Digitally Printed Labels

Abstract

Primer coatings, overprint varnishes, and seaming solutions are described for application to substrates, such as wrap-around and sleeve labels used for labeling containers, particularly those used to make shrink-wrap labels. Labels can be digitally printed with or without lane priming. Using certain seaming solutions, the labels can be removed during a washing step, allowing the container to be recycled.

Description

[Background technology]

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 818,809, filed March 15, 2019, which is incorporated by reference in its entirety for all purposes.

[0002] Digital printing is a printing process in which the printed image is created directly from digital data, avoiding the use of "analog" intermediate media. Among other uses, digital printing is used to digitally create page and print elements. These items include, for example, one or more of the following: digitally created text, layout, and images. Unlike traditional printing processes, digital printing does not require intermediate pre-press processes between the digital document file and the final print. For example, among those that are not required are film, imagesetters, plates, plate setters, photochemicals, and other analog elements. Also, no press preparation is required, no plate mounting, no registration adjustments, no ink keys, and no waste.

[0003] Printing on demand digital presses utilizing liquid electrophotographic systems is now widespread, in which a liquid toner image is formed on a photoconductive drum and then electronically transferred onto an intermediate transfer blanket or belt for printing onto paper, polymeric film sheets, or webs.

[0004] Liquid toners may be used in electrostatic digital printers. One such liquid toner is described in U.S. Patent No. 5,407,771. Printers using such liquid toners are commercially available from Hewlett-Packard Company under the trade name HP Indigo. Liquid toners typically do not transfer well or adhere well to paper or polymeric films unless they are treated with a coating or primer to enhance the adhesion of the liquid toner (also called "optimized").

[0005] Coatings and primers have been developed that make the surface of paper or polymer film more compatible with liquid toner inks. For example, they improve the printing and adhesion of liquid toner inks to the substrate on which the coating or primer is applied. However, problems can occur when such coatings or primers are applied to digitally printed shrink films where the edges of the film are overlapped to form a seam that is welded closed with a seaming solution, also known as a seam welding solvent. Such films are formed into sleeves and shrunk to fit the outside of articles such as plastic containers filled with food, beverages, household cleaning products, automotive fluids, and the like. The films are printed with text, images, logos, and the like to provide a label for the substance packed within the container. In such shrink wrap films, the adhesion in the seam formed by the seam welding solvent must be strong enough to hold the sleeve of shrink wrap film around the container after shrinking, and the adhesion must be maintained throughout the useful life of the article (e.g., during the movement of the article from packaging to the point of commerce, and then at least until the contents of the article are consumed or discarded).

[0006] Some seaming solvents may impair seaming and sleeve formation because they cannot penetrate the primer layer. Therefore, the seaming area must be kept free of primer (as well as any other coatings such as prints and varnishes). This problem may be addressed by selective priming, or "lane priming," where a 4-7mm wide area extending inward from the edge of the label is left unprimed to allow a good seam to form. However, with lane priming, there is no primer in the seam area, making it difficult and perhaps impossible to print in this area with liquid toner inks since there is no primer in this area.

[0007] Lane priming is typically performed using an analog printing process (e.g., flexography). Deviating from a fully digital printing process to incorporate an analog printing step adds additional time to the printing process. By eliminating the time-consuming lane priming, more of the printing process steps can be digitized, thereby reducing turnaround time, increasing productivity, and providing more design flexibility.

[0008] The number of plastic containers being recycled has been increasing for some time. While plastic containers are recyclable, the shrink label material used to label the containers is often not recyclable. Thus, to enable recycling of the plastic containers, it is necessary to remove the shrink wrap label from the plastic container or separate the label material from the container material. If the label is not easily separable from the container, many containers that would otherwise be recycled are not recycled, thereby reducing recycling recovery rates. Thus, there is a need to produce easily separable labels to increase the efficiency of recycling.

[0009] Guidelines from The Association of Plastics Recyclers, brand owners, and publications from the National Association for PET Container Resources (NAPCOR) have all pointed to the problems created by full-body sleeve labels within the recycling system. Sleeves tend to impair automated detection systems during the sorting process. As a result, PET recycling facilities see reduced recovery rates as sleeved bottles tend to end up being separated from the clear PET containers and discarded. It would therefore be advantageous if sleeve labels could be removed relatively quickly, for example, within 15 minutes of exposure to a hot aqueous solution containing a corrosive substance such as NaOH (e.g., a 1.0 wt % NaOH solution at 75° C.), and more preferably within 10 minutes under these conditions.

[0010] To mitigate sorting issues, recyclers and brand owners may recommend the use of paper labels or partial sleeves made of low density thermoplastic materials such as polyolefins, however, such materials do not have the shrink properties or printability desired for higher density substrates such as PET-G.

[0011] Separation of shrink sleeves from plastic containers, such as PET containers, is typically accomplished in a sink / flotation tank as part of an overall recycling process, e.g., bales of PET containers are converted into clear recycled PET (R-PET) flakes that are reused for container fabrication.

[0012] Several film / resin suppliers, including Exxon, Toppas, Cryovac, or converters such as Fujiseal, have introduced low density films or low density (<1.0 or at least <1.05) coextruded film structures to address shrink sleeve separation issues. Such films are generally based on a single or multi-layer structure containing a polymer built around a low density core such as a polyolefin, or a micro-voided / cavitated polymer, optionally wrapped by a PET-G skin and, if necessary, a tie layer between the core and the PET-G. The overall density of the film is designed to make it floatable in a sink / flotation tank. However, if the pre-printing density is not low enough, the printed sleeve may be too dense to be separated from the PET container to be recycled. Furthermore, labels made from low density films cannot cover more than 80% of the container or else automated detection systems would be compromised during the sorting process. Ideally, the shrink sleeve should cover up to 100% of the container, thereby maximizing artwork and text and providing 360 degree design flexibility.

[0013] Thus, there remains a need in the art for a primer or coating used in combination with a seaming solution that provides good adhesion to the primer and / or coating without the need for lane priming. With certain seaming solutions, the seamed shrink sleeve will fray during the washing stage, allowing for recycling of the container.

[0014] Additionally, there is a need for a seaming solution that provides sufficient adhesive strength within the seam of a shrink wrap label and is compatible with the primer composition applied to the substrate.

[0015] For example, digital printing presses with one or more printing stations, where inks, primers, and other compositions are digitally printed onto a substrate, have improved printing operations. For example, prints can be prepared in-line, i.e., by transfer from printing station to printing station on a single digital printing press, such as, for example, a commercially available printing press known as an HP Indigo press. The printing stations can be different color stations or can be used to print different printing compositions, such as primer compositions and ink compositions. The HP Indigo press uses liquid electrophotography to print with liquid inks known as HP Electroink®, which contain charged particles dispersed in a liquid. After charging a photoconductor, a laser image is created by a multi-laser scanning unit. The ink is developed onto the latent image by one of several color ink developing stations. After the ink is transferred to the blanket using an electric field, the carrier liquid evaporates from the hot blanket, and the remaining hot molten ink film is transferred to the substrate by pressure and viscosity. This process is repeated at each color station. See, for example, Taganksy, HP-Indigo Technology and its Application to Photo Printing, International Symposium for Digital Photo Fulfillment, pp. 31-34, (2012).

[0016] The disclosed invention not only provides better adhesive strength on digitally printed shrink labels with lane priming, but also enables flood coating and seaming on printed digital labels for the first time.

[0017] Potential references of interest include U.S. Patent Nos. 5,407,771, 6,881,458, 7,470,736, 7,985,483, 8,198,353, 9,175,172, and 9,976,057, and U.S. Patent Application Publication No. 2017 / 0174927. Summary of the Invention

[0018] Described herein is a primer composition for application to substrates used in labeling of merchandise, such as containers for various items. The primer promotes and enables printability of substrates that have shown difficulties when used in digital printing operations, such as printing the substrate with liquid toners used in digital printing operations. Additionally, the primer composition does not interfere with the ability of the seaming solution to form a sufficiently strong bond to attach the label to the substrate. This includes forming a sufficiently strong bond within the seam area of ​​a shrink-wrap label where the substrate is formed into a cylindrical loop, such as, for example, one made of a heat shrinkable substrate, PET or PET-G, where the substrate is shrunk to fit the size and dimensions of the article. In other words, the entire substrate may be coated with the primer in a digital printing process, and the primer composition will not interfere with the ability of the seaming solution to form a sufficiently strong bond.

[0019] Also described herein are overprint varnishes and seaming solutions that may be used alone, in combination with each other, and in combination with the primer composition.

[0020] Also described herein are primed substrates.

[0021] Provided herein is a method of preparing a substrate for labeling of an article, comprising applying a primer composition to the substrate, without lane priming; A method is described in which the primer composition comprises 60% to 95% by weight of an aqueous polyurethane dispersion and 5.0% to 40% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers, and preferably 65% ​​to 85% by weight of the aqueous polyurethane dispersion and 15% to 35% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers.

[0022] In one embodiment, the primer composition is applied by a process selected from digital printing, inkjet, offset, flexographic, lithographic, gravure, screen printing, roll coating, spray coating, and die coating.

[0023] In one embodiment, the liquid toner ink composition is applied over the primer composition.

[0024] In one embodiment, the liquid toner ink composition is applied by digital printing.

[0025] In one embodiment, the primer composition is applied by digital printing.

[0026] In one aspect, the primer composition promotes adhesion of the liquid toner ink composition to a polymeric substrate.

[0027] In one embodiment, the substrate is a heat shrinkable polymer substrate.

[0028] In one aspect, the heat shrinkable polymeric substrate is suitable for use in forming a shrink sleeve label for an article.

[0029] In one embodiment, the substrate is selected from paper, art paper, coated paper, paperboard, polymeric films, and nonwoven fabrics.

[0030] In one embodiment, the substrate is a polymer film selected from polyethylene terephthalate, polyethylene terephthalate glycol, polybutylene terephthalate, polycarbonate, polyolefin, cyclic polyolefin, α-polyolefin, polyethylene, polypropylene, oriented polypropylene, polystyrene, oriented polystyrene (OPS), polyvinyl chloride, and nylon.

[0031] In one embodiment, the primer composition is applied on at least one edge of the polymeric substrate in a location that is within 7 mm of at least one edge, preferably within 6 mm of at least one edge, more preferably within 5 mm of at least one edge, and even more preferably within 4 mm of at least one edge.

[0032] In one embodiment, the primer composition is applied on at least two edges of the polymeric substrate in a location that is within 7 mm of the at least two edges, preferably within 6 mm of the at least two edges, more preferably within 5 mm of the at least two edges, and even more preferably within 4 mm of the at least two edges.

[0033] In one aspect, the primer composition is applied to the edges of the polymeric substrate in the seaming area without leaving an unprimed area on the edges of the polymeric substrate in the seaming area.

[0034] In one embodiment, the seaming solution contacts and overlaps the primer composition.

[0035] In one embodiment, an overprint varnish is applied over the liquid toner ink composition, the overprint varnish comprising 10% to 90% by weight of the (meth)acrylic copolymer and 10% to 90% by weight of gum rosin, and preferably 25% to 75% by weight of the (meth)acrylic copolymer and 25% to 75% by weight of the gum rosin.

[0036] In one embodiment, at least one of the application of the primer composition, the application of the liquid toner ink composition, the application of the overprint varnish, and the application of the seaming solution is performed in-line on a digital printing press.

[0037] In one embodiment, at least two of the application of the primer composition, the application of the liquid toner ink composition, the application of the overprint varnish, and the application of the seaming solution are performed in-line on a digital printing press.

[0038] In one embodiment, the applied seaming solution contacts and overlaps the applied primer composition.

[0039] Provided herein is a method of preparing a shrink-wrap label for labeling an article, comprising the steps of: applying a primer composition to the heat shrinkable polymeric substrate without lane priming, the primer composition comprising 60% to 95% by weight of an aqueous polyurethane dispersion and 5.0% to 40% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers, preferably 65% ​​to 85% by weight of the aqueous polyurethane dispersion and 15% to 35% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers; applying a liquid toner ink composition to a substrate; applying a seaming solution onto at least one edge of a substrate; Positioning a substrate around a shaped article; forming a seam of contacting edges of a substrate, one of the contacting edges being at least one edge to which a seaming solution is applied, thereby forming a bond in the seam; and shrinking the substrate to the shape of the article.

[0040] In one aspect, the contacting edges of the substrates that form the seam overlap one another.

[0041] The various aspects described above also apply to this method.

[0042] In one embodiment, the seaming solution comprises 0% to 50% by weight of a polyester resin or polyester resin blend and 50% to 100% by weight of one or more solvents, where the polyester resin or polyester resin blend is present, the glass transition temperature (Tg) of the polyester resin or polyester resin blend is preferably from about -10°C to about 50°C, and one of the solvents is a seam welding solvent. In one embodiment, the viscosity of the seaming solution is from 1 cP to 50 cP when measured at or near 25°C at 30 rpm on a Brookfield DV-2T viscometer with spindle SC4-18(18). The Tg of the polyester blend is the Tg value of the combined polyester resins. A polyester resin blend is a mixture of two or more polyester resins.

[0043] In one embodiment, the amount of polyester resin or polyester resin blend present in the seaming solution is from 1.0% to 50% by weight.

[0044] In one embodiment, the polyester resin blend is present in a seaming solution.

[0045] In one embodiment, the seaming solution creates a bond in the seam with a primer, and the seaming solution has a T peel strength of 20 gf or greater.

[0046] In one embodiment, the seaming solution produces a bond having an S tensile strength of 3,000 gf / inch or greater.

[0047] In one embodiment, a T peel strength of 20 gf or greater and / or an S tensile strength of 3,000 gf / inch or greater is achieved whether or not a primer and / or OPV as described herein is applied.

[0048] Further provided herein is a method of preparing a shrink-wrap label for labeling an article, comprising the steps of: A method is described which includes applying, without lane priming, a liquid toner ink composition to a heat shrinkable polymer substrate coated with a primer composition, the primer composition including 60% to 95% by weight of an aqueous polyurethane dispersion and 5.0% to 40% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid based monomers, preferably 65% ​​to 85% by weight of the aqueous polyurethane dispersion and 15% to 35% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid based monomers.

[0049] The various aspects described above also apply to this method.

[0050] Further described herein is a primer composition comprising 60% to 95% by weight of an aqueous polyurethane dispersion and 5.0% to 40% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers, and preferably 65% ​​to 85% by weight of an aqueous polyurethane dispersion and 15% to 35% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers.

[0051] In one embodiment, the polyurethane dispersion comprises (A) a polyisocyanate component, (B) a polyol component, and (C) an ionic or potentially ionic (-NH 3+ ) the underlying neutral charge (-NH 2 ) with an isocyanate-reactive component.

[0052] In one aspect, the polyisocyanate component of the polyurethane dispersion is selected from diisocyanates and diisocyanate reaction products containing urethane groups, urea groups, uretdione groups, uretonimine groups, isocyanurate groups, iminooxadiazinedione groups, oxadiazinetrione groups, carbodiimide groups, acylurea groups, biuret groups, allophanate groups, and combinations thereof.

[0053] In one embodiment, the polyisocyanate component is 4,4'-diisocyanatocyclohexylmethane, hexamethylene diisocyanate, 1-methyl-2,4(2,6)-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, norbornane diisocyanate, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, 4,4'-diisocyanatodiphenylmethane, xylylene diisocyanate. , tetramethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatododecane, 2,3,3-trimethylhexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexyl diisocyanate, α,α,α',α'-tetramethyl-m- or p-xylylene diisocyanate, triphenylmethane 4,4',4"-triisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate, and combinations thereof.

[0054] In one embodiment, the polyol component is selected from oligomeric or polymeric compounds having terminal hydroxyl groups, pendant hydroxyl groups, and combinations thereof.

[0055] In one embodiment, the polyol component is selected from polyether polyols, polyester polyols, polyacrylic polyols, polycarbonate polyols.

[0056] In one embodiment, the polyol component is selected from polyether polyols, polyester polyols, polyacrylic polyols, polycarbonate polyols including tetrahydrofuran, styrene oxide, propylene oxide, ethylene oxide, butylene oxide, epichlorohydrin, ethylene glycol, 1,2 propanediol, 1,3-propanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, bis-hydroxymethylcyclohexane, 2,2-bis-(4-hydroxyphenyl)propane, trimethylolpropane, glycerol, triethanolamine, pentaerythritol, tris-(2-hydroxyethyl)isocyanurate, and mixtures thereof.

[0057] In one embodiment, the isocyanate reactive groups are selected from 2,2-bis(hydroxymethyl)-alkanecarboxylic acids, dimethylolacetic acid, 2,2-dimethylol-propionic acid, 2,2 dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, hydroxypivalic acid, and combinations thereof.

[0058] In one embodiment, the polyurethane dispersion has a solids content of 5.0% to 55% by weight, preferably 20% to 40% by weight.

[0059] In one embodiment, the α-olefin component of the copolymer of one or more α-olefins and one or more acid-based monomers is selected from ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

[0060] In one embodiment, the acid-based monomer component of the aqueous dispersion of copolymers of one or more α-olefins and one or more acid-based monomers is selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, citraconic acid, citraconic anhydride, methyl hydrogen maleate, ethyl hydrogen maleate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutyl acrylate, methyl fumarate, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl chloride, vinylidene chloride, acrylamide, acrylonitrile, methacrylonitrile, fumaronitrile, derivatives thereof, and combinations thereof.

[0061] In one embodiment, the aqueous dispersion of copolymers of one or more α-olefins and one or more acid-based monomers is derived from ethylene, acrylic acid, methacrylic acid, and combinations of acrylic acid and methacrylic acid.

[0062] In one embodiment, the aqueous dispersion of the copolymer of one or more α-olefins and one or more acid-based monomers has a solids content of 10% to 60% by weight, preferably 30% to 50% by weight.

[0063] The described primer compositions eliminate the need for lane priming the label substrate when preparing labels for digital printing operations.

[0064] Recycling of containers having digitally printed shrink-wrap labels can also be accomplished through relatively quick removal of the label from the container.

[0065] Further described herein is a primed substrate comprising a primer composition applied to the substrate comprising 60% to 95% by weight of an aqueous polyurethane dispersion and 5.0% to 40% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers, and preferably 65% ​​to 85% by weight of the aqueous polyurethane dispersion and 15% to 35% by weight of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers.

[0066] The various aspects described above also apply to the primed substrates of the present invention.

[0067] In one aspect, the primer composition promotes adhesion of the liquid toner ink composition to a polymeric substrate.

[0068] Also described herein is a seaming solution for applying label substrates, including wrap-around labels such as shrink-wrap labels and sleeve labels, to containers. The labels can be digitally printed with or without lane priming. With certain seaming solutions, the labels can be removed during a wash step, allowing the container to be recycled.

[0069] The seaming solution described herein comprises 1.0% to 50% by weight of a polyester resin or polyester resin blend and 50% to 99% by weight of one or more solvents, where the polyester or polyester resin blend has a Tg of about -10°C to about 50°C, and one of the solvents is a seam welding solvent. In one embodiment, the seaming solution has a viscosity of 1 cP to 50 cP when measured at or near 25°C at 30 rpm on a Brookfield DV-2T viscometer with spindle SC4-18(18). The Tg of the polyester blend is the Tg value of the combined polyester resins.

[0070] In one embodiment, the seam welding flux is selected from tetrahydrofuran, 1,3-dioxolane, dioxane, n-hexane, cyclohexane, methylcyclohexane, methyl ethyl ketone, acetone, methyl isobutyl ketone, methyl acetate, methanol, isopropyl alcohol, and combinations thereof.

[0071] In one embodiment, the seam welding flux is selected from tetrahydrofuran, 1,3-dioxolane, methyl ethyl ketone, and combinations thereof.

[0072] In one aspect, one or both of the primer coating and seaming solution combination is at least partially hydrolyzable or soluble under the conditions of recycling.

[0073] In one aspect, a label sleeve for labeling a plastic container as described herein (i.e., coated with a primer and / or seaming solution as described herein) can be removed from the container when placed in a high-temperature caustic bath during a recycling process. For example, the sleeve can be removed by deseaming the sleeve label, which opens the endless loop in which the label was formed, thereby facilitating removal of the label from the article. That is, the seaming solution is soluble and / or partially hydrolyzable in the high-temperature caustic bath, which opens the seam and separates the label from the article when the article is placed in the high-temperature caustic bath.

[0074] The terms "hot caustic bath" and "hot caustic solution" are defined as a 1.0 wt % NaOH aqueous solution at a temperature of 75° C. These terms are used interchangeably herein.

[0075] The term "soluble in a hot caustic bath" is defined as 20% to 100% by weight soluble in 100 grams of hot caustic solution when 0.5 grams of solid resin is immersed in the hot caustic solution for 20 minutes, preferably 50% to 100% by weight soluble, and more preferably 80% to 100% by weight soluble in 100 grams of hot caustic solution.

[0076] The terms "solutionable," "solutioned," and "soluble" are used interchangeably herein.

[0077] The term "at least partially hydrolyzable in a hot caustic bath" is defined as having at least a portion of the hydrolyzable functional groups hydrolyzed in a hot caustic bath when immersed in the hot caustic bath for 20 minutes. Hydrolyzable functional groups include, for example, OH, -COOH, or -SO3H, which upon hydrolysis, deprotonate in the presence of a base (e.g., an alkaline or caustic solution) and undergo cation exchange. For example, in the presence of NaOH, H+ is exchanged for Na+, the M+ metal cation.

[0078] In one embodiment, an article is described that is wrapped with a shrink sleeve label to which one or more of the primer composition, OPV, and seaming solution as described above are applied.

[0079] In one embodiment, the label detaches when exposed to a hot caustic solution containing 1.0 wt % NaOH at 85° C. in less than 20 minutes.

[0080] In one embodiment, the label detaches when exposed to a hot caustic aqueous solution containing 1.0 wt % NaOH at 65° C. in less than 20 minutes.

[0081] In one embodiment, the label detaches when exposed to a hot caustic solution containing 1.0 wt % NaOH at 75° C. in less than 15 minutes.

[0082] In one embodiment, the label detaches in less than 10 minutes at 75° C. when exposed to a hot caustic solution containing 1.0% by weight NaOH.

[0083] In one embodiment, the label detaches when exposed to a hot caustic solution containing 1.0 wt % NaOH at 85° C. in less than 10 minutes.

[0084] The seaming solution of the present invention is preferably applied by a liquid dosing system such as a needle or felt wick. Other deposition methods such as roll, spray, die coating, or screen printing, flexography, gravure printing, etc. may be possible by adjusting the coating composition to the rheology required for proper deposition for the particular technique.

[0085] In one embodiment, the label is a full wrap label.

[0086] In another embodiment, the label is a partial wrap label.

[0087] In certain embodiments, the label is a shrink wrap label.

[0088] In one embodiment, the article is a plastic article.

[0089] In one aspect, the present disclosure is directed to sleeve labels prepared from the coatings described herein.

[0090] Also described herein is an overprint varnish.

[0091] Further described herein is an overprint varnish comprising 10% to 90% by weight of one or more (meth)acrylic homopolymers or (meth)acrylic copolymers and 10% to 90% by weight of one or more gum rosins, preferably 25% to 75% by weight of one or more (meth)acrylic homopolymers or (meth)acrylic copolymers and 25% to 75% by weight of one or more gum rosins.

[0092] In one embodiment, the one or more (meth)acrylic homopolymers or (meth)acrylic copolymers are the polymerization products of one or more alkyl acrylate monomers, aryl acrylate monomers, alkaryl (meth)acrylate monomers, acrylic acid and its esters, methacrylic acid and its esters, alcohols containing aliphatic or aromatic rings, with or without alcohols containing at least one heteroatom in addition to the oxygen atom in the alcohol group, and combinations thereof.

[0093] In one embodiment, the one or more (meth)acrylic homopolymers or (meth)acrylic copolymers are the polymerization product of one or more monomers selected from methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclohexyl (meth)acrylate, phenylethyl (meth)acrylate, phenylpropyl (meth)acrylate, acrylates of heterocyclic alcohols, furfuryl (meth)acrylate, and combinations thereof.

[0094] In one embodiment, the one or more (meth)acrylic homopolymers or (meth)acrylic copolymers comprise (meth)acrylic copolymers selected from (meth)acrylic copolymers, ethylene (meth)acrylic copolymers, styrene (meth)acrylic copolymers derived from (meth)acrylic acid, itaconic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, hydroxyethyl (meth)acrylate, and combinations thereof.

[0095] In one embodiment, the one or more (meth)acrylic homopolymers or (meth)acrylic copolymers are present in a dispersion having a solids content of from 30% to about 70% by weight, preferably from about 35 to about 65% by weight, and more preferably from about 40 to about 60% by weight.

[0096] In one embodiment, the one or more gum rosins are derived from acids selected from abietic acid, neoabietic acid, palustric acid, levopimaric acid, dihydroabietic acid, pimaric acid, isopimaric acid, and sandaracopimaric acid, and combinations thereof, with or without esterification with pentaerythritol, with or without reaction with maleic anhydride or fumaric acid.

[0097] In one embodiment, the one or more gum rosins are derived from maleic resins, maleic anhydride resins, fumaric resins, fumaric anhydride resins, and polyester resins from gum rosin raw materials.

[0098] It has been found that by using the primer compositions described herein (such as those in Example 1) and the seaming solutions described herein, label substrates, such as shrink sleeve label substrates, can cover 80% or more, such as 81% or more, and even 100% of the article that the substrate is labeling. This is in contrast to low density substrate films, which cannot cover 80% or more of the article. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0099] As used herein, the term "coating" includes, but is not necessarily limited to, a liquid composition that may be deposited on a substrate in a variety of ways, including, but not limited to, printing (including, but not limited to, analog or digital, inkjet, offset, flexographic, lithographic, gravure, screen printing, etc.), roll coating, spray coating, die coating, etc., and the term "seaming solution" or "seaming solvent" includes, but is not necessarily limited to, a liquid composition that is applied, typically by a liquid dosing system such as a needle or felt wick, to the edges of a shrink film to create a shrink sleeve label. Also provided are methods and processes for the application and use of the coatings of the present invention, as well as the articles produced.

[0100] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described.

[0101] Suitable substrates include, but are not limited to, paper (including art paper, coated paper, and paperboard), plastics, films, nonwovens, etc. Plastic substrates include polyethylene terephthalate (PET), polyethylene terephthalate glycol (PET-G), polybutylene terephthalate (PBT), polycarbonate, polyolefins, cyclic polyolefins (COC), and α-polyolefins such as polyethylene (PE), polypropylene (PP), oriented polypropylene (OPP), polystyrene, oriented polystyrene (OPS), polyvinyl chloride (PVC), nylon, etc. As used herein, "nonwoven" refers to substrates made from fibrous materials such as wood cellulose, cotton, rayon, PET, PBT, polyacrylonitrile, PP, etc. In a particular embodiment, the substrate is a PET-G shrink film.

[0102] The coating and seaming solution of the present invention allows for good seaming and resistance to cold water. Furthermore, because the seamed label is adhered to the container by shrinking the label, the seam formed from the seaming solution remains intact and retains sufficient adhesive strength despite shrinkage of the label (in this sense, the seaming solution is shrink-resistant). The container may be constructed of plastic, glass, metal, or other materials.

[0103] In one aspect, the coating of the present invention, when seamed with the seaming solution of the present invention, promotes good adhesion at the seam and facilitates subsequent removal for recycling of the container. The coating and seaming solutions of the present invention are useful for coating labels, including wrap-around and sleeve labels, particularly shrink-wrap labels, that are applied to plastic containers, while allowing for efficient deseaming and removal of the label during the recycling process.

[0104] Polyurethane Polymer The polyurethane polymer may comprise the reaction product of (A) a polyisocyanate component, (B) a polyol component, and (C) an isocyanate-reactive component that contains ionic or potentially ionic groups. As used herein, the term "polyisocyanate" refers to a compound that contains at least two unreacted isocyanate groups. Polyisocyanates include, for example, diisocyanates and diisocyanate reaction products that contain urethane, urea, uretdione, uretonimine, isocyanurate, iminooxadiazinedione, oxadiazinetrione, carbodiimide, acylurea, biuret, and / or allophanate groups.

[0105] The polyisocyanate repeat unit in the polyurethane polymer may include an aliphatic or cycloaliphatic diisocyanate. Examples of polyisocyanate component (A) include, but are not limited to, 4,4'-diisocyanatocyclohexylmethane (HMDI), hexamethylene diisocyanate (HDI), 1-methyl-2,4(2,6)-diisocyanatocyclohexane, or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (IPDI), and mixtures thereof. Preferably, the polyisocyanate component is 4,4'-diisocyanatocyclohexylmethane (HMDI). In addition to aliphatic or cycloaliphatic diisocyanates, water-dilutable carboxyl or hydroxyl functional polyurethane dispersions may be prepared using norbornane diisocyanate (NBDI), 2,4- and / or 2,6-diisocyanatotoluene (TDI), 1-methyl-2,4- and / or -2,6-diisocyanatocyclohexane, and 4,4'-diisocyanatodiphenylmethane (MDI), xylylene diisocyanate, tetramethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatobutane, 1,3-diisocyanatobutane, 1,4-diisocyanatobutane, 1,5-diisocyanatobutane, 1,6-diisocyanatobutane, 1,7-diisocyanatobutane, 1,8-diisocyanatobutane, 1,9-diisocyanatobutane, 1,10-diisocyanatobutane, 1, ...2-diisocyanatobutane, 1,3-diisocyanatobutane, 1,4-diisocyanatobutane, 1,5-diisocyanatobutane, 1,6-diisocyanatobutane, 1,7-diisocyanatobutane, 1,8-diisocyanatobutane, 1,9-diisocyanatobutane, 1,2-di Other polyisocyanates may also be included, such as anatododecane, 2,3,3-trimethylhexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexyl diisocyanate, α,α,α',α'-tetramethyl-m- or p-xylylene diisocyanate, triphenylmethane 4,4',4"-triisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate, as well as mixtures thereof.

[0106] In various non-limiting embodiments, the polyol component (B) may include an oligomeric or polymeric compound having terminal and / or pendant hydroxyl groups. Examples of polyol components include, but are not limited to, polyether polyol polyester polyols, polyacrylic polyols, polycarbonate polyols, or mixtures thereof, which may include diol, triol, or tetraol monomers. Examples of diol monomers include tetrahydrofuran, styrene oxide, propylene oxide, ethylene oxide, butylene oxide, epichlorohydrin, ethylene glycol, 1,2 propanediol, 1,3-propanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, bis-hydroxymethylcyclohexane isomers, and 2,2-bis-(4-hydroxyphenyl)propane. Examples of triol monomers include trimethylolpropane (TMP), glycerol, and triethanolamine. In one embodiment, pentaerythritol or tris-(2-hydroxyethyl)isocyanurate (THEIC) is used as the tetraol monomer.

[0107] In various non-limiting embodiments, the isocyanate-reactive group (C) may include at least one ionic or potentially ionic group, which may be either cationic or anionic in nature. The isocyanate-reactive component (C) may also include at least one isocyanate-reactive group, such as a hydroxyl group and / or an amine group. Examples of isocyanate-reactive groups (C) include, but are not limited to, 2,2-bis(hydroxymethyl)-alkanecarboxylic acids (such as dimethylolacetic acid, 2,2-dimethylol-propionic acid, 2,2-dimethylolbutyric acid, or 2,2-dimethylolpentanoic acid), dihydroxysuccinic acid, hydroxypivalic acid, and mixtures thereof.

[0108] Bases can be used to neutralize the carboxyl groups of polyurethane polymers to partially neutralize them. Bases include, but are not limited to, ammonia, N-methylmorpholine, dimethyl-isopropanolamine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, 2-diethylamino-2-methyl-1-propanol, and mixtures thereof, and / or other neutralizing agents. Sodium hydroxide, lithium hydroxide, and potassium hydroxide are also suitable as neutralizing agents, but are less preferred.

[0109] The solids content of the polyurethane dispersion is about 5 to 55% by weight, preferably about 20 to 40% by weight.

[0110] The viscosity of the polyurethane dispersion is about 5 cP to 5000 cP, preferably about 100 cP to 2000 cP.

[0111] Suitable commercially available polymer dispersions include U4000VP available from Alberdingk, WLS-201 from DIC, and Neorez R-600 from DSM.

[0112] Copolymers of one or more α-olefins and one or more acid-based monomers As used herein, "copolymer" refers to a polymer composed of two or more monomers. In various embodiments, the copolymer may include one or more α-olefins and one or more acid-based monomers. The α-olefin may be, by way of example and not limitation, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, or a combination thereof.

[0113] The acid-based monomers can be, by way of example and not limitation, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, and citraconic acid and anhydrides, methyl hydrogen maleate, ethyl hydrogen maleate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutyl acrylate, methyl fumarate, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl chloride, vinylidene chloride, acrylamide, acrylonitrile, methacrylonitrile, fumaronitrile, or combinations or derivatives thereof.

[0114] In some embodiments, the copolymer is obtained in the form of an aqueous emulsion.

[0115] In some embodiments, the copolymer comprises ethylene and acrylic acid or methacrylic acid.

[0116] The solids content of the copolymer emulsion is preferably about 10% to 60% by weight, more preferably about 30% to 50% by weight.

[0117] The viscosity of the copolymer emulsion is about 5 cP to 5000 cP, preferably about 100 cP to 2000 cP.

[0118] Commercially available copolymers of one or more α-olefins and one or more acid-based monomers include Cohesa X3060, Aquaseal™ 1307, Aquaseal™ 2077, and Aquaseal™ 2045 available from Paramelt.

[0119] Overprint Varnish According to another aspect of the present invention, the coating of the present invention is an overprint varnish (OPV) that is applied over one or both of the primer composition and the ink. The OPV provides one or more of improved chemical resistance, abrasion resistance, scratch resistance, and heat resistance. The OPV also controls the static and dynamic coefficient of friction (CoF) of the substrate in contact with other components (such as rollers on a printing press, substrates that contact other substrates for downstream conversion and processing, and between a label and an article (e.g., a container)). The CoF is a value related to the frictional force applied between two objects. A higher CoF means that more force is needed to overcome the frictional force to move one or both of the objects, and a high CoF between a substrate and another object can affect processing speed and can make the substrate and / or the coating thereon more susceptible to damage. On the other hand, if the CoF is too low, the objects can slip against each other, which can make processing more difficult. The OPVs described herein can both increase and decrease the CoF to overcome or avoid these problems.

[0120] Preferably, the composition of the overprint varnish described herein comprises, on a solids weight basis, 10-90% of one or more (meth)acrylic homopolymers or (meth)acrylic copolymers and 10-90% of one or more gum rosins.

[0121] Preferably, the composition of the overprint varnish described herein comprises, on a solids weight basis, 25-75% of one or more (meth)acrylic homopolymers or (meth)acrylic copolymers and 25-75% of one or more gum rosins.

[0122] As used herein, the terms "(meth)acrylate," "(meth)acrylic," "acrylate," "(meth)acrylic," and "acrylic" include both acrylic acid, methacrylic acid, acrylate compounds, and (meth)acrylate compounds, unless otherwise specified. In other words, these terms are used interchangeably and have the same meaning, unless otherwise specified.

[0123] The (meth)acrylic homopolymer or (meth)acrylic copolymer may be the polymerization product of one or more of alkyl acrylate monomers, aryl acrylate monomers, alkaryl (meth)acrylate monomers, acrylic acid and its esters, methacrylic acid and its esters, alcohols containing at least one heteroatom in addition to the oxygen atom in the alcohol group, and alcohols containing aliphatic or aromatic rings. Combinations thereof are also possible.

[0124] Exemplary acrylate monomers include, but are not limited to, methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclohexyl (meth)acrylate, phenylethyl (meth)acrylate, phenylpropyl (meth)acrylate, acrylates of heterocyclic alcohols, such as furfuryl (meth)acrylate, and combinations thereof. Additionally, the (meth)acrylic copolymers may include pure (meth)acrylic copolymers comprising at least one of (meth)acrylic acid, itaconic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, and hydroxyethyl (meth)acrylate, and the like, ethylene (meth)acrylic copolymers, and styrene (meth)acrylic copolymers.

[0125] In addition to the above, the (meth)acrylic homopolymers or (meth)acrylic copolymers may also contain polymerized groups derived from other monomers such as those having olefinic double bond(s) capable of undergoing free radical polymerization, including, but not limited to, vinyl ethers (such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and vinyl ethers with longer carbon chain lengths), vinyl esters (such as vinyl acetate and esters based on versatic acid), vinyl aromatics, nitriles, vinyl halides, hydrocarbons, such as, for example, vinyl laurate, vinyl stearate, vinyl propionate, vinyl acetate, vinyl toluene, α- and p-styrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, styrene, chlorine-, fluorine-, or bromine-substituted ethylenically unsaturated compounds, vinyl chloride, vinylidene chloride, 1,3-alkenes (such as butadiene, isoprene, and chloroprene), and combinations thereof.

[0126] In addition to the above, the (meth)acrylic homopolymer or (meth)acrylic copolymer may also contain polymerized groups derived from one or more styrenic monomers.Suitable styrenic monomers for use include those having substituted or unsubstituted phenyl groups attached to ethylene moieties.Styrenic monomers include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene, o-chlorostyrene, vinylpyridine, and combinations thereof.

[0127] In addition to the above, the (meth)acrylic homopolymer or (meth)acrylic copolymer may also contain polymerized groups derived from one or more carboxylic acid functional groups in the compound. Exemplary carboxylic acid functional monomers include, but are not limited to, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid. The term "carboxylic acid functional monomer" also includes anhydride derivatives of the carboxylic acid functional monomers listed above. The carboxylic acid functional monomer may include one, two, three, four, or more different carboxylic acid functional monomers.

[0128] In one embodiment, the (meth)acrylic homopolymer or (meth)acrylic copolymer is present in the OPV as an aqueous dispersion. The solids content of the dispersion can be from about 30% to about 70% by weight, preferably from about 35% to about 65% by weight, and more preferably from about 40% to about 60% by weight, based on the weight of the (meth)acrylic copolymer dispersion.

[0129] In one embodiment, the viscosity of the (meth)acrylic homopolymer or (meth)acrylic copolymer dispersion is from about 10 cP to about 3,000 cP, preferably from about 100 cP to about 2500 cP, and more preferably from about 200 cP to about 2000 cP.

[0130] Gum Rosin Gum rosin consists of organic acids such as abietic acid type, pimaric acid type, and their derivatives. Gum rosin acids include abietic acid, neoabietic acid, palustric acid, levopimaric acid, dihydroabietic acid, pimaric acid, isopimaric acid, and sandaracopimaric acid. Gum rosin is often used in modified forms. Gum rosin may be esterified, for example with pentaerythritol, to produce polyester resins. Gum rosin may be reacted with acids and / or anhydrides, such as maleic anhydride or fumaric acid, to produce modified renewable resins. Any gum rosin dispersion or solid may be used in the coatings described herein.

[0131] Renewable gum rosin materials that may be used in the OPV of the present invention are maleic, fumaric, and polyester resins derived from gum rosin raw materials. Other bio-renewable gum rosins may also be used. Suitable bio-renewable resins include, but are not limited to, Rokra-Kraemer's Erkamar 3275, Erkamar 3300, Erkamar 3266, and Erkamar 3270 (all maleic resins), Lawter's Reactol 5145A (polyester resin), HydroRez 3886 (fumaric resin), HydroRez 6200 (fumaric resin), and HydroRez 6500 (fumaric resin), combinations thereof, and the like. Ingevity's AltaRez 1042, 1043, and 1053 may also be used. Additionally, styrene acrylic emulsions such as Joncryl ECO2124, Joncryl ECO2189 from BASF, and Induprint 1831 from Indulor may be used.

[0132] In one embodiment, the gum rosin has a solids content of from about 20% to about 100% by weight, preferably from about 30% to about 100% by weight, and more preferably from about 35% to about 100% by weight, based on the weight of the rosin copolymer dispersion.

[0133] In one embodiment, the acid value of the gum rosin is within the range of about 10 to about 250, preferably within the range of about 30 to about 200, and more preferably within the range of about 50 to about 150.

[0134] In one embodiment, the melting temperature (Tm) of gum rosin is from about 10°C to about 250°C, preferably from about 30°C to about 200°C, and more preferably from about 50°C to about 150°C.

[0135] Crosslinking Agent In one embodiment, a crosslinking agent may be included in the primer composition, OPV, and seaming solution described herein. Exemplary crosslinking agents include melamine formaldehyde, polyethyleneimine (aziridine), ammonium zinc carbonate, ammonium zirconium carbonate, sodium hydroxide, potassium hydroxide, and mixtures thereof. The inclusion of a crosslinking agent may further improve or enhance the resistance properties of the composition. The amount of crosslinking agent included in the composition may be about 0.05% to 15% by weight.

[0136] wax In one embodiment, waxes may be included in the primer compositions, OPV, and seaming solutions described herein. The waxes may be in powder form or aqueous dispersions thereof. Suitable waxes that may be used in the composition include, but are not limited to, polyethylene (PE), polypropylene (PP), ethylene acrylic acid (EAA), ethylene vinyl alcohol (EVA), paraffin, amide, carnauba wax, and mixtures thereof. The waxes may be included in the composition in an amount of 0.05% to 15% by weight.

[0137] Additives In one embodiment, additives may be included in the primer compositions, OPVs, and seaming solutions described herein. Additives include, for example, defoamers, wetting agents, leveling agents, colloid stabilizers, rheology modifiers, biocides, insecticides, surfactants, adhesion promoters, silicones, light stabilizers, degassing additives, waxes, ammonia, flow promoters, defoamers, antioxidants, stabilizers, dispersants, plasticizers, rheology additives, and the like, and combinations thereof. Additionally, other additives may be included in the composition to enhance the utility of the coating composition, or the coating produced by curing the coating composition. For example, plasticizers, antimicrobial agents, colorants, optical brighteners, ultraviolet light absorbers, antioxidants, and the like may be incorporated into the coating compositions of the present invention as needed. Additives may be included in the composition in an amount of 0.05% to 15% by weight.

[0138] Filler In one embodiment, additives may be included in the primer compositions, OPV, and seaming solutions described herein. Suitable fillers include, for example, talc, clay, alumina, silica, titanium dioxide, sodium hexametaphosphate, calcium carbonate, and mixtures thereof. Other materials may be used. Fillers may be included in the composition in an amount of 0.05% to 15% by weight.

[0139] Coloring agent In one embodiment, a colorant may be included in the primer composition, OPV, and seaming solution described herein. Suitable colorants include, but are not limited to, organic or inorganic pigments and dyes known to those skilled in the art. Suitable dyes include, for example, fluorescent dyes, azo dyes, anthraquinone dyes, xanthene dyes, azine dyes, and combinations thereof. The organic pigment may be one pigment or a combination of pigments such as, for example, Pigment Yellow Nos. 12, 13, 14, 17, 74, 83, 114, 126, 127, 174, 188, Pigment Red Nos. 2, 22, 23, 48:1, 48:2, 52, 52:1, 53, 57:1, 112, 122, 166, 170, 184, 202, 266, 269, Pigment Orange Nos. 5, 16, 34, 36, Pigment Blue Nos. 15, 15:3, 15:4, Pigment Violet Nos. 3, 23, 27, and / or Pigment Green No. 7.

[0140] Inorganic pigments that may be included in the composition are, for example, iron oxide, titanium dioxide, chromium oxide, ferric ammonium ferrocyanide, black ferric oxide, pigment black number 7, and / or pigment white numbers 6 and 7. Other organic and inorganic pigments and dyes, as well as combinations to achieve the desired color, may also be employed.

[0141] In one embodiment, the described compositions are clear, i.e., the compositions do not contain colorants.

[0142] In one embodiment, the coating is colored. For example, the OPV may contain TiO2 pigments that make the OPV white and opaque.

[0143] In one aspect, the coatings described herein can be energy curable. For example, the coatings can be cured by exposure to ultraviolet (UV) energy or energy emitted by an electron beam (EB) source.

[0144] One or more (or all) of the coatings described herein may be digitally printed, such as on an HP Indigo press. One or more or all of the coatings may be digitally printed in-line. Alternatively, the coatings of the present invention may be applied to the substrate offline by conventional coating techniques. For example, the coatings may be applied to the substrate by printing techniques such as flexographic ("flexo"), gravure, lithographic, offset, and screen printing, and may be applied by other methods such as roller coating, rod coating, roll metering, blade coating, comma coating, spray coating, screen coating, and rotary screen coating. Those skilled in the art may adjust parameters such as coating viscosity and coating solids content for each such application technique. The substrate may be paper, film, or nonwoven, and in one embodiment, the application is by printing using a flexographic or gravure press.

[0145] The coating weight depends on the deposition technique used and the end user application. Typically, the coating weight is less than 0.5 g / m 2 ~10g / m 2 , preferably 1 g / m 2 and 6 g / m 2 , and even more preferably 1.5 g / m 2 and 4 g / m 2 These coating weights are dry coating weights.

[0146] In one aspect, described herein is a shrink sleeve label substrate coated with the coating of the present invention. The shrink sleeve label substrate is a shrinkable polymeric film that can be shrunk to a smaller size, such as shrinking, when exposed to heat. The shrink sleeve label can be formed into an endless loop by forming a seam from the contact edges of the shrink sleeve label substrate. The seam is formed with a seaming solution according to one of the aspects described in this disclosure. The seam, i.e., the contact edges, can be formed from an overlap of edges joined together by a seaming solution disposed on one or both of the edges. The overlap can be 7 mm or less (e.g., 6 mm, 5 mm, 4 mm, etc.) from the edge of the substrate. The endless loop formed from the seamed shrink sleeve label substrate can be conformed over an article, such as plastic containers and bottles, and other goods. Once placed over the article, the endless loop is exposed to heat, such as heat provided in a heat tunnel. When exposed to heat, the shrink sleeve label shrinks and the endless loop can conform to the shape of the article, thereby providing a tight, snug fit of the shrunken loop to the shape of the article.

[0147] In one embodiment, the entire shrink sleeve label film substrate is coated with one or more coatings, i.e., the primer composition and the OPV. While the seaming solution may be so coated, typically the seaming solution is applied only within the seaming area, e.g., within 7 mm or one or more of the edges where the seam will be formed.

[0148] Seaming Solution Preferably, the seaming solution of the present invention comprises about 0% to 50% by weight of a polyester resin or polyester resin blend and 50% to 100% by weight of one or more solvents, where the polyester, if present, has a Tg of about -10°C to about 50°C, and one of the solvents is a seam welding solvent. In one embodiment, the seaming solution has a viscosity of 1.0 cP to 50 cP as measured at or near 25°C, 30 rpm with a Brookfield DV-2T viscometer equipped with spindle SC4-18(18). The Tg of the polyester blend is the Tg value of the combined polyester resins.

[0149] More preferably, the seaming solution of the present invention comprises about 0% to 25% by weight of a polyester resin or polyester resin blend and 80% to 100% by weight of one or more solvents, where the polyester, if present, has a Tg of about -10°C to about 50°C, and one of the solvents is a seam welding solvent. In one embodiment, the seaming solution has a viscosity of 1 cP to 50 cP as measured at or near 25°C, 30 rpm with a Brookfield DV-2T viscometer equipped with spindle SC4-18(18). The Tg of the polyester blend is the Tg value of the combined polyester resins.

[0150] Known seam welding solvents can be used in the seaming solution. Exemplary seaming solvents include tetrahydrofuran (THF), 1,3-dioxolane, dioxane, n-hexane, cyclohexane, methylcyclohexane, methyl ethyl ketone (MEK), acetone, methyl isobutyl ketone (MIBK), methyl acetate, methanol, isopropyl alcohol, and combinations thereof. THF, MEK, and 1,3-dioxolane are preferred.

[0151] Exemplary commercially available polyester resins that may be included in the seaming solution include Evonik's Dynapol® L206, L208, 490, and Toyobo's Vylon® 200, 390. Other polyester resins are listed in Table 3 below.

[0152] In one aspect, the seaming solution may also contain hydrogenated rosin, such as a hydrogenated rosin selected from partially hydrogenated rosin, fully hydrogenated rosin, and combinations thereof. In another aspect, the seaming solution does not include hydrogenated rosin.

[0153] The hydrogenated rosin can be, for example, a hydrogenated rosin selected from partially hydrogenated rosin, fully hydrogenated rosin, and combinations thereof, the hydrogenated rosin having one or both of a Tg or softening point lower than the first resin but higher than the second resin, and an acid number between 80 mg KOH / g and 200 mg KOH / g.

[0154] The hydrogenated rosin can be, for example, a hydrogenated rosin selected from partially hydrogenated rosin, fully hydrogenated rosin, and combinations thereof, the hydrogenated rosin having one or both of a lower Tg or softening point than the first and second resins, and an acid number between 80 mg KOH / g and 200 mg KOH / g.

[0155] Hydrogenated rosin materials may provide green bond strength to the composition, may soften in hot caustic baths, and may be hydrolyzable in hot caustic baths, but are not soluble. Such materials may be obtained from Eastman Chemical Company, Kingsport, Tennessee, under the trade name FORAL®, at least some of which are thermosetting. Foral AX-E, a fully hydrogenated rosin, may be included.

[0156] The seaming solution composition may optionally contain a colorant, such as a dye, pigment, taggant, or fluorophore, to visualize the deposit or to provide a means of notifying someone encountering the labeled article that the seaming solution is present on the label. EXAMPLES

[0157] The following examples illustrate certain aspects of the present invention and are not intended, and should not be construed, as limiting its scope in any way. These examples are illustrative and should not be read as limiting the scope of the invention, as the scope of the invention is defined by the appended claims. [Table 1]

[0158] The primer was prepared by mixing the above ingredients together in a Dispermat mixer until blended.

[0159] Example 1 was printed on PET-G film using a 2.07 BCM (1000 lines per inch) anilox roller on a Soloflex flexographic press at a speed of 75 m / min. The drying temperature was 50° C. to 60° C. The primer of Example 1 was applied to the entire surface of the film, i.e., without lane priming.

[0160] Table 2. Compositions and properties of OPVs of Examples 2 to 4 Comparative Example 4 does not contain gum rosin. [Table 2]

[0161] Example 2: In a 6 oz jar, 0.2g of Foamblas 1051, 7g of Reactol 5145A, and 8g of Hydro-Rez 3886 were added to 56.25g of water and 4g of ammonium hydroxide. The mixture was mixed until all solids were completely dissolved, and then 19.2g of Joncryl ECO-2177 was added to the mixture while mixing. After mixing for an additional 15 minutes, 1g of Aquacer 3RC1452, 0.2g of Hydrocer 357, 1g of Pen-cote DUHV, 1g of Geropon 99, 0.05g of Proxel GXL, 0.1g of Blancophor 150 LQ01, and 2g of Hydricure ZP were each added and then mixed for 30 minutes. The final product was left on the benchtop at room temperature for several hours before printing.

[0162] Example 3: In a 6 oz jar, 0.2g of Foamblast 1051, 10g of Reactol 5145A, and 10g of Hydro-Rez 3886 were added to 61.25g of water and 4g of ammonium hydroxide. The mixture was mixed until all solids were completely dissolved, and then 9.2g of Joncryl ECO-2177 was added to the mixture while mixing. After mixing for an additional 15 minutes, 1g of Aquacer 3RC1452, 0.2g of Hydrocer 357, 1g of Pen-cote DUHV, 1g of Geropon 99, 0.05g of Proxel GXL, 0.1g of Blancophor 150 LQ01, and 2g of Hydricure ZP were each added and then mixed for 30 minutes. The final product was left on the benchtop at room temperature for several hours before printing.

[0163] Comparative Example 4: In a 6 oz jar, 0.2g of Foamblast 1051 and 74.75g of Joncryl ECO-2177 were added to 19.7g of water. After mixing for 15 minutes, 1g of Aquacer 3RC1452, 0.2g of Hydrocer 357, 1g of Pen-cote DUHV, 1g of Geropon 99, 0.05g of Proxel GXL, 0.1g of Blancophor 150 LQ01, and 2g of Hydricure ZP were each added to the mixture and then mixed for 30 minutes. The final product was left on the benchtop at room temperature for several hours before printing.

[0164] The OPVs of Examples 2-4 were applied using a K-Lox4 BCM anilox roller to PET-G film printed with the primer and HP Indigo inks of Example 1. After application, the coatings were allowed to dry at 25° C. for 2 hours before testing.

[0165] As shown in Table 2, inventive Examples 2 and 3 contain 56.1% and 73.7% gum rosin ester by weight, respectively, based on solids weight, and Comparative Example 4 contains 0% gum rosin ester by weight, based on solids weight. Inventive Examples 2 and 3 showed better tape adhesion, better abrasion resistance, and a lower dry static friction coefficient than Comparative Example 4. The results indicate that gum rosin ester can form a stronger bond with the PET-G shrink sleeve and improve the mechanical properties of the OPV. [Table 3]

[0166] ADH100 is a commercially available seaming solution available from Sun Chemical Corporation, Parsippany, New Jersey.

[0167] The seaming solution was prepared by blending the ingredients together and mixing until all ingredients were dissolved and the solution was clear.

[0168] Examples 5-8 were used to form continuous adhesively bonded seams on overlapping longitudinal edges of PET-G shrink sleeves printed with either primer (Example 1) or OPV. [Table 4]

[0169] [Table 5]

[0170] As shown in Table 5, Example 5 and ADHA100 were used as seaming solutions to bond PET-G substrates printed with the primer of Example 1 (with primer coverage to the edge of the substrate (i.e., without lane priming)). In both cases, the T peel strength was greater than 20 gf and the S tensile strength was greater than 3,000 gf / inch, ensuring successful shrink application. Notably, the shrink sleeve labels made with the inventive primers Example 1 and ADHA100 could be removed within 10 minutes when immersed in a hot caustic bath at 75° C. containing 1 wt % NaOH. [Table 6]

[0171] In Table 6, Example 6 was used as a seaming solution to bond substrates printed with OPV Examples 2 and 3. Comparative Example 4 provided poor adhesive strength (2 hr S tensile strength less than 3,000 gf / in, and 24 hr T peel strength less than 20 gf) and the resulting samples failed in shrink applications.

[0172] Table 6 shows that the OPV described herein improves adhesive strength. The OPV described works in conjunction with the seaming solution described herein to ensure sufficient adhesive strength of the shrink sleeve label. [Table 7]

[0173] Table 7 shows the results of the seaming solutions of Comparative Examples 7 and 8 when used on inventive OPV Example 2. The T-peel adhesion strength of both samples was less than 20 gf and both failed the shrink application test.

[0174] Primer composition of the present invention compared to formulation 2 of U.S. Pat. No. 7,985,483 The primer composition of Example 1 was compared to a comparative primer composition (Comparative Example 9) according to Formulation 2 of U.S. Patent No. 7,985,483, which describes different amounts of ingredients. The formulations are shown in Table 8 below. [Table 8]

[0175] Alberdink® U-4000 VP is an aliphatic polyurethane dispersion.

[0176] DSM's Neorez® R-600 is an aliphatic polyurethane dispersion.

[0177] Cohesa X3060 is an ethylene acrylic acid (EAA) emulsion.

[0178] Michem PR4990 is a dispersion of ethylene acrylic acid copolymer.

[0179] The adhesion of the primer composition to the OPP was measured, and the adhesion of HP Electroink to the OPP substrates primed with Example 1 and Comparative Example 9 was measured and is reported in Table 9. [Table 9]

[0180] ADHA100 seaming solution was used to form a continuous adhesively bonded seam on the overlapping longitudinal edges of PET-G shrink sleeves printed with the primer composition of Example 1 and the primer composition of Comparative Example 9. The adhesive strength and shrink application results are shown in Table 10. The combination of Comparative Example 9 with ADHA100 resulted in a 2-hour T peel strength of less than 20 gf, resulting in a failure in the shrink application test. [Table 10]

[0181] The solubility of the components of Example 1 and Comparative Example 9, as well as the two examples themselves, was tested at 1% w / w in five different solvents, including THF, DMF, MEK, toluene, and N-propanol. The five solvents have different Hansen Solubility Parameters (HSP), covering almost the entire range of solubility defined by dispersion (van der Waals), polarity, and hydrogen bonding. As shown in Table 11, none of the materials are soluble in DMF, MEK, or toluene, and only NeoRez R-600 is soluble in N-propanol. However, both components of Comparative Example 9, as well as Comparative Example 9 itself, are soluble in THF. Meanwhile, none of the components of Inventive Example 1 are soluble in THF. Inventive Example 1 itself is similarly insoluble. [Table 11]

[0182] The printing method used in the examples of the present disclosure does not exclude that the composition can be applied to other substrates by other methods. Those skilled in the art will know how to adjust the formulation in terms of viscosity, rheology, etc. to make it suitable for application by other methods (e.g., flexography, gravure printing, blade coating, curtain coating, rod / bar coating).

[0183] Test Method: The solids content of the coating solution was determined based on the weight difference of the composition before and after evaporation of water and other volatile liquid materials. Evaporation was effected by heating 1 gram of the composition at 150° C. for 30 minutes.

[0184] Viscosity was measured at or near 25° C. with a Brookfield DV-2T viscometer equipped with spindle SC4-18(18) at 30 rpm.

[0185] Foam volume was determined by an aeration test in which 70 mL of coating composition was placed in a graduated cylinder and purged with air through a tube equipped with a fritted glass tip at 100 mL / min for 5 minutes. After purging was stopped, the foam volume was recorded. Less than 25% of the foam volume was above 70 mL was considered a pass.

[0186] Sutherland Rub Test (ASTM D5264). Printed samples were tested using a Sutherland Rub Tester. The test sample was attached to the base rubber pad of the rub tester. For dry rub testing, a dry felt pad was attached to the top (receptor) rubber pad of the rub tester. The rub tester was set to perform 100 strokes with a 4 pound weight. A stroke is one back and forth cycle. Results are reported as pass / fail. Less than 10% ink removal is considered a pass.

[0187] Dry CoF was tested coated side to coated side with a TMI Coefficient of Friction Tester. For dry CoF, a static CoF of 0.20-0.33 and a dynamic CoF of 0.18-0.28 are considered to pass. Wet CoF was tested similarly coated side to coated side with a TMI Coefficient of Friction Tester, except that approximately 0.5 mL of water was added prior to testing. For wet CoF, a static CoF of less than 1.68 and a dynamic CoF of less than 1.13 are considered to pass.

[0188] Adhesion was tested with 610 tape. Scotch 610 adhesive tape was applied to the printed and dried samples. The tape was manually removed with a slow pull followed by a fast pull in a direction perpendicular to the printed surface. The tape was removed immediately after application. If no coating was removed from the substrate it was considered a pass.

[0189] The substrates were seamed with seaming solution, with the coated side facing the uncoated side (front side of the substrate). The seaming solution was applied using a Q-tip in combination with a manual seaming machine from Ryback & Ryback (Monroe, NC, USA). The seam width was controlled to be 2-5 mm.

[0190] The T-peel adhesion strength of the seams was measured along the direction of seaming according to ASTM method D1876 using an Instron Model 3342 Single Column Universal Testing System with a load of 50 N and a crosshead speed of 300 mm / min. The average peel load at the mean value (integral) was determined from the autorecorded curve between the first and last peaks. The T-peel adhesion strength is the average peel load in grams force (or Newtons) required to separate the bonded sleeves.

[0191] The breaking strength of the seam in the shrink direction (perpendicular to the seaming), the S tensile strength, was measured in the same general manner as the "T-peel" adhesive strength. The breaking strength is the maximum peel load in grams per inch (or Newtons per inch) of seam width required to separate the bonded sleeves.

[0192] Shrink tests were performed by immersing empty bottles wrapped in seamed shrink sleeves in Ryback and Ryback S3 steam machines for 5-10 seconds depending on the technology. A passing grade is given if the sleeve shrinks snugly around the bottle and the seam remains intact emerging from the steam pot.

[0193] Deceasing was measured by immersing the sleeved bottle in a water bath containing a caustic solution at a temperature intended to simulate the conditions of a full bottle (pre)wash process used in typical wet-grind PET recycling. Unless otherwise specified, the bath conditions were 1.0 wt% NaOH at 75°C. Deceasing time was the measured time from immersion of the bottle in the caustic solution until the sleeve label was completely separated from the bottle.

[0194] Aspects of the present invention have been described in detail, including preferred embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of this disclosure, may make modifications and / or improvements thereto within the scope and spirit of the invention.

Claims

1. 1. A method of preparing a substrate for labeling an article, comprising the steps of: applying a primer composition to the substrate without lane priming; The primer composition comprises: 60% to 95% by weight, based on the total weight of the primer composition, of an aqueous polyurethane dispersion; 5.0% to 40% by weight, based on the total weight of the primer composition, of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers; Including, The method is carried out to enable printing of substrates that have presented difficulties when used in digital printing operations.

2. 10. The method of claim 1, wherein the primer composition is applied by a process selected from the group consisting of digital printing, inkjet, offset, flexographic, lithographic, gravure, screen printing, roll coating, spray coating, and die coating.

3. The method of claim 1 or 2, further comprising applying a liquid toner ink composition over the primer composition.

4. The method of claim 3 , wherein the primer composition promotes adhesion of the liquid toner ink composition to the substrate, wherein the substrate is a polymeric substrate.

5. The method of any one of claims 1 to 4, wherein the substrate is a heat shrinkable polymer substrate.

6. The method of claim 5 , wherein the heat shrinkable polymeric substrate is suitable for use in shrink sleeve labeling of an article.

7. The method of any one of claims 1 to 3, wherein the substrate is selected from the group consisting of untreated paper, art paper, coated paper, paperboard, polymeric film, and nonwoven fabric.

8. 8. The method of claim 7, wherein the substrate is a polymer film and the polymer is selected from the group consisting of polyethylene terephthalate, polyethylene terephthalate glycol, polybutylene terephthalate, polycarbonate, polyolefin, cyclic polyolefin, alpha-polyolefin, polyethylene, polypropylene, oriented polypropylene, polystyrene, oriented polystyrene, polyvinyl chloride, and nylon.

9. 1. A primer composition comprising: 60% to 95% by weight, based on the total weight of the primer composition, of an aqueous polyurethane dispersion; 5.0% to 40% by weight, based on the total weight of the primer composition, of an aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers; Including, A primer composition, characterized in that application of said primer composition to a substrate allows printing of substrates that have shown difficulties when used in digital printing operations, and does not interfere with the ability of a seaming solution to form a sufficiently strong bond to attach a label to the substrate.

10. 10. The primer composition of claim 9, wherein the polyurethane dispersion comprises a polyurethane that is the reaction product of (A) a polyisocyanate component, (B) a polyol component, and (C) an isocyanate-reactive component that includes ionic or potentially ionic groups.

11. 11. The primer composition of claim 10, wherein the polyisocyanate component of the polyurethane dispersion is selected from diisocyanates and diisocyanate reaction products containing urethane groups, urea groups, uretdione groups, uretonimine groups, isocyanurate groups, iminooxadiazinedione groups, oxadiazinetrione groups, carbodiimide groups, acylurea groups, biuret groups, allophanate groups, and combinations thereof.

12. The polyisocyanate component is selected from the group consisting of 4,4'-diisocyanatocyclohexylmethane, hexamethylene diisocyanate, 1-methyl-2,4(2,6)-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, norbornane diisocyanate, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, 4,4'-diisocyanatodiphenylmethane, xylylene diisocyanate, tetramethylene diisocyanate, 12. The primer composition of claim 10, wherein the diisocyanate is selected from the group consisting of 1,4-diisocyanatobutane, 1,12-diisocyanatododecane, 2,3,3-trimethylhexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexyl diisocyanate, α,α,α',α'-tetramethyl-m- or p-xylylene diisocyanate, triphenylmethane 4,4',4"-triisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate, and combinations thereof.

13. The primer composition of any one of claims 10 to 12, wherein the polyol component is selected from oligomeric or polymeric compounds having terminal hydroxyl groups, pendant hydroxyl groups, and combinations thereof.

14. The primer composition according to any one of claims 10 to 13, wherein the polyol component is selected from polyether polyols, polyester polyols, polyacrylic polyols, and polycarbonate polyols.

15. 15. The primer composition of claim 10, wherein the polyol component is selected from polyether polyols, polyester polyols, polyacrylic polyols, polycarbonate polyols including tetrahydrofuran, styrene oxide, propylene oxide, ethylene oxide, butylene oxide, epichlorohydrin, ethylene glycol, 1,2-propanediol, 1,3-propanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, bis-hydroxymethylcyclohexane, 2,2-bis-(4-hydroxyphenyl)propane, trimethylolpropane, glycerol, triethanolamine, pentaerythritol, tris-(2-hydroxyethyl)isocyanurate, and mixtures thereof.

16. 16. The primer composition of claim 10, wherein the isocyanate-reactive component is selected from 2,2-bis(hydroxymethyl)-alkanecarboxylic acids, dimethylolacetic acid, 2,2-dimethylol-propionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, hydroxypivalic acid, and combinations thereof.

17. The primer composition of any one of claims 9 to 16, wherein the polyurethane dispersion has a solids content of 5.0% to 55% by weight.

18. 18. The primer composition of any one of claims 9 to 17, wherein the α-olefin component of the copolymer of one or more α-olefins and one or more acid-based monomers is selected from ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof.

19. 19. The primer composition of any one of claims 9 to 18, wherein the acid-based monomer component of the aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers is selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, citraconic acid, citraconic anhydride, methyl hydrogen maleate, ethyl hydrogen maleate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutyl acrylate, methyl fumarate, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl chloride, vinylidene chloride, acrylamide, acrylonitrile, methacrylonitrile, fumaronitrile, derivatives thereof, and combinations thereof.

20. 20. The primer composition of any one of claims 9 to 19, wherein the aqueous dispersion of copolymers of one or more α-olefins and one or more acid-based monomers is derived from ethylene, acrylic acid, methacrylic acid, and combinations of acrylic acid and methacrylic acid.

21. The primer composition of any one of claims 9 to 20, wherein the aqueous dispersion of copolymers of one or more α-olefins and one or more acid-based monomers has a solids content of 10% to 60% by weight.

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