U.S. patent application number 16/420314 was filed with the patent office on 2019-09-26 for abrasive article and method of using the same.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Daniel E. Bygd, Nataliya V. Fedorova, Juan A. Munoz, Edward J. Woo, Jacob M. Zwier.
Application Number | 20190291242 16/420314 |
Document ID | / |
Family ID | 53800534 |
Filed Date | 2019-09-26 |
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United States Patent
Application |
20190291242 |
Kind Code |
A1 |
Zwier; Jacob M. ; et
al. |
September 26, 2019 |
ABRASIVE ARTICLE AND METHOD OF USING THE SAME
Abstract
An abrasive article having first and second major surfaces
includes a lofty open nonwoven fiber web comprising entangled
fibers. The fiber web includes a densified outer layer comprising a
portion of nonwoven fiber web proximate to the first major surface.
At least a portion the entangled fibers in the densified outer
layer are melt-bonded to one another. An abrasive material is
coated on the densified outer layer. The abrasive material includes
abrasive particles having a median particle diameter D50 in the
range of 1 to 15 microns retained in a binder material. The
abrasive article has a Stiffness Test force of 0.1 to 5.0 pounds
(0.45 to 2.27 kg) or less. The abrasive article can be used to
abrade a workpiece.
Inventors: |
Zwier; Jacob M.; (River
Falls, WI) ; Woo; Edward J.; (Woodbury, MN) ;
Fedorova; Nataliya V.; (Woodbury, MN) ; Bygd; Daniel
E.; (New Richmond, WI) ; Munoz; Juan A.;
(Blaine, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
53800534 |
Appl. No.: |
16/420314 |
Filed: |
May 23, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15118278 |
Aug 11, 2016 |
10343260 |
|
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PCT/US2015/014108 |
Feb 2, 2015 |
|
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16420314 |
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61939819 |
Feb 14, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24D 11/02 20130101;
B24D 11/00 20130101; B24D 3/28 20130101; B24D 3/002 20130101 |
International
Class: |
B24D 3/28 20060101
B24D003/28; B24D 11/00 20060101 B24D011/00 |
Claims
1. An abrasive article comprising: a single, non-laminated layer of
a nonwoven fiber web, the nonwoven fiber web comprising entangled
fibers; an abrasive material coated on the non-laminated layer of
nonwoven fiber web; and wherein the abrasive article has a void
volume of at least 75%.
2. The abrasive article of claim 1, wherein the abrasive article
has a void volume of at least 95%.
3. The abrasive article of claim 1, wherein the non-laminated layer
of nonwoven fiber web has a first surface opposed to a second
surface, and wherein the non-laminated layer of nonwoven fiber web
has a densified region proximate one or both of the first and
second surfaces.
4. The abrasive article of claim 3, wherein the densified region is
formed by a mechanical operation.
5. The abrasive article of claim 3, wherein the densified region is
formed by melt-bonding at least a portion of the entangled fibers
to one another.
6. The abrasive article of claim 1, wherein the abrasive material
comprises abrasive particles retained in a binder material.
7. The abrasive article of claim 6, wherein the abrasive material
is coated on a first surface of the non-laminated layer of nonwoven
fiber web, and wherein a second surface of the non-laminated layer
of nonwoven fiber web is substantially free of abrasive
particles.
8. The abrasive article of claim 6, wherein the abrasive particles
have a median particle diameter in the range of 1 to 15
microns.
9. The abrasive article of claim 8, wherein the abrasive particles
have a median particle diameter in the range of 2-12 microns.
10. The abrasive article of claim 9, wherein the abrasive particles
have a median particle diameter in the range of 4-10 microns.
11. A method of manufacturing a non-laminated abrasive article, the
method comprising: densifying a region of a nonwoven fiber web;
applying an abrasive precursor material to the densified nonwoven
fiber web; curing the abrasive precursor material; and wherein the
resulting abrasive article has a Stiffness Test Force between about
1.0 to about 5.0 pounds.
12. The method of claim 11, wherein the abrasive article has a void
volume of at least 75%.
13. The method of claim 11, wherein densifying comprises either a
mechanical densifying step or a heating densifying step.
14. The method of claim 11, and further comprising applying a
pre-bond resin to the nonwoven fiber web.
15. The method of claim 11, wherein the abrasive precursor material
is applied as a continuous layer to the densified nonwoven fiber
web.
16. The method of claim 11, and further comprising applying the
nonwoven fiber web to a backing.
17. A method of abrading a surface, the method comprising:
frictionally contacting an abrasive article to a workpiece; moving
at least one of the workpiece and the abrasive article relative to
the other; and wherein the abrasive article comprises a stiff
non-woven fiber web with a plurality of abrasive particles, and
wherein the stiff non-woven abrasive article has a Stiffness Test
force of 0.1 to 5.0 pounds or less.
18. The method of claim 17, wherein the non-woven fiber web
comprises at least some melt-bondable fibers.
19. The method of claim 17, wherein the non-woven fiber web
comprises a densified region, and wherein the abrasive particles
are applied to the densified region.
20. The method of claim 17, wherein the abrasive article is
operated in combination with a power tool.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/118,278, filed Aug. 11, 2016, now allowed, which is a
national stage filing under 35 U.S.C. 371 of PCT/US2015/014108,
filed Feb. 2, 2015, which claims the benefit of U.S. Provisional
Patent Application No. 61/939,819, filed Feb. 14, 2014, the
disclosures of which are incorporated by reference in their
entirety herein.
TECHNICAL FIELD
[0002] The present disclosure broadly relates to abrasive articles
and methods of using them.
BACKGROUND
[0003] Consumers have come to expect a glossy, aesthetic exterior
finish on new vehicles, such as automobiles and boats. Similar
expectations also exist in the aftermarket industry, where vehicles
undergo repairs after the exterior of the vehicle has been damaged.
Yet achieving a truly aesthetic finish can be daunting. The human
eye is extremely keen in its ability to spot even the slightest
surface defects, which in turn degrade the finish. Manufacturers
and repair shops thus demand rigorous systems and methods capable
of removing substantially all surface defects to gain customer
acceptance. These systems and methods generally require highly
specialized abrasive products used in combination with specialized
procedures in order to obtain aesthetically acceptable results.
[0004] For example, a typical automotive exterior repair job is a
multi-step process involving a series of abrasives having
progressively smaller and smaller grain sizes. In a typical
procedure, a portion of the panel of an automobile to be repaired
is first sanded using a coarse abrasive material that fully removes
any pre-existing paint from the metal surface. The surface is then
cleaned and coated with a suitable body repair material, such a
body filler, putty, epoxy resin, or urethane resin.
[0005] Once hardened, the repair material is sanded so that it is
flush with the surrounding surface using a progression of
abrasives. The sanded area is then coated with a primer layer,
typically using a spray gun. After the primer layer is dry, a
suitable abrasive is then used to sand the primed surface. The
primed surface is then cleaned, and, optionally, surrounding panels
are scuffed and a base coat applied with a color that generally
matches the rest of the vehicle. A transparent clear coat is then
applied over the entire surface of any panels to which base coat
was applied. An appropriate abrasive is then used to remove defects
such as dirt nibs, dust particles, or excessive orange peel
texture. A set of abrasives and/or polishing compounds are then
used to remove any sand scratches from the clear coat, and to
restore a glossy finish.
[0006] A number of foam-backed abrasive products and/or processes
are known and have been practiced in the art for achieving a high
gloss surface finish; for example, see U.S. Pat. No. 6,183,677
(Usui et al.); U.S. Pat. No. 6,406,504 (Lise et al.); U.S. Pat. No.
7,618,30 (Felipe et al.); and U.S. Pat. Appln. Publ. Nos.
2007/0066186 A1 (Annen et al.) and 2002/0090901 A1 (Schutz et
al.).
SUMMARY
[0007] The present inventors have unexpectedly discovered that,
contrary to general belief among those skilled in the art, a
nonwoven abrasive article construction can successfully achieve
high gloss finishes, thereby obviating the need for
expensive/complicated alternative constructions that are known and
used in the art.
[0008] Advantageously, abrasive articles according to the present
disclosure are capable of generating a similar surface finish to
foam products in the market today, and have the potential to be
manufactured at lower cost process than corresponding laminated
foam-backed abrasive products. Advantageously, abrasive articles
according to the present disclosure may exhibit a higher cut rate,
longer cut life, and similar surface finish to foam products in the
market today.
[0009] In one aspect, the present disclosure provides an abrasive
article having first and second major surfaces and comprising:
[0010] a lofty open nonwoven fiber web comprising entangled fibers,
wherein the lofty open nonwoven fiber web further comprises:
[0011] a densified outer layer comprising a portion of nonwoven
fiber web proximate to the first major surface, wherein at least a
portion the entangled fibers in the densified outer layer are
melt-bonded to one another; and
[0012] an abrasive material coated on the densified outer layer,
wherein the abrasive material comprises abrasive particles retained
in a binder material, and wherein the abrasive particles have a
median particle diameter D.sub.50 in the range of 1 to 15 microns,
and
[0013] wherein the abrasive article has a Stiffness Test force of
0.1 to 5.0 pounds (0.45 to 2.27 kg) or less.
[0014] In another aspect, the present disclosure provides a method
of buffing a workpiece, the method comprising:
[0015] frictionally contacting the first surface an abrasive
article according to the present disclosure with a workpiece;
and
[0016] moving at least one of the workpiece and the abrasive
article relative to the other to abrade at least a portion of
workpiece.
[0017] In some embodiments, the workpiece comprises a finish layer
disposed on a substrate.
[0018] Features and advantages of the present disclosure will be
further understood upon consideration of the detailed description
as well as the appended claims. Numerical ranges are to be
considered inclusive of their endpoints unless clearly indicated to
the contrary.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a schematic side view of an exemplary abrasive
article 100 according to one embodiment of the present
disclosure.
[0020] FIG. 1B is an enlarged view of region 1B in FIG. 1A.
[0021] FIG. 2A is a digital micrograph of heat-treated nonwoven
fiber web used in Example 2.
[0022] FIG. 2B is a digital micrograph of the abrasive article made
in Example 2.
[0023] FIG. 3A is a digital micrograph of heat-treated nonwoven
fiber web used in Comparative Example B.
[0024] FIG. 3B is a digital micrograph of the abrasive article made
in Comparative Example B.
[0025] FIG. 4A is a digital micrograph of non-heat-treated nonwoven
fiber web used in Comparative Example D.
[0026] FIG. 4B is a digital micrograph of the abrasive article made
in Comparative Example D.
[0027] FIG. 5A is a scale schematic perspective view of Testing
Fixture A used in the Stiffness Test hereinbelow.
[0028] FIG. 5B is a scale schematic partial cross-sectional side
view of Testing Fixture A used in the Stiffness Test
hereinbelow.
[0029] It should be understood that numerous other modifications
and embodiments can be devised by those skilled in the art, which
fall within the scope and spirit of the principles of the
disclosure.
DETAILED DESCRIPTION
[0030] Referring now to FIGS. 1A and 1B, abrasive article 100 has
first and second opposed major surfaces (112, 114) and comprises
lofty open nonwoven fiber web 110. Lofty open nonwoven fiber web
110 comprises entangled fibers 102 and a densified outer layer 116
(i.e., densified relative to the interior of the lofty open fiber
web) proximate to first major surface 112. At least a portion of
entangled fibers 102 within the densified outer layer 116 are
melt-bonded to one another at bonding points 117. Abrasive material
120 is coated on densified outer layer 116. Abrasive material 120
comprises abrasive particles 130 retained in binder material 140.
Abrasive particles 130 have a median particle diameter D.sub.50 in
the range of from 1 to 15 microns. Abrasive article 100 has a
Stiffness Test (described hereinbelow) force (i.e., the maximum
force required to force the test fabric through the opening in the
test fixture) of 0.1 to 5.0 pounds (0.45 to 2.27 kg).
[0031] Suitable lofty open nonwoven fiber webs (hereinafter, the
"nonwoven fiber webs") that are suitable for use in the
aforementioned abrasive articles are well known in the abrasives
art. Fibers used in the manufacture of the nonwoven fiber web are
typically selected to be suitably compatible with adhering binders
and abrasive particles while also being processable in combination
with other components of the abrasive article, and typically can
withstand processing conditions (e.g., temperatures) such as those
employed during application and curing of the abrasive material
precursor. The fibers may be chosen to affect properties of the
abrasive article such as, for example, flexibility, elasticity,
durability or longevity, abrasiveness, and finishing properties.
Examples of fibers that may be suitable include natural fibers,
synthetic fibers, and mixtures of natural and/or synthetic
fibers.
[0032] Examples of useful synthetic fibers include those made from
polyester (e.g., polyethylene terephthalate), nylon (e.g.,
hexamethylene adipamide, or polycaprolactam), polypropylene,
acrylonitrile (i.e., acrylic), rayon, cellulose acetate,
polyvinylidene chloride-vinyl chloride copolymers, and vinyl
chloride-acrylonitrile copolymers. Examples of suitable natural
fibers include cotton, wool, jute, and hemp. The fiber may be of
virgin material or of recycled or waste material, for example,
reclaimed from garment cuttings, carpet manufacturing, fiber
manufacturing, or textile processing. The fiber may be homogenous
or a composite such as a bicomponent fiber (e.g., a co-spun
sheath-core fiber). The fibers may be tensilized and/or crimped.
Combinations of such fibers may also be used. The fibers can be
used in the form of a web, a batt, or a tow. As used herein, a
"batt" refers to a plurality of air laid webs or similar
structures.
[0033] An important consideration in the selection of the fiber is
that it does not melt or decompose at temperatures at or below the
melting or curing temperature of the adhesive used as the fiber and
abrasive bonding agent. The fiber used may be virgin fibers or
waste fibers reclaimed from garment cuttings, carpet manufacturing,
fiber manufacturing, or textile processing, and so forth. The fiber
material can be a homogenous fiber or a composite fiber, such as
bicomponent fiber (e.g., a co-spun sheath-core fiber). Generally,
at least some of the fibers should be selected such that they can
be softened or melted sufficiently that bonding can occur between
fibers at points where they contact one another, especially in the
densified region of the nonwoven fiber web.
[0034] The fibers may comprise continuous fiber, staple fiber, or a
combination thereof. For example, the fiber web may comprise staple
fibers having a length of at least about 20 millimeters (mm), at
least about 30 mm, or at least about 40 mm, and less than about 110
mm, less than about 85 mm, or less than about 65 mm, although
shorter and longer fibers (e.g., continuous filaments) may also be
useful.
[0035] The fineness or linear density of the fiber used may vary
widely, depending upon the results desired. Preferred fine fibers
include those having a linear density from about 1 to 25 denier
(1.1 to 27.8 dtex), more preferably 4 to 16 denier (4.4 to 17.8
dtex), although finer or coarser fibers may be used depending, for
example, on the application envisaged for the finished abrasive
article. Preferred coarse fibers include those having a linear
density of about 40 to bout 60 denier (4.4 to 70 dtex). Mixtures of
fibers (e.g., coarse and fine fibers) with differing linear
densities may be useful, for example, to provide an abrasive
article that upon use will result in a specifically preferred
surface finish. Those skilled in the art will understand that the
present disclosure is not limited by the nature of the fibers
employed or by their respective lengths, denier, and the like.
[0036] The nonwoven fiber web may be made, for example, by
conventional air-laid and/or carded, stitch-bonded, spun-bonded,
and/or melt blown procedures. Air-laid fiber webs may be prepared
using equipment such as, for example, that available under the
trade designation RANDO WEBBER from Rando Machine Company of
Macedon, N.Y. With such processing equipment, fiber length
ordinarily should be maintained within about 1.25 cm to about 10
cm. However, with other types of conventional web forming
equipment, fibers of different length, or combinations thereof also
can be utilized to form the nonwoven fiber webs. The thickness of
the fibers is not particularly limited (apart from processing
considerations), as long as due regard is given to the resilience
and toughness ultimately desired in the resulting web. With the
RANDO-WEBBER equipment, fiber thickness is preferably within a
range of about 25 to about 250 micrometers. However, in the
interest of obtaining a three-dimensional structure with maximum
loft and openness, it is preferable that all or a substantial
amount of the fibers be crimped. It will be appreciated that
crimping may be unnecessary where the fibers readily interlace with
one another to form and retain a highly open lofty relationship in
the formed web.
[0037] It is also contemplated that the nonwoven fiber web may
comprise an opened tow of substantially parallel-arranged filaments
as the nonwoven flexible abrasive article. In this embodiment, a
nonwoven abrasive pad, for example, can be formed by coating an
opened tow of filaments with adhesive before or while depositing an
abrasive material precursor on the tow.
[0038] The nonwoven fiber web is preferably reinforced, for
example, using a prebond resin (e.g., a phenolic, urethane, or
acrylic resin), by including core-sheath melty fibers, and/or by
mechanical entanglement (e.g., hydroentanglement, or needletacking)
using methods well-known in the art. Such reinforcement can be
imparted to the web, preferably as a separate treatment before the
abrasive material is secured to the nonwoven fiber web. A curable
prebond resin, which is generally devoid of abrasive components,
may be used to reinforce the nonwoven fiber web.
[0039] The prebond resin serves, for example, to help maintain the
nonwoven fiber web integrity during handling, and may also
facilitate bonding of the urethane binder to the nonwoven fiber
web. Examples of prebond resins include phenolic resins, urethane
resins, hide glue, acrylic resins, urea-formaldehyde resins,
melamine-formaldehyde resins, epoxy resins, and combinations
thereof. The amount of prebond resin used in this manner is
typically adjusted toward the minimum amount consistent with
bonding the fibers together at their points of crossing contact. In
those cases, wherein the nonwoven fiber web includes thermally
bondable fibers, thermal bonding of the nonwoven fiber web may also
be helpful to maintain web integrity during processing. Various
other optional conventional treatments and additives may be used in
conjunction with the nonwoven fiber web such as, for example,
application of antistatic agents, lubricants, or corona
treatment.
[0040] The curable prebond resin is generally applied to the fibers
of the nonwoven fiber web as a liquid coating using known coating
or spraying techniques followed by curing/hardening of the prebond
resin (e.g., by heat curing), thereby bonding the fibers of the web
to one another at their mutual contact points. Suitable adhesive
materials that can be used in this regard are known and include
those described in U.S. Pat. No. 2,958,593 (Hoover et al.). Where
melt-bondable fibers are included within the construction of the
nonwoven fiber web, the fibers may be adhered to one another at
their mutual contact points by an appropriate heat treatment of the
web to melt at least one of the components of the fiber. The melted
component performs the function of an adhesive so that, upon
cooling, the melted component will re-solidify and thereby form
bonds at the mutual contact points of the fibers of the web. The
inclusion of melt-bondable fibers (such as those described in U.S.
Pat. No. 5,082,720 (Hayes)) in a nonwoven fiber web may or may not
be accompanied by the application of a prebond resin, as known by
those skilled in the art. The selection and use of melt-bondable
fibers, the selection and application of a prebond resin and the
conditions required for bonding the fibers of a nonwoven to one
another (e.g., by melt-bonding or by prebond resin) are typically
within the skill of those practicing in the field.
[0041] As mentioned above, the fibers may be bonded together at
their mutual contact points (at least in the densified region) to
provide the nonwoven fiber web where the interstices between fibers
are left substantially unfilled by resin or abrasive. For typical
applications, the void volume of the finished abrasive article
preferably is in the range of about 75 volume percent to about 95
volume percent. At lower void volumes, there may be a greater
tendency to clog-up which reduces the abrasion rate and hinders
cleaning of the nonwoven fiber web by flushing. If the void volume
is too high, the nonwoven fiber web may lack adequate structural
strength to withstand the stresses associated with cleaning or
scouring operations.
[0042] The nonwoven fiber web may optionally incorporate, or be
secured to, a scrim and/or backing (e.g., using glue or a hot-melt
adhesive or by needletacking), if desired, for additional
reinforcement.
[0043] Prior to coating with the abrasive material precursor, the
nonwoven fiber web preferably has a weight per unit area (i.e.,
basis weight) of about 20 grams per square meter (gsm) to about 100
gsm, preferably about 30 gsm to about 90 gsm, and more preferably
about 40 gsm to about 80 gsm, as measured prior to any coating
(e.g., with the curable composition or optional pre-bond resin),
although greater and lesser basis weights may also be used. In
addition, prior to coating with the abrasive material precursor,
the fiber web typically has a thickness of about 2 millimeters (mm)
to about 20 mm, preferably 3 mm to about 15 mm, more preferably
about 4 mm to about 9 mm, although greater and lesser thicknesses
may also be used.
[0044] At least one major surface of the nonwoven fiber web,
preferably only one major surface, or the nonwoven fiber web is
characterized by a densified region proximate one or both of its
two opposed major surfaces (e.g., top and bottom surfaces). In the
densified region, the fiber density is higher than in adjacent
inner regions of the nonwoven fiber web. The densified region(s)
can be formed by any suitable method, which will be known to those
of ordinary skill in the art. Examples of methods include
mechanical methods (for example, needletacking or hydroentanglement
and heating methods (e.g., using one or more of a heated calender
roll, hot can, heat gun, impingement oven, or radiant heater).
Preferably the heat treatment also is effective for smoothing the
surface of the nonwoven fiber web. Accordingly, in preferred
embodiments, the densified region(s) of the fiber web have a
smoother and/or flatter surface than is present in the nonwoven
fiber web before forming the densified region.
[0045] Further details concerning suitable fiber webs and methods
for their manufacture may be found, for example, in U.S. Pat. No.
6,207,246 (Moren et al.); U.S. Pat. No. 5,591,239 (Larson et al.);
U.S. Pat. No. 4,227,350 (Fitzer); and U.S. Pat. No. 2,958,593
(Hoover et al.).
[0046] As is described in more detail below, the abrasive material
is formed through deposition of an abrasive material precursor,
containing a binder material precursor material and abrasive
particles, onto the densified region of the nonwoven fiber web.
When cured, the binder material precursor material is converted
into the binder material, which provides sufficient adhesion to
strongly bond the abrasive particles to the fibers. The abrasive
material precursor is applied to the densified region of the
nonwoven fiber web, preferably solely to the densified region,
although this is not a requirement. The abrasive material precursor
is preferably applied as a continuous layer across the fibers at
the first major surface of the abrasive article, although the layer
may be discontinuous, if desired. Although the abrasive material
precursor layer is preferably continuous (as well as the resultant
abrasive material after curing), it will have openings therein
corresponding to regions without fibers.
[0047] The abrasive material is generally formed by curing the
binder material precursor component of an abrasive material
precursor after it is applied to the nonwoven fiber web, and
optionally at least partially dried.
[0048] Useful binder material precursors may comprise a monomeric
or polymeric material that may cured (e.g., polymerized and/or
crosslinked). Typically, upon curing, such binder material
precursors form a non-elastomeric binder material (e.g., a hard
brittle binder material) that bonds abrasive particles to the
nonwoven fiber web. The binder material may have a Knoop hardness
number (KHN, expressed in kilograms-force per millimeter (kgf/mm))
of, for example, at least about 20 kgf/mm, at least about 40
kgf/mm, at least about 60 kgf/mm, or at least about 80 kgf/mm.
[0049] Suitable binder material precursors may include
condensation-curable materials and/or addition-polymerizable
materials. Such binder material precursors may be solvent-based,
water-based, or 100 percent solids. Exemplary binder material
precursors include phenolic resins, bismaleimides, vinyl ethers,
aminoplasts, urethane prepolymers, epoxy resins, acrylates,
acrylated isocyanurates, urea-formaldehyde resins, isocyanurates,
acrylated urethanes, acrylated epoxies, or mixtures of any of the
foregoing. Phenolic resins and epoxy resins, and combinations
thereof, are among preferred binder material precursors due to
their high performance, wide availability, and low cost.
[0050] Exemplary phenolic resins suitable for use in binder
material precursors include resole phenolic resins and novolac
phenolic resins. Exemplary commercially available phenolic
materials include those having the trade designations "DUREZ" or
"VARCUM" (available from Durez Corporation, Novi, Mich.); "AROFENE"
or "AROTAP" (available from Ashland Chemical Company, Columbus,
Ohio); and "BAKELITE" (available from Momentive Specialty
Chemicals, Columbus, Ohio). Further details concerning suitable
phenolic resins may be found, for example, in U.S. Pat. No.
5,591,239 (Larson et al.) and U.S. Pat. No. 5,178,646 (Barber, Jr.
et al.).
[0051] Exemplary epoxy resins include the diglycidyl ether of
bisphenol A, as well as materials that are commercially available
under the trade designation "EPON" (e.g., EPON 828, EPON 1004, and
EPON 1001F) from Momentive Specialty Chemicals; and under the trade
designations "D.E.R." (e.g., D.E.R. 331, D.E.R. 332, and D.E.R.
334) or "D.E.N." (e.g., D.E.N. 431 and D.E.N. 428) from Dow
Chemical Company, Midland, Mich.
[0052] Exemplary urea-formaldehyde resins and melamine-formaldehyde
resins include those commercially available as UFORMITE from Cytec
Technology Corporation, Wilmington Del.; as DURITE from Momentive
Specialty Chemicals; and as RESIMENE from INEOS Melamines GmbH,
Frankfort, Germany.
[0053] Examples of useful urethane prepolymers include
polyisocyanates and blocked versions thereof. Typically, blocked
polyisocyanates are substantially unreactive to isocyanate reactive
compounds (e.g., amines, alcohols, thiols, etc.) under ambient
conditions (e.g., temperatures in a range of from about 20.degree.
C. to about 25.degree. C.), but upon application of sufficient
thermal energy the blocking agent is released, thereby generating
isocyanate functionality that reacts with the amine curative to
form a covalent bond.
[0054] Useful polyisocyanates include, for example, aliphatic
polyisocyanates (e.g., hexamethylene diisocyanate or
trimethylhexamethylene diisocyanate); alicyclic polyisocyanates
(e.g., hydrogenated xylylene diisocyanate or isophorone
diisocyanate); aromatic polyisocyanates (e.g., tolylene
diisocyanate or 4,4'-diphenylmethane diisocyanate); adducts of any
of the foregoing polyisocyanates with a polyhydric alcohol (e.g., a
diol, low molecular weight hydroxyl group-containing polyester
resin, and water); adducts of the foregoing polyisocyanates (e.g.,
isocyanurates, biurets); and mixtures thereof.
[0055] Useful commercially available polyisocyanates include, for
example, those available under the trade designations: "ADIPRENE"
from Chemtura Corporation, Middlebury, Conn. (e.g., ADIPRENE L
0311, ADIPRENE L 100, ADIPRENE L 167, ADIPRENE L 213, ADIPRENE L
315, ADIPRENE L 680, ADIPRENE LF 1800A, ADIPRENE LF 600D, ADIPRENE
LFP 1950A, ADIPRENE LFP 2950A, ADIPRENE LFP 590D, ADIPRENE LW 520,
and ADIPRENE PP 1095); "MONDUR" from Bayer Corporation, Pittsburgh,
Pa. (e.g., MONDUR 1437, MONDUR MP-095, or MONDUR 448); and
"AIRTHANE" and "VERSATHANE" from Air Products and Chemicals,
Allentown, Pa. (e.g., AIRTHANE APC-504, AIRTHANE PST-95A, AIRTHANE
PST-85A, AIRTHANE PET-91A, AIRTHANE PET-75D, VERSATHANE STE-95A,
VERSATHANE STE-P95, VERSATHANE STS-55, VERSATHANE SME-90A, and
VERSATHANE MS-90A).
[0056] To lengthen pot-life, polyisocyanates such as, for example,
those mentioned above may be blocked with a blocking agent
according to various techniques known in the art. Exemplary
blocking agents include ketoximes (e.g., 2-butanone oxime); lactams
(e.g., epsilon-caprolactam); malonic esters (e.g., dimethyl
malonate and diethyl malonate); pyrazoles (e.g.,
3,5-dimethylpyrazole); alcohols including tertiary alcohols (e.g.,
t-butanol or 2,2-dimethylpentanol), phenols (e.g., alkylated
phenols), and mixtures of alcohols as described.
[0057] Exemplary useful commercially-available blocked
polyisocyanates include those marketed by Chemtura Corporation as
ADIPRENE BL 11, ADIPRENE BL 16, and ADIPRENE BL 31, and blocked
polyisocyanates marketed by Baxenden Chemicals, Ltd., Accrington,
England under the trade designation "TRIXENE" (e.g., TRIXENE BL
7641, TRIXENE BL 7642, TRIXENE BL 7772, and TRIXENE BL 7774).
[0058] Typically, the amount of binder material precursor present
in the abrasive material precursor is from 10 to 40 percent by
weight, more typically in an amount of from 15 to 30 percent by
weight, and even more typically in an amount of from 20 to 25
percent by weight based on the total weight of the abrasive
material precursor, although amounts outside of these ranges may
also be used.
[0059] Suitable amine curatives for urethane prepolymers include
aromatic, alkyl-aromatic, or alkyl polyfunctional amines,
preferably primary amines. Examples of useful amine curatives
include 4,4'-methylenedianiline; polymeric methylene dianilines
having a functionality of 2.1 to 4.0 available as CURITHANE 103
from the Dow Chemical Company, and as MDA-85 from Bayer
Corporation; 1,5-diamine-2-methylpentane; tris(2-aminoethyl)amine;
3-aminomethyl-3,5,5-trimethylcyclohexylamine (i.e.,
isophoronediamine), trimethylene glycol di-p-aminobenzoate,
bis(o-aminophenylthio)ethane, 4,4'-methylenebis(dimethyl
anthranilate), bis(4-amino-3-ethylphenyl)methane (e.g., marketed as
KAYAHARD AA by Nippon Kayaku Company, Ltd., Tokyo, Japan), and
bis(4-amino-3,5-diethylphenyl)methane (e.g., marketed as LONZACURE
M-DEA by Lonza, Ltd., Basel, Switzerland); and mixtures thereof. If
desired, polyol(s) may be added to the curable composition, for
example, to modify (e.g., to retard) cure rates as required by the
intended use.
[0060] Optionally, but typically, the binder material precursor
further includes one or more catalysts and/or curing agents to
initiate and/or accelerate the curing process (e.g., thermal
catalyst, hardener, crosslinker, photocatalyst, thermal initiator,
and/or photoinitiator) as well as in addition, or alternatively,
other known additives such as fillers, thickeners, tougheners,
grinding aids, pigments, fibers, tackifiers, lubricants, wetting
agents, surfactants, antifoaming agents, dyes, coupling agents,
plasticizers, suspending agents, bactericides, fungicides, grinding
aids, and antistatic agents. The selection and amounts of
appropriate catalysts, curing agents, and other additives is within
the capability of one of ordinary skill in the art.
[0061] The binder material precursor may include at least one
organic solvent (e.g., isopropyl alcohol or methyl ethyl ketone) to
facilitate coating onto the nonwoven fiber web, although this is
not a requirement.
[0062] Exemplary lubricants include metal stearate salts such as
lithium stearate and zinc stearate, molybdenum disulfide, and
mixtures thereof.
[0063] As used herein, the term "grinding aid" refers to a
non-abrasive (e.g., having a Mohs hardness of less than 7)
particulate material that has a significant effect on the chemical
and physical processes of abrading. In general, the addition of a
grinding aid increases the useful life of a nonwoven abrasive.
Exemplary grinding aids include inorganic and organic materials,
include waxes, organic halides (e.g., chlorinated waxes, polyvinyl
chloride), halide salts (e.g., sodium chloride, potassium cryolite,
cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium
tetrafluoroborate, silicon fluorides, potassium chloride, magnesium
chloride), metals (e.g., tin, lead, bismuth, cobalt, antimony,
cadmium, iron, and titanium and their alloys), sulfur, organic
sulfur compounds, metallic sulfides, graphite, and mixtures
thereof.
[0064] Binder material precursors may typically be cured by
exposure to, for example, thermal energy (e.g., by direct heating,
induction heating, and/or by exposure to microwave and/or infrared
electromagnetic radiation) and/or actinic radiation (e.g.,
ultraviolet light, visible light, particulate radiation). Exemplary
sources of thermal energy include ovens, heated rolls, and infrared
lamps.
[0065] Suitable methods for applying binder material precursors
(whether alone or as a slurry in combination with abrasive
particles) are well known in the art of abrasive articles, and
include coating methods such as curtain coating, roll coating,
spray coating, and the like. Typically, spray coating is an
effective and economical method. Exemplary slurry coating
techniques are described, for example, in U.S. Pat. Nos. 5,378,251
and 5,942,015 (both to Culler et al.).
[0066] Abrasive particles suitable for use in abrasive compositions
utilized in practice according to the present disclosure include
any abrasive particles known in the abrasive art. Exemplary useful
abrasive particles include fused aluminum oxide based materials
such as aluminum oxide, ceramic aluminum oxide (which may include
one or more metal oxide modifiers and/or seeding or nucleating
agents), and heat-treated aluminum oxide, silicon carbide, co-fused
alumina-zirconia, diamond, ceria, titanium diboride, cubic boron
nitride, boron carbide, garnet, flint, emery, sol-gel derived
abrasive particles, and mixtures thereof. Desirably, the abrasive
particles comprise fused aluminum oxide, heat-treated aluminum
oxide, ceramic aluminum oxide, silicon carbide, alumina zirconia,
garnet, diamond, cubic boron nitride, sol-gel derived abrasive
particles, or mixtures thereof. Examples of sol-gel abrasive
particles include those described U.S. Pat. No. 4,314,827
(Leitheiser et al.); U.S. Pat. No. 4,518,397 (Leitheiser et al.);
U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No.
4,744,802 (Schwabel); U.S. Pat. No. 4,770,671 (Monroe et al.); U.S.
Pat. No. 4,881,951 (Wood et al.); U.S. Pat. No. 5,011,508 (Wald et
al.); U.S. Pat. No. 5,090,968 (Pellow); U.S. Pat. No. 5,139,978
(Wood); U.S. Pat. No. 5,201,916 (Berg et al.); U.S. Pat. No.
5,227,104 (Bauer); U.S. Pat. No. 5,366,523 (Rowenhorst et al.);
U.S. Pat. No. 5,429,647 (Larmie); U.S. Pat. No. 5,498,269 (Larmie);
and U.S. Pat. No. 5,551,963 (Larmie). The abrasive particles may be
in the form of, for example, individual particles, agglomerates,
composite particles, and mixtures thereof. Exemplary agglomerates
and composite particles are described, for example, in U.S. Pat.
No. 4,652,275 (Bloecher et al.); U.S. Pat. No. 4,799,939 (Bloecher
et al.); and U.S. Pat. No. 5,549,962 (Holmes et al.).
[0067] Useful abrasive particles a median particle diameter
D.sub.50 in the range of from 1 to 15 microns, preferably 2 to 12
microns, and more preferably 4 to 10 microns. As used herein, the
term D50 is used according to its ordinary meaning in the art and
refers to the median particle diameter of a distribution of the
particles. Methods of determining D.sub.50 are well known and may
include that described in ASTM test method E2651-13, "Standard
Guide for Powder Particle Size Analysis".
[0068] Preferably, the abrasive particles conform to an abrasives
industry specified nominal grade, although this is not a
requirement. Such abrasives industry accepted grading standards
include those known as the American National Standards Institute,
Inc. (ANSI) standards, Federation of European Producers of Abrasive
Products (FEPA) standards, and Japanese Industrial Standard (JIS)
standards. Exemplary suitable ANSI grade designations (i.e.,
specified nominal grades) include ANSI 600, ANSI 800, ANSI 1000,
and ANSI 1200. Exemplary suitable FEPA grade designations include
FEPA 500, FEPA 600, FEPA 800, FEPA 1000, and FEPA 1200. Exemplary
suitable JIS grade designations include JIS 800, JIS 1000, JIS
1500, JIS 2500, JIS 3000, JIS 4000, and JIS 6000.
[0069] Useful abrasive particles may also include shaped ceramic
abrasive particles as described in U.S. Pat. No. 8,142,532
(Erickson et al.); U.S. Pat. No. 8,142,531 (Adefris et al.); U.S.
Pat. No. 8,123,828 (Culler et al.); and U.S. Pat. No. 8,034,137
(Erickson et al.), and crushed versions thereof.
[0070] Typically, the coating weight for the abrasive particles
(independent of other ingredients in the curable composition) may
depend, for example, on the particular binder material precursor
used, the process for applying the abrasive particles, and the size
of the abrasive particles. For example, the weight of the abrasive
particles on the nonwoven fiber web may be from about 10 grams per
square meter (gsm) to about 80 gsm, preferably from about 20 gsm to
about 60 gsm, and more preferably from 30 to 60 gsm, although other
amounts may also be used.
[0071] Abrasive articles (e.g., webs and sheets) according to the
present disclosure may be manufactured through processes that
include common steps. In one preferred method, an abrasive material
precursor comprising a binder material precursor material and
abrasive particles is deposited onto the nonwoven fiber web, for
example, by spraying or roll coating the abrasive material
precursor as a slurry. In an alternative method, the binder
material precursor material is coated on the nonwoven fiber web,
and then abrasive particles are deposited on the binder material
precursor material prior to curing.
[0072] As an alternative to application as slurry with binder
material precursor, abrasive particles may be applied to a nonwoven
fiber web having a binder material precursor coated thereon using
methods known in the abrasive art for application of such
particles. For example, the abrasive particles may be applied by
blowing or dropping the particles onto uncured binder material
precursor, or by a combination thereof. The abrasive material
precursor is preferably applied to the nonwoven fiber web to
provide (after drying and curing) an abrasive material add-on
weight within the range from about 1 gsm to about 50 gsm,
preferably from about 4 gsm to about 25 gsm, although other amounts
may also be used. However, the specific add-on weights will depend
on several factors such as the nature of the nonwoven fiber web as
well as the nature of the resin being used. The determination of
appropriate abrasive material precursor add-on weights is well
within the skill of those practicing in the field.
[0073] Abrasive articles according to the present disclosure are
then achieved by at least partially curing the abrasive material
precursor, for example, using one or more of the techniques
described above.
[0074] Further details concerning abrasive articles and methods for
their manufacture may be found, for example, in U.S. Pat. No.
2,958,593 (Hoover et al.); U.S. Pat. No. 4,018,575 (Davis et al.);
U.S. Pat. No. 4,227,350 (Fitzer); U.S. Pat. No. 4,331,453 (Dau et
al.); U.S. Pat. No. 4,609,380 (Barnett et al.); U.S. Pat. No.
4,991,362 (Heyer et al.); U.S. Pat. No. 5,554,068 (Carr et al.);
U.S. Pat. No. 5,712,210 (Windisch et al.) U.S. Pat. No. 5,591,239
(Larson et al.); U.S. Pat. No. 5,681,361 (Sanders); U.S. Pat. No.
5,858,140 (Berger et al.); U.S. Pat. No. 5,928,070 (Lux); U.S. Pat.
No. 6,017,831 (Beardsley et al.); U.S. Pat. No. 6,207,246 (Moren et
al.); and U.S. Pat. No. 6,302,930 (Lux); and U.S. Pat. Appln. Publ.
2006/0041065 A1 (Barber, Jr.).
[0075] Abrasive articles according to the present disclosure have a
Stiffness Test (described hereinbelow) force (i.e., the maximum
force required to push the test fabric through the opening of the
testing fixture) of 0.1 to 5.0 pounds-force (0.4 to 020 N),
preferably 1.0 to 5.0 pounds-force (4.4 to 20 N), and more
preferably 2.0 to 5.0 pounds-force (8.9 to 20 N). In some
embodiments, Abrasive articles according to the present disclosure
have a Stiffness Test force of 2 to 4.5 pounds-force (9.0 to 2.3
kg-force). Greater stiffness associated with Stiffness Test force
values in excess of 5.0 pounds-force (020 N) results in
insufficient conformability of the abrasive article to conformable
to irregular surfaces and may result in undesirable wear patterns.
On the other hand, Stiffness Test force values of less than 0.1
lb-force (0.4 N) are typically associated with reduced mechanical
durability of the abrasive article.
[0076] For use with a rotary tool, abrasive articles may be secured
to a hooked backup pad such as, for example, a hooked low profile
finishing back up pad available from 3M Company under the trade
designation "3M HOOKIT DISC PAD". This may be particularly easy if
the major surface of the abrasive article opposite the major
surface proximate the abrasive material is essentially free of (or
even free of) abrasive material (i.e., including binder and
abrasive particles) that may inhibit the fibers from engaging with
hooks secured to the backup pad.
[0077] Abrasive articles according to the present disclosure may be
operated, for example, by hand or in combination with a power tool
such as for example, a rotary sander or belt sander. Abrasive
articles according to the present disclosure are useful for
abrading (including finishing) a workpiece by a method that
includes: frictionally contacting the abrasive material (i.e.,
first surface) first surface an abrasive article according to the
present disclosure with a workpiece (e.g., a finish layer disposed
on a substrate); and moving at least one of the substrate and the
abrasive article relative to the other to abrade at least a portion
of the finish layer. For example, the abrasive article may
oscillate at the abrading interface during use.
[0078] The workpiece can be any of a variety of types of material
such as, for example, painted substrates (e.g., having a clear
coat, base (color) coat, and/or primer or e-primer), clear coated
substrates (e.g., with polyurethane or lacquer), plastics
(thermoplastic, thermosetting), reinforced plastics, metal (e.g.,
carbon steel, brass, copper, mild steel, stainless steel, or
titanium) metal alloys, ceramics, glass, wood, wood-like materials,
composites, stones (e.g., natural stone and gem stones), stone-like
materials, and combinations thereof. The workpiece may be flat or
may have a shape or contour associated with it. Examples of common
workpieces that may be polished by the abrasive article of the
present disclosure include metal or wooden furniture, painted or
unpainted metal automotive body parts and accessories (e.g.,
fenders, rocker panels, side panels, roofs, doors, hoods, and
trunks), plastic automotive components (e.g., headlamp covers,
tail-lamp covers, other lamp covers, arm rests, instrument panels,
and bumpers), flooring (e.g., vinyl, stone, wood, and wood-like
materials), counter tops, boats, motorcycles, buses, railroad cars,
and airplanes.
[0079] During abrading processes it may be desirable to provide a
liquid to the surface of the workpiece and/or the abrasive article.
The liquid may comprise water, an organic compound, additives such
as defoamers, degreasers, liquids, soaps, corrosion inhibitors, and
the like, and combinations thereof.
Select Embodiments of the Present Disclosure
[0080] In a first embodiment, the present disclosure provides an
abrasive article having first and second major surfaces and
comprising:
[0081] a lofty open nonwoven fiber web comprising entangled fibers,
wherein the lofty open nonwoven fiber web further comprises:
[0082] a densified outer layer comprising a portion of nonwoven
fiber web proximate to the first major surface, wherein at least a
portion the entangled fibers in the densified outer layer are
melt-bonded to one another; and
[0083] an abrasive material coated on the densified outer layer,
wherein the abrasive material comprises abrasive particles retained
in a binder material, and wherein the abrasive particles have a
median particle diameter D.sub.50 in the range of 1 to 15 microns,
and
[0084] wherein the abrasive article has a Stiffness Test force of
0.1 to 5.0 pounds (0.45 to 2.27 kg) or less.
[0085] In a second embodiment, the present disclosure provides an
abrasive article according to the first embodiment, wherein the
lofty open nonwoven fiber web is needle-tacked.
[0086] In a third embodiment, the present disclosure provides an
abrasive article according to the first or second embodiment,
wherein a pre-bond resin is disposed on the lofty open nonwoven
fiber web substantially throughout its entirety.
[0087] In a fourth embodiment, the present disclosure provides an
abrasive article according to any one of the first to third
embodiments, wherein the second major surface is free of the
abrasive material.
[0088] In a fifth embodiment, the present disclosure provides an
abrasive article according to any one of the first to fourth
embodiments, wherein the abrasive article has a basis weight in the
range of from 200 to 400 grams per square meter.
[0089] In a sixth embodiment, the present disclosure provides an
abrasive article according to any one of the first to fifth
embodiments, wherein the first major surface is substantially
flat.
[0090] In a seventh embodiment, the present disclosure provides an
abrasive article according to any one of the first to sixth
embodiments, wherein the abrasive material is continuous.
[0091] In an eighth embodiment, the present disclosure provides an
abrasive article according to any one of the first to seventh
embodiments, wherein the abrasive particles conform to an abrasives
industry specified nominal grade in the range of from JIS 1000 to
JIS 6000.
[0092] In a ninth embodiment, the present disclosure provides a
method of buffing a workpiece, the method comprising:
[0093] frictionally contacting the first surface an abrasive
article according to any one of the first to eighth embodiments
with a workpiece; and
[0094] moving at least one of the workpiece and the abrasive
article relative to the other to abrade at least a portion of
workpiece.
[0095] In a tenth embodiment, the present disclosure provides a
method of buffing a workpiece according to the ninth embodiment,
wherein the workpiece comprises a finish layer disposed on a
substrate, and wherein the abrasive article abrades at least a
portion of the finish layer.
[0096] In an eleventh embodiment, the present disclosure provides a
method of buffing a workpiece according to the tenth embodiment,
wherein the finish layer comprises at least one of a paint or
clearcoat.
[0097] In a twelfth embodiment, the present disclosure provides a
method of buffing a workpiece according to the tenth or eleventh
embodiment, wherein the substrate comprises an automotive body
part.
[0098] Objects and advantages of this disclosure are further
illustrated by the following non-limiting 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 disclosure.
EXAMPLES
[0099] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by weight. As
used herein the abbreviation "phr" means parts per hundred by
weight.
Materials
[0100] Table 1 (below) lists materials used in the Examples.
TABLE-US-00001 TABLE 1 Fiber1 15 denier (17 dtex) .times. 1.57
inches (40 mm) length Nylon 6 fiber obtained from EMS CHEMIE,
Austria Fiber2 6 denier (6.7 dtex) .times. 1.50 inches (38.1 mm)
length Nylon 66 fiber, C113, Merge 1V197, obtained from INVISTA,
Lugoff, South Carolina Fiber3 40 denier (44 dtex) .times. 2.10
inches (53.3 mm) length Nylon 66 fiber produced by traditional
means Fiber4 15 denier (16.7 dtex) .times. 1.25 inches (32 mm)
length Polyester fiber, TYPE 295, obtained from INVISTA, Lugoff,
South Carolina Fiber5 4 denier (4.4 dtex) .times. 2 inches (51 mm)
length low melt Polyester fiber, TYPE 4080, obtained from Unitika,
Japan Fiber6 58 denier (64.4 dtex) .times. 2.10 inches (53.3 mm)
length fiber, a polymer blend of 50 phr of Nylon 6 and 50 phr of
Nylon 66 produced by traditional means BL16 Polyurethane
prepolymer, obtained as ADIPRENE BL-16 from Chemtura Group,
Middlebury, Connecticut K450 Aromatic amine curing agent, LAPOX
K-450, obtained from Royce International, East Rutherford, New
Jersey PMA Propylene glycol monomethyl ether acetate, DOWANOL PMA
484431, obtained from Sigma Aldrich, St. Louis, Missouri WATER Tap
water PME Propylene Glycol Monomethyl Ether, from Dow Chemical
Corporation, Midland, Michigan GEO Anti-foam agent, obtained as GEO
FM LTX from GEO Specialty Chemicals, Ambler, Pennsylvania SR511 75
percent by weight of hydroxyethylethylene urea in water, obtained
as SR511 from Sartomer Inc., Exton, Pennsylvania DYNOL Surfactant,
obtained as DYNOL 604 from Air Products and Chemicals Inc.,
Allentown, Pennsylvania PR Phenolic resin obtained as PREFERE 80
5077A from Arclin, Roswell, Georgia TERGITOL Surfactant, obtained
as TERGITOL 15-S-5 from Dow Chemical Company, Midland, Michigan SIA
3-Aminopropyltriethoxysilane, obtained from Gelest Inc.
Morrisville, PA, as SIA0610 CABOSIL Silicon dioxide, obtained as
CAB-O-SIL Untreated Fumed Silica, M-5 from Cabot Corp., Cambridge,
Massachusetts C2500 Black silicon carbide mineral, available as C
2500 BLACK SILICON CARBIDE, D.sub.50 = 5.6 .+-. 0.5 microns, from
Fujimi Corp, of Tualatin, Oregon GC3000 Green silicon carbide
mineral, available as GC 3000 GREEN SILICON CARBIDE, D.sub.50 = 4.0
.+-. 0.5 microns, from Fujimi Corp. GC4000 Green silicon carbide
mineral, available as GC 4000 GREEN SILICON CARBIDE, D.sub.50 = 3.0
.+-. 0.4 microns from Fujimi Corp. GC6000 Green silicon carbide
mineral, available as GC 6000 GREEN SILICON CARBIDE, D.sub.50 = 2.0
.+-. 0.4 microns from Fujimi Corp. PWA5 White Aluminum Oxide
mineral, available as PWA 5 ALUMINUM OXIDE, D.sub.50 = 4.7 .+-. 0.4
microns from Fujimi Corp.
Test Methods
Basis Weight
[0101] The basis weight of the nonwoven samples was determined in
accordance with ASTM D6242-98 "Standard Test Method for Mass Unit
Area of Nonwoven Fabrics". All samples were conditioned at 65.+-.2%
relative humidity and 21.+-.1.degree. C. prior to testing. Five (5)
specimens having area of 24 in.sup.2 (0.015 m.sup.2) were cut from
each lot and weighed. The web basis weight was determined by
dividing the mass of the specimen in grams by specimen area in
square meters (gsm).
Thickness
[0102] The thickness of nonwoven fiber webs was determined as the
distance between the upper and the lower surfaces of the material,
measured under a specified pressure, in accordance with ASTM
D5729-97 "Standard Test Method for Thickness of Nonwoven Fabrics".
A DIGIMATIC indicator (Mitotoyo America, Aurora, Ill.) was used to
measure thickness of the webs. The pressure foot for this test had
a diameter of 3.5 inches (88.9 mm), and the applied load was 0.5
lbs (226.8 grams). Five (5) specimens were tested from each lot,
and the average was reported
Testing Fixture A
[0103] Scale views of Testing Fixture A are shown in detail in
FIGS. 5A-5B. Testing fixture A (500) was fabricated from metal. Key
dimensions were as follows: .alpha.=34.degree.; h=0.563 inch
(1.43); d1=1.80 inches (4.57 cm); d2=2.36 inches (5.99); and
d3=3.15 inches (8.00 cm).
Stiffness Test
[0104] Stiffness of abrasive articles was measured using a
Thwing-Albert (Philadelphia, Pa.) ELECTRONIC TENSILE TESTER
equipped with a 200-pound (890 N) load cell and pneumatic grips.
Referring now to FIGS. 5A and 5B, Testing Fixture A (500) was
inserted into pneumatic grips with the bottom grip pulling on the
fixture at a speed of 7.8 inch/min (19.8 cm/min) during testing.
Four discs with diameters of 4.0 inches (10.2 cm) were cut from
each nonwoven abrasive article and placed with abrasive material
side up into disc holder 560 in the top side of fixture 510 having
a tapered aperture with top diameter d3 of 3.15 inch (8.00 cm) and
inner bottom diameter d2 of 2.36 inches (5.99 cm). As the bottom
pneumatic grip pulled on the fixture, a 1.8 inch (4.57 cm) diameter
circular probe 550 moved downwards until it pushed the 4 inch (10.2
cm) diameter abrasive disc through the tapered aperture. The amount
of force in pounds required to push the abrasive disc through the
aperture was measured and reported.
Flatness Test Procedure
[0105] Test specimens (0.5.times.12 in (1.27.times.30.48 cm)) of
abrasive article to be evaluated were cut from the original web
sample in the cross-web direction using a razor blade. A test
specimen was placed between two 0.5.times.12 in (1.27.times.30.48
cm) steel bars with the freshly cut edge aligned with the top of
both bars to expose a cross-section for microscopic examination of
the flatness of each specimen. A confocal microscope with built-in
measurement tools (KEYENCE VK9710 from Keyence Corporation, Elmwood
Park, N.J.) at 20.times. magnification was used to measure both
high and low deviations of the heat treated side from planarity. A
minimum of 6 measurements (microns) were recorded, averaged, and
reported in Table 3.
Polishing Test
Procedure I:
[0106] The workpieces were 18 in.times.24 in (46 cm.times.61 cm)
automotive base coat/color coat/clear coat (DuPont RK8148) test
panels (obtained from ACT Laboratories, Hillsdale, Mich.).
[0107] The test panels were prepared by sanding the entire surface
of the panel using a random orbital sander (3M ELITE SERIES 5-IN,
NON-VACUUM, 3/32-IN ORBIT, PN: 28498, obtained from 3M, Saint Paul,
Minn.) fitted with a low profile finishing disc pad (3M HOOKIT DISC
PAD, 5-in.times.5/16-24 EXT, PN: 77855, from 3M Company) and a
P1500 grade abrasive (3M HOOKIT FILM DISC 375L, 5.times.NH P1500,
PN: 55709, from 3M Company). The operating air pressure was
maintained at 90 psi (345 KPa). The sanding assembly was placed in
contact with the selected test panel section and activated.
Beginning in the upper left corner of the panel, the sander was
traversed in a left-to-right, right-to-left pattern, indexing down
to provide a 50 percent area overlap of each prior pass; and
finally in a top-to-bottom, bottom-to-top pattern, indexing right
to provide a 50 percent area overlap of each prior pass. The
sanding step was repeated until the entire surface was evenly
abraded. The sanding residue was removed by wiping with a soft
cloth.
[0108] Following the preparation step, the imparted scratches were
further refined with the inventive and comparative abrasive
articles. The test panel was divided into four 6 in.times.18 in (15
cm.times.46 cm) sections and each section was abraded with an
Example 5 in (12.7 cm) diameter nonwoven abrasive disc, used on the
same sander and disc pad as described in the preparation step. The
sander was moved forward and back to abrade the selected section.
For each section, the total sanding time was 40 seconds. The
sanding residue was removed by wiping with a soft cloth.
[0109] Following sanding, the panel was buffed with an electric
buffer (3M ELECTRIC VARIABLE SPEED POLISHER, PN: 28391, obtained
from 3M Company), fitted with a pad adapter (3M QUICK CONNECT
ADAPTER, PN: 05750, obtained from 3M Company), an 8'' polishing pad
(3M PERFECT-IT FOAM COMPOUNDING PAD, PN: 05706, obtained from 3M
Company), and a compound (3M PERFECT-IT RUBBING COMPOUND, PN:
39060/pint, obtained from 3M Company). The buffing pad was
conditioned by applying a thin, even coating of compound. Compound
was applied to the test area to be buffed and distributed using the
face of the mounted buffing pad. The buffer was placed in contact
with the test area and activated. The buffer was operated in the
same pattern as described in the preparation step. Residual
compound was removed by wiping with a soft cloth.
[0110] Following buffing, the panel was polished using the same
buffer, adapter, and method as described in the compounding step.
Polishing was completed using an 8-inch diameter polishing pad (3M
PERFECT-IT FOAM POLISHING PAD, PN: 05707, obtained from 3M Company)
and machined polish (3M PERFECT-IT MACHINE POLISH, PN: 39061,
obtained from 3M Company). Each test area was inspected for "wild"
scratches and leveling characteristics (reduction of orange peel)
in the test area of the panel. Examples passed the buffing test if
the orange peel was leveled and there were very few, preferably no
scratches remaining on the test panel.
Procedure II
[0111] This procedure was identical to Procedure I, except that a
3M HOOKIT FINISHING FILM DISC, 260L, 6 inch, P1500 grit (PN:
00950), was substituted for the 375L disc.
Abrasive Article Preparation
Example 1
[0112] An air-laid lofty nonwoven fiber web was prepared from a
fiber blend consisting of 50 phr of Fiber1, 25 phr of Fiber2, and
25 phr of Fiber3 using a RANDO-WEBBER machine, obtained from Rando
Machine Corporation of Macedon, N.Y. The web was needle-tacked
using traditional barbed needles with a spacing of 25 needles per
inch (10 needles per cm) at line speed of 3.4 m/min and stroke
speed of 290 strokes/min. The needle penetration was 8 mm. The web
was then calendered at 218.degree. C. under 45 psi (310 kPa) of
pressure. The web was further conveyed to a horizontal two-roll
coater, where a prebond resin containing 73.6 phr of PMA, 19.3 phr
of BL16, and 7.1 phr of K450 was applied to the fiber web at the
dry add-on weight of 26 grains/24 square inches (109 gsm). The
coated web was conveyed through a forced-convection oven maintained
at between 149 and 163.degree. C. with a residence time of 3
minutes. The resulting prebond-treated lofty fiber web had a
nominal basis weight of 77 grains per 24 square inches (323 gsm),
and the thickness was 0.257 inches (6.53 mm).
[0113] The resultant prebond resin-coated and cured lofty fiber web
was then conveyed into a spray booth, which contained spray nozzles
that reciprocated perpendicularly to the direction of prebond
travel. These spray nozzles were used to spray an abrasive slurry
containing 22.21 phr of WATER, 3.70 phr of PME, 0.002 phr of GEO,
1.73 phr of SR511, 0.09 phr of DYNOL, 17.38 phr of PR, 0.87 phr of
TERGITOL, 0.19 phr of CABOSIL, and 53.83 phr of GC3000 onto the top
side of the web. The wet slurry add-on weight was 20 grains/24
square inches (84 gsm).
[0114] The resulting abrasive web was heated in a forced-convection
oven set at 177.degree. C. for 2 minutes to cure the abrasive
slurry. The final nonwoven abrasive web was about 0.270 inches (6.9
mm) thick and weighed about 95 grains/24 square inches (399 gsm).
Discs (5-in (12.7 cm) diameter) were cut from the nonwoven abrasive
web for testing. Polishing Test Procedure I was used.
Example 2
[0115] Example 1 was repeated, except for the following changes.
The dry prebond resin add-on weight was 7 grains/24 square inches
(29 gsm). The resulting prebond resin-coated and cured lofty fiber
web had a nominal basis weight of 64 grains/24 square inches (269
gsm), and the thickness was 0.259 inches (6.6 mm). The prebond
resin-coated and cured lofty fiber web was sprayed with an abrasive
slurry containing 7.0 phr of WATER, 23.5 phr of PME, 0.002 phr of
GEO, 1.6 phr of SR511, 0.09 phr of DYNOL, 16.5 phr of PR, 0.9 phr
of TERGITOL, 0.40 phr of CABOSIL, 0.9 phr of SIA and 49.0 phr of
GC6000. The wet abrasive slurry add on was 23 grains/24 square
inches (97 gsm). The final nonwoven abrasive was about 0.282 inches
(7.2 mm) thick and weighed about 84 grains/24 square inches (353
gsm). Polishing Test Procedure II was used. FIG. 2A shows the
heat-treated nonwoven fiber web (densified layer on upper surface)
used in Example 2. FIG. 2B shows the abrasive article (abrasive
material on upper surface) made in Example 2.
Example 3
[0116] Example 1 was repeated, except for the following changes.
The nonwoven fiber web was made using 80 phr of Fiber 4 and 20 phr
of Fiber 5. The web was calendered at 166.degree. C. under 45 Psi
(310 kPa) of pressure. The web was roll coated using the same
prebond resin as Example 1 to achieve a dry add-on weight of 7
grains/24 square inches (29 gsm). The resultant prebond
resin-coated and cured lofty fiber web had a nominal basis weight
of 63 grains/24 square inches (264 gsm), and the thickness was
0.335 inches (8.5 mm). The wet abrasive slurry add on was 20
grains/24 square inches (84 gsm). The final nonwoven abrasive was
about 0.351 inches (8.9 mm) thick and weighed about 76 grains/24
square inches (319 gsm). Polishing Test Procedure I was used.
Example 4
[0117] Example 1 was repeated, except for the following changes.
The nonwoven fiber web was made using 70 phr Fiber 6 and 30 phr
Fiber 2. The web was roll coated using the same prebond resin as
Example 1 to achieve a dry add-on weight of 4 grains/24 square
inches (17 gsm). The resultant prebond resin-coated and cured lofty
fiber web had a nominal basis weight of 71 grains/24 square inches
(297 gsm), and the thickness was 0.262 inches (6.7 mm). The wet
abrasive slurry add on was 20 grains/24 square inches (84 gsm). The
final nonwoven abrasive was about 0.260 inches (6.6 mm) thick and
weighed about 80 grains/24 square inches (335 gsm). Polishing Test
Procedure I was used.
Example 5
[0118] Example 1 was repeated, except for the following changes.
The dry prebond resin add-on weight was 5 grains/24 square inches
(21 gsm). The resultant prebond resin-coated and cured lofty fiber
web had a nominal basis weight of 46 grains/24 square inches (193
gsm), and the thickness was 0.179 inches (4.5 mm). The wet abrasive
slurry add on was 16 grains/24 square inches (67 gsm). The final
nonwoven abrasive was about 0.181 inches (4.6 mm) thick and weighed
about 57 grains/24 square inches (239 gsm). Polishing Test
Procedure I was used.
Example 6
[0119] Example 1 was repeated, except for the following changes.
The dry prebond resin add-on weight was 4 grains/24 square inches
(17 gsm). The resultant prebond resin-coated and cured lofty fiber
web had a nominal basis weight of 77 grains/24 square inches (323
gsm), and the thickness was 0.297 inches (7.5 mm). The wet abrasive
slurry add on was 20 grains/24 square inches (84 gsm). The final
nonwoven abrasive was about 0.307 inches (7.8 mm) thick and weighed
about 89 grains/24 square inches (374 gsm). Polishing Test
Procedure I was used.
Example 7
[0120] Example 1 was repeated, except for the following changes.
The web was calendered at 207 degrees C..degree. under 80 Psi (552
kPa) pressure. The web was roll coated using a resin containing
61.0 phr of PMA, 30.0 phr of BL16, and 9.0 phr of K450 to achieve a
dry add-on weight of 18 grains/24 square inches (75 gsm). The
resultant prebond resin-coated and cured lofty fiber web had a
nominal basis weight of 71 grains/24 square inches (297 gsm), and
the thickness was 0.216 inches (5.5 mm). The prebond resin-coated
and cured web was sprayed with an abrasive slurry containing 22.21
phr of WATER, 3.70 phr of PME, 0.002 phr of GEO, 1.73 phr of SR511,
0.09 phr of DYNOL, 17.38 phr of PR, 0.87 phr of TERGITOL, 0.19 phr
of CABOSIL, and 53.83 phr of C2500. The wet abrasive slurry add on
was 15 grains/24 square inches (63 gsm). The final nonwoven
abrasive was about 0.242 inches (6.1 mm) thick and weighed about 82
grains/24 square inches (343 gsm). Polishing Test Procedure I was
used.
Example 8
[0121] Example 1 was repeated, except for the following changes.
The dry prebond resin add-on weight was 12 grains/24 square inches
(50 gsm). The resulting lofty fiber web had a nominal basis weight
of 76 grains/24 square inches (318 gsm), and the thickness was
0.269 inches (6.8 mm). The resultant prebond resin-coated and cured
lofty fiber web was sprayed with an abrasive slurry containing
17.40 phr of WATER, 2.90 phr of PME, 0.001 phr of GEO, 1.37 phr of
SR511, 0.07 phr of DYNOL, 13.76 phr of PR, 0.69 phr of TERGITOL,
0.15 phr of CABOSIL, and 63.66 phr of PWA5. The wet abrasive slurry
add on was 22 grains/24 square inches (92 gsm). The final nonwoven
abrasive was about 0.277 inches (7.0 mm) thick and weighed about 92
grains/24 square inches (385 gsm). Polishing Test Procedure I was
used.
Example 9
[0122] Example 1 was repeated, except for the following changes.
The dry prebond resin add-on weight was 6 grains/24 square inches
(25 gsm). The resulting lofty fiber web had a nominal basis weight
of 61 grains/24 square inches (256 gsm), and the thickness was
0.248 inches (6.3 mm). The resultant prebond resin-coated and cured
lofty fiber web was sprayed with an abrasive slurry containing
22.21 phr of WATER, 3.70 phr of PME, 0.002 phr of GEO, 1.73 phr of
SR511, 0.09 phr of DYNOL, 17.38 phr of PR, 0.87 phr of TERGITOL,
0.19 phr of CABOSIL, and 53.83 phr of GC4000. The wet abrasive
slurry add on was 19 grains/24 square inches (80 gsm). The final
nonwoven abrasive was about 0.259 inches (6.6 mm) thick and weighed
about 80 grains/24 square inches (336 gsm). Polishing Test
Procedure II was used.
Comparative Example A
[0123] Example 1 was repeated except for the following changes. The
prebond resin-coated fiber web was calendered a second time at
249.degree. C. under 110 Psi (758 kPa) of pressure, and roll coated
a second time to achieve a total dry resin add-on weight of 23
grains/24 square inches (97 gsm). The resultant prebond
resin-coated and cured lofty fiber web had a nominal basis weight
of 83 grains/24 square inches (348 gsm), and the thickness was
0.187 inches (4.7 mm). The resin coated and cured web was sprayed
with the abrasive slurry used in Example 1 at 14 fpm (4.3 m/min).
The wet abrasive slurry add on was 18 grains/24 square inches (76
gsm). The final nonwoven abrasive was about 0.174 inches (4.4 mm)
thick and weighed about 95 grains/24 square inches (399 gsm).
Polishing Test Procedure I was used.
Comparative Example B
[0124] Example 1 was repeated except for the following changes. The
web was needle tacked at a stroke speed of 170 strokes/min and the
dry prebond resin add-on weight was 17 grains/24 square inches (71
gsm). The resultant prebond resin-coated and cured lofty fiber web
had a nominal basis weight of 68 grains/24 square inches (285 gsm),
and the thickness was 0.270 inches (6.9 mm). The prebond
resin-coated and cured web was sprayed using the same conditions
and abrasive slurry used for Example 1. The wet abrasive slurry add
on was 18 grains/24 square inches (76 gsm). The final nonwoven
abrasive was about 0.256 inches (6.5 mm) thick and weighed about 78
grains/24 square inches (327 gsm). Polishing Test Procedure I was
used. FIG. 3A shows the heat-treated nonwoven fiber web (densified
layer on upper surface) used in Comparative Example B. FIG. 3B
shows the abrasive article (abrasive material on upper surface)
made in Comparative Example B.
Comparative Example C
[0125] Comparative Example A was repeated, except for the following
changes. The prebond resin-coated and cured web was sprayed with
the abrasive slurry used in Example 1 at 20 fpm (6.1 m/min). The
wet abrasive slurry add on was 18 grains/24 square inches (76 gsm).
The final nonwoven abrasive was about 0.188 inches (4.8 mm) thick
and weighed about 149 grains/24 square inches (625 gsm). Polishing
Test Procedure I was used.
Comparative Example D
[0126] Example 1 was repeated except for the following changes. The
web was not heat-treated and dry prebond resin add-on weight was 11
grains/24 square inches (46 gsm). The resultant prebond
resin-coated and cured lofty fiber web had a nominal basis weight
of 66 grains/24 square inches (277 gsm), and the thickness was
0.398 inches (10.1 mm). The prebond resin-coated and cured web was
sprayed with the abrasive slurry used in Example 1 at 20 fpm (6.1
m/min). The wet abrasive slurry add on was 18 grains/24 square
inches (76 gsm). The final nonwoven abrasive was about 0.403 inches
(10.2 mm) thick and weighed about 80 grains/24 square inches (336
gsm). FIG. 4A shows the non-heat-treated nonwoven fiber web
(prebond applied to top surface) used in Comparative Example D.
FIG. 4B shows the abrasive article (abrasive material on upper
surface) made in Comparative Example D. Polishing Test Procedure I
was used.
Comparative Example E
[0127] Example 1 was repeated except for the following changes. The
dry prebond resin add-on weight was 6 grains/24 square inches (25
gsm). The resultant prebond resin-coated and cured lofty fiber web
had a nominal basis weight of 76 grains/24 square inches (319 gsm),
and the thickness was 0.352 inches (8.9 mm). The prebond
resin-coated and cured web was sprayed with the abrasive slurry
used in Example 1 at 20 fpm (6.1 m/min). The wet abrasive slurry
add on was 18 grains/24 square inches (76 gsm). The final nonwoven
abrasive was about 0.372 inches (9.4 mm) thick and weighed about 96
grains/24 square inches (403 gsm). Polishing Test Procedure I was
used.
Test Results
[0128] Examples 1 through 9 and Comparative Examples A through C
were tested according to the Hand Flex Test and the Polishing Test.
The results are reported in Tables 2 and 3, below.
TABLE-US-00002 TABLE 2 PREBONDED NONWOVEN FIBER WEB THICKNESS,
BASIS WEIGHT, EXAMPLE in (mm) 2 grains/24 in.sup.2 (gsm) 1 0.257
(6.5) 77 (323) 2 0.259 (6.6) 64 (269) 3 0.335 (8.5) 63 (264) 4
0.262 (6.7) 71 (298) 5 0.179 (4.5) 46 (193) 6 0.297 (7.5) 77 (323)
7 0.216 (5.5) 71 (298) 8 0.269 (6.8) 76 (319) 9 0.248 (6.3) 61
(256) Comparative 0.187 (4.7) 83 (348) Example A Comparative 0.270
(6.9) 68 (285) Example B Comparative 0.187 (4.7) 83 (348) Example C
Comparative 0.398 (10.1) 66 (277) Example D Comparative 0.352 (8.9)
76 (319) Example E
TABLE-US-00003 TABLE 3 ABRASIVE ARTICLE - FULL CONSTRUCTION BASIS
STIFFNESS FLATNESS WEIGHT, TEST, TEST, microns POLISHING POLISHING
THICKNESS, grains/24 in.sup.2 pound-force STD. TEST TEST RESULT,
EXAMPLE in (mm) (gsm) (kg-force) MEAN DEV. PROCEDURE Pass (P) or
Fail (F) 1 0.270 (6.9) 95 (399) 4.5 (2.0) 293 62.6 I P 2 0.282
(7.2) 84 (353) 3.3 (1.3) 329 46.0 II P 3 0.351 (8.9) 76 (319) 4.5
(2.0) 287 56.5 I P 4 0.260 (6.6) 80 (336) 1.7 (0.8) 284 36.7 I P 5
0.181 (4.6) 57 (239) 1.0 (0.5) 239 57.1 I P 6 0.307 (7.8) 89 (374)
1.8 (0.8) 304 44.0 I P 7 0.242 (6.1) 82 (344) 5.0 (2.3) 265 68.5 I
P 8 0.277 (7.0) 92 (386) 3.0 (1.4) 265 57.3 I P 9 0.259 (6.6) 80
(336) 3.6 (1.7) 296 47.1 II P Comparative 0.174 (4.4) 95 (399) 6.4
(2.9) 248 27.2 I F Example A Comparative 0.256 (6.5) 78 (327) 5.9
(2.7) 616 89.0 I F Example B Comparative 0.188 (4.8) 149 (625) 5.5
(2.5) 531 48.4 I F Example C Comparative 0.402 (10.2) 77 (323) 3.7
(1.7) 736 86.7 I F Example D Comparative 0.372 (9.4) 96 (403) 5.6
(2.5) 711 198.0 I F Example E
[0129] All cited references, patents, or patent applications in the
above application for letters patent are herein incorporated by
reference in their entirety in a consistent manner. In the event of
inconsistencies or contradictions between portions of the
incorporated references and this application, the information in
the preceding description shall control. The preceding description,
given in order to enable one of ordinary skill in the art to
practice the claimed disclosure, is not to be construed as limiting
the scope of the disclosure, which is defined by the claims and all
equivalents thereto.
* * * * *