Note: Descriptions are shown in the official language in which they were submitted.
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W O 97/07937 PCT~US96/13941
NONWOVEN ABRASIVE MATERIAL ROLL
r BACK~ROUNl~ OF THE D~VENTION
The present invention relates to surface cnnflitiQning products, and sperifir~lly to
S surface confiitif)ning sheets co~ .li~lg a lofty, non-woven abrasive article. The abrasive
article can be provided to the user in roU form. The roll material has sllrf~r~rc which
illlelGll~7~e ~lffiri~ntly to .,.~;..1~;.~ the roU in a spiraUy wrapped confi~lration7 yet are
sep~ to allow roU ullwilliing. The roU is pGIrul~Led to permit sheet separation and
removal LhclGLum.
The low density abrasive products ofthe type defined in U.S. Patent No. 2,958,593
and sold under the df~eign~tion "SCOTCH-BRITE" by Min,~esola Mining and
M~mlfilchlring Company of St. Paul, Mil~.lesoL~, have found .ei~nifir~nt c~ -GI~;al success
as surface LlcaLIll~,.ll products. This type of abrasive product is typicaUy formed of crimped
staple fibers which have been formed into a mat and inl~ ed with resinous binder and
abrasive. This material is made available cfillllll~l~;;ally in a wide variety oftypes to provide
many fimctinne It can be formed as a disc or wheel for mounting on a rotating axis, a belt,
a pad for 1~ eqllipmf~nt such as floor treating pads or in sheet form for use as a hand
pad. In this latter regard, cut sheets have been provided for use as hand pads in surface
r;"'~l';'~g appli~ti~ne, such as ~7Llip~illg, sc~-ffing, rl~ or ~ -g work. Such sheets
were provided to users in pre-cut for n, sold individuaUy or p~rL ~ge-3 in stacked forrn.
Such nonwoven abrasive material has also been available in roll form, typically wound on a
support core (such as a cardboard core), and then lengths of nonwoven material could be
cut to length as desired and removed from the roU.
In use, nonwoven abrasive material hand pads have dicpl ~~efi (in many ;..~ res)25 steel wool pads as the desired surface confiitioning product. Steel wool pads shed metaUic
particles during use, which can lead to numerous pl ubl - (e.g., finish illlpel re-;Lions, rust
_. stains, annoying or injurious ~7~ 7 in a user's fingers, etc.). In addition, steel wool pads
tend to snag or tear during use, becoming non-uniform in terrns of abrasive qnAlitif~e and
1~AI~f11;~g characteristics. One advantage that steel wool pads had over the prior art
30 nonwoven abrasive material hand pads, however, was their cul~llllabiliLy. The user was
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able to shape (e.g., fold or configure) a steel wool pad to desired configurations, depending
upon the particular applir,atic n, and the pad would retain that general shape. Prior art
nonwoven abrasive material hand pads, while avoiding the problem of.ehPfi~1ing particles,
have not been suitably ~O,~rO. l~!e for the end user, and could not retain a folded or
wadded shape. Even though the faces of the prior art nonwoven abrasive material pads are
rough (i.e., abrasive) in nature, they do not engage or adhere on contact with one another.
This feature, in ~I-lI)in~ioll with the ~ ,L ~ IP~;, stiffness and weight of the prior art
nonwoven abrasive material prevented such material from "~ ,.;"il~g a folded or wadded
configuration. Another advantage that steel wool pads had over the prior nonwoven
abrasive material hand pads was the ability to achieve a fine surface finish while providing a
desired Bearing Ratio on the abraded surface.
As mPntinnecl above, prior nonwoven abrasive material has been provided to end
users only in discrete hand pad or roll form. In the course of m~mlf~rt~lrin~ such
nonwoven abrasive materials to form discrete hand pads, it has been known to form a
Inn~h-din~lly rxtf~nriin~ web of nonwoven abrasive material (such as web 11 in FIG. 1)
which is seq ~Pnti~lly cut laterally, as at 13, into a plurality of intermediate web sections 15.
Each web section 15 is then subjected to a longih~rlin~lly-disposed severing, along a
plurality of separation lines 17, to form a plurality of pad members 19 Lllt;l~iUIII. The
St:;v~ll~ at each line 17 is not - ~ , k ~ (a few strands of the nonwoven material are left
uncut b~Lween~ ar~nt pad Ill~lllI)el~ 19), so the pad members 19 remain cQ~Ill~lecl as a
web section 21. Each web section 21 may be further processed for one or more
m~mlf~r,hlring steps, inrllldingthe .QtarLin~ of several web sections 21, as illustrated at 23.
Adjacent stacks 25 of pad members 19 are separated by relative vertical movement (see,
e.g., arrows 27 and 29) to break the few strands of nonwoven material that connect
a~liacent pad members 19 ofthe same web section 21, into in-process stacks 25. Each
s~ e stack 25 of pad members 19 is then further processed and parL~gPci for
~li~rihlltion to end users, where each pad ll.c;..-l~er 19 thus cQn~tit~-te~ a discrete, nonwoven
abrasive hand pad.
Mirka, a Finnish collll~ly, has sold prior art nonwoven abrasive material in roll
30 form, under the mark "MIRLON," where the roll of material (which is not self-~nga in~) is
encased in a shr~nk-wrap material as delivered to the end user. The nonwoven abrasive
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m~t~ l is removed from this roll by unwinding it off of the innermost wrap of the roll,
from ~ nt the central axis of the roll, and cutting a piece to whatever length is desired.
- SUMMARY OF THE lNVENlION
The present invention provides an improved means for p~ ging delivering and
5 ~ g lofty nonwoven abrasive surface treatment material. A lc)ngitll~lin~lly ~t~nrling
web of such material is improved by providing a plurality of longitl ~~lin~lly spaced and
laterally disposed we~k~n~ areas along the web to permit a user to readily and
~s~ cively sep~ ~e the web into a plurality of sheets of abrasive surface ll G~lllllGlll
m~tPri~l In a plGrGlled embodiment, each we~k~ned area is defined by pelro-~ions formed
10 through the web.
A roll of lofty, nonwoven abrasive surface llGallllGlll material is improved by
forming a roll to be self-binding, with s ~ ive wraps of the nonwoven material having
opposed surfaces which ~l.~e.engage sllffi~;~ntly to ...~ ;.. the nonwoven material in a
spirally-wrapped confi~lration~ yet are .sllffi~;ently (1i.~n~ge~hle to permit u..wl..d.l-g of
15 material from the roll. A nonwoven material having such surface characteristics can be
folded or wadded into a desired shape and will hold such shape, without imm~ t~ly
~1.. ;..~..p. open to a more n,1n f~l~P~ state. Thus, a single sheet of such a material can be
.led to a shape as desired by the end user.
In a p- GrGI ~ ~d embodiment, the nonwoven abrasive material is wrapped spirally20 about itself to form a roll which is coreless. The material is unwound or removed from the
roll from a~ia~nt its innermost wrap, and a 1~ ~te ,li~e sheath is disposed about an
outermost wrap ofthe roll. P-Gr~-~ly, the sheath is formed from a shrink-wrap process
and, if desired, may bear product identifying indicia thereon.
In another plerG..Gd embodiment, the nonwoven abrasive article has an
25 abrasive particle size and distribution which imparts a surface finish having values of
Ra less than 10 microinches and a Bearing Ratio of between 15 and 60 percent, more
preferably between 15 and 50 percent, and still more preferably between 15 and 40
percent. Such a nonwoven abrasive article is especially well-suited for scllffing
automotive finishes prior to the application of subsequent coatings, for example.
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W Og7/07937 PCT~US96/13941
BRIEF DESCRlPTION OF T~ DRAWINGS
The present invention wiU be more fuUy described with reference to the
~c~ .A"ying drawings, wherein like reference numerals identify col-~,pollding
col~.pollents.
SFIG. 1 is a s~h~ illustration of a portion of a prior art process for
m~nllf~lring nonwoven abrasive material hand pads.
FIG. 2 is an i.comlotric view of a roU of nonwoven material which is lateraUy
pe. rù. ~led into secti- n~ acco~ ding to the tçs~hing.c of the present invention.
FIG. 3 is an isometric view of the roU of FIG. 2 aligned in a dispenser for holding
10the roU and readily li~.el~"lg successive sheets Lhel~iulll.
FIG. 4 is an isometric view of a sheet from the roll which has been folded for use.
FIG. 5 is an isometric view of a sheet from the roll which has been crumpled for use.
FIG. 6 is an isometric view ofthe roU of FIG. 2, encased in a p-uLe~;Li~e sheath.
15While the above-i tentifi~i drawing features set forth ~-c;r~--c d embodiments, other
embodiments ofthe present invention are also cc""~."pl,.l~l as noted in the discussion.
The disclosure ~l~st;lll~ iUustrative embodirnents ofthe present invention by way of
~p~ l;on and not limit~tic-n Numerous other modifications and embo tim~nt~ can be
devised by those skilled in the art, which faU within the scope and spirit of the principles of
20 this invention. The d.~i~, figures have not been drawn to scale as it has been n~?c~.c~, y
to enlarge or ~."pt~;,e certain features for clarity of.ep.ese..la~ion.
DETAILEI~ DESCRIPTION OF THE PREE7~ EMBODIMENTS
FlG. 2 iUustrates a roU of nonwoven abrasive surface Ll eal...~;.-L material formed and
configured for use in co~ e.;lion with the present invention. The nonwoven abrasive
25 material, described in more detail below, is initiaUy formed as a Inngitu tin~l web 30, which
is then spirally wrapped on a lateraUy disposed axis and configured as a roU 32. The web
30 is generally unitary in formation, and has i~ .nr~ lly spaced w~kt~n~d areas across
the web, as in-ii~ ted by perforations 34. Individual sheets or sections 36 of nonwoven
abrasive material can thus be s~u,LLed from the roU 32 successively, along their .es~e~ e
30 perforations 34.
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--5--
As seen in FIG.2, the roll 32 is coreless (i.e., there is no core or central mandrel of
other material centraUy SU~pOI Lillg the roll 32 in its final form as provided to the end user).
A central cylindrical hole or opening 38 is left a~ c~nt the irmermost wrap ofthe roll 32 to
permit access to its interior (i.e., to the nonwoven abrasive material ofthe i~ llllo~L wrap).
5 As seen in FIG.3, the sheets 36 are plc;r~ ~bly s~ led from the roU 32 in a center-puU or
center feed manner, being removed stlcc~e~ively from the end of the roU's innermost wrap.
A ~ e~ 40 in~ des at least a side waU 42 surrounding the roU 32 and a bottom waU 44
stll-pol Ling the roU 32. The roU 32 can be loaded within the ~ e~. 40 so that its central
oper~ing 38 is aligned with a central port 46 in the bottom waU 44, to permit access to the
10 end ofthe innermost wrap ofthe roU 32. Single sheets 36 can then be ~cc~eced from the
innermost wrap and readily sepal~Led from the r~m~in-l~r ofthe roll 32 along pt;lrul~lions
34, as desired by a user (such as by puUing on the exposed sheets in direction of arrow 48,
as in FIG~ 3, and particularly on end sheet 36a). The di~ellsel 40 is suitably adapted for
llluullLillg, such as on a waU, stand or other support, at a height and location for ready user
15 acce~;~il,iliLy. AU ofthe sheets 36 on a roU 32 can be ~ eed in this manner, until the roll
in the dis~.ellsel is used up and needs to be n~ ' with a new roll of nonwoven
abrasive surfiace Ll~llc;lIL material.
The lofty nonwoven abrasive surface treatment material itself has certain desired
~,L,.I~ t~ ,e The nonwoven abrasive material is intentleci for use as a general purpose
20 abrasive product in the areas of ~;,.le~ , degl~ mlp7 repair, scuffing and
det~ rg in auLo.lluLi~e and general abrasive apr~ tione It is desired that the nonwoven
abrasive m~t~n~l provide the user a disposable abrasive product that is thin, useful and easy
to tliep~nee Further, the surface char~ neti~s ofthe nonwoven abrasive material are such
that when spiraUy wrapped in a roll, successive layers of the material illL~l ~llgage or adhere
together s~lffi~ ntly to . . .~ . the spiraUy wrapped roU configuration, but yet are readily
d - lV ~, ' le to permit unwinding of material from the roU, either from ~ c~nt an
innermost wrap or an outermost wrap. Further, the individual sheets 36 formed from such
nonwoven abrasive material have the ability to be folded or wadded into a desired shape by
a user, and wiU retain that shape without imm~i~t~.ly springing open. For example, FIG.4
illustrates a sheet 36 folded to a desired shape, and FIG.5 iUustrates a sheet 36 wadded or
crumpled upon itself. The inter~ng~ng surfaces ofthe sheet 36, as folded or wadded,
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WO 97/07937 PCT/US96/13941
tend to hold the formed shape rather than allowing the sheet to spring open to its more
fl~ttf~.n~-l, m~mlf~cl~lred state. This feature thus results in a very collrullllal)le or
"scrunchable" sheet 36 of nonwoven abrasive m~teri~l, which more closely imitates the feel
and look of a collrw'''able pad of steel wool.
There appear to be several factors involved that affect the 'lscr~ h~ yll of thesheet 36 formed of such nonwoven abrasive material. Th:~kn~e~ is the most obvious factor.
Prior art hand pads of nonwoven abrasive material, when folded or wadded, tended to
spring open because of their thi~l-n~ Weight is also a factor, since even a thin web will
want to remain ilat if it is a heavy web. Stiffness is also another trait that can be related to
10 ' ~ ' - and weight, but can also be a function ofthe materials of construction. Finally,
the self-Pn~ging surface ~ihal ~ilel i~Lic of the web is an illl~OI L~IL factor tending to hold the
web in a folded or wadded-up configuration, as illustrated in FIGS. 4 and 5. TheillLele~ging sl~rf~c~s catch or snag on one another to help hold the folds or creases in
place and overcome the resilient forces ofthe web material that tend to want to make the
15 sheet spring open to a more n~ d state. This feature also permits the user to define
other desired shapes. For; . '-, a sheet can be wadded or rolled into a pencil-shaped
configuration (with a tapered, cone-shaped end) which allows surface con~itionin~ in
otherwise in~ccP~ ,lc workpiece areas.
~ilG. 6 shows a roll 32 as plcr~l~Iy provided to the end user. ~Ith~ngh the
20 u..l~....t sl wrap of nonwoven abrasive material interengages with the next previous wrap
and is thus secured thereon, an outer pluLe~iLi~e sheath 50 is provided around the outermost
wrap ofthe roll 32. This sheath 50, which is ,~"~rt;l~ly formed from a polyethylene,
poly(vinyl chloride), or polyester shrink-wrap tubing as is well known in the art, with
poly(vinyl chloride) being more preferred, protects the outermost wrap, prevents the roll 32
25 from inadvertent unwrapping, and also provides a means for providing coll,mel~
;..r~ l;on and product idellLiryillg indicia 52. The shrink wrap sheath 50 comr~ y
covers the outermost wrap ofthe roll 32, but only partially covers its ends. The shrink
wrap sheath 50 is open (as at opening 54) ~ r~nt the central axis ofthe roll 32 (and its
opening 38) to permit di~pel~il-g of sheets 36 from the illll~l mo~L wrap of the roll 32
30 without removing the shrink wrap sheath 50.
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Other advantages from this invention are illustrated in the following c~ s,
which illustrate ~,. c;s~l.Lly contemrlated preferred embodiments and the best mode for
practicing the invention, but are not int~n-le(l to be limiting thereof.
EXAMPLES
Low density open, nonwoven abrasive material and methods for m~mlf~hlre
thereof are described in U. S. Patent 2,958,593. Alternative methods of p. e,o~u ...g
nonwoven abrasive m~f~.ri~l~ are available, and include carding, wet-lay, air-lay and
spunbond (as disclosed in U.S. Patent 4,227,350). Specific to one preferred embodirnent
of the present invention, a light-weight open, nonwoven air-laid web is formed on a
10 "Rando-Webber" m~hin~, co..~n.e.~;ally available from the Rando Machine Corporation of
Macedon, New York. The web is formed from 15 denier du Pont T852 ~. I. du Pont de
Nemours & Company, Seaford Plant, Seaford, Del&w~) a nylon crimp-set fiber with a
staple length of one and one-half inches. The weight of the fiber mat is a~ - . x;. ~ ly 15
grains per four inch by six inch sample (63 grams per square meter), and the thickness is
applvx;.~i.t~ly 0.200-0.250 inches (5.08-6.35 mm). The fiber mat is conveyed to a
hol- ~.o--Lal, two-roll coater, where a prebond resin is applied at a weight of 15-19 grains per
four by six inch sample (63-80 grams per square meter) wet. The prebond resin has the
following composition:
Coll.po~ ll Supplier Percentage
Neste BB-077 Phenolic Resin Neste Resins Canada, 74.9 %
M;~ ~..~ Ont~rio, Canada
Reactint Vlolet X80-LT Mil~iken Cl '~, 0.2 %
Rl-~ L~l,...~, SOU~ Carolina
Water 24.885 %
"1520" Silicone~ntifo~m DowCoî~ir~Cc.l~u.aliOl-, 0.015 %
Midland, Mic~igan
This resin has a percent solids of 52.5% and a viscosity of 100-200 centipoise.
Af'~er passing through the two-roll coater, the "wet" mat is conveyed to an ovenwhich is ~--~ cl at a t~lllpel~ re of 190-195 degrees Celsius to initiate curing ofthe
phenolic resin. Upon exiting the oven, the web is conveyed to a spray booth where a
resin/abrasive slurry is sprayed on the top portion ofthe web. Wlthin the booth, spray
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WO 97/07937 PCTAJS96/13941
nozzles (which are mounted to reciprocate pc~ .I;c~ rly to the direction of web
movement) apply the slurry at a weight of al,p, ws~~ tely 33 grains per four by six inch
sample (138 grams per square meter). The spray slurry has the following composition:
Composition Supplier Percentage
Neste BB-077 PhenolicNeste Resins Canada, 25.6 %
Mi~ ,...~ Ontario, Canada
Reactint Vlolet X80-LT Milliken Ch~ni~ 0.2 %
R~ , Sou~ Carolina
Water 16.1 %
Calcium Carbonate 4.2 %
~h-min-~m Oxide 53 9 %
(grade 280 and finer)
The slurry has a percent solids of 76.3 percent and a viscosity of 400-600 centipoise.
A~er spraying with this slurry, the web is conveyed to an oven which is . . .~ ;. .r~d
at a te~ )el~ re of 190-195 degrees Celsius to further cure the phenolic resin. Upon
exiting the oven, the web is inverted top to bottom and a spray coat is applied to the
underside ofthe web. This spray coat coln~osilion, application te~hniqu~ application
~mo -nt, and thermal processing are irlentic~l to the first spray coat. Upon exiting the final
oven, the cured web is wound on a winding mandrel to form a large jumbo roll of
nonwoven abrasive web material.
This jumbo roll is converted into finished product by first slitting the web into eight
inch wide master rolls which are then unwound, laterally cut and perforated. The pl ~rell ed
pe rol~llion blade is a four-tooth pe~rul~Llioll (four pclrul~lions per inch), with each
perforation cut being ~prJx;---~lely 0.200 inch (5.08 mm) long, with the cuts spaced apart
~plu~;lll; lely 0.040 inch (1.016 mm). Each pelrul~led unwound master roll is then cut to
a desired length and each cut length is rolled up for final p~ ~ng A shrink wrap or
shrink wrap tube is applied around each final product roll and processed to shrink firmly
around the roll, leaving holes of apl~l v,~ y four inches (10.16 cm) in ~lialn~ on the
top and bottom ofthe roll, arli~rrnt its central axis.
The final product is thus a shrink-wrapped, coreless roll of lofty, nonwoven
abrasive surface keated material. In a pl ~rt;l I ed embodiment, the roll width is eight inches
(20.32 cm) and its length (unwound) is twenty feet (6.096 m). The roll rl;i~ . (wound)
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is applu~ Lely nine inches (22.86 cm), and the center hole ofthe roll is app,u~il"~Lely
three inches (7.62 cm) in r~ PI . The web is laterally perforated every four inches
(10.16 cm), resulting in a total of 60 eight by four inch (20.32 cm by 10.16 cm) sheets of
nonwoven material per roll. The shrink wrap is formed from two to three mil, high clarity
S polyethylene shrink tubing, ~,e~ d with the desired commercial end product and source
irlPntifir ~tion il,ru""~Lion. The shrink wrap likewise has a center hole (pl GrGl ~Iy also
app, u~ L~ly four inch (10.16 cm) on both the top and bottom ofthe roll of nonwoven
abrasive m~tr~ri~l This roll size and p~r L-~ng thus results in a roll that is portable,
protected and self-co,.~ (or alternatively fits within most cu"""e~-;ially available, wall-
10 mount, center pull rli~ ir-. ~ (e.g., existing .~ .ce~ ~ for such products as paper towels
and wipes), although the center hole in the bottom of the di~,ellsel may need to be
e~ ed). The shrink wrap allows the roll of nonwoven material to be readily carried as an
individual, self-co. .l ~ d pa- ~ge of nonwoven abrasive material or dropped into such a
,G,~er without having to remove any of the roll's p~r L~ng m~tr~ri~l Altemative
15 p~ ~n~ and d;~GI~illg means will also suffice to ~ G"se sheets ofthe nonwovenabrasive m~tr~ri~l, such as a Z-fold dispG"ser, a stack of sheets or a cored roll of the material
with di~e,~i"g from the outemmost roll.
While a p, GrGI, Gd embodiment for the formation of a specific roll of nonwoven
abrasive m~tPri~l has been described above, other embo-limpntc are possible within the
20 scope of the present invention. For c,~"~lc, it is possible to have rolls with webs as short
as two feet (0.6096 m) or as long as 160 feet (48.768 m), with lateral widths of from one to
sixteen inches (2.54 to 40.64 cm). Roll .I;~ PI can be from two to twenty-four inches
(5.08 cm to 60.96 cm), with a central opening .1;,.., .~ c,~l ~. ..1;. .g from zero up to about
16 inches (40.64 cm). The pelrul~lions can be spaced Ir)ngiturlin~lly between a range of
25 one inch (2.54 cm) (to fomm short strips) or up to 24 inches (60.96 cm) (to prepare long,
foldable sheets of nonwoven abrasive material).
A preferred pG~ru~Lion ~I~.-g~ .I for this specific ~"ple is specified above.
This pel rul ~Lion ~ ge. . .~. .I was selected for the preferred embodiment based on an
analysis ofthe linear force required to separate ~ cPnt perforated sheets, using di~elGlll
30 pGlrul~Lion sçh~omPc Samples ofthe nonwoven abrasive material made as described above
CA 02229810 1998-02-17
WO 97/07937 PCT~US96/13941
-10-
were pc~ru~lcd using diLrclcll~ pwrul~ion blades, and then tensile tested to break the
pc~ru~Lions. Six dirrc-cllL blade configurations were c~;....;..ed in this regard:
1/8" x 1/16" Pc.ru-~lion - 1/8" cut, 1/16" no cut
1/16" x 1/16" Perforation- 1/16" cut, 1/16" no cut
4 Tooth Perforation - Four pc~ru-~lions per inch (appl.)x;ll~ eIy 0.200" wide) with
a no cut (~plo~ ,ly 0.040") se~ -g each pclrul~lion
6 Tooth P~ru-~Lion - Six pe~rO~lions per inch (approx;..,~l- .Iy 0.125" wide) with a
no cut (~ .x;..-A~ y 0.040") sep~li.-3 each pelrul~lion
8 Tooth Perforation - Eight pelrul~Lions per inch (applux;...~f ly 0.080" wide) with
a no cut (ap~loX;.. ~Iy 0.040") sep~Li lg each pelrul~Lion
10 Tooth Perforation - Ten perforations per inch (a,~,~lox;~ ly 0.060" wide) with
a no cut (ay~Jlu~ ly 0.040") se~ Li lg each p~,/rul~Lion
One inch wide strips ofthe above ~,~u--p'es of nonwoven abrasive material
(pc rul~ted laterally relative to web advance dun:ng web processing) were ~I~mped into a
CO~ rate of PYt~.n~ion tensile testing m~.~hinP; and evaluated using ASTM test method
16-82, the ~L~dald method for l"calci,-g load and ~Ion~tion oftextile fabrics usin~g the cut
strip option. Each strip was aligned with its pe.ru.~lion at its midpoint, and the force to
sc~ le the strip along its pc ru.~Lion was measured in pounds force, and the charac~f~ri.~ti~
force recorded was the peak load. As shown in the chart below, a number of sarnples for
each pe ru-~lion blade were tested:
Pc.ro.~Lion Blade Peak Load (Ib) Number of ,S~mptns Standard Deviation
1/8" x 1/16" 5.1 6 0.7
1/16"x 1/16" 7.2 7 1.1
4 Tooth 1.8 . 8 0.4
6 Tooth 2.9 8 0.2
8 Tooth 3.8 8 0.9
10 Tooth 4.3 8 0.6
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W O 97/07937 PCTAJS96/13941
As noted above, in the pl~rt;l IGd embodiment, the 4-tooth perforation blade wass~.lecte 1, which provided sl-ffif~i~nt strength to ~ Pn~ge the innermost wrap from the roll,
yet a11owed easy separation of ~ cP.nt sheets once two or more sheets were free from the
center hole of the roll.
S The above ~ "l~lc provides a nonwoven abrasive material formed in a two-roll
coater process, where a first coating serves to bond the web fibers togP,th~Q.r and a second
coating applies abrasive material to the web. Other coating m~thorl~ include roll coating
and spray coating of abrasive-bearing co~ lgs, inr~ tling coating directly onto the bare
fibers of the web, with no prebond coating. ~ ition~l Px~mples of nonwoven abrasive
material were formed using the roll coating compositions and coating processes as follows:
Co.. ~l.o~ Roll Coat Roll Coat Roll Coat Abrasive Abrasive Abrasive
#1 #2 #3 Roll CoatSpray CoatSpray Coat
#1 #1 #2
Water 42.9% 24.96% 26.2% 22.62% 17.46% 29.1%
Phenolic Resin56.7%74.64% 74.8% 22.62% 23.57% 29.4%
Sllrf~t~nt 0.2% 0.1% -- 0.11% -- --
FC-170CI
~Reactint" Violet 0.2% 0.3% -- 0.22% 0.2% --
X80LT2
calcium -- -- 3.88% 4.24% --
~bon~le
"Carbopol" -- -- -- 0.22% -- --
EZ-l
~ mimlm oxide -- - -- 5033% 54 53%
(grade 280
and finer)
~Q2~ ~ntifn~m4 o.o 15% --
silicon carbide -- -- -- -- -- 41.5%
(grade 1000
and finer)
a non-ionic n.. ~ r~l ~.. r.. ~.l available firom
Mi~m. $ol~ Mining and ~ -,...i"g Company, St. Paul, MN
2 dye,availablefiromMilliken('hPmi~llc slaeh~bu~ sc
3 available from B.F.~Joo~1ric~h Company, Cleveland, OH
15 4 available from Dow Corning Co., Miril~n~ Ml
The phenolic resin is a con-1en~te of a 1.96 to 1.0 formaldehyde to phenol ratio, with about
2% potassium hydroxide. It is a 70% solids solution, with 25-28% water and 3-5%
propylene glycol ether. Using these compositions, a number of samples of nonwoven
20 abrasive material were formed with the paJ~UI~ set forth in Table 1 below:
CA 02229810 1998-02-17
WO 97/07937 PCT~US96/13941
~ ~'~ C , o 'D ,~
.~ ~ ~I _ I _ I _ _ _ _ I I ~
V
o
.
V _I _ I _ I I : _ _ I
o
D D D D C C .~; D C
C;~ ~ Z ~ O ~ O O
v ~ v ~ V
~ ~ O ~ ~ ~ V~ ~ ~ ~ _ ~
~ a: v a ~ ~ c~
V~
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The references in Table 1 to fiber type and size are more specifically detailed as:
6 d. nylon is six denier du Pont P-113, available from E. I. du Pont de Nemours &
Company, Seaford Plant, Seaford, Delaware;
15 d. nylon is 15 denier du Pont T-852, available from E. I. du Pont de Nemours &
Company, Seaford Plant, Seaford, Delaware;
4 d. "Celbond" is four denier thermaUy bondable fiber available from Hoechst-
Celanese, of Charlotte, North Carolina; and
15 d. "Celbond" is 15 denierthermallybondablefiberavailablefromHoechst-
Celanese, of Charlotte, North Carolina.
In Table 1, "Prebond Method" refers to three options: phenolic, thermally
bondable fiber or none. The "phenolic" p.~ond method inr.llld~c a resin roll coat step to
bond the loose web fibers tog~th~or~ with an oven cure at 190-195 degrees Celsius. The
"thermally bondable fiber" prebond method in~ ld~s no resin coating, but rather simply an
oven heating ofthe web to bond the loose fibers together, again at 190-195 degrees
20 Celsius. The "none" prebond method in~l~ldes no specific step to bond the loose web fibers
together, but rather doing so in the course of applying the abrasive coating, via roll coating
or spray coating.
In ~d~ition to specifying which sample (e.g., samples A-L) were formed from
which m~tt~.ri~l, and subjected to which prebond, Table 1 also specifies the nature ofthe
25 coating and their respective dry weights added to each sample by each of the coa~
Two testing s(~h~ s were devised in order to measure the .stiffn~cc and self-
g nature ofthe nonwoven abrasive material samples A to L and to CO~ )~c; those
samples to prior art nonwoven abrasive materials. The stiffness of the samples and prior art
k~ was d~lel ll~ined by a three-point flex test based on the procedures described in
30 ASTM Test Method D 790, "Standard Test Method for Flexural Properties of
Ulll~r~ed and Reil~lced Plastics and Electrical Tn.~ ting materials." Five 1 inch by
6 inch (2.54 cm x 15.24 cm) spe~im~nC were cut from each example web. The average
t1 :~~nPcc for each c,~ullplc was determined by m~cllring a stack of five sperimPne Test
~,l,e~ n~ were mounted in a three-point fixture having contact points conl,.,li.,illg 1/8 inch
(0.32 cm) ~ .ol dowels ~ -g 1 inch (2.54 cm), the fixture being mt-l-nted in a
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-14-
co~ rate of extension tensile testing machine. The test was initiated and the crosshead
moved at 1 inch (2.54 cm) per minute to an initial limit of 2% strain. The force was then
tared and the test continued to a final limit of 5% strain. The bending force in grams at 5%
strain was recorded.
S The self-~n~ging phenol,lellon was measured by ovt;ll~pill~ two one by five inch
(2.54 cm by 12.70 cm) strips of each ofthe nonwoven abrasive material samples and prior
art end to end with a two inch (5.08 cm) overlap. The ovella~l)ed strips were then placed
on a ~,ibl~Lc ly feed motor with a one pound weight on top ofthe overlap. The vibratory
motor was a Syntron Magnetic Feeder, Model F-TOC, controlled by a Syntron Electric
Controller, Model CSCR-lB, both available from FMC Corporation's Material H~n-lling
Fqllirm~ont Division, Homer City, Pennsylvania. The motor was run for 15 seconds at a
controller setting of six. The weight was then removed and a paper support was wl~ed
around the overlapped area to prevent movement during Ll ~JOl L and securing in a tensile
test fixture. The ends of the strip were ~ .ed into a col~L~l~ rate of ~ n tensile
testing m~rhin-~; and evaluated using ASTM Test Method 16-82, the standard method for
breaking load and elongation of textile fabrics using the cut strip option. The force to pull
the two strips apart was measured in grams force, and the characteristic force recorded was
the peak load.
Table 2 below pl esc;l.L~ the average measured values for the samples, both for
samples A to L, and for five prior art nonwoven abrasive materials. To incol ~Ol ~e
thi~kn~cc and weight into the analysis, the required bending force was divided by the
density of the nonwoven abrasive materials being tested. This conll.illes the properties of
thieL-n~cc, weight and stiffness into one variable.
The five prior art nonwoven abrasive n~.telials considered in these tests include
three products from Mil~lesoLa Mining and Ml~m If ~lrjng sold under the ~e~ci~tion
"SCOTCH-BRlTE." These three products are also further identified by product Nos. 96,
7447, and 7448. In Table 2, these products are id~ntified as 3M-96, 3M-7447 and 3M-
7448, respectively. Another prior art nonwoven abrasive material considered is
m~mlf~hlred by Mirka of Finland, and is identified cOllllllc;l .,;ally as Mirka "MIRLON"
surface finiching pad 18-111 447, grit very fine. In Table 2, this product is id~ntified as
Mirka 447. The other prior art nonwoven abrasive material considered is m~mlf~ lred by
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Norton of Wolce~Le~ c~ch~lsett~ This product is identified collul~ ;;dlly as Norton
"BEAR-TEX" No 747 general purpose hand pad, grit very fine. In Table 2, this product is
.nfified as Norton-747.
The measurement of the self-Pn~n~ nature of the nonwoven abrasive material
S involved a more subjective analysis. In Table 2, the column labeled "Self-F,nf~ging"
p, ~se,l~ the results of a subjective test pel r~l Illed by wadding a sheet of the nonwoven
abrasive web into a ball, and observing whether the web recovers to its original shape or
remains wadded up. Samples labeled "YES" rP.m~ined wadded up and were thus
considered to be self-t~.n~gin~
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~ ~ ''~ oo ~ oo ~ ~ oO ~ oo -- ~ o ~ ~ o ~ ~
~ ~ ~0 ~ ~ ~ ~ ~ O' ~ 00 ~ ~ ~ ~ ~ ~
~o
'~
~ o o o o o O ~ ~ ~ ~V ~V ~ ~ C.~ ~ ~ ~
Z ~ Z; Z Z ~Z; Z Z Z ~ ~ ~
~.q
~ a~
O o _~
~ o ~r ~ 00 0~o - , ~ ~ ~O ~ o o
~ m
P
V~
a~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
U~
a~ ~ ~ O O O O ~ O O 00 o o o o v. o ~ o
-,~ ._ O O O O O O O O O O O O O O O O O
~ 1-- ~ o ¢ ~ ~ ~ ~ ~ ~ ~
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A scratch test provides a means of comparing the surface finish imparted to a
workpiece by the action of an abrasive article. The test workpiece is a 15 inch x 15
inch x 0.25 inch thick (38.1 cm x 38.1 cm x 0.64 cm) acrylic sheet. A number of 2
inch by 4.25 inch (5.1 cm by 10.8 cm) specimens are cut from the abrasive materials to
5 be tested and placed in contact with the acrylic sheet. The acrylic sheet is labeled to
identify each test speçimen A 2 inch by 4.25 inch (5.1 cm by 10.8 cm) weighted
sanding block weighing 8.32 Ibs (3.74 kg) is then placed across the test specimens such
that the test speçim-?n~ are COIllpl essed against the workpiece. The sanding block is
then linearly reciprocated across the 15-inch (38.1 cm) dimension of the acrylic sheet.
10 Following 50 full cycles of abrading in this manner, the sanding block and test
specimens are removed from the acrylic sheet, the sheet is cleaned with window
cleaning solution and a paper towel, and surface finish is measured in a direction
perpendicular to the direction of the abrasion at 4 equally-spaced places along the
abraded length of the abraded track . The surface finish is measured using a "Perthen
S6P" No. 680 0602 profilometer, available collllllel~;ially from Feinpruf GmbH,
Gottingen, Germany. This device is capable of measuring and calc~ ting many surface
profile pal ~ eLers, but for the purposes of this test, the parameters Average
Roughn.Qs.s (Ra) and Bearing Ratio are recorded. The Average Ro~ghn~s.s is the
arithmetic average of the depth of all sequential peak-to-valley scratches imparted to
the surface along a test path and is measured in microinches. Values of Ra generally
vary with the grade of abrasive particles present in the abrasive article. The Bearing
Ratio is a measurement by which one can loY~mine im~gin~ry "slices" or planes parallel
to the abraded surface as they move deeper into the abraded surface and is expressed
as a fraction (or percentage) of the abraded surface that would be a "bearing" surface if
the im~gin~ry slice were being supported at that distance from the surface of a test
path. Such me&sulelll~llls provide a means for detelll~il~ng the UllirOlll~iLy of abrasion
imparted by the test specimen and the shape ofthe rçslllting scratches. In practice, a
l erel ence point is chosen and the Bearing Ratio is calculated as the plane is
inc~ lly moved deeper into the abraded substrate until it has progressed throughthe abraded s--rf~e7 thereby generating a Bearing Ratio value of 1 (or 100%). For
colll~ e purposes, Bearing Ratio values at a test "slice" at a con~Lalll distance
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from the reference point are reported. For abrasive articles useful in the pl~pa.~Lion of
automotive finishes for subsequent coatings, an abraded surface Bearing Ratio ofapploxi,..a~ely 15-60% is p~t;r~"~d, with a value of approximately 15-50% being more
pl ere" c~d, and a value of apl)rox"lla~ely 15-40% being still more pl erel I t;d.
S In addition to the Bending Force and F.ng~gçment Force tests reported with
respect to examples A-L above, the surface finish imparted by the abrasive sheet of
Ex~llplc L was conlpal ed to that of commercially available abrasive articles byp~l r~ "g the Scratch Test using a Bearing Ratio reference plane of 5% = O ~Lm; that
is, a depth of 5% of the average scratch depth is re-defined as a reference plane of
0.0 micrometers depth. The Bearing Ratio is reported at the plane that is at a depth of
0.3 micrometers relative to the 0.0 reference plane. The values reported in Table 3 are
the average of specimen top and bottom sides. Ra is reported in microinches and
Bearing Ratio is reported in percent. The data in Table 3 show that the sheet ofExample L produces a surface finish that is fine (Ra < 10 microinches) and very
uniform without jagged scratches (Bearing Ratio C 50%)
,_ ~
-
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-19-
TABLE 3
Weight Thi~l~nPcc Ra ~L~-da--l Bearing
Fxs~mrle (grains/24in2 (mils R~deviationRatio (~ 0.3
(grams/m2)) (mm)) mi-;.o.l.~;L~-~
Type S5 117 (491) 345 (8.76) 8.490.32 40.8
Type S5 113 (475) 412 (10.5) 3.280.32 91.8
Type S, (FR)6 94 (395) 371 (9.42) 5.280.81 73.9
Standard7 125 (525) 400 (10.2) 6.100.55 66.5
Norton8 140 (588) 492 (12.5) 3.420.66 88.6
Mirka UK9 88 (370) 360 (9.14) 9.770.40 33.6
Sia'~ 83 (349) 401 (10.2) 11.930.82 24
Mirka" 97 (407) 400 (10.2) 9.600.64 32.6
Steel Wool #2 - - 14.9
Steel Wool #0 - - 12.3
Steel Wool #00 - 7.1
Steel Wool #0000 - - 7.1 - 53.5
F.Y~mp'c L 49 (206) 295 (7.49) 9.250.44 35.6
FY~mrl~ L 65 (273) 312 (7.92) 9.160.66 40 8
Fx~mple L 52 (218) 266 (6.76) 9.700.62 34.8
FY~mrle L 54 (227) 248 (6.30) 8.880.66 35.5
5 "Type S Ultra Fine", Mi~ ul~ Mining and I~ r~ .E Company, St. Paul. MN
6"3M 7448",3M France, Paris, France
"'Brite Rite EZ Ultra Fine", Standard Abrasives, Chdl~wul Ll., CA
8 ~'Norton Bear Tex 748", Norton Abrasive Company, Worcester, MA
9 "Mirka Ultrafine Hand Pad 18-111-448", Mirka Abrasives, London, England
"Sia Strips Ultra Fine No. 9173", Sia ~m~:nr~n, Lenoir, NC
Il ~'Mirka Merlon Surface Finishing Pad UF~, No. 18-111-448, Mirka Abrasives, Twi~ g, OH
As ~--c ~Lioned above, the self f.. ~,;.gi.~g nature or "scrunchability" ofthe nonwoven
abrasive material adds a unique feature to the end product. A roll of this matenal is wound
and the end of the outermost wrap simply pressed against the previous wrap to ~ i. l a
self-~-lh~.ring wrap of nonwoven abrasive material about the roll. No tape, adhesive or
~~e~ 1 r~cllcl~ are required to secure the successive wraps of nonwoven abrasive- 15 material togf~tht-r. Thus, the product is ~c~-.nti~lly self-pa~k~ng The ~ ition ofthe
shnnk wrap sheath is simply to increase durability, keep the product clean and provide a
~ 1lll for product identification.
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In a preferred embodiment7 the nonwoven abrasive material is perforated to create
a wP~kPnP,d area across the material for sepdl ~Ling ~ Pnt sheets of the material from the
roll. Any type of meçh~n: ,~1 p~.r.~l~lion method is applicable7 in~ ing water jet
perforation and " ,P. -I IAI ~ blade perforation. I.llpal ling a high degree stretch at specific
5 points in the web, specific ~li~mPnt ofthe fibers and various web formation methods can
also create wP~kPned areas across the web that could be used to enhance the separation or
tear of ~ P.nt sheets. In web formation, an air knife could be used to alter the web
illlegliLy in a line across the web for tearing purposes.
In the plt;r~lled embodiment ofthe present invention7 the desired objective during
10 the ~ g operation is that all sheets remain conti~lously ~tt~c~hed until the innermost
wrap (colllp[ising one free end and at least two sheets with in~ ded perforations) is
c(JI~ tPly freed from the roll's center hole. Once the innermost wrap is free from the
center hole of the roll (and end opening of optional pl~ Le.;li~e sheath), it is then that an
appli~tion of ill~;l r;l "," ,1 ~lly g7reater force may be applied to sep~ ~e the end sheet from its
15 ~djacPnt sheet along the pelrul,llion therebetween. It is illl~OI L~UIL that the force required to
separate ~ a~pnt sheets be appl ~ e for the nonwoven abrasive material involved. The
perforation strength (i.e., the force required to s~,ua-~e a~ pnt sheets such as exerted
along arrow 48 in FIG. 3) requil ~ ellL~, vary d~;p~ g on the various embodiments of the
article ofthe present invention. Generally, the pelr,l~lion strength must be g7reater than the
20 illLel ~. ~qgPtnPnt strength7 but less than the tensile or shear strength of the abrasive material
itself. For ~ .lr; abrasive sheets with high ill~ ging capacity will require a greater
pelr~ -~lion strength in order to avoid premature sepd,dlion ofthe sheets when di~pt;l.sed
from the center hole of the roll. Likewise, a wider roll will require a greater perforation
strength since more ill~ g~g~ must be overcome. Further, the roll center hole
25 internal ~ ...e~ (i.d.) affects the pe-ru~lion strength requl.clll~ s since, as the i.d.
beco...es larger, the sheets are more easily .1;~ "~1 and thus the pe ru.~ion strength may
be dec.~sed. Obviously, during the consumption of the roll of abrasive material, as more
sheets are di~pe sed from the roll, the p~lr~ ion strength requilGIn~ become less as the
i.d. ofthe center hole beco...es larger. Similarly, if the end opening ofthe pl~lec~h~e sheath
is small in ~ .e., Iess than about 3 inches (7.62 cm)), the p~lr~ lion strength
CA 02229810 1998-02-17
W O 97/07937 PCTAUS96/13941
requirement is higher than if the opening is relatively large (i.e., about 5 inches (12.7 cm) or
more).
In ~mr'~- A-K detailed above, the abrasives specifed are relatively aggressive
abrasives. An ~p~ u~ le abrasive characteristic for the nonwoven material would be
5 selected by a person of ordinary skill in the art, depending upon the workpiece and desired
surface Ll 5;i. 1. . .~. ,I Thus, aggl e~ive is a relative term dependent on these factors. It is
understood that any abrasive, inr.l~lrling a soft abrasive, a hard abrasive, or a mixture
thereof, will suffice in connection with a nonwoven material to create a nonwoven abrasive
web having the inventive characteristics. Soft abrasives, having a Mohs hald"ess in the
10 range of about 1 to 7, provide the nonwoven web material with a mildly abrasive surface.
Fx~mr'-r of soft abrasives include such inol~,al~ic materials as garnet, flint, silica, pumice,
and calcium c~bol-~Le; and such organic polymeric material as polyester, poly(vinyl
chloride), poly(m~l1laclylic acid), poly(~ LllyL..~ rrylate, poly-,~uboll~le, polystyrene, and
particles of Illc;lmos~;LLillg polymers such as .... ~ o-formaldehyde con~n~tes Hard
abrasives, those having a Mohs hdl dne:js greater than about 8, provide the nonwoven web
material with an aggressive abrasive surface. _xamples of hard abrasives include such
materials as silicon carbine, ~I.Imimlm oxide, topaz, fused alumina-zirconia, boron nitride,
hlr~.n carbide, and silicon nitride. The particle size ofthe abrasive material can be any
desired size, but typical sizes are from about 80 grade (average dia.ll~Lel approx. 200
miclo",~Ltl~) to about 1000 grade (average ~ approx. 3 ~uclc~llleLt;~) or finer.It is also within the scope of the present invention to use even finer abrasive
particles, as detailed with respect to; , Ic L. Abrasive particles of 1000 grade and finer
are useful for illlp~ Lulg fine surface finish as measured by both Ra and Bearing Ratio. Such
an article can be constructed, for ~ mpl~, with an abrasive particle and binder mixture in
which the abrasive particles c~ e ~vro~ull~Lely 40-80%, plert;lal~ly appl~xull~Lt;ly
66%, by dry weight of the binder and particle mixture, with an abrasive particle and binder
mrxture dry add-on weight of apploxullaLely 15-50 grains per 24 in2 (63-210 grams/m2) and
pl~re;l~ly a~ ;",~ ly 25 grains per 24 in2 (105 grams/m2). It is seen from the data
pl t;~t;llled in Table 3 that such nonwoven abrasive material can provide a surface finish
col,lpcu~le to that of#00 and #0000 steel wool. Such an abrasive particle size can
ad~,~"l~geu,-.~ly be used with the "SCr~nr'~~t-'e" nonwoven material described above, and
-
CA 022298l0 l998-02-l7
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-22-
can also be adv~nt~g~ollely used in other, "non-scrunchable" nonwoven m~t~ri~l Particle
size distribution was measured with a Coulter ~l~hiei7to.r II, available from Coulter
Electronics, T imite~ Bedford, Fngl~ntl Particle size distributions (si_e reported in
micrometers) of two batches of abrasive material suitable for use with the 1000 ~de and
S finer embodiment are, t;pul led in Table 4 as volume percent. It is understood that this is
reported by way of ~mple only, and that the 1000 grade and finer embodiment ofthe
present invention is not lirnited to the particular abrasive particle size distribution of
Example L.
TABLE 4
Batch 3% 5% 50% 90% 95%
1 > 11.45 > 10.32 > 4.72 >2.26 > 1.88
2 > 14.72 > 13.8 > 6.8 >2.6 > 2.0
The nonwoven material itself (a nonwoven three-~lim~n.cional lofty web of crimped
or lm~ ted synthetic fibers which are adhesively bonded at points of mutual contact with
a binder material), without a specific coating of "abrasive" particles, may have the desired
abrasive characteristics. Again, this is dependent upon the nature ofthe ~hulkr ~ce and the
intPn-led surface Ll~.LI-w -l for that v~u-
~
Although the present invention has been described with ~c~r~nce to preferredembo-1imrnte wo-kel~ skilled in the art will recogni7ç that changes may be made in form
and detail without departing from the spirit and scope ofthe invention.
