Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/0011—Pre-treatment or treatment during printing of the recording material, e.g. heating, irradiating
  • B41M5/0017—Application of ink-fixing material, e.g. mordant, precipitating agent, on the substrate prior to printing, e.g. by ink-jet printing, coating or spraying
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/502—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording characterised by structural details, e.g. multilayer materials
  • B41M5/508—Supports
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C5/00—Processes for producing special ornamental bodies
  • B44C5/04—Ornamental plaques, e.g. decorative panels, decorative veneers
  • B44C5/0469—Ornamental plaques, e.g. decorative panels, decorative veneers comprising a decorative sheet and a core formed by one or more resin impregnated sheets of paper

Definitions

• the invention also relates to a method for producing a panel, in which a correspondingly produced decorative paper is used.
• Methods of this type have long been used to produce decorative papers, which are used, for example, in the production of laminate panels or furniture panels.
• the decorative paper produced in this way is then impregnated with a synthetic resin or polyurethane, for example, and then pressed with a core, for example using a short-cycle press.
• a synthetic resin or polyurethane for example
• a core for example using a short-cycle press.
• This can be in the form of a wood-based panel, for example. High demands are placed on the quality of the printed image of the decor printed on the decor paper.
• paper that is to be printed must have a defined smoothness in order to produce a constant print image.
• the smoothness of the paper side to be printed is a parameter that affects the print quality. Large fluctuations in smoothness sometimes have a serious impact on the visual color impression that the viewer gets.
• a typical smoothness of The upper side of print base papers, i.e. papers that are printed with a decor is around 100 to 200 Bekk seconds for digital printing.
• the smoothness is adjusted during paper manufacture by moistening the upper side with steam and then smoothing it with steel cylinders under pressure.
• the smoothness is a parameter that is partially reversible and changes due to the absorption of moisture, for example from the humidity in the air. The absorption of moisture reduces the smoothness as the fibers of the paper swell up a little.
• the underside of the paper rests on a screen, which is also known as felt. This is called the screen side and is not treated separately and is usually not intended for printing. Opposite the underside is the so-called beautiful side, i.e. the upper side, of the paper, which is intended for printing and is treated accordingly.
• the smoothness of the beautiful side is set by the paper manufacturer.
• the top side of the paper is sensitive to the absorption of moisture, which impairs the surface properties, in particular the smoothness of the top side, and thus changes the printed image and the visual impression.
• the paper absorbs the primer, which is also known as the undercoat, and the ink that is subsequently applied unevenly, so that relatively large amounts of liquid have to be used to create a homogeneous, reach printable layer.
• a consistently high print quality and a homogeneous optical and visual impression over a long period of time can only be achieved and maintained with great effort.
• the invention is therefore based on the object of specifying a method for producing a decorative paper in which the quantity of the primer used and/or the inks used can be reduced without there being a loss in print quality.
• the invention solves the problem set by a method according to the preamble of claim 1, which is characterized in that the upper side of the unprinted base paper has a smoothness of less than 70 Bekk seconds.
• Smoothness is measured under standard conditions.
• the measurement is carried out according to the ISO 5627:1995 standard.
• the measuring device is approved for measurements according to this standard.
• the samples are preferably stored in the measurement laboratory for one hour to allow them to acclimate. This duration is sufficient, since the samples in the specific application come from the pressroom, which is also air-conditioned. If the climate parameters, such as temperature or humidity, are very different between these two rooms, a longer acclimatization period may be useful or necessary.
• the paper moisture is between 2% and 4%, the temperature of the laboratory climate is 23 °C (+- 1 °C) and the relative humidity is 50% (+- 2%).
• the size of the paper sample to be measured should be at least 38.5 cm 2 , which corresponds to a circular paper sample with a diameter of 70 mm. This ensures that the entire measuring area can be covered.
• the area where the sample is placed is approximately 50mm in diameter, with the actual measurement area being 37.4mm in diameter.
• the sample to be measured is positioned between a measuring head, which is designed as a flat ground glass ring, and a rubber pressure plate, with the side to be measured pointing to the measuring head.
• the glass ring has a contact area of 10 cm 2 .
• the pressure plate presses the sample against the glass plate with 100 kPa.
• the measuring head is connected to a chamber in which a negative pressure is generated and which has a volume of 380 ml.
• the measuring head and pressure plate move together.
• the negative pressure generated then sucks air into the chamber between the measuring head and the sample.
• the initial pressure is 50.7 kPa.
• the measurement is stopped at 48.0 kPa, then 10 mL of air has been drawn into the chamber.
• the smoother the paper surface the longer it takes for the defined amount of air to be sucked into the chamber.
• the smoothness describes the time in which a certain amount of air is sucked through at a defined pressure difference between the paper surface and the measuring head. The result is given in Bekk seconds.
• the upper side By using the upper side with less smoothness, a strong pre-treatment of the paper is unnecessary and thus a strong swelling of the fibers due to the absorption of moisture is avoided. This also reduces unsteady surfaces during printing.
• the primer that is applied to the unprinted base paper stands more evenly on the paper surface, so less ink has to be used. This reduces or completely avoids subsequent problems that occur, for example, during impregnation and later pressing. Since the paper does not have to be smoothed as much during its production as is the case with papers from the prior art, it is subsequently less susceptible to the effects of moisture and the printed surface appears smoother.
• the upper side of the unprinted base paper preferably has a smoothness of less than 60 Bekk seconds, preferably less than 50 Bekk seconds and more than 40 Bekk seconds.
• the upper side of the unprinted raw paper which is provided with the primer and then printed with the inks of the decoration, is the wire side of the raw paper opposite the beautiful side of the raw paper.
• it is not smoothed as much or not at all during the manufacture of the paper and is therefore less smooth, but is more even.
• smoothing the beautiful side of the paper it becomes smoother, but the structure of the However, fibers are damaged and torn, making the beautiful side more susceptible to the effects of moisture.
• the primer is preferably applied in an amount of at most 6 g/m 2 , preferably at most 5 g/m 2 .
• the decoration is particularly preferably printed with an amount of ink between 0.5 g/m 2 and 8 g/m 2 .
• the upper side of the unprinted base paper preferably has a corresponding smoothness at every point.
• the parameter is measured and monitored across the entire width of the paper web being printed.
• the impregnated decorative paper and the core are preferably pressed together in a short-cycle press.
• the core preferably contains a wood-based panel or is a wood-based panel.

Landscapes

• Laminated Bodies (AREA)

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Publications (1)

Family

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Family Applications (1)

Country Status (1)

Citations (2)

• 2022
  • 2022-01-26 EP EP22153516.4A patent/EP4219178A1/fr active Pending

Patent Citations (2)

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