U.S. patent application number 11/688497 was filed with the patent office on 2008-09-25 for abrasive article and method of making and using the same.
This patent application is currently assigned to 3M Innovative Properties Company. Invention is credited to Seyed A. Angadjivand, Yeun-Jong Chou, Mary B. Donovan, Thomas W. Rambosek, Rufus C. Sanders, Edward J. Woo.
Application Number | 20080233850 11/688497 |
Document ID | / |
Family ID | 39577882 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080233850 |
Kind Code |
A1 |
Woo; Edward J. ; et
al. |
September 25, 2008 |
ABRASIVE ARTICLE AND METHOD OF MAKING AND USING THE SAME
Abstract
An abrasive article comprises a porous abrasive member, a
nonwoven filter medium, a second nonwoven filter medium, and
optionally a porous attachment layer. A plurality of openings in
the porous abrasive member cooperates with the first nonwoven
filter medium to allow the flow of particles from an outer abrasive
surface of the porous abrasive member to the second nonwoven filter
medium. Methods of making and using the abrasive articles are
included.
Inventors: |
Woo; Edward J.; (Woodbury,
MN) ; Rambosek; Thomas W.; (Woodbury, MN) ;
Angadjivand; Seyed A.; (Woodbury, MN) ; Donovan; Mary
B.; (St. Paul, MN) ; Sanders; Rufus C.;
(Burnsville, MN) ; Chou; Yeun-Jong; (Woodbury,
MN) |
Correspondence
Address: |
3M INNOVATIVE PROPERTIES COMPANY
PO BOX 33427
ST. PAUL
MN
55133-3427
US
|
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
39577882 |
Appl. No.: |
11/688497 |
Filed: |
March 20, 2007 |
Current U.S.
Class: |
451/526 ;
51/295 |
Current CPC
Class: |
B24B 7/00 20130101; B24D
9/08 20130101; B24D 11/02 20130101; B24B 55/102 20130101 |
Class at
Publication: |
451/526 ;
51/295 |
International
Class: |
B24D 11/00 20060101
B24D011/00 |
Claims
1. An abrasive article comprising: a porous abrasive member
comprising: an abrasive layer proximate and affixed to a first
surface of a substrate, the abrasive layer comprising a plurality
of abrasive particles affixed to the first surface of the substrate
by at least one binder, wherein the abrasive layer has an outer
abrasive surface, wherein the substrate has a thickness and a
second surface opposite the first surface of the substrate, wherein
a plurality of openings extend from the outer abrasive surface to
the second surface of the substrate, and wherein the porous
abrasive member has perforations that extend through the thickness
of the substrate and have a substantially uniform cross-section
throughout their length; a unitary first nonwoven filter medium
having a first surface and a second surface opposite the first
surface, wherein the first surface of the first nonwoven filter
medium is proximate and affixed to the second surface of the
substrate, and wherein the first nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof, and a unitary second nonwoven filter medium having a first
surface and a second surface opposite the first surface, wherein
the first surface of the second nonwoven filter medium is proximate
and affixed to the second surface of the first nonwoven filter
medium, and wherein the second nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof; wherein the plurality of openings cooperate with the first
nonwoven filter medium to allow the flow of particles from the
outer abrasive surface to the second nonwoven filter medium, and
wherein, in an unused state, the at least a portion of the abrasive
article exhibits a pressure drop according to the Pressure Drop
Measurement Test in a range of from 0.2 to 20 millimeters of
water.
2. An abrasive article according to claim 1, wherein the porous
abrasive member comprises an apertured coated abrasive.
3. An abrasive article according to claim 1, wherein the porous
abrasive member comprises a screen abrasive.
4. An abrasive article according to claim 1, further comprising a
porous attachment layer proximate and affixed to the second surface
of the second nonwoven filter medium.
5. An abrasive article according to claim 4, wherein the porous
attachment layer comprises a loop portion or a hook portion of a
two-part mechanical engagement system.
6. An abrasive article according to claim 4, wherein the first
nonwoven filter medium, the second nonwoven filter medium, and the
porous attachment layer are affixed to one another by needletacking
or a stitch bond.
7. An abrasive article according to claim 1, wherein the first
nonwoven filter medium and the second nonwoven filter medium are
affixed to one another by needletacking or a stitch bond.
8. An abrasive article according to claim 1, wherein the first
nonwoven filter medium is affixed to the second nonwoven filter
medium by an adhesive.
9. An abrasive article according to claim 1, wherein at least one
of the first or second nonwoven filter medium has a peripheral edge
that is sealed along a major portion thereof.
10. (canceled)
11. An abrasive article according to claim 1, wherein at least one
of the first nonwoven filter medium or the second nonwoven filter
medium comprises a blown microfiber web.
12. An abrasive article according to claim 1, wherein at least one
of the first nonwoven filter medium or the second nonwoven filter
medium comprises an electret charge.
13. An abrasive article according to claim 1, wherein the substrate
is selected from the group consisting of metal foil, paper, fabric,
and plastic film.
14. An abrasive article according to claim 1, wherein the abrasive
article comprises an abrasive disc.
15. A method of abrading a surface of a workpiece, the method
comprising contacting the surface with an abrasive article
according to claim 1, and relatively moving the abrasive article
and the surface to mechanically modify the surface.
16. A method of making an abrasive article, the method comprising:
providing a porous abrasive member comprising: an abrasive layer
proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate, and
wherein the porous abrasive member has perforations that extend
through the thickness of the substrate and have a substantially
uniform cross-section throughout their length; providing a unitary
first nonwoven filter medium, the first nonwoven filter medium
having a first surface and a second surface opposite the first
surface, wherein the first nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof, and wherein the first surface of the first nonwoven filter
medium is proximate the second surface of the substrate; providing
a second nonwoven filter medium, the second nonwoven filter medium
having a first surface and a second surface opposite the first
surface, wherein the second nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof, and wherein the first surface of the second nonwoven
filter medium is proximate the second surface of the first nonwoven
filter medium; affixing the first nonwoven filter medium to the
second surface of the substrate; and affixing the second nonwoven
filter medium to the first nonwoven filter medium; wherein the
plurality of openings cooperate with the first nonwoven filter
medium to allow the flow of particles from the outer abrasive
surface to the second nonwoven filter medium, and wherein, in an
unused state, at least a portion of the abrasive article exhibits a
pressure drop according to the Pressure Drop Measurement Test in a
range of from 0.2 to 20 millimeters of water.
17. A method of making an abrasive article according to claim 16,
wherein the porous abrasive member comprises an apertured coated
abrasive.
18. A method of making an abrasive article according to claim 16,
wherein the porous abrasive member comprises a screen abrasive.
19. A method of making an abrasive article according to claim 16,
the method further comprising sealing a major portion of a
peripheral edge of at least one of the first or second nonwoven
filter medium.
20. A method of making an abrasive article according to claim 16,
further comprising affixing a porous attachment layer to the second
nonwoven filter medium.
21. A method of making an abrasive article according to claim 20,
wherein the porous attachment layer comprises a loop portion or a
hook portion of a two-part mechanical engagement system.
22. A method of making an abrasive article according to claim 20,
wherein the first nonwoven filter medium, the second nonwoven
filter medium, and the porous attachment layer are affixed to one
another by needletacking or a stitch bond.
23. A method of making an abrasive article according to claim 16,
wherein the first nonwoven filter medium and the second nonwoven
filter medium are affixed to one another by needletacking or a
stitch bond.
24. A method of making an abrasive article according to claim 16,
wherein the porous abrasive member is affixed to the first nonwoven
filter medium by an adhesive.
25. A method of making an abrasive article according to claim 16,
wherein the first nonwoven filter medium is affixed to the second
nonwoven filter medium by an adhesive.
26. (canceled)
27. A method of making an abrasive article according to claim 16,
wherein at least one of the first nonwoven filter medium or the
second nonwoven filter medium comprises a blown microfiber web.
28. A method of making an abrasive article according to claim 16,
wherein at least one of the first nonwoven filter medium or the
second nonwoven filter medium comprises an electret charge.
29. A method of making an abrasive article according to claim 16,
wherein the substrate is selected from the group consisting of
metal foil, paper, fabric, and plastic film.
30. A method of making an abrasive article according to claim 16,
wherein the abrasive article comprises an abrasive disc.
31. An abrasive article comprising: a porous abrasive member
comprising: an abrasive layer proximate and affixed to a first
surface of a substrate, the abrasive layer comprising a plurality
of abrasive particles affixed to the first surface of the substrate
by at least one binder, wherein the abrasive layer has an outer
abrasive surface, wherein the substrate has a thickness and a
second surface opposite the first surface of the substrate, wherein
a plurality of openings extend from the outer abrasive surface to
the second surface of the substrate, and wherein the porous
abrasive member has perforations that extend through the thickness
of the substrate and have a substantially uniform cross-section
throughout their length; a unitary first nonwoven filter medium
having a first surface and a second surface opposite the first
surface, wherein the first surface of the first nonwoven filter
medium is proximate and affixed to the second surface of the
substrate, wherein the first nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof, and wherein the first nonwoven filter medium has a
thickness of from 1 to 25 millimeters and a density of from 0.04 to
0.5 grams per cubic centimeter; and a unitary second nonwoven
filter medium having a first surface and a second surface opposite
the first surface, wherein the first surface of the second nonwoven
filter medium is proximate and affixed to the second surface of the
first nonwoven filter medium, wherein the second nonwoven filter
medium comprises a plurality of synthetic fibers selected from the
group consisting of polypropylene fibers, polyester fibers, nylon
fibers, and mixtures thereof, and wherein the second nonwoven
filter medium has a thickness of from 0.5 to 15 millimeters and a
bulk density of from 0.04 to 0.5 grams per cubic centimeter; and
wherein the plurality of openings cooperate with the first nonwoven
filter medium to allow the flow of particles from the outer
abrasive surface to the second nonwoven filter medium.
32. An abrasive article according to claim 31, wherein the porous
abrasive member comprises an apertured coated abrasive.
33. An abrasive article according to claim 31, wherein the porous
abrasive member comprises a screen abrasive.
34. An abrasive article according to claim 31, further comprising a
porous attachment layer proximate and affixed to the second surface
of the second nonwoven filter medium.
35. An abrasive article according to claim 34, wherein the porous
attachment layer comprises a loop portion or a hook portion of a
two-part mechanical engagement system.
36. An abrasive article according to claim 34, wherein the first
nonwoven filter medium, the second nonwoven filter medium, and the
porous attachment layer are affixed to one another by needletacking
or a stitch bond.
37. An abrasive article according to claim 31, wherein the first
nonwoven filter medium and the second nonwoven filter medium are
affixed to one another by needletacking or a stitch bond.
38. An abrasive article according to claim 31, wherein the porous
abrasive member is affixed to the first nonwoven filter medium by
an adhesive.
39. An abrasive article according to claim 31, wherein the first
nonwoven filter medium is affixed to the second nonwoven filter
medium by an adhesive.
40. An abrasive article according to claim 31, wherein at least one
of the first or second nonwoven filter medium has a peripheral edge
that is sealed along a major portion thereof.
42. (canceled)
43. An abrasive article according to claim 31, wherein at least one
of the first nonwoven filter medium or the second nonwoven filter
medium comprises a blown microfiber web.
44. An abrasive article according to claim 31, wherein at least one
of the first nonwoven filter medium or the second nonwoven filter
medium comprises an electret charge.
45. An abrasive article according to claim 31, wherein the
substrate is selected from the group consisting of metal foil,
paper, fabric, and plastic film.
46. An abrasive article according to claim 31, wherein the abrasive
article comprises an abrasive disc.
47. A method of abrading a surface of a workpiece, the method
comprising contacting the surface with an abrasive article
according to claim 31, and relatively moving the abrasive article
and the surface to mechanically modify the surface.
48. A method of making an abrasive article, the method comprising:
providing a porous abrasive member comprising: an abrasive layer
proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate, and
wherein the porous abrasive member has perforations that extend
through the thickness of the substrate and have a substantially
uniform cross-section throughout their length; providing a unitary
first nonwoven filter medium having a first surface and a second
surface opposite the first surface, wherein the first surface of
the first nonwoven filter medium is proximate the second surface of
the substrate, wherein the first nonwoven filter medium comprises a
plurality of synthetic fibers selected from the group consisting of
polypropylene fibers, polyester fibers, nylon fibers, and mixtures
thereof, and wherein the first nonwoven filter medium has a
thickness of from 1 to 25 millimeters and a bulk density of from
0.04 to 0.5 grams per cubic centimeter: providing a unitary second
nonwoven filter medium having a first surface and a second surface
opposite the first surface, wherein the first surface of the second
nonwoven filter medium is proximate the second surface of the first
nonwoven filter medium, wherein the second nonwoven filter medium
comprises a plurality of synthetic fibers selected from the group
consisting of polypropylene fibers, polyester fibers, nylon fibers,
and mixtures thereof, wherein the second nonwoven filter medium has
a thickness of from 0.5 to 15 millimeters and a bulk density of
from 0.04 to 0.5 grams per cubic centimeter; affixing the first
nonwoven filter medium to the second surface of the substrate; and
affixing the second nonwoven filter medium to the first nonwoven
filter medium, wherein the plurality of openings cooperate with the
first nonwoven filter medium to allow the flow of particles from
the outer abrasive surface to the second nonwoven filter
medium.
49. A method of making an abrasive article according to claim 48,
wherein the porous abrasive member comprises an apertured coated
abrasive.
50. A method of making an abrasive article according to claim 48,
wherein the porous abrasive member comprises a screen abrasive.
51. A method of making an abrasive article according to claim 48,
the method further comprising sealing a major portion of a
peripheral edge of at least one of the first or second nonwoven
filter medium.
52. A method of making abrasive article according to claim 48,
further comprising affixing a porous attachment layer to the second
nonwoven filter medium.
53. A method of making abrasive article according to claim 52,
wherein the porous attachment layer comprises a loop portion or a
hook portion of a two-part mechanical engagement system.
54. A method of making an abrasive article according to claim 52,
wherein the first nonwoven filter medium, the second nonwoven
filter medium, and the porous attachment layer are affixed to one
another by needletacking or a stitch bond.
55. A method of making an abrasive article according to claim 48,
wherein the first nonwoven filter medium and the second nonwoven
filter medium are affixed to one another by needletacking or a
stitch bond.
56. A method of making an abrasive article according to claim 48,
wherein the porous abrasive member is affixed to the first nonwoven
filter medium by an adhesive.
57. A method of making an abrasive article according to claim 48,
wherein the first nonwoven filter medium is affixed to the second
nonwoven filter medium by an adhesive.
58. (canceled)
59. A method of making an abrasive article according to claim 48,
wherein at least one of the first nonwoven filter medium or the
second nonwoven filter medium comprises a blown microfiber web.
60. A method of making an abrasive article according to claim 48,
wherein at least one of the first nonwoven filter medium or the
second nonwoven filter medium comprises an electret charge.
61. A method of making an abrasive article according to claim 48,
wherein the substrate is selected from the group consisting of
metal foil, paper, fabric, and plastic film.
62. A method of making an abrasive article according to claim 48,
wherein the abrasive article comprises an abrasive disc.
Description
BACKGROUND
[0001] Abrasive articles are used in industry for abrading,
grinding, and polishing applications. They may be obtained in a
variety of converted forms, such as belts, discs, sheets, and the
like, in many different sizes.
[0002] Generally, when using abrasives articles in the form of
"sheet goods" (i.e., discs and sheets), a back-up pad is used to
mount or attach the abrasive article to the abrading tool. One type
of back-up pad has dust collection holes connected by a series of
grooves. The dust collection holes are typically connected to a
vacuum source to help control particles such as, for example, swarf
(as used herein, the term "swarf" refers loose material such as
dust and debris generated during abrading processes) build-up on
the abrading surface of the abrasive article. Removing swarf from
the abrading surface is known to improve the performance of the
abrasive article.
[0003] Some abrasive tools have integral vacuum systems with dust
collection means. The extracting and holding capabilities of these
abrasive tools have been limited, in part, due to the suction
requirements of current abrasive disks that their related back-up
pads require.
[0004] In some abrasive tool configurations, dust is collected in a
complex collection system through a hose connected to the abrasive
tools. Dust collection systems, however, are not always available
for the abrasive tool operator. Further, the use of dust collection
systems requiring hoses may be cumbersome and may interfere with
the operator's manipulation of the abrasive tool.
SUMMARY
[0005] In one aspect, the present invention provides an abrasive
article comprising:
[0006] a porous abrasive member comprising: an abrasive layer
proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, and wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate;
[0007] a first nonwoven filter medium having a first surface and a
second surface opposite the first surface, wherein the first
surface of the first nonwoven filter medium is proximate and
affixed to the second surface of the substrate, wherein the first
nonwoven filter medium comprises a plurality of fibers; and
[0008] a second nonwoven filter medium having a first surface and a
second surface opposite the first surface, wherein the first
surface of the second nonwoven filter medium is proximate and
affixed to the second surface of the first nonwoven filter medium,
and wherein the second nonwoven filter medium comprises a plurality
of fibers;
[0009] wherein the plurality of openings cooperate with the first
nonwoven filter medium to allow the flow of particles from the
outer abrasive surface to the second nonwoven filter medium, and
wherein, in an unused state, the at least a portion of the abrasive
article exhibits a pressure drop according to the Pressure Drop
Measurement Test in a range of from 0.2 to 20 millimeters of
water.
[0010] In another aspect, the present invention provides a method
of making an abrasive article, the method comprising:
[0011] providing a porous abrasive member comprising: an abrasive
layer proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, and wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate;
[0012] providing a first nonwoven filter medium, the first nonwoven
filter medium having a first surface and a second surface opposite
the first surface, wherein the first nonwoven filter medium
comprises a plurality of fibers, and wherein the first surface of
the first nonwoven filter medium is proximate the second surface of
the substrate;
[0013] providing a second nonwoven filter medium, the second
nonwoven filter medium having a first surface and a second surface
opposite the first surface, wherein the second nonwoven filter
medium comprises a plurality of fibers, and wherein the first
surface of the second nonwoven filter medium is proximate the
second surface of the first nonwoven filter medium;
[0014] affixing the first nonwoven filter medium to the second
surface of the substrate; and
[0015] affixing the second nonwoven filter medium to the first
nonwoven filter medium;
[0016] wherein the plurality of openings cooperate with the first
nonwoven filter medium to allow the flow of particles from the
outer abrasive surface to the second nonwoven filter medium, and
wherein, in an unused state, at least a portion of the abrasive
article exhibits a pressure drop according to the Pressure Drop
Measurement Test in a range of from 0.2 to 20 millimeters of
water.
[0017] In yet another aspect, the present invention provides an
abrasive article comprising:
[0018] a porous abrasive member comprising: an abrasive layer
proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, and wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate;
[0019] a first nonwoven filter medium having a first surface and a
second surface opposite the first surface, wherein the first
surface of the first nonwoven filter medium is proximate and
affixed to the second surface of the substrate, wherein the first
nonwoven filter medium comprises a plurality of fibers, and wherein
the first nonwoven filter medium has a thickness of from 1 to 25
millimeters and a bulk density of from 0.04 to 0.5 grams per cubic
centimeter; and
[0020] a second nonwoven filter medium having a first surface and a
second surface opposite the first surface, wherein the first
surface of the second nonwoven filter medium is proximate and
affixed to the second surface of the first nonwoven filter medium,
wherein the second nonwoven filter medium comprises a plurality of
fibers, and wherein the second nonwoven filter medium has a
thickness of from 0.5 to 15 millimeters and a bulk density of from
0.04 to 0.5 grams per cubic centimeter; and
[0021] wherein the plurality of openings cooperate with the first
nonwoven filter medium to allow the flow of particles from the
outer abrasive surface to the second nonwoven filter medium.
[0022] In yet another aspect the present invention provides a
method of making an abrasive article, the method comprising:
[0023] providing a porous abrasive member comprising: an abrasive
layer proximate and affixed to a first surface of a substrate, the
abrasive layer comprising a plurality of abrasive particles affixed
to the first surface of the substrate by at least one binder,
wherein the abrasive layer has an outer abrasive surface, wherein
the substrate has a second surface opposite the first surface of
the substrate, and wherein a plurality of openings extend from the
outer abrasive surface to the second surface of the substrate;
[0024] providing a first nonwoven filter medium having a first
surface and a second surface opposite the first surface, wherein
the first surface of the first nonwoven filter medium is proximate
the second surface of the substrate, wherein the first nonwoven
filter medium comprises a plurality of fibers, and wherein the
second nonwoven filter medium has a thickness of from 0.5 to 15
millimeters and a bulk density of from 0.04 to 0.5 grams per cubic
centimeter;
[0025] providing a second nonwoven filter medium having a first
surface and a second surface opposite the first surface, wherein
the first surface of the second nonwoven filter medium is proximate
the second surface of the first nonwoven filter medium, wherein the
second nonwoven filter medium comprises a plurality of fibers,
wherein the second nonwoven filter medium has a thickness of from
0.5 to 15 millimeters and a bulk density of from 0.04 to 0.5 grams
per cubic centimeter;
[0026] affixing the first nonwoven filter medium to the second
surface of the substrate; and
[0027] affixing the second nonwoven filter medium to the first
nonwoven filter medium,
[0028] wherein the plurality of openings cooperate with the first
nonwoven filter medium to allow the flow of particles from the
outer abrasive surface to the second nonwoven filter medium.
[0029] In certain embodiments, the porous abrasive member comprises
an apertured coated abrasive. In certain embodiments, the porous
abrasive member comprises a screen abrasive. In certain
embodiments, the first nonwoven filter medium and the second
nonwoven filter medium are affixed to one another by needletacking
or a stitch bond. In certain embodiments, the porous abrasive
member is affixed to the first nonwoven filter medium by an
adhesive. In certain embodiments, the first nonwoven filter medium
is affixed to the second nonwoven filter medium by an adhesive. In
certain embodiments, at least one of the first nonwoven filter
medium or the second nonwoven filter medium comprise synthetic
fibers selected from the group consisting of polypropylene fibers,
polyester fibers, nylon fibers, and mixtures thereof. In certain
embodiments, the substrate is selected from the group consisting of
metal foil, paper, fabric, and plastic film. In certain
embodiments, at least one of the first nonwoven filter medium or
the second nonwoven filter medium comprises a blown microfiber web.
In certain embodiments, at least one of the first nonwoven filter
medium or the second nonwoven filter medium comprises an electret
charge. In certain embodiments, the second surface of the substrate
and the first surface of the first nonwoven filter medium are
coextensive, and the second surface of the first nonwoven filter
medium and the first surface of the second nonwoven filter medium
are coextensive. In certain embodiments, at least one of the first
or second nonwoven filter medium has a peripheral edge that is
sealed along a major portion thereof. In certain embodiments, the
abrasive article comprises an abrasive disc.
[0030] In certain embodiments, a porous attachment layer is affixed
to the second surface of the second nonwoven filter medium. In
certain embodiments, the porous attachment layer comprises a loop
portion or a hook portion of a two-part mechanical engagement
system. In certain embodiments, the first nonwoven filter medium,
the second nonwoven filter medium, and the porous attachment layer
are affixed to one another by needletacking or a stitch bond.
[0031] Abrasive articles according to the present invention are
useful, for example, for abrading a surface of a workpiece by a
method comprising contacting the surface with the abrasive article,
and relatively moving the abrasive article and the surface to
mechanically modify the surface.
[0032] Advantageously, abrasive articles according to the present
invention are particularly suitable for use in those abrading
applications generating appreciable amounts of particles (e.g.,
swarf), and in at least some embodiments, may effectively trap at
least 40, 50 (i.e., a majority), 60, 70, 80, or even more than 90
percent of particles generated in such abrading applications, for
example, if used in combination with a tool having a vacuum
source.
[0033] As used herein,
[0034] the term "air resistance" refers to resistance of air
passing through the thickness dimension of a nonwoven web or
abrasive article, and, when used for comparison purposes, all air
resistance values are to be measured under like conditions;
[0035] the term "nonwoven filter medium" refers to a material,
having internal void space and formed substantially of a plurality
of entangled and/or bonded fibers, produced by a process other than
weaving or knitting; and
[0036] the term "thickness" as applied to a nonwoven filter medium
refers to the thickness of the nonwoven web as measured according
to ASTM D5736-95 (Reapproved 2001) "Standard Test Method for
Thickness of Highloft Nonwoven Fabrics" using a pressure plate
force of 0.002 pound per square inch (13.8 Pa).
BRIEF DESCRIPTION OF THE DRAWING
[0037] FIG. 1A is a perspective view of an exemplary abrasive
article according to one embodiment of the present invention,
partially cut away to reveal the layers forming the article;
[0038] FIG. 1B is a schematic cross-sectional view of the abrasive
article shown in FIG. 1A;
[0039] FIG. 2A is a top view of an exemplary porous abrasive member
useful in abrasive articles according to the present invention;
[0040] FIG. 2B is a cross-sectional view of the porous abrasive
member shown in FIG. 2A;
[0041] FIG. 3 is a top view of an exemplary porous abrasive member
useful in abrasive articles according to the present invention,
partially cut away to reveal the components forming the abrasive
layer; and
[0042] FIG. 4 is a scale top view showing an exemplary perforation
pattern 400 for a 5-inch diameter coated abrasive disc.
[0043] These figures, which are idealized, are intended to be
merely illustrative of the abrasive article of the present
invention and non-limiting.
DETAILED DESCRIPTION
[0044] FIG. 1A shows a perspective view of an exemplary abrasive
article 102 (shown as an abrasive disc) with a partial cutaway. As
shown in FIG. 1A, the abrasive article 102 has a porous abrasive
member 104, a first nonwoven filter medium 120, a second nonwoven
filter medium 140, and an optional porous attachment layer 146. The
porous abrasive member 104 comprises a plurality of openings that
allow the flow of particles (e.g., swarf generated during an
abrading process) through the porous abrasive member 104. Particles
are then captured by the filter medium within the abrasive article.
Optional seal 105 seals the peripheral edge 106 (shown in FIG. 1B)
of first and second nonwoven filter medium 120, 140, respectively,
thereby preventing lateral escape of particles not retained by the
abrasive article 102.
[0045] FIG. 1B shows a schematic cross-sectional view of the
abrasive article 102 shown in FIG. 1A. As shown in FIG. 1B, the
abrasive article 102 comprises multiple layers. The first nonwoven
filter medium 120 comprises a first surface 122 and a second
surface 124 opposite the first surface 122. The second nonwoven
filter medium 140 comprises a first surface 142 and a second
surface 144 opposite the first surface 142. The first surface 122
of the first nonwoven filter medium 120 is proximate the porous
abrasive member 104. The second surface 124 of the first nonwoven
filter medium 120 is proximate the first surface 142 of the second
nonwoven filter medium 140. A porous attachment layer 146 is
proximate the second surface 144 of the second nonwoven filter
medium 140.
[0046] The porous abrasive member and various filter medium layers
of the abrasive article are affixed to one another in a manner that
does not prevent the flow of particles from one layer to the next,
although some partial or minor obstruction(s) to particle flow may
be present. In some embodiments, the porous abrasive member and
various filter medium layers of the abrasive article are affixed to
one another in a manner that does not substantially inhibit the
flow of particles from one layer to the next. In some embodiments,
the level of particle flow through the abrasive article may be
restricted, at least in part, by the introduction of an adhesive
between the porous abrasive member and the first nonwoven filter
medium, or the first nonwoven filter medium and the second nonwoven
filter medium. The level of restriction may be minimized by
applying the adhesive between layers in a discontinuous fashion
such as for example, as discrete adhesive areas (e.g., atomized
spray or starved extrusion die) or distinct adhesive lines (e.g.,
hot melt swirl-spray or patterned roll coater).
[0047] FIG. 2A shows a top view of an exemplary coated abrasive
material used to form the porous abrasive member. FIG. 2B shows a
cross-sectional view of a section of the porous abrasive member
shown in FIG. 2A. As shown in FIG. 2B, the porous abrasive member
204 comprises a substrate 206 having a first surface 208 and a
second surface 210, a make coat 214, a plurality of abrasive
particles 212, and a size coat 215. As shown in FIG. 2A, the porous
abrasive member 204 comprises a plurality of apertures 216 (not
shown in FIG. 2B).
[0048] FIG. 3 shows a top view of an exemplary screen abrasive
material used to form the porous abrasive member. FIG. 3 includes a
partial cutaway to reveal the components forming the abrasive
layer. As shown in FIG. 3, the porous abrasive member 304 comprises
an open mesh substrate 306, a make coat 314, a plurality of
abrasive particles 312, and a size coat 315. The porous abrasive
member 304 comprises a plurality of openings 316 that extend
through the porous abrasive member. The openings 316 are formed by
openings 318 in the open mesh substrate 306.
[0049] The open mesh substrate may be made from any porous material
including, for example, perforated films, nonwovens, or woven or
knitted fabrics. In the embodiment shown in FIG. 3, the open mesh
substrate 306 is a perforated film. The film for the substrate may
be made from metal, paper, or plastic, including molded
thermoplastic materials and molded thermoset materials. In some
embodiments, the open mesh substrate comprises perforated or slit
and stretched sheet materials. In some embodiments, the open mesh
substrate comprises fiberglass, nylon, polyester, polypropylene, or
aluminum.
[0050] The openings 318 in the open mesh substrate 306 may be
generally square shaped as shown in FIG. 3. In other embodiments,
the shape of the openings may be other geometric shapes including,
for example, a rectangular shape, a circular shape, an oval shape,
a triangular shape, a parallelogram shape, a polygon shape, or a
combination of these shapes. The openings 318 in the open mesh
substrate 306 may be uniformly sized and positioned as shown in
FIG. 3. In other embodiments, the openings may be placed
non-uniformly by, for example, using a random opening placement
pattern, varying the size or shape of the openings, or any
combination of random placement, random shapes, and random
sizes.
[0051] In another aspect, a screen abrasive with a woven or knitted
substrate may be used to form the porous abrasive member. A woven
substrate typically comprises a plurality of generally parallel
warp elements that extend in a first direction and a plurality of
generally parallel weft elements that extend in a second direction.
The weft elements and warp elements of the open mesh substrate
intersect to form a plurality of openings. The second direction may
be perpendicular to the first direction to form square shaped
openings in the woven open mesh substrate. In some embodiments, the
first and second directions intersect to form a diamond pattern.
The shape of the openings may be other geometric shapes including,
for example, a rectangular shape, a circular shape, an oval shape,
a triangular shape, a parallelogram shape, a polygon shape, or a
combination of these shapes. In some embodiments, the warp and weft
elements are yarns that are woven together in a one-over-one
weave.
[0052] The warp and weft elements may be combined in any manner
known to those in the art including, for example, weaving,
stitch-bonding, or adhesive bonding. The warp and weft elements may
be fibers, filaments, threads, yarns or a combination thereof. The
warp and weft elements may be made from a variety of materials
known to those skilled in the art including, for example, synthetic
fibers, natural fibers, glass fibers, and metal. In some
embodiments, the warp and weft elements comprise monofilaments of
thermoplastic material or metal wire. In some embodiments, the
woven open mesh substrate comprises nylon, polyester, or
polypropylene.
[0053] The porous abrasive member, whether a screen abrasive, a
perforated coated abrasive, or otherwise, may comprise openings
having different open areas. The "open area" of an opening in the
porous abrasive member refers to the area of the opening as
measured over the thickness of the porous abrasive member (i.e.,
the area bounded by the perimeter of material forming the opening
through which a three-dimensional object could pass). Useful porous
abrasive members typically have an average open area of at least
about 0.5 square millimeters per opening. In some embodiments, the
porous abrasive member has an average open area of at least about
one square millimeter per opening. In yet further embodiments, the
porous abrasive member has an average open area of at least about
1.5 square millimeters per opening.
[0054] The porous abrasive member, whether woven, perforated or
otherwise, comprises a total open area that affects the amount of
air that may pass through the porous abrasive member as well as the
effective area and performance of the abrasive layer. The "total
open area" of the porous abrasive member refers to the cumulative
open areas of the openings as measured over the area formed by the
perimeter of the porous abrasive member. Porous abrasive members
have a total open area of at least about 0.01 square centimeters
per square centimeter of the abrasive layer (i.e., 1 percent open
area). In some embodiments, the porous abrasive member has a total
open area of at least about 0.03 square centimeters per square
centimeter of the abrasive layer (i.e., 3 percent open area). In
yet further embodiments, the porous abrasive member has a total
open area of at least about 0.05 square centimeters per square
centimeter of the abrasive layer (i.e., 5 percent open area).
[0055] Typically, the porous abrasive member has a total open area
that is less than about 0.95 square centimeters per square
centimeter of the abrasive layer (i.e., 95 percent open area). In
some embodiments, the porous abrasive member has a total open area
that is less than about 0.9 square centimeters per square
centimeter of the abrasive layer (i.e., 90 percent open area). In
yet further embodiments, the porous abrasive member has a total
open area that is less than about 0.80 square centimeters per
square centimeter of the abrasive layer (i.e., 80 percent open
area).
[0056] As discussed above, the porous abrasive member, whether a
perforated coated abrasive, a coated screen abrasive, a nonwoven
abrasive, or otherwise, comprises a plurality of abrasive particles
and at least one binder. In some embodiments, the abrasive layer
comprises a make coat, a size coat, a supersize coat, or a
combination thereof. In some embodiments, the abrasive layer is
provided, at least in part, by curing a slurry coat comprising
abrasive particles in a binder precursor. Typically, a make layer
of a coated abrasive is prepared by coating at least a portion of a
substrate (e.g., a treated or untreated backing, open mesh, or
nonwoven fiber web) with a make layer precursor comprising a first
binder precursor.
[0057] The substrate may have one or more treatments (e.g., a
backsize, presize, saturant, or subsize) thereon. Suitable
substrates are widely known in the abrasive arts and may consist
of, for example, metal foil, paper, fabric (e.g., knits, nonwovens,
or wovens (including open scrims and tightly woven fabrics), woven
mesh (e.g., scrim), plastic film (e.g., including thermoplastic
materials such as polyester, polyethylene, and polypropylene), and
combinations thereof. In some embodiments, the substrate does not
have a laminate structure.
[0058] The substrate is preferably relatively thin and flexible.
For example, in some embodiments, the substrate may have a
thickness of less than 1 millimeter, less than 0.5 millimeter, or
even less than 0.1 millimeter. In some embodiments, the
perforations, holes, or other porous features extending through the
thickness of the substrate have a substantially uniform
cross-section throughout their length.
[0059] Abrasive particles are then at least partially embedded
(e.g., by electrostatic or drop coating) to the make layer
precursor comprising a first binder precursor, and the make layer
precursor is at least partially cured. Electrostatic coating of the
abrasive particles typically provides erectly oriented abrasive
particles. In the context of the abrasive articles, the term
"erectly oriented" refers to a characteristic in which the longer
dimensions of a majority of the abrasive particles are oriented
substantially perpendicular (i.e., between 60 and 120 degrees) to
the substrate. Other techniques for erectly orienting abrasive
particles may also be used.
[0060] Next, the size layer is prepared by coating at least a
portion of the make layer and abrasive particles with a size layer
precursor comprising a second binder precursor (which may be the
same as, or different from, the first binder precursor), and at
least partially curing the size layer precursor. In some coated
abrasive articles, a supersize is applied to at least a portion of
the size layer. If present, the supersize layer typically includes
grinding aids and/or anti-loading materials.
[0061] Typically, a binder is formed by curing (e.g., by thermal
means, or by using electromagnetic or particulate radiation) a
binder precursor. Useful binder precursors suitable for use in
make, size, supersize, and slurry coats are well known in the
abrasive art and include, for example, free-radically polymerizable
monomer and/or oligomer, epoxy resins, acrylic resins, urethane
resins, phenolic resins, urea-formaldehyde resins,
melamine-formaldehyde resins, aminoplast resins, cyanate resins, or
combinations thereof. Useful binder precursors include thermally
curable resins and radiation curable resins, which may be cured,
for example, thermally and/or by exposure to radiation.
[0062] As is well known in the art, catalysts, initiators, and/or
curatives may be used in combination with binder precursors,
typically in an effective amount.
[0063] Suitable abrasive particles for the coated abrasives
include, for example, any known abrasive particles or materials
commonly used in abrasive articles. Examples of useful abrasive
particles for coated abrasives include, for example, fused aluminum
oxide, heat treated aluminum oxide, white fused aluminum oxide,
black silicon carbide, green silicon carbide, titanium diboride,
boron carbide, tungsten carbide, titanium carbide, diamond, cubic
boron nitride, garnet, fused alumina zirconia, sol gel abrasive
particles, silica, iron oxide, chromia, ceria, zirconia, titania,
silicates, metal carbonates (such as calcium carbonate (e.g.,
chalk, calcite, marl, travertine, marble and limestone), calcium
magnesium carbonate, sodium carbonate, magnesium carbonate), silica
(e.g., quartz, glass beads, glass bubbles and glass fibers)
silicates (e.g., talc, clays, (montmorillonite) feldspar, mica,
calcium silicate, calcium metasilicate, sodium aluminosilicate,
sodium silicate) metal sulfates (e.g., calcium sulfate, barium
sulfate, sodium sulfate, aluminum sodium sulfate, aluminum
sulfate), gypsum, aluminum trihydrate, graphite, metal oxides
(e.g., tin oxide, calcium oxide), aluminum oxide, titanium dioxide
and metal sulfites (e.g., calcium sulfite), metal particles (e.g.,
tin, lead, copper), plastic abrasive particles formed from a
thermoplastic material (e.g., polycarbonate, polyetherimide,
polyester, polyethylene, polysulfone, polystyrene,
acrylonitrile-butadiene-styrene block copolymer, polypropylene,
acetal polymers, polyvinyl chloride, polyurethanes, nylon), plastic
abrasive particles formed from crosslinked polymers (e.g., phenolic
resins, aminoplast resins, urethane resins, epoxy resins,
melamine-formaldehyde, acrylate resins, acrylated isocyanurate
resins, urea-formaldehyde resins, isocyanurate resins, acrylated
urethane resins, acrylated epoxy resins), and combinations thereof.
The abrasive particles may also be agglomerates or composites that
include additional components, such as, for example, a binder.
Criteria used in selecting abrasive particles used for a particular
abrading application typically include: abrading life, rate of cut,
substrate surface finish, grinding efficiency, and product
cost.
[0064] Coated abrasive members may further comprise optional
additives such as abrasive particle surface modification additives,
coupling agents, plasticizers, fillers, expanding agents, fibers,
antistatic agents, initiators, suspending agents, photosensitizers,
lubricants, wetting agents, surfactants, pigments, dyes, UV
stabilizers, and suspending agents. The amounts of these materials
are selected to provide the properties desired. Additives may also
be incorporated into the binder, applied as a separate coating,
held within the pores of the agglomerate, or combinations of the
above.
[0065] If not inherently porous (e.g., due to the nature of the
substrate), the abrasive member may be perforated, for example, by
mechanical perforation (e.g., die punching), laser perforation, any
other suitable technique. Any pattern of perforations may be used.
Perforations may be, for example, round or oblong, straight,
arcuate, or some complex shape. There should be sufficient porosity
of the porous abrasive member to allow particles (e.g., swarf) to
flow from the outer abrasive surface to the first and second filter
medium at a rate comparable to that at which they are
generated.
[0066] Examples of commercially available apertured coated abrasive
articles suitable for use as a porous abrasive member include
material available under the trade designation "NORTON MULTI-AIR",
from Saint-Gobain Abrasives GmbH, Wesseling, Germany, and coated
abrasive discs available under the trade designation "CLEAN SANDING
DISC" from 3M Company, Saint Paul. Minn.
[0067] In some embodiments, the first and/or second nonwoven filter
media have an average thickness in a range of at least 0.5, 1, or
even at least 5 millimeters up to 10 or 15 millimeters. In other
embodiments, the first nonwoven filter medium may have a thickness
of up to 20, or even 30 millimeters, or more. In some embodiments,
the first nonwoven filter medium has an average thickness that is
less than about 20 millimeters.
[0068] In some embodiments, the first and/or second nonwoven filter
media have a bulk density of from 0.04 to 0.5 grams per cubic
centimeter (g/cm.sup.3). For example, the first filter medium may
have a bulk density of from 0.75 to 0.4 g/cm.sup.3, or from 1 to
0.3 g/cm.sup.3.
[0069] In some embodiments, the first filter medium is thicker and
optionally less dense than the second filter medium. In other
embodiments, the second filter medium is thicker and optionally
less dense than the first filter medium.
[0070] The first and/or second filter medium of the abrasive
article may be electrostatically charged. Electrostatic charging
enhances the filter media's ability to remove particulate matter
from a fluid stream by increasing the attraction between particles
and the surface of the filter medium. Non-impinging particles
passing close to fibers of the filter media are more readily pulled
from the fluid stream, and impinging particles are adhered more
strongly. Passive electrostatic charging is provided by an
electret, which is a dielectric material that exhibits a
semi-permanent or permanent electrical charge. Electret chargeable
polymeric materials include nonpolar polymers such as
polytetrafluoroethylene (PTFE) and polypropylene.
[0071] Several methods are used to charge dielectric materials, any
of which may be used to charge the filtration medium of the
abrasive article, including corona discharge, heating and cooling
the material in the presence of a charged field, contact
electrification, spraying the web with charged particles, and
impinging a surface with water jets or water droplet streams. In
addition, the chargeability of the surface may be enhanced by the
use of blended materials. Examples of charging methods are
disclosed in U.S. Pat. Nos. RE 30,782 (van Turnhout et al.); RE
31,285 (van Turnhout et al.); 5,496,507 (Angadjivand et al.);
5,472,481 (Jones et al.); 4,215,682 (Kubik et al.); 5,057,710
(Nishiura et al.); and 4,592,815 (Nakao); 5,976,208 (Rousseau et
al.).
[0072] Each of the first and/or second nonwoven filter media
comprise a plurality of fibers.
[0073] In some embodiments, the first and/or second nonwoven filter
media comprise materials having a fiber size that is less than
about 100 microns in diameter, and sometimes less than about 50
microns, and sometimes less than about 1 micron in diameter.
[0074] The first and/or second nonwoven filter media may be made
from a wide variety of organic polymeric materials, including
mixtures and blends. Suitable filter medium includes a wide range
of materials commercially available. They include polyolefins, such
as polypropylene, linear low density polyethylene, poly-1-butene,
poly(4-methyl-1-pentene), polytetrafluoroethylene,
polychlorotrifluoroethylene; or polyvinyl chloride; aromatic
polyarenes, such as polystyrene; polycarbonates; polyesters; and
combinations thereof (including blends or copolymers). In some
embodiments, materials include polyolefins free of branched alkyl
radicals and copolymers thereof. In yet further embodiments,
materials include thermoplastic fiber formers (e.g., polyolefins
such as polyethylene, polypropylene, copolymers thereof, etc.).
Other suitable materials include: thermoplastic polymers such as
polylactic acid (PLA); non-thermoplastic fibers such as cellulose,
rayon, acrylic, and modified acrylic (halogen modified acrylic);
polyamide or polyimide fibers such as those available under the
trade designations "NOMEX" and "KEVLAR" from E.I. du Pont de
Nemours & Co., Wilmington, Del.; and fiber blends of different
polymers.
[0075] The nonwoven filter media may be formed in a web by
conventional nonwoven techniques including, for example, melt
blown, spunbond, carding, air laying (dry laying), or wet laying
techniques. Details concerning blown microfiber webs and methods
for their manufacture are well known in the art and may be found,
for example, in U.S. Pat. Nos. 6,139,308 (Berrigan et al.) and
5,496,507 (Angadjivand et al.). Exemplary melt blown nonwoven
filter media include bimodal blown microfiber media, for example,
as described in U.S. patent application Ser. No. 11/461,136 to
Brandner et al., filed Jul. 31, 2006.
[0076] If desired, the nonwoven filter medium may have a gradient
density, for example, as prepared by contacting a thermoformable
nonwoven web with a hot can.
[0077] If desired, the fibers or webs may be charged by known
methods, including, for example, by use of corona discharge
electrodes or high-intensity electric fields. The fibers may be
charged during fiber formation, prior to or while forming the
fibers into the filter web or subsequent to forming the filter web.
The fibers forming the second filter medium may even be charged
subsequent to being joined to the first nonwoven filter medium. The
second nonwoven filter medium may comprise fibers coated with a
polymer binder or adhesive, including pressure sensitive
adhesives.
[0078] The porous attachment layer allows air to pass through. The
porous attachment layer may comprise a layer of adhesive, a fabric,
a sheet material, a molded body, or a combination thereof. The
sheet material may comprise, for example, a loop portion or a hook
portion of a two-part mechanical engagement system. The porous
attachment layer may comprise a layer of pressure sensitive
adhesive with an optional release liner to protect it during
handling.
[0079] In some embodiments, the porous attachment layer comprises a
nonwoven, woven, or knitted loop material. The loop material may be
used to affix the abrasive article to a back-up pad having a
complementary mating component.
[0080] Suitable materials for a loop porous attachment layer
include both woven and nonwoven materials. Woven and knit porous
attachment layer materials may have loop-forming filaments or yarns
included in their fabric structure to form upstanding loops for
engaging hooks. Nonwoven loop attachment interface materials may
have loops formed by the interlocking fibers. In some nonwoven loop
attachment interface materials, the loops are formed by stitching a
yarn through the nonwoven web to form upstanding loops.
[0081] Useful nonwovens suitable for use as a loop porous
attachment layer include, for example, airlaids, spunbonds,
spunlaces, bonded melt blown webs, and bonded carded webs. The
nonwoven materials may be bonded in a variety of ways known to
those skilled in the art including, for example, needle-punching,
stitchbonding, hydroentangling, chemical bonding, thermal bonding,
and combinations thereof. The woven or nonwoven materials used may
be made from natural fibers (e.g., wood or cotton fibers),
synthetic fibers (e.g., polyester or polypropylene fibers) or
combinations of natural and synthetic fibers. In some embodiments,
the porous attachment layer comprises nylon, polyester or
polypropylene.
[0082] In some embodiments, a loop porous attachment layer having
an open structure that does not significantly interfere with the
flow of air through it is selected. In some embodiments, the porous
attachment layer material is selected, at least in part, based on
the porosity of the material.
[0083] In some embodiments, the porous attachment layer comprises a
hook material. The material used to form the hook material useful
in the abrasive article may be made in one of many different ways
known to those skilled in the art. Several suitable processes for
making hook material useful in making porous attachment layers
include, for example, methods described in U.S. Pat. Nos. 5,058,247
(Thomas et al.); 4,894,060 (Nestegard); 5,679,302 (Miller et al.);
and 6,579,161 (Chesley et al.).
[0084] The hook material may be a porous material such as, for
example the polymer netting material reported in U.S. Pat. Appln.
Publ. No. 2004/0170801 (Seth et al.). In other embodiments, the
hook material may be apertured to allow air to pass through.
Apertures may be formed in the hook material using any methods
known to those skilled in the art. For example, the apertures may
be cut from a sheet of hook material using, for example, a die,
laser, or other perforating instruments known to those skilled in
the art. In other embodiments, the hook material may be formed with
apertures.
[0085] The porous attachment layer of the abrasive article is
affixed to the filter medium in a manner that does not prevent the
flow of air from the filter medium. In some embodiments, the porous
attachment layer of the abrasive article is affixed to the filter
medium in a manner that does not substantially inhibit the flow of
air from the filter medium. The level of air flow through the
porous attachment layer may be restricted, at least in part, by the
introduction of an adhesive between a porous attachment layer
comprising a sheet material and the filter medium. The level of
restriction may be minimized by applying the adhesive between the
sheet material of the porous attachment layer and the filter medium
in a discontinuous fashion such as, for example, discrete adhesive
areas (e.g., atomized spray or starved extrusion die) or distinct
adhesive lines (e.g., hot melt swirl-spray or patterned roll
coater).
[0086] Exemplary useful adhesives include both pressure sensitive
and non-pressure sensitive adhesives. Pressure sensitive adhesives
are normally tacky at room temperature and may be adhered to a
surface by application of, at most, light finger pressure, while
non-pressure sensitive adhesives include solvent, heat, or
radiation activated adhesive systems. Examples of useful adhesives
include those based on general compositions of polyacrylate;
polyvinyl ether; diene-containing rubbers such as natural rubber,
polyisoprene, and polyisobutylene; polychloroprene; butyl rubber;
butadiene-acrylonitrile polymers; thermoplastic elastomers; block
copolymers such as styrene-isoprene and styrene-isoprene-styrene
block copolymers, ethylene-propylene-diene polymers, and
styrene-butadiene polymers; poly(alpha olefins); amorphous
polyolefins; silicone; ethylene-containing copolymers such as
poly(ethylene-co-vinyl acetate), poly(ethylene-co-ethyl acrylate),
and poly(ethylene-co-ethyl methacrylate); polyurethanes;
polyamides; polyesters; epoxies; poly(vinylpyrrolidone) and
vinylpyrrolidone copolymers; and mixtures of the above.
Additionally, the adhesives may contain additives such as
tackifiers, plasticizers, fillers, antioxidants, stabilizers,
pigments, diffusing particles, curatives, and solvents.
[0087] The various layers in the abrasive article may be held
together using any suitable form of attachment such as, for
example, glue, pressure sensitive adhesive, hot-melt adhesive,
spray adhesive, thermal bonding, needletacking, stitch bonding, and
ultrasonic bonding. In some embodiments, the layers are adhered to
one another by applying a spray adhesive such as, for example, "3M
BRAND SUPER 77 ADHESIVE", available from 3M Company, St. Paul,
Minn., to one side of the porous abrasive. In other embodiments, a
hot-melt adhesive is applied to one side of a layer using either a
hot-melt spray gun or an extruder with a comb-type shim. In yet
further embodiments, a preformed adhesive mesh is placed between
the layers to be joined.
[0088] If desired, a seal may be applied to the peripheral edge of
the abrasive article, typically to at least a majority (if not all)
of the peripheral edge, to reduce or prevent lateral escape of
particles not retained by the abrasive article. Examples of seals
include welds, tape, latex coatings, caulks, and sealants (e.g.,
latex or silicone).
[0089] Abrasive articles according to the present invention are
generally useful for collecting particles during abrading
processes, and in some cases, are capable of retaining large
amounts of particles at high rates of delivery. The abrasive
articles are suitable for use with any devices adapted for use with
such articles. Examples include random orbital, dual action, and
disc sanders, with or without vacuum applied to the porous
attachment layer and/or second nonwoven filter medium of the
abrasive article.
[0090] Although not wishing to be bound by any particular theory,
it is believed that in the case of abrasive articles according to
the present invention, the multiple filter components may function
such that a given component (e.g., the first nonwoven filter
medium) may be aided by a secondary component (e.g., the second
nonwoven filter medium) that may address the failure mode of the
first component and compensate, keeping overall efficiency high and
extending performance to a level that aligns with the performance
of the abrasive it is used with.
[0091] Accordingly, in some embodiments, at least a portion of an
abrasive article (e.g., representative of the perforated area)
according to the present invention (in an unused state) exhibits a
pressure drop according to the Pressure Drop Measurement Test
(hereinbelow) in a range of from 0.2 to 20 millimeters of water.
For example, at least a portion of an abrasive article according to
the present invention (in an unused state) may exhibits a pressure
drop according to the Pressure Drop Measurement Test in a range of
from 1 to 15 millimeters of water, or even 4 to 10 millimeters of
water.
[0092] The Pressure Drop Measurement Test is performed as
follows:
[0093] Pressure drop across the thickness of an abrasive article is
determined using a filter testing apparatus comprising a pair of
equal inside diameter cylinders mounted in series, such that, the
length of the cylinders is in the vertical direction, and such that
air flows through the cylinders with a face velocity of 5.2
centimeters per second. A pressure transducer is mounted to each
cylinder to measure the pressure within the cylinders. The adjacent
ends of the top and bottom cylinders are sealed upon the abrasive
article. The abrasive article being tested is tightly clamped, so
as to prevent sideways leakage, between the cylinders with the
outer abrasive surface of the abrasive article being perpendicular
to the direction of, and facing, the air flow. The difference in
air pressure between the first and second cylinders is recorded as
the pressure drop of the abrasive article.
[0094] All patents, patent applications, and publications cited
herein are each incorporated by reference in their entirety, as if
individually incorporated.
[0095] Advantages and other embodiments of this invention are
further illustrated by the following examples, but the particular
materials and amounts thereof recited in these examples, as well as
other conditions and details, should not be construed to unduly
limit this invention.
[0096] Unless otherwise indicated, all parts, percentages, ratios,
etc. in the Examples and the rest of the specification are by
weight.
EXAMPLES
[0097] The following abbreviations are used throughout the Examples
below:
TABLE-US-00001 MATERIALS IDENTIFICATION DESCRIPTION AM1 A
non-porous coated abrasive material, commercially available under
the trade designation "360L GRADE P800" from 3M Company; St. Paul,
Minnesota. AM2 AM1 laminated to a 13 mil transfer tape, the layered
construction laser cut to 5-inch (12.7-cm) diameter discs having a
distribution of laser perforated holes prepared according to
Procedure 2 (hereinbelow) AM3 A 6-inch (15.2-cm) diameter porous
coated abrasive material, commercially available under the trade
designation "NORTON MULTI-AIR, P800" from Norton, Worcester,
Massachusetts, die cut to a 5-inch (12.7-cm) diameter disc. AM4 A
grade P320 porous screen abrasive with an integral loop attachment
backing, commercially available under the trade designation
"ABRANET P320"from KWH Mirka Ltd., Jeppo, Finland. AM5 An ANSI
Grade 500 porous abrasive article, commercially available under the
trade designation "3M 281 FABRICUT" from the 3M Company, die cut
into 5-inch (12.7-cm) diameter discs. AM6 A replicate of the screen
abrasive described in Example 3 from U.S. Pat. Appl. Publ. No.
2006/0148390 A1 (Woo et al.) FM1 A nonwoven polyester pad,
commercially available under the trade designation "3M CARPET
BONNET PAD WHITE" from 3M Company, die cut to a 5-inch (12.7-cm)
diameter disc. FM2 An electret staple fiber web, 150 grams per
square meter basis weight, commercially available under the trade
designation "FILTRETE G150" from 3M Company, die cut to a 5-inch
(12.7-cm) diameter disc. FM3 FM1 having the edge sealed with a
commercially available caulk, as described in Procedure 1
(hereinbelow). FM4 A nonwoven filter medium prepared as described
in Procedure 6 (hereinbelow). FM5 A bimodal blown micro-fiber (BMF)
electret polypropylene web, 260 g/m.sup.2 basis weight, having a
thickness of 3.6 mm, prepared generally according to the procedure
of Example 1 of U.S. Pat. Appln. No. 11/461136 to Brandner et al.,
filed Jul. 31, 2006. FM6 A bimodal blown micro-fiber (BMF) electret
polypropylene web, 94 g/m.sup.2 basis weight, having a thickness of
0.9 mm, prepared generally according to the procedure of Example 1
of U.S. Pat. Appln. No. 11/461136 to Brandner et al., filed Jul.
31, 2006. AT1 A loop attachment fabric, commercially available
under the trade designation "70 G/M.sup.2 TRICOT DAYTONA BRUSHED
NYLON LOOP FABRIC" from Sitip SpA, Gene, Italy. FIB1 A polyester
staple fiber, commercially available under the trade designation
"T-240 COPET/PET" from Fiber Innovation Technology Inc. Johnson
City, Tennessee. FIB2 A polyester staple fiber, commercially
available under the trade designation "Type 224", 15 Denier, 2.0
inch length available from KoSa, Salisbury, North Carolina.
Procedure 1: Filter Medium Edge Sealing
[0098] The edge of a disc of filter medium 1, FM1, was sealed by
applying a smooth, continuous bead of silicon-acrylic caulking
material having the trade designation "DAP ALEX PLUS" manufactured
by DAP Products, Inc., Baltimore, Md.; around the peripheral edge
(abutting the circumference) of the disc. The caulk was forced into
the edge of the filter medium via a spatula. The caulk was allowed
to dry at least 8 hours. FM1, sealed in this manner was designated
as FM3.
Procedure 2: Lamination of Transfer Tape to Abrasive Material and
Laser Perforation
[0099] A sheet of abrasive material 1, AM1, was laminated to
similar sized sheet of a dual-sided transfer tape having the trade
designation "3M 964 13 MIL TRANSFER TAPE" available from the 3M
Company, by the following procedure. One side of the tape's liner
was removed and the side of a sheet of AM1 opposite the outer
abrasive surface was hand-laminated to the exposed, tacky pressure
sensitive adhesive of the tape. The laminated abrasive was laser
perforated according to pattern 400 shown in FIG. 4. Laser
perforated and cut 5-inch diameter discs of this layered
construction were designated as AM2.
Procedure 3: Attachment of Filter Medium or Abrasive Material to
AT1
[0100] A pressure-sensitive adhesive, commercially available under
the trade designation "SUPER 77 SPRAY ADHESIVE" from 3M Company,
was applied to the non-loop side of an approximately 6-inch
(15.2-cm) square sheet of AT1 and allowed to dry for approximately
30 seconds at 25 degrees Celsius. The dry weight of adhesive was
about 12 milligrams per square centimeter (mg/cm.sup.2). The
circular surface of the filter medium FM1, FM2, or FM3, or abrasive
material AM5 or AM6, was laminated to the adhesive coated surface
of AT1. The excess material of AT1 protruding from the edge of the
construction was removed by cutting with a scissors, creating a
circular, substantially coextensive, multi-layer construction.
Procedure 4: Attachment of Filter Medium to AM2
[0101] The liner of the transfer tape of AM2 was removed exposing
the tacky, pressure sensitive adhesive of the tape. The appropriate
circular disc of filter medium, FM1 or FM3, was aligned with and
hand laminated to the adhesive, such that, the layer of AM2 and the
layer of filter medium were substantially coextensive.
[0102] In some instances, FM1 and FM3 had previously been laminated
to a disc of FM2, as reported below. In those cases, the exposed
circular surface of FM1 or FM3, i.e., the side opposite the surface
attached to FM2, was laminated to AM2.
[0103] In the case were AM2 is attached to the FM4/FM5 needle
tacked filter medium, AM2 is attached to the exposed circular
surface of FM4, forming a substantially coextensive layers.
Procedure 5: Attachment of FM1 or FM3 to FM2
[0104] A pressure-sensitive adhesive, commercially available under
the trade designation "SUPER 77 SPRAY ADHESIVE" from 3M Company,
was applied to a circular surface of filter medium, FM1 or FM3, and
to a circular surface of FM2, and allowed to dry for approximately
30 seconds at 25 degrees Celsius. The dry weight of adhesive was
about 12 milligrams per square centimeter (mg/cm.sup.2). The two
adhesive coated, circular surfaces were then aligned and laminated
to one another. The construction was allowed to dry, creating a
substantially coextensive, two-layer construction.
Procedure 6: Fabrication of FM4
[0105] FM4 was formed from a 90/10, by weight, blend of FIB1 and
FIB2. The basis weight of the blend was about 155 grains/24 square
inch. (648 g/m.sup.2), with a thickness of about 5 inches (12 cm).
An air laid web former, trade designation "RANDO WEBBER", available
from Rando Machine Corporation, Macedon, N.Y. was employed using
conventional conditions to form FM4 from the indicated fiber
blend.
Procedure 7: Attachment of FM4 to FM5
[0106] Upon exit from the Rando Webber in Procedure 6, FM4 was
positioned above FM5 and the two layers were attached to one
another by passing them through a needle tacker, trade designation
"AUTOMATEX", available from STP Impianti Spa, Milan, Italy, at a
speed of 1.52 m/minute. The needle tacker rate was 185
strokes/minute, with a penetration from above of 15 mm, and a punch
density of 8.4 punches/cm.sup.2. Needles were type F20 9-37-9K
15.times.20.times.2.5, available from Foster Needle Co., Manitowoc,
Wis. The final basis weight for the needle tacked FM5/FM6 filter
medium was about 855 g/m.sup.2 with a thickness of about 5.2 mm.
The combined nonwoven structure was passed through a convection
oven for a period of 2 minutes at 129 degrees Celsius, where FIB1
bonded the entire structure together. The finished structure was
allowed to cool to 25 degrees Celsius.
[0107] Using the procedures described above, a variety of
multi-layer abrasive filter discs were prepared as designated in
Table 1, Table 2, and Table 3. Replicate examples (i.e., replicates
of the same construction) are designated by a numeral followed by a
letter (e.g., Example 1a, Example 1b, and Example 1c). Replicate
comparative examples are designated by a letter followed by a
numeral (e.g., Comparative Example A1, Comparative Example A2, and
Comparative Example A3). Various properties of some of the medium
materials are reported in Table 4.
[0108] For any given specific example, the components (e.g., porous
abrasive member, filter medium, and porous attachment layer) that
are adjacent to one another in the Tables are adjacent to one
another in the actual abrasive articles. It will be apparent to one
of skill in the art that the processing sequence in which the
layers are combined together to form the multi-layer abrasive disc
is often not of particular concern, as long as the desired final
construction is obtained.
[0109] Moreover, it will be realized that when two or more
differing filter medium materials are used in the construction of a
multi-layer abrasive filter disc, the order in which the filters
are placed relative to the abrasive medium may affect the
performance of the abrasive article. In this regard, differing
filter medium may not be interchangeable within the multilayer
construction. This includes the situation where a single filter
medium is employed that contains a gradient in its filtering
capabilities (e.g., it is substantially non-homogeneous in the
direction through which particles to be filtered flow).
Test Methods
Sanding Test Method 1
[0110] A 5.0-inch (12.7-cm) diameter abrasive disc was weighed and
then attached to a 40-hole, 5.0-inch (12.7-cm) diameter by 3/8-inch
(0.95-cm) thick foam back up pad, available under the trade
designation "3M HOOKIT BACKUP PAD, #20206" from 3M Company. The
backup pad and disc assembly was then mounted onto a 5-inch
(12.7-cm) diameter, medium finishing, dual-action orbital sander,
model 21033, obtained from Dynabrade Corp., Clarence, N.Y. The
abrasive face of the disc was manually brought into contact with a
pre-weighed, 18 inches by 30 inches (46 cm by 76 cm) gel-coated
fiberglass reinforced plastic panel, obtained from White Bear Boat
Works, White Bear Lake, Minn. The sander was run at 90 psi (620
kPa) air line pressure and a down force of 10 pounds force (44 N)
for 2 cycles of 75 seconds each. An angle of zero degrees to the
surface of the workpiece was used. Each cycle consisted of 24
overlapping transverse passes, for a combined 504 inches (12.8
meters) total length, at a tool speed of 6.7 inches per second (17
cm per second) across the panel surface resulting in an evenly
sanded area of test panel. After the first sanding cycle, the test
panel was cleaned by blowing compressed air across the top of the
sanded panel to remove visible dust. The disc was removed from the
back up pad and both the panel and disc were weighed. The abrasive
was remounted on the back up pad and the 75-second sanding cycle
was repeated using the same test panel. The test panel was again
cleaned by blowing compressed air across the top of the sanded
panel to remove visible dust. The abrasive disc was removed from
the back-up pad and both the panel and abrasive disc were weighed.
Reported data is after the 2.sup.nd sanding cycle, cumulative
sanding time of 150 seconds.
[0111] The following measurements were made for each sample tested
by this method and reported as an average of two test samples per
example in Tables 1 and Table 2 as indicated:
[0112] "Cut": Weight, in grams, removed from the plastic panel;
[0113] "Retain": weight, in grams, of particles collected in the
sample disc; and
[0114] "DE %": Ratio of the Retain/Cut multiplied by 100.
Sanding Test Method 2
[0115] A 5.0-inch (12.7-cm) abrasive filter disc was weighed,
attached to the back up pad and the disc/pad assembly was then
mounted to the orbital sander as described in Sanding Test Method
1. The abrasive face of the disc was manually brought into contact
with a pre-weighed, 18 inches by 30 inches (45.7 cm by 76.2 cm)
gel-coated fiberglass reinforced plastic panel obtained from White
Bear Boat Works, White Bear Lake, Minn. The sander was run at 90
psi (620 kPa) air line pressure for 6 cycles of 25 seconds each. An
angle of zero degrees to the surface of the workpiece was used.
After the first 3 cycles, the test panel was cleaned by blowing
compressed air across the top of the sanded panel to remove visible
dust. The disc was removed from the back up pad and both the panel
and disc were weighed. The abrasive was remounted on the back up
pad and the final 3 sanding cycles were conducted using the same
test panel. The test panel was again cleaned by blowing compressed
air across the top of the sanded panel to remove visible dust. The
abrasive disc was removed from the back up pad and both the panel
and abrasive disc were weighed. Reported data is after the 6.sup.th
sanding cycle, cumulative sanding time of 150 seconds.
[0116] The following measurements were made for each sample tested
by this method and reported as an average of two test samples per
example in Tables 1 and Table 2 as indicated:
[0117] "Cut": Weight, in grams, removed from the plastic panel;
[0118] "Retain": weight, in grams, of particles collected in the
sample disc; and
[0119] "DE %": Ratio of the Retain/Cut multiplied by 100.
Surface Finish Measurement Test Method
[0120] The resulting surface roughness of the abraded test panels
was determined by using a surface finish testing device available
under the trade designation "PERTHOMETER MODEL M4P-130589" from
Mahr Corporation, Cincinnati, Ohio. Surface finish values were
measured at three abraded sections of the test panel after each
completed 150-second sanding test. The Rz (also known as Rtm),
which is the mean of the maximum peak-to-valley values, was
recorded for each measurement.
Modified Pressure Drop Measurement Test
[0121] The Pressure Drop Measurement Test given herein above was
carried out using a filter testing apparatus comprising a pair of
4.5-inch (11.4-cm) inside diameter cylinders with an air flow rate
of 32 liters per minute. Pressure transducers were obtained from
MKS Instruments, Wilmington, Mass. under the trade designation "MKS
BARATRON PRESSURE TRANSDUCER, 398HD-00010SP12" (10 torr (1.33 kPa)
range).
[0122] Sanding Test 1 was used as the abrading procedure
corresponding to the data generated in Table 1. Sanding Test 2 was
used as the abrading procedure corresponding to the data generated
in Table 2.
[0123] Modified Pressure Drop Test measurements were not made on
all examples. Modified Pressure Drop Test for certain Examples
reported in Tables 1 and 2 are reported in Table 3 along with data
associated with additional comparative examples.
[0124] Modified Pressure Drop Test measurement were taken on
abrasive articles prior to any abrading conducted via Sanding Test
Method 1 or Sanding Test Method 2, with exceptions noted in Table
3.
TABLE-US-00002 TABLE 1 FIRST SECOND POROUS ABRASIVE FILTER FILTER
ATTACHMENT Cut, Retain, DE, Rz, MEMBER MEDIUM MEDIUM LAYER grams
grams percent micrometers Example 1a AM2 FM1 FM2 none 2.44 1.81 74
1.2 Example 2a AM2 FM3 FM2 none 2.30 1.49 65 1.4 Example 3a AM2 FM1
FM2 AT1 2.41 1.89 78 1.3 Example 4a AM2 FM3 FM2 AT1 2.49 1.86 75
1.4 Example 5 AM2 FM4 FM5 none 2.42 2.34 97 1.4 Comparative AM3
none none none 4.38 0.09 2 1.9 Example A1 Comparative AM3 none none
none 3.70 0.79 21 1.9 Example A4
TABLE-US-00003 TABLE 2 FIRST SECOND POROUS ABRASIVE FILTER FILTER
ATTACHMENT Cut, Retain, DE, Rz, MEMBER MEDIUM MEDIUM LAYER grams
grams percent micrometers Example 1b AM2 FM1 FM2 none 2.95 2.71 92
1.5 Example 2b AM2 FM3 FM2 none 3.24 2.97 92 1.3 Example 3b AM2 FM1
FM2 AT1 3.04 2.83 93 1.5 Example 4b AM2 FM3 FM2 AT1 2.79 2.58 92
1.5 Example 6 AM2 FM1 FM6 AT1 5.64 4.38 78 1.6 Example 7 AM2 FM3
FM6 AT1 4.51 3.86 86 1.7 Comparative AM3 none none none 3.57 0.07 2
2.1 Example A2 Comparative AM3 none none none 6.80 0.07 1 2.2
Example A3
[0125] Examples 1b, 2b, 3b, 4b and Comparative Example A2 were all
run using the same gel-coated fiberglass reinforced plastic panel.
Examples 6, 7 and Comparative Example A3 were all run using the
same gel-coated fiberglass reinforced plastic panel, yet a
different panel from the previous examples and comparative example.
Example 5 and Comparative Example A4 were run on yet another panel.
Variability in the panel can lead to variability in the measured
cut.
TABLE-US-00004 TABLE 3 POROUS FIRST SECOND ATTACH- .DELTA.P
ABRASIVE FILTER FILTER MENT (MM MEMBER MEDIUM MEDIUM LAYER
H.sub.2O) Example 1c AM2 FM1 FM2 none 1.25 Example 3c AM2 FM3 FM2
AT1 1.72 Example 1b* AM2 FM1 FM2 none 5.00 Example 3b* AM2 FM1 FM2
AT1 9.13 Example 5 AM2 FM4 FM5 none 2.04 Example 6 AM2 FM1 FM6 AT1
2.09 Example 7 AM2 FM3 FM6 AT1 2.33 Comparative AM3 none none none
0.06 Example A3 Comparative AM4 none none none 0.03 Example B
Comparative AM5 none none none 0.03 Example C Comparative AM5 none
none AT1 0.09 Example D Comparative AM6 none none none 0.03 Example
E Comparative AM6 none none AT1 0.10 Example F Comparative AM2 FM1
none none 0.38 Example G Comparative AM2 FM1 none AT1 0.71 Example
H *Examples 1b and 3b in the Table 3 (above) were measured after
Sanding Test Method 2 was completed.
TABLE-US-00005 TABLE 4 BASIS WEIGHT, BULK FIBER grams per CALIPER,
DENSITY, DIAMETER, MEDIUM square meter centimeters g/cm.sup.3
micrometers FM1 482 0.706 0.068 30 (461 503) (0.67 0.74) FM2 150
0.25 0.060 12 .times. 12 to 12 .times. 25 FM5 260 0.36 0.072 29
average (bimodal) FM6 94 0.087 0.107 22 average (bimodal) AT1 70
0.045 0.156 not determined
[0126] Various modifications and alterations of this invention may
be made by those skilled in the art without departing from the
scope and spirit of this invention, and it should be understood
that this invention is not to be unduly limited to the illustrative
embodiments set forth herein.
* * * * *