Coated Abrasive Size Layer Rheology for Particle Orientation
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Solution Overview
Problem
The flow of size layer precursor and/or supersize layer due to gravity during curing in festoon ovens is a problem, especially when abrasive particles are aligned in a way that impedes flow control, which is exacerbated by the trend towards precise placement and orientation of abrasive particles in coated abrasive articles.
Innovation Solution
A resole phenolic-based curable composition is used, comprising a liquid phenolic resin and an organic polymeric rheology modifier, such as alkali-swellable/soluble polymers, to provide better control of size layer precursor flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If abrasive particles are precisely placed and oriented perpendicular to the backing surface, then manufacturing precision is improved, but gravity-induced flow of size layer precursor worsens
Solution Approach 1:
The patent modifies the rheological parameters of the size layer precursor by adding polymers that change its flow characteristics. Specifically, it uses a combination of thixotropic agents (like colloidal silica or aluminum silicate) and polymers (acrylic or vinyl acrylic copolymers with carboxylic acid groups) to create a composition that resists gravity-induced flow while maintaining ability to be applied. This parameter change in viscosity and flow behavior directly addresses the contradiction by preventing flow even when abrasive particles are precisely oriented.
Solution Approach 2:
The patent creates a composite size layer precursor composition by combining phenolic resin with multiple functional additives including thixotropic agents, polymers with carboxylic acid groups, and other rheology modifiers. This composite material approach allows the size layer to simultaneously achieve precise particle placement retention and resistance to gravity-induced flow during the curing process in festoon ovens.
2Manufacturing precision
If size layer precursor flow is controlled to maintain abrasive particle orientation, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
Rather than complicating the application equipment or process, the patent simplifies the approach by changing the chemical and rheological parameters of the size layer precursor itself. By incorporating specific polymers (acrylic or vinyl acrylic copolymers containing carboxylic acid groups) and thixotropic agents, the composition inherently controls its own flow behavior, eliminating the need for complex external control mechanisms while maintaining precise abrasive particle placement.
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 use of alkali-swellable/soluble polymers in the curable composition enhances flow control, preventing gravity-induced flow issues during curing and maintaining the precise orientation of abrasive particles in coated abrasive articles.
Implementation Method 1
an organic polymeric rheology modifier comprising an alkali-swellable/soluble polymer. These organic polymeric rheology modifiers are presently discovered to provide better control of size layer precursor flow than the techniques previously used.
Implementation Method 2
alkali-swellable/soluble polymers have been used in aqueous compositions for latex paints, personal care products, and drilling muds.
Data Source
Figure 1~2
AI summary
A coated abrasive article comprises a backing having first and second opposed major surfaces, a make layer disposed on at least a portion of the first major surface and bonding abrasive particles to the backing, a size layer overlaid on at least a portion of the make layer and the abrasive particles, and an optional supersize layer. At least one of the size layer or the optional supersize layer comprises an at least partially cured resole phenolic resin and an organic polymeric rheology modifier, and wherein the amount of the at least partially cured resole phenolic resin comprises from 75 to 99.99 weight percent of the combined weight of the at least partially cured resole phenolic resin and the organic polymeric rheology modifier. A method of making the coated abrasive article is also disclosed.