CA1122918A - Process for structuring flat articles - Google Patents

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.

Description

~12Z5~18 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 -1- ~

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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:

. _ _ 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.

Claims (3)

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.