Classifications

• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
  • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
  • G09F3/02—Forms or constructions
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65C—LABELLING OR TAGGING MACHINES, APPARATUS, OR PROCESSES
  • B65C3/00—Labelling other than flat surfaces
  • B65C3/06—Affixing labels to short rigid containers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65C—LABELLING OR TAGGING MACHINES, APPARATUS, OR PROCESSES
  • B65C9/00—Details of labelling machines or apparatus
  • B65C9/46—Applying date marks, code marks, or the like, to the label during labelling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D23/00—Details of bottles or jars not otherwise provided for
  • B65D23/08—Coverings or external coatings
  • B65D23/0842—Sheets or tubes applied around the bottle with or without subsequent folding operations
  • B65D23/085—Sheets or tubes applied around the bottle with or without subsequent folding operations and glued or otherwise sealed to the bottle
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
  • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
  • G09F3/02—Forms or constructions
  • G09F2003/0201—Label sheets intended to be introduced in a printer, e.g. laser printer

Definitions

• the present invention relates to flexible, plastic labels for use on flexible plastic bottles, which labels are both ink printable and laser-markable.
• plastic labels for squeezable, flexible plastic bottles have been made from paper coated with pressure sensitive adhesives. More recently, plastics have replaced paper to a large extent for this purpose. Plastic labels tend to exhibit a higher degree of flexibility, squeezability and a greater resistance to water and other chemicals than paper. Accordingly, plastic labels are becoming increasingly popular for use on flexible plastic bottles.
• Attaching flexible plastic labels to flexible plastic bottles is normally accomplished in one of two ways.
• a pressure sensitive adhesive is applied to the label and the label attached to a previously formed bottle by pressure.
• IMFL In Mold Film Label
• the label is placed into the mold used to form the bottle by blow molding and the label incorporated physically into the plastic bottle itself as part of the blow molding operation.
• a heat-activatable adhesive is normally applied to the label for firmly bonding the label to the bottle body.
• flexible plastic labels are attached to flexible plastic bottles at high rates of speed.
• typical industrial applications using pressure sensitive labels can process as many as 200 bottles per minute and even up to 600 bottles per minute.
• typical industrial applications for IMFL 5 to 150 bottles per minute can be made with labels attached.
• the labels must also exhibit additional properties such as die cutability, matrix stripability, dispensability (i.e., with enough stiffness to be dispensed at high speed from a peel plate or handled for insertion in a mold) and the like.
• pressure sensitive labels further need to be repositionable, i.e., when misapplied they can be easily peeled off the bottle in a single piece with all the adhesive remaining on the label.
• the label body is made by coextruding a number of different plastic materials together to form a multilayer coextruded product.
• a real advantage of this approach is that the main body of the film can be formulated to maximize the desired gross mechanical properties of the label, while the skin layers of the product can be tailored for accepting printing ink, for receiving adhesives or both.
• titanium dioxide-coated mica particles Another material also known to impart laser markability to various types of plastics is titanium dioxide-coated mica particles. Such materials are sold, for example, under the name AFFLAIR ® by E. Merk Company of Raway, New Jersey and MEARLIN ® Lustre Pigments sold by the Mearl Corporation of New York, New York.
• the present invention utilizes known laser marking technology to impart laser imprinted images to the unique, flexible, plastic labels made in accordance with the present invention.
• These unique plastic labels are multilayer coextrudates which are produced by coextrusion of at least two different polymer materials to form a product with at least two and preferably at least three distinct polymer layers bonded together.
• such products are composed of an inner core layer and at least one outer skin layer.
• the product will have two outer skin layers, one on each side.
• One of these outer skin layers is typically intended to be ink printable (hereinafter “printing skin”), and accordingly the material used to form this layer and the manner of its extrusion are selected to maximize its ability to accept and retain printing ink.
• the other outer skin (hereinafter “bonding skin”) is intended for bonding or facilitating bonding of the label to a bottle.
• the bonding skin layer can either be adapted to receive a subsequently applied adhesive or, in fact, may constitute the adhesive itself.
• the bonding skin is preferably a material which promotes wdhesion of the acrylic adhesive to the olefin core, for example, an olefin copolymer containing polymerized vinyl acetate.
• a label having a highly olefinic core layer is intended to be attached by IMFL to a highly olefinic bottle made, for example, from HDPE (high density polyethylene)
• the bonding skin layer can itself comprise the heat-activatable adhesive normally used for this purpose.
• a homopolymer or copolymer of ethylene or propylene is a good example of an appropriate material for this purpose.
• the thickness of the inventive labels can vary widely. Typically, they range between 0.5 and 15 mils, more preferably 1 to 10 mils, even more preferably between about 2 and 5 mils, thick. Of this amount, the printing and bonding skins each occupy about 5 to 25 percent of the thickness of the label, more typically about 10 to 15 percent of the thickness of the label, while the core layer occupies the rest.
• manufacture of the inventive labels involves production of a continuous sheet or web of the coextrudate, orientation of the web or sheet usually in a single direction (machine direction) only, and finally cutting or otherwise subdividing the web or sheet into individual, discrete labels.
• the coextruded web or sheet after orientation is usually laminated to a release liner comprising the pressure sensitive adhesive, a release agent such as a silicone resin and a paper or film backing layer.
• the laminate so formed is then typically slit longitudinally into strips and the strips wound up on spools, which are stored and/or sold, as desired.
• the laminate strip after unwinding from the spool is fed to a printer/die cutter.
• This machine ink prints the desired graphics on the coextrudate layer and immediately cuts this layer plus attached adhesive into individual labels.
• a small strip of the coextrudate layer is typically left between adjacent labels so that the coextrudate layer after cutting is composed of a plurality of individual, discrete labels plus an intergral matrix of coextrudate material surrounding the individual labels.
• This matrix is then removed leaving a strip comprising a continuous paper backing layer carrying discrete, physically separated labels thereon, each label comprising an ink- printed coextrudate with attached pressure sensitive adhesive mounted on the backing layer via a silicone release agent.
• This strip is then fed to an automatic label applying machine which manipulates the strip, for example, by sliding or rolling the strip around a peel plate at high speed, to cause the individual labels to automatically detach from the backing strip and be projected onto suitably placed bottles.
• the procedure is similar, except that the coextruded web or sheet is not laminated to a release layer. Rather, the web or sheet, after optional winding up into bulk rolls for storage, is slit and subjected to printing/die cutting with the individual labels produced thereby being bundled together in a stack. The blow-molder then loads individual labels from the stack into the label magazine of his blow-molding machine for automatic incorporation into the blow molded bottles as part of the bottle forming operation.
• coextrudates which have been oriented in the longitudinal, or machine, direction only.
• orientation is done by stretching the coextrudate while still hot in the machine direction at a stretch ratio of about 2:1 to about 9:1, with stretch ratios of 4:1 to 6:1 being typical.
• using a 5:1 stretch ratio will reduce the overall extrudate thickness from 16 mils at the extrusion nozzle to approximately 3.2 mils after stretching and will orient the polymer chains in the machine direction to thereby impart considerable stiffness in this direction but not in the transverse direction.
• Other known methods for orienting polymer films for example compression orientation or "blowing" a film produced by extrusion through an annular orifice, can be used.
• the hot-stretched coextrudates produced as described above can also be annealed or "heat set" in accordance with known techniques.
• this is done after extrusion and initial chilling of the extrudate by reheating the extrudate to an elevated temperature, for example, 300°F.
• the coextrudates can be directly processed into labels. More typically, however, the coextrudates are taken up (i.e. wound around) suitable cores to form rolls of material typically containing 500 to 15,000, preferably 2,000 to 10,000, linear meters of material in the form of continuous sheets or webs. Such rolls, which can be subdivided radially (i.e., cut in planes perpendicular to their axes to form rolls of smaller axial width) or left as is, can be stored, shipped and sold for use as needed.
• the coextrudates of the present invention can be formed from any materials commonly employed for making coextrudate flexible plastic labels.
• a suitable material for making the core layer for many applications in accordance with the present invention is polyethylene of low, medium or high density between 0.915 and 0.965 specific gravity. This is a relatively low cost, extrudable film- forming material whose stiffness is dependent, among other things, on the density selected and whose body and strength are sufficient for most uses.
• Polyethylene of lower densities, down to a specific gravity of 0.890, may be employed for greater flexibility.
• a preferred material for the core layer is polypropylene (or a propylene copolymer) having a flex modulus ranging between about 130,000 and 300,000 psi at 73°F., depending on the stiffness desired.
• Still other preferred materials for forming the core layer comprise copolymers of olefin monomers with ethylenically unsaturated carboxylic acid ester comonomers, such as ethylene-vinyl acetate copolymer, as well as blends of such copolymers with any and all of the other polymers and copolymers described above.
• Still other preferred materials comprise physical blends of (l) polypropylene or copolymers of polypropylene and polyethylene and (2) ethylene-vinyl acetate (EVA) in weight ratios ranging from 50/50 to 80/20, preferably 55/45 to 65/35.
• EVA ethylene-vinyl acetate
• a physical blend of (1) a copolymer of polypropylene and polyethylene and (2) ethylene-vinyl acetate (EVA) is also preferred.
• a preferred core layer is a physical blend of polypropylene and EVA.
• Polystyrene is also a candidate material for the core layer particularly where a stiffer label is desired.
• inorganic fillers may be incorporated into the polymer forming the layer.
• Useful fillers include calcium carbonate, titanium dioxide and blends thereof. Pigments and dyes can also be added for imparting color thereto.
• materials found suitable for the skin layers of the inventive labels are materials which are formed predominantly from polyolefins.
• predominantly from polyolefin is meant that the layer is formed from a homopolymer or copolymer of a polyolefin or blends of such homopolymers and/or copolymers, with the proviso that at least 50% of the polymerized monomers in the layer are polyolefins.
• Examples of such materials are homopolymers and copolymers of ethylene and propylene such as polyethylene, polypropylene and ethylene/propylene copolymer, copolymers of olefin monomers with ethylenically unsaturated carboxylic acid or ethyleni- cally unsaturated carboxylic acid ester comonomers such as ethylene- vinyl acetate copolymer (EVA) and blends of such homopolymers and copolymers.
• EVA ethylene- vinyl acetate copolymer
• the polymers, copolymers and blends described above in connection with the core layer can be used.
• meltable film-forming substances used alone or in combination such as polyethylene methyl acrylic acid, polyethylene ethyl acrylate, polyethylene methyl acrylate, acrylonitrile butadiene styrene polymer, polyethylene vinyl alcohol, nylon, polybutylene, polystyrene, polyurethane, polysulfone, polyvinylidene chloride, polypropylene, polycarbonate, polymethyl pentene, styrene maleic anhydride polymer, styrene acrylonitrile polymer, ionomers based on sodium, potassium, calcium or zinc salts of ethylene/ methacrylic acid, polymethyl methacrylates, cellulosics, fluoroplastics, polyacryloni- triles, and thermoplastic polyesters.
• the intensity of the marks made as a result of laser marking will not be compromised, and in fact may be improved, by restricting the laser- opaque materials to the core of the extrudate rather than in its skins.
• keeping the laser-opaque material out of the skins also has the beneficial effect of not deleteriously affecting the physical properties, particularly the smoothness of the skins or their chemical nature either.
• the coextrudates can be made without adversely affecting the various mechanical properties such as dimensional stability, stiffness, high speed dispensability, die cutability, matrix stripability, repositionability and the like of the label product.
• any type of laser-opaque material can be employed in accordance with the present invention.
• materials known for their ability to absorb and/or reflect laser light of different wave lengths and energy densities and, as a result, "interact" with a polymer material in which they are contained to cause a visible mark to form The type of "interaction,” e.g., thermal degradation of the polymer, simple chemical reaction, generation of gas bubbles, etc., varies depending on the type and operation of the laser employed as well as the type of polymer material employed, and accordingly there must be a "match" of the laser-opaque material with the polymer employed as well as the type and operation of the laser employed.
• any known laser- opaque material can be employed, so long as it "matches" both the polymer as well as the type and operation of the laser employed.
• the preferred laser-opaque materials used in accordance with the present invention are solid, particulate materials.
• Solid particulate materials having a high aspect ratio, particularly those which have a platelet structure, are especially preferred.
• particulate materials it is preferable that they have an average particle size from 0.2 to 400, preferably 0.5 to 60, most preferably 1 to 25 microns .
• Especially preferred laser-opaque materials are titanium dioxide-coated mica particles. These materials are commercially available from E. Merck Corporation of Hawthorne, New York under the designation AFFLAIR ® and The Mearl Corporation of New York, New York under the designation of MEARLIN ® luster pigments. These materials typically have particle sizes of 1 to 200, preferably 1 to 60, more preferably 1 to 25 microns.
• the amount of laser-opaque material to be incorporated into the core layer of the inventive coextrudate products can vary widely. Basically, the minimum amount is that amount which is sufficient to form a visible marking of the desired intensity. The maximum amount, in turn, is usually dictated by economics, amounts over that necessary to produce a mark of a desired intensity being unnecessary. Typically, the amount will be on the order of 0.1 to 10 percent by weight, based on the weight of the material forming the core layer (including any other filler or pigment such as titanium dioxide, calcium carbonate and the like) . More typically, the amount of laser-opaque material will be on the order of about 0.5 to 5 percent by weight.
• the amount of laser opaque material in the core layer of the inventive labels in terms of effective thickness.
• effective thickness is meant the number obtained by multiplying the thickness of the core layer, measured in mils, times the concentration of the laser-opaque material in the core layer, measured in weight percent expressed as a decimal. Measured in this way, it is preferable that the amount of laser opaque material in the core layer be enough so that the effective thickness thereof is 0.005 to 0.15, more preferably 0.01 to 0.10, even more preferably 0.02 to 0.06.
• the labels are irradiated with laser light containing or embodying the desired information or image therein.
• Nd/YAG systems and pulsed carbon dioxide lasers.
• the Nd/YAG systems and carbon dioxide lasers are typically used for plastics.
• eximer lasers have also been used for this purpose.
• each of these types of lasers can be used, although pulsed carbon dioxide TEA (transverse excited atmosphere) lasers are preferred from the point of view of cost and reliability.
• the conditions of laser marking vary widely and are dependent on a number of factors such as the identity and amounts of laser-opaque materials in the films, film thickness and the like.
• energy densities on the order of 0.8 to 36, preferably 1.8 to 28.8, Joules per square centimeter per pulse at pulse durations of 50 to 1,000, preferably 100 to 300, nanoseconds are appropriate.
• the laser beam generated by the laser is passed through a suitable stencil containing the desired information to generate an information-containing laser beam.
• This beam is then focused onto the label to be marked and the label irradiated with the laser light for the imprinting process. Exactly how this is done is well known to those skilled in the art of laser marking, and any conventional procedure for this purpose can be employed in accordance with the present invention.
• a hot coextrudate was produced in accordance with the process described in U.S. 5,242,650 with a total thickness of 17.5 mils. The coextrudate was then hot stretched to make a film of 3.5 mils. In each example, the coextrudate was made with two identical skins, each skin layer making up 10% of the total thickness of the coextrudate and the remainder comprising the core.
• each film was them imprinted with a simulated date and lot code by means of a Blazer 6000 Pulsed Carbon Dioxide Laser made by Lasertechnics Corporation of Albuquerque, New Mexico.
• the laser beam produced was passed through a mask having a simulated date and lot code about one inch wide and then focused to a reduced size onto the target film to imprint the image thereon. Imprinting was done at different energy levels (3 and 4 Joules per pulse) and different reduction ratios (ratio of mask size to image size).
• the laser beam as produced by the laser has an energy density of 0.8 Joules/cm 2 , at a maximum energy of 5 Joules.
• the energy density of the beam as it strikes the target can be reduced from this value by reducing the energy of the laser or increased by reducing (narrowing) the beam size between the mask and the surface of the target.
• the approximate energy densities of the laser beam striking the targets were as follows:
• the laser produces silvery-gray laser imprinted marks.
• the images so produced were visually observed and rated using an arbitrary scale of from 0 (no mark) to 10 (black and very distinct) .
• a coextrudate having the following composition was produced:
• Table 2 shows that the laser marking technique as described above produced images having a fairly high degree of contrast or intensity under essentially all the conditions tried in the experiment. This shows that images of good intensity can be produced in accordance with the present invention, even though the laser-opaque material is buried in the core and not present in the skin layers.
• Example 1 was repeated except that initial film thickness was 15 mils before stretching and final fill thickness was 3 mils after stretching.
• the amount of laser-opaque material in the core was. varied from 0 to 3.8 weight percent, based on the weight of the core, to illustrate the effect of varying concentration of this material.
• the specific compositions of the different layers used in these examples is set forth in the following Table 3. Unless otherwise indicated, the polymers and copolymers used have the same compositions as in Example 1:
• Example 1 was repeated except that the coextrudates in Examples 7 and 8 had the composition set forth in the following Tables 5 and 6:
• Example 9 a single layer extrudate was used, this
• Example 7 shows that when the
• Example 9 was
• Example 9 coextrudate contained a significantly greater overall amount of laser-opaque material than the coextrudate of Example 7. Notwithstanding this greater amount of active ingredient, the images produced in the Example 9 coextrudate have essentially the same visual impact as those of the Example 7 coextrudate.
• Example 7 shows that the results obtained in Example 7 are almost identical to those obtained in Example 4 in which the coextrudate had an effective thickness of laser-opaque material of 0.023. This, in turn, shows that "effective thickness" is a meaningful number.
• Afflair 100 rather than Afflair 110.
• Afflair 100 is slightly larger in particle size, and as can be seen below appears to be slightly less effective.
• Example 14 a single layer extrudate was produced rather than a multi-layer extrudate, while in one of these examples, Example 14, the extrudate was not oriented after extrusion but was simply produced as cast.
• Table 8 The results obtained are set forth in the following Table 8:
• Example 11 Comparison of Examples 10 and 11 in the above Table 8 shows that providing an extrudate with protective skins as accomplished in accordance with the present invention, does not hurt and also may even prevent burn through at more intense conditions.
• the composite of Example 11 is essentially the same as Example 10 in terms of the active thickness and active ingredient concentration, the only difference between that in Example 11, protective skins having no laser-opaque material therein are provided. This is significant in that it shows the coextrudated skins can be fine tuned to meet performance criteria without reducing laser-markability at the same additive cost.
• Example 12 Comparison of Example 12, in which a single layer extrudate thicker than that of Example 10 and hence having more overall laser- opaque material than in Examples 10 or 11 (0.027 effective thickness rather than 0.0252) shows that the visual impact of this extrudate is no better than that of the coextrudate of Example 11 even though the extrudate of Example 12 has more laser-opaque material.
• Examples 13 and 14 are comparable in that both have the same effective thickness of laser-opaque material.
• the Example 14 product which is a single layer extrudate not subjected to orientation, provides a visual impact which is noticeably less intense than that provided by the Example 13 product which is composed of multiple layers having been oriented in the machine direction. This shows that the combination of burying the laser-opaque material in the core and orienting in at least the machine direction facilitates reduction in the amount of expensive laser-opaque material necessary to produce a visually acceptable image.
• Example 15
• the recipe for an opaque white flexible film with a print layer, and an adhesive layer is as follows:
• the above film was coextruded as in previous Examples 2 through 7, but the coextrudate thickness was 20 mils, and stretching was done to produce a film of 4.0 mils. As in the previous examples, the thickness of the top and bottom layers were each 10% of the total, the central layer making up the remaining 80%.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Laminated Bodies (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
• Labeling Devices (AREA)

Applications Claiming Priority (3)

Publications (3)

Family

ID=22984380

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (18)

Family Cites Families (2)

• 1995
  • 1995-06-06 AT AT95922091T patent/ATE201318T1/de not_active IP Right Cessation
  • 1995-06-06 AU AU26901/95A patent/AU709752B2/en not_active Ceased
  • 1995-06-06 DE DE69521045T patent/DE69521045T2/de not_active Expired - Fee Related
  • 1995-06-06 EP EP95922091A patent/EP0766546B1/de not_active Expired - Lifetime
  • 1995-06-06 WO PCT/US1995/006258 patent/WO1995034263A1/en active IP Right Grant
  • 1995-06-06 CA CA002192850A patent/CA2192850A1/en not_active Abandoned
  • 1995-06-06 ES ES95922091T patent/ES2157329T3/es not_active Expired - Lifetime
  • 1995-06-06 BR BR9508699A patent/BR9508699A/pt not_active IP Right Cessation

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events