U.S. patent number RE31,826 [Application Number 06/503,206] was granted by the patent office on 1985-02-05 for hot melt adhesive bonded pile fabrics.
This patent grant is currently assigned to Milliken Research Corporation. Invention is credited to Greville Machell.
United States Patent |
RE31,826 |
Machell |
February 5, 1985 |
**Please see images for:
( Certificate of Correction ) ** |
Hot melt adhesive bonded pile fabrics
Abstract
A hot melt adhesive bonded pile fabric is provided which
comprises a liquid permeable base layer; a pile forming yarn
adjacent to the base layer in pile forming fashion but not tufted
through the base layer; the pile forming element having been bonded
to the base layer by means of a hot melt adhesive applied to the
back of said base layer. A method and apparatus for making fusion
bonded, pile fabrics are also provided.
Inventors: |
Machell; Greville (Spartanburg,
SC) |
Assignee: |
Milliken Research Corporation
(Spartanburg, SC)
|
Family
ID: |
26974049 |
Appl.
No.: |
06/503,206 |
Filed: |
June 10, 1983 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
304486 |
Sep 22, 1981 |
04371576 |
Feb 1, 1983 |
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Current U.S.
Class: |
428/94; 428/92;
428/93; 428/95; 428/96; 428/97 |
Current CPC
Class: |
D04H
11/04 (20130101); Y10T 428/23964 (20150401); Y10T
428/23971 (20150401); Y10T 428/23986 (20150401); Y10T
428/23957 (20150401); Y10T 428/23979 (20150401); Y10T
428/23993 (20150401) |
Current International
Class: |
D04H
11/00 (20060101); D04H 11/04 (20060101); D04H
011/08 () |
Field of
Search: |
;428/85,92,93,94,95,96,97 ;156/72 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McCamish; Marion
Attorney, Agent or Firm: Petry; H. William Moyer; Terry
T.
Claims
What is claimed is:
1. A hot melt adhesive bonded pile fabric which comprises a
liquid-permeable base layer, a pile forming yarn adjacent to but
not tufted through the base layer in pile forming fashion, the pile
forming yarn having been bonded to the base layer by means of a hot
melt adhesive applied to the back of said base layer and forced
through the base layer into contact with said pile forming
yarn.
2. The pile fabric of claim 1 wherein said pile forming yarn is
provided adjacent to said base layer in folded fashion.
3. A carpet tile comprising a liquid-permeable base layer, a pile
forming yarn adjacent to, but not tufted through the base layer in
folded, pile forming fashion, the pile forming yarn having been
bonded to the base layer by means of a hot melt adhesive applied to
the back of said base layer and forced through the base layer into
contact with said pile forming yarn; said carpet tile including a
backing layer of thermoplastic material having been bonded to said
base layer by means of said hot melt adhesive.
4. The carpet tile of claim 3 wherein said backing layer includes
at least one stiffening and stabilizing membrane.
5. The carpet tile of claim 4 wherein the stiffening and
stabilizing membrane comprises glass fibers.
Description
The present invention relates to pile fabrics. More particularly
the present invention relates to a method of manufacturing hot melt
adhesive bonded pile fabrics, apparatus which may be used for
carrying out the method and the hot melt adhesive bonded pile
fabric itself.
Pile fabrics such as carpeting may be manufactured in several ways
such as by weaving, tufting, needling or bonding. In each method
the pile must be secured to a base or support layer in one way or
another. The present invention is particularly concerned in one
aspect with a method of manufacture wherein the pile is bonded by
means of a hot melt adhesive to a base layer. Such fabrics will
herein be referred to variously as hot melt adhesive bonded pile
fabrics, or hot melt adhesive bonded carpets.
A number of techniques are known for the manufacture of bonded pile
fabrics which involve the coating of a preformed base layer with a
layer of an adhesive and thereafter pressing pile-forming lengths
of a yarn into the adhesive to adhere pile-forming lengths to the
base layer.
The prior commercial techniques for making bonded fabrics have
relied very extensively on the use of PVC plastisol formulations
because of the processing disadvantages thought to be associated
with the use of other adhesive formulations such as holt melt
systems. According to such techniques a polyvinyl chloride
plastisol was applied to the base layer prior to positioning the
pile-forming yarn relative to the base layer. Then the pile yarn
may be positioned into contact with the base layer and the
plastisol may then be fused or cured, typically by heating. When
attempts were made to substitute other adhesives, such as hot melt
adhesives for the PVC plastisol in this process difficulties were
encountered. Thus, for instance, with regard to hot melt adhesives,
it has generally been thought that the apparatus employed for
positioning the yarn may become coated with the adhesive requiring
frequent shut downs of the apparatus for cleaning which is, of
course, commercially unattractive.
Thus, while PVC plastisol has been the bonding agent of choice in
the preparation of pile fabrics it is quite expensive, and it may
tend to give off noxious gases when the product is subjected to
combustion conditions. Also, while polyvinyl chloride (PVC)
plastisol compositions generally may provide good "tuft lock"
characteristics, that is its use results in a firm bond of the pile
forming yarn to the base layer, PVC plastisols generally may not
penetrate to the desired extent into the yarn bundles to effect
complete adhesion of all pile yarn fibers of the pile yarn bundle
to the pile fabric structure which may result in "fuzzing" of the
end product, especially in carpeting end uses.
Another disadvantage typically associated with the prior art
techniques for making non-tufted pile fabrics, that is fabrics
where the pile yarn is not tufted through the backing but simply
adhered to the backing, is that the adhesive is normally applied to
the base layer on the side of the base layer facing the pile yarns,
and the base layer is normally of a construction such that the
adhesive will not flow through it but will substantially remain on
that surface with perhaps some penetration into the base layer.
Then, if it is desired to apply a backing layer, e.g., a hard back,
to the back side of the pile fabric as may be desired in the making
of carpet tiles the backing layer must be either adhered directly
to the backing layer or an additional process step of applying
adhesive to the back side of the support layer may be necessary. In
either event, there is created numerous distinct layers in the
finished product, namely pile layer, adhesive layer, base layer,
another adhesive layer and a hard back layer. Such constructions
may inherently have processing disadvantages and be costly to
construct. These layers may also be subject to undesired separation
during use.
According to the present invention bonded pile fabrics are provided
wherein the bonding of the pile-forming yarn to the base layer may
be accomplished by means of a hot melt adhesive which is a
relatively inexpensive and hence commercially attractive adhesive
system, which may advantageously flow into the individual yarn
bundles to effect more complete adhesion of all the fibers of the
pile forming yarn to the pile fabric product .[.and which typically
does not give off noxious gases when the product is subjected to
combustion conditions.].. Furthermore, a process and apparatus are
provided wherein the hot melt adhesive is applied to the base layer
conveniently and in a manner which does not interfere with the
machinery employed for positioning the pile yarn. This step in the
method may accomplish an additional function, namely that of
bonding the individual pile-forming yarns to themselves typically
at or near the portion of the yarns nearest the base layer, thereby
providing improved performance characteristics to the pile fabric
product. In addition according to the invention, the adhesive may
be applied to the base layer, which is a liquid-permeable layer,
from the back of the base layer and it may be forced through the
base layer so that a one step adhesive layer application may both
provide a means for bonding the pile yarn to the base layer and
also provide a means by which a backing layer may be integrally
affixed to the base layer. The resulting product may be less
complicated and costly to manufacture and may have fewer separate
and distinct layers in the final product where undesired separation
may occur.
The pile fabrics of the present invention are hot melt adhesive
bonded fabrics which are comprised of a liquid-permeable base
layer, a pile forming yarn adjacent to but not tufted through the
base layer, in pile forming, preferably folded, fashion; the pile
forming yarn having been bonded to the base layer by means of a hot
melt adhesive applied to the back of said base layer and forced
through said base layer into contact with said pile forming yarn.
Pile forming configurations may include the so-called I-tuft
configurations, e.g., a non-folded configuration, U-tuft
configurations, and loop pile configurations, among others. With
regard to the phrase "folded, pile forming fashion," which refers
to a preferred embodiment, it should be understood that what is
intended is a configuration of the pile yarns where the yarns are
provided with at least one fold at the portion of the yarn
generally most nearly adjacent to the base layer, e.g., a cut pile
configuration. Another "folded" configuration which is contemplated
is a loop pile configuration where the pile yarns remain uncut in
the form of substantially continuous folded yarns in the final
product. A variety of pile configurations both nonfolded and folded
are illustrated in the attached drawing. According to the most
preferred embodiment the pile yarns are cut to form a folded, cut
pile product.
According to the method and apparatus of the present invention a
pile forming yarn is positioned in pile forming fashion adjacent to
one side of a liquid-permeable base layer. Thereafter a hot melt
adhesive, heated to at least its softening point is applied to the
base layer on the opposite side of the base layer from the side
adjacent to the pile forming yarn. According to the next step of
the method a hot melt adhesive may be forced, either simultaneously
with its application or in a separate step, through the base layer
into bond forming contact with the pile forming yarn, and the
adhesive is then allowed to cool, either passively or by active
cooling to a temperature below its softening temperature to thereby
bond the pile forming yarn to the base layer. The apparatus
includes a means for applying the adhesive and forcing it through
the base layer. It is to be understood that the apparatus is not
limited to means for applying only a hot melt adhesive but may
include other bonding compositions commonly used in the making of
bonded fabrics such as, for instance, polyvinyl chloride plastisol
formulations, etc.
According to a preferred embodiment of the present invention a
method and apparatus are provided wherein two continuous,
liquid-permeable base layers are positioned in a passage where they
lie in substantial parallel relationship to one another at a
predetermined distance from one another; at least one continuous
pile forming yarn is driven by folder blades alternatively against
the opposing surfaces of said base layers when they are at or near
the entrance to the above mentioned passage in such a way as to
position the pile forming yarn relative to the base layers and to
fold it zig-zag; thereafter applying to the back of said base
layers a hot melt adhesive; forcing said hot melt adhesive through
said base layers so that said hot melt adhesive contacts said pile
forming yarn; and cooling said hot melt adhesive to a temperature
below its softening point to thereby bond said pile forming yarn to
said base layers. This step in the method may accomplish an
additional function, namely that of bonding the individual pile
forming yarns to themselves typically at or near the portion of the
yarns nearest the base layer, thereby providing improved
performance characteristics to the pile fabric product. Thereafter,
the base layers may be separated from one another to form two
continuous, hot melt adhesive bonded products. Typically such
separation may be accomplished by means of a stationary or moving
knife blade positioned between the base layers which cuts the pile
yarns along the entire width of the joined base layers to provide
the hot melt adhesive bonded products.
The yarn used in forming the pile may be made of any type of fiber
know to be useful for fusion bonded fabrics such as carpets, for
example nylon, acrylics, polyester, wool, cotton and rayon.
The hot melt adhesive compositions which may be employed according
to the present invention include a wide range of hot melt adhesives
which have been available for many years. Typically such
compositions may have a melt viscosity of less than about 200,000
cps, preferably less than about 100,000 cps at 300.degree. F.
Examples include, for instance, blends of ethylene/vinyl ester
copolymer, petroleum wax and a thermoplastic resin as disclosed in
U.S. Pat. No. 3,551,231 (incorporated by reference). Other suitable
blends which may be used include ethylene/vinyl ester copolymer,
low molecular weight, low density polyethylene, microcrystalline
wax, aliphatic thermoplastic hydrocarbon resin, dicyclopentadiene
alkylation polymer, antioxidant and filler as disclosed in U.S.
Pat. No. 3,684,600 (incorporated by reference). Other suitable hot
melt adhesives of the ethylene/vinyl ester type which may be used
are disclosed in U.S. Pat. Nos. 3,583,936, 3,676,280, 3,684,600,
3,745,054, 3,723,371, 3,911,185, 3,914,489 and 4,012,547 (all
incorporated by reference). Other hot melt adhesive formulations
which may be employed include those of the atactic polypropylene
type. In general such compositions may contain a predominant
amount, e.g., from about 10 parts to about 100 parts or more,
preferably from about 60 parts to 100 parts, by weight atactic
polypropylene; from 0 to about 70 parts of another compatible
thermoplastic material such as hydrocarbon resins, waxes,
polyethylene, especially linear, low density polyethylene;
isotactic polypropylene, polyisobutylene and polybutene-1. Fillers
in widely varying amounts may be added to such compositions as will
be readily apparent to those skilled in the art.
Other compatible thermoplastic materials which may be employed in
the adhesive formulation include ethylene/ethyl acrylate,
polyacetals, polyesters, polystyrene, polyacrylonitrile,
polyacrylic ester, polymethacrylic ester, polyvinyl chloride,
polyvinylidene chloride, polyvinyl acetate, polyvinyl acetal,
polyvinyl ether, polytetrafluoroethylene, polyamide,
coumarone/indene resins, natural resins, hydrocarbon resin, bitumen
and others.
The amount of hot melt adhesive applied may vary widely, based upon
the particular pile yarn employed, base layer and properties
desired in the pile fabric product. In general the amount employed
may be from about 2 to about 200 ounces, preferably about 4 to
about 80 ounces per square yard. Tuft binds for carpet yarns that
may be achieved according to the invention may be from about 2 to
about 20 pounds.
Suitable liquid-permeable base layers which may be employed in the
product and process of the invention include woven fabrics, knitted
fabrics, non-woven scrims, felted materials, or even flexible,
foraminous materials.
Where it is desired to provide a hot melt adhesive bonded pile
fabrics of the present invention as floor covering products,
especially carpet tiles, it may be desirable to apply any of a wide
variety of suitable, resilient backing layers to the fabrics. Such
carpet tiles are also considered to be within the scope of the
present invention. The backing layer may be formed, for example,
from a suitable thermoplastic material such as blends containing
ethylene/vinyl acetate copolymers, atactic polypropylene, bitumen
hydrocarbon resins, waxes, synthetic and natural rubbers.
The backing may be bonded to the base layer by means of the same
adhesive applied to the base layer to bond the pile fabrics. Thus,
the resulting product may have fewer separate layers subject to
separation than known carpet tiles. This is, rather than having
pile layer, adhesive layer, base layer, another adhesive layer and
backing layer, the present carpet tile may typically have a pile
layer; a single, integral, hot melt adhesive layer into which the
base layer may be disposed or suspended, and a backing layer bonded
to the composite by means of the hot melt adhesive. The backing
layer may be provided with at least one stiffening and stabilizing
membrane, such as woven or nonwoven glass fibers. After the backing
has been applied the consolidated material may then be severed by
suitable cutting means into a carpet tile by any of a variety of
techniques which are well-known to those skilled in the art.
The resulting carpet tile product is suitable for use as a floor
covering in home and/or commercial use in an office environment
where substantial high stress conditions (e.g., wheeled traffic)
are applied across the tiles. The tiles typically have a dense pile
and may not require adhesives for installation. The individual
modules may be replaced or rotated as necessary or desired. The
carpet tiles may also have excellent dimensional stability with
substantially no curling, slipping, buckling, stretching or
shrinking. In addition the carpet tiles may have low smoke emission
and low "fuzzing" characteristics.
The invention may be further understood by reference to the
drawings and accompanying description thereof. It is to be
understood, however, that various changes may be made without
departing from the scope or spirit of the invention which is to be
limited only by the scope of the appended claims. Referring now to
the drawings:
FIG. 1 is an elevation view of the apparatus; and
FIGS. 2 through 4 illustrate various embodiments for forcing the
adhesive through the base layer.
FIGS. 5 through 8 illustrate various pile forming configurations
which may be employed in the hot melt adhesive bonded pile fabrics
of the present invention.
FIGS. 9 and 10 illustrate conventional tufted pile fabric
configurations showing the pile yarns tufted through a base layer.
FIG. 11 illustrates a conventional I-tuft bonded fabric
configuration showing a relatively impermeable base layer.
Referring now to FIG. 1, carpet yarn 10 is supplied from a yarn
source (not shown) over and around guide rolls 12 and 14 and down
to the vertical guides 16. Base layer 17 is supplied from rolls 18
into position between the guides 16. As the yarn 10 enters between
the vertical guides 16 the folding blades 20 and 22 alternately
displace the yarn in a zig-zag fashion into one or the other of the
base layer sheets 17 as the carpet backing is being drawn
downwardly. Pivotally mounted bladelets 24 and 26 may assist in the
folding of the yarn. Folding blades 20 and 22 are mounted,
respectively, to connecting rods 28 and 30. Connecting rod 28 is
pivotally connected to pivot shafts 32 and 34 and connecting rod 30
is pivotally connected to pivot shafts 36 and 38 through suitable
links (not shown). The shafts 32 and 38 are oscillated by an
oscillating crank arm mechanism (not shown).
It should be noted that the blade 20 is out of phase with the blade
22 so that when the blade 22 is being pivoted inwardly as shown in
FIG. 1 the blade 20 is being pivoted outwardly and vice versa to
provide a zig-zag configuration of the yarn between the carpet base
layers 17 which are liquid-permeable, that is permeable to the
adhesive to be applied.
After the yarn has been positioned in zig-zag configuration between
the carpet base layers 17, hot melt adhesive 80 maintained in
troughs 82 is applied to applicator rolls 84 by passing through
gaps 86 between the side walls 88 of the troughs 82 and the
applicator rolls 84. The hot melt adhesive may be maintained in the
liquid phase by heating means not shown. The amount of adhesive
applied to the applicator rolls may be adjusted as desired by
moving troughs 82 upwardly or downwardly as indicated. Applicator
rolls 84 are caused to move preferably in the directions indicated
by drive means not shown whereby adhesive is applied to the carpet
base layers 17 and simultaneously forced through the base layers
into contact with yarn 10. The rolls may also be forced to move in
the opposite direction to the direction indicated if so
desired.
After the hot melt adhesive has been applied to the carpet base
layer and forced through it into contact with the carpet yarn, it
may be converted into the solid phase by cooling means 90 to form a
bond between the carpet yarn 10 and the carpet base layers 17.
Cooling means 90 may be supplied with air blowers 92, cooling coils
94 over which air is forced and thereby cooled prior to exiting the
cooling means through exit ducts 96 into contact with the carpet
base layers to thereby cool the hot melt adhesive causing it to
revert to the solid phase. The yarn 10 may then be severed,
generally in the middle of the base layers 17 by cutting blade 98
to provide, simultaneously, two sheets of carpet.
FIG. 2 is an enlarged view of the hot melt adhesive applicator
means embodiment 78 shown in FIG. 1. Numbers in FIG. 2
corresponding to numbers used in preceding drawings refer to
corresponding parts of the apparatus. The gaps 86 by means of which
the amount of hot melt adhesive to be applied may be adjusted as
desired are more clearly illustrated. Also shown in FIG. 2 are
pre-heating plates 101 which may be provided to pre-heat the base
layers prior to application of hot melt adhesive and to facilitate
such application.
FIG. 3 illustrates an alternative embodiment wherein the hot melt
adhesive is maintained in a reservoir sided on one side by base
layers 17 and on the other side by doctor blades 104. The adhesive
80 is allowed to contact the carpet backings and is forced
therethrough by the tips 106 of doctor blades 104.
FIG. 4 illustrates yet another embodiment of the invention where
the hot melt adhesive is maintained in tanks 108. Application of
the adhesive to the base layers 17 is accomplished by drawing the
adhesive out of the tanks 80 through pumps 119 into manifolds 112.
The adhesive is then forced from the openings 114 in manifolds 112
under sufficient pressure to force the adhesive through the carpet
base layers 17 into contact with carpet yarn 10.
FIG. 5 illustrates an embodiment of the present invention showing
an I-tuft configuration of the pile yarns, base layer 17 in the
form of a relatively open-weave, adhesive permeable fabric. Hot
melt adhesive 80 is shown as a continuous layer into which the base
layer 17 has become embedded at the base thereof. A backing layer
150 made of a thermoplastic material is shown as having been bonded
to the pile fabric by means of the same hot melt adhesive 80 used
to bond the pile forming yarns. FIGS. 6, 7 and 8 illustrate some
folded configurations of the pile forming yarns which may be
preferred. Identifying numbers refer to the same structural
components as in FIG. 5. FIG. 6 shows a folded, cut pile
configuration. FIG. 7 shows a loop pile configuration. FIG. 8 shows
another folded pile configuration where the folded portion of the
yarn is on the surface giving the appearance of a loop pile,
although the loops are not joined to one another at their base.
This configuration provides in essence a loop pile product while
simultaneously offering the advantages of, for instance, yarn
savings of the so-called I-tuft configuration.
FIG. 9 illustrates a conventional cut pile tufted carpet tile
having pile yarn 10 tufted through a conventional, polypropylene
backing 152, adhesive layer 153, and backing layer 154. FIG. 11
differs from FIG. 10 only in the illustration of a loop pile tufted
configuration rather than a cut pile configuration. FIG. 11
illustrates conventional, multilayered I-tuft bonded product
showing the configuration of pile yarns 10, adhesive layer 155,
adhesive impermeable base layer 156 in the form of tightly woven
jute, another adhesive layer 157 by means of which backing layer
158 may be adhered to the base layer.
The invention may be further understood by reference to the
following examples which are not to be construed as unduly limiting
the invention.
Example 1
Using a machine similar to that shown in FIG. 1, a nylon carpet
yarn was folded between layers of a woven rayon fabric. By means of
an elecrically heated plate mounted on one side only, directly
below the vertical guide 16, the yarn loops in contact with the
fabric at this side only were lightly fused to the fabric. By
omitting the hot-melt adhesive application and the cutting by the
blade, a loop-pile fabric was produced on removal of the other
non-adhering rayon fabric.
A hot-melt adhesive composition was formulated using atactic
polypropylene, hydrocarbon resin and wax, and a molten film of this
adhesive cast on a hot-plate at about 350.degree. F. A portion of
the loop-pile fabric made as described above was contacted on the
loop-pile face with a piece of non-woven glass scrim. This assembly
was then placed with the glass in contact with the hot-melt
adhesive, rolled to force the adhesive through the glass and into
the loop-pile yarns, and cooled. Then the glass side of the
sandwich was laminated under heat and pressure to a 60 mils thick
sheet of Keldax.RTM., (a trademark of DuPont for a filled hot-melt
composition based on a copolymer of ethylene and vinyl acetate). A
blade was then used to cut the yarn sandwich between the rayon
fabric and the glass, thus producing two cut-pile carpets.
Single yarns were then pulled from the carpet bonded by the
hot-melt adhesive to the glass. The average force required was
found to be 4.6 pounds.
Example 2
Used a machine similar to that of FIG. 1 with a heater plate as
described in Example 1. There was a rayon fabric on the same side
as the heater plate, an open leno-woven glass scrim fabric on the
non-heated side, and a nylon carpet yarn folded into the gap. The
glass side of the sandwich was contacted with a heated applicator
(identified as Number 84 in FIG. 1), above which was mounted a
trough 88 containing the following formulated hot-melt adhesive at
about 300.degree. F.:
______________________________________ Elvax .RTM. 350 (DuPont
ethylene/vinyl 30 parts acetate copolymer melt index - 19) Shellmax
400 (shell micro crystalline 45 parts wax, melting point
177.degree. F.) Piccopale 100 (Hercules hydrocarbon 25 parts resin,
softening point: 212.degree. F.)
______________________________________
By varying the speed of the application roll relative to the yarn
sandwich, and the gap between the trough and the applicator roll,
various levels of adhesive were applied to the yarn loops through
the woven glass scrim. After cooling and cutting of the yarns to
make two cut-pile carpets, the tuft bind was measured on the glass
backed carpet portion. Values varied from 4 pounds tuft bind with
15 ounces/square yard of adhesive to 6 pounds with 50 ounces/square
yard of adhesive.
Example 3
A hot-melt adhesive was formulated as follows:
______________________________________ Elvax 350 30 parts UE 653-04
(U.S. Industries ethylene/ 10 parts vinyl acetate copolymer, melt
index: 375) Shellmax 500 (Shell micro crystalline 35 parts wax,
melting point 171.degree. F.) Piccopale 100 25 parts
______________________________________
Using the procedure of Example 2, this adhesive was applied to the
glass side of the yarn sandwich giving tuft bind ranging from 7 to
10 pounds with an adhesive pick-up of 32 to 48 ounces/square
yard.
Example 4
With the following hot-melt adhesive formulation:
______________________________________ Elvax 260 (DuPont
ethylene/vinyl 35 parts acetate copolymer melt index: 6) Shellmax
400 40 parts Piccopale 100 25 parts
______________________________________
and using the procedure of Example 2, obtained a tuft-bind of 5
pounds with as low as 8 ounces/square yard of adhesive. With 36
ounces of adhesive, the tuft-bind was 9 pounds.
Example 5
Used the same procedure as for Example 2, except that the heated
applicator roll/trough to apply the hot-melt adhesive was replaced
by a doctor blade applicator on the glass side as depicted in FIG.
3. The adhesive was:
______________________________________ Elvax 660 (DuPont
ethylene/vinyl acetate 20 parts copolymer melt index: 2.5) D-82
(Hercules experimental hot-melt 80 parts adhesive)
______________________________________
With an adhesive pick up in the range of 5-20 ounces/square yard
following from the relatively high viscosity of this adhesive, the
tuft-bind averaged 4 pounds.
Example 6
Used the method of Example 5, but with a lower viscosity adhesive
prepared thus:
______________________________________ Atactic polypropylene 83
parts Dowlex (Dow linear low density 17 parts polyethylene, melt
index: 20) ______________________________________
A 3 pound tuft-bind was obtained with adhesive pick ups in the
range 14-30 ounces/square yard.
* * * * *