WO2016109780A1

WO2016109780A1 - Colored abrasive articles and method of making colored abrasive articles

Info

Publication number: WO2016109780A1
Application number: PCT/US2015/068245
Authority: WO
Inventors: Michael W. Klett; Davinder S. DHAMI
Original assignee: Saint-Gobain Abrasives, Inc.; Saint-Gobain Abrasifs
Priority date: 2014-12-31
Filing date: 2015-12-31
Publication date: 2016-07-07
Also published as: US20160184971A1

Abstract

Embodiments of the present disclosure are directed to methods of making high grade colored abrasive articles that are color stable at high temperatures, such as color stable at temperatures of at least about 185 degrees Celsius such that the bonded abrasive body can be cured at such elevated temperatures without substantially changing the color of the bonded abrasive body.

Description

COLORED ABRASIVE ARTICLES AND METHOD OF MAKING COLORED

ABRASIVE ARTICLES TECHNICAL FIELD

The present disclosure relates to abrasive articles and methods of making abrasive articles, and more particularly to colored abrasive articles and methods of making colored abrasive articles.

BACKGROUND ART

Colored bonded abrasive articles formed from high grade bond materials have not been able to be produced with traditional methods. During curing and ageing of such abrasive articles formed form high grade bond materials, the bond material substantially darkens such that a dark brown to black color is created. Further, traditional color additives and processes used in making colored bonded abrasive articles formed from lower grade bond materials could not overcome the substantial darkening of the bond material and/or would degrade the strength and toughness of the bond material. As such, colored bonded abrasive articles formed from high grade bond materials that retain their high strength and toughness have been unachievable.

In contrast to the state of art, the present inventors have surprisingly discovered the ability to create colored bonded abrasive articles formed from high grade bond materials that do not suffer from performance degradations due to the impartation of color.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in the

accompanying figures.

FIG. 1 includes an illustration of a top view of an abrasive article according to one embodiment, and

FIG. 2 includes an illustration of a side view of the abrasive article of FIG. 1.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other embodiments can be used based on the teachings as disclosed in this application.

As used herein, the phrase "color instability" refers to the material's tendency to substantially darken during curing.

The terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one, at least one, or the singular as also including the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in textbooks and other sources within the abrasive arts.

Certain embodiments of the present disclosure are generally directed to colored abrasive articles and methods of making colored abrasive articles, where the bond material is a high grade bond material that is susceptible to color instability during curing. The bond material can include a color additive that substantially changes the inherent color of the bond material, and the new color is generally maintained after formation and curing of the bonded abrasive body. The concepts are better understood in view of the embodiments described below that illustrate and do not limit the scope of the present invention

Referring now to FIG. 1, an abrasive article 10 can include a bonded abrasive body 20 comprising abrasive particles 40 contained within a bond material 30. As described above, in particular embodiments, the bond material 30 can be susceptible to color instability during curing. For example, the bond material 30 can be susceptible to color instability during curing due to the presence of a particular content of certain reactive groups, such as oxidizable reactive groups.

In certain embodiments, the bond material 30 can have a high glass transition temperature (Tg). For example, the bond material can have a glass transition temperature (Tg) of at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, or even at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C.

Further, the bond material can have a glass transition temperature (Tg) of not greater than about 350°C, not greater than about 320°C or not greater than about 300°C. Moreover, the bond material can have a glass transition temperature (Tg) in a range of any of the minimums and maximums provided above, such as in a range of from about 150°C to about 350°C, or even from about 155°C to about 300°C.

In certain embodiments, the bond material 30 can be a reaction product of various reaction constituents. For example, in certain embodiments, the bond material 30 can be a reaction product of constituents including a first resin and a second resin that is distinct from the first resin.

In particular embodiments, the first resin can be a resole. As used herein, a resole resin refers to a phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of greater than one and is a base-catalyzed resin.

In certain embodiments, the bonded abrasive body can have a particular content of the first resin based on the total weight of the first and second resin. For example, the bonded abrasive body can have a content of the first resin of at least about 5 wt.%, at least about 8 wt.%, at least about 10 wt.%, or at least about 12 wt.% based on the total weight of the first and second resins. Further, the bonded abrasive body can have a content of the first resin of not greater than about 80 wt.%, not greater than about 75 wt.%, or even not greater than about 70 wt.% based on the total weight of the first and second resins. Moreover, the bonded abrasive body can have a content of the first resin in a range of any of the minimums and maximums provided above, such as in a range of from about 5 wt.% to about 80 wt.%, or even 10 wt.% to 75 wt.%, based on the total weight of the first and second resins. In particular embodiments, the second resin can be a novolac resin. As used herein, a novolac resin refers to a phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of less than one and is an acid-catalyzed resin.

In certain embodiments, the bonded abrasive body can have a particular content of the second resin. For example, the bonded abrasive body can have a content of the second resin of at least about 5 wt.%, at least about 8 wt.%, at least about 10 wt.%, or at least about 12 wt.% based on the total weight of the first and second resins. Further, the bonded abrasive body can have a content of the second resin of not greater than about 80 wt.%, not greater than about 75 wt.%, or even not greater than about 70 wt.% based on the total weight of the first and second resins. Moreover, the bonded abrasive body can have a content of the second resin in a range of any of the minimums and maximums provided above, such as in a range of from about 5 wt.% to about 80 wt.%, or even 10 wt.% to 75 wt.%, based on the first and second resins.

In certain embodiments, the bond material 30 can further include a hardener. The hardener can be present in the first resin, the second resin, or a combination thereof. In particular embodiments, the hardener can be present in the second resin. The hardener can serve to increase the crosslinking density of the bond material, and therefore increase its hardness.

In particular embodiments, the hardener can include hexamethylenetetramine

(HMTA).

In certain embodiments, the bond material 30 can further be described by the type of crosslink bridges that are formed after curing. In particular embodiments, the bond material can include a significant amount of methylene and/or dimethylene amino crosslink bridges. For example, in certain embodiments, the bond material can include an average of at least about 40%, at least about 50%, at least about 60%, or even at least about 70% of dimethylene amino crosslink bridges based on the total average amount of crosslink bridges in the cured bond material.

As discussed herein, the abrasive article 10 can include a bonded abrasive body 20 containing abrasive particles 40 dispersed within the bond material 30.

In certain embodiments, the bonded abrasive body 20 can further include a color additive. For example, a color additive can be combined with a mixture including the bond material 30 and the abrasive particles 40 and cured to form a colored bonded abrasive article that has a different color than the bonded abrasive body without the color additive. In certain embodiments, the color additive can include a pigment, a dye, or combinations thereof. In particular embodiments, the color additive can include a pigment.

In particular embodiments, the color additive can be an organic color additive.

In certain embodiments, the color additive can be described as a thermally stable color additive. As used herein, a color additive is thermally stable at a particular temperature if the color additive does not break down at that temperature.

Accordingly, in particular embodiments, the color additive can have a thermal stability of at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C.

Another characteristic to describe particular color additives is their solubility. In particular embodiments, the color additive can be soluble in the same solvent used with the bond material. In this way, the color additive can have good dispersability and mixing with the bond material resins and abrasive particles during production. In very particular embodiments, the color additive can be an organic pigment that is soluble with at least one resin forming the bond material.

In certain embodiments, the bonded abrasive body 20 can further include a filler material that is distinct from the abrasive particles 40, and also dispersed within the bond material 30. For example, the filler can have a hardness that is less than the hardness of the abrasive particle. Like the abrasive particles, the filler material can be disposed within the bond material 30.

In certain embodiments, the filler can be in the form of powders, granules, spheres, fibers, or a combination thereof.

In certain embodiments, the filler can be an inorganic material. In other

embodiments, the filler can be an organic material. In still further embodiments, the filler can include a combination of inorganic fillers and organic fillers.

In particular embodiments, the filler can include nepheline syenite, sand, bubble alumina, bauxite, chromites, magnesite, dolomites, bubble mullite, borides, titanium dioxide, carbon products, flour, clay, talc, hexagonal boron nitride, molybdenum disulfide, feldspar, glass spheres, glass fibers, CaF₂, KBF₄, Cryolite (Na₃AlF6), potassium Cryolite (K₃AIF₆) , pyrites, ZnS, copper sulfide, mineral oil, fluorides, carbonates, calcium carbonate, or a combination thereof. In certain embodiments, the filler can also have a particular color. For example, the filler can have any of the colors identified below in regards to the bond material as quantified in the CIELAB color system. In further embodiments, the filler can have a color that is substantially similar to the color of the pigmented bond material. In very particular embodiments, the filler can be essentially free of a black filler, such as carbon black. For example, traditionally, carbon black filler was the typical filler employed due to the color instability of the bond material causing the bond material to substantially darken during curing.

In addition to the filler, the bonded abrasive body can further include other additives. For example, other desirable additives can include an antistatic agent, a metal oxide, a lubricant, a porosity inducer, coloring agent, or a combination thereof.

In certain embodiments, the bonded abrasive body can have a particular content of bond material. For example, the bonded abrasive body can have a content of bond material of at least about 5 wt.%, at least about 10 wt.%, at least about 15 wt.%, or even at least about 20 wt.% based on the total weight of the bonded abrasive body. Further, the bonded abrasive body can have a content of bond material of not greater than about 80 wt.%, not greater than about 75 wt.%, or even not greater than about 70 wt.% based on the total weight of the bonded abrasive body. Moreover, the bonded abrasive body can have a content of bond material in a range of any of the minimums and maximums provided above, such as in a range of from about 5 wt.% to about 80 wt.%, or even 10 wt.% to 75 wt.%, based on the total weight of the bonded abrasive body.

In certain embodiments, the bonded abrasive body can have a particular content of abrasive particles. For example, the bonded abrasive body can have a content of abrasive particles of at least about 5 wt.%, at least about 10 wt.%, or even at least about 15 wt.% based on the total weight of the bonded abrasive body. Further, the bonded abrasive body can have a content of abrasive particles of not greater than about 50 wt.%, not greater than about 45 wt.%, or even not greater than about 40 wt.% based on the total weight of the bonded abrasive body. Moreover, the bonded abrasive body can have a content of abrasive particles in a range of any of the minimums and maximums provided above, such as in a range of from about 5 wt.% to about 50 wt.%, or even from about 10 wt.% to about 45 wt.% based on the total weight of the bonded abrasive body.

In certain embodiments, the bonded abrasive body can have a particular content of color additive. For example, the bonded abrasive body can have a content of color additive of at least about 0.01 wt.%, at least about 0.05 wt.%, at least about 0.1 wt.%, or even at least about 1 wt.% based on the total weight of the bonded abrasive body. Further, the bonded abrasive body can have a content of color additive of not greater than about 20 wt.%, not greater than about 15 wt.%, no greater than about 10 wt.%, or even not greater than about 5 wt.% based on the total weight of the bonded abrasive body. Moreover, the bonded abrasive body can have a content of color additive in a range of any of the minimums and maximums provided above, such as in a range of from about 0.01 wt.% to about 10 wt.% based on the total weight of the bonded abrasive body.

In certain embodiments, the bonded abrasive body can have a particular content of filler material. For example, the bonded abrasive body can have a filler content of at least about 1 wt.%, at least about 3 wt.%, or even at least about 5 wt.% based on the total weight of the bonded abrasive body. Further, the bonded abrasive body can have a filler content of not greater than about 30 wt.%, not greater than about 25 wt.%, or even not greater than about 20 wt.% based on the total weight of the bonded abrasive body. Moreover, the bonded abrasive body can have a filler content in a range of any of the minimums and maximums provided above, such as in a range of from about 1 wt.% to about 30 wt.%, or even from about 3 wt.% to about 25 wt.% based on the total weight of the bonded abrasive body.

In certain embodiments, the bonded abrasive body can have a particle shape. For example, and referring to FIGS. 1 and 2, the bonded abrasive body can have a thickness (t) extending axially across the body, and a diameter (D) extending radially across the body.

In particular embodiments, the bonded abrasive body can have a particular ratio of the diameter to the thickness. For example, the ratio of the diameter to the thickness can be at least about 10:1, at least about 20:1, at least about 50:1, or at least about 100:1. In further embodiments, the ratio can be not greater than about 10,000:1, or not greater than 5,000:1. Moreover, the ratio of the diameter to the thickness can be in a range of any of the minimums and maximums provided above, such as in a range of from about 10: 1 to about 10,000: 1.

As described throughout this document, the bonded abrasive article can have a desired color, and particularly a color other than the inherent color of the bond material, such a color other than generally black or dark brown.

As used herein, color can be described and quantified using the CIE L*a*b* color system, as is well understood in the art.

The CIE L*a*b* color system includes a three dimensional coordinate system to assign a numerical value to a color. The vertical L* axis represents Lightness, ranging from 0-100. The other (horizontal) axes are represented by a* and b*. These are at right angles to each other and cross each other in the center, which is neutral (grey, black or white). They are based on the principal that a color cannot be both red and green, or blue and yellow. The a* axis is green at one extremity (represented by -a), and red at the other (+a). The b* axis has blue at one end (-b), and yellow (+b) at the other. The center of each axis is 0. A value of 0, or very low numbers of both a* and b* will describe a neutral or near neutral color. In theory there are no maximum values of a* and b*, but in practice they are usually numbered from -128 to +127 (256 levels). The CIE Lab color model encompasses the entire spectrum, including colors outside of human vision.

Traditional methods and materials used to make the high grade bond material described herein could only be produced in a dark color, such as dark brown to black. Within the CIELAB color system, the general colors of dark brown to black can have a CIELAB values of L* less than about 20. Accordingly, in particular embodiments, the bonded abrasive body can have a color other than generally dark brown to black, i.e., a color having CIELAB values other than an L* of less than about 20.

Put another way, in certain embodiments, the bonded abrasive body can have a color having

a L* of at least about 20, at least about 30, or even at least about 35; an L* of not greater than about 95, not greater than about 90, not greater than about 85, not greater than about 80, or even not greater than about 75; or an L* in a range of any of the minimums and maximums provided above;

an a* of at least about 20 or less than -20, at least about 40 or less than -40, or even at least about 50 or less than -50; an a* of not great than 1000 or greater than -1000, not greater than 500 or greater than -500; not greater than about 256 or greater than -256; or an a* in a range of any of the minimums and maximums provided above; and

a b* of at least about 20 or less than -20, at least about 40 or less than -40, or even at least about 50 or less than -50; a b* of not greater than 1000 or greater than -1000, not greater than 500 or greater than -500; not greater than about 256 or greater than -256; or a b* in a range of any of the minimums and maximums provided above.

In particular embodiments, a bonded abrasive body can have an a* of greater than 20 or less than about -20 and a b* in a range of from about -256 to about 256.

In further particular embodiments, a bonded abrasive body can have a b* of greater than about 20 or less than about -20 and an a* in a range of from about -256 to about 256. In particular embodiments, the bonded abrasive body can have a generally green color having a L* in a range of from about 20 to about 80; an a* of less than about -20; and a b* in a range of from -256 to 256.

In particular embodiments, the bonded abrasive body can have a generally red color having a L* in a range of from about 20 to about 80; an a* of at least about 20 and a b* in a range of from -256 to 256.

In particular embodiments, the bonded abrasive body can have a generally orange color having a L* in a range of from about 20 to about 80; an a* in a range of at least about 20 and a b* of at least about 20.

In particular embodiments, the bonded abrasive body can have a generally yellow color having a L* in a range of from about 20 to about 80; a b* in a range of at least about 20 and an a* in a range of from—256 to 256.

In particular embodiments, the bonded abrasive body can have a generally green color having a L* in a range of from 20 to 80; an a* of not greater than -20; and a b* in a range of from -256 to 256.

In particular embodiments, the bonded abrasive body can have a desirable color difference from the same bonded abrasive body without a color additive. In further embodiments, the bonded abrasive body can have a desirable color difference from the same bonded abrasive body except cured in an ambient air atmosphere. For example, traditional color additives were ineffective in producing a substantial different color due to the inherent color instability of the bond material at elevated cure temperatures. In contrast, the present inventors have surprisingly discovered that a substantial color difference from the inherent color of the cured bond material can be obtained without sacrificing performance of the abrasive article. Accordingly, the current inventors were surprisingly able to construct bonded abrasive bodies having a multitude of different color possibilities.

To standardize color differences, the International Commission on Illumination (CIE) has developed a color difference formula, AE*ab (also called ΔΕ* or ΔΕ) used to denote difference of color sensation. Using

of two colors in L*a*b*, ΔΕ is:

Accordingly, in particular embodiments, the bonded abrasive body can have a color difference (ΔΕ) of at least about 5, at least about 10, at least about 15, at least about 20, at least about 30, at least about 40, at least about 50, or even at least about 60 compared to the inherent color of the cured bond material without a color additive.

In certain embodiments, the bonded abrasive body can have an advantageous wear rate. The wear rate is a measure of the amount of material that is removed from the bonded abrasive body when subjected to a standardized abrading procedure.

The wear rate value of the bonded abrasive bond can be useful to distinguish between different grades of abrasive articles. For example, the stronger and tougher the bond material is, the lower the wear rate value will be. Furthermore, traditionally, it was not possible to create a colored bonded abrasive body using materials that gave the bonded abrasive body a lower rate. Attempts to impart such color resulted in deterioration of the strength and toughness of the bonded abrasive body, and therefore increased the wear rate. In contrast, the current inventors surprisingly discovered the ability to create a colored bonded abrasive body without deteriorating the toughness and strength, and therefore maintaining desirable wear rates.

Accordingly, in certain embodiments, the bonded abrasive body can have an advantageous wear rate, consistent with the same abrasive article without the impartation of color.

In certain embodiments, the bonded abrasive body can have an advantageous material removal rate. The material removal rate is measure of the amount of material that is removed from the workpiece when subjected to a standardized abrading procedure.

In further embodiments, the material removal rate (MRR) of the bonded abrasive bond can be useful to distinguish between different grades of abrasive articles. For example, the stronger and tougher the bond material is, the higher the material removal rate value will be. Furthermore, traditionally, it was not possible to create a colored bonded abrasive body using materials that gave the bonded abrasive body a higher rate. Attempts to impart such color resulted in deterioration of the strength and toughness of the bonded abrasive body, and therefore decreased the material removal rate. In contrast, the current inventors surprisingly discovered the ability to create a colored bonded abrasive body without deteriorating the toughness and strength, and therefore maintaining desirable material removal rates.

Accordingly, in certain embodiments, the bonded abrasive body can have an advantageous material removal rate consistent with the removal rate of the same bonded abrasive article without the impartation of color.

Another aspect of certain embodiments of the present disclosure is directed to a method of forming an abrasive article. It is to be understood that all of the characteristics and features of the abrasive article described above also apply to embodiments directed to a method of forming the abrasive article. For example, the method can include forming a bonded abrasive body having the dimensions, color, and wear rates, among other properties, provided above.

In general, certain embodiments of the method can include:

providing a bond material precursor;

providing abrasive particles;

mixing the abrasive particles with the bond material precursor;

curing the mixture to form a bonded abrasive body with abrasive particles dispersed within a cured bond material.

In certain embodiments, providing the bond material precursor can include providing a first resin and a second resin which is different from the first resin.

For example, in particular embodiments, mixing the abrasive particles with the bond material precursor can include pre-coating the abrasive particles with the first resin.

Furthermore, the method can further include mixing the second resin with the coated abrasive particles. It is to be understood that the first and second resins can be those described above. For example, the first resin can be a resole and the second resin can be a novolac resin.

In particular embodiments, curing the mixture to form a bonded abrasive body can include curing the mixture in a non-oxidative atmosphere. For example, the non-oxidative atmosphere can consist essentially of an inert gas, such as nitrogen. In very particular embodiments, curing the mixture to form a bonded abrasive body can include curing the mixture in an atmosphere consisting essentially of nitrogen.

In certain embodiments, curing the mixture to form a bonded abrasive body can include curing the mixture at a relatively high temperature. For example, as discussed above, particular advantages of certain embodiments of the present disclosure is the ability to impart a desired color to high grade bond materials that a have a high strength and high toughness. Typically, such high grade bond materials have a high cure temperature to obtain the high strength and toughness. Without wishing to be bound by any one theory, it is believed that the high cure temperature is partly responsible for the extreme difficulty in creating high performing, colored, bonded abrasive bodies due in part to the limitation on color additives and the inherent color instability of the bond material at such high cure temperatures.

Accordingly, in particular embodiments, curing the mixture to form a bonded abrasive body can include curing the mixture at a temperature of at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, or even at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C. In further embodiments, curing the mixture to form a bonded abrasive body can include curing the mixture at a temperature of no greater than about 350°C, not greater than about 320°C or not greater than about 300°C. Moreover, curing the mixture to form a bonded abrasive body can include curing the mixture at a temperature in a range of any of the minimums and maximums provided above, such as in a range of from about 150°C to about 350°C, or even from about 155°C to about 300°C.

The present disclosure represents a departure from the state of the art. Heretofore, it was not possible to create a colored high grade bonded abrasive body that maintained its high grade attributes such as strength and toughness while imparting a desired color. For example, traditional materials and processes used to create a high grade bonded abrasive body would substantially darken during curing to give a generally black or dark brown color. Addition of color additives could not overcome the substantial darkening of the bond material that traditionally, inherently occurred. Further, attempts to prevent the substantial darkening of the bond material during curing and ageing resulted in a degradation of the performance of the bonded abrasive body, in, for example, strength, toughness, and crosslink density and therefore wear rate. Accordingly, such high grade bonded abrasive bodies were only able to be produced in a black or a dark brown color. Moreover, it was unknown what was causing the substantial darkening during curing and ageing and how to alleviate such inherent effect without deteriorating the performance of the high grade bonded abrasive bodies. In contrast, and as illustrated in more detail by the Examples below, the bonded abrasive bodies according to certain embodiments of the present disclosure were surprisingly able to have a color other than black or dark brown and maintain desired performances in strength, toughness, crosslink density, wear rate, and others. Without wishing to be bound by any one theory, the modification to the processing and particularly curing of the bonded abrasive body described herein has generally prevented the bond material from substantially darkening during curing and ageing without significantly affecting its performance. For example, at least, the modification to an inert atmosphere during curing is believed to have substantially decreased the oxidation in the bond material which is theorized to have resulted in the general prevention of substantial darkening during curing and ageing thus allowing particular color additives to impart color while maintaining performance.

Many different aspects and embodiments are possible. Some of those aspects and embodiments are described below. After reading this specification, skilled artisans will appreciate that those aspects and embodiments are only illustrative and do not limit the scope of the present invention. Embodiments may be in accordance with any one or more of the items as listed below.

Embodiment 1. An abrasive article comprising: a bonded abrasive body comprising abrasive particles contained within a bond material, wherein the bond material has a glass transition temperature of at least about 200°C; and wherein the bonded abrasive body is color stable.

Embodiment 2. An abrasive article comprising: a bonded abrasive body comprising abrasive particles contained within a bond material, wherein the bond material has a glass transition temperature of at least about 200°C; and wherein the bonded abrasive body further comprises at least one pigment.

Embodiment 3. An abrasive article comprising: a bonded abrasive body comprising abrasive particles contained within a bond material, wherein the bond material has a glass transition temperature of at least about 200°C, and wherein the bond material has a color defined by the CIELAB color system of a L* in a range of from 20 to 80; AND an a* of greater than 20 or less than about -20 and a b* in a range of from about -256 to about 256;

OR a b* of greater than about 20 or less than about -20 and an a* in a range of from about -

256 to about 256.

Embodiment 4. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bond material is essentially free of an acrylate.

Embodiment 5. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bond material has a glass transition temperature of at least at least about 150°C, or at least about 155°C, or at least about 160°C, or at least about 165°C, or at least about 170°C, or at least about 175°C, or at least about 180°C, or at least about 185°C, or even at least about 190°C, at least about 195°C, or at least about 200°C, or at least about 205°C, or at least about 210°C, or at least about 215°C, or at least about 220°C, or even at least about 225°C.

Embodiment 6. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bond material comprises a glass transition temperature of not greater than 350°C, or not greater than 320°C or at least 300°C.

Embodiment 7. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a bond material content of at least about 5 wt.% based on the total weight of the body, and wherein the bonded abrasive body has a bond material content of not greater than about 80 wt.% based on the total weight of the body. Embodiment 8. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bond material comprises a cured and cross-linked reaction product of a first resin and a second resin distinct from the first resin.

Embodiment 9. The abrasive article of any one of embodiments 1, 2 and 3, wherein the first resin is a resole.

Embodiment 10. The abrasive article of any one of embodiments 1, 2 and 3, wherein the first resin is a phenol-formaldehyde resin having formaldehyde to phenol molar ratio of greater than one.

Embodiment 11. The abrasive article of any one of embodiments 1, 2 and 3, wherein the first resin is a base-catalyzed resin.

Embodiment 12. The abrasive article of any one of embodiments 1, 2 and 3, wherein the second resin comprises a novolac resin.

Embodiment 13. The abrasive article of any one of embodiments 1, 2 and 3, wherein the second resin is a phenol-formaldehyde resin having formaldehyde to phenol molar ratio of less than one.

Embodiment 14. The abrasive article of any one of embodiments 1, 2 and 3, wherein the second resin is an acid-catalyzed resin.

Embodiment 15. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a content of the second resin of at least about 5 wt.%, or at least about 8 wt.%, or at least about 10 wt.%, or at least about 12 wt.% based on the total weight of the bonded abrasive body; and wherein the bonded abrasive body has a content of the second resin of not greater than about 90 wt.%.

Embodiment 16. The abrasive article of any one of embodiments 1, 2 and 3, wherein the second resin comprises a hardener comprising hexamethylenetetramine (HMTA).

Embodiment 17. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bond material includes a significant amount of methylene and dimethylene amino crosslink bridges.

Embodiment 18. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises a pigment.

Embodiment 19. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises an organic pigment.

Embodiment 20. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises a pigment having a thermal stability of at least about 150°C, or at least about 155°C, or at least about 160°C, or at least about 165°C, or at least about 170°C, or at least about 175°C, or at least about 180°C, or at least about 185°C, or even at least about 190°C, at least about 195°C, or at least about 200°C, or at least about 205°C, or at least about 210°C, or at least about 215°C, or at least about 220°C, or even at least about 225°C.

Embodiment 21. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises a pigment that is soluble in an aqueous solvent.

Embodiment 22. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises an inorganic pigment.

Embodiment 23. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has an abrasive particle content of at least about 5 wt.% based on the total weight of the body, and wherein the bonded abrasive body has an abrasive particle content of not greater than about 50 wt.% based on the total weight of the body.

Embodiment 24. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler that is distinct from the abrasive particles.

Embodiment 25. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler in the form of powders, granules, spheres, fibers, or a combination thereof.

Embodiment 26. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler comprising an inorganic material.

Embodiment 27. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler comprising an organic material.

Embodiment 28. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler disposed within the bond material.

Embodiment 29. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler comprising nepheline syenite, sand, bubble alumina, bauxite, chromites, magnesite, dolomites, bubble mullite, borides, titanium dioxide, carbon products, flour, clay, talc, hexagonal boron nitride, molybdenum disulfide, feldspar, glass spheres, glass fibers, CaF₂, KBF₄, Cryolite (Na₃AlF₆), potassium Cryolite (K₃AlFe) , pyrites, ZnS, copper sulfide, mineral oil, fluorides, carbonates, calcium carbonate, or a combination thereof.

Embodiment 30. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body further comprises a filler comprising an antistatic agent, a metal oxide, a lubricant, a porosity inducer, coloring agent, and a combination thereof and wherein the filler is distinct from the abrasive particles. Embodiment 31. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a filler content of at least about 1 wt.% based on the total weight of the body, and wherein the bonded abrasive body has a filler content of not greater than about 30 wt.% based on the total weight of the body.

Embodiment 32. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body is essentially free of a black filler.

Embodiment 33. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a porosity of at least about 1 vol.% based on the total volume of the body, and wherein the bonded abrasive body has a porosity of not greater than about 50 vol.% based on the total volume of the body.

Embodiment 34. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a diameter (D) extending radially across the body and a thickness (t) extending axially across the body, wherein the body comprises a ratio of the diameter to the thickness of at least about 10:1, or at least about 20:1, or at least about 50:1, or at least about 100 : 1.

Embodiment 35. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a color defined by the CIELAB color system of:

a L* in a range of 20 to 80, or 30 to 75, or even 35 to 75;

an a* of at least about 20 or less than -20, at least about 40 or less than -40, or even at least about 50 or less than -50; AND a b* of not greater than 1000 or greater than -1000, not greater than 500 or greater than -500; not greater than about 256 or greater than -256; OR an a* of not great than 1000 or greater than -1000, not greater than 500 or greater than -500; not greater than about 256 or greater than -256; AND b* of at least about 20 or less than -20, at least about 40 or less than -40, or even at least about 50 or less than -50.

Embodiment 36. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a generally green color defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* of less than about -20; and a b* in a range of from -256 to 256.

Embodiment 37. The abrasive article of any one of the preceding embodiments, wherein the bonded abrasive body has a generally red color defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* of at least about 20 and a b* in a range of from -256 to 256.

Embodiment 38. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a generally orange color defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* in a range of at least about 20 and a b* of at least about 20.

Embodiment 39. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a generally yellow color defined by the CIELAB color system of a L* in a range of from about 20 to about 80; a b* in a range of at least about 20 and an a* in a range of from -256 to 256.

Embodiment 40. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a generally green color defined by the CIELAB color system of a L* in a range of from 20 to 80; an a* of not greater than -20; and a b* in a range of from - 256 to 256.

Embodiment 41. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body comprises a reinforcing layer extending radially through at least a portion of the body, wherein the reinforcing layer comprises a reinforcing material comprising a fabric, a fiber, a film, a woven material, a non-woven material, a glass, a fiberglass, a ceramic, a polymer, a resin, a polymer, a fluorinated polymer, an epoxy resin, a polyester resin, a polyurethane, a polyester, a rubber, a polyimide, a polybenzimidazole, an aromatic polyamide, a modified phenolic resin, or a combination thereof.

Embodiment 42. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body is essentially free of a reducing agent.

Embodiment 43. The abrasive article of any one of embodiments 1, 2 and 3, wherein the bonded abrasive body has a ratio of the diameter to the thickness of at least about 10: 1, or at least about 20:1, or at least about 50: 1, or at least about 100: 1; and wherein the bonded abrasive body has a ratio of the diameter to the thickness of not greater than about 10,000:1, or not greater than 5,000: 1.

Embodiment 44. The abrasive article of any one of embodiments 1, 2 and 3, wherein the abrasive article has a generally similar wear rate to the same abrasive article except without the impartation of color.

Embodiment 45. The abrasive article of any one of embodiments 1, 2 and 3, wherein the abrasive article has a generally similar material removal rate to the same abrasive article except without the impartation of color.

Embodiment 46. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising: forming a mixture comprising abrasive particles dispersed within a bond material; and curing the mixture at a temperature of at least 200°C in a non-oxidizing atmosphere to form a bonded abrasive body. Embodiment 47. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising: forming a mixture comprising abrasive particles dispersed within a phenyl-formaldehyde based bond material; and curing the mixture, wherein the bonded abrasive body has color defined by the CIELAB color system of an L* in a range of from 20 to 80; AND an a* of greater than 20 or less than about -20 and a b* in a range of from about -256 to about 256; OR a b* of greater than about 20 or less than about - 20 and an a* in a range of from about -256 to about 256.

Embodiment 48. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising: forming a mixture comprising abrasive particles dispersed within a bond material; and curing the mixture at a temperature of at least 200°C in a non-oxidizing atmosphere to form a bonded abrasive body wherein the bonded abrasive body has color defined by the CIELAB color system of an L* in a range of from 20 to 80; AND an a* of greater than 20 or less than about -20 and a b* in a range of from about -256 to about 256; OR a b* of greater than about 20 or less than about -20 and an a* in a range of from about -256 to about 256.

Embodiment 49. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising: forming a mixture comprising abrasive particles dispersed within a phenyl-formaldehyde based bond material; and curing the mixture, wherein the bonded abrasive body has substantially the same color before and after curing.

Embodiment 50. The method of any of embodiments 46, 47, 48 and 49, wherein forming the mixture comprises: coating the abrasive particles with a first resin; adding a second resin to the mixture, wherein the second resin is distinct from the first resin.

Embodiment 51. The method of any of embodiments 46, 47, 48 and 49, wherein forming the mixture comprises: coating the abrasive particles with a mixture of the first resin and a solvent; wherein the pigment and the first resin are soluble with the solvent.

Embodiment 52. The method of any of embodiments 46, 47, 48 and 49, wherein the novolac resin comprises a hardener comprising hexamethylenetetramine (HMTA).

Embodiment 53. The method of any of embodiments 46, 47, 48 and 49, wherein the bond material includes a significant amount of methylene and dimethylene amino crosslink bridges.

Embodiment 54. The method of any of embodiments 46, 47, 48 and 49, wherein the non-oxidizing atmosphere consists essentially of an inert gas.

Embodiment 55. The method of any of embodiments 46, 47, 48 and 49, wherein the non-oxidizing atmosphere consists essentially of an inert gas comprising nitrogen. Embodiment 56. The method of any of embodiments 46, 47, 48 and 49, wherein the non-oxidizing atmosphere consists essentially of nitrogen.

Embodiment 57. The method of any of embodiments 46, 47, 48 and 49, wherein curing the mixture comprises curing the mixture at a temperature of at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, or even at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C.

Embodiment 58. The method of any of embodiments 46, 47, 48 and 49, wherein curing the mixture comprises preventing the mixture from oxidizing during curing.

Embodiment 59. The method of any of embodiments 46, 47, 48 and 49, wherein the bond material is essentially free of an acrylate.

Embodiment 60. The method of any of embodiments 46, 47, 48 and 49, wherein the bond material has a glass transition temperature of at least at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, or even at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C.

Embodiment 61. The method of any of embodiments 46, 47, 48 and 49, wherein the bond material comprises a glass transition temperature of not greater than 350°C, not greater than 320°C or at least 300°C.

Embodiment 62. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a bond material content of at least about 5 wt.% based on the total weight of the body, and wherein the bonded abrasive body has a bond material content of not greater than about 80 wt.% based on the total weight of the body.

Embodiment 63. The method of any of embodiments 46, 47, 48 and 49, wherein the first resin is a resole.

Embodiment 64. The method of any of embodiments 46, 47, 48 and 49, wherein the first resin is a phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of greater than one.

Embodiment 65. The method of any of embodiments 46, 47, 48 and 49, wherein the first resin is a base-catalyzed resin.

Embodiment 66. The method of any of embodiments 46, 47, 48 and 49, wherein the second resin comprises a novolac resin. Embodiment 67. The method of any of embodiments 46, 47, 48 and 49, wherein the second resin is a phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of less than one.

Embodiment 68. The method of any of embodiments 46, 47, 48 and 49, wherein the second resin is an acid-catalyzed resin.

Embodiment 69. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a content of the second resin of at least about 5 wt.%, at least about 8 wt.%, at least about 10 wt.%, or at least about 12 wt.% based on the total weight of the bonded abrasive body; and wherein the bonded abrasive body has a content of the second resin of not greater than about 90 wt.%.

Embodiment 70. The method of any of embodiments 46, 47, 48 and 49, wherein the bond material includes a significant amount of methylene and dimethylene amino crosslink bridges.

Embodiment 71. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises a pigment.

Embodiment 72. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises an organic pigment.

Embodiment 73. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises a pigment having a thermal stability of at least about 150°C, at least about 155°C, at least about 160°C, at least about 165°C, at least about 170°C, at least about 175°C, at least about 180°C, at least about 185°C, or even at least about 190°C, at least about 195°C, at least about 200°C, at least about 205°C, at least about 210°C, at least about 215°C, at least about 220°C, or even at least about 225°C.

Embodiment 74. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises a pigment that is soluble in an aqueous solvent.

Embodiment 75. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises an inorganic pigment.

Embodiment 76. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has an abrasive particle content of at least about 5 wt.% based on the total weight of the body, and wherein the bonded abrasive body has an abrasive particle content of not greater than about 50 wt.% based on the total weight of the body.

Embodiment 77. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler that is distinct from the abrasive particles. Embodiment 78. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler in the form of powders, granules, spheres, fibers, or a combination thereof.

Embodiment 79. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler comprising an inorganic material.

Embodiment 80. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler comprising an organic material.

Embodiment 81. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler disposed within the bond material.

Embodiment 82. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body further comprises a filler comprising nepheline syenite, sand, bubble alumina, bauxite, chromites, magnesite, dolomites, bubble mullite, borides, titanium dioxide, carbon products, flour, clay, talc, hexagonal boron nitride, molybdenum disulfide, feldspar, glass spheres, glass fibers, CaF₂, KBF₄, Cryolite (Na3AlF₆), potassium Cryolite (K₃A1F₆) , pyrites, ZnS, copper sulfide, mineral oil, fluorides, carbonates, calcium carbonate, or a combination thereof.

Embodiment 83. The method of any one of the preceding embodiments, wherein the bonded abrasive body further comprises a filler comprising an antistatic agent, a metal oxide, a lubricant, a porosity inducer, coloring agent, and a combination thereof and wherein the filler is distinct from the abrasive particles.

Embodiment 84. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a filler content of at least about 1 wt.% based on the total weight of the body, and wherein the bonded abrasive body has a filler content of not greater than about 30 wt.% based on the total weight of the body.

Embodiment 85. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body is essentially free of a black filler.

Embodiment 86. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a porosity of at least about 1 vol.% based on the total volume of the body, and wherein the bonded abrasive body has a porosity of not greater than about 50 vol.% based on the total volume of the body.

Embodiment 87. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a diameter (D) extending radially across the body and a thickness (t) extending axially across the body, wherein the body comprises a ratio of the diameter to the thickness of at least about 10:1, at least about 20:1, at least about 50:1, or at least about 100:1.

Embodiment 88. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a color after curing defined by the CIELAB color system of:

a L* in a range of 20 to 80, 30 to 75, or even 35 to 75;

Embodiment 89. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a generally green color after curing defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* of less than about -20; and a b* in a range of from -256 to 256.

Embodiment 90. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a generally red color after curing defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* of at least about 20 and a b* in a range of from -256 to 256.

Embodiment 91. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a generally orange color after curing defined by the CIELAB color system of a L* in a range of from about 20 to about 80; an a* in a range of at least about 20 and a b* of at least about 20.

Embodiment 92. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a generally yellow color after curing defined by the CIELAB color system of a L* in a range of from about 20 to about 80; a b* in a range of at least about 20 and an a* in a range of from -256 to 256.

Embodiment 93. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has a generally green color after curing defined by the CIELAB color system of a L* in a range of from 20 to 80; an a* of not greater than -20; and a b* in a range of from -256 to 256.

Embodiment 94. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body comprises a reinforcing layer extending radially through at least a portion of the body, wherein the reinforcing layer comprises a reinforcing material comprising a fabric, a fiber, a film, a woven material, a non-woven material, a glass, a fiberglass, a ceramic, a polymer, a resin, a polymer, a fluorinated polymer, an epoxy resin, a polyester resin, a polyurethane, a polyester, a rubber, a polyimide, a polybenzimidazole, an aromatic polyamide, a modified phenolic resin, or a combination thereof.

Embodiment 95. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body is essentially free of a reducing agent.

Embodiment 96. The method of any of embodiments 46, 47, 48 and 49, wherein the bonded abrasive body has ratio of the diameter to the thickness is be at least about 10: 1, at least about 20:1, at least about 50: 1, or at least about 100: 1; and wherein the bonded abrasive body has a ratio of the diameter to the thickness of not greater than about 10,000:1, or not greater than 5,000: 1.

Embodiment 97. The method of any of embodiments 46, 47, 48 and 49, wherein the abrasive article has a generally similar wear rate to the same abrasive article except without the impartation of color.

Embodiment 98. The method of any of embodiments 46, 47, 48 and 49, wherein the abrasive article has a generally similar material removal rate to the same abrasive article except without the impartation of color.

EXAMPLES

The concepts described herein will be further described in the following Examples, which do not limit the scope of the invention described in the claims.

Example 1 - Uncured Sample Abrasive Wheels

Uncured comparison sample abrasive wheels UCS1, UCS2, UCS3 and UCS4 were prepared having compositions as shown in Table 1 below:

TABLE 1 - Uncured Comparison Sample Abrasive Wheel Compositions

Color characteristics for each of the uncured comparison sample abrasive wheels

UCS1, UCS2, UCS3 and UCS4 were observed visually and quantified using the CIE L*a*b* color system as described herein. A summary of these color characteristics for each uncured comparison sample abrasive wheels is provided in Table 2 below:

TABLE 2 - Uncured Comparison Sample Abrasive Wheel Color Characteristics

Example 2— Oxygen Cured Sample Abrasive Wheels

Comparison sample abrasive wheels CS1, CS2 and CS3 were prepared having compositions as shown in Table 3 below and cured in a standard oxygen atmosphere.

TABLE 3— Oxygen Cured Comparison Sample Abrasive Wheel Compositions

Color characteristics for each of the cured comparison sample abrasive wheels CS1,

CS2 and CS3 were observed visually and quantified using the CIE L*a*b* color system described herein. A summary of these color characteristics for each oxygen cured comparison sample abrasive wheels is provided in Table 4 below: TABLE 4 - Oxygen Cured Comparison Sample Abrasive Wheel Color

Characteristics

As can been seen by comparing the color characteristics of uncured sample abrasive wheels UCS1, UCS2, UCS3 and UCS4 (see Table 2) and the color characteristics of oxygen cured sample abrasive wheels CS1, CS2 and CS3 (see Table 4), the color of the uncured abrasive wheels changes from the combined color of any pigments in the wheel and the yellow color of the resin to black or dark brown after being cured in a standard oxygen atmosphere. Without wishing to be bound by any one theory, it is believed that the original yellow color of the resin in the abrasive wheels deteriorates during conventional curing procedures in a standard oxygen atmosphere leading to discoloration that obscures the color of the pigments and results in black or dark brown abrasive wheels.

Example 3— Inert Atmosphere Cured Sample Abrasive Wheels

Sample abrasive wheels SI, S2, S3, S4 and S5 formed according to embodiments described herein were prepared having compositions as shown in Table 5 below and cured in an inert atmosphere of nitrogen gas.

TABLE 5 - Inert Atmosphere Cured Sample Abrasive Wheel Compositions

Color characteristics for each of the inert atmosphere cured sample abrasive wheels

SI, S2, S3, S4 and S5 were observed visually and quantified using the CIE L*a*b* color system as described herein. A summary of these color characteristics for each inert atmosphere cured sample abrasive wheels is provided in Table 6 below:

TABLE 6 - Inert Atmosphere Cured Sample Abrasive Color Characteristics

As can been seen by comparing the color characteristics of uncured sample abrasive wheels UCS1, UCS2, UCS3 and UCS4 (see Table 2) and the color characteristics of inert atmosphere cured sample abrasive wheels SI, S2, S3, S4, and S5 formed according to embodiments described herein (see Table 6), the original color of the uncured abrasive wheels provided from the color of any pigments in the wheel in combination with the yellow color of the resin is maintained with minimal color change after being cured in an inert atmosphere (i.e. nitrogen) according to embodiments described herein. Without wishing to be bound by any one theory, it is believed that the original yellow color of the resin in the abrasive wheels does not deteriorate when cured in an inert atmosphere leading to minimal or no discoloration, which therefore does not obscure the color of any pigments in the abrasive wheels.

Example 4— Grinding Performance

Sample abrasive wheels were prepared having compositions COMP1, COMP2 and COMP3 as shown in Table 7 below:

TABLE 7— Abrasive Wheel Compositions for Grinding Performance Testing

Sample abrasive wheels for each composition (COMP1, COMP2 and COMP3) were prepared and cured in a standard oxygen atmosphere with a 185 °C soak (hereinafter "185- O"). Sample abrasive wheels for each composition (COMP1, COMP2 and COMP3) were also prepared and cured in an inert atmosphere of nitrogen with a 185 °C soak (hereinafter "185-AC"). Sample abrasive wheels for each composition (COMP1, COMP2 and COMP3) were also prepared and cured in an inert atmosphere of nitrogen with a 195 °C soak

(hereinafter "185-AC").

The material removal rate (MRR) achieved by each sample abrasive wheel. The mean MRR for all three abrasive wheels formed using 185-0 was calculated and recorded. The mean MRR for all three abrasive wheels formed using 185-0 was also calculated and recorded. The mean MRR for all three abrasive wheel formed using 185-0 was also calculated and recorded. A summary of these MRR results is provided in Table 8 below: TABLE 8 -Abrasive Wheel Grinding Performance - MRR

The wheel wear rate (WWR) achieved by each sample abrasive wheel. The mean WWR for all three abrasive wheels formed using 185-0 was calculated and recorded. The mean WWR for all three abrasive wheels formed using 185-0 was calculated and recorded. The mean WWR for all three abrasive wheels formed using 185-0 was calculated and recorded. A summary of these WWR results is provided in Table 9 below:

TABLE 9 -Abrasive Wheel Grinding Performance - WWR

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Separate embodiments may also be provided in combination in a single embodiment, and conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

Claims

WHAT IS CLAIMED IS:

1. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising:

forming a mixture comprising abrasive particles dispersed within a bond material; and

curing the mixture at a temperature of at least 185°C in a non-oxidizing atmosphere to form a bonded abrasive body.

2. A method of forming an abrasive article comprising a bonded abrasive body, the method comprising:

forming a mixture comprising abrasive particles dispersed within a phenyl- formaldehyde based bond material; and

curing the mixture,

wherein the bonded abrasive body has substantially the same color before and after curing.

3. The method of any of claims 1 and 2, wherein the bond material includes a

significant amount of methylene and dimethylene amino crosslink bridges.

4. The method of any one of claims 1 and 2, wherein the non-oxidizing atmosphere consists essentially of an inert gas.

5. The method of any one of claims 1 and 2, wherein the non-oxidizing atmosphere consists essentially of an inert gas comprising nitrogen.

6. The method of any one of claims 1 and 2, wherein the non-oxidizing atmosphere consists essentially of nitrogen.

7. The method of any one of claims 1 and 2, wherein the bond material is

essentially free of an acrylate.

8. An abrasive article comprising:

a bonded abrasive body comprising abrasive particles contained within a bond material, wherein the bond material has a glass transition temperature of at least about 200°C; and wherein the bonded abrasive body is color stable.

9. An abrasive article comprising:

a bonded abrasive body comprising abrasive particles contained within a bond material, wherein the bond material has a glass transition temperature of at least about 200°C, and wherein the bond material has a color defined by the CIELAB color system of an L* in a range of from 20 to 80; AND an a* of greater than 20 or less than about -20 and a b* in a range of from about -256 to about 256; OR a b* of greater than about 20 or less than about -20 and an a* in a range of from about -256 to about 256.

10. The abrasive article of any one of claims 8 and 9, wherein the bond material is essentially free of an acrylate.

11. The abrasive article of any one of claims 8 and 9, wherein the bonded abrasive body has a bond material content of at least about 5 wt.% based on the total weight of the body.

12. The abrasive article of any one of claims 8 and 9, wherein the bond material comprises a cured and cross-linked reaction product of a first resin and a second resin distinct from the first resin.

13. The abrasive article of any one of claims 8 and 9, wherein the bonded abrasive body comprises a pigment.

14. The abrasive article of any one of claims 8 and 9, wherein the bonded abrasive body comprises an organic pigment.

15. The abrasive article of any one of claims 8 and 9, wherein the bonded abrasive body comprises a pigment having a thermal stability of at least about at least about 180°C.