Writing instruments are composed of water-based inks

Abstract

A reducing particle dispersion is provided, which highly balances oxygen reduction performance (oxygen absorption capacity) and corrosion prevention performance. Moreover, while possessing its continuity (slow-release properties), it does not adversely affect other admixtures and exhibits excellent dispersion stability. The reducing particle dispersion disclosed herein can be exemplified by a polymer having at least one structural unit represented by the following general formula (I) as the main body, and for example, reducing particles containing at least one reducing component selected from group A below dispersed in water. [In the above formula (I), R is an alkyl group with 2 to 8 carbon atoms]. Group A: Polyphenols, copper chlorophyll, flavonoids, anthocyanins, butylated hydroxytoluene, butylated hydroxyanisole. In addition to reducing components, the aforementioned reducing particles are preferably also containing preservative components.

Description

Technical Field

[0001] This specification relates to a reducing particle dispersion that highly balances oxygen reduction performance (oxygen absorption capacity) and corrosion prevention performance. Moreover, while possessing its sustainability (slow-release properties), it does not adversely affect other admixtures and exhibits excellent dispersion stability. Prior Technology

[0002] In the past, various types of oxygen absorbers have been known for their applications in food, pharmaceuticals, drugs, cosmetics, electronic components, inks, and other fields. These include iron powder-based oxygen absorbers, catechin-based oxygen absorbers, ascorbic acid-based oxygen absorbers, and other types of oxygen absorbers.

[0003] For example, a powdered oxygen absorber is known, characterized by comprising a thermoplastic polymer (A) having a Munich viscosity of 10-400 and no crystallization melting peak or a melting point below 75°C when measured by differential scanning calorimeter (DSC), and having allyl hydrogen and / or hydrogen bonded to tertiary carbon in its molecule, and an oxidation promoting component (B), and having a specific surface area of ​​60 cm² / g or more (see, for example, Patent Document 1). Another known oxygen-absorbing particle comprises an organic oxide, a transition metal compound, an inorganic particle, and an organic polymer as oxygen-absorbing particles. The aforementioned inorganic particles are selected from inorganic porous particles and inorganic layered compound particles. At least a portion of the aforementioned organic oxide and at least a portion of the aforementioned transition metal compound are respectively present in the pores or between the layers of the aforementioned inorganic particles, and at least a portion of the aforementioned organic polymer is coated on at least a portion of the outer surface of the aforementioned inorganic particles (see, for example, Patent Document 2).

[0004] However, the powdered oxygen absorbers in the aforementioned patent documents 1 and 2 are mainly sealed in packaging bags for food, pharmaceuticals, drugs, cosmetics, electronic components, etc. Although they have oxygen reduction properties (oxygen absorption capacity), their sustainability is a challenge. Moreover, they are not intended for use in liquids such as household hygiene products, which may limit their use. Furthermore, they do not have any additional functions.

[0005] On the other hand, there is a known topical composition for anti-wrinkle, whitening, and anti-acne cosmetics, etc., which is selected from at least two of the following three groups: a group consisting of metal redox catalysts selected from substances or compounds containing these substances, or oxides thereof; a group consisting of redox enzymes selected from proteases, lipases, amylases, etc.; and a group consisting of reducing agents selected from ascorbic acid, coenzyme Q10, flavonoids, catechins, etc., wherein at least two components are selected from these groups, and the aforementioned metal redox catalysts and reducing agents or redox enzymes are crystallized and cross-linked metal redox catalysts. The medium and reducing agent or redox enzyme, or metal redox catalyst or redox enzyme conjugated to an insoluble polymer, or particles, preferably micron- or nano-sized particles (e.g., see Patent Document 3), are also known as nanocapsules coated with a polymer selected from the group consisting of proteins, polysaccharides, polyesters, polyacrylates, polycyanoacrylates, copolymers and / or mixtures thereof, and used for pharmaceutical, cosmetic and / or nutritional active ingredients, characterized by: a microemulsion containing water in a liquid lipid, and containing at least one hydrophilic active ingredient dissolved in an internal aqueous phase (e.g., see Patent Document 4).

[0006] However, the particles or nanocapsules described in the aforementioned patent documents 3 and 4 currently suffer from issues such as poor sustainability (slow-release) or dispersion stability in terms of reducing properties, or adverse effects on other blending components. In aqueous liquids containing reducing agents (antioxidants, etc.), problems such as instability of the components containing them, instability of the dispersion, physical colloidling, or separation also occur. Furthermore, reducing agents (antioxidants, etc.) rarely possess inherent preservative properties; in aqueous liquids, both reducing agents (antioxidants, etc.) and preservatives must be used together. [Previous Technical Documents] [Patent Literature]

[0007] [Patent Document 1] International Publication 2006 / 095640 (Scope of application, embodiments, etc.) [Patent Document 2] Japanese Patent Application Publication No. 2020-100801 (Scope of Application, Embodiments, etc.) [Patent Document 3] Japanese Patent Application Publication No. 2007-277212 (Scope of Application, Embodiments, etc.) [Patent Document 4] Japanese Patent Publication No. 2013-537206 (Scope of Application, Embodiments, etc.) Summary of the Invention

[0008] [The problem that the invention aims to solve]

[0009] In view of the problems and current status of the prior art mentioned above and intending to solve them, this disclosure presents a reducing particle dispersion that highly balances oxygen reduction performance (oxygen absorption capacity) and corrosion prevention performance. Moreover, while possessing its sustainability (slow-release properties), it does not adversely affect other admixtures and exhibits excellent dispersion stability.

[0010] That is, the reducing particle dispersion disclosed herein is characterized by: a polymer having at least one structural unit represented by the following general formula (I) in the repeating unit as the main body, and reducing particles containing reducing components dispersed in water. [In the above formula (I), R is an alkyl group with 2 to 8 carbon atoms]. Among the aforementioned reducing particles, the reducing component is preferably selected from at least one reducing component of group A below. Group A: Polyphenols, copper chlorophyll, flavonoids, anthocyanins, butylated hydroxytoluene, butylated hydroxyanisole The aforementioned reducing agent is preferably selected from at least one of chlorogenic acid, tannin, catechin, leucine, butylated hydroxytoluene, and butylated hydroxyanisole. The average particle size of the aforementioned particles is preferably 10~800nm. The aforementioned reducing particles are preferably those that contain preservative components in addition to reducing components. [Effects of the Invention]

[0011] According to this disclosure, a reducing particle dispersion can be provided, which highly balances oxygen reduction performance (oxygen absorption capacity) and corrosion prevention performance, and while having its continuity (slow release), it will not have an adverse effect on other admixtures, and has excellent dispersion stability. The purpose and effects of this disclosure can be identified and obtained by using the constituent elements and combinations specifically pointed out in the claims. The foregoing general description and the following detailed description are both illustrative and do not limit the scope of this disclosure as described in the claims. Implementation

[0012] The following describes in detail the embodiments disclosed herein. However, it should be noted that the technical scope of this disclosure is not limited to the embodiments described in detail below, and extends to the inventions described in the claims and their equivalents. The reducing particle dispersion disclosed herein is characterized by: a polymer having at least one structural unit represented by the following general formula (I) in the repeating unit as the main body, and reducing particles containing reducing components dispersed in water. [In formula (I) above, R is an alkyl group having 2 to 8 carbon atoms]

[0013] The reducing agent used in this disclosure is not particularly limited as long as it is a compound with the ability to reduce oxygen (oxygen absorption capacity). Various reducing agents can be used. In addition, if it is a commercially available product, its derivative (reducing agent) can be used. From the viewpoint of maximizing the effects of the invention, a suitable reducing agent is desirable that is selected from at least one (either alone or in mixtures of two or more, hereinafter the same) of group A below. Group A: Polyphenols, copper chlorophyll, flavonoids, anthocyanins, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA)

[0014] Usable polyphenols are compounds with phenolic molecules containing multiple hydroxyl groups. Examples of usable polyphenols, flavonoids, and anthocyanins include catechins (epicatechin, epigallocatechin, epigallocatechin gallate, epigallocatechin gallate, etc.), tannins, chlorogenic acid, caffeic acid, neochlorogenic acid, cyanidin, proanthocyanidins, thearubigins, rutin, flavonoids (quercetin, anthocyanins, flavanones, flavanols, flavonols, isoflavones, etc.), ferulic acid, gingerol, and anthocyanins (pelargonidin, cyanidin, delphinidin, etc.). Peony extract, mallow extract, petunia extract), flavonoids, chalcones (naringin, chalcone, etc.), lutein, sarsaparilla acid, sennain, hesperidin, magnolol, isomagnolol, ellagic acid, lignans, curcumin, coumarin, catechin, procyanidin, theaflavins, rosmarinic acid, xanthones, quercetin, resveratrol, gallic acid, propyl gallate, fluorotannins, paclitaxel [5-(dihydroxyphenylvinyl)resorcinol] (product name "Passienol PA"), resveratrol (3,5,4'-trihydroxy-trans-phosphoryl), etc.

[0015] From the perspective of reducing strength and safety, particularly suitable reducing agents include catechins, tannins, chlorogenic acid, lecithin, copper chlorophyll, ferulic acid, curcumin, shogaol, rutin, anthocyanins, isoflavones, anthocyanins (pelargonidin, cyanidin, delphinidin, peonidin, malvidin, petuniadin), butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). Chlorogenic acid, tannins, catechins, ferulic acid, lecithin, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) are preferred.

[0016] The reducible particle dispersion disclosed herein is based on a polymer having at least one structural unit represented by the general formula (I) above in a repeating unit, and reducible particles containing a reducing component are dispersed in water. Ideally, it is desirable to have a polymer having at least one structural unit represented by the general formula (I) above in a repeating unit as the main body, and reducible particles containing at least one reducing component selected from group A above are dispersed in water. The manufacturing method can be, for example, by using a polymer having a structural unit represented by the formula (I) above in a repeating unit as a shell and containing a reducing component. In the above general formula (I), the alkyl group of R having 2 to 8 carbons can be, for example, ethyl, propyl (straight chain, branched), butyl (straight chain, branched), pentyl (straight chain, branched), hexyl (straight chain, branched), heptyl (straight chain, branched), octyl (straight chain, branched), etc. Ideally, the alkyl group having 4 carbons and the octyl group having 8 carbons are preferred for use as an adhesive for wound suturing in the surgical field, especially isobutyl, n-octyl and 2-octyl. From the viewpoint of further maximizing the effects disclosed herein, it is particularly desirable that the polymer comprises at least one selected from isobutyl cyanoacrylate, n-butyl cyanoacrylate, tributyl cyanoacrylate, n-octyl cyanoacrylate, and 2-octyl cyanoacrylate. In addition, from a safety and stability point of view, the mass ratio of cyanoacrylate constituting the shell is preferably 90-100% by mass.

[0017] The particles disclosed herein contain the aforementioned reducing components, and the shell is composed of a polymer of cyanoacrylate having a structure represented by the aforementioned general formula (I) in repeating units. Within these particles, cyanoacrylate adheres to the bacterial cell wall, hindering cell wall synthesis, causing lysis, and preventing bacterial (including fungal) development, thus exhibiting antibacterial effects (antimicrobial and antifungal properties). Furthermore, the reducing components contained within these particles, as described above, also possess oxygen-reducing properties (oxygen absorption capacity). These properties are highly balanced without causing adverse effects on each other. In terms of corrosion resistance, it exhibits high safety, a broad antibacterial spectrum, excellent corrosion resistance (including antifungal effect), and excellent persistence (slow-release properties). In addition, it possesses persistence (slow-release properties) in oxygen-reducing properties (oxygen absorption capacity). While possessing these properties, it does not adversely affect other admixtures and forms a reducing particle dispersion with excellent dispersion stability in water (these points will be described in detail in the following examples).

[0018] The particle can be manufactured, for example, by adding the reducing component when polymerizing the structural unit (monomer) represented by the above general formula (I) by anionic polymerization, so that the reducing component is contained (encapsulated) inside the particle, and obtained in the form of an aqueous dispersion containing the particle. For the polymerization initiation and stabilization of the above polymerization, a polymerization agent may be used. Such a polymerization agent may include, for example, at least one sugar selected from the group consisting of polyoxyethylene sorbitan fatty acid esters, monosaccharides having hydroxyl groups, and disaccharides.

[0019] Examples of polyoxyethylene sorbitan fatty acid esters that can be used include, for example, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitic acid, polyoxyethylene sorbitan stearate, and polyoxyethylene sorbitan oleate. In addition to the aforementioned polyoxyethylene sorbitan fatty acid esters, the effect can be further enhanced by using sugars as polymerization agents. Any sugar that is a monosaccharide or disaccharide containing a hydroxyl group can be used; suitable examples include glucose, mannose, ribose, fructose, maltose, trehalose, lactose, and sucrose. These sugars can be in any form, either cyclic or chain-like. In the case of cyclic sugars, they can be either pyranose or furanose. Furthermore, various isomers exist within the sugar, and any of these isomers can be used. Monosaccharides typically exist in pyranose or furanose forms, while disaccharides are formed by α- or β-bonds of these monosaccharides; these sugars in their usual form can be used directly. Monosaccharides and disaccharides can be used alone or in combination.

[0020] The solvent for polymerization reactions is typically water (distilled water, purified water, pure water, etc.). Anionic polymerization can be initiated by hydroxide ions, therefore the pH of the reaction solution affects the polymerization rate. At a high pH, ​​the concentration of hydroxide ions is higher, resulting in faster polymerization; at a low pH, polymerization is slower. A suitable polymerization rate is usually obtained at an acidic pH of around 2-4. There are no particular restrictions on the acid added to make the reaction solution acidic; suitable acids that will not adversely affect the reaction include phosphoric acid, hydrochloric acid, acetic acid, phthalic acid, and citric acid.

[0021] The concentration of the structural unit represented by formula (I) in the polymerization reaction solution at the start of the reaction is not particularly limited, and is usually about 0.1 to 10% by mass, preferably about 1 to 5% by mass. Furthermore, the concentration of the polymerization reagent in the polymerization reaction solution at the start of the reaction (the total concentration in the case of multiple reagents) is not particularly limited, and is usually 1 to 30% by mass, preferably about 5 to 20% by mass. Additionally, the reaction temperature is not particularly limited, and it is simple and suitable to carry it at room temperature. The reaction time is not particularly limited, and is usually about 0.5 to 4 hours. The polymerization reaction is preferably carried out under stirring. Furthermore, neutral particles are usually used, so after the reaction, it is preferable to add an alkali such as an aqueous solution of sodium hydroxide to the reaction solution to neutralize it if necessary.

[0022] Through the above polymerization reaction, the structural unit represented by the above formula (I) undergoes anionic polymerization to produce polymer particles having the structure represented by formula (I) in the repeating unit, and the particle contains (includes) the above reducing component. The obtained particles, by including (encapsulating) the above-mentioned reducing components within polymer particles having the structure represented by the above general formula (I) in repeating units, can produce a reducing particle dispersion that is not currently available. In this dispersion, the individual antibacterial and antifungal effects of the particles and the reducing properties of the reducing components do not adversely affect each other. It highly balances the oxygen reducing properties (oxygen absorption capacity) and the anti-corrosion properties. Moreover, while possessing its sustainability (slow-release properties), it does not adversely affect other blending components, and exhibits excellent dispersion stability.

[0023] In this disclosure, the content of the reducing component (solid component) is preferably 1% by mass or more, preferably 5% by mass or more, more preferably 10 to 50% by mass, and especially preferably 15 to 40% by mass, relative to all polymer components, from the viewpoint of obtaining sufficient oxygen reduction performance (oxygen absorption capacity), obtaining a sustained reduction effect, and stability. By setting the content of the reducing component to 1% by mass or more, sufficient oxygen reduction performance (oxygen absorption capacity) and sustained reduction effect can be achieved. On the other hand, if the content of the reducing component is less than 1% by mass, the oxygen reduction performance (oxygen absorption capacity) is insufficient and the effect disclosed herein cannot be achieved.

[0024] Compared with using the aforementioned reducing components alone, this reducing particle dispersion (dispersion liquid) can produce a unique reducing particle dispersion that is not currently available. It possesses strong oxygen reducing properties (oxygen absorption capacity) and anti-corrosion properties, while also maintaining these properties. Furthermore, it has excellent dispersion stability and does not adversely affect other admixtures while maintaining its sustainability (slow-release properties).

[0025] In this disclosure, in order to further improve the anti-corrosion effect, the aforementioned reducing particles may contain preservative components in addition to the reducing components mentioned above. In the reducing particles disclosed herein, the shell is composed of a polymer of cyanoacrylate having a structure represented by the general formula (I) above in the repeating unit. The cyanoacrylate itself has antibacterial effect (antimicrobial and antifungal properties). From the viewpoint of further exerting a broad antibacterial spectrum and preservative effect (including antifungal effect), in addition to the above-mentioned reducing components, preservative components can also be contained to form reducing particles.

[0026] The preservative ingredients that may be used in this disclosure may be those that are well known in the past, preferably compounds that are highly safe and will not adversely affect the reducing components contained therein. In addition, any compound that has long-term antibacterial and antifungal properties is acceptable, and examples include at least one compound selected from group B below. Group B: Iodopropynyl compounds, sodium pentachlorophenate, 1,2-benzisothiazolin-3-one, 2,3,5,6-tetrachloro-4-(methylsulfonylurea)pyridine, p-hydroxybenzoate, phenol, sodium benzoate, sodium dehydrate acetate, potassium sorbate, morpholine, cresol, methylisothiazolinone, chloromethylisothiazolinone, octylisothiazolinone, dichlorooctylisothiazolinone, hexahydro-1,3,5-triazine (2-hydroxyethyl)-1,3,5-triazine, 2-bromo-2-nitroprop-1,3-diol, sodium 2-pyridinium thiosulfate, sodium pyrithione, 2-(4-thiazolyl)benzimidazole, 4-terpineol, 1,8-eucalyptus oil Alcohols, thymol, diisothiocyanate, eucalyptus oil, longifolene, isopropyl methylphenol, 2-methyl-4-isothiazolin-3-one, citral, eugenol, allyl isothiocyanate, d-carmine, tannic acid, ethylparaben, benzalkonium chloride, glyceryl caprylate, glyceryl fatty acid ester, chlorophenoxyethanol, salicylic acid, ethylparaben, butylparaben, propylparaben, methylparaben, bisabolol, juniperol, phenethyl alcohol, phenoxyethanol, butylparaben, propylparaben, benzalkonium chloride, methylparaben, 2-(4-thiazolyl)benzimidazole

[0027] Among the preservative components in Group B mentioned above, from the viewpoints of time-to-time stability, ease of availability, low cost, and safety, the more suitable ones are iodopropynyl compounds, 1,2-benzisothiazolin-3-one, 2,3,5,6-tetrachloro-4-(methylsulfonylurea)pyridine, sodium benzoate, sodium dehydrate acetate, potassium sorbate, cresol, methylisothiazolinone, chloromethylisothiazolinone, octylisothiazolinone, dichlorooctylisothiazolinone, hexahydro-1,3,5-triazine (2-hydroxyethyl)-1,3,5-triazine, 2-bromo-2-nitroprop-1,3-diol, sodium 2-pyridinium thiosulfate, and sodium pyrithione. 2-(4-Thiazolyl)benzimidazole, 4-terpineol, 1,8-Cephalosporinol, diisothiocyanate, isopropyl methylphenol, 2-methyl-4-isothiazolin-3-one, citral, eugenol, allyl isothiocyanate, D-carboxene, tannic acid, ethylparaben, benzalkonium chloride, glycerol fatty acid ester, salicylic acid, ethylparaben, butylparaben, propylparaben, methylparaben, juniper alcohol, phenethyl alcohol, phenoxyethanol, butylparaben, propylparaben, benzalkonium chloride, methylparaben, 2-(4-Thiazolyl)benzimidazole.

[0028] In addition to the aforementioned reducing components, the reducing particles also contain preservative components. The manufacturing of reducing particles containing the aforementioned reducing components can be carried out by using a polymer having a structural unit represented by the aforementioned formula (I) in a repeating unit as a shell, and containing the aforementioned reducing components and preservative components. The structural unit represented by the aforementioned formula (I) undergoes anionic polymerization to produce polymer particles having a structure represented by formula (I) in a repeating unit, and the aforementioned reducing components and preservative components are contained (encapsulated) inside the particles. The obtained particles, by including (encapsulating) the reducing component and the preservative component within polymer particles having the structure represented by the general formula (I) above in repeating units, can yield a reducing particle dispersion that is not currently available. In this dispersion, the individual antibacterial and antifungal effects of the particles, the preservative effect of the preservative component, and the reducing properties of the reducing component do not adversely affect each other. It highly balances the oxygen reduction performance (oxygen absorption capacity) with the antibacterial effect (antibacterial and antifungal properties) generated by the cyanoacrylate itself and the preservative properties of the preservative component (hereinafter referred to as "composite preservative properties"). Moreover, while possessing its sustainability (slow-release properties), it does not adversely affect other blended components, and exhibits excellent dispersion stability.

[0029] In this disclosure, the content of the above-mentioned preservative components (solid components) is preferably 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1 to 40% by mass, and especially preferably 3 to 30% by mass, relative to all polymer components, from the viewpoint of obtaining composite anti-corrosion performance, obtaining sustained anti-corrosion effect, and stability. By setting the content of the preservative component to 0.1% by mass or more, sufficient composite anti-corrosion performance and continuous anti-corrosion effect can be achieved. On the other hand, if the content of the preservative component is less than 0.1% by mass, the effect of containing the preservative component is lacking.

[0030] Furthermore, in this disclosure, the average particle size of the obtained reducing particles (containing reducing components, or containing reducing components + preservative components, the same below) will vary depending on the monomer having the above general formula (I), its content, polymerization conditions, etc., preferably 10~800 nm, more preferably 20~400 nm, and ideally 30~200 nm. By setting the average particle size within the aforementioned suitable range, it is suitable for various applications and maintains excellent stability. Furthermore, the "average particle size" specified in this disclosure is the histogram average particle size obtained from the intensity distribution of scattered light. In this disclosure (including the embodiments described later), it is the D50 value measured by a particle size distribution measuring device [FPAR1000 (manufactured by Otsuka Electronics Co., Ltd.)].

[0031] The reducing particle dispersion disclosed herein contains particles with the aforementioned characteristics that highly balance oxygen reduction performance (oxygen absorption capacity) and anti-corrosion performance (including composite anti-corrosion performance). Moreover, while possessing its sustainability (slow-release properties), it does not adversely affect other admixtures, and exhibits excellent dispersion stability. The aforementioned anti-corrosion effects (including anti-mildew effects) can exert antibacterial effects (including anti-mildew effects) on many bacteria or fungi, including Gram-negative and Gram-positive bacteria. The sustained effects of its anti-corrosion performance (including composite anti-corrosion performance) and reducing properties also last for a long time.

[0032] The reducing particle dispersion disclosed herein, constructed in this manner, can be used to impart anti-corrosion and reducing properties to various products, such as ink compositions for medical devices, baby products, care products, bath products, kitchenware, tableware, drinking water piping parts, hygiene products, household appliances, clothing, building materials, agricultural materials, automotive interior parts, stationery, writing instruments, or inkjet printers. In addition to the uses mentioned above, it is also suitable for applications such as detergents, fabric softeners, household detergents, dishwashing liquids, and hard surface detergents; personal care applications such as shampoos, conditioners, lotions, creams, sunscreens, foundations, eye makeup products, antiperspirants, and toothpaste powder; industrial water treatment applications such as coatings, adhesives, building materials, resin latexes, wood preservatives, cement mixes, boilers, cooling equipment, drainage treatment equipment, and industrial water (water used in the papermaking process, cooling water, or washing water for various industries); electronic applications such as medical devices, food additives, solar cell modules or organic component devices, and heat shielding films; and applications in water tanks and medicated baths to inhibit water mold growth in aquatic organisms (such as fish).

[0033] Furthermore, the following details the application of the reducible particle dispersion disclosed herein to writing instruments such as ballpoint pens, markers, and fountain pens in water-based ink compositions. The writing instrument disclosed herein is composed of water-based ink, characterized in that it contains at least the reducing particle dispersion described above, and may also contain coloring agents and water-soluble organic solvents in addition to the reducing particle dispersion. From the viewpoint that the content of reducing particles in the ink composition does not impair writing performance, achieves the effects disclosed herein, and maintains stability, the content is preferably 0.1 to 30.0% by mass relative to the total amount of ink composition, in terms of solid content, and more ideally, it is 1.0 to 15.0% by mass.

[0034] The coloring agents that can be used include water-soluble dyes and pigments, such as inorganic pigments, organic pigments, plastic pigments, hollow resin particles with internal pores as white pigments, or resin particles dyed with dyes with excellent color development and dispersibility (pseudo-pigments), etc. Water-soluble dyes may be used in appropriate amounts of any of the direct dyes, acid dyes, food dyes, and basic dyes without impairing the effects of this disclosure. The content of these colorants varies depending on the type of writing instrument, and ranges from 1 to 30% by mass relative to the total amount of ink components.

[0035] Examples of water-soluble organic solvents that can be used include ethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2,5-hexanediol, 3-methyl-1,3-butanediol, 2-methylpentane-2,4-diol, and 3-methylpentanediol. At least one of the following: -1,3,5-triol, 1,2,3-hexanediol, etc.; polyalkylene diols such as polyethylene glycol and polypropylene glycol; glycerols such as glycerol, diglycerol, and triglycerol; lower alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc.; N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, etc.

[0036] Other water-soluble solvents that can be mixed include, for example, alcohols such as methanol, ethanol, isopropanol, n-butanol, tributanol, isobutanol, hexanol, octanol, nonanol, decanol, benzyl alcohol, etc.; acetamides such as dimethylformamide and diethylacetamide; and ketones such as acetone. The content of these water-soluble organic solvents varies depending on the type of writing instrument, such as a ballpoint pen, marker, or fountain pen. It ranges from 1% to 40% by mass relative to the total ink composition. From the perspective of further improving the drying properties of lines, it is particularly effective for ink compositions with a mass of less than 10% by mass. Ideally, it should be set at 3% to 8% by mass.

[0037] In the water-based ink composition of the writing instruments disclosed herein, the remaining portion other than the particles, colorants, and water-soluble solvents with the aforementioned characteristics, excluding the water used as a solvent (tap water, purified water, distilled water, ion-exchanged water, pure water, etc.), may appropriately contain dispersants, lubricants, pH adjusters, rust inhibitors, thickeners, evaporation inhibitors, surfactants, fixatives, etc., to a extent that does not impair the effects of this disclosure.

[0038] The dispersants that can be used include nonionic, anionic surfactants, or water-soluble resins. Water-soluble polymers are suitable. Lubricants, including nonionic polyol fatty acid esters, high carbon fatty acid esters of sugars, polyoxyalkylene high carbon fatty acid esters, alkyl phosphate esters, etc., which can also be used as surface treatment agents for pigments, or anionic alkyl sulfonates of high carbon fatty acid amides, alkyl allyl sulfonates, etc., derivatives of polyalkylene glycols or fluorinated surfactants, polyether modified polysiloxanes, etc.

[0039] pH adjusters can include ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, or alkali metal salts of carbonic or phosphoric acid such as sodium tripolyphosphate and sodium carbonate, as well as alkali metal hydrates such as sodium hydroxide. Rust inhibitors can include benzotriazole, toluenetriazole, dicyclohexylammonium nitrite, and saponins. Thickening agents include carboxymethyl cellulose (CMC) or its salts, cellulose derivatives such as fermented cellulose and crystalline cellulose, and polysaccharides. Usable polysaccharides include xanthan gum, guar gum, hydroxypropylated guar gum, casein, gum arabic, gelatin, amylose, agarose, sulfur agar, arabinogalactan, cardan gum, callose, carboxymethyl starch, chitin, chitosan, quince seed, glucomannan, galvanic gum, tamarind gum, polydextrose, Aspergillus niger polysaccharide, hyaluronic acid, rock tripe polysaccharide, seaweed gum, HM pectin, laver polysaccharide, lichen polysaccharide, carrageenan, alginic acid, tragacanth gum, gum arabic, succinyl acnean, locust bean gum, and tara gum. These can be used individually or in combination of two or more. Furthermore, commercially available products of these types can also be used.

[0040] Evaporation inhibitors include, for example, pentaerythritol, p-xylene glycol, trimethylolpropane, triethylolpropane, and dextrin. Surfactants can be categorized into, for example, fluorinated, polysiloxane, and acetylene glycol-based surfactants. The fixing agent may include water-soluble resins with an intramolecular hydrophobic portion, such as polyacrylic acid, water-soluble styrene-acrylic resin, water-soluble styrene-maleic acid resin, polyvinyl alcohol, polyvinylpyrrolidone, water-soluble maleic acid resin, water-soluble styrene resin, polyvinylpyrrolidone, polyvinyl alcohol, water-soluble ester-acrylic resin, ethylene-maleic acid copolymer, polyethylene oxide, and water-soluble urethane resin; and at least one resin latex selected from polyolefin latex, acrylic latex, vinyl acetate latex, urethane latex, styrene-butadiene latex, and styrene-acrylonitrile latex. It is desirable to use one or more of these, and a total of two or more.

[0041] The water-based ink composition for writing instruments disclosed herein can be prepared by appropriately combining the particles with the aforementioned characteristics, water-soluble solvents, and other components according to the intended use of ink for writing instruments (ballpoint pens, marker pens, etc.), mixing them using a homogenizer, homogenizer, or disperser, and further removing coarse particles from the ink composition by filtration or centrifugation as necessary.

[0042] Furthermore, from the perspectives of usability, safety, stability of the ink itself, and compatibility with the ink container, the pH of the water-based ink composition of the writing instruments disclosed herein should ideally be adjusted to 5-10, with an even more ideal value of 6-9.5.

[0043] The writing instrument disclosed herein is composed of water-based ink and can be mounted on the tip of a ballpoint pen, marker, or similar pen, which has a ballpoint pen tip, a fiber pen tip, a felt pen tip, or a plastic pen tip. Ballpoint pens include writing instruments with the above-mentioned composition that contain water-based ink components within a ballpoint pen ink reservoir (replacement refill) with a diameter of 0.18 to 2.0 mm, and that contain a substance that is incompatible with the water-based ink components contained within the ink reservoir and has a smaller specific gravity than the water-based ink components, such as polybutene, polysiloxane, mineral oil, etc., as an ink follower. Furthermore, the construction of ballpoint pens and markers is not particularly limited, and can be, for example, a direct-liquid ballpoint pen or marker with the pen refill tube itself as the ink reservoir, and the pen refill tube filled with a water-based ink composition of the writing instrument described above.

[0044] In the water-based ink composition for writing instruments disclosed herein, which is constructed in this manner, the reducing particle dispersion with the aforementioned properties is incorporated into the water-based ink composition for writing instruments. Therefore, it can highly balance the oxygen reduction performance (oxygen absorption capacity) and anti-corrosion performance (including composite anti-corrosion performance) in the ink composition. Moreover, while possessing its persistence (slow-release properties), it does not adversely affect other ink blending components. Furthermore, even in the ink formulation system, it exhibits excellent dispersion stability, thus suppressing the formation of bubbles and maintaining its continuous effect for a long time. Moreover, these particles do not impair storage stability or writing performance, thereby further increasing the freedom of ink design and obtaining water-based ink compositions for writing instruments such as ballpoint pens and markers. [Example]

[0045] The present disclosure will now be described in further detail with reference to embodiments and comparative examples; however, the present disclosure is not limited to the embodiments described below. [Examples 1-9: Preparation of reducing particle dispersions A-I] Reducible particle dispersions A to I were manufactured according to Examples 1 to 9 below. Furthermore, "parts" below refers to parts by mass.

[0046] (Example 1: Preparation of reducing particle dispersion A) A stirrer, reflux condenser, and thermometer were installed in a 2-liter flask placed in a water bath. 93.8 parts distilled water, 2 parts monolauric polyoxyethylene sorbitan anhydride (20E.O), 0.2 parts phosphoric acid, 4 parts of isobutyl monomer (isobutyl cyanoacrylate) where R in formula (I) is an isobutyl group, and 2 parts chlorogenic acid as a reducing agent were added. The mixture was stirred for approximately 15 minutes to complete the anionic polymerization, yielding antibacterial particle dispersion A. Furthermore, the average particle size was 85 nm.

[0047] (Examples 2-6: Manufacturing of particles B-F) Following the formulations shown in Table 1 below, and similarly to Example 1 above, each reducing particle dispersion B to F was obtained. Furthermore, the average particle size of each particle is shown in Table 1 below. (Examples 7-9: Manufacturing of particles G-I) Following the formulation composition shown in Table 1 below, and similarly to Example 1 above, reducing agents and preservatives were used to obtain each reducing particle dispersion G~I. Furthermore, the average particle size of each particle is shown in Table 1 below.

[0048] The reducing particle dispersions (dispersions) obtained in Examples 1 to 9 above were obtained. The solid content of the reducing particles in the reducing particle dispersions obtained in Examples 1 to 9 was 35 to 40% by mass. Using the reducing particle dispersions (dispersions) obtained in Examples 1 to 9 above, the sustainability of reducing performance (ability to remove dissolved oxygen), dispersion stability, and anti-corrosion performance were evaluated by the following evaluation method. Reference Example 1 uses a reducing dispersion (dispersion: chlorogenic acid solution). These results are presented in Table 1 below.

[0049] (Methods for evaluating restoration performance) Using the reducing particle dispersions (dispersions) obtained in Examples 1-9 and Reference Example 1 above, the reducing properties were evaluated by measuring dissolved oxygen content. The evaluation was conducted using a dissolved oxygen meter: WQ-320 (manufactured by Horiba Manufacturing Co., Ltd.). After the reducing particle dispersions were prepared, they were placed at a temperature of 25°C for 48 hours and 3 months. The persistence of the reducing performance measured at a temperature of 25°C was evaluated according to the following evaluation criteria. Evaluation benchmarks: A: The dissolved oxygen content is less than 0.1~10 mg / L. B: Dissolved oxygen content is less than 10~20 mg / L. C: Dissolved oxygen content is above 20 mg / L.

[0050] (Methods for assessing distributed stability) Ten ml of each of the reducing particle aqueous dispersions obtained using the reducing dispersions (dispersions) of Examples 1-9 and Reference Example 1 were filled into a 15 ml glass capped bottle along with a stirring ball (φ6.4 mm, stainless steel). After sealing, the bottle was stored at 40°C for one month with the cap facing upwards. Then, each dispersion was shaken. The dispersion stability was evaluated according to the following evaluation criteria by the number of times the stirring ball began to move within the glass capped bottle. Evaluation benchmarks: A: 0~3 times. B: 4~10 times. C: 11 times or more. ※0 times: The movement of the stirring ball can be observed when the glass bottle with the cap is tilted.

[0051] (Test methods for preservative effects (antibacterial and antifungal properties)) Using the reducing dispersions (dispersions) of Examples 1-9 and Reference Example 1 obtained above, the following microbiological testing methods, based on ISO 11930:2012 (preservation efficacy testing or microbiological risk assessment, or methods for interpreting data generated from both), were performed. The challenge test was conducted using the following three groups: bacteria, yeast, and filamentous fungi. Bacterial flora: Stapylococcus aureus NBRC13276, Escherichia coli NBRC3972 Yeast: Candida albicans NBRC1594 Filamentous fungus: Aspergillus brasiliensis <Preparation of Inoculation Solution> Preparation of inoculum: Prepare the inoculum according to ISO 11930:2012. Bacterial flora: Bacterial solutions of each bacterial species were prepared according to ISO 11930:2012. The three bacterial solutions, each adjusted to 1×10⁷~1×10⁸ cfu / ml, were mixed in equal volumes to serve as the inoculum. Yeast: Prepare bacterial culture according to ISO 11930:2012, at a concentration of 1×10⁶ to 1×10⁷ cfu / ml. Filamentous bacteria: Prepare bacterial suspensions according to ISO 11930:2012, at a concentration of 1×10⁶ to 1×10⁷ cfu / ml. <Vaccination> For inoculation of the dispersion, use 1% by mass of bacterial suspension. <save> The inoculated writing instrument ink composition was stored at a temperature of 22.5±2.5℃ and monitored at specified intervals. <Detection and Cultivation> Bacterial culture was cultured on SCD agar medium, yeast on SD agar medium, and filamentous bacteria on PD agar medium. Ten samples were spread with a total of 1g of each culture. Bacterial culture and yeast were cultured at 32.5℃ for 2 days, and filamentous bacteria were cultured at 22.5℃ for 5 days. <Evaluation Criteria> A+: No colonies were observed on day 3. A: No colonies were observed on day 7. B: No colonies were observed on day 21. C: Several to dozens of colonies appear at the 28th day. D: There was a significant increase at the 28-day mark.

[0052]

[0053] The results in Table 1 clearly show that the reducing particle dispersions (dispersion liquids) obtained in Examples 1 to 9 have a high balance between oxygen reduction performance (oxygen absorption capacity) and corrosion prevention performance. Moreover, while having its continuity (slow-release properties), it does not have an adverse effect on other admixtures, and has excellent dispersion stability. In addition, the reducing particle dispersions (dispersion liquids) of Examples 7-9 contain preservative components in addition to reducing components in order to further improve the anti-corrosion effect. It was confirmed that compared with the reducing particle dispersions (dispersion liquids) containing the reducing components of Examples 1-6, the anti-corrosion performance was further improved, and the sustained effect did not have an adverse effect on other blended components, and the dispersion stability was excellent.

[0054] [Examples 10-18 and Comparative Examples 1-3: Preparation of Water-Based Ink Composition for Writing Instruments] The reducing particle dispersions (dispersions) obtained in Examples 1-9 were used in Examples 10-18. The solid content of the reducing particles in the reducing particle dispersions obtained in Examples 1-9 was 35-40% by mass. On the other hand, Comparative Examples 1 to 3 used the following three known oxygen absorbers. Comparative Example 1 used sodium L-ascorbate, Comparative Example 2 used N-acetylglucosamine, and Comparative Example 3 used an oligomer of N-vinyl-2-pyrrolidone (degree of polymerization: 2~6).

[0055] Using the reducing particle dispersions (particles A to I) produced in Examples 1 to 9 above, and Comparative Examples 1 to 3 above, water-based ink compositions for writing instruments were prepared by conventional methods according to the formulations (total mass 100%) shown below. Ink composition: (total 100% by mass) 15.0% by mass of each reducing particle dispersion (particles A-F) or comparative examples 1-3 Colorant (Carbon Black MA100, manufactured by Mitsubishi Chemical Corporation) 5.4% by mass pH adjuster (triethanolamine) 1.4% by mass Water-soluble organic solvent (propylene glycol) 15.0% by mass Tackifier (xanthan gum) 0.2% by mass 63.0% by mass of ion-exchanged water

[0056] For each writing instrument containing water-based ink (total mass 100%), the following evaluation methods were used to evaluate the writeability (difference in line density between upper and lower lines), the bubble formation after a certain period of time, and the bubble formation after impact for writing instruments A and B with the following composition. The evaluation results of Examples 10-18 and Comparative Examples 1-3 are disclosed in Table 2 below.

[0057] (Writing tools: Making a ballpoint pen) The pen refill of the cap-type ballpoint pen A [manufactured by Mitsubishi Pencil Corporation, trade name: Signo UM-100] is filled with the above-mentioned water-based ink components in a replacement refill formed by a polypropylene ink reservoir tube with an inner diameter of 4.0 mm and a length of 113 mm, a stainless steel pen tip (super-hard alloy steel ball, steel ball diameter 0.5 mm), and a connector connecting the reservoir tube and the pen tip. An ink follower with mineral oil as the main component is then filled at the rear end of the ink reservoir to produce a water-based ballpoint pen. The automatic ballpoint pen B [manufactured by Mitsubishi Pencil Corporation, trade name: Signo UMN152] is manufactured by filling the aforementioned water-based ink components into a replacement refill formed by a polypropylene ink reservoir tube with an inner diameter of 4.0 mm and a length of 113 mm, a stainless steel nib (with a super-hard alloy steel ball, 0.5 mm in diameter), and a connector connecting the reservoir tube and the nib. An ink follower with a mineral oil-based component is then inserted at the rear end of the ink reservoir.

[0058] [Assessment methods for handwriting quality (difference in underline density)] After placing each of the above-described water-based ballpoint pens A at room temperature (25°C, the same applies below) for one month, write until the ink runs out, compare the difference in line density between the beginning and end of writing, and evaluate according to the following evaluation criteria. Evaluation benchmarks: A: There is no difference in concentration. B: Slight concentration differences were observed. C: A clear difference in concentration was observed. D: Significant concentration differences were observed, making it difficult to identify by drawing lines.

[0059] <Methods for assessing bubble formation after a certain period of time> Each ballpoint pen A constructed as described above was stored with its tip facing down in a gas environment of 50°C and 30%RH for one month. After the aforementioned period, the pen was placed at room temperature with its tip facing down for 6 hours to visually confirm the presence of air bubbles at the interface between the ink and the ink carrier. The pen was then evaluated according to the following evaluation criteria.

[0060] <Methods for assessing the formation of bubbles after impact> The above-described automatic ballpoint pen B, with the nib facing down, is tapped 5 times. Then, with the nib facing down, it is stored in the above-described gas environment of 50°C and 30%RH for 1 week. After the above period, the nib is kept facing down and placed at room temperature for 6 hours to visually confirm the air bubbles appearing at the interface between the ink and the ink follower. The evaluation is then carried out according to the following evaluation criteria. Evaluation benchmarks: A: There are absolutely no air bubbles at the ink-ink follower interface. B: There is an air bubble with a diameter of less than 1 mm at the interface between the ink and the ink follower. C: There is one or more air bubbles with a diameter of 1 mm or more at the interface between the ink and the ink follower, or there are two or more air bubbles with a diameter of less than 1 mm. D: The ink follower is pushed up by the air bubble, and there are gaps between the ink interfaces.

[0061] <Evaluation Methods for Corrosion Resistance> For each writing instrument containing water-based ink (total mass 100%), microbiological testing was performed according to the following method based on ISO 11930:2012 (testing of preservation efficacy or microbiological risk assessment, or methods for interpreting data arising from both). The challenge test was conducted using the following three groups: bacteria, yeast, and filamentous fungi. Bacterial flora: Stapylococcus aureus NBRC13276, Escherichia coli NBRC3972 Yeast: Candida albicans NBRC1594 Filamentous fungus: Aspergillus brasiliensis <Preparation of Inoculation Solution> Preparation of inoculum: Prepare the inoculum according to ISO 11930:2012. Bacterial flora: Bacterial solutions of each bacterial species were prepared according to ISO 11930:2012. The three bacterial solutions, each adjusted to 1×10⁷~1×10⁸ cfu / ml, were mixed in equal volumes to serve as the inoculum. Yeast: Prepare bacterial culture according to ISO 11930:2012, at a concentration of 1×10⁶ to 1×10⁷ cfu / ml. Filamentous bacteria: Prepare bacterial suspensions according to ISO 11930:2012, at a concentration of 1×10⁶ to 1×10⁷ cfu / ml. <Vaccination> For writing instruments, inoculate the ink composition with a bacterial solution of 1% by weight. <save> The inoculated writing instrument ink composition was stored at a temperature of 22.5±2.5℃ and monitored at specified intervals. <Detection and Cultivation> Bacterial culture was cultured on SCD agar medium, yeast on SD agar medium, and filamentous bacteria on PD agar medium. Ten samples were spread with a total of 1g of each culture. Bacterial culture and yeast were cultured at 32.5℃ for 2 days, and filamentous bacteria were cultured at 22.5℃ for 5 days. <Evaluation Criteria> A+: No colonies were observed on day 3. A: No colonies were observed on day 7. B: No colonies were observed on day 21. C: Several to dozens of colonies appear at day 28. D: There was a significant increase at the 28-day mark.

[0062]

[0063] If we examine Table 2 above, it can be confirmed that Examples 10 to 18 within the scope of this disclosure, compared with Comparative Examples 1 to 3 outside the scope of this disclosure, have writeability (difference in the density of the upper and lower lines), no bubbles are generated after a certain period of time, and no bubbles are generated after being impacted. While having strength and continuity in oxygen reduction performance (oxygen absorption capacity), they do not adversely affect the blending components of other inks. Furthermore, it was confirmed that all the ballpoint pens A and B produced above did not experience ink leakage or bleed, and had sufficient line density to produce clear lines. Furthermore, it was confirmed that the water-based ink composition for writing instruments using the reducing particle dispersions (dispersion liquids) of Examples 16-18 further contains preservative components in addition to the reducing components to improve the anti-corrosion effect. Compared with the reducing particle dispersions (dispersion liquids) containing the reducing components of Examples 10-15, the anti-corrosion performance is further improved, and its sustained effect does not adversely affect other admixtures, etc., and the dispersion stability is excellent. [Industry availability]

[0064] The reducing particle dispersion disclosed herein possesses both strong and sustained oxygen-reducing properties (oxygen absorption capacity) (slow-release properties) without adversely affecting other admixtures. Furthermore, it exhibits excellent dispersion stability and corrosion resistance. Therefore, it can be used to impart reducing and corrosion-resistant properties to various products, such as ink compositions for medical devices, baby products, care products, bath products, kitchenware, tableware, drinking water piping parts, hygiene products, household appliances, clothing, building materials, agricultural materials, automotive interior parts, stationery, writing instruments, or inkjet printers.

Claims

1. A water-based ink composition for writing instruments, characterized by containing a reducing particle dispersion, a colorant, a pH adjuster, a water-soluble organic solvent, a thickener, and deionized water, wherein the aforementioned reducing particle dispersion is mainly composed of a polymer having at least one structural unit represented by the following general formula (I) in its repeating unit, and the reducing particles containing the reducing component are dispersed in water, [in the above formula (I), R is an alkyl group having 2 to 8 carbon atoms].

2. The writing instrument of claim 1 is composed of water-based ink, wherein the reducing particles contain at least one reducing component selected from Group A: polyphenols, copper chlorophyll, flavonoids, anthocyanins, butylated hydroxytoluene, and butylated hydroxyanisole.

3. The writing instrument of claim 1 or 2 is composed of water-based ink, wherein the average particle size of the aforementioned particles is 10 to 800 nm.

4. The writing instrument of claim 1 is composed of water-based ink, wherein the aforementioned reducing component is selected from at least one of chlorogenic acid, tannin, catechin, leucine, butylated hydroxytoluene, and butylated hydroxyanisole.

5. The writing instruments of claim 1 or 2 are composed of water-based ink, wherein the aforementioned reducing particles contain preservative components in addition to reducing components.

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