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
  • B41M5/267—Marking of plastic artifacts, e.g. with laser

Definitions

• the invention relates to a shaped article with a marking on a thermoplastic substrate, which marking is made by foaming the thermoplastic by means of high-energy irradiation.
• the invention also relates to a process for the manufacture of the shaped article with a marking on a thermoplastic substrate.
• Such shaped articles are known from EP-A-469982. From this patent specification it is known to make a marking by subjecting a thermoplastic to high-energy irradiation, as a result of which moisture or air present expands and forms bubbles, causing local foaming of the material.
• 'marking' in the present application is understood a pattern containing information, such as an image, an emblem, a logo, a text consisting of letters and/or digits, a code, such as a bar code etc., or a pattern with an aesthetic or decorative function.
• Examples of shaped articles bearing a marking are housings of electronic or electrical equipment, keys, buttons, publicity signs, nameplates, company name signs, etc.
• Other examples are calibrated containers, such as measuring beakers, syringes and coffeemaker reservoirs.
• markings are applied by subjecting the shaped article to high-energy irradiation in the pattern of the marking, for instance by means of a laser beam, causing the synthetic material to foam.
• An advantage of such a marking is that it can be applied very accurately on the desired spot.
• a further advantage is that the shaped articles can be manufactured in series in the known manner without application of a marking, while subsequently any desired marking, different for each individual shaped article, can be applied.
• An additional advantage of such a marking is that it can be applied simply on shaped articles with curved surfaces.
• a drawback of the known shaped article with the marking is that the marking is not abrasion resistant. Fast abrasion of the marking on for instance keys or buttons may result in illegibility, which may be the cause of incorrect setting of equipments and, in consequence, unsafe situations.
• the aim of the invention is to provide a shaped article which does not have this drawback.
• thermoplastic synthetic material contains an agent which, due to the action of the high-energy irradiation, has caused crosslinking at the spot where the foaming of the thermoplastic synthetic material has occurred.
• a further advantage of the shaped article according to the invention is that the marking possesses good resistance to solvents.
• the shaped article may in principle contain any thermoplastic which can be foamed by means of high-energy irradiation in order to serve as substrate for the marking.
• ABS acrylontrile-butadiene-styrene copolymer
• Acrylontrile-butadiene-styrene copolymer is described for instance in EP-A-104695, in which it is described as a polymer composition consisting of:
• Suitable acrylic compounds are acrylonitrile, methacrylonitrile alkyl acrylate, alkyl acrylate or mixtures thereof.
• Suitable vinyl aromatic compounds are styrene and substituted styrene compounds like alpha-methylstyrene, p-vinyltoluene or mixtures thereof.
• the rubber content of the graft copolymer is preferably between 15 and 50 wt% relative to the graft copolymer.
• Suitable rubbers are butadiene rubbers like polybutadiene, butadiene-styrene, butadiene-acrylonitrile or butadiene-acrylate rubber.
• High-energy irradiation of a surface is preferably understood to be irradiation of a surface with a laser beam.
• the agent which brings about the crosslinking does not produce or hardly produces this effect at the processing temperature of the thermoplastic synthetic material, but mainly does so under conditions at which the shaped article is subjected to high-energy irradiation according to the invention, which is accompanied by foaming of the thermoplastic synthetic material.
• the crosslinking by means of the agent can be brought about by the effect of the very high temperature which occurs during the irradiation or by the effect of UV light which can be present in the high-energy rays used.
• a preferred embodiment of the invention relates to the shaped article with the marking on a thermoplastic substrate containing an agent which by the effect of high-energy irradiation brings about the crosslinking.
• An advantage of this embodiment is that only a minor quantity of the agent need be present in the thermoplastic synthetic material, so that the mechanical properties of the thermoplastic synthetic material are preserved better.
• the agent is preferably present in the thermoplastic synthetic material in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the thermoplastic synthetic material.
• the agent preferably is a radical generator. Suitable radical generators are for instance compounds which form carbon radicals, such as 2,3-dimethyl-2,3-diphenylbutane.
• Another preferred embodiment of the invention relates to the shaped article with the marking on a thermoplastic substrate containing an agent which by the effect of high-energy irradiation forms a network within itself.
• a network extends in the form of a co-continuous phase into the foamed thermoplastic synthetic material.
• the agent is preferably present in the thermoplastic synthetic material in an amount of 0.01 to 20 parts by weight per 100 parts by weight of the thermoplastic synthetic material.
• the agent is preferably composed of between 1 and 19 parts by weight of polypropylene glycol per 100 parts by weight of the thermoplastic synthetic material and between 1 and 19 parts by weight of caprolactone polymer per 100 parts by weight of the thermoplastic synthetic material, the sum of the parts by weight of polypropylene glycol and caprolactone polymer being 2-20. In this way it is ensured that the laser marking according to the invention possesses good abrasion resistance, while preserving the mechanical properties of the thermoplastic synthetic material. If the agent is melamine, the particles preferably have a diameter of ⁇ 10 ⁇ .
• the shaped article according to the invention without the marking applied onto it, can be manufactured in accordance with the known processes and irradiated with high-energy radiation in a pattern corresponding to the shape of the marking.
• thermoplastic polymer e.g., polystyrene-butadiene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styren
• the shaped article according to the invention comes in many variants.
• the shaped article may be made entirely of the thermoplastic synthetic material. It is also possible to apply a coating of the thermoplastic synthetic material onto a shaped article made of metal or a ceramic material.
• the granulate obtained in this way was injection moulded to black sheets at a temperature of 240°C with an ARBURG Allrounder® (320-90-750) injection shaped article machine.
• a part of the surface of the sheets was then irradiated with a leaser beam from an SHG Nd:YAG Q-switch laser, type Haas Laser® 6411 Engravity System (from Haas Laser, Germany).
• the pulse time was 110 nanoseconds, the wavelength was 532 nanometres, at a high radiation energy density (about 20 Joule/cm2).
• the marking obtained in this way had a white/grey colour.
• the abrasion resistance of this marking was tested by means of the device used in the Taber abraser test (ASTM D4060: 'Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser'). The abrasion resistance was qualified as 'good', 'reasonable' or 'poor'.
• the impact resistance of the marked material was measured in kJ/m2 according to DIN 51320 (Izod impact test, notched).
• Comparative experiment A was repeated, but now using 94.3 parts by weight of acrylonitrile-butadiene-styrene copolymer (Ronfalin® SFA-34, from DSM, of the Netherlands), 0.6 part by weight of carbon black (Black Pearls® 880, from CABOT, of the Netherlands) and 0.1 part by weight of titanium dioxide (Tiofine® R41, from TIOFINE, of the Netherlands), 2.5 parts by weight of PPG 2000 (polypropylene glycol 2000, from Hofag Chemical Corporation, of the USA) and 2.5 parts by weight of CAPA® 656 (from Interox Chemicals Ltd., of the UK).
• Ronfalin® SFA-34 acrylonitrile-butadiene-styrene copolymer
• carbon black Black Pearls® 880, from CABOT, of the Netherlands
• titanium dioxide Teofine® R41, from TIOFINE, of the Netherlands
• PPG 2000 polypropylene glycol 2000, from Hofag Chemical Corporation, of
• Example I was repeated, but now PPG 2000 and CAPA® 656 were replaced by 5 parts by weight of Perkadox® 30 (from AKZO Chemicals Division, of the Netherlands).
• Example II was repeated, but now Perkadox® 30 was replaced by 5 parts by weight of CP-FLAM® (from Nordmann Rassmann GmbH & Co., of Germany).
• Example II was repeated, but now Perkadox® 30 was replaced by 5 parts by weight of Spinflam® MF83 (from Himont, of Italy).
• Example II was repeated, but now Perkadox® 30 was replaced by 5 parts by weight of Ceepree® C-200 (from ICI Chemicals & Polymers Ltd., of the UK).
• Example II was repeated, but now Perkadox® 30 was replaced by 5 parts by weight of Ceepree® Microfine (from ICI Chemicals & Polymers Ltd., of the UK).
• Example II was repeated, but now Perkadox® 30 was replaced by 2 parts by weight of pentaerythritol (Qual. R., pulverized, from Degussa, of Germany) and 3 parts by weight of Exolyt® 422 (ammonium polyphosphate, from Hoechst Holland n.v., of the Netherlands).
• Example II was repeated, but now Perkadox® 30 was replaced by 2 parts by weight of Dures 22091 (novolac, from Occidental Chemical, of Belgium) and 3 parts by weight of Exolyt® 422 (ammonium polyphosphate, from Hoechst Holland n.v., of the Netherlands).
• Example II was repeated, but now Perkadox® 30 was replaced by 1 part by weight of Madurit® MW909 (cured melamine-formaldehyde resin, from Hoechst Holland n.v., of the Netherlands) and 94.3 parts by weight of ABS were replaced by 98.3 parts by weight of ABS.
• Madurit® MW909 cured melamine-formaldehyde resin, from Hoechst Holland n.v., of the Netherlands
• Example II was repeated, but now Perkadox® 30 was replaced by 3 parts by weight of Melamine Superfine®, D90 ⁇ 5 m ⁇ (from DSM, of the Netherlands) and 94.3 parts by weight of ABS were replaced by 96.3 parts by weight of ABS.
• Example II was repeated, but now Perkadox® 30 was replaced by 2 parts by weight of trishydroxyethyl isocyanurate (from BASF AG, of Germany) and 3 parts by weight of Exolyt® 422 (ammonium polyphosphate, from Hoechst Holland n.v., of the Netherlands).
• Example II was repeated, but now Perkadox® 30 was replaced by 3 parts by weight of Melamine Superfine®, D90 ⁇ 100 m ⁇ (from DSM, of the Netherlands) and 94.3 parts by weight of ABS were replaced by 96.3 parts by weight of ABS.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3888141

Family Applications (1)

Country Status (4)

Cited By (5)

Citations (5)

• 1994
  • 1994-05-04 BE BE9400464A patent/BE1008341A3/nl not_active IP Right Cessation
• 1995
  • 1995-05-03 EP EP95201142A patent/EP0680831B1/de not_active Expired - Lifetime
  • 1995-05-03 DE DE69503309T patent/DE69503309T2/de not_active Expired - Fee Related
  • 1995-05-03 AT AT95201142T patent/ATE168074T1/de not_active IP Right Cessation

Patent Citations (6)

Non-Patent Citations (1)

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