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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
• • 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
  • B41M5/025—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet
  • B41M5/035—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic
  • B41M5/0358—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet by sublimation or volatilisation of pre-printed design, e.g. sublistatic characterised by the mechanisms or artifacts to obtain the transfer, e.g. the heating means, the pressure means or the transport means
• • 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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/267—Marking of plastic artifacts, e.g. with laser

Definitions

• the invention relates to a method for producing color-printed plastic surfaces by applying a dye to the plastic surface by means of LASER radiation.
• Nd YAG LASER (wavelength: 1064 nm) or a frequency-doubled Nd: YAG LASER (wavelength: 532 nm) preferably being used.
• a specifically adjustable color change cannot be implemented flexibly: In general, only light fonts on a dark background or dark fonts on a light background are possible. Furthermore, the color change is strongly influenced by the plastic to be labeled.
• the object of the present invention is to find a method which avoids the disadvantages mentioned and with which colored characters can be applied flexibly and at low cost to a plastic surface of constant quality.
• the selection of dyes to be transferred and the selection of plastics to be labeled should be as large as possible. In addition, the effects of carbonization and combustion of the substrate plastic should be minimized.
• the invention thus relates to a method for inscribing plastics, in which a carrier material which is provided with a sublimable dye is pressed against the plastics to be inscribed, preferably by means of a LASER emitting in the visible wavelength range, preferably a frequency-doubled Nd: YAG LASER ( Wavelength: 532 nm), the plastic surface is provided with colored characters.
• a carrier material which is provided with a sublimable dye is pressed against the plastics to be inscribed, preferably by means of a LASER emitting in the visible wavelength range, preferably a frequency-doubled Nd: YAG LASER ( Wavelength: 532 nm)
• the plastic surface is provided with colored characters.
• the LASER beam causes the dye from a carrier material (transparent at the wavelength of the LASER) to be transferred to the plastic surface.
• part of the LASER energy is absorbed in the substrate material, as a result of which the dye is fixed on the plastic surface.
• a frequency-doubled Nd: YAG laser is the Wavelength 532 nm. This can be guided over the carrier material in such a way that the plastic surface can be provided with the desired signs or symbols. Since dyes usually absorb - at least partially - in the visible region of the wavelength spectrum, the radiation energy is absorbed in the dyes at 532 nm. As a result, these diffuse from the carrier material onto the plastic surface.
• the carrier material should generally not absorb at the wavelength of 532 nm, while the plastic surface to be printed supports the fixation of the diffusing dye by energy absorption. Subsequent fixation is also possible. This can be achieved either by conventional heat sources, or LASER radiation in a second radiation step, or by infrared radiation. It is also possible to first pre-label the substrate without a carrier material and then in a second step to carry out a colored labeling using a carrier film. Under certain circumstances, this can increase the adhesive strength of the lettering.
• the carrier material provided with dye is pressed firmly onto the material to be labeled, because this causes the energy transfer to be focused sharply onto the surface to be labeled and extremely sharp contours form. Additional aids can also be used to support the pressing.
• Suitable parameters of the LASER used are: The repetition frequency is in the range from 1 to 20, preferably 4 to 6 kHz, the lamp current in the range from 15 to 25, preferably at 20 A and the speed in the range from 5 to 50, preferably 20 up to 30 mm / sec.
• Suitable dyes or mixtures of dyes have proven to be those which are applied to a carrier material in the form of a film or a coating and which sublime with a low energy input. These are known and are described, for example, in Color Index. This also includes products sold under the names (R) Lurafix (manufacturer BASF AG, Ludwigshafen, Federal Republic of Germany) or (R) Resiren (manufacturer Bayer G, Leverkusen, Federal Republic of Germany).
• suitable carrier materials which generally do not absorb energy at all or only slightly absorb it at the wavelength of the frequency-doubled YAG LASER are e.g. Polyethylene, polypropylene or polyester films, preferably polypropylene films are used.
• Suitable plastic materials are those which at least partially absorb the radiated energy of the wavelength of the frequency-doubled YAG LASER.
• suitable fillers, dyes and / or pigments that allow such absorption are added to the plastic materials.
• Preferred plastics are e.g. Polyacetals, such as polyoxymethylene homo- and copolymers, polyesters, such as polyethylene terephthalate and polybutylene terephthalate, liquid-crystalline polyesters, polyarylene sulfides, and also polypropylene provided with reinforcing agents and / or fillers, whose copolymers with other monoolefins and whose blends with impact modifiers. Mixtures of different polymers can also be used.
• fillers such as chalk, mica, talc, feldspar, wollastonite, aluminum silicate, furthermore antioxidants, light stabilizers, flame retardants, heat stabilizers, reinforcing agents such as glass fibers, or processing aids which are used in the processing of plastics are common.
• the molded parts produced from the plastic molding compositions by conventional methods can be of any type and size, which are then labeled using the method according to the invention.
• the labeled molded parts can be used in all fields of technology, for example in the labeling of containers (cans and foils), in the electronics and power and air vehicle industries, in device construction, in apparatus engineering and in other fields of application known to the person skilled in the art.
• a polypropylene film printed flat with the dye (CI Disperse Red 60, CI 60756) is placed on a plate-shaped plastic test specimen made of polyoxymethylene (POM) with an MFI (2.16 kg, 190 ° C) of 9 g / 10 min. placed and exposed to the radiation of a frequency-doubled Nd: YAG laser (wavelength: 532 nm). The repetition frequency was 5 KHz, the lamp current was 20 A and the speed was 25 mm / sec. During the radiation period, the LASER beam was moved in such a way that characters appeared on the test specimen. After removing the film, the dye in the irradiated zone penetrated the plastic and gave a perfect typeface.
• POM polyoxymethylene
• Example 1 was repeated using sublimation dyes of a different color instead of the red dye, which likewise gave uniform results.
• Example 1 was repeated, using a flat printed polyethylene film instead of a polypropylene film printed with CI Disperse Red 60. The result was similar to that of Example 1. 6 to 9)
• Example 1 was repeated, using instead of POM plate-shaped specimens from other plastic molding compositions.
• Example 1 Sublimation dye plastic 6 CI Disperse Red 60 Polybutylene terephthalate 7 CI Disperse Red 60 reinforced polypropylene 8th CI Disperse Red 60 Polyphenylene sulfide 9 CI Disperse Red 60 liquid crystalline polyester
• Example 1 Example 1 was repeated, with a plate-shaped plastic molded body made of polybutylene terephthalate being initially labeled without the use of a colored film solely by the action of laser beams.
• a polypropylene film printed with CI Disperse Red 60 was then placed on the test specimen and, this time in color, labeled according to Example 1. An abrasion-resistant lettering resulted.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6475132

Family Applications (1)

Country Status (5)

Cited By (3)

Citations (3)

• 1993
  • 1993-12-07 EP EP93119711A patent/EP0605803A1/fr not_active Ceased
  • 1993-12-09 FI FI935528A patent/FI935528A/fi unknown
  • 1993-12-10 MX MX9307866A patent/MX9307866A/es unknown
  • 1993-12-10 NO NO934537A patent/NO934537L/no unknown
  • 1993-12-10 CA CA 2111162 patent/CA2111162A1/fr not_active Abandoned
  • 1993-12-10 NO NO934537D patent/NO934537D0/no unknown

Patent Citations (3)

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