Acrylate color-stabilized phenolic bound abrasive products and methods for making same

Abstract

Described is a color-stable abrasive article that includes a phenolic resin binder; a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one acrylate. The color-stable abrasive article is formed by a method including the steps of blending a resole and a color stabilizer to form a resole composition; contacting a plurality of abrasive particles with the resole composition; and curing the resole composition to produce the color-stable abrasive article. Thus provided are color stabilized phenolic bound abrasives and a method for making such abrasives that resist color change over time and upon exposure to high temperature and maintain the mechanical strength of a phenolic resin.

Description

RELATED APPLICATION[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 199,471, filed on Nov. 17, 2008. The entire teachings of the above application are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The term “phenolic resin” describes a wide variety of resin products that result from the reaction product of phenols and aldehydes. Phenols react with formaldehydes under both acidic and basic conditions. If a based-catalyzed mixture of a phenol and a formaldehyde contains one or more moles of formaldehyde per moles of phenol, it will produce a thermosetting (one-step) resin, or “resole.” Common base compounds employed as catalysts for resole resins include the hydroxides of alkali metals, such as sodium, potassium, or lithium. While alkali metal hydroxide-catalyzed phenolic resins are commercially useful, they have an undesirable tendency to darken as they age, are heated or otherwise cured. The extent of darkening is known to be depend...

AI Technical Summary

Benefits of technology

The present invention provides a color-stable abrasive article that includes a phenolic resin binder, a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one acrylate. The method of making the abrasive article involves blending a resole and a color stabilizer to form a resole composition, contacting abrasive particles with the resole composition, and curing the resole composition. The color-stable abrasive article is resistant to color change over time and maintains the mechanical strength of a phenolic resin. The technical effect of the invention is to provide an abrasive article that can effectively remove a portion of a work surface without causing color change or compromising the mechanical strength of the binder.

Problems solved by technology

While alkali metal hydroxide-catalyzed phenolic resins are commercially useful, they have an undesirable tendency to darken as they age, are heated or otherwise cured.

The resin darkening problem is particularly pronounced in coated abrasive and three-dimensional, low density abrasive products because of the more visible presence of the bond system.

Also, since the darkening increases with temperature and exposure time, any variation in the temperature profile of the product results in color variation within the product itself.

Color variation is particularly noticeable for light-colored products, causing such products to be unacceptable for aesthetic or other reasons.

The darkening of the resin can interfere with the desired coloration, causing the final product to have a different color from the colorant added.

While this achieves color stability, it also imparts brittleness, takes longer to cure, and results in mechanical weakness and therefore reduced grinding performance in the finished product.

However, this method is not sufficiently effective in stabilizing the color of phenolic resin products having certain colorants, such as light blue and orange pigments or dyes.

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