Foamed Polyurethane Polishing Pad S Phase Control

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Solution Overview

Problem

Conventional polishing pads generate frictional heat during polishing, causing changes in hardness and potential damage to the object being polished, leading to unstable polishing results.

Innovation Solution

A polishing pad formed by foamed polyurethane with a high content of S phase, exceeding 70% as determined by pulsed NMR measurement at 25°C, and maintaining an S phase ratio of 80% or more at 60°C, which increases the crystallization and hard segment ratio, reducing hardness changes with temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polishing pads are used, then polishing can be performed, but frictional heat causes hardness changes and potential damage to the object being polished

Engineering Contradiction:
Improvestable polishing performanceVSAvoidhardness change due to frictional heat
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the foamed polyurethane by controlling the S phase content to exceed 70% at 25°C and maintaining 80% or more at 60°C. This parameter modification reduces temperature-induced hardness changes, thereby resolving the contradiction between achieving stable polishing performance and preventing hardness changes caused by frictional heat.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If frictional heat is generated during polishing, then polishing action is achieved, but the object to be polished cannot be sufficiently polished or is damaged

Engineering Contradiction:
Improvepolishing efficiencyVSAvoidpolishing quality and surface integrity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

By modifying the physical parameters of the polishing pad material - specifically controlling the S phase content to remain above 70% at 25°C and above 80% at 60°C - the patent maintains dimensional stability and hardness consistency under frictional heat conditions. This ensures both sufficient polishing capability and prevention of damage to the object being polished.

Inventive Principle:
Principle #35Parameter changes

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 polishing pad exhibits a minimal change in hardness with temperature fluctuations, ensuring stable polishing performance by maintaining intermolecular forces between hard segments and suppressing soft segment motion, thus preventing hardness decrease.

Implementation Method 1

a content of S phase in the foamed polyurethane, as determined by pulsed NMR measurement at 25° C., exceeding 70%

Methodology Applied
Scientific EffectPulsed NMR measurement: Electron Paramagnetic Resonance

Implementation Method 2

increases the crystallization and hard segment ratio, reducing hardness changes with temperature

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS10625392B2Polishing pad
Publication Date: 2020.04.21 NITTA HAAS INC

AI summary

The present invention is a polishing pad formed by foamed polyurethane, with a content of S phase in the foamed polyurethane, as determined by pulsed NMR measurement at 25° C., exceeding 70%.