ABRASIVE ARTICLE AND METHOD OF USE

Abstract

A coated abrasive article (10) having a flexible backing (12) and an abrasive coat (20) attached to the backing (12) by a tie coat (18), wherein the tie coat (18) is liquid-softenable such that the tie coat (18) maintains the flexible backing (12) in a substantially rigid state when the tie coat (18) is dry and allows the backing (12) to flex when the tie coat (18) is in its softened state.

Claims

1. A coated abrasive article having a flexible backing and an abrasive coat attached to the backing by a tie coat, wherein the tie coat is liquid-softenable such that the tie coat maintains the flexible backing in a substantially rigid state when the tie coat is dry and allows the backing to flex when the tie coat is in its softened state.

2. The article of claim 1 wherein the tie coat is a hydrogel.

3. The article of claim 2 wherein the tie coat contains an acrylol morpholine oxide UV-curable monomer.

4. The article of claim 1 wherein the backing is a non-woven web or foam.

5. The article of claim 4 wherein the backing is a thermoplastic web.

6. The article of claim 1 wherein the abrasive coat comprises a cured abrasive slurry containing a plurality of abrasives particles, wherein the abrasive slurry is soluble such that it retains the abrasive particles on the backing when in its solid state, and releases the abrasive particles from the backing during the process of dissolution to a dissolved state.

7. The article of claim 6 wherein the abrasive slurry is a UV light cured abrasive slurry.

8. The article of claim 7 wherein the slurry dissolves into a polishing compound upon activation by liquid.

9. The article of claim 1 wherein the liquid is water.

10. The article of claim 6 wherein the cured undissolved slurry has a surface texture comprising geometric forms.

11. The article of claim 10 wherein the geometric forms are polygons.

12. The article of claim 6 wherein the abrasive particles are formed of vermiculite, alumina or silicon carbide, preferably of alumina.

13. A method of abrading a work piece, the method including the steps of: providing a coated abrasive article having a flexible backing and an abrasive coat attached to the backing by a tie coat, wherein the tie coat is liquid-softenable such that the tie coat maintains the flexible backing in a substantially rigid state when the tie coat is dry and allows the backing to flex when the tie coat is in its softened state, the method including the further steps of: applying a liquid to the article to soften the tie coat, abrading the work piece.

14. The method of claim 13 wherein the method includes the step of: abrading the work piece with the article in a dry state prior to adding the liquid.

Description

[0035] FIG. 1 shows an abrasive article in the form of an abrasive disc 10. The disc 10 is suitable for mounting on a rotary polisher or random orbital sander although it is conceivable within the scope of the invention that the abrasive article could be used for other forms of abrasive work. The disc 10 has a backing 12 with first and second opposed major surfaces 14, 16. The first major surface 14 carries a tie coat 18. An abrasive coat 20 is positioned on the tie coat 18.

[0036] The backing 12 is formed of a non-woven thermoplastic web comprising an open, lofty, three-dimensional structure of fibers bonded to one another at their mutual contact points. Such non-woven backings are well known in the art. In an alternative embodiment the backing 12 is a foam backing and other forms of backing are conceivable within the scope of the invention. The backing material, whether non-woven or foam, is flexible so as to offer a degree of compliance to the abrasive disc 10 when wet as will be described in further detail below.

[0037] The tie coat 18 serves two principal purposes. Firstly, it improves the adhesion of the abrasive coat 20 to the backing and secondly it provides a degree of control over the rigidity of the backing 12. As described above, the backing 12 is inherently flexible. However, the process of UV-curing the tie coat 18 on the backing hardens the tie coat 18 which then maintains the backing 12 in a rigid state despite its inherent flexibility. This rigidity is maintained until such time as the tie coat 18 comes into contact with water (or other liquid such as an emulsion or surfactant) at which point the tie coat 18 softens. This has two effects. Firstly, the tie coat 18 no longer maintains the backing 12 in a rigid state allowing the adhesive disc 10 to adopt a degree of compliance. This reduces the aggression of the cut of the abrasive disc 10. Secondly, the tie coat permits a degree of movement in the abrasive coat 20 which further reduces the aggression of the cut.

[0038] The tie coat 18 contains an acrylol morpholine oxide UV-curable monomer which has a high glass transition temperature, is very hard when dry but is water-soluble in its cured linear polymer form. This solubility allows the tie coat 18 (and thereby the backing 12 to which the tie coat 18 is adhered) to transition from rigid when dry to flexible when wet.

[0039] The abrasive coat 20 is formed of a UV-curable abrasive slurry which contains a plurality of abrasive particles. The abrasive particles in this embodiment are Alumina 5 m or Alumina 14 m although other suitable minerals fall within the scope of the invention. The slurry is cast into a micro-replicated tooling to form a structured abrasive once cured. This process generates a geometric surface texture on the abrasive article in the form of polygons 22. When the abrasive disc 10 is dry, the abrasive coat 20 (by way of the polygons 22) delivers aggressive cut as the tips of the polygons abrade the workpiece.

[0040] However, the abrasive slurry, like the tie coat 18 described above, contains acrylol morpholine oxide (also referred to as ACMO) which enables the abrasive slurry to dissolve upon contact with water. Thus, the addition of water to the abrasive disc 10 causes the aggressive polygons to soften and break up. This reduces the cut of the abrasive article and increases the finish. As the dissolution continues the small abrasive particles (Alumina in the range of 5 to 14 um) are freed resulting in the abrasive slurry dissolving into a polishing compound which delivers a high finish to the workpiece.

Tie Coat Formulation Example 1

[0041]

TABLE-US-00001 Component % age by Weight ACMO 83.6 SR-246 1.2 TPO-L 2.8 OX-50 12.6 Total 100

Tie Coat Formulation Example 2

[0042]

TABLE-US-00002 Component Mass (g) ACMO 92.7 SR-259 1.4 Klucel G 2.7 TPO-L 3.2 Total 100.0

Abrasive Coat Formulation Example 1

[0043]

TABLE-US-00003 Addition 50% 5 um mix order (% age by Weight) Notes Isopar V A 11.3 Hydrocarbon Solvent to assist cut lubrication Drakesol A Hydrocarbon Solvent to assist cut lubrication 305 M120 B 1.7 Assists the formulation of micelles lauryl acrylate ACMO E 30.9 Acrylol morpholine oxide soluble monomer Byk UV- D 0.4 Oil emulsifier to promote mineral dispersal 3500 Byk W985 F 4.3 Oil emulsifier to promote mineral dispersal Alumina 5 m G 49.8 Abrasive Mineral TPO-L H 1 Catalyst for UV curing R812 C 0.7 Thickener for solvent to promote stabilization of fumed micelles silica Total 100

Abrasive Coat Formulation Example 2

[0044]

TABLE-US-00004 Addition 50% 14 um mix order (% age by Weight) Notes Isopar V A 11.2 Hydrocarbon Solvent to assist cut lubrication Drakesol 305 A Hydrocarbon Solvent to assist cut lubrication M120 lauryl B 1.7 Assists the formulation of micelles acrylate ACMO E 30.6 Acrylol morpholine oxide soluble monomer Byk UV-3500 D 0.4 Oil emulsifier to promote mineral dispersal Byk W985 F 5.1 Oil emulsifier to promote mineral dispersal Alumina 14 m G 49.1 Abrasive Mineral TPO-L H 0.05 Catalyst for UV curing R812 fumed C 0.04 Thickener for solvent to promote stabilization of silica micelles Total 100

Abrasive Coat Formulation Example 3

[0045]

TABLE-US-00005 Component Mix order Mass (g) Drakesol 305 A 505.08 Parol 70 B 365.12 R812 fumed C 42.6 silica Byk UV-3500 D 27.38 ACMO E 1831.68 M120 lauryl F 152.13 acrylate Byk W985 G 261.67 Irgacure 819 H 49.6 Alumina 14 I 1521.33 um 783-C OX50 fumed J 243.41 silica Total 5000
Curing was achieved in a two stage process with the tie coat being cured before application and curing of the abrasive slurry.