Printing ink, method for manufacturing printed matter, and printed matter

Abstract

Disclosed is a printing ink including a fixing agent including a peptide polymer (having a polypeptide chain), a liquid medium, and a colorant. Also disclosed is a method of manufacturing a printed matter, the method comprising: a step of forming a film containing a printing ink on a substrate by a printing process; and removing the solvent from the film to form a printed film containing the fixing agent and the coloring agent. The polypeptide chain may also include an artificial protein.

Description

Technical Field

[0001] This disclosure relates to printing inks, methods of manufacturing printed matter, and printed matter. Background Technology

[0002] A general method for manufacturing printed matter involves forming a printed film on various substrates, such as paper, using printing inks containing colorants and fixers. Fixers are components used to fix colorants onto the substrate and mostly contain synthetic resins (e.g., Patent Document 1). Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2008-266494 Patent Document 2: International Publication No. 2021 / 187502 Summary of the Invention The problem that the invention aims to solve

[0004] This disclosure relates to a printing ink capable of forming a biodegradable printing film. Solution for solving the problem

[0005] This disclosure includes the following: [1] A printing ink comprising: a fixer containing a peptide polymer (having polypeptide chains), a liquid medium, and a colorant. [2] According to the printing ink described in [1], the polypeptide chain comprises an artificial protein. [3] According to the printing ink described in [1] or [2], the peptide polymer further has a modifying group that binds to the polypeptide chain. [4] The printing ink according to any one of [1] to [3], wherein the peptide polymer is a block copolymer, the block copolymer comprising a first segment containing the polypeptide chain and a second segment having a plasticizing function on the polypeptide chain. [5] The printing ink according to any one of [1] to [4], wherein the peptide polymer is a block copolymer comprising a first segment and a second segment, wherein the first segment contains the polypeptide chain, and the second segment comprises at least one selected from the group consisting of polyether, polyester, polycarbonate, polyamide and polyol groups. [6] The printing ink according to any one of [1] to [5], wherein at least one of the fixer or the colorant is dissolved in the liquid medium. [7] The printing ink according to any one of [1] to [5], wherein at least one of the fixer or the colorant is dispersed in the liquid medium. [8] A method for manufacturing printed matter includes: a step of forming a film comprising any one of the printing inks described in [1] to [7] on a substrate by a printing process; and The process of removing the liquid medium from the film to form a printing film containing the fixer and the colorant. [9] According to the method described in [8], the substrate is a fiber aggregate, paper, plastic parts, metal parts, ceramics, glass parts, wooden parts, or food.

[10] A printed article includes a substrate and a printing film disposed on the substrate; The printed film includes: a fixer containing a peptide polymer (having polypeptide chains) and a colorant.

[11] According to

[10] the printed matter, wherein the substrate is a fibrous aggregate, paper, plastic parts, metal parts, ceramics, glass parts, wooden parts or food. Invention Effects

[0006] It can form a biodegradable printing film. When manufacturing printed materials with a biodegradable substrate, it can effectively inhibit the decline in the biodegradability of the printed materials. Attached Figure Description

[0007] Figure 1 It's a photograph of a printed item. Figure 2 It's a photograph of a bent printed material. Figure 3 It's a photograph of a bent printed material. Figure 4 These are photos of printed materials after an ironing test. Detailed Implementation

[0008] This invention is not limited to the following examples.

[0009] An example of printing inks includes: a fixer containing peptide polymers (having polypeptide chains), a liquid medium, and a colorant. The fixer can be dissolved or dispersed in the liquid medium. Printing inks can be used to form a printed film on a substrate through a printing process. That is, printing inks can be used to manufacture printed matter having a substrate and a printed film.

[0010] The peptide polymer constituting the fixing agent can be a polymer containing only polypeptide chains (polymers of amino acids), or a polymer that also includes other molecular groups (molecules) bound to the polypeptide chains and / or modifying groups. The fixing agent may contain only peptide polymers, or it may contain other components (polymers).

[0011] The polypeptide chain can be a protein. The protein that is the polypeptide chain can be a natural protein or an artificial protein. In this specification, a natural protein is a protein having the same amino acid sequence as a protein of natural origin; while an artificial protein is a protein having an amino acid sequence different from that of a protein of natural origin.

[0012] Peptide chains can be hydrophobic. Hydrophobic peptide chains help improve the water resistance of printed films. The hydrophobicity of a peptide chain can be evaluated using the average hydrophilicity-hydrophobicity index (HEPAI: a hydrophobicity index). For example, the average hydrophilicity-hydrophobicity index of a hydrophobic peptide chain can be above 0.00, 0.10, 0.20, 0.22, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, or 0.70. The average hydrophilicity-hydrophobicity index of a hydrophobic peptide chain can be below 1.00 or below 0.7. The average hydrophobicity index of the hydrophobic polypeptide chain can be, for example, greater than 0.00, greater than 0.10, greater than 0.20, greater than 0.22, greater than 0.25, greater than 0.30, greater than 0.35, greater than 0.40, greater than 0.45, greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, or greater than 0.70, and less than 1.00.

[0013] The average hydrophobicity index (HI) of a polypeptide chain or protein, and the HI of repetitive sequence units as described below, are obtained using recognized hydrophobicity indices of amino acid residues according to accepted methods. Recognized hydrophobicity indices of amino acid residues are shown in Table 1. The hydrophobicity (HI) value can be calculated, for example, according to the method described in Kyte J and Doolittle R (1982), "A simple method for displaying the hydropathic character of a protein," J. Mol. Biol., 157, pp. 105-132.

[0014] [Table 1] amino acids HI amino acids HI Isoleucine (Ile) 4.5 Tryptophan (Trp) -0.9 Valine 4.2 Tyrosine (Tyr) -1.3 Leucine (Leu) 3.8 Proline (Pro) -1.6 Phenylalanine (Phe) 2.8 Histidine (His) -3.2 Cysteine ​​(Cys) 2.5 Asparagine (Asn) -3.5 Methionine (Met) 1.9 Aspartic acid (Asp) -3.5 Alanine (Ala) 1.8 Glutamine (Gln) -3.5 Glycine (Gly) -0.4 Glutamic acid (Glu) -3.5 Threonine (Thr) -0.7 Lysine (Lys) -3.9 Serine -0.8 Arginine (Arg) -4.5

[0015] From the perspective of improving the strength of the printed film formed by printing ink, the alanine residue content in the polypeptide chain or protein can be, for example, 10–40%, 12–40%, 15–40%, 18–40%, 20–40%, or 22–40%. The glycine residue content in the polypeptide chain or protein can be, for example, 10–55%, 11–55%, 13–55%, 15–55%, 18–55%, 20–55%, 22–55%, or 25–55%.

[0016] In this specification, "alanine residue content" refers to the value expressed by the following formula. Alanine residue content = (Number of alanine residues in the polypeptide / Total number of amino acid residues in the polypeptide) × 100 (%) The contents of glycine residues, serine residues, threonine residues, proline residues, and tyrosine residues have the same meaning as replacing alanine residues with glycine residues, serine residues, threonine residues, proline residues, and tyrosine residues, respectively, in the above formulas.

[0017] In any 20 consecutive amino acid residues in a polypeptide chain or protein, the total content of proline residues, threonine residues, and tyrosine residues can be 5% or more, exceeding 5.5%, 6% or more, exceeding 6.5%, 7% or more, exceeding 7.5%, 8% or more, exceeding 8.5%, 9% or more, 10% or more, or 15% or more, or less than 50%, less than 40%, less than 30%, or less than 20%. In any 20 consecutive amino acid residues in a polypeptide chain or protein, the total content of proline residues, threonine residues, and tyrosine residues can be 5% or more, and less than 50%, less than 40%, less than 30%, or less than 20%.

[0018] In polypeptide chains or proteins, the combined content of serine residues, threonine residues, and tyrosine residues can be 4% or more, 4.5% or more, 5% or more, 5.5% or more, 6% or more, 6.5% or more, or 7% or more, and can also be less than 35%, less than 33%, less than 30%, less than 25%, or less than 20%. The combined content of serine residues, threonine residues, and tyrosine residues can be 4% or more, and less than 35%, less than 33%, less than 30%, less than 25%, or less than 20%.

[0019] A polypeptide chain or protein may contain multiple amino acid sequences with high sequence identity (repetitive sequence units). The number of amino acid residues in a repetitive sequence unit can range from 6 to 200. The sequence identity between repetitive sequence units can be, for example, 85% or higher, 90% or higher, 95% or higher, 96% or higher, 97% or higher, 98% or higher, or 99% or higher. The hydrophilicity / hydrophobicity index of the repetitive sequence units can be, for example, -0.80 or higher, -0.70 or higher, -0.60 or higher, -0.50 or higher, -0.40 or higher, -0.30 or higher, -0.20 or higher, -0.10 or higher, 0.00 or higher, 0.22 or higher, 0.25 or higher, 0.30 or higher, 0.35 or higher, 0.40 or higher, 0.45 or higher, 0.50 or higher, 0.55 or higher, 0.60 or higher, 0.65 or higher, or 0.70 or higher. The hydrophilicity / hydrophobicity index of the repetitive sequence units can be below 1.0 or below 0.7. The hydrophilicity / hydrophobicity index of the repeating sequence unit can be above -0.80, above -0.70, above -0.60, above -0.50, above -0.40, above -0.30, above -0.20, above -0.10, above 0.00, above 0.22, above 0.25, above 0.30, above 0.35, above 0.40, above 0.45, above 0.50, above 0.55, above 0.60, above 0.65, or above 0.70, and below 1.0.

[0020] A polypeptide chain or protein may contain (A). n Motif, that (A) n The motif is an amino acid sequence primarily containing alanine residues. (A) n The motif can have an integer number of amino acid residues, ranging from 2 to 27, 2 to 20, 2 to 16, or 2 to 12. (A) n The proportion of alanine residues in the motif to the total number of amino acid residues can be 40% or more, 60% or more, 70% or more, 80% or more, 83% or more, 85% or more, 86% or more, 90% or more, 95% or more, or 100%.

[0021] The polypeptide chain or protein may contain glycine residues, serine residues, or alanine residues, and cysteine ​​residues arranged adjacent to these residues. Cysteine ​​residues may be arranged adjacent to glycine residues. Cysteine ​​residues with thiol groups in the block copolymers described later facilitate the formation of the first and second segments. Cysteine ​​residues may be located between glycine residues, serine residues, or alanine residues and glycine residues, serine residues, or alanine residues, or between serine residues and glycine residues.

[0022] In polypeptide chains or proteins, cysteine ​​residues can be positioned adjacent to hydrophobic amino acid residues. Cysteine ​​residues can be located between hydrophobic and non-hydrophobic amino acid residues. Cysteine ​​residues can be located between a hydrophobic amino acid residue and a glycine, serine, or alanine residue, or between a hydrophobic amino acid residue and a glycine residue. Hydrophobic amino acid residues can be selected from the group consisting of isoleucine, valine, leucine, phenylalanine, methionine, and alanine residues.

[0023] The molecular weight of a polypeptide chain or protein can be, for example, 200–1,000,000, 300–900,000, 400–800,000, 500–700,000, 600–600,000, 1,000–600,000, 3,000–600,000, 5,000–600,000, 10,000–600,000, or 5,000–100,000.

[0024] The molecular weight of a polypeptide chain or protein can be, for example, 1000 or more, 2000 or more, 3000 or more, 4000 or more, 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, 10000 or more, 20000 or more, 30000 or more, 40000 or more, 50000 or more, 60000 or more, 70000 or more, 80000 or more, 90000 or more, or 100000 or more, or it can be less than 400000, less than 360000, less than 300000, or less than 200000.

[0025] In this specification, the molecular weight of the polypeptide chain or protein refers to the value determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Electrophoresis is performed by the following steps: First, 200 μL of 2M lithium chloride DMSO (manufactured by Fujifilm and Koden Chemical) is added to 2 mg of powdered sample, and the mixture is heated at 80°C for 60 minutes, followed by heating at 95°C for 10 minutes while stirring to dissolve the sample. Then, the sample is diluted 50-fold with 10M urea solution, and then diluted 2-fold with sample buffer (manufactured by Fujifilm and Koden Chemical), and heated at 95°C for 5 minutes to denature the protein. Next, the SDS-PAGE gel (manufactured by Bio-lad) is mounted on the electrophoresis apparatus (manufactured by Bio-lad), and the apparatus is connected to the power supply (manufactured by Biocraft) while filling the apparatus with SDS buffer. The denatured sample was added in 10 μL to each well of the SDS-PAGE gel, and the current was applied at 30 mA / strip for 30 minutes. After electrophoresis, the SDS-PAGE gel was removed from the apparatus and immersed in Oriole fluorescent gel dye (manufactured by Bio-lad) and shaken for 1 hour. Then, the gel was placed on a UV sample tray (manufactured by Bio-lad), and staining images were obtained using a Gel Doc EZ gel imaging device (manufactured by Bio-lad).

[0026] The number of amino acid residues constituting a polypeptide chain or protein can be, for example, 50 or more, 100 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more, and can also be less than 5000, less than 4500, less than 4000, less than 3500, less than 3000, less than 2500, less than 2000, less than 1500, or less than 1000. The number of amino acid residues constituting a polypeptide chain or protein can be 50 or more, 100 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more, and less than 5000.

[0027] The proteins that make up the peptide polymers can be structural proteins, such as natural proteins selected from spider silk, silkworm silk, keratin, collagen, elastin, and sericin, as well as artificial proteins containing amino acid sequences derived from these proteins. In particular, the proteins can be artificial silk core proteins, or artificial spider silk core proteins.

[0028] Peptide polymers can be modified polypeptide chains having polypeptide chains and modifying groups bound to the polypeptide chains. The modifying groups on the modified polypeptide chains can be reactive functional groups. Reactive functional groups can be electrophilic, nucleophilic, or a combination of both. The modifying groups can, for example, bind to the polypeptide chain via ester bonds. Modifying groups that can be introduced into the polypeptide chain can be, for example, acyl groups. Peptide polymers with modified polypeptide chains help improve the durability (e.g., water resistance, weather resistance) of printed films.

[0029] The peptide polymer can be a block copolymer comprising a first segment and a second segment, wherein the first segment comprises a polypeptide chain and the second segment is bonded to the first segment. Printed films formed from printing inks containing this block copolymer as fixers readily possess high flexibility and extensibility. High flexibility and extensibility in the printed film help suppress cracking and peeling caused by deformation such as stretching and bending of the substrate. Examples of block copolymers described in this specification include substances identical to those described in International Publication WO2021 / 187502.

[0030] Block copolymers, as peptide polymers, may include a plurality of first segments and / or a plurality of second segments. The number of second segments contained in a block copolymer relative to a first segment may be 1 or more than 2, 2 or more but less than 10, 2 or more but less than 8, 2 or more but less than 6, or 2 or more but less than 4.

[0031] Block copolymers can be graft polymers, which have a first segment (main chain) and a second segment (side chain). The first and second segments can be alternately linked. Block copolymers can also have multiple first segments, forming a network structure by linking one second segment with two or more first segments.

[0032] The first and second segments can be linked by covalent bonds, ionic bonds, coordinate bonds, or combinations thereof, or they can be linked solely by covalent bonds. Covalent bonds can be formed between the linking group and the first segment, as described later.

[0033] The polypeptide chain contained in the first segment can be of the same type as the polypeptide chains and protein examples described above.

[0034] The second segment constituting a block copolymer (peptide polymer) can be a molecular group (molecule) with plasticizing function for polypeptide chains. A molecular group with plasticizing function for polypeptide chains refers to a molecular group containing only polypeptide chains that, compared to molded bodies such as fibers and films, has the function of improving the flexibility of such molded bodies. Printing films containing block copolymers with a second segment can have appropriate flexibility suitable for printed materials, wherein the second segment contains a molecular group with plasticizing function for polypeptide chains. Furthermore, block copolymers containing a second segment (containing a molecular group with plasticizing function for polypeptide chains) are particularly prone to good biodegradability.

[0035] The second segment constituting the block copolymer (peptide polymer) can be a molecular group containing at least one functional group selected from the group consisting of polyether, polyester, polycarbonate, polyamide, and polyol groups. Molecular chains containing these functional groups can have plasticizing functions on polypeptide chains.

[0036] Examples of polyether groups include functional groups derived from polyalkylene glycols such as polyethylene glycol, polypropylene glycol, ethylene oxide / propylene oxide copolymers, and polybutane glycol. Functional groups derived from polyalkylene glycols can be polymer chains formed by removing one or more hydrogen atoms from the polyalkylene glycol. When these polyether groups are included in the second segment, the polyether groups can be directly bound to heteroelements (O, N, S) in the ester, thioester, or amide groups containing the joints described later in the second segment, as needed. Alternatively, the polyether groups can be directly bound to heteroelements (O, N, S) in the ester, thioester, or amide groups of the polypeptide backbone contained in the first segment. In this case, the polyether groups as a whole are easily detached from the joints or the first segment. Therefore, the biodegradation rate of the polyether groups can be improved.

[0037] Examples of polyester groups include functional groups derived from polyesters such as polylactic acid, poly(3-hydroxybutyric acid), polyhydroxybutyric acid / hydroxyvalerate copolymer, polyhydroxybutyric acid / 4-hydroxybutyric acid copolymer, polyhydroxybutyric acid / hydroxyhexanoate copolymer, polypropylene terephthalate, butanediol / long-chain dicarboxylic acid copolymer, polyethylene terephthalate, polybutylene succinate, polybutylene succinate-adipate copolymer, polybutylene adipate-terephthalic acid copolymer, polycaprolactone, and poly(trimethylene furandicarboxylate); PTF. Functional groups derived from polyesters can be polymer chains formed by removing one or more hydrogen atoms from the polyester. Polyester groups can also be functional groups derived from those belonging to bioplastics or biodegradable plastics in the aforementioned polyesters, such as polycaprolactone.

[0038] Examples of polycarbonate groups include functional groups derived from polycarbonates such as 1,6-hexanediol polycarbonate, 1,5-pentanediol polycarbonate, and 1,10-decanediol polycarbonate, which have an aliphatic hydrocarbon chain as their backbone. Functional groups derived from polycarbonates can be polymer chains formed by removing one or more hydrogen atoms from polycarbonates.

[0039] Examples of polyamide groups include functional groups derived from polyamides such as nylon 3, nylon 4, nylon 5, nylon 6, nylon 11, and nylon 610. These polyamide functional groups can be polymer chains formed by removing one or more hydrogen atoms from the polyamide. The polyamide group can also be a functional group derived from the aforementioned polyamides that belong to bioplastics or biodegradable plastics.

[0040] As a polyol group (such as a polyvinyl alcohol group), examples include functional groups derived from polyvinyl alcohol, ethylene-vinyl alcohol copolymers, and other polyols (such as polyvinyl alcohol). The residues derived from polyols can be polymer chains formed by removing one or more hydrogen atoms from the polyol. The polyol group can be a functional group derived from the aforementioned polyols that belong to bioplastics or biodegradable plastics.

[0041] The second segment may also have a linking group between the aforementioned molecular group and the first segment. The linking group may be, for example, a divalent group represented by the following general formulas (1), (2a), (2b), (3a), (4a), (4b), (5), (6), (7), (8a), (8b), (9), (10), (11a), (11b), (13), (14), (15) or (16).

[0042] [Chemical Formula 1]

[0043] [Chemical Formula 2]

[0044] [Chemical Formula 3]

[0045] [Chemical Formula 4]

[0046] [Chemical Formula 5]

[0047] [Chemical Formula 6]

[0048] [Chemical Formula 7]

[0049] [Chemical Formula 8]

[0050] [Chemical Formula 9]

[0051] [Chemical Formula 10]

[0052] [Chemical Formula 11]

[0053] [Chemical Formula 12]

[0054] [Chemical Formula 13]

[0055] [Chemical Formula 14]

[0056] [Chemical Formula 15]

[0057] [Chemical Formula 16]

[0058] [Chemical Formula 17]

[0059] [Chemical Formula 18]

[0060] [Chemical Formula 19]

[0061] In general formulas (2a), (2b), (3a), (4a), (4b), (5), (6), (10), (11a), and (11b), Y independently represents an oxygen atom, a sulfur atom, or NR¹, and R¹ represents a hydrogen atom, a hydrocarbon group, an aromatic group, a carbonyl group, or a sulfonyl group. In general formulas (2a), (2b), (3a), (4a), (4b), (8a), (8b), (9), (10), (11a), and (11b), R independently represents a hydrogen atom, a hydrocarbon group, or an aromatic group.

[0062] The molecular weight of the second segment can be 200–500,000, 300–400,000, 350–350,000, 400–300,000, 500–200,000, 600–1,000,000, 700–50,000, 800–10,000, 900–7,500, or 1,000–5,000. The molecular weight can be the weight-average molecular weight measured by GPC.

[0063] When the molecular weight of the polypeptide chain in the first segment is set to 100, the molecular weight (or weight-average molecular weight) of the second segment can be, for example, 1–10000, 1.5–9000, 2–8000, 3–7000, 5–5000, 7–3000, or 10–2000. A higher molecular weight of the second segment relative to the first segment helps improve the flexibility of the printed film. A lower molecular weight of the second segment relative to the first segment helps improve the rigidity of the printed film.

[0064] In block copolymers, when the content of the second segment is set to 100, the mass ratio of the content of the first segment can be, for example, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 150 or more, 200 or more, 250 or more, 300 or more, 300 or more, 400 or more, 450 or more, 500 or more, 550 or more, or 600 or more, and can also be less than 1000, less than 900, less than 800, or less than 700. When the content of the second segment is set to 100, the mass ratio of the content of the first segment can be 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 150 or more, 200 or more, 250 or more, 300 or more, 300 or more, 400 or more, 450 or more, 500 or more, 550 or more, or 600 or more, and less than 1000.

[0065] The content of fixer or peptide polymer in printing ink, based on the total mass of the printing ink, can be 4% or more and 21% or less by mass. The content of fixer or peptide polymer in printing ink, based on the total mass of the printing ink, can be 7% or more, 9% or more, or 12% or more by mass, and can also be less than 19% by mass, less than 16% by mass, or less than 14% by mass.

[0066] The content of fixer or peptide polymer in printing inks, based on the total mass of components other than the liquid medium in the printing ink, can be 12% by mass or more and 99% by mass or less. The content of fixer or peptide polymer in printing inks, based on the total mass of components other than the liquid medium in the printing ink, can be 25% by mass or more, 37% by mass or more, or 50% by mass or more, and can also be less than 87% by mass, less than 74% by mass, or less than 62% by mass. The content of fixer or peptide polymer in the printed film formed from the printing ink can also fall within this range.

[0067] The liquid medium contained in printing inks can be selected from media capable of effectively dissolving or dispersing peptide polymers. Examples of liquid media include organic solvents capable of dissolving peptide polymers and / or colorants, such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), formic acid, ethanol, and hexafluoroisopropanol (HFIP). Liquid media can also be water, alkaline aqueous solutions, acidic aqueous solutions, or aqueous solutions containing inorganic salts, capable of dispersing peptide polymers and / or colorants.

[0068] The content of liquid medium in printing ink, based on the total mass of the printing ink, can be 37% or more and 73% or less. The content of liquid medium in printing ink, based on the total mass of the printing ink, can be 42% or more, 47% or more, or 52% or more, and can also be less than 68% or less, 63% or less, or 57% or less.

[0069] The colorants contained in printing inks can be dyes, pigments, or a combination of both.

[0070] The colorant content in printing ink, based on the total mass of the printing ink, can be 0.1% by mass or more and 50% by mass or less. The colorant content in printing ink, based on the total mass of the printing ink, can be 1% by mass or more, 4% by mass or more, 7% by mass or more, 14% by mass or more, or 21% by mass or more, and can also be less than 43% by mass, less than 36% by mass, or less than 29% by mass.

[0071] The colorant content in printing inks, based on the total mass of components other than the liquid medium in the printing ink, can be 0.7% by mass or more and 88% by mass or less. The colorant content in printing inks, based on the total mass of components other than the liquid medium in the printing ink, can be 3% by mass or more, 8% by mass or more, 13% by mass or more, 26% by mass or more, or 38% by mass or more, and can also be 75% by mass or less, 63% by mass or less, or 50% by mass or less. The colorant content in the printed film formed from the printing ink can also fall within this range.

[0072] Printing inks may contain additional components beyond fixers, liquid media, and colorants, depending on the requirements.

[0073] Examples of methods for manufacturing printed matter include: forming a film containing printing inks as shown in the examples above on a substrate by a printing process; removing a liquid medium from the formed film to form a printed film including a fixer and a colorant. The manufactured printed matter includes a substrate and a printed film disposed on the substrate. A certain amount of liquid medium may remain in the printed film.

[0074] The printing process that can be used is not particularly limited, and examples include conventional plate printing such as letterpress printing, gravure printing, offset printing, and screen printing (e.g., silkscreen printing); plateless printing such as inkjet printing; and dyeing. Examples of printing processes also include: placing a printing plate with a perforated support for the pattern or design to be printed on a substrate, and supplying printing ink thereon to form a printing film with the same pattern or design as the perforated portion of the printing plate. Liquid media can be removed, for example, by allowing the film containing printing ink to dry naturally. To remove liquid media, the film containing printing ink can be heated. After forming a printing film containing the printing inks disclosed herein on a substrate, one or more layers of printing films containing at least one of the printing inks disclosed herein and recognized printing inks can be formed on the printing film. Alternatively, after forming a printing film containing recognized printing inks on a substrate, one or more layers of printing films containing the printing inks disclosed herein can be formed on the printing film.

[0075] The substrate can be, for example, a fibrous aggregate, paper, leather, plastic parts, metal parts, ceramics, glass parts, wooden parts, food, or film. The fibrous aggregate can be, for example, textiles, fabrics, or non-woven fabrics. When the substrate is a fibrous aggregate composed of natural fibers, regenerated fibers, biodegradable synthetic fibers, artificial protein fibers, etc., paper, leather, biodegradable plastic parts, wooden parts, or food, the printed matter itself is likely to possess appropriate biodegradability. [Example]

[0076] The present invention is not limited to the following embodiments. 1. Formation of printing inks and printing films Example 1 The following substances were added to a sample vial with a stir bar: 5.2 g (0.52 mmol) of artificial protein (10 kDa), a peptide polymer mainly containing an amino acid sequence (A)n motif with an alanine residue, and an amino acid sequence having 5 amino acid residues with the (A)n motif; 0.8 g of pigment (HOLBEIN Paints Co., Ltd., carbon black, Holbein PG341) as a colorant; 0.3 g of sodium dodecyl sulfate; and 24 g of formic acid as a liquid medium. The mixture in the sample vial was stirred with a stir bar at room temperature for 30 minutes. Then, the mixture was degassed by centrifugation (manufactured by TOMY Co., Ltd., trade name: MX-307) to obtain the printing ink of Example 1 containing 17% by mass of artificial protein.

[0077] Using copy paper (manufactured by Alsoc Corporation, recycled copy paper R100, 80% whiteness) and cotton fabric (Soujitsugyo Co., Ltd., 182 cotton 40-count plain weave, 449 Cloud Cream color) as substrates, these were adhered to a stainless steel plate. On each substrate, 20g of printing ink was spread using a squeegee (0.4mm gap) to form an ink film. The substrates with the ink film were placed in a fume hood and left to stand at room temperature for 12 hours to allow the liquid medium (formic acid) in the ink film to evaporate. Through the evaporation of the liquid medium, a printed product with a printed film fixed to the substrate was formed.

[0078] Example 2 A block copolymer comprising a first segment and a second segment is prepared by means thereof, wherein the first segment (artificial protein) of the peptide polymer is a polypeptide chain, which mainly contains an amino acid sequence (A)n motif containing alanine residues and an amino acid sequence having 5 amino acid residues with the (A)n motif; the second segment comprises polyethylene glycol.

[0079] In a double-necked flask, 6 g (0.6 mmol) of the aforementioned artificial protein (10 kDa) as the peptide polymer and 85 mg (0.2 mmol) of dithiothreitol (DTT) as the reducing agent were added, followed by 63 g of dimethyl sulfoxide (DMSO). The mixture was heated and stirred at 85°C for 30 minutes to prepare a peptide solution. 6 g (0.6 mmol) of 10 kDa diterminated maleate polyethylene glycol was added to the peptide solution, and the mixture was heated and stirred at 85°C for 30 minutes to obtain a spinning solution containing a block copolymer.

[0080] To a 150 mL standard container specifically designed for a rotary mixer (Thinky Co., Ltd., ARE-310), 6 g of dimethyl sulfoxide (DMSO) as the liquid medium, 1 g of pigment (HOLBEIN Art Supplies Co., Ltd., carbon black, Holbein PG341) as the colorant, and 0.3 g of sodium dodecyl sulfate were added. The mixture in the standard container was treated for 5 minutes in mixing mode. 40 g of spinning solution containing block copolymer was added to the treated mixture, and the mixture was further treated for 5 minutes in mixing mode using the same rotary mixer. Subsequently, the mixture was treated for 5 minutes in degassing mode to obtain the printing ink of Example 2 containing 16% by mass of block copolymer (containing synthetic proteins and polyethylene glycol).

[0081] Using copy paper (manufactured by Alsoc Corporation, recycled copy paper R100, 80% whiteness) and cotton fabric (Soujitsugyo Co., Ltd., 182 cotton 40-count plain weave, 449 Cloud Cream color) as substrates, they were adhered to a stainless steel plate. The cotton fabric was then moistened with 10g of water. Subsequently, 20g of printing ink was spread on each substrate using a squeegee (0.4mm gap) to form a printing ink film. The substrates where the printing ink film was formed were heated at 60°C for 6 hours to evaporate the liquid medium (DMSO) in the printing ink film. Through the evaporation of the liquid medium, a printed product with a printing film fixed on the substrate was formed.

[0082] Comparative Example 1 Using copy paper (manufactured by Alsoc Corporation, recycled copy paper R100, 80% whiteness) and cotton fabric (Soujitsugyo Co., Ltd., 182 cotton 40-count plain weave, 449 Cloud Cream color) as substrates, these were adhered to a stainless steel plate. On each substrate, 5g of commercially available screen printing ink (water-based polyurethane rubber ink, Shin Nippon Sekisei Co., Ltd., RUBADA, black) was spread using a squeegee (0.4mm gap) to form a printing ink film. The substrates with the printed ink film were placed in a fume hood and left to stand at room temperature for 12 hours to allow the solvent (formic acid) in the printing ink film to evaporate. Through solvent evaporation, a printed product with a printing film fixed to the substrate was formed.

[0083] 2. The appearance of printed materials Figure 1 The images shown are photographs of printed materials obtained from the examples or comparative examples. The printing inks of Examples 1 and 2 are similar to commercially available printing inks, forming a fixed and uniform printed film on the substrate. This demonstrates that a printed film can be appropriately formed by forming a printing ink film layer in any area of ​​the substrate using various printing processes and then drying the film.

[0084] 3. Bending test Samples measuring 2cm × 5cm were cut from printed materials containing a substrate and a printing film obtained from the various embodiments and comparative examples. The samples were then wound around a polytetrafluoroethylene round rod (FLONChemical Co., Ltd.) with an outer diameter of 5mm and bent to observe the printing film. Figure 2 and Figure 3 A photograph of a printed item that has been bent. Figure 2 It is a printed product made from copy paper. Figure 3 The printed materials were made with cotton fabric as the base material. In all cases, no cracks or breaks were observed in the printing film due to bending.

[0085] 4. Ironing test Ironing test specimens measuring 4cm × 5cm were cut from printed cotton fabrics obtained in the various embodiments and comparative examples. A wiping paper (Elleair Soft Wiper S200, made of pulp) was placed on the surface of the printed film of the specimen, covering half of the printed film. The metal side of an iron (Twinbird Co., Ltd., model SA-4084BL) heated to a high set temperature was pressed over the wiping paper for 10 seconds. The wiping paper was then removed. Figure 4 A photograph of the printed material after the wiping paper has been removed. In Comparative Example 1, the printed film melted due to the heat of the iron, causing some wiping paper residue to remain and unable to be peeled off. In Examples 1 and 2, the wiping paper did not adhere to the printed film and could be completely removed. This confirms that the printed film formed from the printing ink containing peptide polymers has excellent heat resistance. For example, it is expected to enable ironing of fabrics decorated with the printed film.

Claims

1. A printing ink comprising: A fixing agent including a peptide polymer (having a polypeptide chain), a liquid medium, a colorant.

2. The printing ink according to claim 1, wherein, The polypeptide chain includes an artificial protein.

3. The printing ink according to claim 1, wherein, The peptide polymer further includes a modifying group bound to the polypeptide chain.

4. The printing ink according to claim 1, wherein, The peptide polymer is a block copolymer including a first segment containing the polypeptide chain, and a second segment having a plasticizing function with respect to the polypeptide chain.

5. The printing ink according to claim 1, wherein, The peptide polymer is a block copolymer including a first segment and a second segment, wherein the first segment contains the polypeptide chain, and the second segment includes at least one selected from the group consisting of a polyether group, a polyester group, a polycarbonate group, a polyamide group, and a polyol group.

6. The printing ink according to claim 1, wherein, At least one of the fixing agent or the colorant is dissolved in the liquid medium.

7. The printing ink according to claim 1, wherein, At least one of the fixing agent or the colorant is dispersed in the liquid medium.

8. A method of producing a printed matter, comprising: a step of forming a film including the printing ink according to any one of claims 1 to 7 on a substrate by a printing process; and a step of removing the liquid medium from the film, thereby forming a printed film containing the fixing agent and the colorant.

9. The method of claim 8, wherein, The substrate is a fiber aggregate, paper, a plastic member, a metal member, pottery, a glass member, a wooden member, or food.

10. A printed matter, including a substrate and a printed film provided on the substrate; wherein the printed film including a fixing agent including a peptide polymer (having a polypeptide chain), a colorant.

11. The printed article of claim 10, wherein, The substrate is a fiber aggregate, paper, a plastic member, a metal member, pottery, a glass member, a wooden member, or food.

Images