Method for manufacturing a water-insoluble pattern

Abstract

A method of manufacturing a water-insoluble pattern on and/or within a substrate is described. Also described, is a substrate obtained by such a method, a product including such a substrate and the use of the substrate in different applications.

Claims

1. A method of manufacturing a water-insoluble pattern on and/or within a substrate, the method comprising the following steps: a) providing a substrate, b) providing a treatment composition A comprising a deliquescent salt, c) providing a treatment composition B comprising an acid or a salt thereof, wherein the deliquescent salt of the treatment composition A and the acid or the salt thereof of the treatment composition B are selected such that the cation of the deliquescent salt and the anion of the acid or the salt thereof are capable of forming a water-insoluble salt in aqueous medium, and d) depositing the treatment composition A and the treatment composition B onto at least one surface region of the substrate to form at least one water-insoluble pattern on and/or within the substrate, wherein the treatment composition A and the treatment composition B are at least partially contacted and are deposited simultaneously or consecutively in any order, wherein the acid or the salt thereof in the treatment composition B is selected from the group consisting of hydrochloric acid, sulphuric acid, sulphurous acid, phosphoric acid, oxalic acid, tartaric acid, salts thereof, bicarbonates, carbonates, and mixtures thereof.

2. The method according to claim 1, wherein treatment composition A or treatment composition B is provided in liquid form.

3. The method according to claim 1, wherein the substrate is a planar substrate having a first side and a reverse side, and the treatment composition A and the treatment composition B are deposited onto the first side of the substrate, or the treatment composition A and the treatment composition B are deposited onto the reverse side of the substrate.

4. The method according to claim 1, wherein the substrate is a planar substrate having a first side and a reverse side, and the treatment composition A is deposited onto the first side of the substrate and the treatment composition B is deposited onto the reverse side of the substrate, or the treatment composition B is deposited onto the first side of the substrate and the treatment composition A is deposited onto the reverse side of the substrate.

5. The method according to claim 1, wherein step d) comprises the steps of: i) depositing the treatment composition A, and ii) subsequently depositing the treatment composition B, wherein the treatment composition A is contacted at least partially with the treatment composition B.

6. The method according to claim 1, wherein step d) comprises the steps of: i) depositing the treatment composition B, and ii) subsequently depositing the treatment composition A, wherein the treatment composition B is contacted at least partially with the treatment composition A.

7. The method according to claim 1, wherein the substrate is dried after step i) and/or step ii).

8. The method according to claim 1, wherein the deliquescent salt of composition A is selected from the group consisting of chlorates, sulphates, halides, nitrates, carboxylates, and mixtures and hydrates thereof.

9. The method according to claim 1, wherein the treatment composition A comprises the deliquescent salt in an amount from 0.1 wt. % to 100 wt. %, based on the total weight of the treatment composition.

10. The method according to claim 1, wherein the treatment composition B comprises the acid or the salt thereof in an amount from 0.1 wt. % to 100 wt. %, based on the total weight of the treatment composition.

11. The method according to claim 1, wherein the substrate is selected from the group consisting of paper, cardboard, containerboard, plastic, cellophane, textile, wood, metal, glass, mica plate, cellulose, nitrocellulose, cotton, marble, calcite, natural stone, composite stone, brick, concrete, tablet, canvas, natural materials of human or animal origin, and laminates or composites thereof.

12. The method according to claim 1, wherein the treatment composition A and/or the treatment composition B is/are deposited by electronic syringe dispensing, spray coating, inkjet printing, offset printing, flexographic printing, screen printing, plotting, contact stamping, rotogravure printing, powder coating, spin coating, reverse gravure coating, slot coating, curtain coating, slide bed coating, film press, metered film press, blade coating, brush coating and/or a pencil.

13. The method according to claim 1, wherein the water-insoluble pattern is a channel, a barrier, an array, a one-dimensional bar code, a two-dimensional bar code, a three-dimensional bar code, a security mark, a number, a letter, an alphanumerical symbol, a text, a logo, an image, a shape, a braille marking, or a design.

14. A substrate comprising a water-insoluble pattern obtained by a method according to claim 1.

15. The substrate according to claim 14, wherein the water-insoluble pattern is a hidden pattern, which is invisible when viewed at a first angle relative to the surface of the substrate, and visible when viewed from a second angle relative to the surface of the substrate.

16. The substrate according to claim 14, wherein the water-insoluble pattern is a tactile pattern.

17. A product comprising a substrate according to claim 14, wherein the product is a tool for bioassays, a microfluidic device, a lab-on-a-chip device, a paper-based analytical and/or diagnostic tool, a separation platform, a print medium, a packaging material, a data storage, a security document, a non-secure document, a decorative substrate, a drug, a tobacco product, a bottle, a garment, a container, a sporting good, a toy, a game, a mobile phone, a CD, a DVD, a blue ray disk, a machine, a tool, a car part, a sticker, a label, a tag, a poster, a passport, a driving licence, a bank card, a credit card, a bond, a ticket, a postage stamp, a tax stamp, a banknote, a certificate, a brand authentication tag, a business card, a greeting card, a braille document, a tactile document, or a wall paper.

18. A tactile application, a braille application, a printing application, an analytical application, a diagnostic application, a bioassay, a chemical application, an electrical application, a security device, an overt or covert security element, a brand protection, a micro lettering application, a micro imaging application, a decorative application, an artistic application, a visual application, or a packaging application, comprising a substrate comprising a water-insoluble pattern according to claim 14.

19. The method according to claim 2, wherein the treatment composition A and the treatment composition B are provided in liquid form.

20. The method according to claim 8, wherein the deliquescent salt of composition A is selected from the group consisting of chlorates, sulphates, halides, nitrates, carboxylates, and mixtures and hydrates thereof.

21. The method according to claim 8, wherein the deliquescent salt of composition A is selected from the group consisting of zinc iodide, manganese chloride, calcium chlorate, cobalt iodide, copper chlorate, manganese sulphate, stannic sulphate, magnesium chloride, calcium chloride, iron chloride, copper chloride, zinc chloride, aluminium chloride, magnesium bromide, calcium bromide, iron bromide, copper bromide, zinc bromide, aluminium bromide, magnesium iodide, calcium iodide, magnesium nitrate, calcium nitrate, iron nitrate, copper nitrate, silver nitrate, zinc nitrate, aluminium nitrate, magnesium acetate, calcium acetate, iron acetate, copper acetate, zinc acetate, aluminium acetate and mixtures and hydrates thereof.

22. The method according to claim 9, wherein the amount of the deliquescent salt is selected from the group consisting of 1 wt. % to 80 wt. %, 3 wt. % to 60 wt. % and 10 wt. % to 50 wt. %.

23. The method according to claim 1, wherein the acid or the salt thereof in the treatment composition B is selected from the group consisting of phosphoric acid, oxalic acid, tartaric acid and mixtures thereof.

24. The method according to claim 10, wherein the acid or the salt thereof in the treatment composition B is present in an amount selected from the group consisting of 1 wt.-% to 80 wt.-%, 3 wt.-% to 60 wt.-% and 10 wt.-% to 50 wt.-%.

25. The method according to claim 11, wherein the substrate is selected from the group consisting of paper, cardboard, containerboard and plastic.

26. The method according to claim 12, wherein the treatment composition A and/or the treatment composition B is/are deposited by inkjet printing or spray coating.

27. The substrate according to claim 16, wherein the water-insoluble pattern is a braille marking.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a comparative SEM image of substrate 1 only treated with treatment composition A. No formation of a water-insoluble pattern is detected on the substrate.

(2) FIG. 2 shows a comparative SEM image of substrate 1 only treated with treatment composition B. No formation of a water-insoluble pattern is detected on the substrate.

(3) FIG. 3 shows a SEM image with high order of magnitude of substrate 1 treated first with treatment composition B followed by treatment composition A. Calcium phosphate salt pigments of the water-insoluble pattern are visible on and between the fibres of the substrate.

(4) FIG. 4 shows a SEM image with low order of magnitude of substrate 1 treated first with treatment composition B followed by treatment composition A. The water-insoluble pattern on the left surface region of the substrate appears brighter than the untreated right surface region of the substrate.

(5) FIG. 5 shows a SEM image of a cross section of substrate 1 treated first with treatment composition B followed by treatment composition A. The water-insoluble pattern on the left surface region of the substrate appears brighter than the untreated right surface region.

(6) FIG. 6 shows a SEM image of substrate 1 treated first with treatment composition A followed by treatment composition B. Calcium phosphate salt pigments of the water-insoluble pattern are visible on the fibres of the substrate.

(7) FIG. 7 shows a SEM image of substrate 2 treated first with treatment composition A followed by treatment composition B. Calcium phosphate salt pigments of the water-insoluble pattern are visible on and within the substrate.

(8) FIG. 8 shows a digital camera image of a treated substrate 2 taken from a top view under ambient light conditions. The substrate was treated first with treatment composition A followed by treatment composition B. The water-insoluble pattern formed on the substrate in the form of a logo (mozaiq) is almost invisible.

(9) FIG. 9 shows a digital camera image of a treated substrate 2 taken from a top view with side light illumination at an angle of 20° relative to the surface of the substrate. The substrate was treated first with treatment composition A followed by treatment composition B. The water-insoluble pattern formed on the substrate in the form of a logo (mozaiq) is visible.

(10) FIG. 10 shows a digital camera image of a treated substrate 2 taken from a side view under ambient light conditions. The substrate was treated on different surface regions in the form of squares 1 to 6. The surface regions of square 1 to 4 were first treated with treatment composition A followed by different treatment compositions B. The surface region of square 5 was only treated with treatment composition A. The surface region of square 6 was only treated with treatment composition B. The water-insoluble pattern in square 1 to 4 are visible.

(11) FIG. 11 shows XRF mapping for iron of squares 1 and 2 of example 7 with fluorescence in square 1.

(12) FIG. 12 shows XRF mapping for zinc of squares 3 and 4 of example 7 with fluorescence in square 3.

(13) FIG. 13 shows a SEM image of substrate 1 treated first with treatment composition D followed by treatment composition C. Calcium sulphate salt pigments of the water-insoluble pattern are visible on and between the fibres of the substrate.

(14) FIG. 14 shows a SEM image with high order of magnitude of substrate 1 treated first with treatment composition D followed by treatment composition C. Calcium sulphate salt pigments of the water-insoluble pattern are visible on and between the fibres of the substrate.

(15) FIG. 15 shows a SEM image of substrate 1 treated first with treatment composition C followed by treatment composition D. Calcium sulphate salt pigments of the water-insoluble pattern are visible on the fibres of the substrate.

(16) FIG. 16 shows a SEM image with high order of magnitude of substrate 1 treated first with treatment composition C followed by treatment composition D. Calcium sulphate salt pigments of the water-insoluble pattern are visible on the fibres of the substrate.

EXAMPLES

(17) In the following, measurement methods implemented in the examples are described.

(18) 1. Methods

(19) Digital Photographs and Illumination

(20) Images of the prepared samples were recorded with an EOS 600D digital camera equipped with a Canon Macro lens, EF-S 60 mm, 1:2.8 USM (Canon Japan).

(21) For illumination a RB 5055 HF Lighting Unit (Kaiser Fototechnik GmbH & Co. KG, Germany) was used. The prepared samples were placed in the centre of the mid table of the lighting unit and were illuminated with one of the two lamps, wherein the distance between the substrates and the centre of the lamp was about 50 cm.

(22) Scanning Electron Microscope (SEM) Micrographs

(23) The prepared samples were examined by a Sigma VP field emission scanning electron microscope (Carl Zeiss AG, Germany) and a variable pressure secondary electron detector (VPSE) with a chamber pressure of about 50 Pa.

(24) X-Ray Diffraction (XRD) Analysis

(25) The prepared samples were analysed with a Bruker D8 Advance powder diffractometer obeying Bragg's law. This diffractometer consisted of a 2.2 kW X-ray tube, a sample holder, a ϑ-ϑ goniometer, and a VANTEC-1 detector. Nickel-filtered Cu Kα radiation was employed in all experiments. The profiles were chart recorded automatically using a scan speed of 0.7° per minute in 2ϑ (XRD GV 7600). The resulting powder diffraction pattern was classified by mineral content using the DIFFRAC.sup.suite software packages EVA and SEARCH, based on reference patterns of the ICDD PDF 2 database (XRD LTM_7603).

(26) Quantitative analysis of the diffraction data, i.e. the determination of amounts of different phases in a multi-phase sample, has been performed using the DIFFRAC.sup.suite software package TOPAS (XRD LTM_7604). This involved modelling the full diffraction pattern (Rietveld approach) such that the calculated pattern(s) duplicated the experimental one.

(27) Semi-Quantitative (SQ) calculations to estimate the rough mineral concentrations were carried out with the DIFFRAC.sup.suite software package EVA. The semi-quantitative analysis was performed considering the patterns relative heights and I/I.sub.cor values (I/I.sub.cor: ratio between the intensities of the strongest line in the compound of interest and the strongest line of corundum, both measured from a scan made of a 50-50 (equal concentration) by weight mixture).

(28) Energy-Dispersive X-Ray (EDS) Analysis

(29) The prepared samples were examined by a Sigma VP field emission scanning electron microscope (Carl Zeiss AG, Germany). The backscattered electron images were recorded in COMPO-Mode with a chamber pressure of about 50 Pa in order to visualize differences in the chemical composition of the sample. The heavier the atomic weight of the elements present, the brighter the particle appears in the image.

(30) The energy-dispersive X-ray images were recorded with an Oxford X-Max SDD-detector (Silicon Drift Detector) 50 mm.sup.2 (Oxford Instruments PLC, United Kingdom) and chamber pressure about 40-90 Pa (40-60 Pa for surfaces/approx. 90 Pa for cross-sections). Dot-mappings and EDS-analysis were taken with the energy dispersive x-ray detector (EDS). The EDS-detector determines the chemical elements of a sample and can show the position of the elements in the sample.

(31) X-Ray Fluorescence (XRF)

(32) The XRF measurement was made with a Hitachi EA6000VX machine, with the following settings:

(33) Voltage: 50 kV; Current: 1 000 μA; Filter: OFF; Collimator: 0.2×2 mm.sup.2; Scan Size: 27.720, 13.440 mm; Image Size: 462×224 pixel; Pixel Size: 60 μm/pixel; Time per pixel: 10.00 ms.

(34) 2. Materials

(35) 2.1. Substrates

(36) Substrate 1

(37) 60 g (dry) pulp (100% eucalyptus 30° SR) were diluted in 10 dm.sup.3 tap water. The suspension was stirred for 30 minutes. Subsequently, 0.06% (based on dry weight) of a polyacrylamide derivate (Percol® 1540, commercially available from BASF, Germany) was added as a retention aid and sheets of 80 g/m.sup.2 were formed using the Rapid-Kothen hand sheet former. Each sheet was dried using the Rapid-Kothen drier.

(38) Substrate 2

(39) Cellulose pulp based, uncoated surface-glued, security paper containing a watermark, slightly yellowish, basis weight 130 g/m.sup.2, containing minor amounts of calcium carbonate filler.

(40) 2.2. Treatment Compositions

(41) Treatment Composition a

(42) 48.5 wt.-% calcium chloride, 9.9 wt.-% ethanol, and 41.6 wt.-% water (wt.-% values are based on the total weight of the treatment composition A).

(43) Treatment Composition B

(44) 41 wt.-% phosphoric acid, 23 wt.-% ethanol, and 36 wt.-% water (wt.-% values are based on the total weight of the treatment composition B).

(45) Treatment Composition C

(46) 38 wt.-% calcium chloride, 9.4 wt.-% ethanol, and 52.6 wt.-% water (wt.-% values are based on the total weight of the treatment composition C).

(47) Treatment Composition D

(48) 4.9 wt.-% sulphuric acid, and 95.1 wt.-% water (wt.-% values are based on the total weight of the treatment composition D).

3. Examples

3.1. Examples 1 to 4

(49) Examples 1 to 4 were carried out on substrate 1 with a contact angle dispenser (Dataphysics OCA 50, DataPhysics Instruments GmbH, Germany) with 0.5 μl droplets in a line with partial overlapping. The centre of applied droplets was about 1-2 mm over a distance of about 1 cm. The prepared samples were examined by SEM imaging.

Example 1 (Comparative)

(50) Substrate 1 was treated with treatment composition A. No formation of a water-insoluble pattern was detected by SEM imaging (see FIG. 1).

Example 2 (Comparative)

(51) Substrate 1 was treated with treatment composition B. No formation of a water-insoluble pattern was detected by SEM imaging (see FIG. 2).

Example 3

(52) Substrate 1 was treated first with treatment composition B, followed by treatment composition A about 15 minutes later. Calcium phosphate salt pigments of the water-insoluble pattern were detected by SEM imaging on and between the fibres of the substrate (see FIG. 3). The salt formation took place on a defined surface region of the substrate (see FIG. 4) and within the substrate (see FIG. 5). In FIGS. 4 and 5 the whitish regions correspond to the formed water-insoluble pattern, while the dark regions correspond to untreated substrate areas.

Example 4

(53) Substrate 1 was treated first with treatment composition A, followed by treatment composition B about 15 minutes later. Calcium phosphate salt pigments of the water-insoluble pattern were detected by SEM imaging on the fibres of the substrate (see FIG. 6).

3.2. Examples 5 to 7

(54) Examples 5 to 7 were carried out on substrate 2 with an inkjet printer (Dimatix DMP 2831, Fujifilm Dimatix Inc., USA) with 10 pl droplet size at a drop spacing of 25 μm.

Example 5

(55) Substrate 2 was inkjet printed in form of a pre-defined pattern with treatment composition A, followed by treatment composition B about 15 minutes later. Calcium phosphate salt pigments of the water-insoluble pattern were detected by SEM imaging on and within the substrate (see FIG. 7).

Example 6

(56) Substrate 2 was inkjet printed in the form of a logo (mozaiq) with treatment composition A followed by treatment composition B about 15 minutes later. The water-insoluble pattern, i.e. the logo, was invisible to the naked eye from a top view on the substrate under ambient light conditions (see FIG. 8). However, the logo became visible to the naked eye from a top view when illuminated with side light at an angle of 20° relative to the surface of the substrate (see FIG. 9). The good visibility of the water-insoluble pattern in the latter case is due to different light scattering of the calcium phosphate pigments on and within the substrate.

Example 7

(57) Substrate 2 was inkjet printed in the form of 6 separate squares (surface area 1×1 cm.sup.2). In case of square 1 to 4, treatment composition A was deposited first followed by the corresponding treatment composition B about 15 minutes later. In case of squares 1 to 3 a tracer (iron chloride, aluminium chloride, zinc carbonate) was included. The composition of the printed squares is indicated in Table 1 below.

(58) The squares were treated with the following combination of treatment compositions:

(59) Square 1 was printed with treatment composition A, followed by printing with treatment composition B additionally comprising 1 wt.-% iron chloride, based on the total weight of treatment composition B.

(60) Square 2 was printed with treatment composition A, followed by printing with treatment composition B additionally comprising 1 wt.-% aluminium chloride, based on the total weight of treatment composition B.

(61) Square 3 was printed with treatment composition A, followed by printing with treatment composition B additionally comprising 5 wt.-% zinc carbonate based on the total weight of liquid composition B.

(62) Square 4 was printed with treatment composition A, followed by printing with treatment composition B.

(63) Square 5 was printed with treatment composition A only.

(64) Square 6 was printed with treatment composition B only.

(65) TABLE-US-00001 TABLE 1 Composition of the printed squares. Treatment Treatment Printed square composition B composition A Tracer 1 Phosphoric acid Calcium chloride Iron chloride 2 Phosphoric acid Calcium chloride Aluminium chloride 3 Phosphoric acid Calcium chloride Zinc carbonate 4 Phosphoric acid Calcium chloride — 5 (comparative) — Calcium chloride — 6 (comparative) Phosphoric acid — —

(66) Under ambient light conditions, the printed squares 1 to 4 were visible to the naked eye from a side view due to different light scattering of the calcium phosphate salt pigments of the water-insoluble pattern on and within the substrate (see FIG. 10).

(67) The printed squares were also examined by XRF and the results of the element mapping are compiled in Table 2 below.

(68) TABLE-US-00002 TABLE 2 Results of XRF measurements (+indicates the presence of an element). Square 5 Square 6 Element Square 1 Square 2 Square 3 Square 4 (comparative) (comparative) Phosphorus + + + + − + Calcium + + + + + − Chlorine + + + + + − Iron + − − − − − Zinc − − + − − −

(69) The XRF measurements confirmed the presence of phosphorus, calcium and chlorine on squares 1 to 4 prepared according to the present invention.

(70) Furthermore, the results of the XRF measurements confirmed that the iron tracer and the zinc tracer can be detected in the printed squares. A map of iron of squares 1 and 2 is shown in FIG. 11. While the iron tracer in square 1 was clearly detectable (see FIG. 11, left), square 2 does not show the presence of iron (see FIG. 12, right). A map of zinc of squares 3 and 4 is shown in FIG. 12. While the zinc tracer in square 3 was clearly detectable (see FIG. 12, left), square 4 does not show the presence of zinc (see FIG. 12, right).

3.3. Examples 8 and 9

(71) Examples 8 and 9 were carried out on substrate 1 with a contact angle dispenser (Dataphysics OCA 50, DataPhysics Instruments GmbH, Germany) with 0.5 μl droplets in a line with partial overlapping. The centre of applied droplets was about 1-2 mm over a distance of about 1 cm. The prepared samples were examined by SEM imaging.

Example 8

(72) Substrate 1 was treated first with treatment composition D, followed by treatment composition C about 15 minutes later. Calcium sulphate salt (gypsum) pigments of the water-insoluble pattern were detected by SEM imaging on and between the fibres of the substrate (see FIGS. 13 and 14).

Example 9

(73) Substrate 1 was treated first with treatment composition C, followed by treatment composition D about 15 minutes later. Calcium sulphate salt (gypsum) pigments of the water-insoluble pattern were detected by SEM imaging on and between the fibres of the substrate (see FIGS. 15 and 16).