foam Polishing Pad with Spherical Cells
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Solution Overview
Problem
Conventional polishing pads for optical materials and metal surfaces face issues with durability, mechanical strength, adhesion between layers, and environmental impact due to solvent use, leading to poor planarization characteristics and high production costs.
Innovation Solution
A polishing pad with a thermosetting polyurethane foam polishing layer having roughly spherical interconnected cells, formed using an isocyanate component and an active hydrogen-containing compound, which improves durability and adhesion, and is manufactured using a mechanical foaming method that eliminates the need for solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wet curing method is used to manufacture polishing pads, then polishing pads can be produced, but production costs are very high and environmental burden increases due to solvent use
Solution Approach 1:
The patent extracts and eliminates the solvent component from the conventional wet curing manufacturing process. By using a mechanical foaming method instead of solvent-based wet curing, the invention removes the harmful solvent step entirely, thereby reducing environmental burden and manufacturing costs while still achieving the desired porous polishing pad structure.
Solution Approach 2:
The patent replaces the chemical-based wet curing method with a mechanical foaming method. Instead of using solvents and chemical reactions to create the porous structure, the invention uses mechanical energy to introduce air bubbles into the polyurethane resin, which then form the desired cellular structure upon drying, eliminating the need for harmful chemical solvents.
2Reliability
If conventional polishing pads with thin and long cell structure are used, then polishing function is provided, but durability is poor and planarization characteristics deteriorate gradually
Solution Approach 1:
The patent transforms the conventional thin and long cell structure into a spherical cell structure. By making the cells approximately spherical with diameters of 10-100 μm, the invention improves structural integrity and durability while maintaining the porous functionality needed for polishing. The spherical geometry distributes stress more evenly, preventing gradual deterioration of planarization characteristics.
Solution Approach 2:
The patent changes the physical parameters of the cell structure, specifically the cell shape from elongated to spherical and the cell diameter to 10-100 μm. These parameter changes result in improved mechanical strength and durability while maintaining adequate porosity for polishing fluid retention and removal.
3Strength
If conventional polishing pads are used, then polishing function is provided, but adhesion between polishing layer and base material layer is poor causing interfacial release
Solution Approach 1:
The patent applies local quality by creating a gradient in cell size and density through the thickness of the polishing layer. The cells are smaller and more densely packed near the base material layer interface, providing stronger adhesion, while larger cells toward the surface maintain polishing functionality. This localized variation in cell structure optimizes both bonding strength and polishing performance.
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 enhances the durability and stability of the polishing pad, maintaining high planarization characteristics and removal rate stability, while reducing environmental impact and production costs.
Implementation Method 1
the polishing layer comprises a thermosetting polyurethane foam having roughly spherical interconnected cells, the polyurethane foam comprising an isocyanate component and an active hydrogen-containing compound as starting components
Implementation Method 2
manufactured using a mechanical foaming method that eliminates the need for solvents
Data Source
AI summary
A polishing pad of excellent durability and adhesion between the polishing layer and the base material layer includes a polishing layer arranged on a base material layer, wherein the polishing layer includes a thermosetting polyurethane foam having roughly spherical interconnected cells having an average cell diameter of 20 to 300 μm. The polyurethane foam includes an isocyanate component and an active hydrogen-containing compound as starting material components, and the active hydrogen-containing compound includes 30 to 85% by weight of a high-molecular-weight polyol having 2 to 4 functional groups and a hydroxyl value of 20 to 100 mg KOH/g.