PROCESS FOR STRUCTURING FLAT ARTICLES

METHODE DE REPOUSSAGE SUR ARTICLES PLANS

English Abstract

ABSTRACT OF THE DISCLOSURE
The invention provides a process for structuring flat
articles. In this process the flat article is irradiated with
high energy beams, contacted with monomer substances and, if
required, treated with a shrinkage medium. The invention obtains
a structured flat article in a single-stage process by a process
in which prior to the irradiation with high energy beams the
flat article is subjected to thermal treatment, which varies
over the surface, for example, heat-setting. A flat article
having three-dimensional patterns is thus obtained.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for structuring flat articles, in which
the flat articles are irradiated with high energy beams and
monomer substances are grafted onto said articles, and in which
prior to the irradiation with the high energy beams the flat
article is subjected to thermal treatment which varies over the
surface.
2. A process as claimed in claim 1 in which the
grafted articles are subsequently contacted with a shrinkage
medium.
3. A process according to claim 1 or 2 in which
the thermal treatment is a heat-setting treatment.

Description

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The present invention relates to a process for
structuring flat articles in which the flat articles are
irradiated with high energy beams, whereupon monomer substances
are yrafted onto the flat articles and, if required, the flat
articles are then contacted with a shrinkage medium.
The embossing of fabric~ of synthetic fibres is
known (Wirkerei-und Strickerei-Technik, 1965, no. 4, page 198-
200). The effect is attained by a combined treatment with pres-
sure and heat. It is also known to attain patterning by local
shrinkage (Internat. Textil-Bulletin Farberei/Ausrustung, 1970,
no. 3, page 248). In this case the tendency of differently heat-
treated materials to shrink is utilized by the combination of a
calender and washing machine in full width. The disadvantage of
this process lies in that the dye affinity, the moisture sorption
and the antistatlc behaviour are not improved simultaneously on
attaining an ornamental structure pattern.
It is also known that flat articles can be structured
in that monomer substances are grafted onto the flat article so
as to be restricted locally. If required, these grafted-on monomer
substances are sub~ected to an after-treatment resulting in vary-
ing degrees of shrinkage of the graEted and non-grafted regions
of the flat article and thus producing a pattern (East German
Patents 81839, 86086, 86161, 9S827 and 111226). These processes
have the disadvantage that the antistatic effect can be attained
only by a two-stage process.
The present invention obtains in a single-stage process,
structured flat articles which have an improved dye affinity and
moisture sorption simultaneously with an improved antistatic
behaviour.
Thus the present invention attains the stage of the
locally reinforced grafting by a novel process step.
According to the invention prior to the irradiation
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with high energy beams a flat article is subjected to a varying
thermal treatment.
According to the present invention therefore there i9
provided a process for structuring flat articles, in which the
flat articles are irradiated with high energy beams and monomer
substances are grafted onto said articles, and in which prior
to the irradiation with the high energy beams the flat article is
subjected to thermal treatment, which varies over the surface.
It is advantageous to carry out the thermal treatment
as heat-setting of the flat article. The diffusion of liquid
media in solid substances is determined, inter alia by the
structural state of the solid substance. This state can be
changed in a controlled manner either homogeneously or partially.
If the state is changed partially, then the diffusion of the
liquid media in the solid substance can be assigned to the
structural state concerned. If the liquid media are, for example,
radiation-chemically polymerizable substances, then a poly-
merization which quantitatively varies locally can occur.
Depending on the polymerizable substance used, even during the
polymerization process there is a difference in tension between
the more or less grafted regions and the solid substance forms
a macroscopically visible texture. This effect can still be
controlled by the extent of the difference between more or less
grafted regions. However, if the differences in tension are
too small to cause a macroscopically visible structure, then the
effect on the grafted monomer can be increased by a subsequent
chemical reaction during further modification processes.
It is considered surprising that the structure is
changed prior to the irradiation with high energy beams by a
treatment which varies over the surface to such an extent that
a pattern effect is produced by the subsequent treatment.
The present invention will be further illustrated by
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way of the following examples.
EXAMPLE 1:
A PA flat warp fabric having the surface mass of 90 g
per sq. m is subjected to a treatment with an embossing calender.
By embossing calendering is meant that the relief
pattern of an embossing roller presses against a substantially
non-deformable counter-roller. The non-set PA flat warp fabric
is embossed at a temperature of 185C and at a rate of 15 metres
per minute. The roller pressure is set at 150 p per cm. The
material thus pretreated is then contacted with acrylic acid and
irradiated with high energy beams. The acrylic acid has a
concentration of 15% and a temperature of 30C (time of impregna
tion 5 minutes). An electron accelerator is used for the
irradiation, the dosage being 4 Mrad. This is followed by
rinsing and drying. The products thus obtained show a visible
three-dimensional pattern. These products can be reinforced in
their patterns if the grafted-on acrylic acid is converted into
its salts. It is also possible to modify fibre threads instead
of the fabrics. The pre-irradiation method can also be applied
instead of the simultaneous method described.
EXAMPLE 2:
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A plain weave fabric made of PA-S and having a surface
mass of 125 g per sq~ m is thermally pretreated as in Example 1.
The material thus pretreated is contacted with acrylic acid and
irradiated with high energy beams. The acrylic acid has a
concentration of 10% and a temperature of 60C (time of impregna- ;
tion 3 minutes). An electron accelerator is used for the irradia-
tion, the power being 600 KeV and the dosage 2 Mrad. This is
followed by rinsing and drying. The products thus obtained have
a visible three-dimensional pattern.