Technical field

The technical solution relates to a textile for the protection of electronic information carriers which contains metal.

Background art

The problem of protecting electronic information carriers, especially from unauthorized access to this information, is becoming more and more worrying because the number of simple electronic information carriers is constantly growing and the data stored on them is personal data and is often misused. Such extremely vulnerable carriers include, for example, credit cards, travel or personal documents with machine-readable data and other simple carriers, but this also relates to smartphones and other more complex devices. The problem is that many of these devices have RFID or NFC or similar chips which allow to read the stored information remotely and completely without the owner's knowledge and gain this information, for example, for misuse. Moreover, the technical means needed for reading remotely this information can easily be bought in a shop or they are already included in numerous smart devices, such as NFC chips in smartphones and freely available NFC chip reader applications, etc.

For the contact between the reader and such an information carrier, radio broadcasting with specific power and on specific frequencies is used. An effective defence against unauthorized access to information on data carriers is provided by approaches based on the use of the Faraday cage principle, i.e. creating a barrier preventing the passage of electromagnetic radiation, i.e. including radio broadcasting.

Known solutions for protecting data carriers such as credit cards, means of personal identification (passports, identity cards with machine-readable data), mobile phones, tablets, etc., are based on the use of shielding materials, whether metal shielding foils or textiles with metallic elements, e.g., textiles with woven metal fibres, etc. A typical example is a solution according to US2006290501 A1 , US2006254815A1 , US2008000987A1 , US6845863B1 , US6121544A, US4851610A and others. With the aid of these known solutions, various cases for cards, passports, mobile phones, etc. are produced. However, their common disadvantage is relatively high sensitivity to repeated deformations, very high stiffness and low elasticity, which means that the products made from the known materials are non-deformable or complex packages or cases with protection zones interrupted at places where folds and other deformations of the packages occur.

The goal of the technical solution is to eliminate or at least to minimize the drawbacks of the background art, especially to develop a material having an adequate protective function, yet with low sensitivity to repeated deformations, low stiffness and high elasticity, which could be further processed by conventional textile manufacturing methods such as gluing, lamination, layering, sewing, etc.

Principle of the technical solution

The aim of the technical solution is achieved by a textile for the protection of electronic information carriers, whose principle consists in that it is formed by a planar and smooth composite non-woven textile whose fibrous part is made of synthetic fibres which are provided with a metal surface coating.

The textile thus produced can be attached by conventional textile techniques to other textile layers or between textile layers, typically by gluing or using polymeric interlayers or by lamination using a flexible matrix, etc. The composite non-woven textile itself, which is a functional element of the future product, exhibits very high air permeability (breathability), as well as uniquely low bending stiffness. These two important characteristics predetermine the suitability of the composite non-woven textile according to this technical solution for layering with other textiles which provide the composite non-woven textile with a protective function and ensure the desired visual effect of the resulting article. It is clear from the above that the functional layer according to the present technical solution does not in any way reduce both the flexibility and the transport characteristics of the entire resulting textile sandwich from which the final article is produced. Furthermore, the shielding effectiveness of the textile according to this technical solution reaches more than 45 dB for electromagnetic radiation in a sufficiently wide range of frequencies of 30 MHz to 20 GHz, the electromagnetic shielding effectiveness being constant over the entire frequency range. The textile thus produced can be used for producing cases for credit cards and other contactless information carriers, passports, identity cards, and for producing packages for electronic devices, cases for personal documents, etc.

Description of drawings

The technical solution and its effects are schematically represented in the drawing, where Fig. 1 shows comparison of the air permeability of the composite non-woven textile (PES/Cu) according to this solution with conventional textiles (T), knitted textiles (P) and polyester textiles coated with a layer of conductive polymer (PES/Cu), Fig. 2 shows comparison of bending stiffness of the composite non-woven textile (PES/Cu) according to this technical solution with conventional textiles (T) and polyester textiles coated with a layer of conductive polymer (PES/Cu), Fig. 3 illustrates electromagnetic shielding effectiveness of the composite non-woven textile (PES/Cu)/Cu) according to this solution depending on the frequency of electromagnetic radiation - evaluated according to ASTM 4935-10 standard, Fig. 4 is a microscopic image of the composite non-woven textile according to the present solution showing that the metallic sub-micron layer only envelops fibres, which results in a significant increase in the electrical conductivity accompanied by a considerable increase in the ability of the material to shield the electromagnetic field, without affecting negatively the basic textile characteristics which include, for example, transport characteristics (air and water vapour permeability and bending stiffness (flexibility)); and Fig. 5 is an example of the preparation of a textile sandwich comprising the composite non-woven textile according to the present technical solution as a functional element. Examples of embodiment of the technical solution

The technical solution will be described with reference to an exemplary embodiment of a textile for the protection of electronic information carriers, which is intended for common use as a processable textile layer of the final product, for example a protective case for electronic cards (credit cards, identity cards, etc.) or passports or mobile phones, tablets, etc.

The textile according to the technical solution is essentially a composite non-woven textile, wherein the fibrous part of the composite is made from synthetic fibres which are coated with a metal surface coating to form the resulting composite.

Prior to applying the metal coating, the surface of the non-woven textile undergoes treatment to make it flat and smooth, e.g., calendering, pressing, etc., since the flatness and smoothness of the surface reduces the occurrence of undesirable interference of electromagnetic waves on the surface of the textile fibres after the textile has been coated with the metal layer.

The material used for the non-woven textile as a raw material is preferably polyester, alternatively also natural materials can be used. The basis weight of the non-woven textile for the purpose of this technical solution is in the range of 5 g/m ² to 60 g/m ² and the thickness of the non-woven textile made for the purpose of this technical solution ranges from 50 μιτι to 200 μηι.

To achieve suitable shielding properties of the textile according to the technical solution, a chemical metal coating is applied to the textile fibres, for example silver, copper or tin, or at least two metals are applied simultaneously or sequentially. The preferred metal for coating is copper, which exhibits excellent shielding capability and mechanical bending strength, and last but not least, it has a favourable price. Other metals can be used as metals to provide corrosion resistance to copper. Applying a surface metal coating to the textile fibres, especially silver, copper and tin, is carried out by using appropriate techniques, e.g., some of the generally known chemical processes using autocatalytic methods. The metal to be applied has a character of a sub-micron layer which envelops only the textile fibres (not forming metal surfaces between the fibres), which results in a significant increase in electrical conductivity accompanied by a considerable increase in the ability of the material to shield the electromagnetic field, while not affecting the basic textile characteristics of the textile according to the technical solution, such as the transport characteristics (air and water vapour permeability at least 1000 lm ^"2 .s at an air pressure of 100 Pa and a bending stiffness (flexibility) of up to 0.5.10- ⁷ Nm ² ). The metal content (predominantly copper) expressed in g.m ^"2 of the textile is preferably in the range of 2 g.m ^"2 to 20 g.m ^"2 , more preferably in the range of 5 g.m ^"2 to 10 g.m ^"2 , which allow to achieve the shielding effectiveness of the textile at a level more than 45 dB with an absolutely constant value in the entire range of electromagnetic radiation frequencies used (30 MHz to 20 GHz), as shown in Figure 3.

The textile according to this technical solution thus forms a composite non-woven textile which is intended to be incorporated into the resultant article, preferably being protected on both sides by at least one other textile or non- textile layer, such as textile, knitted textile, non-woven textile, leather, artificial leather, foil, etc., these other layers being connected pointwise or in another manner, for example by gluing, sewing, etc.

In the exemplary embodiment of Fig. 5, two outer textile layers 1 between which the non-woven textile 2 according to the present technical solution is inserted are used in the final product, which is a protective credit card case, and all the three textile layers I, 2, 1_ are interconnected by stitching 4. From the sandwich thus formed, a protective textile case for a contactless credit card 3 is made by using conventional textile technologies, whereby the credit card 3 case preferably covers the entire surface of the protected credit card 3 or at least that part in which the contactless communication antenna of the contactless credit card 3 is located. It is obvious that the example of a credit card case is only illustrative and that the technical solution makes it possible to create effective protective cases and packages of different sizes, shapes, processing complexity, etc.

Industrial applicability

The technical solution is applicable for production of protective means for electronic information carriers, such as credit cards, identity cards, passports, electronic devices (mobile phones, tablets, laptops), etc., to protect them against unauthorized access and reading the information stored therein.