Plastic substrates and methods for removing marks or images therefrom

Abstract

The present invention relates to a method for removing marks or images from plastic substrates, as well as to plastic substrates and compositions applied to said substrates suitable for use in such methods.

Description

[Technical Field]

[0001] The present invention is directed to a method for removing marks or images from plastic substrates, as well as to plastic substrates and compositions applied directly to the substrates suitable for use in said method. [Background technology]

[0002] In recent years, efforts to recycle plastic substrates have increased significantly. However, the problems associated with recycling plastic substrates having compositions containing coloring compounds that display marks or images applied thereto are extensive. In particular, separating the coloring compounds and other components of the compositions used to display the marks or images from the plastic substrate after normal use, before, or during the recycling process can be difficult, resulting in contaminated and / or stained plastic material that cannot be properly recycled. The coloring compounds and other components of the compositions used to display the marks or images also contaminate waste streams during processing. Both issues result in additional costs and environmental problems.

[0003] It is therefore desirable to provide a plastic substrate that can effectively display a mark or image, but that can be recycled without contamination from the materials used to form the mark or image. Summary of the Invention

[0004] According to a first aspect of the present invention there is provided the use of a first composition comprising a protein for removing a mark or image from a plastic substrate, preferably through exposing the plastic substrate to an alkaline aqueous solution.

[0005] According to a second aspect of the present invention, there is provided use of a first composition for producing a plastic substrate having applied to at least a portion thereof or having incorporated therein a first composition and a second composition applied thereon, the first composition comprising a protein; the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye; the second composition displays a mark or image formed by irradiating a localized portion of the second composition with a laser, so that the plastic substrate displays the mark or image; and if the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator; and preferably, the mark or image can be removed from the plastic substrate by exposing the plastic substrate to an alkaline aqueous solution, thereby providing a plastic material that is not contaminated by the second composition.

[0006] According to a third aspect of the present invention, there is provided a plastic substrate applied to or incorporating at least a portion thereof, wherein a first composition comprises a protein, and a second composition is applied over the first composition, the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and wherein a mark or image can be formed when a localized location of the second composition is irradiated with a laser, and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator.

[0007] According to a fourth aspect of the present invention, there is provided a use of a first composition and a second composition in removing a mark or image from a plastic substrate having applied to or incorporated into at least a portion thereof a first composition comprising a protein to provide a plastic material that is not contaminated by the second composition, and a second composition applied over the first composition, wherein the second composition comprises a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and the second composition displays a mark or image formed by irradiating a localized portion of the second composition with a laser, so that the plastic substrate displays the mark or image, and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator, and the mark or image is preferably removed from the plastic substrate by exposing the plastic substrate to an alkaline aqueous solution.

[0008] According to a fifth aspect of the present invention, there is provided a method for removing a mark or image from a plastic substrate and providing a plastic material that is not contaminated with a second composition, the method comprising: applying a first composition containing a protein and a second composition applied over the first composition to at least a portion of the plastic substrate, or incorporating the first composition into at least a portion of the plastic substrate; the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye; the second composition displaying a mark or image formed by irradiating a localized portion of the second composition with a laser, such that the plastic substrate displays the mark or image; and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator; and the method comprises exposing the plastic substrate to an alkaline aqueous solution.

[0009] According to a sixth aspect of the present invention, there is provided a composition comprising a leuco dye, a thermal acid generator selected from amine salts of organometallic compounds, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12.

[0010] According to a seventh aspect of the present invention, there is provided a method for removing a mark or image from a plastic substrate and providing a plastic material that is not contaminated by the composition, the method comprising: use of a composition comprising a leuco dye, a thermal acid generator selected from an amine salt of an organometallic compound, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12; wherein a first composition comprising a protein and this composition applied over the first composition are applied to or incorporated into at least a portion of the plastic substrate; the leuco dye of the composition displays a mark or image; the mark or image is formed by irradiating a localized portion of the composition using a laser, so that the plastic substrate displays the mark or image; and the mark or image can be removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution, thereby providing a plastic material that is not contaminated by the composition.

[0011] According to an eighth aspect of the present invention, there is provided use of a composition comprising a leuco dye, a thermal acid generator selected from an amine salt of an organometallic compound, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12 for producing a plastic substrate, wherein a first composition comprising a protein and the present composition applied thereon are applied to or incorporated into at least a portion of the substrate, and the leuco dye displays a mark or image, and the mark or image is formed by irradiating a localized portion of the composition using a laser, so that the plastic substrate displays the mark or image, and the mark or image can be removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution, thereby providing a plastic material that is not contaminated by the composition.

[0012] According to a ninth aspect of the present invention, there is provided a plastic substrate having a composition applied to or incorporated into at least a portion thereof, the composition comprising a leuco dye, a thermal acid generator selected from an amine salt of an organometallic compound, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12.

[0013] According to a tenth aspect of the present invention, there is provided a method for forming or displaying a mark or image on a plastic substrate, the substrate having applied to or incorporated into at least a portion thereof a first composition comprising a protein and a second composition applied over the first composition, the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator, the method comprising irradiating a localized portion of the second composition using a laser.

[0014] According to an eleventh aspect of the present invention, there is provided a method for forming or displaying a mark or image on a plastic substrate, the method comprising applying to or incorporating into at least a portion thereof a composition comprising a leuco dye, a thermal acid generator selected from an amine salt of an organometallic compound, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12, the composition comprising: a leuco dye; an amine salt of an organometallic compound; an organic solvent; and an alkaline stabilizer having a pKa of 2 to 12; the method comprising irradiating a localized portion of the composition with a laser.

[0015] According to a twelfth aspect of the present invention, there is provided a method for forming a plastic substrate having applied to or incorporated into at least a portion thereof a first composition comprising a protein and a second composition applied over the first composition, wherein the second composition comprises a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and wherein a mark or image can be formed when a localized location of the second composition is irradiated with a laser, and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator, the method comprising applying the first composition and the second composition onto the plastic substrate or a component of the plastic material thereof, preferably by printing the first composition and the second composition onto the plastic substrate, more preferably by pad printing, screen printing, flexographic printing or gravure printing.

[0016] According to a thirteenth aspect of the present invention there is provided a method of forming a plastic substrate comprising a composition applied to or incorporated into at least a part of the plastic substrate, the composition comprising a leuco dye, a thermal acid generator selected from an amine salt of an organometallic compound, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12, and the method comprising applying the composition onto the plastic substrate or a component of the plastic material thereof, preferably by printing the composition onto the plastic substrate or a component of the plastic material thereof, more preferably by pad printing, screen printing, flexographic printing or gravure printing. DETAILED DESCRIPTION OF THE INVENTION

[0017] The inventors have surprisingly and advantageously identified plastic substrates capable of displaying a mark or image and from which the mark or image can be removed, allowing for the recycling of the plastic substrate uncontaminated from any of the materials used to form the mark or image. The inventors have identified compositions for direct application to a plastic substrate which effectively enable the plastic substrate to display a recognizable and identifiable mark or image under normal use conditions, but which can then be removed from the substrate to provide uncontaminated plastic material and an equally uncontaminated waste stream.

[0018] Using this invention, the inventors have discovered a method in which a laser-reactive composition can be applied to or incorporated into a plastic substrate, and then irradiation from a laser source(s) is used to cause the composition to display a mark or image, forming a plastic substrate displaying a recognizable and identifiable mark or image. These marks or images can then be removed from the plastic substrate through removal of the composition, providing uncontaminated plastic material and a waste stream, allowing for effective recycling of the plastic material. This methodology is suitable for all plastic substrates, including multilayer plastic structures ("laminate structures"), particularly those with layers formed from different plastic materials that must be separated and each undergo a different recycling process. The invention not only enables these multilayer plastic structures to display a recognizable and identifiable mark or image, but also advantageously allows for the mark or image to be subsequently removed, allowing for effective recycling of the different plastic materials that form the multilayer plastic structure. Currently, there are no established procedures for recycling multilayer plastic structures that overcome these challenges.

[0019] Thus, the present invention not only allows for the effective display of a mark or image, but also allows for the production of plastic substrates that allow for the removal of the mark or image from the plastic substrate, providing a plastic material and waste stream that is not contaminated by any of the materials used to form the mark or image, and allowing for the recycling of the plastic material.

[0020] As used herein in reference to a plastic substrate or plastic material, "uncontaminated" or "not contaminated" and similar terms mean that the plastic substrate or plastic material does not contain the second composition or composition comprising the coloring compound and is therefore free of a mark or image. This is the result of the second composition or composition comprising the coloring compound being separated from the plastic substrate or plastic material. The second composition or composition comprising the coloring compound is not retained on the plastic substrate or plastic material. This separation of the second composition or composition comprising the coloring compound occurs through the use of the first composition described herein, preferably by exposing the plastic substrate to an alkaline aqueous solution as described herein. As used herein in reference to a mark or image, "removed," "removing," or "removal" and similar terms mean that the plastic substrate or plastic material no longer displays said mark or image. The mark or image is separated from the plastic substrate or plastic material. This is the result of the second composition or composition comprising the coloring compound being separated from the plastic substrate or plastic material. The plastic substrate or plastic material is not contaminated by the second composition or the composition containing the coloring compound and therefore does not display a mark or image, and the mark or image is no longer visually detectable on the plastic substrate or plastic material by the human eye.

[0021] Removal of a mark or image can be examined by measuring the ΔE between an uncoated (and therefore image-free) plastic substrate or plastic material (control) and the plastic substrate or plastic material after exposure to an alkaline aqueous solution in the process of the present invention. For example, according to the present invention, a composition containing a first composition and a second composition or coloring compound is applied to a plastic substrate or plastic material, forming a mark or image. The mark or image is then removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution as described herein, according to the process described herein. Suitable ΔE measurements can be less than 5, less than 3.5, less than 3, or less than 2. Such ΔE measurements provide a good indication that there is no visually discernible difference between the control and the plastic substrate or plastic material resulting from exposure to an alkaline aqueous solution in the process of the present invention. This demonstrates that the plastic substrate or plastic material resulting from exposure to an alkaline aqueous solution in the process of the present invention does not display a mark or image, i.e., the mark or image has been removed. The composition containing the second composition or coloring compound is separated from the plastic substrate or plastic material. ΔE can be measured with an X-rite eXact spectrophotometer using standard mathematical calculations detailed herein. ΔE measurements can be performed on a white background.

[0022] For use according to the first aspect of the invention, removal of the mark or image provides a plastic substrate which no longer displays said mark or image.

[0023] In relation to the use according to the first aspect of the invention, the plastic substrate may be as defined herein in relation to the third aspect of the invention, wherein the plastic substrate displays a mark or image, said mark or image being formed by irradiating a localized portion of the second composition using a laser.

[0024] The alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention may be an aqueous solution of 0.1 to 5 wt.%, such as 0.5 to 3 wt.%, preferably 1 to 3 wt.%, etc. of a base, preferably an alkali or alkaline earth hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide, preferably sodium hydroxide.

[0025] The alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh, and eighth aspects of the present invention may further comprise a surfactant, such as a nonionic surfactant. The surfactant may provide cleaning properties. The surfactant may be present in the alkaline aqueous solution in an amount of 0.1 to 4 wt.%, preferably 0.1 to 1 wt.%, such as 0.1 to 0.6 wt.%.

[0026] The alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention may have a pH of 7-15, such as 9-14, or 12-14.

[0027] The exposure to the alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention may be carried out at a temperature of 50-95°C, such as 60-95°C, or 80-95°C, such as 80-90°C. The alkaline aqueous solution is at a temperature of 50-95°C, such as 60-95°C, or 80-95°C, such as 80-90°C.

[0028] Preferably, the exposure to aqueous alkaline solution utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention is carried out in aqueous sodium hydroxide solution, more preferably 0.1-5 wt.%, preferably 0.5-3 wt.%, more preferably 1-3 wt.% aqueous sodium hydroxide solution, preferably at a temperature of 50-95°C, such as 60-95°C, or 80-95°C, 80-90°C, etc.

[0029] The exposure to aqueous alkaline solutions utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention may be known as a "hot caustic wash" or washing in a "hot caustic solution."

[0030] It will be appreciated that the exposure to aqueous alkaline solution utilized in the first, second, fourth, fifth, seventh and eighth aspects of the present invention may be a soak or wash in an aqueous alkaline solution.

[0031] During exposure to the alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh, and eighth aspects of the present invention, at least partial solubilization of the first composition separates the second composition or the leuco dye-containing composition from the plastic substrate, thus removing the mark or image from the substrate. The first composition is at least partially solubilized in the alkaline aqueous solution and separates from the plastic substrate (and the second composition or the leuco dye-containing composition). The first composition is washed away in the wash stream. Thus, it is understood that the first composition, as well as the second composition or the leuco dye-containing composition, separates from the plastic substrate. The second composition or the leuco dye-containing composition remains as a solid or precipitate after exposure to the alkaline aqueous solution. The second composition or the leuco dye-containing composition is therefore separated from the plastic substrate. The second composition or the leuco dye-containing composition typically floats to the surface of the alkaline aqueous solution. The second composition or the leuco dye-containing composition can be removed by filtration.

[0032] It is understood that the plastic substrate is exposed to the alkaline aqueous solution utilized in the first, second, fourth, fifth, seventh, and eighth aspects of the present invention for a period of time sufficient to at least partially solubilize the first composition in the alkaline aqueous solution, thereby allowing the second composition or the composition comprising the leuco dye to be separated from the plastic substrate. The exposure to the alkaline aqueous solution can be for a period of 1 to 45 minutes, such as 1 to 30 minutes, or 1 to 20 minutes, such as 1 to 15 minutes, and preferably 1 to 5 minutes.

[0033] It is understood that the plastic substrate can be exposed to the aqueous alkaline solution utilized in the first, second, fourth, fifth, seventh, and eighth aspects of the present invention to separate the second composition or the leuco dye-containing composition prior to breaking down the plastic substrate into granules or flakes as part of the recycling process. Alternatively, and preferably, the plastic substrate can first be broken down into its granules or flakes, for example by crushing, grinding, or other suitable methods known in the art, and the plastic substrate granules or flakes can then be exposed to the aqueous alkaline solution to separate the second composition or the leuco dye-containing composition from the substrate. Thus, in the context of exposure to the aqueous alkaline solution utilized in the first, second, fourth, fifth, seventh, and eighth aspects of the present invention, reference to the plastic substrate can refer to either the plastic substrate as a whole (or at least a portion of the substrate to which the first composition and / or the second composition or the leuco dye-containing composition has been applied) or to the plastic substrate granules or flakes. Similarly, as described herein, the plastic material resulting from exposure to an alkaline aqueous solution may be the entire plastic substrate from which the mark or image has been removed, or may be granules or flakes of the plastic substrate from which the mark or image has been removed.

[0034] It is understood that when the plastic substrate is a multi-layer plastic structure in which different plastic materials are utilized in different layers, the different plastic materials are typically separated prior to recycling. Different plastic materials typically require different recycling processes. This separation is preferably achieved using an aqueous alkaline solution as described herein. Separation can be facilitated, for example, by utilizing the different physical properties of the materials, such as density differences between materials such as polyolefin and polyester materials.

[0035] Various industry standards can be used to demonstrate that uncontaminated plastic materials have been produced, such as the EPBP (European PET Bottle Platform) Quick Test QT 507 (March 2017) or the Natural HDPE Flake Washing Test (HDPE-S-01), Plastics Recycling Association, August 23, 2021. Different tests can be used depending on the type of plastic used in the plastic material, the structure of the plastic substrate, e.g., multi-layer plastic structures (laminate structures), as well as standards or requirements for recycling processes in different regions, as is well known to those skilled in the art.

[0036] A suitable test to demonstrate that uncontaminated plastic material has been produced can be summarized as consisting of the following steps. It is understood that the steps or conditions may vary depending, for example, on the type of plastic utilized in the plastic material, the structure of the plastic substrate, e.g., multi-layer plastic structures (laminate structures), as well as standards or requirements for recycling processes in different regions: 1. 1 cm of plastic substrate having the desired composition(s) applied or incorporated therein and displaying a mark or image 2 Obtain thin sections. 2. Place the slices in a 2 wt. % aqueous solution of sodium hydroxide at 500 rpm for 15 minutes at 80° C. Save the supernatant. 3. Repeat two more times. Rinse slices to remove water. 4. The flakes are dried in an oven at 105°C. 5. Color measurements of the slice and, optionally, the supernatant (L * , a * and b * The ΔE value is evaluated in comparison to a sample strip (control) that is not coated with the composition(s). A ΔE measurement between the control and the strip is obtained.

[0037] A suitable test to demonstrate that uncontaminated plastic materials have been produced may be the EPBP (European PET Bottle Platform) Quick Test QT 507 (March 2017) if the plastic substrate is formed from PET. The EPBP test may be summarized as consisting of the following steps: 1. 1 cm of plastic substrate (PET) having the desired composition(s) applied or incorporated therein and displaying a mark or image 2 Obtain thin sections. 2. Place the slices in a 2 wt. % aqueous solution of sodium hydroxide at 500 rpm for 15 minutes at 80° C. Save the supernatant. 3. Repeat two more times. Rinse slices to remove water. 4. The flakes are dried in an oven at 105°C. 5. Color measurements of PET slices and optionally the supernatant (L * , a * and b * The ΔE value is evaluated in comparison to a PET sample strip (control) that is not coated with the composition(s). A ΔE measurement between the control and the strip is obtained.

[0038] A suitable test to demonstrate that uncontaminated plastic materials have been produced may be the Natural HDPE Flake Washing Test (HDPE-S-01), Plastics Recycling Association, August 23, 2021, if the plastic substrate is formed from HDPE. This HDPE-S-01 test may be summarized as consisting of the following steps: 1. 1 cm of plastic substrate (HDPE) having the desired composition(s) applied or incorporated therein and displaying a mark or image 2 Obtain thin sections. 2. Place the slices in a 2 wt. % aqueous solution of sodium hydroxide at 500 rpm for 15 minutes at 80° C. Save the supernatant. 3. Repeat two more times. Rinse slices to remove water. 4. The flakes are dried in an oven at 105°C. 5. Color measurements of the HDPE slice and, optionally, the supernatant liquid (L * , a * and b * The ΔE value is evaluated in comparison to an HDPE sample strip (control) that is not coated with the composition(s). A ΔE measurement between the control and the strip is obtained.

[0039] It will be appreciated that if the plastic substrate is a multi-layer plastic structure, where two different plastic materials may be utilized, these plastic materials will typically be separated prior to drying and evaluation of color measurements (steps 4 and 5 above). This may be, for example, by utilizing different physical properties of the materials, such as density differences between materials such as polyolefin and polyester materials.

[0040] For all tests, whether general or specific, as detailed above, a ΔE measurement value can be used to examine the visual difference between a control (not coated with the composition(s) and therefore having no mark or image formed thereon) and a plastic substrate or plastic material (from which the mark or image has been removed) after exposure to the aqueous alkaline solution in the process of the present invention. ΔE can be measured with an X-rite eXact spectrophotometer using standard mathematical calculations as detailed herein. ΔE measurements can be performed on a white background. ΔE allows for the quantification of the visual perception of the difference between two colors. ΔE measurements can be less than 5, less than 3.5, such as less than 3, or less than 2. Such a ΔE measurement value provides a good indication that there is no visual perception of the difference between the control and the plastic substrate or plastic material resulting from exposure to the aqueous alkaline solution in the process of the present invention.

[0041] The first composition advantageously enables the second composition utilized in any of the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or the leuco dye-containing composition utilized in any of the sixth, seventh, eighth, ninth, eleventh and thirteenth aspects of the invention, to be separated from the plastic substrate, such that any mark or image displayed by the second composition or the leuco dye-containing composition is removed from the plastic substrate.

[0042] With regard to the second to fifth, tenth and twelfth aspects of the present invention, the colored compound may be selected from oxyanions or oxyacids of polyvalent metals or hydrates thereof, or leuco dyes.

[0043] When the coloring compound is a polyvalent metal oxyanion or a hydrate of a polyvalent metal oxyanion, it is preferably an ammonium salt of a polyvalent metal oxyanion, more preferably an ammonium salt of a molybdenum oxyanion. Most preferably, the polyvalent metal oxyanion or oxyacid or hydrate thereof is ammonium octamolybdate (AOM).

[0044] With respect to the second to fifth, tenth, and twelfth aspects of the present invention, the coloring compound is preferably a leuco dye. The leuco dye can facilitate the display of a colored mark or image, particularly a colored mark or image displaying a color other than black. Thus, the use of a leuco dye as the coloring compound advantageously enables the formation of a mark or image other than black on a plastic substrate, which can then be effectively removed from the plastic substrate bearing the mark or image formed by the laser-reactive composition.

[0045] The leuco dye may be selected from spiroxazines, naphthopyrans, phthalides, fluorans, triarylmethanes, benzoxazines, quinazolines, spiropyrans, quinones, tetrazolium salts, thiazines, phenazines, and oxazines, some of which are disclosed in WO 2006 / 108745, the contents of which are incorporated herein by reference. Examples of suitable leuco dyes are also included in WO 2015 / 015200 and WO 2013 / 068729, the contents of which are incorporated herein by reference.

[0046] With respect to the second to thirteenth aspects of the present invention, the leuco dye may also be 2'-anilino-6'-(dibutylamino)-3'-methyl-3H-spiro[2-benzofuran-1,9'-xanthene]-3-one (CAS No. 89331-94-2), 6'-(diethylamino)-3'-methyl-2'-(phenylamino)spiro[2-benzofuran-3,9'-xanthene]-1-one (CAS No. 29512-49-0), 2-anilino-6'-[ethyl(p-toyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS No. 59129-79-2), Blue 3-CVL 6-(dimethylamino)-3,3-bis-[4-(dimethylamino)phenyl]phthalide (CAS number 1522-42-7), Blue-4 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline] (CAS number 67707-04-4), Red-5 3,3'-bis(1-n-octyl-2-methylindol-3-yl)phthalide (CAS number 50292-95-0), Orange-6 6'-(diethylamino)-3-oxo-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-2'-carboxylic acid ethyl ester (CAS number 154306-60-2), Blue-8 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl-1-octyl-1H-indol-3-yl)furo[3,4-b]pyridin-5(7H)-one (CAS number 87563-89-1), Green-9 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS number 34372-72-0), Yellow-10 N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl]-benzenamine (CAS number 144190-25-0), Black-15 6'-(diethylamino)-2'-[(dimethylphenyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS number 36431-22-8), keto acid-1 4-(N,N-diethylamino)-2-hydroxy-2'-carboxybenzophenone (CAS number 5809-23-4), keto acid-2 4-(N,N-dibutylamino)-2-hydroxy-2'-carboxybenzophenone (CAS number 54574-82-2).

[0047] Suitable sources of leuco dyes include, but are not limited to: Yamada Chemical Co., Ltd., Chameleon Specialty Chemicals, Inc., and Connect Chemicals.

[0048] The leuco dye may be present in any suitable amount in the second composition utilized in the second, third, fourth, fifth, tenth or twelfth aspects of the present invention, or in the leuco dye-comprising composition utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the present invention. The leuco dye is preferably present in the second composition or leuco dye-comprising composition in an amount of 4 to 30 wt. % of the second composition or composition, for example 5 to 30 wt. %, or 5 to 20 wt. %, or 6 to 20 wt. % of the second composition or leuco dye-comprising composition.

[0049] With respect to the second to fifth, tenth and twelfth aspects of the present invention, the thermal acid generator may be selected from suitable thermal acid generators including, but not limited to, the following: 4-hydroxyphenyl-4'-isopropoxyphenyl sulfone (Chameleon Developer-1); N-(p-toluenesulfonyl)-N'-(3-(p-toluenesulfonyloxy)phenyl)urea (Pergafast 201); 1,1,1-tris(4-hydroxyphenyl)ethane (THPE) and amine salts of organometallic compounds.

[0050] With regard to the second to fifth, tenth and twelfth aspects of the present invention, the thermal acid generator is preferably an amine salt of an organometallic compound.

[0051] With respect to the second to thirteenth aspects of the present invention, the amine salt of the organometallic compound is represented by formula (I):

[0052] [ka] wherein X is silicon or boron, and E and F are the same or different:

[0053] [ka] is selected from the group consisting of where R 6 and R 7 may be the same or different, hydrogen, C 1~4 -Alkyl, C 1~4 -alkoxy, halogen, amino or carboxy, When X=silicon, o=1 and p=0, and R 1 is aryl, aralkyl or C 1~4 - alkyl, or o=1 and p=1, and R 1 and R 2 And together they are:

[0054] [ka] and forming one residue selected from the group consisting of: when X=boron, o=0 and p=0, and R 3 , R 4 and R 5 are the same or different, hydrogen, C 1~12 -Alkyl, C 1~6 -hydroxyalkyl, allyl, aralkyl or arylsulfonyl, wherein aralkyl or arylsulfonyl is C 1~4 -alkyl or R 3 and R 4 together with the nitrogen to which they are attached form a morpholino or piperidino ring) It can be of the following type.

[0055] C 1~4Examples of -alkyl are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl and tert-butyl. 1~4 Examples of -alkoxy are methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, isobutoxy, and tert-butoxy. Examples of halogen are chlorine, bromine, fluorine, and iodine. Examples of aryl are phenyl, 1-naphthyl, 2-naphthyl, and pyridyl. Examples of aralkyl are benzyl and 2-phenylethyl. C 1~12 Examples of -alkyl are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl and dodecyl. 1~6 Examples of -hydroxyalkyl are hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 5-hydroxypentyl and 6-hydroxyhexyl. Examples of arylsulfonyl are phenylsulfonyl and tosyl.

[0056] When X is silicon, preferably E and F are the same or different and are selected from a, b, c, d and e, where R 6 and R 7 may be the same or different, hydrogen, C 1~4 -Alkyl, C 1~4 -alkoxy, halogen, amino or carboxy, o=1 and p=0, and R 1 is aryl, aralkyl or C 1~4 - alkyl, or o=1 and p=1, and R 1 and R 2 Together with 1 , b 1 , c 1 , d 1 , and e 1 and forming one residue selected from R 3 , R 4 and R5 are the same or different, hydrogen, C 1~12 -Alkyl, C 1~6 -hydroxyalkyl, allyl, aralkyl or arylsulfonyl, wherein aralkyl or arylsulfonyl is C 1~4 -alkyl or R 3 and R 4 together with the nitrogen to which they are attached form a morpholino or piperidino ring; Optionally, if E and F are both residues a, then o=1 and p=1, and R 1 and R 2 are taken together to form residue a 1 In this case, R 3 , R 4 and R 5 are not all ethyl.

[0057] When X is silicon, more preferably, E and F are the same or different and are selected from a, b, c, d and e, where R 6 and R 7 may be the same or different and may be hydrogen or C 1~4 -alkyl, o=1 and p=0, and R 1 is aryl, o=1 and p=1, and R 1 and R 2 together, a 1 , b 1 , c 1 , d 1 , and e 1 and forming one residue selected from R 3 , R 4 and R 5 are the same or different, hydrogen, C 1~10 -Alkyl, C 1~6 -hydroxyalkyl, allyl, or arylsulfonyl, where arylsulfonyl is C 1~4 -alkyl or R 3 and R 4may be taken together with the nitrogen to which they are attached to form a morpholino or piperidino ring.

[0058] C 1~10 Examples of -alkyl are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl and decyl.

[0059] When X is silicon, more preferably E and F are the same and selected from a, b, c, where R 6 and R 7 is hydrogen, o=1 and p=0, and R 1 is phenyl, o=1 and p=1, and R 1 and R 2 together, a 1 , b 1 , and c 1 and forming one residue selected from R 3 , R 4 and R 5 are the same or different, hydrogen, C 1~8 - alkyl or aryl, or R 3 and R 4 taken together with the nitrogen to which they are attached form a morpholino ring.

[0060] C 1~8 Examples of -alkyl are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl, octyl and 2-ethylhexyl.

[0061] When X is silicon, the amine salt of the organometallic compound of formula (I) is:

[0062] [ka]

[0063] [ka]

[0064] [ka] may be selected from the group consisting of:

[0065] When X is boron, E and F are the same or different and are selected from a, b, f, g, and h, where R 6 and R 7 may be the same or different, hydrogen, C 1~4 -Alkyl, C 1~4 -alkoxy, halogen, amino or carboxy, o=0 and p=0, and R 3 , R 4 and R 5 are the same or different, hydrogen, C 1~12 -Alkyl, C 1~6 -hydroxyalkyl, allyl, aralkyl or arylsulfonyl, wherein aralkyl or arylsulfonyl is C 1~4 -alkyl or R 3 and R 4 together with the nitrogen to which they are attached form a morpholino or piperidino ring, Optionally, if E and F are both residues a, and o=0 and p=0, then R 3 , R 4 and R 5 However, they are not all butyl.

[0066] When X is boron, preferably E and F are the same or different and are selected from a, b, and f, where R 6 and R 7 is hydrogen, o=0 and p=0, and R 3 , R 4 , and R5 are the same or different, hydrogen, C 1~8 It is alkyl or aryl.

[0067] When X is boron, the amine salt of the organometallic compound of formula (I) is:

[0068] [ka]

[0069] [ka]

[0070] [ka] is selected from the group consisting of:

[0071] With respect to the second through thirteenth aspects of the present invention, the thermal acid generator may be an amine salt of borobenzilate and tri-n-butylammonium borodisalicylate, such as tri-n-butylammonium-4,4'-dioxo-4H,4'H-2,2'-spirobi[benzo[d][1,3,2]dioxaborinine]-2-uidate with N,N-dibutyl-1-butanamine, N,N-dibutylbutan-1-aminium bis[2-(hydroxy-kO)benzoato(2-)-kO]borate(1-), or hydrogen bis[2-(hydroxyl-kappaO)benzoate(2-)-kappaO]-(T-4)-borate(1-) compound (1:1:1).

[0072] For the second through thirteenth aspects of the present invention, the thermal acid generator is preferably hydrogen bis[2-(hydroxyl-kappa O)benzoate(2-)-kappa O]-(T-4)-borate(1-) compound (1:1:1) with N,N-dibutyl-1-butanamine, which may be known as SABoTBA. This compound has CAS number 22450-96-0.

[0073] The thermal acid generator acts as a color developer, and when a composition containing the thermal acid generator is irradiated using a laser, it generates an acid that reacts with the leuco dye to form a color, thereby displaying a mark or image.

[0074] With respect to the second to thirteenth aspects of the present invention, the thermal acid generator may be present in any suitable amount in the second composition or the leuco dye-containing composition described in detail herein. The thermal acid generator may be present in the second composition or the leuco dye-containing composition in an amount of 5 to 40 wt.%, such as 7 to 30 wt.%, or 10 to 30 wt.%, preferably 15 to 25 wt.%.

[0075] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, may be a water-based composition and further comprise water. In the context of the present invention, a water-based composition comprises less than 5 wt.%, less than 3 wt.%, or the like, of an organic solvent. It is preferred that no organic solvent be used as a component in the formulation process of a water-based composition. When the second composition or the leuco dye-containing composition further comprises water, the water may be present in the second composition or the leuco dye-containing composition in an amount of 15 to 65 wt.%, 20 to 55 wt.%, or the like.

[0076] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, may be an organic solvent-based composition and may further comprise an organic solvent. Two or more organic solvents may be utilized. With respect to such compositions, it is understood that water is not utilized as an ingredient in formulating the composition. Suitable organic solvents include, but are not limited to, alcohols and acetates: ethanol, benzyl alcohol, butanol, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, 2-butoxyethanol acetate, 2-butoxyethyl acetate, 1-methoxy-1-methylethyl acetate, cyclohexanone, solvent naphtha petroleum, xylene, 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, ammonium salts of carbonates, and combinations thereof, preferably, alcohols and acetates: ethanol, benzyl alcohol, butanol, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, acetic acid The organic solvent may be selected from 2-butoxyethanol, 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, ammonium salts of carbonates, and combinations thereof, more preferably an alcohol and an acetate selected from the following: 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, or an ammonium salt of carbonate, or combinations thereof, more preferably a combination of 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, and an ammonium salt of carbonate. The organic solvent may be polar or non-polar.When the second composition or the composition comprising a leuco dye is an organic solvent-based composition and further comprises organic solvent(s), the organic solvent(s) may be present in the second composition or the composition comprising a leuco dye in an amount of 20 to 75 wt.%.

[0077] If the second composition or the composition comprising a leuco dye further comprises organic solvent(s), the organic solvent(s) may be: those available under the trade name Tampoprint®, commercially available from TAMPOPRINT GmbH and TAMPOTECH Ltd, such as Tampoprint® ACP ​​(Tampoprint® Transparent Lacquer ACP), Tampoprint® K-VDS Thinner, and Tampoprint® K-VDL Thinner; those available under the trade name Tampa®, commercially available from Marabu-Inks, such as Tampa® Pol TPY, Tampa® Plus TPL, and Tampa® Star TPR; those available under the trade name Mara®, commercially available from Marabu-Inks, such as Mara® Prop PP; T120, commercially available from RUCOINX; Series, commercially available from Printcolor 786; and TPC 630, commercially available from Teca-Print, may be incorporated into the second composition or the composition containing the leuco dye using commercially available formulations such as, but not limited to, TPC 630, commercially available from Teca-Print.

[0078] It will be understood by those skilled in the art that when the second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or a composition comprising a leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the invention, is applied to a plastic substrate, some or all of the water or organic solvent may be lost by the application methods detailed herein, leaving behind no water or organic solvent, or only residues thereof, or low levels of water or organic solvent.

[0079] Alternatively, the second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the invention, may not further comprise water or an organic solvent, i.e., may not be a water-based or organic solvent-based composition. The second composition or the leuco dye-containing composition may instead be cured by ultraviolet radiation.

[0080] The second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the present invention is preferably an organic solvent-based composition when the colored compound is a leuco dye.

[0081] The composition containing the leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspect of the present invention contains an organic solvent and is an organic solvent-based composition.

[0082] It is surprising and advantageous that leuco dyes can be utilized as coloring compounds when formulated in organic solvents, i.e., organic solvent-based compositions.

[0083] Color formation by leuco dyes is facilitated through interaction with a thermal acid generator, or "developer." In laser-reactive compositions, irradiation with a laser creates an acidic state, resulting in the interaction of the two components and the leuco dye displaying color. However, problems arise when such components are utilized in organic solvent-based compositions. In organic solvent-based laser-reactive compositions containing a leuco dye and a thermal acid generator, the leuco dye and the thermal acid generator may interact prematurely with the organic solvent, resulting in premature color formation during standard formulation of the composition (during stirring, mixing, blending, processing, and storage) prior to application to a substrate. Consequently, significant background coloration occurs, preventing the formation of a recognizable, identifiable mark or image. To avoid such negative interactions, previously utilized organic solvent-based compositions have required the use of small amounts of leuco dye and thermal acid generator (solid components) and large amounts of organic solvent to ensure the leuco dye and the thermal acid generator are solubilized in the organic solvent. However, such compositions are not suitable for commercial purposes, requiring excessively high and impractical wet coating weights to produce a recognizable and identifiable mark or image. Known organic solvent-based compositions are therefore not commercially viable for processes that affect marks or images on a substrate in forming variable information thereon. Moreover, given the small solid components of leuco dyes and thermal acid generators present, any marks or images formed by these known compositions will fade over time.

[0084] However, the present inventors have been able to provide a composition comprising a leuco dye and a thermal acid generator in an organic solvent that does not react prematurely during formulation and that can form a recognizable and identifiable mark or image when applied to or incorporated into a plastic substrate only when desired. This advantageously allows an organic solvent-based composition comprising a leuco dye to be applied to or incorporated into a plastic substrate and used to form a mark or image on the substrate, which is also compatible with the recycling process described herein.

[0085] When applying the compositions of the present invention to plastic substrates, it is desirable to use a leuco dye as the coloring compound. This is particularly advantageous because leuco dyes can produce colors other than black, thereby providing a novel method for plastic substrates to achieve a color appearance other than black, which can then be recycled as described above, providing uncontaminated plastic materials and waste streams. Furthermore, it is typically desirable to use an organic solvent-based composition containing a leuco dye compared to an aqueous composition containing a leuco dye, because the organic solvent-based composition provides a higher quality, smoother composition on the plastic substrate after application (visual consideration) due to its lower surface tension, is more robust (improved environmental resistance, such as abrasion resistance and chemical resistance), and has a faster drying time after application to the plastic substrate.

[0086] Moreover, the inventors have advantageously found that by allowing the leuco dye to be introduced onto a plastic substrate, when the mark or image formed by the leuco dye is exposed to an alkaline aqueous solution, the alkaline conditions of the alkaline aqueous solution cause the leuco dye to return to the colorless form it had prior to interaction with the thermal acid generator while the mark or image is being removed from the plastic substrate. This is highly advantageous in a method for removing a mark or image from a plastic substrate, as the color of the mark or image is lost and any staining of the plastic material is avoided, as described herein.

[0087] Advantageous use of a leuco dye and a thermal acid generator in an organic solvent-based composition can be achieved through the selection of a thermal acid generator that is a thermal acid generator selected from amine salts of organometallic compounds, and the presence of an alkaline stabilizer having a pKa of 2 to 12 in the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the invention, or a composition containing a leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the invention. Without being bound by theory, the inventors believe that this selection of alkaline stabilizer and thermal acid generator prevents any acetate, alcohol, or acid groups that may be found in the organic solvent from initiating a reaction with the leuco dye and causing premature color formation.

[0088] The presence of an alkaline stabilizer with a pKa of 2 to 12 in the second composition or composition containing the leuco dye allows the leuco dye and thermal acid generator (solid components) to disperse rather than solubilize in the organic solvent. Thus, higher concentrations of these two components (leuco dye and thermal acid generator) can be utilized, resulting in a lower wet coating weight required to achieve a recognizable and identifiable mark or image. Such a manufacturing process is commercially viable, and the increased component concentrations mean that the stability of the mark or image can be maintained over time.

[0089] Thus, the second composition or composition containing a leuco dye contains a greater amount of leuco dye and thermal acid generator (solid components) than previously known, but less preferred, organic solvent compositions containing a leuco dye and a thermal acid generator.

[0090] In the second composition used in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition used in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, the composition preferably contains 9 to 70 wt % of the leuco dye and the thermal acid generator, for example, 12 to 60 wt %, or 15 to 50 wt %, or 21 to 45 wt % of the leuco dye and the thermal acid generator. The leuco dye and the thermal acid generator are solid components, i.e., in a solid form.

[0091] In the second composition used in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition used in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, the composition preferably contains 25 to 70 wt % of the solid form components, such as 30 to 70 wt %, for example, 35 to 70 wt %, or 40 to 65 wt %, or 45 to 60 wt % of the solid form components. The second composition used in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition used in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, can be said to have a solid content of 25 to 70 wt %, 30 to 70 wt %, for example, 35 to 70 wt %, or 40 to 65 wt %, or 45 to 60 wt %.

[0092] Thus, preferably, the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention comprises a leuco dye, a thermal acid generator selected from amine salts of organometallic compounds, an organic solvent, and an alkaline stabilizer having a pKa of 2 to 12. Such second compositions advantageously enable the use of the organic solvent-based compositions containing the leuco dye of the present invention described above.

[0093] With respect to the use according to the seventh aspect of the present invention, the plastic substrate may be as defined herein in relation to the third aspect of the present invention (the leuco dye-containing composition and the second composition being used interchangeably), it being understood that the plastic substrate displays a mark or image, said mark or image being formed by irradiating a localized location of the second composition or the leuco dye-containing composition using a laser.

[0094] With respect to the second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the invention, it is preferred that the alkaline stabilizer has a pKa of 4 to 11, such as 6 to 11, for example 6 to 10.5.

[0095] The pKa value is the acid dissociation constant (K a ) The pKa value is:

[0096]

number

[0097] With respect to the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, the alkaline stabilizer having a pKa of 2 to 12 may be selected from, but is not limited to, the following: sodium carbonate, sodium bicarbonate, potassium carbonate, monoethanolamine, and triethanolamine, or combinations thereof. Preferably, the alkaline stabilizer having a pKa of 2 to 12 is selected to be sodium bicarbonate.

[0098] The alkaline stabilizer having a pKa of 2 to 12 may be present in any suitable amount in the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or in the composition containing a leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention. The alkaline stabilizer having a pKa of 2 to 12 may be present in the second composition or the composition containing a leuco dye in an amount of 0.1 to 6 wt.%, 0.5 to 3 wt.%, or the like.

[0099] When present in an organic solution, the alkaline stabilizer having a pKa of 2 to 12, the leuco dye, and the thermal acid generator utilized in the second composition of the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition of the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, are dispersed, not dissolved, in the organic solution prior to application to the plastic substrate and irradiation of the substrate, thereby preventing premature color formation.

[0100] The advantageous use of leuco dyes and thermal acid generators in organic solvent-based compositions, such as those comprising the leuco dyes utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, can be further achieved through the selection of the organic solvent used. The selected organic solvent(s) also allow the leuco dye and thermal acid generator (solid components) to be dispersed, rather than solubilized, in the organic solvent. Suitable organic solvents include, but are not limited to, alcohols and acetates: ethanol, benzyl alcohol, butanol, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, 2-butoxyethanol acetate, 2-butoxyethyl acetate, 1-methoxy-1-methylethyl acetate, cyclohexanone, solvent naphtha petroleum, xylene, 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, ammonium salts of carbonates, and combinations thereof, preferably, alcohols and acetates: ethanol, benzyl alcohol, butanol, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, acetic acid The organic solvent may be selected from 2-butoxyethanol, 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, ammonium salts of carbonates, and combinations thereof, more preferably an alcohol and an acetate selected from the following: 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, or an ammonium salt of carbonate, or combinations thereof, more preferably a combination of 2-ethoxy-1-methylethyl acetate, n-butyl acetate, 2-methoxy-1-methylethyl acetate, 2-butoxyethyl acetate, 4-hydroxy-4-methylpentan-2-one, and an ammonium salt of carbonate. The organic solvent may be polar or non-polar.When the second composition or the composition comprising a leuco dye is an organic solvent-based composition and further comprises organic solvent(s), the organic solvent(s) may be present in the second composition or the composition comprising a leuco dye in an amount of 20 to 75 wt.%.

[0101] If the second composition or the composition comprising a leuco dye further comprises organic solvent(s), the organic solvent(s) may be: those available under the trade name Tampoprint®, commercially available from TAMPOPRINT GmbH and TAMPOTECH Ltd, such as Tampoprint® ACP ​​(Tampoprint® Transparent Lacquer ACP), Tampoprint® K-VDS Thinner, and Tampoprint® K-VDL Thinner; those available under the trade name Tampa®, commercially available from Marabu-Inks, such as Tampa® Pol TPY, Tampa® Plus TPL, and Tampa® Star TPR; those available under the trade name Mara®, commercially available from Marabu-Inks, such as Mara® Prop PP; T120, commercially available from RUCOINX; Series, commercially available from Printcolor 786; and TPC 630, commercially available from Teca-Print, may be incorporated into the second composition or the composition containing the leuco dye using commercially available formulations such as, but not limited to, TPC 630, commercially available from Teca-Print.

[0102] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, may further comprise a binder. Suitable binders include, but are not limited to, styrene acrylate, polyvinyl butyral, nitrocellulose, polyurethane, acrylic, polyvinyl chloride, polyvinyl acetate, polyamide, alkyd, cellulose acetate butyrate, polyester, melamine-based resin, and epoxy-based resin, or combinations thereof. Preferably, the binder is a polyester. The binder may be present in the second composition or compositions in an amount of 5 to 55 wt.%, 10 to 50 wt.%, etc.

[0103] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, is insoluble in water. The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, is insoluble in alkaline aqueous solutions. Therefore, it does not dissolve in the alkaline aqueous solutions utilized in mark or image removal. Therefore, it can be removed from the resulting plastic material or waste stream to prevent contamination of these. When the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, further comprises a binder, the binder is insoluble in water.

[0104] If the second composition or the composition containing a leuco dye further comprises a binder, the binder may be introduced into the second composition or the composition containing a leuco dye using a commercially available formulation, such as, but not limited to, those available under the Tampoprint® trade name, commercially available from TAMPOPRINT Germany, such as Tampoprint® ACP ​​(Tampoprint® Transparent Lacquer ACP); those available under the Tampa® trade name, commercially available from Marabu-Inks, such as Tampa® Pol TPY, Tampa® Plus TPL, and Tampa® Star TPR; those available under the Mara® trade name, commercially available from Marabu-Inks, such as Mara® Prop PP; T120, commercially available from RUCOINX; Series 786, commercially available from Printcolor; and TPC 630, commercially available from Teca-Print.

[0105] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the composition comprising a leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, may further comprise a near-infrared absorbing compound capable of enhancing absorption of near-infrared or infrared radiation. Suitable near-infrared absorbing compounds include: inorganic copper salts, such as copper(II) hydroxyl phosphate; organic NIR dyes and pigments, such as N,N,N',N'-tetrakis(4-dibutylaminophenyl)-p-benzoquinone bis(iminium hexafluoroantimonate); non-stoichiometric, reduced, or doped inorganic compounds, such as reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide (tungsten bronze), and compounds of the formula M x W y O z(wherein M is at least one element selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; and W is tungsten. and 2.2≦z / y≦3.0); conductive polymers, such as polystyrene sulfonate (PEDOT); and combinations thereof. Near-infrared absorbing compounds include, but are not limited to, inorganic copper salts, such as copper(II) hydroxyl phosphate; non-stoichiometric, reduced or doped inorganic compounds, such as reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide (tungsten bronze), and inorganic compounds of the formula M x W y O z wherein M is at least one element selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; and O is oxygen, and is preferably selected from reduced and doped tungsten oxide, reduced antimony tin oxide, or doped metal oxides, such as aluminum-doped zinc oxide (AZO) and fluorine-doped tin oxide (FTO), including inorganic compounds of the formula: The near infrared absorbing compound can be present in the second composition or the composition including the leuco dye in an amount of 0.1 to 10 wt. %, 0.2 to 5 wt. %, etc.

[0106] Those skilled in the art will understand that highly colored (highly visible) near-infrared absorbers, such as carbon black, are not suitable for the second composition or leuco dye-containing composition utilized in the present invention. Such highly colored near-infrared absorbers create a strongly colored background for such compositions. In contrast, the second composition or leuco dye-containing composition utilized in the present invention can be transparent or translucent when applied to a substrate, so that effective mark or image formation can occur upon irradiation using a laser. Therefore, near-infrared absorbers with inconspicuous colors are required. Highly colored near-infrared absorbers are detrimental to the present invention. "Visibility," in this context, means visibility by the human eye and / or machine readability. Preferably, the near-infrared absorber is not a highly visible near-infrared absorbing compound. Preferably, the near-infrared absorbing compound is not a highly visible pigment or dye. Preferably, the second composition or leuco dye-containing composition does not contain carbon black.

[0107] When the second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, further comprises a near-infrared absorber, the second composition or the leuco dye-containing composition may further comprise an agent operable to transfer heat from the near-infrared absorber to the colored compound or leuco dye, i.e., a heat transfer agent. The heat transfer agent may be a metal oxide, metal pyrophosphate, or metal phosphate of the following metals: iron, aluminum, zirconium, titanium, or a combination thereof. Preferably, the heat transfer agent is a metal oxide, metal pyrophosphate, or metal phosphate of the following metals: iron, aluminum, zinc, zirconium, titanium, or a combination thereof. Those skilled in the art will understand that references to metal oxides, metal pyrophosphates, or metal phosphates should also be interpreted to include hydrates of any given metal oxide, metal pyrophosphate, or metal phosphate. The heat transfer agent may be selected from iron (III) pyrophosphate hydrate, zinc aluminum oxide, zirconium (IV) oxide, zirconium dioxide, aluminum oxide, iron phosphate dihydrate, and titanium dioxide. More preferably, the heat transfer agent is selected from iron (III) pyrophosphate hydrate, zinc aluminum oxide, zirconium dioxide, zirconium (IV) oxide, aluminum oxide, zinc oxide, iron phosphate dihydrate, and titanium dioxide. Even more preferably, the heat transfer agent is a metal oxide. The heat transfer agent may be a metal oxide of iron, aluminum, zirconium, and titanium, or a combination thereof. Even more preferably, the heat transfer agent is a metal oxide of iron, aluminum, zinc, zirconium, and titanium, or a combination thereof. The heat transfer agent may be selected from zirconium (IV) oxide, zirconium dioxide, aluminum oxide, and titanium dioxide. Even more preferably, the heat transfer agent is selected from zinc aluminum oxide, zirconium dioxide, zirconium (IV) oxide, aluminum oxide, zinc oxide, and titanium dioxide. Most preferably, the heat transfer agent is zirconium (IV) oxide.

[0108] The second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the invention may further comprise an additive or combination of additives.

[0109] Suitable additives are well known to those skilled in the art. Examples of suitable additives include, but are not limited to, polymers; light or energy absorbers; UV absorbers; surfactants; wetting agents; dispersants; defoamers; flow and leveling agents; friction coefficient surface modifiers; waxes; drying accelerators; colorants; gloss or matte enhancers; rubbing, mar and wear modifiers; fluorescent agents; plasticizers; optical brighteners; oxidizing or reducing agents; stabilizers; light stabilizers such as hindered amines; rheology modifiers such as thickeners or diluents; humectants; solvents; adhesion promoters; acid or base scavengers; retarders; defoamers; antifoaming agents; and combinations thereof. The additive or additive combination may be present in the second composition or composition in an amount of 0.1 to 15 wt.%, preferably 0.5 to 5 wt.%.

[0110] The second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the invention, or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh or thirteenth aspects of the invention, is preferably pigment-free.

[0111] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention or the leuco dye-containing composition utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention is not soluble in aqueous alkaline solutions used for mark or image removal as detailed herein, and the second composition or the leuco dye-containing composition remains as a solid or precipitate after exposure to aqueous alkaline solutions.

[0112] The first composition is at least partially soluble in the aqueous alkaline solution used to remove the mark or image, as described herein. This means that the first composition separates from the plastic substrate upon exposure to the aqueous alkaline solution, and also promotes the separation of the second composition or the composition containing the leuco dye from the plastic substrate, thereby promoting the removal of the mark or image from the plastic substrate. It is also understood that the first composition separates from the second composition or the composition containing the leuco dye, given its at least partial solubility in the aqueous alkaline solution.

[0113] Upon exposure to the alkaline aqueous solution, the time it takes for the first composition to at least partially solubilize can be from 1 to 45 minutes, such as from 1 to 30 minutes, or from 1 to 20 minutes, such as from 1 to 15 minutes, preferably from 1 to 5 minutes. Preferably, the first composition solubilizes within 45 minutes, preferably within 20 minutes, preferably within 15 minutes, more preferably within 5 minutes after exposure to the alkaline aqueous solution.

[0114] In the context of the present invention, the first composition is solubilized in an alkaline aqueous solution, resulting in the first composition separating from the plastic substrate (the bond with the plastic substrate is broken). Thus, the first composition causes the second composition or compositions to separate from the plastic substrate. It is understood that the first composition may be partially or fully solubilized when exposed to an alkaline aqueous solution, or may have some degree of solubility in the alkaline aqueous solution.

[0115] The use of proteins in the first compositions utilized in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the invention is advantageous because proteins are environmentally friendly, biodegradable materials, and therefore pose no threat to the environment when washed into the waste stream during removal of the mark or image from the plastic substrate, as detailed herein.

[0116] The protein acts as a binder for the first composition. It is the protein that allows the first composition to be at least partially solubilized in an alkaline aqueous solution and separated from the plastic substrate (and the second composition or compositions). The protein of the first composition is at least partially soluble in an alkaline aqueous solution. Upon contact with an alkaline aqueous solution, the protein decomposes into its constituent amino acid monomers (basic units). Thus, when exposed to an alkaline aqueous solution, the first composition at least partially solubilizes in the alkaline aqueous solution, facilitating the separation of the second composition or the composition containing the leuco dye from the plastic substrate and removing the mark(s) or image(s).

[0117] With respect to the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention, the protein of the first composition may be any suitable protein. The protein is in its natural state. The protein is not denatured. The protein is not modified from its natural state. The protein may be sourced from a variety of natural sources, including animal, dairy, and vegetable proteins. Preferably, the protein is selected from animal or vegetable proteins. Vegetable proteins are more preferably selected due to their biodegradable and environmentally friendly properties. Examples of animal proteins include, but are not limited to: collagen (hydrolyzed or non-hydrolyzed), such as hydrolyzed bovine collagen; and gelatin. Examples of dairy proteins include, but are not limited to: egg white; whey; and casein. Examples of vegetable proteins include, but are not limited to: gluten, zein, prolamin proteins such as soy, pea, and hemp.

[0118] Preferably, the protein is selected from prolamin proteins, more preferably from zein or soy, and preferably is zein.

[0119] All references herein to specific proteins refer to the protein itself and should be taken to include, where appropriate, derivatives such as peptides or functional proteins.

[0120] The protein may be present in any suitable amount in the first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention. Preferably, the protein may be present in the first composition in an amount of 0.1 to 50 wt.%, 0.1 to 40 wt.%, or even 3 to 30 wt.%. More preferably, the protein may be present in the first composition in an amount of 5 to 25 wt.%.

[0121] During formulation of the first composition and prior to application of the first composition to the plastic substrate, the protein is solubilized in the first composition. It is understood that different proteins solubilize at different pHs. Therefore, the pH of the first composition may vary as the solubility of different proteins varies. Some proteins are more soluble at higher or lower pHs. The first composition preferably has a pH of 2 to 12.5, preferably 3 to 11.5. The first composition may comprise a neutral medium, i.e., the resulting composition has a pH of about 7.

[0122] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may comprise an aqueous medium in which the protein is soluble when the first composition is formulated and before the first composition is applied to the plastic substrate. The first composition may comprise an alkaline aqueous medium such as water containing ammonia, monoethanolamine, or other amine-based material, and a carbonate salt. This may be formed by adding an aqueous solution containing ammonia, monoethanolamine, or other amine-based material, and a carbonate salt to water. The first composition may also comprise an acidic aqueous medium such as acetic acid, hydrochloric acid, and other acidic chemicals. Preferably, the first composition comprises an alkaline aqueous medium such as water containing ammonia, monoethanolamine, or other amine-based material, and a carbonate salt, preferably monoethanolamine.

[0123] Alternatively, the first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may include a solvent in which the protein is soluble when the first composition is formulated and before the first composition is applied to the plastic substrate. The first composition may include a single solvent or a mixture of solvents. The solvent may include water, an organic solvent, a mixture of water and an organic solvent, or a mixture of organic solvents. A base such as ammonia, monoethanolamine, or other amine-based material and a carbonate may optionally be present in the solvent. Suitable organic solvents include, but are not limited to, the following: alcohols such as ethanol, n-propanol, isopropanol, and n-butanol; esters such as ethyl acetate, butyl acetate, and n-hexyl acetate; aromatic hydrocarbons such as benzene, toluene, xylene, and solvent naphtha 100, 150, and 200; ketones such as acetone, cyclohexanone, methyl isobutyl ketone, and methyl ethyl ketone; glycols such as butyl glycol; glycol ethers such as methoxypropanol, ethylene glycol monomethyl ether, and ethylene glycol monobutyl ether; and combinations thereof. Preferably, the first composition contains water and / or an organic solvent. More preferably, the first composition contains water and / or an alcohol, an acetate ester, or a ketone. More preferably, the first composition contains water and / or an alcohol or a ketone. More preferably, the first composition contains water and / or an alcohol. More preferably, the first composition contains water and / or ethanol.

[0124] The aqueous medium or solvent is preferably present in the first composition utilised in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention in an amount of 15 to 95 wt%, for example 15 to 80 wt.%, or such as 15 to 70 wt%, such as 15 to 60 wt%, or even 20 to 55 wt%.

[0125] It will be understood by those skilled in the art that the protein is solubilized in the aqueous medium or solvent of the first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention during formulation of the first composition and before application of the first composition to a plastic substrate. The aqueous medium or solvent, and any components thereof, are present at a level such that the protein remains solubilized in the solvent or aqueous medium during formulation and before application of the first composition to a plastic substrate. It will be understood that the majority of the aqueous medium or solvent is lost upon application to a plastic substrate by the application methods detailed herein.

[0126] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may further comprise a biocide, such as an isothiazolinone, a cationic quaternary salt, e.g., ammonium / phosphonium, an amine, a urea, or a benzoate / sorbate. Two or more biocides may be present in the first composition. Biocides improve protein stability, i.e., shelf life, and include surfactants with biocidal properties and protein stabilizing capabilities. Examples of surfactants include, but are not limited to, alkyl sulfates, e.g., dioctyl sodium sulfosuccinate (DSS), sodium xylene sulfonate, sodium lauryl sulfate (SLS), and sodium dodecyl sulfate (SDS); carboxylates, e.g., sodium stearate; sorbates, e.g., sodium sorbate (SS); polysorbates, e.g., polysorbate 20 (also known as Tween 20); amine oxides, e.g., lauryl dimethylamine oxide; and phosphate esters. Moreover, non-traditional biocides may be used, i.e., preservatives typically used in foodstuffs, such as sodium nitrate / nitrite, lauryldimethylamine oxide (LDAO), ascorbic acid, etc. The first composition may comprise 0.001 to 5 wt%, such as 0.1 to 5 wt%, or even 0.1 to 1 wt%, preferably 0.1 to 0.5 wt%, of the biocide.

[0127] As described above, the protein in the first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention functions as a binder. Therefore, the first composition typically does not contain a binder in addition to the protein. However, alternatively, to further improve the binding strength of the first composition to the substrate, the first composition may contain a binder in addition to the protein. Suitable binders are well known to those skilled in the art. Examples of suitable binders include, but are not limited to, the following: natural products and their derivatives, including natural resins such as shellac; and combinations thereof. The binder can be present in any suitable amount in the first composition. Preferably, the first composition contains 1 to 40 wt %, 3 to 30 wt %, and most preferably 5 to 20 wt % of the binder.

[0128] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may further comprise a near-infrared absorbing compound capable of enhancing absorption of near-infrared or infrared radiation. Suitable near-infrared absorbing compounds include: inorganic copper salts, such as copper(II) hydroxyl phosphate; organic NIR dyes and pigments, such as N,N,N',N'-tetrakis(4-dibutylaminophenyl)-p-benzoquinone bis(iminium hexafluoroantimonate); non-stoichiometric, reduced or doped inorganic compounds, such as reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide (tungsten bronze), and compounds of the formula M x W y O z(wherein M is at least one element selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; and W is tungsten. and 2.2≦z / y≦3.0); conductive polymers, such as polystyrene sulfonate (PEDOT); and combinations thereof. Near-infrared absorbing compounds include, but are not limited to, inorganic copper salts, such as copper(II) hydroxyl phosphate; non-stoichiometric, reduced or doped inorganic compounds, such as reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide (tungsten bronze), and inorganic compounds of the formula M x W y O z wherein M is at least one element selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; and O is oxygen, and is preferably selected from reduced and doped tungsten oxide, reduced antimony tin oxide, or doped metal oxides, such as aluminum-doped zinc oxide (AZO) and fluorine-doped tin oxide (FTO), including inorganic compounds of the formula:

[0129] Those skilled in the art will understand that highly colored (highly visible) near-infrared absorbers, such as carbon black, are not suitable for the first composition of the present invention. Such highly colored near-infrared absorbers create a strongly colored background in the first composition. In contrast, the first compositions of the present invention utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention can be transparent or translucent when applied to a substrate. Therefore, a near-infrared absorber with an inconspicuous color is required, so that effective mark or image formation can occur upon irradiation using a laser. Highly colored near-infrared absorbers are detrimental to the present invention. "Visibility," in this context, means visibility by the human eye and / or machine readability. Preferably, the near-infrared absorber is not a highly visible near-infrared absorbing compound. Preferably, the near-infrared absorbing compound is not a highly visible pigment or dye. Preferably, the first composition does not contain carbon black.

[0130] The first composition used in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention may contain 0.05 to 25 wt %, 0.05 to 20 wt %, etc. of a near-infrared absorbing agent.

[0131] The near-infrared absorbent used in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may have any suitable D50 particle size distribution value. The D50 particle size distribution value of the near-infrared absorbent is preferably 5 μm or less. More preferably, the D50 particle size distribution value of the near-infrared absorbent is 0.5 to 3 μm, and most preferably 1 to 2 μm. The D50 particle size distribution is measured using a Malvern Mastersizer in accordance with ISO Standard 13320:2009.

[0132] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may further comprise an additive or a combination of additives. Suitable additives are well known to those skilled in the art. Examples of suitable additives include, but are not limited to, the following: polymers; light or energy absorbers; UV absorbers; surfactants; wetting agents; drying accelerators; colorants such as pigments; colorants; fluorescent agents; plasticizers; optical brighteners; oxidizing or reducing agents; stabilizers; light stabilizers such as hindered amines; rheology modifiers such as thickeners or diluents; humectants; adhesion promoters; acid or base scavengers; retarders; defoamers; antifoaming agents; and combinations thereof. Preferably, the first composition utilised in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention comprises 0.1 to 25 wt%, such as 0.1 to 20 wt%, such as 0.1 to 15 wt%, such as 0.1 to 12 wt%, or even 0.1 to 10 wt% of an additive or combination of additives.

[0133] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention preferably does not contain any pigments or dyes.

[0134] The first composition may incorporate the protein in a dry powder form, for example, a dehydrated form such as lyophilized or spray dried.

[0135] The inventors have further identified that in the context of the present invention, the first composition can act as a barrier layer, for example, against gas migration, which is particularly true when the plastic substrate is a multi-layer plastic structure.

[0136] The first composition utilized in the first, second, third, fourth, fifth, eighth, tenth, and twelfth aspects of the present invention may be formed by any suitable method known to those skilled in the art. The near infrared absorber, if utilized, is preferably milled using a mechanical bead mill, such as an Eiger Torrance M50 mechanical bead mill, before being added to the other components of the composition.

[0137] With respect to the second through thirteenth aspects of the present invention, it is understood that when a second composition or a composition containing a leuco dye coated on a first composition on a plastic substrate is irradiated, the coloring compound forms a color. Additionally, when the second composition, and therefore the underlying first composition, is irradiated, the protein also forms a color. It is understood that the protein is denatured upon irradiation, undergoing a conformational change, i.e., a transition from its non-denatured state to a denatured state, at localized locations irradiated using a laser. At these localized locations, the protein forms a white color. This serves to enhance the color formed by the coloring compound of the second composition upon irradiation.

[0138] With respect to the first through fifth and seventh through thirteenth aspects of the present invention, the plastic substrate preferably defines a volume. The volume is usable to hold or preserve contents, such as liquids or solids. The contents can be medicines, food and beverages, or non-consumable personal care and household products. The plastic substrate can be three-dimensional. The plastic substrate can have exterior wall(s), such as an outer wall, that defines an interior volume usable to hold contents. It is understood that the exterior wall(s) can define two or more interior volumes (separate or connected) for the plastic substrate usable to hold contents.

[0139] The first composition, the second composition, and / or the composition comprising the leuco dye may be applied to or incorporated into a plastic substrate. Preferably, the first composition, the second composition, and / or the composition comprising the leuco dye is applied to a plastic substrate.

[0140] The inventors have advantageously discovered that the first composition, second composition, and / or composition comprising leuco dye described herein can be directly applied to or incorporated into plastic substrates.This finds particular use when the plastic substrate clearly defines a volume, such as plastic packaging, for example, plastic containers, plastic pouches, plastic bottles, plastic blister packs, or plastic clamshell packs.Directly irradiate the plastic substrate to create a mark or image on the substrate, and then remove the radiation-reactive, preferably laser-reactive, composition from the plastic substrate, and the resulting mark or image can be removed without contaminating plastic materials or waste streams, thereby avoiding the need for separate label components.This is advantageous because, usually, when such plastic substrates and labels are disposed of, the disposal processes for the plastic substrates and labels are different and incompatible. For separate articles (substrate and label), either two different recycling processes are required, one of the articles cannot be recycled, or in some cases, the two articles become bonded and cannot or are difficult to separate after application of the label to the substrate, resulting in a suitable recycling process not being or being difficult to achieve. From a sustainability perspective, this is far from ideal.

[0141] Preferably, the first composition, the second composition and / or the composition comprising the leuco dye are applied directly to the plastic substrate.

[0142] Therefore, with regard to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate is preferably other than a label.

[0143] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate is preferably plastic packaging. Plastic packaging includes plastic lids and plastic containers, such as plastic food and / or beverage containers, pharmaceutical containers, or non-consumable personal care and household containers. Suitable examples of plastic containers include plastic boxes, plastic pouches, plastic bottles, such as plastic beverage bottles, plastic blister packaging, typically used in the pharmaceutical and tobacco or vaping industries, and clamshell packaging, typically used in the food industry.

[0144] It is understood that a plastic substrate includes a plastic substrate as described herein having additional plastic components associated therewith, for example, a plastic bottle may have a plastic lid associated therewith. Plastic substrates also include a plastic substrate as described herein having additional non-plastic components associated therewith, for example, a metal, aluminum foil, or paper sealing layer (lidding stop) in a blister pack. Thus, a plastic substrate of the present invention includes any plastic substrate as described herein, including any associated closure, pump, cap, nozzle, handle, lid, or cover.

[0145] Plastic substrates can be used to store, transport and deliver products such as pharmaceuticals, food and beverages, and non-consumable personal care and household products.

[0146] In the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate is preferably a plastic container. More preferably, the plastic substrate is a plastic box, a plastic pouch, a plastic bottle, a plastic blister pack, or a plastic clamshell pack. More preferably, the plastic substrate is a plastic box, a plastic pouch, or a plastic bottle. Most preferably, the plastic substrate is a plastic bottle.

[0147] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate may be formed from any suitable plastic material.

[0148] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate is preferably formed from polyethylene terephthalate (PET), high-density polyethylene (HDPE), polypropylene (PP), including oriented polypropylene (OPP) and biaxially oriented polypropylene (BOPP), recycled polyethylene terephthalate (r-PET), low-density polyethylene (LDPE), or a combination thereof. These plastic materials are recyclable, and as a result, it will be understood by those skilled in the art that the plastic substrate can be formed from any suitable recyclable plastic material.

[0149] In the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate is more preferably formed from polyethylene terephthalate (PET) or recycled polyethylene terephthalate (r-PET), and most preferably formed from polyethylene terephthalate (PET).

[0150] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate may be in the form of a polymer film.

[0151] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate may be metallized. By metallized, it is meant that the plastic substrate is coated with a thin layer of metal, e.g., aluminum. In these cases, the plastic substrate may be a polymer film, such that the plastic substrate is a metallized polymer film. Such a film may be used, for example, as a barrier layer in a multilayer plastic structure.

[0152] In the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate may be transparent, translucent, or opaque. The plastic substrate may be colored, white, or colorless.

[0153] With respect to the first to fifth and seventh to thirteenth aspects of the present invention, the plastic substrate may be a multi-layer plastic structure, which may be known in the art as a laminate structure.

[0154] Such a multilayer plastic structure can include two or more layers of any suitable plastic material, including those described above with respect to the plastic substrate. The multilayer plastic structure can include at least one layer of a first composition described herein and at least one layer of a second composition or a composition comprising a leuco dye disposed between two plastic material layers. For example, the multilayer plastic structure can include one layer of a second composition or a composition comprising a leuco dye disposed between two layers of the first composition. The at least one layer of the first composition and the at least one layer of the second composition or a composition comprising a leuco dye can cover the entire plastic material layer or at least a portion of the plastic material layer. The at least one layer of the first composition and the at least one layer of the second composition or a composition comprising a leuco dye described herein can also be applied to at least a portion of the outer surface of the multilayer plastic structure. The multilayer plastic structure can be considered to include multiple distinct layers.

[0155] With respect to the multilayer structures described herein, preferably, each of the two or more layers of plastic material is associated with one or both sides of at least one layer of the first composition described herein. By "associated," we mean that at least one layer of the first composition is in direct contact with or positioned opposite each plastic material layer, thereby facilitating removal of the second composition or the composition containing the leuco dye from that material layer. It is understood that this at least one layer may be on one or both sides of the plastic layer, depending on its location within the multilayer plastic structure. For example, if a plastic layer is an outer layer of a multilayer plastic structure, it is understood that this plastic layer is typically associated with at least one layer of the first composition on its inner surface, i.e., within the multilayer plastic structure. Similarly, if a plastic layer is an inner layer of a multilayer plastic structure, i.e., within the multilayer plastic structure, the plastic layer typically has at least one layer of the first composition located on each side thereof, i.e., has at least one layer of the first composition applied to each side thereof.

[0156] With respect to multi-layer plastic structures, it is understood that at least one of the two or more layers of plastic material may be transparent or translucent so that marks or images can be seen therethrough.

[0157] Typically, in the context of the present invention, the multi-layer plastic structure corresponds to a laminated film package. Typically, the multi-layer plastic structure is a plastic pouch, a plastic box, or a plastic bottle, preferably a plastic pouch. The two or more layers of plastic material are preferably in the form of a polymer film.

[0158] For the multi-layer plastic structures described herein, each layer of plastic material is preferably in contact with a layer of the first composition described herein on one or both sides thereof. For example, an outer layer of a plastic material (a layer on the outside of the multi-layer plastic structure) can be in contact with at least one layer of the first composition within the multi-layer plastic structure, and any inner layer of a plastic material (inside the multi-layer plastic structure) can be in contact with at least one layer of the first composition on each side of the plastic material.

[0159] With respect to the multilayer plastic structures described herein, the two or more layers of plastic material may be the same or different. This may be with respect to material type, color, thickness, and / or transparency, etc. One of the two or more layers of plastic material may be metallized, for example, to act as a barrier layer. One or more of the two or more layers of plastic material may be a "heat-sealed" plastic material. Such materials are typically formed through a process, such as melting the plastic material itself.

[0160] With respect to multilayer plastic structures, the multilayer plastic structure preferably includes two or three layers of plastic material. When three layers of plastic material are used, it is understood that at least one layer of both the first composition and the second composition described herein may be disposed between two plastic material layers, or between the first and second plastic material layers, or similarly between the second and third plastic material layers. For example, one layer of the second composition between two first compositions may be disposed between two plastic material layers, or one layer of the second composition between two first compositions may be disposed between the first and second plastic material layers, or similarly between the second and third plastic material layers. When at least one layer of both the first and second compositions described herein is disposed between two plastic material layers (e.g., between the first and second layers, or between the second and third layers, respectively), a layer of the first composition may also be disposed between two other layers (e.g., between the second and third layers, or between the first and second layers, respectively). For example, between two first compositions, one layer of the second composition may be disposed between the first and second plastic material layers, and one layer of the first composition may be disposed between the second and third plastic material layers. It is understood that this depends on the structure of the multilayer plastic structure with respect to the different plastic materials in terms of the type of material and the layer peeling required for the recycling process.

[0161] For multi-layer plastic structures, at least two of the two or more layers of plastic material are preferably formed from different types of plastic material. For example, one plastic material can be PET and the other can be OPP. As described above, the present invention advantageously allows the different types of plastic in such structures to be separated and effectively recycled without contamination from the second composition. When delamination of the multi-layer plastic structure occurs in an alkaline aqueous solution, the densities of the different plastic materials can aid in the separation.

[0162] The two or more layers of plastic material of the multi-layer plastic structures described herein may have a thickness of 8 to 100 μm.

[0163] The multilayer plastic structures described herein typically have an overall thickness of 500 μm or less, such as 200 μm or less.

[0164] For the multilayer plastic structure described herein, one or more additional layers may also be present. The one or more additional layers may have a thickness of 100 μm or less. Suitable additional layers may be selected from, but are not limited to, a thermal insulation layer; a protective layer; an adhesion-promoting layer; an adhesive layer; a barrier layer comprising a metal foil or a coated plastic material; a quenching layer; and a hindered amine light stabilizer; or a combination thereof. It is understood that the arrangement of the one or more additional layers in the sequence of the individual layers of the multilayer plastic structure may vary depending on the type of the one or more additional layers utilized and their function in the multilayer plastic structure. Preferably, the one or more layers are adhesive layers, barrier layers, adhesion-promoting layers, or protective layers.

[0165] For the multilayer plastic structures described herein, at least one layer of the first composition and at least one layer of the second composition may be applied as a single layer or multiple layers, i.e., applied one or more times. This also applies to one or more additional layers. At least one layer of the first composition and at least one layer of the second composition and at least one additional layer may be applied up to the coating weights detailed herein for the first composition and the second composition, respectively.

[0166] With respect to the multilayer plastic structure described herein, the multilayer plastic structure is preferably formed in the following order: a layer of plastic material; a layer of the first composition described herein; a layer of the second composition described herein; one or more additional layers; a layer of the first composition described herein; and a layer of plastic material. As explained above, the two layers of plastic material may be the same or different. For example, one may be PET and the other may be OPP. The two layers of plastic material are preferably formed from different plastic materials. The layers of plastic material are preferably in the form of polymer films.

[0167] With respect to the multilayer plastic structure described herein, it is more preferred that the multilayer plastic structure is formed in the following order: a layer of plastic material; a layer of the first composition described herein; a layer of the second composition described herein; an adhesive layer; a layer of the first composition described herein; and a layer of plastic material. As explained above, the two layers of plastic material may be the same or different. For example, one may be PET and the other may be OPP. Preferably, the two layers of plastic material are formed from different plastic materials. Preferably, the layer of plastic material is in the form of a polymer film.

[0168] With respect to the multi-layer plastic structures described herein, it is understood that the mark or image is formed using the second composition, and thus the mark or image is formed "inside" or "integrated within" the multi-layer plastic structure. In the context of the present invention, when the term "mark or image formed therein" is used, this also encompasses a mark or image formed "inside" or "integrated within" the multi-layer plastic structure. The multi-layer plastic structure displays the mark or image.

[0169] If the plastic substrate is a multi-layer plastic structure, exposing the plastic substrate to an alkaline aqueous solution will cause delamination of the multi-layer plastic structure, as well as deinking the second composition and therefore the mark or image.

[0170] As used herein, the terms "exfoliate," "exfoliating," "peeling," or other similar terms, with respect to multi-layer plastic structures, refer to the separation of layers of plastic material of the multi-layer plastic structure from one another.

[0171] As used herein, the terms "deinking," "deinking," "deinked," or other similar terms specifically refer to the removal of a mark or image from a layer of plastic material in a multilayer plastic structure by separating the second composition that forms the mark or image from each layer of plastic material in the multilayer plastic structure. "Stripping" and "deinking" of a multilayer plastic structure typically occur simultaneously upon exposure to an aqueous alkaline solution in the processes described herein. Complete "deinking" occurs when each of two or more layers of plastic material in a multilayer plastic structure is bound to at least one layer of the first composition described herein on one or both sides.

[0172] As used herein, the terms "deink," "deinking," "deinked," or other similar terms also refer to the removal of a mark or image from any plastic substrate, i.e., a plastic substrate as defined herein, other than a multilayer plastic structure, by separation of the second composition or composition comprising the leuco dye from the plastic substrate upon exposure to an alkaline aqueous solution as described herein.

[0173] When the second composition used in the second, third, fourth, fifth, tenth, or twelfth aspects of the present invention, or the leuco dye-containing compositions of the sixth, seventh, eighth, ninth, eleventh, and thirteenth aspects of the present invention, is formulated and applied to a plastic substrate, no premature color formation occurs. The formation of a mark or image is achieved solely through specific irradiation treatment using a laser at the localized location of the second composition or the leuco dye-containing composition. Therefore, prior to irradiation treatment, the plastic substrate does not display a mark or image formed by the second composition or the leuco dye-containing composition.

[0174] The coloring compound facilitates the formation of marks or images on the plastic substrate.

[0175] As used herein, the term "color" and similar terms refer to all colors and hues in the visible light color spectrum, i.e., red, orange, yellow, blue, green, and blue-violet, as well as black, brown, turquoise, purple, pink, cyan, and magenta, and mixtures thereof. Both primary and secondary colors are included; that is, those skilled in the art will understand that the color formed by the leuco dye upon exposure of the composition to radiation can be a primary color or a secondary color. In the context of the present invention, the term can also be used to describe different shades of each color in the visible light color spectrum, in addition to magenta, cyan, pink, purple, turquoise, brown, and black.

[0176] It is understood that the color of the mark or image formed will depend on the selection of the coloring compound. Typically, if the coloring compound is selected to be an oxyanion of a polyvalent metal or an oxyanion or hydrate thereof, the color formed may be black. Typically, if a leuco dye is selected, the color will be other than black.

[0177] The marks or images formed are clearly visible to the human eye and / or machine readable. Preferably, the marks or images formed are recognizable and identifiable.

[0178] By "recognizable" and "distinguishable" as used herein in connection with a mark or image, it is meant that the image is clearly visible to the human eye and / or machine readable. The mark or image contrasts with the color background of the second composition or compositions and / or plastic substrate, i.e., the mark or image is readily distinguishable from their background. The mark or image is thus a "contrasting" mark or image.

[0179] The marks or images formed can be evaluated by measuring absolute density values. This can be: absolute optical density black (ODB) values, typically used to evaluate marks or images that are black in color or tone or shade; absolute optical density magenta (ODM) values, typically used to evaluate marks or images that are red in color or tone or shade; absolute optical density cyan (ODC) values, typically used to evaluate marks or images that are blue in color or tone or shade; or absolute optical density yellow (ODY) values, typically used to evaluate marks or images that are yellow in color or tone or shade. In the context of ODB, ODM, ODC, and ODY values, the higher the value, the darker the respective color formed. Absolute ODB, ODM, ODC and ODY values ​​quantify optical density from low to high on a scale of black, magenta, cyan or yellow, respectively, and measurements of ODB, ODM, ODC and ODY can be made using a standard densitometer and an X-Rite eXact or SpectroEye or TechKon SpectroDens spectrophotometer. A recognizable and identifiable mark or image preferably has an absolute ODB, ODM, ODC or ODY value of 0.7 or greater, such as 0.8 or greater, or 0.9 or greater, such as 1.0 or greater.

[0180] The mark or image may also be evaluated over time by measuring absolute density values ​​over time, as described above. A mark or image is said to be retained if an absolute ODB, ODM, ODC, or ODY value of 0.7 or greater, such as 1.0 or greater, is maintained for a specified period of time. The mark or image may be retained for 1 week to 6 months, e.g., 1 week to 5 months, or 1 week to 3 months, e.g., 1 week to 2 months, or 1 week to 6 weeks, or 1 week to 5 weeks, e.g., 10 days to 6 months, or 10 days to 5 months, or 10 days to 3 months, e.g., 10 days to 2 months, or 10 days to 6 weeks, or 10 days to 5 weeks.

[0181] Consideration of excessive coloration in the "background" of a second composition or composition containing a leuco dye, in which a mark or image is formed, i.e., the portion of the composition in which no mark or image is formed, can be evaluated by measuring the ΔE value. This value is expressed as L * a * b * The difference in color is measured to determine whether the second composition or composition containing the coloring compound has colored other than the desired formation of a mark or image. It is understood that this measurement can also be used to determine whether premature color formation occurs with the second composition or composition containing the coloring compound before irradiation to form a mark or image. A sample of the plastic substrate to which the first composition has been applied and the second composition or composition containing the coloring compound has been applied, but without an image (i.e., before irradiation), or a sample of the plastic substrate to which the first composition has been applied and the second composition or composition containing the coloring compound has been applied and imaged by irradiation, is compared to an uncoated sample of the plastic substrate. ΔE can be measured with an X-rite eXact spectrophotometer using standard mathematical formulas defined herein. ΔE measurements can be performed on a white background. A low ΔE measurement is preferred and indicates little quantitative color difference between the two samples being compared, so that they are qualitatively comparable and appear visually identical, i.e., no premature coloration occurs or the background of the composition is not noticeably colored, preventing the formation of a recognizable and identifiable mark or image. The ΔE measurement may be less than 5, such as less than 3.5, such as less than 3, or less than 2.

[0182] With respect to the second to fifth, eighth, and tenth to thirteenth aspects of the present invention, the plastic substrate can be irradiated to selectively promote localized color formation of the second composition or the leuco dye-containing composition to form a desired mark or image, i.e., variable information. The irradiation treatment is controlled and specific. A human- and / or machine-readable mark or image is formed, typically in only a portion or region of the plastic substrate.

[0183] It is understood that the color of the mark or image is selected to contrast with the color of the background of the second composition or composition containing the leuco dye and / or the color of the plastic substrate, so that the mark or image is clearly visible and easily distinguishable from the background of the second composition or composition containing the leuco dye, i.e., distinguishable from any substrate visible through the second composition or portion(s) of the composition that have not been exposed to radiation, and similarly, through the portion(s) of the second composition or composition containing the leuco dye that have not been exposed to radiation.

[0184] The term "image" or "mark" incorporates, but is not limited to: marks such as logos, phrases and words, graphics, figures, photographs, symbols, codes such as linear barcodes, 2D data matrices, QR codes, Digimark codes, and phrases such as those based on alphanumeric characters and symbols. In the context of the present invention, it is understood that it is the coloring compound that facilitates the formation of a mark or image on a plastic substrate. The formed mark or image is human and / or machine readable and can be used for coding and marking, tagging, tracking and tracing, and later customization or personalization purposes. The formed mark or image is typically a mark or image used to display variable information.

[0185] In the context of the present invention, the irradiation treatment is carried out after the second composition or the composition containing the coloring compound is applied to the plastic substrate. This may be carried out immediately after application or at a later time, such as after storage or transportation. If the plastic substrate is a multilayer plastic structure, it is understood that the irradiation treatment is carried out after the formation of the multilayer plastic structure, either immediately after formation or at a later time, such as after storage or transportation.

[0186] It is understood that the selected irradiation is required for the colored compound to form a mark or image.

[0187] As used herein, "radiation" and like terms refer to energy in the form of waves or particles, particularly electromagnetic radiation such as ultraviolet (UV), visible, near-infrared (NIR) and infrared (IR) particle radiation, e.g., alpha (α), beta (β), neutron radiation, and plasma. Wavelength ranges in different regions of the electromagnetic spectrum are known to those skilled in the art.

[0188] With respect to the second to fifth, eighth, and tenth to thirteenth aspects of the present invention, the irradiation may be selected from ultraviolet (UV) irradiation having a wavelength of 10 to 400 nm, infrared (IR) irradiation having a wavelength of 700 nm to 1 mm, including near-infrared (NIR) irradiation having a wavelength of 700 to 1600 nm, such as 950 to 1100 nm. The irradiation is preferably selected from infrared (IR) irradiation having a wavelength of 9000 to 12000 nm, such as 9300, 9600, 10200, or 10600 nm, infrared irradiation having a wavelength of 700 nm to 1 mm, and near-infrared (NIR) irradiation having a wavelength of 700 to 1600 nm. More preferably, the radiation is selected from infrared (IR) radiation having a wavelength of 9300, 9600, 10200, or 10600 nm, infrared radiation having a wavelength of 700 nm to 1 mm, and near-infrared (NIR) radiation having a wavelength of 700 to 1600 nm. Most preferably, the radiation is infrared (IR) radiation having a wavelength of 10600 nm and near-infrared (NIR) radiation having a wavelength of 950 to 1100 nm.

[0189] Preferably, infrared radiation having a wavelength of 9000 to 12000 nm, such as 9300, 9600, 10200 or 10600 nm, is applied using a CO2 laser.

[0190] In the context of the present invention, the term "NIR or IR radiation" refers to radiation selected from infrared (IR) radiation having a wavelength of 9000 to 12000 nm, such as 9300, 9600, 10200 or 10600 nm, infrared (IR) radiation having a wavelength of 700 nm to 1 mm, and near-infrared (NIR) radiation having a wavelength of 700 to 1600 nm. Preferably, the radiation is infrared (IR) radiation having a wavelength of 10600 nm and near-infrared (NIR) radiation having a wavelength of 950 to 1100 nm.

[0191] With respect to the second to fifth, eighth and tenth to thirteenth aspects of the invention, irradiation may be applied using a UV, CO2 or fiber laser.

[0192] By the term "laser-responsive" composition, as used herein, is meant a composition that forms color upon irradiation from a laser. It will be understood by those skilled in the art that irradiation can be applied to localized locations in an area or portion of a plastic substrate to selectively promote the formation of color, and thus the formation of a mark or image, at those localized locations. These localized locations may overlap one another.

[0193] Those skilled in the art will understand that irradiation is carried out for a suitable time required to promote the formation of marks or images.Typically, the time required to provide sufficient irradiation depends on the means and processing method used for irradiation.For example, in one embodiment, irradiation can be carried out for less than 30 seconds, for example, less than 20 seconds or 15 seconds, or even less than 10 or 5 seconds.

[0194] Irradiation may be performed by any suitable means. Preferably, irradiation is applied to the plastic substrate, i.e., the second composition or the composition containing the leuco dye, using a non-contact means or source. By "non-contact" means, irradiation is meant to be performed by a means or source that does not come into contact with the plastic substrate and the second composition or the composition containing the leuco dye. Suitable means include laser excitation through irradiation with a laser source(s). Irradiation is preferably performed using a laser source(s). As used herein, the term "laser source(s)" and similar terms refer to any suitable commercially available or non-commercially available laser source(s). Suitable examples include, but are not limited to, fiber lasers, fiber-coupled semiconductor laser arrays, CO2 lasers, semiconductor laser arrays, or direct semiconductor lasers to provide irradiation, including near-infrared or mid-infrared irradiation.

[0195] When applied using laser source(s), the applied radiation dose depends on the duration of the irradiation process, the power (wattage) of the means used for the irradiation process, and therefore the fluence (amount of energy delivered per unit area) delivered by the laser source(s), e.g., J / cm 2It will be understood that the density / opacity can be controlled by varying the fluence. Those skilled in the art will understand that this can affect the density / opacity, i.e., the "effective value," of the mark or image formed. For example, when a laser source(s) is used to perform the irradiation process, the fluence (the amount of energy delivered per unit area) can affect the density / opacity, i.e., the "effective value," of the mark or image formed. In the context of the present invention, the fluence depends on the power (wattage) of the means used to perform the irradiation process and the time spent irradiating a specific local location on a part of the plastic product, which can be controlled by the scanning speed of the laser or the speed of the moving stage. These two variables can be changed to change the fluence. When the fluence is low (e.g., low power and / or short irradiation time), the mark or image formed has low density / low opacity, and when the fluence is high (e.g., high power and / or long irradiation time), the mark or image formed has high density / high opacity. In the context of the present invention, the fluence value is between 0.01 and 100 J / cm. 2 , 0.1~50J / cm 2 etc., and 0.5 to 25 J / cm 2 The range may be:

[0196] The leuco dye-containing composition, first composition, and second composition defined herein, in relation to the first to thirteenth aspects of the present invention, can be applied to the plastic substrate, or, if the plastic substrate is a multi-layer plastic structure, to the plastic material component(s), i.e., to the plastic material layer, by any suitable process. Suitable application methods include, but are not limited to, the following: spray application, flexographic printing, gravure printing, screen printing, and pad printing, preferably flexographic printing, gravure printing, screen printing, and pad printing. Flexographic printing conforms to ISO 2834-2.

[0197] With respect to the first to thirteenth aspects of the present invention, the compositions comprising the leuco dye, the first composition and the second composition as defined herein may be applied directly to the plastic substrate or, if the plastic substrate is a multi-layer plastic structure, preferably directly to a component(s) of the plastic material, i.e., a plastic material layer.

[0198] As used herein, "direct application" refers to applying the first composition, the second composition, or the composition containing a leuco dye to the plastic substrate itself, rather than to any other substrate bonded or connected to the plastic substrate. When the plastic substrate is a multilayer substrate structure, "direct application" refers to applying the first composition and the second composition or the composition containing a leuco dye to a plastic material layer of the multilayer plastic structure, and disposing the composition between two layers of plastic material in the multilayer plastic structure, i.e., within the multilayer substrate structure, without any other substrate bonded or connected to the multilayer plastic structure. For example, when the plastic substrate is a plastic substrate with a clearly defined volume, this refers to applying the first composition, the second composition, or the composition to the plastic substrate itself, rather than to a label or other substrate bonded or connected to the plastic substrate.

[0199] The first composition, second composition, or leuco dye-containing composition of the first to thirteenth aspects of the present invention can be applied to at least a portion of a plastic substrate, or, if the plastic substrate is a multilayer plastic structure, to at least a portion of a component(s) of the plastic material, i.e., a plastic material layer. They can be applied to two or more locations on the plastic substrate or component(s) of the plastic material (e.g., a plastic material layer of a multilayer plastic structure). When the first composition, second composition, or leuco dye-containing composition is applied to two or more locations on the plastic substrate or component(s) of the plastic material (e.g., a plastic material layer of a multilayer plastic structure), it is understood that the coloring compound of the second composition or leuco dye-containing composition can be different in each location, thereby providing different colored marks or images on the same plastic substrate.

[0200] In some cases, the first composition, the second composition or the composition comprising a leuco dye according to the first to thirteenth aspects of the present invention may be applied to all of the exterior surfaces of a plastic substrate.

[0201] An overvarnish may be applied over the second composition or the composition containing the coloring compound on a plastic substrate to improve the abrasion resistance of the first composition, the second composition, or the composition containing the leuco dye. Suitable overvarnishes include, but are not limited to, those based on styrene-acrylic, polyvinyl butyral, nitrocellulose, polyurethane, acrylic, polyvinyl chloride, polyvinyl acetate, polyamide, alkyd, polyester, and epoxy-based resins.

[0202] The first composition, second composition, or leuco dye-containing composition of the first through thirteenth aspects of the present invention can be applied to a plastic substrate or plastic material component(s) (e.g., a plastic material layer of a multi-layer plastic structure) to any suitable dry coating weight (gsm), depending on both the substrate to which the composition is applied and the application method. Those skilled in the art will understand that the dry coating weight (gsm) of the composition on the substrate will affect the density of the mark or image formed.

[0203] With respect to the first to thirteenth aspects of the present invention, the first composition may be applied to a plastic substrate or plastic material component(s) (e.g. a plastic material layer of a multi-layer plastic structure) at a dry coating weight of 0.1 to 10 gsm (grams per square metre), for example 0.2 to 5 gsm, or 0.2 to 2 gsm, or 0.5 to 2 gsm, such as 0.5 to 1.5 gsm.

[0204] With respect to the first to thirteenth aspects of the present invention, the first composition may be applied to the plastic substrate or plastic material component(s) (e.g. a plastic material layer of a multi-layer plastic structure) at a wet coating weight of 0.2 to 20 gsm, for example 0.4 to 10 gsm, or 0.4 to 4 gsm, or 1 to 4 gsm, such as 1 to 3 gsm.

[0205] The second composition or compositions of the second to thirteenth aspects of the present invention may be applied to a plastic substrate or plastic material component(s) (e.g. a plastic material layer of a multi-layer plastic structure) at a dry coating weight of from 0.5 to 15 gsm (grams per square metre), for example from 0.5 to 10 gsm, or such as from 1 to 10 gsm, most preferably from 1 to 8 gsm, or such as from 1 to 6 gsm, 1 to 4 gsm.

[0206] The dry coating weight can be measured by any suitable method. Suitable measurement methods are well known to those skilled in the art. In the context of the present invention, the dry coating weight is the weight of the coating applied to the same unit area of ​​substrate (e.g., 100 cm 2) is measured by weighing an item with and without the composition applied and determining the difference between the two weights.

[0207] The second composition or the composition comprising a leuco dye according to the second to thirteenth aspects of the present invention may be applied to a plastic substrate or plastic material component(s) (e.g. a plastic material layer of a multi-layer plastic structure) at a wet coating weight of from 1 to 30 gsm, or from 1 to 20 gsm, or from 2 to 20 gsm, such as from 2 to 16 gsm, or from 2 to 12 gsm, or from 2 to 8 gsm.

[0208] The wet coating weight can be measured by any suitable method. Suitable measurement methods are well known to those skilled in the art. In the context of the present invention, the wet coating weight is

[0209]

number

[0210] Wet coating weight is understood to be the coating weight of the second composition or the composition comprising a leuco dye applied to a plastic substrate or component(s) of the plastic material (e.g., a plastic material layer of a multi-layer plastic structure). After application, the second composition or the composition comprising a leuco dye is dried to remove all or part of the water or organic solvent.

[0211] The first composition, the second composition or the composition comprising a leuco dye according to any of the first to thirteenth aspects of the present invention may each be applied to a plastic substrate or component(s) of a plastic material (e.g. a plastic material layer of a multi-layer plastic structure) as a single layer or multiple layers, i.e., once or multiple times.

[0212] All features contained herein may be combined with any of the above aspects in any combination.

[0213] All references herein to specific chemical compounds should be interpreted as encompassing the compounds themselves, and, where appropriate, their derivatives, hydrates, solvates, complexes, isomers and tautomers.

[0214] For a better understanding of the present invention and to show how embodiments thereof may be put into practice, reference will now be made, by way of example, to the following experimental data. [Example]

[0215] [Example 1] The second composition utilized in the second, third, fourth, fifth, tenth, and twelfth aspects of the present invention, or the composition including the leuco dye utilized in the sixth, seventh, eighth, ninth, eleventh, or thirteenth aspects of the present invention, was prepared according to Table 1. All amounts are in weight percentage (wt%).

[0216] [Table 1]

[0217] [Example 2] A second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the present invention was prepared according to Table 2. All amounts are in weight percentage (wt%).

[0218] [Table 2]

[0219] [Example 3] A first composition utilized in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention was prepared according to Table 3. All amounts are in weight percentage (wt%).

[0220] [Table 3]

[0221] [Example 4] A first composition utilized in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention was prepared according to Table 4. All amounts are in weight percentage (wt%).

[0222] [Table 4]

[0223] [Example 5] According to EPBP (European PET Bottle Platform) Quick Test QT 507 (March 2017): A layer of the first composition prepared according to Example 3 was applied to a portion of the PET substrate at 1 gsm using a RK K control coater. A layer of the second composition prepared according to Example 1 or a composition containing a leuco dye was applied over the first composition at 2 gsm using an RK K control coater. The second composition was subjected to infrared irradiation using a CO2 laser to form a QR code (mark or image) on the plastic substrate. PET substrate, 1cm 2 The mixture was cut into thin slices. The PET flakes were placed in a 2 wt.% aqueous solution of sodium hydroxide at 80°C and 500 rpm for 15 minutes. The supernatant was saved. This was repeated two more times. The PET flakes were rinsed to remove the aqueous sodium hydroxide solution. The PET flakes were dried in an oven at 105°C. PET flakes L * , a * and b * Values ​​were measured on an X-rite eXact spectrophotometer (average of 10 measurements taken).

[0224] [Example 6] According to EPBP (European PET Bottle Platform) Quick Test QT 507 (March 2017): A layer of the first composition prepared according to Example 3 was applied to a portion of the PET substrate at 1 gsm using a RK K control coater. A layer of a second composition prepared according to Example 2 was applied over the first composition at 2 gsm using an RK K control coater. The second composition was subjected to infrared irradiation using a CO2 laser to form a QR code (mark or image) on the plastic substrate. PET substrate, 1cm 2 The mixture was cut into thin slices. The PET flakes were placed in a 2 wt.% aqueous solution of sodium hydroxide at 80°C and 500 rpm for 15 minutes. The supernatant was saved. This was repeated two more times. The PET flakes were rinsed to remove the aqueous sodium hydroxide solution. The PET flakes were dried in an oven at 105°C. PET flakes L * , a * and b * Values ​​were measured with an X-rite eXact spectrophotometer (average of 10 measurements taken).

[0225] [Example 7] According to EPBP (European PET Bottle Platform) Quick Test QT 507 (March 2017): A layer of the first composition prepared according to Example 4 was applied to a portion of the PET substrate at 1 gsm using a RK K Control Coater. A layer of a second composition prepared according to Example 2 was applied over the first composition at 2 gsm using an RK K control coater. The second composition was subjected to infrared irradiation using a CO2 laser to form a QR code (mark or image) on the plastic substrate. PET substrate, 1cm 2 The mixture was cut into thin slices. The PET flakes were placed in a 2 wt.% aqueous solution of sodium hydroxide at 80°C and 500 rpm for 15 minutes. The supernatant was saved. This was repeated two more times. The PET flakes were rinsed to remove the aqueous sodium hydroxide solution. The PET flakes were dried in an oven at 105°C. PET flakes L * , a * and b * Values ​​were measured with an X-rite eXact spectrophotometer (average of 10 measurements taken).

[0226] result The L of the PET flakes obtained in Examples 5, 6 and 7 * , a * and b * The values ​​were compared to an uncoated PET sample strip (control) and the results are shown in Table 5 below. In the CIELAB color system (CIELAB color space) - a color space defined by the International Commission on Illumination (CIE) in 1976 - L * represents the lightness, and a * represents the red / green value, and b * represents the yellow / blue value. The ΔE measurements were then calculated using a white background, and the results are shown in Table 5 below. ΔE is a standard mathematical calculation that allows for the quantification of the visual perception of the difference between two colors (here, the difference between the control and the PET flakes obtained from Examples 5, 6, and 7). ΔE is calculated using the following formula: L = L * , a=a * and b=b * ) is calculated using

[0227]

number

[0228] [Table 5]

[0229] [Example 8] A second composition utilized in the second, third, fourth, fifth, tenth and twelfth aspects of the present invention was prepared according to Table 6. All amounts are in weight percentage (wt%).

[0230] [Table 6]

[0231] [Example 9] A first composition utilized in the first, second, third, fourth, fifth, eighth, tenth and twelfth aspects of the present invention was prepared according to Table 7. All amounts are in weight percentage (wt%).

[0232] [Table 7]

[0233] [Example 10] A multi-layer plastic structure (laminate structure) was constructed having the following layers: 1.PET polymer film (23μm thick); 2. A first composition prepared according to Example 9; 3. A second composition prepared according to Example 8; 4. Adhesive (commercially known as Novocote SF716A+CA336 Adhesive) 5. A first composition prepared according to Example 9; 6. White OPP polymer film (40 μm thick).

[0234] [Comparative Example 10a] A multi-layer plastic structure not in accordance with the present invention was constructed having the following layers: 1.PET polymer film (23μm thick); 2. A second composition prepared according to Example 8; 3. Adhesive (commercially known as Novocote SF716A+CA336 adhesive); 4. White OPP polymer film (40 μm thick).

[0235] [Example 11] The first composition prepared according to Example 9 and the second composition prepared according to Example 8 were used to form the multi-layer plastic structure of Example 10. The second composition prepared according to Example 8 was used to form the multi-layer plastic structure of Comparative Example 10a.

[0236] For the multi-layer plastic structure of Example 10, a layer of the first composition prepared according to Example 9 was applied to a PET polymer film and an OPP polymer film at a coating weight of 1 gsm using an RK K control coater. A layer of the second composition prepared according to Example 8 was applied over the first composition on the PET polymer film at a coating weight of 2 gsm using an RK K control coater. An adhesive layer (commercially known as Novocote SF716A+CA336 adhesive) was applied over the second composition on the PET polymer film at a coating weight of 2 gsm using an RK K control coater. These layers were laminated together using a Cheminstruments LL-100 laboratory laminator to form a laminated structure according to Example 10. For the multilayer plastic structure of Comparative Example 10a, a layer of the second composition prepared according to Example 8 was applied to a PET polymer film at a coating weight of 2 gsm using an RK K Control Coater. An adhesive layer (commercially known as Novocote SF716A+CA336 adhesive) was applied over the second composition on the PET polymer film at a coating weight of 2 gsm using an RK K control coater. The layers were laminated together using a Cheminstruments LL-100 laboratory laminator to form a laminated structure according to Comparative Example 10a. Both multi-layer plastic structures, and therefore the second composition, were irradiated with infrared light using a CO2 laser, resulting in a mark or image being displayed by the multi-layer plastic structure. Each multilayer plastic structure was placed on a 20 x 1 cm 2 The mixture was cut into thin slices. Twenty slices of each multilayer plastic structure were placed in a 2 wt.% aqueous solution of sodium hydroxide at 80°C and 500 rpm for 15 minutes. The supernatant was saved. This was repeated two more times. The flakes were then rinsed to remove the aqueous sodium hydroxide solution. The flakes were allowed to settle for 10 minutes, and if necessary, the floating flakes were separated from the settled flakes, and the mass of each was recorded (given their different densities, the OPP flakes should float and the PET flakes should sink). The results are shown in Table 8 below. If delamination occurred, 40 flakes had to be identified (20 PET polymer films and 20 OPP polymer films), i.e., 20 flakes of the multilayer plastic structure were separated into 2 x 20 flakes of the component plastic materials. The flakes were dried in an oven at 105°C. When peeled off, the L of the thin piece * , a * and b * Values ​​were measured on an X-rite eXact spectrophotometer (average of 10 measurements taken) and the results are shown in Table 9 below.

[0237] result

[0238] [Table 8] The multi-layer plastic structure of Example 10 delaminates when exposed to an alkaline aqueous solution, separating the individual, distinct layers of the PET and OPP polymer films of the multi-layer plastic structure. In contrast, no delamination occurred in the multilayer plastic structure of Comparative Example 10a. Only 20 flakes were obtained. These flakes settled because the combined density of the PET and OPP polymer films was greater than the density of water. The results obtained for the multilayer plastic structure of Example 10 are shown in Table 1. * , a * and b * Values ​​were compared to uncoated PET and OPP sample strips (controls), respectively. In the CIELAB color system (CIELAB color space) - a color space defined by the International Commission on Illumination (CIE) in 1976 - L * represents the lightness, and a * represents the red / green value, and b * represents the yellow / blue value. The ΔE measurements were then calculated using a white background, and the results are shown in Table 9 below. ΔE is a standard mathematical calculation that allows for the quantification of the visual perception of the difference between two colors (here, the difference between a control and a thin piece of PET or OPP obtained from the multilayer plastic structure of Example 10). ΔE is calculated using the following formula: L = L * , a=a * and b=b * ) is calculated using

[0239]

number

[0240] [Table 9]

Claims

1. Use of a first composition comprising a protein for removing a mark or image from a plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution, optionally wherein the plastic substrate has the first composition comprising the protein and a second composition applied directly to at least a portion thereof, the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and wherein a mark or image can be formed when a localized portion of the second composition is irradiated with a laser, and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator.

2. 1. Use of a first composition for producing a plastic substrate, at least a portion of which is coated with or at least a portion of which is incorporated a first composition and a second composition applied thereon, the first composition comprising a protein; and the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye. The second composition displays a mark or image formed by irradiating a localized portion of the second composition with a laser, so that the plastic substrate displays the mark or image. When the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator. Preferably, the mark or image can be removed from the plastic substrate by exposing the plastic substrate to an alkaline aqueous solution, providing a plastic material that is not contaminated by the second composition. Optionally, the production of the plastic substrate comprises applying the first composition and the second composition onto the plastic substrate or a component of its plastic material, preferably by printing the first composition and the second composition onto the plastic substrate or a component of its plastic material, more preferably by pad printing, screen printing, flexographic printing, or gravure printing.

3. A plastic substrate having applied to at least a portion thereof or having incorporated therein a first composition containing a protein and a second composition applied on the first composition, wherein the second composition contains a coloring compound selected from the group consisting of an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and wherein a mark or image can be formed when a localized portion of the second composition is irradiated with a laser, and when the coloring compound is a leuco dye, the second composition further contains a thermal acid generator.

4. 4. The plastic substrate of claim 3, formed by a process comprising applying the first composition and the second composition onto the plastic substrate or a component of its plastic material, preferably by printing the first composition and the second composition onto the plastic substrate or a component of its plastic material, more preferably by pad printing, screen printing, flexographic printing or gravure printing.

5. A use of a first composition and a second composition in removing a mark or image from a plastic substrate to provide a plastic material that is not contaminated by the second composition, wherein the first composition containing a protein and the second composition applied over the first composition are applied to or incorporated into at least a portion of the plastic substrate, the second composition containing a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye, and the mark or image is formed by irradiating a localized portion of the second composition with a laser, resulting in the plastic substrate displaying the mark or image, and when the coloring compound is a leuco dye, the second composition further contains a thermal acid generator, and the mark or image is removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution.

6. A method for removing a mark or image from a plastic substrate and providing a plastic material that is not contaminated with a second composition, the method comprising: applying a first composition containing a protein and a second composition applied over the first composition to at least a portion of the plastic substrate, or incorporating the first composition into at least a portion of the plastic substrate; the second composition comprising a coloring compound selected from an oxyanion or oxyacid of a polyvalent metal or a hydrate thereof and a leuco dye; and displaying a mark or image formed by irradiating a localized portion of the second composition with a laser, such that the plastic substrate displays the mark or image; and when the coloring compound is a leuco dye, the second composition further comprises a thermal acid generator; and the method comprises exposing the plastic substrate to an alkaline aqueous solution.

7. 7. The use, plastic substrate or method according to any one of claims 1 to 6, wherein the coloured compound is a leuco dye and the second composition further comprises a thermal acid generator selected from amine salts of organometallic compounds, an organic solvent, and an alkaline stabiliser having a pKa of from 2 to 12.

8. A composition comprising a leuco dye, a thermal acid generator selected from amine salts of organometallic compounds, an organic solvent, and an alkaline stabilizer having a pKa of 2-12.

9. 10. Use of the composition of claim 8 in a method for removing a mark or image from a plastic substrate to provide a plastic material that is not contaminated by the composition, wherein the plastic substrate has applied to it at least a portion thereof a first composition comprising a protein and the composition applied over the first composition, the leuco dye of the composition displaying a mark or image, the mark or image being formed by irradiating a localized portion of the composition using a laser, such that the plastic substrate displays a mark or image, and the mark or image can be removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution, to provide a plastic material that is not contaminated by the composition.

10. 10. Use of the composition of claim 8 for producing a plastic substrate having a first composition comprising a protein and the composition applied thereon applied to at least a portion thereof or incorporated into at least a portion thereof, wherein the leuco dye displays a mark or image, and the mark or image is formed by irradiating a localized portion of the composition using a laser, so that the plastic substrate displays a mark or image, and the mark or image can be removed from the plastic substrate, preferably by exposing the plastic substrate to an alkaline aqueous solution, to provide a plastic material that is not contaminated by the composition, and optionally, producing the plastic substrate comprises applying the first composition and the composition onto the plastic substrate or a component of its plastic material, preferably by printing the first composition and the composition onto the plastic substrate or a component of its plastic material, more preferably by pad printing, screen printing, flexographic printing or gravure printing.

11. A plastic substrate having the composition of claim 8 applied thereon.

12. 10. A plastic substrate comprising the composition of claim 8 applied to or incorporated into at least a part thereof, the plastic substrate being formed by a process comprising applying the composition onto the plastic substrate or a component of its plastic material, preferably by printing the composition onto the plastic substrate or a component of its plastic material, more preferably by pad printing, screen printing, flexographic printing or gravure printing.

13. 11. The use, plastic substrate or method according to any one of claims 1, 2, 5, 6, 7, 9 or 10, wherein the alkaline aqueous solution is an aqueous solution of 0.1 to 5 wt. %, such as 0.5 to 3 wt. %, preferably 1 to 3 wt. % of a base, preferably an alkali or alkaline earth hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide, preferably sodium hydroxide, optionally at a temperature of 50 to 95°C, for example 60 to 95°C, or 80 to 95°C, such as 80 to 90°C.

14. 14. The use, plastic substrate or method of any one of claims 1, 2, 5, 6, 7, 9, 10 or 13, wherein after exposure to the alkaline solution the second composition remains as a solid or precipitate and is preferably removed by filtration.

15. 15. The use, method or plastic substrate according to any one of claims 1 to 7 and 13 or 14, wherein the polyvalent metal oxyanion or oxyacid or hydrate thereof is a polyvalent metal oxyanion or a hydrate of a polyvalent metal oxyanion, preferably an ammonium salt of a polyvalent metal oxyanion, preferably an ammonium salt of a molybdenum oxyanion, preferably ammonium octamolybdate (AOM).

16. The heat generating agent is represented by formula (I): 【Chemistry 1】 wherein X is silicon or boron, and E and F are the same or different: 【Chemistry 2】 is selected from the group consisting of Here, R ６ and R ７ and may be the same or different from hydrogen, C １～４ -Alkyl, C １～４ -alkoxy, halogen, amino or carboxy, When X=silicon, o=1 and p=0, and R １ is aryl, aralkyl or C １～４ - alkyl, or o=1 and p=1, and R １ and R ２ And together they are: 【Transformation 3】 and forming one residue selected from the group consisting of: When X=boron, o=0 and p=0, and R ３ , R ４ and R ５ are the same or different, hydrogen, C １～１２ -Alkyl, C １～６ -hydroxyalkyl, allyl, aralkyl or arylsulfonyl, where aralkyl or arylsulfonyl is C １～４ -alkyl or R ３ and R ４ together with the nitrogen to which they are attached form a morpholino or piperidino ring) The use, plastic substrate, composition or method according to any one of claims 7 to 14, wherein the organometallic compound is an amine salt of the formula:

17. 17. The use, plastic substrate, composition or method according to any one of claims 7 to 14 or 16, wherein the alkaline stabilizer having a pKa of 2 to 12 has a pKa of 4 to 11, preferably 6 to 11, preferably the alkaline stabilizer having a pKa of 2 to 12 is selected from sodium carbonate, sodium bicarbonate, potassium carbonate, monoethanolamine and triethanolamine, or combinations thereof, more preferably the alkaline stabilizer having a pKa of 2 to 12 is sodium bicarbonate.

18. 18. The use, plastic substrate or method according to any one of claims 1 to 7, 10 or 13 to 17, wherein the protein of the first composition is selected from collagen (hydrolysed or not), such as hydrolysed bovine collagen, gelatin, egg white, whey, casein, and prolamin proteins such as gluten, zein, soybean, pea and hemp, preferably the protein of the first composition is a prolamin protein selected from gluten, zein, soybean, pea and hemp, more preferably zein or soybean, more preferably zein.

19. 19. The method, use or plastic substrate according to any one of claims 1 to 7 and 9 to 18, wherein the plastic substrate is plastic packaging, preferably a plastic container, more preferably a plastic box, a plastic pouch, a plastic bottle, a plastic blister pack or a plastic clamshell pack, more preferably a plastic box, a plastic pouch or a plastic bottle, most preferably a plastic bottle.

20. 20. The method, use or plastic substrate according to any one of claims 1 to 7 and claims 9 to 19, wherein the plastic substrate is formed from polyethylene terephthalate (PET), high density polyethylene (HDPE), polypropylene (PP), recycled polyethylene terephthalate (r-PET), low density polyethylene (LDPE), or a combination thereof, preferably polyethylene terephthalate (PET) or recycled polyethylene terephthalate (r-PET), more preferably polyethylene terephthalate (PET).

21. 21. The plastic substrate according to any one of claims 3, 4, 5, 7, and 11 to 20, wherein the colored compound of the second composition or the composition containing a leuco dye displays a mark or an image, and the mark or image is formed by irradiating a localized portion of the second composition or the composition containing a leuco dye using a laser.

22. 22. The plastic substrate of any one of claims 3, 4, 5, 7, and 11-21, which is a multilayer plastic structure, preferably the multilayer plastic structure comprises two or more layers of plastic material, and at least one layer of the first composition and the second composition disposed between two plastic material layers.

23. A method for displaying a mark or image on a plastic substrate according to any one of claims 3, 4, 5, 7, and 11 to 20, or 22, comprising irradiating a localized portion of the second composition or the composition containing the leuco dye using a laser.

24. The radiation applied to the localized location includes ultraviolet (UV) radiation having a wavelength of 10 to 400 nm, near-infrared (NIR) radiation having a wavelength of 700 to 1600 nm, infrared (IR) radiation having a wavelength of 700 nm to 1 mm, preferably infrared (IR) radiation having a wavelength of 9000 to 12000 nm, infrared radiation having a wavelength of 700 nm to 1 mm, and near-infrared (NIR) radiation having a wavelength of 700 to 1600 nm, more preferably 9300, 960 24. The method, use or plastic substrate according to any one of claims 2 to 7, 10 and 13 to 23, wherein the radiation is selected from infrared (IR) radiation having a wavelength of 10, 10200 or 10600 nm, infrared radiation having a wavelength of 700 nm to 1 mm, and near infrared (NIR) radiation having a wavelength of 700 to 1600 nm, most preferably infrared (IR) radiation having a wavelength of 10600 nm and near infrared (NIR) radiation having a wavelength of 950 to 1100 nm.

25. 23. A method of forming a plastic substrate according to any one of claims 3, 4, 7 and 11 to 22, comprising applying the first composition and the second composition or the composition comprising a leuco dye onto the plastic substrate or a component of the plastic material thereof, preferably by printing the first composition and the second composition or the composition comprising a leuco dye onto the plastic substrate or a component of the plastic material thereof, more preferably by pad printing, screen printing, flexographic printing or gravure printing.

26. A method for forming a plastic substrate and forming a mark or image thereon, the method comprising: applying a composition comprising a first composition and a second composition or a leuco dye onto the plastic substrate or a component of the plastic material thereof; and printing the composition comprising the first composition and the second composition or the leuco dye onto the plastic substrate or a component of the plastic material thereof, preferably by pad printing, screen printing, flexographic printing or gravure printing, and irradiating a localized portion of the composition comprising the second composition or the leuco dye using a laser to form a mark or image thereon; preferably, the applied radiation is ultraviolet (UV) radiation having a wavelength of 10 to 400 nm, near-infrared (NIR) radiation having a wavelength of 700 to 1600 nm.

23. A method for forming a plastic substrate according to any one of claims 3, 4, 7, and 11 to 22, and forming a mark or image thereon, comprising:

Images