U.S. patent application number 10/627964 was filed with the patent office on 2005-02-03 for alternate method for applying hot melt adhesives to carpet.
This patent application is currently assigned to Burlington Industries, Inc.. Invention is credited to Hutchison, Robert D., Shail, Todd M..
Application Number | 20050022919 10/627964 |
Document ID | / |
Family ID | 34103299 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050022919 |
Kind Code |
A1 |
Shail, Todd M. ; et
al. |
February 3, 2005 |
Alternate method for applying hot melt adhesives to carpet
Abstract
Described are methods of making a carpet by (a) providing a
primary backing material having a front side and a back side, (b)
tufting a yarn into the primary backing material to produce a
carpet pile on the front side of the primary backing material and
loops of the yarn on the back side of the primary backing material,
(c) applying by slot coating a layer of a first melted coating
composition onto the back side of the tufted primary backing
material, (d) applying by slot coating a layer of a second melted
coating composition onto the coating applied in step (c) thereby
fixing the loops of the yarn to the primary backing material, and
(e) applying and pressing a secondary backing onto the slot coated
tackifying resin layers and pressing it to join the first and
second tackifying resins and the primary backing and secondary
backing and yarn loops together to form a carpet.
Inventors: |
Shail, Todd M.; (Roanoke,
VA) ; Hutchison, Robert D.; (Buchanan, VA) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Assignee: |
Burlington Industries, Inc.
Greensboro
NC
|
Family ID: |
34103299 |
Appl. No.: |
10/627964 |
Filed: |
July 28, 2003 |
Current U.S.
Class: |
156/72 |
Current CPC
Class: |
B32B 37/1284 20130101;
D06N 2203/048 20130101; B32B 27/12 20130101; B32B 2471/00 20130101;
D06N 2203/061 20130101; B32B 2471/02 20130101; D06N 7/0078
20130101; D06N 2205/10 20130101; D05C 17/023 20130101; D06N
2203/047 20130101; D06N 2203/065 20130101; B32B 37/12 20130101;
B32B 2037/1215 20130101; D06N 2205/18 20130101; D06N 2203/042
20130101; Y02P 70/62 20151101; Y02P 70/649 20151101 |
Class at
Publication: |
156/072 |
International
Class: |
D05C 015/00 |
Claims
1. A method of making a carpet comprising the steps of: (a)
providing a primary backing material having a front side and a back
side, (b) tufting a yarn into the primary backing material to
produce a carpet pile on the front side of the primary backing
material and loops of the yarn on the back side of the primary
backing material, (c) slot coating a layer of a first melted
coating composition onto the back side of the tufted primary
backing material, (d) slot coating a layer of a second melted
coating composition onto the coating applied in step (c) thereby
fixing the loops of the yarn to the primary backing material, and
(e) applying and pressing a secondary backing onto the slot coated
tackifying resin layers and pressing to join the first and second
tackifying resins and the primary backing and secondary backing and
yarn loops together to form a carpet.
2. The method according to claim 1 wherein the first coating
composition comprises a tackifying resin and a hot melt adhesive
resin.
3. The method according to claim 1 wherein between about 2 to about
12 ounces per square yard of the first coating composition is
applied to the primary backing material.
4. The method according to claim 1 wherein the second coating
composition comprises up to 80% by weight of a tackifying resin and
a hot melt adhesive.
5. The method according to claim 1 wherein between about 5 to about
50 ounces per square yard of the second coating composition is
applied to the primary backing.
6. The method according to claim 1 wherein between about 24 and
about 50 ounces per square yard of the first and second coating
compositions combined are applied to the primary backing.
7. The method according to claim 1 wherein the hot melt adhesive
comprises a polyethylene, polypropylene, polyamide, polyvinyl
chloride, ethylene vinyl acetate, polyester or copolymers
thereof.
8. The method according to claim 1 wherein the second coating
composition comprises an inorganic particulate filler.
9. The method according to claim 1 wherein the carpet is
constructed entirely of recyclable polymer.
10. A method of making a carpet comprising the steps of: providing
a primary backing material having a front side and a back side,
tufting a yarn into the primary backing material to produce a
carpet pile on the front side of the primary backing material and
loops of the yarn on the back side of the primary backing material,
and thereafter slot coating a layer of a melted adhesive
composition onto the back side of the tufted primary backing
material thereby fixing the loops of the yarn to the primary
backing material.
11. A method of making a carpet comprising yarn attached to a
primary backing material and securing the yarn to the backing
comprising applying to a back side of the primary backing material
a slot coating of a melted adhesive composition thereon thereby
flexibly securing the yarn to and retaining it in the primary
backing material.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to carpets and methods of making
carpets employing an efficient procedure for applying hot melt
adhesive to a carpet backing.
[0002] Carpets are constructed with a primary backing material in
which yarns are tufted through a primary backing material having a
face surface and a back surface. An adhesive is used on the back
side of the primary backing to secure the face yarns to the primary
backing. Traditionally these adhesives may be latex or PVC-based
materials. This invention uses hot melt adhesives based upon
polymers which when heated have reduced viscosity and are flowable
but upon cooling secure the carpet yarns to the primary
backing.
[0003] Roller coating and extrusion coating are two methods that
have been used to successfully apply a hot melt adhesive to the
back of the carpet primary backing. The hot melt adhesive has many
purposes and advantages over conventional latex and PVC backed
carpets. The purposes of the adhesives used in carpet manufacturing
are to encapsulate the individual fibers or filaments in the fiber
bundle of such yarns to lock them in place to prevent foot traffic
from causing the fibers or filaments to break and pill. The
adhesive also locks the bundles of yarn in place so that they are
unable to be pulled out of the carpet, as well as adhere a
secondary backing, if desired, to the back of the carpet, prevent
moisture from being able to pass through the adhesive layer, and
allows the carpet to be easily recycled by constructing the entire
carpet product of recoverable polymers. Roller coating, though
effective, typically requires a large mass of adhesive in order to
be effective. Extruders, which are very effective, are extremely
expensive.
[0004] We have found that hot melt adhesives can be applied to the
back of a carpet primary backing and effectively meet all the
objectives stated above by using a slot coat system. A slot coat
system has proven to be more successful than roll coaters and just
as effective as extruders while being much more cost effective. In
appearance, a slot coater visually looks very similar to an
extruder. A conventional extruder melts a polymer and forces it
through a die via the use of screws. Extrusion coating using an
ethylene polymer-based adhesive is described in WO 98/38374, WO
98/38375 and WO 98/38376. A slot coater melts the polymer which is
then gravity fed to a series of pumps which pump the material
through any number of application heads such as sprayers, misters,
slot dies, and the like.
[0005] Generally the adhesive backing material is applied as a
single coating or layer which affixes the yarn to the primary
backing material. The extent or tenacity to which the yarn is
affixed is referred to as tuft lock or tuft bind strength. Carpets
with sufficient tuft bind strength exhibit good wear resistance and
have long service lives. It is also desirable that the adhesive
material should substantially penetrate the yarn or fiber bundle
exposed on the back side of the primary backing material and should
substantially consolidate individual fibers within the yarn. Good
penetration of the yarn and consolidation of fibers leads to good
abrasion resistance and improved wear characteristics.
[0006] In most applications a secondary backing material, typically
a lightweight scrim made of a woven or non-woven material is
applied to the back side of the carpet and is bonded onto the
adhesive backing material. The secondary backing material provides
enhanced dimensional stability to the carpet structure.
[0007] Hot melt adhesive materials suited to the process of the
present invention are primarily thermoplastic polyolefins such as
ethylene vinyl acetate copolymers, polyethylenes, particularly low
density polyethylene as well as polyethylene, polypropylene,
polyamide, polyvinyl chloride, ethylene vinyl acetate, polyester or
copolymers thereof. We have found, in addition to a hot melt
adhesive, that it is advantageous to employ a secondary amount or
minor amount of a tackifying resin that is blended with the hot
melt adhesive. The choice of tackifying resin will depend on
several factors including compatibility with the hot melt adhesive
both in terms of processing conditions and application conditions
and as well as relative costs. Generally the tackifying resins are
more costly than the hot melt adhesives.
BRIEF SUMMARY OF THE INVENTION
[0008] Described are methods of making a carpet by (a) providing a
primary backing material having a front side and a back side, (b)
tufting a yarn into the primary backing material to produce a
carpet pile on the front side of the primary backing material and
loops of the yarn on the back side of the primary backing material,
(c) applying by slot coating a layer of a first melted coating
composition onto the back side of the tufted primary backing
material, (d) applying by slot coating a layer of a second melted
resin/adhesive coating composition onto the coating applied in step
(c) thereby fixing the loops of the yarn to the primary backing
material, and (e) applying and pressing a secondary backing onto
the slot coated tackifying resin layers and pressing it to join the
first and second tackifying resins and the primary backing and
secondary backing and yarn loops together to form a cohesive carpet
product.
[0009] The first coating composition may include a tackifying resin
and a hot melt adhesive. Typically between about 2 to about 12
ounces per square yard of the first resin coating composition is
applied to the primary backing material. The second resin coating
composition may contain up to 80% by weight of a tackifying resin
blended together with a hot melt adhesive. Between about 5 to about
50 ounces per square yard of the second coating composition is
applied to the primary backing. Overall, between about 24 and about
50 ounces per square yard of the first and second coating
compositions combined are applied to the primary backing. The hot
melt adhesive is preferably a composition based upon a
polyethylene, polypropylene, polyamide, polyvinyl chloride,
ethylene vinyl acetate, polyester or their copolymers. The second
coating composition may include an inorganic particulate filler.
Desirably the carpet is constructed substantially entirely of
recyclable polymer.
[0010] Also described are methods of making a carpet including the
steps of providing a primary backing material having a front side
and a back side, tufting a yarn into the primary backing material
to produce a carpet pile on the front side of the primary backing
material and loops of the yarn on the back side of the primary
backing material, and thereafter applying by slot coating a layer
of a melted adhesive composition onto the back side of the tufted
primary backing material thereby fixing the loops of the yarn to
the primary backing material.
[0011] The method of this invention provides a carpet comprised of
yarn attached to a primary backing material and secured to the
backing by applying to a back side of the primary backing material
a slot coated melted adhesive composition thereby flexibly securing
the yarn to and retaining it in the primary backing material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic illustration of applying by slot
coating an adhesive composition to a primary carpet backing,
applying a secondary backing and preparing a carpet.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The invention is further described with respect to the
attached FIGURE illustrating an embodiment of the invention in
which two slot coating stations are employed. The first applies a
tackifying resin or a blend of tackifying resin and a hot melt
adhesive as a pre-coat and a second slot coat station applies a
blend of a tackifying resin and a hot melt adhesive, optionally
including a filler, such as calcium carbonate or flyash, applied as
a main coat. The two slot coaters are positioned in close proximity
to one another to apply both layers of adhesive composition while
hot and somewhat fluid. The number of slot coaters used depends
upon factors such as physical properties the carpet is required to
satisfy, and cost. For example, physical properties achieved with
one unit may be sufficient for residential carpet but not for
commercial carpet or carpet tile.
[0014] The process of the present invention is characterized by the
use of one or more slot coating devices which are distinguished
from other application devices, in particular extruders, that have
been used in this art, as noted above. An extruder uses a series of
screws and pumps to force the adhesive material through a die onto
the primary backing. In contrast, a slot coater uses only pumps to
force the adhesive through a die and then onto the primary backing.
Slot coating holds the advantage of efficiently and precisely
applying a desired amount of adhesive composition to the carpet but
at a rate of application lower than that of other coating
techniques including extrusion coating. The carpets made according
to the present invention are strong, lightweight and more flexible
as a result of employing smaller quantities of adhesive, yet meet
the necessary product specifications and requirements.
[0015] Referring again to the FIGURE, once the two adhesive layers
are slot coated onto the primary backing the secondary backing is
joined to the back coated primary and compressed together by
squeeze rolls or the like to unify the primary and secondary
backing with the adhesive layer or layers therebetween and secure
the tufted fibers to the back surface of the primary backing. After
cooling to solidify the coatings, the finished carpet is then
rolled in open width or further processed into smaller units, for
instance, carpet tiles. The secondary backing material may be a
woven fabric or a non-woven fabric, such as spun-bond, wet-laid,
melt-blown or air entangled and is preferably made from a
polyolefin to facilitate recycling.
[0016] The use of two separate slot coating stations allows for
considerable flexibility in not only the amounts of adhesive
applied but also the content of the adhesive composition in
particular when blends of adhesive components are employed.
Desirably the coating weight of all adhesive layers is in the range
of about 24 to about 50 ounces per square yard and if two layers
are applied the tackifying layer is generally in the range of two
to 12 ounces per square yard, preferably about nine ounces per
square yard and the second adhesive layer is generally applied in
an amount of five to about 50 ounces per square yard, preferably
about 15 ounces per square yard. Usually the first adhesive
composition applied consists entirely or substantially entirely of
a tackifying resin or it may be a blend of tackifying resin and a
hot melt adhesive in which case the amount of tackifying resin
exceeds that of the hot melt adhesive. Conversely, if the blend of
tackifying resin and hot melt adhesive is employed as the second
adhesive composition, the amount of tackifying resin is less than
that of the amount of hot melt adhesive.
[0017] As illustrations of coating compositions suitable for the
process of this invention, the first coating layer may consist
entirely of a tackifying resin or up to 30 parts by weight of an
adhesive may be included together with the tackifying resin in the
composition. Compositions for the second layer may range from 80 to
20 parts by weight of tackifying resin and 20 to 80 parts by weight
adhesive. When a filler is included the in the second layer the
tackifying resin component ranges from 10 to 70 parts by weight,
the adhesive component 22 to 52 parts by weight, and the filler
component 8 to 38 parts by weight, with a total of 100 parts by
weight.
[0018] Our experience has indicated that when compared with roll
coaters the use of slot coating provides a reduction of about 40%
in the amount of adhesive employed, leading to not only reduced
costs but also greater flexibility and lighter weight of the
finished product.
[0019] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *