Note: Descriptions are shown in the official language in which they were submitted.
l ~ ~21 1 5
The present i.nventi.on relates to elastic yarns designed
to be added to soft backi.ngs wi.th a view to forming a gather in
at least parts thereof.
The technical fi.eld concerned i.s, more particularly but
not exclusively, that of clothing i.n general, i.e. i.ncludi.ng all
the elements whi.ch can be deemed to contribute to the
protecti.on, the adornment, the dressi.ng and/or the ornamentation
of all or part of the human body, whether or not these elements
are visible.
In the aforesaid techni.cal fi.eld, it is known to
produce items of clothi.ng which have, either i.n parts, or along
edges, elasti.cally deformable gathered areas by which they are
adequately held on the body wi.th no interference to the wearer.
Up to now, i.t has been known to produce types of hems
wherei.n elasti.c yarns are introduced and immobi.lized by tensi.on
stitchi.ng, so that when the tension is released the result is a
gathering. Another known method consists also in weaving,
locally at least, a stretched elasti.c yarn with the yarns
consti.tuti.ng the i.tem of clothi.ng, so as t.o produce, after
slackening, a gatheri.ng which i.s perpendi.cular to the line of
elasti.c yarn.
The aforesai.d methods present certai.n advantages but
they are not practi.cal to use when the element consti.tuti.ng the
i.tem of clothing i.s a sheet or strip of woven or non-woven
synthetic materi.al. Such methods are not sui.table either for
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the mass-production of articles as they do not allow fast rates
of production.
In the above cases, it has been proposed to replace the
known soluti.ons by fitti.ng an elasti.c band consti.tuted by a flat
yarn attached by adhesi.ve means to the support desi.gned to
receive it.
The manufacturi.ng techni.que which is known in this
fi.eld consists in arranging for a strPtched flat yarn to unwind,
said yarn containing adhesive spots. In a subsequent operation,
the yarn is laid on the support and held i.n contact therewith by
the appli.cati.on of a pressure and a temperature designed to
polymerize the adhesive.
Such a manufacturing technique is not suitable for
mass-production as it is necessary to provide a relatively
complex installation for the unwindi.ng and stretchi.ng of the
flat elasti.c yarn, and for depositing the adhesive spots by
means of small si.zed nozzles, in order to prevent the glue from
formi.ng threads or from running.
Besides the high cost of these i.nstallati.ons, thei.r
complexity also necessi.tates di.ffi.cult maintenance whi.ch can
often i.nterrupt producti.on li.nes i.n the mass-producti.on of
arti.cles for wi.de di.stri.bution.
It i.s an object of the present i.nvention to mi.ti.gate
the aforesai.d problems by providi.ng novel elasti.c yarn having
the particular feature of being provided wi.th means for joining
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i.t to a support, so that yarn ana the support can be joi.ned
together easi.ly at hi.gh speed, i.n mass-production lines, wi.thout
necessi.tati.ng the use of substanti.al additional equipment which
is expensi.ve and complex to mai.ntain.
The i.nvention provides thermo-adhesive elasti.c yarn
designed to be applied and attached to a backing and comprisi.ng
an elongate elasti.c element associated wi.th at least one second
elongate element and forming with the second elongate element an
elastically stretchable combination, the second elonyate element
being adapted to be at least partly moved relatively to the
fi.rst elongate element and the second element bei.ng coated a
thermo-adhesi.ve substance at least at spaced locations along the
second elongate element.
The i.nvention will be more readily understood on
lS readi.ng the followi.ng descri.pti.on of embodiments t.hereof with
reference to the accompanying drawi.ngs, in whi.ch:
Fi.gure 1 is a partial vi.ew of an elastic yarn embodyi.ng
the inventi.on, bei.ng stretched.
Fi.gure 2 is a si.mi.lar vi.ew to Figure 1 showi.ng another
embod;.ment of the present yarn.
Fi.gures 3 and 4 are partial elevat.i.onal vi.ews showi.ng
two other possi.ble embodiments of the invention.
Fi.gure 1 shows that, according to the first i.llustrated
example, the present yarn compri.ses an elasti.c core 1 i.n any
suitable materi.al, whi.ch can be of circular cross-section,
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preferably, or i.n some cases, of square or rectangular
cross-secti.on, then consti.tuting a sort of elastically
deformable ribbon.
The core 1 i.s associ.ated with a wrapping yarn 2 whi.ch
is wound into successi.ve heli.cal coils, whi.ch coils can be
mutually adjacent when the core 1 is not stretched. The
wrapping yarn 2 may be a mono-fi.lament or multi-filament,
natural, artificial or syntheti.c fiber.
The wrappi.ng yarn 2, herei.nafter referred to as the
external wrapping yarn, is associ.ated with a thermo-adhesive
substance, deposited, at least at spaced locati.ons, on the coils
3. Preferably, the thermo-adhesive substance i.s composed of a
resin, such as for example, that commercialized under the
trademark 'ELVAX 4310' whi.ch can be defined as being an
ethylene/vinyl acetate/organic aci.ds terpolymer. The
thermo-adhesi.ve substance can be deposi.ted i.n several suitable
ways on the coils 3, or it can alternati.vely be coated over the
entire surface of the external wrappi.ng yarn.
It is also possi.ble in certai.n cases to deposi.t the
thermo-adhesive substance on the coi.ls 3 after these have been
wound on the core 1.
The elasti.c yarn covered as explained hereinabove can
be stretched before being appli.ed on a support. As illustrated
in Figure 1, the different coils, as a result, are relatively
spaced apart, consti.tuting then joi.ni.ng points with the support
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by way of the thermo adhesive substance with which they are
coated. The application and joint at the interface level can
then be ensured in practical manner by passing the support and
the stretched covered yarn between the elements of a pressurized
applicator, in which the tmeperature is raised in order to
soften the thermo-adhesive substance sufficiently to make
pinpoint joints between the yarn and the support.
By way of example, when applying the elastic yarn on a
synthetic support such as in vinyl polychloride, the working
parameters to ensure a joint between the yarn according to the
invention coated with the product sold under the trademark
'ELVAX 4310' and the support, are as follows:
pressure.................... about 1 kg
temperature................. between 50 and 110C
duration.................... less than or substantially
equal to 1 sec.
When applying the yarn on a cotton support, the working
parameters applied are as follows:
pressure.................... about 1 kg.
temperature................. between 50 and 150C
duration.................... between 1 and 5 secs.
The tensile stress applied to the core 1 is of course
dependent of the characteristics of the material of the core and
of the desired gathering.
The covered yarn according to the invention is
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inexpensi.ve to produce and i.ts appli.cation on a support requires
no particularly complex or deli.cate i.nstallation for aeposi.ting
the spots of adhesive. As a result, the costs of production and
maintenance of the machines requi.red to apply such a yarn on any
type of support i.s consi.derably reduced. It also becomes
possible to set up conti.nuous production li.nes of articles or
clothing which can be mass-produced at lower costs.
Another advantage of the present elastic yarn resi.des
in that, as shown from experi.ence, a saving is made in the
amount of adhesive used, since the adhesi.ve substance may be
more wi.dely distributed than i.n pri.or art products and it is not
necessary to deposit large blobs of the adhesi.ve as in prior art
techniques.
The present yarn may be used in many fields, and more
parti.cularly i.n the clothi.ng field. In that fi.eld, the present
yarn is useful in parti.cular for the producti.on of babies
nappies, protective masks, caps, dust-covers, underclothes and
overalls.
Another field of appli.cati.on i.s t.hat of household linen
and i.n particular fitt:ed sheets.
Fi.gure 2 shows a modi.fi.ed embodiment wherei.n the yarn
compri.ses the core 1 on which a wrapping yarn 4, termed
'i.nternal', is wound i.n coi.ls 5 which are mutually adjacent when
the core 1 i.s not stretched. Preferably, the external wrapping
yarn 2, described hereinabove, is then wound around the assembly
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consti.tuted by the core 1 and the i.nternal wrapping yarn 4, in a
winding direction whi.ch i.s reverse to that of the yarn 4, so as
to obtain two guperimposed wi.ndi.ng layers.
Such a structure gives a well-balanced fi.nished yarn
and eli.minates ~he ri.sks of the core l kinking when this is only
associated to one wrapping yarn.
In certain cases, it may be recommended to use an
internal wrappi.ng yarn 4, which has the same material as the
external wrapping yarn 2.
In certai.n cases also, the i.nternal wrappi.ng yarn 4 can
be associated to a thermo-adhesi.ve substance deposited as
indi.cated herei.nabove, ei.ther at the level of the coils 5 prior
to the wi.nding of the external wrapping yarn 2, or else by pri.or
coating of the yarn 4. In such a case, the relative
pressurizing at a given temperature and for a predetermined
period between the yarn and the support enables the contact
points between the latter to be multi.pli.ed and also joi.ns the
coi.ls 3 and 5 together at their points of i.ntersecti.on.
Fi.gure 3 shows a further embodi.ment wherei.n the yarn
compri.ses an elasti.c strand la, shown in the drawi.ng as bei.ng of
ci.rcular cross-secti.on. It must be understood that any other
cross-secti.on is also suitable. The strand la, which plays the
part of the core l i.n the foregoi.ng examples, i.s associ.ated wi.th
a second strand 6 whi.ch can have the same composition as the
wrapping yarns 2 and 4 and be likewi.se previously coated with
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the thermo-adhesi.ve substance.
The strand 6 and the strand la are combi.ned by twi.sting
and throwing when the elastic strand la is stretched. The
resulting comb;.nati.on is constituted, when the strand la ;.s
slackened off, by a succession of adjacent coils 7 and 8 of the
elasti.c strand la and the strand 6 in alternate succession.
The aforesaid yarn i.s used as previously indicated by
stretching the combination so as to separate the different
successive coi.ls 7 and 8. The combi.nation thus stretched is
then placed on a support as previ.ously i.ndi.cated, pressure and
heat bei.ng appli.ed for a speci.fi.c period of time. This softens
the thermo-adhesive substance, at least where coils 8 are in
contact wi.th the support. The result i.s an assembly by
successive points of adhesi.on, whi.ch poi.nts become further
spaced apart from one another as the stretchi.ng force i.s
increased.
Fi.gure 4 i.llustrates another embodi.ment of the elasti.c
yarn according to the invention wherein the yarn compri.ses an
elastic strand lb whi.ch can be compared to the core 1. The
strand lb i.s stretched and combined wi.th a strand 9 whi.ch is
kni.tted to form successive sti.tches whi.ch are pulled when the
yarn is stretched as shown in the drawi.ng. The strand 9 can be
a si.ngle-fi.lament or a multi.-fi.lament, as aforedescribed, and is
coated, at least locally, with the thermo-adhesive substance
preferably before bei.ng kni.tted around the elastic strand lb.
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The resulti.ng pulled state of the combi.nati.on i.s
i.llustrated i.n Figure 4 to show that: i.n the yarn obtai.ned, there
is for each sti.tch, laterally to the strand lb, on the one hand
one 1OGP and on the other hand two, and that the lateral
distribution of these loops is reversed from one stitch to the
next. The different loops represent, after the aforesaid
application, joining points between the support and the
combi.nati.on via the thermo-adhesi.ve substance.
In the foregoi.ng, i.t is i.ndicated that the yarn is
pulled and then applied to a support. Thi.s joi.ni.ng method can,
i.t i.s true, be used over the enti.re length of a segment of yarn
which i.s to be enti.rely applied to a support, or over only part
of the length of such a segment whi.ch i.s also requi.red to form a
joi.ning element, such as a bar, loop, etc...
The inventi.on is in no way li.mited to the descri.ption
gi.ven hereinabove and on the contrary covers any modificati.ons
whi.ch can be made thereto wi.thout departing from the scope
thereof.
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