Note: Descriptions are shown in the official language in which they were submitted.
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
A method of adhering an adhesive to a fabric piece
The present invention relates to a method of adhering an adhesive to a fabric
piece. The
present invention also relates a composite structure. The present invention
also relates to
an apparatus for adhering an adhesive to a fabric. More particularly, but not
exclusively,
the present invention relates to a method of adhering an adhesive to a fabric
piece
whereby a portion of the fabric piece is pre-treated to increase its
wettability before the
adhesive and pre-treated portion of the fabric piece are pressed together,
preferably along
with the application of heat. More particularly, but not exclusively, the
present invention
relates to a composite structure produced by such a method and also an
apparatus for
performing such a method.
Methods of adhering an adhesive to a fabric piece are known. Such methods
typically
comprise heating the adhesive and pressing it into contact with the fabric
piece to form a
bond. The problem with certain such methods can be the limited time available
to form a
bond between the adhesive and the fabric piece.
With flat fabric pieces this problem can be partially overcome by adhering the
adhesive
in a two step process. Firstly the adhesive is warmed to make it tacky then
positioned on
the fabric piece where it forms a weak bond. The fabric piece/adhesive
composite is then
placed in a flat bed press where it is further heated and pressed until an
effective bond
forms. This process is however slow.
Curved fabric pieces, for example knicker legs or bra cups, can be more
difficult. With
curved fabric pieces the fabric piece and adhesive film are passed typically
though a pair
of narrow heated plates which heat the fabric piece and film to the desired
temperature.
The curved fabric piece can however only be passed slowly through the plates
due to the
time it takes for a bond to form.
1
CONFIRMATION COPY
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
The method according to the invention seeks to overcome the problems
associated with
the prior art.
Accordingly, the present invention provides a method of adhering an adhesive
to a fabric
piece comprising the steps of
providing a fabric piece;
pre-treating a portion of the fabric piece to increase its surface
wettability; and,
pressing the adhesive and the pre-treated portion of the fabric piece
together.
The method according to the invention enables a bond to be formed between the
fabric
piece and adhesive more rapidly than known methods. This improves the
throughput of
machines for adhering adhesive to fabric pieces, so reducing manufacturing
cost. It also
enables fabrics to be used which hitherto were incapable of being effectively
bonded.
At least one of the pre-treated portion of the fabric piece and adhesive can
be heated
whilst the pre-treated portion of the fabric piece and adhesive are pressed
together.
At least one of the pre-treated portion of the fabric piece and adhesive can
be pre-heated
prior to being pressed into contact with the other.
The step of pre-treating the portion of the fabric piece can comprise
roughening the
surface of the portion of the fabric piece.
The step of pre-treating the portion of the fabric piece can comprise exposing
the surface
of the portion of the fabric piece to a plasma.
The plasma can be a neutral plasma.
2
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
The step of pre-treating the portion of the fabric piece can comprise etching
the surface of
the portion of the fabric piece with an etchant.
The step of pre-treating the portion of the fabric piece can comprise coating
the surface of
the portion of the fabric piece with a hydrophilic coating.
The step of pre-treating the portion of the fabric piece can comprise coating
the surface of
the portion of the fabric piece with a primer.
The method can further comprise the step of adhering the side of the adhesive
remote
from the pre-treated portion of the fabric piece to a portion of a second
fabric piece.
The portion of the second fabric piece can be preconditioned to increase its
surface
wettability.
The pre-treated portion of the fabric piece and the pre-treated portion of the
second fabric
piece can be spaced apart portions of the same fabric piece.
The adhesive can be a film.
The adhesive can be a thermoplastic, preferably polyurethane.
The adhesive can be a coating on a_tape.
Preferably, both sides of the tape are coated with an adhesive.
In a further aspect of the invention there is provided a composite structure
comprising
a fabric piece, a portion of the. surface of the fabric piece having a greater
surface
wettability than the surrounding surface; and,
3
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
an adhesive bonded to the portion.
Preferably, the composite structure further comprises a tape bonded to the
opposite side
of the adhesive to the portion of the fabric piece.
In a further aspect of the invention there is provided an apparatus for
adhering an
adhesive to a fabric piece comprising
first and second plates having a gap therebetween;
a displacement means for drawing a fabric piece and an adhesive between the
plates where they are pressed together;
a pre-treating means for pre-treating a portion of the surface of the fabric
piece to
increase its surface wettability before being received by the plates.
The pre-treating means can be adapted to roughen a portion of the surface of
the fabric.
The pre-treating means can be adapted to expose a portion of the surface of
the fabric.
piece to a plasma, preferably a neutral plasma.
The pre-treating means can be adapted to etch a portion of the surface of the
fabric piece
with an etchant.
The pre-treating means can be adapted to coat a portion of the surface of the
fabric piece
with a hydrophilic coating.
Preferably, the apparatus comprises a heater for heating at least one of the
adhesive and
fabric piece prior to being received by the plates.
Preferably, at least one of the plates is heated.
4
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
The present invention will now be described by way of example only and not in
any
limitative sense with reference to the accompanying drawings in which
figure 1 shows an apparatus for adhering an adhesive to a fabric piece by a
method
according to the invention in schematic cross section; and,
figures 2(a) to 2(d) show composite structures produced by methods according
to the
invention.
Shown in figure 1 is an apparatus 1 for performing a method according to the
invention in
schematic cross section. The apparatus 1 comprises first and second plates 2,
3 having a
narrow gap 4 therebetween.
A displacement means (not shown) draws a film of adhesive 5 through the gap 4
as
shown. The adhesive 5 is typically a thermoplastic adhesive 5, preferably
polyurethane.
As the film of adhesive 5 is drawn towards the gap 4 it is preheated by a
preheating
apparatus 6. The pre-heating apparatus 6 may comprise a hot plate over which
the film 5
is drawn. In alternative embodiments the pre-heating apparatus 6 provides one
or more
jets of hot air which heat the film of adhesive 5. The heating of the film of
adhesive 5 is
sufficient to make it tacky.
A fabric piece 7 is also drawn into the gap 4 by a displacement means (not
shown).
Before the fabric piece 7 reaches the gap 4 it passes proximate to pre-
treating means 8
which pre-treat a portion of the fabric piece 7, increasing its surface
wettability.
In the current embodiment the pre-treating means 8 pre-treats a portion of the
fabric piece
7 by exposing its surface to a neutral plasma. This causes chemical changes in
the
surface, increasing its wettability.
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
When the pre-treated portion of the fabric piece 7 and the heated film of
adhesive 5 reach
the gap 4 they are pressed into contact by the plates 2,3, bonding the
adhesive 5 to the
pre-treated portion of the fabric piece 7. The increased surface wettability
of the pre-
treated portion of the fabric piece 7 enables a bond to be formed between the
adhesive 5
and pre-treated portion more rapidly than with known methods so increasing the
throughput of the apparatus 1 and reducing manufacturing costs.
In alternative embodiments of the invention (not shown) alternative pre-
treatment means
8 are provided. In one embodiment the pre-treatment means 8 etches the surface
of a
portion of the fabric piece 7 with and etchant. In an alternative embodiment
of the
invention the pre-treatment means 8 coats the surface of the portion of the
fabric piece 7
with a hydrophilic coating. In a further alternative embodiment of the
invention the pre-
treatment means 8 roughens the surface of the portion of the fabric piece 7.
In a further
alternative embodiment of the invention the pre-treatment means 8 singes the
surface of
the portion of the fabric piece 7. In a further alternative embodiment of the
invention the
pre-treatment means 8 exposes the surface of the portion of the fabric piece 7
to ozone,
typically generated by an electric spark.
In the above embodiments the adhesive 5 is provided as a film to the pre-
treated portion
of the fabric piece 7. In an alternative embodiment the adhesive 5 is a
coating on a tape 9.
The adhesive 5 bonds the pre-treated portion of the fabric piece 7 and tape 9
together,
strengthening the fabric piece 7.
In an alternative embodiment of the invention the method is performed twice.
In a first
step the adhesive 5 is first bonded to a first pre-treated portion of a fabric
piece 7 by
passing it through the apparatus 1. The composite fabric and adhesive is then
passed
through the apparatus I again with a second fabric piece 10, a portion of
which has been
pre-treated. The fabric pieces 7,10 are arranged such that the layer of
adhesive 5 is
sandwiched between the pre-treated portions of the fabric pieces 7,10 . As the
fabric
pieces 7,10 pass through the apparatus 1 the adhesive 5 bonds the pre-treated
portions of
the two fabric pieces 7,10 together. The resulting structure is shown in
figure 2(a). A
6
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
similar method is also possible using a layer of adhesive 5 on both sides of a
tape 9. In a
first pass through the apparatus 1 one side of the tape 9 is bonded to a pre-
treated portion
of a first fabric piece 7. In the second pass through the apparatus 1 the
opposite side of
the tape 9 is bonded to pre-treated portion of a second fabric piece 10. The
resulting
structure is shown in figure 2(b). The first and second pre-treated portions
may be
separate portions of the same fabric piece 7. The resulting structures are
shown in figures
2(c) and 2(d).
In an alternative embodiment of the invention both bonding steps are performed
simultaneously. If the first and second pre-treated portions are portions of
the same fabric
piece 7 this can be achieved by passing the fabric piece 7 through a fabric
folder (not
shown) to sandwich the layer of adhesive 5 (or tape 9 having an adhesive 5 on
both sides)
therebetween before passing the composite structure through the plates 2,3.
In an alternative embodiment of the invention the first and second bonding
steps are
performed by passing the fabric piece 7 and adhesive 5 through a first
apparatus I to
bond the adhesive 5 and first pre-treated portion of the fabric piece 7
together. The
resulting composite structure is then passed along with a second fabric piece
10 through a
second apparatus I where the adhesive 5 is bonded to a second pre-treated
portion of the
second fabric piece 10.
In all of the above embodiments the adhesive 5 is heated before being passed
through the
plates 2,3. In alternative embodiments the plates 2,3 are heated so that they
simultaneously apply both heat and pressure to the pre-treated portion of the
fabric piece
7 and adhesive 5 passing between them.
In an alternative method according to the invention the portion of the fabric
piece 7 is
pre-treated and then bonded to the adhesive 5 in a flat bed press.
In an alternative method according to the invention ink is printed in a
pattern on a sheet,
typically a paper sheet. An adhesive 5, typically a powder adhesive 5, is
adhered to the
7
CA 02729196 2010-12-23
WO 2010/007340 PCT/GB2009/001538
ink. The adhesive 5 is then pressed into contact with the pre-treated portion
of the fabric
7 forming a bond. Finally, the paper is removed revealing the ink pattern on
the fabric 7.
In an alternative embodiment of the invention the adhesive 5 is polyester.
8
