Thermoplastic Polyurethane Polishing Pad Moldability
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Solution Overview
Problem
Conventional polishing pads with non-porous thermoplastic polyurethane molded bodies face challenges in achieving both high moldability and high planarization performance.
Innovation Solution
A polishing-layer molded body with a density of 1.1 g/cm³ or more, composed of a thermoplastic polyurethane polymerized from a monomer including a polymer diol, an organic diisocyanate, a first chain extender with 4 or less carbon atoms, and a second chain extender with 5 or more carbon atoms, optimized with a nitrogen content ratio of 6.3 to 7.4% from the isocyanate group, and featuring a non-porous structure for enhanced moldability and planarization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the hardness of the polishing layer is increased to achieve high planarization performance, then the planarization performance is improved, but the moldability deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the polyurethane by specifying precise ratios of hard segments (20-40 mass%) and soft segments (60-80 mass%), along with controlling the nitrogen content from isocyanate groups at 6.3-7.4 mass%. This parameter optimization enables achieving both high hardness for planarization performance and good moldability, resolving the contradiction between these two requirements.
Solution Approach 2:
The invention uses a composite polyurethane structure combining hard segments (from diisocyanate and chain extenders) and soft segments (from polymer diol) in specific proportions. This composite structure allows the material to exhibit both the hardness needed for planarization and the flexibility required for moldability, effectively resolving the technical contradiction.
2Manufacturing precision
If the density of the polishing layer is increased to achieve high planarization performance, then the planarization performance is improved, but the flexibility deteriorates
Solution Approach 1:
The invention optimizes the density parameter within a specific range (1.05-1.20 g/cm³) by controlling the hard/soft segment ratio and nitrogen content. This controlled parameter change achieves high planarization performance while maintaining sufficient flexibility for effective polishing operation, resolving the contradiction between density-related performance and operational flexibility.
Solution Approach 2:
The invention creates local quality differentiation within the polishing layer by distributing hard and soft segments in a controlled manner. The hard segments provide localized hardness for planarization where needed, while the soft segments maintain overall flexibility for contact with the polishing surface, resolving the contradiction between density and flexibility.
Data Source
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AI summary
Disclosed is a polishing-layer molded body including: a thermoplastic polyurethane that is a polymer of a monomer including: a polymer diol; an organic diisocyanate; a first chain extender including a diol having 4 or less carbon atoms; a second chain extender including a diol having 5 or more carbon atoms, a content ratio of nitrogen derived from an isocyanate group of the organic diisocyanate being 6.3 to 7.4 mass%, and the polishing-layer molded body being non-porous.