Abrasive articles, rotationally reciprocating tools, and methods

(54) Title: ABRASIVE ARTICLES, TOOLS (57) Summary:

RECIPROCANTS OF ROTARY FORM AND

METHODS (30) Unionist Priority: 3/21/2007 us 11 / 689,250 (73) Owner (s): 3M Innovative Properties Company (72) Inventor (s): Michael J. Annen, Peter A. Felipe, Sr.

(74) Attorney (s): NELLIE ANNE DAIEL-SHORES (86) International Request: pct 11Ξ2008057610 of 20/03/2008 (87) International Publication: wo 2008 / 116043de 25/09/2008

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132 ó “ABRASIVE ARTICLES, RECIPROCATING TOOLS OF ROTARY FORM AND METHODS”

In order to protect and preserve the aesthetic qualities of the finish of an automobile or other vehicle, it is common knowledge to provide a colorless (non-pigmented or slightly pigmented) final coat over a colored (pigmented) base coat, so that the base coat remains unchanged even during prolonged exposure to the environment or weathering. In general, the technique reveals finishes made with a base coat / final coat or colorless base / coat. Typically, the resulting finish is not completely smooth (due to, for example, spray conditions, the composition of the final coat or colorless coat, drying conditions, topography of the underlying surface, etc.). Rather than being completely smooth, the colorless or final coat typically has a texture that is somewhat similar to the texture seen on an orange peel. This texture is commonly called “orange peel” finish and is acceptable in most situations.

During the application of each of these coatings, or during their repair, dust, dirt or other particles can, however, get stuck in the finish, resulting in defects such as protuberances, etc. in finishing (commonly called “protuberances”). Defects typically impair the appearance of the orange peel finish to an unacceptable degree.

The removal of unacceptable defects (commonly referred to as "lump removal") is typically achieved by relatively aggressive abrasion methods, which affect areas of the surface that are significantly larger than the defect itself. As a result, the repairs themselves can cause flat marks in the appearance of orange peel characteristic of the areas adjacent to the removed defects. These flat spots on the orange peel texture may, in some cases, also be unacceptable. To avoid flat spots on the orange peel texture, a technician may even need to repair a complete panel of the structure, rather than repairing individual defects. Such extensive refinishing can significantly increase the time, energy and cost of removing or repairing defects such as lumps in a finish.

More generally, the same problems of mixing the appearance of the surface between the refinished and non-refinished areas on a surface can also appear in several other conventional abrasion processes, for example, processes involving coated abrasive products.

Summary of the Invention

The present invention presents methods of surface abrasion by reciprocating rotating abrasive surfaces in contact with the surfaces. The present invention can also provide abrasive articles for use in reciprocating rotary tools. In addition, the present invention can also provide methods of removing defects on a surface, where the method includes sanding (using a rotating reciprocating abrasive surface) followed by one or more polishing operations.

For use in the present invention, the term "rotational reciprocation" (and variations thereof) is used to describe the rotation of an abrasive article around an axis of rotation in alternating directions, clockwise and counterclockwise. In other words, the abrasive article is rotated first in a first direction around an axis of rotation, stopped, rotated in the opposite direction, stopped, etc.

Rotational reciprocating of abrasive articles can provide advantages in removing minor defects (for example, tips, protuberances, etc.) from a surface, compared to conventional processes involving, for example, rotating abrasive articles. These advantages may include, for example, reduced disturbance of any orange peel texture on the surface surrounding the defect, reduction in the number of steps required to complete the repair, reduction in the total area affected by the repair, etc.

Limiting the disturbance of the orange peel texture in the surface finish while still removing the defective surface can, in many instances, allow the removal of such defects without the need to treat the entire surface, to avoid introducing flat spots which are unacceptable in size and / or frequency in the orange peel texture.

Also among the potential advantages of the present invention is the opportunity to reduce the number of steps required to repair surface defects on, for example, a finished surface (where the finish is, for example, a colorless coat, a paint, a varnish , etc.). Conventional methods of removing such defects (sometimes called "lump removal" in the automotive industry) may require up to five steps to achieve an acceptable result. The conventional process typically includes: 1) sanding (to remove lumps), 2) scraping refinement (to remove more prominent sanding scratches), 3) composition (to further remove sanding scratches), 4) polishing (for polish the finish after steps 2 &amp; 3), and 5) swirl removal (to remove swirl marks left after polishing).

Due to the fact that sandpaper on tools used to perform sanding are typically larger (for example, with diameters in the range of 15.2 to 22.9 centimeters (6 to 9 inches)), the resulting areas where Steps 1 through 5 must also be carried out, as the size of the sandpaper makes it almost impossible to avoid affecting large areas of the surface from which defects are being removed. In some cases, it is economical to refinish all panels of the structure using the steps described above (especially where the orange peel texture in the finish has been removed over wide areas).

In contrast, the abrasive articles and rotary reciprocating tools of the present invention can provide the user with the ability to repair surface defects in a fraction of the time required for a conventional 5-step process. With the use of the present invention, defects can be repaired (with an impact limited to the orange peel texture) by sanding (rotating the abrasive articles and tools described here in a rotating manner) followed by one or more polishing operations . It may be preferable that sanding is followed by an initial polishing step, followed by at least one subsequent polishing operation to remove swirl marks left after the initial polishing operation. In other words, the conventional five-step process can be carried out in two or three steps.

In addition, due to the fact that the size of the affected area during the removal of each defect is relatively small, the disturbance of the orange peel texture around the defect is significantly reduced compared to defect removal techniques ( for example, lump removal) using wider conventional tools. As a result, the likelihood that the entire panel of the structure needs to be refinished due to the noticeable leveling of the orange peel around each of the defects can be significantly reduced.

To minimize the size of the affected area during the re-finishing process, it may be preferable to use abrasive articles with smaller abrasive surfaces, as described in the present invention. For example, it may be preferable to use abrasive surfaces with a size of about 500 square millimeters (mm²) or less, in some cases, about 300 mm² or less, or even about 150 mm² or less. However, with abrasive surfaces so small, conventional rotary sanding processes in which the abrasive surface is rotated at relatively high speeds will typically provide more energy than necessary to remove the defect. This excessive energy will also typically result in undesirable heat production, deeper scratches, and / or more aggressive removal of the material than necessary - especially in the removal of minor surface defects.

The rotary reciprocating of an abrasive article, as discussed in connection with the present invention, can, however, provide enough abrasive energy to remove the defect. However, the amount of abrasive energy is not very high, to the point that scratches and / or material removal are excessive. In other words, the scratches formed with the use of a reciprocating rotary tool may be more shallow than those that would be formed using a rotary sander. Shallow scratches may preferably require less extensive refinishing compared to more conventional sanding / refinishing methods.

The rate at which abrasive articles can be reciprocated can vary based on a variety of factors (for example, the surface being scraped, the size of the abrasive article, the desired rate of abrasion, etc.). It may be preferable that the reciprocation can be performed at a frequency of at least about 60 cycles per minute (ie, 1 Hertz) or greater (where a cycle is a change in the direction of rotation). In some cases, it may be preferable that the reciprocal frequency is 2 Hz or more, 100 Hz or more, 500 Hz or more, 1,000 Hz or more, or even 2,000 Hz or more.

In one aspect, the present invention can provide a method of abrasion of a workpiece surface. The method includes providing an abrasive article mounted on a motor tool shank, the abrasive article having an abrasive surface with abrasive particles attached to it, contact of the workpiece surface with the abrasive surface of the abrasive article, and rotatingly reciprocating the abrasive surface of the abrasive article around an axis of rotation, rotatingly reciprocating the motor tool shank, the workpiece surface being scraped by abrasive particles attached to the abrasive surface of the abrasive article, while the abrasive surface of the abrasive article is rotated reciprocally around the axis of rotation.

In another aspect, the present invention can provide a conformable abrasive article that includes a base plate that has a support surface, a resiliently compressible element fixed to the support surface of the base plate, the compressible element having a first surface main side facing the support surface and a second main surface facing the opposite side of the support surface, and the first main surface and the second main surface of the compressible element being the widest or widest than the support surface of the base plate, a flexible support layer fixed to the compressible element, the support layer having a first main surface facing the compressible element and a second main surface facing the opposite side of the compressible element, and the first main surface and the second main surface of the support layer being wider than the second main surface of the compressible element, and an abrasive element fixed to the second main surface of the support layer, such that an abrasive surface of the abrasive element is facing the opposite side of the compressible element and the base plate, and the abrasive surface having a flat abrasive surface that is coextensive with the second main surface of the support layer.

In another aspect, the present invention can provide an abrasive tool that includes a motor-equipped device that has an outlet rod adapted to rotate reciprocating around an axis of rotation, and an abrasive article with an abrasive surface that includes abrasive particles, the abrasive article being fixed to the exit rod, the rotational reciprocating of the exit rod rotatingly reciprocating the abrasive article around the axis of rotation.

In another aspect, the present invention can provide a method for repairing defects in a workpiece surface. The method includes sanding one or more defects on the surface of a workpiece, rotating reciprocally an abrasive surface of an abrasive article around an axis of rotation, using the rod of the power tool, the surface being the workpiece is scraped by abrasive particles attached to the abrasive surface of the abrasive article, while the abrasive surface of the abrasive article is rotated reciprocated around the axis of rotation, and polishing an area of ​​the workpiece surface that surrounds and contains one or more defects by contacting the workpiece surface with the sanding work surface, the sanding work surface being rotated in one direction around an axis of rotation that extends along the workpiece surface and the sanding work surface, an abrasive slurry being forced against the workpiece surface by the sanding work surface, and the abrasive slurry contains abrasive particles that are finer than the abrasive particles attached to the abrasive surface of the abrasive article.

In another aspect, the present invention can provide a method for repairing defects in a workpiece surface. The method includes sanding one or more defects on the surface of a workpiece, rotating reciprocally an abrasive surface of an abrasive article around an axis of rotation using the rod of the power tool, the surface of which is workpiece is scraped by abrasive particles attached to the abrasive surface of the abrasive article, while the abrasive surface of the abrasive article is rotated reciprocated around the axis of rotation, and the rotary reciprocating of the abrasive surface comprises reciprocating the abrasive surface at a frequency of 1 Hz or more. The method also includes polishing an area of ​​the workpiece surface that surrounds and contains one or more defects after sanding, placing the workpiece surface in contact with a sanding work surface, the sandpaper working surface rotates in a direction around a axis of rotation that extends along the workpiece surface and the work surface of the fixed, and with an abrasive slurry being forced against the workpiece surface by the sanding work surface, and the abrasive slurry containing abrasive particles that are finer than the abrasive particles attached to the abrasive surface of the article. The method also includes one or more subsequent polishing operations carried out in each surrounding area and containing one or more defects, with one or more subsequent polishing operations comprising contacting the workpiece surface with a work surface of the workpiece. sandpaper, the sandpaper working surface being rotated in a direction around an axis of rotation that extends along the workpiece surface and the sandpaper working surface, an abrasive slurry being forced against the workpiece surface by the sanding work surface, and the abrasive slurry used in each of the subsequent polishing operations contains abrasive particles that are finer than the abrasive particles contained in the abrasive slurry used in a previous polishing operation in the same area.

For use in the present invention, the term "resiliently compressible" (and variations thereof) means reducing in volume by at least 10%, in response to an applied compression force, and the compressed article recovering at least 50% of the reduced volume after removing the compression force within a minute or less.

For use in the present invention, the term "flat abrasive surface" means that the abrasive surface generically defines a plane (in the absence of some mechanical deformation force acting on the abrasive surface), such that, when applied to a flat surface of the part of work, rotation of the abrasive surface typically results in some contact between the abrasive surface and the workpiece surface over substantially the entire area of ​​the workpiece surface that faces the abrasive surface. It should be understood that a flat abrasive surface can include structures, particles, peaks and valleys, undulations, etc., in such a way that not the entire surface of the workpiece is in contact with the flat abrasive surface at all times. Additionally, such structures, particles, peaks and valleys, undulations, etc. they are not necessarily situated on the plane, but these characteristics will collectively define a plane over the entire abrasive surface (where the defined piano may have a limited thickness, in view of minor variations in the height of the characteristics that define the plane). Examples of some flat abrasive surfaces are shown in FIGURES 10A to 10C.

For use in the present invention, the term "fixed to" means directly fixed to, as well as fixed to an intervening component / layer. For example, the first and second components attached to each other may be in direct contact with each other or they may be attached to one or more intervening components / layers located between the first and second components.

For use in the present invention, the term “main surface” is used to refer to surfaces that define the thickness of an article - the term is typically used in connection with films, disc-shaped articles, etc., to refer to flat surfaces between which the thickness of the article is defined. For example, a sheet of paper includes two main surfaces and an edge surface extending between the two main surfaces.

This summary is not intended to describe each modality or all implementations of the present invention. Rather, a more complete understanding of the invention will become evident and will be appreciated by referring to the following Detailed Description of Exemplifying Modalities and claims, in view of the attached FIGURES.

Brief Description of Drawing Views

The present invention will be described, still, with reference to the attached drawings, being that:

FIGURE 1 is a side view of an exemplary motorized tool with an abrasive article attached to it.

FIGURE 2 is a side view of the power tool of FIGURE 1 with the abrasive article removed to expose the rotating reciprocating rod of the power tool.

FIGURE 3 is an enlarged end view of an exemplary abrasive surface in an exemplary abrasive article, which also illustrates an exemplary strip on which an abrasive surface can rotate reciprocally during use.

FIGURE 4 is an exploded view of an exemplary abrasive article in accordance with the present invention.

FIGURE 5 is a side view of an exemplary compressible unit article that incorporates a compressible element and a support layer.

FIGURE 6 is a side view of another exemplary compressible unitary article that incorporates a compressible element and a support layer.

FIGURES 7A and 7B represent a base plate and the base plate embedded in a compressible element.

FIGURE 8 represents an exemplary polishing pad and a work surface that can be used in connection with the invention's repair methods.

FIGURE 9 is a partial cross-sectional view of an exemplary polishing pad that has a converted work surface.

FIGURES 10A to 10C are schematic enlarged cross-sectional views of various types of abrasive layers that can be used in abrasive elements of the present invention.

Detailed Description of Exemplary Modalities of the Invention

In the following detailed description of illustrative modalities of the invention, a reference is made to the FIGURES attached to the drawings that form a part of this document, and in which specific modalities in which the invention can be practiced are shown, as an illustration. It should be understood that other modalities can be used and structural changes can be made without departing from the scope of the present invention.

FIGURE 1 represents an exemplary motorized tool 10 and an abrasive article 20 attached thereto, which can be used in connection with the present invention. FIGURE 2 represents the powered tool 10 with the abrasive article 20 removed, exposing a shank 12 extending out of the housing 14 of the powered tool 10. In some embodiments, the stem 12 can be partially protected by or enclosed within a housing (not shown) to protect the stem from damage if, for example, tool 10 is dropped, etc.

Although not shown in FIGURES 1 and 2, the motorized tool 10 may preferably include a motor, a transmission (if necessary), or a power supply (for example, batteries, etc.) within compartment 14, so so that the power tool 10 is a one-piece integral unit that does not need to be connected to an external power source, etc. In alternative embodiments, however, the power tool 10 may be able to connect to an external power source (i.e., a power source that is not contained within compartment 14) to provide the energy necessary to move the rod 12. Examples of some potentially suitable external power sources may be, for example, pneumatic lines, hydraulic lines, electrical power sources (for example, external batteries, power line voltages (for example, 120/220 Volt voltages, 60 Hz) , etc.).

The power tool 10 preferably produces a rotational reciprocating of the rod 12 around the axis of rotation 11. Rotational reciprocating of a rod can be provided by a variety of tools and mechanisms, some of which have been developed in connection with brush brushes. portable teeth equipped with motor. Examples of some potentially suitable motorized tools capable of providing rotational reciprocation are described, for example, in US patents No. 5,054,149 (Si-Hoe et al.), 5,311,633 (Herzog et al.), 5,822,821 (Sham ), etc. Although the abrasive surfaces used in connection with the invention may preferably be oriented perpendicular to the axis around which the rod 12 of the tool 10 rotates, the abrasive surfaces may alternatively have any orientation selected with respect to the axis 11 around which the rod 12 rotates. Examples of mechanisms capable of rotating a sandpaper reciprocally that is not perpendicular to the 11 axis can be found, for example, in US Patent No. 5,054,149 (Si-Hoe et al.), 5,311,633 (Herzog et al.), 5,822,821 (Sham), etc., and these mechanisms can be used in connection with the present invention.

The rotational reciprocating of the rod 12 preferably produces the corresponding rotational reciprocating of the abrasive article 20 attached or attached to the rod 12. FIGURE 3 is an enlarged end view of the abrasive article 20, with the axis of rotation 11 shown as if it were leaving the page (preferably, as shown, located in the center of the abrasive article). Rotational reciprocation causes the abrasive article 20 to rotate around the axis of rotation in a way that results in alternating clockwise and counterclockwise rotations around the axis of rotation 11.

It may be preferable that rotation in any direction is limited to a selected range or arc. An example of such an arc is shown in FIGURE 3 including an angle a (alpha) extending between points A and B on the periphery of the abrasive article 20. In some embodiments, the arc over which the abrasive article 20 rotates reciprocally it can be less than 360 degrees, 180 degrees or less, or even 90 degrees or less. The arc can be attached to any particular power tool 10, in such a way that the rod 12 rotates reciprocally over a given angular arc. Alternatively, the length of the reciprocating arc can be adjustable.

The reciprocal movement can have a frequency of at least about 60 cycles per minute or more (that is, 1 Hertz (Hz) or more) (where a cycle is a change in the direction of rotation). In some embodiments, the reciprocal frequency can be 2 Hz or more, 100 Hz or more, 500 Hz or more, 1,000 Hz or more, or even 2,000 Hz or more. In some cases, the arc and frequency of reciprocations may be related, for example, larger arcs may result in reduced frequencies, smaller arcs may result in higher frequencies, etc. The reciprocating frequency for any particular powered tool 10 can be fixed, although in some cases the user may be able to adjust the reciprocating frequency provided by the powered tool 10 (using, for example, a motor speed variable, etc.).

Although abrasive articles according to the present invention are represented in the present invention as having abrasive surfaces in the form of circular articles, abrasive articles can be manufactured in any other suitable shape, although shapes close to circles (e.g. hexagons, octagons) , decagons, etc.) may be preferred.

Abrasive articles in accordance with the present invention are useful for covering (including finishing) a workpiece where the workpiece can be manufactured from a variety of material types such as painted substrates (for example, which has a coat colorless, a base coat (color), an initiator or an e-initiator), coated substrates (eg with polyurethane, lacquer, etc.), plastics (thermoplastics, heat hardened), reinforced plastics, metal (low carbon steel, brass, copper, mild steel, stainless steel, titanium and the like), metal alloys, ceramics, glass, wood, wood-like materials, composites, stones (including precious stones), materials similar to stone, and combinations thereof. The workpiece can be flat or it can have a shape or contour associated with it. Examples of common workpieces that can be scraped by abrasive articles and methods of the invention include metal or wooden furniture, painted or unpainted surfaces for motor vehicles (car doors, hoods, trunk, etc.), plastic components automotive (headlight covers, rear light covers, other lamp covers, armrests, instrument panels, bumpers, etc.), floors (vinyl, stone, wood and wood-like materials), counters, and other plastic components.

During abrasion processes it may be desirable to supply a liquid to the surface of the workpiece and / or abrasive surface. The liquid can include water and / or an organic compound, and additives such as foam eliminators, degreasers, liquids, soaps, corrosion inhibitors, and the like.

As shown in FIGURES 1 and 2, it may be preferred that the abrasive article 20 is removably attached to the rod 12, such that the abrasive article 20 can be replaced after use. FIGURE 4 is an enlarged perspective view of an abrasive article 120 that can be used in connection with a power tool in the present invention.

Despite the fact that the abrasive article 120 shown includes a variety of components, as discussed in this document, a common component is a flat abrasive surface 172 arranged for use in connection with a power tool, as discussed here. The flat abrasive surface 172 can preferably be oriented in a normal way (i.e., orthogonal, perpendicular, etc.) to an axis of rotation 111 around which the abrasive surface is preferably rotated reciprocally during the use. In an abrasive article constructed from components with two opposite flat surfaces that are oriented parallel to each other (as shown in FIGURE 4), all the main surfaces of the components can also typically be oriented normally to the axis of rotation 111. It should be noted that these surfaces are preferably flat, in the absence of deformation by an external force acting on the abrasive article 120.

The abrasive article 120 shown includes an optional plug-in coupling 130 that supports a rigid base plate 140. The plug-in coupling 130 and the rigid base plate 140 can preferably be formed as a unitary molded article, despite the fact that that, in some embodiments, the coupling 130 can be separated from the base plate 140 with the two components fixed by any suitable connection technique.

Also shown in connection with the abrasive article 120 is an optional resiliently compressible element 150 attached to the support surface of the base plate 140. Although it is hidden by the compressible element 150 in FIGURE 4, it should be understood that the support surface of the base plate 140 is the main surface of the base plate 140 which faces the opposite side of the stem located in the coupling 130 and, correspondingly, which faces one of the main surfaces of the compressible element 150.

The abrasive article 120 of FIGURE 4 also includes an optional flexible support layer 160 attached to the compressible element 150 (despite the fact that, in the exploded view of FIGURE 4, the support layer 160 is disconnected from the compressible element 150). An abrasive element 170 with an abrasive surface 172 is attached to the main surface of the support layer 160 in such a way that the abrasive surface 172 faces away from the compressible element 150.

The plug-in coupling 130, as shown in FIGURE 4, can preferably include a hole 132 where the rod of a powered tool (not shown) is retained in such a way that the movement of the rod is transferred to the coupling 130 and the plate base 140 fixed to it. The orifice 132 can, for example, have a shape complementary to the shank of the powered tool, such that the rotational reciprocating movement is transferred from the shank to the plug-in coupling 130.

Although an example of a connection between the shank of a power tool and the abrasive article 120 is shown in connection with FIGURES 1, 2 and 4, it should be understood that any connection technique / apparatus capable of transferring the rotational reciprocating movement can be used in place of the one shown. Examples of alternative connections may include, for example, friction fitting components, threaded couplings, claws, etc.

Despite the fact that the replacement of the entire abrasive article 120 may be preferred in some embodiments of the invention, in other embodiments the base plate 140 can be fixedly attached to the shank of the power tool, with the replacement of the abrasive surface 172 being achieved by replacing other components in the system. For example, the compressible element 150 can be removably attached to the base plate 140, and the replacement of the abrasive surface 172 would be accompanied by replacement of the support layer 160 and the compressible element 150. In yet another alternative, the element compressible 150 can be fixedly attached to the base plate 140, such that replacement of the abrasive surface 172 is achieved by removing the support layer 160 from the compressible element 150. In such an embodiment, the compressible element 150 would remain attached to the base plate 140. In yet another alternative, the replacement of the abrasive surface 172 can be achieved by removing the abrasive element 170 itself from the support layer 160.

Numerous different techniques can be used to removably attach different components of the 120 pm abrasive article to each other, to provide different options for placing the abrasive surface 172 discussed above. Examples of some potentially suitable fastening systems may include, for example, adhesives, mechanical fastening systems (for example, hook and loop fasteners, etc.), etc. Examples of some potentially suitable fastening systems are described, for example, in US patents No. 3,562,968 (Johnson et al.), 3,667,170 (Mackay, Jr.), 3,270,467, 3,562,968 (Block et al .), and 5,672,186 (Chesley et al.), in US Patent Application Publication No. 2003/0143938 (Braunschweig et al.), and in US Patent Application Serial No. 10 / 828,119 (Fritz et al. .), filed on April 20, 2004.

It is preferred that most (if not all) abrasive surface 172 of abrasive article 120 can be kept in contact with the surface of a workpiece to be scraped even if the axis of rotation 111 around which the abrasive surface 172 is rotating cyclic re12 is inclined with respect to (that is, normal to) the workpiece surface. The interaction of the various components provided in the abrasive articles of the present invention preferably provides an abrasive article 120 in which one or more of the components can be compressed or deformed in such a way that the contact between the abrasive surface 172 and the surface of the workpiece. work is facilitated even if the axis of rotation is somehow tilted.

With respect to the abrasive article 120, a significant portion of such deformation can preferably occur in the compressible element 150. In some embodiments, however, additional deformation can also occur in one or more other components of the abrasive article 120. For example, base plate 140 may exhibit some flexibility in response to forces applied during the use of abrasive article 120 (despite the fact that, in some embodiments, base plate 140 may preferably be rigid, that is, base plate 140 may preferably exhibit no significant deformation in relation to the forces encountered in routine use).

The support layer 160 can also exhibit / alternatively exhibit compressibility in response to forces applied to the abrasive surface 172. As discussed below, the support layer 160 can, for example, be constructed from a compressible foam material. Although compressibility may be optional, support layer 160 is preferably resiliently flexible, so that it can be flexed and elastically deformed in response to the forces encountered when using the abrasive article.

The support layer 160 provides some support to the abrasive element 170 outside the area occupied by the compressible element 150, but preferably allows more deflection of the abrasive surface 172 than the compressible layer 150. In other words, it is preferable that the support offered to the abrasive element 170 by the underlying components to which it is attached is lower in the perimeter of the abrasive element 170 than in the center of the abrasive element 170.

In the embodiment shown, the main surface of the compressible element 150 which faces the support surface of the base plate 140 is preferably as wide as or greater than the support surface of the base plate 140. Similarly, the main surface 152 of compressible element 150 which faces away from base plate 140 is also preferably as wide as or larger than the support surface of base plate 140. By providing a compressible element 150 that is at least as wide as the support surface of the base plate 140, adverse effects of the concentration of forces on the perimeter of the base plate 140 (eg, excessive refinement, scratches, etc.) can be reduced or eliminated due to deformation of the compressible element 150.

Similarly, adding a support layer 160 that is also compressible can serve to further reduce or eliminate adverse effects that may otherwise occur at the perimeter of the compressible element 150. It should be understood, however, that the compressibility of the support layer 160 can be optional in these embodiments in which the compressible element 150 has characteristics that eliminate the need for additional compressibility in the support layer 160. In some embodiments of the invention, the support layer 160 itself may be optional where, for example, the abrasive element 170 is capable of providing sufficient support outside the area occupied by the support layer 160.

Due to the fact that the support layer 160 is provided to provide additional support to the abrasive element 170 outside the main surfaces of the compressible element 150, it is typically preferred that the main surfaces of the support layer 160 (i.e., the surfaces facing the opposite the compressible element 150) are larger than the main surface 152 of the compressible element 150. It may be preferred that the main surface 152 of the compressible element 150 occupies less than 75% (or even less than 50%) of the main surface of the support layer 160, which faces the compressible element 150 (or the main surface of the abrasive element 170 facing the compressible element 150, if no support layer 160 is present).

It may be additionally preferred that the main surfaces of the support layer 160 are as wide as the main surface of the abrasive element 170 attached to the support layer 160 (i.e., the main surfaces facing the support layer 160 and the abrasive element 170 can preferably be coextensive with each other). Alternatively, the main surface of the support layer 160 can occupy at least 90% of the main surface of the abrasive element 170 which faces the support layer.

Although the base plate 140, the compressible element 150, the support layer 160 and the abrasive element 170 are separate and distinct articles in the abrasive article 120, in some embodiments one or more of these components may alternatively be combined into unitary articles. For example, it may be possible to construct a single unitary article that provides compressible support in the central portion of the abrasive surface 172 and reduced support when it moves away from the central portion of the abrasive surface 172, such that, for example, the element compressible 150 and support layer 160 can be replaced with a single unitary article. In another example, it may be possible to combine the functions of the support layer 160 and the abrasive element 170 in a unitary article.

FIGURES 5 to 7 show alternative modalities in which one or more of the components are combined into unitary articles. FIGURE 5 is a side view of a unitary compressible support article 280 in which the compressible element and the support layer are combined. The compressible unitary support article 280 may preferably include a portion of the compressible element 250 and an integrated portion of the support layer 260. It may be preferred that the portion of the support layer 260 forms an annular ring 262 that surrounds the compressible element 250. At least the annular ring 262 of the support layer 260 may preferably be thinner than the portion of the compressible element 250, so that the annular ring 262 of the support layer portion provides less support outside the compressible element portion 250.

An abrasive element (not shown) can preferably be attached to the surface 282 of the compressible support article 280 (despite the fact that, in some cases, an abrasive layer can be formed directly on the surface 282, as discussed on here). The compressible support article 280 can be formed as a single, homogeneous mass of material (for example, a single type of foam, etc.) or it can include different materials that are combined into a unitary article (for example, insert-molded , etc.).

FIGURE 6 shows another embodiment of a unitary compressible support article 380, in which the transition between the portion of the support element 350 and the portion of the support layer 360 is more gradual than that shown in connection with the compressible support article 280 of FIGURE 5.

FIGURES 7A and 7B show yet another variation in which a base plate 440 is located within the compressible element 450. In FIGURE 7A, base plate 440 is shown separately, while FIGURE 7B shows base plate 440 embedded in the compressible element 450. The compressible element 450 and the embedded base plate 440 can be produced by any suitable process, for example, insert molding, etc. In an embodiment such as that shown in FIGURES 7A and 7B, only the portion of the compressible element 450 located on the side of the support surface 442 of the base plate 440 will act to support an abrasive surface. In this way, despite the fact that the portion of the compressible element 450 is fixed to the rear of the base plate 440, the working portion of the compressible element 450 remains fixed to the support surface 442 of the base plate 440 and preferably operates , as described in the present invention.

In addition, despite the fact that the base plate 440 is shown to be embedded in a compressible element 450, it should be understood that the base plate can be alternatively embedded in a single compressible support article, with examples of it being shown and described in connection with FIGURES 5 and 6 of the present invention.

In addition to providing abrasive methods that involve rotational reciprocating together with abrasive articles, tools and kits to practice the methods, the present invention also provides methods for correcting defects in a finished workpiece surface, where the finished workpiece surface has a colorless coat finish, varnish, etc., where defects such as lumps, etc. are found.

As discussed in this document, it may be preferable for the defects to be removed from the surface by abrasion (sanding) the defect and the area immediately surrounding the defect, with limited disturbance to any orange peel (or other) texture found on the surface of the defect. work piece.

The sanding operation carried out as part of the repair methods of the invention preferably involves sanding one or more defects in the surface of the workpiece, rotatingly reciprocating an abrasive surface of an abrasive article around an axis of rotation, using the shank of a powered tool, as described in the present invention. The workpiece surface is scraped by the abrasive particles attached to the abrasive surface of the abrasive article, while the abrasive surface of the abrasive article is rotationally reciprocated around the axis of rotation, as described in the present invention.

After the sanding of a defect is complete, the repair may also involve a polishing operation in which an area of ​​the workpiece surface that contains and surrounds the defect is worked to remove and / or reduce the scratches formed during sanding operation. As shown in FIGURE 8, the polishing operation can preferably be carried out by contacting the workpiece surface 90 with the work surface 92 of a pad 94, while the pad 94 rotates about an axis of rotation 96 extending along the surface of the workpiece 90 and the work surface 92 of the sandpaper 94. Pad 94 is rotated about at least one axis 96 in only one direction (in contrast to the rotational reciprocating movement used in connection with the abrasive surface).

It may be preferable for the pad 94 to be attached to a double-acting rotary tool such that the pad 94 moves in a movement that is commonly referred to as a random orbital pattern. During the operation of the double-acting rotary tool, the pad moves along a circular path arranged concentrically at, or in an orbit with respect to a first axis around which pad 94 is rotating, while pad 94 is also free to rotate around a second axis that is typically parallel to, but offset from, the first axis. Examples of some potentially suitable double-acting rotary tools are described, for example, in US Patent Nos. 2,794,303 and 4,854,085. Some potentially suitable double-acting rotary tools are described in the examples described in connection with this invention.

The swivel pad 94 may or may not be moved along the surface of workpiece 90 (in addition to rotation about axis 96), as desired. The swivel pad 94 can preferably be forced against the workpiece surface 90 such that the work surface 92 of the pad 94 conforms to the shape of the workpiece surface 90.

Polishing also preferably includes the use of an abrasive fluid paste 98 located between the work surface 92 of the pad 94 and the surface of the work piece 90, while the work surface of the pad rotates against the work piece surface . The abrasive slurry 98 can be applied to the work surface of the pad, to the workpiece surface, or to both the work surface of the pad and the workpiece surface. The abrasive slurry preferably contains abrasive particles in a liquid or paste-like vehicle. The abrasive particles in the abrasive slurry are preferably finer than the abrasive particles used on the abrasive surface of the abrasive element used to perform the sanding operation. Such abrasive slurries are commonly used in surface finishes and can be described as wiping compounds, polishing compounds, polishing compounds, etc.

In a polishing operation of the present invention, a variety of materials can potentially be used as work surfaces for the pads. Some materials potentially suitable for forming the work surfaces of the cushions may include natural fibers, synthetic fibers, combinations thereof, and foams (see, for example, US Patents No. 3,418,675, 4,962,562, 5,396,737 and 5,846,123). The pads may have work surfaces that are flat or that are convoluted (including prominent portions 191 and recessed portions 193 on a pad 190, as shown, for example, in FIGURE 9). Examples of some potentially suitable convoluted pads with prominent and recessed portions are described, for example, in U.S. Patent No. 5,396,737 and others.

The pads used for polishing in the methods of the present invention preferably also include resiliently compressible materials to assist in the conformity between the work surface and the workpiece surface. The work surface itself can be constructed from a resiliently compressible material and / or the materials that support the work surface can be resiliently compressible. Examples of some pads potentially suitable for use in the polishing methods of the invention can be identified in the examples provided at the end of this document (before the claims).

Due to the fact that the sanding operation can preferably be performed using smaller abrasive articles, as described in the present invention, polishing operations can also be performed using pads with work surfaces that are also relatively small. For example, it may be preferable that the work surfaces of the cushions have an area of ​​about 2,000 mm² or less, in some cases, about 1,000 mm² or less, and in some cases, about 500 mm² or less.

While the rotational reciprocating movement of an abrasive article (even a minor abrasive article as discussed in this document) can provide enough abrasive energy to remove defects, the amount of abrasive energy is preferably small enough that the scratches formed are shallower and / or less material is removed from the workpiece surface (compared to a process using a rotary sander). Shallow scratches may preferably require less extensive refinishing compared to more conventional sanding / refinishing methods.

In the surface repair methods of the present invention, sanding any area surrounding and containing one of the defects can preferably be followed by one or more subsequent polishing operations on the same area. If two or more polishing operations are carried out after sanding, it may be preferable that any abrasive particles used in the subsequent polishing operations are successively finer. In other words, it may be preferable that the abrasive particles in any subsequent polishing operation are finer than the abrasive particles in the abrasive slurry used in the previous polishing operation.

In another variation, the work surfaces of the pads used in methods that include two or more polishing operations can be the same, that is, the work surfaces can be of the same shape and can be made from the same materials. Alternatively, the work surfaces of the pads used in two or more polishing operations can be different in one or more aspects, that is, the shape and / or materials used for the work surfaces can be different between the two polishing operations.

The following discussions provide additional descriptions of the various components that may be present in the abrasive articles used in connection with the present invention.

Base plates:

The base plate used in connection with the present invention preferably provides a platform on which the rest of the abrasive article is supported. It may be preferable that the base plate also includes a structure that can join the shank of a motorized tool, as discussed in this document, despite the fact that the coupling structure can be supplied separately from the base plate.

The base plate preferably provides a rigid platform that does not deform or significantly deflect in response to the forces exerted on the base plate during normal use. It may be preferable for the base plate to provide a flat support surface to which the compressible element can be attached. The flat support surface may preferably be normal to the axis of rotation around which the base plate (and thus the abrasive article) reciprocates during use.

Examples of some potentially suitable materials from which the base plate can be manufactured can include, for example, wood, metals, plastics, composites, etc.

Compressible elements:

The optional compressible elements used in connection with the present invention preferably support a central portion of the abrasive surface of the abrasive articles used in connection with the present invention. It is theorized that the resilient compressibility of the compressible element limits the concentration of forces applied by the abrasive surface at the edges of the base plate. It may also be preferred that, in addition to resilient compressibility, the compressible element also provides some torsional flexing to the system, such that the compressible element can be twisted in response to changes in the rotational direction of the tool's motorized shank.

The compressible element is preferably attached to a support surface of the base plate by any suitable technique or combination of techniques (for example, hot melt adhesives, pressure sensitive adhesives, curable adhesives, glues, thermo-lamination, chemical welding, molding by injection, etc.). Useful adhesives may include, for example, pressure-sensitive acrylic adhesives, pressure-sensitive rubber-based adhesives, water-resistant lattices, solvent-based adhesives, and two-part resins (for example, epoxies, polyesters, or polyurethanes) . Examples of potentially suitable pressure sensitive adhesives can include those derived from acrylate polymers (eg, polybutyl acrylate or polyacrylate esters), acrylate copolymers (eg, isooctyl acrylate / acrylic acid), vinyl ethers (eg , polyvinyl n-butyl ether), alkyd adhesives, rubber adhesives (for example, natural rubbers, synthetic rubbers and chlorinated rubbers), and mixtures thereof. An example of a pressure sensitive adhesive coating is described in US Patent No. 5,520,957 (Bange et al.). These adhesives can also be used to fix various other components (for example, the backing layer, the abrasive element, etc.) to the abrasive article.

The material used to form the compressible element can include gas (for example, air), liquid (for example, water, oil), foam (for example, as described in the present invention), a semi-solid gel or paste, combinations of themselves, etc. In some cases, the compressible element may be in the form of a torsion spring. The compressible elements can be manufactured as unitary articles (for example, a single uniform layer of foam) or they can include one or more materials (for example, a gel enclosed in an elastomeric bladder). However, it may be preferable that the main surface of the compressible element that faces the abrasive element in the construction is flat (that is, that it is not shaped like a dome, curve, cone, truncated cone, ridges, polyhedron, truncated polyhedron , or other nonplanar shapes (for example, tent-shaped surfaces).

In some embodiments, the compressible material may include an elastomer. For example, the compressible material may comprise, or even consist essentially of, at least one elastomeric gel or foamed elastomeric gel, which typically comprises a highly plasticized elastomer. Examples of potentially useful elastomeric gels may include polyurethane elastomer gels, for example, as described in US patent No. 6,908,979 (Arendoski), SEEPS elastomer gels, for example, as described in US patents No. 5,994,450 and 6,797,765 (both assigned to Pearce), styrene-butadiene-styrene / oily gels, and silicone elastomer gels, for example, as described in US Patent No. 6,013,711 (Lewis et al.).

For solid and gei materials, the elastic modulus (measured at 1 Hz and 25 ° C) of the compressible material can preferably be between about 1500 and about 4.9 x 10⁵ Pascals (Pa), for example, between about 1,750 and about 1 x 10⁵ Pa, despite the fact that this is not a requirement. Examples of such compressible materials can include styrene-butadiene-styrene / oily gels (for example, those that have elastic modules of 1,992 Pa at 1 Hz and 25 ° C), urethane foam (for example, those that have an elastic module of 3, 02 x 10⁵ Pa at 1 Hz and 25 ° C or 4.31 x 10⁵ Pa at 1 Hz and 25 ° C), and elastomeric urethane rubber (for example, those that have a 4.89 x 10 module⁵ Pa at 1 Hz and 25 ° C).

Typically, the thickness of the compressible element will be selected based on factors such as, for example, the intended use and the overall size of the abrasive article. In addition, it may be preferable that the thickness of the compressible element is substantially uniform across its main surfaces. In some embodiments, the thickness of the compressible element can be, for example, about 0.5 millimeters (mm) or more, in some cases,. 1 mm or more, or even 1.5 mm or more. At the upper end, the thickness of the compressible elements can preferably be about 5 mm or less, preferably about 3 mm or less, or even about 2 mm or less. Compressible elements with thickness outside these ranges can also be used.

Support layer:

As discussed in this document, the optional support layer is preferably a flexible resilient layer, which provides support to the abrasive element during use. The support layer can preferably be located between the compressible element and the abrasive element, in the abrasive articles of the present invention. The backing layer can be attached to the compressible element by any suitable technique or combination of techniques (for example, hot melt adhesives, pressure sensitive adhesives, curable adhesives, glues, thermo-lamination, chemical welding, coextrusion, injection molding, etc.).

In addition to being flexible and resilient, it may be preferable that the support layer is also compressible, in such a way that it can be compressed in response to the forces exerted on the abrasive surface supported by the support layer, during use.

In some embodiments, the backing layer may preferably be constructed from a resilient compressible material, for example, foams, etc. Some potentially useful compressible foams may include, for example, polyvinyl chloride foams, chloroprene rubber foams, ethylene / prolylene rubber foams, butyl rubber foams, polybutadiene foams, polyisoprene foams, EPDM polymer foams , polyurethane foams, ethylene - vinyl acetate foams, neoprene foams, and styrene / butadiene copolymer foams.

The thickness of the support layer can be, for example, about 0.01 mm or more, or even 0.1 mm or more. At the upper end, the support layer can be about 2 mm or less in thickness, or even 1 mm or less. Support layers with thickness outside these ranges can also be used.

Abrasive elements:

The abrasive elements used in the abrasive articles of the present invention provide the abrasive surface used to scrape the workpieces. The abrasive elements may preferably include an abrasive layer that is optionally attached to a flexible backing layer (i.e., a coated abrasive article). The optional flexible back layer of the abrasive element can be elastic or inelastic.

In some embodiments, it may be possible to use the backing layer as a flexible backing layer for the abrasive element. In such embodiments, the abrasive layer may preferably be attached to the support layer as part of the process for manufacturing the abrasive element. In other modalities, the. abrasive element is manufactured separately and then attached to the optional support layer.

The abrasive element can be attached to the backing layer (or compressible element if no backing layer is present) by any suitable technique or combination of techniques (for example, hot melt adhesives, pressure sensitive adhesives, curable adhesives, glues, thermal laminating, welding chemistry, coextrusion, etc.).

In some embodiments, the abrasive layers may include production and size layers and abrasive particles, as shown, for example, in FIGURE 10A, where the abrasive layer 570 includes a production layer 574, abrasive particles 576, a size 578 layer , and an optional 580 magnification layer. Production, size and optional expansion layers, coated and flexible abrasive articles, and potentially useful methods for producing them may include, for example, those described in US patents No. 4,588,419 (Caul et al.), 4,734 .104 (Broberg), 4,737,163 (Larkey), 4,751,138 (Tumey et al.), 5,078,753 (Broberg et al.), 5,203,884 (Buchanan et al.), 5,152,917 (Pieper et al. .), 5,378,251 (Culler et al.), 5,366,523 (Rowenhorst et al.), 5,417,726 (Stout et al.), 5,436,063 (Follett et al.), 5,490,878 (Peterson et al.), 5,496,386 (Broberg et al.), 5,609,706 (Benedict et al.), 5,520,711 (Helmin), 5,954,844 (Law et al.), 5,961,674 (Gagliardi etal.), 4,751,138 (Tumey et al.), 5,766,277 (DeVoe et al.), 6,059,850 (Lise et al.), 6,077,601 ( DeVoe et al.), 6,228,133 (Thurber et al.), And 5,975,988 (Christianson), those marketed by 3M Company under the trade names “260L IMPERIAL FINISHING FILM”, etc.

In other embodiments, the abrasive layer may include abrasive particles in a binder, typically distributed substantially uniformly throughout the entire binder, as shown, for example, in FIGURE 10B, where abrasive layer 670 includes binder 674 and particles abrasives 676. Details related to materials and manufacturing methods such as potentially suitable abrasive layers can be found, for example, in US patents No. 4,927,431 (Buchanan et al.), 5,014,468 (Ravipati et al.), 5,378,251 (Culler et al.), 5,942,015 (Culler et al.), 6,261,682 (Law), and 6,277,160 (Stubbs et al.), and in US patent applications published under numbers 2003/0207659 A1 (Annen et al.) and 2005/0020190 A1 (Schutz et al.), etc.

As discussed in this document, in the modalities where the abrasive element itself does not include a separate backing layer, it may be possible to apply a fluid paste of abrasive particles in a binder precursor directly to the support layer material described here, and then cure to the least partially the slurry to form an abrasive element in the backing layer. Examples of potentially useful coated and flexible abrasive articles of this embodiment may include those described in US Patent No. 6,929,539 (Schutz et al.).

In some embodiments, the abrasive layer may be in the form of a structured abrasive layer, for example, as shown in FIGURE 10C, where the structured abrasive layer 770 includes abrasive composites 775 (where the term "abrasive composite" refers to a structure that includes abrasive particles and a binder). Abrasive composites 775 include abrasive particles 776 dispersed throughout the binder 774. In such embodiments where the abrasive element itself does not include a separate back layer, it may be possible to form the structured abrasive layer 770 directly on the support layer material, as described in the present invention.

Structured abrasive layers that can be used in connection with the present invention can include abrasive composites in the form of a plurality of non-randomly shaped structures. Abrasive composites 775 can preferably be arranged according to a predetermined pattern (for example, as a matrix).

In some embodiments, at least a portion of the 775 abrasive composites may preferably be "precisely molded" abrasive composites. This means that the shape of the abrasive composites is defined by relatively smooth sides that are delimited and joined by well-defined edges whose lengths are distinct with distinct extreme points defined by the intersections of the various sides. The terms "delimited" and "contour" refer to the exposed surfaces and edges of each composite that delimit and define the actual three-dimensional shape of each abrasive composite. These contours are readily visible and discernible when the cross section of an abrasive article is visualized through a scanning electron microscope. These contours separate and distinguish an abrasive composite that is precisely molded from any other, even when the composites fit together along a common edge at their bases. By comparison, in an abrasive composite that does not have a precise shape, the limits and edges are not well defined (for example, where the abrasive composite bends before its curing is completed). Typically, precisely shaped abrasive composites are arranged on the back layer, according to a predetermined pattern or formation, although it is not a requirement.

Molded abrasive composites can be arranged in such a way that a part of their work surfaces are recessed from the outer surfaces of the abrasive layer.

Suitable optional flexible back layers that can be used in connection with abrasive elements may include back layers used in abrasive techniques such as flexible polymeric films (including primed polymeric films and elastomeric polymeric films), elastomeric cloth, polymeric foam (for example , polyvinyl chloride foam, polyurethane foam, etc.), and combinations thereof. Examples of suitable flexible polymeric films include polyester films, polypropylene films, polyethylene films, ionomer films (for example, those available under the trade name “SURLYN”, available from EI du Pont de Nemours &amp; Co., Wilmington , Delaware, USA), vinyl films, polycarbonate films and their laminates.

Structured abrasive composites can be prepared by forming a slurry of abrasive particles and a solidifiable or polymerizable precursor of the binder resin mentioned above (ie, a binder precursor), placing the slurry in contact with the supporting element (or directly with the support layer), and solidifying and / or polymerizing the binder precursor (for example, through exposure to electromagnetic radiation or thermal energy), in such a way that the resulting structured abrasive article has a plurality of molded abrasive composites attached to the support element.

Examples of some potentially suitable energy sources may include, for example, thermal energy and radiant energy (including electron beam, ultraviolet light, and visible light).

In some embodiments, the watery paste can directly coat a production tool having precisely shaped cavities in it made to make contact with the reinforcement or to coat the reinforcement and brought into contact with the production tool. In such an embodiment, the slurry is then typically solidified or cured, while it is present in the cavities of the production tool. US patent No. 6,929,539 (Schutz et al.) Presents some potentially suitable processes for carrying out this process.

Precisely molded abrasive composites can have any three-dimensional shape that results in at least one prominent feature or recess in the exposed surface of the abrasive layer. Useful formats can include, for example, cubic, prismatic, pyramidal shapes (e.g. square pyramids or hexagonal pyramids), truncated, conical, frusto-conical pyramids, doghouse-shaped, crest-shaped, etc. Combinations of abrasive composites with different shapes and / or sizes can also be used on the same abrasive element. The abrasive layer of the structured abrasive element can be continuous or discontinuous.

For fine finishing applications, the density of abrasive composites molded on the abrasive surface can typically be in the range of at least about 1,000, about 10,000, or even at least about 20,000 abrasive composites per 6.45 cm²(square inch) (for example, at least about 150, about 1,500, or even about 7,800 abrasive composites per square centimeter) up to and including about 7,800, about 11,000, or even as much as about 15,000 abrasive composites per square centimeter (up to and including about 50,000, about 70,000, or even as much as about 100,000 abrasive composites per square inch), despite the fact that higher or lower density of abrasive composites can also be used.

Additional details related to structured abrasive layers that have precisely molded abrasive composites, and methods for their manufacture can be found, for example, in US Patent No. 5,152,917 (Pieper et al.), 5,304,223 (Pieper et al. ), 5,435,816 (Spurgeon et al.), 5,672,097 (Hoopman), 5,681,217 (Hoopman et al.), 5,454,844 (Hibbard et al.), 5,549,962 (Holmes et al.), 5,700 .302 (Stoetzel et al.), 5,851,247 (Stoetzel et al.), 5,910,471 (Christianson et al.), 5,913,716 (Mucci et al.), 5,958,794 (Bruxvoort et al.), 6,139,594 (Kincaid et al.), 6,923,840 (Schutz et al.), And in the US patent application published under number 2003/0022604 (Annen et al.).

Some structured abrasive elements that have precisely shaped abrasive composites that can be useful for the practice of the present invention are commercially available as films and / or disks, for example, marketed under the trade name “3M TRIZACT FINESSE-IT” by 3M Company, from Saint Paul, Minnesota, USA. Examples include ο “3M FINESSE-IT TRIZACT FILM, 466LA” available in grades A7, A5 and A3. Structured abrasive elements that have larger abrasive composites can also be usable in the practice of the present invention, for example, those marketed under the trade name “TRIZACT CF”, available from 3M Company.

The structured abrasive elements can also be prepared by coating an aqueous paste comprising a polymerizable agglutinating precursor, abrasive particles and an optional silane coupling agent, through a screen that comes into contact with a back layer. In this embodiment, the slurry is then typically polymerized (for example, by exposure to a source of energy) while it is present in the screen openings, thus forming a plurality of molded abrasive composites, generally corresponding in shape to the openings of the screen. Further details related to this type of structured abrasive coated with canvas can be found, for example, in US patents No. 4,927,431 (Buchanan et al.), 5,378,251 (Culler et al.), 5,942,015 (Culler et al.), 6,261,682 (Law), and 6,277,160 (Stubbs et al.).

In some embodiments, a slurry comprising a precursor of polymerizable binder, abrasive particles, and an optional silane bonding agent can be deposited on a back layer in a standardized manner (for example, by projection or print by engraving), partially polymerized to cause at least the surface of the coated slurry to become plastic but not to flow, a pattern printed on the partially polymerized slurry formulation, and subsequently be further polymerized (for example, by exposure to an energy source) to form a plurality of molded abrasive composites affixed to the back layer. Embossed and embossed abrasive elements prepared by this method and related methods are described, for example, in US patent application published under number 2001/0041511 (Lack et al.). Commercially available examples of such structured and embossed abrasive elements are believed to include abrasive bands and discs available from Norton-St. Gobain Abrasives Company, Worcester, Massachusetts, USA, under the trade name “NORAX”, such as “NORAX U264 - X80”, “NORAX U266 - X30”, “NORAX U264 X80”, “NORAX U264 - X45” , "NORAX U254 - X45, X30", "NORAX U264 - X16", "NORAX U336 - X5" and "NORAX U254 - AF06".

Structured abrasive layers can also be prepared by coating a fluid paste comprising a precursor of polymerizable binder, abrasive particles, and an optional silane bonding agent through a screen that is in contact with the elastic member, which you can optionally have. a fixation or surface treatment layer on it. In this embodiment, the slurry is then typically polymerized (for example, by exposure to a source of energy such as heat or electromagnetic radiation) while it is present in the screen openings, thus forming a plurality of molded abrasive composites, generally corresponding in format to the screen openings. Further details related to this type of structured coated abrasive can be found, for example, in US Patent No. 4,927,431 (Buchanan et al.), 5,378,251 (Culler et al.), 5,942,015 (Culler et al.), 6,261,682 (Law), and 6,277,160 (Stubbs et al.), and in the US patent application published under number 2001/0041511 (Lack et al.).

The polymerizable binder precursors that can be cured to form the aforementioned binders are well known and include, for example, thermally curable resins and radiation curable resins, which can be cured, for example, thermally and / or upon exposure to radiation energy. Exemplifying polymerizable binder precursors include phenolic resins, aminoplastic resins, urea-formaldehyde resins, melamine formaldehyde resins, urethane resins, polyacrylates (eg, an aminoplastic resin having polymeric unsaturated groups free of pendant radicals, urethane acrylates, isocyanurate acrylates, isocyanurate , (poly) acrylate monomers and acrylic resins), alkyd resins, epoxy resins (including bis-maleimide and fluorene-modified epoxy resins), isocyanurate resins, alkyl resins, furan resins, cyanate esters, polyimides and the mixture thereof. Polymerizable binder precursors may contain one or more reactive diluents (for example, low viscosity monoacrylates) and / or adhesion-promoting monomers (for example, acrylic acid or methacrylic acid).

In the case of the use of ultraviolet radiation or invisible radiation, the polymerizable agglutinating precursor also typically comprises a photoinitiator. Examples of photoinitiators that generate a free radical source include, but are not limited to, organic peroxides, azo compounds, quinones, benzophenones, nitrous compounds, acyl halides, hydrazones, mercapto compounds, pyrilium compounds, triacrylimidazoles, bisimidazoles, phosphene oxides , chloroalkyltriazines, benzoyl ethers, benzyl ketal, thioxanthones, acetophenone derivatives, and combinations thereof.

Cationic photoinitiators generate an acid source to initiate the polymerization of an epoxy resin. Cationic photoinitiators can include a salt having an anion cation and a halogen containing a complex metal or metalloid anion. Other cationic photoinitiators include a salt having a complex organometallic cation and a halogen containing a complex metal or metalloid anion. They are also disclosed in US Patent Number 4,751,138. Another example of a cationic photoinitiator is an organo-metallic salt and an onion salt, described in US Patent No. 4,985,340, and in European Patent Publications No. EP 306,161 and EP 306,162. Still other cationic photoinitiators include an anionic salt from an organo-metallic complex, in which the metal is selected from elements of the periodic groups IVB, VB, VIB, VIIB and VIIIB.

The polymerizable binder precursor can also include resins that are curable by energy sources in addition to radiant energy, such as condensation-curable resins. Examples of these condensation-curable resins include phenolic resins, melamine formaldehyde resins and urea-formaldehyde resins.

The binder precursor and binder may include one or more optional additives selected from the group consisting of crushing aids, fillers, wetting agents, blowing chemical blowing agents, surfactants, pigments, coupling agents, dyes, initiators, energy receptors and the mixture of these. Optional additives can also be selected from the group consisting of potassium fluoroborate, lithium stearate, glass bubbles, inflatable bubbles, glass beads, cryolites, polyurethane particles, polysiloxane gum, polymeric particles, solid waxes, waxes and their mixture.

The abrasive particles usable in the present invention, in general, can be divided into two classes: natural abrasives and manufactured abrasives. Examples of usable natural abrasives include: diamond, corundum, emery, garnet (reddish), buhrstone, horny flint, quartz, garnet, emery, sandstone, chalcedony, flint, quartzite, silica, feldspar, crushed natural aluminum oxide, pumice stone and talc. Examples of manufactured abrasives include: boron carbide, cubic boron nitride, molten alumina, aluminum oxide ceramics, heat-treated aluminum oxide (both dark brown and gray), molten zirconia alumina, glass, glass-ceramics, silicon carbide, iron oxides, carbide tantalum, chromia, cerium oxide, tin oxide, titanium carbide, titanium diboride, synthetic diamond, manganese dioxide, zirconium oxide, ceramics based on sol-gel alumina, silicon nitride, and agglomerates thereof. Examples of abrasive sol-gel particles can be found in US Patent Numbers 4,314,827 (Leitheiser et al.), 4,623, .64 (Cottringer et al.), 4,744,802 (Schwabel), 4,770,671 (Monroe et al. .) and 4,881,951 (Wood et al.).

The size of an abrasive particle is typically specified, having the longest dimension of the abrasive particle. In most cases there will be a wide distribution on the size of particles. The particle size distribution can be rigidly controlled such that the resulting abrasive article provides a surface finish consistent with the workpiece being ground, however, wide and / or polymodal particle size distributions can also be used

The abrasive particle can also have a shape associated with it. Examples of these shapes include rods, triangles, pyramids, cones, solid spheres, hollow spheres and the like. Alternatively, the abrasive particle can be shaped at random.

Abrasive particles can be coated with materials that provide particles with the desired characteristics. For example, materials applied to the surface of an abrasive particle have been shown to improve the adhesion between the abrasive particle and the polymer. In addition, a material applied to the surface of an abrasive particle can improve the adhesion of the abrasive particles to the flexible particle-curable binder material. Alternatively, surface coatings can alter and improve the cutting characteristics of the resulting abrasive particle. Such surface coatings are disclosed, for example, in US Patent Numbers 5,011,508 (Wald et al.), 3,041,156 (Rowse et al.), 5,009,675 (Kunz et al.), 4,997,461 ( Markhoff-Matheny et al.), 5,213,591 (Celikaya et al.), 5,085,671 (Martin et al.) And 5,042,991 (Kunz et al.).

In some embodiments, for example, those that include molded abrasive composites, the abrasive particles used in the abrasive elements of the present invention may preferably have a particle size of about 0.1 micrometer (pm) or more. At the upper end of the strip, the abrasive particles can have a particle size of about 450 pm or less, or even 100 pm or less. In some embodiments, the abrasive particles may have a size within a range of JIS 800 grade (14 pm at 50% midpoint) or more, or even a JIS 1000 grade (12 pm at 50% midpoint). At the opposite end of the strip, the abrasive particles have a JIS 6000 grade size (2 pm at 50% midpoint) or less, in some cases, a JIS 4000 grade (3 pm at 50% midpoint) or less, or even a JIS 2000 grade (from 5 to 8 pm at 50% of the midpoint) or less.

Typically, the abrasive particles used in the present invention have a Moh hardness scale of at least 8, more typically over 9, however, abrasive particles that have a Moh hardness scale of less than 8 can be used.

Aspects of this invention can be further illustrated by the following non-limiting examples, but the specific materials and quantities recited in these examples, as well as other conditions and details, are not to be construed as limiting this invention.

Sanding examples

The following descriptions demonstrate the exemplary use of the abrasive articles, tools and methods of the present invention, and abrasive articles, tools and comparative methods.

ROTARY RECIPROCATING TOOL: The reciprocating rotary power tool used in examples 1 to 4 was manufactured as follows. The plastic brush head housing of a battery powered toothbrush, model “Oral B AdvancePower 450TX” (Braun GmbH, Kronberg, Germany), has been removed. The exposed connector of the brush head was cut to a length of approximately 2.54 cm (1 inch), and the end was sanded to form a smooth distal face perpendicular to the length of the toothbrush drive shaft. A 0.64 cm (0.25 inch) diameter and 0.84 mm (0.033 inch) thick hard plastic disk was then joined to the distal face using a 2 part epoxy resin and a hardener (commercially available under the trade name “Quick Weld Compound”, from Dynatex, from Elizabethtown, Kentucky, USA), to form a set with a removable base plate along with a 0.64 cm (0.25 inch) support surface ) in diameter, oriented perpendicularly to the rotating reciprocating rod of the tool. The tool was equipped with two AA size 3-volt lithium batteries, “part No. U-3191”, obtained from the Apex Battery, of Anaheim Hills, California, USA.

CONVENTIONAL ROTARY TOOL: The conventional sander used in the examples was a pneumatically powered double action sander, model number

57500 (from Dynabrade, Inc., Clarence, New York, USA) in combination with a 3.2 cm (1.25 inch) support surface (commercially available under the trademark FINESSE-IT ROLOC sanding block, number of part 02345, available from 3M, St. Paul, Minnesota, USA) to support abrasive discs attached to a conventional sander, as discussed in connection with the comparative examples.

STRUCTURED ABRASIVE ELEMENTS: Structured abrasive elements used in connection with the sanding examples and tests described here have been manufactured using the following materials (identified below by the abbreviations that appear at the beginning of each of the following descriptions):

PA1: a trimethylol propane triacrylate monomer, with a molecular weight of 296 and a functionality of 3, available under the trade name “SR 351”, available from Sartomer Company, Exton, Pennsylvania, USA,

PA2: an aromatic 2-phenoxy ethyl acrylate monomer, with a molecular weight of 192 and a functionality of 1, available under the trade name “SR 339”, available from the Sartomer Company,

PA3: a polymeric dispersant available under the trade name “Solplus D520”, available from Noveon, Inc., Cleveland, Ohio, USA,

PA4: a gamma-methacryloxypropyl-trimethoxy-silane resin modifier available under the trade name “Silquest A174”, available from Witco Corporation, Greenwich, Connecticut, USA,

PA5: an ethyl 2, 4, 6-trimethylbenzoylphenylphosphinate photoinitiator available under the trade name “Lucirin TPO-L”, available from BASF Corp., Charlotte, North Carolina, USA, and

PA6: green abrasive silicon carbide particles that have a JIS 1500 grade size and an average particle size of 8.0 micrometers (pm) at 50% of the midpoint, available under the trade name “Fujimi GC 1500”, together to Fujimi Abrasives Company, Elmhurst, IL, USA.

An abrasive slurry was produced at 20 degrees centigrade (° C) by mixing the mentioned components in parts by weight, until homogeneous: 12.9 parts of PA1, 19.5 parts of PA2, 3.1 parts of PA3, 1.9 parts of PA4, 1.1 parts of PA5 and 61.5 parts of PA6. The slurry was applied by knife coating to a polypropylene abrasive tool, produced according to the methods described in US patent No. 6,846,232 (Braunschweig et al.). The dimensions of the abrasive tool used in Examples 1 to 4 below are described in Example 2 of US Patent No. 6,846,232.

The coated production tool was applied to the main face of a 76 micrometer (pm) (0.003 inch) polyester film, available under the trade name SCOTCHPAK polyester film, available from 3M Company, St. Paul, Minnesota, USA . The production tool was then irradiated with an ultraviolet (UV) lamp with a “D” type bulb, available from Fusion Systems Inc., of Gaithersburg, Maryland, USA, at 600 Watts per inch (236 Watts per centimeter ( W / cm)) by moving the mat at 9.14 meters / minute (30 feet per minute), at a line pressure of 620.5 kilopascals (kPa) (90 pounds per square inch) for a mat of 25.4 cm (10 inches) wide, and with a mandrel temperature of 60 ° C. The blanket with the structured abrasive layer formed in it was separated from the production tool and cut by matrix into abrasive elements structured in the form of a disk of 1.27 cm (0.5 inches) in diameter.

EXAMPLE 1: An abrasive article was manufactured using a transfer adhesive (commercially available under the trade name “9453LE”, available from 3M Company) that was applied to the non-abrasive face of a 1.27 structured abrasive element cm (0.5 inches) in diameter (manufactured as described above). The largest abrasive element 1.27 cm (0.5 inch) in diameter was centered on and attached to the smaller support surface 0.63 cm (0.25 inch) in diameter of the base plate assembly. The abrasive article of example 1 thus includes the following components shown in FIGURE 4: the base plate 140 and the abrasive element 170 directly attached to the base plate 140. The abrasive article was then used as described in the sanding no. 1 below.

EXAMPLE 2: An abrasive article was produced by matrix cutting a 1.27 cm (0.5 inch) diameter polyvinyl foam disk and 0.69 mm (0.027 inch) thick, commercially adhesive bandage available under the trade name NEXCARE ADHESIVE STRIP BANDAGE, available from 3M Company. The adhesive liner was removed and the adhesive face of the foam disc was attached to the main non-abrasive surface of a structured abrasive element measuring 1.27 cm (0.5 inches) in diameter (manufactured as described above). The transfer adhesive of example 1 was then applied to the non-adhesive face of the foam disc. The main surface coated with the transfer adhesive of the larger 1.27 cm (0.5 inch) diameter polyvinyl foam disc (with its structured abrasive element) was then centered on and attached to the smaller support surface. 0.63 cm (0.25 inch) diameter of the base plate assembly. The abrasive article of example 2 thus includes the following components shown in FIGURE 4: the base plate 140, a support layer 160 (a polyvinyl foam disc) and an abrasive element 170. The support layer 160 was fixed directly to the base plate 140. The abrasive article was then used as described in sanding test No. 1 below.

EXAMPLE 3: An abrasive article was produced according to the method described in example 2, except that the 1.27 cm (0.5 inch) diameter polyvinyl foam was replaced by a polyurethane foam disc of 7.9 mm (5/16 inch) with 2.29 mm (0.090 inch) thick, commercially available under the trade name “R600U-090”, available from the llbrbruck Company, Minneapolis, Minnesota,

USA. The largest structured abrasive element, 1.27 cm (0.5 inches) in diameter, was centered on the smaller 7.9 mm (5/16 inch) diameter polyurethane foam disk. The 7.9 mm (5/16 inch) diameter polyurethane foam disc was centered on the 0.63 cm (0.25 inch) diameter support surface of the base plate assembly. The abrasive article of example 3 thus includes the following components shown in FIGURE 4: the base plate 140, the compressible element 150 (a polyurethane foam disc) and the abrasive element 170. The abrasive element 170 was fixed directly to the compressible element 150. The abrasive article was then used as described in sanding test No. 1 below.

EXAMPLE 4: An abrasive article was manufactured to include all components represented in FIGURE 4, that is, the base plate 140 (as described in connection with the rotary reciprocating tool above), the compressible element 150 (the polyurethane foam disc described in connection with example 3), the support layer 160 (the polyvinyl foam disk described in connection with example 2), and the abrasive element 170 (an abrasive element structured as described above). Except for the adhesive already located on one side of the polyvinyl foam discs, the transfer adhesive identified in example 1 was used to fix the components together. The smaller diameter components (the base plate 140 and the compressible polyurethane foam element 150) were centered on each and the larger components (the polyvinyl foam support layer 160 and the structured abrasive element 170) were centered on the compressible element. The abrasive article was then used as described in sanding test No. 1 below.

COMPARATIVE EXAMPLE A: An abrasive article in the form of an abrasive disk with a diameter of 3.2 cm (1.25 inches) and a JIS 3000 grade (commercially available under the trade name “466LA A5, part number 56251”, available 3M Company) was mounted on a conventional sander described above. The abrasive article was then used as described in sanding test No. 2 below.

COMPARATIVE EXAMPLE B: An abrasive article was formed using a commercially available abrasive sheet under the trade name “401Q WETORDRY Grade 2000”, available from 3M Company, which has been folded to a format suitable for use in the manual sanding test No. 3 below.

TEST MEASUREMENTS: A test panel with a colorless coat, painted black and made of cold rolled steel, which has an orange peel texture, and which measures 45.7 cm by 61 cm (18 by 24 inches), part number “APR45077”, was obtained from ACT Laboratories, Inc., Hillsdale, Michigan, USA.

ORANGE PEEL: The level of “orange peel” finish on the test panel was measured using a surface texture analyzer, model “WaveScan DOI”, obtained from BYK-Gardner USA, Columbia, Maryland, USA . The scan values ​​recorded below represent an average of 3 scans, each 5 cm long, from different areas of the scraped test area, measured after polishing. It is theorized that deviation from the control values ​​(not sanded) of the panel, in particular W_ç and W_d, reflect changes in the orange peel due to the sanding process.

SURFACE FINISH: The surface finish (R_z - the maximum vertical distance between the highest and the lowest point of a test area) was measured after the sanding step using a profilometer, model “SURTRONIC 3+ PROFILOMETER”, obtained from Taylor Hobson, Inc. , Leicester, England. The R values_zrecorded below represent the average of 5 individual measurements of a sanded area of ​​2 centimeters by 6 centimeters.

REFINING: Refinement was a subjective rate of the level of major surface irregularities caused by excessive tipping (ie, out of angle, non-plane, etc.) during the sanding process. The refinement values ​​were recorded on a subjective scale from zero (0) to five (5), where zero (0) represents no irregularities.

SANDING TEST N ° 1: The abrasive articles from examples 1 to 4 were used on the rotary reciprocating tool to sand an area of ​​the test panel. For each different abrasive article, the tool was switched on and, with minimal lateral movement and a sanding angle of zero degrees (that is, the flat abrasive surface was kept parallel to the workpiece surface), a defect previously identified under the the shape of a lump on the test panel was sanded until removed, to establish a 7-second sanding time baseline. The abrasive article in the tool was replaced and a clean area of ​​the test panel was sanded for the same amount of time. The abrasive article was replaced and an adjacent area was then sanded for 7 seconds. This process was repeated until the matte or sanded area on the test panel was 2 cm by 6 cm, after which the area was contoured with the use of a permanent marker for subsequent identification after polishing.

Each sanded area was then polished for 6 seconds at 1,400 rpm, using the following configuration: Polisher: a Dewalt electric buffer, model number “DW849”, obtained from Dewalt Industrial Tool Corp., Hampstead, Maryland, USA , Support surface: a “Perfect-it support block # 05718”, Polishing pad: a “PERFECT-IT foam polishing block # 05725”, and Retoucher: a “Perfect-it 3000 Trizact Spot Finishing Material # 06070 ”, All available from 3M Company.

COMPARATIVE SANDING TEST N ° 2: The abrasive element of comparative example A was fixed to the support surface of the conventional sander described and the pneumatic line pressure fixed to the tool was adjusted to 620.5 kiloPascals (kPa) (90 pounds per square inch) (psi)). With minimal lateral movement and a sanding angle of zero degrees, a protrusion previously identified on the test panel was sanded until removed, thereby establishing a sanding time baseline of 3 seconds. The abrasive disc was replaced by another sample and an adjacent area was then sanded for 3 seconds. This process was repeated once more until the matte area was approximately 3 cm by 9 cm, after which time the area was made using a permanent marker. Each sanded area was then polished according to the method described in sanding test No. 1.

SANDING TEST No. 3: By applying light manual pressure, and with minimal lateral movement, the test panel was manually sanded using unidirectional strokes for 3 seconds, with the abrasive article described in comparative example B. The abrasive article was replaced and an adjacent area was sanded. This was repeated until the sanded area was approximately 2 cm by 6 cm.

Table 1 presents the results of the sanding tests discussed above: Table 1

<td>Sample Abrasive</td><td>Test of Sanding</td><td>Refinement</td><td>Wa</td><td>Wb</td><td>Wc</td><td>Wd</td><td>We</td><td>Rz (pm)</td>

<td>Dashboard CnntrnlA</td><td>AT</td><td>AT</td><td> 4,7</td><td> 16,5</td><td> 13,4</td><td> 16,7</td><td> 12,5</td><td>AT</td>

<td>Example 1</td><td> 1</td><td></td><td>AA 1 1, /</td><td> 24,7</td><td> 21,3</td><td> 28,2</td><td> 19,9</td><td> 0,81</td>

<td>Example 2</td><td> 1</td><td> 3</td><td> 3,3</td><td> 8,1</td><td> 7,1</td><td> 17,4</td><td> 12,8</td><td> 0,71</td>

<td>Example 3</td><td> 1</td><td> 2</td><td> 4,0</td><td> 9,0</td><td> 6,4</td><td> 16,1</td><td> 20,6</td><td> 0,33</td>

<td>Example 4</td><td> 1</td><td> 0</td><td> 5,4</td><td> 17,6</td><td> 10,3</td><td> 13,8</td><td> 10,3</td><td> 0,33</td>

<td>Comparative A</td><td> 2</td><td> 0</td><td> 5,7</td><td> 10,3</td><td> 2,9</td><td> 5,0</td><td> 11,9</td><td> 0,48</td>

<td>Comparative B</td><td> 3</td><td> 3</td><td> 4,4</td><td> 24,3</td><td> 24,9</td><td> 24,5</td><td> 13,3</td><td> 1,47</td>

N / A = Not applicable

Defect repair example

The following descriptions demonstrate exemplary methods for removing defects and polishing, using abrasive articles, tools and methods of the present invention, as well as a conventional comparative method.

TEST PANEL: A car's steel canopy with a black paint finish was prepared by spraying a colorless coat over the black paint finish. The colorless coat finish was commercially available under the trade name AUTOCLEAR III, available from Akzo Noble, Narcross, Georgia, USA, and was cured for 40 minutes at 60 ° C (140 ° F).

COMPARATIVE EXAMPLE C: The following five-step conventional repair process was performed on twelve (12) defects on a test panel. The test panel was cleaned between steps by rubbing the residual abrasive fluid with a high performance cloth (obtained under the trade name PERFECT-IT ultra performance cloth, part number 06020, available from 3M Company A clean, high performance cloth was used for the final polishing step.

Step 1 (Defect Removal): An abrasive article formed as described in comparative example B was used by applying light manual pressure, and with minimal lateral movement, to remove twelve (12) paint defects (protuberances) on the surface of the test panel described above. The sanding time used to remove all defects was 3 minutes.

Step 2 (Abrasion Refinement): A 15.2 cm (6 inch) diameter support surface, commercially available under the trade name HOOKIT II discs (part number 05251, available from 3M Company) was attached to a sander double acting, model number 21035 (from Dynabrade, Inc., Clarence, New York, USA). A 15.2 cm (6 inch) diameter interface block, available under the trade name HOOKIT II SOFT interface pad (part number 05274, available from 3M Company), has been attached to the support surface. A foam block 15.2 cm (6 inches) in diameter, available under the trade name TRIZACT HOOKIT II foam disc (part number 02075, grade P-3000, also available from 3M Company) was then fixed to the interface block. The scratches formed during the removal of defects in step 1 were refined by applying pressure to the areas containing the scratches, using a foam block, operating the double-action sander at a line pressure set to 413.7 kiloPascals (kPa) (60 pounds per square inch (psi)), with the block kept generally parallel to the test panel surface. The scratch refinement time used to refine the scratches in each of the sanded areas was 3 minutes and 30 seconds.

Step 3 (Composition): A 20.3 cm (8 inch) diameter support surface, available under the trade name PERFECT-IT support block (part number 05718, available from 3M Company), has been attached to a straightening tool 20.3 cm (8 inch) in diameter, model number DW 849, available from Dewalt Industrial Tool Corporation, Hampstead, Maryland, USA. A 22.9 cm (9 inch) diameter wool block, available under the trade name PERFECT-IT III composition block (part number 05719, available from 3M Company), has been attached to the support surface. An abrasive fluid paste commonly known as a scrubbing compound (available under the trade name PERFECT-IT 3000 EXTRA CUT rubbing compound, available from 3M Company) was applied to the sanded and refined areas of the test panel and smoothed for 8 minutes, using the wool block, operating the straightening tool at 1,800 revolutions per minute (rpm).

Step 4 (Polishing): Step 3 was repeated, except that the wool block was replaced by a 20.3 cm (8 inch) diameter polishing foam block (available under the trade name PERFECTIT polishing foam block, number of part 05725, available from 3M Company) and the abrasive slurry (wiping compound) used in step 3 was replaced by a second abrasive slurry, including finer abrasive particles (PERFECT-IT 3000 swirl marks remover, part number 06064, also available from 3M Company). The polishing step was performed for a total of six (6) minutes.

Step 5 (Swirl Elimination): Step 4 was repeated, except that the swirl mark remover from step 4 was replaced with a third abrasive fluid paste, including even finer abrasive particles (available under the trade name polisher PERFECT-IT 3000 ULTRAFINA SE, part number 06068, available from 3M Company). The polishing foam block used in step 4 has also been replaced by a different polishing foam block (available under the trade name PERFECT-IT ULTRAFINA polishing foam block, part number 05733, available from 3M Company). The swirl elimination step was performed for a total of four (4) minutes.

EXAMPLE 5: Twelve (12) defects on the surface coated with a colorless coat of a test panel were repaired using the abrasive articles and exemplary methods of the invention, in a three (3) step process, as described in the present invention. The test panel was cleaned between steps as described in connection with comparative example C.

Step 1 (Defect Removal): An abrasive article as described in example 4 was used in the rotary reciprocating tool described above. For each defect to be removed, the tool was used to sand the defect with minimal lateral movement and a sanding angle of zero degrees (ie, the abrasive surface was kept parallel to the surface of the test panel). The tool and abrasive article were used to remove twelve (12) defects (protuberances in the paint) on the test panel surface. The sanding time used to remove the twelve defects was 2.5 minutes.

Step 2 (Composition): A 2.54 cm (1 inch) diameter adapter (available under the trade name ROLOC support, part number 07500, available from 3M Company) was attached to an 18-volt cordless drill , model number BTD140, available from Makita Corp., La Mirada, California, USA. A 3.2 cm (1.25 inch) diameter support surface (available under the trade name FINESSE-IT ROLOC disc pad, type J, part number 67415, available from 3M Company) was attached to the adapter. A 3.2 cm (1.25 inch) diameter foam block (die cut from a larger PERFECT-IT polishing foam block, part number 05725, available from 3M Company) has been attached to the surface support. An abrasive fluid paste (available under the trade name PERFECT-IT 3000 swirl mark remover, part number 06064, also available from 3M Company) was applied to the sanded and smoothed areas at approximately 1,500 rpm, using the polishing. The composition stage was performed for a total of three (3) minutes.

Step 3 (Swirl Elimination): The polishing block used in step 2 has been replaced by a 2.54 cm (1 inch diameter) smoothing block (die cut from a PERFECT-IT polishing foam block ULTRAFINE greater, part number 05733 available from 3M Company) and the abrasive slurry used in step 2 has been replaced by a second abrasive slurry containing finer abrasive particles (available under the trade name PERFECT-IT 3000 ULTRAFINA SE polisher, part number 06068 , available from 3M Company). The swirl elimination step was performed by rotating the smoothing block at 1,800 rpm, for a total of 3 minutes.

EXAMPLE 6: Twelve (12) defects on the surface coated with a colorless coat of a test panel were repaired using the abrasive articles and exemplary methods of the invention, in a three (3) step process, as described in the present invention. The test panel was cleaned between steps as described in connection with comparative example C.

Step 1 (Defect Removal): Step 1 of example 5 was performed as described in example 5, except that the defect removal step was performed for a total of 2 minutes 20 seconds.

Step 2 (Composition): Step 2 of example 5 was performed as described in example 5, except that the composition step was performed for a total of 3 minutes 10 seconds.

Step 3 (Swirl Elimination): Step 5 of comparative example C was performed for a total of 2 minutes and 20 seconds.

EXAMPLE 7: Twelve (12) defects in the surface coated with a colorless coat of a test panel were repaired using the abrasive articles and exemplary methods of the invention, in a three (3) step process, as described in the present invention. The test panel was cleaned between steps as described in connection with comparative example C.

Step 1 (Defect Removal): Step 1 of example 5 was performed as described in example 5, except that the defect removal step was performed for a total of 2 minutes 30 seconds.

Step 2 (Composition): Step 2 of example 5 was performed as described in example 5, except that the drill was replaced by a double-action sander (model number 57502, available from the Dynabrade Company) operated at a line pressure adjusted to 620 kPa (90 psi). The composition step was performed for a total of 3 minutes and 15 seconds.

Step 3 (Swirl Elimination): Step 5 of comparative example C was performed, except that the double action sander from step 2 of this example was used in place of the smoothing tool used in step 5 of comparative example C The double-action sander was operated at a line pressure set to 620 kPa (90 psi). In addition, a 2.54 cm (1 inch) diameter polishing foam block was die-cut from a larger polishing block (available under the trade name PERFECT-IT ULTRAFINE polishing foam block, number of part 05733, available from 3M Company). The swirl elimination step was performed for a total of three (3) minutes.

EXAMPLE 8: Twelve (12) defects in the surface coated with a colorless coat of a test panel were repaired using the abrasive articles and exemplary methods of the invention, in a three (3) step process, as described in the present invention. The test panel was cleaned between steps as described in connection with comparative example C.

Step 1 (Removal of Defects): Step 1 described in example 5 was repeated, except for the fact that the total time was 2 minutes and 30 seconds.

Step 2 (Composition): Step 2 described in example 7 was repeated, except for the fact that the total time was 3 minutes and 5 seconds.

Step 3 (Swirl Elimination): Step 3 described in example 6 was repeated, except that the total time was 2 minutes and 10 seconds.

Results of comparative example C and give example 5 to 8:

At the end of comparative example C and examples 5 to 8, the finish of the test panel was classified visually, according to the following scale:

1: Sanding scratches still visible under commercial lighting or direct sunlight.

2: Swirls or deep opacity visible under commercial lighting or direct sunlight.

3: Swirls or opacity visible only under direct sunlight conditions.

4: Swirls or light / thin opacity visible only in direct sunlight conditions.

5: No swirl or visible opacity under commercial lighting or direct sunlight.

The panel finish ratings and the amount of time for all finishing steps are listed in table 2 below. Table 2

<td>Sample</td><td>Time</td><td>Classification of Finishing</td>

<td>Comparative A</td><td>24 minutes and 30 seconds</td><td> 5</td>

<td>Example 5</td><td>8 minutes and 30 seconds</td><td> 3</td>

<td>Example 6</td><td>7 minutes and 50 seconds</td><td> 5</td>

<td>Example 7</td><td>8 minutes 45 seconds</td><td> 3</td>

<td>Example 8</td><td>7 minutes 45 seconds</td><td> 5</td>

The complete description of the patents, patent documents, and publications cited in the background, in the detailed description of the exemplary modalities, and elsewhere in the present invention are hereby incorporated by reference, in their entirety, as if each were incorporated individually.

The illustrative modalities of this invention are discussed and references have been made to possible variations within the scope of this invention. These and other variations and modifications in the invention will become evident to those skilled in the art without departing from the scope of the invention, and it should be understood that this invention is not limited to the illustrative modalities presented here. Consequently, the invention should be limited only by the claims provided below and equivalents thereof.