decorative surface

The subject of the invention is a method for producing a decorative surface on a carrier, which is in particular unprinted impregnated paper or unprinted non-impregnated paper. The invention also relates to a product comprising such a decorative surface.

The invention may by applied in the furniture, floor and textile industry for the production of decorative papers and decorative foils, particularly used in the production of furniture boards, floor panels or for the production of decorative fabrics.

A characteristic feature of the surface obtained is a specific decorative pattern, reminiscent of the marble pattern, known from the traditional Ebru method. The means used to produce this solution determine how the unique decoration is created.

There is a known method of obtaining a marbled surface, derived from the traditional art of paper decoration called Ebru. The approach is to decorate the paper by applying to the paper the patterns created with the help of inks distributed with brushes and sticks on water thickened with a plant-derived agent. Paper decorated using this technique is also called Turkish paper or marbled paper. According to the assumptions of the method, inks containing bovine yellow are used, which are spread with horsehair brushes and sticks on water usually thickened with tragacanth gum. The first applied inks are darker ones and then lighter ones. A blank sheet of paper is applied to the pattern formed on the surface of thickened water and the pattern is transferred onto the paper. The invention GB2415439 describes a method in which the polysaccharide, carrageenan, is mixed with water in a flat vessel. Then, drops of antistatic agent diluted in distilled water, which is a photographic moisturising fluid, are placed on the surface of the carrageenan solution and then mixed to distribute evenly. Using a dropper, acrylic ink of one colour or several colours is placed on the surface in drops of ink on top of each other to form concentric coloured rings. Then the same antistatic is applied to the surface of the carrageenan solution, in a ink-free location, especially near the edge of the container. This causes irregular shrinkage of ink stains and then you need to collect excess antistatic from the surface with tissue paper before the ink begins to fall. This action causes the ink on the surface to crack significantly, creating a marbling effect in the form of distorted circular feathery or generally jagged shapes. Subsequent application and collection of the antistatic agent again causes cracking and distortion to achieve an even more feathery effect. After achieving the desired effect, the pattern is applied to the material using a known method.

All traditional methods and those aimed at obtaining a marbled pattern applied to paper or fabric or another type of material are based on a single dip of a small piece of paper or material. It is not possible to apply a reproducible effect to a larger area, especially continuously.

The subject of the invention was therefore to develop a method that allows the transfer of a marbled graphical patter, similar to that traditionally obtained by the Ebru method, onto the surface of paper fed continuously, especially from a roll.

The subject of the invention is the production of decorative surfaces assisted by a process using a number of technical means. In principle, the decoration is meant to resemble the designs known from Ebru art, but the method of its production is to be implemented in a continuous, repeatable manner in terms of the nature of the decoration and ensuring production efficiency.

The essence of the invention according to the method lies in the fact that a primer layer which is a mixture of water and at least an additive increasing the surface tension is applied on the carrier moving in the system of the coating machine in the form of a web unwound from the role of a carrier. At the same time, a certain thickness of this layer is determined and then drops of ink are applied to the wet surface of the carrier. When in contact with a moist surface characterised by high surface tension, these droplets create spots that expansively increase their surface area. The carrier web is continuously transferred to the drying tunnel and subjected to drying until the appropriate moisture content of the carrier is achieved.

In addition, it is preferred that the mixture contains pigment.

Preferably, the carrier is unprinted impregnated paper or unprinted non- impregnated paper, or a polymer film, especially a Biaxially Oriented Polypropylene (BOPP Film) or a textile fabric.

It is also advantageous if the moving speed of the carrier web is between 5 and 350 m/min, especially between 20 and 200 m/min.

It is also preferred that the surface tension enhancing agent is tragacanth gum and / or xanthan gum, and / or gellan gum, and / or native starch, and / or modified starch, especially acetylated starch, and / or a cellulose agent or cellulose derivative agent especially wallpaper glue.

It is also preferred if the mixture layer is applied to the coating machine using the Meyer Bar application system.

It is also advantageous if the mixture layer is applied by means of a three-roller smudging system in which the application roller applies a coating layer by contact with the carrier.

It is also advantageous if the mixture layer is applied by means of a pouring system.

It is also preferred that the thickness of the applied layer of the mixture of water and surface tension enhancing agent is from 5 ml/m ² to 200 ml/m ² .

It is also advantageous if the ink droplets are applied by sprayers located in the ink spray zone, with pressure spray nozzles at a pressure of at least 0.1 MPa, in particular a pressure of 0.15 MPa to 0.6 MPa.

It is also preferred that the distance of the moving carrier web from the nozzles in the ink spray zone or dripper is from 0.5 to 150 cm, especially when the distance from the vertically moving web is 20 to 120 cm. It is also advantageous if the ink droplets are applied by a dripper located above the horizontally moving carrier web.

It is also advantageous if the ink droplets are applied using spray nozzles in the ink spray zone and / or the dripper system, which are digitally programmed and / or electronically controlled.

It is also preferred if the ink of at least one colour is applied.

It is also preferred that the time from the application of the ink droplet to the moist surface of the carrier until the web enters the drying channel is from 0.5 to 30 seconds.

In turn, the essence of the invention of the product is that it contains at least a carrier covered with a multilayer surface obtained according to the essence of the invention being a method and consisting of a primer layer formed from solid particles of at least a surface tension increasing additive that remained on the carrier after evaporation of water from the mixture layer at the drying stage and from the dried ink layer, resulting from the application of ink droplets on the wet mixture layer.

In addition, it is preferred that the primer layer is complemented by pigment particles dissolved in the mixture remaining on the carrier after the water has evaporated from the mixture layer.

Preferably, the carrier is impregnated paper or non-impregnated paper, or a polymer film, especially a Biaxially Oriented Polypropylene (BOPP Film) or a textile fabric.

It is also preferred that the primer layer is formed from solid particles of tragacanth gum and / or xanthan gum, and / or gellan gum, and / or native starch and / or modified starch, especially acetylated starch, and / or a cellulose based agent or cellulose derivative agent, especially wallpaper glue.

In the description, the word "mixture" will be used to describe water mixed with an appropriate proportion of the surface tension enhancing agent and its properties will cause an increased surface tension at the interface between the carrier - the mixture and at the interface between the ink and the mixture.

The ink used to accomplish the invention is an aqueous printing ink. After applying a certain amount of aqueous ink, the carrier takes on a decorative form. The appearance of this decoration depends primarily on the number of spray nozzles used, but many other factors also have an effect. It has been experimentally proven what determines the final result of the decorative layer.

One of the most important components that can be changed during the process is the viscosity of the mixture coating the carrier. Choosing the right amount of the surface tension enhancing agent affects the final result, or more precisely the shape and size of the marble pattern.

Increased surface tension at the interface of the mixture - droplets of ink causes the applied droplet of ink to constantly change their shape and expand creating a unique pattern until it is cured. Thus, it can be concluded that a different decoration will be created during a shorter time of the ink on the carrier web until it is cured, and a different one for a longer time.

In the present invention, the main factor affecting the pattern is the viscosity of both the ink and the mixture, as well as the amount of the mixture applied, i.e. the thickness of its layer. We get a different result with higher viscosity of both media and a different result with lower viscosity.

Another parameter that determines the final appearance of the decor is the amount of ink applied to the carrier web. Adjusting the feed speed of the carrier web changes the amount of ink applied to the carrier. Slower web travel results in more ink in a specific place on the media, and faster travel - less ink. A similar result can be achieved with a constant web feed speed and a change in the pressure of ink flow at the nozzles. The higher the pressure, the greater the amount of ink applied to the carrier web.

A special case of obtaining a peculiar decoration is the use of a pigment additive in the mixture. In addition to standard colours, you can also add metallic pigments based on iron oxides that imitate a silver or gold substrate.

The number of spraying nozzles is selected for the width of the paper web, with the distance between the nozzles depending on the type of sprayer used and the nature of the expected pattern.

Another factor involved in the final formation of the decoration is the way the carrier web is guided. When the place of application of the ink is in a place where the web is guided vertically, the effect of gravity has a significant impact on the final appearance of the pattern. Characteristic elongations in the details of the pattern are created on the vertical section of the web which is in many cases the desired result.

The curing of the decorative surface begins with the feeding of the carrier web with wet layers of ink and mixture into the drying chamber of the coating machine. The hot air tunnel is optimally used to quickly evaporate water over the entire width of the carrier web. Determining the proper curing of the decorative layer can be assessed by measuring residual moisture using laboratory techniques.

Another element determining the final result is the concentration of ink. The amount of pigment relative to the aqueous solvent also affects the pattern applied to the carrier. It is important to choose the right ink nozzles, in particular the size of the nozzles, which can be important during a long-term production process. An important parameter when adjusting the spray jet is the amount of pressure applied to the ink tanks or to the spray nozzles themselves.

An advantage of the invention is that the technical means involved in obtaining the final surface is a coating machine that allows printing in an online process. The option of maintaining machine parameters, such as web feed speed or settings of the unit applying a layer of thickened water, allows for a certain tendency to obtain a repeatable nature of the decorations produced.

In order to better illustrate the inventions and the visual patterns obtained as a result of the method according to the invention, the illustration comprises the following figures:

fig. 1 and fig. 3 - schematic diagram of an online process using the Meyer Bar system;

Fig. 2 is a schematic diagram of an online process using a three-roll system; Fig. 4 is a schematic diagram of an online process using a pouring system;

Fig. 5 is a cross-section through an Ebru surface that is not the subject of the invention;

Fig. 6 is a cross-section through a surface according to the invention;

fig. 7a to 17 - the visual result of the decorative surfaces obtained by the methods in examples 2-12; Fig. 18a to 18e - visual result of comparative surfaces.

The following non-limiting examples provide individual and advantageous solutions to the method and product according to the invention. When referring to parts of a mixture, it should always be understood as parts by weight. The titles of examples are merely conventional and have been given for the purpose of giving structure to the document.

Types of spray nozzles used in the examples:

Embodiment 1 : The product containing a new surface with a cross-section as in Fig. 6, consists of a bottom layer which is a carrier 2 in the form of impregnated paper web, on which there is an intermediate layer C formed from the solid particles of the surface tension increasing additive, remaining after the water evaporates from the mixture. The top layer B covers only selected fragments of the intermediate layer C and it consists of ink droplets that have expanded and dried in the drying tunnel. For comparison, Fig. 5 is a schematic cross-sectional view of the surface obtained in the traditional Ebru art method, which achieves its final result by applying a composition of water and inks on paper in one step. This method determines the formation of a ink layer B adhering directly to the carrier A, which is always a sheet. On the other hand, on the top layer C forms a thin coating of solid particles, remaining after water evaporation.

Embodiment 2: Hologram effect - the addition of tragacanth gum.

On a known production line as in Fig. 1 consisting of an impregnated paper coating machine, a roll of carrier 1 in the form impregnated paper web 2 with a width of 2200 mm is unwound. The web is fed to the Meyer Bar 7 coating station at a speed of 50 m/min. Immersed in the tub 3 containing the liquid mixture 4, the smooth application roller 5 reaches a rotational speed equal to 110% of the web feed speed and applies a liquid layer of the mixture onto the paper. The solution consists of 97.5 parts of water and 0.5 parts of a surface tension increasing additive - tragacanth and 2 parts of gold metallic pigment. The viscosity of mixture 4 is 12.7 seconds measured with a Ford viscosity flow cup, whose discharge diameter is 4 mm. The excess liquid substance is adjusted by a Meyer rod 6, which sets the layer at 120 ml/m ² . Then the carrier 2 with the mixture layer 4 moves to the ink spray zone 8, which consists of four ALBUZ® flat spray nozzles. Nozzles in zone 8 placed on one level at a distance of 105 cm from the paper web, connected to the ink tank, apply white Arcolour ink, which contains titanium white as an ingredient.

Ink viscosity measured with a Ford viscosity flow cup is 12.5 seconds. The ink stream is deposited on the wet layer applied to the paper and creates a unique marble pattern shown in Fig. 7a. In addition, the hologram effect is obtained, i.e. a different image can be seen from various viewing angles, the intensity of which decreases with distance from the central point of the ink droplet (Fig. 7b). The process of curing the decoration starts when the web enters the drying tunnel 9. The temperature of the drying chamber is 220°C. The finished product is wound on a roll in the winding station 10.

Embodiment 3: Effect of gravity - the addition of xanthan gum.

On a known production line as in Fig. 2, consisting of an impregnated paper coating machine, a roll of carrier 1 in the form impregnated paper web 2 with a width of 2200 mm is unwound through a 3WS 11 coating station three-roll system, a mixture 4 is applied which has viscosity of 12 seconds and consists of 99.5 parts of water and 0.5 parts of a surface tension enhancing agent - xanthan gum. After collecting the excess wet layer and setting the application rate at 60 ml/m ² , white ink is sprayed at one spraying level. After drying in the drying tunnel, the result shown in Fig. 8 is obtained. The direction of the ink distribution can be seen, which mainly depends on the paper web being guided vertically. Other factors that have a significant impact on the shape and size of decoration elements are the viscosity of the ink and priming mixture, and the thickness of the primer layer.

Embodiment 4: The fine marble pattern - 1 colour - the addition of acetylated starch.

The process is similar to embodiment 2, with the carrier 2 being decorative paper, on which a layer of the aqueous mixture 4 is applied, which consists of 2 parts of a surface tension enhancing agent - acetylated starch and 98 parts of pure water. Excess liquid is adjusted with a Meyer rod 6, which sets the amount at 120 ml/m ² . Then ink is applied to the carrier web 2 covered with the mixture 4 in the ink spray zone 8, at one height level at a distance of 95 cm from the paper. The viscosity of the undercoat mixture is 16 seconds and 12.9 seconds for the ink measured with a Ford viscosity flow cup. After drying, the result can be seen in Fig. 9.

Embodiment 5: The thick marble pattern with a golden primer - the addition of gellan gum.

The procedure is similar to embodiment 2, with the mixture consisting of 97.5 parts of water, 2 parts of gold pigment and 0.5 part of gellan gum acting as a surface tension enhancing agent. The application rate of layer covering the carrier is set at 120 ml/m ² . The web moves to the ink-spraying section 8 with nozzles increasing droplet size, located on one level at a distance of 100 cm from the paper. The viscosities of the liquid are 12.8 seconds for the primer mixture layer and 12.5 seconds for the ink layer. Fig. 10 shows the obtained image in this embodiment.

Embodiment 6: The spilled marble pattern - the addition of an agent based on methylcellulose which is wallpaper glue.

The method of obtaining decorations is similar to that in embodiment 2. Carrier 2, which is black impregnated paper, is covered with a layer of a mixture 4 consisting of 97 parts of water, 2 parts of silver pigment and 1 part of a surface tension enhancing agent - Henkel Metylan Special wallpaper adhesive. The Meyer rod 6 levels the layer, setting the application rate at 120 ml/m ² . The web with a wet layer of the 12.7-second viscosity mixture moves to the ink spray zone 8 containing the spray nozzles, 100 cm away from the paper web. In this embodiment the use of a black water ink with a viscosity of 13 seconds is assumed. The formation of decorations is quite intensive, a large spill of black ink can bee seen, caused by the thickness and viscosity of the applied primer mixture 4. The black carrier 2 used in the embodiment additionally promotes the high contrast between the silver primer and the black pigment, as seen in Figure 1 1 .

Embodiment 7: The fine marble pattern - 4 colours - the addition of tragacanth rubber.

The procedure is similar to that in embodiment 2. On impregnated paper carrier web 2, a mixture 4 with an application rate of 74 ml/m ² is applied, consisting of 97.5 parts of water, 2 parts of metallic gold pigment and 0.5 parts of tragacanth gum acting as a surface tension enhancing agent. The application of ink to the wet layer of the carrier web 2 is carried out from the ink spray zone 8, consisting of four rows of spray nozzles, mounted on strips fixed at different heights. The height level difference is 50 cm, and the nozzles are 100 cm away from the web. Four basic inks were used in this embodiment, i.e. red, yellow, black and blue, with viscosities of 12.2 seconds. The applied layer of the golden mixture primer in combination with the ink application shows the decoration shown in Fig. 12. Embodiment 8: The result after gravitational dripping on a horizontal ribbon - the addition of tragacanth gum.

On a known production line as in Fig. 3 consisting of an impregnated paper coating machine, a roll of carrier 1 in the form impregnated paper web 2 with a width of 2200 mm is unwound. On an impregnated paper carrier web 2, a layer of a mixture 4 of 99.5 parts of water and 0.5 parts of tragacanth gum is applied, acting as a surface tension enhancing agent. The application rate of the layer was set at 120 ml/m ² . Then, on the wet layer of the carrier 2 applied using this method, located on the horizontal section, ink with a viscosity of 10.8 seconds is dripped gravitationally. Droplets are transferred by a specially constructed dripper 12, which is a cylindrical strip with pre-drilled holes with a diameter of 0.5 mm. The spot for applying ink is just before the carrier web 2 enters the drying tunnel 9. The distance of the dripper 12 from the paper web is 75 cm. The result of this method are decorative motifs with a snowflake-like appearance about 90 mm in diameter with an obvious centre point about 18 mm in diameter. The appearance of a single decorative element is shown in Figure 13.

Embodiment 9: The irregular marble pattern - the addition of an agent based on methylcellulose which is wallpaper glue.

The method of obtaining decorations is similar to the in embodiment 2. Impregnated paper carrier web 2 is covered with a water mixture 4 with a viscosity of 12.2 seconds. Mixture 4 consists of 95 parts water, 2 parts green pigment, 2 parts silver metallic pigment and 1 part surface tension enhancing agent - Henkel Metylan Special wallpaper adhesive. The application rate of layer of mixture 4 on paper is set at 74 ml/m ² . Next, ink stream is generated from two rows of ink spray zone 8, located on two nozzle levels, 50 cm apart and 105 cm from carrier web 2. Yellow and red inks with viscosities of 12.4 seconds form an irregular pattern. The characteristic marble pattern is very diverse in size and chaotic, which can be seen in Fig. 14.

Embodiment 10: Marble effect on Biaxially Oriented Polypropylene (BOPP Film) - the addition of gellan gum.

Carrier 2 in the form of Biaxially Oriented Polypropylene (BOPP Film) is delivered from carrier roll 1 to the start of the process. The film web is fed to the 3WS coating station - three-roll system 11 , at a speed of 50 m/min, as in Fig. 2. The application roller 13 achieves a rotational speed of 150% of the advance speed of the carrier web 2 and applies a liquid layer of the mixture 4 to the film 2. Mixture 4 consists of 99.5 parts of water and 0.5 parts of a surface tension enhancing agent - gellan gum. The viscosity of mixture 4 is 12.7 seconds measured with a Ford viscosity flow cup, whose discharge diameter is 4 mm. The application rate of mixture 4 is 30 ml/m ² . Then the carrier web 2 with the mixture layer is moved to the ink spray zone 8 with the spray nozzles. The ink application unit consists of spray nozzles connected to the ink tank and placed on one level at a distance of 105 cm from the film web. Ink viscosity measured with a Ford viscosity flow cup is 12.5 seconds. The ink stream is deposited on the wet layer applied to the film web and creates a unique marble pattern shown in Fig. 15. The process of curing the decoration starts when the web enters the drying tunnel 9. The drying chamber temperature is 50°C. The process ends at winding station 10.

Embodiment 1 1 .The procedure is as in Embodiment 10, wherein after applying the layer of the mixture 4, the carrier web 2 is shifted to the dripper system 12. The spot for applying ink is just before the film web enters the drying tunnel 9. The distance of the dripper 12 from the paper web is 75 cm. The result of this method is the pattern shown in Fig. 16.

Embodiment 12: The effect of expanding drop on a textile fabric - the addition of xanthan gum.

Carrier web 2 in the form of a textile fabric is delivered from the carrier roll 1 to the start of the process. The carrier web 2 is fed to the coating station of the pouring system 15 at a speed of 50 m/min. Mixture 4 consisting of 90 parts of water and 10 parts of a surface tension enhancing agent - xanthan gum, is gravitationally poured onto the horizontal surface of carrier 2, as shown in Fig. 4. The application rate of layer 4 is 200 ml/m ² . Then the carrier web 2 with the mixture layer is moved to the ink spray zone 8 with the spray nozzles. The ink application unit consists of spray nozzles placed parallel to the carrier web 2 at a distance of 60 cm from its surface. Ink viscosity measured with a Ford viscosity flow cup is 12.5 seconds. The ink stream is deposited on the wet layer of the mixture 4 applied to the fabric and creates a unique pattern shown in Fig. 17. The process of curing the decoration starts when the web of textile fabric enters the drying tunnel 9. The temperature of the drying chamber is 220°C. The process ends at winding station 10.

All methods of obtaining decorative surfaces, described in detail in embodiments 2 to 12, can also be implemented using digitally programmed and / or electronically controlled spray nozzles. Other technical means do not need to be changed, sometimes only their parameters, in accordance with the revealed dependencies. The sequence of activities carried out and their order are also preserved.

Comparative effects - the different application of mixtures while other parameters remain the same.

The purpose of this part of the description is to show the effect of applying the primer layer on the shape of the decoration and the final appearance of the pattern. Five different surfaces a, b, c, d, e were made, whose final appearance is shown in Figs. 18a-e in sequence, where the same ink was applied to the same carrier medium.

Basic specification for all surfaces a, b, c, d, e:

Carrier - impregnated paper with a web width of 2200 mm, ink - white, viscosity 12.5 sec, linear speed of the carrier web - 50 m/min, application of ink over a section of vertically fed carrier web, 100 cm distance between the carrier and spray nozzles, flat spray nozzles with pressure 0.37 MPa, the number of spray nozzles is 4 pieces on a width of 220 cm, spaced every 44 cm.

Additional specification for surfaces b, c, d, e:

A mixture with a viscosity of 12.8 seconds, consisting of 97.5 parts by weight of water, 2 parts by weight of gold pigment and 0.5 parts by weight of Targatan gum, was applied in a Meyer Bar system with rods being replaced each time. a) The ink was applied directly to dry paper. After drying, the image shown in Fig. 18a was obtained. Sprayed ink droplets remain unchanged from the moment the wet ink is absorbed by the paper until they are cured.

b) The application unit is armed with a rod allowing to limit the application rate to 5 ml/m ² . The wet carrier web moves to the ink spray area. The result created after curing can be seen in Fig. 18b. A small amount of primer applied allows the ink droplets to dissolve slightly.

c) The replacement of the Meyer rod allowed the mixture to be applied with a rate of 70 ml/m ² . The result created after curing can be seen in Fig. 18c. d) The rod was subsequently replaced, resulting in a layer of mixture at a rate of 120 ml/m ² . The result created after curing can be seen in Fig. 18d.

e) The last replacement of the Meyer rod allowed the mixture to be applied with a rate of 200 ml/m ² . The result created after curing can be seen in Fig. 18e.

As the thickness of the mixture layer increases, the ink dissolves to form interacting conglomerates. A characteristic marble pattern is created, clearly seen in Fig. 18c and Fig. 18d. The last version, with the largest application rate, depicts the disappearance of the expected effect. The ink spills over the surface of the mixture, and the mixture itself flows down from the surface of the carrier - Fig. 18e. The effect is enhanced by vertical carrier web transport over several meters, until the direction of the web is changed towards the drying chamber.

List of symbols

1. carrier web roll

2. carrier web

3. tub

4. mixture

5. smooth roller

6. Meyer's rod

7. Meyer Bar arrangement

8. ink spray zone

9. drying tunnel

0. decorative web winding station

1. 3WS application station - three-roller system 2. dripper

3. application roller

4. guide rollers

5. pouring system