Systems and methods for generating a permanent image and use of specific substances for generating a permanent image

Abstract

The invention relates to systems and a method for producing a permanent image using an image template comprising a first layer having at least one motif and a second hydrochromic layer arranged on the first layer, wherein the systems further comprise either a transparent liquid having a boiling point of at least 150 °C at 1000 hPa atmospheric pressure or a mixture, wherein the mixture comprises at least one solvent and at least one binder, wherein the binder is dissolved or dispersed in the solvent and the proportion of the binder, based on the total mass of the mixture, is at least 20% by mass.

Description

[0001] The present invention relates to systems and a method for producing a permanent image and to the use of a transparent liquid having a boiling point of at least 150 °C at 1000 hPa air pressure or a mixture containing a solvent and at least one binder for producing a permanent image.

[0002] So-called water-based coloring books for children have been available on the market for many years. A water-based coloring book is a coloring book in which images are created by applying water. The images created with water are initially invisible on the unused pages of the coloring book, but are covered by an opaque, usually white, matting hydrochromic layer that becomes transparent upon contact with water, revealing the image beneath the hydrochromic layer. The effect used in these coloring books is also known as the "wet reveal" effect, and hydrochromic inks can be purchased from companies such as "coates."

[0003] US 7,753,680 B2 describes a water-discoloring drawing toy designed so that a drawing produced by applying a writing instrument or applicator for water adhesion produces a multicolored image. The drawing toy comprises a substrate; many color-different and adjacent non-discoloring images arranged on the substrate such that in the part with the non-discoloring images, at least two color tones per 100 cm 2can be visually recognized. The drawing toy further comprises a porous layer for preventing the non-staining images from being seen in the normal state, wherein the porous layer is disposed over the non-staining images and comprises a binder resin and a low-refractive-index pigment fixed therein in a dispersed state, wherein the porous layer has a difference in transparency between a liquid-impregnated and an unstained state.

[0004] JP 2005-15777 A provides a liquid composition for a color-changing body. The color-changing body is obtained by forming a porous layer, wherein the porous layer is obtained by incorporating a pigment with a low refractive index into a binder resin and applying the pigment dispersed in the binder resin to a support. The porous layer changes color by transforming into a transparent or opaque state upon absorption of liquid. The liquid composition is obtained by dispersing a solid material with a refractive index of 1.3 to 1.8 in a medium. A color-changing body kit comprises the color-changing body and the liquid composition.

[0005] WO 2016 / 039222 A1 teaches a color-changing playhouse that a child can enter and play with, forming pictures or words with water without losing interest even after extended use. The playhouse returns to its original state through evaporation and drying of the applied water. The color-changing toyhouse is formed from color-changing cardboard. The cardboard consists of a core and a liner. A waterproof layer is disposed on the liner surface of the cardboard. A porous layer is disposed on the waterproof layer. The porous layer has different light transmittances in an adsorption state and a non-adsorption state. A pigment with a low refractive index is bonded to a binder resin in a dispersed state.Also described is a color-changing playhouse set, which consists of the color-changing playhouse and a water applicator.

[0006] A disadvantage of commercially available systems with hydrochromic layers, such as the coloring books mentioned above, is that the effect of making the image or motif beneath the hydrochromic layer visible is temporary and only lasts until the applied water has evaporated. While this allows the coloring book to be reused, it cannot permanently create the image underlying the system.

[0007] Based on this prior art, it is an object of the present invention to provide systems and methods for producing a permanent image. Furthermore, it is an object of the present invention to provide the use of a transparent liquid with a boiling point of at least 150°C at 1000 hPa atmospheric pressure and also the use of a mixture containing a solvent and at least one binder.

[0008] The objects are achieved by the features of the independent claims. The dependent claims contain advantageous developments and refinements of the invention.

[0009] According to a first aspect of the present invention, the object of creating a permanent image is achieved by a first system comprising an image template and a transparent liquid. The image template comprises a first layer and a second layer and may comprise further layers. The first layer is the layer that produces the final image. It comprises at least one motif, which can be of any desired shape, color, size, and design. Two or more motifs can also be combined in the first layer.

[0010] The second layer, which is in the form of a second hydrochromic layer, is arranged on top of the first layer. The second layer can partially or even completely cover the first layer. It acts as a matting layer, which is particularly opaque and thus has a whitish color, thus covering the motif(s) of the first underlying layer, so that the motif(s) are not visible in this state.

[0011] For the purposes of the present invention, a hydrochromic layer is understood to be a layer that changes its appearance from opaque to transparent upon contact with water. The second hydrochromic layer is formed, in particular, from a hydrochromic ink that is applied to the first layer and dried. Hydrochromic inks are commercially available, for example under the trade name PF 70 / 32 from Coates. The second hydrochromic layer can also comprise motifs. However, this is not mandatory. To encourage the application of the transparent liquids, motifs are preferably also present in the second hydrochromic layer to promote the application of the transparent liquid in specific areas of the second hydrochromic layer.

[0012] However, unlike conventional water-based coloring books, which use water, the first system according to the invention comprises a transparent liquid with a boiling point of at least 150 °C at 1000 hPa atmospheric pressure. The higher the boiling point of the transparent liquid, the more permanent the image is.

[0013] A transparent liquid within the meaning of the present invention is understood not only to mean a liquid with a boiling point of at least 150°C at 1000 hPa air pressure, but also a liquid with sufficiently high transparency. To this end, the liquid has, in particular, a transmittance of 0.02% to less than 100%. The transmittance refers to the quotient of outgoing light intensity / incident light intensity and is measured photometrically using light with a wavelength between 400 and 800 nm, for example, at 550 nm. The higher the transmittance, the greater the transparency of the liquid and the clearer the motif of the first layer appears beneath the then transparent second layer.

[0014] If the transparent liquid described above is applied to the surface of the second hydrochromic layer, the hydrochromic layer becomes transparent, losing its opacity or inherent color and thus also its matting effect, allowing the motif(s) of the first layer beneath the hydrochromic layer to shine through. Because the transparent liquid has a boiling point of at least 150°C, it evaporates more slowly than water, so the transparency of the second layer is permanently maintained, and thus the motif(s) of the first layer are also permanently visible.

[0015] The boiling point of the transparent liquid is not specifically limited and can be as high as desired, as long as it is at least 150 °C, measured at an air pressure of 1000 hPa.

[0016] There are no other restrictions on the transparent liquid. However, the transparent liquid should not contain any substances that could dissolve or disperse the image in the first layer, as otherwise the image will "bleed" upon contact with the transparent liquid, making it harder to see.

[0017] The first system according to the invention is characterized by a simple and efficient composition by which a prefabricated image comprising at least one motif contained in the first layer can be made permanently visible.

[0018] According to the invention, a second system for generating a permanent image is also described.

[0019] Like the first system, the second system also comprises an image template, which, like the image template, can be designed in the first system. Thus, with regard to the image template and the effects to be achieved by the second system, reference is made to the first system described above. The second system differs from the first system in that no transparent liquid as disclosed above is used to make the motif(s) of the first layer permanently visible under the second hydrochromic layer, but rather a mixture is provided which comprises at least one solvent and at least one binder. The proportion of the binder, based on the total mass of the mixture, is at least 20% by mass, and the binder is dissolved or dispersed in the solvent. It is essential that the mixture forms a transparent film after the evaporation of any volatile substances it may contain.For this purpose, the binder has a minimum film-forming temperature below room temperature (25 °C).

[0020] In other words, the mixture or the resulting film is characterized by a high degree of transparency, which, as with the transparent liquid described above, ranges from 0.02% to less than 100%. This transparency is maintained at least in the "dried" state of the mixture, in which the binder forms a film.

[0021] Without being bound by theory, after drying, the mixture either lies in the form of a dried transparent layer on the second hydrochromic layer, or the mixture is absorbed by the hydrochromic layer, and the dried transparent film fills the spaces between the opaque particles contained in the second hydrochromic layer, thus resulting in a permanent transparency of the hydrochromic layer. The transparency is measured as described above for the transparent liquid.

[0022] The solvent in the mixture is not specifically limited and can, for example, be selected from water, alcohols, esters, and any mixtures thereof, and the like. Preferably, the solvent, if not water, is a water-soluble or water-miscible solvent. For the purposes of the present invention, a water-soluble or water-miscible solvent is understood to mean a solvent that has a solubility in water of more than 30 vol.% at 25°C and does not form a separate phase under these conditions.

[0023] The binder is also not specifically restricted, and any binder, especially polymeric binders such as natural or synthetic polymers, can be used. Examples include celluloses, pectins, xanthan gum or other gums, polyurethanes, polyacrylates, polyolefins, and epoxy resins, which can be present individually or in mixtures with other polymers.

[0024] The effect of changing the opacity of the second hydrochromic layer to a transparency of the second hydrochromic layer by applying water to the second hydrochromic layer is known. What has not been recognized is that permanent transparency, and thus a permanent translucence of the motif(s) of the first layer through the transparent second hydrochromic layer, can be achieved by using a solvent in the form of a mixture with at least one binder.

[0025] Without being bound by theory, it is assumed that by using the mixture, the refractive index is adjusted to the refractive index of the first layer, so that the second layer changes its appearance from opaque to transparent. In other words, it is assumed that the transparent liquid or the solvent / binder mixture fills the spaces between the individual particles of the second hydrochromic layer, thus reducing light scattering in the second hydrochromic layer. Consequently, the opacity decreases, and the second hydrochromic layer thus becomes more transparent. This then leads to the motif of the first layer shining through.

[0026] The permanent transparency, which is also responsible for creating the permanent image, results from the low (or virtually nonexistent) evaporation rate of the binder. To achieve this, the binder content, based on the total mass of the mixture, is at least 20% by mass, and in particular, it is in the range of 30 to 70% by mass, and especially 35 to 65% by mass, to achieve good flowability of the mixture so that it spreads evenly over the second hydrochromic layer.

[0027] The second system can also produce a permanently visible image using a hydrochromic layer.

[0028] Unless otherwise stated in the following statements, the advantages, beneficial effects, further developments and configurations apply to both the first system and the second system.

[0029] Acrylic resins, alkyd resins, polyurethane resins and polyester resins are readily miscible or dispersible in water and are also characterized by very good adhesive properties and are therefore preferably used in the mixture of the second system.

[0030] In order to create a permanently visible image, the first layer advantageously comprises a plastic-based medium, a fiber-based medium or a textile-based medium. A plastic-based medium is understood in particular to be media that are in the form of a more or less thick layer or film. This can be, for example, packaging films but also items of clothing and parts thereof. A fiber-based medium is understood to be media that comprise fibers of any kind. The fibers can be synthetic, natural or nature-identical. Particularly common fiber-based media are fleece, paper and cardboard, with paper and cardboard comprising in particular cellulose fibers. Textile media is understood in particular to be woven, braided, warp-knitted or knitted media that are used in particular for items of clothing, furniture and home accessories.The materials used for this purpose are not limited in detail and can also be synthetic, natural or nature-identical.

[0031] The motif(s) of the first layer can preferably be applied to the plastic-based medium described above, the fiber-based medium, or the textile-based medium. Printing processes such as offset printing are particularly suitable for this. These printing processes produce the motifs with particular accuracy and long-lasting stability.

[0032] As already stated above, the design of the motif(s) of the first layer is essentially unlimited. Preferably, the motif(s) are formed in one or more colors. This allows the motif to stand out particularly well from the medium of the first layer and also from the second layer, which is formed in particular with white or opaque color.

[0033] According to a further advantageous development, the second hydrochromic layer is formed from a dried hydrochromic ink applied to the first layer. In other words, a hydrochromic ink known in the prior art and commercially available can be used to produce the second hydrochromic layer, which forms the second hydrochromic layer after drying off any solvents. "Drying" here refers not only to the evaporation of solvents, but also to curing, such as curing with UV rays. Any method of fixing the second hydrochromic layer to the first layer is suitable.

[0034] Preferably, a hydrochromic ink usable for the present invention comprises at least one solvent, at least one binder, and at least one pigment for forming the second hydrochromic layer, wherein the binder can be selected from acrylic resins, alkyd resins, polyurethane resins, and polyester resins, and wherein the pigment is selected from sodium aluminum silicates, amorphous silicas, clay, gypsum, aluminum oxides, talc (magnesium silicate), and metal carbonates. Preferably, no further pigments are included to improve transparency upon contact with the transparent liquid or mixture. Furthermore, the binder is advantageously of the same type as the binder used in the mixture, since in this way the refractive indices of the second layer and the mixture can be particularly well matched, and the transparency of the second hydrochromic layer can be improved.Pigment particle sizes range from 1 to 35 µm. The particle size refers to the D50 value, which is measured in suspension using dynamic light scattering.

[0035] The hydrochromic layer is particularly advantageous when applied by a screen printing process, since the screen printing process allows a suitable layer thickness of the hydrochromic layer to be adjusted particularly well.

[0036] In order to expose the motif(s) of the first layer for a particularly long time and thus permanently through the transparency of the second layer, the transparent liquid preferably has a vapor pressure of less than 1000 hPa at 20°C.

[0037] Transparent liquids selected from vegetable oils, synthetic oils, petroleum-based oils, glycols, alcohols, glycol ethers, glycol esters, silicone oils, and any mixtures thereof are particularly suitable due to their easy availability, high boiling point, low vapor pressure, and ease of use. Vegetable oils are particularly preferred due to their sustainability and environmental friendliness.

[0038] For the reasons stated above, the transparent liquid is further preferably selected from sunflower oil, rapeseed oil, linseed oil, walnut oil, olive oil, ester oils, such as in particular isopropyl myristate and isopropyl palmitate, paraffin oils, glycerin, polydimethylsiloxane and any mixtures thereof.

[0039] In order to better distribute the transparent liquid or mixture over the second hydrochromic layer, the systems according to the invention can further comprise an application device. To improve the spreadability of the transparent liquid or mixture, the transparent liquid or mixture is preferably provided in a writing device or a painting device. The writing device or painting device can thus be part of the system. For this purpose, the writing device or painting device comprises, in particular, a reservoir which contains the transparent liquid or mixture and from which the transparent liquid or mixture can be conveyed for application. The reservoir can simply be a storage container in which the transparent liquid is present in unbound form, or it can also be a fiber reservoir.Suitable application devices include markers with a fiber reservoir and tip, "free ink" markers with a free liquid reservoir and a valve system for dispensing, or markers with free ink in a reservoir with an associated compensation element for pressure and heat equalization. Alternatively, the transparent liquid or mixture can also be applied with brushes, rollers, rags, sponges, or similar devices.

[0040] To particularly effectively prevent the transparent liquid or mixture from flowing off or spreading and thus promote the permanence of the generated image, the image template preferably comprises a barrier layer beneath the first layer or between the first layer and the second hydrochromic layer. For the purposes of the present invention, a barrier layer is understood to mean a layer characterized by low porosity and low absorption capacity for the transparent liquid or mixture, so that the transparent liquid or mixture is not absorbed by the barrier layer and its polarity is, in particular, contrary to the polarity of the transparent liquid or mixture.

[0041] The barrier layer can be made of a transparent material, such as polypropylene, PVC, polyester, and the like. The barrier layer prevents the transparent liquid or mixture from being absorbed by the substrate of the image, which could compromise the permanence of the image. The barrier layer does not necessarily have to be a film. It is also conceivable to place a barrier layer above or below the image using printing techniques.

[0042] A further aspect of the invention relates to a method for producing a permanent image. The method comprises a step of forming an at least two-layered image template comprising a first layer having at least one motif and further comprising a second hydrochromic layer arranged on the first layer.

[0043] The second hydrochromic layer can be created using a hydrochromic ink. The hydrochromic layer can also be applied to a transparent film, which then acts like the barrier layer described above. A second hydrochromic layer thus formed can then be bonded to the first layer, for example, using an adhesive.

[0044] Then, a transparent liquid having a boiling point of at least 150 °C, measured at 1000 hPa air pressure, or a mixture containing at least one solvent and at least one binder dissolved or dispersed in the solvent, and wherein a proportion of binder, based on the total mass of the mixture, is at least 20 mass%, is applied to the second hydrochromic layer.

[0045] In the areas where the transparent liquid or mixture is applied to the second layer, the opacity of the second layer changes to transparent, so that the motif(s) of the first layer lying beneath the second layer and covered by the second layer become visible in these areas due to the transparency of the second layer.

[0046] The method is easy to apply without requiring significant technical effort and enables the creative creation of a permanent image that is initially invisible. With regard to the advantageous embodiments of the method, reference is also made to the systems according to the invention. The advantageous developments of the method according to the invention and the systems according to the invention are mutually applicable.

[0047] A further aspect of the invention relates to the use of a transparent liquid with a boiling point of at least 150°C, measured at 1000 hPa atmospheric pressure, or of a mixture containing at least one solvent and at least one binder, wherein the binder is dissolved or dispersed in the solvent and a binder content, based on the total mass of the mixture, is at least 20% by mass. The transparent liquid or the mixture is used with the aim of producing a permanent image from an image template comprising a first layer having at least one motif and a second hydrochromic layer arranged on the first layer. The image can be produced by the method according to the invention disclosed above and thus by applying the transparent liquid or the mixture.

[0048] The advantages, advantageous effects and further developments described for the first and second systems according to the invention, the method according to the invention and the use according to the invention are each mutually applicable. - Example -

[0049] Below, a recipe is given for components for forming a first layer according to the invention and for components for forming a second layer according to the invention. First layer:

[0050] The first layer (motif-bearing) is a cardboard surface (white) printed with corresponding motifs using the following ingredients: - 10 mass% color pigment (e.g. HelioBeit LW305, HelioBeit-LW 905 from Helio Beit or others) - 30% by weight polymer dispersion Esacote AC 200 (from Lamberti surface treatment) - 0.3 mass% defoamer BYK-019 (from BYK) - 2 mass% wetting agent DisperBYK-168 (from BYK) - 0-4 mass% RheoBYK-425 (to adjust the rheology properties; from BYK) - Rest: Water Second layer: - 50 mass% Bayhydrol UV 2720 / 1 (from Covestro AG); aqueous UV varnish - 15% by mass Dorkafill H (kaolin; from Dorfner) - 15% by mass MinTalc 97-05 (talc; from Nobelmin) - 3 mass% Irgacure 500 (photoinitiator; from BASF) - 3 mass% Byk 348 (wetting aid; from BYK) - 0-3 mass% rheology additive to adjust the appropriate viscosity (see above) - Rest: Water

[0051] The components of the second layer can optionally be mixed in a ratio of 10:1 (based on mass%) with polyisocyanate (e.g. Bayhydur 305) to obtain a 2-component system with increased abrasion resistance.

[0052] To illustrate the present invention, reference is made to the following description and the figures. Fig. 1 shows an excerpt from a conventional water coloring book, which can be purchased. Fig. 1A and Fig. 2A shows the initial state.

[0053] Shown in each case is the same two-layer image template, comprising a first layer and an overlying second hydrochromic layer. The first layer contains motifs concealed beneath the second hydrochromic layer. The first layer and the second hydrochromic layer are formed using the components listed above for producing the first and second layers. The second hydrochromic layer also contains motifs intended to encourage the user to apply water. The second hydrochromic layer is characterized by a certain opacity or color, which conceals the motifs of the first layer.

[0054] Fig. 1B and Fig. 2B each show the motifs of the first layer. According to a conventional process, the image template from Fig. 1A water was applied. This changed the color / opacity of the second hydrochromic layer to transparent, and the motifs of the first layer beneath the second hydrochromic layer became visible.

[0055] The same effect was observed in Fig. 2B, but using a transparent liquid with a boiling point of at least 150 °C at 1000 hPa atmospheric pressure. Paraffin oil, which had a boiling point of at least 150 °C, was applied as the transparent liquid.

[0056] The difference between the conventional system or procedure according to Fig. 1A to C and the system or method according to the invention according to Fig. 2A to C is shown when looking at Fig. 1C compared to Fig. 2C. Fig. 1C and Fig. 2C were recorded after 20 min of drying after application of water or paraffin oil. Fig. 1C shows the state again Fig. 1A, i.e. the motifs of the second hydrochromic layer, which are colored or opaque over the motifs of the now invisible first layer.

[0057] In comparison, Fig. 2C still contains the same motifs from the first layer Fig. 2B. The transparency of the second hydrochromic layer was maintained because the paraffin oil did not dry out and evaporate due to its high boiling point of at least 150 °C.

[0058] For the sake of completeness, Fig. 2D shows the state of the system according to the invention 96 hours after application of paraffin oil to the second hydrochromic layer. The motifs of the first layer are still visible. This means that, according to the invention, the image from the motifs of the first layer is permanently visible, while by applying water, after the water has dried off, the opacity or color of the second hydrochromic layer in the example of Fig. 1A to 1C.

Claims

[1] System for generating a permanent image comprising: - an image template comprising: - a first layer comprising at least one motif and - a second hydrochromic layer arranged on the first layer and - a transparent liquid with a boiling point of more than 150 °C at 1000 hPa atmospheric pressure. [2] System for generating a permanent image comprising: - an image template comprising: - a first layer comprising at least one motif and - a second hydrochromic layer arranged on the first layer and - a mixture containing at least one solvent and at least one binder, wherein the binder is dissolved or dispersed in the solvent and a proportion of the binder, based on the total mass of the mixture, is at least 20% by mass. [3] The system of claim 2, wherein the binder is selected from acrylic resins, alkyd resins, polyurethane resins and polyester resins. [4] The system of any one of claims 1 to 3, wherein the first layer comprises a plastic-based medium, a fiber-based medium, or a textile-based medium. [5] System according to claim 4, wherein the motif is applied, in particular printed, to the plastic-based medium, the fiber-based medium or the textile-based medium. [6] System according to one of the preceding claims, wherein the motif is formed in one or more colors. [7] A system according to any one of the preceding claims, wherein the second hydrochromic layer is formed from a dried hydrochromic ink applied to the first layer. [8] System according to claim 7, wherein the hydrochromic ink comprises at least one solvent, at least one binder and at least one pigment, wherein the binder is in particular selected from acrylic resins, alkyd resins, polyurethane resins and polyester resins and wherein the pigment is selected from sodium aluminum silicates, amorphous silicas, clay, gypsum, aluminum oxides, talc and metal carbonates. [9] A system according to any one of the preceding claims, wherein the hydrochromic layer is a layer applied by a screen printing process. [10] System according to any one of claims 1 and 4 to 9, wherein the transparent liquid has a vapor pressure of less than 1000 hPa at 20°C. [11] System according to any one of claims 1 and 4 to 10, wherein the transparent liquid is selected from vegetable oils, synthetic oils, petroleum-based oils, glycols, glycol ethers, glycol esters, alcohols, silicone oils and any mixtures thereof. [12] System according to one of claims 1 and 4 to 11, wherein the transparent liquid is selected from sunflower oil, rapeseed oil, linseed oil, walnut oil, olive oil, ester oils, such as in particular isopropyl myristate and isopropyl palmitate, paraffin oils, glycerin, polydimethylsiloxane and any mixtures thereof. [13] A system according to any one of the preceding claims, wherein the transparent liquid or mixture is provided in a writing implement or a painting implement. [14] A system according to any preceding claim, wherein the image template comprises a barrier layer beneath the first layer or between the first layer and the second hydrochromic layer. [15] A method for producing a permanent image comprising the steps of: - Forming an image template with at least two layers comprising: - a first layer comprising at least one motif and - a second hydrochromic layer arranged on the first layer and - applying a transparent liquid having a boiling point of at least 150 °C at 1000 hPa air pressure or a mixture containing a solvent and at least one binder, wherein the binder is dissolved or dispersed in the solvent and a proportion of the binder, based on the total mass of the mixture, is at least 20% by mass, to the second hydrochromic layer. [16] Use of a transparent liquid having a boiling point of at least 150 °C at 1000 hPa air pressure or of a mixture containing a solvent and at least one binder, wherein the binder is dissolved or dispersed in the solvent and a proportion of the binder, based on the total mass of the mixture, is at least 20% by mass for producing a permanent image from an image template which comprises a first layer having at least one motif and a second hydrochromic layer arranged on the first layer.

Images