Note: Descriptions are shown in the official language in which they were submitted.
711
Background of the Invention
Field of the Invention
The invention is directed to a process for manu-
facturing floor covering material and, more particularly,
to a process for the mechanical embossing of a pattern on
a floor covering material.
Description of the Prior Art
U.S. Patent No. 3,741,851 discloses a process
for making a foam vinyl floor covering. A printed color
pattern or design is provided between a foam resin layer
and a transparent resin wear layer. Embossing is carried
out relative to the transparent resin layer and the em-
bossing is carried out in register with the printed pattern.
U.S. Patent No. 3,176,058 is directed to an
apparatus for embossing sheet material. Cooling means are
provided to cool either one or both sides of the sheet
material prior to embossing.
U.S. Patent No. 3,305,419 is directed to an
apparatus for embossing a foamed backed polyurethane sheet.
Surface heating is carried out to heat only the surface to
be embossed so that there is no damage to the underlying
,foam layer.
Finally, U.S. Patent No. 3,196,062 is directed to
a process wherein cooled embossing rolls are utilized to
provide an embossed pattern on a sheet material which is
composed of a foamed thermoplastic resin base and a
thermoplastic resin top coating. Surface heating of the
thermoplastic resin is carried out just prior to embossing.
Summary of the Invention
In the inventive process herein, the expansion
of a decorated foam is completed in an earlier step in the
711
same manufacturing process in which the embossing is to be
carried out. In other words, the embossing operation is
carried out at the end of the processing line which forms
the expanded foam product. The expanded foam sheet product
is carried on a backing, but does not have any fused or cured
wear layer on the surface of the foam to be embossed. The
surface of the foam to be embossed is maintained at its high
surface temperature, while the backing of the sheet and the
foam adjacent thereto may or may not be cooled. Appropriate
guide structures and controls feed the backing-foam layer
structure into an embossing structure which will place an
embossed pattern on the foam layer in registry with a printed
design on the surface of the foam layer. The embossing
structure has a "bottomless" embossing roll configuration and,
therefore, will cause deep embossing in selected areas in
registry with the printed design, but will not contact those
areas which end up as the raised areas of the finished product.
In order for the raised areas of the finished product to have
some embossed effect, an embossed texturing roll is incorporated
in the guide apparatus to provide a texturing of the raised
areas of the finished product. Consequently, two-stage emboss-
ing is carried out with the first stage embossing providing
only texturing to the raised areas of the foam, while the second
stage embossing provides the deep embossing which forms the
embossed configuration of the finished product in register with
a printed design of the finished product. After the product
has been embossed, it is then provided with a wear layer coat-
ing which will be subsequently fused or cured.
Thus, in accordance with the present teachings, a
process is provided for embossing a web of material when
the material is composed of a carrier and a foamed material
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layer positioned thereon, the foamed material layer having on
the upper surface thereof a decorative pattern printed thereon
the composition structure being in the form of a web which is
heated to a temperature of about 250F to 350F. The process
which is provided comprises deeply embossing in a pattern the
embossable foamed material layer of the web with a "bottomless"
embossing means to emboss deeply a portion of the web to form
depressed areas therein while at the same time not contacting
or embossing the raised areas of the web between the depressed
areas of the web. Laterally guiding the web to the embossing
means so as to provide a registry of the deeply embossed pattern
with the printed pattern in a direction transverse to the
direction of the web movement. The registry of the deeply
embossed pattern is controlled with the printed pattern of the
web so that the two patterns will be in registry and wherein the
web, prior to the deep embossing by the "bottomless" embossing
means is engaged by another embossing means which embosses a
surface texture to a substantial portion of the embossable
foamed material layer and particularly those portions of the
foamed material layer which will not be engaged by the "bottom-
less" embossing means.
This invention permits the manufacture of a laminar-
flooring material with the incorporation of designs and/or
textures having fine details as well as more rounded
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7~1
and deeply embossed relief areas in register with pre-
determined portions of a decorative pattern on a foam layer.
Brief Descrip-tion of the Drawing
Fig. 1 of the drawing is a schematic showing of
the process for carrying out the invention herein; and,
Fig. 2 is a cross-sectional view of an inter-
mediate floor covering product made by the process of the
invention herein.
Description of the Preferred Embodiments
The invention herein is an improvement over the
process for the manufacturing of the product of U.S. Patent
No. 3,741,851 and U.S. Patent No. 3,655,312 and that set
forth in Canadian Patent Application Serial No. 248,946.
In the above-mentioned patents, the oven 18 shown in
Fig. 2 of U.S. Patent No. 3,741,851, serves to fuse the
resin materials and decompose the blowing agent uniformly
throughout the area of the product. Thereafter, the web is
passed while still hot, for instance while at a temperature
of from about 225F. (107C.) to about 325F. ~167C.), to
an embossing structure. The invention herein deals with a -
modification of the structure of U.S. Patent No. 3,741,851
in the area between oven 18 and the point where there is
the embossing structure of the patent. The invention
herein utilizes the inventive apparatus of the abovementioned
copending application, but involves the use of that apparatus
on a foam material which is not provided with a wear layer
coating.
Herein, the warm foam web 2, which would mote from
the oven structure 3, passes around a conventional guider
structure 4 which maintains the registry of the printed
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pattern of the web with the embossing roll pattern in a
direction transverse to the direction of the web movement.
The guider structure is composed of two guide rolls 6 and 8.
The back of the web will pass over roll 6 and then the web
face will pass under roll 8, with the roll surface in contact
with the surface of the web to be embossed. The surface
structure of this roll 8 will be further described below.
This roll 8 is usually maintained at a surface temperature
of about 85F. to 125F (29C. to 52C.). The assembly 4
is a commercially available "Xamberoller which i~vo-~es
two angled guide rolls on a carriage mounted for transverse
movement. The transverse guiding of the sheet is carried
out through the use of the "Kamberol1erTMn structure, and
this structure is disclosed in U.S. Patent Nos. 3,024,955
and 2,797,091. The only difference between the guider
-structure disclosed in the patents and that of this application
is in the surface configuration of roll 8 herein and that
point will be discussed below. The transverse guiding is
used so that the pattern edge of the sheet will be main-
tained in a certain relative position to the embossingroll pattern farther down the processing line to provide
registry in a transverse direction of the embossing roll
- pattern with a printed pattern on the web 2.
The web may then pass over a roller 10, which
may be a back wetting structure such as that set forth
in United States Patent~4~076,867
and e~titled "Multilevel Embossing of
_ .
Foamed-Sheet Materials". Under some circumstances, the
cooling feature of roll 10 may-be utilized, and in other
circumstances, the cooling feature of roll 10 is not
needed and, therefore, roll lQ need only be a steel
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transport roller. The particular condition of roll 10 is
not eritical to the invention herein. Under some cir-
eumstances, a "Teflon eoated roller 12 may be utilized to
provide additional heat to the top surface of the web to
eompensate for heat loss which may occur as the web~is
moving through ambient air from the oven 3 towards the
embossing structure 14. It is obvious that the roll 12 must
not be heated to the point, nor supply sufficient heat to
the upper surface of the web 2, to alter the embossed sur-
face configuration of web 2 at the point of engagement byroll 12.
An embossing structure 14, composed of a back-up
roll 16 and an embossing roll 18 will engage the web to
provide deeply embossed relief areas. The web usually is
embossed almost as soon as it comes in contact with the
steel back-up roll 16. Under some eircumstances, for example,
thiek foam produets, it may be desirable to move the em-
- bossing roll 18 to a position underneath of roll 16 (see -
18'). Under this set of circumstances, the web will be
partially wrapped around the steel back-up roll 16 before
the embossing is earried out by the embossing roll 18' in
its altered position. When embossing is carried out with
the embossing roll 18' underneath of the back-up roll 16,
the baek-up roll 16 will be eooled by chilled water to a
surfaee temperature of about 75F. to 100F. (24C. to
38C.) and will function to further eool the backside of
the web and stabilize the foam prior to the time that embossing
is earried out. Therefore, the steel back-up roll 16 is
funetioning both as a eooling drum and as a baek-up roll for
the embossing roll 18'. The embossing whieh is carried out
at this point will be through the use of a "bottomless"
10~il~711
embossinq roll. This structure will be very similar to
that structure disclosed in U.S. Patent No. 3,741,851. The
embossing roll 18 will contain valleys 19 which are con-
siderably deeper than the total thickness of the embossable
surface of the web 2, but are usually 0.100 inches (.25 cm.)
in depth (see Fig. 2). The embossing roll will be kept at
75F. (24C.) surface temperature.
The web 2, as will be described below, will be
composed of a backing of about 0.028 inches (.07 cm.) thick.
Over this will be placed a foam layer of about 0.035 inches
thick (.09 cm.) thick. The total thickness of the material
being embossed will be 0.063 inches (.16 cm.), which is
substantially less than the above-described valley depth of
the embossing roll 18. Consequently, when roll 18 is
providing the deep embossing on the upper surface of the
web 2, only the raised areas of the embossing roll 18 will
enaage the web 2. The valley areas 19 of the embossing roll
18 will not contact the upper surface 25 of the web.
Since the product that has been embossed is basically
an expanded foam, carried on a backing layer, there is a need
to provide some type of wear surface to the embossed pro-
duct so that it can better serve as a floor covering. Con-
sequently, the embossable surface, after embossing, is fed
around guide roll 26 to place the embossed surface in a
generally horizontal plane with the embossed surface facing
upward. Means 28 will then provide a wear coating to
the embossed surface. The coating may be applied by a curtain
coater, a roll coater, spray means, or any other convenient
means which will provide a thin wear coating overlying the
embossed surface. U.S. ~atent No. 3,828,725 covers a
curtain coating method which can be used in the application
of a polyurethane coating to a moving embossed foam. The
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711
sheet with the wear layer is then passed to a heating
means 30 which will either fuse or cure the wear layer on
the embossed foam surface.
Since there is a need to register the embossing
pattern of roll 18 with a printed pattern on the web 2, there
must be control of the embossing roll pattern relative the
printed pattern to get registry between the two patterns.
This will require registration along the machine direction
and this registry along the machine direction, which is in
the direction longitudinally of the sheet movement, is
maintained in the same manner as set forth in U.S. Patent
No. 3,655,312, Column 5, line 53, to Column 6, line 43. The
technique of U.S. Patent No. 3,694,634 and U.S. Patent No.
3,741,851 can be adopted herein for machine direction
registry also. At this point, it should be noted that
registration controls, both across the machine direction and
along the machine direction, are necessary to secure a
commercially acceptable product with registration between the
embossed pattern and the printed pattern, but such controls
are not a part of the invention herein, since they are
conventional in the art.
The essence of the invention herein ~s in the modi-
fication of roll 8 of guider structure 4. The surface of
roll 8 is provided with a textured or design carrying con-
figuration. In e~fect, roll 8 is being used as an embossing
roll which will place shallow patterns on the upper surface
of the web 2. The pattern placed on roll 8 could be of a
certain specific design, or it could simply be an irregular
dimpled surface used simply to provide a texturing to the
upper surface of the web 2. Roll 8 will have an embossing
surface or texturing which will have a difference of
0.015~0.030 inches (.04 cm.-.08 cm.) between the raised
10~711
areas and valley areas of its embossing configuration. This
roll 8 will be kept fully impressed against the web surface.
The roll 8 will be kept at a temperature of 85F.-125F.
(29C.-52C.) with the web surface at 275F.-325F. (135C.-
163C.). Due to the positioning of rolls 6 and 10 with
the web 2 passing thereover, the web 2 will be held tightly
in engagement with roll 8 so that roll 8 will be able to
provide a textured embossment to the upper surface of web 2.
The depth of embossing typically obtained during this overall
embossing step is 0.012 inches (.03 cm.) due to spring-back
in the material. As the textured web moves to the embossing
means 14, the "bottomless" embossing roll structure 18 will
not disturb the texturing on the raised areas of the web
wherein deep embossing is not carried out.
Referring now to Fig. 2, there is a cross-sectional
view of a portion of web 2. The upper surface of web 2 is
to be embossed and this is the upper part of foam layer 22.
Roll 8 will provide surface texturing 24 on the total surface
of the embossed product and this appears on the raised
areas of the embossed product after the "bottomless"
embossing roll 18 has produced the deep embossing 26. In
addition, the deep embossing 26 will be placed on the web
without the em~bossing roll 18 disturbing the original texturing
24 that roll 8 had previously placed on the web. The
texturing 27 will even appear in the valley areas 26 of
. the final embossed product. The areas 26 can be embossed to
a depth of 0.020 inches (0.05 cm.) while still retaining the
texture 27.
It is possible that the material of U.S. Patent
No. 3,741,851, without its wear layer, could come from the
oven 18 of that patent and pass through all
of the apparatus of that patent with only one slight
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108~711
modification in that apparatus to yield the product of
Fig. 2 herein. In the structure of U.S. ~atent No.
3,741,851, a "Kamberoller , a lateral guide structure, would
be utilized and the second roll thereof would be provided
with texturing as roll 8 herein. In the structure of
U.S. Patent No. 3,741,851, there is the indication that only
25% of the total sheet area can be embossed, whereas, with
the structure herein, it is possible to emboss, by the use
of both texturing and deep embossing, the full 100% sheet
surface area.
A typical example of a product which may be made
by the invention herein is below described. The product
will be made by placing a plastisol on a carrier web such as
that disclosed in U.S. Patent No. 2,759,813. The following
plastisol is prepared by thoroughly mixing the following
ingredients:
- Ingredients Parts by Weight
Poly(vinyl chloride) 100
Dioctyl phthalate (plasticizer) 49.55
Octyl epoxy tallate (stabilizer) 5.0
Titanium dioxide 3.6
Azodicarbonamide (blowing agent) 2.3
Talc 0.6
Zinc octoate (blowing agent activator) 1.95
This above plastisol is applied to the above-
described carrier which is a coated beater-saturated asbestos
sheet having a thickness of about 0.028 inches (.07 cm.).
The plastisol is applied with a reverse roll coater to a
wet thickness of 10 mils (.03 cm.). The plastisol-coated
30- backing is gelled in a hot air oven for one minute to an
exit temperature of 270F. (132C.).
-
_ g _
711
The sheet is then coo1ed and a printed design isplaced thereoll. The printed design may be of any particular
pattern and could be of the same pattern as that shown in
Fig. 3 of U.S. Patent No. 3,741,851. Inks are prepared by
thoroughly mixing the following ingredients:
Ingredients Parts by ~7eight
Vinyl binder 33.0
Pigment 12.8
Cellosolve acetate 1.6
2 Nltropropane 50.0
- Isopropyl acetate 1.0
Alkyl alcohol aryl polyether1.0
Inks of various colors based on the above formula
are applied to the gelled plastisol sheet described above
utilizing the printlng cylinders of a conventional roto-
gravure printing press. The printing cylinders are run in
a normal manner producing the design that is printed in
register. The inks are dried by subjecting the printed sheet
to warm air impingement supplied by the enclosed drying zones
of the press. The inks are not critical to the invention
herein, but simply need be inks which are capable of adhering
to and drying on the plastisol above described.
At this point, the plastisol may be subjected to
further heat in a hot air oven for 1 minute to an exit
temperature o~ 375F. (191`C.) to complete the decomposition
of the blowing agent in the gelled plastisol coat to convert
it to a foamed layer. It is also possible to eliminate
this second heating operation by passing the plastisol coated
backing through a hot air oven and almost completely decompose
the blowing agent prior to the printing operation. In
these circumstances, the hot air oven would be utilized for
1 minute to an exit temperatu~e of 375F. (191C.) to
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lOli~711
~roduce the fully foamed product which would then subsequently
be printed. Re~eating for embossing can be done later iust
prior to embossing.
After the printing of the gelled plastisol has been
carried out and this structure has passed through an oven
to complete the decomposition of the blowing agent to convert
the plastisol to a foam layer, embossing can be carried out.
The printed and foamed layer will leave the oven at about
300F. (149C.). Coming from the oven, the above-
described composite sheet composed of a backing layer, a foamlayer and a printed design thereon will constitute web 2
of the drawing. The web 2 will then be processed through
the apparatus as above described to provide surface texturing
with roll 8, to provide deep embossing with roll 18, and then
a wear coating through the use of elements 28 and 30.
There is now provided after embossing a product
- which is composed of a backing and a foam layer which has
embossing therein in register with the design which is printed
on the foam. Such a product might be acceptable for use as
a wall covering, but certainly would not work satisfactorily
as a floor covering unless it had some type of wear layer
applied thereto. ~eb 2, now fully embossed, will then pass
by a coating apparatus 28 which will provide a wear layer
material to the embossed web 2 and then the web will pass
through heater 30 which will fuse or cure the wear layer just
applied. The wear layer used may be any of the conventional
wear layer materials which have been utilized in the floor
covering art. About the only limitation that exists relative
the wear layer is that the fusion or curing temperature of
the wear layer must be low enough that the temperature utilized
will not cause destruction of the foam layer or relaxation
of the embossed pattern in the foam so that the embossed
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10~ 7:11
configuration deteriorates. If the fusion or curing of the
wear layer is carried out under the circumstance where the
total web is heated, then the temperature of fusing or curing
clearly must be low enough so that deterioration of the foam
does not occur. If the curing or fusion of the wear layer
is carried out by a surface heating which is directed just
to the wear layer, then higher temperatures may be utilized.
By higher temperatures is meant temperatures which would
normally be expected to affect the foam. However, these
higher temperatures are only utilized for a short period
of time and are applied primarily to the wear layer coating
and are not permitted to cause a raising of the foam level
temperature to a point where the foam will be affected by
the temperature.
Example 1
Typical of a clear poly(vinyl chloride) wear layer
coating that can be utilized is:
For~ula 1
Ingredi-ents Parts by Weight
Poly(vinyl chloride) copolymer100.00
Dioctyl phthalate (plasticizer) 60.00
Octyl epoxy tallate (stabilizer) 3.00
Barium cadmium zinc (stabilizer) 3.00
This wear layer composition is applied to a fully
embossed web 2, which is 0.060 inches (.15 cm.) in thickness,
by a conventional curtain coating apparatus 28 to a film
thickness of 0.006 inches (0.015 cm.). In this case, the
curtain coater head cavity described in U.S. Patent 3,828,725
does not ~ontain, when used herein, the flow restricting
device due to the higher viscosity and solids levels of the
above plastisol wear layer formulation. The wet coating
can be applied in a continuous manner after the foam layer is
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10~bt711
embossed, as is shown in Fig. 1, whereby the wear layer is
fused utilizing a hot air heater 30 which is directed towards
the top surface of the web 2. Typical fusing conditions
require hot air impingement for 1/2 minute with the air at
500F. (260C.). Alternately, the embossed foam 2 can be
cooled by rolls 32, bypassing coater 28 and heater 30 and
wound onto spindle 34. At some future time, and possibly in
another location, the wear layer coating can be applied
to the embossed foam by a similar coating apparatus 28 and
fused by similar types of surface heaters 30. In the case
of the clear poly(vinyl chloride) wear layer applied in the
manner as described above, a resilient floor covering material
is produced which has a depth of embossing of 0.010 inches
(.025 cm.) after the wear layer is fused.
Example 2
Example 1 was repeated wherein a thin adhesive
coating of Formulation 2 below was applied to the 0.006
inch (0.015 cm.) fused plastisol wear layer of Example 1
and dried with heater 30 using 140F. (60C.) air. In
this case, a fully embossed 0.080 inch (.203 cm.) foam was
used in the experiment.
Formula 2
Ingredients Parts by Weight
Poly(vinyl chloride) solution grade 30.00
Xylene 21.00
Methyl ethyl ketone 48.64
Thio-tin (stabilizer) (Thermolite-31) 0.36
Onto this layer was applied a clear 2 mil (dry)
coating of a curable polyurethane utilizing the invention
described in U.S. Patent 3,828,725. The polyurethane
coating is a 62.5/37.5 xylene/resin solution containing
catalyst. The polyurethane coating can also be applied by
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711
eMploying conventional airless spray equipment. Criticality
does not particularly rest in the method by which the wear
layer coating is applied. Heat is applied in the form of hot
air impingement utilizing heater 30 for a period of 3
minutes at 275F. (149C.) air temperature. The last coating
applied is the wear layer surface of the resulting floor
product which will be formed. Polyurethane coatings are
applied to secure a product which will retain a hard, high
gloss surface and eliminate the need for subsequent waxing
by the user of the floor.
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