JP2017524751A - UV curable ink composition - Google Patents

Abstract

The present disclosure relates to ultraviolet curable ink compositions, methods of using and applying the compositions, and articles to which the compositions have been applied. In some embodiments, the UV curable ink composition can be printed using an inkjet printer. In some embodiments, the UV curable ink composition comprises (1) at least 12 wt% N-isopropylacrylamide, (2) 25 wt% or less hydroxy acrylate, and (3) N-vinylcaprolactam. An ultraviolet curable ink composition. At least some embodiments of these UV curable ink compositions minimize the incidence or adverse effect of plasticizer migration to the ink layer.

Description

  This application relates to ultraviolet curable ink compositions, methods of using and applying the compositions, and articles to which the compositions are applied. In one embodiment, the present application relates to an ultraviolet curable ink composition that can be printed using an inkjet printer.

  Advertising and promotional displays often include graphic images that are displayed on the surface of structures such as truck sides, awnings, and / or hanging banners. In some embodiments, the graphic image is formed on an image receiving medium (sometimes referred to as a graphic marking film) having an adhesive back surface, which is then adhered to the desired substrate. In another embodiment, the image is formed on a plasticized polymer (eg, vinyl) film, which can then be used as a banner, awning, and the like.

  A plasticizer is an additive that increases the plasticity or flowability of a material. Plasticizers have been used for many years to control the processability of polymers (eg, polyvinyl chloride) utilized in graphic films and banners. The plasticizer can be essentially monomeric or polymeric. The most common plasticizer used in PVC is a monomer plasticizer such as dioctyl phthalate. In addition to phthalate esters, other plasticizer materials include sebacate, adipate, terephthalate, dibenzoate, glutarates, and azelate. One of the disadvantages of including these (monomer) plasticizers is that the plasticizer can migrate to the surface over time and can cause the surface to feel sticky or tacky. Another disadvantage of including these plasticizers is that the plasticizer can migrate to a layer adjacent to the film (eg, an adhesive that bonds to the substrate). Plasticizer migration is often accelerated, for example, by high temperatures that occur during exposure to sunlight or UV curing. The plasticizer migration can also lead to a decrease in the plasticizer of the polymer layer, which greatly reduces the elasticity over time, thereby making the layer brittle and cracking the film. Thus, plasticizer migration can reverse or degrade key properties of the polymer layer, such as moisture tightness, flexibility, and aging stability.

  The inventors of the present application have noticed that the plasticizer in the plasticized polymer film also migrates into the ink that forms the graphic image. Such plasticizer migration has undesirable effects on the ink and ink / film combination, including, for example, reduced ink adhesion over time, film embrittlement, and / or ink An increase in the feeling of stickiness can be mentioned. Some or all of these undesirable properties increase when the substrate to which the ink is applied is repeatedly folded (eg, used as a waterproof fabric). Some or all of these undesirable properties increase when the ink is cured at high temperatures, which can undesirably increase plasticizer migration.

  The inventors of the present disclosure have found that at least some of these undesirable properties are minimized when certain novel ink compositions are applied to plasticizer-containing polymer films, or Found to be removed.

  Some embodiments of the present disclosure provide for an ultraviolet curable ink composition comprising (1) at least 12 wt% N-isopropylacrylamide, (2) 25 wt% or less hydroxy acrylate, and (3) N-vinylcaprolactam. Related to things. In some embodiments, the composition is applied to a substrate that is a polymer film comprising a plasticizer. In some embodiments, the polymer film comprises PVC.

  Some embodiments of the present disclosure are methods of applying a UV curable ink composition to a substrate comprising providing the substrate and (1) at least 12 wt% N-isopropylacrylamide, (2 Providing an ultraviolet curable ink composition comprising :) 25 wt% or less hydroxy acrylate, and (3) N-vinylcaprolactam; and applying the ultraviolet curable ink composition to the substrate. , Regarding the method. In some embodiments, the composition is applied to a substrate that is a polymer film comprising a plasticizer. In some embodiments, the polymer film comprises PVC.

  Some embodiments of the present disclosure are articles comprising a polymer substrate containing a plasticizer having a UV curable ink composition on the surface, the composition comprising at least 12% by weight of N-isopropylacrylamide. , 25 wt% or less of hydroxy acrylate, and N-vinylcaprolactam. In some embodiments, the polymer film comprises PVC.

  In some embodiments, the UV curable ink composition comprises at least 15% by weight N-isopropylacrylamide. In some embodiments, the UV curable ink composition comprises from about 12% to about 25% by weight N-isopropylacrylamide.

  In some embodiments, the UV curable ink composition comprises less than 20% by weight hydroxy acrylate. In some embodiments, the UV curable ink composition comprises less than 15% by weight of hydroxy acrylate. In some embodiments, the UV curable ink composition comprises from about 5% to about 25% by weight of hydroxy acrylate.

  In some embodiments, the UV curable ink composition comprises less than 20 wt% N-vinylcaprolactam. In some embodiments, the UV curable ink composition comprises less than 10% by weight N-vinylcaprolactam. In some embodiments, the UV curable ink composition comprises from about 5 wt% to about 15 wt% N-vinylcaprolactam.

  Applicants further note that an ink composition having a predicted Tg of about 46 ° C. or less has better crack resistance and is therefore cracked when applied to a folded substrate (eg, a waterproof fabric). I found it not. Since many substrates (eg, waterproof fabrics) are repeatedly folded during use, storage, processing, and / or application, such inks are preferably highly flexible. In some embodiments, the UV curable ink composition according to any of the preceding claims has a Tg of less than 46 ° C. according to the Fox equation. In some embodiments, the UV curable ink composition has a Tg of about 30 ° C. to about 46 ° C. according to the Fox formula.

  In some embodiments, the UV curable ink composition has a viscosity of 15 millipascal seconds or less at 60 ° C.

  Various embodiments and implementations are described in detail. These embodiments and implementations are not to be construed as limiting the scope of this application in any way, and changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the present application should be determined only by the claims.

  An ultraviolet curable ink composition of the type described herein comprises (1) at least 12 wt% N-isopropylacrylamide, (2) 25 wt% or less hydroxy acrylate, and (3) N-vinylcaprolactam, And an ultraviolet curable ink composition. The resulting composition exhibits an excellent combination with excellent flexibility and adhesiveness and no stickiness after a lapse of time. The resulting ink composition further exhibits excellent plasticizer resistance when placed directly adjacent to or on the polymer substrate containing the plasticizer. This ultraviolet curable ink composition is excellent in applications when the plasticizer-containing substrate to which the ink composition is adhered or applied is folded or bent during use, application, transportation, production, etc. ing. The resulting UV curable ink composition can be applied to a variety of substrates including, for example, those used in waterproof fabrics, barriers, banners, and / or packaging films.

  In some embodiments, preferred UV curable inks are applied to plasticized (in other words, plasticizer-containing) materials, particularly plasticized vinyl (eg PVC) materials. (1) presents minimal stickiness (initial and after time), (2) exhibits excellent ink adhesion, (3) passes folding test, and (4) Tg according to Fox equation It is 46 degrees C or less.

  In some embodiments, the UV curable ink composition is at least 12 wt%, at least 15 wt%, at least 17 wt%, at least 20 wt%, at least 22 wt%, at least 24 wt%, and about 25 wt%. % N-isopropylacrylamide. One advantage of using this particular acrylamide is that it has more desirable toxicity characteristics (eg, less toxicity) than other acrylamides (eg, dimethylacrylamide).

  In some embodiments, the UV curable ink composition comprises about 25 wt% or less, about 24 wt% or less, about 23 wt% or less, about 22 wt% or less, about 21 wt% or less, about 20 wt%. Or less, about 18% or less, about 16% or less, about 14% or less, about 12% or less, about 10% or less, or about 8% or less of hydroxy acrylate. Some representative hydroxy acrylates include 4-hydroxybutyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate.

  In some embodiments, the UV curable ink composition comprises from about 5 wt% to about 15 wt% N-vinylcaprolactam.

  In some embodiments, the UV curable ink composition is applied at a thickness of about 5-30 μm.

  If desired, sensitizers, coinitiators, and amine synergists can be included in the UV curable ink compositions of the present disclosure to increase cure speed. Examples include isopropylthioxanthone, ethyl 4- (dimethylamino) benzoate, 2-ethylhexyl dimethylaminobenzoate, and dimethylaminoethyl methacrylate.

  The UV curable ink composition of the present disclosure can optionally include one or more colorants. Useful colorants include dyes and pigments, which can be used alone or in any combination. Useful dyes and pigments can be of any color, for example, as described in US Pat. Nos. 6,294,592 (Herrmann et al.) And 6,114,406 (Caiger et al.) Both of these patents are well known in the art and are incorporated herein in their entirety. Preferably the colorant comprises at least one pigment. The amount of any colorant used in the UV curable ink composition of the present disclosure is typically less than 25 volume percent based on the total volume of the ink composition, but higher volume percentages are also used. be able to. Preferably, if a colorant is present, this is an amount ranging from 0.1 volume percent to 15 volume percent relative to the total volume of the ink composition.

  The ultraviolet curable ink composition of the present disclosure may optionally contain a solvent. The solvent may be composed of one or more non-reactive diluent materials, which may, for example, reduce the viscosity of the UV curable ink composition, reduce the surface tension of the UV curable ink composition, And / or may serve to dissolve constituents in the UV curable ink composition. Any amount of solvent can be utilized. In some embodiments of the present disclosure, for example, as described in PCT International Patent No. WO 02/38687 A1 (Ylitalo et al.) (Published May 16, 2002), which is incorporated herein in its entirety. A small amount of solvent can be added. In some embodiments of the present disclosure, the amount of any solvent incorporated is minimized and preferably is substantially zero (eg, less than 1 weight percent). Typical solvents include water, alcohols (eg, isopropyl alcohol (IPA) or ethanol), ketones (eg, methyl ethyl ketone, cyclohexanone, or acetone), aromatic hydrocarbons, isophorone, butyrolactone, N-methylpyrrolidone, tetrahydrofuran, Ethers (eg lactate, acetate, etc.), ester solvents (eg propylene glycol monomethyl ether acetate (PM acetate), diethylene glycol ethyl ether acetate (DE acetate), ethylene glycol butyl ether acetate (EB acetate), dipropylene glycol monomethyl acetate (DPM) Acetate), isoalkyl ester, isohexyl acetate, isoheptyl acetate, isooctyl acetate Over DOO, isononyl acetate, isodecyl acetate, isododecyl acetate, isotridecyl acetate or other iso-alkyl esters), as well as a combination thereof.

  In addition to the components described above, one or more other optional additives can be incorporated into the UV curable ink composition of the present disclosure. Typical additives include, for example, colorants, lubricity modifiers, thixotropic agents, foaming agents, antifoaming agents, fluidity or other rheology control agents, waxes, oils, plasticizers, binders, antioxidants. One or more of agents, stabilizers, conductive agents, fungicides, fungicides, organic and / or inorganic filler particles, leveling agents, opacifiers, antistatic agents, and / or dispersants.

  The ultraviolet curable ink compositions of the present disclosure can be cured, for example, by exposure to actinic radiation (ie, radiation having a wavelength in the ultraviolet or visible region spectrum). Suitable actinic radiation sources include mercury lamps, xenon lamps, carbon arc lamps, tungsten filament lamps, lasers, electron beam energy, microwave driven lamps, light emitting diodes, and the like. Preferably, the radiation source is a medium pressure mercury lamp or a light emitting diode.

  An image can be created using the inks described herein by one of several known methods such as screen printing, flexographic printing, lithographic printing, gravure printing, and inkjet printing. The ink can be applied as a coating using techniques such as knife coating and roll coating.

  Some advantages of the inks of the present disclosure are that they are not sticky after cure and are not sticky over time after cure (this is often a sign of undesirable plasticizer migration). . If the ink is excessively sticky, undesirable smearing will occur, leading to poor image quality and graphic appearance. Further, when the graphic film is wound on a roll, the ink may adhere to the graphic sheet portion directly adjacent to the ink. In other words, when the graphic film is wound, it may adhere to itself. When the roll is unwound, the ink on the single side printed graphic film is transferred to the unprinted back side of the graphic, which can destroy the image. In severe cases, this can cause sheet breakage in the affected area or potentially across the roll. The inks and articles and methods of the present disclosure prevent or minimize these undesirable events by removing or minimizing undesirable stickiness after curing.

  Furthermore, the inks, methods, and articles of the present disclosure exhibit excellent flexibility. The ink does not crack when the graphic film is rolled, folded, or folded. This facilitates attachment, storage and manufacture.

  The inks, methods, and articles of the present disclosure further exhibit excellent ink adhesion. Often a premask is applied to the graphic film to assist in the attachment process. Next, the pre-mask is peeled off from the graphic film to complete the attachment. It is essential that the ink on the graphic film remains in the desired and intended position during and after removal of the premask. The inks and methods and articles of the present disclosure exhibit excellent adhesion over the life of the graphic film.

  The advantages and embodiments of the present disclosure are further illustrated by the following examples, which unduly limit the present application by the specific materials and amounts listed therein and other conditions and details. It should be interpreted as not. In these examples, all percentages, ratios and ratios are by weight unless otherwise indicated.

Test Method Stickiness: Coated waterproof fabric samples were prepared as described in Comparative Examples A-N and Examples 1-14 below. The stickiness test (initial value) was carried out by placing the user's index finger on the sample. The user then assigned an attribute category to each sample. (A) means that the user did not feel stickiness, (B) felt a slight stickiness, and (C) meant that the user felt strong stickiness. The coated sample was then placed in a furnace heated to a temperature of about 65 ° C. for 3 days. The sample was then removed from the furnace and allowed to cool to room temperature. A sticky feeling test was performed on this heat-aged sample.

  Folding: A coated waterproof fabric sample, prepared as described in Comparative Examples A-N and Examples 1-14 below, was folded twice by applying light pressure along each crease line (mountain folding) And valley fold. Next, the folded sample was opened, and the user visually inspected the ink layer to check for crack lines. This test was conducted at a temperature of 20 ° C. If a crack was detected, the user classified the sample as “NG”. If no crack was detected, the sample was classified as “OK”.

  Ink adhesion test: A part of the ink layer of the coated waterproof cloth sample was scratched on the cross hatch pattern using a cutter knife. Adhesive tape (obtained from Nichiban Ltd. under the trade name SELLOTAPE) was applied to this cross hatch portion by applying pressure using a squeegee (obtained from model PA-1, 3M Company). The tape was then removed and the sample visually inspected to estimate the percentage (%) that the ink was removed from the waterproof fabric.

Predicted Tg of ink sample: The predicted glass transition temperature (Tg) of the sample was calculated using the following equation (Fox equation).
1 / Tg = W _A / Tg _A + W _B / Tg _B
Where
A and B: Monomer or oligomer Tg: Glass transition temperature of copolymer formed from A and B W _A and W _B : Weight fraction of _A and _B Tg _A and Tg _B : Tg value of homopolymer of A and B Prediction Tg is described in detail in PCT International Patent Publication No. US2013 / 033039, which is incorporated herein in its entirety.

(Example)
Comparative Examples A to N
Comparative Examples A-N were prepared by coating a PVC waterproof fabric (obtained from Miki Engineering as trade name SPC-0448) with the ink compositions listed in Tables 1 and 2 below. The ink composition is Meyer wire bar no. 7 and then cured with a 385 nm UV LED (303 mW / cm ² , 360 mJ / cm ² ) (Model LN-517VL385-FNEDTKHI, available from CCS Inc.).

  Comparative ink compositions A to N were prepared by mixing monomers, oligomers, and light stabilizers using a mixer at room temperature for 60 minutes at a speed of 2000 rpm. Next, a pigment (millbase containing cyan pigment, dispersant and IBOA) was added to the mixture and stirred for about 30 minutes.

  Comparative ink compositions (CI) A-N are listed in Tables 1 and 2 below. In these tables, the amount of each material is expressed in weight percent (% by weight) relative to the total weight of the composition.

(Examples 1-14)
Examples 1-14 followed the description in Comparative Examples A-N, but were prepared using the ink compositions listed in Tables 3 and 4 below. In these tables, the amount of each material is expressed in weight percent (% by weight) relative to the total weight of the composition.

  In Comparative Examples A to N and Examples 1 to 14, a qualitative stickiness test, a folding test, and an ink adhesion test using the above-described procedure were performed. In addition, the Tg of each composition was calculated using the Fox equation described above. The results are reported in Table 5.

  Samples coated with an ink composition comprising at least 12 wt% NIPAM, up to about 25 wt% hydroxy acrylate, and NVC samples did not show any increased stickiness after aging at 65 ° C for 3 days. The increase in stickiness can be attributed, for example, to the migration of the plasticizer from the substrate (eg, waterproof fabric) to the ink layer. Compositions with a predicted Tg of 46 ° C. or less have better crack resistance properties as observed in the folding test.

  All references mentioned herein are incorporated by reference in their entirety.

  Unless otherwise indicated, all numbers representing the size, quantity, and physical properties of features used in this disclosure and in the claims are understood to be modified in any case by the term “about”. It should be. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and the appended claims are the same as those desired by those skilled in the art using the teachings disclosed herein. It is an approximate value that can vary depending on the characteristics to be achieved. All numerical ranges include the endpoints and non-integer values between the endpoints unless otherwise specified.

  As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” have plural referents unless the content clearly dictates otherwise. Embodiments are included.

  As used in this disclosure and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

  The expressions “at least one of” and “including at least one of”, followed by the enumeration, refer to any one of the items in the enumeration and two or more in the enumeration Refers to any combination of items.

  Various embodiments and implementations of the present disclosure are disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation. These and other implementations are within the scope of the following claims. Those skilled in the art will appreciate that the present disclosure may be practiced with embodiments and implementations other than those disclosed. It will be appreciated by those skilled in the art that many changes can be made to the details of the above embodiments and examples without departing from the principles underlying the invention. This disclosure is not unduly limited by the specific examples and examples described herein, and such examples and embodiments are limited only by the claims set forth herein. It should be understood that this is intended to be exemplary only within the scope of this disclosure. In addition, various modifications and variations to the present disclosure will be apparent to those skilled in the art without departing from the spirit and scope of the disclosure. Accordingly, the scope of the present application should be defined only by the following “claims”.

Claims (53)

At least 12% by weight of N-isopropylacrylamide;
Up to about 25% by weight of hydroxy acrylate,
An ultraviolet curable ink composition comprising N-vinylcaprolactam.   The ultraviolet curable ink composition of claim 1, comprising at least 15 wt% N-isopropylacrylamide.   The ultraviolet curable ink composition of claim 1, comprising about 12 wt% to about 25 wt% N-isopropylacrylamide.   The ultraviolet curable ink composition according to any one of claims 1 to 3, comprising less than 20% by weight of hydroxyacrylate.   The ultraviolet curable ink composition according to claim 1, comprising less than 15% by weight of hydroxyacrylate.   6. The ultraviolet curable ink composition according to any one of claims 1 to 5, comprising from about 5% to about 25% by weight of hydroxy acrylate.   The ultraviolet curable ink composition according to claim 1, comprising less than 20% by weight of N-vinylcaprolactam.   The ultraviolet curable ink composition according to any one of claims 1 to 7, comprising less than 10% by weight of N-vinylcaprolactam.   The ultraviolet curable ink composition of any one of claims 1 to 8, comprising from about 5 wt% to about 15 wt% N-vinylcaprolactam.   The ultraviolet curable ink composition according to claim 1, wherein Tg according to the Fox formula is 46 ° C. or less.   11. The ultraviolet curable ink composition according to any one of the preceding claims, wherein the composition has a Tg according to the Fox formula of about 30C to about 46C.   The hydroxy acrylate comprises at least one of 4-hydroxybutyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate. The ultraviolet curable ink composition as described in any one of 1-11.   The composition has (1) a Tg according to the Fox equation of about 30 ° C. to about 46, (2) has an ink removal rate of less than 2% using the ink adhesion test, (3) The ultraviolet ray according to any one of claims 1 to 12, wherein there is no initial sticky feeling felt by the user using the sticky feeling test, and (4) no sticky feeling felt by the user after 3 days at 65 ° C. Curable ink composition.   The ultraviolet curable ink composition according to claim 1, wherein the ultraviolet curable ink composition has a viscosity of 15 millipascal seconds or less at 60 ° C. 15.   The ultraviolet curable ink composition according to claim 1, further comprising at least one colorant and / or solvent.   The ultraviolet curable ink composition according to claim 1, wherein the ink composition is LED curable.   The ultraviolet curable ink composition according to any one of claims 1 to 16, further comprising a plasticizer-containing substrate directly adjacent to the ultraviolet curable ink composition.   The ultraviolet curable ink composition according to claim 17, wherein the substrate comprises PVC. A method for applying an ultraviolet curable ink composition to a substrate comprising:
Preparing a substrate;
At least 12% by weight of N-isopropylacrylamide,
Up to about 25% by weight of hydroxy acrylate,
And N-vinylcaprolactam,
Preparing an ultraviolet curable ink composition comprising:
Applying the ultraviolet curable ink composition to the substrate;
Including the method.   The method of claim 19, wherein the substrate comprises PVC.   The method of claim 19, wherein the substrate contains a plasticizer.   20. The method of claim 19, further comprising exposing the UV curable ink composition to actinic radiation.   23. A method according to any one of claims 19 to 22 comprising at least 15 wt% N-isopropylacrylamide.   23. A method according to any one of claims 19 to 22 comprising from about 12% to about 25% by weight N-isopropylacrylamide.   25. A method according to any one of claims 19 to 24 comprising less than 20% by weight of hydroxy acrylate.   26. A method according to any one of claims 19 to 25 comprising less than 15% by weight of hydroxy acrylate.   27. A method according to any one of claims 19 to 26 comprising from about 5% to about 25% by weight of hydroxy acrylate.   28. A process according to any one of claims 19 to 27, comprising less than 20% by weight N-vinylcaprolactam.   29. A process according to any one of claims 19 to 28, comprising less than 10% by weight of N-vinylcaprolactam.   30. The method of any one of claims 19-29, comprising from about 5 wt% to about 15 wt% N-vinylcaprolactam.   The method according to any one of claims 19 to 30, wherein Tg according to the Fox formula is 46 ° C or lower.   32. The method of any one of claims 19-31, wherein the UV curable ink composition has a Tg according to the Fox formula of about 30C to about 46C.   20. The hydroxy acrylate comprises at least one of 4-hydroxybutyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate. 33. A method according to any one of -32.   The ultraviolet curable ink composition (1) has a Tg according to the Fox equation of about 30 ° C. to about 46 ° C., and (2) has an ink removal rate of less than 2% using the ink adhesion test. And (3) using the stickiness test, the user does not feel the initial stickiness, and (4) the user does not feel the stickiness after three days at 65 ° C. The method according to item.   The method according to any one of claims 19 to 34, wherein the viscosity of the ultraviolet curable ink composition is 15 millipascal seconds or less at 60 ° C. An article comprising a polymer substrate containing a plasticizer and having a UV curable ink composition on the surface, wherein the UV curable ink composition comprises:
At least 12% by weight of N-isopropylacrylamide,
Up to about 25% by weight of hydroxy acrylate,
And an article comprising N-vinylcaprolactam.   37. The article of claim 36, wherein the ultraviolet curable ink composition comprises at least 15% by weight N-isopropylacrylamide.   37. The article of claim 36, wherein the UV curable ink composition comprises from about 12% to about 25% by weight N-isopropylacrylamide.   39. An article according to any one of claims 36 to 38, wherein the UV curable ink composition comprises less than 20% by weight of hydroxy acrylate.   40. The article of any one of claims 36 to 39, wherein the ultraviolet curable ink composition comprises less than 15 wt% hydroxy acrylate.   41. The article of any one of claims 36-40, wherein the ultraviolet curable ink composition comprises from about 5 wt% to about 25 wt% hydroxyacrylate.   42. The article of any one of claims 36 to 41, wherein the ultraviolet curable ink composition comprises less than 20 wt% N-vinylcaprolactam.   43. The article of any one of claims 36 to 42, wherein the ultraviolet curable ink composition comprises less than 10 wt% N-vinylcaprolactam.   44. The article of any one of claims 36-43, wherein the ultraviolet curable ink composition comprises from about 5 wt% to about 15 wt% N-vinylcaprolactam.   45. The article according to any one of claims 36 to 44, wherein the UV curable ink composition has a Tg according to Fox formula of less than 46C.   46. The article of any one of claims 36 to 45, wherein the UV curable ink composition has a Tg according to the Fox formula of about 30C to about 46C.   37. The hydroxy acrylate comprises at least one of 4-hydroxybutyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate. The article according to any one of -46.   The ultraviolet curable ink composition (1) has a Tg according to the Fox equation of about 30 ° C. to about 46 ° C., and (2) has an ink removal rate of less than 2% using the ink adhesion test. And (3) using the stickiness test, the user does not feel the initial stickiness, and (4) the user does not feel the stickiness after three days at 65 ° C. Article according to item.   49. The article according to any one of claims 36 to 48, wherein the ultraviolet curable ink composition has a viscosity of 15 millipascal seconds or less at 60C.   50. The article according to any one of claims 36 to 49, further comprising at least one colorant and / or solvent.   51. The article according to any one of claims 36-50, wherein the ultraviolet curable ink composition is LED curable.   52. The article according to any one of claims 36 to 51, further comprising a plasticizer-containing substrate directly adjacent to the UV curable ink composition.   53. The article of any one of claims 36 to 52, wherein the substrate comprises PVC.