CA2294235A1 - Plastics which can be laser-marked - Google Patents
Plastics which can be laser-marked Download PDFInfo
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- CA2294235A1 CA2294235A1 CA002294235A CA2294235A CA2294235A1 CA 2294235 A1 CA2294235 A1 CA 2294235A1 CA 002294235 A CA002294235 A CA 002294235A CA 2294235 A CA2294235 A CA 2294235A CA 2294235 A1 CA2294235 A1 CA 2294235A1
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- Prior art keywords
- laser
- markable
- plastic
- plastics
- plastics according
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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
- B41M5/36—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties
- B41M5/366—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties using materials comprising a polymeric matrix containing a polymeric particulate material, e.g. hydrophobic heat coalescing particles
-
- 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
- B41M5/36—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties
-
- 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
Abstract
The invention relates to plastics which can be marked by laser, characterised in that an absorber material in the form of a plastic which is not receptive to laser treatment contains a polymer whose intrinsic properties are such that it can be marked by laser. Said polymer is present in the form of micro-ground particles with a particle size of between 0.1 and 100 µm.
Description
;'~E, PAN-FPI THIS Ai~9ED
THEfi-TRANSLATION
- Laser-markable plastics The present invention relates to laser-markable plastics of which a feature is that a plastic which is difficult to laser-treat comprises as absorber material one or more intrinsically laser-markable polymers in the form of micromilled particles having a particle size of 0.1 - 100 Vim.
The labelling of production goods is becoming increasingly important in almost all sectors of industry. For example, it is frequently necessary to apply production dates, expiry dates, barcodes, company logos, serial numbers, etc. At present, these marks are predominantly made using conventional techniques such as printing, embossing, stamping and labelling.
However, the importance of contactless, high-speed and flexible marking using lasers is increasing, especially in the case of plastics. This technique makes it possible to apply graphic inscriptions, for example barcodes, at high speed even on a non-planar surface.
Since the inscription is within the plastics article itself, it is durable and resistant to abrasion.
Many plastics, for example polyethylene (PE), polypropylene (PP), polyamide (PA), polymethyl meth acrylate (PMMA), polyoxymethylene (POM), polyurethane (PUR), polyesters have hitherto proved to be very difficult or even impossible to mark by means of the laser. A COZ laser which emits light in the infrared region at' 10.6 ~m produces only a faint, barely legible mark on polyolefins, even at very high output levels, since the absorpt~.on coefficient of the plastics to be processed is not high enough at these wavelengths to induce a colour change in the polymeric material. The plastic must not completely reflect or transmit the laser light, since if it did there would be no interaction. However, there must also not be strong absorption, since in that case the plastic evaporates.
to leave only an engraving. The absorption of the laser beams and hence the interaction with the material - depends on the chemical structure of the plastic and on the laser wavelength employed. In many cases it is necessary to add appropriate additives, for example absorbers, in order to render plastics laser s inscribable.
The article "Pearl Lustre Pigments -Characteristics and Functional Effects" in Speciality Chemicals, May 1982, Vol.2, No. 2 discloses the use of pearl lustre pigments for laser marking. Pearl lustre .10 pigments, however, have the disadvantage that they severely alter the colour properties of the plastic, an effect which is often unwanted.
DE-A 29 36 926 discloses that the inscription of a polymeric material by means of laser light can be 15 achieved by adding to the plastic a filler, such as carbon black or graphite, which discolours on exposure to energetic radiation.
EP 0 190 997 A prepares laser-inscribable moulding compounds, including PE, ~.~ or PS, by 20 adding at least one inorganic pigment to the high molecular mass organic material.
In EP 0 330 869, Ti02 and carbon black are added to PBT and PET. The inscription is dark on a light background. The use of carbon black and/or graphite as 25 absorbers in connection with the laser marking of polyesters is known from EP 0 485 181.
However, the fillers known for laser marking have the disadvantage either that they permanently colour the plastic that is to be inscribed, and hence 30 the laser inscription, which is usually a dark script on a lighter background, then lacks sufficient contrast, i . a . legibility, or that as in the case, for example, of kaolin the mark is very faint and becomes readily visible only when large amounts of the additive 35 are employed.
DE 195 36 047 describes the use of polycarbonate, which itself is difficult to laser-mark owing to its amorphous structure, in a polymer matrix of a polyalkylene terephthalate. Through absorption of laser energy it is possible for dark characters to be achieved on a light background in the polymer matrix of a polyalkylene terephthalate.
In addition to the abovementioned plastics, however, there are also polymers which can be marked by means of a laser with darkness and great contrast without the addition of additives. Examples of such polymers include PET, butadiene-styrene (ABS), polystyrene, polyphenyl ether (PPO), liquid crystal polymers (LCP), polyphenylene sulfide, polyarylates, 'polyaryl sulfides, polyaryl sulfones, polyaryl ether ketones, and blends thereof.
The object of the present invention, therefore, was to find laser-markable plastics which permit high contrast laser marking on exposure to laser light. In this context, the filler or successful absorber should have a very pale, neutral inherent colour and should possess the properties of the precoloured plastic that is to be marked or should have little or no effect on these properties.
It has surprisingly been found that a plastic which is difficult to laser-treat can be marked very effectively if, for example, one of the abovementioned intrinsically markable polymers is added in fine distribution to the plastic. The intrinsic markability of the polymer is thus transferred to the plastic which shows little if any such behaviour. Following laser bombardment, a plastic doped in this way shows high contrast'and crisply contoured markings even at low laser intensities.
The invention therefore provides laser-markable plastics, characterized in that plastics which are difficult to laser-treat comprise one or more intrinsically markable polymers having a particle size of from 0.1 to 100 Vim. .
Through the addition of micromilled, intrinsically markable polymers as absorbers in concentrations of 0.1 to loo by weight, preferably 0.1 to 5°s by weight and, in particular, 0.1 to 2% by - weight, based on the plastics system, a high contrast is obtained in connection with laser marking. The concentration of the intrinsically markable polymers in the plastic, however, is dependent on the plastics system employed and on the laser used.
Suitable polymers or polymer mixtures are all known readily laser-treatable plastics, such as PET, ABS, polystyrene, PPO, polyphenylene sulfide, polyphenylene sulfone, polyimidosulfone and LCPs, for example.
Micromilled thermoplastics having a very high melting range of >300°C are particularly suitable. The crispness of the contours of the mark is determined in particular by the particle size of the micromilled polymers. The polymers preferably have particle sizes in the range from 0.1 to 50 Vim, in particular from 1 to 2 0 ~.m .
The resulting mark is positively influenced if the intrinsically markable polymer comprises as further absorber, a light-sensitive pigment, such as a filler, for example, a conductive pigment and/or a special-effect pigment. The addition of a further absorber intensifies the contrast as a function of the plastics system used. The amount of light-sensitive pigment added should be between 0.1 and 90%
Particularly suitable light-sensitive pigments are fillers, such as Ti02 and Si02, for example, and phyllosilicates. Suitable silicatic platelets here are, in particular, light-coloured or white micas. It is of course also possible to use other natural micas, such as phlogopite and,biotite, synthetic mica, talc flakes and glass flakes. By special-effect pigments are meant all known lustre, metallic and pearl lustre~pigments, as marketed, for example, by the companies Mearl, Eckart-Werken and Merck KGaA. Examples of suitable conductive pigments are the pigments marketed under the tradename Minatec~ by Merck KGaA. These are platelet-shaped TiOz/ mica pigments comprising an external tin/antimony oxide layer as conductive coat. Other suitable light-sensitive pigments are the oxides, hydroxides, sulfides, sulfates and phosphates of metals such as copper, bismuth, tin, zinc, silver, antimony, manganese, iron, nickel and chromium, for example.
THEfi-TRANSLATION
- Laser-markable plastics The present invention relates to laser-markable plastics of which a feature is that a plastic which is difficult to laser-treat comprises as absorber material one or more intrinsically laser-markable polymers in the form of micromilled particles having a particle size of 0.1 - 100 Vim.
The labelling of production goods is becoming increasingly important in almost all sectors of industry. For example, it is frequently necessary to apply production dates, expiry dates, barcodes, company logos, serial numbers, etc. At present, these marks are predominantly made using conventional techniques such as printing, embossing, stamping and labelling.
However, the importance of contactless, high-speed and flexible marking using lasers is increasing, especially in the case of plastics. This technique makes it possible to apply graphic inscriptions, for example barcodes, at high speed even on a non-planar surface.
Since the inscription is within the plastics article itself, it is durable and resistant to abrasion.
Many plastics, for example polyethylene (PE), polypropylene (PP), polyamide (PA), polymethyl meth acrylate (PMMA), polyoxymethylene (POM), polyurethane (PUR), polyesters have hitherto proved to be very difficult or even impossible to mark by means of the laser. A COZ laser which emits light in the infrared region at' 10.6 ~m produces only a faint, barely legible mark on polyolefins, even at very high output levels, since the absorpt~.on coefficient of the plastics to be processed is not high enough at these wavelengths to induce a colour change in the polymeric material. The plastic must not completely reflect or transmit the laser light, since if it did there would be no interaction. However, there must also not be strong absorption, since in that case the plastic evaporates.
to leave only an engraving. The absorption of the laser beams and hence the interaction with the material - depends on the chemical structure of the plastic and on the laser wavelength employed. In many cases it is necessary to add appropriate additives, for example absorbers, in order to render plastics laser s inscribable.
The article "Pearl Lustre Pigments -Characteristics and Functional Effects" in Speciality Chemicals, May 1982, Vol.2, No. 2 discloses the use of pearl lustre pigments for laser marking. Pearl lustre .10 pigments, however, have the disadvantage that they severely alter the colour properties of the plastic, an effect which is often unwanted.
DE-A 29 36 926 discloses that the inscription of a polymeric material by means of laser light can be 15 achieved by adding to the plastic a filler, such as carbon black or graphite, which discolours on exposure to energetic radiation.
EP 0 190 997 A prepares laser-inscribable moulding compounds, including PE, ~.~ or PS, by 20 adding at least one inorganic pigment to the high molecular mass organic material.
In EP 0 330 869, Ti02 and carbon black are added to PBT and PET. The inscription is dark on a light background. The use of carbon black and/or graphite as 25 absorbers in connection with the laser marking of polyesters is known from EP 0 485 181.
However, the fillers known for laser marking have the disadvantage either that they permanently colour the plastic that is to be inscribed, and hence 30 the laser inscription, which is usually a dark script on a lighter background, then lacks sufficient contrast, i . a . legibility, or that as in the case, for example, of kaolin the mark is very faint and becomes readily visible only when large amounts of the additive 35 are employed.
DE 195 36 047 describes the use of polycarbonate, which itself is difficult to laser-mark owing to its amorphous structure, in a polymer matrix of a polyalkylene terephthalate. Through absorption of laser energy it is possible for dark characters to be achieved on a light background in the polymer matrix of a polyalkylene terephthalate.
In addition to the abovementioned plastics, however, there are also polymers which can be marked by means of a laser with darkness and great contrast without the addition of additives. Examples of such polymers include PET, butadiene-styrene (ABS), polystyrene, polyphenyl ether (PPO), liquid crystal polymers (LCP), polyphenylene sulfide, polyarylates, 'polyaryl sulfides, polyaryl sulfones, polyaryl ether ketones, and blends thereof.
The object of the present invention, therefore, was to find laser-markable plastics which permit high contrast laser marking on exposure to laser light. In this context, the filler or successful absorber should have a very pale, neutral inherent colour and should possess the properties of the precoloured plastic that is to be marked or should have little or no effect on these properties.
It has surprisingly been found that a plastic which is difficult to laser-treat can be marked very effectively if, for example, one of the abovementioned intrinsically markable polymers is added in fine distribution to the plastic. The intrinsic markability of the polymer is thus transferred to the plastic which shows little if any such behaviour. Following laser bombardment, a plastic doped in this way shows high contrast'and crisply contoured markings even at low laser intensities.
The invention therefore provides laser-markable plastics, characterized in that plastics which are difficult to laser-treat comprise one or more intrinsically markable polymers having a particle size of from 0.1 to 100 Vim. .
Through the addition of micromilled, intrinsically markable polymers as absorbers in concentrations of 0.1 to loo by weight, preferably 0.1 to 5°s by weight and, in particular, 0.1 to 2% by - weight, based on the plastics system, a high contrast is obtained in connection with laser marking. The concentration of the intrinsically markable polymers in the plastic, however, is dependent on the plastics system employed and on the laser used.
Suitable polymers or polymer mixtures are all known readily laser-treatable plastics, such as PET, ABS, polystyrene, PPO, polyphenylene sulfide, polyphenylene sulfone, polyimidosulfone and LCPs, for example.
Micromilled thermoplastics having a very high melting range of >300°C are particularly suitable. The crispness of the contours of the mark is determined in particular by the particle size of the micromilled polymers. The polymers preferably have particle sizes in the range from 0.1 to 50 Vim, in particular from 1 to 2 0 ~.m .
The resulting mark is positively influenced if the intrinsically markable polymer comprises as further absorber, a light-sensitive pigment, such as a filler, for example, a conductive pigment and/or a special-effect pigment. The addition of a further absorber intensifies the contrast as a function of the plastics system used. The amount of light-sensitive pigment added should be between 0.1 and 90%
Particularly suitable light-sensitive pigments are fillers, such as Ti02 and Si02, for example, and phyllosilicates. Suitable silicatic platelets here are, in particular, light-coloured or white micas. It is of course also possible to use other natural micas, such as phlogopite and,biotite, synthetic mica, talc flakes and glass flakes. By special-effect pigments are meant all known lustre, metallic and pearl lustre~pigments, as marketed, for example, by the companies Mearl, Eckart-Werken and Merck KGaA. Examples of suitable conductive pigments are the pigments marketed under the tradename Minatec~ by Merck KGaA. These are platelet-shaped TiOz/ mica pigments comprising an external tin/antimony oxide layer as conductive coat. Other suitable light-sensitive pigments are the oxides, hydroxides, sulfides, sulfates and phosphates of metals such as copper, bismuth, tin, zinc, silver, antimony, manganese, iron, nickel and chromium, for example.
5 Particular mention should be made in this case of the use of antimony, bismuth oxychloride and basic copper(II) hydroxide phosphate. Particular preference in this context is given to a product as formed by heating blue Cu ( I I ) orthophosphate ( Cu3 ( POQ ) 2~3 Hz0) by heating lto from 100 to 200°C, and which has the empirical chemical formula 4 CuO~PZO5~H20 or Cu, (PO,) 2~Cu (OH) 2. Other suitable copper phosphates are 6 CuO~PZ05~3 HzO, Cu3 (P04) z~3 Cu (OH) Z, 5 CuO~P205~3 H20, Cu3 (P04) y2 Cu (OH) Z~H20, 4 CuO~Pz05, 4 CuO~P205~3Hz0, 4 CuO~Pz05- 1.5 HzO, 4 Cu0-PZOS~ 1.2 H20.
An improvement in laser markability is also achieved if, in addition to the intrinsically marking polymer, one or more abovementioned light-sensitive pigments are added as a further component to the plastic. In this case the proportion by weight of all absorbers in the plastic, in combination with the micromilled polymers, should not exceed a total of l00 by weight, based on the plastics system. The plastic preferably contains 0-5% by weight of light-sensitive pigments, especially 0-to by weight. In this context, there is no restriction on the proportion in which the light-sensitive pigments are mixed with the micromilled polymers.
It is also possible to add, to the plastic that is difficult to laser-treat, colour pigments, which permit colour variations of any type and at the same time ensure that the laser marking is retained.
The light-sensitive pigments and/or colour pigments are added preferably together with the polymers, although separate addition is also possible in principle. A mixture of different light-sensitive pigments can also be added to the plastic.
Marking is preferably carried out using high-energy radiation, generally in the wavelength range from 150 nm to 10,600 nm, in particular in the range from 150 nm to 1100 nm. Mention may be made here, for example, of COz lasers (10,600 nm), Nd:YAG lasers (1064 nm or 532 nm) or pulsed UV lasers (excimer lasers). Particular preference is given to the use of Nd:YAG lasers (1064 nm and 532 nm) and COz lasers (10,600 nm). The energy densities of the lasers employed are generally in the range from 0.3 mJ/cmz to 50 J/cmz, preferably in the range from 0.3 mJ/cm~ to 10 J/cmz .
All known plastics which can only be laser-marked with great difficulty, as are described, for example, in Ullmann, Vol. 15, p. 457 ff., -, Verlag VCH or Saechtling Kunststoff Taschenbuch, can be employed for laser marking through addition of the polymers of the invention. Examples of such plastics are thermosets, polyethylene (PE-HD, PE-LD, PE-LLD), polypropylene (PP), polyesters, polyacetal, polyamides (PA), polyurethanes (PUR), polybutylene terephthalate, polymethyl methacrylate (PMMA), polyvinyl acetal, polystyrene, butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), and their copolymers and/or mixtures thereof. In particular, polyolefins, polyurethanes, polyoxymethylenes and polyamides, owing to their mechanical properties, the cost-effective processing methods and their poor laser-markability, are suitable for doping with the polymers of the invention.
The incorporation of the micromilled polymer into the plastic takes place by the techniques known for pigments and fillers. Subsequently, the pigmented plastic is then deformed under the action of heat. When choosing the intrinsically markable polymer to be milled it should be borne in mind that the particle structure is retained following the incorporation; in other words, the particles should not be soluble in the melt, and should not melt as well. This is achieved by appropriate tailoring of the melting ranges of the plastics system to that of the micromilled polymer.
An improvement in laser markability is also achieved if, in addition to the intrinsically marking polymer, one or more abovementioned light-sensitive pigments are added as a further component to the plastic. In this case the proportion by weight of all absorbers in the plastic, in combination with the micromilled polymers, should not exceed a total of l00 by weight, based on the plastics system. The plastic preferably contains 0-5% by weight of light-sensitive pigments, especially 0-to by weight. In this context, there is no restriction on the proportion in which the light-sensitive pigments are mixed with the micromilled polymers.
It is also possible to add, to the plastic that is difficult to laser-treat, colour pigments, which permit colour variations of any type and at the same time ensure that the laser marking is retained.
The light-sensitive pigments and/or colour pigments are added preferably together with the polymers, although separate addition is also possible in principle. A mixture of different light-sensitive pigments can also be added to the plastic.
Marking is preferably carried out using high-energy radiation, generally in the wavelength range from 150 nm to 10,600 nm, in particular in the range from 150 nm to 1100 nm. Mention may be made here, for example, of COz lasers (10,600 nm), Nd:YAG lasers (1064 nm or 532 nm) or pulsed UV lasers (excimer lasers). Particular preference is given to the use of Nd:YAG lasers (1064 nm and 532 nm) and COz lasers (10,600 nm). The energy densities of the lasers employed are generally in the range from 0.3 mJ/cmz to 50 J/cmz, preferably in the range from 0.3 mJ/cm~ to 10 J/cmz .
All known plastics which can only be laser-marked with great difficulty, as are described, for example, in Ullmann, Vol. 15, p. 457 ff., -, Verlag VCH or Saechtling Kunststoff Taschenbuch, can be employed for laser marking through addition of the polymers of the invention. Examples of such plastics are thermosets, polyethylene (PE-HD, PE-LD, PE-LLD), polypropylene (PP), polyesters, polyacetal, polyamides (PA), polyurethanes (PUR), polybutylene terephthalate, polymethyl methacrylate (PMMA), polyvinyl acetal, polystyrene, butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), and their copolymers and/or mixtures thereof. In particular, polyolefins, polyurethanes, polyoxymethylenes and polyamides, owing to their mechanical properties, the cost-effective processing methods and their poor laser-markability, are suitable for doping with the polymers of the invention.
The incorporation of the micromilled polymer into the plastic takes place by the techniques known for pigments and fillers. Subsequently, the pigmented plastic is then deformed under the action of heat. When choosing the intrinsically markable polymer to be milled it should be borne in mind that the particle structure is retained following the incorporation; in other words, the particles should not be soluble in the melt, and should not melt as well. This is achieved by appropriate tailoring of the melting ranges of the plastics system to that of the micromilled polymer.
7 _ When the micromilled polymer is incorporated into the plastics granules it is possible, if desired, to add coupling agents, organic, polymer-compatible solvents, stabilizers, optical brighteners, colour pigments, dyes, fillers, reinforcing agents, flameproofing additives, antistatics and/or surfactants which are temperature-stable under the operating conditions. In addition to the auxiliaries customarily employed it is possible to add further additives, not mentioned here, to the plastic. The presence of further 'additives in the existing plastics systems, however, may exert an effect on the marking result.
The plastics granule/polymer mixture is generally prepared by charging an appropriate mixer with the plastics granules, wetting them with any additives, and then adding the micromilled polymers and mixing them in. The mixture obtained in this way can then be processed directly in an extruder or an injection moulding machine. The mouldings formed in the course of processing usually exhibit a very homogeneous distribution of the polymers or of the polymer mixture.
Finally, laser marking takes place, preferably with a Nd:YAG laser.
Inscription with the laser is carried out by introducing the sample into the beam path of a pulsed laser, preferably a Nd:YAG laser. Inscription with a COZ
laser or an excimer laser is also possible. However, the desired results can also be achieved with other types ofwlaser featuring a wavelength in a range of high absorption by the intrinsically marking polymer.
The resulting shade and depth of colour are determined by the laser parameters, such as the irradiation time and irradiation output. The output of the lasers used depends on the particular application and can be determined regularly in each individual case by the skilled worker.
The plastic doped in accordance with the invention can be used in all sectors where customary printing processes have hitherto been employed for the inscription of plastics. For example, mouldings of the plastic of the invention can be employed in the electrical, electronic and motor vehicle industry. The labelling and inscription of, for example, housings, lines, keycaps, transcripts or functional parts in the heating, ventilation and cooling sectors, or switches, plugs, levers and handles which consist of the plastic of the invention, can be marked with the aid of laser light, even at difficult-to-reach points. Owing to its low heavy-metal content, the plastics system of the invention can also be employed in packaging in the foodstuffs sector or in the toy sector. The markings on packaging are notable for their resistance to wiping and scratching, for their stability during subsequent sterilization processes, and for the fact that they can be applied in a hygienically pure manner in the marking . process. Complete label motifs can be applied durably to the packaging for a reusable system. Another important area of application for laser inscription is that of identity cards and plastic tags for the individual identification of animals: so-called cattle tags or earmarks. The laser marking of plastics articles or mouldings which consist of the plastic of the invention is hence possible.
The examples which follow are intended to illustrate the invention without, however, restricting it.
Examples Example 1 _ g _ 99 parts of polypropylene (Stamylan PPH 10 from DSM) 1 part of polyphenylene sulfide milled to a particle size < 25 ~m The components are physically mixed and by means of an injection moulding machine are homogenized and shaped to form platelets. The inscription with a Nd:YAG laser at 532 and 1064 nm wavelengths shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 2 99.5 parts of polypropylene (Stamylan PPH 10) 0.5 part of polyphenylene sulfone milled to a particle size < 10 ~m The components are mixed and by means of an injection mou 'n machine are homogenized and shaped to form The inscription with a Nd:YAG ~~~~,~~
laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 3 99 parts of polyamide 6 (Ultramid B3K from BASF) 1 part of polyimidosulfone milled to a particle size 3 0 < 15 ~.m The components are mixed and by means of an injection moulding machine are homogenized and shaped to form platelets . The inscription with a Nd: YAG laser shows a high-contrast deep-black marking with a smooth surface over a wide range of settings.
Example 4 99.6 parts of polyamide 6 (Ultramid B3K) 0.4 part of polyphenylene sulfide milled to a particle size < 10 ~m The components are mixed and by means of an injection moulding machine are homogenized and shaped to form platelets. The inscription with a Nd:YAG laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 5 99 parts of polyoxymethylene (Delrin from Du Pont) 1 part of polyphenylene sulfide milled to a particle size < 5 ~m The components are mixed and by means of an injection mou~~~ machine are homogenized and shaped to form . The inscription with a Nd:YAG
laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 6 99 parts of unsaturated polyester resin (Palatal from BAS F ) 1 part of polyphenylene sulfide milled to a particle size < 10 ~.m The polyphenylene sulfide is incorporated homogeneously into the liquid polyester casting resin by stirring. Following the addition of accelerator (Co octoate) and hardener (cyclohexanone peroxide), the mixture is poured into a mould. After curing has taken place, a moulding is obtained which can be given a high-contrast black marking by means of Nd:YAG lasers.
Example 7 99 parts of polysulfone (Ultrason from BASF) are compounded on an extruder together with 1 part of mica. The compound is micromilled to a particle size of < 10 Vim. 0.50 of the powder thus obtained are added to a PMMA. This mixture is processed on an extruder to give sheets which can be given a black and high-contrast marking with a Nd:YAG laser at a wavelength of S32 and 1,064 nm.
Example 8 96 parts of polyphenylene sulfide are compounded by the method of Example 7 with 4 parts of basic copper phosphate. An addition of just 0.40 of the micromilled powder of this mixture to commonly non-laser-markable plastics, such as.
(a) polyethylene (PE) (b) polypropylene (PP) (c) olyamide (PA) (d) thyl methacrylate (PMMA) (e) polyurethane (PU) . (f) polyoxymethylene (POM) gives deep-black, high-contrast markings with crisp contours using a Nd:YAG laser.
The plastics granule/polymer mixture is generally prepared by charging an appropriate mixer with the plastics granules, wetting them with any additives, and then adding the micromilled polymers and mixing them in. The mixture obtained in this way can then be processed directly in an extruder or an injection moulding machine. The mouldings formed in the course of processing usually exhibit a very homogeneous distribution of the polymers or of the polymer mixture.
Finally, laser marking takes place, preferably with a Nd:YAG laser.
Inscription with the laser is carried out by introducing the sample into the beam path of a pulsed laser, preferably a Nd:YAG laser. Inscription with a COZ
laser or an excimer laser is also possible. However, the desired results can also be achieved with other types ofwlaser featuring a wavelength in a range of high absorption by the intrinsically marking polymer.
The resulting shade and depth of colour are determined by the laser parameters, such as the irradiation time and irradiation output. The output of the lasers used depends on the particular application and can be determined regularly in each individual case by the skilled worker.
The plastic doped in accordance with the invention can be used in all sectors where customary printing processes have hitherto been employed for the inscription of plastics. For example, mouldings of the plastic of the invention can be employed in the electrical, electronic and motor vehicle industry. The labelling and inscription of, for example, housings, lines, keycaps, transcripts or functional parts in the heating, ventilation and cooling sectors, or switches, plugs, levers and handles which consist of the plastic of the invention, can be marked with the aid of laser light, even at difficult-to-reach points. Owing to its low heavy-metal content, the plastics system of the invention can also be employed in packaging in the foodstuffs sector or in the toy sector. The markings on packaging are notable for their resistance to wiping and scratching, for their stability during subsequent sterilization processes, and for the fact that they can be applied in a hygienically pure manner in the marking . process. Complete label motifs can be applied durably to the packaging for a reusable system. Another important area of application for laser inscription is that of identity cards and plastic tags for the individual identification of animals: so-called cattle tags or earmarks. The laser marking of plastics articles or mouldings which consist of the plastic of the invention is hence possible.
The examples which follow are intended to illustrate the invention without, however, restricting it.
Examples Example 1 _ g _ 99 parts of polypropylene (Stamylan PPH 10 from DSM) 1 part of polyphenylene sulfide milled to a particle size < 25 ~m The components are physically mixed and by means of an injection moulding machine are homogenized and shaped to form platelets. The inscription with a Nd:YAG laser at 532 and 1064 nm wavelengths shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 2 99.5 parts of polypropylene (Stamylan PPH 10) 0.5 part of polyphenylene sulfone milled to a particle size < 10 ~m The components are mixed and by means of an injection mou 'n machine are homogenized and shaped to form The inscription with a Nd:YAG ~~~~,~~
laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 3 99 parts of polyamide 6 (Ultramid B3K from BASF) 1 part of polyimidosulfone milled to a particle size 3 0 < 15 ~.m The components are mixed and by means of an injection moulding machine are homogenized and shaped to form platelets . The inscription with a Nd: YAG laser shows a high-contrast deep-black marking with a smooth surface over a wide range of settings.
Example 4 99.6 parts of polyamide 6 (Ultramid B3K) 0.4 part of polyphenylene sulfide milled to a particle size < 10 ~m The components are mixed and by means of an injection moulding machine are homogenized and shaped to form platelets. The inscription with a Nd:YAG laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 5 99 parts of polyoxymethylene (Delrin from Du Pont) 1 part of polyphenylene sulfide milled to a particle size < 5 ~m The components are mixed and by means of an injection mou~~~ machine are homogenized and shaped to form . The inscription with a Nd:YAG
laser shows a high-contrast black marking with a smooth surface over a wide range of settings.
Example 6 99 parts of unsaturated polyester resin (Palatal from BAS F ) 1 part of polyphenylene sulfide milled to a particle size < 10 ~.m The polyphenylene sulfide is incorporated homogeneously into the liquid polyester casting resin by stirring. Following the addition of accelerator (Co octoate) and hardener (cyclohexanone peroxide), the mixture is poured into a mould. After curing has taken place, a moulding is obtained which can be given a high-contrast black marking by means of Nd:YAG lasers.
Example 7 99 parts of polysulfone (Ultrason from BASF) are compounded on an extruder together with 1 part of mica. The compound is micromilled to a particle size of < 10 Vim. 0.50 of the powder thus obtained are added to a PMMA. This mixture is processed on an extruder to give sheets which can be given a black and high-contrast marking with a Nd:YAG laser at a wavelength of S32 and 1,064 nm.
Example 8 96 parts of polyphenylene sulfide are compounded by the method of Example 7 with 4 parts of basic copper phosphate. An addition of just 0.40 of the micromilled powder of this mixture to commonly non-laser-markable plastics, such as.
(a) polyethylene (PE) (b) polypropylene (PP) (c) olyamide (PA) (d) thyl methacrylate (PMMA) (e) polyurethane (PU) . (f) polyoxymethylene (POM) gives deep-black, high-contrast markings with crisp contours using a Nd:YAG laser.
Claims (12)
1. Laser-markable plastics, characterized in that a plastic which is difficult to laser-mark comprises as absorber material an intrinsically laser-markable polymer in the form of micromilled particles having a particle size of 0.1 - 100 µm.
2. Laser-markable plastics according to Claim 1, characterized in that the absorber material is a high-temperature-resistant plastic.
3. Laser-markable plastics according to Claim 1 or 2, characterized in that the absorber material is polyphenylene sulfide, polysulfone, polyarylate, polyimide, liquid-crystalline polymers or a mixture thereof.
4. Laser-markable plastics according to one of Claims 1 to 3 , characterized in that the proportion of the absorber material based on the plastics system is 0.1 - 10% by weight.
5. Laser-markable plastics according to one of Claims 1 to 4, characterized in that the particle structure of the intrinsically markable polymer is retained in the plastic.
6. Laser-markable plastics according to one of Claims 1 to 5, characterized in that the absorber material additionally comprises, as further absorber, one or more light-sensitive pigments.
7. User-markable plastics according to Claim 6, characterized in that the light-sensitive pigment is natural or synthetic mica, copper phosphate, a special-effect pigment, a conductive pigment, a metal nitrate, metal sulfate, metal sulfide or metal oxide.
8. Laser-markable plastics according to one of Claims 1 to 7, characterized in that the proportion of the light-sensitive pigments in the plastic is from 0 to 5% by weight, based on the plastics system.
9. Laser-markable plastics according to one of Claims 1 to 8, characterized in that the plastic which is difficult to laser-treat is polyethylene, polypropylene, polyamide, polyoxymethylene, polyester, polymethyl methacrylate, polyurethane or a copolymer thereof.
10. Laser-markable plastics according to one of Claims 1 to 9, characterized in that they additionally comprise colour pigments.
11. Use of the laser-markable plastics according to Claim 1 as material for producing mouldings which are marked with the aid of lasers.
12. Mouldings consisting of the laser-markable plastic according to Claim 1.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19726136.1 | 1997-06-19 | ||
| DE19726136A DE19726136A1 (en) | 1997-06-19 | 1997-06-19 | Laser-markable plastics |
| PCT/EP1998/003250 WO1998058805A1 (en) | 1997-06-19 | 1998-05-30 | Plastics which can be laser-marked |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2294235A1 true CA2294235A1 (en) | 1998-12-30 |
Family
ID=7833076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002294235A Abandoned CA2294235A1 (en) | 1997-06-19 | 1998-05-30 | Plastics which can be laser-marked |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0991523B1 (en) |
| JP (1) | JP2002504947A (en) |
| KR (1) | KR20010013893A (en) |
| CN (1) | CN1169677C (en) |
| AU (1) | AU7917898A (en) |
| BR (1) | BR9810065A (en) |
| CA (1) | CA2294235A1 (en) |
| DE (3) | DE19726136A1 (en) |
| ES (1) | ES2183381T3 (en) |
| TW (1) | TW589339B (en) |
| WO (1) | WO1998058805A1 (en) |
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| US8318262B2 (en) | 2006-12-22 | 2012-11-27 | Eckart Gmbh | Use of spherical metal particles as laser-marking or laser-weldability agents, and laser-markable and/or laser-weldable plastic |
| US8691493B2 (en) | 2009-07-17 | 2014-04-08 | Leonhard Kurz & Stiftung & Co. KG | Method for the production of a multilayer element, and multilayer element |
| US8877332B2 (en) | 2007-11-30 | 2014-11-04 | Eckart Gmbh | Use of a mixture comprising spherical metal particles and metal flakes as laser-marking or laser-weldability agents and laser markable and/or laser weldable plastic |
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| DE10053639B4 (en) * | 2000-10-28 | 2007-04-12 | Chemische Fabrik Budenheim Kg | Use of iron, cobalt, nickel or molybdenum salts |
| DE10118178C2 (en) * | 2001-04-11 | 2003-05-08 | Draexlmaier Lisa Gmbh | Composite trim and process for its manufacture |
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| NZ539926A (en) * | 2002-12-04 | 2007-05-31 | Dsm Ip Assets B | Laser light absorbing additive |
| NL1022081C2 (en) * | 2002-12-04 | 2004-06-07 | Dsm Nv | Composition useful as a laser writable composition for marking purposes comprises a polymeric laser light absorber dispersed in a matrix polymer and a reflector |
| EP1431050A3 (en) * | 2002-12-19 | 2004-11-03 | MERCK PATENT GmbH | Process for laser marking of a liquid crystal film |
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| DE102004050479A1 (en) | 2004-10-15 | 2006-04-27 | Chemische Fabrik Budenheim Kg | Molding composition for the production of flame-retardant articles, pigment therefor and its use |
| DE102004050571A1 (en) * | 2004-10-15 | 2006-04-20 | Ticona Gmbh | Laser-markable molding material, useful e.g. to prepare shaped parts, comprises partial-crystalline thermoplast, an individual light sensitive salt-like compound or its mixture and optionally conventional additives |
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| WO2006065611A1 (en) * | 2004-12-14 | 2006-06-22 | Polyone Corporation | Use of bismuth oxides for laser markings in thermoplastic polyurethane compounds |
| JP2007306944A (en) * | 2005-01-21 | 2007-11-29 | Olympus Corp | Endoscope, medical appliance for endoscope, and method for display thereof |
| US20090306262A1 (en) * | 2005-08-18 | 2009-12-10 | Morio Tsunoda | Polyamide Resin Composition for Laser Marking and Laser-Marked Polyamide Resin Molded Product |
| DK1790701T4 (en) * | 2005-11-25 | 2012-04-02 | Sicpa Holding Sa | IR-absorbing deep-ink color |
| DE102006005089B4 (en) * | 2006-02-04 | 2015-04-16 | Preh Gmbh | operating element |
| DE102006038043A1 (en) | 2006-08-14 | 2008-02-21 | Chemische Fabrik Budenheim Kg | Laser inscribable polymer material |
| DE102006045495A1 (en) * | 2006-09-27 | 2008-04-03 | Mitsubishi Polyester Film Gmbh | Laser markable film |
| WO2008138362A1 (en) * | 2007-05-09 | 2008-11-20 | Actega Ds Gmbh | Use of spherical metal particles as laser marking additives for sealing, closure or coating materials or paints comprising polymer, and also laser-markable sealing, closure or coating material or laser-markable paint comprising polymer |
| DE102007050363A1 (en) * | 2007-10-15 | 2009-04-16 | Forschungsinstitut für Pigmente und Lacke e.V. | Method for laser marking a polymer material |
| DE102008005862A1 (en) * | 2008-01-15 | 2009-07-16 | IKT Institut für Kunststofftechnik | Laser-markable polymer material and process for its preparation |
| DE102008034022A1 (en) | 2008-07-16 | 2010-01-21 | Merck Patent Gmbh | Method for producing a security and / or value product with subregions with different luminescence emission |
| DE102008034021A1 (en) | 2008-07-16 | 2010-01-21 | Merck Patent Gmbh | Method for producing a security and / or value product with random pattern and correlated identity string |
| DE102009001335A1 (en) * | 2009-03-04 | 2010-09-09 | Chemische Fabrik Budenheim Kg | Radiation absorbing material |
| CN101927626B (en) * | 2009-06-18 | 2013-08-07 | 河南天海电器有限公司 | Master batch with function of plastic laser marking |
| DE102011088564A1 (en) | 2011-12-14 | 2013-06-20 | Robert Bosch Gmbh | Method for producing a labeled battery cell housing |
| CN103247462B (en) * | 2012-02-08 | 2015-06-24 | 联想(北京)有限公司 | Key cap and manufacturing method thereof, key board with key cap, and laptop |
| DE102013100252A1 (en) | 2013-01-11 | 2014-07-17 | Kuraray Europe Gmbh | Use of a mixture comprising a polyvinyl acetal and a laser absorber as laser marking agent for laser-markable polymers e.g. polyethylene, polypropylene, polyesters, polyamide, polyurethane or polybutylene |
| DE102014008962A1 (en) * | 2014-06-23 | 2016-01-07 | Merck Patent Gmbh | microspheres |
| DE102016210160A1 (en) | 2016-06-08 | 2017-12-14 | Weilburger Coatings Gmbh | Aqueous composition for producing a laser-markable coating and laser-marked coating |
| DE102016219858A1 (en) | 2016-10-12 | 2018-04-12 | Weilburger Coatings Gmbh | A method of making a coating having markings on a surface or part of a surface of an article |
| TWI666670B (en) * | 2018-05-18 | 2019-07-21 | 致伸科技股份有限公司 | Keycap structure and manufacturing method thereof |
| CN110628112A (en) * | 2019-09-28 | 2019-12-31 | 珠海市恒誉科技有限公司 | Polymer local induced blackening auxiliary agent and preparation method thereof |
| WO2024022990A1 (en) | 2022-07-26 | 2024-02-01 | Merck Patent Gmbh | Polymer composition for laser marking |
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|---|---|---|---|---|
| GB8825860D0 (en) * | 1988-11-04 | 1988-12-07 | Bicc Plc | Fluorocarbon polymer compositions & electric cables |
| DE4416129A1 (en) * | 1994-05-06 | 1995-11-09 | Basf Ag | Thermoplastic molding compounds with good labeling properties |
-
1997
- 1997-06-19 DE DE19726136A patent/DE19726136A1/en not_active Withdrawn
-
1998
- 1998-05-30 EP EP98929407A patent/EP0991523B1/en not_active Expired - Lifetime
- 1998-05-30 ES ES98929407T patent/ES2183381T3/en not_active Expired - Lifetime
- 1998-05-30 DE DE59805984T patent/DE59805984D1/en not_active Expired - Fee Related
- 1998-05-30 CA CA002294235A patent/CA2294235A1/en not_active Abandoned
- 1998-05-30 DE DE19880779T patent/DE19880779D2/en not_active Expired - Fee Related
- 1998-05-30 WO PCT/EP1998/003250 patent/WO1998058805A1/en not_active Application Discontinuation
- 1998-05-30 AU AU79178/98A patent/AU7917898A/en not_active Abandoned
- 1998-05-30 JP JP50364999A patent/JP2002504947A/en active Pending
- 1998-05-30 KR KR1019997011915A patent/KR20010013893A/en not_active Application Discontinuation
- 1998-05-30 CN CNB988062437A patent/CN1169677C/en not_active Expired - Fee Related
- 1998-05-30 BR BR9810065-3A patent/BR9810065A/en unknown
- 1998-06-16 TW TW087109560A patent/TW589339B/en not_active IP Right Cessation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8318262B2 (en) | 2006-12-22 | 2012-11-27 | Eckart Gmbh | Use of spherical metal particles as laser-marking or laser-weldability agents, and laser-markable and/or laser-weldable plastic |
| US8877332B2 (en) | 2007-11-30 | 2014-11-04 | Eckart Gmbh | Use of a mixture comprising spherical metal particles and metal flakes as laser-marking or laser-weldability agents and laser markable and/or laser weldable plastic |
| US8691493B2 (en) | 2009-07-17 | 2014-04-08 | Leonhard Kurz & Stiftung & Co. KG | Method for the production of a multilayer element, and multilayer element |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1260752A (en) | 2000-07-19 |
| WO1998058805A1 (en) | 1998-12-30 |
| AU7917898A (en) | 1999-01-04 |
| KR20010013893A (en) | 2001-02-26 |
| DE19726136A1 (en) | 1998-12-24 |
| JP2002504947A (en) | 2002-02-12 |
| EP0991523B1 (en) | 2002-10-16 |
| EP0991523A1 (en) | 2000-04-12 |
| ES2183381T3 (en) | 2003-03-16 |
| DE59805984D1 (en) | 2002-11-21 |
| BR9810065A (en) | 2000-09-19 |
| TW589339B (en) | 2004-06-01 |
| DE19880779D2 (en) | 2000-09-07 |
| CN1169677C (en) | 2004-10-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |