Note: Descriptions are shown in the official language in which they were submitted.
192/Canada
S P E C I F I C A T I O N
CARPET PADS HAVING PRESSURE SENSITIVE ADHESIV~
Background of the Invention
This application relates to a carpet pad and system for
holding a carpet in place without stretching. The system is
of the general type illustrated and described in United
States Patent No. 4,557,774, issued December 10, 1985 to the
same inventor and assi~nee as this application.
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The system of the present invention involves a carpet
cushion which has a pressure sensi-tive adhesive preapplied to
one surface of the cushion or padding, as opposed to U.S.
Patent No. 4,557,77~, which disclosed pressure sensitive
adhesives preapplied to both surfaces. U.S. PatPnt No.
4,557,774 is hereby incorporated in this disclosure by
reference.
The present invention also relates to carpet pads or
cushions having a hot melt pressure sensitive adhesive
applied to an otherwise uncoated and unsealed porous padding
surface which would be unsuitable for a water based pressure
~ sensitive adhesive. On such porous surfacesl water based
- ~ adhesives tend to wick excessively into unsealed porous
surfaces.
Conventionally, carpeting has been installed on floors
in several different ways. In the conventional tackless
strip system, the so-called tackless strip is secured to the
floor around the walls of the room, the carpet is hooked onto
the upwardly protruding nails of the tackless strip at one
side of the room, and the carpet is stretched before it is
hooked to the tackless strip at the opposite side of the
room. One problem with this system is that it requires the
installation of the tackless strip, which is time-consuming
and which is difficult when concr~te floors are encountered.
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Another problem is that it requires a trained professional to
re-stretch the carpet in the event a corner or edge portion
of the carpet needs to be temporarily taken up, access to the
floor or for drying a carpet which has been wetted.
Many carpet installations involve gluing of the
carpeting to the floor, without any carpet cushion or pad
between the carpet and the floor. With such an installation,
the carpeting can be of less expensive construction, with a
primary backing but without the need for a secondary backing
(jute or polypropylene backing) which is generally required
for stretched carpeting. The glued down carpeting avoids
wrinkling without the need for stretching, but loses the
benefit of a carpet pad. Also, the carpet can be very
difficult to remove either for replacement or temporarily,
for maintenance, without destroying the floor or the
carpeting itself due to the adhesion of the glue.
In glue-down installations, the carpet is ordinarily
laid on the floor first and seamed as required. The glue is
then applied to the floor, either in liquid form or by
spraying it onto the floor. This can be accomplished by
folding back half of the carpet, applying the glue to the
floor in that area, and dropping the carpet in place to
adher~ it to the floor in that area. The opposite side of
the carpet could then be folded back, glue applied to the
floor in that area, and that portion of the carpet then
adhered to the floor.
Another installation system wherein the carpet was
adhered to the floor without padding is disclosed in U.S.
Patent No. ~,405,668 to Wald. This system used a separate,
thin scrim web with adhesive on both sides and with a release
film on one side. The scrim wab was placed on a floor with
the release film on the upper surface, adhering the web to
the floor, whereupon the carpet could then be seamed and cut
~ as required while lying on top of the release film. The
carpet was then folded back and the release film removed in
one area, that portion of khe carpet was pressed down, and
the operation was repeated in another area. This system was
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relatively expensive and still did not permit the
installation of a carpet pad beneath the carpeting. A
similar construction of adhesive webbing material is shown in
U.S. Patent No. 4,234,649 to Ward.
In yet another system for installing carpet without
stretching, a slab or pad of jute material was interposed
between the carpet backing and the floor. In this particular
system the floor was sprayed with a wet adhesive, the slab of
jute material was laid into the adhesive while the adhesive
was still wet, the top surface of the jute material was
sprayed with the wet adhesive, and the carpet was laid on the
wet adhesive on the top surface of the jute slab or pad. The
wet adhesive, as it dried, became enough of a pressure
sensitive adhesive to permit the carpet to be pulled up and
removed.
This system had the disadvantage of being an expensive
system because of the costs required to make an on-the-job
~ installation.
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As noted above, U.S. Patent No. 4,557,77~ illustrates
and discloses a carpet cushion and carpet-laying system
similar to some aspects of the present invention, the
principal difference being that in some embodiments of the
present invention the cushion has a pressure-sensitive
adhesive preapplied to only one surface.
Water based pressure sensitive adhesives when applied to
a carpet cushion are liquid, and will wick excessively into
any porous surface such as the porous surface of an untreated
felt pad or rebonded urethane pad or of a porous remay which
has often been used over a carpet cushion surface. Conse-
quently, some type of surface sealing is required for the use
of such adhesives, exanlples being a thin plastic skin adhered
to the porous surface, or a sprayed-on sealant, or a crust
formed at the surface to seal the pad, as by heating. The
need for such sealing is avoided in one aspect of the present
invention described below.
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Summary of the Invention
It is a primary object of the pr~sent invention to hold
carpet in place without stretching by a system that avoids
the problems of the prior art.
It is a closely related object to hold the carpet in
place by a system that utilizes a pad with pressure sensitive
adhesive which is preapplied to one of the surfaces of the
pad, with further adhesive applied on the job, to the floor
or the upper surface of the pad, depending on which way the
pad is used.
Another object, in a preferred embodiment, is the
provision of a carpet cushion having hot melt pressure
sensitive adhesive preapplied on one or both surfaces, with
the cushion surfaces being porous and unsuitable for water
~ased pressure sensitive adhesives in the absence of surface
sealants.
By the method of the present invention, carpeting is
efficiently and economically installed without stretching or
the need for tackless strips, but still with the benefit of a
; 20 carpet cushion or pad between the floor and the carpet.
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In use of the one-sided adhesive coated carpet cushion
of the invention, first there is positioned on the floor
surface a carpet cushion having a pressure-sensitive adhesive
on one of its upper and lower surfaces. The preapplied
adhesive may be down, against the floor, or up, for
contacting and holding the carpet in place, with a releasa
film adhered to the adhesive on the upper surface. If the
adhesive side is up, an adhesive may be first applied to the
- floor, as by troweling, spraying or rolling, before the
cushion is laid down.
The carpet cushion need not include any significant
stiffener, since the adhesion to the floor will provide
needed dimensional stability.
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When the cushion has been laid and -trimmed as required,
the carpet is positioned on top of the release f'ilm (if the
adhesive side is up) on the carpet cushion, and rough cut and
seamed as required. The carpet is then folded back to expose
a portion of the carpet cushion, usually one half, and the
release film is removed from the exposed cushion.
The carpet is then pressed down onto the exposed
pressure- sensitive adhesive on the upper surface of the
carpet cushion, and another portion of the carpet is folded
back and the release film is removed from that area of the
carpet cushion. That portion of the carpet is then pressed
down.
If the adhesive side of the cushion is down, there is no
need for a release film and the carpet can be seamed and
rough cut on the cushion's upper surface by sections, with
the carpet folded back as described above.
When all areas of the carpet are in contact with the
adhesive, final trimming of the carpet edges is performed.
The described method may include installing riqid spacer
strips on the floor along the walls of the room before laying
the carpet cushion, preferably strips of wood or plastic with
pressure-sensitive adhesive on both sides. The purpose of
the spacer strips is to provide an edge similar to that of
the tackless strips, since the carpet installer's trimming
tools have been designed to trim the carpet with the hard
strip present, cutting the carpet 1/4 inch long and tucking
the carpet edge under, against the wall or baseboard. If a
tackless strip from a previous carpet installation is
present, it may be left in place with no need for the spacer
strips.
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In the manufacture of the carpet cushion, if a
water-based pressure sensitive adhesive is used, sealing
means preferably are applied to both surfacas of the pad,
which may be a foam material, to substantially seal the
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surface before the pressure- sensitive adhesive is addedO
This keeps the adhesive at the surface of the foam or other
material and prevents wicking-in. The sealing means may
comprise a thin corona treated or flame treated plastic skin
adhered to each surface at the pad in the manufacturing
process. Alternatively, it may comprise a liquid sealant
applied to the surfaces, or simply a crust formed at both the
lower and upper surfaces of the foam cushion. A crust can be
formed by a heat process, or by a curing process wherein
increased density occurs at the surfaces. A dense crust can
eliminate the need for further sealing at the surfaces of the
foam.
The adhesive need not cover the entire surface of the
carpet cushion, but may be in spaced strips. Adhesive cost
is thereby reduced without adversely affecting the positional
stability of the carpet installation. Also, this enables the
carpet cushion to be stapled or tacked to the floor, if
needed in particular areas, in the spaces between strips of
adhesive when the adhesive is on the upper surface. The
carpet will then bridge the gap over the recess or dimple
caused by the stapling, since there is no adhesive in this
area.
The adhesive on the cushion's surfaces may be applied
over the entire area or it may be in parallel serpentine
strips to discourage wrinkling of the carp~t, which tends to
occur in straight lines.
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The system of the invention enables the use of less
expensive carpeting than usually required in stretch/tackless
strip installations. The typical stretched carpet includes
an upper surface yarn, extending through a primary backing
such as a polypropylene mesh, with a secondary backing of a
jute or polypropylene mesh for dimensional stability in the
stretching operation.
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With the present system of adhesive bonding of the
carpet to the pad and the pad to the floor, the carpet does
not need an expensive secondary backing, since it is adhered
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down in substantially all areas and is not stretched.
In the manufacture of carpet cushions according to the
invention using a hot melt pressure sensitive adhesive,
sealing means are not required on the surface or surfaces of
the porous pad prior to application of the adhesive.
Further, the padding mat~rial may comprise inexpensive scrap
materials of natural or synthetic material. This can include
felt or synthetic felt or rebonded urethane scraps, all of
which have extremely porous surfaces which would cause
excessive wicking-in of a water based pressure sensitive
adhesive.
The porous carpet pad is formed in sheet-like form, in
such thickness, density and compressibility to serve as a
carpet cushion. Onto this sheet of carpet padding is applied
a hot melt pressure s0nsitive adhesive, on at lPast one
surface. The hot melt pressure sensitive adhesive is applied
at a somewhat elevated temperature, above the flow point
temperature of the hot melt pressure sensitive adhesive.
Immediately upon coming into contact with the porous surface
of the carpet cushion sheet, the hot melt pressure sensitive
adhesive lies substantially entirely on the surface, adhering
strongly to the extremity of the porous surface in a
non-flowable state. The adhesive does not appreciably wick
into the porous carpet pad surface.
The hot melt pressure sensitive adh~sive may be applied
as described to both surfaces of the carpet pad. optionally,
a scrim webbing may be applied over the hot melt pressure
sensitive adhesive layer. The scrim adheres to the adhesive
but tends to space the adhesive slightly away from a floor or
other surface, so that the carpet pad with the adhesive does
not appreciably adhere to the floor until deliberate pressure
- is applied. The scrim webbing also adds dimensional
stability, needed with certain carpet cushion materials.
It is therefore among the objects of the invention to
improve on prior carpeting installation systems and carpet
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pads by providing a carpet cushion or pad having pressure
sensitive on at least one surface, for adhering to the floor
or the carpet to the upper surface of the cushion with
adhesive applied on t~e job for the other surface, avoiding
the need for stretching or relatively expensive carpeting
which includes a secondary backing. A related object is the
provision of a carpet cushion with preapplied hot m~lt
pressure sensitive adhesive, on a padding material which is
very porous and unsealed and which may be Eormed of
inexpensive scrap materials, greatly reducing the cost of the
carpet cushion. The hot melt pressure sensitive adhesive may
be applied to one or both sides of the cushion.
Other objects, advantages and features of the invention
will be apparent from the following description of preferred
embodiments, considered along with accompanying drawings.
Description o~ the Drawings
Figure 1 is a fragmentary sectional view showing a
carpet and pad installed with the carpet pad of the
invention.
~0 Figure 2 is a perspective view showing a carpet pad
according to the invention and comprising a part of the
installation shown in Figure 1. The pad is shown comin~ off
a roll, with a release film covering one side of the adhesive
coated pad on the inside of the roll, in accordance with one
embodiment of the invention.
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Figure 3 is a perspective view showing a floor in
preparation for carpet in~tallation according to the
-~ invention, with the pad laid on the floor and the carpet
~ being unrolled on top of the pad.
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Figure 4 is a perspective view similar to Figure 3, but
showing the carpet pulled back for peeling away the release
film from the top surface of the pad, in a portion of the
floor where the carpet, already seamed and cut, has been
pulled or rolled back. In this embodiment of the system of
the invention the cushion is installed with adhesive side up
for contacting the underside of the carpet.
Eigure 5 is a plan view showing a pad according to the
invention with its pressure-sensitive adhesive applied in
parallel strips rath~r than over the entire surface of the
pad, and showing optional stapling between th strips of
adhesive.
Figure 6 is a plan view similar to Figure 4, but showing
the adhesive applied in serpentine strips.
Figure 7 is a schematic view indicating a method for
producing the carpet pad of the invention.
Figure 8 is a view like Figure 4 but showing the cushion
15 installed with the adhesive side down. An adhesive is then
applied to the upper side of the cushion prior to engaging
the carpet back to that side of the cushion. The adhesive is
applied by troweling in Figure 8.
Figure 9 is a fragmentary sectional view showing a
20 carpet cushion in accordance with another embodiment of the
, present invention, with hot melt pressure sensitive adhesive
applied to one or both sides.
Figure 10 is a schematic view indicating a method of
manufacturing a carpet cushion having hot melt pressure
`~ 25 sensitive adhesive on one or both sides.
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t Description of Preferred Embodiments
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;~ In the drawings, Figure 1 shows a carpet 10 with a pile
11 and a single backing layer or primary backing 12 laid Oll a
pad or carpet cushion 13 comprising a pad 14 which may be of
foam material, with a skin, crust or sealant 16 on both
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surfaces of the pad and a pressure-sensitive adhesive layer
17 on one of the top and bottom surfaces of the pad 14,
applied to the skin, crust or sealant 16. In accordance with
the invention the skin, crust or sealant 16 may be eliminated
when a hot melt pressure sensitive is used, on one or both
surfaces. This is discussed further below.
In Figure 1 the adhesive layer is shown on the upper
surface o~ the pad 13. In this embodiment the adhesive 17
holds the carpet backing 12 to the carpet cushion 13. If the
adhesive surface is down, on the other hand, it holds the
carpet cushion to the surface of the floor 18 below.
Installation steps with respect to these two orientations of
the carpet cushion 13 are described further below.
Figure 2 shows a roll 19 of the carpet cushion 13 of the
invention, showing the pad 14 ~which may be urethane, rubber
or felt) and the upper sealed surface 16. The adhesive layPr
17 is shown on the upper surface as the cushion 13 will be
unrolled, although it can be on the lower surface. A release
film 21 of a sheet plastic material is shown overlying the
; 20 upper surface of the carpet cushion 13, i.e., the inner
surface of the cushion on the roll 19, being temporarily
adhered to that surface. The bottom of the cushion 13, and
thus the outer surface of the roll 19 as seen in Figure 2,
need not be covered by any release film, unless the adhesive
side is outside, in which case an outer cover is used until
the roll reaches the job site.
The release film (covering the pressure sensitive
adhesive the upper surface of the padding as shown in Figure
2) enables the cushion to be laid on a floor and adhered to
the floor while still leaving the upper surface usable as a
work surface for unrolling the carpet 10 and performing
preliminary cutting and seaminy operations as necessary. For
storage and transport of the roll 19 prior to installation,
the release film may have a tail or extension 20 (dashed
lines) which wraps around the roll and covers the exposed
adhesiveO
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Figure 3 illustrates some aspects of the installation
operation according to the system of the invention. First,
rigid spacer strips 22 may be installed around the edges of
the room near the walls 23. The spacer strips 22 may be of
wood or plastic, for example, with a pressure-sensitive
adhesive 24 either preapplied onto both the upper and lower
surfaces of the strips or applied on the job to both the
upper and lower surfaces. The purpose of the strip 22 is
merely to take the place of the conventional tackless strips,
in the sense that conventional carpeting tools for trimming
the finished carpet have been designed to be used along the
edges of the ta~kless strips. If tackless strips are in
place from a prior carpet installation, they can be left
intact, and the spacer strips 22 would then not be needed.
It should also be understood that the carpet
installation according to the invention may be performed
without the use of any spacer strips 22 or tackless strips
provided the installer uses tools adequate to properly trim
the carpet without the presence of the usual rigid stripO
If the floor surface is dusty, a floor primer can be
used to lock the dust particles ko the floor, creating a
better bonding surface.
The carpet cushion 13 is unrolled onto the floor along
the spacer strips 22, which are of about the same thickness
as the cushion, generally in the manner shown in Figure 2.
Figure 3 shows the adhesive carpet cushion 13 laid and
trimmed on the floor 18, with its lower side adhered to the
floor 18.
If the preapplied pressure sensitive adhesive side is
~ 30 up, as illustrated in Figure 3, a suitable layer of glue
- ~ (pressure- sensitive or non~pressure sensitive adhesive) 20
is applied to the floor surface, as by troweling, spraying or
rolling be~ore the cushion 13 is unrolled onto the floor.
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After the cushion has been laid and trimmed, the release
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film 21 is left in place on the upper surface as shown in
Figure 3.
The carpet 10 is then unrolled over the top of the
release film, and seaming and preliminary cutting are
performed as necessary.
With the carpet seamed (carpet seaming is indicated at
25) and rough cut it is then folded back or rolled back as
indicated in Figure 4 to expose a portion 13a of the cushion.
This enables the release film 21 to be peeled off the upper
surface of that portion of the cushion 13a as indicated in
Figure 4. Once this is accomplished, the carpet is put back
into position on the sticky upper surface of the cushion
portion 13a; and the same operation is then repeated with
another portion of the carpet 10 which may be the other half
of the room. That is, the carpet is pulled or folded or
rolled back to expose another portion of the remainder of the
carpet cushion and its release film 21 is peeled off. Then
the remaining portion of the carpeting is moved back into
position, until all areas of the carpet are in contact with
the upper surface of the carpet cushion, and final trimming
operations are conducted.
If, on the other hand, the preapplied adhesive sur~ace
is laid down against the floor, then a similar operation is
performed with respect to pulling back portions of the
~` 25 carpet, but there is no release film 21 to remove since there
is no preapplied adhesive on the upper side of the cushion.
Therefore, when a section of carpet is pulled back a
pressure-sensitive or non-pressure sensitive adhesive is
applied to the cushion by spraying or troweling. The
adhesive may be a water based pressure sensitive (e.g.
acrylic) or a hot melt pressure sensitive adhesive, or any
other suitable adhesive. Figure ~ shows such an adhesive 25
being applied to the upper surface of the cushion using a
trowel 28.
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In one aspect of the invention, the adhesives used in
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some embodiments of the carpet cushion and method of the
invention are water based, and may comprise an acrylic water
based adhesive which loses its tackiness when wetted but
regains tackiness upon dryiny. ~or example, the adhesive may
be the product Flexcryl 1625 marketed by Air Products
Company. Both the preapplied adhesive and the adhesive added
on the ~ob can comprise this type of adhesive. One advantage
of this type of adhesive is its ability to regain its
tackiness after being over soaked with water. In this sense,
the adhesive is non-permanent and allows for temporary
lifting of the carpet when desired.
Once the carpet and cushion dry, the adhesive regains
its tackiness and the carpet can be pressed into the
adhesive.
The invention enable6 a less expensive water base latex
non- pressure sensitive type adhesive or a multi-purpose
adhesive to be used on the job site, either trowelled or
rolled on the floor or upper surface of the cushion.
Figure 5 shows a carpet cushion 13b according to the
invention, with spaced strips of adhesive 17a upon the
surface, separatsd by spaces 26 on the surface which have no
adhesive. This saves on the amount of adhesive required
while still providing for adequate adhesion of the carpet
cushion 13b to the floor or the carpet backing. Also, when
the adhesive is up, it enables staples 27 or tacks to be used
to hold the carpet cushion 13b down to the floor if required
under special circumstances, without causing the carpet to
recess or "dimple" inwardly at the location of the staple.
Dimpling is avoided because there is no adhesive in the
immediate vicinity of each staple 27, so the carpet does not
adhere into the recess in the cushion caused by the staple,
but rather the carpet bridges across the recess.
Figure 6 shows a serpentine pattern for adhesive strips
17b on a carpet cushion 13b, which may be desired to prevent
a pattern of wrinkling in the installed carpet. Wrinkles
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tend to occur in straight lines, so that the serpentine
pattern shown in Figure 6 discourages the occurrence of
wrinkles.
As indicated in Figure 7, in the manufacture of the
adhesive carpet cushion 13, a very thin plastic film or skin
may be bonded to or formed on both sides of the foam sheet 14
in the manufacturing proceæs, to form the sealing surface 16
described above. The skin 16 may be bonded to the surfaces
of the pad l~ by a corona-heat bonding process, SQ that it is
fused into the surfaces o the pad during the manufacturing
process (as by a hot roller), or it may be bonded by other
suitable means such as adhesives. A skin or crust may be
formed (as an integral part of the cushion) as part of the
forming process of manufacturing a foamed cushion. It may be
formed by heat applied to a foam surface. Alternatively, a
sealant 31 may be applied in lieu of the plastic skin, or
integral crust, as by liquid application or spraying by spray
nozzles 32 on both surfaces of the pad. In either event, the
surfaces are sealed to substantially close the porosity of
the foam at the surfaces.
Next, a pressure sensitive adhesive 17, either hot melt
or water based, is applied to at least one surface, as by
sprayers 33 (or by rollers, not shown), and the adhesive does
not penetrate into the foam. The prior application of the
sealing means prevents this, in the case of a wat~r based
adhesive, but it should be understood that the sealing means
can be eliminated if a hot malt pressure sensitive adhesivs
~ is used.
-~ As mentioned above, the sealing means, if needed, may alternatively comprise a crust of substantially increased
density in the surfaces of the foam pad, formed by heat, the
manner of curing of the foam, or other suitable means.
The release film 21 may next be applied to one side of
the carpet cushion 13, temporarily bonding to the adhesive on
that side. Preferably, all of these operations are
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accomplished in a continuous process wherein the foam 14,
sealing film 16 and release film 21 are advanced off roll
stock 16a and 21a as schematically indicated in Figure 7.
The sealant and adhesive are applied at appropriate points in
the operation, and the final product emerge~ complete and is
stored in rolls 19 similar to that shown in Figure 2. If the
sealing film 16 is heated by a hot roller on application (for
good bonding), roller temperature is critical. If heated to
too high a temperature the skin will develop pinholes.
Choice of skin materials is important--some skins will better
withstand heat.
A scrim webbing 35 (dashed lines) may be applied over
the adhesive layer 17, if desired. As discussed above, the
scrim webbing adds further dimensional stability and also
spaces the adhesive 17 slightly away from the floor or carpet
backing, so that the cushion (or the carpet) may be more
easily moved around before tacking it down by pressure. The
scrim must be open enough, and of sufficiently fine
filaments, that the pad will bond to the floor (or carpet
backing) when pressure is applied. A minimum of about 1/4"
opening size, and a fine filament size, should be used so
that the scrim does not hold the adhesive too strongly away
from the floor. The scrim opening size and filament size
depend to some extent on the pad's surface coarseness, with
coarser pads not requiring as fine a filament size or as
large openings.
The cushion or padding 13 can also be made from
materials other than integrally ~ormed Eoam. ~or example,
the cushion may be made from rebonded urethane, rubber or
felted needle punched synthetic with sealed surfaces on the
top and bottom, in the event water based pressure sensitive
adhesive is used.
As discussed above, another very important aspect of the
present invention is a carpet cushion or pad of the general
type described, but specifically with a hot melt pressure
sensitive adhesive applied to one or both sides of an
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otherwise porous pad surface. Figure 9 shows schematically
such a carpet cushion 3~. The cushion 38 may be formed of a
sheet of carpet padding material 39 which is of low cost
materials and with porous surfaces, sucn as would not
generally be practicable for use with a water based pressure
sensitive adhesive unless a surface sealing means were
applied, as discussed above. In this embodiment, the porous
surfaces of the pad 39 preferably are left porous, without
any treatment for sealing them. A hot melt pressure
sensitive adhesive 41 is applied to one or both sides of the
porous pad 39. Due to the nature of the hot melt pressure
sensitive, it can be applied either by spraying or by
extruding onto the surfaces, and it will adhere to the porous
surfaces in a non-flowable state, such that it cannot wick
into the cushion 39 to any appreciable degree. Sealing means
such as liquid sealants or plastic skins or heat formed
crusts may be used prior to application of the adhesive if
desired, but they are not necessary.
The material of the sheet of carpet padding 39 may
comprise inexpensive rebonded urethane scraps, for example,
or it may comprise a natural or synthetic felt or cotton
material or rubber. The pad 39 may comprise a urethane or
other foam material to which has been applied a remay, a
fuzzy layer which is usually intended to hold an adhesive
(e.g. a spun-bonded non-woven nylon or polyester~. Even in
the presence of a relatively thick remay covering, the hot
melt pressure sensitive adhesive 41 will not appreciably wick
into the remay and can be used very efficiently in producing
the carpet cushion 38. "rhe hot melt pressure sensitive
adhesive remains in a semi-solid, nonflowable state, and it
is aggressively tacky when pressed into contact with a floor
or carpet padding or other surface.
; ~ The hot melt pressure sensitive adhesive may be of
several types, such as a non-permanent, semi-permanent or
permanent adhesive, such as manufactured by Fuller
Corporation.
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As shown in the schematic diagram of Figure 10, the hot
melt pressure sensitive aclhesive material 41 may be applied
to the carpet padding sheet or base 39 ~y extruding it
(extruders 42) onto the surface or surfaces (or it can be
applied by spraying). As discussed above in connection with
Figure 7, a scrim webbing 45 (dashed lines) may be applied to
one or both surfaces, on top of the hot melt pressure
sensitive adhesive. This can add dimensional stability,
particularly in the case of inexpensive felt-like materials
or urethane materials which are otherwise not very
dimensionally stable. It also helps in manipulation of the
carpet pad 38 during the installation procedure, in allowing
it to slide around against other surfaces without significant
sticking, due to the scrim webbing's spacing of the adhesive
away from the surface to which it will ultimately adhere.
Again, as discussed above, the filament size and opening size
of the scrim must be selected (depending on the coarseness of
the pad surface) to permit good bonding of the pad to the
floor (or carpet~.
Figure 10 also shows an arrangem nt wherein a release
film 21 is applied Erom a roll 48 to one side of the cushion,
onto the hot melt pressure sensitive adhesive on that side.
The release film 21 thus enables the cushion 38 to pass over
rollers 49 and 50, en route to a stora~e roll 51 for the
completed cushion assembly 38.
The hot melt pressure sensitive adhesive may also be
advantageously applied to the padding material 39 by
spraying. It may be sprayed onto the surfaces using hot melt
spray equipment such as manufactured by Slautterback
Corporation of Monterey, California. Such adhesive may have
a flow point o~ about 300 F, although the specific flow
point temperature is not as important as the feature that the
adhesive be essentially non-flowable and aggressively tacky
at room temperature and moderately above room temperature,
and that it be capable of cooling quickly to such state upon
contacting the porous surface. Hot melt pressure sensitive
adhesives are available in a wide range of flow point
;
~ ~ g~ .J
18
temperatures.
As an alternative to the adhesive application methods
discussed above and indicated in Figure 10, the hot melt
pressure sensitive adhesive may be applied to the pad surface
by transfer coating. By this process, the hot melt pressure
sensitive adhesive is firs-t applied to a release film (such
as th~ release film 21), then the film is applied to the pad
sheet such that the adhesive contacts the pad surface. When
removed~ the release film leaves the adhesive on the pad
surface.
It should be understood that the carpet pads of the
invention, in the various forms described above, can be used
to lay a new carpet over an existing carpet, without removal
of the existing carpet. The carpet cushion of the invention,
for example the two-sided hot melt pressure sensitive
adhesive-coated cushion such as shown in Figure 9, may be
laid on top of the sur~ace of the existing carpeting. New
carpet may then be installed on the upper surface of the
carpet cushion 38. Such an installation saves greatly on
installation time and cost, and provides further cushioning
for the carpet.
The carpet pad of the invention may also form a part of
a combination carpet/pad product wherein the pad is
permanently adhered to the underside of a carpetl for
combined installation~ The hot melt pressure sensitive
adhesive is on the bottom surface of the pad or cushion.
~ he above described preferred embodiments are intended
to illustrate the principles of the present invention, but
not to limit its scope. Other embodiments and variations to
these preferred embodiments will be apparent to those skilled
in the art and may be made without departing from scope of
the invention as defined by the following claims.
I CLAIM:
