Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1056708
Thls lnventlon relates to n multl-layered composite
textile material which contalns at least two layers of thermoplastic
welded together intermittently, for example, by spot welding. Additional
structure i9 incorporatcd lnto the textile material and imparts new
propertles thercto whlch are not present ln known materials such a~
woven fabrlcs, knlts or non-woven textlles.
Composite materials comprising several thermoplastic
sheets welded together intermittently, as for example by spot weldlng,
are known.
Also prevlously suggested are numerous ways of combining
non-woven te~tlles having thermoplastic bindlng fibres by spot application
of pressure at high temperature. The materials thus obtalned vary in
softness or rigidity, as well as elastlcity, depending on the ~ind and
quality of the threads employed and on the form and density of the welds,
and also on any bondlng agent that may be added.
~ oven ~abrics and knits obtained by cross-weaving of warp
and woof threads or intertwining of continuous threads are also known
for the production of multi-layered composite materlals.
Also known are textile materials in the form of "thread
lays," i.e. longitudinally or transversely laid groups of threads which
are ~oined together. There have been numerous suggestions relating to a
very wide variety of mechanical devices for preparing and bringing to-
gether the warp and woof threads of the lay in a uniformly parallel
arrangement. Joining of the threads together is also known, the simplest
method conslstlng of immerslon of the prepared lay ln an emulsion of
bonding agent followed by drying. However this produces a stlff product
coated on all sldes wlth bonding agent.
In DT-AS (German Published Speclflcatlon) 1,120,421 another
prOCeS8 18 suggested ln whlch the bonding of the longltudlnal and trans-
verse threads is confined, by the use of dlfferent flbre materlals and
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1056708
swelling agents, to the actual points of intersectlon. This l~provesthe softness of the product. The lay is "slide-fast".
All hitherto known thread lays have the distlnct disad~
vantage that unlike woven fabrics snd knits the points of intersection
o the threads are fixed or "frozen". Because of the bonding the lays
lose the relative mobility of the longitudinal and transverse threads.
In the present invention a multi-layered composite textile
material is provided whlch contains at least two thermoplastic sheets
welded together intermittently, as for example by spot welding. The
material is characterized by at least one group of longitudinally and/or
transversely laid threads, a so-called "thread lay", which is coated on
both sides by at least one thermoplastic layer, the thread being fixed in
its geometric position by thermal welding together of the coating layers
in the interstices, while the threads remain axially mobile. The compo-
site material thus comprises a thermally welded multi-layered structure
in which an unbound thread lay is so embedded by intermittent welding
that all threads remain freely mobile in their axial directions. The
invention thus provides a "slippable" thread lay in which the points of
intersection of the threads are not "frozen".
In its 6implest form the multi-layered composite material
accordlng to the invention comprises upper and a lower thermoplastic
layers which can be welded and a thread lay disposed therebetween. There
may also be a succession of such layers in sandwich form, such that at
least one weldable thermoplastlc layer always alternates with a thread
layer, one over the other, the top and bottom outside covering layers
being of thermoplastically weldable mater~al.
Especially suitable a~ weldable thermoplastic layers are
sheets oP non-woven textile matesial containing thermoplastlc binding
flbres. Also approprlate, however> are woven fabrics or knlts as well as
weldable thermoplastlc foils. If deslred, more than one thermoplastic
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1~56708
lsyer can be disposed between the thread lays. If the composlte material
is to be waterproofed on one or on both sides, it is recommended that the
side which will be exposed to moisture be furnished with a thermoplastic
sheet in the form of a plastic ~oil.
According to the invention the thermoplastic layers, e.g.
layers of non-woven textile materials, are welded in the interstices of
the thread lays, that is in the spaces containing no threads, snd because
of this the structure has the necessary reinforcement but the axial
mobillty of the threads is retained. The thread lays as such, are per-
manently ixed in their prescribed geometric configurations. The composite
msterial may be constructed of one or more thread lays, the threads of
which, however, are not fixed by bonding agent so as to have fixed thread
intersections. For many applications, fixed thread intersections in
known thread lays are considered to be a disadvantage.
Fixing of the threads of the lay in axial direction within
the composite material of the invention is achieved by static friction.
The strength of traditional textile flat goods where no chemical cementing
is employed in the finishing, is due entirely to static friction between
individual fibres or threads. Since the frictional force ls a function
of the contact pressure, contact area and the coefficient of friction,
these factors are increased, particularly where high mechanical strength
of the threads is required by for example high twists, brightening and
tight linkage. In the composite materials of the invention the force
opposing the slippage of a thread in its longitudinal direction ls
determined by the thickness of the thread itself, lts surface, the distance
between the weld points of the thermoplastic covering layers and the
weights of the layers. With a knowledge of the6e factors the composite
materials according to the invention can be designed to suit the particular
application.
For many nppllcatlons lt has been ~ound useful to construct
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1056708
the thread lays from threads of different gauge. In this way materials
are obtained which are used for instance for the manufacture of llning
msterials, cushioning materials or the like.
A 6uitable design further consists in the use of shrinkable
fibres for the non-woven textile constltutlng the thermoplastic covering
layers. During welding these flbres shrlnk and the enclosed threads or
thread lays are embedded under stress.
The thread lay comprises textile threads of the desired
character and gauge and/or mineral or metalllc threads. The addition of
or excluslve use of metallic threads results ln electrlcally conductive
composite materlals. These goods may be made into electrlc blankets,
electric bandages, heatlng draperles or other such ltems. The electrlcal
reslstance can be varied by varying the amount of metallic threads and
can thereby be adapted to the lntended application. On account of the
mobility of the thread lay it is possible to change the resistance by
the removal of individual threads, for example in the application to
electrlc bandages.
Compared wlth known thread lays, woven fabrics, knit goods
and fleeces, the present composlte textlle materlal shows distlnct ad-
vantages. It ls posslble to produce composite materlals ln whlch one
thread directlon is strongly preferred~ a property whlch ls desired for
example for conveyer belts, drlve belts and fiubstltutes for wool llnlngs.
The second group of threads (e.g. woof) normally requlred for the
geometrlc fixation o~ the first group (e.g. warp) can be dlspensed ~ith.
Optical density or opac~ty of the materials is not achieved
in the composlte material of the invention by means of a very thick layer
of threads, which would be expensive compared to flbre fleeces. Unlike
the known thread lays, woven fabrics or knits, the composite materlals of
the invention are diagonally stable and comparatlvely non-stretchable in
811 directions.
1056 708
The following examples descrlbe embodiments of the
composite material according to the invention but are to be taken as
illustrative of the invcntion and not as limiting to its scope.
Example I
To form a composite material according to the present
invention 5 parallel, longitudinally oriented contlnuous viscose yarn
threads of 600/12 den. were disposed per 1 cm width.
The longitudinal threads were placed between fleece layers
each of 70% polyamide 66 fibres 3.3 dtex and 30% polyamide 6 fibres 3.3
dtex. The two fleece layers were spot welded in the spaces between the
longitudinal threads~ i.e. at intervals of 2 mm, the separate weld spots
being 0.6 mm long and 0.8 mm wide with a longitudinal spot interval o
1.43 mm. The welded spots occupied 17% of the total area of the composite
material. Each thread was encased on both sides by fibres which are
anchored at the weld spots and was fixed in lts position by the coaction
of fibre tension and coefficient of friction bet~een the thread and the
surface of the flbre.
This composite material, impregnated with polyamide
adhesive, has been used successfully ln the men~s wear industry as a patch
reinorcement lining, where the resilience of the longitudinal threads
which are still mobile within the fleece has particular importance.
A strip of the composite material 5 cm wide and 10 cm long
was placed in 8 tenBile-test machine ln such a way that the upper clamp
gripped 10 thread~ witll no fleece while the lower one held the entire
width of the fleece with the remainlng lS threads. The force needed to
move the threads ln their longitudinal direction was measured at 23.3 p,
i.e. 2.33 ponds per thread. (I pond ~ tlle force of lg. of mass at a
standard acceleration due to gravity).
1056708
Example 2
A composite material was prepared as ln Example 1, but
with the binder fibre increased to 50% and the number of longitudinal
threads increased by 50% by insertlng a second thread in every second row.
When messured by the method described in Example 1 for
testing tensile strength it was found that 4.66 p was expended for the
longitudinal moticn of a single thread of the composite materlal, while
a double thread required a force of 5.56 p.
Example 3
Another composite material according to the invention was
made as follows:
Two groups of threads comprising polyester continuous
threads running side by side at intervals of 1.25 mm with 25 capillaries
and a total tlter of 140 dtex were laid one over the other at an angle of
90. Below and above the thread lay was placed a fibre fleece of 30 g/m
comprising 100% polyamide 66 - 6 core-mantle fibres 3.3 dtex/60 mm, and
the two 1eeces were thermoplastically welded together exactly in the
meshes of the thread lay. The weld spots measured 0.30 x 0.30 mm (square)
and the total welded area was 5.76% of the total area of the material.
This composite material was distingulshed by a soft feel
and short stretch. The so-called "plywood effect", to be avoided in
laminated cloths, was absent because the embedded threads were mobile
with respect to each other and with respect to the outside layers. However
in such composite material the threads provide high strength and short
stretch, and when used, for example, for outer garments prevent bagging
st the knees or elbows of the kind observable with non-woven textile
materials or felts.
Example 4
Anothcr composlte materlal made according to the lnventlon
comprised two fleece layers o the following flbre mixture: 70 parts
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1056708
.
polyester 1.4/40 (1.5 dtex, 40 mm length) and 30 parts unstretched poly-
ester fibres (whlcl- have a lower softening polnt than the st~etched flbres),
plu8 a number of copper strand wires each having 10 strands of 0.05 mm
diameter laid between the fleece layers. The electrical resistance of
the wire was 9.07 n/m. The weight of the fleece was 30 g/m2 on one side
and 60 g/m2 on the other. The distance between wires was 5 mm. The
layers were firmly spot welded to each other, the copper wires being
situated exactly between two rows of weld spots so that while locally
fixed in the composite material and insulated externally by the fleece
layers, they were not damaged in any way by the pressure required for
welding.- The described composite material was flexible like a textile
and could be used for making electric blankets, electric banda~es and
heating draperies.
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