Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1998-06-30
2001-07-17
Thibodeau, Paul (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S411100, C428S413000, C428S422800, C428S423100, C428S425100, C428S480000, C428S481000, C428S500000, C428S511000, C428S524000, C428S530000, C051S298000, C051S304000
Reexamination Certificate
active
06261682
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to abrasive articles including an antiloading composition. In particular, abrasive articles in accordance with the invention are useful in abrading the surface of metal, metal alloys, glass, wood, paint, plastics, body filler, primer, etc. Also included are methods for making and methods of using abrasive articles.
BACKGROUND OF THE INVENTION
In general, coated abrasive products are known to have abrasive particles adherently bonded to a flexible backing. It is generally known to stratify the abrasive particles and binders, such as in coated abrasive articles, in such a way as to basically segregate the abrasive particles between an underlying binder and an overlaying binder.
More typically, abrasive products have a backing, abrasive particles, and a binder which operates to bond or hold the abrasive particles to the backing. For example, a typical coated abrasive product has a backing that is first coated with a binder, commonly referred to as a “make coat”, and then the abrasive particles are applied to the make coat. The application of the abrasive particles to the make coat typically involves electrostatic deposition or a mechanical process which maximizes the probability that the individual abrasive particles are positioned with their major axis oriented perpendicular to the backing surface. As so applied, the abrasive particles optimally are at least partially embedded in the make coat that is then generally solidified or set (such as by a series of drying or curing ovens) to a state sufficient to retain the adhesion of abrasive particles to the backing.
Optionally, after precuring or setting the make coat, a second binder, commonly referred to as a “size coat”, can be applied over the surface of the make coat and abrasive particles, and, upon setting, it further supports the particles and enhances the anchorage of the particles to the backing. Further, a “supersize” coat, which may contain grinding aids, anti-loading materials or other additives can be applied over the cured size coat. In any event, once the size coat and supersize coat, if used, has been cured, the resulting coated abrasive product can be converted into a variety of convenient forms such as sheets, rolls, belts, and discs.
Coated abrasives are used to abrade a variety of workpieces including metal, metal alloys, glass, wood, paint, plastics, body filler, primer, etc. In abrading certain workpieces, for example, wood, paint, body filler, primer, and plastics, the coated abrasive has a tendency to “load.” “Load” or “loading” are terms used in the industry to describe the debris, or swarf, that is abraded away from the workpiece surface that subsequently becomes lodged between the abrasive particles of the abrasive article. Loading is generally undesirable because the debris lodged between abrasive particles inhibits the cutting ability of the abrasive article.
One solution to the loading problem is to apply a coating to an abrasive article so that it is available at the interface between the abrasive article and the workpiece surface to inhibit loading. For example, U.S. Pat. No. 2,768,886 (Twombly et al.) and U.K. Patent No. 712,718 each describe a metal stearate or palmitate applied to the surface of an abrasive article. U.S. Pat. Nos. 2,893,854 and 3,619,150 (both to Rinker et al.) each describe a metallic water-insoluble soap of a saturated fatty acid having from 16 to 18 carbon atoms that is applied to an abrasive article. U.S. Pat. No. 4,396,403 (Ibrahim) describes an abrasive article including a coating containing a material selected from the group consisting of phosphoric and condensed phosphoric acids and partial esters, including amine salts thereof, tetraorganyl ammonium salts having at least one long organyl group containing at least eight carbon atoms, and mixtures thereof. Other materials that have been applied to an abrasive article include, for example, a quaternary ammonium salt having from about 15 to about 35 carbon atoms (U.S. Pat. No. 4,973,338 to Gaeta et al.) and a lithium salt of a saturated fatty acid having 4 to 22 carbon atoms (U.S. Pat. No. 4,988,554 to Peterson et al.). Other antiloading components are also described by Law et al. in U.S. Pat. Nos. 5,667,542 and 5,704,952.
SUMMARY OF THE INVENTION
Thus, what is desired in the industry is a load resistant coating for abrasive articles that can be used under relatively low abrading pressures typically useful in abrading relatively soft surfaces, such as plastics, paint, etc.
Preferably, an abrasive article in accordance with the present invention includes a peripheral coat comprising an antiloading component of the formula: (C
n
H
2n+1
)—COO—M, wherein n is greater than7 and M is selected from Group 1 of the Periodic Table, with the proviso that when M is lithium, n is greater than 21.
The term “peripheral coat”, as used herein, refers that portion of a coating on an abrasive article present on at least a portion of a surface of the abrasive article, typically over and in between at least a portion of the plurality of abrasive particles, that is capable of contacting and abrading the surface of a workpiece by the abrasive article.
One aspect of the present invention provides an abrasive article including a backing having a first major surface and a second major surface; a plurality of abrasive particles; and a binder which adheres the plurality of abrasive particles to the first major surface of the backing. Also included is a peripheral coat comprising an antiloading component of the formula: (C
n
H
2n+1
)—COO—M, wherein n is greater than 17 and M is selected from Group 1 of the Periodic Table, with the proviso that when M is lithium, n is greater than 21. In one embodiment, the binder is a make coat and the abrasive article may further include a size coat. Additionally, the abrasive particles may be dispersed within the binder forming an abrasive coating on the first major surface of the backing. The peripheral coating may further include a binder.
In any case, the binder included in an abrasive article in accordance with the present invention is formed from a binder precursor selected from the group of a phenolic resin, an aminoplast resin having pendant &agr;,&bgr;-unsaturated carbonyl groups, a urethane resin, an epoxy resin, a urea-aldehyde resin, an isocyanurate resin, a melamine-aldehyde resin, an acrylate resin, an acrylated isocyanurate resin, an acrylated urethane resin, an acrylated epoxy resin, a bismaleimide resin, a polyester resin, and a mixture thereof.
Preferably, the antiloading component is present in the peripheral coating in an amount of about 50 weight percent to about 100 weight percent based on a total weight percent of the peripheral coating.
Another aspect of the present invention provides a method of making an abrasive article including the steps of providing a backing having at least one major surface; applying a make coat binder precursor over the at least one major surface of the backing; and applying a plurality of abrasive particles to the make coat binder precursor. Also included is the step of applying a size coat binder precursor over the make coat binder precursor and the plurality of abrasive particles; and at least partially curing the make coat binder precursor and the size coat binder precursor to form a make coat and a size coat, respectively. The method also includes the step of applying peripheral coating composition over at least a portion of the size coat, wherein the peripheral coating composition comprises an antiloading component of the formula (C
n
H
2n+1
)—COO—M, wherein n is greater than 17 and M is selected from Group 1 of the Periodic Table, with the proviso that when M is lithium, n is greater than 21.
Preferably, the peripheral coating composition further comprises a liquid medium, wherein the liquid medium can be selected from the group of an organic solvent based medium, an aqueous based medium, and a mixture thereof More preferably, the peripheral coating composition comprises a dispersion of the antiloading c
3M Innovative Properties
Allen Gregory D.
Rickman Holly C.
Thibodeau Paul
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