Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to road surface marking tape
materials for use on roadway pavements so as to provide a traffic
regulating indicium thereon, such as traffic lane dividing lines,
road lane edges defining lines and so on. More particularly, this
~nvention relates to prefabricated tape materials having wear-re-
sisting properties, and principally (as far as the invention is con-
cerned) anti-skid properties, provided by the ract that the material ;
has a smooth highly wear resisting planar surface layer and a plural-
ity of hard crystalline particles at least some of which include an
upper portion extending outwardly from the upper face of said layer
to impart good anti-skid properties to said face for vehicle traffic
safety. The tape material concerned with the invention being also of
the kind designed to be applied on and secured to the roadway pave-
ment by means of lower "primer" layer best suitable for its anchorage
with the pavement.
This art is a well known and worked one and several
improvements had been made thereto. A number of Patents had been
issued to the present applicant thereabout. Reference is herein made
to the U.S. Patents Nos. 3,872,843 and 3,935,365 (corresponding to
20 British Patent Specifications No. 1,359,036 and respecvively
1,463,681 and to published German Patent Applications P 21 30 529.3
and P 24 o3 398.5) for more complete acknowledgement of such prior
art and of the problems concerned therewith.
One important problem descends from the most desirable
anti-skid property of the material. The upper surface of the tape in
service is firmly engaged by the vehicle wheel treads and therefore
powerful thrusts occur to be applied tan~etially on the said surface
(the term "tangentially" refers to the wheel tread where contacting
the surface, that is directed in the plane defined by said surface),
30 extremely powerrul forces can be for example originated by a heavy
and/or fastly travelling vehicle engaged in an emergency braking or
by the centrifugal force during a curve. These thrusts tend to
--1-- ,~~'.D
displace the tape in the direction of the force, that is cause the
tape material to "slide" on the road pavement, detaching sald tape ~-
from said pavement.
On the other hand such powerful thrusts are applied on the
tape surface at a rather small surface area thereof, that is at the
wheel tread tape surface interface- Now, the tape material i5 `. .
secured to the (generally bitumen based) roadway pavement by means Or
an essentially plastic composition, even if the primer layer com-
prises completely hardened bituminous components. The resistance to
said tendency of hori~ontally displacin~ the tape, under said thrusts
can provided at the tape material-road pavement interface (nore ,;
properly, interlayer) at a very greater interfacial area.
- In the pratical service of said road marking tapes, as
known to those skilled in the art, a tangentially applied powerful
thrust can cause and frequently causes a localized damage to the ~tape
material, which locally flakes off and wrinkles up, and sometimes is
torn apart.
Complemental problems concern the desirable provision of
tape material of small overall thickness (both for economy reasons
and for limiting its overall height or protrusion from the actual
road pavement surface) and the difficulty and hard and fatiguering
operation of removing, when necessary, a properly applied and secured
marking tape from the road pavement, for example when the location of
the marking is to be modified.
It is therefore an ob~ect of this invention to provide a
new and improved tape material which is not subJect to the above and
other ob~ectlons. In other words, it is an ob~ect of this invention
to properly and satisfyingly solve the above and other problems.
Accordiny to the present invention, there is provided
a multi-layer road surface marking tape material of the type
comprisin~, when applied on and secured -to a roadway pavement,
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iO ~
an upper wear-resisting and anti-skid layer and a lower primer
layer for firm attachment to the pavement;, characterized by
comprising, between the upper and lower layers, at least an
intermediate relatively thin, pliable~essentially inextensible
and tensionally resistant intermediate layer compatible with
and intimately connected to both the layers for distributing
and transferring over a large primer layer-roadway pavement
interfacial area horizontally clirected stresses trangetially
applied to the anti-skid upper layer at localized upper layer-
vehicle wheel treads interfacial areas.
According to an embodiment of the invention, tne
said intermediate layer consists of a film of highly tensionally
resistant polymeric resin. Preferably, said intermediate layer
consists of a polyester film from 0.02 to 0.3 mm thick.
According to another embodiment of the invention,
the said intermediate layer consists of a highly tensionally
resistant resin impregnated non-woven fibrous structure. Prefera-
bly, said fibrous structure is impregnated at its portions
adjacent to the upper and respectively to the lower layer by
the same compounds comprised in said layers.
The said non-woven structure consists of fibers
made
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of any suitable fiber forming synthetic composition capab].e of
providing essentially inextensible and highly tensionally resist-
ant fiber, such as polyester. The same structure can also be
made of glass fibers. In such occurence., the fibrous structure
can be suitably impregnated with a synthetic rubbery or elasto-
meric composition for minimizing the brittleness of the fibers. ~-
According to a complemental advantageous reature
Or the invention, the new tape material Or the invention can be ` ~ .
easily removed from the road pavement at the extent necessary for ~ -
obliterating the marking, by inserting and displacing a heated
blade at the level of the lower or of intermediate layer, when
made of heat meltable material) for separating the marking forming
upper layer from the roadway pavement contacting lower or primer ..
layer. The said upper layer can be recovered for subsequent ~:
application and use.
These and other features and advantages of the :
invention will be made best apparent from the following detailed
description of preferred embodiments thereof, reference being
made to the accompanying drawings, wherein:
FIG. 1 is a somewhat diagrammatical, fragmentary,
partly sectional perspective view of a tape materi.al according ~.
to the invention, applied on and secured to a roadway pavement; .
FIG. 2 is an exploded view of the components of the -.-
material of FIG. 1, the intermediate layer forming component . .-.
being shown to illustrate two alternative embodiments thereof;
FIG. 3 is a diagrammatical side view and partly a !~ :
sectional view of a mechanism adapted f.or remov:lng the material
from the roadway pavement;
FIG. 4 is a sectional view illustration a combination .-~
of certain components of the structure, before and after the
assembling thereof;
FIG. 4A is a view similar of that of the righthand .
. . .
part of FIG. 4 and illustrates a modified combination; and
FIGS. 5, 6, 7 and 8 are views similar to that of
FIG. 4 and illustrate further modified combinations, including
thermoplastic components preferably comprising bituminous and/or
epoxy-bituminous components.
In its broadest aspect, the tape material according
to the invention comprises the combination and the arrangement
of components as shown in FIG. 1. When properly laid on and ~ -secured to the surface Or a rodaway pavement generally indicated
at T, by means of a "primer layer" (this term is of current use
in the art, as being conventionally referred to a layer which
is formed on the pavement surface, preparatory to laying the ~
tape material thereon) of substantially bituminous nature, the -
road surface marking material gas has an upper face 16 which defines ~ -
the sign. Said lower or primer layer is generally indicated at P.
Such upper race 16 is embodied by an upper layer S
having a high resistance to wear and formed by a higly resistant
polymer, such as a polyester or a polyamide resin, and preferably
of a polyurethane resin, and consists Or a layer of thickness
preferably comprised between 0.4 and 1.0 mm. This upper face 16
is made "anti-skid" by embedding into said layer hard particle,
preferably crystals or microcrystals of a substance having a
hardness at least Or and preferably greater than 6 on the Mohs'
Hardness Scale, such as of quartz, aluminum sllicofluoride,
aluminum sesquioxide and preferably carborundum. Some partially
protruding particles are diagrammatically shown and indicated at
20 in FIGS. 1 and 2.
The upper layer can be also provided, according to the
art, with light retroreflective elements, generally spheroidal,
part of which are also shown and indicated at 22.
According to the invention, the said upper layer S
- and the said lower or primer layer P are interconnected by an
.. ~ . - :. .
,
intermediate layer which is pliable ~for best adaptation of the
tape material to the road pavement T unevenness, and for admitting
the winding of the material into coils or bobbins, ror storage
and/or transportation), essentially inextensible and having a
great reslstance to tension. Such intermediate layer can comprise
a sheet of suitable substance, such as indicated at 24, or
comprise a non-woven fibrous structure, as indicated at 24~ in the
righthand portion of FIG. 2.
The described multi-layer structure comprises in at
least one of its layers thermoplastic components. This provision
can be made use of for easily detaching the tape from the road
pavement by making use of a simple apparatus such as illustrated
in FIG. 3, and generally indicated at 30. Such apparatus
comprises a truck which can be displaced in direction A along
the tape to be removed. The frame structure 32 of said truck `
supports a blade-like tool 34 positioned for engagement and
lengthwise insertion into and below the tape material, at a level
intermediate its upper layer (generally indicated at S in FIG. 3, ~ `
for simplicity) and the lower pavement engaging face of the primer
layer P.
'.,:. '
The blade tool 34 is heated for example by a burner 36
and the upper layer portion of the detached tape material can be
pull up along a sloping support 40 by a recovery bobbin 42. Said
upper layer portion, generally indicated at Ss, thus recovered,
can be further made use of. This provides a substantial saving
because the upper layer Sp is as a matter Or fact the most costly
component of the product, in particular when provided with a
substantial amount Or corundum crystals and~or o~ retroreflective ~- -
elements. The apparatus is complemented by the provision Or a fuel
source, such as a bottle 38 containing liquified gas and, ir desired,
with a source of power, such as an internal combustion engine3 for
driving the truck and/or rotating the mandrel about which the bobbin
^~44~J~f~
42 is wound.
Various arrangements and interactions of the layers in
a multi-layer structure in which the intermediate layer comprises ~ -
a non-woven fibrous impregnated structure will be now briefly
described with reference to FIGS. 4 to 8 inclusive. Such arrange-
ments comprise preferably but not exclusively a fibrous structure
formed with glass fibers.
It has been ~ound that binder agents consisting of
bituminous or epoxy-bituminous compounds are well compatible with
and intimately penetrate into such fibrous structures. Upon
~uxtaposition of a layer Sp of resinous substance, such as polyure-
thane, on a fibrous layer, another substantial interpenetration
occurs. This greatly improved the bond between the various layers.
Further, the fibrous intermediate layer ls generally
preliminarily impregnated preparatory to the layer ~uxtaposition,
and the various still liquid or viscous and not yet set compounds
either forming the upper layer and/or lower layer and impregnating
the intermediate viscous layer intermix at the layers' lnterfaces
and thereabout for further improving the bond and the structural even
if heterogeneous unitarity Or the multi-layer structure.
Thus, as diagrammatically shown in FIG. 4, the ~uxtaposi-
tion of the components Of the upper layer Sp and or the intermediate
non-woven layer Snt yields to forming of a mixed (and possibly a
chemically interreacted) interlayer Sp~Snt improving the bond.
FIG. 4A diagrammatically indicates that the upper layer Sp can
be preliminarily formed as a calendered sheet and then coupled to
the fibrous layer under pressure and vulcanlzation process.
The ~iagram of FIG. 5 visualized the interlocation Or
- a sheet F of a flexibilizing and/or waterproofing agent between the
upper layer forming component Sp and the non-woven structure Snt.
In the compound product (lefthand part of the FIGURE) a plurality
Or interlayers is therefore formed, such as generally indicated at
--7--
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Sp~F and F+Snt. Correspondingly, as indicated in the diagram Or
~IG. 6, an interlayer of crossed impregnation PtSnt can be formed
between the impregnated fibrous layer Snt and the primer layer
P. FIG. 7 depicts the formation of two interlayers Sp~Snt and
F~P resulting from the interposition of the said ~lexibilizing
and/or waterproofing agent F between the non-woven layer and the
primer layer P. FIG. 8 ~inally illustrates a deep intercrossed
impregnation which involves nearly the entire thickness of the
fibrous layer Snt, by part of both the compounds Or the upper layer
Sp and the primer layer P. The substances and compounds adapted
for providing such interrelations will be commented in the following
Examples. ;
Example 1
`,~ -
This Example refers to the manufacture of a multi-layer
tape material including an intermediate layer 34 consisting of a
resinous film from 0.03 to 0.3 millimeters thick. This material
corresponds to the combination shown in the lerthand portion of
FIG. 2. In this structure it is critical that the upper layer Sp
will be intimately and firmly bonded to the intermediate film. ``
Assuming that such film is made of a polyester resin, the wear
resisting upper layer can be made Or a polyester composition as -~
follows tin percent by weight):
Polyester resin (such as "Dynapol S 206", by
Dynamit Nobel A.G.) 56%
Methylethylketone 34
Titanium dioxide 10% "~
Example 2
This Example refer to rorming a primer layer well
adapted to provide a firm bond with an intermediate layer as above,
by a two-component (A and B) composition, as follows (in parts by
weight):
''A" Solid oxidized bitymen parts 17
:
~ -8-
Epoxy Tar (tar for e~p~oxy resins) parts 10
Synthetic rubber (such as "R.T.V.
Rubber", by Polysar Canada) parts 24
Colloidal silica (such as "Aerosil" parts 2
Epoxy resin (such as "Araldite 250",
by Ciba) parts 42
B'' Solid 40/50 bitumen parts 17
Epoxy Tar parts 15
Cresylic Acid parts 5
Polyamide resin tsuch as "Versamid 140") parts 36
Kaolin parts 27
Accelerator for the Epoxy Resin Or
Component "A" (such as "D.M.P. 30") parts 2
The follosing Example refer more specifically to the
manufacture Or tape material comprising a fibrous intermediate
layer.
In general, the said fibrous intermediate layer comprises
a non-woven fabric of weight comprised between 50 and 250 g/sq.meter,
which is impre~nated and sub~ect to uniform pressure, by calendering
for example, for providing a structure preferably of thickness less
than one millimeter; a thickness comprised between 0.3 and 0.6mm is
preferred, so that the coupling of the upper layer (which includes
abrasive and retroreflective elements) and on the intermediate layer
forms a multi-layer of thickness generally slightly above one
millimeter. This feature is advantageous in view of the cost,
pliableness and lightweight of the material to be laid on a prepared
primer layer.
The impregnation of the fibrous structure is preferably
made by making use of impregnating compound having, when completely
set, a substantial resiliency. These compounds comprise preferably
but not~critically epoxy resins, epoxy-urethane resins epoxy-nitrile
resins, polyester resins and, more preferably, combinations of epoxy
-,: , ' ' . ' '-,,.;' , :. ' ,~ ' '
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: : . :.
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resins and of synthetic in particular nitrile rubbers. The
impregnating compound, added to suitable accelerator agents, is
applied as a solution and heat processecl, when the impregnation has
been completed, to provide a stable waterproof and highly resistant
structure.
Example 3
A non-woven fabric Or polyester fibers weight 75 g/sp.
meter and resistlng 10 kg/cm (perpendicularly to the force) is
impregnated up to weight Or 160 g/sq~m with the f ollowing cornposition
(parts by weight):
Nitrile rubber (such as "Chemigum N 60o" by Goodyear) 100
Epoxy resin (such as "Epon 828", by Shell) 100
Zinc oxide 5
Stearic acid 1
Sulphur 3.5
Accelerator (DMP 30) 1.5
Accelerator (benzotiacyldisulphate) 1.5
Titanium dioxide 7-5
This composition is soluted into a solvent consisting Or
250 parts Or methylethylketone peroxide and 250 parts Or toluene,
and sub~ected to a 10' treatment at 160C. The thus impregnate~i and
processed fibrous structure resists to tension Or 20 kg/cm and has
excellent waterproof` and water resistant properties~ ~ -
Example 4 ~
The bondirlg Or a structure obtained according to the ~ ~ -
above Example 3 with a polyurethane upper layer, the surface Or said :-
structure can be treated with a mordanting composition consistin~, -
of (parts by weight): -
Epoxy resin (such as "Epon 828" by Shell) 70
Polybutadiene, or
Butyl rubber ~such as "Polysarl'Canada) 30
Polyamide ~such as "Versamin 125", by Scheringi) 40
-10-
Titanium dioxide ~o ~ 35
Dibasic lead phthalate 5
Solvent (toluene) 320
Example 5
The twin layer structure comprising the intermediate
layer of Example 3 can be secured to the road~ray pavement upon
applying and doctoring of the pavement surface a primer layer
consisting of (parts by weight):
Butyl rubber (such as "Polysar Butyl 301")100
Oxidized bitumen 15
Zinc oxide 5
Stearic acid 2
Extra-fine clay ("China Clay) 15
Zinc diethylditiocarbammate 3,5
Dibenzylamine 2
Sulphur 2
Solvent (such as "Solvesso 100") 25
Exarrlple ~
The multi-layer prefabricated tape material can be
provided with a compatible primer layer preliminarily applied (such
as by calendering) and secured to the face Or the intermediate layer
opposite to the upper layer.
Such preliminarily applied primer layer can be made by
the use Or the followin~ composition (in parts by Weight):
Butyl rubber (as above) 100
Oxidized bitumen 65
Extra-fine clay (as above) 25
Hydrocarbonic resln (such as "Piccopale 100") 20
Liquid coumarone resin (such as liquid "Cumar",
by Allied) 20
Carbon black 25
Anthracene oil, or tar 20
~`~3~
Example 7
This Example is a modification Or Example 3 and refers ::
to a composition particularly adapted for providing a laminated or
calendered sheet of the impregnating material, such as indicated at -
F in FIGS. 5 to 7, for example. Such composition comprises, in
parts by weight: :
Epoxy resin (such as "~pon 828", by Shell 70 ~ .
Bromine modified butadiene rubber, capable to
cross-link at ambient temperature tsuch as ;
"Polysar RTV" 30 :
Polyamide (such as "Versamid 125", by Shering) 40
Titanoum dioxide 50
Dibasic lead phthalate 5
Toluene 180 `.
Isopropyl alcohol 120
The impregnated structure is heated for 10' at 160C.
Example 8
The use of fiberglass for producing the fibrous structure .: ~
of the inter layer is preferably combined with the use of an - :
essentially resilient compound for forming the upper layer Sp of
FIGS. 4 to 8, such as a polyurethane resin, for m~nimizing the
brittleness of the glass; and forming a deeply compenetrated layer ~ -
~
..: . .
system. The upper layer can be made extremely thin. The -
advantageous provision of the flexibilizing (and waterproofing) .
interlayer forming component F (interlayer Sp~F~ and F~Snt, and also .`
FtP, FIGS. 5 to 7) can be provided by making use of the followin~ v
- composition, in parts by weiFht: `
Polyethylene chlorosulphonate (such as "~Iypalon"~
by DuPont) 400 `
Titanium dioxide 250 ;
Baryte 150 ;
Kaolin clay 150
-12-
Polyester resin (such as "Neoxil") 50
The thus flexibilized and/or waterproofed structures
can be variously formed and arranged, as examplified in FIGS. 5 to 7.
-13- ;
