Method for marking a plastic object for laboratory use and a plastic object for laboratory use comprising a mark - Patents.com

Abstract

The present invention relates to a method for marking plastic objects for laboratory use, the method comprising using a laser light to create a dark contrast surface on the plastic of the object and using the laser light to create a light inscription on the dark contrast surface, or using a laser light to create a light contrast surface on the plastic of the object and using the laser light to create a dark inscription on the light contrast surface.

Description

[Technical Field]

[0001] The present invention relates to a method for marking plastic objects for laboratory use and to plastic objects for laboratory use, the objects being provided with a mark.

[0002] Biological, chemical, biochemical, medical, forensic, and other laboratories use trays and racks to hold pipette tips and containers, among other items: microplates, slides, cuvettes, cell culture vessels, reaction vessels, pipette tips, or containers. These are preferably single-use, meaning they are used only once, to prevent carryover between different samples. However, reusable labware, such as trays and racks, are also available, and pipette tips and containers can be refilled from refill packs.

[0003] Barcodes are being used more and more frequently to clearly label objects (labware) used in laboratories, allowing them to be reliably tracked and assigned using batch or serial numbers.

[0004] In many cases, laser marking is suitable for applying barcodes to plastic objects (barcoding) since no geometric or material changes to the object are required and the investment costs are reasonable.

[0005] When a laser beam is used to mark an object, it typically creates an optical contrast on the object so that the image of the laser-engraved barcode can be read by a camera.

[0006] In this case, it is usually necessary to distinguish between two different cases: the laser light changes the color to a lighter color, which provides good contrast for dark objects (especially black, blue, and dark green), and therefore for light objects, it is better to change the color to a darker color.

[0007] It has been shown that it is difficult to obtain readable contrast on certain colored objects, particularly light and medium grays, various shades of yellow, reds, and light greens. In these cases, the color change after laser irradiation is not strong enough for the camera to detect a clear color difference.

[0008] U.S. Patent No. 6,372,293 describes a test tube with an open top and a machine-readable code on the flat underside of the bottom. The code is manufactured on the outside of the bottom using a multi-layer coating. The multi-layer coating includes a first layer of opaque material deposited on the underside of the bottom and a second layer of opaque material deposited on the first layer. The machine-readable code is formed by removing a portion of the second layer using a laser beam. Damage to the coating has the disadvantage of rendering the label illegible. Furthermore, because the code is applied to the underside, it can be more difficult to read. Furthermore, manufacturing is complicated because the multi-layer coating must be applied before labeling.

[0009] International Patent Publication No. 2010 / 023102A1 describes a sample tube for biochemical and biological research and clinical diagnostics, which has an identification feature on the underside of its flat bottom. It consists of an opaque material with a first color and a transparent coating layer with a laser-sensitive filler. When irradiated with a laser writing beam, the irradiated surface of the transparent coating layer changes to an opaque surface with a second color that contrasts with the first color. This sample tube also suffers from the drawbacks associated with multilayer coatings for laser marking.

[0010] International Patent Publication No. 2011 / 135398A1 describes marking transparent containers, such as syringe bodies and pharmaceutical containers, in which dye spots are applied to the outside of the transparent wall, which is heated, and a data matrix is ​​engraved into the dye spots using laser light. This aims to mark the container without impairing the mechanical properties, such as the impact resistance, of the transparent wall of the container. However, this transparent container also suffers from the above-mentioned disadvantages associated with additional coatings.

[0011] European Patent No. 2805770B1 describes a laboratory container having a body coated with an opaque layer, which has recesses in the form of machine-readable data. The body has at least one localized material change that, together with the opaque layer, forms a read area where the machine-readable data can be read from the outside with an optical reader due to the optical contrast between the material change and the opaque layer. The recesses in the material change in the opaque layer and / or body are particularly created using a laser. Applying the machine-readable data directly to the body or within the body, respectively, provides a highly reliable labeling that cannot be removed from the body. Even in the case of this container, damage to the opaque layer can impair the readability of the data. Additionally, applying the opaque layer increases manufacturing efforts.

[0012] European Patent No. 2870998B1 describes a sample tube for chemical and biological testing that is integrally formed from a homogeneous, optically transparent material. This material is made from a homogeneous blend of a base polymer from the metallocene polyolefin family and a polypropylene-based masterbatch containing a laser-sensitive additive, which changes color to black-brown or another contrasting color upon excitation with a laser marker. A drawback is that the laser-sensitive additive can contaminate the contained sample. Furthermore, the use of a special plastic blend increases the manufacturing effort.

[0013] EP 3003536B1 describes a sample tube comprising a body made from a first component and a writable area made from a second component. The sample tube is manufactured integrally from the first and second components by a multi-component injection molding process. The first and second components contain the same polymer as the main component, and the second component contains an additive and can be written by laser irradiation. The complex manufacturing process using multiple components, one of which contains an additive, is disadvantageous because it can contaminate the sample.

[0014] Therefore, the object of the present invention is to provide a method for marking plastic objects for laboratory use, and to produce plastic objects for laboratory use that are easily readable and protected from damage, and that also provide good visibility, especially when the object is light or medium gray, shades of yellow, red or light green in color.

[0015] This object is achieved by a method according to claim 1. Furthermore, this object is achieved by the object according to claim 14. Advantageous embodiments of the method and object are specified in the dependent claims and the following description.

[0016] In a method according to the present invention for marking plastic objects for laboratory use, a laser beam is used to create a dark contrasting surface on the plastic portion of the object and a light writing on the dark contrasting surface, or alternatively, a laser beam is used to create a light contrasting surface on the plastic portion of the object and a dark writing on the light contrasting surface.

[0017] A plastic object for laboratory use according to the present invention has a marking comprising a dark contrasting surface and a light inscription on the dark contrasting surface, or a light contrasting surface and a dark inscription on the light contrasting surface, the dark areas being carbonized areas of the plastic part of the object and the light areas being micro-foamed areas of the plastic part of the object.

[0018] According to the present invention, the contrast and therefore legibility of the mark are improved by using laser light to create a contrasting surface and an inscription on the contrasting surface. Either the contrasting surface is dark and the inscription is light, or the contrasting surface is light and the inscription is dark. This is achieved by using laser light to carbonize the plastic in the dark areas and micro-bubble the plastic in the light areas. During carbonization, the polymer in the plastic carbonizes and turns black, respectively. During micro-bubble formation, the thermal effect of the laser irradiation forms bubbles in the plastic, causing the plastic to swell to a light color or a whitish color, respectively. According to the present invention, marks with enhanced contrast and improved legibility can be applied to objects made of plastics of any color, and even colorless plastics.

[0019] Preferably, objects made of plastics of colors that could not previously be marked with good contrast, in particular light to medium gray, yellow, red or light green plastics, are marked according to the invention. However, the invention is also suitable for making more legible markings on plastic objects that can already be marked well, for example in the case of white, dark green, blue or black plastics.

[0020] Because the mark is formed into the plastic of the target, there is no need to apply a coating or separate marking carrier, eliminating the risk of the mark becoming illegible due to the marking carrier peeling off or becoming damaged, and eliminating the manufacturing effort associated with applying a marking carrier.

[0021] According to the present invention, it is possible to mark an object at any freely selectable position during the manufacturing process at high speed. The position of the mark on the object can be selected in particular with a view to readability in mind. The mark can be placed in particular on the side of the object, which can be easily photographed by a camera during use.

[0022] The marking can be produced in the plastic part of the object without the addition of additives, thus avoiding contamination of the sample due to contact with additives. The strength and other mechanical properties of the object are not impaired by the marking, or are impaired only to a negligible extent.

[0023] No additional materials are required to produce the mark and no waste is generated. The mark is particularly resistant to damage caused by mechanical or chemical influences, heat, cold and light.

[0024] The mark is applied to the object so that it can be photographed from the outside using a camera or other reading device, or visually. For this purpose, in the case of an object made of opaque plastic, the mark is preferably applied to the outer surface of the object. In particular, in the case of an object made of a transparent or more or less light-transmitting material, the mark can also be located on the outer surface, between the inner and outer surfaces, or on the inner surface. The focus of the laser light during marking can be set appropriately to the position of the desired mark.

[0025] According to one embodiment of the method, the contrast surface is created in the plastic part by leaving free areas in the inscription, and the inscription is created only in the areas that have been left free, or the inscription is created in the plastic part, and the contrast surface is created in the plastic only next to the inscription, which allows a particularly strong contrast to be achieved and minimizes changes in the plastic part.

[0026] According to another embodiment, a contrasting surface is created in the plastic material and partially overlaid by the inscription, or the inscription is created in the plastic material and the contrasting surface is partially created on top of the inscription. Surprisingly, it has been shown that the contrast of the marking is improved even when the colored surfaces are superimposed on each other using laser light. Clearly, the dark areas resulting from the carbonized polymer are also more clearly visible than the light areas in the microcellular regions.

[0027] According to another embodiment, the inscription and the contrast surface are produced using the same laser, and one or more parameters of the laser's laser writing are modified to produce the contrast surface and the inscription. Using the same laser for the contrast surface and the inscription is advantageous for accurately aligning the contrast surface and the inscription with each other. In addition, less equipment is required.

[0028] In another embodiment, the inscription and the contrast surface are produced using different lasers. Using different lasers allows the contrast surface and the inscription to be produced simultaneously, thereby increasing production speed. When using different lasers to mark an object, it is possible to use different types of lasers that are particularly suited to coloring the light and dark areas, respectively, in order to create a particularly strong contrast.

[0029] According to another embodiment, at least one of the following laser parameters is set for generating the inscriptions and / or contrast surfaces: laser power, pulse speed, scan speed, track width, focus, or color. This allows the same laser to be used to generate the contrast surface and the inscriptions, and the parameter settings can be changed in both cases to generate the contrast surface and the inscriptions. However, the ability to set the parameters can also be used in both cases to permanently set different lasers to generate the contrast surface with one laser and the marks with another laser.

[0030] According to another embodiment, the laser is a marking laser.

[0031] According to another embodiment, the at least one laser is selected from the group of lasers: CO2 marking lasers, YVO4 marking lasers, fiber marking lasers, SHG marking lasers. Preferably, the laser is a YVO4 marking laser or a CO2 marking laser, since these laser types are highly suitable for producing a color change in the plastic part.

[0032] According to another embodiment of the method, the object is provided with a marking by the manufacturer of the object. According to another embodiment, the object is provided with a marking by a user of the object, for example a filler who fills the object with a reagent, an active substance composition, etc., or a user of the object in a laboratory who uses the object to test a sample. The marking can be used in particular by the user to identify the reagent, active substance composition, or sample contained therein.

[0033] In one embodiment of the method and object, the plastic part has a light to medium gray, yellow, red, or light green color. As previously explained, legible markings on plastics of these colors can be difficult, and the present invention significantly improves legibility.

[0034] According to another embodiment of the method and object, the plastic portion includes at least one additive that produces a stronger color change upon laser irradiation. This embodiment is particularly contemplated when the plastic object or part of the object does not come into contact with the sample or when the additive is inert to the sample.

[0035] According to another embodiment of the invention and the object, the inscription is a barcode and / or a two-dimensional (2D) code. According to another embodiment, the 2D code is a data matrix code or a QR code.

[0036] According to another embodiment of the method and object, at least one plastic of the object is selected from the following group of plastics: polypropylene, polyethylene, polycarbonate, polystyrene, and styrene polymers such as ABS. The object can consist of only one of the aforementioned plastics or of several of the aforementioned plastics. The plastics can be connected to one another, in particular in a multi-component injection molding process. The object can be a single part or have several parts.

[0037] According to another embodiment of the method and object, the object comprises a plurality of marks spaced apart from one another, each consisting of a contrasting surface and an inscription portion, or alternatively, the object has a plurality of marks spaced apart from one another, each consisting of a contrasting surface and an inscription portion.

[0038] The invention will be explained in more detail below on the basis of the accompanying drawings of exemplary embodiments. [Brief explanation of the drawings]

[0039] [Figure 1] 1 shows a top and side view of a microplate according to the invention with two colored marks. [Figure 2] Enlarged front view showing the marks on the microplate. [Figure 3] 1 is a schematic block diagram of mark generation using a laser. [Figure 4a-c] 4a) a conventional single-color mark; FIG. 4b) a two-color mark according to the present invention having a light-colored marking on a dark contrasting surface; and FIG. 4c) a two-color mark according to the present invention having a dark-colored marking on a light-colored contrasting surface.

[0040] As shown in FIG. 1, the microplate 1 comprises a frame 2 having a generally rectangular flat plate 3 and four side walls 4, 5, 6, and 7 extending vertically downward from the four side edges of the plate 3, which together form a shell 8.

[0041] The shell 8 has a circumferential widening 9 at the bottom, which is designed to accommodate the upper edge of a microplate 1 of the same design in order to stack multiple microplates.

[0042] A number of tubular containers 10 are connected to the plate 3. Each of the containers 10 has an upper edge connected to the plate 3. In the surface of the plate 3, there is an opening 11 accessible from above. Furthermore, each of the containers has a tubular holder 12 that protrudes downward from below the plate 3 and is closed at the bottom by a base.

[0043] 1 shows an embodiment of a microplate 1 in which the reservoir 10 is particularly deep and the shell 8 is particularly tall. This embodiment is also called a "deep well plate".

[0044] The vessel openings 11 are arranged in 8 rows and 12 columns in the plate 3, for a total of 96 vessels 10. The microplate 1 is standardized according to ANSI / SBS Standard 1-2004.

[0045] The microplate 1 is manufactured in one piece from plastic (such as polypropylene). The plastic is yellow.

[0046] 1 and 2, a mark 13 comprising a Data Matrix code 14 and an alphanumeric product identifier 15 is arranged on the outside of the side wall 4. The mark 13 has a light contrasting surface 16 and a dark inscription 17 within the contrasting surface 16, the dark inscription 17 comprising the Data Matrix code 14 and the alphanumeric product identifier 15.

[0047] Within the contrast area 16, the yellow plastic of the microtiter plate 1 changes color from yellow to a light color (such as light green). Within the writing area 17, the plastic of the microtiter plate 1 changes color from yellow to a dark color or black, respectively.

[0048] Figure 3 shows a schematic diagram of a method for marking the microplate 1 of Figure 1 or another object. In a first step 18, the laser is applied or, respectively, the laser parameters are set so that the laser beam changes the color of the object from a predetermined base color (e.g., yellow) to as light a gray as possible. In this process, the laser usually has a higher marking intensity than when producing dark markings.

[0049] According to a second step 19, bright contrast areas are marked in such a way that the laser light of the laser thus set or thus supplied illuminates the areas of the object where contrast surfaces 16 are to be formed. In this step, the areas where the inscriptions 17 are to be generated are preferably left free.

[0050] In a third step 20, the laser is supplied or the laser parameters are set so that the laser light irradiates the object, changing its color from the base color to as dark a gray as possible. In this step, the laser marking intensity is usually lower than when producing a light-colored contrast surface.

[0051] In a fourth step 21, with the aid of the thus provided or respectively set laser, inscriptions 17 are produced in the previously unoccupied areas of the contrast surface 16. During this process, the color of the object changes from the light base color to the dark inscriptions 17, thus completing the mark 13 shown in Figures 1 and 2.

[0052] According to FIG. 4a, the dark shape marking 17 produced in a conventional manner on a yellow plastic object using laser light is not legible or only poorly legible.

[0053] According to FIG. 4b, a two-color mark introduced according to the invention into a yellow plastic object using laser light has a light-colored inscription 17 within a dark contrasting surface 16, but has good contrast and is easily readable.

[0054] According to FIG. 4b, a two-color mark introduced according to the invention into a yellow plastic object using laser light also has a dark marking 17 within a light contrasting surface 16, but has good contrast and is easily readable.

[0055] For polypropylene microplates with the product designation Deep Well Plate in yellow (RAL 1026), marks with good contrast are generated with the help of a CO2 marking laser type laser with the following setting parameters:

[0056] To fabricate a bright surface, the laser parameters are set as follows: pulse frequency 38 kHz, scan speed 1,360 mm / s, track width 0.02 mm.

[0057] To fabricate the dark surface, the laser parameters are set as follows: pulse frequency 46 kHz, scan speed 2,500 mm / s, track width 0.06 mm.

Claims

1. A method for marking plastic objects for laboratory use, comprising using a laser light to create a dark contrasting surface on the plastic of the object and using a laser light to create a light marking on the dark contrasting surface, or using a laser light to create a light contrasting surface on the plastic of the object and using a laser light to create a dark marking on the light contrasting surface.

2. 2. The method of claim 1, wherein the contrast surface is created in the plastic part by leaving a free area in the inscription, and the inscription is created only in the area that left the free area, or the inscription is created in the plastic part and the contrast surface is created only next to the inscription in the plastic part.

3. 2. The method of claim 1, wherein the contrast surface is generated in the plastic part and is partially overwritten by the inscription, or the inscription is generated in a plastic material and the contrast surface is partially generated over the inscription in the plastic material.

4. 4. The method according to claim 1, wherein the inscription and the contrast surface are generated using the same laser, and one or more parameters of the laser marking of the laser are altered to generate the contrast surface and the inscription.

5. 5. The method according to claim 1, wherein the inscription and the contrast surface are generated by means of different lasers.

6. The method according to claim 4 or 5, wherein at least one of the following parameters of the laser is set for generating the inscription and / or the contrast surface: laser power, pulse speed, scan speed, track width, focus or color.

7. The method according to claim 1 , wherein the laser is a marking laser.

8. 8. The method according to claim 1 , wherein at least one laser is selected from the following group of lasers: ２ Marking laser, YVO ４ Marking laser, fiber marking laser, SHG marking laser.

9. 9. The method according to claim 1, wherein the plastic part has a light to medium grey colour, yellow, red or light green.

10. 10. The method according to claim 1, wherein the plastic part comprises at least one additive, which brings about a stronger color change upon laser irradiation.

11. The method according to claim 1 , wherein the inscription is a bar code and / or a two-dimensional (2D) code.

12. The method according to one of claims 1 to 11, wherein at least one plastic of the object is selected from the following group of plastics: polypropylene, polyethylene, polycarbonate, polystyrene or styrene polymers such as ABS.

13. 13. The method according to claim 1, wherein the object for laboratory use is a tray or rack for holding pipette tips or vessels, a microplate, a slide, a cuvette, a cell culture vessel, a reaction vessel, or a pipette tip.

14. 1. A plastic object for laboratory use, comprising a marking having a dark contrasting surface and a light marking on the dark contrasting surface, or a light contrasting surface and a dark marking on the light contrasting surface, the dark areas being carbonized areas of the plastic part of the object and the light areas being micro-foamed areas of the plastic part of the object.

15. 15. The object of claim 14, which is a tray or rack for holding pipette tips or vessels, a microplate, a slide, a cuvette, a cell culture vessel, a reaction vessel, or a pipette tip.

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