Note: Descriptions are shown in the official language in which they were submitted.
1~18~353
The present invention relates to a method for stiffen-
ing textile webs, in which fluid stiffening agent is applied by
screen printing, the thus treated web is dried and subsequently
undergoes further treatment, as well as to an apparatus for
effecting this method.
Methods are known by means of which textile webs are
stiffened by applying a stiffening agent. ~ccording to the
method disclosed in Swiss Patent No. 208 340 articles made from -
flexible fabrics are stiffened by applying a liquid, colourless
stiffening agent to the semi-finished or finished articles.
Following evaporation of the solvent this stiffening agent must
exert no adhesive action on adjacent layers of fabric. The
stiffening agent is applied in such a way that a graded stiff-
ness or flexibility is obtained or alternatively said stiffness
or flexibility varies according to the intended use. This
varying degree of stiffness is obtained by covering individual
areas of the articles when applying the stiffening agent, by
using solutions with different concentrations or by applying
different quantities of stiffening agent, for example by
spraying nozzles using a different pressure or by partly cover-
ing with varyingly thick wire netting during spraylng.
In the method disclosed in British Patent No. 911 517
a plastics material which can set or be cured under the action
of heat is applied to the article in the form of an aqueous
dispersion, emulsion or melt. By means of an engraved roller
or a hollow screen the stiffening agent is applied in varying
quantities, so that a different degree of stiffening is obtained
in individual portions of the article.
The use of known printing processes, e.g. relief,
intaglio or screen printing for applying the stiffening agent
to the textile web is proposed by the method disclosed in DOS
25 35 593.
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All the printinq processes for applying the stiffening
agent proposed in conjunction with these methods have disadvan-
tages. Quite apart from the fact that in these printing
processes the time required for applying the stiffening agent
is relatively long it is only possible to a limited extent to
adapt the metering to the particular textile web to be printed.
In addition, these printing processes are not suitable for
processing a stiffening agent which must be drop-forming and
not viscous in order to flow in a satisfactory manner into the
fibres. As a result these methods are time-consuming.
The present invention, whilst obviatinq the dis-
advantages of the aforesaid methods provides a method of the
type defined hereinbefore which reduces the printing time on
applying the stiffening agent to the textile web and permits
the application of a random stiffening agent metered in simple
manner and in varying thicknesses to different points of the
web, whereby in addition the screen printing form need only be
slightly larger than the web, whilst substantially eliminating ~ -
mechanical stresses on the screen printing form.
According to the invention there is provided a
method for stiffening textile fabrics in which a fluid stiffen- ;
ing agent is applied to the web by means of screen printing,
after which the web is dried and subsequently undergoes further
treatment. The improvement in which the textile web is gradually
placed under a screen printing form, whilst the stiffening agent
is distributed over the whole side of the screen printing form
remote from the textile web and its level is maintained spaced
over the screen printing form, whereby during screen printing ;
the thickness of the stiffening agent coating applied to the
textile web is controlled by the pressure acting on the screen
printing form.
In accordance with the present invention therefore
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the textile web is gradually placed under a screen printing
form, whilst distributing the stiffening agent over the complete
side of the screen printing form which is remote from the
` textile web and its level is kept spaced above the screen
printing form, whereby during screen printing the thickness of
the stiffening agent applied to the textile web is controlled -~
by the pressure acting on the screen printing form.
The invention also provides an apparatus for performing
the method according to the invention in which the textile web
-- 10 is placed on a gradually moved substrate over which is guided
a container for recelving the stiffening agent vertically
; towards and away from the substrate, whereby its base is formed
by the screen printing form and its remaining walls are con-
structed in gas tight manner, a pressure source being connected
to the container which permits the adjustment of the pressure
in the container.
The present invention will be further described
by way of the accompanying drawings, wherein:
Fig. 1 is a side view, partly in section, of a dia~
grammatically represented apparatus for stiffening a textile
web according to the embodiment of the present invention.
Fig. 2 is a plan view of the- apparatus according to
Fig. 1.
Fig. 3 is a vertical section through the screen print-
ing form and thè printing substrate on an enlarged scale, and
Fig. 4 is a plan view of the printing substrate.
The invention is based on the consideration that use
of a screen printing form although apparently suitable for
applying a stiffening agent to a textile web is too restricted
in its presently known form, particularly with respect to the
choice of stiffening ayent. Thus, although the present
invention uses a screen printing form for applying the stiffen-
1~87353
ing agent to the textile web, printing takes place in a modifiedmanner, as will be described in greater detail hereina~ter.
The apparatus for stiffening textile webs shown in
Fig. 1 substantially comprises a printing part 1 in which a
stiffening agent is applied to a textile web, and a drying and
after-treatment part 2. The latter is not critical to the
invention, so that its construction will only briefly be
- described. Part 2 could also be realized in some other way,
without having any effect on the invention.
The essential components of printing part 1 and drying
and after-treatment part 2 are covered by a housing 3 and
mounted on a machine frame 4. A supply spool 5 having the
shape of a six-sided prism is pivotably mounted on machine
frame 4. However~ it is also possible to use spools with a
different number of sides or in the form of a cylinder. The
supply spool 5 can also be replaced by some other conveying
mechanism, e.g. a conveyor belt.
The sides 6 of supply spool 5 serve to in each case
receive one of the portions to be treated, e.g. inserts for
stiffening and shaping items of clothing. In Fiy. 1 one side
6 of supply spool 5 with a web fixed thereto is located directly
below a pressure tank 8 which is guided in vertical manner on
a support 9. Pressure tank 8 is constructed in gas tight
manner and has on its base a screen printing form 10 which is
stretched over a frame 11 fixed to tank 8 ! e.g. by adhesion.
Screen printing form 10 can be made from a fabric of
silk, plastic, bronze or stainless steel or can be in the form
of a completely perforated screen. The fabric or screen is
patterned in known manner as a function of the stiffening
to be carried out, e.g. by photogravure and then forms the
base of the pressure tank. As a result of the patterning the
application of the stiffening agent takes place at specific
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points and with a specific mel:ering action.
The stiffening agent, which is relatively viscous, is
filled to a particular level into the inner area 12 of pressure
tank 8 and is kept at a substantially constant level by a not
; described regulating mechanism, e.g. by a float. Above pressure
tank 8 is arranged a storage tank 15 which is connected to
pressure tank 8 via a line 16 and a not shown metering device.
Storage tank 15 serves to supply stiffening agent to pressure
` tank 8 so as to maintain a constant level in the l~atter.
Pressure tank 8 is also connected via a line 20 to a diagram- -
matically represented pressure source 18. The pressure in the
inner area 12 is regulated by means of a diagrammatically
! represented pressure control system 22.
To enable the pressure tank 8 or the screen printing
form 10 arranged on the bottom thereof to be centred precisely
with the web held on the side 6 of supply spool 5 the pressure
tank is adjustably mounted in a frame 24 guided on support 9.
The adjustability of préssure tank 8 can for example be achieved
by means of a cross table-like construction used for machine
tools. `
Figs. 3 and 4 show that a printing substrate 26 is
fixed to slde 6 of supply spool 5. To this end adjustable stops
28 are provided in each side and serve for centering both the
printing substrate and the web. The stops 28 are under the
action of a not shown spring and are displaceable in a gap 30
inside 6. Thus, printing substrate 26 also covers ~ap 30 in
the area of web 7 to be treated. In turn web 7 is held on the
printing substrate 26 by a holding-down device 32, so that
after applying the stiffening agent the web does not stick to
the screen printing form lO.
The drying and aftertreatment part 2 comprises a
drying mechanism 34, e.g. a drying chamber, to which hot air
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is supplied by means of a blower 36. The web 7 to which stiffen-
ing agent has been applied is fed from supply spool 5 to a
conveying mechanism 38 which moves it through the drying chamber
34. After leaving the drying chamber 34 web 7 passes into a
condensing section 40 where it is heated to a higher temperature
to obtain the desired chemical reaction. The condensing section
40 can also have a conveying mechanism 42 by means of which web
7 is passed through the condensing section 40. In place of a
linear condensing section 40 it is also possible to use a
condensing drum. After leaving condensing section 40 web 7
passes into a stacking mechanism 44 from which it is conveyed
- away for further processing.
The above apparatus operates in the following manner:
Supply spool 5 places the web 7 applied to sides 6
below pressure tank 8, the latter being lowered until the
screen printing form 10 is just above or directly at the level
of web 7. By correspondingly regulating the pressure in the
inner area 12 of pressure tank 8 the screen printing form is
lowered onto the web 7. If the application of the stiffening
agent is to be interrup8ed the pressure is again changed, e.g.
by setting a vacuum so that the screen printing form 10 is
raised into the position shown in Fig. 3. After raising the
pressure tank 8 the further operation of supply spool 5 is
effected, so that the following web is brought below pressure
tank 8. The application of the stiffening agent now takes place
in precisely the same way as described hereinbefore. The
holding-down devices 32 on the bottom of supply spool 5 are
opened and the web is transferred to the conveying mechanism
38, drying and condensing then taking place in the manner
described hereinbefore.
It is essential that the stiffening agent is applied
by regulating the pressure in the inner area 12 of pressure tank
1~73S3
This eliminates substantially all the restrictions existing with
the known printing processes. It is possible to use a relatively
viscous stiffening agent and despite this the quantity thereof
to be applied can be very accurately metered. Numerous
possibilities exist for controlling the application of stiffening
agent, such as modifying the passage of the screen printing
form, the flow behaviour of the stiffening agent, the magnitude
and duration of the pressure and/or vacuum, etc. It would also
be possible to apply the stiffening agent by pressure regulation
on the back of a porous printing substrate.
In order to permit rapid changing of the screen print-
ing form 10 the stiffening agent can be sucked out of pressure
tank 8 by means of a not shown pump and can be returned again
after applying a new pattern.
When using the apparatus according to the invention
there are no restrictions regarding the use of different
stiffening agents. The desired metering can be obtained without
difficulty by choosing the most suitable pressure conditions
during application of the stiffening agent.
The term textile web is understood to mean layers or
parts of layers or punched out parts of knitted, woven or non-
woven fabrics.
The products suitable for stiffening and dimensional
stabilisation are those which under suitable conditions cannot
form a chemical bond with the web material used, with other
products applied to the web or with one another, whilst being
able to maintain the web dimensions stable during the reaction.
For this purpose it is possible to use the conventional products
of the textile industry, e.g. urea - formaldehyde precondensates,
melamine compounds, carbamides, acetals, compounds of the
ethylene urea, dihydroxydiethylene urea and dihydroxydimethyl
diethvlene urea types and all homologs thereof and similar
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i~873S3
substances either alone or in combination with other mentioned
products and/or in combination with a suitable catalyst. It is
possible to use as the catalyst organic or inorganic acids or
metal salts of an organic or inorganic acid, such as e.-g.
alkali metal or earth alkaline halide or an ammonium salt.
- It is also possible to use other product~- such as e.g. monomers
which can be reacted with the web material or with themselves
accompanied by a condensation or polycondensation, addition or
polyaddition or polymerisation or other chemical reactions
taking place with or without the splitting off of a further
reaction product, examples being styrene, ethylene, propylene
and the like.
The described process can be applied not only to the
stiffening treatment of textile webs and can also in fact be
combined with other treatments. It can advantageously be used
for producing inserts, required e.g. in the manufacture of
shirts and other items of clothing. These inserts are either
stiffened uniformly over the~ir entire surface or are stiffened
to a differing degree, for which purpose the above described
- 20 process is also suitable. Following stiffening said inserts
are generally connected in suitable manner with an upper material
for which purpose direct adhesion of the insert to the upper
material by means of thermo plastic adhesives with which e.g.
one side of the substrate is coated and has proved advantageously
suitable. Obviously coating can also take place on the upper
material. Independently of the point of application coating
takes place in punctiform or a real manner. The actual adhesion
is accompanied by pressure and temperature application, for
which purpose generally special pasting presses are used.
The described stiffening process can be extended in
such a way that lightly attached or loosely applied webs, e.g.
an upper material and inserts are stiffened together with the
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above-mentioned stiffeniny process. The stiffening agent must
be dried and condensed in a condensing section, whereby the
latter can easily be constructed in such a way that adhesion
of the web takes place simultaneously with the condensing of
the stiffening agent. Advantageously the condensing section is
constructed as a heating drum over which the web is guided and
simultaneously pressed.
In the case of fine upper materials it is impossible
to prevent the colour of the materials used for the inserts
showing through. Therefore it has proved necessary to maintain
stocks of materials with very varied colours so that an insert
or lining of the correct colour is available. This disadvantage
can be obviated in very simple manner through suitable dye
components being admixed with the stiffening agent. Thus, a
dye treatment takes place simultaneously with the stiffening
treatment in the case of the stiffening method according to the
invention.
If in the casé of inserts only certain areas are to
be stiffened by suitable choice of dye components it is possible
to dye only the stiffen~d areas. It is also possible to add
such dye components to the stiffening agent as do not adhere to
the latter and instead flow out of the same, thereby dyeing the
whole area of the insert. However, dyeing can also be performed
in a separate working process. The above-indicated process can
also be used for dyeing purposes, whereby the stiffening agent
is replaced by the dye which is applied to the screen printing
form in the pressure tank. After dyeing the whole area of the
insert, still without a stiffening agent, the substrate can be
stiffened, whereby once again the whole area or only parts
thereof can be stiffened, as desired. As the process is based
on a pressure action of the screen printing form, making the
use of a doctor unnecessary, said form can be sub-divided into
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different areas. On the side remote from the printing substrate
it is possible to apply different colours, so that the inserts
are printed simultaneously in multi-coloured form. If printing
takes place simultaneously with the stlffening treatment differ-
ent degrees of stiffness can be obtained in the different area
portions. Thus, inserts can in this way be produced, whose area
portions are on the one hand only printed with colour and on
the other are stiffened with dye-containing stiffening agents,
whereby the different treatment of the area portions takes
place in one and the same workiny operation.
As has already been stated the above-described
stiffening process can be extended so as to coat in punctiform
manner textile webs with thermo plastic adhesives, such as are
e.g. conventional with directly adherable inserts. All that is
necessary is a corresponding screen printing form. The adhesive
is applied to the side of the screen printing form remote from
the web in said pressure tank. Coating takes place in exactly
the same way as in the stiffening process by controlling the
pressure action. ~
Coating with the above-indicated adhesives can take
place before or after the dyeing or stiffening treatment or the
simultaneous dyeing and stiffening can take place in a separate
operation or continuously at an additional printing station.
Coating can thereby take place on one or both sides and over
all or part of the total area. It is also possible without
difficulty to coat all of one side and only certain areas of
the other side. Due to the fact that the thermo plastic puncti-
form application of the coating with the described process can
be distributed in random manner over the web a varying stiffness
distribution over the web is obtained.
As a result of the above-described extension of the
stiffening process the production of stiffened inserts and their
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use in conjunction with upper materials is further simplified.
A considerable time-saving and reduction of stocks are possible.
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