Patent Application
20120318430
The present invention relates to equipment and methods for applying labels such as shrink labels to a curved surface, and particularly to a compound curved surface.
It is known to apply labels to containers or bottles to provide information such as the supplier or the contents of the container. Such containers and bottles are available in a wide variety of shapes and sizes for holding many different types of materials such as detergents, chemicals, personal care products, motor oil, beverages, etc.
Polymeric film materials and film facestocks have been used as labels in various fields. Polymeric labels are increasingly desired for many applications, particularly transparent polymeric labels since they provide a no-label look to decorated glass and plastic containers. Paper labels block the visibility of the container and/or the contents in the container. Clear polymeric labels enhance the visual aesthetics of the container, and therefore the product. The popularity of polymeric labels is increasing much faster than that of paper labels in the package decoration market as consumer product companies are continuously trying to upgrade the appearance of their products. Polymeric film labels also have superior mechanical properties as compared to paper labels, such as greater tensile strength and abrasion resistance.
Traditional polymeric pressure sensitive (PSA) labels often exhibit difficulty adhering smoothly to containers having curved surfaces and/or complex shapes without wrinkling, darting or lifting on the curved surfaces. As a result, heat shrink sleeve labels have typically been used on these types of containers having compound curved surfaces. Direct screen printing is another method for applying indicia or other markings to curved surfaces. Labeling operations for heat shrink sleeve type labels are carried out using processes and methods that form a tube or sleeve of the heat shrink film that is placed over the container and heated in order to shrink the film to conform to the size and shape of the container. Alternatively, the containers are completely wrapped with a shrink label using a process in which the shrink film is applied to the container directly from a continuous roll of film material and then heat is applied to conform the wrapped label to the container. Regardless, label defects frequently occur during labeling operations of simple or compound shaped bottles during label application or in post label application processes. These misapplied labels result in high scrap or extra processing steps that can be costly.
Other processes for applying pressure sensitive shrink labels are known. In certain applications, a label is applied onto a container, heated, and any resulting defects then wiped to minimize such defects. A potential problem exists with a separate heat and wipe process with pressure sensitive shrink labels where edge defects are initially formed and then removed. Although the formation of the edge defects typically occurs in the same general region of the bottle, the defects are not in the exact same spot, nor of the same size or occur in the same number. These defects, collectively referred to herein as “darts” can in certain instances, be shrunk with heat. As these defects shrink, the area of the label comprising the dart is reduced along with the ink and print on top of the label dart. The shrinkage of the dart will shrink the print as well cause distortion of the print. Depending on the size of the dart and print fidelity, the distortion might be noticed and can in certain cases, be significant. This distortion may limit the type or quality of print in the shrink region of the label. Therefore, avoiding the formation of darts entirely would be of great benefit.
Accordingly, a need exists for a process and related system in which a shrink label could be applied to a curved surface and particularly a compound curved surface without the occurrence of darts or other defects.
The difficulties and drawbacks associated with previously known processes and label application systems are overcome in the present processes and systems, all of which are described in greater detail herein.
In one aspect, the present invention provides a system for applying labels onto articles. The system comprises a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers. The system also comprises a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. In this aspect of the invention, the lane extends in at least two different directions.
In another aspect, the present invention provides a system for applying labels onto articles. The system comprises a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers. The system also comprises a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned and parallel with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. In this aspect of the invention, the velocity of the first belt is different than the velocity of the second belt.
In still another aspect, the present invention provides a system for applying labels onto articles. The system comprises a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers. The system also comprises a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. In this aspect of the present invention, the lane extends in a relatively straight direction.
In still another aspect, the present invention provides a system for applying labels onto articles. The system comprises a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers. The system also comprises a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. In this aspect of the invention, the lane extends in an arcuate fashion.
In yet still another aspect, the present invention provides a method of applying labels onto articles using a system including a first assembly of a first belt extending about a first collection of rollers, and a second assembly of a second belt extending about a second collection of rollers. The first and second assemblies are arranged such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane having a region extending in at least two different directions. The method comprises initially adhering a label onto an outer surface of an article to receive the label. The method also comprises moving the first belt about the first collection of rollers and moving the second belt about the second collection of rollers such that the first and second belts are generally displaced alongside one another within the lane. And, the method comprises introducing the article and label initially adhered thereto at a first location in the lane such that the first and second belts contact and transport the article and label to a second location in the lane. The second location is located downstream of the first location and the region of the lane that extends in at least two different directions. As the article is transported from the first location to the second location, the label is fully contacted with and applied onto the article.
In another aspect, the present invention also provides a method of applying labels onto articles using a system including a first assembly of a first belt extending about a first collection of rollers and a second assembly of a second belt extending about a second collection of rollers. The first and second assemblies are arranged such that a portion of the first belt and a portion of the second belt are aligned and parallel with one another to define an article receiving lane. The method comprises initially adhering a label onto an outer surface of an article to receive the label. The method also comprises moving the first belt about the first collection of rollers at a first velocity and moving the second belt about the second collection of rollers at a second velocity different than the first velocity. And, the method further comprises introducing the article and label initially adhered thereto at a first location in the lane such that the first and second belts contact and transport the article and label to a second location in the lane. The second location is located downstream of the first location. As the article is transported from the first location to the second location, the label is fully contacted with and applied onto the article.
In still another aspect, the present invention provides a method of applying labels onto articles using a system including a first assembly of a first belt extending about a first collection of rollers and a second assembly of a second belt extending about a second collection of rollers. The first and second assemblies are arranged such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane extending in an arcuate fashion. The method comprises initially adhering a label onto an outer surface of an article to receive the label. The method also comprises moving the first belt about the first collection of rollers and moving the second belt about the second collection of rollers such that the first and second belts are generally displaced alongside one another within the lane. And, the method further comprises introducing the article and label initially adhered thereto at a first location in the lane such that the first and second belts contact and transport the article and label to a second location in the lane. The second location is located downstream of the first location. As the article is transported from the first location to the second location, the label is fully contacted with and applied onto the article.
And in yet another aspect, the present invention also provides a method of applying labels onto articles using a system including a first assembly of a first belt extending about a first collection of rollers and a second assembly of a second belt extending about a second collection of rollers. The first and second assemblies are arranged such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane extending in a relatively straight direction. The method comprises initially adhering a label onto an outer surface of an article to receive the label. The method also comprises moving the first belt about the first collection of rollers and moving the second belt about the second collection of rollers such that the first and second belts are generally displaced alongside one another within the lane. And, the method comprises introducing the article and label initially adhered thereto at a first location in the lane such that the first and second belts contact and transport the article and label to a second location in the lane. The second location is located downstream of the first location. As the article is transported from the first location to the second location, the label is fully contacted with and applied onto the article.
In another aspect, the invention provides a label application system comprising a label assembly including a polymeric film and a layer of adhesive on the film; and equipment for applying labels onto articles. The equipment comprises (i) a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers, and (ii) a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. The lane extends in at least two different directions.
In still another aspect, the present invention provides a label application system comprising a label assembly including a polymeric film and a layer of adhesive on the film; and equipment for applying labels onto articles. The equipment comprises (i) a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers, and (ii) a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. The lane extends in a relatively straight direction.
In yet another aspect, the present invention provides a label application system comprising a label assembly including a polymeric film and a layer of adhesive on the film; and equipment for applying labels onto articles. The equipment comprises (i) a first assembly of a first belt and a first plurality of rollers, the first belt extending around the first plurality of rollers, and (ii) a second assembly of a second belt and a second plurality of rollers, the second belt extending around the second plurality of rollers. The first assembly and the second assembly are arranged relative to one another such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. The lane extends in an arcuate fashion.
As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative and not restrictive.
The present invention provides further advances in strategies, methods, components, and equipment for applying labels and films onto curved surfaces such as outer curved surfaces of various containers. Although the present invention is described in terms of applying labels or films to containers, it will be understood that the invention is not limited to containers. Instead, the invention can be used to apply a variety of labels or films onto surfaces of nearly any type of article. The invention is particularly directed to applying shrink labels onto curved container surfaces. And, the invention is also particularly directed to applying labels such as heat shrink labels onto compound curved surfaces of various containers. References are made herein to containers having curved surfaces or compound curved surfaces. A curved surface is a surface defined by a line moving along a curved path. A compound curved surface is a particular type of curved surface in which the previously noted line is a curved line. Examples of a compound curved surface include, but are not limited to, the outer surface of a sphere, a hyperbolic parabloid, and a dome.
It is to be understood that the present invention can be used for applying labels and films onto a wide variety of surfaces, including planar surfaces and simple curved surfaces. However, as explained in greater detail herein, the invention is particularly well suited for applying labels and films onto compound curved surfaces most particularly, upon outwardly extending compound curved surfaces.
The polymeric films useful in the label constructions, the application of which the present invention is directed, preferably possess balanced shrink properties. The balanced shrink properties allow the film to shrink in multiple directions to thereby follow the contour of a compound curved surface as the label is applied upon the curved surfaces. Films having unbalanced shrink, that is, films having a high degree of shrink in one direction and low to moderate shrink in the other direction, can be used. Useful films having balanced shrink allow for a wider variety of label shapes to be applied to a wider variety of container shapes. Generally, films having balanced shrink properties are preferred.
In one embodiment, the polymeric film has an ultimate shrinkage (S) as measured by ASTM procedure D1204 in at least one direction of at least 10% at 90° C. and in the other direction, the shrinkage is within the range of S+/−20%. In another embodiment, the film has an ultimate shrinkage (S) in at least one direction of about 10% to about 50% at 70° C. and in the other direction, the shrinkage is within the range of S+/−20%. In one embodiment, the ultimate shrinkage (S) is at least 10% at 90° C. and in the other direction, the shrinkage is within the range of S+/−20%. The shrink initiation temperature of the film, in one embodiment, is in the range of about 60° C. to about 80° C.
The shrink film must be thermally shrinkable and yet have sufficient stiffness to be dispensed using conventional labeling equipment and processes, including printing, die-cutting and label transfer. The stiffness of the film required depends on the size of the label, the speed of application and the labeling equipment being 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 stiffness of at least 10 mN, or at least 20 mN. The stiffness of the shrink film is important for proper dispensing of labels over a peel plate at higher line speeds.
In one embodiment, die-cut labels are applied to the article or container in an automated labeling line process at a line speed of at least 30 units per minute, and preferably from at least 250 units per minute to at least 500 units per minute. It is contemplated that the present invention could be used in conjunction with processes operating as fast as 700 to 800 units per minutes, or more.
In one embodiment, the shrink film has a 2% secant modulus as measured by ASTM D882 in the machine direction (MD) of about 138,000,000 N/m2 to about 2,760,000,000 N/m2, and in the transverse (or cross) direction (TD) of about 138,000,000 N/m2 to about 2,760,000,000 N/m2. In another embodiment, the 2% secant modulus of the film is about 206,000,000 N/m2 to about 2,060,000,000 N/m2 in the machine direction and about 206,000,000 N/m2 to about 2,060,000,000 N/m2 in the transverse direction. The film may have a lower modulus in the transverse direction than in the machine direction so that the label is easily dispensed (MD) while maintaining sufficiently low modulus in the TD for conformability and/or squeezability.
The polymeric film may be made by conventional processes. For example, the film may be produced using a double bubble process, tenter process or may comprise a blown film.
The shrink film useful in the label may be a single layer construction or a multilayer construction. The layer or layers of the shrink film may be formed from a polymer chosen from polyester, polyolefin, polyvinyl chloride, polystyrene, polylactic acid, copolymers and blends thereof.
Polyolefins comprise homopolymers or copolymers of olefins that are aliphatic hydrocarbons having one or more carbon to carbon double bonds. Olefins include alkenes that comprise 1-alkenes, also known as alpha-olefins, such as 1-butene and internal alkenes having the carbon to carbon double bond on nonterminal carbon atoms of the carbon chain, such as 2-butene, cyclic olefins having one or more carbon to carbon double bonds, such as cyclohexene and norbornadiene, and cyclic polyenes which are noncyclic aliphatic hydrocarbons having two or more carbon to carbon double bonds, such as 1,4-butadiene and isoprene. Polyolefins comprise alkene homopolymers from a single alkene monomer, such as a polypropylene homopolymer, alkene copolymers from at least one alkene monomer and one or more additional olefin monomers where the first listed alkene is the major constituent of the copolymer, such as a propylene-ethylene copolymer and a propylene-ethylene-butadiene copolymer, cyclic olefin homopolymers from a single cyclic olefin monomer, and cyclic olefin copolymers from at least one cyclic olefin monomer and one or more additional olefin monomers wherein the first listed cyclic olefin is the major constituent of the copolymer, and mixtures of any of the foregoing olefin polymers.
In one embodiment, the shrink film is a multilayer film comprising a core layer and at least one skin layer. The skin layer may be a printable skin layer. In one embodiment, the multilayer shrink film comprises a core and two skin layers, wherein in at least one skin layer is printable. The multilayer shrink film may be a coextruded film.
The film can range in thickness from 12 to 500, or 12 to 300, or 12 to 200, or 25 to 75 microns. The difference in the layers of the film can include a difference in thermoplastic polymer components, in additive components, in orientation, in thickness, or a combination thereof. The thickness of the core layer can be 50 to 95%, or 60 to 95% or 70 to 90% of the thickness of the film. The thickness of a skin layer or of a combination of two skin layers can be 5 to 50%, or 5 to 40% or 10 to 30% of the thickness of the film.
The film can be further treated on one surface or both the upper and lower surfaces to enhance performance in terms of printability or adhesion to an adhesive. The treatment can comprise applying a surface coating such as, for example, a lacquer, applying a high energy discharge to include a corona discharge to a surface, applying a flame treatment to a surface, or a combination of any of the foregoing treatments. In an embodiment of the invention, the film is treated on both surfaces, and in another embodiment the film is treated on one surface with a corona discharge and is flame treated on the other surface.
The layers of the shrink film may contain pigments, fillers, stabilizers, light protective agents or other suitable modifying agents if desired. The film may also contain anti-block, slip additives and anti-static agents. Useful anti-block agents include inorganic particles, such as clays, talc, calcium carbonate and glass. Slip additives useful in the present invention include polysiloxanes, waxes, fatty amides, fatty acids, metal soaps and particulate such as silica, synthetic amorphous silica and polytetrafluoroethylene powder. Anti-static 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 trapped air to be released from the interface between the label and the article to which it is adhered. In another embodiment, the shrink film is permeable to allow fluid to escape from the adhesive or from the surface of the article to escape. In one embodiment, vent holes or slits are provided in the shrink film.
The present invention can be used for applying, processing, and otherwise in association with, a wide array of labels, film, and other members. For example, the invention can be used in conjunction with shrink labels, pressure sensitive labels, pressure sensitive shrink labels, heat seal labels, and nearly any type of label or film known in the packaging and labeling arts.
A description of useful pressure sensitive adhesives may be found in Encyclopedia of Polymer Science and Engineering, Vol. 13, Wiley-Interscience Publishers (New York, 1988). Additional description of useful PSAs may be found in Polymer Science and Technology, Vol. 1, Interscience Publishers (New York, 1964). Conventional PSAs, including acrylic-based PSAs, rubber-based PSAs and silicone-based PSAs are useful. The PSA may be a solvent based or may be a water based 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 enable good adhesive anchorage. In one embodiment, the adhesive is chosen so that the labels may be cleanly removed from PET containers up to 24 hours after application. The adhesive is also chosen so that the adhesive components do not migrate into the film.
In one embodiment, the adhesive may be formed from an acrylic based polymer. It is contemplated that any acrylic based polymer capable of forming an adhesive layer with sufficient tack to adhere to a substrate may function in the present invention. In certain embodiments, the acrylic polymers for the pressure sensitive adhesive layers include those formed from polymerization of at least one alkyl acrylate monomer containing from about 4 to about 12 carbon atoms in the alkyl group, and present in an amount from about 35 to 95% by weight of the polymer or copolymer, as disclosed in U.S. Pat. No. 5,264,532. Optionally, the acrylic based pressure sensitive adhesive might be formed from a single polymeric species.
The glass transition temperature of a PSA layer comprising acrylic polymers can be varied by adjusting the amount of polar, or “hard monomers”, in the copolymer, as taught by U.S. Pat. No. 5,264,532. The greater the percentage by weight of hard monomers included in an acrylic copolymer, the higher the glass transition temperature of the polymer. Hard monomers contemplated useful for the present invention include vinyl esters, carboxylic acids, and methacrylates, in concentrations by weight ranging from about 0 to about 35% by weight of the polymer.
The PSA can be acrylic based such as those taught in U.S. Pat. No. 5,164,444 (acrylic emulsion), U.S. Pat. No. 5,623,011 (tackified acrylic emulsion) and U.S. Pat. No. 6,306,982. The adhesive can also be rubber-based such as those taught in U.S. Pat. No. 5,705,551 (rubber hot melt). The adhesive can also include a radiation curable mixture of monomers with initiators and other ingredients such as those taught in U.S. Pat. No. 5,232,958 (UV cured acrylic) and U.S. Pat. No. 5,232,958 (EB cured). The disclosures of these patents as they relate to acrylic adhesives are hereby incorporated by reference.
Commercially available PSAs are useful in the invention. Examples of these adhesives include the hot melt PSAs available from H.B. Fuller Company, St. Paul, Minn. as HM-1597, HL-2207-X, HL-2115-X, HL-2193-X. Other useful commercially available PSAs include those available from Century Adhesives Corporation, Columbus, Ohio. Another useful acrylic PSA comprises a blend of emulsion polymer particles with dispersion tackifier particles as generally described in Example 2 of U.S. Pat. No. 6,306,982. The polymer is made by emulsion polymerization of 2-ethylhexyl acrylate, vinyl acetate, dioctyl maleate, and acrylic and methacrylic comonomers as described in U.S. Pat. No. 5,164,444 resulting in the latex particle size of about 0.2 microns in weight average diameters and a gel content of about 60%.
A commercial example of a hot melt adhesive is H2187-01, sold by Ato Findley, Inc., of Wauwatusa, Wis. In addition, rubber based block copolymer PSAs described in U.S. Pat. No. 3,239,478 also can be utilized in the adhesive constructions of the present invention, and this patent is hereby incorporated by a reference for its disclosure of such hot melt adhesives that are described more fully below.
In another embodiment, the pressure sensitive adhesive comprises rubber based elastomer materials containing useful rubber based elastomer materials include linear, branched, grafted, or radial block copolymers represented by the diblock structure A-B, the triblock A-B-A, the radial or coupled structures (A-B)n, and combinations of these where A represents a hard thermoplastic phase or block which is non-rubbery or glassy or crystalline at room temperature but fluid at higher temperatures, and B represents a soft block which is rubbery or elastomeric at service or room temperature. These thermoplastic elastomers may comprise from about 75% to about 95% by weight of rubbery segments and from about 5% to about 25% by weight of non-rubbery segments.
The non-rubbery segments or hard blocks comprise polymers of mono- and polycyclic aromatic hydrocarbons, and more particularly vinyl-substituted aromatic hydrocarbons that may be monocyclic or bicyclic in nature. Rubbery materials such as polyisoprene, polybutadiene, and styrene butadiene rubbers may be used to form the rubbery block or segment. Particularly useful rubbery segments include polydienes and saturated olefin rubbers of ethylene/butylene or ethylene/propylene copolymers. The latter rubbers may be obtained from the corresponding unsaturated polyalkylene moieties such as polybutadiene and polyisoprene by hydrogenation thereof.
The block copolymers of vinyl aromatic hydrocarbons and conjugated dienes that may be utilized include any of those that exhibit elastomeric properties. The block copolymers may be diblock, triblock, multiblock, starblock, polyblock or graftblock copolymers. Throughout this specification, the terms diblock, triblock, multiblock, polyblock, and graft or grafted-block with respect to the structural features of block copolymers are to be given their normal meaning as defined in the literature such as in the Encyclopedia of Polymer Science and Engineering, Vol. 2, (1985) John Wiley & Sons, Inc., New York, pp. 325-326, and by J. E. McGrath in Block Copolymers, Science Technology, Dale J. Meier, Ed., Harwood Academic Publishers, 1979, at pages 1-5.
Such block copolymers may contain various ratios of conjugated dienes to vinyl aromatic hydrocarbons including those containing up to about 40% by weight of vinyl aromatic hydrocarbon. Accordingly, multi-block copolymers may be utilized which are linear or radial symmetric or asymmetric and which have structures represented by the formulae A-B, A-B-A, A-B-A-B, B-A-B, (AB)0, 1, 2 . . . BA, etc., wherein A is a polymer block of a vinyl aromatic hydrocarbon or a conjugated diene/vinyl aromatic hydrocarbon tapered copolymer block, and B is a rubbery polymer block of a conjugated diene.
The block copolymers may be prepared by any of the well-known block polymerization or copolymerization procedures including sequential addition of monomer, incremental addition of monomer, or coupling techniques as illustrated in, for example, U.S. Pat. Nos. 3,251,905; 3,390,207; 3,598,887; and 4,219,627. As well known, tapered copolymer blocks can be incorporated in the multi-block copolymers by copolymerizing a mixture of conjugated diene and vinyl aromatic hydrocarbon monomers utilizing the difference in their copolymerization reactivity rates. Various patents describe the preparation of multi-block copolymers containing tapered copolymer blocks including U.S. Pat. Nos. 3,251,905; 3,639,521; and 4,208,356.
Conjugated dienes that may be utilized to prepare the polymers and copolymers are those containing from 4 to about 10 carbon atoms and more generally, from 4 to 6 carbon atoms. Examples include from 1,3-butadiene, 2-methyl-1,3-butadiene(isoprene), 2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-pentadiene, 1,3-hexadiene, etc. Mixtures of these conjugated dienes also may be used.
Examples of vinyl aromatic hydrocarbons which may be utilized to prepare the copolymers include styrene and the various substituted styrenes such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, alpha-methylstyrene, beta-methylstyrene, p-isopropylstyrene, 2,3-dimethylstyrene, o-chlorostyrene, p-chlorostyrene, o-bromostyrene, 2-chloro-4-methylstyrene, etc.
Many of the above-described copolymers of conjugated dienes and vinyl aromatic compounds are commercially available. The number average molecular weight of the block copolymers, prior to hydrogenation, is from about 20,000 to about 500,000, or from about 40,000 to about 300,000.
The average molecular weights of the individual blocks within the copolymers may vary within certain limits. In most instances, the vinyl aromatic block will have a number average molecular weight in the order of about 2000 to about 125,000, or between about 4000 and 60,000. The conjugated diene blocks either before or after hydrogenation will have number average molecular weights in the order of about 10,000 to about 450,000, or from about 35,000 to 150,000.
Also, prior to hydrogenation, the vinyl content of the conjugated diene portion generally is from about 10% to about 80%, or from about 25% to about 65%, particularly 35% to 55% when it is desired that the modified block copolymer exhibit rubbery elasticity. The vinyl content of the block copolymer can be measured by means of nuclear magnetic resonance.
Specific examples of diblock copolymers include styrene-butadiene (SB), styrene-isoprene (SI), and the hydrogenated derivatives thereof. Examples of triblock polymers include styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), alpha-methylstyrene-butadiene-alpha-methylstyrene, and alpha-methylstyrene-isoprene alpha-methylstyrene. Examples of commercially available block copolymers useful as the adhesives in the present invention include those available from Kraton Polymers LLC under the KRATON trade name.
Upon hydrogenation of the SBS copolymers comprising a rubbery segment of a mixture of 1,4 and 1,2 isomers, a styrene-ethylene-butylene styrene (SEBS) block copolymer is obtained. Similarly, hydrogenation of an SIS polymer yields a styrene-ethylene propylene-styrene (SEPS) block copolymer.
The selective hydrogenation of the block copolymers may be carried out by a variety of well known processes including hydrogenation in the presence of such catalysts as Raney nickel, noble metals such as platinum, palladium, etc., and soluble transition metal catalysts. Suitable hydrogenation processes which can be used are those wherein 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 described in U.S. Pat. Nos. 3,113,986 and 4,226,952. Such hydrogenation of the block copolymers which are carried out in a manner and to extent as to produce selectively hydrogenated copolymers having a residual unsaturation content in the polydiene block of from about 0.5% to about 20% of their original unsaturation content prior to hydrogenation.
In one embodiment, the conjugated diene portion of the block copolymer is at least 90% saturated and more often at least 95% saturated while the vinyl aromatic portion is not significantly hydrogenated. Particularly useful hydrogenated block copolymers are hydrogenated products of the block copolymers of styrene-isoprene-styrene such as a styrene-(ethylene/propylene)-styrene block polymer. When a polystyrene-polybutadiene-polystyrene block copolymer is hydrogenated, it is desirable that the 1,2-polybutadiene to 1,4-polybutadiene ratio in the polymer is from about 30:70 to about 70:30. When such a block copolymer is hydrogenated, the resulting product resembles a regular copolymer block of ethylene and 1-butene (EB). As noted above, when the conjugated diene employed as isoprene, the resulting hydrogenated product resembles a regular copolymer block of ethylene and propylene (EP).
A number of selectively hydrogenated block copolymers are available commercially from Kraton Polymers under the general trade designation “Kraton G.” One example is Kraton G1652 which is a hydrogenated SBS triblock comprising about 30% by weight of styrene end blocks and a midblock which is a copolymer of ethylene and 1-butene (EB). A lower molecular weight version of G1652 is available under the designation Kraton G1650. Kraton G1651 is another SEBS block copolymer which contains about 33% by weight of styrene. Kraton G1657 is an SEBS diblock copolymer which contains about 13% w 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: Bn(AB)oAp wherein n=0 or 1; o is 1 to 100; p is 0 or 1; each B prior to hydrogenation is predominantly a polymerized conjugated diene hydrocarbon block having a number average molecular weight of about 20,000 to about 450,000; each A is predominantly a polymerized vinyl aromatic hydrocarbon block having a number average molecular weight of from about 2000 to about 115,000; the blocks of A constituting about 5% to about 95% by weight of the copolymer; and the unsaturation of the block B is less than about 10% of the original unsaturation. In other embodiments, 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.
The block copolymers may also include functionalized polymers such as may be obtained by reacting an alpha, beta-olefinically unsaturated monocarboxylic or dicarboxylic acid reagent onto selectively hydrogenated block copolymers of vinyl aromatic hydrocarbons and conjugated dienes as described above. The reaction of the carboxylic acid reagent in the graft block copolymer can be effected in solutions or by a melt process in the presence of a free radical initiator.
The preparation of various selectively hydrogenated block copolymers of conjugated dienes and vinyl aromatic hydrocarbons which have been grafted with a carboxylic acid reagent is described in a number of patents including U.S. Pat. Nos. 4,578,429; 4,657,970; and 4,795,782, and the disclosures of these patents relating to grafted selectively hydrogenated block copolymers of conjugated dienes and vinyl aromatic compounds, and the preparation of such compounds. U.S. Pat. No. 4,795,782 describes and gives examples of the preparation of the grafted block copolymers by the solution process and the melt process. U.S. Pat. No. 4,578,429 contains an example of grafting of Kraton G1652 (SEBS) polymer with maleic anhydride with 2,5-dimethyl-2,5-di(t-butylperoxy) hexane by a melt reaction in a twin screw extruder.
Examples of commercially available maleated selectively hydrogenated copolymers of styrene and butadiene include Kraton FG1901X, FG1921X, and FG1924X, often referred to as maleated selectively hydrogenated SEBS copolymers. FG1901X contains about 1.7% by weight bound functionality as succinic anhydride and about 28% by weight of styrene. FG1921X contains about 1% by weight of bound functionality as succinic anhydride and 29% by weight of styrene. FG1924X contains about 13% styrene and about 1% bound functionality as succinic anhydride.
Useful block copolymers also are available from Nippon Zeon Co., 2-1, Marunochi, Chiyoda-ku, Tokyo, Japan. For example, Quintac 3530 is available from Nippon Zeon and is believed to be a linear styrene-isoprene-styrene block copolymer.
Unsaturated elastomeric polymers and other polymers and copolymers which are not inherently tacky can be rendered tacky when compounded with an external tackifier. Tackifiers, are generally hydrocarbon resins, wood resins, rosins, rosin derivatives, and the like, which when present in concentrations ranging from about 40% to about 90% by weight of the total adhesive composition, or from about 45% to about 85% by weight, impart pressure sensitive adhesive characteristics to the elastomeric polymer adhesive formulation. Compositions containing less than about 40% by weight of tackifier additive do not generally show sufficient “quickstick,” or initial adhesion, to function as a pressure sensitive adhesive, and therefore are not inherently tacky. Compositions with too high a concentration of tackifying additive, on the other hand, generally show too little cohesive strength to work properly in most intended use applications of constructions made in accordance with the instant invention.
It is contemplated that any tackifier known by those of skill in the art to be compatible with elastomeric polymer compositions may be used with the present embodiment of the invention. One such tackifier, found useful is Wingtak 10, a synthetic polyterpene resin that is liquid at room temperature, and sold by the Goodyear Tire and Rubber Company of Akron, Ohio. Wingtak 95 is a synthetic tackifier resin also available from Goodyear that comprises predominantly a polymer derived from piperylene and isoprene. Other suitable tackifying additives may include Escorez 1310, an aliphatic hydrocarbon resin, and Escorez 2596, a C5 to C9 (aromatic modified aliphatic) resin, both manufactured by Exxon of Irving, Tex. Of course, as can be appreciated by those of skill in the art, a variety of different tackifying additives may be used to practice the present invention.
In addition to the tackifiers, other additives may be included in the PSAs to impart desired properties. For example, plasticizers may be included, and they are known to decrease the glass transition temperature of an adhesive composition containing elastomeric polymers. An example of a useful plasticizer is Shellflex 371, a naphthenic processing oil available from Shell Lubricants of Texas. Antioxidants also may be included in the adhesive compositions. Suitable antioxidants include Irgafos 168 and Irganox 565 available from Ciba-Geigy, Hawthorne, N.Y. Cutting agents such as waxes and surfactants also may be included in the adhesives.
The pressure sensitive adhesive may be applied from a solvent, emulsion or suspension, or as a hot melt. The adhesive may be applied to the inner surface of the shrink film by any known method. For example, the adhesive may be applied by die coating curtain coating, spraying, dipping, rolling, gravure or flexographic techniques. The adhesive may be applied to the shrink film in a continuous layer, a discontinuous layer or in a pattern. The pattern coated adhesive layer substantially covers the entire inner surface of the film. As used herein, “substantially covers” is intended to mean the pattern in continuous over the film surface, and is not intended to include adhesive applied only in a strip along the leading or trailing edges of the film or as a “spot weld” on the film.
In one embodiment, an adhesive deadener is applied to portions of the adhesive layer to allow the label to more readily adhere to complex shaped articles. In one embodiment, non-adhesive material such as ink dots or microbeads are applied to at least a portion of the adhesive surface to allow the adhesive layer to slide on the surface of the article as the label is being applied and/or to allow air trapped at the interface between the label and the article to escape.
A single layer of adhesive may be used or multiple adhesive layers may be used. Depending on the shrink film used and the article or container to which the label is to be applied, it may be desirable to use 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 tack, peel strength and shear strength.
In one embodiment, the pressure sensitive adhesive has sufficient shear or cohesive strength to prevent excessive shrink-back of the label where adhered to the article upon the action of heat after placement of the label on the article, sufficient peel strength to prevent the film from label from lifting from the article and sufficient tack or grab to enable adequate attachment of the label to the article during the labeling operation. In one embodiment, the adhesive moves with the label as the shrink film shrinks upon the application of heat. In another embodiment, the adhesive holds the label in position so that as the shrink film shrinks, the label does not move.
The heat shrinkable film may include other layers in addition to the monolayer or multilayer heat shrinkable polymeric film. In one embodiment, a metalized coating of a thin metal film is deposited on the surface of the polymeric film. The heat shrinkable film may also include a print layer on the polymer film. The print layer may be positioned between the heat shrink layer and the adhesive layer, or the print layer may be on the outer surface of the shrink layer. In one embodiment, the film is reverse printed with a design, image or text so that the print side of the skin is in direct contact with the container to which the film is applied. In this embodiment, the film is transparent.
The labels of the present invention may also contain a layer of an ink-receptive composition that enhances the printability of the polymeric shrink layer or metal layer if present, and the quality of the print layer thus obtained. A variety of such compositions are known in the art, and these compositions generally include a binder and a pigment, such as silica or talc, dispersed in the binder. The presence of the pigment decreases the drying time of some inks. Such ink-receptive compositions are described in U.S. Pat. No. 6,153,288.
The print layer may be an ink or graphics layer, and the print layer may be a mono-colored or multi-colored print layer depending on the printed message and/or the intended pictorial design. These include variable imprinted data such as serial numbers, bar codes, trademarks, etc. The thickness of the print layer is typically in the range of about 0.5 to about 10 microns, and in one embodiment about 1 to about 5 microns, and in another embodiment about 3 microns. The inks used in the print layer include commercially available water-based, solvent-based or radiation-curable inks. Examples of these inks include Sun Sheen (a product of Sun Chemical identified as an alcohol dilutable polyamide ink), Suntex MP (a product of Sun Chemical identified as a solvent-based ink formulated for surface printing acrylic coated substrates, PVDC coated substrates and polyolefin films), X-Cel (a product of Water Ink Technologies identified as a water-based film ink for printing film substrates), Uvilith AR-109 Rubine Red (a product of Daw Ink identified as a UV ink) and CLA91598F (a product of Sun Chemical identified as a multibond black solvent-based ink).
In one embodiment, the print layer comprises a polyester/vinyl ink, a polyamide ink, an acrylic ink and/or a polyester ink. The print layer may be formed in the conventional manner by, for example, gravure, flexographic or UV flexographic printing or the like, an ink composition comprising a resin of the type described above, a suitable pigment or dye and one or more suitable volatile solvents onto one or more desired areas of the film. After application of the ink composition, the volatile solvent component(s) of the ink composition evaporate(s), leaving only the non-volatile ink components to form the print layer.
The adhesion of the ink to the surface of the polymeric shrink film or metal layer if present can be improved, if necessary, by techniques well known to those skilled in the art. For example, as mentioned above, an ink primer or other ink adhesion promoter can be applied to the metal layer or the polymeric film layer before application of the ink. Alternatively the surface of the polymeric film can be corona treated or flame treated to improve the adhesion of the ink to the polymeric film layer.
Useful ink primers may be transparent or opaque and the primers may be solvent based or water-based. In one embodiment, the primers are radiation curable (e.g., UV). The ink primer may comprise a lacquer and a diluent. The lacquer may be comprised of one or more polyolefins, polyamides, polyesters, polyester copolymers, polyurethanes, polysulfones, polyvinylidine chloride, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, ionomers based on sodium or zinc salts or ethylene methacrylic acid, polymethyl methacrylates, acrylic polymers and copolymers, polycarbonates, polyacrylonitriles, ethylene-vinyl acetate copolymers, and mixtures of two or more thereof. Examples of the 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 is dependent on the viscosity required for application of the ink primer, the selection of such viscosity being within the skill of the art. The ink primer layer may have a thickness of from about 1 to about 4 microns or from about 1.5 to about 3 microns.
A transparent polymer protective topcoat or overcoat layer may be present in the labels applied in accordance with the invention. The protective topcoat or overcoat layer provide desirable properties to the label before and after the label is affixed to a substrate such as a container. The presence of a transparent topcoat layer over the print layer may, in some embodiments provide additional properties such as antistatic properties stiffness and/or weatherability, and the topcoat may protect the print layer from, e.g., weather, sun, abrasion, moisture, water, etc. The transparent topcoat layer can enhance the properties of the underlying print layer to provide a glossier and richer image. The protective transparent protective layer may also be designed to be abrasion resistant, radiation resistant (e.g, UV), chemically resistant, thermally resistant thereby protecting the label and, particularly the print layer from degradation from such causes. The protective overcoat may also contain antistatic agents, or anti-block agents to provide for easier handling when the labels are being applied to containers at high speeds. The protective layer may be applied to the print layer by techniques known to those skilled in the art. The polymer film may be deposited from a solution, applied as a preformed film (laminated to the print layer), etc.
When a transparent topcoat or overcoat layer is present, it may have a single layer or a multilayered structure. The thickness of the protective layer is generally in the range of about 12.5 to about 125 microns, and in one embodiment about 25 to about 75 microns. Examples of the topcoat layers are described in U.S. Pat. No. 6,106,982.
The protective layer may comprise polyolefins, thermoplastic polymers of ethylene and propylene, polyesters, polyurethanes, polyacryls, polymethacryls, epoxy, vinyl acetate homopolymers, co- or terpolymers, ionomers, and mixtures thereof.
The transparent protective layer may contain UV light absorbers and/or other light stabilizers. Among the UV light absorbers that are useful are the hindered amine absorbers available from Ciba Specialty Chemical under the trade designations “Tinuvin”. The light stabilizers that can be used include the hindered amine light stabilizers available from Ciba Specialty Chemical under the trade designations Tinuvin 111, Tinuvin 123, (bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate; Tinuvin 622, (a dimethyl succinate polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidniethanol); Tinuvin 770 (bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate); and Tinuvin 783. Additional light stabilizers include the hindered amine light stabilizers available from Ciba Specialty Chemical under the trade designation “Chemassorb”, especially Chemassorb 119 and Chemassorb 944. The concentration of the UV light absorber and/or light stabilizer is in the range of up to about 2.5% by weight, and in one embodiment about 0.05% to about 1% by weight.
The transparent protective layer may contain an antioxidant. Any antioxidant useful in making thermoplastic films can be used. These include the hindered phenols and the organo phosphites. Examples include those available from Ciba Specialty Chemical under the trade designations Irganox 1010, Irganox 1076 or Irgafos 168. The concentration of the antioxidant in the thermoplastic film composition may be in the range of up to about 2.5% by weight, and in one embodiment about 0.05% to about 1% by weight.
A release liner may be adhered to the adhesive layer to protect the adhesive layer during transport, storage and handling prior to application of the label to a substrate. The liner allows for efficient handling of an array of individual labels after the labels are die cut and the matrix is stripped from the layer of facestock material and up to the point where the individual labels are dispensed in sequence on a labeling line. The release liner may have an embossed surface and/or have non-adhesive material, such as microbeads or printed ink dots, applied to the surface of the liner.
The preferred label applicator systems in accordance with the present invention generally comprise a first assembly of a belt and a collection of rollers, and a corresponding second assembly of a belt and a collection of rollers. In each of the first and second assemblies, the belt extends around at least some of the rollers and preferably, around all of the rollers. The first and the second assemblies are arranged relative to one another such that a portion of the first belt and a portion of the second belt are generally aligned with one another to define an article receiving lane between the portion of the first belt and the portion of the second belt. In accordance with a significant feature of the present invention, the lane extends in at least two different directions. Typically, the number of occurrences in change in direction of the lane ranges from at least two to six or more, hence the term “zig-zag” configuration is used to refer to the configuration resulting from the arrangement of the first and second assemblies of belts and rollers.
Preferably, each of the first and second assemblies is similar to one another and utilize the same number and types of belts and rollers. Most preferably, the two assemblies are symmetrical with respect to one another as explained herein. However, it will be appreciated that in no way is the invention limited to the use of symmetrical assemblies. Instead, the invention includes the use of assemblies that are non-symmetrical and/or different from one another.
Each assembly preferably comprises a collection of rollers that includes at least one drive roller and at least two lane-defining rollers. Thus, the first assembly includes one or more drive rollers and at least two lane-defining rollers. And the second assembly includes one or more drive rollers and at least two lane-defining rollers.
Preferably, the two assemblies are arranged such that one of the lane-defining rollers of the first assembly is positioned between two of the lane-defining rollers of the second assembly; and one of the lane-defining rollers of the second assembly is positioned between two of the lane-defining rollers of the first assembly. However, it will be appreciated that the present invention includes a wide range of other arrangements and configurations for the assemblies and/or their various rollers and belts.
As noted, upon appropriate arrangement of the first and second assemblies, an article receiving lane is defined between portions of the belts of the two assemblies. The lane includes an article entrance location generally upstream in the resulting system and a corresponding article exit location downstream. The lane preferably is formed or otherwise defined between portions of two belts. As explained in greater detail herein, the belts are arranged relative to one another such that upon motion of the belts, once an article is brought into contact between the belts, the article is contacted by belts on opposing sides of the article. The belts each exhibit a deformable characteristic along their article-contacting face. Preferably, the belt portions forming the lane are generally parallel to one another and spaced apart such that areas of the belts contacting the article are deformed, thereby engaging and retaining the article captured therebetween.
In a preferred aspect, the lane undergoes at least two changes in direction as previously noted, and thus is generally described herein as having a zig-zag configuration. The extent of directional change can be expressed relative to an axis along which the lane-defining rollers are positioned. Preferably, each change in direction ranges from about 5° to about 45°, more preferably from about 10° to about 35°, and most preferably from about 20° to about 25°. Preferably, the lane undergoes alternating changes in direction and so the net change in direction over the entire lane is typically less than 10°. Most preferably, the total angular change in direction that the lane undergoes between the article entrance location and the article exit location sums to less than 5°. For example, if the lane undergoes a first change in direction of 30° and then a second change in direction of −30° (the negative sign denoting that the second change in direction is opposite that of the first change in direction), then the net change in direction is 0°. Thus, articles exiting the lane are traveling in generally the same direction as they were traveling upon initially entering the lane. However, it will be understood that the present invention includes systems in which articles exiting the lane are traveling in a significantly different direction than the direction of articles entering the lane.
Additional details and aspects are now provided concerning the rollers and belts of the noted assemblies. The rollers are not limited to any particular size or shape. However, generally the rollers are cylindrical in shape and from about 46 cm (about 18 inches) to about 15 cm (about 6 inches), more preferably from about 38 cm (about 15 inches) to about 23 cm (about 9 inches), and most preferably about 30 cm (about 12 inches) in diameter. The rollers are preferably rotatable about a vertical axis, and so their cross sectional shape taken along a horizontal plane is circular. Sufficiently sized rollers, e.g. having diameters of at least about 15 cm (about 6 inches), have been found to protect the belt backing material. If instead relatively small diameter rollers are used, such as having a diameter of less than about 10 cm (about 4 inches), significant stress is placed upon the belt backing material which can lead to material fatigue, excessive wear, and failure of the belt. The height of the rollers is generally greater than the width of the corresponding belt, although the invention includes the use of rollers with significantly different proportions. All rollers in an assembly preferably have the same height. Preferably, the rollers, or at least their outer surface, are formed from durable and wear-resistant materials that exhibit a relatively high degree of engagement upon contact with a belt. As will be appreciated, this characteristic minimizes efficiency losses resulting from slippage between the rollers and belt.
The belts are preferably flexible, strong, durable, and wear-resistant. A multilayer belt construction is preferably used as described in greater detail herein. A significant feature of the belts is that the side of the belt that contacts the article(s) to be directed through the label applicator system, is deformable. Generally, this deformable layer is a flexible cellular material such as a foamed polymeric material. Preferably, the foam is a closed cell foam, and is resistant to relatively high temperatures. The deformable layer is compressible upon application of a force. Preferably, the deformable layer for use in the belts of the present invention system can be compressed to 75% of its uncompressed height upon application of a pressure of from about 13.8 kilopascals (about 2 psi) to about 34.5 kilopascals (about 5 psi). Generally, the deformable layer used in the preferred belts satisfies the requirements of ASTM D-1056 2D1. The deformable layer of the belts preferably, also exhibits a 50% compression set after 22 hours at 100° C. (212° F.), in accordance with ASTM D-1056. The foamed polymeric material can be formed from a medium density silicon based foamed polymer exhibiting relatively high heat resistance. The thickness of the deformable layer may range from about 0.6 cm (about 0.25 inches) to 2.5 cm (about 1.0 inch) thick, with 1.3 cm (0.5 inches) being preferred.
As noted, the belts preferably have a multilayer configuration. The article-contacting side of the belt is deformable as previously described. The roller-contacting side of the belt is flexible, wear-resistant, and exhibits a relatively high tensile strength. The layer providing the roller-contacting side of the belt is generally referred to herein as a belt substrate. The roller-contacting side of the belt or belt substrate is preferably formed from a fiberglass silicon layer. A wide array of belt configurations and constructions can be utilized. Generally, all preferred belts used in the present invention systems include a belt substrate layer for contacting and engaging one or more rollers, and a deformable layer for contacting and engaging article(s) and/or label(s) or other components to be attached. The preferred embodiment belts may also include one or more layers or other components as desired. For example, one or more strength promoting layers may be included in the belts. In addition, if further increased conformance of the belt to article(s) is desired, it is contemplated that additional conformable layers could be incorporated in the belts.
The previously described first and second assemblies of rollers and belts are each independently controllable such that the belt speed of the first assembly can be independently controlled with regard to that of the second assembly, and vice versa. Generally for certain methods and systems described herein, during operation it is preferred that the belt speeds of the two assemblies are identical or at least within 10%, more preferably within 5%, and most preferably within 2% of each other. Belts that are operating at such velocities are referred to herein as having velocities that are “substantially the same.” However, the present invention includes operating the two assemblies at different belt velocities. For example, depending upon the application, article configuration, and label placement, the belts of the opposing assemblies can be operated at different speeds. This may be desired, for example, to selectively rotate or partially rotate one or more, or all of the articles traveling between the belts through the lane.
The label applicator system of the present invention preferably includes one or more heaters for heating the label(s) and/or articles or portions thereof. As previously explained, such heating may be utilized to induce shrinking of heat-shrink label material, initiate or accelerate adhesive cure, and/or otherwise promote affixment of the label of interest to an article such as a container. Preferably, heating is provided by radiant heaters such as infrared lamps. The present invention includes other modes of heating such as for example heating by forced hot air and heating by use of electrically resistant elements proximate or in contact with the articles and/or labels. Preferably, one or more heaters are arranged and/or positioned proximate to the belts such that the belts reach a steady-state temperature as measured proximate the article entrance location of the lane during operation of the assemblies of at least 50° C. (122° F.). This temperature ensures that for a typical residence time of article and label in the system and for a typical heat activated label or adhesive, the articles and/or labels are sufficiently heated. It will be appreciated that the particular temperature to which the belts, articles, and/or labels are heated will vary depending upon the particular process, label, and/or adhesive requirements.
The present invention is not limited to assemblies of rollers and belts arranged to provide a zig-zag configuration for the lane. Instead, although less preferred, the present invention includes a system of two or more assemblies in which the portions of opposed belts are oriented parallel to one another or substantially so to define relatively straight lanes. Moreover, it is also contemplated that arrangements could provide lanes that extended in an arcuate path.
The present invention also provides various methods for applying labels onto articles using the assemblies and systems described herein. Preferably, the methods utilize a system including a first assembly of a first belt extending about a first collection of rollers, and a second assembly of a second belt extending about a second collection of rollers. The first and second assemblies are arranged such that a portion of the first belt and a portion of the second belt are aligned with one another to define an article receiving lane. The method generally comprises initially adhering a label onto an outer surface of an article to receive the label. The method also comprises moving the first belt about the first collection of rollers and moving the second belt about the second collection of rollers such that the first and second belts are generally displaced alongside one another within the lane. And, the method further comprises introducing the article and label initially adhered thereto at a first location in the lane such that the first and second belts contact and transport the article and label to a second location in the lane. The second location is located downstream of the first location. As the article is transported from the first location to the second location and engaged between the two deformable belts, the label is fully contacted with and applied onto the article.
In the previously described method, the lane may be in a variety of different configurations. For example, the lane may be relatively straight or extend in an arcuate fashion. Most preferably, the lane extends in at least two different directions, i.e. in a zig-zag configuration.
In all of the noted methods, the assemblies are selectively controlled such that the velocity of the belts is controlled. Specifically, depending upon the lane configuration and desired pattern of article movement through the lane, the velocities of the belts can be controlled so as to be different or to be the same or substantially the same as one another.
Furthermore, in all of the methods, one or more heating operations can be undertaken to provide specified amounts of heat to the belts, articles, and/or labels prior to or during label application.
The second assembly 110 includes a drive roller 120 and two or more lane-defining rollers 130a and 130b. The second assembly 110 may also optionally include one or more secondary rollers 140, such as 140a and 140b. The second assembly 110 includes a belt 150 extending about the collection of rollers 120, 130a, 130b, 140a, and 140b.
Referring further to
Referring further to
The system 1 is depicted in
The present invention includes additional belt constructions such as the incorporation of one or more additional layers in the belt laminate. For example,
The present invention also includes the use of a wide array of different lane configurations besides the zig-zag configuration depicted in
Furthermore, it will be appreciated that the various arcuate lane configurations are not limited to a lane or lane segment extending through an arc of 90° as shown in
Although the present invention and its various preferred embodiments have been described in terms of applying labels, and particularly pressure sensitive shrink labels, onto curved surfaces of containers, and most preferably outwardly extending compound curved surfaces, it will be understood that the present invention is applicable to a host of other operations such as applying labels, films, or other thin flexible members upon other surfaces besides those associated with containers. Moreover, it is also contemplated that the invention can be used to apply such components onto relatively flat planar surfaces.
Additional details associated with applying pressure sensitive labels, and particularly pressure sensitive shrink labels, are provided in WO 2008/124581; US 2009/0038736; and US 2009/0038737.
Many other benefits will no doubt become apparent from future application and development of this technology.
All patents, published applications, and articles noted herein are hereby incorporated by reference in their entirety.
As described hereinabove, the present invention solves many problems associated with previous type devices. However, it will be appreciated that various changes in the details, materials and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art without departing from the principle and scope of the invention, as expressed in the appended claims.
The present application claims priority upon U.S. provisional Ser. No. 61/299,151 filed on Jan. 28, 2010, which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US11/21968 | 1/21/2011 | WO | 00 | 7/30/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61299151 | Jan 2010 | US |
