KR20100133465A - Method for applying a pressure sensitive shrink label to an article - Google Patents

Abstract

The present invention discloses a method of applying a label (12) to an article (10), the method comprising: providing an article having a surface comprising at least one composite curved surface (16); Providing a label comprising (i) a heat shrinkable film having an inner surface and an outer surface, and (ii) a layer of pressure-sensitive adhesive on the inner surface of the heat shrinkable film, the label having a first corner and a contact area. Providing a label; Contacting the adhesive layer in the contact area of the article with the label; Simultaneously applying heat and pressure to the label in a direction from the contact area to the first corner such that the first edge of the label is attached to the article and the label shrinks to conform to the composite curved surface of the article, the heat and pressure being heated At least one hot air knife assembly comprising an air source, a flow control mechanism and one or more hot air slots.

Description

METHOD FOR APPLYING A PRESSURE SENSITIVE SHRINK LABEL TO AN ARTICLE}

Cross References to Related Applications

This application enjoys the benefit of part-continued applicants of PCT / US08 / 59397, filed April 4, 2008, and US Patent Application No. 12 / 237,761, filed September 25, 2008. Enjoys priority from U.S. Provisional Application No. 60 / 910,282, filed Apr. 5, 2007 and U.S. Provisional Application No. 60 / 938,019, filed May 15, 2007, the entire disclosure of which is hereby incorporated by reference. Included in

The present invention relates to pressure sensitive shrink labels. In particular, the present invention relates to pressure sensitive labels having good compliance with containers having complex shapes and to methods of applying such labels.

It is common practice to label a container or bottle to provide information such as the supplier of the container or the contents of the container. Such containers and bottles are available in a variety of shapes and sizes to hold a number of different types of materials such as detergents, chemicals, personal care products, automotive oils, beverages and the like.

Polymer film materials and film raw materials for use as labels in various fields have been described. Polymer Labels In particular, transparent polymer labels provide a label-free appearance in decorated glass and plastic containers and are increasingly demanded for many applications. Paper labels block the visibility of the container and / or its contents. Transparent polymer labels are growing much faster than paper labels in the package decoration market because they improve the visual aesthetics of containers, and hence products, and consumer product companies continue to improve the appearance of their products. Polymer film labels also have good mechanical properties such as tensile strength and wear resistance.

Conventional pressure sensitive adhesive (PSA) labels are often used on containers with curved surfaces and / or complex shapes without the formation of wrinkles, darts or lifts on the curved surfaces. Difficult to attach smoothly. The label size of a conventional PSA label is limited to no more than 6.35 mm (1/4 inch) from the edge (start) of the bend of the container or article. Shrink sleeve labels have been commonly used in these types of composite containers. The application of the label is performed using a process and method that is placed over the container and requires the formation of a tube or sleeve of heat shrink film that is heated to shrink the heat shrink film to conform to the size and shape of the container. As an alternative, the container is completely surrounded by a shrink label using a process in which the shrink film is applied directly to the container from a continuous roll of film material and then heat is applied to conform the label enclosed in the container. . However, label defects may occur during the labeling process or during the labeling process for simple or complex shaped bottles in the post-labeling process. These misapplied labels result in high waste incidence or expensive additional processing steps.

The present invention provides pressure sensitive adhesive labels that require less material than shrink sleeves or shrink envelope labels and can be applied to containers and articles on complex shapes and composite curved surfaces at low cost. In addition, the labels of the present invention allow a user to expand the billboard or graphics area of a conventional pressure sensitive label on containers and articles having complex shapes and / or complex curved surfaces.

Labels are provided for application on curved or non-planar surfaces comprising a heat shrinkable film and a pressure sensitive adhesive. In one embodiment, a pressure sensitive adhesive label for applying on a surface having at least one composite curved surface is provided, the label being a heat shrinkable film having an inner surface and an outer surface and a machine direction and a cross direction, wherein the film is A film having a final shrinkage rate (S) in at least one direction of at least 10% at 90 ° C., with a shrinkage rate of S ± 20% in another direction; And a layer of pressure sensitive adhesive on the inner surface of the heat shrinkable film. The shrink film has a moderately balanced shrinkage in both the machine and transverse directions. In one embodiment, the film has a final shrinkage rate (S) in at least one direction of at least 10% at 90 ° C., and a shrinkage rate in the other direction is S ± 10%. The label may further include a release liner removably attached to the adhesive layer.

An article bearing a label is also provided, the article having a surface comprising at least one composite curved surface; A pressure sensitive label comprising a heat shrinkable film having an inner surface and an outer surface and a layer of pressure sensitive adhesive on the inner surface of the heat shrinkable film, the label being applied to at least one composite curved surface.

A method of applying a label to an article having a surface having at least one compound curved surface is provided. The method comprises (a) providing an article having a surface comprising at least one composite curved surface; (b) providing a label comprising (i) a heat shrinkable film having an inner surface and an outer surface, and (ii) a layer of pressure-sensitive adhesive on the inner surface of the heat shrinkable film, the label comprising a central portion and a peripheral portion. Having, steps; (c) contacting the adhesive layer of the central portion of the label with the article; (d) applying pressure to the label in an outward direction from the central portion to the peripheral portion, wherein at least a portion of the label is applied to at least one composite curved surface of the article; (e) applying heat to at least a portion of the label to shrink at least a portion of the label to attach the label to the article. After or during heat, the label may be further compressed or wiped to completely adhere the label to the article to remove any residual defects in the label.

In one aspect of the invention, a method of labeling an article, comprising: providing an article having a surface comprising at least one composite curved surface; Providing a label comprising (i) a heat shrinkable film having an inner surface and an outer surface and (ii) a layer of pressure sensitive adhesive on the inner surface of the heat shrinkable film, the label having a first corner and a contact area Wow; Contacting the adhesive layer in the contact area of the article with the label; Simultaneously applying heat and pressure to the label in the direction from the contact area to the first corner such that the first edge of the label is attached to the article and the label shrinks to conform to the composite curved surface of the article, wherein the heat and pressure are heated air sources And, applied by at least one hot air knife assembly comprising a flow control mechanism and one or more hot air knife slots.

In one embodiment, the label includes a center and a second corner opposite the first corner, and the contact area is within or near the center of the label. In another embodiment, the label includes a second edge opposite the first edge and the contact area is proximate the second edge of the label.

Heat and pressure may be applied to the label by the hot air knife assembly, which hot air knife assembly rotates outwardly from the center of the label to the first and second corner portions to attach the label to the article. An air knife slot.

In one embodiment of the method of the invention, the first hot air knife slot exerts heat and pressure outwardly toward the first edge of the label at the center of the label, and the second hot air knife slot is at the center of the label. Heat and pressure are applied outwards towards the second corner. The article may be rotated about 180 ° prior to the step of applying heat and pressure to the label by the second hot air knife slot.

1 is a front view of a labeled container of the present invention as compared to a pressure sensitive label of the prior art.
2A-2D show a labeled container before and after applying heat to the label.
3A-3D show an embodiment of a container having a complex shape and a compound curved surface to which the label of the present invention is applied.
4A and 4B are front views of embodiments of a container having an irregular surface.
5 is a three-dimensional view of a portion of a labeled article having a compound curved surface.
6A-6D schematically illustrate a process for applying a label to an article having a compound curved surface.
7A and 7B schematically illustrate an embodiment of a process for labeling an article in which a working beam is used.
8A and 8B are schematic views of an air knife assembly for simultaneously applying heat and pressure to a label.
9A-9E are schematic diagrams of a process for labeling an article using multiple air knife slots.

Pressure sensitive adhesive labels are provided that can improve the appearance of labeled containers and articles by conforming to the appearance of the containers or articles and by providing an enlarged billboard appearance. End users and product designers must modify their designs to accommodate the limitations of current product decoration techniques. The label of the present invention gives the designer greater freedom in terms of product design to create greater shelf appeal and retain more information.

Containers and articles having composite curved surfaces typically must be completely surrounded by a shrink film to label or decorate the article. The label of the present invention can extend the label over complex curved surfaces without the need to completely enclose the article. This partial labeling impacts product cost and also product appearance. Conventional pressure sensitive labels cannot be applied to containers and articles without the undesirable dart and wrinkle formation of the labels. "Darting" is defined as the accumulation of excess label material that rises from the article to which the label is applied.

The labels of the present invention provide significant processing advantages over conventional shrink labels. For example, the pressure sensitive shrink labels of the present invention allow for more conventional printing and secondary processes such as foil and hot stamping. Conventional shrink labels must be printed below the surface, but the labels of the present invention can be printed on the surface, which improves the color quality, sharpness and texture of the printed image. Label films can be printed by water flexography, UV flexography, UV letter press, UV screens, solvent gravure and hot foil stamps.

The pressure sensitive label comprises a layer of (a) a heat shrinkable polymer film having an inner surface and an outer surface and a machine direction and a cross direction and (b) a pressure sensitive adhesive on the inner surface of the heat shrinkable film. The shrinkage of the heat shrinkable polymer film is balanced in the machine direction and in the cross direction. The final shrinkage rate S in at least one direction is at least 10% at 90 ° C., and the shrinkage rate in the other direction is S ± 20%. As an example of balanced shrinkage, if the shrinkage in the machine direction is 40% at 105 ° C., the shrinkage in the transverse direction is 40% ± 20% at 105 ° C. or in the range of 20% to 60%. In one embodiment, the final shrinkage (S) is at least 10% at 90 ° C. and the shrinkage in the other direction is S ± 10%. As used herein, the term “final shrinkage” refers to the maximum shrinkage a film can achieve at a particular shrinkage temperature as measured by ASTM method D1204.

The label is not provided as a shrink sleeve or tube that encapsulates the entire article or as a shrink envelope label that forms a junction where the ends of the label meet around the article. Labels of the present invention may be provided in a variety of shapes to conform to the article or container to which the label is applied, thereby providing greater freedom in container configuration and label design than conventional pressure-sensitive labels, or shrink envelope or shrink sleeve labels. Provide to the designer. The label can be cut into the required shape by any known method including for example die cutting and laser cutting. In one embodiment, the label is die cut to a particular configuration that compensates for the shrinkage of the label and the shape of the article to which the label is applied.

Since the label is compliant, the billboard or graphic area of the labeled container can further extend onto the container edge and onto the compound curved area of the container. The label may be 10% to 30% larger than the standard PSA label. As used herein, the term "composite curved surface" means a surface without direction of curvature. For example, the surface of a sphere or the surface of an ellipsoid has a curvature in all directions and thus has a compound curved surface. In contrast, the circumference has at least one directional surface with no curvature. As such, the simple circumference does not have a compound surface.

1 shows an expanded billboard area of the pressure sensitive shrink label of the present invention. The bottle 10 has a pressure sensitive shrink label 12 attached thereto. The dashed line 14 indicates the outer border of the standard pressure sensitive label. Standard (ie non-shrinkable) pressure sensitive labels may not extend over an area of the bottle having a compound curved surface 16 (the area between the inner dashed line and the outer solid line). When the label 12 is initially applied to the bottle 10, darts and pleats may form near the periphery of the label in the area of the bottle having the compound curved surface 16.

When a pressure sensitive label is applied to the container, heat is applied as necessary to eliminate defects when applying any label such as darts, edge lifts and wrinkles. In one embodiment, pressure and / or wiping may be used in addition to applying heat to remove any defects.

2A-2D, a label of the present invention and a method of applying a label are shown. In Figures 2A and 2B, a label 12 comprising a shrink film having a continuous layer of pressure sensitive adhesive applied thereto is applied to a container 10 having a compound curved surface around the circumference of the container and then brushed . No heat is applied to the label. The label 12 extends onto the compound curved surface 16 where darts 18 are formed near the perimeter 20 of the label. 2C and 2D show the labeled containers of FIGS. 2A and 2B after heat is applied to the labels. The dart 18 is removed and the label 12 conforms to the compound curved surface of the container 10 near the label periphery 20 without any defects.

The article or container to which the label is applied may be provided in various forms or shapes. Non-limiting examples of suitable articles include containers associated with and not associated with closures, trays, leads, toys, appliances, and the like. The article or container may be made of metal, such as any conventional polymer, glass or aluminum. Examples of suitable polymeric materials include high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride, polycarbonate, nylon, ethylene fluoride propylene, polystyrene, and the like. The article or container may be manufactured by a number of different processes known in the art, such as blow molding, injection molding, thermoforming, rotational molding, and the like.

Useful containers include, for example, bottles with closures on top of bottles, reversible bottles with closures on bottoms of bottles, bottles with pump dispensers or foam dispensers, tubes with closures and bottles with closures.

The container or article may have a transparent appearance. In one embodiment, the container or article has a translucent appearance. Translucent appearance can be achieved, for example, by the treatment of a transparent container or article, the addition of dyes and pearlescents to the base polymer, the use of polypropylene and / or polyethylene mixed with a purifying agent. Treatments include, for example, spray coating, sandblasting and mold surface treatment.

The container or article may include aesthetic features including, for example, textures, embossing, crystalline lenses, colors, holograms, frosted or matte colours, and the like. The surface of the container or article may be treated before applying the label. For example, the surface of the container or article may be flame treated, or a primer coating may be applied.

3A, 3B and 3C show containers with complex shapes and complex curved surfaces, respectively. 3A is a front view of the container 30a in which the container has a symmetrical spherical shape, with the container having a tapered concave area 32 at the top and a wider convex area 33 towards the bottom. Typically, shrink sleeves will be used to provide functional labels for such containers. Due to the present invention, the pressure-sensitive shrink label 31 can be smoothly applied to the container 30a without the appearance of a label defect. 3B is a front view of the container 30b having an asymmetrical shape, one side of the container having both concave region 34 and convex region 35, with the opposite side curved in a substantially similar manner along the length of the container. Form. Conventional methods of applying a label to the container 30b would have to apply a shrink sleeve label to conform to the complex shape of the container. Pressure sensitive shrink label 31 may be applied to container 30b to provide sufficient billboard area with much less material. 3C is a front view of the reversible bottle 30c with a closure 36 at the bottom and a label 31 applied to the front surface. 3D is a side view of the container 30c. The area 37 in the dashed line indicates the outer boundary of the standard pressure sensitive label that can be applied to the container. The complex shape of such containers requires two separate standard pressure sensitive labels to decorate the container since applying one continuous standard pressure sensitive label will result in the formation of dart and pleat defects. The pressure sensitive shrink label 31 can cover a much larger area, which gives the product designer greater design choices.

4A and 4B show containers with irregular surfaces, respectively. 4A is a front view of the vessel 40a with the raised ridge 42 along one side of the vessel. The opposite side of the container has a smooth surface. 4B is a front view of the container 40b having a ring 43 recessed in the circumferential direction along the length of the container. It should be noted that cylindrically shaped articles having areas of composite curved surfaces, such as containers 40a and 40b, are not excluded from the articles claimed herein.

5 is a schematic three-dimensional view of a portion of a labeled container. The container 50 has a surface comprising a compound curved surface. Label 52 is applied to the container and covers a portion of the compound curved area. Line 54 indicates an outer boundary to which a conventional pressure sensitive label can be applied without the formation of defects in the label. Region 56 indicates an expanded billboard area that can be obtained with the label of the present invention without the formation of defects such as wrinkles, edge lifts or darts.

Shrink film

Polymeric films useful in the label construction of the present invention possess balanced shrinking properties. The balanced shrinking property causes the film to tackle the darts and wrinkles initially formed in the label when the label is applied on the curved surface and to wipe the darts and wrinkles with minimal graphic twist of the label. A film with an unbalanced shrinkage, i.e. a film with a high degree of shrinkage in one direction and a low to medium shrinkage rate in the other direction, can cause the dart to be removed in one direction but worsen the formation of darts in the other direction. It is not particularly useful because it becomes. Useful films with balanced shrinkage allow for more diverse label shapes to be applied to more diverse container shapes.

In one embodiment, the polymer film has a final shrinkage (S) as measured by ASTM procedure D1204 in at least 10% of at least 10% at 90 ° C., and the shrinkage in the other direction is S ± 20%. . In another embodiment, the film has a final shrinkage rate (S) in at least one direction of about 10% to about 50% at 70 ° C., and a shrinkage rate in the other direction is S ± 20%. In one embodiment, the final shrinkage (S) is at least 10% at 90 ° C. and the shrinkage in the other direction is S ± 10%. In one embodiment, the shrinkage onset temperature of the film is in the range of about 60 ° C to about 80 ° C.

The shrink film should be heat shrinkable, but should have sufficient rigidity to be dispensed using conventional labeling equipment and processes including printing, die-cutting and label delivery. The stiffness of the film required depends on the size of the label, the speed at which the label is applied and the equipment applying the label to be used. In one embodiment, the shrink film has a stiffness in the machine direction (MD) of at least 5 mN as measured by the L & W bending resistance test. In one embodiment, the shrink film has a rigidity of at least 10 mN or at least 20 mN. The rigidity of the shrink film is important for proper dispensing of the label on the release plate at higher work line speeds.

In one embodiment, the die-cut label is an article or container in a work line process that applies an automated label at a work line speed of at least 100 units / minute, or at least 250 units / minute or at least 500 units / minute. Is applied to.

In one embodiment, the shrink film is measured by ASTM D882 in the machine direction (MD) of about 20,000 to about 400,000 psi and in the transverse direction (TD) of about 20,000 to about 400,000 psi. Has a 2% secant modulus. In yet another embodiment, the 2% percent split coefficient of the film is from about 30,000 to about 300,000 in the machine direction and from about 30,000 to about 300,000 in the cross direction. The film may have a lower modulus in the transverse direction than the machine direction (MD) so that the label is easily dispensed while maintaining a sufficiently low modulus in the TD for compliance and / or compressibility.

Polymer films can be produced by conventional processes. For example, the film can be made using a double bubble process or a tenter process, or can include blown films.

Shrink films useful in labels can be single layer construction or multilayer construction. The layer or layers of the shrink film may be formed from a polymer selected from polyesters, polyolefins, polyvinyl chlorides, polystyrenes, polylactic acids, copolymers and mixtures thereof.

Polyolefins include homopolymers or copolymers of olefins which are aliphatic hydrocarbons having one or more carbon-carbon double bonds. The olefins include alkenes comprising internal alkenes having carbon-carbon double bonds on non-terminal carbon atoms of carbon chains such as 1-alkenes and 2-butenes, also known as α-olefins such as 1-butene; Cyclic olefins having one or more carbon-carbon double bonds such as cyclohexene and norbornadiene; And cyclic polyenes which are non-cyclic aliphatic hydrocarbons having two or more carbon-carbon double bonds such as 1,4-butadiene and isoprene. Polyolefins include alkene homopolymers from a single alkene monomers such as polypropylene homopolymers; Alkene copolymers from at least one alkene monomer and at least one further olefinic monomer, wherein the alkene listed above such as propylene-ethylene copolymer and propylene-ethylene-butadiene copolymer is the main component of the copolymer; Cyclic olefin homopolymers from a single cyclic olefin monomer; Cyclic olefin copolymers from at least one cyclic olefin monomer and at least one further olefin monomer, wherein the cyclic olefins listed above are the main components of the copolymer; And mixtures of any of the above olefin polymers.

In one embodiment, the shrink film is a multilayer film comprising a core layer and at least one epidermal layer. The epidermal layer may be a printable epidermal layer. In one embodiment, the multilayer shrink film comprises a core and two epidermal layers, at least one epidermal layer being printable. The multilayer shrink film can be a coextruded film.

The film may have a thickness in the range of 0.5-20, 0.5-12, 0.5-8 or 1-3 mils. Differences in the layers of the film can include differences in terms of thermoplastic polymer component, additive component, orientation, thickness, or a combination thereof. The thickness of the core layer can be 50-95%, 60-95% or 70-90% of the thickness of the film. The thickness of the epidermal layer or the combination of the two epidermal layers can be 5-50%, 5-40% or 10-30% of the thickness of the film.

The film can be further processed on one or both of the top and bottom surfaces to improve performance in terms of printability or adhesion to the adhesive. The treatment may include, for example, a treatment of applying a surface coating such as lacquer, a treatment of applying a high energy discharge to induce a corona discharge to the surface, a treatment of applying a flame treatment to the surface, or a combination of any of the above treatments. In one embodiment of the invention the film is treated on both surfaces and in another embodiment the film is treated on one surface with corona discharge and flame treated on the other surface.

The layer of shrink film may contain pigments, fillers, stabilizers, light protectors or other suitable modifiers, if desired. The film may also contain anti-blocking agents, slip additives and antistatic agents. Useful antiblocking agents include inorganic particles such as clay, talc, calcium carbonate and glass. Slip additives useful in the present invention include particles of polysiloxanes, waxes, fatty acid amides, metal soaps and particles such as silica, synthetic amorphous silica and polytetrafluoroethylene powder. Antistatic agents useful in the present invention include alkali metal sulfonates, polyether-modified polydiorganosiloxanes, polyalkylphenylsiloxanes and tertiary amines.

In one embodiment, the shrink film is microperforated to allow the trapped air to be released from the interface between the label and the article to which the label is attached. In another embodiment, the shrink film is permeable to allow fluid to escape from the adhesive or from the surface of the article. In one embodiment, exhaust holes or slits are provided in the shrink film.

glue

A description of useful pressure sensitive adhesives is described in the Polymer Science and Engineering Encyclopedia [Vol. 13, Wiley-Interscience Publishers, New York, 1988]. Further description of useful PSAs is described in Polymer Science and Technology [Vol. 1, Interscience Publishers, New York, 1964. Conventional PSAs including acrylic PSA, rubber PSA and silicone PSA are useful. The PSA may be solvent based or an aqueous adhesive. Hot melt adhesives may also be used. In one embodiment, the PSA comprises an acrylic emulsion adhesive.

The adhesive and the side of the film to which the adhesive is applied have sufficient compatibility to allow good adhesive fixation. In one embodiment, the adhesive is selected such that the label can be removed from the PET container cleanly up to 24 hours after applying the label. The adhesive is also chosen so that the adhesive component does not move into the film.

In one embodiment, the adhesive can be formed from an acrylic polymer. It is contemplated that any acrylic polymer capable of forming an adhesive layer having sufficient adhesion to adhere to a substrate can function in the present invention. In some embodiments, acrylic polymers for pressure sensitive adhesive layers include those formed from the polymerization of at least one alkyl acrylate monomer containing from about 4 to about 12 carbon atoms in an alkyl functional group, and in US Pat. No. 5,264,532 It is present in an amount of about 35-95% by weight of the polymer or copolymer as disclosed. Optionally, the acrylic pressure sensitive adhesive can be formed from a single polymer species.

The glass transition temperature of the PSA layer comprising the acrylic polymer can be varied by adjusting the amount of polar or “hard monomer” in the copolymer as disclosed by US Pat. No. 5,264,532, which is incorporated herein by reference. The larger the weight percentage of the hard monomers of the acrylic copolymer, the higher the glass transition temperature. Hard monomers contemplated as useful for the present invention include vinyl esters, carboxylic acids and methacrylates in weight-based concentrations within the range of about 0 to about 35 weight percent of the polymer.

PSAs may be acrylic, such as those disclosed in US Pat. No. 5,164,444 (acrylic emulsion), US Pat. No. 5,623,011 (adhesive acrylic emulsion) and US Pat. No. 6,306,982. The adhesive may also be rubber based, such as those disclosed in US Pat. No. 5,705,551 (rubber hot melt). The adhesive may also be a radiation curable mixture of monomers and initiators and other components, such as those disclosed in US Pat. No. 5,232,958 (UV cured acrylic) and US Pat. No. 5,232,958 (EB cured). The disclosures of these patents, such as those associated with acrylic adhesives, are incorporated herein by reference.

Commercially available PSAs are useful in the present invention. Examples of these adhesives are HM-1597, HL-2207-X, HL-2115-X, HL-2193-X, H. B., St. Paul, Minn. Hot Melt PSAs available from H.B. Fuller Company. Other useful commercially available PSAs include those available from Century Adhesives Corporation, Columbus, Ohio. Another useful acrylic PSA includes a mixture of dispersion tackifier particles and emulsion polymer particles as generally described in Example 2 of US Pat. No. 6,306,982. The polymers are prepared by emulsion polymerization and methacryl comonomers of 2-ethylhexyl acrylate, vinyl acetate, dioctyl maleate and acrylic, as described in US Pat. No. 5,164,444, whereby about Resulting in a latex particle size of 0.2 μm and a gel content of about 60%.

A commercial example of a hot melt adhesive is H2187-01, sold by Ato Findley, Inc., WoWartusa, Wisconsin. In addition, the rubber-based block copolymer PSA described in US Pat. No. 3,239,478 can also be used in the adhesive construction of the present invention, which patent is incorporated by reference for its disclosure of such hot melt adhesives described more fully below. It is included here.

In another embodiment, the pressure sensitive adhesive contains linear, branched, graft or radical block copolymers represented by double block structure AB, triple block ABA, radical or bonding structure (AB) _n and combinations thereof. Useful rubber-based elastomeric materials, wherein A represents a hard thermoplastic phase or block that is non-rubber, glassy or crystalline but fluid at higher temperatures at room temperature, and B is soft, which is rubber or elastomer at service temperature or room temperature Represents a block. These thermoplastic elastomers may include from about 75% to about 95% by weight of rubber segments and from about 5% to about 25% by weight of non-rubber segments.

Non-rubber segments or hard blocks include polymers of mono- and polycyclic aromatic hydrocarbons, in particular vinyl-substituted aromatic hydrocarbons which may be monocyclic or bicyclic in nature. Rubber materials such as polyisoprene, polybutadiene and styrene butadiene rubber may be used to form the rubber blocks or segments. Particularly useful rubber segments include polydiene and saturated olefin rubbers of ethylene / butylene or ethylene / propylene copolymers. The latter rubber can be obtained from the corresponding unsaturated polyalkylene moieties such as polybutadiene and polyisoprene by hydrogenation thereof.

Block copolymers of vinyl aromatic hydrocarbons and conjugated dienes that may be used include any block copolymer exhibiting elastomeric properties. The block copolymer can be a double block, triple block, multi block, star block, poly block or graft block copolymer. Throughout this specification, the terms double block, triple block, multi block, poly block and graft or grafted-block for the structural features of the block copolymers are described in the Polymer Science and Engineering Encyclopedia [Vol. 2, (1985) John Wiley & Sons, Inc., New York, pp. 325-326, and in block copolymers [Science, Dale J. D. J. Meier, Ed., Harwood Academic Publishers, 1979, pages 1-5. The usual meaning as defined by J.E. McGrath should be provided.

Such block copolymers may contain various proportions of conjugated diene to vinyl aromatic hydrocarbons, including those containing up to about 40 weight percent vinyl aromatic hydrocarbons. Thus, multi-block copolymers having linear or radical symmetry or asymmetry and having a structure represented by the formulas AB, ABA, ABAB, BAB, (AB) _{0,1,2 ...} BA, etc. can be used, wherein Where A is a polymer block of vinyl aromatic hydrocarbon or a conjugated diene / vinyl aromatic hydrocarbon tapered copolymer block, and B is a rubber polymer block of conjugated diene.

Block copolymers include sequential addition of monomers, incremental addition of monomers or such as described in US Patent Nos. 3,251,905; 3,390,207; 3,598,887; 3,598,887; And well known block polymerization or copolymerization procedures, including binding techniques such as those described in US Pat. No. 4,219,627. As noted, tapered copolymer blocks can be incorporated into multi-block copolymers by copolymerizing a mixture of conjugated diene and vinyl aromatic hydrocarbon monomers using differences in their copolymerization reaction rates. US Patent No. 3,251,905; 3,639,521; And various patents, including US Pat. No. 4,208,356, describe the preparation of multi-block copolymers containing tapered copolymer blocks, the disclosures of which are incorporated herein by reference.

Conjugated dienes that can be used to prepare polymers and copolymers are those containing 4 to about 10 carbon atoms and more specifically 4 to 6 carbon atoms. Examples include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-pentadiene, 1,3-hexadiene and the like. Include. Mixtures of these conjugated dienes may also be used.

Examples of vinyl aromatic hydrocarbons that can be used to prepare the copolymer include styrene and o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, β-methylstyrene, p-isopropylstyrene, 2,3-dimethylstyrene, o-chlorostyrene, p-chlorostyrene, o-bromostyrene, 2-chloro-4-methylstyrene, etc. Substituted styrene.

Most of the copolymers of the conjugated dienes and vinyl aromatic compounds described above are commercially available. The number average molecular weight of the block copolymer before hydrogenation is about 20,000 to about 500,000 or about 40,000 to about 300,000.

The number average molecular weight of the individual blocks in the copolymer can vary within certain limits. In most cases, the vinyl aromatic block will have a number average molecular weight of about 2,000 to about 125,000 or about 4,000 to about 60,000. The conjugated diene blocks before or after hydrogenation will have a number average molecular weight on the order of about 10,000 to about 450,000 or about 35,000 to 150,000.

Furthermore, prior to hydrogenation, the vinyl content of the conjugated diene moiety is from about 10% to about 80% or from about 25% to about 65%, especially from 35% to 55% when the modified block copolymer is required to exhibit rubber elasticity. to be. The vinyl content of the block copolymer can be measured by nuclear magnetic resonance.

Specific examples of diblock copolymers include styrene-butadiene (SB), styrene-isoprene (SI) and their hydrogenated derivatives. Examples of triple block polymers include styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), α-methylstyrene-butadiene-α-methylstyrene and α-methylstyrene-isoprene-α-methylstyrene . Examples of commercially available block copolymers useful as adhesives in the present invention include those available from Kraton Polymers LLC under the trade name KRATON.

Upon hydrogenation of the SBS copolymer comprising rubber segments of a mixture of 1,4 and 1,2 isomers, a styrene-ethylene-butylene styrene (SEBS) block copolymer is obtained. Similarly, hydrogenation of SIS polymers results in styrene-ethylene propylene-styrene (SEPS) block copolymers.

Selective hydrogenation of the block copolymer can be carried out by various well known processes including hydrogenation in the presence of Raney nickel and precious metals such as platinum, palladium, and soluble transition metal catalysts. Suitable hydrogenation processes that can be used are those in which the diene-containing polymer or copolymer is dissolved in an inert hydrocarbon diluent such as cyclohexane and hydrogenated by reaction with hydrogen in the presence of a soluble hydrogenation catalyst. Such procedures are disclosed in US Pat. Nos. 3,113,986 and 4,226,952, the disclosures of which are incorporated herein by reference. The hydrogenation of such block copolymers is performed to that extent in such a way as to produce a selectively hydrogenated copolymer having a residual unsaturated content in the polydiene block of about 0.5% to about 20% of its original unsaturated content prior to hydrogenation.

In one embodiment, the conjugated diene portion of the block copolymer is saturated by at least 90% and more often by at least 95%, while the vinyl aromatic portion is not significantly hydrogenated. Particularly useful hydrogenated block copolymers are the hydrogenation products of block copolymers of styrene-isoprene-styrene, such as styrene- (ethylene / propylene) -styrene block copolymers. When the polystyrene-polybutadiene-polystyrene block copolymer is hydrogenated, the 1,2-polybutadiene to 1,4-polybutadiene ratio in the polymer is preferably about 30:70 to about 70:30. When this block copolymer is hydrogenated, the resulting product is similar to the regular copolymer block of ethylene and 1-butene (EB). As described above, when the conjugated diene is employed as isoprene, the resulting hydrogenated product is similar to the regular copolymer block of ethylene and propylene (EP).

A number of selectively hydrogenated block copolymers are commercially available from Kraton Polymers under the generic trade name “Kraton G”. One example is Kraton G1652, a hydrogenated SBS triple block comprising about 30% by weight of styrene end blocks and an intermediate block that is a copolymer of ethylene and 1-butene (EB). Lower molecular weight versions of G1652 are available under the trade name Kraton G1650. Kraton G1651 is another SEBS biblock copolymer containing about 33% styrene by weight. Kraton G1657 is an SEBS biblock copolymer containing about 13% by weight of styrene. This styrene content is lower than the styrene content in Kraton G1650 and Kraton G1652.

In another embodiment, the selectively hydrogenated block copolymer is of the formula

B _n (AB) _o A _p

Where n = 0 or 1; o is 1 to 100; p is 0 or 1; Each B before hydrogenation is a polymerized conjugated diene hydrocarbon block having a number average molecular weight predominantly between about 20,000 and about 450,000; Each A is primarily a polymerized vinyl aromatic hydrocarbon block having a number average molecular weight of about 2,000 to about 115,000; Block of A constitutes about 5% to about 95% by weight of the copolymer; Unsaturation of block B is less than about 10% of the original unsaturation. In another embodiment, the unsaturation of block B is reduced upon hydrogenation to less than 5% of its original value, and the average unsaturation of the hydrogenated block copolymer is reduced to less than 20% of its original value.

Block copolymers are functional groups that can be obtained by reacting α, β-olefin unsaturated monocarboxylic or dicarboxylic acid reagents onto selectively hydrogenated block copolymers of vinyl aromatic hydrocarbons and conjugated dienes as described above. It may also include a polymer having. The reaction of the carboxylic acid reagent in the graft block copolymer can be carried out in solution in the presence of free radical initiators or by a melting process.

Preparation of various selectively hydrogenated block copolymers of conjugated dienes and vinyl aromatic hydrocarbons grafted with carboxylic acid reagents is described in U.S. Patent Nos. 4,578,429; A number of patents are disclosed, including 4,657,970 and 4,795,782, the disclosures of which are related to the preparation of grafted selectively hydrogenated block copolymers of conjugated dienes and vinyl aromatic compounds and the preparation of such compounds It is incorporated herein by reference. U.S. Patent 4,759,782 describes and provides examples of preparation of grafted block copolymers by solution process and melting process. U.S. Patent No. 4,578,429 is a graft of maleic anhydride and Kraton G1652 (SEBS) polymer to 2,5-dimethyl-2,5-di (t-butylperoxy) hexane by melt reaction in a twin screw extruder. Contains an example.

Examples of selectively hydrogenated copolymers treated with commercially available maleic acid of styrene and butadiene include Kraton FG1901X, FG1921X and FG1924X, often referred to as selectively hydrogenated SEBS copolymers treated with maleic acid. FG1901X contains about 1.7% by weight of the binding functional group as succinic anhydride and about 28% by weight of styrene. FG1921X contains about 1% by weight of the binding functional group as succinic anhydride and 29% by weight of styrene. FG1924X contains about 13% by weight of styrene and about 1% by weight of succinic anhydride.

Useful block copolymers are also available from Nippon Zeon Co., Tokyo, Japan. For example, Quintac 3530 is available from Nippon Xeon and is believed to be a linear styrene-isoprene-styrene block copolymer.

Unsaturated elastomers and other polymers and copolymers that are not inherently tacky can be endowed with adhesion when synthesized with an external tackifier. Tackifiers are generally hydrocarbon resins, wood resins, rosin, rosin derivatives, and the like, which are present at concentrations in the range of about 40% to about 90% or about 45% to about 85% by weight of the total adhesive composition. It imparts pressure sensitive adhesive properties to the elastomeric adhesive composition. Compositions containing less than about 40 weight percent of a tackifying additive generally do not exhibit sufficient "quickstick" or initial adhesion enough to function as a pressure sensitive adhesive and thus not inherently tacky. On the other hand, compositions with excessively high concentrations of tackifiers generally exhibit bond strengths that are so small that they do not function properly in the structures of most intended application applications made in accordance with the present invention.

It is contemplated that any tackifier known by those skilled in the art to be compatible with the elastomeric composition can be used with the embodiments of the present invention. One such tackifier that has been found to be useful is Wingtak 10, a synthetic polyterpene resin that is liquid at room temperature and sold by Goodyear Tire and Rubber Company, Akron, Ohio, USA. Wing Tak 95 is a synthetic tackifying resin also available from Goodyear, which mainly comprises polymers derived from piperylene and isoprene. Other suitable tackifying additives may include the aliphatic hydrocarbon resin Escorrez 1310 and the C ₅ -C ₉ (aromatic modified aliphatic) resin Escorez 2596, both of which are exons in Irving, Texas, USA. Manufactured by (Exxon). Of course, as can be appreciated by those skilled in the art, a variety of different tackifying additives can be used to practice the present invention.

In addition to tackifiers, other additives may be included in the PSA to impart the desired properties. For example, plasticizers can be included, which are known to reduce the glass transition temperature of adhesive compositions containing elastomers. An example of a useful plasticizer is Shellflex 371, a naphthenic processing oil available from Shell Lubricants, Texas, USA. Antioxidants may also be included in the adhesive composition. Suitable antioxidants include Irgafos 168 and Irganox 565 available from Ciba-Geigy, Hodon, NY. Cutting agents such as waxes and surfactants may also be included in the adhesive.

Pressure sensitive adhesives can be applied from solvents, emulsions or suspensions, or from hot melts. The adhesive can be applied to the inner surface of the shrink film by any known method. For example, the adhesive can be applied by die coating curtain coating, spraying, dipping, rolling, gravure or flexographic techniques. The adhesive can be applied to the shrink film in a continuous layer, discontinuous layer or in a predetermined pattern. The adhesive layer coated in a predetermined pattern substantially covers the entire inner surface of the film. As used herein, "substantially covering" is intended to mean a pattern that is continuous on the film surface, merely in the form of a strip along the leading or trailing edge of the film or as a "spot weld" on the film. It is not intended to include the applied adhesive.

In one embodiment, an adhesive deadener is applied to a portion of the adhesive layer thereby causing the label to adhere to the article of complex shape. In one embodiment, a non-adhesive material, such as ink dots or microbeads, is applied to at least a portion of the adhesive surface and thereby labels so that the adhesive layer slides on the surface of the article and / or labels and articles The trapped air escapes at the interface between them.

Single layer adhesives may be used, or multiple layers of adhesives may be used. Depending on the shrink film used and the article and container to which the label is to be applied, using a first adhesive layer adjacent to the shrink film and a second adhesive layer having a different composition on the surface to be applied to the article or container for sufficient adhesion, peel strength and shear strength It may be desirable.

In one embodiment, the pressure sensitive adhesive has sufficient shear or bond strength to prevent excessive shrinkage of the label when attached to the article upon action of heat after placement of the label on the article, the film from the label being lifted from the article. Sufficient peel strength to be prevented and sufficient adhesion or gripping properties to allow sufficient adhesion of the label to the article during the application of the label. In one embodiment, the adhesive is moved with the label as the shrink film shrinks when heat is applied. In another embodiment, the adhesive holds the label in place so that the label does not move as the shrink film shrinks.

The heat shrinkable film may include other layers in addition to the single or multilayer heat shrinkable polymer film. In one embodiment, a metallized coating of thin metal film is deposited on the surface of the polymer film. The heat shrinkable film may also include a print layer on the polymer film. The printing layer may be located between the heat shrink layer and the adhesive layer or may be on the outer surface of the shrink layer. In one embodiment, the film is reverse printed with a design, image or text such that the print side of the epidermis is in direct contact with the container to which the film is applied. In this embodiment, the film is transparent.

The label of the present invention may also comprise a layer of ink-receiving composition which, if present, improves the printability of the metal layer and the quality of the print layer thus obtained. Various such compositions are known in the art and these compositions generally comprise binders and pigments such as silica and talc dispersed in the binder. The presence of the pigment reduces the drying time of some inks. Such ink-receiving compositions are described in US Pat. No. 6,153,288 (shih et al.), The disclosure of which is incorporated herein by reference.

The print layer may be an ink or graphic layer, and the print layer may be a monochrome or multicolor printing layer depending on the printed message and / or the intended design. These include variable print data such as serial numbers, bar codes, trademarks and the like. The thickness of the print layer is typically in the range of about 0.5 to about 10 μm, in one embodiment in the range of about 1 to about 5 μm, and in another embodiment about 3 μm. Inks used in the printing layer include commercially available aqueous, solvent-based or radiation curable inks. Examples of these inks are Sun Sheen (Sun Chemical's product identified as alcohol dilutable polyamide inks), Suntex MP (surface printed acrylic coated substrate, PVDC coated substrate and polyolefin). Sun Chemical's product identified as a solvent-based ink formulated for the film), X-Cel [Product of Water Ink Technologies identified as an aqueous film ink printing a film substrate] , Uvilith AR-109 Rubine Red (product of Daw Ink, identified as UV ink) and CLA91598F (Product of Sun Chemical, identified as multi-binding black solvent-based ink) It includes.

In one embodiment, the print layer comprises polyester / vinyl ink, polyamide ink, acrylic ink and / or polyester ink. The printing layer may be formed in a conventional manner, such as by gravure, flexographic or UV flexographic printing, and the like, and the ink composition may be formed on one or more required areas of the resin, suitable pigments or dyes, and films of the type described above. One or more suitable volatile solvents. After adding the ink composition, the volatile solvent component (s) of the ink composition are volatilized, thereby leaving a non-volatile ink component to form a print layer.

The adhesion of the ink to the surface of the polymer shrink film or, if present, the metal layer, may be improved by techniques well known to those skilled in the art if necessary. For example, as mentioned above, an ink primer or other ink adhesion promoter may be applied to the metal layer or polymer film layer before applying the ink. Alternatively, the surface of the polymer film may be corona treated or flame treated to improve the adhesion of the ink to the polymer film layer.

Useful ink primers may be transparent or opaque, and the primers may be solvent based or aqueous based. In one embodiment, the primer is radiation curable (eg, UV). Ink primers can include lacquers and diluents. Lacquers include one or more polyolefins, polyamides, polyesters, polyester copolymers, polyurethanes, polysulfones, polyvinyridine chloride, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, sodium or zinc salts or ethylene Ionomers based on methacrylic acid, polymethyl methacrylates, acrylic polymers and copolymers, polycarbonates, polyacrylonitrile, ethylene-vinyl acetate copolymers and mixtures of two or more thereof. Examples of diluents that can be used include alcohols such as ethanol, isopropanol and butanol; Esters such as ethyl acetate, propyl acetate and butyl acetate; Aromatic hydrocarbons such as toluene and xylene; Ketones such as acetone and methyl ethyl ketone; Aliphatic hydrocarbons such as heptane; And mixtures thereof. The ratio of lacquer to diluent depends on the viscosity required to add the ink primer, the choice of this viscosity within the skill level. The ink primer layer may have a thickness of about 1 to about 4 μm or about 1.5 to about 3 μm.

Transparent polymeric protective top coat or overcoat layers may be present in the labels of the present invention. A protective top coat or overcoat provides the label with desirable properties before or after the label is attached to a substrate such as a container. In some embodiments, the presence of a transparent top coat layer over the print layer can provide additional properties such as antistatic properties, stiffness and / or weather resistance, and the top coat can be, for example, weather, sun, abrasion, moisture, moisture, and the like. It can protect the printed layer from the. The transparent top coat layer can improve the properties of the underlying print layer to provide a more glossy and richer image. The protective transparent protective layer can also be designed to be abrasion resistant, radiation resistant (eg UV), chemical resistant, heat resistant, thereby protecting the label, in particular the printing layer, from degradation from this cause. The protective overcoat may also contain an antistatic or anti-blocking agent to provide easier handling when the label is applied to the container at high speed. The protective layer can be applied to the printing layer by techniques known to those skilled in the art. The polymer film can be deposited from a solution added as a pre-formed film (laminated in the printing layer) or the like.

When a clear top coat or overcoat is present, the label may have a single layer or multilayer structure. The thickness of the protective layer is generally in the range of about 12.5 to about 125 μm and in one embodiment about 25 to about 75 μm. Examples of top coat layers are described in US Pat. No. 6,106,982, which is incorporated herein by reference.

The protective layer may comprise thermoplastic polymers of polyolefins, ethylene and propylene, polyesters, polyurethanes, polyacryl, polymethacryl, epoxy, vinyl acetate homopolymers, copolymers or trimers, ionomers and mixtures thereof.

The transparent protective layer may contain UV light absorbers and / or other light stabilizers. Among the useful UV light absorbers are the blocked amine absorbers available from Ciba Specialty Chemical under the trade name "Tinuvin". Light stabilizers that may be used are the trade name Tinuvin 111, Tinuvin 123, (bis- (1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate; Tinuvin 622, (4 Dimethyl succinic acid polymer with hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol); tinuvin 770, (bis- (2,2,6,6-tetramethyl-4-pipe) Lidinyl) -sebacate); and blocked amine light stabilizers available from Ciba Specialty Chemical under Tinuvin 783. Additional light stabilizers are tradenames "Chemassorb", in particular Chemassorb 119 and Chemaso. Blocking amine light stabilizers available from Ciba Specialty Chemical under V 944. The concentration of UV light absorbers and / or light stabilizers can be up to about 2.5% by weight and in one embodiment from about 0.05% to about 1% by weight. It is in range.

The transparent protective layer can contain an antioxidant. Any antioxidant useful for making thermoplastic films can be used. These include blocked phenols and organic phosphites. Examples include those available from Ciba Specialty Chemical under the trade names Irganox 1010, Irganox 1076 or Irgafos 168. The concentration of antioxidant in the thermoplastic film composition can be up to about 2.5% by weight and in one embodiment in the range of about 0.05% to about 1% by weight.

A release liner may be attached to the adhesive layer to protect the adhesive layer during transportation, storage and handling prior to labeling the substrate. The liner allows for efficient handling of the array of individual labels after the labels are die cut and the matrix is stripped from the layer of raw material to the point where the individual labels are sequentially distributed to the work line applying the labels. The release liner may have an embossed surface and / or have a non-adhesive material such as microbeads or printed ink dots applied to the surface of the liner.

fair

The process of labeling an article or container involves unusual operations and equipment. The process of providing an adhesive exposed label to a container or article to be decorated begins with conventional dispensing equipment that separates the label from the release liner through a release plate or tip. 6A-6D, a label 62 having a central portion 61 and a peripheral portion 63 surrounding the central portion, and an outer boundary defined by a label edge, initially presses on the label at the central portion. It is contacted with the container 60 by adding. Positioning the initial sticking point (s) 64 at the center of the label rather than the leading or surrounding portion of the label results in a more even distribution of any darts or wrinkles formed between the leading and trailing edges of the applied label. To facilitate. This, in turn, facilitates the removal of darts or wrinkles by applying heat.

For those articles having both composite curved and relatively planar regions, the label may initially be in contact with or within the composite curved surface, but closer to or within the relatively planar region of the container surface.

In one embodiment, the label is preheated to soften the shrink film and / or activate the adhesive layer.

Pressure is applied to the label delivered to a series of brushes, rollers, wipers, presses, pneumatic rollers or working beams in the outward direction as indicated by arrow 65 to obtain a close contact between the label and the container or article. This process is referred to herein as the "wipe" of the label. The wiping movement from the center to the edge presses any air trapped under the label to the outer edge as indicated by arrow 66 and produces a smaller and more evenly distributed dart at the edge of the label. Since the label covers the complex curved surface of the article, excess label material generally accumulates in the form of defects when applying darts, pleats, channels, bubbles and other labels within the perimeter of the label. Heat is applied to at least a portion of the label to completely and smoothly attach the label to the container as shown in FIG. 6D.

In one embodiment, pressure is applied to the label using a working beam system with foam rollers or foam covered beams. The foam roller or beam exerts a downward pressure in the longitudinal direction to the central area of the label, and then proceeds to the outer edge of the label, whereby any air and pleats, wrinkles and / or trapped under the label to the outer edge of the label Or other defects. This embodiment is shown in FIG. 7, wherein a container 70 with a label 71 applied to it is located on the lower foam block 72a of the working beam. The upper foam block 72b rests on the label 71 on the container 70 to push air from below the center portion of the label to the periphery of the label as the label and the container are compressed between the foam blocks of the working beam. Downward pressure.

Once the label is applied and initial wiping is complete, excess label material darts and defects are removed by heating at least a portion of the label to deflate the darts and / or wrinkles. The label may be heated via a passage through a heat tunnel, pressurized air, steam tunnel, direct contact heat pad or form. In one embodiment, the label is heated to a temperature of at least 40 ° C. In one embodiment, the label is heated to at least 60 ° C, at least 70 ° C or at least 80 ° C.

Subsequent wiping of the label may be performed to remove any residual darts or wrinkles in the label. Pressure is again applied to the label in the direction outwardly relative to the label. The second wiping can be performed by a series of rollers, wipers, compactors, brushes, pneumatic rollers or walking beams. Subsequent wiping may be performed at the same time as heating the label or subsequent heating.

When applying a label to an article or container, the label may initially adhere to the article by applying pressure to the contact area of the label and then across the label in the direction to the first edge of the label. The contact area may be in the center of the label or may be adjacent to the second edge of the label opposite the first edge. For example, initial contact may be performed at the center of the label, and then pressure may be applied in the outward direction to the edge or perimeter of the label. In the alternative, initial contact may be performed near one corner of the label, and then pressure may be applied across the label to the opposite corner of the label. When applying a label to an article or container, it is desirable to move excess label material, ie darts or wrinkles, to at least one label edge. Excess material is typically moved in the direction of the compound curved surface (s), where the heat applied to the label will shrink the label, causing the label to conform to the compound curved surface and remove any darts or wrinkles formed. Heat and pressure can be applied to the label at the same time.

In one embodiment of the present invention, a method of labeling an article comprises providing an article having a surface comprising at least one composite curved surface; Providing a label comprising (i) a heat shrinkable film having an inner surface and an outer surface and (ii) a layer of pressure-sensitive adhesive on the inner surface of the heat shrinkable film, the label having a first corner and a contact area, Steps; Contacting the adhesive layer in the contact area with the article; Simultaneously applying heat and pressure to the label in the direction from the contact area to the first corner such that the first edge of the label is attached to the article and the label shrinks to conform to the composite curved surface of the article, wherein the heat and pressure are heated air sources And applied by at least one hot air knife assembly comprising a flow control mechanism and one or more hot air knife slots. The contact area may be located in or near the center of the label. In the alternative, the contact area may be proximate to the second edge of the label opposite the first edge.

8 illustrates an embodiment of the invention in which a hot air knife assembly is used to label an article or container. The label may be applied to one or both sides of the container. For simplicity, in FIG. 8 the label is applied only to one surface of the container. The hot air knife assembly includes a hot air source, a flow control mechanism and one or more hot air knife slots. As shown in FIG. 8A, two hot air knife slots 84a and 84b direct hot air to the center region 83c of the label 82 at high speed. Label 82 is a standard peel tip dispensing process (not shown) with leading edge [first edge 83a] and trailing edge [second edge 83b] not tacked down. It is first applied to the central region 83c of the container 81 by a tip dispensing process. The labeled container is conveyed to the air knife assembly via a conveyor. Depending on the size and structure of the container, additional hot air knife slots and / or hot air assemblies may be used to apply heat and pressure to the label. As shown in FIG. 8B, the hot air knives 84a and 84b direct hot air from the center region of the label 83c to the first and second corners 83a and 83b of the label 82. Rotate outward. When hot air is pressurized against the label 82, the air between the label and the container 81 is pressurized to the edges 83a and 83b of the label to keep the label 82 smooth and to remove air bubbles under the label or Decrease. Hot air directed at the label 82 softens the label and shrinks the label. Simultaneous application of heat and pressure from the air knife slots 84a and 84b to the label forces the label 82 to conform to the surface of the container 81 including the composite curved surface (s) of the container. An optional subsequent heating step can be used to further shrink the label. The advantage of this method is that surface defects do not affect the label because it is not in direct contact with the label. The advantage is that high speed processing is possible by good heat transfer to the label and continuous heat recovery of the air knife assembly. This method can be used to label various containers and various article shapes without retooling.

9 illustrates an embodiment where multiple air knife slots and / or air knife assemblies are used to label a container or article through sequential steps. The label may be applied to one or both sides of the container. For simplicity, the label is applied only to one surface of the container in FIG. 9. The hot air knife assembly includes a hot air source, a flow control mechanism and one or more hot air knife slots. In the initial stage shown in FIG. 9A, hot air knife slot 94 directs hot air at high speed to center region 93c of label 92. Label 92 is a standard peel tip dispensing process (not shown) with leading edge [first edge 93a] and trailing edge [second edge 93b] not tacked down. It is first applied to the central region 93c of the vessel 91 by a tip dispensing process. The labeled container is conveyed to the air knife assembly via a conveyor. As shown in FIG. 9B, when the container 91 is transported by the conveyor and passes through the air knife slot 94, hot air is pressed against the label 92 to the first edge 93a of the label, Heating the label allows it to conform to the surface of the container 91, while the second edge 93b is not compliant and / or adhered. The vessel is then rotated about 180 ° as shown in FIG. 9C. Next, as shown in FIG. 9D, the container 91 to which the label 92 is attached is provided with a second pressurizing hot air against the label 92 from the central portion 93c of the label to the second corner 93b. Transferred to hot air slot 95, heating the label causes the label to conform to the surface of the container 91 as shown in FIG. 9E. Depending on the size and structure of the container, additional air knife slots and / or hot hot air assemblies may be used to apply heat and pressure to the labels. An optional subsequent heating step can be used to further shrink the label.

Labeled articles of the present invention may be used in a variety of applications, including but not limited to personal care products, household chemicals, food and beverages, toys, electronics, pharmaceuticals, health care products, industrial products, and consumer electronics. have.

Yes

The following examples are intended only to illustrate the methods and embodiments according to the present invention and therefore should not be construed as imposing limitations on the claims.

Example 1:

The pressure sensitive shrink label consists of a 3 mil thick low density polyethylene multilayer shrink film designated by the trade name CorrrTuff from Sealed Air. The film is coated with acrylic emulsion adhesive S692N from Avery Dennison. The adhesive is retained on the paper Glassine BG-40 silicone uncoated liner. The label is formed to an oversize with dimensions of approximately 5 inches x 18.9 cm (3.5 inches), which is 20% larger than the industry standard recommended label size for the bottle to which the label is applied.

The 15 oz Johnson & Johnson baby lotion bottle with a compound surface is filled with water, closed and labeled with a Label-Aire 9000 Series labeler in 100 bottles per minute (BPM). through the labeler). The labeler has a double-feed screw with upper and lower belts at a speed coordinated with a label-air 2115-CD labeler head with a high torque stepper motor drive. The label is pressed down into a wiping device in the form of a walking beam, thereby providing a straight central outward force to induce air trapped under the label to the edge of the label and the resulting dart / pleat defects. Oversized labels when initially applied to the bottle result in unacceptable small dart and pleat defects around the perimeter of the label. The labeled bottle is then processed through a conveyor wiping system of Leister hot forced air at 100 bpm. High speed 260 ° C. hot air heats the bottles and labels up to 50 ° C., thereby shrinking and reducing excess label material darts and pleats below to the bottle surface. The label is wiped with the working beam for good label contact. The darts shrink and are easily wiped flat after applying heat.

The finished labeled bottle with larger label area and larger graphic content is wiped smoothly without the darts, pleats, ridges or wrinkle wrinkles present in conventional pressure sensitive oversized labels. The darts do not return over time. Table 1 below shows the properties of the label components.

Example 2:

According to the process described in Example 1, a pressure-sensitive shrink label consisting of a 2 mil thick polypropylene multilayer shrink film designated under the tradename CZPA 200 from Innovia was applied to a bottle with a compound curved surface. After initial wiping, medium sized darts are formed. High speed hot air heats bottles and labels to 100 ° C. The darts shrink and are easily wiped flat after applying heat. The darts do not return after the passage of time.

Example 3:

Bottles with a pressure sensitive shrink label consisting of a 2 mil thick polylactic acid mono-shrink film designated by the brand name EARTHFIRST PLA from Plastic Suppliers according to the process described in Example 1 Is applied to. After initial wiping, medium sized darts are formed. High speed hot air heats bottles and labels to 70 ° C. The darts shrink and are easily wiped flat after applying heat. The darts do not return after the passage of time.

Comparative Example 4:

Pressure-sensitive shrink label consisting of a polypropylene monolayer roll-on-shrink-on film oriented in a machine direction 2 mils thick from Aberney Denison according to the process described in Example 1 It is applied to a bottle with a compound curved surface. High speed hot air heats bottles and labels to 70 ° C. The darts formed at the top and bottom of the label shrink and easily wipe off when heat is applied, but the darts formed at the leading and trailing edges remain. The removed darts do not return after time elapses.

Comparative Example 5:

According to the process described in Example 1, a pressure-sensitive shrink label consisting of a 1.9 mil thick transversely oriented polyvinyl chloride monolayer film designated by the trade name Penta Label from Kloeckner was used to produce a composite curved surface. To the bottle having. High speed hot air heats bottles and labels up to 60 ° C. The darts formed at the leading and trailing edges of the label shrink and easily wipe off when heat is applied, but the darts formed at the top and bottom of the label remain. The removed darts do not return after time elapses.

Comparative Example 6:

Pressure sensitive shrink label consisting of a glycol modified polyethylene terephthalate (PETG) monolayer film oriented in a cross direction of 2 mils thick, designated by the trade name Fusion 1775E from Mitsubishi, according to the process described in Example 1. It is applied to a bottle with a compound curved surface. High speed hot air heats bottles and labels to 50 ° C. The darts formed at the leading and trailing edges of the label shrink and easily wipe off when heat is applied, but the darts formed at the top and bottom of the label remain. The removed darts do not return after time elapses.

Comparative Example 7:

According to the process described in Example 1, a pressure-sensitive shrink label consisting of a 1.4 mil thick machine direction oriented polyvinyl chloride monolayer film designated by the trade name MF-L243 / 01 from Klukner was applied to a bottle with a compound curved surface. All. High speed hot air heats bottles and labels up to 60 ° C. The film is not compliant to the container. Initial wiping is poor with a large number of darts formed in all directions. The darts and ridges remain after heat and second wipe. The film exhibits excessive shrinkage.

Comparative Example 8:

According to the process described in Example 1, a pressure sensitive shrink label consisting of a 2.0 mil thick polypropylene multilayer film designated by trade name BTNY from Vifan was applied to a bottle with a compound curved surface. High speed hot air heats bottles and labels to 100 ° C. The darts formed do not shrink completely at high temperatures and are not wiped to an overall flat state. The darts are returned after the passage of time.

Comparative Example 9:

In accordance with the process described in Example 1, a pressure sensitive shrink label consisting of a 3.4 mil thick medium density polyethylene (MDPE) multilayer film designated under the trade name PE 85 from Charter Films was applied to a bottle with a composite curved surface. . High speed hot air heats bottles and labels to 100 ° C. The darts formed do not shrink completely at high temperatures and are not wiped to an overall flat state. The darts are returned after the passage of time.

While the present invention has been described in connection with the preferred embodiments thereof, it should be understood that various modifications thereof will be apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.

Claims (22)

In the method of labeling an article,
Providing an article having a surface comprising at least one composite curved surface;
Providing a label comprising (i) a heat shrinkable film having an inner surface and an outer surface and (ii) a layer of pressure-sensitive adhesive on the inner surface of the heat shrinkable film, the label having a first corner and a contact area, Steps;
Contacting the adhesive layer in the contact area of the article with the label;
Simultaneously applying heat and pressure to the label in the direction from the contact area to the first corner such that the first edge of the label is attached to the article and the label shrinks to conform to the composite curved surface of the article, wherein the heat and pressure are heated air sources And applied by at least one hot air knife assembly comprising a flow control mechanism and one or more hot air knife slots. The method of claim 1, wherein the label comprises a central portion and a second edge opposite the first edge, wherein the contact area is within or near the central portion of the label. The method of claim 1, wherein the label comprises a second edge opposite the first edge and the contact area is proximate to the second edge of the label. The method of claim 2, wherein the hot air knife assembly includes at least two hot air knife slots that rotate outwardly from the center of the label toward the first and second corners to attach the label to the article. 3. The method of claim 2 wherein the first hot air knife slot applies heat and pressure from the center of the label to the first edge of the label and the second hot air knife slot applies heat and pressure from the center of the label to the second edge of the label. How to add. The method of claim 5, further comprising rotating the article approximately 180 ° prior to applying heat and pressure to the label using a second hot air knife. The label of claim 1, wherein the label is provided with a release liner attached to the adhesive layer, the method further comprising separating the release liner from the label prior to contacting the label with the article. How to include. The method of claim 1, wherein the label is heated to a temperature of at least 40 ° C. 9. The method of claim 1, wherein the heat shrinkable film comprises a film selected from polyester, polyolefin, polyvinyl chloride, polystyrene, polylactic acid, copolymers thereof, and mixtures thereof. The method of claim 1, wherein the heat shrinkable film comprises a polyolefin. The method of claim 1, wherein the heat shrinkable film comprises a multilayer film having a core layer and at least one skin layer. The method of claim 1, wherein the stiffness of the film is at least 5 mN in the machine direction. The method of claim 1, wherein the label further comprises a printing layer between the heat shrinkable film and the adhesive layer, wherein the heat shrinkable film is transparent. The method of claim 1, wherein the label further comprises a printing layer on the outer surface of the heat shrinkable film. The method of claim 14, wherein the label further comprises a protective layer overlying the printing layer. The method of claim 1, wherein the adhesive layer comprises an emulsion adhesive. The method of claim 1, wherein the adhesive layer comprises a hot melt adhesive. The method of claim 1, wherein the adhesive layer comprises a solvent-based adhesive. The method of claim 1, wherein the pressure sensitive adhesive layer is continuous. The method of claim 1, wherein the pressure sensitive adhesive layer is patterned, the pattern substantially covering the inner surface of the film. The heat shrinkable film of claim 1, wherein the heat shrinkable film has a machine direction and a transverse direction, the film has a final shrinkage rate S in at least one direction of at least 10% at 90 ° C., and the other direction. Shrinkage to the method is S ± 20%. 22. The method of any one of claims 1 to 21, further comprising simultaneously applying heat and pressure to the label using a hot air knife assembly and then heating the label.

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