Coated printing substrate and method for its production

Abstract

A method for preparing a coated printing substrate is provided, the method comprising (a) providing a printing substrate, wherein the substrate comprises a surface having one or more regions on which an ink layer is present; (b) combining Component A and Component B to form a urethane coating composition, wherein Component A comprises a polyisocyanate prepolymer A1, wherein the polyisocyanate prepolymer A1 is the reaction product of a polyisocyanate monomer A1a and an isocyanate polyreactive compound A1b, wherein Component B comprises one or more polyols B1, wherein the urethane coating composition has an isocyanate index greater than 0.9; (c) applying a layer of the urethane coating composition to the surface. A coated printing substrate made by this method is also provided.

Description

[0001] It is often desirable to use printing inks to create images on plastic surfaces. Then, it is usually desirable to protect the printed surface. Without protection, the image is easily damaged, for example by scratches that may occur during transport or handling, and / or by deformation when the printed surface is heated, for example, during a sealing operation. In the past, it was common to protect the printed image by attaching a clear plastic cover film to the printed surface through lamination. Such laminations often have one or more of the following undesirable characteristics: increased complexity of the manufacturing process or increased cost.

[0002] WO2016 / 196168 describes a coated membrane in which the membrane comprises polyethylene and the coating comprises polyurethane.

[0003] It is desirable to provide a method for manufacturing a coated printing substrate having one or more of the following advantages: good appearance, good abrasion resistance, good high-temperature resistance, and / or good chemical resistance. Preferably, the coated printing substrate has one or more of these advantages to a degree sufficient to eliminate the need for an overlay plastic layer to be attached to the coated surface.

[0004] The following is the invention summary.

[0005] A first aspect of the present invention is a method for preparing a coated printing substrate, the method comprising:

[0006] (a) Providing a printing substrate, wherein the substrate includes a surface of one or more regions on which an ink layer is present, wherein the ink comprises:

[0007] (i) one or more olefin copolymers, and

[0008] (ii) one or more appearance additives, wherein the one or more appearance additives are selected from one or more pigments, one or more dyes, and mixtures thereof, and

[0009] (iii) One or more conductive additives.

[0010] (b) Combining component A and component B to form a urethane coating composition.

[0011] Component A includes polyisocyanate prepolymer A1, which is the reaction product of polyisocyanate monomer A1a and polyisocyanate multireactive compound A1b.

[0012] Component B includes one or more polyols B1.

[0013] The urethane coating composition has an isocyanate index greater than 0.9, and

[0014] (c) Apply a layer of the urethane coating composition to the surface.

[0015] A second aspect of the present invention is a coated printing substrate manufactured by the method of the first aspect of the present invention.

[0016] This is a detailed description of the present invention.

[0017] As used herein, the following terms have specified definitions unless the context clearly indicates otherwise.

[0018] As used herein, “polymer” and “plastic” are synonymous. A polymer is a molecule made up of many repeating units. There may be more than one type of repeating unit; that is, a polymer can be a homopolymer (with only one type of repeating unit) or a copolymer (with more than one type of repeating unit). Polymers have a molecular weight of 5,000 or greater. Polymers can be linear, branched, cross-linked, or any combination thereof.

[0019] Polyolefins are polymers in which 75% by weight or more of the repeating units have structure I:

[0020]

[0021] Where R 1 R 2 R 3 and R 4 Each of these is independently a hydrogen or olefin group. R 1 R 2 R 3 and R 4 Either of them can be used with R 1 R 2 R 3 and R 4 The other one in R is the same as or different from R. 1 R 2 R 3 and R 4 Any two or more of them can be joined together to form a ring structure.

[0022] Polyethylene is a polymer in which 75% by weight or more of the repeating units have structure II (“ethylene units”):

[0023]

[0024] As used herein, an olefin copolymer is a polymer having repeating units of structure I and also having repeating units containing one or more oxygen atoms. Suitable oxygen-containing repeating units include, for example, acrylic units (structure III), ester units (structure IV), and carbonyl units (structure V):

[0025]

[0026] R 5 It is either methyl or hydrogen, and R 6 It is hydrogen or a substituted or unsubstituted alkyl group. R 8 and R 9 Each is an alkyl group, either substituted or unsubstituted, independently of the others. Suitable substituents include hydroxyl groups, carboxyl groups, nitrogen-containing groups, groups containing carbon-carbon double bonds, other substituents, and combinations thereof. In olefin copolymers, the repeating units of structure I and the one or more oxygen-containing repeating units can be arranged in the copolymer in any order, including, for example, random, alternating, block, branched, or any combination thereof. In olefin copolymers, 75% or more of the repeating units by weight of the polymer are structure I or oxygen-containing repeating units.

[0027] As used herein, an isocyanate reactive group is a chemical group capable of reacting with an isocyanate group to form a covalent bond between the isocyanate group and the isocyanate reactive group. A complete isocyanate group is an isocyanate group that has not yet reacted with an isocyanate reactive group.

[0028] Compounds having one or more isocyanate reactive groups can be characterized by functionality, i.e., the number of isocyanate reactive groups per molecule. In a mixture of compounds where each molecule has one or more isocyanate reactive groups, the functionality of the mixture is the number-average functionality. Similarly, compounds having one or more isocyanate groups can be characterized by functionality, i.e., the number of isocyanate groups per molecule. In a mixture of compounds where each molecule has one or more isocyanate groups, the functionality of the mixture is the number-average functionality.

[0029] Compounds having isocyanate reactive groups and a functionality of 2 or higher are referred to herein as “isocyanate multireactive” compounds.

[0030] Polyols are compounds having two or more hydroxyl groups. Polyols with two or more ether bonds are polyether polyols. Polyols with two or more ester bonds are polyester polyols. Polyols with two or more urethane bonds are polyurethane polyols. Polyols with two or more carbonate bonds are polycarbonate polyols. Polyols with two or more residues from the ring-opening polymerization of ε-caprolactone are polycaprolactone polyols. Polyols can be characterized by the number of OH groups, as determined by testing ASTM D4274-16 (American Society of Testing and Materials, Conshohocken, PA, USA). Low molecular weight polyols have a molecular weight of 300 or less.

[0031] Compositions containing complete isocyanate groups can be characterized by an "isocyanate index," which is the ratio of the number of all complete isocyanate groups in the composition to the number of all complete isocyanate reactive groups in the composition. Compositions containing complete isocyanate groups can also be characterized by "NCO content," which is the weight percentage of isocyanate groups on the weight of the composition as determined by testing ASTM D2572-19 (American Society of Testing and Materials, Conshohocken, PA, USA). If the composition contains a solvent, the NCO content can be reported as "solvent-containing," meaning the percentage of NCO content is based on the weight of the entire composition, or it can be reported as "solvent-free," meaning the percentage of NCO content is based on the weight of the non-solvent portion of the composition.

[0032] Compounds containing one or more isocyanate groups per molecule are isocyanates. Compounds containing two or more isocyanate groups per molecule are polyisocyanates. Isocyanates with one or more aromatic rings in their molecules are aromatic isocyanates. Isocyanates without aromatic rings in their molecules are aliphatic isocyanates. Polyisocyanate monomers are polyisocyanates with a molecular weight of 700 or lower.

[0033] As used herein, the solvent is a compound that is liquid in a temperature range of 10°C to 30°C and does not participate in the chemical reaction between the isocyanate groups and the isocyanate reactive groups. The solvent has a boiling point of 200°C or lower.

[0034] As used herein, aliphatic compounds are compounds containing a straight-chain hydrocarbon group having eight or more carbon atoms bonded to each other in a straight line. Aliphatic compounds containing a carboxyl group or a carboxylate anion are fatty acids. Aliphatic compounds containing a hydroxyl group are fatty alcohols.

[0035] As used herein, fatty triglycerides are compounds having a triester structure consisting of glycerol and three fatty acids. The portion of a fatty triglyceride derived from one of the fatty acids (if the fatty triglyceride has been formed through an esterification reaction between the fatty acid and glycerol) is referred to as a fatty acid residue. As used herein, natural oil polyols are fatty triglycerides having two or more hydroxyl groups.

[0036] As used herein, wax esters are compounds having an ester structure of fatty acids and fatty alcohols and being solid in a temperature range including 10°C to 40°C. Mixtures of wax esters are also referred to herein as wax esters. The term "wax ester" also includes mixtures in which 80% by weight or more of the components consist of one or more wax esters, while the remaining 20% ​​by weight or less of the components consist of substances that are not wax esters.

[0037] As used herein, a printing surface is a surface on which one or more areas of printing ink are present. On the printing surface, the printing ink is dry, meaning that the printing ink contains 10% or less by weight of all compounds with a boiling point of 120°C or lower. The printing ink contains 15% by weight or more by weight of one or more olefin copolymers. The printing ink also contains one or more pigments, one or more dyes, or mixtures thereof. Digital printing inks also contain one or more conductive additives. Conductive additives are also known as charge-directing agents or imaging agents. Conductive additives increase the electrical conductivity of the ink.

[0038] As used herein, surface wettability refers to the tendency of a liquid placed on a surface to form a thin, extended layer rather than a rounded, localized bead. The greater the tendency of such a liquid to form a thin, extended layer rather than a rounded, localized bead, the better the wettability is considered in this context. Specifically, in this context, the category of liquids used to evaluate wettability is a category of liquids containing 50% by weight or more of one or more hydrocarbon compounds and further containing (i) one or more ethylene copolymers, (ii) one or more appearance additives selected from one or more pigments, one or more dyes, and mixtures thereof, and (iii) one or more imaging agents.

[0039] As used herein, TDI is toluene diisocyanate and MDI is diphenylmethane diisocyanate.

[0040] This invention relates to a coating composition formed by combining component A and component B.

[0041] Component A contains one or more polyisocyanates. Component A preferably contains one or more prepolymers A1, which are reaction products of one or more polyisocyanate monomers A1a and one or more polyisocyanate multireactive compounds A1b. Prepolymer A1 is a polyisocyanate. Polyisocyanate monomer A1a preferably contains one or more aromatic polyisocyanate monomers, or one or more aliphatic polyisocyanate monomers, or blends thereof. More preferably, polyisocyanate monomer A1a contains one or more aromatic polyisocyanate monomers. More preferably, polyisocyanate monomer A1a contains one or more monomers selected from: 2,6-TDI, 2,4-TDI, 2,4′-MDI, 4,4′-MDI, and mixtures thereof.

[0042] The isocyanate multireactive compound A1b preferably contains one or more polyols. Suitable polyols for isocyanate multireactive compound A1b include, for example, polyether polyols, polyester polyols, polyether-polyester polyols, polyurethane polyols, polycarbonate polyols, polycaprolactone polyols, natural oil polyols, and blends thereof. Preferred polyols for isocyanate multireactive compound A1b are polyether polyols, polyester polyols, and blends thereof. More preferred are polyether polyols, low molecular weight polyols, and blends thereof. Suitable low molecular weight polyols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, triisopropanolamine, and blends thereof.

[0043] Preferably, the isocyanate multireactive compound A1b contains one or more isocyanate multireactive compounds with a functionality of 2 or greater. Preferably, the isocyanate multireactive compound A1b contains one or more isocyanate multireactive compounds with a functionality of 6 or less, more preferably 5 or less, more preferably 4 or less.

[0044] When the isocyanate multireactive compound A1b contains one or more polyols, the polyols preferably have a molecular weight of 50 or greater, more preferably 100 or greater. When the isocyanate multireactive compound A1b contains one or more polyols, the polyols preferably have a molecular weight of 4000 or less, more preferably 2000 or less.

[0045] Component A may or may not contain a solvent. Examples of suitable solvents are ethyl acetate, propyl acetate, cyclohexane, methyl acetate, methyl ether ketone, toluene, and mixtures thereof. Preferred solvents are ethyl acetate, propyl acetate, cyclohexane, methyl ether ketone, and mixtures thereof; more preferred solvents are ethyl acetate, propyl acetate, cyclohexane, and mixtures thereof.

[0046] If a solvent is present in component A, then preferably all components of component A are dissolved in the solvent. Preferably, the amount of solvent in component A is 20% by weight or more, more preferably 30% by weight or more, based on the weight of component A. Preferably, the amount of solvent in component A is 70% by weight or less, more preferably 50% by weight or less, based on the weight of component A.

[0047] Preferably, the NCO content of component A containing solvent is 5% or more, more preferably 7% or more. Preferably, the NCO content of component A containing solvent is 15% or less, more preferably 13% or less. Preferably, the NCO content of component A without solvent is 8% or more, more preferably 12% or more. Preferably, the NCO content of component A without solvent is 25% or less, more preferably 22% or less.

[0048] Preferably, component A contains one or more fatty triglycerides. More preferably, it is a fatty triglyceride, wherein one or more fatty acid residues have 12 or more carbon atoms, more preferably 16 or more carbon atoms. More preferably, it is a fatty triglyceride, wherein one or more fatty acid residues have one or more carbon-carbon double bonds.

[0049] Preferably, the amount of fatty triglycerides in component A is 0.1% by weight or more, more preferably 0.2% by weight or more, and even more preferably 0.3% by weight or more, based on the weight of component A. Preferably, component A contains one or more fatty triglycerides. Preferably, the amount of fatty triglycerides in component A is 10% by weight or less, more preferably 5% by weight or less, and even more preferably 3% by weight or less, based on the weight of component A.

[0050] Preferably, component A contains one or more wax esters. Examples of suitable wax esters include, but are not limited to, cetyl palmitate, palmitate stearate, octadecyl stearate, hydrogenated tallow, carnauba wax, beeswax, and mixtures thereof. Preferred are cetyl palmitate, palmitate stearate, octadecyl stearate, hydrogenated tallow, and mixtures thereof. More preferred are mixtures of cetyl palmitate, palmitate stearate, octadecyl stearate, and hydrogenated tallow.

[0051] Preferably, the amount of wax ester in component A is 0.1% by weight or more, more preferably 0.2% by weight or more, and even more preferably 0.3% by weight or more, based on the weight of component A. Preferably, the amount of wax ester in component A is 10% by weight or less, more preferably 5% by weight or less, and even more preferably 3% by weight or less, based on the weight of component A.

[0052] Component B contains one or more isocyanate multireactive compounds B1. Preferably, the isocyanate multireactive compound B1 contains one or more polyols. Suitable polyols included in the isocyanate multireactive compound B1 include, for example, polyether polyols, polyester polyols, polyether polyester polyols, polyurethane polyols, polycarbonate polyols, polycaprolactone polyols, natural oil polyols, and blends thereof.

[0053] Preferably, the isocyanate multireactive compound B1 contains one or more polyurethane polyols. The polyurethane polyol suitable for the isocyanate multireactive compound B1 is preferably the reaction product of one or more polyisocyanate monomers B1a and one or more polyols B1b. The polyisocyanate monomer B1a can be an aromatic polyisocyanate, an aliphatic polyisocyanate, or a blend thereof. Preferably, the polyisocyanate monomer B1a contains one or more... Fangzu Polyisocyanate monomers. Preferred polyisocyanate monomers in B1a are 2,6-TDI, 2,4-TDI, 2,2′-MDI, 2,4′-MDI, 4,4′-MDI, and mixtures thereof. Preferably, polyisocyanate monomer B1a contains one or more polyisocyanate monomers with a functionality of 2 or higher.

[0054] Suitable polyols for inclusion in polyol B1b include, for example, polyether polyols, polyester polyols, polyether polyester polyols, polyurethane polyols, polycarbonate polyols, polycaprolactone polyols, natural oil polyols, and blends thereof. Preferred polyols for polyol B1b are polyether polyols, low molecular weight polyols, and blends thereof. Suitable low molecular weight polyols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, triisopropanolamine, and blends thereof.

[0055] Preferably, the amount of polyurethane polyol B1PU in component B is 20% by weight or more, more preferably 30% by weight or more, and even more preferably 49% by weight or more, based on the weight of component B. Preferably, the amount of polyurethane polymer B1PU in component B is 95% by weight or less, more preferably 85% by weight or less, and even more preferably 75% by weight or less, based on the weight of component B. Preferably, one or more of the polyols included in polyol B1b do not react with the isocyanate compound and are present in component B.

[0056] Preferably, component B comprises one or more anti-caking agents. Anti-caking agents reduce caking on the surface of polymer films and other plastic articles to facilitate film processing and handling. Anti-caking agents can be inorganic or organic. Examples of inorganic anti-caking agents include, but are not limited to, talc and silica. Examples of organic anti-caking agents include, but are not limited to, cellulose acetate butyrate. Mixtures of anti-caking agents are also suitable.

[0057] Preferably, the amount of anti-caking agent in component B is 0.05% by weight or more, more preferably 0.1% by weight or more, and even more preferably 0.2% by weight or more, based on the weight of component B. Preferably, the amount of anti-caking agent in component B is 10% by weight or less, more preferably 5% by weight or less, and even more preferably 3% by weight or less, based on the weight of component B.

[0058] Preferably, component B comprises one or more wetting agents. When a liquid is applied to a surface in the form of a layer, the wetting agent improves the flow and leveling properties of the liquid and reduces any tendency for the liquid to form pinholes, fisheyes, pits, speckled surfaces (also known as "orange peel"), or any combination thereof. Examples of suitable wetting agents include, but are not limited to, acrylic polymers, siloxanes, and mixtures thereof.

[0059] Preferably, the amount of wetting agent in component B is 0.05% by weight or more, more preferably 0.1% by weight or more, more preferably 0.2% by weight or more, based on the weight of component B. Preferably, the amount of wetting agent in component B is 10% by weight or less, more preferably 5% by weight or less, more preferably 3% by weight or less, based on the weight of component B.

[0060] Component B may or may not contain a solvent. Examples of suitable solvents are ethyl acetate, propyl acetate, cyclohexane, methyl acetate, methyl ether ketone, toluene, and mixtures thereof. Preferred solvents are ethyl acetate, propyl acetate, cyclohexane, methyl ether ketone, and mixtures thereof; more preferred solvents are ethyl acetate, propyl acetate, cyclohexane, and mixtures thereof.

[0061] If a solvent is present in component B, then preferably all components of component B are dissolved in the solvent. Preferably, the amount of solvent in component B is 5% by weight or more, more preferably 10% by weight or more, based on the weight of component B. Preferably, the amount of solvent in component B is 80% by weight or less, more preferably 70% by weight or less, based on the weight of component B.

[0062] In practice, components A and B are combined, and the resulting mixture is a urethane coating composition. Preferably, components A and B are then thoroughly mixed. A layer of the coating composition is applied to a substrate. It is anticipated that the isocyanate groups in component A will react with the isocyanate reactive groups in component B. Preferably, the layer of the coating composition is applied to the substrate when 50 mol% or less of the isocyanate groups in component A has already reacted with the isocyanate reactive groups in component B.

[0063] It is useful to consider a mixture of components A and B before any chemical reaction occurs between them. The isocyanate index of the mixture is 0.9 or greater, preferably 1.0 or greater, more preferably 1.1 or greater, and even more preferably 1.2 or greater. The isocyanate index of the mixture is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.6 or less.

[0064] In practice, a layer of the urethane coating composition is applied to the surface of a printing substrate. Preferably, the surface of the substrate is subjected to a surface treatment at a certain time, after the ink has been applied to the substrate but before the layer of the urethane coating composition has been applied. Suitable surface treatments alter the surface energy of the substrate in a manner that improves the wettability of the substrate surface. Examples of suitable surface treatments include, for example, corona treatment and plasma treatment.

[0065] Preferably, the urethane coating composition is liquid at the temperature at which it is applied to the substrate prior to the curing process. Preferably, when the liquid urethane coating composition is applied to the printed surface of the substrate, it exhibits good wetting properties in both the areas of the substrate covered by the printed ink and the areas of the substrate in direct contact with the liquid urethane coating composition (if any). That is, the liquid urethane coating composition preferably forms a smooth, undamaged layer over the entire covered portion of the substrate, without gaps. Such gaps are sometimes observed, typically due to surface tension, when the liquid coating composition partially retracts from the substrate surface, forming structures such as "beads" or "fisheyes."

[0066] It is anticipated that after a layer of the urethane coating composition has been applied to a substrate, some or all of the isocyanate groups will react with some or all of the isocyanate reactive groups to form a cured polyurethane layer. To promote this reaction, the urethane coating composition layer can be heated. When 80 mol% or more of the isocyanate groups have reacted, the urethane coating composition layer is said herein to have become a cured polyurethane layer. If the urethane coating composition contains one or more solvents, preferably, the solvent is forced or allowed to evaporate from the coating composition after the layer of the urethane coating composition has been applied to the substrate. When the urethane coating composition layer is heated, it is anticipated that the behavior of the heated urethane coating composition layer on the substrate will promote solvent evaporation and accelerate the curing reaction.

[0067] Preferably, the average thickness of the cured polyurethane layer is 0.5 micrometers or more, more preferably 1 micrometer or more. Preferably, the average thickness of the cured polyurethane layer is 10 micrometers or less, more preferably 7.5 micrometers or less, more preferably 5 micrometers or less.

[0068] The substrate is a printing surface. Preferably, in the area of ​​the substrate covered by the urethane coating composition layer, the portion of the substrate covered by ink is 10% or more, more preferably 20% or more, more preferably 50% or more. Preferably, in the area of ​​the substrate covered by the urethane coating composition layer, the portion of the substrate covered by ink is 100% or less.

[0069] The ink is dry on the printing surface. The amount of olefin copolymer in the ink is 1% or more by weight, more preferably 5% or more by weight, more preferably 10% or more by weight, based on the weight of the ink. The amount of ethylene-acrylic copolymer in the ink is 99% or less by weight, more preferably 95% or less by weight, more preferably 90% or less by weight, based on the weight of the ink.

[0070] The ink contains one or more conductive additives. The amount of conductive additive in the ink, based on the weight of the dried ink, is preferably 0.5% by weight or more, more preferably 1% by weight or more, and even more preferably 1.5% by weight or more. The amount of conductive additive in the ink, based on the weight of the dried ink, is preferably 15% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less.

[0071] The thickness of the substrate is preferably from 20 micrometers to 200 micrometers. The substrate preferably comprises one or more polymers; preferably, the amount of polymer in the substrate is 50% or more, more preferably 75% or more, more preferably 90% or more. The substrate can be a single-layer polymer, or the substrate can be made of multiple layers of polymers. When the substrate has multiple layers, any layer may have the same composition as one or more of the other layers, or a layer may have a different composition from all the other layers. Any layer may optionally contain one or more impact modifiers or other additives. Compounds may optionally be present between layers, for example, to act as bonding layers and / or barrier layers.

[0072] The substrate layer in contact with the printing ink and the urethane coating composition of the present invention is referred to herein as the “top” layer of the substrate. Preferably, the top layer of the substrate contains one or more polyolefins or one or more polyesters or combinations thereof. Preferably, the amount of polyolefin in the top layer of the substrate is 50% or more by weight, more preferably 75% or more, more preferably 90% or more. Suitable polyolefins include, for example, polypropylene, polyethylene, and mixtures thereof. Suitable forms of polyethylene are, for example, linear polyethylene homopolymer (HDPE), linear low-density polyethylene, homopolymer, medium-density linear polyethylene homopolymer, low-density polyethylene homopolymer, and blends of two or more thereof. Suitable polyesters include, for example, polyethylene terephthalate.

[0073] The cured polyurethane layer is expected to be durable. That is, the cured polyurethane layer will resist degradation due to one or more of the following stress factors: scratching, exposure to corrosive chemicals, twisting, and heating.

[0074] The printed substrate is highly susceptible to any of the stress factors mentioned above if it is not protected to some extent (e.g., by a durable coating or by an additional lamination). Specifically, exposure to any of these stress factors will cause degradation in the appearance and / or adhesion of the printing ink to the substrate. Historically, to protect the printed surface, it was common practice to attach an additional polymer layer on top of the printed surface (i.e., to laminate an additional polymer layer onto the printed surface). Common additional polymers are polyethylene terephthalate and biaxially oriented polypropylene. Typically, the thickness of the additional polymer layer ranges from 8 to 25 micrometers.

[0075] Compared to previous practices involving the lamination of additional polymer layers, in the practice of this invention, the cured polyurethane layer provides a durable surface and eliminates the need for laminating additional polymer layers. Preferably, after the printed surface has been coated using the practice of this invention, it is not necessary to laminate additional polymer layers onto the coated printed surface.

[0076] Objects having the coated printed surface of the present invention can be used for any purpose. Suitable purposes include, for example, using objects having the coated printed surface of the present invention as part of pouches or other packaging, such as for containing food. Other purposes include, for example, packaging for household and personal care products, protective films, printed pads, and labels. Preferably, when objects having the coated printed surface of the present invention are used for any purpose, no additional polymer layer is laminated to the coated printed surface.

[0077] The following are embodiments of the present invention. Unless otherwise stated, the operation is carried out at room temperature (approximately 23°C).

[0078] Use the following test methods. (ASTM refers to the American Society of Testing and Materials, Conshohocken, PA, USA).

[0079] The wetting of the liquid coating composition on the printed substrate was visually evaluated. A smoother and more uniform liquid coating composition layer was rated as better wettability. Ridges and valleys were considered evidence of a lack of uniformity in the liquid coating composition layer.

[0080] Scratch resistance was assessed using ASTM D7027-05. Temperature resistance was tested using ASTM 1921. Gloss was assessed using ASTM D2457.

[0081] Chemical resistance was evaluated using the following test. 1 mL of a simulated solution was placed directly onto the coated ink on the printed film. The printed film was subjected to five cycles of manual twisting and flattening at 0.5 hours, 4 hours, and 24 hours. The film was then evaluated as follows:

[0082] Good: The ink and coating remain on the surface without changing.

[0083] Medium: Some ink and varnish are randomly removed from the film surface.

[0084] Poor: Ink and coating discoloration and complete removal from the film surface.

[0085] Temperature resistance was assessed using methods based on ASTM 1921 and ASTM D2457. Test results are the lowest temperatures at which samples begin to show significant damage, such as rapid shrinkage or film burning.

[0086] Various printing inks are used to create multicolor printed images. Before drying, the inks are believed to have an approximate composition as follows (by weight percentage of the printing ink):

[0087] Less than 80% petroleum hydrocarbons;

[0088] Less than 15% olefin copolymer;

[0089] Approximately 2.5% conductive additives;

[0090] Approximately 3.5% dyes and pigments.

[0091] The substrates used in the tests are as follows. The symbol "μm" refers to micrometers. Percentages are weight percentages based on the weight of the layer. "PA" is polyamide. Polyamide can be co-extruded with polyethylene and / or maleic anhydride modified polyethylene. I2 is the melt index measured at 90°C using 2.16 kg and reported in grams per 10 minutes. D is the density, in grams per cubic centimeter.

[0092]

[0093] Examples of using the coating compositions of the present invention.

[0094] Component A of Example 1

[0095]

[0096] To prepare composition A of Example 1, wax esters and trimethylolpropane were loaded into a reactor, followed by ethyl acetate. TDI was vacuum-loaded into the reactor and then rinsed with the remaining ethyl acetate. The batch was maintained at 70°C for 3 hours. The batch was then cooled to 55°C. The viscosity of the batch was measured. If the viscosity was less than 380 mPa*s (380 cP), the viscosity was adjusted to 380 mPa*s (380 cP) by adding trimethylolpropane. If the viscosity was greater than 380 mPa*s (380 cP), or after adding additional trimethylolpropane, the reactor was then cooled to 55°C. Corn oil was vacuum-loaded into the reactor. Cyclohexane was then added to the reactor, and the contents were maintained at 45°C and stirred for 45 minutes until the contents were clear. Benzoyl chloride was then vacuum-loaded into the reactor, and the contents were stirred for 15 minutes. The reactant composition A was then packaged for use.

[0097] Component A of Example 2

[0098]

[0099] To prepare composition A of Example 2, wax esters and trimethylolpropane were loaded into a reactor, followed by ethyl acetate. MDI was vacuum-loaded into the reactor and then washed with the remaining ethyl acetate. The batch was maintained at 70°C for 3 hours. The batch was then cooled to 55°C. Corn oil was vacuum-loaded into the reactor. Cyclohexane was then added to the reactor, and the contents were maintained at 45°C and stirred for 45 minutes until the contents became clear. Benzoyl chloride was then vacuum-loaded into the reactor, and the contents were stirred for 15 minutes. Reactant composition A was then packaged for use.

[0100] Component B of Example 1

[0101]

[0102] To prepare reactant composition B of Example 1, TIPA was melted. Voranol 220-260 was vacuum-loaded into the reactor. Molten TIPA was vacuum-loaded into the reactor, followed by Voranol 220-110N. The vacuum line was flushed with ethyl acetate, and the reactor contents were stirred at 75 RPM. Ethyl acetate was vacuum-loaded into the reactor. The reactor contents were cooled via a cooling jacket. After cooling, TDI was loaded into the reactor, and the vacuum line was flushed with ethyl acetate. Due to the exothermic nature of the reaction, the reactor contents were cooled to 75°C. The temperature in the reactor was maintained at 75°C with stirring for 4 hours. The reactor contents were then cooled to 60°C, and a mixture of defoamer and remaining ethyl acetate was vacuum-loaded into the reactor. The contents were then stirred for 30 minutes. The reactor was then cooled to 50°C, and reactant composition B was packaged for use.

[0103] Component B of Example 2

[0104]

[0105] To prepare reactant composition B of Example 2, TIPA was melted. Voranol 220-260 was vacuum-loaded into the reactor. Molten TIPA was vacuum-loaded into the reactor, followed by Voranol 220-110N. The vacuum line was flushed with ethyl acetate, and the reactor contents were stirred at 75 RPM. Ethyl acetate was vacuum-loaded into the reactor. The reactor contents were cooled via a cooling jacket. After cooling, TDI was loaded into the reactor, and the vacuum line was flushed with ethyl acetate. Due to the exothermic nature of the reaction, the reactor contents were cooled to 75°C. The temperature in the reactor was maintained at 75°C with stirring for 4 hours. The reactor contents were then cooled to 60°C, and a mixture of defoamer, cellulose acetate butyrate, modafloW, and the remaining ethyl acetate was vacuum-loaded into the reactor. The contents were then stirred at 60°C for 60 minutes. The reactor was then cooled to 50°C, and reactant composition B was packaged for use.

[0106] Use the following comparison example.

[0107] <![CDATA[ Comparative Examples ]]> <![CDATA[ product ]]> <![CDATA[ supplier ]]> <![CDATA[ Notes ]]> C3 1K OPV Flexo Coating Siegwerk single-component polyurethane C4 SQ 2K Gloss Coating Sun Chemical Two-component polyurethane C5 UV-cured varnish 002 Sericol Believed to be acrylic acid

[0108] In the scratch resistance test, a uniform, single-color ink is printed on an area of ​​the substrate, and this printed area is then tested. The result is the number of scratch cycles performed before any visible damage appears on the surface of the sample. The test is stopped at 50 cycles, even though the best samples do not show any damage at this point. The results are as follows:

[0109] <![CDATA[ Example ]]> <![CDATA[ Number of scratch cycles before damage ]]> 1 50 2 50 C3 30 C4 45 C5 20

[0110] The embodiments of the present invention demonstrate better scratch resistance than all comparative examples.

[0111] The following three different chemical reagents were used in the chemical resistance test:

[0112] "Cl" = liquid chlorine-containing disinfectant

[0113] "Cl / det" = a solution with the same "Cl" but with added detergent.

[0114] "liq" = Commercial liquid multi-purpose household cleaning solution

[0115] The following three different settling times were used: 0.5h, 4h, and 24h.

[0116] The results are as follows:

[0117] <![CDATA[ Cl ]]> <![CDATA[ Cl ]]> <![CDATA[ Cl ]]> <![CDATA[ Cl / det ]]> <![CDATA[ Cl / det ]]> <![CDATA[ Cl / det ]]> <![CDATA[ liq ]]> <![CDATA[ liq ]]> <![CDATA[ liq ]]> <![CDATA[ Example ]]> <![CDATA[ 0.5h ]]> <![CDATA[ 4h ]]> <![CDATA[ 24h ]]> <![CDATA[ 0.5h ]]> <![CDATA[ 4h ]]> <![CDATA[ 24h ]]> <![CDATA[ 0.5h ]]> <![CDATA[ 4h ]]> <![CDATA[ 24h ]]> 1 good good good good good good good good good 2 good good good good good good good good good C3 good Difference Difference good Difference Difference good Difference Difference C4 good Difference Difference good Difference Difference good Difference Difference C5 good medium Difference good medium Difference good medium Difference

[0118] At 0.5 hours, all embodiments showed good performance. At 4 hours and 24 hours, the embodiments of the present invention showed better chemical resistance than all comparative examples.

[0119] The temperature resistance test was performed as described above. The results are as follows:

[0120] <![CDATA[ Example ]]> <![CDATA[ Temperature (°C) ]]> 1 175 2 175 C3 125 C4 155 C5 135 Uncoated printed film 75

[0121] The embodiments of the present invention exhibit better temperature resistance than all comparative examples. The uncoated film at 75°C... ℃ The location shows damage; Comparative examples C3, C4, and C5 showed damage outside the range of 125°C to 155°C, while the embodiments of the present invention did not show damage before 175°C. It indicates that it is damaged.

[0122] In the gloss test, the results are the gloss observed at a 60-degree angle. The results are as follows:

[0123] <![CDATA[ Example ]]> <![CDATA[ Gloss (%) ]]> 1 77 2 82 C3 58 C4 72 C5 65 Uncoated printed film 41

[0124] The embodiments of the present invention exhibit better gloss than all comparative examples.

Claims

1. A method for preparing a coated printing substrate, the method comprising: (a) A printing substrate is provided, wherein the substrate includes a surface of one or more regions thereon on which an ink layer is present, wherein the ink comprises: (i) 10 wt% to 90 wt% of ethylene-acrylic acid copolymer, and (ii) one or more appearance additives, said appearance additives being selected from one or more pigments, one or more dyes, and mixtures thereof, and (iii) 0.5 wt% to 10 wt% of one or more conductive additives, (b) Combining component A and component B to form a urethane coating composition. Component A consists of the following: A polyisocyanate prepolymer composed of the reaction product of a first polyisocyanate monomer and a polyisocyanate multireactive compound; Solvents ranging from 20 wt% to 50 wt%; 0.1 wt% to 5 wt% of one or more fatty triglycerides; 0.1 wt% to 5 wt% of one or more wax esters; and Benzoyl chloride; Component B consists of the following: 20 wt% to 85 wt% of polyurethane polyols composed of the following: (i) the second polyisocyanate monomer; and (ii) Polyols selected from: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, triisopropanolamine, and combinations thereof. Solvents ranging from 10 wt% to 70 wt%; Defoamer; Optional 0.1 wt% to 5 wt% of one or more anti-caking agents; and One or more wetting agents, ranging from 0.05 wt% to 5 wt%. Components A and B comprise 100% by weight of the urethane coating composition. The urethane coating composition wherein the urethane coating composition has an isocyanate index greater than 0.9, and (c) Applying a layer of the urethane coating composition to the surface; The temperature resistance of the layer of the urethane coating composition is as follows: according to ASTM 1921, the layer of the urethane coating composition remains undamaged up to 175°C; and the gloss of the layer of the urethane coating composition is 77 to 82 according to ASTM 2457.

2. The method according to claim 1, wherein the polyurethane polyol comprises a reaction product of a polyisocyanate monomer and a polyol.

3. The method of claim 1, wherein the substrate comprises polyethylene.

4. The method according to claim 1, wherein the isocyanate multireactive compound comprises one or more polyether polyols, one or more polyester polyols, or mixtures thereof.

5. The method according to claim 1, wherein the urethane coating composition has an isocyanate index greater than 0.9 and less than or equal to 1.

6.

6. The method according to claim 1, wherein the polyol in component B is trimethylene glycol.

7. A coated printing substrate, said coated printing substrate being manufactured by the method according to claim 1.

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