Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/14—Security printing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/06—Veined printings; Fluorescent printings; Stereoscopic images; Imitated patterns, e.g. tissues, textiles

Definitions

• the invention relates to a decorative sheet usable for the manufacture of laminated panels, this sheet further comprising means of recognition and security.
• the invention further relates to a composition to print such a sheet.
• laminates have been used as materials in dwellings and premises commercial and industrial. Typical applications of such laminates are the surface coating of walls, table tops, furniture and more.
• the so-called high pressure laminates are produced from a core consisting of sheets impregnated with resin.
• the sheets are generally sheets of kraft paper which has been impregnated with a thermosetting resin and more particularly of a phenolic resin.
• the sheets are dried, cut, then stacked on top of each other.
• the number of sheets in the stack depends on the applications and can vary between 3 and 9, but can be higher.
• a decorative sheet which is generally a sheet of paper bearing a printed or light-colored pattern, and impregnated with a non-blackening thermosetting resin not heat, for example melamine-formaldehyde resins, benzoguanamine-formaldehyde resins, unsaturated polyester resins.
• a protective cover sheet devoid of pattern and transparent in the final laminate. In terms by trade, this protective sheet is called "over-lay”.
• thermosetting resins are transformed into thermoset form and obtains an extremely hard material with a decorative effect.
• the decorative sheet is traditionally made in the following manner.
• We make a sheet of paper by draining an aqueous suspension of long and / or short cellulose fibers on a flat canvas, bleached and / or unbleached, fillers, binders.
• the sheet thus formed is drained, pressed and dried to form a sheet of paper.
• This sheet is then printed.
• the usual impression is a rotogravure printing using engraved rollers.
• the engraving technique consists of making a drawing, for example reproducing a wood or a purely fancy artistic drawing.
• one or more printing rollers are engraved.
• Each cylinder then passes through an ink bath, and the indentations or imprints engraved in the cylinder are filled ink which is then transferred to the paper.
• one to five separate prints are made and successive using one to five rollers.
• the gravure printing process allows from a drawing to print a sheet of paper.
• this poses a problem for the printer of the decorative sheet. Indeed, if the drawing is a original drawing, created by the printer, any other printer, from a printed decorative sheet, may have photographs taken of this sheet and have cylinders engraved for the same impression. Counterfeits can therefore be numerous and it is generally not possible to detect them or have intangible proof that these are counterfeits.
• the invention therefore aims to solve this problem.
• Another problem that arises is the identification of the laminate manufacturer. Indeed, the sheet maker decorative can sell the same authentic sheet to several laminate manufacturers. Each manufacturer of laminate generally bears its mark on the laminate, by means of a more or less removable label. Here again, there is the problem of identifying the manufacturer of a particular laminate. The invention aims to solve this second problem.
• An object of the invention is therefore to provide a decorative sheet for laminated panels, comprising means of recognizing the origin of laminates.
• the first design is invisible to natural light and the second design is visible to light artificial.
• natural light is meant a light source whose wavelengths are included between 400 and 700 nanometers and by artificial light, a light source whose wavelengths are less than 400 nanometers and more than 700 nanometers.
• pigments and dyes are luminescent. These materials are commonly called "phosphorus". These pigments can be fluorescent or phosphorescent.
• the feeling of color produced by conventional pigments or dyes which are not luminescent results from selective absorption wavelengths in the visit part of the spectrum. Wavelengths that are not absorbed are reflected or transmitted, which gives the feeling of color. This feeling of color is absent when there is no visible light source, because there is no energy to reflect or transmit.
• luminescent pigments do not reflect light, but they are sources of light themselves. They have the property of absorbing certain wavelengths, generally wavelengths less than 400 nanometers and invisible to the eye, and transform these wavelengths into visible wavelengths. The wavelengths thus emitted produce a feeling of color. When the emission of light continues for a significant period of time, after the excitation energy source has been switched off, the material is said to be phosphorescent.
• Document EP-A-147252 describes a mixture of a luminescent substance and an anti-storage substance. Such a mixture can be used for marking documents to prevent counterfeiting, for example example of bank notes, fiduciary papers.
• the compositions can be introduced on paper and can be introduced into printing inks. These inks are fatty inks, i.e. containing an oil and the printing is done by offset or intaglio. So far, the problem of marking heat resistant sheets that can be used to decorate laminates have never been laid.
• Document AU-A-518 156 describes a sheet of paper comprising at least one printing light-resistant having a first light shade of wavelength between 400 and 700 nm and a second shade different from the first at a wavelength less than 400 nm, printing being an intaglio print. However, it is not a paper usable for the manufacture of laminates.
• Document DE-A-2 910 176 describes a method for characterizing disc packaging using a fluorescent print.
• GB-2,147,542 describes an article printed using fluorescent or synthetic material.
• the document EP 0253 543 describes a printing ink comprising a metallic compound, a compound luminescent and one or more inert compounds. Such ink is used for credit cards.
• an essential technical problem to be solved is the fact that the sheets are intended to be submitted with heat, for a period of several tens of minutes, or even several hours.
• the sheet is subjected to temperatures of more than 100 ° C, for 20 minutes.
• these papers are subjected to high temperatures, especially when hot stamping is carried out.
• Marking sheets for example for laminates, also poses different and additional problems marking paper for banknotes and other security documents.
• the decorative sheets for laminates are necessarily impregnated with a thermosetting resin.
• the impregnated sheet is placed on a particle board or a stack of impregnated kraft paper sheets. Then we press the assembly against a sheet.
• a problem technique posed is that the prints should not transfer from the decorative sheet onto the sheet which must remain sharp.
• a second technical problem to be solved is that during the impregnation, the decorative sheet passes in an impregnation bath.
• the prints should therefore not migrate into the impregnation bath and should not must not pollute it. Indeed, if the impregnation resin is polluted by printing, during lamination posterior, the thermosetting resin creeps under the action of heat and pressure and if it contains luminescent printing substances, these flow at the same time and cause a smear of the final impression.
• the luminescent substances used have a very good resistance to light.
• these sheets can be used for panels used as materials in homes and above furniture and so they are intended to be subjected to the action of light during periods of extended times.
• the Applicant has tried many commercially available luminescent substances and has found that the ones that work well are mineral pigments. Indeed, organic molecules are very sensitive to outdoor conditions and degrade easily in light, as well as in heat.
• the Applicant has been able to use mineral pigments having a very good resistance to light and withstand high temperatures for long periods of time, i.e. higher temperatures at 100 ° C, preferably between 140 and 200 ° C, for example 140-150 ° C for at least 10 min at 2 hours, for example 20 to 30 minutes.
• luminescent substances used according to the invention such that the zinc sulfides or their mixture with other metallic sulfides are heat resistant, for time periods of more than 10 min.
• the luminescent substances are pigments based on zinc sulfide in mixture with cadmium sulfide. These pigments can have a particle size of less than 40 micrometers.
• Pigments of zinc sulfide or zinc sulfide and cadmium which are activated by copper can be used. Their preparation method is known and is for example described in H.W. Leverenz, An introduction to luminescence of solids: S. John, Wiley & Sons, Inc. New York, Chapman & Hall Ltd London, 1950.
• Pigments based on zinc sulfide emitting in various wavelengths have been described in the Patent applications EP-A-34059, EP-A-78538, EP-A-91184 filed by the Japanese company KASEI OPTONIX. Pigments which are well suited are also pigments based on zinc sulphide, produced by the German company RIEDEL DE HAEN.
• mixtures of luminescent substances can be used, provided that they are resistant to light, heat, pressure, as mentioned above.
• This mixture is applied to a sheet of white paper of 90 g / m2 by gravure printing.
• the cylinder was etched by electronic etching, the cells having a depth of 37 micrometers, the height of the frame being 190 micrometers, and the width of the frame being 210 micrometers.
• the size of the pigment particles is approximately 0.1 to 40 micrometers, which allows printing with such cells. You get a paper that is white in daylight, but when it is illuminated by rays ultraviolet, a blue print appears when the white paper turns brown because it does not reflect and does not does not transmit light.
• This sheet is subjected to a temperature of 160 ° C. by placing it between two hot plates for 15 minutes. Then we illuminate the paper with UV rays. The blue print appears again.
• Example 2 The same mixture is made as in Example 1, but the mineral pigment is replaced by an organic pigment which is an N-substituted anthranilic acid of the type described in document DE-A-3225966.
• an organic pigment which is an N-substituted anthranilic acid of the type described in document DE-A-3225966.
• Example 2 The same mixture is made as in Example 1, with pigments sold by the company OPTONIX, under different numbers.
• the light resistance is 3 to 6 measured according to the Wool scale test and the rays resistance ultraviolet is 5 to 6.
• the Wool scale test corresponds to standards NF T 51056 and NF T 51058. It consists in lighting up a sample including printing with a xenon lamp for 90 hours or 300 hours and at compare the sample obtained with strands of wool with shades ranging from 1 to 8, the number 1 corresponding to the degradation of shade, the number 8 corresponding to a non-degradation.
• Paper is printed by heliography, using one to five color prints in the traditional way. This paper is then decorated and has this decorative aspect and visible by lighting in natural light. We then makes a heliography printing by making one to three prints using the mixtures ink from examples 1 to 9. The original drawing is not changed in natural light. When we light the paper in ultra-violet light, the initial drawing disappears and it is the superimposed drawing that becomes visible.
• the invention relates not only to a means of marking and recognizing subject sheets at temperature, and / or pressure and light, for long periods of time, but also concerns a new means of decoration of these leaves.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Textile Engineering (AREA)
• Vascular Medicine (AREA)
• Laminated Bodies (AREA)
• Road Signs Or Road Markings (AREA)
• Pens And Brushes (AREA)
• Printing Methods (AREA)
• Toys (AREA)
• Paper (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (4)

Family

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Family Applications (1)

Country Status (5)

Families Citing this family (3)

Family Cites Families (7)

• 1989
  • 1989-04-26 FR FR8905541A patent/FR2646378B1/fr not_active Expired - Fee Related
• 1990
  • 1990-04-25 DE DE69002997T patent/DE69002997T3/de not_active Expired - Fee Related
  • 1990-04-25 AT AT90401105T patent/ATE93776T1/de active
  • 1990-04-25 EP EP90401105A patent/EP0395496B2/fr not_active Expired - Lifetime
  • 1990-04-25 ES ES90401105T patent/ES2045839T5/es not_active Expired - Lifetime

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