Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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= SKID RESISTANT SURFACES
= [0001]
Field of the Invention
[0002] The present invention relates to skid-resistant surfaces
especially when wet,
and in particular to skid-resistant trafficable surfaces such as roofs and
floors as well as
skid resistant packaging for lumber and the like.
Background of the Invention
[0003] Roofing underlayments are typically installed over the roof deck and
under
the primary roof covering or overlayment, which can be asphalt shingles, metal
shingles,
or metal roofing, tiles such as Spanish or slate tile, wood shakes, concrete,
slate, etc. The
underlayment provides a secondary moisture barrier to protect the roof deck
and building
interior from moisture that may penetrate through the primary roof covering.
Commercially effective underlayments must maintain their strength and
integrity even
after exposure to the elements. Underlayments are used both in new
conptruction and in
re-roofing projects.
[0004] It is known in the waterproofing art to combine a pre-
formed waterproofing
membrane, such as a rubberized bitumen/oil layer, with a carrier support sheet
or film,
and to utilize this as an underlayment. The carrier support film may comprise
a variety of
materials, such as rubber, plastic, and/or metal, or combinations of the same.
The use of
metals is desirable, for example, to improve dimensional stability of the
support film,
which is subjected to oil migration from the oil-plasticized bitumen layer. It
has also been
desirable to employ cross-laminated plastic films, such as high density
polyethylene, for
improved stability of the carrier support sheet.
[0005] Such pre-formed waterproofing membrane laminates are
considered "sheet-
like" because they are sufficiently flexible that they can be rolled up and
transported after
manufacture to the job site where they are unrolled and installed on the
building surface.
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This kind of membrane laminate, useful as an underlayment on sloped roofs, is
commercially available from Grace Construction Products (W.R. Grace & Co.-
Conn)
under the name "ICE & WATER SHIELD"(a registered trademark of.W.R.Grace & Co.-
Conn.) The underlayment is applied to the roof deck before installation of the
[0006] Another commercially available example of an underlayment is
"TRI-FLEX
30", (a product also available from Grace Construction Products) which is spun-
bonded
polypropylene coated with a thin layer comprising UN. stabilized polypropylene
on both
10007] In addition to its water shedding capabilities, an important
characteristic of a
roofing underlayment is its skid or slip resistance. Since roofing applicators
must walk
on the underlayment during roofing installation, the exposed surface should
have a
sufficiently high coefficient of friction, even when wet, so as to minimize or
prevent an
20 [0008] It is also desirable that the roofing underlayment be
rollable for ease of
transportation and handling, and be readily unrollable, ideally by a single
person, for
application. However, maintaining unrollability while providing sufficient
skid resistance
can be problematic, particularly where the skid resistance is due to the
tackiness or
stickiness of the walking surface. That is, the same tackiness that is
advantageously used
[0009] It is also desirable that the underlayment be light in weight,
i.e. low weight
per unit area. Lightweight provides for easier transportation to the roofdeck
and easier
installation. Some underlayments comprise a heavy layer of a large particulate
that
[0010] It therefore would be desirable to provide a lightweight roofing
underlayment
having excellent skid resistance while maintaining unrollability.
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Summary of the Invention
[0011] One embodiment of the invention is the provision of a
skid-resistant surface
comprising a substrate coated with a skid resistant layer. In particular, the
present
invention provides a pedestrian trafficable skid-resistant flexible article,
the article
adapted to be stored in a roll and unrolled prior to application to a surface.
The article
=
comprises a flexible substrate suitable for application to a roof, floor or
package (e.g., a
=
pallet of goods), the substrate having a first major surface (e.g., a lower
surface) adapted
to contact said roof, floor or package and an opposite second major surface
(e.g., an upper
surface) adapted to be exposed to pedestrian (or foot) traffic. The second
major surface
has a non-skid coating comprising a pressure sensitive adhesive or a filled
textured
binder. Preferably, the flexible article is in the form of a roofing
underlayment, wherein
upon application of said underlayment to a roof, the non-skid coating provides
a skid
resistant surface for foot traffic thereon. Another application is flexible
packaging, such
as bags, coated with the non-skid coating, which may be stacked without
sliding over one
another.
[0012] In another embodiment of the invention, the skid-
resistant flexible article is in
the form of a lightweight roofing underlayment having excellent skid or slip-
resistance to
=
foot traffic under dry, wet and/or dusty conditions on a sloped surface, and
is both readily
rollable and unrollable as a coherent unit. The underlayment is preferably a
multi-layered
sheet material that includes a support layer comprised of a film or fabric or
both, and a
skid or slip resistant layer on one or both faces of the support layer. The
skid or slip
resistant layer is preferably a pressure sensitive adhesive or a highly filled
textured
binder. The resulting sheet-like underlayment is sufficiently flexible to
allow it to be
formed into rolls and readily installed by unrolling over a support structure
such as a roof
deck. It also provides a sloped walking surface having a high coefficient of
friction and
excellent skid resistance even when wet and/or dusty, and even at high roof
pitches such
as those between about 4:12 and 12:12.
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[0012a] In a specific product aspect, the invention relates to a
pedestrian trafficable
skid-resistant flexible article, said article adapted to be stored in a roll
and unrolled prior to
application to a surface, said article comprising a flexible substrate
suitable for application to
a roof, floor or package, said flexible substrate comprising at least one
support layer
comprising a woven fabric, a non-woven fabric, a polyolefin film, spun bonded
polypropylene
or woven polypropylene and having a first major surface adapted to contact
said roof, floor or
package and an opposite second major surface adapted to be exposed to
pedestrian traffic,
wherein said second major surface has a non-skid coating comprising a filled
textured binder,
wherein the filled textured binder is a pressure sensitive adhesive and
includes inorganic filler
particles in an amount of at least 25 percent by volume of the filled textured
binder, and
wherein at least 98% of the filler particles within a selected 100 cm2 area of
the non-skid
coating are completely coated with the binder.
[0013] In its method aspects, the present invention relates to a
method of forming a
skid-resistant flexible article useful for example as a roofing underlayment
by coating a thin
layer of a pressure sensitive adhesive or a filled textured binder onto a
flexible substrate that
may include a support layer such as a film or fabric, and to a method of
waterproofing a roof
or floor by unrolling the underlayment and applying it to the roof or floor
such as by
mechanical fastening or with an adhesive.
[0014] The present invention also includes a method of making a
pedestrian trafficable
skid-resistant flexible article comprising providing a flexible substrate
suitable for application
to a roof, floor or package, said substrate having a first major surface
adapted to contact said
roof, floor or package and an opposite second major surface adapted to be
exposed to
pedestrian traffic; coating said second major surface with a non-skid coating
comprising a
binder, filler particles and a solvent for the binder; and evaporating the
solvent from said non-
skid coating, whereby the filler particles are substantially coated by the
binder.
[0014a] In a specific method aspect, the invention relates to a method
of making a
pedestrian trafficable skid-resistant flexible article, comprising: providing
a flexible substrate
suitable for application to a roof, floor or package, said substrate having a
first major surface
adapted to contact said roof, floor or package and an opposite second major
surface adapted to
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be exposed to pedestrian traffic; coating said second major surface with a non-
skid coating
comprising a pressure sensitive adhesive, inorganic filler particles and a
solvent for the
pressure sensitive adhesive; and evaporating the solvent from said non-skid
coating, whereby
at least 98% of the filler particles within a selected 100 cm2 area of the non-
skid coating are
completely coated by the pressure sensitive adhesive.
[0015] Another embodiment of the invention is an organic or inorganic
roofing felt
coated with a pressure sensitive adhesive or a highly filled textured binder.
[0016] Another embodiment of the invention is an exposed roofing
membrane coated
with a pressure sensitive adhesive or a highly filled textured binder.
[0017] Another embodiment of the invention is a roof decking comprising
plywood or
other decking material such as oriented strand board coated with a pressure
sensitive adhesive
or a highly filled textured binder.
[0018] Another embodiment of the invention is non-skid flexible
packaging comprising
a support layer coated with a pressure sensitive adhesive or a highly filled
textured binder.
Brief Description of the Drawings
[0019] Figure 1 is a schematic diagram of a roofing underlayment in
accordance with
one embodiment of the present invention.
[0020] Figure 2 is a schematic diagram of a roofing underlayment in
accordance with
another embodiment of the present invention.
[0021] Figure 3 is a schematic diagram of a roofing underlayment in
accordance with
yet another embodiment of the present invention.
[0022] Figure 4 is a schematic diagram of a roofing underlayment in
accordance with
still another embodiment of the present invention.
[0023] Figure 5 is a schematic diagram of a roofing underlayment in
accordance with
a still further embodiment of the present invention.
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[0024] Figure 6 is a schematic diagram of a roofing underlayment in
accordance
with yet another embodiment of the present invention.
[0025] Figures 7A-7C are photomicrographs of a non-skids surface of the
invention
comprising a filled textured binder, looking down from above at the surface.
[0026] Figure 8 is a schematic of a Meyer rod coater.
[0027] Figure 9 is a schematic of a modified Meyer rod coater.
[0028] Figure 10 is a schematic of a gravure coater.
[0029] Figure 11 is a plot of adhesion value, a measure of blocking,
versus adhesive
coating thickness for an SIS pressure sensitive adhesive on various membranes.
[0030] Figure 12 is a plot of adhesion value, a measure of blocking, versus
adhesive
coating thickness for an acrylic pressure sensitive adhesive on various
membranes.
[0031] Figure 13 is a plot of adhesion value, a measure of blocking,
versus adhesive
coating thickness for an SEBS pressure sensitive adhesive on various
membranes.
[0032] Figure 14 is a plot of adhesion value, a measure of blocking,
versus
membrane type for a filled acrylic pressure sensitive adhesive.
[0033] Figure 15 is a plot of adhesion value, a measure of blocking,
versus coating
volume for a filled SEBS pressure sensitive adhesive on various membranes.
[0034] Figure 16 is a plot of adhesion value, a measure of blocking,
versus coating
volume for a filled SEBS pressure sensitive adhesive at various loadings of
filler by
volume.
Detailed Description of the Preferred Embodiments
[0035] One embodiment of the invention is a skid-resistant flexible
article
comprising a flexible substrate coated with a non-skid coating (or skid
resistant layer) that
is skid resistant particularly when wet. The non-skid coating preferably
comprises a
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and silicones, etc. Articles suitable for roofing surfaces further may be
rollable exposed
roofing membranes including rubber sheets, vinyl sheets, and TPO sheets.
Flooring
surfaces include wood-based materials, Portland cement-based materials,
ceramic
materials, naturally occurring stone materials, and synthetic polymeric
materials as well
as composite materials containing combinations of the foregoing.
[0036] Turning first to Figure 1, there is shown one embodiment of the
article of the
present invention in the form of underlayment 10. The underlayment 10 has an
uppermost layer 13 of the non-skid coating (or skid-resistant layer) of the
invention
supported by a flexible substrate or support layer which can be one or more
layers of a
film or fabric, or both. In the embodiment shown in Figure 1, the support
layer is
comprised of a lowermost layer 11 of fabric and an intermediate layer 12 of
film.
Suitable films 12 are those comprised of a synthetic organic polymer such as a
polyolefin
or a blend of polyolefins, and films mentioned as suitable for this layer
hereinafter. The
preferred film is polypropylene or polyethylene or films made from mixtures of
such.
The present invention also contemplates the use of more than one film layer,
such as
layers laminated and/or co-extruded or cross-laminated together. Those skilled
in the art
will appreciate that the underlayments can be produced by any method known in
the art
such as extrusion, lamination and calendaring. The film layer 12 has a
thickness in the
range from 0.5 mils to 10 mils (0.013 mm to 0.25 mm). Preferably, the
thickness is in the
range from 1 mil to 3 mils (0.025 mm to 0.076 mm).
[0037] Suitable fabrics for use in the support layer 11 include both
natural and
synthetic woven and non-woven fabrics, and preferably is synthetic such as a
polyolefin,
such as polypropylene or polyethylene, a polyester, etc., or glass. Preferably
the woven
fabric has less than or equal to 25 percent open space. Woven and non-woven
fabrics
exhibit a weight ranging from 0.5 oz/yd2 (16.9 g/m2) to 10 oz/yd2 (339 g/m2).
Preferably,
woven and non-woven fabrics exhibit a weight in the range from 1 oz/yd2 (33.9
g/m2) to
3 oz/yd2 (102 g/m2).
[0038] In the particular embodiment of Figure 1, the flexible substrate
includes a
support layer comprised of (i) a non-woven or woven fabric layer 11, and (ii)
a synthetic
organic polymer film 12 attached to one surface of the fabric 11. On the
surface of the
synthetic organic polymer film 12 is a non-skid coating (or skid-resistance
layer) 13,
which is a pressure sensitive adhesive or a highly filled textured binder. It
is this skid-
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resistance layer 13 that provides the walking surface for the roof applicator,
and is
ultimately covered by the primary roof covering or overlayment such as
shingles or tiles.
[0039] In the case where fabric layer 11 is a non-woven fabric, it may
be comprised
of one or more synthetic organic polymers such as polyolefins, for example
polypropylene or polyethylene, or may be comprised of polyester. Polypropylene
is
preferred. Where fabric layer 11 is a woven fabric, it may be comprised of one
or more
one or more synthetic polymers such as polyolefins, for example polypropylene,
or
polyethylene, or may be comprised of polyester. The fabric may also comprise a
woven
or non-woven glass fiber mat. Fabrics comprised of polypropylene are preferred
for use
in the embodiment shown in Figure 1.
[0040] The synthetic polymer film 12 as aforementioned comprises one or
more
polymers such as polyolefins, for example polypropylene, polyethylene, a
polymer
comprising ethylene and propylene, a polymer comprising ethylene and methyl
acrylate, a
polymer comprising ethylene and ethyl acrylate, a polymer comprising ethylene
and butyl
acrylate, a polymer comprising ethylene and an alpha olefin, a polymer
comprising
ethylene and vinyl acetate or polyester, and includes mixtures of the
foregoing.
Polyethylene, polypropylene, and mixtures of the two are preferred. The
synthetic
polymer film 12 may also be a coextruded film layer (not shown as such in
Figure 1).
Each layer may comprise one or more of the polymers listed above.
[0041] The laminate comprising the non-woven or woven fabric 11 attached to
a
synthetic organic polymer film 12 may be manufactured by extrusion coating the
layer 12
as a polymer melt onto the fabric.
[0042] Materials suitable for use as the pressure sensitive adhesive
layer 13 comprise
rubbers such as those selected from the group consisting of SIS (styrene-
isoprene-styrene
block copolymers), SBS (styrene-butadiene-styrene block copolymers), SEBS
(styrene-
ethylene-butylene-styrene block copolymers), SBR (styrene-butadiene rubber),
natural
rubber, silicone rubber, butyl rubber, polyisoprene, polyisobutylene,
chloroprene,
ethylene-propylene rubber, ethylene alpha olefin, polybutadiene, nitrile
rubbers, and
acrylic rubber. A rubber modified bitumen pressure sensitive adhesive may also
be used.
All of the rubbers listed above, except silicone, may be blended with bitumen
to produce
a pressure sensitive adhesive. Preferably the pressure sensitive adhesive
comprises a
weatherable rubber such as those selected from the group consisting of SEBS,
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polyisobutylene, acrylic, silicone, and butyl. Preferably the pressure
sensitive adhesive
used is free of surfactant, since the presence of surfactant tends to reduce
the skid
resistance when the surface is wet.
[0043] A pressure sensitive adhesive generally comprises a
rubber, a tacldfier, and a
=
plasticizer. The plasticizer and tacicifier modify the properties of the
rubber to make it
pressure sensitive. A plasticizer is generally a low molecular weight
ingredient that is
compatible with the rubber (e.g., a naphthenic or aliphatic oil). It lowers
the plateau
modulus of a mixture of rubber and plasticizer vs. the rubber alone: A
tacldfier is
generally a low molecular weight ingredient (e.g., a C5 or C9 hydrocarbon
resin) that is
= 10 compatible with the rubber and increases the glass transition
temperature of the rubber
blend. It also lowers the plateau modulus of the rubber blend vs. the rubber
alone. These
features are known to those skilled in the art of pressure sensitive adhesive
formulation.
[0044] The pressure sensitive adhesive may comprise rubber
alone. Such is the case
for some acrylic polymers such as butyl acrylate and ethyl-hexyl agylate that
are
inherently pressure sensitive.
[0045] Preferably the pressure sensitive adhesive layer 13 is
used in a thickness of
less than or equal to about 10 gm, more preferably less than or equal to about
5 pm. Use
of such a thin pressure sensitive layer insures good skid resistance,
including wet skid =
resistance, while maintRining the ability to unroll the membrane and insure
that a
pedestrian does not stick to the surface while walking on it. The ability to
unroll and/or to
prevent too much adhesiveness is measured using an accelerated blocking test
as
described in Example 1. Following this test, one can measure the blocking
level as a peel
force in pounds per square inch (pli). It is preferred that coatings of the
present invention
= have a blocking level Of less than 1 pli, preferably about 0.5 pli or
less (e.g., 0.05 to 0.5
ph).
[0046] For embodiments where the non-skid coating 13 is a
pressure sensitive
adhesive, the pressure sensitive adhesive exhibits a minimum peel adhesion
value of 1
pound per linear inch (ph) to the support sheet. Adhesion is measured by
applying a one
inch wide tape comprising a 5 mil (0.13 mm) layer of the pressure sensitive
adhesive
laminated to the face of a 4 mil (0.10 mm) thick cross-laminated, high density
polyethylene sheet such as ValeronT.m, a commercial product of Valeron
Strength Films,
to the substrate. This "tape" may be prepared by coating the pressure
sensitive adhesive
=
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from solution and drying, or coating the molten pressure sensitive adhesive at
elevated
temperature onto the 4 mil Valeron. The face of the pressure sensitive
adhesive side of
the one inch wide tape is applied to the substrate. The construction is rolled
in four times
in one second passes with a 30 pound roller. Adhesion is measured fifteen
minutes later
with a mechanical test device such as an Instron using a peel angle of 90
degrees and a
cross-head speed of 2 in./min.
[0047] In the embodiment where the non-skid coating 13 is a filled
textured binder,
the binder is a material that adheres to both the filler and the support
sheet, as described in
a test below, and is organic solvent soluble. Preferred binders include:
pressure sensitive
adhesives as described above for a skid resistant layer comprising only a
pressure
sensitive adhesive, rubbers, and resins. Another preferred binder comprises an
amorphous polyolefin like those produced by Eastman Chemical under the trade
name
"Eastoflex."
[0048] For binders that comprise a rubber, the rubber is selected from
the group
consisting of SIS (styrene-isoprene-styrene block copolymers), SBS (styrene-
butadiene-
styrene block copolymers), SEBS (styrene-ethylene-butylene-styrene block
copolymers),
SBR (styrene-butadiene rubber), natural rubber, silicone rubber, butyl rubber,
polyisoprene, polyisobutylene, chloroprene, ethylene-propylene rubber,
ethylene alpha
olefin, polybutadiene, nitrile rubbers, thermoplastic polyurethanes (TPUs),
thermoplastic
polyolefins (TP0s), and acrylic rubber. Preferably the rubber is weatherable
such as
those selected from the group consisting of SEBS, polyisobutylene, acrylic,
silicone, and
butyl. Preferably the rubber used is free of surfactant, since the presence of
surfactant
tends to reduce the skid resistance when the surface is wet.
[0049] For binders that comprise a resin the resin may be selected from
a group of
materials including hydrocarbon resins, C-5 hydrocarbon resins, C-9
hydrocarbon resins,
(C-5)2 hydrocarbon resins, rosin acids, rosin esters, terpene resins,
coumarone indene
resins, phenol formaldehyde resins, urea formaldehyde resins, melamine resins,
polyester
resins, acrylic resins, alkyd resins, bitumen, aldehyde and ketone resins,
amides and
polyamides, amines and polyamines, maleic resins, melamine resins, oxazole
resins,
phenolic resins, phenoxy resins, phthalic anhydrides, styrene resins, urea
resins, vinyl
resins. Preferably, the resin has a Tg or ring and ball softening point that
is greater than
or exceeds 75 F. More preferably the resin has a Tg or ring and ball
softening point that
is greater than or exceeds 140 F.
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[0050] Adhesion of the filled textured binder to the support sheet (or
substrate) is
measured in a peel adhesion test using a pre-formed pressure sensitive tape. A
2 in. wide
preformed tape, Preprufe Tape (W.R. Grace Co.-Conn.), is applied to the non-
skid
coated face of the underlayment. The sample is rolled 4 times, at 1 second per
pass, with
a 30 lb roller. Adhesion is measured in a T-peel adhesion test 15 min after
rolling at a
cross head speed of 2 in. per minute with an Instron mechanical tester. The
peel adhesion
value must be greater than 1 pound per linear inch (ph). Preferably, the
adhesion value is
greater than 2 pounds per linear inch.
[0051] In the embodiment where the skid resistant layer 13 is a filled
textured binder
the filler particles, including those on the exterior surface of the coating,
are preferably
substantially coated with binder and the coating is textured. "Substantially
coated" means
that at least about 95 percent of the filler particle's surface is coated.
More preferably,
substantially coated means that at least 98%, and most preferably at least
99%, of the
filler particles within a selected area (e.g., 100 cm2) are completely coated
or
encapsulated by the binder coating material. By "textured" is meant that the
filler
particles protrude from the surface and, thus, the surface coating is uneven
(or textured)
rather than being smooth or planar. This texturing is clearly visible, as
shown in figures
7A to 7C, where the individual coated filler particles are shown in SEM
photomicrographs. The filler particles are substantially coated with binder as
a result of
the preferred manufacturing process. This process involves producing a coating
comprising the binder, the filler particles, and a solvent that dissolves the
binder, applying
the coating to a substrate, and removing the solvent by evaporation thereby
depositing a
layer of coating containing the encapsulated filler particles onto the
substrate.
[0052] The filler particles may be inorganic or organic and are
included in an amount
of at least about 25 percent by volume of the filled textured binder (i.e.,
the dried coating
after solvent evaporation), preferably in an amount of at least about 33
percent by
volume, more preferably in an amount of at least about 45 percent by volume,
most
preferably at least 50% by volume. Use of a high filler volume, including
amounts up to
about 75%, insures that the filled binder is textured. A range of about 30% to
60% filler
by volume is ideal. If the filler volume is too low the layer is relatively
smooth. The
filler has a maximum average particle size of up to about 100 [tm. Preferably
the filler
has a maximum average particle size of less than about 50 m. More preferably
the filler
has a maximum average particle size of up to about 25 p.m. Filler particles in
the range of
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about 0.1m to about 20 [tin, preferably about 0.5 pm to about 15 p.m, are
ideal. Larger
particle sizes hinder the coating application process, and add excessive
weight to the
underlayment. The term "particles" as used herein is intended to encompass
particles
having regular (e.g., spherical) or irregular shapes, as well as shards.
Suitable inorganic
fillers include calcium carbonate, silica, clay, talc, vermiculite, mica,
titanium dioxide, fly
ash, alumina trihydrate, and slag. The fillers may be surface treated with a
bonding agent
to enhance bonding to the binder and ease of dispersion in the solvent.
Optional bonding
agents include silanes, titinates, and long chain acids like stearic acid. In
addition a
dispersant may be used to aid in the dispersion of filler particles in the
solvent. The
coating volume of the filled textured binder layer is up to about 10 cubic
centimeters per
square foot (cm3/ft2) (107.6 cm3/m2), preferably less than about 5cm3/ft2
(53.8 cm3/m2),
more preferably less than about 2cm3/ft2 (21.5 cm3/m2), and most preferably
less than
about lcm3/ft2 (10.8 cm3/m2). An ideal volume is 0.2 ¨ 2 cm3/ft2 (2.15 ¨ 21.5
cm3/m2).
[0053] Inorganic particulates that react with water may also be used.
These include
Portland cement, calcium oxide, high-alumina cement, blast furnace slag,
pozzolanas, and
pozzolanic cement. These fillers may hydrate after the underlayment is
installed on the
roof deck. The net effect is an increase in the average size of the
particulate after the
membrane is installed.
[0054] Some underlayments of the present invention are textured at two
levels.
These include embodiments where the support sheet comprises a woven or a non-
woven
fabric in direct contact with non-skid layer 13 or separated from non-skid
layer 13 by a
thin polymer film 12. One level of texturing is provided by the filler.
Another level of
texturing is provided by the fabric. While not being bound by theory, it is
believed that
both levels of texturing contribute to the perfoi mance of the
underlayments. The dual
texturing enhances resistance to "blocking" (the tendency of the front face of
the
underlayment to stick to its rear face when unrolled) by minimizing contact
between
opposite faces of the underlayment within a roll of underlayment. The dual
texturing also
enhances skid resistance by enhancing mechanical interlock between the surface
of the
underlayment and the sole of a shoe in contact with the surface of the
underlayment. The
dual texturing also enhances skid resistance by providing channels for
lubricant migration
when a shoe sole comes into contact with an underlayment that is coated with
lubricant(s). Lubricants include water and dirt. To avoid skidding the
lubricant must be
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channeled away from the contact area between a shoe sole and the surface of
the
underlayment.
(00551 The pressure sensitive adhesive layer and the filled textured
binder layer are
preferably coated as a solution in an organic solvent. For example, a coating
solution
comprising binder, filler particles and an organic solvent is coated onto a
flexible
substrate comprising the support layer, and the solvent is removed by
evaporation to leave
the non-skid coating. The coating solution may be applied to the substrate by
brush,
roller, or spray application, and may be a continuous process such as spray,
roll coating,
gravure coating, knife coating, and wire wound rod coating (i.e., Meyer rod
coating). The
resulting coated substrate can then be wound into a roll. Suitable organic
solvents include
those that will completely dissolve the pressure sensitive adhesive or the
binder and also
exhibit a high vapor pressure so that evaporation can be affected quickly in
the coating
process. For example, hydrocarbon solvents such as heptane may be used. Other
useful
solvents include methyl ethyl ketone and toluene. It is also contemplated that
the coating
solution may be applied as an aqueous emulsion.
[0056] Another embodiment of the invention includes a skid resistant
flexible article
in the form of a roofing underlayment comprising a woven fabric, a non-woven
fabric, a
film, or a combination of these and a non-skid coating comprising a pressure
sensitive
adhesive or a highly filled textured binder. A preferred underlayment
comprises a spun
bonded polypropylene substrate, both sides of which have been extrusion coated
with a
polyolefin, and an underlayment comprising a woven fabric that is laminated to
a
polyolefin film.
[0057] Figure 2 illustrates a second embodiment of the present
invention. The
underlayment 21 comprises a non-woven or woven fabric layer 11, a synthetic
organic
polymer film layer 12 adhered to both faces of the fabric 11, and a pressure
sensitive
adhesive layer or filled textured binder layer 13 on the surface of the
polymer film 12.
The polymer film 12 may be a coextruded layer (not shown) polymer film.
[0058] Yet another embodiment is shown in Figure 3, where the
underlayment 22
comprises a non-woven or woven fabric 11, a synthetic organic polymer film 12
adhered
to both faces of the fabric 11, a pressure sensitive adhesive layer or filled
textured binder
layer 13 on the surface of one of the polymer film layers 12, and a further
non-skid layer
14 on the surface of the other polymer film layer 12. The non-skid layer 14
can minimize
12
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= 66925-662
or prevent relative movement between the underlayment and the roofing deck
during and
after installation. Suitable non-skid layers 14 include one or more
polyolefins such as
polyethylene, polypropylene, a polymer comprising ethylene and propylene, a
polymer
comprising ethylene and methyl acrylate, a polymer comprising ethylene and
ethyl
acrylate, a polymer comprising ethylene and butyl acrylate, a polymer
comprising
ethylene and vinyl acetate, a polymer comprising ethylene and an alpha olefin,
and a
polymer comprising ethylene and octene. The non-skid layer 14 preferably has a
thickness of less than about 1 mil (0.0254 mm), and exhibits a Shore D
hardness, ASTM
1D2240, of less than about 45.
=
[00591 The multi-layer synthetic organic polymer film 12 and 14 in Figure 3
may be
co-extrusion coated onto the fabric 11 to produce a structure comprising
layers 11, 12 and
14 of underlayment 22. Synthetic polymer layer 12 is extrusion coated to the
other face
of fabric 11. This may also be a coextruded layer (not shown) The non-skid
layer 13 then
may be applied to such structures to produce the underlayment of Figure 3 by
coating, as
a mixture with an organic solvent that dissolves the organic portion of the
coating, onto a
web comprising a support in a continuous web coating operation. The solvent is
removed
by evaporation and the resulting underlayment is wound into rolls. Various
types of
= coaters may be used to apply the organic solvent based coating, including
wire wound rod
(also called Meyer rod), roll coater, gravure coater, air knife, and a knife
over roll coater.
[00601 Figure 8 is a schematic of "Meyer" rod coating using a wire wound
rod, the
preferred coating method used herein. In Meyer rod coating, a coating roll 31
is situated
in a bath 30 filled with coating. A layer of coating is deposited on the
coating roll 31 as
=
=
the roll is rotated. Coating from the roll is transferred to the web 34 fed by
rollers 33 comprising
the support sheet. The wire-wound metering rod 32 sometimes known as a "Meyer
Bar",
allows the desired quantity of the coating to remain on the substrate 34. The
excess
coating is deposited back into the pan 30. The quantity metered on to the
substrate is
determined by the diameter of the wire used on the rod. For coatings
comprising a highly
filled textured binder the machine design may be modified to accommodate
potential
problems with filler settling during the coating process. Filler particles may
tend to settle
in the bath 30 of Fig. 8. This is particularly important when a low viscosity
coating is
applied. One option is to recirculate the coating in the pan. This may be
facilitated with a
tapered pan 35 design and recirculation system 36 and 37 as shown in Figure 9.
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[0061] Figure 10 shows a schematic of gravure coating. The gravure
coater depends
on an engraved roller 38 running in a coating bath that fills the imprinted
dots or lines of
the roller with the coating material. The excess coating on the roller is
removed by the
doctor blade and the coating is then deposited onto the substrate as it passes
through the
engraved roller and a pressure roller. As immediately applied to the web, the
coating is
textured. If the coating viscosity is low and or solvent evaporation is slow,
the textured
pattern levels to produce a smooth coating except for filler particles that
are thicker than
the binder layer. If the coating viscosity is high and or solvent evaporation
is fast, then a
textured pattern results after solvent evaporation. This may be affected for a
non-skid
layer comprising a pressure sensitive adhesive (no filler) or a filled
textured binder. For a
non-skid layer comprising a filled textured binder the net effect is to have 2
levels of
texturing. The smaller-scale texturing is contributed by the filler particles.
The larger-
scale texturing is related to the gravure roll pattern.
[0062] Figure 4 illustrates a further embodiment 23 that comprises a
woven fabric
layer 15 with less than or equal to 25 percent open space, a pressure
sensitive adhesive
layer or filled textured binder layer 13, a lamination layer 20, a polymer
film 16 and a
second non-skid layer 14. Layer 15 comprises a material selected from a list
including
polyethylene, polypropylene, polyester, or glass. The weight of layer 15 is
0.5 oz/yd2 to
10 oz/yd2 (16.9 g/m2 to 339 g/m2). Preferably, the weight of layer 15 is 1
oz/yd2 to
3 oz/yd2 (33.9 g/m2 to 102 g/m2). Options for materials for layer 14 are
described above.
Layer 16 is a polymer film comprising one or more materials selected from the
group
including polypropylene, polyethylene, a polyolefin, or polyester. The
thickness of layer
16 is 0.5 mils to 10 mils (0.013 mm to 0.254 mm). Preferably the thickness of
layer 16 is
1 to 3 mils (0.025 mm to 0.076 mm). Polypropylene is preferred. Layer 20
adheres layer
15 to layer 16. Layer 20 may comprise the same materials as previously
described above
for layer 12. The film layer 20 has a thickness in the range from 0.5 mils to
10 mils
(0.013 mm to 0.254 mm). Preferably, the thickness of layer 20 is in the range
of 1 to 3
mils (0.025 mm to 0.076 mm).
[0063] Layer 20 may also comprise a pressure sensitive adhesive as
described above
for layer 13. Layer 20 may also comprise bitumen. Layer 20 may also comprise
rubber
and bitumen. For the case where layer 20 comprises a pressure sensitive
adhesive,
bitumen, or bitumen and rubber, the thickness is in the range from 1 mil to 50
mils (0.025
mm to 1.27 mm). For the case where layer 20 comprises a pressure sensitive
adhesive,
14
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bitumen, or bitumen and rubber the underlayment 23 exhibits nail sealing
characteristics,
i.e. the material of layer 20 tends to seal around nails that are made to
penetrate the
underlayment 23.
[0064] The underlayment 23 of Fig 4 may be made in several ways. A
preferred
process is described as follows. A coextruded film comprising layers 14 and 16
is made
in a coextrusion process. Next the coextruded film 14/16 is laminated to woven
fabric 15
via extrusion lamination with lamination layer 20. A solution comprising a
pressure
sensitive adhesive or filled textured binder is coated on to the other face of
woven fabric
15, and the solvent is removed via evaporation leaving layer 13.
[0065] The embodiment 24 of Figure 5 shows a polyethylene or polypropylene
film
17, and a layer of pressure sensitive adhesive 13 on one face thereof. Cross-
laminated
films are preferred, such as cross-laminated films commercially available from
Van Leer
under the trademark VALERON. Other suitable cross-laminated films are those
manufactured by Interplas/Formosa.
[0066] Another embodiment of the invention (not shown) is an organic or
inorganic
roofing felt coated with a pressure sensitive adhesive or a filled textured
binder. An
organic roofing felt comprises paper saturated with asphalt. An inorganic
roofing felt
comprises a non-woven glass fabric saturated with asphalt.
[0067] Figure 6 illustrates an embodiment 25 of a self-adhering
underlayment
comprising a support layer 19, a pressure sensitive adhesive layer or filled
textured binder
layer 13 on one major surface thereof, and a second pressure sensitive
adhesive 18 on the
opposite major surface thereof. The pressure sensitive layer 18 may include
rubber
modified bitumen, and non-bituminous adhesives comprising rubbers such as SIS,
SBS,
SEBS, SBR, natural rubber, silicone, butyl rubber, isoprene, butadiene and
acrylic rubber.
Preferably the layer 18 is used in a thickness of greater than or equal to 5
mils (0.13 mm),
more preferably greater than or equal to 20 mils (0.51 mm).
[0068] The support layer 19 comprises a film, a woven fabric, a non-
woven fabric,
or a combination of these. Preferably, the films comprise a polyolefin,
polyethylene,
polypropylene, a polyester, or a combination of these materials.
[0069] The non-skid underlayments of the present invention exhibit a unique
combination of valuable features in comparison to other underlayments
including:
excellent skid resistance, yet are still trafficable (the shoe soles of a
pedestrian walking on
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the surface of an underlayment of the present invention do not become stuck to
the
underlayment), particularly when wet, lightweight, rollable, and unrollable.
For
embodiments comprising a filled textured binder, where the binder is a
pressure sensitive
adhesive or a rubber, a unique combination of mechanisms act to impart a high
coefficient of friction, particularly when wet. Futheiniore, for embodiments
comprising a
filled textured binder the filler is better adhered to the support sheet in
comparison to the
case for other underlayments where the surface comprises an exposed filler or
aggregate.
[0070] Skid resistance is demonstrated in example 2 below.
Underlayments of the
present invention are lightweight in comparison to other underlayments (and
other
roofing products) comprising filler or aggregate on the surface because a
moderate level
of filler is used and the particle size of the filler is small.
[0071] It was also surprising that a surface could be rendered skid
resistant with a
pressure sensitive adhesive without compromising the ability to unroll the
membrane or
walk on the membrane without becoming stuck. For embodiments where the skid
resistant layer comprises only a pressure sensitive adhesive this is achieved
by use of a
very thin layer of pressure sensitive adhesive, typically less than 10 m
thick, preferably
less than about 4m thick, more preferably less than about 3 um thick. If a
thick layer of
pressure sensitive adhesive were used as the non-skid layer the underlayment
would be
impossible or difficult to unroll. For example, for a 30 in. (76 cm) wide
membrane the
minimum force required to unroll the membrane comprising more than about 5
mils (0.13
mm) of pressure sensitive adhesive or binder would be equal to or greater than
30 lbs.
For embodiments comprising a filled textured binder, where the binder is a
pressure
sensitive adhesive or rubber, (rubbers are slightly tacky) excellent skid
resistance,
particularly when wet, is achieved by the use of a thin non-skid layer that is
textured with
a small particle size filler.
[0072] While not being bound by any specific theory, it is believed
that non-skid
properties are provided by adhesion of the non-skid coated underlayment to the
shoe sole
of the walker and, where the coating includes filler particles, an additional
mechanical
interlock of the non-skid coated underlayment to the shoe sole of the walker.
For
embodiments of the invention where the binder is a resin, it is believed that
mechanical
interlock substantially provides for skid resistance because the resins
provide little or no
adhesion.
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[0073] The
preferred manufacturing method comprises providing a coating solution
comprising a mixture of an organic solvent, binder, and filler particles, and
coating the
coating solution onto a flexible substrate (or support layer), then removing
the solvent by
evaporation. This method is preferred because the filler is well bonded to the
support
sheet in comparison to other manufacturing methods by virtue of being
substantially
coated with binder. Other methods may be utilized to coat a filled textured
binder on to a
support sheet. Of course, other underlayments and other roofing products also
may be
utilized in accordance with the present invention.
[0074]
Other applications for the non-skid coating are contemplated. The non-skid
layers of the present invention may be applied to plywood and oriented strand
board. Use
of these coated decking materials enhances skid resistance particularly when
these
materials are used on a sloped roof deck. Another application is non-skid
flexible
packaging materials. For example, plastic sacks may be coated with the non-
skid layers
of the present invention to prevent sliding of stacked arrays of products.
[0075] Coating compositions may be prepared by a variety of methods with
various
types of mixers, e.g., horizontal and vertical batch type mixers. Ideally, a
medium
intensity or high intensity mixer is used, such as, for example, a medium
intensity
horizontal paddle mixer, a high speed Cowels dissolver, a rotor/stator high
speed mixer,
and others. An in-line rotor stator mill or an in-line media mill are
particularly useful for
effectively dispersing filler(s) into a binder coating. For coatings
comprising a pressure
sensitive adhesive, the solvent is charged into a batch type mixer and the
agitator is turned
on. Adhesive ingredients including rubber(s), plasticizer(s) and tackifier are
metered into
the mixer and mixed until dissolved. Alternatively, the pressure sensitive
adhesive may
be hot melt compounded, formed into blocks or chips, cooled, added to solvent
in a batch
type mixer, and mixed until dissolved. For coatings that comprise a pressure
sensitive
adhesive and a filler, a solution of the pressure sensitive adhesive may be
prepared first
followed by filler addition and additional mixing. Alternatively, filler and
adhesive
ingredients may be added simultaneously to solvent in a batch mixer. After all
ingredients are combined, the mixture of solvent, binder, and filler may be
circulated
through an in-line mixer like a rotor stator in-line mixer or a media mill to
affect optimal
mixing. If the binder comprises only rubber, the rubber is added via
procedures similar to
those described above for adhesives.
17
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Example 1
[0076] A blocking test was conducted, which is a severe test designed
to develop an
understanding of blocking on a relative basis. A control membrane, a
polyolefin (PO)
coated non-woven is easily unrolled. The polyolefin coated control membrane
comprises
a 2 oz/yd2 (67.8 g/m2) non-woven polypropylene fabric coated on each side with
1.25
mils (0.032 mm) coextruded layer. On the side in contact with the skid-
resistant layer the
coex layer comprise 1.0 mil (0.0254 mm) layer PP/LDPE blend and a 0.25 mils
(0.006
mm) layer comprising a copolymer of ethylene and methyl acrylate. The thin
layer faces
outward. The coex layer on the other side of the non-woven comprises a 1 mil
layer of a
PP/LDPE blend and a 0.25 mil layer comprising an ethylene/propylene copolymer.
The
thin layer faces outward. If an experimental membrane exhibits an ability to
unroll as
easily or more easily versus the control in the accelerated test, than it is
assumed that the
experimental membrane will unroll easier than the control under normal
circumstances.
[00771 The accelerated tests involve the application of high pressure
and high
temperature. Two sheets of membrane are positioned on top of the other with
the
surfaces to be tested in contact with one another. The sheets are sandwiched
between 2
steel plates. The assembly is loaded in a heated press to 250 psi at 75 C for
16 hrs. The
force required to peel the sheets apart is then measured with a mechanical
test device such
as an Instron. The peel rate is 2 in/min. A T-Peel test geometry is used.
Results are
shown in the five Tables below. In the Tables, "SIS" is a
styrene/butadiene/styrene block
copolymer, "PO" is polyolefin, "PP" is polypropylene, "HDPE" is high density
polyethylene, "SEBS" is styrene/ethylene/butylene/styrene block copolymer, and
"PSA"
indicates a pressure sensitive adhesive.
[0078] In Figures 11-13, peel force, a measure of blocking, is plotted
versus the
pressure sensitive adhesive coating thickness. An SIS, acrylic, and an SEBS
pressure
sensitive adhesive were evaluated by coating on different membranes including
a
polyolefin coated non-woven (described above), a membrane that comprises a 2
oz/yd2
polypropylene woven fabric laminated to a 1 mil (0.0254 mm)
polypropylene/ethylene
vinyl acetate wherein the ethylene vinyl acetate layer faces outward
coextruded film with
1 mil of a polypropylene/polyethylene mixture, and an HDPE film which is 3 mil
(0.076
mm) Valeron.
18
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[0079] With the exception of the acrylic coated HDPE film, all pressure
sensitive
adhesive coated webs exhibited a lower resistance to blocking versus the
control (Figures
11 to 13).
[0080] Blocking was also evaluated for membranes coated with a filled
textured
acrylic pressure sensitive adhesive and the results are shown in Figure 14.
The filled
coating comprises 75 percent, by weight, of a 325 mesh calcium carbonate. The
volume
of the coating on each membrane was about 0.93 cm3/ft2 (10.0 cm3/m2) (weight =
16g/yd2). All membranes coated with the filled pressure sensitive adhesive
exhibit lower
resistance to blocking versus the control.
[0081] Blocking was also evaluated for membranes coated with a filled
textured
SEBS pressure sensitive. The filler is 325 mesh calcium carbonate. The effects
of
coating volume and membrane type were evaluated. Coating volume was varied
between
about lcm3/ft2 to 15cm3/ft2 (10.8 cm3/m2 to 161 cm3/m2). Two membranes were
evaluated. One comprises the polyolefin coated non-woven as described above.
The
other comprises the polypropylene woven as described above. The results are
given in
Figure 15. Note that the level of blocking is proportional to the coating
volume. The
blocking level exhibits a peel force of less than 0.5 ph i (pound per linear
inch) for coating
volumes less than about 10 cm3/ft2 (108 cm3/m2).
[0082] Blocking was also evaluated for membranes coated with a filled
textured
SEBS pressure sensitive adhesive and the results are shown in Figure 16. The
effects of
filler volume percent and the effects of coating volume on blocking were
evaluated. The
filler was a 325 mesh calcium carbonate. Blocking is lowest for underlayments
comprising a low coating volume and a high percent by volume of filler. For
the
underlayment comprising a coating with 27 percent filler by volume and 10.3
cm3/ft2 of
coating blocking is severe.
Example 2
[0083] Skid resistance was measured in a "walk on" test as follows.
Underlayment
specimens to be tested were mechanically attached to a sheet of plywood and
positioned
at a test angle of 40 . The samples were sprayed with water prior to testing.
A tester
("walker") walks over the sample and compares the wet skid resistance of the
sample to a
"control", which was a membrane comprising a 2 side polyolefin-coated
polypropylene
non-woven described above. The "walker" judges the sample membrane to exhibit
better,
19
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similar or worse skid resistance versus the control membrane. The results for
various
underlayments tested are shown in Table 1. Samples 1-13 are embodiments of the
present invention and all exhibit superior wet skid resistance in comparison
to the control
membrane. It is also important to note that water-based binders comprising a
surfactant
impart poor wet skid resistance. See test results for specimens 25 to 27 in
Table 1 where
all of the non-skid layers are acrylic emulsions commercially available from
Rohm and
Haas company. In the "walk on" test, these binders have poor wet adhesion to
the
support sheet which contributes to poor wet skid resistance. It is believed
that the
surfactant also lowers the surface tension of water on the wet surface which
contributes to
poor wet skid resistance.
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Table 1
No. Support Layer Non-Skid Layer Wet Skid
Resistance
1 2 side polyblefin coated non-woven
polypropylene' 5u SIS PSA Better
2 2 side polyolefin coated non-woven polypropylene'
5u SEBS PSA Better
3 2 side polyolefin coated non-woven polypropylene'
5u Acrylic PSA Better
4 Woven polypropylene-polypropylene film laminate2
51.1 SIS PSA Better
Woven polypropylene-polypropylene film laminate2 = 5u SEBS PSA Better
6 Woven polypropylene-polypropylene film laminate2
Su Acrylic PSA Better
1cc/ft2 -325 mesh CaCO3/SIS PSA (53% by
7 2 side polyolefin coated non-woven polypropylene'
volume CaCO3) Better
i 1cc/ft2 -325 mesh CaCO3/SEBS PSA (53 k by
8 2 side polyolefin coated non-woven
polypropylene' volume CaCO3) Better
1
1cc/ft2 - 325 mesh CaCO3/acrylic PSA (53% by
9 2 side polyolefin coated non-woven
polypropylene volume CaCO3) Better
lcc/ft2 -326 mesh CaCO3/SIS PSA (53% by
Woven polypropylene-polypropylene film laminate2 volume CaCO3) Better
1cc/1t2 -325 mesh CaCO3/SEBS PSA (53% by
11 Woven polypropylene-polypropylene film laminate
volume CaCO3) Better
2 1cc/ft2 - 325 mesh CaCO3/acrylic PSA (53% by
12 Woven polypropylene-polypropylene film laminate
-
volume CaCO3) Better
2cc/ft2 - Portland Cement/amorphous polyolefin
2 side polyolefin coated non-woven polypropylene' (Eastoflex P1010-Eastman)
(53% by volume Better
13 Portland Cement)
53 1 cc/ft2 - 325 mesh CaCO3/butyl rubber ( /v
b'
Woven polypropylene-polypropylene film laminate volume CaCO3)= µ
Better
14
2 1 cc/1t2 -325 mesh CaCO3/chloroprene rubber
Woven polypropylene-polypropylene film laminate =
(53% by volume CaCO3) Better
16 2 side polyolefin coated non-woven polypropylene"
none NA (control)
17 Woven polypropylene-polypropylene film laminate
none Same
2 side polyolefin coated non-woven polypropylene' 1 oz/yd2 hot melt spray
applied amorphous Same
18 polyolefin (Eastoflex P1010-Eastman)
Woven polypropylene-polypropylene film laminate2 1 oz/yd2 hot melt spray
applied amorphous Same
19 polyolefin (Eastoflex P1010-Eastman)
EPDM Rubber Sheet none Same
,
2 side polyolefin coated non-woven polypropylene' 2 to 3 oz/yd2 embossed
low molecular weightSame
21 polyethylene/tackifier blend (70/30 by weight)
Woven polyp 2 2 to 3 oz/yd2
embossed low molecular weight
polypropylene-polypropylene film laminate Same
22 polyethylene/tackifier blend (70/30 by weight)
Web comprising HPDE woven fabric and polyolefin grid
polyolefin coated polyolefin grid with nodes Same
23 with nodess
Web comprising
spunbonded/thermobonded spunbonded/thermobonded polypropylene non-
Worse
24 polypropylene non-woven fabric surface"'
woven fabric surface
Woven polypropylene-polypropylene film laminate2 4 cc/ft2 - CaCO3/dry Acronal
S400 (53% byWorse
volume CaCO3)
Woven polypropylene-polypropylene film laminate2 2.8 cc/ft2 - CaCO3/dry
Acronal A3234 (53% by Worse
26 volume CaCO3)
Woven polypropylene-polypropylene film laminate2 4.1 cc/ft2 - CaCO3/dry
Acronal V275 (53% by Worse
27 volume CaCO3)
Acronal S400 acrylic emulsion 2.3
Acronal A3234 acrylic emulsion 1.2
Acronal V275 acrylic emulsion 1.9
1 - 2 oz/yd non-woven polypropylene fabric coated on
each side with 1.25 mils coex layer. On the side in
contact with the skid-resistant layer the coex layer
comprise 1.0 mil layer PP/LOPE blend and a 0.25 mils
layer comprising a copolymer of ethylene and methyl
acrylate. The coax layer on the other side of the non-
woven comprises a 1 mil layer of a PP/LOPE blend and
a .25 mil mayer comprising an ethylene/propylene
copolymer
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Example 3
[0084] Adhesion of the non-skid coating to the support sheet is
measured in a peel
adhesion test using a pre-formed pressure sensitive tape. A 2 in. wide
preformed tape,
"Preprufe Tape", is applied to the non-skid coated face of the underlayment.
The
sample is rolled 4 times, at 1 second per pass, with a 30 lb roller. Adhesion
is measured
in a T-peel adhesion test 15 min after rolling at a cross head speed of 2 in.
per minute
with an Instron mechanical tester. Results for various underlayments
comprising a woven
polypropylene mesh coated with a filled textured binder are shown in Table 2.
Note that
all underlayments, exceptfor that comprising gilsonite, passes the minimum
adhesion
requirement for an underlayment comprising a filled textured binder. Also note
that the
three underlayments comprising the acrylic emulsion binders in the non-skid
layer also
pass the minimum adhesion requirement. However, these underlayments exhibit
poor
wet skid resistance as noted in example 2because these binders are water-based
and
comprise a surfactant. These binders have poor wet adhesion to the support
sheet. It is
believed that the surfactant also lowers the surface tension of water on the
wet surface
which contributes to poor wet skid resistance.
Table 2
Binder Trade Name Binder Type* Avg. Coating
Load Volume
(ph)
(cc/ft2)
Elastotac H130 hydrocarbon resin 1_9 2.0
Gilsonite 0.1 3.3
Neoprene Chloroprene rubber 1.9 1.0
Butyl rubber 3.4 0.9
Acronal S400 acrylic emulsion 2.3 4.0
Acronal A3234 acrylic emulsion 1.2 2.8
Acronal V275 acrylic emulsion 1.9 4.1
SEBS PSA 3.3 1.6
*53 percent filler, CaCO3, by volume for all formulations
Example 4
[0085] For embodiments comprising a filled textured binder texturing may be
observed via scanning electron microscopy SEM. SEM photomicrographs were
recorded
for a membranes comprising a woven polypropylene support sheet coated with
binders
comprising an SEBS adhesive filled with CaCO3. The volume fraction of filler
was
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varied between 53 percent and 27 percent by volume. See Figs 7A, 7B, and & 7C
for
non-skid coatings comprising 53 percent, 38 percent, and 27 percent filler,
respectively.
Note that texturing may be observed even down to 27 percent by volume of
filler.
23
