U.S. patent application number 09/725971 was filed with the patent office on 2002-05-30 for method for assembling a reinforced vinyl-backed carpet.
Invention is credited to Evans, Paul D. JR., Hammel, Wallace J., Mayfield, Dan E..
Application Number | 20020062899 09/725971 |
Document ID | / |
Family ID | 25682263 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020062899 |
Kind Code |
A1 |
Hammel, Wallace J. ; et
al. |
May 30, 2002 |
METHOD FOR ASSEMBLING A REINFORCED VINYL-BACKED CARPET
Abstract
A method for manufacturing a vinyl-backed carpet is described
wherein the carpet is assembled in a single continuous finishing
line. The method includes the application of a vinyl plastisol
reinforcing layer directly to the back of unfinished woven or
tufted carpet material. The method allows the use of a thinner
vinyl layer that results in savings in material, processing steps,
and energy required for curing.
Inventors: |
Hammel, Wallace J.;
(Chatanooga, TN) ; Evans, Paul D. JR.; (Dalton,
GA) ; Mayfield, Dan E.; (Chatsworth, GA) |
Correspondence
Address: |
J. MICHAEL MARTINEZ DE ANDINO ESQ.
HUNTON & WILLIAMS
RIVERFRONT PLAZA, EAST TOWER
951 EAST BYRD ST.
RICHMOND
VA
23219-4074
US
|
Family ID: |
25682263 |
Appl. No.: |
09/725971 |
Filed: |
November 29, 2000 |
Current U.S.
Class: |
156/72 ;
156/334 |
Current CPC
Class: |
D06N 2203/045 20130101;
Y10T 428/23979 20150401; Y10T 428/23993 20150401; B32B 5/26
20130101; D06N 7/0081 20130101 |
Class at
Publication: |
156/72 ;
156/334 |
International
Class: |
A46D 001/00 |
Claims
What is claimed is:
1. A method of assembling a floor covering comprising the steps of:
providing a carpet layer having textile fibers defining an upper
surface and having an opposing carpet layer back surface; forming a
vinyl layer on the carpet layer back surface; and adhering a
backing layer to the vinyl layer, the backing layer having a front
backing surface for adhering to the vinyl layer and an opposing
rear backing surface; wherein the carpet layer is provided as a
continuous sheet and the steps of forming a vinyl layer and
adhering a backing layer are performed on the carpet layer in a
continuous manner in a single carpet finishing line.
2. A method of assembling a floor covering according to claim 1
further comprising the step of applying an adhesive to the rear
backing surface, wherein the step of applying an adhesive is
performed in a continuous manner in the single carpet finishing
line.
3. A method of assembling a floor covering according to claim 2
wherein the adhesive is an oleophobic pressure sensitive
adhesive.
4. A method of assembling a floor covering according to claim 2
further comprising the step of applying a release cover over the
adhesive to prevent inadvertent adhesion of the adhesive prior to
installation of the floor covering.
5. A method of assembling a floor covering according to claim 1
further comprising the steps of: applying a barrier layer to the
rear backing surface, the barrier layer having an upper barrier
surface adjacent the rear backing surface and a lower barrier
surface; and applying an adhesive to the rear barrier surface;
wherein the barrier layer is effective for substantially inhibiting
migration of moisture from a substrate into the backing layer and
for substantially inhibiting migration of backing constituents from
the backing to the substrate.
6. A method of assembling a floor covering according to claim 5
further comprising the step of applying an adhesive to the rear
barrier surface, wherein the barrier layer is effective for
substantially inhibiting migration of backing constituents from the
backing to the adhesive.
7. A method of assembling a floor covering according to claim 1
wherein the carpet layer includes a resin composition layer having
a front resin surface adhered to at least a portion of the textile
fibers and an opposing back resin surface.
8. A method of assembling a floor covering according to claim 7
wherein the carpet layer includes a primary backing to which the
textile fibers are attached, the resin composition layer being
formed so as to lock the textile fibers to the primary backing.
9. A method of assembling a floor covering according to claim 7
wherein the textile fibers are configured as interwoven warp and
weft yarns thereby forming a woven carpet fabric having a traffic
surface and an opposing rear fabric surface, the warp and weft yams
defining interstices therebetween and wherein the resin composition
layer is formed on the rear fabric surface so that a portion of the
resin composition layer occupies at least a portion of the
interstices.
10. A method of assembling a floor covering according to claim 1
wherein the step of forming a vinyl layer includes continuously
moving the carpet layer through a vinyl application station;
depositing a first portion of uncured vinyl material on the carpet
layer back surface; spreading the first portion of uncured vinyl
material across the carpet layer back surface; and establishing a
substantially uniform predetermined thickness of the vinyl
layer.
11. A method of assembling a floor covering according to claim 10
wherein the step of establishing a substantially uniform
predetermined thickness includes passing the carpet layer through
means for removing excess vinyl material and controlling the
thickness of the vinyl layer.
12. A method of assembling a floor covering according to claim 10
wherein the step of establishing a substantially uniform
predetermined thickness includes passing the carpet layer between a
thickness control roller and a base surface in a predetermined
direction, the thickness control roller being configured for
engaging and spreading the vinyl material across the carpet layer
back surface to provide a substantially uniform vinyl layer.
13. A method of assembling a floor covering according to claim 12
wherein the control roller layer has an outer surface, a portion of
which is in contact with the vinyl material, and wherein the
control roller is rotated at a predetermined rate in a direction
such that the portion of the control roller surface in contact with
the vinyl material moves in a direction opposite to the
predetermined direction of motion of the carpet layer.
14. A method of assembling a floor covering according to claim 10
wherein the step of forming a vinyl layer further includes:
applying a scrim sheet over the first portion of uncured vinyl
material spread on the carpet layer back surface; and depositing a
second portion of uncured vinyl material over the scrim sheet
15. A method of assembling a floor covering according to claim 10
wherein the step of forming a vinyl layer further includes: heating
the uncured vinyl material to a temperature above the cure
temperature of the vinyl material to cure the vinyl layer and
permanently adhere the vinyl layer to the carpet layer back
surface.
16. A method of assembling a floor covering according to claim 1
wherein the vinyl layer is formed from a polyvinyl chloride
plastisol material.
17. A method of assembling a floor covering comprising the steps
of: providing a carpet layer having textile fibers defining an
upper surface and having an opposing carpet layer back surface;
depositing a first portion of uncured vinyl material on the carpet
layer back surface; spreading the first portion of uncured vinyl
material across the carpet layer back surface; applying a scrim
sheet over the first portion of uncured vinyl material; depositing
a second portion of uncured vinyl material over the scrim sheet;
passing the carpet layer between a thickness control roller and a
base surface in a predetermined direction, the control roller
having an outer surface, a portion of which engages the second
portion of uncured vinyl material, the control roller being rotated
at a predetermined rate in a direction such that the portion of the
control roller surface engaging the vinyl material moves in a
direction opposite to the predetermined direction of motion of the
carpet layer thereby establishing a vinyl and scrim laminate having
a substantially uniform thickness; heating the uncured vinyl
material to a temperature above the cure temperature of the vinyl
material to cure the vinyl and permanently adhere the vinyl and
scrim laminate to the carpet layer back surface; and adhering a
backing layer to the vinyl layer, the backing layer having a front
backing surface for adhering to the vinyl layer and an opposing
rear backing surface.
18. A method of assembling a floor covering according to claim 17
wherein the carpet layer is provided as a continuous sheet and the
steps of depositing a first portion of uncured vinyl material,
spreading the first portion of uncured vinyl, applying a scrim
sheet, depositing a second portion of uncured vinyl material,
passing the carpet layer between a thickness control roller and a
base surface, heating the uncured vinyl material; and adhering a
backing layer are performed on the carpet layer in a continuous
manner in a single carpet finishing line.
19. A method of assembling a floor covering according to claim 18
further comprising the step of applying an adhesive to the rear
backing surface, wherein the step of applying an adhesive is
performed in a continuous manner in the single carpet finishing
line.
20. A method of assembling a floor covering according to claim 19
wherein the adhesive is an oleophobic pressure sensitive
adhesive.
21. A method of assembling a floor covering according to claim 19
further comprising the step of applying a release cover over the
adhesive to prevent inadvertent adhesion of the adhesive prior to
installation of the floor covering.
22. A method of assembling a floor covering according to claim 17
further comprising the step of: applying a barrier layer to the
rear backing surface, the barrier layer having an upper barrier
surface adjacent the rear backing surface and a lower barrier
surface; and applying an adhesive to the rear barrier surface;
wherein the barrier layer is effective for substantially inhibiting
migration of moisture from a substrate into the backing layer and
for substantially inhibiting migration of backing constituents from
the backing to the substrate.
23. A method of assembling a floor covering according to claim 22
further comprising the step of applying an adhesive to the rear
barrier surface, wherein the barrier layer is effective for
substantially inhibiting migration of backing constituents from the
backing to the adhesive.
24. A method of applying a polymeric material to a textile sheet
having opposed first and second surfaces, the method comprising the
steps of forming a plastisol from the polymeric material;
depositing a first portion of plastisol on the first surface of the
textile sheet; spreading the first portion of plastisol across the
first surface of the textile sheet; passing the textile sheet
between a thickness control roller and a base surface in a
predetermined direction, the control roller having an outer
surface, a portion of which engages the plastisol, the control
roller being rotated at a predetermined rate in a direction such
that the portion of the control roller surface engaging the
plastisol moves in a direction opposite to the predetermined
direction of motion of the textile sheet, thereby establishing a
layer of polymeric material having a substantially uniform
thickness.
25. A method of applying a polymeric material to a textile sheet
according to claim 24 further comprising the step of: heating the
plastisol to a temperature above the cure temperature of the
polymeric material to cure the polymeric material and permanently
adhere the polymeric material to the textile sheet.
26. A method of forming a laminate having a textile sheet with
opposing first and second surfaces, a first polymeric composition
layer adhered thereto, a reinforcement sheet and a second polymeric
composition layer, the method comprising the steps of forming a
plastisol including at least one polymeric resin material;
depositing a first portion of plastisol on the first surface of the
textile sheet; applying a reinforcement sheet over the first
portion of plastisol; depositing a second portion of plastisol over
the reinforcement sheet; passing the textile sheet between a
thickness control roller and a base surface in a predetermined
direction, the control roller having an outer surface, a portion of
which engages the second portion of plastisol, the control roller
being rotated at a predetermined rate in a direction such that the
portion of the control roller surface engaging the plastisol moves
in a direction opposite to the predetermined direction of motion of
the textile sheet, thereby establishing a substantially uniform
overall thickness of the laminate;
27. A method of forming a laminate according to claim 26 further
comprising the step of heating the plastisol to a temperature above
the cure temperature of the polymeric material to cure the
polymeric material and permanently adhere the polymeric material to
the textile sheet.
28. A method of forming a laminate according to claim 26 wherein
the reinforcement sheet is a fiberglass scrim material.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates broadly to the manufacture of
vinyl-backed floor coverings and more particularly to a process of
assembling a floor covering having a vinyl layer intermediate a
woven or tufted carpet layer and a backing layer.
[0002] Carpet is manufactured through a series of separate
processes that are typically carried out on separate manufacturing
lines. A first line is used to produce a carpet material that is
formed either by weaving textile yarns to form a woven layer or by
attaching tufts of textile material to a woven primary backing. In
either case, a thin polymeric locking layer is coated to the
backside. The output of this process is an unbacked or unfinished
carpet material, which is then wound into a roll and transferred to
a second processing line. In the second processing line, a layer of
vinyl material is added to the back of the carpet to fill the voids
in and between the fibers and to provide a uniform surface for
attachment of a backing layer. This vinyl layer is typically formed
by applying an uncured layer of vinyl on a belt, pressing the
unbacked carpet material onto the vinyl sheet and passing the
assembly through an oven to cure the vinyl layer in place. Once the
vinyl layer has been cured, the carpet/vinyl is separated from the
belt and again wound into a roll for transfer to a third processing
line where a backing layer is adhered to the vinyl layer.
[0003] This typical manufacturing process is highly inefficient in
that it requires a separate process line for the vinyl casting
process. In addition, the method used to apply the vinyl layer
requires the use of a relatively thick layer of vinyl. The cost of
virgin vinyl is such that a reduction in the thickness of this
layer would result in a significant overall cost reduction for the
final product.
[0004] It is therefore highly desirable to incorporate a vinyl
casting process that would reduce the amount of virgin vinyl
required to manufacture the carpet product and that would eliminate
the need for a separate vinyl casting processing line.
SUMMARY OF THE INVENTION
[0005] Accordingly, it is an objective of the present invention to
provide a method of assembling a vinyl-backed floor covering
wherein the finishing sub-processes are joined in a single
continuous production line.
[0006] It is another objective of the present invention to provide
a method of finishing a vinyl-backed carpet product with a reduced
virgin vinyl material content.
[0007] It is yet another objective of the present invention to
provide an improved method of applying a reinforced layer of vinyl
plastisol or other polymeric material to a textile sheet.
[0008] Toward these ends, a method of assembling a floor covering
according to the present invention comprises providing a carpet
layer having textile fibers defining an upper surface and having an
opposing carpet layer back surface. The method further comprises
forming a vinyl layer on the carpet layer back surface and adhering
a backing layer to the vinyl layer, the backing layer having a
front backing surface for adhering to the vinyl layer and an
opposing rear backing surface. According to this method, the carpet
layer is provided as a continuous sheet and the steps of forming a
vinyl layer and adhering a backing layer are performed on the
carpet layer in a continuous manner in a single carpet finishing
line.
[0009] A method of assembling a floor covering according to the
present invention may further comprise the step of applying an
adhesive to the rear backing surface, wherein this step is
performed in a continuous manner in the single carpet finishing
line. The adhesive is preferably an oleophobic pressure sensitive
adhesive. Where an adhesive is applied, it is preferred that the
method further include the step of applying a release cover over
the adhesive to prevent inadvertent adhesion of the adhesive prior
to installation of the floor covering.
[0010] A method of assembling a floor covering according to the
present invention may comprise the step of applying a barrier layer
to the rear backing surface, the barrier layer having an upper
barrier surface adjacent the rear backing surface and a lower
barrier surface. The barrier layer is effective for substantially
inhibiting migration of moisture from a substrate into the backing
layer and for substantially inhibiting migration of backing
constituents from the backing to the substrate. The method may
further comprise applying an adhesive to the rear barrier surface.
The barrier surface in this variation would be effective for
substantially inhibiting migration of backing constituents from the
backing to the adhesive.
[0011] The carpet layer in a method of assembling a floor covering
according to the present invention may include a resin composition
layer having a front resin surface adhered to at least a portion of
the textile fibers and an opposing back resin surface. The carpet
layer may include a primary backing to which the textile fibers are
attached, the resin composition layer being formed so as to lock
the textile fibers to the primary backing. Alternatively, the
textile fibers of the carpet layer may be configured as interwoven
warp and weft yarns which form a woven carpet fabric having a
traffic surface and an opposing rear fabric surface. The warp and
weft yarns of the woven carpet fabric define interstices
therebetween. The resin composition layer is preferably formed on
the rear fabric surface so that a portion of the resin composition
layer occupies at least a portion of the interstices.
[0012] In a preferred method of assembling a floor covering
according to the present invention, the step of forming a vinyl
layer includes continuously moving the carpet layer through a vinyl
application station. This method further includes depositing a
first portion of uncured vinyl material on the carpet layer back
surface and spreading the first portion of uncured vinyl material
across the carpet layer back surface. The method also includes the
step of establishing a substantially uniform predetermined
thickness of the vinyl layer. The step of establishing a
substantially uniform predetermined thickness preferably includes
passing the carpet layer through means for removing excess vinyl
material and controlling the thickness of the vinyl layer. The step
of establishing a substantially uniform predetermined thickness may
include passing the carpet layer between a thickness control roller
and a base surface in a predetermined direction. The thickness
control roller is configured for engaging and spreading the vinyl
material across the carpet layer back surface to provide a
substantially uniform vinyl layer. The control roller layer has an
outer surface, a portion of which is in contact with the vinyl
material and preferably is rotated at a predetermined rate in a
direction such that the portion of the control roller surface in
contact with the vinyl material moves in a direction opposite to
the predetermined direction of motion of the carpet layer.
[0013] The step of forming a vinyl layer in a method of assembling
a floor covering according to the present invention may include
applying a scrim sheet over the first portion of uncured vinyl
material spread on the carpet layer back surface and depositing a
second portion of uncured vinyl material over the scrim sheet.
[0014] The step of forming a vinyl layer in a method of assembling
a floor covering according to the present invention preferably
further includes heating the uncured vinyl material to a
temperature above the cure temperature of the vinyl material to
cure the vinyl layer and permanently adhere the vinyl layer to the
carpet layer back surface.
[0015] The vinyl layer formed in the methods according to the
present invention is preferably formed from a polyvinyl chloride
plastisol material.
[0016] An illustrative method of assembling a floor covering
according to the present invention comprises providing a carpet
layer having textile fibers defining an upper surface and having an
opposing carpet layer back surface. This illustrative method
further comprises depositing a first portion of uncured vinyl
material on the carpet layer back surface and spreading the first
portion of uncured vinyl material across the carpet layer back
surface. The method still further comprises applying a scrim sheet
over the first portion of uncured vinyl material and depositing a
second portion of uncured vinyl material over the scrim sheet.. The
carpet layer is then passed between a thickness control roller and
a base surface in a predetermined direction. The control roller has
an outer surface, a portion of which engages the second portion of
uncured vinyl material. The control roller is rotated at a
predetermined rate in a direction such that the portion of the
control roller surface engaging the vinyl material moves in a
direction opposite to the predetermined direction of motion of the
carpet layer, thereby establishing a vinyl and scrim laminate
having a substantially uniform thickness. The illustrative method
also comprises heating the uncured vinyl material to a temperature
above the cure temperature of the vinyl material to cure the vinyl
and permanently adhere the vinyl and scrim laminate to the carpet
layer back surface. A backing layer is adhered to the vinyl layer,
the backing layer having a front backing surface for adhering to
the vinyl layer and an opposing rear backing surface. The carpet
layer is preferably provided as a continuous sheet and the steps of
depositing a first portion of uncured vinyl material, spreading the
first portion of uncured vinyl, applying a scrim sheet, depositing
a second portion of uncured vinyl material, passing the carpet
layer between a thickness control roller and a base surface,
heating the uncured vinyl material; and adhering a backing layer
are preferably performed on the carpet layer in a continuous manner
in a single carpet finishing line.
[0017] A method of applying a polymeric material to a textile sheet
having opposed first and second surfaces according to the present
invention comprises the steps of forming a plastisol from the
polymeric material, depositing a first portion of plastisol on the
first surface of the textile sheet and spreading the first portion
of plastisol across the first surface of the textile sheet. The
textile sheet is passed between a thickness control roller and a
base surface in a predetermined direction. The control roller has
an outer surface, a portion of which engages the plastisol. The
control roller is rotated at a predetermined rate in a direction
such that the portion of the control roller surface engaging the
plastisol moves in a direction opposite to the predetermined
direction of motion of the textile sheet, thereby establishing a
layer of polymeric material having a substantially uniform
thickness. The method preferably further comprises the step of
heating the plastisol to a temperature above the cure temperature
of the polymeric material to cure the polymeric material and
permanently adhere the polymeric material to the textile sheet.
[0018] A method of forming a laminate having a textile sheet with
opposing first and second surfaces, a first polymeric composition
layer adhered thereto, a reinforcement sheet and a second polymeric
composition layer according to the present invention comprises the
steps of forming a plastisol including at least one polymeric resin
material and depositing a first portion of plastisol on the first
surface of the textile sheet. The method further comprises applying
a reinforcement sheet over the first portion of plastisol and
depositing a second portion of plastisol over the reinforcement
sheet. The textile sheet is passed between a thickness control
roller and a base surface in a predetermined direction. The control
roller has an outer surface, a portion of which engages the second
portion of plastisol. The control roller is rotated at a
predetermined rate in a direction such that the portion of the
control roller surface engaging the plastisol moves in a direction
opposite to the predetermined direction of motion of the textile
sheet, thereby establishing a substantially uniform overall
thickness of the laminate. The method preferably further comprises
the step of heating the plastisol to a temperature above the cure
temperature of the polymeric material to cure the polymeric
material and permanently adhere the polymeric material to the
textile sheet. The reinforcement sheet in a laminate formed by this
method may be a fiberglass scrim material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-sectional illustration of a carpet product
that may be assembled using the method of the present
invention;
[0020] FIG. 2 is a schematic illustration of a process according to
the present invention; and
[0021] FIG. 3 is a schematic illustration of a vinyl layer
application station that may be used in the process illustrated in
FIG. 2.
DETAILED DESCRIPTION
[0022] The present invention is directed to a method for producing
a finished vinyl-backed carpet. This method uses a single,
continuous process line for forming a vinyl layer on and adhering a
backing layer to a pre-coated, unbacked carpet material. FIG. 1
illustrates a typical tufted carpet product 40 as produced by this
method. The carpet product 40 has a series of fiber tufts 41
attached to a woven primary backing 43. An optional pre-coat layer
44 serves to lock the fiber tufts 41 to the primary backing 43. A
pair of vinyl layers 46, 48 surrounding a scrim material 21 is
formed on the back of the pre-coat layer 44. The vinyl layer or
layers is typically formed from a polyvinyl chloride (PVC)
plastisol material. In an alternative embodiment, the scrim 21 is
not used, in which case the second vinyl layer 48 is applied
directly to the first vinyl layer 46, essentially forming a single
vinyl layer. A secondary backing 27 is adhered to the back of the
second vinyl layer 48. An optional adhesive layer 31 with a
releasable cover sheet 37 may be adhered to the bottom of the
backing layer.
[0023] The method of the present invention may be used with either
tufted or woven carpet materials. A woven carpet product assembled
using a method according to the present invention would have a
series of warp and weft yarns forming a woven carpet fabric. A
pre-coat layer preferably occupies at least a portion of the
interstices formed by the warp and weft yarns. Below the pre-coat
layer, the layup for the woven carpet is essentially the same as
for the tufted carpet.
[0024] The scrim 21 reinforces the vinyl layers 46, 48 and provides
dimensional stability to the finished carpet product. The scrim 21
is typically a fiberglass sheet material but may be formed from
other materials as well. The benefits of the scrim 21 are obtained
by encapsulating the scrim 21 within the vinyl layers 46, 48 of the
carpet. The overall thickness of the combined vinyl layers 46, 48
need be no greater than that which is required to encapsulate the
scrim 21 and to provide a substantially smooth, even surface for
adhering the backing layer 27.
[0025] The method of the present invention incorporates a vinyl
layer application process that involves applying a predetermined
amount of vinyl material directly to the back of the pre-coated
carpet starting material. This application process allows the
formation of a uniform vinyl layer that is thinner than layers
obtainable through the use of present processes. This allows the
production of a finished carpet that has a lower virgin vinyl
material content than previous products. In addition, the new
process eliminates the need for a separate curing process for the
vinyl layer, which in turn facilitates the integration of two
formerly separate process lines.
[0026] While the following description will discuss the invention
as it relates to unfinished carpet, one skilled in the art will
understand that the vinyl application process described is
applicable to other sheet materials on which a thin, controllable
vinyl layer is desired. The application process may also be used to
apply other materials other than PVC to carpets or other sheet
materials.
[0027] With reference now to FIG. 2, there is shown a schematic
diagram of a processing line 10 used to perform a process in
accordance with the present invention. Unfinished carpet material
11 is taken from a roll 12 and passed through a vinyl application
station 14 where vinyl and, if desired, a sheet of scrim material
21 are applied to form a carpet/vinyl laminate 11a. The
carpet/vinyl laminate 11a is passed through an oven 26 to cure the
vinyl layer in place. A radiant heater 29 is then used to heat the
vinyl layer so that a backing material 27 can be adhered thereto
using the rollers 30. An adhesive may be added to the backed carpet
11b using adhesive applicator 32. The adhesive is then dried in a
dryer 35 to form an adhesive backed carpet 11c. A releasable
plastic cover sheet 37 is applied. After passing around a cooling
drum 38, the finished carpet product 11d is gathered into a
finished carpet roll 40.
[0028] The process of the present invention will now be discussed
in more detail. As illustrated in FIG. 2, the unfinished carpet
starting material 11 is typically provided in the form of a roll
12. In order to maintain a continuous process, the free end of
material 11 of a new roll 12 is attached to the trailing end of the
material 11 from a previous roll 12. After attachment, the material
11 is gathered in a J-box or other material accumulator (not shown)
to assure that the process may continue uninterrupted when the new
roll of material 11 is attached.
[0029] Although the unfinished carpet starting material 11 may be
used in an uncoated state, it is typically provided with a resin
composition pre-coat layer adhered to the back of the material. As
noted above, in a tufted carpet material, the pre-coat layer serves
to lock the tufts to a woven primary backing. In a woven carpet
material, the resin composition pre-coat layer may be formulated to
penetrate the interstices of the woven material and encapsulate
portions of the woven fibers as described in U.S. patent
application Ser. No. 09/368,983 (the "'983 application"), which is
incorporated by reference herein in its entirety. The pre-coat
material may be ethylene vinyl acetate, PVC, styrene acrylic or
other resin compositions such as those disclosed in the '983
Application.
[0030] In a preferred embodiment, the pre-coat layer is applied to
the unfinished carpet material in a separate process line. It will
be understood by those having ordinary skill in the art, that the
application of the pre-coat could also be made a part of the
process line of FIG. 2.
[0031] The carpet material 11 is continuously removed from the
accumulator and fed to the vinyl application station 14.
Heretofore, it has been necessary to apply at least the majority of
the vinyl layers in an indirect manner. Specifically, in the old
process, uncured virgin vinyl material is deposited on a continuous
casting belt and formed into a substantially uniform layer by
passing the belt beneath a straight-edged doctor blade. The doctor
blade spreads the material and establishes the initial layer
thickness. A sheet of scrim is then laid on top of the first vinyl
layer. More vinyl is then deposited on top of the scrim and the
material again passed beneath a doctor blade to spread the material
into a second uniform layer. Importantly, the thicknesses of the
two vinyl layers must be great enough that the scrim material is
not torn or deformed when the material is passed under the doctor
blade. After application of the second vinyl layer, the unfinished
carpet material is laid on top of the vinyl/scrim layers and the
combined materials are passed through a pair of rollers to press
them together to form a single laminate. If desired, the pre-coated
back of the unfinished carpet material may be coated with a third
layer of vinyl prior to laying it on top of the vinyl/scrim layers.
The vinyl-backed carpet is then passed through a curing oven to
cure the vinyl in place. As the carpet exits the curing oven, it is
cooled and separated from the belt. The vinyl layer releases from
the belt and remains adhered to the back of the carpet. The carpet
is then wound into a roll and transported to a finishing line where
the vinyl is reheated for application of a backing layer.
[0032] The old method has several distinct disadvantages. First, it
requires the use of a casting belt that must be coated with
Teflon.RTM. or similar material to allow the release of the vinyl
from the belt after it has been cast and cured. Second, the old
method of vinyl application required that the thicknesses of the
vinyl layer be greater than would otherwise be required. Smaller
thicknesses cannot be produced because of the likelihood of damage
to the scrim. In addition, when controlled by the use of a doctor
blade, thickness uniformity decreases as thinner layers are
produced.
[0033] The method according to the present invention eliminates the
need for application of the vinyl to a belt and does not use a
doctor blade for layer thickness control. In the present method,
the vinyl layer is applied directly to the back of the carpet.
[0034] Referring now to FIG. 3, the vinyl layer applicator station
14 is configured to apply a layer of vinyl on the back of the
carpet with an encapsulated scrim sheet if desired. The direction
of motion of the carpet layer 11 is illustrated by arrows 13. The
vinyl is applied in two stages. A first vinyl portion is applied
using a pan applicator 19 having an application roller 16. The
application roller 16 is positioned so that as the roller 16
rotates, it collects the PVC plastisol material 17 from a pan 18.
The carpet is fed into the pan applicator 19 so that the
application roller 16 contacts the back of the carpet and deposits
the vinyl material thereon. The amount of vinyl deposited is
determined by the viscosity of the vinyl material, the speed of
passage of the carpet material 11 and the rotation speed of the
application roller 16. The carpet is then passed over a press bar
20 that removes excess vinyl material and establishes a
substantially uniform thickness. This initial application of vinyl
may also be accomplished using other forms of applicators known in
the art.
[0035] The carpet material 11 is then passed between a thickness
control roller 50 and a conveying roller 52. The conveying roller
52 is in contact with the traffic face side of the carpet material
11 and rotates in the direction of motion of the carpet material 11
through the applicator 14. The thickness control roller 50 is used
to remove excess vinyl material and precisely control the thickness
of the vinyl layer. The thickness control roller 50 is precisely
counter-balanced to "float" over the vinyl material to establish
the desired layer thickness. It has been found that a high degree
of control and consequent thickness uniformity can be achieved by
rotating the control roller 50 at a predetermined rate in the
direction 51 opposite to the direction 13 of movement of the carpet
material 11. This was a surprising result and contrary to prior
practice in similar uses of such rollers. The desirable rate of
rotation of the control roller 50 may vary with the vinyl
viscosity, the desired layer thickness and the speed at which the
carpet layer is moved past the control roller 50.
[0036] It will be understood by those having ordinary skill in the
art that the conveying roller 52 provides a base surface to assure
that the control roller 50 provides a uniform desired thickness.
Other methods of providing a smooth, flat base surface may be used
without departing from the scope of the present invention.
[0037] If desired, additional vinyl may be applied at a secondary
application station 24 just upstream of the control roller 50. The
secondary application station 24 can include an additional pan
applicator or standard direct applicator heads. The additional
vinyl applicator 24 is particularly significant when it is desired
to encapsulate a sheet of scrim 21 within the vinyl layer. As shown
in FIG. 3, a sheet of scrim 21 is taken off a roll 22 and is
contacted to the back of the carpet material 11 on which the first
portion of vinyl has been deposited. The secondary applicator 24
then deposits a second portion of vinyl over the scrim 21. The
carpet material is then passed between the thickness control roller
50 and the conveying roller 52.
[0038] As previously noted, the thickness of the final vinyl layer
need be no greater than that which is required to encapsulate the
scrim and to provide a substantially smooth, even surface for
adhering a backing layer. The location of the scrim 21 within the
overall vinyl layer is not significant as long as there is
sufficient vinyl material to facilitate bonding of the backing
layer to the carpet. Thus, the thickness of the vinyl layers 46, 48
on either side of the scrim 21 need not be precisely controlled.
The use of the thickness control roller 50 allows the overall
thickness of the combined vinyl and scrim laminate to be uniformly
maintained while maintaining complete encapsulation of the scrim 21
and without damaging or distorting the scrim 21.
[0039] A typical overall weight of vinyl used in the
above-described method is about 37 ounces per square yard of
carpet. To achieve this overall weight, the first vinyl layer can
be formed from about 5 to 20 ounces of vinyl per square yard of
carpet material. The second vinyl layer would therefore vary from
about 17 to 32 ounces per square yard. For comparison, the process
constraints of the belt casting method force typically require the
use of at least 45 ounces of vinyl per square yard. Accordingly, a
typical carpet formed using the present method has 15-20% less
virgin vinyl than typical carpets formed using previous
methods.
[0040] Once the vinyl layers have been applied to the back of the
carpet, the carpet is routed through a curing device 26 for curing
the vinyl layer. The curing device 26 may be a heater, oven, or
other curing means known to those skilled in the art. The curing
device is preferably an oven set at a temperature sufficient to
cure the vinyl layer for further processing of the carpet. The
temperature required is a function of the vinyl layer thickness,
the length of the oven and the rate at which the carpet is passed
through the oven. Any combination that assures that the entire
vinyl layer exceeds its cure temperature may be used. In one
illustrative embodiment, the vinyl-backed carpet material 11a is
placed on a belt and passed through an oven at a temperature of
400.degree. F. in order to cure the vinyl material, which is a
plastisol having a cure temperature in the range of about 340
360.degree. F.
[0041] It will be understood that because the method of the present
invention results in a thinner vinyl layer, there is a significant
reduction in the energy required for curing the vinyl material.
This provides added environmental and cost saving benefits.
[0042] When the carpet material 11a exits the curing device 26, a
backing 27 is applied to the vinyl layer. This is preferably
accomplished by heating the surface of the vinyl layer using a
radiant infrared heater 29 and contacting the backing 27 to the
vinyl layer. The surface of the backing 27 may also be heated prior
to adhering the backing 27 to the vinyl layer. The carpet material
11a and the backing 27 are then pressed together by a pair of
rollers 30 to form a backed carpet material 11b. The rollers 30
apply sufficient pressure to assure secure adhesion of the backing
layer 27 to the preheated vinyl layer.
[0043] The backing 27 may be a padded (i.e., foamed) or a
non-padded vinyl-based material of any construction suitable for
use with rolled or tiled carpet products. One preferred backing
layer is formed from recycled waste polymeric material as described
in U.S. Pat. Nos. 5,728,741; 5,855,981; and 5, 914,343, each of
which is incorporated by reference herein in its entirety. The
backing 27 is typically manufactured in a separate line and
supplied to the present carpet finishing line in the form of a roll
28.
[0044] Additional layers may then be applied to the backed carpet
material 11b. If desired, an adhesive may be applied to the carpet
backing layer using an adhesive applicator 32. The adhesive
applicator 32 typically has a roller 34 that applies the adhesive
to the carpet back. The adhesive may be a pressure sensitive or
other adhesive suitable for carpet applications. The adhesive is
preferably an oleophobic adhesive. As used herein the term
"oleophobic" means the adhesive is resistant to the adverse effects
of plasticizer migration. Suitable pressure sensitive oleophobic
adhesives are described in U.S. Pat. No. 4,849,267, which is
incorporated herein by reference in its entirety.
[0045] As an alternative to using a plasticizer-resistant adhesive,
it may be desirable to apply a plasticizer-resistant barrier layer
to the backed carpet 11b prior to the application of the adhesive
layer. Such a barrier layer is desirable because it prevents
migration of plasticizer out of the backing layer and also prevents
moisture from penetrating into the backing layer from a substrate.
Suitable barrier layer materials are described in detail in U.S.
patent application Ser. No. 09/637,408.
[0046] Once the adhesive layer has been applied to the backed
carpet 11b, the carpet 11b is passed through a dryer 35. In one
embodiment, the dryer is an oven set at a temperature sufficient to
drive water from the adhesive layer. Typically, the temperature of
the oven is above about 200.degree. F. Other embodiments may use
infrared heaters or convection fans.
[0047] When the adhesive-backed carpet 11c exits the dryer 35, a
releasable plastic sheet 36 is preferably applied over the adhesive
layer. The finished carpet 11d is then passed over a cooling drum
38 and taken up into a roll 40.
[0048] The resulting carpet product 11d has a thin, uniform vinyl
layer with a lower virgin vinyl material content than carpet
products produced using prior methods. In addition, in the
finishing method of the present invention, the entire finishing
process is accomplished in a single manufacturing line.
[0049] It will be readily understood by those persons skilled in
the art that the present invention is susceptible to broad utility
and application. Many embodiments and adaptations of the present
invention other than those herein described, as well as many
variations, modifications and equivalent arrangement, will be
apparent from or reasonably suggested by the present invention and
the foregoing description without departing from the substance or
scope of the present invention.
[0050] Accordingly, while the present invention has been described
in detail in relation to its preferred embodiment, it is to be
understood that this disclosure is only illustrative and exemplary
of the present invention and is made merely for purposes of
providing a full and enabling disclosure of the invention. The
foregoing disclosure is not intended to be construed to limit the
present invention or otherwise exclude any other embodiments,
adaptations, variations, modifications or equivalent arrangements,
the present invention being limited only by the claims and the
equivalents thereof.
[0051] Attorney Docket No.: 58568.000003
EXPRESS MAIL CERTIFICATION UNDER 37 C.F.R. 1.10
[0052] I hereby certify that the following enclosures are being
deposited with the U.S. Postal Service Express Mail (Express Mail
Label No. EJ154887326) on Nov. 28, 2000 for delivery to the
Assistant Commissioner for Patents, Box Patent Application,
Washington, D.C. 20231: A patent application of Wallace J. Hammel
et al. entitled A METHOD FOR ASSEMBLING A REINFORCED VINYL-BACKED
CARPET including 17 pages of specification, 8 pages of claims
(claims 1-28), 1 page of abstract and 3 sheets of drawings (FIGS.
1-3); a Utility Patent Application Transmittal form; a Fee
Transmittal form; an unexecuted Declaration/Power of Attorney
document; check no. 185352 in the amount of $934.00 to cover filing
fees; and a self-addressed, stamped return postcard.
[0053] Sharon Puckett
* * * * *