Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~070138
DISPENSING CONTAINER HAVING SMOOTH NONABRASIVE
ANTISLIP COATING ON THE BOl~OM SURFACE THEREOF
Cross-Reference to Related Application
s
The smooth nonabrasive antislip coating utilized in the present
invention is described and claimed in copending and commonly assigned
Application Serial No. , entitled SUBSTRATE HAVING A
SMOOTH NONABRASIVE ANTISLIP COATING and filed of even date
10 in the names of Frances Joseph Kronzer, Theodore John Tyner, and John
Patrick Allison.
Background of the Invention
The present invention relates to a dispensing container having a
smooth nonabrasive antislip coating on the bottom surface thereof. The
antislip property of the coating is obtained through incorporation in the
coating binder of thermally expandable microbeads.
Antislip or non-skid coatings are, of course known. For example,
20 non-skid surface compositions for paper products are disclosed in U.S.
Patent No. 4,418,111 to Carstens. The composition consists of an aqueous
suspension of colloidal silica and urea. The silica typically is present at a
level of from approximately 1 to 5 percent by weight and has particle sizes
in the range of 10 to 150 millimicrons. A urea/silica weight ratio between
0.10 a~d slightly greater than 3.00 is most effective. The composition is
applied to the paper product by, for example, spraying.
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An antiskid paper with enhanced friction retention is described in
U.S. Patent No. 4,980,024 to Payne et al. According to this reference,
superiority in retained slide angle of antiskid paper is achieved by spraying
or otherwise coating the paper with a composition of matter consisting
S essentially of silica sol, glycerine, and an acrylamide homopolymer.
As illustrated by the foregoing two patents, antislip coatings for
papers typically employ an inorganic material in the coating binder. Such
coatings often are abrasive and, in fact, are closely related to such abrasive
papers as sandpapers, emery cloths, and the like, as illustrated by the
10 references which follow.
U.S. Patent No. 2,899,288 to Barclay relates to a method of forming
an abrasive sheet. Briefly, a cloth backing sheet fabricated of a thermo-
plastic material is passed through a heated zone in which one face of the
sheet is temporarily softened, an abrasiYe material is applied evenly over
15 the softened face, the abrasive is pressed into the softened sheet by means
of a nip roil and simultaneously cooled.
U.S. Patent No. 3,166,388 to Riegger et al. relates to a sandpaper.
The sandpaper comprises a reinforced paper backing, a barrier material, a
layer of making varnish, and a layer of abrasive grits embedded in the
20 making varnish. The barrier material may be in the form of a barrier layer
of flexible material which only partly penetrates into one side of the
backing, or it may be in the form of flexible rubbery solids which penetrate
into and partially fill th~ voids in the paper backing throughout its
thickness. Backings comprise a web or network of wood pulp fibers and
25 a multiplicity of relatively flexible and tough thermoplastic reinforcing
members distributed substantially throughout the web in bonding relation
with the wood pulp fibers.
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The commercial introduction of thermally expandable microspheres
a number of years ago has led to a number of different uses, some
examples of which are given below.
U.S. Patent No. 4,006,273 relates to washable and dry-cleanable
S raised printing on fabrics. Raised prints and graphic designs on fabrics
which can safely and effectively be dry-cleaned and washed are provided
by formulating a cross-linkable polymer printing medium comprising an
adherent film-forming cross-linkable polymer binder in a liquid vehicle
therefor about 1 to 45 weight percent thermally expandable microspheres,
10 based on the weight of the binder, applying said medium to a fabric,
heating at a temperature of about 180 to 250F to expand the micro-
spheres and cross-link the polymer, and then curing for about 1 minute at
a temperature of about 300F. The microspheres can have diameters from
about 0.5 to about 300 microns (micrometers or ~m), preferably from
about 3 to 50 microns, and most preferably from about 5 to 20 microns.
U.S. Patent No. 4,044,176 to Wolinski et al. describes graphic arts
media which offer raised, three-dimensional effects. A basic medium is
formulated of a colorant, film-forming binder, a solvent vehicle, and
thermally expandable microspheres. The microspheres are treated to
preclude or inhibit solvation in the solvent vehicle by coating with a
compound which is a non-solvent for the microspheres but which preferen-
tially wets the surface thereof. Allyl alcohols having about 3 to 5 carbon
atoms in the allcyl chain are employed. The medium is selectively applied
to a substrate, dried, and heated to expand the microspheres.
Japanese Published ~pplication No. 90/76,735 relates to the
manufacture of slightly rough sheets. Such sheets, useful as wall and floor
coverings, leather substitutes, packaging sheets, etc., are prepared by
2070138
coating thermoplastic sheets, completely or in patterns, with resins
containing microencapsulated blowing agents (e.g.~ butane) and simultan-
eously expanding the microcapsules and softening the resins. In an
example, flame-retardant paper was coated in patterns with an acrylic
polymer-PVC blend containing microencapsulated blowing agents, coated
with a PVC plastisol, and heated at 225 to give a sheet with a sandy
appearance.
It may be noted that microspheres which are not thermally expand-
able also are known. A few applications for such microspheres are
described below.
A woven polyester-backed flexible coated abrasive having microbal-
loons in the backsize is described in U.S. Patent No. 4,111,667 to Adams.
The backsize is used with heavy-duty flexible coated products, particularly
polyester-backed coated abrasive for use in making belts. The otherwise
conventional backsize coating includes from 2 to 10 percent by weight of
hollow microspheres. The coating is applied on the reverse or nonabrasive
side of a woven polyester backing. The microspheres (or microbeads or
microballoons) are hollow spheres of resin or glass having a diameter in the
range of between 5 and 125 microns (micrometers).
U.S. Patent No. 4,543,106 to Parekh relates to a coated abrasive
product containing hollow microspheres beneath the abrasive grain. The
product comprises a fabric backing~ a layer of abrasive grain, and at least
one layer of resin between the backing and the abrasive grain. Hollow
microspheres are present and at least partly and usually entirely embedded
in the resin layer. In general, the hollow microspheres comprise hollow
spherical bodies which may be of glass or plastic materials such as a
phenolic resin, which have diameters from about S to about 500 microns
- 4 -
2070138
(micrometers) and an average diameter of from about 25 to about 125
microns. The microspheres generally have a shell thickness which averages
from about 5 to about 20 percent of the diameter of the microspheres. The
microspheres usually are incorporated into the resin layer in an amount of
5 from about 5 to about 20 percent by weight of the resin layer.
A reference which does not fit in any of the foregoing categories is
included for the sake of completeness. That reference is U.S. Patent No.
5,001,106 to Egashira et al., which relates to an image-receiving sheet.
Such sheet comprises a base sheet and a receiving layer, provided on one
10 surface of the base sheet, for receiving a dye or pigment migrating from
a heat transfer sheet. The base sheet comprises one or two or more layers,
with at least one layer having a porous or foamed structure. A layer
having a porous or foamed structure can be obtained by such methods as:
(a) stretching a film prepared from a thermoplastic resin and containing fine
15 inorganic or organic particles, (b) extruding an organic solvent solution of
a synthetic resin into a coagulating bath, and (c) extruding a resin together
with a foaming agent. Under certain circumstances, it is desireable to
roughen at least a part of both front and back surfaces of the image-
receiving sheet, e.g., the non-image portion of the receiving surface or the
20 back surface of the image-receiving sheet, by imparting fine unevenness
thereto.
References relating to the microbeads themselves include those
described below.
U.S. Patent No. 3,615,972 to Morehouse, Jr. et al. describes
25 expansible thermoplastic polymer particles containing volatile fluid foaming
agent and a method of foaming the same. Thermoplastic microspheres are
prepared which encapsulate a liquid blowing agent. Heating of the
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microspheres causes expansion. The microspheres are useful for coatings,
moldings, plastic smoke9 etc.
Polymer foam compositions are described in U.S. Patent No.
3,864,181 to Wolinski et al. The patent describes a composition and
5 method for forming foamed polymers. The composition comprises a
dispersion of microspheres in a solution of the polymer in a solvent. The
compositions are applied to a substrate, dried, and heated to expand the
microspheres, thus forming a foamed polymer. The particular surface
characteristics of foamed polymers are stated to have been utilized in non-
10 skid coatings for carpets, rugs, bathtub mats, flooring, coat hangers,handles for tools and athletic equipment, and the like.
U.S. Patent No. 4,722,943 to Melber et al. relates to a composition
and process for drying and expanding microspheres. Microsphere wet cake
is mixed with a processing aid effective to prevent agglomeration and
15 surface bonding of the microspheres, and thereafter removing water by
drying with continuous mixing, optionally also under reduced pressure,
i.e., vacuum drying. By the control of the application of heat and
balancing temperature and the mixing, and optionally also the reduced
pressure, it is possible to also control expansion of the microspheres from
20 substantially none to substantially theoretical limits of expansion. Suitable processing aids include, by way of example, dry inorganic pigments or
filler materials and the like, and related organic materials. See also U.S.
Patent Nos. 4,829,094 to Melber et al. and 4,843,104 to Melber et al.
2070138
Summary of the Invention
It therefore is an object of the present invention to provide a
dispensing container having a smooth nonabrasive antislip coating on part
5or all of the bottom surface thereof.
This and other objects will be apparent to one having ordinary skill
in the art from a consideration of the specification and claims which follow.
Accordingly, the present invention provides a dispensing container
having a smooth nonabrasive antislip coating on part or all of the bottom
10surface thereof, which coating:
A. is comprised of from about 80 to about 99 percent by
weight, based on the weight of the coating, of a binder
having a glass transition temperature no lower than about
-30C and from about 1 to about 20 percent by weight,
15based on the weight of the coating, of thermally expanded
microbeads having particle sizes before expansion in the
range of from about 5 to about 30 ~m;
B. has a dry static coefficient of friction, when tested in
accordance with ASTM method 1894 against an alumi-
20num plate having an anodized surface with a roughness
of less than about 0.8 ~m, of at least about 0.6; and
C. has a dry dynamic coefficient of ~riction, when tested in
accordance with ASTM method 1894 against an alumi-
num plate having an anodized surface with a roughness
25of less than about 0.8 ~m, of at least about 0.8.
The unique smooth and nonabrasive coating employed in the present
invention permits placing the containers on any surface, including furniture.
2070138
Detailed Description of the In~rention
As use herein, the term "smooth" refers to the absence of sharp or
angular particles in the nonabrasive antislip coating utilized in the present
S invention. Rather, such coating contains smooth, e.g., spherical, micro-
spheres. The term also refers to the feel of the surface when touched, i.e.,
to the tactile characteristics of the coating. That is, the coating feels
"smooth" to the touch.
The term "dispensing container" is meant to include any dispensing
10 container which is intended to be placed on an essentially horizontal surfaceand remain essentially portable or moveable. Thus, the term excludes wall-
mounted containers and any other dispensing containers which are mounted
or otherwise fixed in a stationary position. The dispensing container most
often will be a free-standing tissue or wipe dispenser.
The term "bottom surface" refers to the bottom, external surface of
the dispensing container, i.e., the surface of the dispensing container which
comes in contact with the surface upon which the dispensing container is
placed.
The material from which the dispensing container is made is not
20 known to be critical. As a practical matter, however, the container most
often will be constructed from a cellulosic material, such as paper or
cardboard.
The smooth nonabrasive antislip coating can be applied directly to the
bottom surface of the dispensing container either during or after its
25 manufacture. Alte~natively, the coating can be applied to the first surface
of a paper substrate having a contact adhesive protected by a release paper
on the second surface. In this case, the coated paper can be applied to the
2070138
dispensing container as part of the manufacturing process or by the
consumer. Because a coated paper is more easily tested, such a paper was
the focus of the work described hereinafter.
The percentage of the bottom surface to be coated is not known to
5 be critical. Of course, the maximum antislip effect will be achieved when
all of the bottom surface is coated. Coating only part of the bottom surface
in many cases will give adequate antislip characteristics to the container,
especially when heavier containers are involved. Conversely, small
containers which generally are lighter preferably will have coating on the
10 entire bottom surface.
When the coating is applied to a cellulosic sheet, the nature of the
cellulosic sheet is not kI~Owh to be critical, provided it has sufficient
strength for handling, coating, sheeting, and/or other operations associated
with its manufacture. In preferred embodiments, the sheet will b~ a latex-
15 impregnated paper. By way of illustration, a preferred paper is a waterleaf sheet of wood pulp fibers impregnated with a reactive acrylic polymer
latex such as Rhoplex0 B-15 (Rohm and Haas Company, Philadelphia,
Penrlsylvania). However, ~ny of a number of other latexes can be used,
if desired, some examples of which are summarized in Table I, below.
Table I
Suitable Latexes for Base Sheet
Polymer Tvpe Product Identification
Polyacrylates Hycar0 26083, 26Q84, 26120,
261~)4, 26106, 26322
B. F. Goodrich Company
Cleveland, Ohio
2070138
Rhoplex0 HA-8, HA-12, NW-1715
Rohm and Haas Company
Philadelphia, Pennsylvania
Carboset0 XL-52
B. F. Goodrich Company
Cleveland, Ohio
Styrene-butadiene copolymers Butofan0 4262
BASF Corporation
Sarnia, Ontario, Canada
DL-219, DL-283
Dow Chemical Company
Midland, Michigan
Ethylene-vinyl acetate copolymers Dur-O-Set0 E-666, E-646, E-669
National Starch & Chemical Co.
Bridgewater, New Jersey
Nitrile rubbers Hycar0 1572, 1577, 1570 x 55
B. F. Goodrich Company
Cleveland, Ohio
Poly~vinyl chloride) Geon0 552
B. F. Goodrich Company
Cleveland, Ohio
Poly(vinyl acetate) Vinac0 XX-210
Air Products and Chemicals, Inc.
Napierville, Illinois
Ethylene-acrylate copolymers Michem0 Prime 4990
Michelman, Inc.
Cincinnati, Ohio
Adcote0 56220
Morton Thiokol, Inc.
Chicago, Illinois
- 10 -
207013~
The impregnating dispersion typically also will contain clay and a
delustrant such as titanium dioxide. Typical amounts of these two materials
are 16 parts and 4 parts, respectively, per 100 parts of polymer on a dry
weight basis. An especially preferred paper has a basis weight of 13.3
lbs/1300 ft2 (50 g/m2) before impregnation. The impregnated paper
preferably contains 18 parts impregnating solids per 100 parts fiber by
weight, and has a basis weight of 15.6 lbs/1300 ft2 (58 g/m2), both on a
dry weight basis. A suitable caliper is 3.8 mils + 0.3 mil (97 + 8 micro-
meters).
Such a paper is readily prepared by methods which are well known
to those having ordinary skill in the art. In addition, paper-impregnating
techniques also are well known to those having ordinary skill in the art.
Typically, a paper is exposed to an excess of impregnating dispersion, run
through a nip, and dried.
- 15 Turning now to the smooth antislip coating, such coating, regardless
of the substrate, is comprised of from about 80 to about 99 percent by dry
weight, based on the dry weight of the coating, of a binder having a glass
transition temperature no lower than about -30C and from about 1 to
about 20 percent by dry weight, based on the dry weight of the coating, of
thermally expanded microbeads having particle sizes before expansion in
the range of from about 5 to about 30 ~m. In addition, such coating must
have a dry static coefficient of friction, when tested in accordance with
ASTM Method 1894 against an aluminum plate having an anodized surface
with a roughness of less than about 32 microinches (about 0.8 ~m), of at
least about 0.6, and a dry dynamic coefficient of friction, when similarly
tested7 of at least about 0.8.
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Generally, the binder can be any of the known binders which
commonly are used as the basis of coatings on paper and other substrates,
provided the binder has a glass transition temperature no lower than about
-30C. It should be noted that binders having glass transition temperatures
5 below ambient temperatures but no lower than about -30C can yield
coatings which are somewhat tacky at ambient temperatures. Although
such binders still can be used, some applications may require the use of a
release coating or a release paper in order to prevent the coating from
sticking or adhering to the reverse side of the substrate, particularly when
10 the substrate is to be manufactured, stored, and/or transported in roll form.However, the use of a release coating or a release paper can be obviated
by using binders having glass transition temperatures no lower than about
15C, preferably no lower than about ~5C.
The binder in general will constitute from about 80 to about 99
15 percent by dry wei ht, based on the dry weight of the coating, of the
coating. As used herein, however, the term "binder" is meant to be
sufficiently broad to include minor amounts of other materials, such as
dyes, colorants, pigments, plasticizers, flow agents, antistatic agents,
extenders, water repellents, surfactants, viscosity control agents, dispersing
20 aids, and the like. Preferably, the amount of binder present will be in the
range of from about 85 to about 95 percent by dry weight, based on the
dry weight of the coating. The most preferred amount of binder is from
about 88 to about 92 percent by dry weight.
The co~ting also contains from about 1 to about 20 percent by dry
25 weight, based on the dry weight of the coating, of thermally expanded
microbeads. The amount of such microbeads preferably is in the range
- 12 -
2070138
of from about 5 to about 15 percent by dry weight, and most preferably is
in the range of from about 8 to about 12 percent by dry weight.
In general, the thermally expanded microbeads can be any of the
commercially available microbeads, such as those sold under the Expancel~
5 trademark by Nobel Industries Sweden, Sundsvall, Sweden, and those sold
under the Foamcoat0 trademark by Pierce & Stevens Corporation, Buffalo,
New York. While any of the various types of thermally expandable
microbeads can be employed, the more heat-resistant microbeads are
preferred.
The level of coating on a given substrate typically can range from
about 3.7 to about 11.5 g/m2. The preferred range is from about 5.6 to
about 9.4 g/mt. It is neither necessary nor required, though, that the
coating cover all of the bottom surface of the dispensing container.
As already stated, the coating must have a dry static coefficient of
friction, when tested in accordance with ASTM Method 1894 against an
aluminum plate having an anodized surface with a roughness of less than
about 32 microinches (less than about 0.8 llm), of at least about 0.6, and
a dry dynamic coefficient of friction, when similarly tested, of at least
about 0.8.
Coefficients of friction were determined in accordance with ASTM
Method 1894 with a Model 1122 Instron Testing Machine (Instron
Corporation, Canton, Massachusetts). Each sample tested was a 2.5-inch
(6.~cm) square. Dry samples of coated substrates were conditioned for 24
hours at 50 percent relative humidity and 22C. Wet samples were soaked
in 2 g of distilled water for 48 hours. Before testing, the water on the
bottom surface, i.e., the surface not having the smooth nonabrasive antislip
coating of the present invention, was removed by gentle blotting. The
2070138
surface used to determine the coefficients of friction was an aluminum plate
supplied by Instron having a clear anodized surface with a roughness of
less than 32 microinches (less than about 0.8 ~m).
The present invention is further illustrated by the examples which
5 follow. Such examples, however, are not to be construed as in any way
limiting either the spirit or scope of the present invention. In the examples,
all parts are parts on a dry weight basis, unless stated otherwise.
Examples 1-24
Preparation of Coated Papers
Because of the convenience in handling, coating, and testing papers,
as already noted, all of the examples employed paper substrates. Three
di~ferent papers were employed and are described below.
15 Paper A
Paper A was a standard latex-impregnated paper. The basis weight
of the paper before impregnation was 52.6 g/m2. The latex saturant
consisted of 100 parts of Butofan~ 4262, a styrene-but~diene rubber (BASF
Corporation, Sarnia, Ontario, Canada), 30 parts of clay, 2 parts of a
20 colloidal stabilizer, 1 part of a water repellant, and 14 parts of a colorant(the same colorant was used in all saturant and antislip coating dispersions
used in the e~amples). The saturant level in the paper on a dry weight
basis was 26 parts per 100 parts of wood pulp fiber.
A barrier coating was applied to one surface of the paper (referred
25 to herein ~or convenience as the second surface). The barrier coating was
a dispersion which consisted of, on a dry weight basis, l00 parts of
Styronal~ 4574, also a styrene-butadiene rubber (I~ASF, Sarnia, Ontario,
- 14 -
2070~38
Canada), 57.5 parts of Hycar0 2600x106, an acrylic polymer (B. F.
Goodrich Company, Cleveland, Ohio), and 30 parts of clay. The barrier
coating latex was applied with a Meyer rod to provide a coating weight of
15-17 g/m2.
S Paper B
This paper also was a standard latex-impregnated paper. The basis
weight of the paper before impregnation was 52.6 g/m2. The latex saturant
was the same as that used for Paper A, except that the colorant level was
10. The saturant level in the paper on a dry weight basis was 38 parts per
10 100 parts of wood pulp fiber. A barrier was applied to the second surface
as described for Paper A.
Paper C
The paper was a standard latex-impregnated paper having a basis
weight before impregnation of 52.6 g/m2. The latex saturant consisted of
100 parts of Hycar0 1562, an acrylonitrile-butadiene rubber (B. F.
Goodrich Company, Cleveland, Ohio), 4 parts of a phenolic resin, 30 parts
of clay, 1.5 parts of a water repellant, and 9.28 parts of a colorant. The
saturant level in the paper on a dry weight basis was 38 parts per 100 parts
of wood pulp fiber. The paper had the barrier coating of Paper A on the
20 second surface.
With the exception of Example 1 in which the first surface of the
paper substrate was uncoated, the first surface of the paper substrate was
coated with an antislip or control coating by means of a Meyer rod. The
coating was applied in each case at a level of 8.3-9.4 g/m2, on a dry weight
25 basis, except for Examples 20-22, inclusive. The basis weights of the
coatings emplo~ed in ~xamples 20-22, inclusive, were 5.6, 8.5, and 16.2
g/m2, respectively~ Each antislip coating of the present invention was dried
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for one minute at about 107C and then was heated for 10-15 seconds at
165C to expand the microbeads. Both the drying and expanding steps
were carried out in a forced air oven. Coatings not containing thermally
expandable microbeads were simply dried at 107C. The compositions of
5 the dispersions, on a dry weight basis, which were employed to prepare the
various antislip and control coatings tested are summarized in Tables 2-5,
inclusive. In general, the dispersions contained about 45 percent by weight
solids, based on the total weight of the dispersion, with the remainder being
water.
Table 2
Summary of Dispersion Compositions
for Coatings A-F
Parts by Dry Wei~ht in Coating
Com~onent A B C D E F
Rhoplex~ HA16 lOO --- --- lOO --- ---
Styronal0 NI)846 - lOO --- --- --- ---
Butofan0 4262 --- 50 --- --- --- ---
Rhoplex~9 B-15 --- --- --- --- lOO ---
Michem0 4983 --- --- --- --- --- lOO
Styronal0 4574 --- --- lOO --- --- ---
Diatomaceous earth 47 55.6 --- --- --- ---
Clay 57 --- --- --- --- ---
Water repellant --- 11.35 --- --- --- ---
Expancel0 051WU --- --- 15 15 15 15
Colorant 3 3 3 3 3 3
- 16 -
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Table 3
Summary of Dispersion Compositions
for Antislip Coatings ~L
Parts by Weight in Coatin~
Component G H I J K L
Michem~ 4983 100 100 100 100 100 100
Expancel~ OSlWU 15 15 --- 5 30 60
Rosin soap 2 --- --- --- --- ---
Potassium oleate --- 2 --- --- --- ---
Colorant 3 3 3 3 3 3
Table 4
Summary of Dispersion Compositions
for Antislip Coatings M-R
Parts by Wei~ht in Coatin~
Com~onent M N O P Q R
Rhople~ HA16 --- --- --- 100 --- ---
Styronal~ ND846 --- 50 100 --- --- ---
Rhople~9 B-15 --- --- --- --- 100 ---
Styronal0 4574 100 50 --- --- --- 100
Expancel0 O51WU 15 15 15 --- --- ---
Colorant 3 3 3 --- ---
2n70l38
Table 5
Summary of Dispersion Compositions
for Antislip Coatings ~V
Parts by Wt.
in Coating
Component S T
Styronal0 ND846 50 100
Expancel~ 051WU 15 15
Twenty-four different types of sheets were tested, with each type
constituting an e~ample. Examples 1-9, inclusive, constituted controls.
Example 1 consisted simply of an uncoated sheet. Examples 2 and 3
utilized antislip coatings containing inorganic particles. The remaining
15 controls involved the use of various binders without thermally expandable
microbeads being present. Examples 1~24, inclusive, all had an antislip
coating coming within the scope of the present invention. Table 6
summarizes the combination of paper and coating composition for each
example.
Table 6
Summary of Paper and Coating Compositions
Employed in the Examples
Exam~le Paper Coatin~
C ---
2 A A
- 18 -
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3 B B
4 A
S C T
6 C P
7 C S
8 C R
g C Q
C C~
11 C C
12 C J
13 C H
14 C K
C L
16 C D
17 C E
18 C F
19 C G
C O
21 C O
22 C O
23 C N
24 C M
Wet and dry static and dynamic coeff~cients of friction were
25 determined for the sheets o'otained from the examples. It was obserYed,
however, that the curves for the dry dynamic coefficient of friction tests
with the sheets of Examples 8, 9, 10, 11, 16, 17, and 24 were noncontinu-
- 19-
2~7~138
ous. Thus, the dry dynamic values in such instances essentially were
averages of a series of static coefficient of friction cunes and, as a
consequence, may be less reliable. The results are summarized in Table
7.
s
Table 7
Coef~lcient of Friction (COF~ Results
Statie COF Dynamic COF
E~ample Dry Wet Dry Wet
0.220 1.701 0.299 1.701
2 0.169 0.680 0.17S 0.675
3 0.254 0.655 0.275 0.750
4 0.575 1.694 0.277 1.319
lS S 0.399 0.401 0.320 0.654
6 0.387 0.618 0.296 0.657
7 0.626 1.009 0.388 1.250
8 3.103 2.660 0.910 1.842
9 2.028 1.270 1.600 1.295
1.313 0.727 1.763 0.838
11 1.967 0.651 2.750 0.788
12 1.729 1.538 2.074 1.731
13 1.688 1.408 2.000 1.242
14 1.900 1.115 2.004 1.288
lS 1.575 1.144 1.674 1.350
16 0.717 1.710 1.217 1.926
17 1.569 1.329 1.781 1.349
- 20 -
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18 1.938 0.938 2.269 0.909
19 1.650 1.044 1.994 1.110
~.002 1.015 1.291 1.213
21 0.825 1.053 1.131 1.282
22 0.616 1.168 0.821 1.333
23 1.161 1.424 1.265 1.679
24 1.602 2.059 1.454 1.997
In order to aid in understanding and differentiating the coefficient of
10 friction data presented in Table 7, two different calculations were made,
i.e., COFW - COFD and COFW + COF", in which coefficient of friction is
abbreviated as COF with the subscript "W" or "D" to represent a wet or
dry coefficient of friction, respectively. The results of these calculations
are summarized in Tables 8 and 9.
15
Table 8
Summary of Calculations with
Static Coefficient of Friction Data
Static COF Calculations
~cam~le Wet - DryWet + Dry
1.48 1.92
2 0.51 0.85
3 0.40 0.91
4 1.12 2.27
0.00 0.80
6 0.23 1.00
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7 0.38 1.64
8 -0.44 5.76
9 ~.76 3.30
~.59 2.04
11 -1.32 2.62
12 -0.19 3.27
13 ~.28 3.10
14 -0.78 3.02
~.43 2.72
16 0.99 2.43
17 -0.24 2.90
18 -1.00 2.88
19 ~.61 2.69
0.01 2.02
21 0.23 1.88
22 0.55 1.78
23 0.26 2.58
24 0.46 3.66
Table 9
Summary of Calculations with
Dynan~ic Coefficient of Friction Data
Dynamic COF Calculations
E~am~le yy~ Wet + Dry
1.40 2.00
2 0.50 0.85
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2070138
3 0.48 1.02
4 1.04 1.60
0.33 0.97
6 0.36 0.95
7 0.86 1.64
8 0.93 2.75
9 -0.3~ 2.90
-0.92 2.60
11 -1.96 3.54
12 -0.34 3.80
13 -0.76 3.24
14 -0.72 3.29
-0.32 3.02
16 0.71 3.14
17 ~.43 3.13
18 -1.36 3.18
19 -~.88 3.10
-0.08 2.50
21 0.15 2.41
22 0.51 2.15
23 0.41 2.94
24 0.54 3.45
Based on ~he data in Table 8, several conclusions are possible. First,
25 the difference between the wet and dry static coefficients of friction, i.e., COFW - COFD, preferably is in the range of from about -1.5 to about 1.
Second, the sum of the wet and dry static coefficients of friction, i.e.,
2070138
COFW + COFD, preferably is in the range of from about 1.7 to about 3.8.
Second, if the difference between the wet and dry static coefficients of
friction, i.e., COFW - COFD, is less than -0.4 and greater than -1.0, then
the sum of the wet and dry static coefficients of friction, i.e., COFW +
5 COFD, preferably is equal to or less than about 3Ø Third, if the
difference between the wet and dry static coefficients of friction, i.e.,
COFW - COFD, is greater than O and less than 1.0, then the sum of the wet
and dry static coefficients of friction, i.e., COPw + COFD, preferably is
greater than about 1.7
Example 25
Application of Coating to Dispensing Container
The paper of Example 11 was applied to bottom surface of a
15 dispenser-size, Pop-Up0 Space-Saver0 Signal0 Box of Kleenex~9 Brand
facial tissues. The bottom of the container measured 4.75 by 9.5 inches
(12.1 by 24.1 cm~. The paper of Example 11 was cut into two strips, each
of which was 1.5 inches (3.8 cm) wide and 5.5 inches (14 cm~ long. The
strips were affixed with rubber cement along the front and rear edges of the
20 bottom surface of the Kleenex0 Box. Each strip was centered on each
edge, with the front edge of the front strip being contiguous with the front
edge of the boKom surface. Similarly, the rear edge of the rear strip was
contiguous with the rear edge of the bottom surface.
The Kleenex3 Box exhibited a significantly reduced tendency to slip
25 during use when placed on a polished wood surface.
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2~7~138
Having thus described the invention, numerous changes and
modifications thereof will be readily apparent to those having ordinary skill
in the art without departing from the spirit or scope of the invention.
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