Patent ID: 12194757

EXAMPLE 1A: PRINTING ON RAW PAPER

A raw paper (paper weight: 80 g/m2) is unrolled from an unwinding device.

A decorative layer is applied by digital printing using a CRYK ink with the following composition;

Total pigmentPigmentcontentSolventWaterCPC 15:3Max. 2%42%56%RPY254 48%Max. 7%30%63%PR207 48%PY181 4%YPY 150Max. 4%37%59%KPBL 7Max. 4%36%60%

Glycol is the preferred solvent.

The printing inks are applied in a quantity between 5 and 10 g/m2.

The printed paper can be provided with a melamine-formaldehyde resin layer as a protective layer after printing. This protective layer serves to protect the printed decorations and enables intermediate storage.

The paper is then dried in a convection dryer or by NIR (near infrared) to a moisture content of approx. 6 wt % so that the resin layer is in the B state.

EXAMPLE 1B: PRINTING ON RAW PAPER WITH INK-RECEIVING LAYER

A raw paper (paper weight: 80 g/m2) is unrolled from an unwinding device. Then a pigmented (TiO2) ink-receptive layer (synthetic silicate with polyvinyl alcohol as binder) (layer thickness 40 μm; after drying at 125° C. dry basis weight 4 g/m2) and a primer layer are applied and the layer structure is dried.

After drying, a decorative layer is applied to the paper thus obtained (paper weight: 80 g/m2) by digital printing using a CRYK ink with the above composition. The inks are applied in an amount between 5 and 10 g/m2.

The printed paper can be provided with a melamine-formaldehyde resin layer as a protective layer after printing. This protective layer serves to protect the printed decorations and allows for intermediate storage.

The paper is then dried in a convection dryer or by NIR (near infrared) to a moisture content of approx. 6 wt % so that the resin layer is in the B state.

EXAMPLE 2A: PRINTING OF A FIRST IMPREGNATE WITH INK-RECEIVING LAYER

The paper to be printed is impregnated on the front and back with a liquid melamine resin in an impregnation device. Approx. 50 g melamine resin/m2with a solids content of approx. 50% is applied.

Subsequently, a pigmented (TiO2) ink receptive layer (synthetic silicate with polyvinyl alcohol as binder) (layer thickness 40 μm; after drying at 125° C. dry basis weight 4 g/m2) and a primer layer are applied and the layer structure is dried.

After drying, a decorative layer is applied to the resulting impregnate (paper weight: 80 g/m2) by digital printing using a CRYK ink with the above composition. The inks are applied in an amount between 5 and 10 g/m2.

The printed paper can be coated with a melamine-formaldehyde resin layer as a protective layer after printing.

The paper is then dried in a convection dryer or by NIR (near infrared) to a moisture content of approx. 6 wt % so that the resin layer is in the B state.

EXAMPLE 2B: PRINTING OF A SECOND IMPREGNATE WITH INK-RECEIVING LAYER

The paper to be printed is coated with melamine resin powder in an application device in a quantity of 25 g/m2using tribo guns. The melamine resin powder contained the usual additives such as hardeners, release agents, etc. The powder is then melted-on by infrared radiation.

Subsequently, a pigmented (TiO2) ink receptive layer (synthetic silicate with polyvinyl alcohol as binder) (layer thickness 40 μm; after drying at 125° C. dry basis weight 4 g/m2) and a primer layer are applied and the layer structure is dried.

After drying, a decorative layer is applied to the resulting impregnate (paper weight: 80 g/m2) by digital printing using a CRYK ink with the above composition. The inks are applied in an amount between 5 and 10 g/m2.

The printed paper can be coated with a melamine-formaldehyde resin layer as a protective layer after printing.

The paper is then dried in a convection dryer or by NIR (near infrared) to a moisture content of approx. 6 wt % so that the resin layer is in the B state.

EXAMPLE 2C: PRINTING A THIRD IMPREGNATE

The paper to be printed is impregnated on the front and back with a melamine resin in an impregnation device. Approx. 50 g melamine resin/m2with a solids content of approx. 50% is applied.

Before the dryer, the resin on the side of the impregnate to be printed is removed with a special device (e.g. a knife doctor blade) so that fibres remain free to receive the printer's ink.

After drying, a decorative layer is applied to the resulting impregnate (paper weight: 80 g/m2) by digital printing using a CRYK ink with the above composition. The inks are applied in an amount between 5 and 10 g/m2.

Further drying of the printed impregnate is not necessary as the digital printing ink introduces only little moisture.

EXAMPLE 3: PRINTING A BOARD WITH LIQUID OVERLAY

An HDF board (fibreboard with increased bulk density) is first pre-coated with an aqueous synthetic resin (melamine-formaldehyde resin). The application quantity is 20-50 g resin liquid/m2(solids content: approx. 55%). The resin contains the usual additives such as wetting agents, hardeners, release agents and defoamers. Afterwards, the applied resin is dried in a convection dryer or a near-infrared oven to a humidity of approx. 20%. Then several coats of a water-based, pigmented base coat are applied (5-8 x). After each application, the base coat is dried using a convection dryer or a near-infrared dryer.

In the following, the base coated panel is printed with a motif using a digital printer. Approx. 6-8 g/m2of the water-based CRYK digital printing ink is used.

After the decorative layer has dried, approx. 70 g of melamine resin fl. (solids content: 55% by weight) containing the usual additives (hardener, wetting agent, etc.) is applied to the printed panel surface in a first roller application unit. A melamine resin is also applied to the underside of the board with the first roller application unit (application quantity: 60 g resin fl./m2, solids content: approx. 55% by weight).

Afterwards, 14 g corundum/m2(F 200) are sprinkled on the surface with a sprinkling apparatus. A distance of approx. 5 m to the dryer allows the corundum to sink into the melamine resin. The board then passes through a circulating air dryer. Then a melamine resin layer (solids content: 55% by weight) is applied in a quantity of 25 g/m2. This also contains the usual additives. A melamine resin is also applied to the underside of the board using a roller application unit (application quantity: 50 g resin fl./m2, solids content: approx. 55 wt %). Again, the board is dried in a circulating air dryer.

Then a melamine resin is applied to the surface of the board, which also contains glass beads. These have a diameter of 60-80 μm. The application quantity of the resin is approx. 20 g melamine resin fl./m2(solids content: 61.5 wt %). In addition to the hardener and the wetting agent, the formulation also contains a release agent. The application quantity of glass beads is approx. 3 g/m2. A melamine resin is also applied to the underside of the board with a roller application unit (application quantity: 40 g resin fl./m2, solids content: approx. 55 wt %). The board is again dried in a circulating air dryer and then coated again with a melamine resin containing glass beads. Another component is cellulose (Vivapur 302). Again, approx. 20 g melamine resin fl./m2(solids content: 61.6 wt %) are applied. Again, approx. 3 g glass beads and 0.25 g cellulose/m2are applied. In addition to the hardener and the wetting agent, the formulations also contain a release agent. A melamine resin is also applied to the underside of the board using a roller application unit (application quantity: 30 g resin fl./m2, solids content: approx. 55% by weight). The resin is again dried in a circulating air dryer and then the board is pressed in a short-cycle press at 200° C. and a pressure of 400 N/cm2. The pressing time was 10 seconds. A press plate with a wooden structure was used as the structure generator.

EXAMPLE 4: PRINTING A BOARD WITH POWDER OVERLAY

In a production line, 8 mm HDF is separated, cleaned of dust with the help of brushes and then transported further via roller conveyors.

In an application device, they are then coated with melamine resin powder in an amount of 25 g/m2using tribo guns. The melamine resin powder contained the usual auxiliary materials such as hardeners, release agents, etc. The powder is then melted-on by infrared radiation.

Afterwards, the base coated panel is coated with a colour base coat in multiple coats with subsequent intermediate drying (circulating air). The colour base coat is a mixture of casein and pigment (titanium dioxide). The application quantity per coat is approx. 5 g fl./m2. The application is repeated at least five times. This is followed by the application of a primer (application quantity: 10-20 g fl./m2) with circulating air drying.

Afterwards, the panel is printed with a digital printer using the aqueous CRYK ink. The application rates of ink are 3 to 15 g fl./m2. The ink is dried via IR radiation or circulating air.

Corundum is sprinkled onto the print with a sprinkling device (application quantity: 20 g corundum/m2, F 180).

Afterwards, melamine resin powder is again applied with a tribo gun (application quantity: 80 g/m2). This melamine resin powder is again gelled with the help of an IR radiator. The melamine resin powder contained the usual additives such as hardener, release agent, etc.

The board is then pressed in a KT press together with a counter-impregnate. The pressing conditions were: T=200° C., p=40 kg/cm2and t=25 sec. The pressed panel was then visually inspected and no abnormalities were found. The surface tests subsequently carried out in accordance with DIN EN 15468—August 2018 also showed no abnormalities. All requirements of stress class 32 were met.