Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/40—Layered products comprising a layer of synthetic resin comprising polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
  • C08L75/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

• the present invention relates to a urethane resin composition for forming a primer layer that can be removed from a substrate, a laminate using the urethane resin composition, packaging materials or electronic equipment that include the laminate, and a method for producing recycled substrates.
• the problem that the present invention aims to solve is to provide a urethane resin composition that will not peel off even with strongly alkaline substances under normal temperature conditions, but will produce a coating that can be removed from plastic substrates by treatment with warm alkaline water.
• the polyol (a) includes a polyester polyol (a1), R (HSP distance) represented by the following formula (1) is 9 or less, the urethane resin (A) has an ester bond group concentration of 3 mmol/g or more and 9 mmol/g or less, the acid value of the urethane resin (A) is 0 mgKOH/g or more and 15 mgKOH/g or less, the urethane resin (A) has a urea group concentration of 0.2 mmol/g or more and 2 mmol/g or less,
• a urethane resin composition wherein the content of diethylene glycol residues or ethylene glycol residues in the total glycol components of the polyester in the urethane
• the polyol (a) further contains a polyether polyol (a2), [1] The urethane resin composition according to any one of [1] to [4], wherein the urethane resin (A) is a reaction product of a polyester polyol (a1), a polyether polyol (a2), and a polyisocyanate (b). [6] The urethane resin composition according to [5], wherein the polyether polyol (a2) contains a polyethylene glycol component and/or a polypropylene glycol component.
• the laminate further includes a substrate (D) different from the substrate (C), The laminate according to any one of [12] to [14], wherein the substrate (D) is disposed on the surface of the printed layer opposite to the surface on which the substrate (C) is disposed, and the substrate (C), the primer layer, the printed layer, and the substrate (D) are laminated together.
• a method for producing a recycled substrate comprising treating the laminate according to [12] with an alkaline solution to remove the primer layer and the printed layer from the substrate (C), thereby obtaining a recycled substrate.
• a method for producing a recycled substrate comprising treating the laminate according to [11] with an alkaline solution to remove the primer layer, the printed layer, and/or the substrate (D) from the substrate (C), thereby obtaining a recycled substrate.
• the present invention provides a urethane resin composition that, under normal temperature conditions, is resistant to peeling even with strongly alkaline substances, but whose coating can be removed from plastic substrates by treatment with warm alkaline water.
• the urethane resin composition of the present invention contains at least a urethane resin (A) formed from a reaction product of a polyol (a) and a polyisocyanate (b), and an organic solvent (B).
• the urethane resin (A) is a general term for a polymeric compound having a urethane bond (—NHCOO—).
• the urethane resin (A) is a reaction product obtained by reacting (crosslinking/curing reaction) a polyol (a) with a polyisocyanate (b), and the polyol (a) essentially contains a polyester polyol (a1).
• the polyol (a) may contain, in addition to the polyester polyol (a1), a polyether polyol (a2) and/or other polyol (a3), as necessary.
• the urethane resin (A) may contain, in addition to the polyester polyol (a1) and the polyisocyanate (b), a polyether polyol (a2) and/or another polyol (a3) as reaction raw materials, or may be a reaction product of the polyester polyol (a1), the polyisocyanate (b), and the polyether polyol (a2) and/or another polyol (a3).
• reaction raw material refers to a compound that is used to obtain a target compound through a chemical reaction such as synthesis or decomposition and that partially constitutes the chemical structure of the target compound, and excludes substances that serve as chemical reaction aids, such as solvents and catalysts.
• reaction raw materials include polyester polyol (a1), polyisocyanate (b), dicarboxylic acid (a1-1), polyvalent hydroxyl group compound (a1-2), polyether polyol (a2), and other polyols (a3).
• reaction raw materials include polyester polyol (a1), polyisocyanate (b), dicarboxylic acid (a1-1), polyvalent hydroxyl group compound (a1-2), polyether polyol (a2), and other polyols (a3).
• residue refers to a partial structure in a product compound formed by a reaction or polymerization other than the structure of the chemical bond involved in the reaction or polymerization.
• the urethane resin (A) of the present invention has a polyester polyol (a1) residue (also referred to as the polyester polyol (a1) component) and a polyisocyanate (b) residue (also referred to as the polyisocyanate (b) component), and optionally further has a polyether polyol (a2) residue and another polyol (a3) residue.
• the content of diethylene glycol residues or ethylene glycol residues in the total glycol components of the polyester in the urethane resin (A) is 50% by weight or more.
• the coating is less susceptible to peeling even with strongly alkaline substances, and the coating is more likely to be detached from the plastic substrate by treatment with warm alkaline water.
• the content of isophorone diisocyanate residues in the polyisocyanate component (b) in the urethane resin (A) is 50% by weight or more.
• the total concentration of urethane groups and urea groups in the urethane resin (A) is preferably 1.0 mmol/g or more and 3.0 mmol/g or less.
• polyester polyol (a1) can be produced, for example, by esterifying a dicarboxylic acid (a1-1) with a polyhydric hydroxyl compound (a1-2).
• dicarboxylic acids (a1-1) that can be used when producing polyester polyol (a1) include dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-P,P'-dicarboxylic acid, as well as their acid anhydrides or ester-forming derivatives; aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and their ester-forming derivatives; and sulfonic acid group-containing aromatic dicarboxylic acids such as 5-sulfoisophthalic acid and their ester-forming derivatives.
• dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,4-naphthalenedicarbox
• aliphatic carboxylic acids and alicyclic carboxylic acids can also be used in combination.
• examples include aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, maleic anhydride, and fumaric acid, and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, as well as their anhydrides and ester-forming derivatives. These may be used alone or in combination of two or more.
• polyhydric hydroxyl group compound (a1-2) examples include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, and neopentyl glycol.
• dicarboxylic acid (a1-1) and polyhydroxyl compound (a1-2) can be reacted, if necessary in the presence of a catalyst, under atmospheric or reduced pressure in a reaction vessel purged with an inert gas such as nitrogen.
• the reaction is preferably carried out at a temperature in the range of 100°C to 300°C.
• the catalyst may be, for example, an acetate salt of an alkali metal or alkaline earth metal, or a compound containing zinc, manganese, cobalt, antimony, germanium, titanium, tin, zirconium, etc.
• the polyester polyol (a1) component is preferably contained in an amount ranging from 50% by mass to 80% by mass relative to the polyurethane resin. If the polyester polyol (a1) component is less than 50% by mass relative to 100% by mass of polyurethane resin, the solvent solubility of the polyurethane resin will decrease. Furthermore, it will be difficult to remove the polyurethane resin from the plastic substrate by treatment with warm alkaline water. Furthermore, if it exceeds 80% by mass, the polyurethane resin film will tend to become brittle, reducing the blocking resistance of the ink film.
• polyether polyol (a2) As the polyether polyol (a2), various known polyether polyols commonly used in the production of polyurethane resins can be used, and one or more of them may be used in combination. Examples include polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, etc. Specifically, polyethylene glycol is preferred, and known general-purpose polyether polyols such as polypropylene glycol and polytetramethylene glycol may also be used, or a copolymer of polyethylene glycol and polypropylene glycol may also be used. By containing the polyether polyol (a2), adhesion to films in particular is significantly improved, resulting in excellent blocking resistance and laminate strength.
• the polyether polyol (a2) preferably has a number average molecular weight of 100 or more and 3,500 or less. If the number average molecular weight of the polyether polyol is less than 100, the polyurethane resin (A) film tends to become hard, resulting in reduced adhesion to plastic films. If the number average molecular weight is greater than 3,500, the polyurethane resin film tends to become brittle, resulting in reduced blocking resistance of the ink film. From the same perspective, the number average molecular weight of the polyether polyol (a2) is more preferably 600 or more, even more preferably 1,000 or more, and even more preferably 2,000 or more.
• the same polyols as those used for the polyhydric hydroxyl compound (a1-2) can be used, and for example, relatively low molecular weight polyols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, and neopentyl glycol can be used.
• the other polyol (a3) component is preferably contained in the range of 0% by mass to 20% by mass relative to the polyurethane resin. If the other polyol (a3) component exceeds 20% by mass relative to 100% by mass of polyurethane resin, the polyurethane resin film tends to harden, reducing adhesion to plastic films.
• polyisocyanate (b) that reacts with the polyol (a1) to form the urethane resin (A)
• aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate
• aliphatic or alicyclic structure-containing diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate, which may be used alone or in combination of two or more.
• the organic solvent (B) that can be used when producing the urethane resin (A) includes, for example, ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide, N-methylpyrrolidone, etc., which can be used alone or in combination of two or more.
• Examples of compounds that can be used include ethylenetriamine, dipropylenetriamine, and triethylenetetramine; hydrazine, N,N'-dimethylhydrazine, and 1,6-hexamethylenebishydrazine; succinic dihydrazide, adipic dihydrazide, glutaric dihydrazide, sebacic dihydrazide, and isophthalic dihydrazide; ⁇ -semicarbazidopropionic hydrazide, 3-semicarbazidopropylcarbazate, and semicarbazido-3-semicarbazidomethyl-3,5,5-trimethylcyclohexane, with ethylenediamine being preferred.
• R (HSP distance) is calculated from the dispersion force term, polarity term, and hydrogen bond term in the Hansen solubility parameters of the polyester polyol (a1) and the organic solvent (B) according to the following formula (1).
• R (HSP distance) is an index of the solubility of the organic solvent (B) in the polyester polyol (a1); the lower the value, the better the solubility can be expected; in the present invention, R is 9 or less.
• R (HSP distance) is preferably 8 or less, and more preferably 7 or less.
• R (HSP distance) is preferably 3 or more, and more preferably 5 or more. Among these, R (HSP distance) is preferably 3 or more and 8 or less, and more preferably 5 or more and 7 or less.
• the ester bond group concentration of the urethane resin (A) is 3 mmol/g or more and 9 mmol/g or less.
• the concentration of the ester bond group can be determined by calculating the number of moles of the ester bond group contained in 1 g of the urethane resin (A).
• the ester bond group concentration is preferably 4 mmol/g or more, and more preferably 5 mmol/g or more, from the viewpoint of improving the substrate adhesion and deinking ability of the resulting primer layer, and is preferably 8 mmol/g or less, and more preferably 7 mmol/g or less, from the viewpoint of good blocking resistance of the primer layer.
• the acid value of the urethane resin (A) is 0 mgKOH/g or more and 15 mgKOH/g or less.
• the acid value is the amount of acid in 1 g of resin calculated by titrating the acid with an alkali, converted into mg of potassium hydroxide, and is a value measured in accordance with JIS K0070. If the acid value is 0 mgKOH/g or more, the aqueous dispersion stability can be improved, and it is preferably 7 mgKOH/g or more, and more preferably 8 mgKOH/g or more.
• the acid value is 15 mgKOH/g or less, the adhesion to the polyester substrate can be ensured well, and it is preferably 13 mgKOH/g or less, and more preferably 10 mgKOH/g or less. Furthermore, from the viewpoint of resin viscosity and storage stability, it is preferable that the acid value is 0 mgKOH/g.
• the urea group concentration of the urethane resin (A) is 0.2 mmol/g or more and 2 mmol/g or less.
• the urea group concentration is the value obtained by dividing the weight of the diamine contained in 1 g of the urethane resin by the NCO equivalent weight of the constituting diamine.
• a urea group concentration of 0.2 mmol/g or more can improve the durability of the final urethane resin composition, and is preferably 0.3 mmol/g or more, and more preferably 0.6 mmol/g or more.
• a urea group concentration of 2 mmol/g or less can ensure organic solvent solubility, and is preferably 1.7 mmol/g or less, and more preferably 1.5 mmol/g or less.
• the urea group concentration is preferably 0.3 mmol/g or more and 1.7 mmol/g or less, and more preferably 0.6 mmol/g or more and 1.5 mmol/g or less.
• the content of diethylene glycol residues or ethylene glycol residues in the total polyol (a) component of the polyester in the urethane resin (A) is 50% by weight or more.
• the content of diethylene glycol residues or ethylene glycol residues can be calculated from the composition of the raw materials used in preparing polyester polyol (a1), which is the raw material for urethane resin (A), and is the weight of diethylene glycol or ethylene glycol in polyester polyol (a1) divided by the weight of all glycols, expressed as a percentage.
• the content of isophorone diisocyanate is 50% by weight or more, the solubility in organic solvents can be improved, and 70% by weight or more is more preferable, and 80% by weight or more is even more preferable.
• the content of isophorone diisocyanate may be 100% by weight, 95% by weight or less, or 90% by weight or less.
• the content of isophorone diisocyanate is more preferably 70% by weight or more but 95% by weight or less, and particularly preferably 80% by weight or more but 90% by weight or less.
• the total concentration of urethane groups and urea groups in the urethane resin (A) is preferably 1.0 mmol/g or more and 3.0 mmol/g or less.
• the total concentration of urethane groups and urea groups is the value obtained by dividing the weight of diisocyanate contained in 1 g of urethane resin (A) by the NCO equivalent weight of the constituting diisocyanate. If the urethane group and urea group concentrations are 1.0 mmol/g or more, the durability of the finally obtained urethane resin composition can be improved, with 1.2 mmol/g or more being more preferred, and 1.5 mmol/g or more being even more preferred.
• the content of ethyl acetate in organic solvent (B), which serves as a solvent for urethane resin (A), is preferably 20% by weight or more and 100% by weight or less, and the content of isopropyl alcohol is preferably 0% by weight or more and 80% by weight or less.
• the content of ethyl acetate is more preferably 60% by weight or more and 100% by weight or less, and the content of isopropyl alcohol is more preferably 0% by weight or more and 40% by weight or less.
• the content of ethyl acetate is more preferably 70% by weight or more, and even more preferably 80% by weight or more.
• the urethane resin composition of the present invention preferably contains urethane resin (A) in the range of 5% by mass to 50% by mass, and more preferably 10% by mass to 40% by mass, based on the total amount of the urethane resin composition. Furthermore, the organic solvent (B) is preferably contained in the range of 50% by mass to 95% by mass, and more preferably 60% by mass to 90% by mass, based on the total amount of the urethane resin composition.
• the urethane resin composition of the present invention may contain various additives, such as a film-forming aid, a curing accelerator, a plasticizer, an antistatic agent, a wax, a light stabilizer, a flow modifier, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a photocatalytic compound, an inorganic pigment, an organic pigment, or an extender pigment, as necessary.
• additives such as a film-forming aid, a curing accelerator, a plasticizer, an antistatic agent, a wax, a light stabilizer, a flow modifier, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a photocatalytic compound, an inorganic pigment, an organic pigment, or an extender pigment, as necessary.
• the ink When printing, the ink is diluted with a diluting solvent, for example, a mixture of an acetate ester-based organic solvent such as ethyl acetate or butyl acetate with an alcohol-based organic solvent such as ethyl alcohol, isopropyl alcohol or normal propyl alcohol, to a viscosity and concentration suitable for various printing methods such as gravure printing or flexographic printing, and then supplied to each printing unit either alone or in a mixture.
• a diluting solvent for example, a mixture of an acetate ester-based organic solvent such as ethyl acetate or butyl acetate with an alcohol-based organic solvent such as ethyl alcohol, isopropyl alcohol or normal propyl alcohol
• the present invention also provides a laminate having a primer layer formed using the urethane resin composition of the present invention.
• the laminate of the present invention has a primer layer formed on a substrate by coating the urethane resin composition of the present invention, and further has a printed layer formed on the primer layer by printing a printing ink composition.
• the laminate of the present invention is not limited to a laminate having a surface printing type structure in which a printed layer is formed on the surface of the laminate, as in the above-mentioned embodiment (1-A), but also encompasses a laminate having a laminate type structure in which a coating film (various layers or films) is further formed on the printed layer.
• the laminate of the present invention also covers laminates having a laminate-type structure in which another substrate (substrate (D)) is placed on the side opposite to the side on which the substrate (substrate (C)) is placed relative to the printed layer, and the substrate (C), primer layer, printed layer, and substrate (D) are laminated together.
• Examples of the laminate having a laminate type structure include the laminates of the following embodiments.
• a primer layer may be applied to both sides of the film positioned as the intermediate layer.
• (2-7) Base film 1/primer layer/printing layer/adhesive layer 1/primer layer/transparent vapor-deposited stretched film/primer layer/adhesive layer 2/sealant film;
• the primer layer on the surface of the vapor-deposited film (whether transparent or metallic, stretched or unstretched) facing the printed layer may be removed.
• the vapor-deposited layer may be dissolved in an alkaline solution, allowing the primer layer formed on one surface of the vapor-deposited film to be removed.
• one surface of the vapor-deposited film is located on the surface of the laminate, so the primer layer facing the other inner surface is removed.
• the laminated body having a laminate type structure may have a laminate type structure in which a coating film (various layers or films) is further formed on the printed layer by extrusion lamination.
• the laminate of the present invention also covers laminates having a laminate-type structure in which an extrusion laminate layer is placed on the side opposite to the side on which the substrate (substrate (C)) is placed relative to the printed layer, and the substrate (C), primer layer, printed layer, and extrusion laminate layer are laminated together.
• Examples of the laminate having an extrusion laminate type structure include the laminates of the following embodiments.
• the substrate film 1 corresponds to the substrate (C) of the present invention.
• other layers such as a sealant layer may be disposed on the surface of the extrusion laminate layer opposite to the surface on which the base film 1 is provided.
• the structures of the other layers are not limited to the following structures (5-1-1) to (5-1-6) and can be appropriately designed depending on the required properties. The following is an example of a configuration in which other layers are provided in the configuration of (5-1) above. Similar configurations are also possible for (5-2) and (5-3) above.
• Base film 1/primer layer/printed layer/extrusion laminate anchor layer/extrusion laminate layer/adhesive layer 1/sealant film (5-1-2) Base film 1/primer layer/printed layer/extrusion laminate anchor layer/extrusion laminate layer/adhesive layer 1/metal layer/adhesive layer 2/sealant film (5-1-3) Base film 1/primer layer/printed layer/extrusion laminate anchor layer/extrusion laminate layer/primer layer/adhesive layer 1/sealant film (5-1-4) Base film 1/plastic Mater layer / printed layer / extrusion laminate anchor layer / extrusion laminate layer / primer layer / adhesive layer 1 / metal layer / adhesive layer 2 / sealant film (5-1-5) Base film 1 / primer layer / printed layer / extrusion laminate anchor layer / extrusion laminate layer / primer layer / adhesive layer 1 / primer layer / sealant film (5-1-6) Base film 1 / primer layer / printed
• the primer layer may be formed by an in-line coating method in which a urethane resin composition is applied during the film stretching process and then a further stretching process is performed, or the primer layer may be formed by an offline coating method in which a urethane resin composition is applied and dried after the film stretching process to form the primer layer.
• the printed layer is, for example, a printed layer formed with printing ink.
• Examples of the printed layer include a printed layer formed with printing ink containing a colored pigment or a white pigment as a colorant.
• the printing method for the printed layer is not particularly limited, and the printed layer can be formed by various printing methods such as gravure printing, flexographic printing, offset printing, inkjet printing, and screen printing.
• the printing ink can be an ink suitable for the various printing methods, and may be a solvent-based ink or a water-based ink. UV-curable or EB-curable ink may also be used.
• the base film 1 examples include an OPP film (a polypropylene film, for example, a biaxially oriented polypropylene film), a PET film (a polyethylene terephthalate film, for example, a biaxially oriented polyethylene terephthalate film), and a nylon film.
• the base film 1 may be coated to improve gas barrier properties or ink receptivity when a printing layer is provided.
• Examples of commercially available coated base films 1 include a K-OPP film and a K-PET film.
• the sealant film include a CPP film (unstretched polypropylene film) and an LLDPE film (linear low-density polyethylene resin film).
• a VM-CPP film obtained by vapor-depositing a metal such as aluminum onto a CPP film can be used.
• a metal-deposited stretched film a VM-OPP film obtained by depositing a metal such as aluminum on an OPP film can be used.
• the transparent vapor-deposited stretched film include films obtained by depositing silica or alumina on OPP films, PET films, nylon films, etc.
• a film having a coating applied to the vapor-deposited layer may also be used.
• the metal layer may be an aluminum foil or the like.
• the base film 2 may be a nylon film or the like.
• the adhesive layer can be formed using a known adhesive for film lamination.
• a known anchor coating agent for extrusion lamination can be used as an adhesive aid.
• the use of a material having gas barrier properties for these adhesives or anchor coating agents can result in a laminate with particularly excellent barrier properties.
• Particularly preferred adhesives with excellent gas barrier properties are those that satisfy at least one of the following conditions: an oxygen barrier property of 300 cc/ m2 /day/atm or less, or a water vapor barrier property of 120 g/ m2 /day or less, of a cured coating film of the adhesive applied at 3 g/m2 (solid content).
• the extrusion laminate layer can be made of a known thermoplastic resin, such as a polyolefin resin such as a polyethylene resin or a polypropylene resin, but is not limited to these materials.
• Various known anchor coating agents can be used for the anchor layer for extrusion lamination. Examples include, but are not limited to, isocyanate-based and amine polymer-based materials.
• the “anchor layer for extrusion lamination” may also be formed using the urethane resin composition of the present invention. Forming the "anchor layer for extrusion lamination” using the urethane resin composition of the present invention improves adhesion to the extrusion laminate layer and also improves the deinking properties of the extrusion laminate layer during peeling treatment.
• the urethane resin composition of the present invention can be suitably used for packaging materials or electronic equipment as a surface treatment agent (primer coating agent) for substrates in molded products having an overprinted layer including a printed layer, such as electronic equipment, building materials, textiles and leather, home appliances, vehicles such as cars and airplanes, furniture, office supplies, play equipment, sporting goods, or molded parts thereof. Therefore, laminates having a primer layer formed from the urethane resin composition of the present invention can be applied to various molded products such as electronic equipment, building materials, textiles and leather, home appliances, vehicles such as cars and airplanes, furniture, office supplies, play equipment, sporting goods, and molded parts for these goods.
• a laminate having a primer layer formed from the urethane resin composition of the present invention can also be used in packaging materials (more specifically, multi-layer packaging materials).
• packaging materials more specifically, multi-layer packaging materials
• it can also be used as a multi-layer packaging material.
• the layer structure can be changed depending on the contents, the environment of use, and the form of use.
• the packaging material for example, the contents are filled through the opening, and the opening is then heat-sealed to produce a product using the packaging material formed from the laminate of the present invention.
• the uses of the packaging material are not particularly limited, but it can be used as a packaging material for food, medicine, sanitary products, cosmetics, electronic equipment, building materials, industrial materials, etc., and is particularly applicable to electronic equipment.
• the primer layer formed from the urethane resin composition of the present invention also has good adhesion to the substrate, and the laminate of the present invention has excellent adhesion between the substrate and the printed layer. Furthermore, the primer layer of the laminate of the present invention can be removed in a simple manner by using a warm alkaline solution, and the substrate and the printing layer can be easily peeled off. However, the primer layer of the laminate of the present invention will not be peeled off even when an alkaline solution is applied under temperature conditions that are normally used. Therefore, under temperature conditions that are normally used, even if an alkaline solution is unintentionally attached, the laminate can be used safely without worrying about peeling.
• the primer layer can be easily removed by application of a warm alkaline solution, not only for laminates having a surface-printed type structure such as in the above-mentioned (1-A) embodiment, but also for laminates having a laminate-type structure such as in the above-mentioned (1-1) to (4-3-2-7) embodiments, and the substrate and printed layer can be easily peeled off.
• a primer layer formed using the urethane resin composition containing the crosslinking agent has excellent film strength and good film-forming properties, but on the other hand, a primer layer formed using the urethane resin composition of the present invention can maintain the high deinking performance that is the objective of the present invention, even if it contains a crosslinking agent.
• the laminate of the present invention produced using a crosslinking agent can be made to be excellent in both film-forming properties and removability.
• the primer layer can be removed from the substrate by immersing it in a warm alkaline solution.
• the alkaline substance used in the alkaline aqueous solution for removing the primer layer in the present invention is not particularly limited, and examples thereof include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH) 2 ), and ammonia.
• NaOH or KOH is used.
• NaOH, KOH, ammonia, or the like is uniformly dissolved or dispersed in water, and the concentration or pH is appropriately adjusted to a specified level.
• the primer layer removal conditions include immersing the laminate in an alkaline aqueous solution having a pH of 11 or higher or a concentration of 0.5% by mass to 3.0% by mass at 10°C to 100°C for 30 minutes, followed by rinsing and drying to remove 90% or more of the primer layer.
• the pH is preferably 11.0 or higher, more preferably 13.0 or higher.
• the concentration of the aqueous solution is preferably 0.5% by mass to 3.0% by mass, and more preferably 1.0% by mass to 2.5% by mass.
• the immersion temperature is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower.
• the immersion temperature is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher.
• the immersion time is within 60 minutes, more preferably within 30 minutes, and even more preferably within 20 minutes.
• the immersion time is longer than that of embodiment (1-A), but it is more preferable that delamination proceeds in a short time.
• the immersion time is preferably within 24 hours, more preferably within 12 hours, and even more preferably within 6 hours.
• the primer layer can be removed by immersing the laminate in a warm alkaline solution. That is, according to the present invention, the laminate is treated with a warm alkaline solution to remove the printed layer together with the primer layer from the substrate (C), thereby obtaining a recycled substrate (C).
• the laminate is treated with a warm alkaline solution to remove the printed layer and/or substrate (D) together with the primer layer from the substrate (C), thereby obtaining a recycled substrate (C), or a recycled substrate (C) and a recycled substrate (D) or a sealant film.
• a represents the number of moles of carboxylic acid residues in 1 g of polyester polyol (a1).
• polyester polyol (a1) The structure of polyester polyol (a1) was expressed in SMILES, and the three HSP parameters of polyester polyol (a1), namely, the dispersion force term ( ⁇ D 1 ), polar term ( ⁇ P 1 ), and hydrogen bond term ( ⁇ H 1 ) in the Hansen solubility parameter, were calculated using HSP calculation software HSP-iP. When two or more polyols were used, the product of each calculated HSP value and the percentage of each polyol was used.
• ⁇ Acid value (mgKOH/g)> The number of COOH groups contained in 1 g of urethane resin is determined in mg of KOH required when titrated by the potassium hydroxide method.
• ⁇ Urea group concentration> The weight of the diamine residue contained in 1 g of the urethane resin is divided by the NCO equivalent weight of the constituting diamine to obtain the value.
• Polyol The compositions and physical properties of polyols 1 to 6 used in the examples and comparative examples are shown in Table 1 below.
• AA adipic acid
• NPG neopentyl glycol
• DEG diethylene glycol
• EG ethylene glycol.
• Polyol 1 in Table 1 indicates that a polyester polyol was produced by mixing and reacting 0.55 g of adipic acid and 0.45 g of diethylene glycol.
• the raw material compositions of Polyols 2 to 4 and 6 are also shown in Table 1. The following products were used as raw materials for polyols 5, 7 and 8, which are non-polyester polyols.
• Urethane resins 2 to 14 were prepared in the same manner as above, except that the composition of urethane resin 1 was changed as shown in Table 2 below.
• the compositions and physical properties of polyurethane resins 2 to 14 are shown in Tables 2 and 3.
• the ester bond group concentrations shown in Table 2 were determined as follows.
• the urethane resin 1 will be used as an example.
• the concentration of ester bond groups in 1 g of polyol 1 is calculated.
• a 0.55 (adipic acid content of polyol 1)/146 (molecular weight of adipic acid)
• the total concentration of urethane groups and urea groups shown in Table 2 was determined as follows.
• R (HSP distance) shown in Table 3 was calculated as follows.
• the urethane resin 1 will be used as an example.
• each polyol in the urethane resin 1 is represented by the following SMILES.
• Polyol 1 O ⁇ C(CCCCC( ⁇ O)OCCOCCX)OX
• Polyol 5 XOCCX
• HSP-iP HSP calculation software
• Example 1 The laminate 1 used in Example 1 was produced as follows.
• As the base film 1 an OPP base film ("FOR 20 ⁇ m" manufactured by Futamura Chemical Co., Ltd.) was used.
• For the primer layer urethane resin 1 was used, and the urethane resin composition contained a crosslinking agent.
• the primer layer containing a crosslinking agent was prepared as follows: 100 parts of urethane resin 1 was mixed with 9 parts of Bayhydur Ultra 3100 manufactured by Covestro, and then diluted with ethyl acetate to a solid content of 10%.
• the urethane resin composition obtained above was printed on a substrate film 1 that had been subjected to a corona discharge treatment on one side using a gravure printing machine (manufactured by DIC Engineering Corporation) equipped with a gravure plate having a plate depth of 22 ⁇ m, followed by drying at 100° C. for 10 minutes and then leaving at room temperature for at least one day.
• the ink layer was prepared as follows: Laminating ink "Finart (manufactured by DIC Corporation)" was diluted with a mixed organic solvent in the same ratio as the ink, and diluted to 16 seconds using a Rigo Zahn Cup No. 3.
• Laminates 2 to 38 were produced in the same manner except that the structure of Laminate 1 was changed as shown in Tables 4 to 10 below.
• the structures of laminates 2 to 38 are shown in Tables 4 to 10.
• Comparative laminates 1 to 12 were prepared in the same manner except that the structure of laminate 1 was changed as shown in Table 11 or Table 12 below.
• the structures of comparative laminates 1 to 12 are shown in Tables 11 and 12.
• PU resin means polyurethane resin.
• the base film 1 is PET
• the base film is "E5102 12 ⁇ m" manufactured by Toyobo Co., Ltd.
• the primer layer did not contain a crosslinking agent
• the primer layer was formed using a urethane resin composition diluted with ethyl acetate to a solids content of 10%.
• the urethane resin composition was applied using a gravure printing machine to form the primer layer as described above in the preparation of Laminate 1.
• the transparent vapor-deposited film 1 used in Comparative Example 12 was an alumina-deposited transparent PET film IB-PET-PUB (thickness: 12 ⁇ m) manufactured by Dai Nippon Printing Co., Ltd.
• the laminate 1' used in Example 1 was produced as follows.
• As the base film 1 an OPP base film ("FOR 20 ⁇ m" manufactured by Futamura Chemical Co., Ltd.) was used.
• For the primer layer urethane resin 1 was used, and the urethane resin composition contained a crosslinking agent.
• the primer layer containing a crosslinking agent was prepared as follows: 100 parts of urethane resin 1 was mixed with 9 parts of Bayhydur Ultra 3100 manufactured by Covestro, and then diluted with ethyl acetate to a solid content of 10%.
• the urethane resin composition obtained above was printed on a substrate film 1 that had been subjected to a corona discharge treatment on one side using a gravure printing machine (manufactured by DIC Engineering Corporation) equipped with a gravure plate having a plate depth of 22 ⁇ m, followed by drying at 100° C. for 10 minutes and then leaving at room temperature for at least one day.
• the ink layer was prepared as follows: Laminating ink "Finart (manufactured by DIC Corporation)" was diluted with a mixed organic solvent in the same ratio as the ink, and diluted to 16 seconds using a Rigo Zahn Cup No. 3.
• Laminates 2' to 38' were prepared in the same manner as above except that the structure of laminate 1' was changed as shown in Tables 4 to 10 below. The structures of the laminates 2' to 38' are shown in Tables 4 to 10.
• Comparative laminates 1' to 12' were prepared in the same manner except that the structure of laminate 1' was changed as shown in Tables 11 and 12 below.
• the structures of comparative laminates 1' to 12' are shown in Tables 11 and 12.
• the primer layer of a laminate having a primer layer formed from the urethane resin composition of the present invention could be easily removed by using an alkaline solution at temperatures of 85° C. and 55° C.
• the primer layer was not removed by the alkaline solution at a temperature of 25° C.
• the laminate of the present invention has a laminate-type structure in which a plurality of layers are stacked, the primer layer can be removed by a warm alkaline solution.
• the present invention provides a urethane resin composition that, although not stripped even by strong alkaline substances under normal temperature conditions, can produce a coating that can be removed from plastic substrates by treatment with warm alkaline water.

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