Composition

Abstract

The present invention is directed to a composition comprising a near-infrared absorbing compound, a color-forming compound, and a heat transfer agent operable to facilitate heat transfer from the near-infrared absorbing compound to the color-forming compound, wherein the near-infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the total composition, the heat transfer agent is present in an amount of 1 to 15 wt % of the total composition, and the heat transfer agent is present in the composition as solid particles. The present invention further relates to a substrate comprising the composition for application thereto, as well as a method for forming a color or image on said substrate.

Description

[Technical field]

[0001] The present invention relates to compositions for use in forming images via the application of near or mid-infrared radiation. [Background technology]

[0002] The use of near infrared (NIR) radiation and near infrared absorbing compounds to affect color forming compounds in radiation responsive compositions applied onto or incorporated into a substrate is known. When exposed to near infrared radiation, the near infrared absorbing compound can absorb the near infrared radiation and transfer this energy to the color forming compound as heat to effect a change in the color forming compound such that the color forming compound forms a color.

[0003] In known systems, a sufficient amount of near infrared absorbing compound must be present in the composition in close proximity to the color-forming compound to achieve a suitable amount of heat transfer from the near infrared absorbing compound to the color-forming compound. However, known near infrared absorbing compounds are typically highly colored to the human eye, with the visible region adjacent to the near infrared region of the electromagnetic spectrum. Accordingly, the amount of near infrared absorbing compound required often negatively impacts the appearance of the radiation-reactive composition and the substrate on which the composition is applied, and highly colored near infrared absorbing compounds create a highly colored background. Such strong background color is detrimental to the formation of color or image on the radiation-reactive composition applied to the substrate.

[0004] Binder and carrier components, etc., are commonly utilized in such radiation-responsive compositions. These components consist of insulating materials, such as insulating polymers, that destructively absorb heat from the near-infrared absorbing compound. Therefore, if the near-infrared absorbing compound and the color-forming compound in the composition are too far apart to transfer sufficient heat to the color-forming compound, the components will melt or soften, resulting in poor color formation. To combat this effect, insulating materials with high glass transition temperatures (Tg) and high minimum film-forming temperatures (MFFT) are typically selected as binder and carrier components. Such materials do not begin to negatively absorb heat from the near-infrared absorbing compound and do not exhibit the detrimental softening or melting effects. In addition, high-power near-infrared sources may be utilized to further combat this effect. However, this is problematic when the radiation-responsive composition is applied to a fragile heat-sensitive substrate. Summary of the Invention

[0005] It is therefore desirable to provide a composition that promotes efficient heat transfer from the near infrared absorbing compound to the color forming compound upon application of near infrared radiation to the composition, providing improved and efficient color formation suitable for forming a color or image on a substrate.

[0006] According to a first aspect of the present invention, there is provided a composition comprising a near-infrared absorbing compound, a color-forming compound, and a heat transfer agent that functions to promote heat transfer from the near-infrared absorbing compound to the color-forming compound, wherein a ratio of the near-infrared absorbing compound to the heat transfer agent in the composition is 1:1 to 1:100, and the heat transfer agent is present in the composition as solid particles.

[0007] According to a second aspect of the present invention, there is provided a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent that functions to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent is present in an amount of 1 to 15 wt % of the composition, and the heat transfer agent is present in the composition as solid particles.

[0008] According to a third aspect of the present invention, there is provided a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate transfer of heat from the near infrared absorbing compound to the color forming compound, wherein the heat transfer agent is selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and the heat transfer agent is present in the composition as solid particles.

[0009] According to a fourth aspect of the present invention, there is provided a substrate comprising the composition as applied above, wherein the composition comprises a near infrared absorbing compound, a color forming compound, and a heat transfer agent that functions to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1 to 1:100, and the heat transfer agent is present in the composition as solid particles.

[0010] According to a fifth aspect of the present invention, there is provided a substrate comprising the composition as applied above, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the colour forming compound, the near infrared absorbing compound being present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent being present in an amount of 1 to 15 wt % of the composition, and the heat transfer agent being present in the composition as solid particles.

[0011] According to a sixth aspect of the present invention, there is provided a substrate comprising the composition as applied above, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the heat transfer agent being selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and the heat transfer agent being present in the composition as solid particles.

[0012] According to a seventh aspect of the present invention, there is provided a method of forming a substrate comprising applying to the substrate a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent that serves to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein a ratio of the near infrared absorbing compound to the heat transfer agent in the composition is from 1:1 to 1:100, and the heat transfer agent is present in the composition as solid particles.

[0013] According to an eighth aspect of the present invention, there is provided a method of forming a substrate comprising applying to the substrate a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent is present in an amount of 1 to 15 wt % of the composition, and the heat transfer agent is present in the composition as solid particles.

[0014] According to a ninth aspect of the present invention, there is provided a method of forming a substrate comprising applying to the substrate a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein the heat transfer agent is selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and the heat transfer agent is present in the composition as solid particles.

[0015] According to a tenth aspect of the present invention there is provided a method of forming a colour on a substrate comprising applying a composition thereon, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the colour forming compound, wherein the ratio of near infrared absorbing compound to heat transfer agent in the composition is from 1:1 to 1:100, and the heat transfer agent is present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to form a colour on the substrate.

[0016] According to an eleventh aspect of the present invention there is provided a method of forming a colour on a substrate comprising applying a composition thereon, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the colour forming compound, the near infrared absorbing compound being present in an amount of 0.1 to 3.5 wt % of the composition and the heat transfer agent being present in an amount of 1 to 15 wt % of the composition, the heat transfer agent being present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to cause the formation of a colour on the substrate.

[0017] According to a twelfth aspect of the present invention there is provided a method of forming a colour on a substrate comprising applying a composition thereon, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent operable to facilitate transfer of heat from the near infrared absorbing compound to the colour forming compound, the heat transfer agent being selected from a metal oxide, a metal pyrophosphate and a metal phosphate, the heat transfer agent being present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to cause the colour to form on the substrate.

[0018] According to a thirteenth aspect of the present invention, there is provided a method of forming an image on a substrate comprising the composition applied above, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent which serves to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the ratio of near infrared absorbing compound to heat transfer agent in the composition being from 1:1 to 1:100, and the heat transfer agent being present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0019] According to a fourteenth aspect of the present invention there is provided a method of forming an image on a substrate comprising a composition as applied above, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the colour forming compound, the near infrared absorbing compound being present in an amount of 0.1 to 3.5 wt % of the composition and the heat transfer agent being present in an amount of 1 to 15 wt % of the composition and the heat transfer agent being present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0020] According to a fifteenth aspect of the present invention there is provided a method of forming an image on a substrate comprising the composition applied above, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the heat transfer agent being selected from metal oxides, metal pyrophosphates, and metal phosphates, the heat transfer agent being present in the composition as solid particles, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0021] According to a sixteenth aspect of the present invention, there is provided a use of a composition in forming a color on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a color-forming compound, and a heat transfer agent that serves to facilitate heat transfer from the near infrared absorbing compound to the color-forming compound, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition being 1:1 to 1:100, and the heat transfer agent being present in the composition as solid particles.

[0022] According to a seventeenth aspect of the present invention, there is provided use of a composition in forming a colour on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a colour forming compound and a heat transfer agent which acts to facilitate transfer of heat from the near infrared absorbing compound to the colour forming compound, the near infrared absorbing compound being present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent being present in an amount of 1 to 15 wt % of the composition and the heat transfer agent being present in the composition as solid particles.

[0023] According to an eighteenth aspect of the present invention, there is provided use of a composition in forming a color on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate transfer of heat from the near infrared absorbing compound to the color forming compound, the heat transfer agent being selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and the heat transfer agent being present in the composition as solid particles.

[0024] According to a nineteenth aspect of the present invention, there is provided a use of a composition in forming an image on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a color-forming compound, and a heat transfer agent that functions to facilitate heat transfer from the near infrared absorbing compound to the color-forming compound, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition being 1:1 to 1:100, and the heat transfer agent being present in the composition as solid particles.

[0025] According to a twentieth aspect of the present invention, there is provided use of a composition in forming an image on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent that serves to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the near infrared absorbing compound being present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent being present in an amount of 1 to 15 wt % of the composition, and the heat transfer agent being present in the composition as solid particles.

[0026] According to a twenty-first aspect of the present invention, there is provided a use of a composition in forming an image on a substrate by application of near infrared or mid-infrared radiation, the composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent which serves to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, the heat transfer agent being selected from metal oxides, metal pyrophosphates, and metal phosphates, and the heat transfer agent being present in the composition as solid particles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Surprisingly and advantageously, the incorporation of solid particles of a heat transfer agent in the composition of the present invention can make the heat transfer from the near infrared absorbing compound to the color forming compound substantially more efficient, promoting greatly improved and surprisingly more effective color formation by the color forming compound when near infrared radiation is applied to the composition. Advantageously, the same effective color formation was also demonstrated when mid infrared radiation was applied to the composition. In addition, surprisingly and advantageously, it was discovered that the selection of (a) a specific heat transfer agent, (b) a specific amount of near infrared absorbing compound and heat transfer agent, and (c) a specific ratio of near infrared absorbing compound and heat transfer agent in the composition promotes improved color formation by the color forming compound. Color formation can occur at reduced fluence (amount of energy delivered by unit area) when the composition is exposed to near infrared or mid infrared radiation from a laser source by minimizing heat lost to any binder and carrier components from detrimental effects such as softening and melting. In addition, the amount of highly colored near infrared absorbing compound utilized in the composition can be reduced so that the composition can exhibit low background color. This not only reduces costs associated with expensive near infrared absorbing compounds, but ultimately, the compositions of the present invention demonstrate improved coating integrity, allowing for faster imaging speeds and requiring lower power, particularly lower fluence, near infrared sources. The use of low power, particularly low fluence, near infrared sources is particularly advantageous when the compositions are applied to perishable, heat-sensitive substrates.

[0028] It has further been surprisingly and advantageously discovered that as a result of incorporating a heat transfer agent into a composition comprising a near infrared absorbing compound and a color forming compound, a wide range of binder and carrier components can be utilized in said composition.Previously, the binder and carrier components had to be formed from insulating materials that require a high glass transition temperature (Tg) and a high minimum film-forming temperature (MFFT) to withstand the heat transferred from the near infrared absorbing compound to the binder and carrier components.In accordance with the present invention, the presence of the heat transfer agent means that a wide range of binder and carrier components can be utilized, particularly binder and carrier components with low glass transition temperatures and low minimum film-forming temperatures.This facilitates a wider commercial application of the composition of the present invention to a wide range of substrates, including heat-sensitive substrates, particularly polymeric films and foils.

[0029] It has also been surprisingly and advantageously determined that the benefits of the present invention are much greater than those achieved by (a) increasing the amount of near infrared absorbing compound in the composition, which would not only be expensive, but would also result in a highly colored background in the composition and would result in excessive heat being transferred to the composition and color forming compound, with detrimental effects on image formation and leading to poor color formation, particularly due to detrimental effects such as softening and melting and decomposition, burning, scorching or ablation, and the like, and (b) increasing the amount of color forming compound in the composition, which would not only be expensive, but would also require the near infrared absorbing compound to facilitate increased heat transfer to fully utilize the additional color forming compound, with detrimental effects such as softening and melting and dilution, decomposition, burning, scorching or ablation, and the like, leading to ineffective color formation.

[0030] According to a first aspect of the present invention, there is provided a composition comprising a near-infrared absorbing compound, a color-forming compound, and a heat transfer agent that functions to promote heat transfer from the near-infrared absorbing compound to the color-forming compound, wherein a ratio of the near-infrared absorbing compound to the heat transfer agent in the composition is 1:1 to 1:100, and the heat transfer agent is present in the composition as solid particles.

[0031] According to a second aspect of the present invention, there is provided a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent that functions to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the composition, the heat transfer agent is present in an amount of 1 to 15 wt % of the composition, and the heat transfer agent is present in the composition as solid particles.

[0032] According to a third aspect of the present invention, there is provided a composition comprising a near infrared absorbing compound, a color forming compound, and a heat transfer agent operable to facilitate transfer of heat from the near infrared absorbing compound to the color forming compound, wherein the heat transfer agent is selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and the heat transfer agent is present in the composition as solid particles.

[0033] The near infrared absorbing compound may be any suitable compound capable of absorbing near infrared or mid-infrared, preferably near infrared. Multiple near infrared absorbing compounds may be present in the composition according to the first, second or third aspect of the present invention. Suitable examples of near infrared absorbing compounds include, but are not limited to, 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); reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide, reduced doped tungsten oxide [inorganic compounds of the following formula MxWyOz, where M is H, He, alkali metal, alkaline earth metal, rare earth element, 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, O is oxygen, and 0.001≦x / y≦1 and 2.2≦z / y≦3.0 are included], non-stoichiometric reduced or doped inorganic compounds such as reduced antimony tin oxide, or doped metal oxides such as aluminum doped zinc oxide (AZO) and fluorine doped tin oxide (FTO); conductive polymers such as polystyrene sulfonate (PEDOT); and combinations thereof. The near infrared absorbing compound may be an inorganic copper salt, such as copper(II) hydroxyl phosphate.

[0034] The near infrared absorbing compound may have any suitable D50 particle size distribution value. The D50 particle size distribution is the average diameter or mean value of the particle size distribution, i.e., 50% particle size in the cumulative distribution. Preferably, the D50 particle size distribution value of the near infrared absorbing compound is 5 μm or less. More preferably, the D50 particle size distribution value of the near infrared absorbing compound is 0.5-3 μm, most preferably 1-2 μm. The D50 particle size distribution is measured using a Malvern Mastersizer according to ISO standard 13320:2009.

[0035] Preferably, the near infrared absorbing compound is an inorganic copper salt, such as copper(II) hydroxyl phosphate; and reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide, reduced doped tungsten oxide [inorganic compounds of the formula MxWyOz, where M is H, He, an alkali metal, an alkaline earth metal, a rare earth element, 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 , at least one element selected from the group consisting of S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, and ammonium, where W is tungsten and O is oxygen, and 0.001≦x / y≦1 and 2.2≦z / y≦3.0 are satisfied], non-stoichiometric reduced or doped inorganic compounds such as reduced antimony tin oxide, or doped metal oxides such as aluminum doped zinc oxide (AZO) and fluorine doped tin oxide (FTO).

[0036] The color forming compound may be any suitable compound that forms color upon exposure of the composition to near or mid-infrared radiation.

[0037] It will be understood that the color forming compound is selected based on the color desired in the image formed.

[0038] The colour forming compound may be selected from leuco dyes, oxoanions of polyvalent metals, diacetylene compounds, ketoacid compounds, or combinations thereof. There may be more than one colour forming compound present in the composition according to the first, second or third aspect of the invention.

[0039] Preferably, the color-forming compound is selected from leuco dyes, polyvalent metal oxoanions, and diacetylene compounds. More preferably, the color-forming compound is a leuco dye or a polyvalent metal oxoanion. Most preferably, the color-forming compound is a leuco dye.

[0040] Leuco Dyes The color-forming compound may be a leuco dye. Leuco dyes are well known to those skilled in the art as compounds that can form color. Examples of suitable leuco dyes are included in WO 2015 / 015200 and WO 2013 / 068729, the contents of which are incorporated herein by reference. Examples of suitable leuco dyes include, but are not limited to: 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.

[0041] Suitable suppliers of leuco dyes include, but are not limited to: Yamada Chemical Industry Co., Ltd., Chameleon Speciality Chemicals Limited, and Connect Chemicals.

[0042] The leuco dyes are: 2-anilino-3-diethylamino-6-methylfluoran, 2-anilino-6-dibutylamino-3-methylfluoran, 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]phthalide, 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline], 3,3'-bis(1-n-octyl-2-methylindol-3-yl)phthalide, 6'-(diethylamino)-3-oxo-spiro[isobenzofuran-1(3H), 9'-[9H]xanthene]-2'-carboxylic acid ethyl ester, 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl-1-octyl-1H-indol-3-yl)furo[3,4-b]pyridin-5(7H)-one, 2'-(dibenzylamino)-6'-(diethylamino)fluoran, N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl]-benzenamine, and 6'-(diethylamino)-2'-[(dimethylphenyl)amino]- 3'-Methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, 2'-anilino-6'-[ethyl(p-tolyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS number 59129-79-2), 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline] (CAS number 67707-04-4), 6'-(diethylamino)-3-oxo-spiro[isobenzofuran 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS number 34372-72-0), 2'-anilino-6'-(dibutylamino)-3'-methyl-3H-spiro[2-benzofuran-1,9'-xanthene]-3-one (CAS number 89331-94-2), 6'-(diethylamino)-3'-methyl-2'-(phenylamino)spiro[2-benzofuran-3,9'-xanthene]-1-one (CAS number 29512-49-0), 2-anilino-6'-[ethyl(p-toyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS number 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]xanthen]-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), 2-anilino-3-diethylamino-6-methylfluoran, 2-anilino-6-dibutylamino-3-methylfluoran, 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]phthalide, 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline], 3,3'-bis(1-n-octyl-2-methylindol-3-yl)phthalide, 6'-(diethylamino)-3-oxo-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-2'-carboxylic acid ethyl ester, 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl-1-octyl-1H-indol-3-yl)furo[3,4-b]pyridin-5(7H)-one, 2'-(dibenzylamino)-6'-(diethylamino)fluoran, N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl nyl]-benzenamine, and 6'-(diethylamino)-2'-[(dimethylphenyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline] (CAS number 67707-04-4), 6'-(diethylamino)-3-oxo-spiro[isobenzofuran-1(3H),9'-(9H)xanthene]-2'-carboxylic acid ethyl ester (CAS number 154306-60-2), and 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS number 34372-72-0).

[0043] Preferably, the leuco dye is 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]phthalide, 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl-1-octyl-1H-indol-3-yl)furo[3,4-b]pyridin-5(7H)-one, 3,3'-bis(1-n-octyl-2-methylindol-3-yl)phthalide, N,N-dimethyl-4-[2-[2-( octyloxy)phenyl]-6-phenyl-4-pyridinyl]-benzenamine, 6'-(diethylamino)-2'-[(dimethylphenyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, 2'-anilino-6'-[ethyl(p-tolyl)amino]-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS no. 59129-79-2), 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N-phenylaniline] (CAS number 67707-04-4), 6'-(diethylamino)-3-oxo-spiro[isobenzofuran-1(3H),9'-(9H)xanthene]-2' carboxylic acid ethyl ester (CAS number 154306-60-2), 2'-anilino-6'-(dibutylamino)-3 '-Methyl-3H-spiro[2-benzofuran-1,9'-xanthene]-3-one (CAS number 89331-94-2), 6'-(diethylamino)-3'-methyl-2'-(phenylamino)spiro[2-benzofuran-3,9'-xanthene]-1-one (CAS number 29512-49-0) and 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS number 34372-72-0).

[0044] Preferably, the leuco dye is 2-anilino-3-diethylamino-6-methylfluoran or 2-anilino-6-dibutylamino-3-methylfluoran.

[0045] Polyvalent metal oxoanions The color-forming compound may be a polyvalent metal oxoanion, or an oxoacid, and / or a hydrate thereof. The polyvalent metal oxoanion may be any suitable oxoanion of a polyvalent metal (anionic component) present in conjunction with a cationic counterpart. The use of polyvalent metal oxoanions in compositions is disclosed in U.S. Pat. No. 7,485,403, the contents of which are incorporated herein by reference. The anionic component may be an inorganic metal oxoanion compound, such as molybdate, including di-, tri-, hexa-, hepta-, octa- and deca-molybdate, tungstate, chromate, or similar transition metal compounds of mixed oxidation states and mixed inorganic metal oxoanions, in trace elements or any high concentration ratio. Preferably, the associated cationic component is an alkali metal or alkaline earth metal or ammonium. An example of a polyvalent metal oxoanion is sodium molybdate. A preferred polyvalent metal oxoanion is an ammonium salt of an inorganic metal oxoanion compound. For example, ammonium paratungstate (APT). Particularly preferred as the polyvalent metal oxoanion is an ammonium salt of a polyvalent metal oxoanion. A particularly preferred polyvalent metal oxoanion is ammonium octamolybdate (NH4)4Mo8O 26 or "AOM," a molybdenum composition commercially available under the CAS number 12411-64-2.

[0046] Preferably, the polyvalent metal oxoanion is an ammonium salt of a polyvalent metal oxoanion, such as an ammonium salt of a molybdenum oxoanion. More preferably, the polyvalent metal oxoanion is ammonium octamolybdate (AOM).

[0047] Diacetylene Compounds The color-forming compound is a diacetylene compound, i.e.,

[0048] [ka] The compound may be a compound comprising:

[0049] Diacetylene compounds are well known to those skilled in the art as compounds that can form color. When exposed to a stimulus, diacetylene compounds typically polymerize to show color. Exemplary diacetylene compounds are disclosed in WO 2012 / 114121, the contents of which are incorporated herein by reference for this purpose. Suitable examples are also taught in WO 2009 / 093028, WO 2010 / 001171, WO 2010 / 029329, and WO 2013 / 068729, the contents of each of which are incorporated herein by reference. Known methods for the synthesis of diacetylene compounds include the formation of reactive acid chlorides followed by the addition of amines or alcohols, or the formation of mixed anhydrides followed by reaction with amines or alcohols. In the case of the diacetylene compounds disclosed herein, such synthesis may also include the introduction of a protecting group P.

[0050] Diacetylene compounds can typically exhibit multiple colors. In the context of the present invention, it is understood that after the composition according to the first, second and third aspects of the present invention is applied to a substrate, a stimulus such as ultraviolet light can typically be applied to cause the diacetylene compounds to form an initial first color. Then, near infrared or mid infrared light can be applied to cause the diacetylene compounds to form a second color.

[0051] Prior to this initial first color formation, certain diacetylenic compounds (e.g., diacetylenic compounds of formulas (I) and (II)) may need to be preferentially "activated" (i.e., to allow color formation) before exposure to a stimulus (e.g., ultraviolet light) that affects the initial first color of the diacetylenic compound. This can allow color formation by the diacetylenic compound. "Activation" is the process of allowing the diacetylenic compound to change from an inactivated form (not capable of forming color) to an activated form (capable of forming color) in which color can be formed. Optionally, activation can be accelerated by exposing the diacetylenic compound to an activation temperature. It will be understood by those skilled in the art that this activation may occur before exposure to a stimulus to form the first initial color, or alternatively, the diacetylenic compound may be activated during this exposure. Preferably, activation occurs before exposure to a stimulus to cause the formation of the first initial color. If activation is performed prior to exposure to a stimulus to form the first initial color, the activation temperature is between ambient temperature (10-35°C) and the thermal decomposition temperature of the diacetylenic compound. The activation temperature may be 40-150°C. Preferably, the activation temperature is 60-140°C, for example 70-140°C. The diacetylenic compound may be exposed to the activation temperature using any suitable means, including a radiation source such as a laser source. The radiation may be selected from visible light with wavelengths of 400-700 nm, infrared with wavelengths of 700 nm-1 mm, and near infrared with wavelengths of 780-1600 nm. The fluence of the laser source may be varied as discussed below. The diacetylenic compound may also be exposed to the activation temperature using a water vapor source and a conductive temperature source, including, but not limited to, hot air, lamps, heat tunnels, LEDs, thermal print heads, thermal conductors, hot liquids, hot plates, and heated substrates.

[0052] The color-forming compound has the following formula (I):

[0053] [ka] The diacetylene compound may have the formula: In the formula, x is 2 to 12, preferably 2 to 10. L is a group represented by the formula:

[0054] [ka] and amides having the formula:

[0055] [ka] and preferably L is selected from esters having the formula

[0056] [ka] is an amide having the formula Q is C 1~20 Alkyl groups and C 3~18 Preferably, Q is selected from cycloalkyl groups, such as cyclopropyl and -(CH2) y -CH3 alkyl straight chain, y is selected from 1 to 20, preferably 5 to 19, more preferably 5 to 17; T is hydrogen, C 1~20 Alkyl groups, and -(CH2) x -LQ, where x, L and Q are as defined above, and preferably T is hydrogen, -(CH) y -(CH3) alkyl straight chain, where y is as defined above, and -(CH2) x -LQ, where x, L and Q are as defined above.

[0057] The diacetylene compound of formula (I) may be either symmetrical or asymmetrical, i.e., T is -(CH2) x -LQ, where the values ​​of x, L and Q are the same as those of the other diacetylene moiety (symmetric), or T is hydrogen, C 1~20 Alkyl group, or -(CH2) xIt will be appreciated by those skilled in the art that the values ​​of x, L and Q are not the same on both sides of the diacetylene moiety (asymmetric). Preferably, T is -(CH2) x -LQ, where the values ​​of x, L and Q are the same on both sides of the diacetylene moiety, and therefore the diacetylene compound of formula (I) is symmetrical.

[0058] Preferably, the color-forming compound has the following formula (II):

[0059] [ka] is a diacetylene compound having the formula In the formula, x is 2 to 12, preferably 2 to 10. Q is cyclopropyl and -(CH2) y (CH3) alkyl straight chain, wherein y is 1-20, preferably 5-19, and more preferably 5-17.

[0060] Examples of suitable diacetylene compounds include, but are not limited to, N1,N22-dioctadecyldocosa-10,12-diynediamide, N1,N22-dihexadecyldocosa-10-12-diynediamide, N1,N22-ditetradecyldocosa-10,12-diynediamide, N1,N22-didodecyldocosa-10,12-diynediamide, N1,N22-didecyldocosa-10,12-diynediamide, N1,N22-dioctyldocosa-10,12-diynediamide, N1,N22-dihexyldocosa-10,12-diynediamide, and N1,N22-dicyclopropyldocosa-10,12-diynediamide.

[0061] Preferably, the diacetylene compound is a diacetylene compound selected from N1,N22-dioctadecyldocosa-10,12-diynediamide, N1,N22-dihexadecyldocosa-10,12-diynediamide, N1,N22-ditetradecyldocosa-10,12-diynediamide, N1,N22-didodecyldocosa-10,12-diynediamide, and N1,N22-dicyclopropyldocosa-10,12-diynediamide.

[0062] Alternatively, the color-forming compound may be a diacetylenic compound containing a protecting group.

[0063] The term "protecting group" refers to any cleavable organic chemical moiety that can be cleaved / removed from a diacetylenic compound when exposed to certain conditions, including but not limited to acid, base, heat, hydrogenation, radiation, and reduction. Without being bound by theory, the inventors understand that in the context of the present invention, the protecting group is cleaved from the diacetylenic compound when exposed to near-infrared or mid-infrared radiation. It is not necessarily the case that all of the protecting groups (of the diacetylenic compound monomers and polymers defined above) are cleaved. Thus, it is believed that the protecting group according to the present invention can be cleaved when exposed to near-infrared or mid-infrared radiation.

[0064] Examples of suitable protecting groups include, but are not limited to, alkyl and aryloxycarbonyl groups selected from tert-butyloxycarbonyl (BOC), 2,4-dimethylpent-3-yloxycarbonyl (DOC), dioctyl(((docosa-10,12-diynedioyl)bis)azanediyl)bis(ethane-2,1-diyl))dicarbamate (SOC), 9-fluorenylmethyloxycarbonyl, and benzyloxycarbonyl; benzoyl; carboxybenzyl; and allyloxycarbonyl; cycloalkyls such as cyclododecane and cyclooctane; amide groups such as acetamide and trifluoroacetamide; phthalimide; triphenylmethyl; benzylidene; and p-toluenesulfonyl.

[0065] The color-forming compound has the following formula (III):

[0066] [ka] The diacetylene compound may have the formula: In the formula, x is 2 to 12, preferably 2 to 10. L is a group represented by the formula:

[0067] [ka] and amides having the formula:

[0068] [ka] and preferably L is selected from esters having the formula

[0069] [ka] is an amide having the formula y is 0 to 10, preferably 0 to 8, more preferably 0 to 6; E may be absent or present, and when present, E is selected from NH, O and CH2, preferably, E is NH; P is a protecting group, preferably P is selected from alkyl and aryloxycarbonyl groups selected from tert-butyloxycarbonyl (BOC), 2,4-dimethylpent-3-yloxycarbonyl (DOC), dioctyl(((docosa-10,12-diynedioyl)bis(azanediyl))bis(ethane-2,1-diyl))dicarbamate (SOC), 9-fluorenylmethyloxycarbonyl and benzyloxycarbonyl; benzoyl; carboxybenzyl; and allyloxycarbonyl; cycloalkyl such as cyclododecane and cyclooctane; amide groups such as acetamide and trifluoroacetamide; phthalimide; triphenylmethyl; benzylidene; and p-toluenesulfonyl; more preferably P is an alkyl or aryloxycarbonyl group or cycloalkyl, more preferably P is P is selected from tert-butyloxycarbonyl (BOC), benzoyl, carboxybenzyl, cyclododecane, cyclooctane, 9-fluorenylmethyloxycarbonyl, 2,4-dimethylpent-3-yloxycarbonyl (DOC), and dioctyl (((docosa-10,12-diynedioyl)bis(azanediyl))bis(ethane-2,1-diyl)) dicarbamate (SOC); more preferably P is an alkyl or aryloxycarbonyl group; most preferably P is selected from tert-butyloxycarbonyl (BOC), 9-fluorenylmethyloxycarbonyl, benzoyl, carboxybenzyl, 2,4-dimethylpent-3-yloxycarbonyl (DOC), and dioctyl (((docosa-10,12-diynedioyl)bis(azanediyl))bis(ethane-2,1-diyl)) dicarbamate (SOC); T is hydrogen, -(CH2) x (CH3) alkyl straight chain, where x is as defined above, and -(CH2) x -L-(CH2) y -EP, where x, y, L, E and P are as defined above.

[0070] The diacetylene compound of formula (III) may be symmetric or asymmetric, i.e., T is -(CH2) x -L-(CH2) y -EP, where the values ​​of x, y, L, E and P are the same as those on the other side of the diacetylene moiety (symmetrical), or T is hydrogen, -(CH) x (CH3) alkyl straight chain or -(CH2) x -L-(CH2) y It will be appreciated by those skilled in the art that the diacetylene compound of formula (III) is -EP and the values ​​of x, y, L, E and P are different (asymmetric) from those on the other side of the diacetylene moiety. Preferably, the diacetylene compound of formula (III) is symmetric.

[0071] Preferably, the color-forming compound has the following formula (IV):

[0072] [ka] wherein x is 2-10, y is 0-6, P is selected from tert-butyloxycarbonyl (BOC), benzoyl, 9-fluorenylmethyloxycarbonyl, carboxybenzyl, cyclodecane, cyclooctane, 2,4-dimethylpent-3-yloxycarbonyl (DOC) and dioctyl (((docosa-10,12-diynedioyl)bis(azanediyl)bis(ethane-2,1-diyl)) dicarbamate (SOC), and T is -(CH2) x -L-(CH2) y -EP and the values ​​of x, y, L, E and P are the same as those on the other of the diacetylene moieties, ie, the diacetylene compound of formula (IV) is symmetrical.

[0073] Preferably, the diacetylene compound is di-tert-butyl 2,2'-(tetradeca-6,8-diynedioyl)bis(hydrazine-1-carboxylate), di-tert-butyl (((docosa-10,12-diynedioyl)bis(azanediyl))bis(ethane-2,1-diyl)dicarbamate, di-tert-butyl 2,2'-(docosa-10,12-diynedioyl)bis(hydrazine-1-carboxylate), dibenzyl 2,2'-(docosa-10,12-diynedioyl)bis(azanediyl))bis(ethane-2,1-diyl)dicarbamate, tert-butyl 2-(pentacosa-10,12-diynediyl)bis(azanediyl)bis(hexane-6,1-diyl))dicarbamate, N'1,N'2 2-dibenzoyldocosa-10,12-diynedihydrazide, tert-butyl 2-(pentacosa-10,12-diynediyl)hydrazine-1-carboxylate, N1,N2 2-dicyclodecyldocosa-10,12-diynediamide and di-tert-butyl (((docosa-10,12-diynediyl)bis(azanediyl)bis(hexane-6,1-diyl))dicarbamate.

[0074] Keto acid compounds The color-forming compound may be a keto acid compound.

[0075] The term "keto acid compound" refers to a compound having a carboxylic acid group and a ketone group. In some instances, the ketone group is hydrated.

[0076] The color-forming compound has the formula (V):

[0077] [ka] and In the formula, X 1a , X 2a , and X 3a is independently selected from C, N, B and S; The two R groups may be the same or different and are independently: hydrogen, C 1~18 Alkyl; optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C6~12 Aryl;Halogen;-NO2;-CF3;-OR 3- ;-NR 3 2;-CN;-SR 3 ;-COR 3 ;-CO2R 3 ; and -CONR 3 2; wherein R 3 is an alkali metal; hydrogen; C 1~18 Alkyl; and optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C 6~12 aryl; or both R groups together with the nitrogen atom to which they are attached form a cyclic amino group, the cyclic amino group optionally being selected from C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 It is substituted with alkyl.

[0078] A may be the same as or different from B′ (defined below) and is independently: hydrogen; 1~18 Alkyl; optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C 6~12 Aryl;Heterocycle;Heteroaryl;Halogen;-NO2;-CF3;-OR 3 ;-NR 3 2;-CN;-SR 3 ;-COR 3 ;-CO2R 3 ;-CONR 3 2; wherein R 3 is an alkali metal; hydrogen; C 1~18 Alkyl; and optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C 6~12 aryl; R 1 teeth,

[0079] [ka] wherein X is selected from the group consisting of 1b , X 2b , X 3b and X 4b is independently selected from C, N, B and S; B' is the same as or different from A and is independently hydrogen; C 1~18 Alkyl; optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C 6~12 Aryl;Heterocycle;Heteroaryl;Halogen;-NO2;-CF3;-OR 3 ;-NR 3 2;-CN:-SR 3 ;-COR 3 ;-CO2R 3 ;-CONR 3 2; wherein R 3 is an alkali metal; hydrogen; C 1~18 Alkyl; and optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, C 1~18 C substituted with alkyl, hydroxyl (-OH), or -NR2 6~12 aryl, where R is as defined above.

[0080] It is understood that A and B' may comprise a substituent at one position on the benzene ring to which each of A and B' is associated, or A and B' may comprise multiple independently selected substituents at any of the available positions on the benzene ring to which each of A and B' is associated. For example, the benzene ring to which B' is associated may be substituted with a single substituent or up to four independently selected substituents.

[0081] Preferably, the keto acid compound has the formula (VI):

[0082] [ka] wherein X is selected from the group consisting of 1a , X2a , X 3a , X 1b , X 2b , X 3b and X 4b , R, A and B' are as described above for formula (V).

[0083] Preferably, the keto acid compound has the formula (VII):

[0084] [ka] wherein R is as described above for formula (V). Preferably, the two R groups are the same and C 1~18 Alkyl; optionally C 1~18 Alkoxy, -CN, -CF3, -NO2, halogen, or C 1~18 Alkyl-substituted C 6~12 More preferably, the two R groups are the same and are selected from C 1~18 Alkyl, more preferably C 1~6 Preferably, B' is independently selected from hydrogen; -NO2 and halogen, more preferably hydrogen and chlorine, and most preferably hydrogen.

[0085] Preferably, the keto acid compound is selected from 2-(4-(dimethylamino)-2-hydroxybenzoyl)benzoic acid, 2-(4-(dibutylamino)-2-hydroxybenzoyl)benzoic acid, 2-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid, and 2,3,4,5-tetrachloro-6-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid. More preferably, the keto acid compound is selected from 2-(4-(dimethylamino)-2-hydroxybenzoyl)benzoic acid, 2-(4-(dibutylamino)-2-hydroxybenzoyl)benzoic acid, and 2-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid.

[0086] The keto acid compounds of formulae (V)-(VII) are commercially available; for example, they can be purchased from Chameleon Speciality Chemicals Limited.

[0087] In one embodiment, the keto acid compound may be in the form of a "dimer", whereby B' is -COR 3 group (in the formula, R 3 are hydrogen, so that the benzene ring carries two carboxyl groups), and independently -COR 3 group, wherein R 3 is a C substituted with hydroxyl (-OH) and NR2 6~12 Note that R is as described above for formula (V). 3 group (in the formula, R 3 is hydrogen, so the benzene ring carries two carboxyl groups) is X 2b Located in -COR 3 The base is X 3b is located.

[0088] When the color-forming compound is a leuco dye or a keto acid compound, the color-forming compound is associated with an acid generator in the composition.

[0089] Without being bound by theory, it is believed that the acid generator and the leuco dye or keto acid compound interact to achieve color formation. The acid generator is present in the composition to promote a change in pH by generating an acid upon application of appropriate near or mid-infrared radiation. This acid generation promotes color formation by the color-forming compound. By "acid" is meant any molecular entity or chemical species that can donate a hydrogen (proton) or form a covalent bond with an electron pair. Additionally, one skilled in the art will appreciate that the transfer of heat from the heat transfer agent is to both the acid generator and the color-forming compound.

[0090] Suitable acid generators include any suitable commercially available or chemically synthesized acid generators.Suitable acid generators include, but are not limited to, borobenzilate and amine salts of 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-wide), as well as thermal acid generators (TAGs) including those based on 4-hydroxy-4'-isopropoxydiphenylsulfone, (2,4-dihydroxyphenyl)phenylmethanone, 3-(3-tosylureido)phenyl-4-methylbenzenesulfonate, 1,1,1-tris(4-hydroxyphenyl)ethane, propyl-3,4,5-trihydroxybenzoate and 4,4'-methanediyldiphenol.

[0091] It will be appreciated by those skilled in the art that the choice of acid generator will depend on the particular leuco dye or keto acid compound utilized in the composition.

[0092] The composition according to the first, second or third aspect of the invention may comprise a plurality of colour forming compounds.

[0093] When more than one color-forming compound is present in the composition, it is understood that the color-forming compounds will be different. By "different" with respect to the color-forming compounds, it is meant that the color-forming compounds are selected from different classes of color-forming compounds, such as leuco dyes, oxoanions of polyvalent metals, diacetylene compounds, or ketoacid compounds, as defined above, or are selected to be different compounds within the same class of color-forming compounds (e.g., two different leuco dyes).

[0094] It will be understood by those skilled in the art that when multiple color forming compounds are present in a composition, the two color forming compounds cannot both be selected to have an acid generator associated with them, i.e., the compound can only contain one acid generator. When two color forming compounds are present, they are selected such that only one requires an acid generator, or in certain instances, the acid generator associated with one of the two color forming compounds also interacts with the other of the two color forming compounds.

[0095] It will be understood that when a combination of color forming compounds is present in the composition, the colors of the color forming compounds will typically be different colors.

[0096] The heat transfer agent may be any suitable compound capable of facilitating the transfer of heat from the near infrared absorbing compound to the color forming compound of the composition.

[0097] Surprisingly and advantageously, the improved color formation demonstrated by the compositions of the present invention can be obtained by the selection of a particular heat transfer agent. This is embodied by the third aspect of the present invention, but is also applicable to the first and second aspects. The heat transfer agent may be a metal oxide, metal pyrophosphate, or metal phosphate of the following metals: iron, aluminum, zirconium, titanium, or combinations 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 combinations thereof. It will be understood by those skilled in the art that reference to a metal oxide, metal pyrophosphate, or metal phosphate is to be interpreted as including any hydrate of the given metal oxide, metal pyrophosphate, or metal phosphate. The heat transfer agent can be selected from: iron (III) pyrophosphate hydrate, aluminum zinc oxide, zirconium (IV) oxide, aluminum oxide, iron phosphate dihydrate, and titanium dioxide. More preferably, the heat transfer agent is selected from: iron(III) pyrophosphate hydrate, aluminum zinc oxide, 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, aluminum oxide, and titanium dioxide. Even more preferably, the heat transfer agent is selected from aluminum zinc oxide, zirconium(IV) oxide, aluminum oxide, zinc oxide and titanium dioxide. Most preferably, the heat transfer agent is zirconium(IV) oxide.

[0098] It will be appreciated by those skilled in the art that the heat transfer agent requires a high melting temperature (melting point) or thermal decomposition temperature. Preferably, the heat transfer agent has a higher melting temperature or thermal decomposition temperature than the color forming compound. It will be appreciated by those skilled in the art that the heat transfer agent may be selected depending on the color forming compound and the particular substrate utilized. Preferably, the heat transfer agent has a melting temperature or thermal decomposition temperature of 300°C or higher, such as 500°C or higher, or 1,000°C or higher, or even 2,000°C or higher. Preferably, the color forming compound has a melting temperature or thermal decomposition temperature of 50-300°C, such as 100-300°C.

[0099] The melting temperature (melting point) or thermal decomposition temperature can be measured using any suitable method. Suitable measurement methods are well known to those skilled in the art. Preferably, the melting temperature or thermal decomposition temperature is measured using a melting point tube (capillary method) or differential scanning calorimetry (DSC).

[0100] Further, it will be appreciated by those skilled in the art that the heat transfer agent requires a high heat capacity. "Heat capacity" refers to the amount of heat supplied to a given mass of material to produce a unit change in temperature. Preferably, the heat transfer agent has a heat capacity greater than the binder and carrier components utilized in the composition. Preferably, the heat transfer agent has a heat capacity of 250 J / Kg.K (Joules per Kg Kelvin) or more, more preferably 50 to 1,000 J / Kg.K, for example 250 to 800 J / Kg.K. Most preferably, the heat transfer agent has a heat capacity of 400 to 600 J / Kg.K.

[0101] The heat transfer agent may be white, off-white or colorless. In some examples, the heat transfer agent may exhibit a light, bright or low color. Preferably, the heat transfer agent is white, off-white or colorless. This means that the heat transfer agent has only a small effect on the color of the composition, and thus the background color of the composition (the portion of the composition that was not exposed to radiation) has a reduced or low color after the composition is applied to the substrate before exposure to near or mid-infrared radiation, as well as after the near or mid-infrared radiation is applied to a particular portion of the composition. This reduced or low colored background color contrasts with the intense color of the color or image formed on the substrate by the application of near or mid-infrared radiation. The impact of the heat transfer agent on the background color of the composition can be demonstrated by measuring the ΔE value using an X-Rite eXact or SpectroEye spectrophotometer. For example, ΔE is the ratio of the L of the composition after application to the substrate to the L of the composition. * a * b * Measurement and reference white tile L * a * b * It can be calculated from measurements, and further details are provided in the detailed Examples section below.

[0102] The heat transfer agent is present in the composition of the present invention as solid particles, particularly solid particles dispersed throughout the composition. The heat transfer agent is introduced into the composition as solid particles and remains dispersed in the composition as said solid particles. The advantageous transfer of heat from the near infrared absorbing compound of the composition of the present invention to the color-forming compound is achieved by the transfer of heat in a network of individual solid particles of the heat transfer agent present in the composition. The solid particles of the heat transfer agent are dispersed throughout the composition. Specifically, the solid particles of the heat transfer agent are dispersed throughout one or more binder and carrier components of the composition, and thus can transfer heat from the near infrared absorbing compound to the color-forming compound of the composition. Those skilled in the art will understand that such heat transfer agents cannot be facilitated by ionic, dissociated or dissolved forms of materials in the composition, such as ionic, dissociated or dissolved materials in the liquid, vapor or gas phase.

[0103] Preferably, the heat transfer agent has a D50 particle size distribution value of 5 μm or less. The D50 particle size distribution is the average diameter or the mean value of the particle size distribution, i.e., the particle size at 50% of the cumulative distribution. More preferably, the heat transfer agent has a D50 particle size distribution value of 0.1-4 μm, such as 0.1-3 μm, most preferably 0.5-2 μm.

[0104] The D50 particle size distribution is measured using a Malvern Mastersizer according to ISO standard 13320:2009.

[0105] Preferably, the heat transfer agent has a thickness of 3 to 25 m. 2 More preferably, the heat transfer agent has a surface area of ​​10 to 25 m 2 / g, most preferably 15 to 25m 2 / g surface area.

[0106] Surface area is measured using a Malvern Mastersizer according to ISO standard 13320:2009 and surface area is calculated from particle size distribution data.

[0107] It has further surprisingly and advantageously been discovered that the improved color formation demonstrated by the compositions of the present invention can result from the selection of a particular ratio of near infrared absorbing compound and heat transfer agent in the composition, which is embodied by the first aspect of the present invention, but is also applicable to the second and third aspects.

[0108] The ratio of the near infrared absorbing compound to the heat transfer agent in the composition may be 1:1 to 1:100. Preferably, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1 to 1:50, such as 1:1 to 1:20. More preferably, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1.5 to 1:18. More preferably, the ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1.7 to 1:15, such as 1:4 to 1:15 or even 1:5 to 1:15. It will be understood by those skilled in the art that such a ratio allows efficient transfer of heat from the near infrared absorbing compound to the color-forming compound of the composition via the heat transfer agent.

[0109] It has further surprisingly and advantageously been discovered that the improved color formation demonstrated by the compositions of the present invention can result from the selection of specific amounts of near infrared absorbing compound and heat transfer agent in the composition, which is embodied by the second aspect of the present invention, but is also applicable to the first and third aspects.

[0110] The near infrared absorbing compound can be present in the composition in any suitable amount. Preferably, the composition comprises 0.1 to 3.5 wt %, such as 0.2 to 1.75 wt %, or even 0.5 to 1.5 wt %, such as 0.5 to 1 wt %, of the near infrared absorbing compound.

[0111] In the context of the present invention, wt% refers to percentage by weight.

[0112] The heat transfer agent may be present in the composition in any suitable amount. Preferably, the composition comprises 1 to 15 wt %, such as 2 to 12 wt %, or 2 to 10 wt %, or even 2.5 to 10 wt %, or 3 to 10 wt %, or 5 to 10 wt % of the heat transfer agent.

[0113] The NIR absorbing compound may be present in an amount of 0.1-3.5 wt% of the composition and the heat transfer agent may be present in an amount of 1-15 wt%. Preferably, the NIR absorbing compound may be present in an amount of 0.2-1.75 wt% of the composition and the heat transfer agent may be present in an amount of 2-12 wt%, such as 2-10 wt%. More preferably, the NIR absorbing compound may be present in an amount of 0.5-1.5 wt%, such as 0.5-1 wt%, and the heat transfer agent may be present in an amount of 2-10 wt%, such as 2.5-10 wt%, or 3-10 wt%, or 5-10 wt%.

[0114] The colour forming compound may be present in the composition in any suitable amount. Preferably, the composition comprises 1 to 40 wt %, such as 5 to 25 wt %, or even 5 to 15 wt % of the colour forming compound.

[0115] If desired, the acid generator associated with the colour forming compound may be present in the composition in any suitable amount. Preferably, the composition comprises from 3 to 35 wt %, for example from 10 to 20 wt %, of the acid generator.

[0116] The composition may further comprise one or more binder and carrier components. Conventionally, only insulators, such as insulating polymers, having high glass transition temperature (Tg) and high minimum film-forming temperature (MFFT) could be used as binder and carrier components. However, it has been surprisingly and advantageously discovered that a wider range of binder and carrier components can be used in the composition of the present invention, including binder and carrier components having lower glass transition temperature (Tg) and / or lower minimum film-forming temperature (MFFT). This allows the composition of the present invention to be used on a wider range of substrates, including heat-sensitive substrates such as heat-sensitive polymer foils and films.

[0117] The binder or carrier components can have any suitable glass transition temperature (Tg). It will be understood by those skilled in the art that the selection of the binder or carrier components will depend at least on the substrate to which the composition will be applied.

[0118] The binder or carrier components may have a Tg of −60 to 120° C., such as −10 to 120° C., or 20 to 115° C., or even 40 to 110° C. Glass transition temperatures within this range are suitable for substrates other than polymer foils and films, such as paper substrates.

[0119] The binder and carrier component(s) may have a Tg of −60 to 40° C., such as −55 to 30° C., or even −50 to 25° C. Glass transition temperatures within this range are suitable for polymeric foil and film substrates, including heat sensitive polymeric foil and film substrates.

[0120] The Tg of one or more binder and carrier components can be measured by any suitable method. The method of measuring Tg will be well known to those skilled in the art. In this specification, Tg is measured using differential scanning calorimetry (DSC). Typically, this is in accordance with ASTM D3418 and / or ASTM E1356 and / or ISO11357.

[0121] The binder or carrier components may have any suitable minimum film forming temperature (MFFT). It will be understood by those skilled in the art that the selection of the binder or carrier components will depend at least on the substrate to which the composition will be applied.

[0122] The binder or carrier components may have a MFFT of −10 to 120° C., such as −10 to 115° C., or even 40 to 110° C. A minimum film-forming temperature within this range is suitable for substrates other than polymer foils and films, such as paper substrates.

[0123] The binder or carrier components may have a MFFT of −10 to 40° C., such as −10 to 35° C., or −5 to 30° C., or even −5 to 25° C. Minimum film-forming temperatures within this range are suitable for polymeric foil and film substrates, including heat-sensitive polymeric foil and film substrates.

[0124] MFFT can be measured by any suitable method. Methods for measuring MFFT will be known to those skilled in the art. Herein, MFFT is measured according to ISO2115:1996.

[0125] Examples of suitable binder or carrier components include, but are not limited to, polymeric binders such as acrylic polymers, styrene polymers, styrene-acrylic copolymers and their hydrogenated products; vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride and polyvinyl butyral; polyolefins and their hydrogenated or epoxidized products; aldehyde-containing polymers; epoxide-containing polymers; polyamides; polyesters; polyurethanes; sulfone-containing polymers; natural products and their derivatives; cellulosic polymers such as nitrocellulose; and combinations thereof. The binder or carrier components can be selected from, but are not limited to, polymeric binders such as acrylic polymers and styrene polymers; vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride and polyvinyl butyral; polyolefins and their hydrogenated or epoxidized products; aldehyde-containing polymers; epoxide-containing polymers; polyamides; polyesters; polyurethanes; sulfone-containing polymers; natural products and their derivatives; cellulosic polymers such as nitrocellulose; and combinations thereof.

[0126] Preferably, the one or more binder and carrier components are selected from acrylic polymers, styrene polymers, styrene-acrylic copolymers, vinyl polymers (such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride and polyvinyl butyral); polyamides; polyurethanes; and cellulosic polymers such as nitrocellulose; and combinations thereof. More preferably, the one or more binder and carrier components are selected from styrene-acrylic copolymers, cellulosic polymers (such as nitrocellulose), and polyurethanes, and combinations thereof.

[0127] The binder and carrier component(s) may be present in the composition in any suitable amount. Preferably, the composition comprises 5-70 wt%, such as 6-70 wt% or 7-65 wt%, or even 10-65 wt%, or 10-40 wt% of the binder and carrier component(s).

[0128] The composition according to the first aspect of the present invention may further comprise a curable compound. Suitable curable compounds will be known to those skilled in the art. Examples of suitable curable compounds include, but are not limited to, any commercially available monomer, oligomer, mixture of monomer and oligomer, or photoinitiator. The curable compound may be present in the composition in any suitable amount.

[0129] The composition may further comprise an additive or a combination of additives. Suitable additives will be 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; 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 deviscosifiers; moisturizers; adhesion promoters; acid or base scavengers; retarders; defoamers; antifoaming agents; and combinations thereof. Preferably, the composition comprises 0.1-10 wt%, for example 0.25-7.5 wt%, more preferably 0.5-5 wt% of additives or combinations thereof.

[0130] The composition may further comprise a solvent. The composition may comprise a single solvent or a mixture of solvents. The solvent may comprise water, an organic solvent, a mixture of water and an organic solvent, or a mixture of organic solvents. Suitable organic solvents include, but are not limited to, 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, 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, ethylene glycol monobutyl ether; and combinations thereof. Those skilled in the art can determine the appropriate solvent for use in the compositions according to the first, second, and third aspects of the present invention, particularly based on the color-forming compounds present in the composition. Typically, when the color-forming compound is an oxoanion of a polyvalent metal, the solvent may be water-based (containing only water and no organic solvents) or solvent-based (containing only organic solvents and no water). Typically, when the color-forming compound is a leuco dye, the solvent is water-based. Preferably, the solvent is present in the composition in an amount of 0.1 to 60 wt%, such as 10 to 50 wt%, or even 30 to 45 wt%. The amount of solvent is understood to include all solvents present in the composition, i.e., any solvents of the component materials used to form the composition.

[0131] It will be understood by those skilled in the art that the printing viscosity of the compositions according to the invention will vary depending on the printing application. For water and solvent based printing, the compositions of the invention may have a printing viscosity of 100-600 cP (0.1-0.6 Pascal seconds). For UV flexographic printing, the compositions of the invention may have a printing viscosity of 6000-17,000 cP (6-71 Pascal seconds). For UV offset printing, the compositions of the invention may have a printing viscosity of 90,000-200,000 cP (90-200 Pascal seconds). The printing viscosity is measured using a Brookfield DV2T viscometer (No. 3 spindle (RV spindle set), speed 60 rpm, 22° C.). This printing viscosity is the viscosity of the composition when it is ready for application to the substrate.

[0132] The compositions of the present invention preferably include, in addition to the heat transfer agent, color forming compound, and near infrared absorbing compound, one or more carrier or binder components, an additive or combination of additives, and a solvent or combination of solvents.

[0133] The composition of the present invention is a radiation-responsive composition, such as a laser-responsive composition. The composition of the present invention is further suitable as an ink composition. The composition of the present invention is suitable for forming colors and single- or multi-color images on a substrate.

[0134] The composition according to the first, second or third aspect of the invention can be applied to any suitable substrate, it being understood that the contents of the composition will likely vary depending on the substrate to which the composition is applied.

[0135] Thus, according to a fourth aspect of the invention there is provided a substrate comprising a composition according to the first aspect of the invention applied onto the substrate.

[0136] According to a fifth aspect of the invention there is provided a substrate comprising the composition of the second aspect of the invention applied onto the substrate.

[0137] According to a sixth aspect of the invention there is provided a substrate comprising the composition of the third aspect of the invention applied onto the substrate.

[0138] As mentioned above, it has been surprisingly and advantageously discovered that the composition according to the first, second or third aspect of the present invention can be applied to a heat-sensitive substrate. By "heat-sensitive substrate" is meant any substrate having a melting or thermal decomposition temperature of 200°C or less, such as paper, or a polymeric film or foil substrate having a melting or thermal decomposition temperature of 200°C or less. Previously, without a heat transfer agent present as solid particles dispersed throughout the composition, the heat-sensitive substrate could not be utilized because the binder or carrier component would have softened or melted upon absorbing excess heat from the near infrared absorbing compound, and therefore the excess heat would have been transferred to the heat-sensitive substrate. The composition according to the present invention substantially retains and utilizes heat in a favorable and constructive manner, and does not transfer it to the substrate in an unfavorable and destructive manner, and thus can be applied to a heat-sensitive substrate.

[0139] Examples of suitable substrates to which the composition may be applied include, but are not limited to, polymers and recycled polymeric materials, such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), cast polypropylene (CPP), polyamides (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastics; metals and metal foils such as tinplate; textiles; paper; corrugated paperboard; cardboard, and equivalent recycled analogs, or combinations thereof; ceramics; foodstuffs and pharmaceuticals; or combinations thereof, such as polymer-ruled paper or polymer-impregnated paper. Polymers and recycled polymeric materials may be in the form of polymer foil or film substrates.

[0140] Suitable substrates include multi-layer substrate structures formed from the materials and substrates listed above.For example, multi-layer substrate structures can include paper substrates that are joined to polymer foil or film substrates, such as polypropylene films that form laminated substrates.Other multi-layer substrate structures include two or more polymer foil or film substrates, in which the composition is sandwiched between or applied to the outside of either the polymer foil or film substrates and joined.It will be understood by those skilled in the art that the constituent substrates of the multi-layer substrate structure are joined by adhesive.

[0141] Preferably, the substrate to which the composition is applied is a paper substrate or a polymer foil or film substrate.Preferably, the polymer film or foil substrate is selected from polypropylene (PP), polyethylene (PE) or polyethylene terephthalate (PET).More preferably, the polymer film or foil substrate is selected from polypropylene (PP) and polyethylene (PE).

[0142] The substrate to which the composition is applied may have a thickness of from 12 μm to 12 mm, for example from 12 μm to 1 mm, or from 20 to 500 μm, or even from 30 to 350 μm.

[0143] When the substrate is a paper substrate, the substrate to which the composition is applied may have a weight per unit weight (gsm) of from 50 to 500 gsm, for example from 60 to 250 gsm, including from 80 to 200 gsm.

[0144] Those skilled in the art will understand that the substrate that the composition is applied to can itself be applied to further substrates.Examples of further substrates include, but are not limited to, polymers and recycled polymeric materials, such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) (such as nylon), polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastics; metals and metal foils, such as tinplate; textiles; paper; corrugated paperboard, cardboard, and equivalent recycled analogs, or combinations thereof; ceramics; foodstuffs and pharmaceuticals; or combinations thereof, such as polymeric lined paper.Suitable substrates include multilayer structures formed from the materials and substrates listed above.Polymers and recycled polymeric materials can be in the form of polymer foil or film substrates.

[0145] The composition according to the first, second or third aspect of the invention, or the substrate to which the composition has been applied according to the fourth, fifth or sixth aspect of the invention, may be suitable for end uses as signage (adhesive or wraparound) and / or in everyday consumer goods; packaging such as disposable packaging including food and hot or cold beverage containers; hygiene and personal care product packaging such as shampoo containers; cosmetic packaging; decorative metalware; blister pack packaging; laminated pouches; medical and diagnostic devices and related packaging; and signage.

[0146] Preferably, the substrate comprises an adhesive layer. It should be understood that this adhesive layer serves to attach the substrate to a further substrate or any other material, and is therefore on the outer surface of the substrate. The adhesive layer may cover all, substantially all, or a portion of the surface of the outer surface of the substrate. When the composition is applied to the substrate, the adhesive layer is preferably on the outer surface of the substrate other than the portion where the composition is applied.

[0147] It will be appreciated that the substrate may comprise a single layer or multiple layers of the composition according to the first, second or third aspect of the invention applied to the substrate.

[0148] It should be understood that the substrate may further comprise one or more additional layers applied thereto to form a multi-layer structure. The multi-layer structure may comprise a substrate having a plurality of discontinuous layers applied thereto. The plurality of discontinuous layers may comprise a composition according to the first, second or third aspect of the present invention, and one or more additional layers. Suitable additional layers may be selected from, but are not limited to, thermal insulation layers, protective layers, primer layers, adhesion promoting layers, barrier layers, and radiation blocking layers (such as ultraviolet blocking layers), light quenching layers, hindered amine light stabilizers, and combinations thereof.

[0149] Preferably, the multilayer structure is composed of a substrate to which the following have been applied in this order: a primer layer, a layer formed of a composition according to the first, second or third aspect of the present invention, and a protective layer (such as an overvarnish layer). As described above, it will be understood by those skilled in the art that the binder and carrier components with low Tg and low MFFT allow a heat-sensitive substrate to be utilized in the multilayer structure. In addition, the binder and carrier components with low Tg and low MFFT also advantageously allow one or more additional heat-sensitive layers, such as a primer layer and a protective layer, to be utilized in the multilayer structure. In the multilayer structure, the composition of the present invention allows the absorption of heat from near infrared radiation to be retained in the layer of the composition according to the first, second or third aspect of the present invention, thus allowing one or more additional heat-sensitive layers and heat-sensitive substrates to be utilized. This increases the range of applications of the multilayer structure comprising the composition according to the present invention. In said multilayer structure, the substrate can be selected from those listed above, including multilayer substrate structures.

[0150] One or more additional layers of the multilayer structure may also include a layer containing a different color-forming compound. By "different color-forming compound" is meant that the color-forming compound is selected from color-forming compounds different from the color-forming compounds of the composition according to the first, second or third aspect of the invention, or that the color-forming compound is a different compound from the same color-forming compound group as the color-forming compound of the composition according to the first, second or third aspect of the invention. The color-forming compound group is a leuco dye, an oxoanion of a polyvalent metal, a diacetylene compound or a keto acid compound as defined above.

[0151] It is understood that the order of layers in the multi-layer structure may vary depending on the intended application, and it is also understood that the thickness or coat weight of each layer may vary depending on their content.

[0152] Thus, according to a seventh aspect of the invention there is provided a method of forming a substrate comprising applying a composition according to the first aspect of the invention to a substrate.

[0153] According to an eighth aspect of the invention there is provided a method of forming a substrate comprising applying to a substrate a composition according to the second aspect of the invention.

[0154] According to a ninth aspect of the present invention there is provided a method of forming a substrate comprising applying a composition according to the third aspect of the present invention to a substrate.

[0155] The composition may be applied to the substrate by any suitable method. Methods for applying the composition to the substrate will be well known to those skilled in the art. Suitable application methods include, but are not limited to, flexographic printing, gravure printing, screen printing, offset printing, and Meyer bar coating. The composition may be applied to all, substantially all, or a portion of the outer surface of the substrate.

[0156] The composition may be applied onto a substrate to any suitable coat weight, depending on both the substrate to which the composition is applied and the application method. It will be appreciated by those skilled in the art that the coat weight of the composition on the substrate will affect the intensity of the color formed. Preferably, the composition is applied to a coat weight of 0.1 to 50 gsm (grams per square meter), for example 0.1 to 25 gsm, most preferably 0.1 to 15 gsm.

[0157] Coat weight can be measured by any suitable method. Suitable measuring methods will be known to those skilled in the art. Preferably, coat weight is measured by weighing the same area of ​​the substrate with and without the composition applied, and comparing the difference between the two weights.

[0158] The composition can be applied to the substrate as a single layer or as multiple layers.

[0159] The composition may be applied to the substrate as part of multiple discontinuous layers of the multi-layer structure described above. The composition may be applied to the substrate as an undercoat or overcoat, over a primer or as a primer layer. The composition may be applied to the substrate one or more times. The composition may be applied to at least a portion or all of the outer surface of the substrate.

[0160] It should be understood that one or more of the additional layers described above in relation to the substrate may be applied to the substrate in the same manner as described herein in relation to the composition.

[0161] The discontinuous layers of the multi-layer structure described above can have any suitable total coat weight. Preferably, the discontinuous layers individually have a coat weight as described above in connection with the composition according to the first, second or third aspect of the present invention when applied onto a substrate. Furthermore, preferably, the discontinuous layers have a total coat weight (including all layers) of 100 gsm (grams per square meter) or less, more preferably 50 gsm or less, and most preferably 30 gsm or less. Those skilled in the art will appreciate that the total coat weight of the discontinuous layers will depend on the layer formation and substrate.

[0162] After formulation, when applied to a substrate, and before application of near infrared or mid infrared radiation, the composition according to the first, second and third aspects of the present invention (as well as utilized in all other aspects) may be white, off-white or colorless. In some examples, the composition may exhibit a light, bright or low color. This light, bright or low color may be caused by the presence of either a near infrared absorbing compound, a color-forming compound or a heat transfer agent, but typically by a near infrared absorbing compound. It will be understood that, when displayed, this light, bright or low color is a color that is visually significantly weaker than the color formed upon application of near infrared or mid infrared radiation, and thus, upon application of near infrared or mid infrared radiation, the formation of a strong contrast color and / or image is achieved. It will be further understood that the background of the composition, i.e., the portion of the composition that is not exposed to near infrared or mid infrared radiation, remains white, off-white or colorless, or in some examples, exhibits a light, low or light color as described above.

[0163] The compositions according to the first, second or third aspects of the invention (and utilised in all other aspects) may be clear, transparent or translucent when formulated, when applied to the substrate and prior to application of near infrared or mid infrared radiation.

[0164] Application of the composition to a substrate allows for the formation of colors and images on the substrate.

[0165] Thus, according to a tenth aspect of the present invention there is provided a method of forming a colour on a substrate comprising a composition according to the first aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to cause the formation of a colour on the substrate.

[0166] According to an eleventh aspect of the present invention there is provided a method of forming a colour on a substrate comprising a composition according to the second aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to cause the formation of a colour on the substrate.

[0167] According to a twelfth aspect of the present invention there is provided a method of forming a colour on a substrate comprising a composition according to the third aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to cause the formation of a colour on the substrate.

[0168] According to a thirteenth aspect of the present invention there is provided a method of forming an image on a substrate comprising a composition according to the first aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0169] According to a fourteenth aspect of the present invention there is provided a method of forming an image on a substrate comprising a composition according to the second aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0170] According to a fifteenth aspect of the present invention there is provided a method of forming an image on a substrate comprising a composition according to the third aspect of the present invention applied onto the substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

[0171] Terms used herein, such as the term "color", refer to the colors and hues of the visible light color spectrum, i.e., red, orange, yellow, blue, green and violet, in addition to black, brown, turquoise, purple, pink, cyan, and magenta, and mixtures thereof. Both primary and secondary colors are included. In the context of the present invention, the terms may also be used to describe different shades of each color of the visible light color spectrum, in addition to magenta, cyan, pink, purple, turquoise, brown, and black.

[0172] The term "image" incorporates, but is not limited to, codes and marks, graphics, drawings, photographs, symbols, and text, such as logos, machine-readable linear barcodes, 2D Datamatrix codes, QR codes, and Digimarc codes. The term further incorporates both monochromatic and multi-color images. In the context of the present invention, both monochromatic and multi-color images are understood to be the manipulation of a composition that includes a color-forming compound that promotes the formation of an image. The formed image is human and / or machine readable and can be used for purposes of coding and marking, tracking and tracing tagging, and end-stage customization or personalization. Codes can be composed of alphanumeric text or symbol fonts to indicate, for example, expiration dates and / or batch or lot codes. Codes can be graphics and can be scanned or verified, for example, with devices such as barcode scanners, locators, or with a smartphone camera or app. In the context of the present invention, images are contrast images. By "contrast image" it is meant that the image formed by the composition on the substrate is clear and easily distinguishable from the background of the composition, i.e., the portion of the composition that has not been exposed to near or mid-infrared radiation, or the color of the substrate if viewed through the composition after application to the substrate.

[0173] If the color formed is black or the color or shade or tone of the image formed (including grayscale) is black, the optical density of the color or image can be evaluated by measuring the optical density black (ODB) value. If the color formed is red or the color or shade or tone of the image formed is red, the optical density of the color or image can be evaluated by measuring the optical density magenta (ODM) value. If the color formed is blue or the color or shade or tone of the image formed is blue, the optical density of the color or image can be evaluated by measuring the optical density cyan (ODC) value. If the color formed is yellow or the color or shade or tone of the image formed is yellow, the optical density of the color or image can be evaluated by measuring the optical density yellow (ODY) value. In relation to the ODB, ODM, ODC and ODY values, the higher the value, the darker the respective color formed: black, magenta, cyan or yellow.

[0174] The ODB, ODM, ODC and ODY values ​​quantify the optical density on a black, magenta, cyan or yellow color scale from low to high, where the ODB, ODM, ODC and ODY measurements can be made using a standard instrument densitometer and an X-Rite eXact or SpectroEye or TechKon SpectroDens spectrophotometer.

[0175] The difference ΔODB, ΔODM, ΔODC or ΔODY in the measured optical density between the image (ODB, ODM, ODC or ODY value) and the unimaged composition background, i.e., the portion of the composition on the substrate that has not been exposed to radiation (background ODB, ODM, ODC or ODY), can also be measured.

[0176] In the context of the present invention, efficient formation of a color or image is demonstrated by measurement of an ODB, ODM, ODC or ODY value of 1.05 or greater, preferably 1.1 or greater. Such values ​​demonstrate good optical density, i.e., the formation of a strong (dark) color or a dense, intensely colored image with good contrast against the background of the composition.

[0177] Typically, the color or image formed is retained under ambient conditions for at least 3 days, preferably at least 4 days, more preferably at least 1 week or even at least 2 weeks, and most preferably at least 2 months. Terms used herein such as "ambient conditions" refer to the normal range of conditions of the surrounding environment to which the color-forming compound is exposed, i.e., the range of temperature, pressure and atmospheric conditions to which the compound is exposed during use, storage and otherwise. This includes electromagnetic radiation of X-rays, solar radiation including ultraviolet (UV) and infrared (IR) radiation.

[0178] Typically, ambient conditions include a temperature of 10-35° C., a pressure of 20-100 kPa, and the environment is typically an oxygen-containing atmosphere.

[0179] Terms as used herein such as "monochromatic image" or "single-colour image" refer to an image that is human and / or machine readable and has a single colour visible to the human eye. In the context of the present invention, the background portion of the composition according to the first, second and third aspects of the invention (as well as for use in all other aspects) may form part of the monochromatic image.

[0180] Terms used herein such as "multicolour image" refer to a human and / or machine readable image having more than one colour, i.e. more than one image visible to the human eye. In the context of the present invention, the background portion of the composition according to the first, second and third aspects of the invention (as well as used in all other aspects) may form part of a multicolour image.

[0181] Terms used herein such as "radiation" refer to energy in the form of waves or particles, particularly electromagnetic radiation such as ultraviolet (UV), visible light, near infrared (NIR) and infrared (IR) particle radiation, e.g. alpha (α) radiation, beta (β) radiation, neutron radiation and plasma. The wavelength ranges of different regions of the electromagnetic spectrum are known to those skilled in the art. For completeness, the term "near infrared" refers to radiation in the near infrared region of the electromagnetic spectrum, having a wavelength of 780 nm to 2500 nm, preferably 780 nm to 1600 nm. Typically, near infrared is applied at wavelengths of 780 nm to 1600 nm when using commercially available fiber lasers. The term "mid infrared" refers to radiation in the mid infrared region of the electromagnetic spectrum, having a wavelength of 2500 nm to 50000 nm, preferably 9000 to 12000 nm, or 9300 nm, 9600 nm, 10200 nm or 10600 nm, or more preferably 10600 nm. Typically, mid-infrared radiation is applied using commercially available CO2 lasers at wavelengths of 9000 to 12000 nm, for example 9300 nm, 9600 nm, 10200 nm or 10600 nm, preferably 10600 nm.

[0182] As used herein, terms such as "laser light source" refer to any suitable commercially available or non-commercially available laser light source. Suitable examples include, but are not limited to, a fiber laser, a fiber-coupled laser diode array, a CO2 laser, a laser diode array, or a direct diode laser for providing radiation, including near-infrared or mid-infrared radiation.

[0183] The composition on the substrate is exposed to either near infrared radiation or mid-infrared radiation. The composition on the substrate is exposed to near infrared radiation having a wavelength of 780 to 1600 nm or mid-infrared radiation having a wavelength of 9000 to 12,000 nm. Preferably, the composition is exposed to near infrared radiation having a wavelength of 780 to 1600 nm or mid-infrared radiation having a wavelength of 9300, 9600, 10200 or 10600 nm. Preferably, the composition is exposed to near infrared radiation having a wavelength of 780 to 1600 nm or mid-infrared radiation having a wavelength of 10600 nm. More preferably, the composition is exposed to near infrared radiation. More preferably, the composition is exposed to near infrared radiation having a wavelength of 780 to 1600 nm.

[0184] Near infrared or mid-infrared radiation may be applied to the substrate to develop color throughout the composition or the color-forming compound may develop color selectively at localized locations of the composition to form a desired image. Preferably, color is developed selectively at different localized locations of the composition on the substrate.

[0185] It will be appreciated by those skilled in the art that when color-forming compounds capable of forming multiple colors (e.g., diacetylene compounds) are utilized in a composition according to the first, second or third aspect of the invention; when combinations of color-forming compounds are present in a composition according to the first, second or third aspect of the invention; or when color-forming compounds different from those in a composition according to the first, second or third aspect of the invention are present in one or more additional layers of the multi-layer structure described above, a multi-color image may be formed. The color of each color-forming compound may be selectively developed at a local location in the composition.

[0186] Near infrared or mid-infrared radiation can be applied to the composition using any suitable means. Suitable means include laser excitation by applying near infrared or mid-infrared radiation to the composition and thus to the color-forming compound by a laser source. Near infrared radiation is typically applied using a NIR fiber diode laser. Mid-infrared radiation is typically applied using a CO2 laser. Those skilled in the art will understand that near infrared or mid-infrared radiation can be applied to the composition at localized locations to selectively develop the color of the color-forming compound at these localized locations of the composition. These localized locations may overlap with each other. Those skilled in the art will understand that alternatively, near infrared or mid-infrared radiation can be applied to the composition on or within the substrate by flood lighting, meaning that the entire composition is saturated with radiation. This can be done using lamps or bulbs such as IR lamps, diode bars, or LEDs. Those skilled in the art will understand that radiation is applied to the composition for an appropriate amount of time required to promote color formation by the color-forming compound. Typically, the time required to achieve sufficient radiation depends on the power of the means used to apply radiation and the method of application (i.e., at a localized location or by flood lighting). For example, in one embodiment, near infrared or mid infrared radiation may be applied to the color forming compound for less than 120 seconds, or less than 60 seconds, such as less than 20 seconds, or even less than 10 seconds or less than 5 seconds.

[0187] The amount of near infrared or mid infrared radiation applied using a laser source to achieve color formation depends on the time for which the radiation is applied, the power (wattage) of the means used to apply the radiation, and therefore the fluence (amount of energy delivered per unit area) delivered by the laser source, i.e., J / cm 2 It should be appreciated that the frequency of the input signal can be controlled by changing

[0188] It should further be understood that when multiple color forming compounds are present, the fluence of the applied near infrared radiation required to promote color formation with different color forming compounds may be different.

[0189] When exposed to near infrared or mid infrared radiation, the color-forming compound can form any color. It should be understood that when a combination of color-forming compounds is present in the composition, the color formed by the color-forming compound will typically be different. In addition, those skilled in the art will understand that the means used to apply near infrared or mid infrared will also affect the color formed. For example, when applying near infrared or mid infrared using a laser light source, the fluence (amount of energy delivered per unit area) can affect the intensity of the color formed, and therefore the optical density. In the context of the present invention, the fluence is determined by the power (wattage) of the means used to apply near infrared radiation and the time that the near infrared radiation is applied to a specific localized location on the substrate, which can be controlled by the scanning speed of the laser or the speed of the movable stage. These two variables can be changed to change the fluence. When the fluence is low (e.g., low power and / or short exposure time), the color formed by the color-forming compound will be a weak color (low ODB, ODM, ODC or ODY value, low optical density), and when the fluence is high, the color formed by the color-forming compound will be a stronger color (higher ODB, ODM, ODC or ODY value, high optical density). When a keto acid compound is utilized as the color-forming compound, a change in fluence can also result in the color of the color-forming compound changing color. For example, a low fluence can form a yellow color, and a high fluence can form an orange or red color. In the context of the present invention, the fluence value is between 0.01 and 50 J / cm. 2 , e.g. 0.1~20J / cm 2 , and even 0.5 to 10 J / cm 2 , e.g. 0.5-5 J / cm 2 may be in the range.

[0190] As discussed above, it should be appreciated that the present invention allows for the use of low power near-infrared or mid-infrared sources to provide near-infrared or mid-infrared radiation, resulting in low fluence, and the heat transfer agent facilitates heat transfer from the near-infrared absorbing compound to the color-forming compound much more efficiently. In the context of the present invention, "low power" means less than 100 watts, e.g., less than 50 watts, per single laser source. This can be multiplied by the combination of multiple laser sources, such as laser arrays.

[0191] As mentioned above, it will be understood by those skilled in the art that additional stimuli can be applied to the composition.For example, additional stimuli such as ultraviolet light can be applied to the composition that contains a diacetylene compound as a color-forming compound to achieve the formation of an initial first color.This additional stimuli can be applied to the composition using any suitable means, including using a laser light source for application at a localized location and flood lighting for application over the entire composition as detailed above for application of near infrared light, but using a suitable light source such as a broadband UV lamp source or a UV laser for application of ultraviolet light.It should be understood that the exposure of the composition to near infrared or mid infrared light and the additional stimuli is carried out in the appropriate order required to form a desired image, and depends on the content of the composition, i.e., the color-forming compound present in the composition.It should also be understood that near infrared or mid infrared light and the additional stimuli can be applied to the same localized location of the composition.

[0192] According to a sixteenth aspect of the present invention there is provided the use of a composition according to the first aspect of the present invention in the formation of colour on a substrate by application of near or mid-infrared radiation.

[0193] According to a seventeenth aspect of the present invention there is provided the use of a composition according to the second aspect of the present invention in the formation of colour on a substrate by application of near or mid-infrared radiation.

[0194] According to an eighteenth aspect of the present invention there is provided the use of a composition according to the third aspect of the present invention in the formation of colour on a substrate by application of near or mid-infrared radiation.

[0195] According to a nineteenth aspect of the present invention there is provided the use of a composition according to the first aspect of the present invention in the formation of an image on a substrate by application of near or mid-infrared radiation.

[0196] According to a twentieth aspect of the present invention there is provided the use of a composition according to the second aspect of the present invention in the formation of an image on a substrate by application of near or mid-infrared radiation.

[0197] According to a twenty-first aspect of the present invention there is provided the use of a composition according to the third aspect of the present invention in the formation of an image on a substrate by application of near or mid-infrared radiation.

[0198] It will be understood by those skilled in the art that the near infrared or mid-infrared or additional stimuli applied to the compositions disclosed herein by laser light source or flood lighting will be applied using equipment suitable for the purpose, i.e., calculation and control of the near infrared or additional stimuli necessary to produce the desired color or image, and application to the composition on the substrate, It will be understood that the equipment will be programmed to effect the application of near infrared, mid-infrared or other stimuli to the composition in the required sequence to facilitate the formation of the image.

[0199] chemical definition The term “C 1~20 "Alkyl" refers to a straight or branched chain saturated alkyl group having 1 to 20 carbon atoms, optionally with the option "C 1~20 An "alkyl" group may contain some degree of unsaturation (partial unsaturation), i.e., it may contain one or more alkene / alkenyl moieties. 1~20 In the case of alkyl, all its subgroups, e.g. C 1~10 Alkyl, C 5~15 Alkyl, C 5~10 Alkyl, and C 1~6Alkyl is contemplated. 1~4 Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. 1~20 Alkyl group, "C 6~12 aryl", and "C 1~18 Alkoxy, halogen, and C 3~18 It may be optionally substituted with one or more functional groups, including "cycloalkyl."

[0200] The term “C 1~18 "Alkoxy" is a straight or branched chain C alkyl group attached to the rest of the molecule through an oxygen atom. 1~18 Indicates an alkyl group. Range C 1~18 When part of an alkoxy group, all its subgroups, e.g., C 1~10 Alkoxy, C 5~15 Alkoxy, C 5~10 Alkoxy, and C 1~6 Alkoxy is contemplated. 1~4 Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, and tert-butoxy. The alkoxy group may be optionally substituted with other functional groups. An alkoxy group is one selected from the group consisting of C 1~18 Alkyl group, "C 6~12 aryl", and "C 1~18 Alkoxy, halogen, and C 3~18 It may be optionally substituted with one or more functional groups, including "cycloalkyl."

[0201] The term “C 6~12 "Aryl" refers to a monocyclic or polycyclic conjugated unsaturated ring system having 6 to 12 carbon atoms. 6~12 When part of an aryl group, all its subgroups, e.g., C 6~10 Aryl, C 10~12 Aryl, and C 6~8 Aryl is contemplated. Aryl groups include monocyclic or fused ring groups such as bicyclic groups. 6~12Examples of aryl groups include phenyl, biphenyl, indenyl, naphthyl, or azulenyl. Fused rings such as indane and tetrahydronaphthalene are also C 6~12 The aryl group is optionally substituted with other functional groups. 1~18 Alkyl groups, halogens, and "C 1~18 Aryl groups may be optionally substituted with one or more functional groups, including "alkoxy." Aryl groups may be substituted with these substituents at a single position on their unsaturated ring system or at multiple positions on their unsaturated ring system.

[0202] The term “C 3~18 "Cycloalkyl" refers to a non-aromatic, saturated or partially saturated (i.e., may contain one or more alkene or alkenyl moieties) monocyclic ring system having 3 to 18 carbon atoms. 3~18 When part of cycloalkyl, all subgroups thereof, such as C 3~8 Cycloalkyl, C 5~15 Cycloalkyl, and C 5~10 Cycloalkyl is contemplated. 3~10 Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. Cycloalkyl groups may be optionally substituted with other functional groups. Cycloalkyl groups include those having the following substituents: 1~20 Alkyl group, "C 5~20 Aryl, C 1~20 Alkoxy, Hydroxyl C 1~20 Alkoxy" and "C 3~18 It may be optionally substituted with one or more functional groups, including "cycloalkyl."

[0203] The terms "unsaturated" and "partially saturated" refer to rings whose ring structure contains atoms that share more than one valence bond, i.e., the ring contains at least one multiple bond, such as a C=C, C≡C, or N=C bond. The term "fully saturated" refers to rings in which there are no multiple bonds between ring atoms.

[0204] "Optional" or "optionally" means that the subsequently described event or circumstance may occur, but does not necessarily occur, and the description includes instances in which the event or circumstance occurs and instances in which it does not occur.

[0205] "Halogen" refers to fluorine, chlorine, bromine or iodine.

[0206] The term "heterocycle" refers to a non-aromatic saturated or partially saturated monocyclic or polycyclic ring system having 4 to 18 ring atoms, but where one or more of the ring atoms are not carbon, e.g., nitrogen, sulfur, or oxygen. The ring system may be attached to the remainder of the molecule through any of the heteroatoms or carbon atoms of the ring system. Examples of heterocyclic groups include, but are not limited to, piperidinyl, morpholinyl, homomorpholinyl, azepanyl, piperazinyl, oxopiperazinyl, diazepinyl, tetrahydropyridinyl, tetrahydropyranyl, pyrrolidinyl, tetrahydrofuranyl, and dihydropyrrolyl.

[0207] The term "heteroaryl" refers to a monocyclic or polycyclic heteroaromatic group containing 5 to 18 atoms, but where one or more of the atoms are other than carbon, e.g., nitrogen, phosphorus, sulfur, or oxygen. The heteroaromatic ring may be attached to the remainder of the molecule through either a heteroatom or a carbon atom of the ring system. Examples of heteroaryl groups include, but are not limited to, furyl, pyrrolyl, thienyl, oxazolyl, isoxazolyl, oxadiazolyl, imidazolyl, oxatriazolyl, thiazolyl, isothiazolyl, tetrazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, and thiadiazolyl. In some embodiments, the heteroaryl group contains at least one ring nitrogen atom. The nitrogen atom in the heteroaryl group may be basic, as in the case of an imidazole or pyridine, or essentially non-basic, as in the case of an indole or pyrrole nitrogen. In general, the number of basic nitrogen atoms present in the heteroaryl group, including any amino substituents of the ring, will be less than 5.

[0208] The term "cyclic amino group" refers to a non-aromatic fully saturated or partially unsaturated monocyclic ring system having 4 to 18 ring atoms, one of which is nitrogen and through which the group is attached to the remainder of the molecule. In such cyclic amino groups, one or more of the remaining ring atoms may be other than carbon, such as nitrogen, sulfur or oxygen. Examples of such cyclic amino groups include piperidine (1-piperidinyl), pyrrolidine (1-pyrrolidinyl), pyrrolidone, morpholine or piperazine.

[0209] All references herein to a particular compound are intended to include the compound per se and, where appropriate, its derivatives, hydrates, solvates, complexes, isomers and tautomers.

[0210] All features contained herein may be combined with any of the above aspects, in any combination.

[0211] To better understand the present invention and to show how it may be practiced to realize embodiments thereof, the following experimental data will now be given, by way of example. EXAMPLES

[0212] For each example, unless otherwise specified, the composition is either colorless, off-white, or white after it is formulated and applied to a substrate and before it is exposed to radiation. The background of the composition, i.e., the portion not exposed to radiation, remains colorless, off-white, or white.

[0213] For each example, unless otherwise specified, a NIR fiber diode laser with a wavelength of 1070 nm is utilized, with the following fluence settings: 1.33, 1.39, 1.55, 1.61, 1.75, 2.00, 2.16, 2.37, 2.53 and 2.86 J / cm 2 2.37 and 2.53 J / cm 2 The fluence was used.

[0214] [Example 1] Compositions according to the present invention were prepared according to Table 1. All amounts are expressed as weight percentage (wt%).

[0215] [Table 1]

[0216] The composition was diluted with an additional 1:1 blend of ethanol and ethyl acetate to obtain a printing viscosity of 200 cP (0.2 Pascal seconds). The composition was gravure printed at 5 gsm onto a polypropylene film substrate.

[0217] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations to facilitate image formation.

[0218] [Comparative Example 1] Compositions without the heat transfer agent were prepared according to Table 2. All amounts are expressed as weight percentages (wt%).

[0219] [Table 2]

[0220] The composition was diluted with an additional 1:1 blend of ethanol and ethyl acetate to obtain a printing viscosity of 200 cP (0.2 Pascal seconds). The composition was gravure printed at 5 gsm onto a polypropylene film substrate.

[0221] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations to facilitate image formation.

[0222] Background coloration measurement for Example 1 and Comparative Example 1 This measurement demonstrates how the presence of the heat transfer agent in the composition according to the invention does not contribute to background coloration.

[0223] ΔE was calculated using an X-Rite SpectroEye spectrophotometer.

[0224] The L of the composition after application to the substrate but before exposure to near infrared radiation * a * b * The values ​​were measured for Example 1 and Comparative Example 1 (CIE L * a * b * Color system, L * indicates brightness, and a * indicates the red / green value, and b * (Indicates the yellow / blue value). Next, these L values ​​of Example 1 and Comparative Example 1 were * a * b * The measurements are compared with the L of a standard white tile. * a * b* Used in tandem with the measurements, the ΔE value of each of Example 1 and Comparative Example 1 was determined, i.e., the visually perceived difference between the color of the composition of Example 1 or Comparative Example 1 and a white tile. ΔE is a standard mathematical calculation that allows for the visual quantification of the difference between two colors, i.e., the background color of the composition of Example 1 or Comparative Example 1 and a white tile. The calculation is as follows:

[0225]

number

[0226] In Example 1, ΔE was calculated to be 5.48. In Comparative Example 1, ΔE was calculated to be 5.28. The difference between the two ΔE values ​​is 0.2. ΔE values ​​less than 2 are indistinguishable by the human eye. Thus, the ΔE values ​​measured for Example 1 and Comparative Example 1 demonstrate that the heat transfer agent does not significantly affect the background coloration of the composition according to the present invention.

[0227] Optical Density Black (ODB) Measurements for Example 1 and Comparative Example 1 ODB was calculated using an X-Rite SpectroEye spectrophotometer.

[0228] In Example 1, the ODB was measured to be 1.36. In Comparative Example 1, the ODB was measured to be 1.01.

[0229] An ODB value of 1.05 or more, such as 1.1 or more, is desirable. Such an ODB value demonstrates good optical density, i.e., formation of a strong black color with good contrast to the background. It can be seen that the ODB value of Example 1 is greater than that of Comparative Example 1, and thus the composition of Example 1 demonstrates improved optical density and color / image formation. This is a result of increased heat transfer from the near infrared absorbing compound to the color forming compound via the heat transfer agent.

[0230] [Example 2] Compositions according to the present invention were prepared according to Table 3. All amounts are expressed as weight percentage (wt%).

[0231] [Table 3]

[0232] The composition was diluted with water to give a printing viscosity of 270 cP (0.27 Pascal seconds) and was gravure printed onto a paper substrate at 3 gsm.

[0233] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations, facilitating the formation of an image.

[0234] [Example 3] A composition according to the invention was prepared according to Table 3, but substituting aluminum zinc oxide for zirconium oxide. All amounts are expressed as weight percentages (wt%).

[0235] The composition was diluted with water to give a printing viscosity of 270 cP (0.27 Pascal seconds) and was gravure printed onto a paper substrate at 3 gsm.

[0236] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations, facilitating the formation of an image.

[0237] [Example 4] A composition according to the invention was prepared according to Table 3, but substituting titanium dioxide TR52 for zirconium oxide. All amounts are expressed as weight percentages (wt%).

[0238] The composition was diluted with water to give a printing viscosity of 270 cP (0.27 Pascal seconds) and was gravure printed onto a paper substrate at 3 gsm.

[0239] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations, facilitating the formation of an image.

[0240] [Comparative Example 2] Compositions without the heat transfer agent were prepared according to Table 4. All amounts are expressed as weight percentages (wt%).

[0241] [Table 4]

[0242] The composition was diluted with water to give a printing viscosity of 270 cP (0.27 Pascal seconds) and was gravure printed onto a paper substrate at 3 gsm.

[0243] A fiber diode laser with a wavelength of 1070 nm was then used to apply near infrared radiation to the composition at the localized locations, thus forming color at the localized locations. Black color was formed at these localized locations, facilitating the formation of an image.

[0244] Background Coloration Measurements for Examples 2, 3, and 4 and Comparative Example 2 This measurement demonstrates how the presence of the heat transfer agent in the composition according to the invention does not contribute to background coloration.

[0245] ΔE was calculated using an X-Rite SpectroEye spectrophotometer.

[0246] The L of the composition after application to the substrate but before exposure to near infrared radiation * a * b * Values ​​were measured for Examples 2, 3 and 4 and Comparative Example 2 (CIE L * a * b * Color system, L * indicates brightness, and a * indicates the red / green value, and b* (Indicates the yellow / blue value). These L values ​​of Examples 2, 3 and 4 and Comparative Example 2 were then * a * b * The measurements are compared with the L of a standard white tile. * a * b * Used in tandem with the measurements, the ΔE value of each of Examples 2, 3 and 4 and Comparative Example 2 was determined, i.e., the visually perceived difference between the color of the composition of Examples 2, 3, 4 or Comparative Example 2 and a white tile. ΔE is a standard mathematical calculation that allows for the visual quantification of the difference between two colors, i.e., the background color of the composition of Examples 2, 3, 4 or Comparative Example 2 and a white tile. The calculation is as follows:

[0247]

number

[0248] In Example 2, ΔE was calculated to be 3.05. In Example 3, ΔE was calculated to be 3.55. In Example 4, ΔE was calculated to be 3.2. In Comparative Example 2, ΔE was calculated to be 3.73. The difference between the ΔE values ​​of Example 2 and Comparative Example 2 is 0.68. The difference between the ΔE values ​​of Example 3 and Comparative Example 2 is 0.18. The difference between the ΔE values ​​of Example 4 and Comparative Example 2 is 0.53. ΔE values ​​less than 2 are indistinguishable by the human eye. Thus, the ΔE values ​​measured for Examples 2, 3 and 4 and Comparative Example 2 demonstrate that the heat transfer agent does not significantly affect the background coloring of the composition according to the present invention. In addition, the low ΔE values ​​of Examples 2, 3 and 4 demonstrate lower background coloring than Comparative Example 2 for improved laser imaging performance.

[0249] Optical Density Black (ODB) Measurements for Examples 2, 3 and 4 and Comparative Example 2 ODB was calculated using an X-Rite SpectroEye spectrophotometer.

[0250] In Example 2, the ODB was measured to be 1.25. In Example 3, the ODB was measured to be 1.16. In Example 4, the ODB was measured to be 1.2. In Comparative Example 2, the ODB was measured to be 0.85.

[0251] An ODB value of 1.05 or more, for example 1.1 or more, is desirable. Such an ODB value demonstrates good optical density, i.e., formation of a strong black color with good contrast to the background. It can be seen that the ODB value of Comparative Example 2 is less than 1.05, as well as the ODB values ​​of Examples 2, 3 and 4 are greater than Comparative Example 2, and thus the compositions of Examples 2, 3 and 4 demonstrate improved optical density and color / image formation. This is a result of increased heat transfer from the near infrared absorbing compound to the color-forming compound via the heat transfer agent. The present invention includes the following aspects. <1> 1. A composition comprising: a near infrared absorbing compound; a color forming compound; and a heat transfer agent that functions to facilitate heat transfer from the near infrared absorbing compound to the color forming compound, wherein the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the total composition, the heat transfer agent is present in an amount of 1 to 15 wt % of the total composition, and the heat transfer agent is present in the composition as solid particles. <2> 1. A composition comprising: a near infrared absorbing compound; a color forming compound; and a heat transfer agent that functions to facilitate heat transfer from said near infrared absorbing compound to said color forming compound, wherein a ratio of near infrared absorbing compound to heat transfer agent in a laser reactive composition is from 1:1 to 1:100, and said heat transfer agent is present in said composition as solid particles. <3> 1. A composition comprising: a near infrared absorbing compound; a color forming compound; and a heat transfer agent operable to facilitate transfer of heat from the near infrared absorbing compound to the color forming compound, wherein the heat transfer agent is selected from a metal oxide, a metal pyrophosphate, and a metal phosphate, and wherein the heat transfer agent is present in the composition as solid particles. <4> the heat transfer agent is selected from metal oxides, metal pyrophosphates, and metal phosphates; <1> or <2> The composition described in <5> The heat transfer agent is a metal oxide, metal pyrophosphate, and metal phosphate of the following metals: iron, aluminum, zinc, zirconium, and titanium, or combinations thereof; <3> or <4> The composition described in <6> The heat transfer agent is a metal oxide. <1> from <5> 2. The composition according to claim 1 . <7> The heat transfer agent has a D50 particle size distribution value of 5 μm or less, preferably 0.1 to 4 μm, for example 0.1 to 3 μm, most preferably 0.5 to 2 μm. <1> from <6> 2. The composition according to claim 1 . <8> The color-forming compound is selected from a leuco dye, an oxoanion of a polyvalent metal, a diacetylene compound, a keto acid compound, or a combination thereof; <1> from <7> 2. The composition according to claim 1 . <9> The ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1 to 1:50, preferably 1:1 to 1:20. <1> or <3> ,or <1> or <3> When subordinate to <4> from <8> 2. The composition according to claim 1 . <10> The ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1.5 to 1:18. <1> from <9> 2. The composition according to claim 1 . <11> The ratio of the near infrared absorbing compound to the heat transfer agent in the composition is 1:1.7 to 1:15, preferably 1:4 to 1:15, and more preferably 1:5 to 1:15. <10> The composition described in <12> the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the composition, and the heat transfer agent is present in an amount of 1 to 15 wt % of the composition. <2> or <3> ,or <2> or <3> When subordinate to <4> from <11> 2. The composition according to claim 1 . <13> the near infrared absorbing compound is present in an amount of 0.2 to 1.75 wt % of the composition, and the heat transfer agent is present in an amount of 2 to 12 wt % of the composition, preferably 2 to 10 wt % of the composition; <1> from <12> 2. The composition according to claim 1 . <14> the near infrared absorbing compound is present in an amount of 0.5 to 1.5 wt % of the composition, preferably 0.5 to 1 wt % of the composition, and the heat transfer agent is present in an amount of 2 to 10 wt %, preferably 2.5 to 10 wt %, more preferably 3 to 10 wt %, more preferably 5 to 10 wt % of the composition; <13> The composition described in <15> The near infrared absorbing compound is selected from inorganic copper salts, organic NIR dyes and pigments, non-stoichiometric inorganic compounds, and conductive polymers, preferably inorganic copper salts and non-stoichiometric inorganic compounds; <1> from <14> 2. The composition according to claim 1 . <16> further comprising one or more binder and carrier components; <1> from <15> 2. The composition according to claim 1 . <17> the one or more binder and carrier components are selected from polymeric binders such as acrylic polymers, styrene polymers, styrene-acrylic copolymers and hydrogenated products thereof; vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride and polyvinyl butyral; polyolefins and hydrogenated or epoxidized products thereof; aldehyde-containing polymers; epoxide-containing polymers; polyamides; polyesters; polyurethanes; sulfone-containing polymers; natural products and derivatives thereof; cellulosic polymers such as nitrocellulose; and combinations thereof, preferably the one or more binder and carrier components are selected from acrylic polymers, styrene polymers, styrene-acrylic copolymers, vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride and polyvinyl butyral, polyamides; polyurethanes; and cellulosic polymers such as nitrocellulose; and combinations thereof, more preferably the one or more binder and carrier components are styrene-acrylic copolymers, cellulosic polymers such as nitrocellulose, and polyurethanes; and combinations thereof, <16> The composition described in <18> the one or more binder and carrier components have a glass transition temperature of −60 to 120° C., for example −10 to 120° C., or 20 to 115° C., or even 40 to 110° C.; <16> or <17> The composition described in <19> The one or more binder and carrier components have a glass transition temperature of −60 to 40° C., preferably −55 to 30° C., more preferably −50 to 25° C.; <16> or <17> The composition described in <20> the one or more binder and carrier components have a minimum film-forming temperature of from −10 to 120° C., such as from −10 to 115° C., or even from 40 to 110° C.; <16> from <18> 2. The composition according to claim 1 . <21> the one or more binder and carrier components have a minimum film-forming temperature of −10 to 40° C., preferably −10 to 35° C., more preferably −5 to 30° C., more preferably −5 to 25° C.; <16> , <17> or <19> 2. The composition according to claim 1 . <22> Applied onto a substrate <1> from <21> A substrate comprising the composition according to any one of claims 1 to 5. <23> The composition exhibits a color. <22> The substrate according to claim 1. <24> The composition exhibits an image. <22> or <23> The substrate according to claim 1. <25> The substrate is a heat-sensitive substrate; <22> from <24> 2. The substrate according to claim 1 . <26> further comprising one or more additional layers applied onto the substrate to form a multi-layer structure; <22> from <25> 2. The substrate according to claim 1 . <27> A multi-layer substrate structure. <22> from <26> 2. The substrate according to claim 1 . <28> 28. A method for forming a substrate according to any one of claims 22 to 27, comprising the steps of: <1> from <21> A method comprising applying the composition according to any one of claims 1 to 5 to a substrate. <29> further comprising applying one or more additional layers to the substrate to form a multi-layer structure. <28> The method according to <30> The substrate is a multi-layer substrate structure; <28> or <29> The method according to <31> Applied onto a substrate <1> from <21> 2. A method for forming a color on a substrate comprising the composition of claim 1, comprising exposing the composition to near infrared or mid infrared radiation to form a color on the substrate. <32> Applied onto a substrate <1> from <21> 2. A method for forming an image on a substrate comprising the composition of claim 1, comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate. <33> the near infrared or mid-infrared radiation is applied at a localized location to selectively develop the color of the color forming compound; <31> or <32> The method according to <34> In the formation of color on a substrate by application of near or mid-infrared radiation, <1> from <21> 2. Use of the composition according to any one of claims 1 to 11. <35> In forming an image on a substrate by application of near infrared or mid infrared radiation, <1> from <21> 2. Use of the composition according to any one of claims 1 to 11.

Claims

1. a composition comprising: a near infrared absorbing compound; a color forming compound; and a heat transfer agent operable to facilitate heat transfer from said near infrared absorbing compound to said color forming compound, wherein a ratio of near infrared absorbing compound to heat transfer agent in the composition is from 1:1 to 1:100, and said heat transfer agent is present in said composition as solid particles; the heat transfer agent is selected from metal oxides, metal pyrophosphates, and metal phosphates; The color-forming compound is selected from a leuco dye, an oxoanion of a polyvalent metal, a diacetylene compound, a keto acid compound, or a combination thereof; composition.

2. 10. The composition of claim 1, wherein the heat transfer agent is a metal oxide, metal pyrophosphate, or metal phosphate of the following metals: iron, aluminum, zinc, zirconium, and titanium, or combinations thereof.

3. The composition of claim 1 or 2, wherein the heat transfer agent is a metal oxide.

4. 4. The composition of claim 1, wherein the heat transfer agent has a D50 particle size distribution value of 5 μm or less.

5. 5. The composition according to claim 1, wherein a ratio of the near infrared absorbing compound to the heat transfer agent in the composition is from 1:1 to 1:

50.

6. 6. The composition according to any one of claims 1 to 5, wherein a ratio of the near infrared absorbing compound to the heat transfer agent in the composition is from 1:1.5 to 1:

18.

7. 7. The composition of claim 6, wherein a ratio of the near infrared absorbing compound to the heat transfer agent in the composition is from 1:1.7 to 1:

15.

8. 8. The composition of any of the preceding claims, wherein the near infrared absorbing compound is present in an amount of 0.1 to 3.5 wt % of the composition, and the heat transfer agent is present in an amount of 1 to 15 wt % of the composition.

9. 9. The composition of any of the preceding claims, wherein the near infrared absorbing compound is present in an amount of 0.2 to 1.75 wt % of the composition and the heat transfer agent is present in an amount of 2 to 12 wt % of the composition.

10. 10. The composition of claim 9, wherein the near infrared absorbing compound is present in an amount of 0.5 to 1.5 wt % of the composition and the heat transfer agent is present in an amount of 2 to 10 wt % of the composition.

11. 11. The composition of claim 1, wherein the near infrared absorbing compound is selected from inorganic copper salts, organic NIR dyes and pigments, non-stoichiometric inorganic compounds, and conductive polymers.

12. 12. The composition of any of claims 1 to 11, further comprising one or more binder and carrier components.

13. 13. The composition of claim 12, wherein the one or more binder and carrier components are selected from polymeric binders; vinyl polymers; polyolefins and their hydrogenated or epoxidized products; aldehyde-containing polymers; epoxide-containing polymers; polyamides; polyesters; polyurethanes; sulfone-containing polymers; natural products and their derivatives; cellulosic polymers; and combinations thereof.

14. The composition of claim 12 or 13, wherein the one or more binder and carrier components have a glass transition temperature of from -60 to 120°C.

15. The composition of claim 12 or 13, wherein the one or more binder and carrier components have a glass transition temperature of from -60 to 40°C.

16. The composition of any of claims 12 to 14, wherein the one or more binder and carrier components have a minimum film-forming temperature of from -10 to 120°C.

17. 16. The composition of any of claims 12, 13 or 15, wherein the one or more binder and carrier components have a minimum film forming temperature of from -10 to 40°C.

18. A substrate comprising the composition of any of claims 1 to 17 applied thereon.

19. The substrate of claim 18 , wherein the composition exhibits a color.

20. 20. The substrate of claim 18 or 19, wherein the composition displays an image.

21. The substrate of any of claims 18 to 20, wherein the substrate is a heat-sensitive substrate.

22. 22. The substrate of any of claims 18 to 21, further comprising one or more additional layers applied over the substrate to form a multi-layer structure.

23. 23. The substrate of any of claims 18 to 22 which is a multi-layer substrate structure.

24. 24. A method of forming a substrate according to any one of claims 18 to 23, comprising applying a composition according to any one of claims 1 to 17 to a substrate.

25. 25. The method of claim 24, further comprising applying one or more additional layers to the substrate to form a multi-layer structure.

26. 26. The method of claim 24 or 25, wherein the substrate is a multi-layer substrate structure.

27. 18. A method of forming a color on a substrate comprising the composition of any of claims 1 to 17 applied thereon, the method comprising exposing the composition to near infrared or mid infrared radiation to form a color on the substrate.

28. 20. A method of forming an image on a substrate comprising the composition of claim 1 applied onto a substrate, the method comprising exposing the composition to near infrared or mid infrared radiation to form an image on the substrate.

29. 29. The method of claim 27 or 28, wherein the near infrared or mid infrared radiation is applied at a localized location to selectively cause the color forming compound to develop color.

30. 18. Use of a composition according to any one of claims 1 to 17 in the formation of colour on a substrate by application of near or mid infrared radiation.

31. 18. Use of a composition according to any one of claims 1 to 17 in the formation of an image on a substrate by application of near or mid infrared radiation.

32. The composition of claim 4, wherein the heat transfer agent has a D50 particle size distribution value of 0.1 to 4 μm.

33. The composition of claim 4 or 32, wherein the heat transfer agent has a D50 particle size distribution value of 0.1 to 3 μm.

34. The composition of claim 4, 32, or 33, wherein the heat transfer agent has a D50 particle size distribution value of 0.5 to 2 μm.

35. The composition of claim 5, wherein the ratio of near infrared absorbing compound to heat transfer agent in the composition is 1:1 to 1:

20.

36. The composition of claim 7, wherein the ratio of near infrared absorbing compound to heat transfer agent in the composition is 1:4 to 1:

15.

37. The composition described in claim 7 or 36, wherein the ratio of near infrared absorbing compound to heat transfer agent in the composition is 1:5 to 1:

15.

38. The composition of claim 9, wherein the heat transfer agent is present in an amount of 2 to 10 wt % of the composition.

39. The composition of claim 10, wherein the near infrared absorbing compound is present in an amount of 0.5 to 1 wt % of the composition.

40. The composition described in claim 10 or 39, wherein the heat transfer agent is present in an amount of 2.5 to 10 wt % of the composition.

41. The composition of claim 40, wherein the heat transfer agent is present in an amount of 3 to 10 wt % of the composition.

42. The composition of claim 40 or 41, wherein the heat transfer agent is present in an amount of 5 to 10 wt % of the composition.

43. The composition of claim 11, wherein the near infrared absorbing compound is selected from inorganic copper salts and non-stoichiometric inorganic compounds.

44. The composition of claim 13, wherein the one or more binder and carrier components are selected from acrylic polymers, styrene polymers, styrene-acrylic copolymers, vinyl polymers, polyamides, polyurethanes, and cellulosic polymers, and combinations thereof.

45. The composition of claim 14, wherein the one or more binder and carrier components have a glass transition temperature of -10 to 120°C.

46. ​​The composition of claim 15, wherein the one or more binder and carrier components have a glass transition temperature of -55 to 30°C.

47. The composition of claim 16, wherein the one or more binder and carrier components have a minimum film forming temperature of from -10 to 115°C.

48. The composition of claim 17, wherein the one or more binder and carrier components have a minimum film forming temperature of -10 to 35°C.

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