TW202348748A - surgical marking ink - Google Patents

Abstract

To provide a novel ink which is composed of only biocompatible components, satisfies the required characteristics necessary for a surgical ink, and can be suitably used as an ink for a surgical pen. An ink comprising at least a colorant, a dispersion medium, and a water-soluble polymer having a viscosity average molecular weight of 1,000-220,000, wherein the colorant is a carbon material, the pH of the ink is 4.0-11.0, the content of the water-soluble polymer is 20-200 parts by weight per 100 parts by weight of the colorant, and 50 wt% or more of the liquid constituting the ink is water serving as the dispersion medium.

Description

surgical marking ink

The present invention relates to surgical markings for performing surgical markings on the surface of the skin or on the surface or inner surface or cross section of incised skin tissue, organs, muscles, oral cavity, tongue, bones, etc. during medical procedures such as surgery. ) is a surgical ink (surgical ink) that can be better used.

In surgery, especially surgical operations, in order to confirm the location of the diseased part, resection site, blood vessels and nerves, etc., as well as to transmit information between doctors and nurses and record and confirm the surgical sequence, it is generally performed on the skin epidermis and muscles, Marking of lines, dots, numbers, and characters with surgical ink on living bodies such as bones and organs. Methods include marking the target site using a bamboo skewer or pen with the tip impregnated with ink, writing using a pen-like surgical writing instrument (surgical pen) filled with ink, and injecting the ink into the target site with a syringe or the like. Methods, etc., and inks and instruments used therefor are disclosed in, for example, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, and the like.

Examples of the main required characteristics of a surgical ink include the ability to remain fixed to the surface without flowing even to areas covered with oil/moisture content such as blood, sweat, body fluids, etc., and the ability to dry quickly after being fixed without causing friction or friction. Dryness that allows it to bleed, water resistance that does not easily dissolve or deteriorate with body fluids or physiological saline, color development that enables visibility required for surgery, and gamma rays that do not denature even when gamma rays are irradiated for disinfection. Resistance, low irritation by adjusting the pH to the optimum for the site to be applied, and in vivo compatibility that does not cause adverse effects on the human body and is made only of non-toxic/safe materials. Although we strive to have surgical inks that meet as many of these required properties as possible, fixation, color development and in vivo compatibility are particularly important. In addition, in order to be used for marking the skin epidermis where the marked area is clearly visible, it is necessary to have an erasing method that does not deposit pigment and can be easily wiped with gauze or the like to easily remove the staining without leaving traces after surgery. In addition, when used as an ink for surgical pens, it must also ensure that the fine flow path inside the pen can be ejected stably without clogging, and the ink must not deteriorate, solidify, separate, or precipitate even if it is stored for a long time. Long-term stability of ejection properties.

However, there is currently no device that meets these requirements and can perform well on the surface or inner surface, cross-section, etc. of a wide range of parts such as the skin epidermis or incised skin tissue, organs, muscles, oral cavity, tongue, bones, etc. It is a high-performance surgical ink suitable for use as a surgical ink.

For example, conventional surgical inks represented by Patent Document 1 and Patent Document 2 use methylrosanilinium chloride and methylene blue as color materials because of their high color development and ejection properties. However, this is not the same as in recent years. It has been pointed out that it may be carcinogenic and may cause chromosomal abnormalities. In vivo compatibility is not guaranteed. As a surgical ink that does not use succinylcholine chloride and methylene blue, there is disclosed a surgical ink that uses food coloring as a color material (Patent Document 3). However, since the color material used is a dye, it has problems with fixation and water resistance. Insufficient in nature, bones, muscles, organs, etc. covered by body fluids such as blood or physiological saline cannot be well marked because they will leak, dissolve, flow, etc., and the use for surgical purposes is limited to the skin epidermis and Marking of items such as towels that will not get wet.

In addition, inks represented by Patent Document 4 and Patent Document 5 are mainly used by injecting a syringe or the like into a target site. It is assumed that the ink is retained in the living tissue and does not contain components that form a film when it comes into contact with the outside air. There is a risk that the fixation, water resistance, and drying properties will be insufficient, and the coated ink will easily flow/dissolve. Therefore, it is not suitable for marking parts of bones and muscles where ink cannot be injected. In addition, the dispersion state and particle size of the color material cannot be adjusted to be suitable for use as a surgical pen, and there is a risk of causing ejection failure when used as a pen. In addition, the method of injecting ink with a syringe cannot draw thin lines and curves at will, so it is impossible to write letters, numbers, etc., and its use is limited.

Edible inks used for food, etc. have biocompatibility, but such inks cannot meet the required characteristics as surgical inks and are not suitable. For example, edible printing ink for food, etc. is designed on the premise of printing on a printed object whose surface state has been fixed in advance through surface treatment such as coating or baking, and is applied to the object according to the location and conditions. In surgical applications with different surface conditions, it is considered that the performance of fixation, color development, etc. cannot be fully exerted. In particular, inks that are mainly used for printing on dried objects to be printed are considered to be difficult to use during surgery because the ink is dissolved and flows due to blood covering the living body or physiological saline used for cleaning. Implement necessary markup. Moreover, these edible inks are based on the premise that they can be digested in the body, without considering the erasability, water resistance and low irritation of the printed object. Although cosmetic ink meets the requirements of in vivo compatibility and skin irritation for skin epidermis, etc., it is of course not considered when used on cut muscles, organs, and bones, and may cause adverse effects on the body. In addition, it is assumed that the ink can be washed away by strong friction using soap etc. during cleaning. Although it is designed to be very water-resistant and highly fixable, it is considered that it is not suitable as a surgical ink because it cannot be washed at the surgical site. Necessary erasure. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 5888658 [Patent Document 2] US2019/125483 Al [Patent document 3] Japanese Patent Publication No. 63-044788 [Patent Document 4] Japanese Patent Application Publication No. 2007-262062 [Patent Document 5] Japanese Patent No. 5099815

[Problem to be solved by the invention]

The purpose of the present invention is to eliminate the above-mentioned problems of the prior art. That is, the object of the present invention is to provide a novel ink that is composed only of certain components that are biocompatible, meets the required characteristics as a surgical ink, and is also suitable for use as an ink for a surgical pen. [Means used to solve problems]

Therefore, the inventors of the present invention have actively examined in order to achieve the above object, and found that by using a carbon material and adding a specific polymer material to an ink mainly containing water as a dispersion medium, and adjusting the pH within a specific range, an ink can be obtained. The present invention was completed by creating an excellent ink that is composed only of a certain component that is compatible with the living body and satisfies the required characteristics as a surgical ink and surgical pen ink. In addition, it was found that by adding appropriate specific alkaline substances or organic solvents, or adjusting the dispersed particle size, an ink that can exhibit better performance as a surgical pen ink can be obtained.

That is to say, the present invention provides (1) A surgical ink, which is characterized by at least including a color material, a dispersion medium and a water-soluble polymer ink with a viscosity average molecular weight of 1,000 to 220,000. The aforementioned color material is a carbon material, and the pH of the ink is 4.0 to 11.0. The aforementioned water-soluble polymer The content of the organic polymer is 20 to 200 parts by weight based on 100 parts by weight of the color material, and the dispersion medium includes more than 50% by weight of water of the liquid constituting the ink. (1) The ink of (1), wherein the aforementioned carbon material is activated carbon. (3) The ink as described in (1) or (2) above, wherein the ink contains 5% to 30% by weight of a water-soluble organic solvent. (4) The ink as in the above (3), wherein the water-soluble organic solvent includes at least one of ethanol, isopropyl alcohol, polyethylene glycol, propylene glycol and glycerin. (5) The ink according to any one of the above (1) to (4), wherein the average dispersed particle size of the aforementioned carbon material is 50 nm~1 μm. (6) The ink according to any one of the above (1) to (5), wherein the ink liquid contains 0.01 to 1.00% by weight of at least one of sodium carbonate and sodium hydroxide. (7) The ink described in any one of the above (1) to (6) is an ink for surgical pens. (8) A cosmetic ink made of the ink according to any one of the above (1) to (7). (9) An edible ink made of the ink according to any one of the above (1) to (7). (10) A method for manufacturing ink according to any one of the above (1) to (9), characterized by adding 0.01 to 1.00% by weight of an alkaline substance based on the total weight of the ink. (11) The production method of (10) above, wherein the alkaline substance includes at least one of sodium carbonate and sodium hydroxide. (12) The production method of (11) above, wherein the alkaline substance is sodium hydroxide. [Effects of the invention]

Since the ink of the present invention satisfies the characteristics required as an important surgical ink, it can be applied to the surface, inner surface, and cross-section of a wide range of parts such as the skin epidermis or incised skin tissue, organs, muscles, oral cavity, tongue, bones, etc. etc., and can be used as surgical markers in a wide range of surgeries. In addition, since it also has suitable physical properties as an ink for surgical pens, by filling it in the pen and using it, the width of the drawing line from thin to thick can be adjusted, and any drawing line, text, or number can be written smoothly and stably. , marks, etc., which have the advantage of convenience.

The ink of the present invention is characterized in that it contains at least a color material, a dispersion medium and a water-soluble polymer, and uses a carbon material as the color material. [Carbon material] The present invention is characterized by the use of carbon materials. As the carbon material used in the present invention, those having biocompatibility can be widely used, and activated carbon, carbon black, graphite, graphite, graphene, fullerene, etc. can be preferably used. Since these carbon materials have excellent visibility, in addition to achieving the color rendering required for surgery, they also have in vivo compatibility. In addition, the inventors found out through examination that by using a carbon material as a color material, gamma ray resistance can be imparted to the ink. Although the mechanism is not completely clear, it is speculated that the carbon material dispersed in the ink blocks gamma rays and prevents deterioration of other components such as water-soluble polymers. This effect is particularly obvious when the carbon material is activated carbon and the water-soluble polymer is polyvinylpyrrolidone. Among these carbon materials, activated carbon, which is particularly excellent in coloring properties and dispersibility and can be obtained relatively cheaply, is preferably used. Moreover, these carbon materials may be used individually by 1 type, or may be used in combination of 2 or more types.

[Activated Carbon] Activated carbon is a black porous powder that is generally used for deodorization, water purification, wastewater treatment, catalyst support, etc. by utilizing its pores. In particular, purified activated carbon is taken as medicinal carbon to absorb gases or toxic substances in the intestines and eliminate them from the body. In the present invention, activated carbon, which is generally not used as a color material, is used as the black color material. Activated carbon is known as a carbon material with a very large specific surface area. By heating carbon materials such as wood, so-called carbon such as binchotan can be obtained (this step is called "carbonization"), but the specific surface area of carbon (including powdered ones) is generally said to be 300~ ^500m2 /g. On the other hand, activated carbon is known to have a specific surface area of 800 to 2000 m ² /g and further to 500 to 3000 m ² /g by treating the carbon at a high temperature near 1000°C (in this way, the carbon material is The step of treating it at high temperature to increase the specific surface area and turn it into activated carbon is called "activation" or "activation reaction"), and it becomes one with extremely high adsorption performance.

Generally, activated carbon is made from carbon materials such as coal or coconut shells as raw materials, which react with gases or chemicals at high temperatures. Although the chemical activation method of impregnating the raw materials with zinc chloride solution and then heating and activating it under certain conditions, and the water vapor activation method of activating the raw materials and heated water vapor at a temperature of 800~1000°C are known, this method In the invention, the manufacturing method of activated carbon is not particularly required. Activated carbon is roughly divided into three types according to raw materials, namely, "coal-based", "plant-based" and "others", but it can be used without particular restrictions in the present invention.

In addition, it is roughly divided into powder activated carbon and granular activated carbon according to its shape. Powdered activated carbon refers to powder with a particle size that can pass through a sieve of 100 mesh (mesh opening 0.15mm), and granular activated carbon refers to one with a particle size that does not pass the sieve. In addition, as special shapes, there are fibrous activated carbon and special shaped activated carbon (honeycomb shape, plate shape (sheet shape)). In the present invention, powdered activated carbon is preferably used because it is finer and has excellent dispersibility/colorability.

The physical properties of the activated carbon used in the present invention are not particularly limited, but generally the average particle size is 1 to 100 μm, and preferably 5 to 70 μm. The specific surface area is not particularly limited, but is preferably 500 to 3000 m ² /g, and particularly preferably 1000 to 2000 m ² /g. The total pore volume is not particularly limited, but is preferably 0.3 to 5 ml/g, more preferably 0.5 to 4 ml/g, and most preferably 0.5 to 3 ml/g.

The average pore diameter is preferably 1 to 20 nm, and particularly preferably 2 to 10 nm. The pH of activated carbon is preferably 3 to 8, and particularly preferably 4.5 to 7.5. The iron content in the activated carbon is preferably 0.03% by weight or less, particularly preferably 0.01% by weight or less. The pH, average particle size, specific surface area, total pore volume, average pore diameter, and iron content were measured using the method of JIS K 1474-91.

In addition, the activated carbon used in the present invention is preferably based on the method described in JIS K 1474-91 and the official document on food additives. The chloride (calculated as Cl) is preferably 0.53% or less, and the sulfate (calculated as SO ₄ ) It is 0.48% or less, zinc is 0.10% or less, and arsenic (calculated as As ₂ O ₃ ) is 4.0 μg/g or less. If it is within this range, it is non-toxic to the human body because it complies with food additive standards, and can prevent impurities from affecting the physical properties of the ink.

The blending amount of activated carbon in the ink is preferably 0.1% to 10% by weight, preferably 0.5% to 8% by weight, and more preferably 1% to 5% by weight. When the content is less than 0.1% by weight, the concentration of the colorant is relatively thin, and the color development property of the ink may be insufficient. When it exceeds 10% by weight, the stability over time is poor due to aggregation of activated carbon, and the ejection properties of the self-marking pen are further reduced, making it difficult to write stably.

[Water-soluble polymer] The present invention is characterized by containing water-soluble polymers with a viscosity average molecular weight of 1,000 to 220,000. Generally, in order to produce a liquid composition in which solid fine particles such as pigments are dispersed in a liquid medium, a compound called a dispersant is added. These are compounds that have the function of stably dispersing solid particles such as pigments in a dispersion medium. If roughly distinguished, they can be roughly divided into relatively low molecular weight compounds called surfactants and higher molecular weight polymer compounds.

Among them, polymer compounds generally have the following forms: they have many hydrophilic groups in the molecular chain, and are dissolved when hydrated with water molecules; long-chain aminoamides, acrylic acid, polycarboxylic acids and their salts are the main ones The structure is a soluble form of a neutralized salt having an alkaline form such as a amide or amine as an adsorption group adsorbed on solid microparticles, or an acidic group such as a carboxyl group or a phosphate group. Compared with these general solid microparticle dispersion methods, the characteristic of the present invention is to stably disperse the carbon material of the solid microparticles by formulating a polymer that is water-soluble and has a viscosity average molecular weight of 1,000 to 220,000. It is not limited to those specifically known as dispersants.

The viscosity average molecular weight of the water-soluble polymer is 1,000~220,000, preferably 2,000~100,000, more preferably 5,000~100,000, most preferably 7,000~50,000. If the viscosity average molecular weight is less than 1,000, the ink will not be filmed during writing and will not be fixed to the writing object. When the viscosity average molecular weight exceeds 220.000, the fixation to the writing object becomes stronger and the erasability required as a surgical ink cannot be obtained. The determination of viscosity average molecular weight is basically based on the molecular weight determination method described in Polymer Papers, Volume 38, Issue 7, Pages 457-463 (July 1981). That is, borrow the following order.

(1) Add the sample to excess acetone for precipitation purification. After repeating this operation twice, dry under reduced pressure until the smell of acetone disappears. (2) Prepare an aqueous solution of the purified sample, use an Ubbelohde viscometer (water, 120 seconds), and calculate the viscosity average molecular weight using the Mark-Kuhn-Houwink formula (Mark-Houwink-Sakurada formula). The coefficients M and α of the Mark-Kuhn-Houwink formula are those described in the above-mentioned collection of polymer papers. However, it does not matter if the same result can be obtained by other methods.

In addition, the molecular weight value may vary by approximately 10% due to measurement errors, etc. Therefore, it does not matter if it is within a range of approximately 10% of the above numerical range.

As the water-soluble polymer used in the present invention, nonionic polymers are particularly preferably used. As an indicator of polarity, there is acid value. In the present invention, the acid value is preferably 30 mgKOH/g or less, more preferably 20 mgKOH/g or less, and more preferably 5 mgKOH/g or less. It is best that the acid value cannot be detected at all (the acid value is essentially Above is 0mgKOH/g). Within this range, the dispersion performance of the carbon material and the water resistance of the ink are particularly excellent.

The determination of acid value is based on the method of DIN53402, more specifically as follows. (1) Weigh 0.9~1.3g of the sample into a beaker. (2) Add 50ml of acetone. (3) Measure with an automatic potentiometric titration device using a 0.1N NaOH aqueous solution. Automatic potentiometric titration device The results are the same regardless of which device is used. (4) Calculate the amine value according to the following calculation formula.

Acid value=[(a-b)×5.61]/E(mgKOH/g)

a: The number of ml of 0.1N NaOH required for titration b: The number of ml of 0.1N NaOH required for blank titration E: Sample weight (g) (5) Expression: Express to the first decimal point.

Specific examples of the above water-soluble polymers include acrylic polymers with acid values such as casein, water-soluble cellulose derivatives, polyvinylpyrrolidone, styrene acrylic acid, etc. Water-soluble polymers with carboxylic acid groups can be used. Choose appropriately according to the object being written.

As the above-mentioned water-soluble cellulose derivative, cellulose ethers substituted with alkyl groups and hydroxyalkyl groups or cellulose ethers substituted with hydroxyalkyl groups can be preferably used.

Among the above water-soluble polymers, non-polar water-soluble polymers such as hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and polyvinylpyrrolidone are particularly preferred. These have excellent fixability to the object to be coated, and are excellent in drying properties since they form a film when in contact with the outside air. Furthermore, since the formed film is water-soluble, they are also excellent in erasability. In addition, it is possible to provide an ink that has excellent dispersion properties and excellent dispersion stability and ejection properties when used as an ink for surgical pens.

These water-soluble polymers have good fixation to the skin epidermis or incised subcutaneous tissue, organ surfaces, muscles, bones, oral cavity, tongue, etc. and can be used appropriately. The best among them is polyvinylpyrrolidone, which has excellent fixation properties, is widely regarded as a food additive, has in vivo compatibility, exhibits resistance to gamma rays through interaction with activated carbon, and has high dispersion properties.

The added amount of the water-soluble polymer is characterized in the present invention and is 20 to 200 parts by weight relative to 100 parts by weight of the carbon material. More preferably, it is 25 to 180 parts by weight, and most preferably 30 to 150 parts by weight. When it is less than 20% by weight, it is difficult to fully disperse the color material, and the dispersed particle size of the carbon material in the dispersion medium becomes large. When used as a surgical pen, there is a risk of clogging inside the pen, etc., causing poor ejection. When the content exceeds 200 parts by weight, the viscosity of the ink becomes high, so the ink becomes difficult to eject from the pen core, resulting in decreased writing properties.

It was found that the ink of the present invention can be stably and finely dispersed by blending the specific water-soluble polymer described above, and can be suitably used as a surgical ink. Moreover, by blending these specific water-soluble polymers, the carbon material has excellent color tone, improved adhesion when writing on the surgical site, good fixation of the writing object, and will not be erased during surgery. , can perform excellent black writing that can be erased by wiping with wet gauze. Although the mechanism for obtaining such excellent effects is not completely clear, it is speculated that the good affinity with the porous fine powder carbon material and the polar interaction with the particle surface of the carbon material effectively contribute to preventing the ink from forming. Aggregation in the medium stabilizes the particle state.

[dispersion medium] The characteristic of the present invention is that water is used as the main body as the dispersion medium. By using water as the main body, it can become an ink with excellent biocompatibility, safety, and operability. In the composition of the ink of the present invention, even when water is used as the main dispersion medium, the dispersion state remains stable, and the ejection property of the surgical pen during writing can be stably maintained. The water used in the present invention is not particularly limited, but is preferably distilled water and water for injection that have been appropriately quality-controlled for medical use. The term "water as the main body" here means that more than 50% by weight, more preferably more than 60% by weight, of the liquid constituting the ink is water. That is, in the present invention, more than 50% by weight of the liquid constituting the ink is water. Particularly preferred is a composition in which the liquid component other than the specific water-soluble organic solvent described below is substantially water. If the present invention contains water in an amount greater than the above-mentioned amount, a dispersion medium may be included in addition to water and a water-soluble organic solvent. In this case, the liquid is not particularly limited as long as the carbon material can be dispersed, and it can be appropriately selected according to the use.

[Water-soluble organic solvent] In the present invention, it is desirable to contain a specific water-soluble organic solvent as a liquid component other than water. By adding these water-soluble organic solvents, when writing with a surgical pen, especially a marker-type surgical pen, in addition to preventing partial clogging of the pen core, the dryness of the ink can also be adjusted according to the structure of the pen. Specific examples of such water-soluble organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, trimethylolpropane, and ethylene glycol. Monoethyl ether, ethylene glycol monobutyl ether, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thiodiol Alcohol, hexanediol, glycerin, diglycerol, 1,2-hexanediol, 1,6-hexanediol, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,5-pentanediol, monoethyl Glycol monomethyl ether, monoethylene glycol monoethyl ether, monoethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol monobutyl ether Ether, triethylene glycol monoethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, methyl lactate, ethyl lactate, 1,3-dimethyl-2-imidazolinone, etc. Can be used alone or in combination of 2 or more types. As food additives, Tejia is suitable for ethanol, isopropyl alcohol, polyethylene glycol, propylene glycol, glycerin, etc.

The amount of the water-soluble organic solvent added to the ink in the form of the present invention is preferably 5 to 35% by weight. More preferably, it is 10% by weight to 30% by weight. If it is added in an amount of more than 35% by weight, the ink will become highly viscous, and the stability and ejection properties of the ink will be reduced, and the drying speed may also be slowed down. If the content is less than 5% by weight, the ejection of the refill may be unstable when used as a surgical pen, and may cause slippage or clogging, resulting in reduced writing properties.

[Surface tension adjuster] In the present invention, a surface tension modulator can be used as necessary. The surface tension modulator is a component that improves the ejection properties of the pen core and adjusts the surface tension. Specific examples of the surface tension modulator are preferably anionic, nonionic, etc. surfactants, and specific examples include alkyl benzene sulfonates, higher alcohol sulfate ester salts, higher fatty acid salts, and higher alkyl dicarboxylic acids. Anionic surfactants such as salts, alkyl naphthalene sulfonates, alkyl sulfosuccinates, naphthalene sulfonate formaldehyde condensate salts, polyoxyethylene alkyl ether sulfates, polyethoxyethylene alkyl phosphates, etc. ;For example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, fatty acid monoglyceride, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene Non-ionic surfactants such as fatty acid esters, glycerol fatty acid esters, polyoxyethylene-added acetylene glycol, etc., silicone-based surfactants, fluorine-based surfactants, water-soluble organic solvents such as ethanol and isopropyl alcohol . The amount of surface tension adjuster added can be appropriately selected according to the required surface tension, but it is preferably 0.5 to 30% by weight in the ink, and particularly preferably 1 to 20% by weight.

[alkaline substance] In the present invention, in order to adjust the pH within a specific range, an alkaline substance may be present in the ink. In the ink composition of the present invention, the carbon material tends to make the ink acidic. Therefore, if the ink is not neutralized with an alkaline substance, the irritation to the living body may become stronger depending on the location. The suitable pH range of a living body varies depending on the site. However, in the present invention, by appropriately adjusting the amount of alkaline substances added, the pH can be adjusted to an appropriate range according to the site to be marked, thereby reducing irritation. The alkaline substance of the present invention is not particularly limited as long as it is alkaline in the definition of Arrhenius and has biocompatibility. However, it is preferably one that can significantly change the pH by adding a small amount. , and then become a pH adjuster for edible sodium carbonate, sodium hydroxide, potassium carbonate, sodium bicarbonate, etc. Among them, sodium carbonate and sodium hydroxide are particularly preferred, and sodium hydroxide is the most preferred.

Especially when used as an ink for surgical pens, sodium hydroxide is the most preferred among these. By adding sodium hydroxide, even for difficult-to-disperse pigments such as activated carbon, the dispersed state of particles in the ink remains stable, preventing ejection failures such as clogging of the pen tip and deterioration, sedimentation, etc. caused by long-term storage. Curing, granulation increasing, viscosity increasing, etc. The mechanism by which sodium hydroxide contributes to the stabilization of the dispersed state is not yet clear, but it is thought that the surface active stabilization of carbon material particles exhibits the effect of preventing aggregation.

The alkaline substance preferably contains 0.01~1.00 parts by weight in 100 parts by weight of the ink, and more preferably contains 0.05~0.50 parts by weight. If the alkaline substance is less than 0.01 parts by weight, the pH change will be insufficient, and the effect of stabilizing the dispersed state cannot be fully demonstrated when sodium hydroxide is used. If the amount added is more than 1.00 parts by weight, the pH will exceed the range suitable for living organisms and the pH will be high, resulting in strong stimulation.

In addition, for other purposes such as adjusting the viscosity of the ink, improving adhesion, etc., other components such as water-soluble polymers may be appropriately added within the range that does not hinder the performance of the present invention. For example, starches such as guar gum, locust bean gum, agar, and methyl starch, gelatin, amylopectin, xanthan gum, tragacanth gum, dextrin, casein, and water-soluble cellulose derivatives may also be added. Non-polar water-soluble polymers such as polyvinyl alcohol and polyvinylpyrrolidone.

Furthermore, although the ink of the present invention is characterized by containing a carbon material as a color material, it does not matter if it contains other color materials as long as it does not impede the performance of the present invention.

[Characteristics of ink] The average dispersed particle size of the carbon material in the ink of the present invention is 50nm~1μm, preferably 50~800nm, more preferably 50~700nm, more preferably 50~600nm, still more preferably 50~500nm, and still more preferably 50~500nm. More preferably, it is 100~450nm, and the most optimal is 150~400nm. Within the above-mentioned preferred range, the tinting strength, dispersion stability, fixation, and ejection properties are excellent. However, in the ranges of 50~500nm, 100~450nm, and 150~400nm, the above-mentioned properties are exceptional regardless of the pen components or refills. Excellent. When the average dispersed particle size is less than 50 nm, aggregation is likely to occur due to van der Waals forces between particles, and the stability tends to decrease over time. When the average dispersed particle size exceeds 1 μm, the color material in the liquid is likely to separate and may easily cause precipitation.

Furthermore, it is preferable to control not only the average dispersed particle size but also the amount of coarse particles. Specifically, if more than 90% of the total carbon material particles in the liquid are adjusted to have a dispersed particle size of 1 μm or less, and more preferably 500 nm or less, ink with better physical properties can be obtained. As an adjustment method, it is also considered to conduct dispersion treatment until more than 90% of the total carbon material particles have a dispersed particle size of 1 μm or less, more preferably 500 nm or less. However, in order to prevent a large number of excessively fine particles from being reaggregated, the dispersion treatment is performed until evenly dispersed After the particle size is 1 μm or less, more preferably 500 nm or less, conventional methods such as centrifugation or filter filtration to remove coarse particles are also suitable.

In addition, in the present invention, the method for measuring the average dispersed particle size and the dispersed particle size of all particles is as follows, but if the same result can be obtained, it is not limited to this. Conditioning: Dilute the original solution with ion-exchange water so that it falls into the measurement concentration area specified by each measurement machine. Measuring machine: Dynamic light scattering particle size distribution analyzer ("NIKKISO: Microlracwave-EX150") Measurement time: 120 seconds

The viscosity of the ink of the present invention is preferably 1.0~10.0mPa·s. More preferably, it is 1.5~9.0mPa·s, and most preferably, it is 2.0~8.0mPa·s. When the viscosity is less than 1.0 mPa·s, too much ink may flow out of the pen core when used as a surgical pen. On the contrary, when the viscosity exceeds 10.0 mPa·s, the ink will not easily flow out of the pen core, causing blurring. In addition, when using a marker-style pen that generally uses pigmented ink, if the pen tip is stored for a long time, the pigment will precipitate and accumulate near the pen tip, solidifying, causing the pen tip to become clogged, resulting in blurry/light-colored writing. There is a risk of reduced writing properties, but by increasing the viscosity of the ink within the above range, the speed of pigment precipitation can be reduced, thereby suppressing the deterioration of writing properties.

The measuring method of viscosity in the present invention is as follows, but it is not limited to this if the same result can be obtained. Adjustment: stock solution Measuring equipment: Cone plate type rotational viscometer ("TVE-20L type" manufactured by Toki Industrial Co., Ltd.) Measurement conditions: 50rpm Measuring temperature: 25℃

The ink of the present invention is characterized by a pH value of 4.0 to 11.0. Outside this range, it cannot be used as surgical ink because it is highly irritating to living organisms. In most parts of the living body, a pH of 6.0 to 9.0 is preferred, but irritation can be reduced by adjusting to an appropriate value according to the part to be coated. The method of measuring pH is not particularly limited, but can be performed as follows. Adjustment: stock solution Measuring device: pH meter ("MH-41X type" manufactured by DKK East Asia Co., Ltd.) Measuring temperature: 25℃

The ink of the present invention can be resistant to gamma rays. That is, as shown in the examples described below, the physical properties of the ink of the present invention hardly change before and after gamma rays, and the ink can maintain stable quality for a long time even after gamma ray irradiation. Specifically, according to JIS/ISO standards (JIS T 0806-1/ISO 11137-1 and JIS T 0806-2/ISO 11137-2), even after gamma ray irradiation treatment with an absorbed dose of 25 kGy to 70 kGy, the average dispersed particles The diameter, viscosity, and pH can still be maintained within the aforementioned optimal ranges, and the average dispersed particle size, viscosity, and pH can be maintained within the aforementioned optimal ranges. As mentioned above, it is speculated that by including the carbon material, the carbon material can shield gamma rays and prevent other components such as water-soluble polymers from deteriorating. This effect occurs when the carbon material is activated carbon and the water-soluble polymer is The situation of polyvinylpyrrolidone is particularly remarkable. This was also found out by the inventors' review and can also be confirmed by the examples described below. By having gamma ray resistance, the ink will not deteriorate even if it is irradiated with gamma rays to sterilize the surgical pen, maintaining optimal physical properties as a surgical ink, and marking and writing can be performed without problems such as poor ejection. .

The absorbed dose of 25kGy~70kGy is a dose common to the surgical ink of the present invention and the surgical pen using it to ensure sterility, and is based on sterilization verification (JIS T 0806-1/ISO 11137-1 and JIS T 0806-2/ISO 11137 The regulations of -2) are determined through (1) material test, (2) bioburden measurement, (3) sterilization dose setting test, (4) sterility test, and (5) dose distribution evaluation. (1) Bioburden determination and (4) Sterility test are based on the JIS/ISO standards "Method for determination of microbial colonies on products" (JIS T 11737-1/ISO 11737-1) and "Definition, verification and verification of sterilization processes" respectively. Sterility test performed during maintenance" (JIS T 11737-2/ISO 11737-2). That is, the sterility assurance level (SAL) is 10-6, based on the number of viable microorganisms per unit of irradiated object obtained through (1) bioburden determination and (4) sterility test. The lethal speed (the time required to reduce the number of bacteria to 1/10: D value) determines the absorbed dose of gamma rays that reaches SAL. In other words, in order to ensure sterility, the γ-ray irradiation time is longer than the time required to achieve the γ-ray absorbed dose to achieve SAL (about 2 to 3 hours). In the present invention, the absorbed dose is set to 25kGy~70kGy, more preferably 25kGy~45kGy. When the absorbed dose is less than 25 kGy, sterility cannot be ensured. When it exceeds 70 kGy, radiation deterioration is accelerated and the properties of the ink may be inadvertently denatured. The absorbed dose range of 25kGy~70kGy is set to correspond to the error in the relative distance between the position of each sterilized object in the box and the line source, and is set to ensure that the surgical pen filled with the surgical ink of the present invention is (4) The sterility of the sterility test and the range of the mechanical strength of the (1) material test are guaranteed.

The ink of the present invention is preferably subjected to gamma ray irradiation treatment after the ink is produced. Specifically, it is better to perform gamma rays with an absorbed dose of 25kGy~70kGy according to JIS/ISO standards (JIS T 0806-1/ISO 11137-1 and JIS T 0806-2/ISO 11137-2) after the ink is produced. For irradiation treatment, the optimal absorbed dose is 25kGy~45kGy. By performing gamma ray irradiation treatment within the above range, the ink can be sterilized, and the ink can be guaranteed to be safe for use in surgeries, and it is less likely to change the physical properties of the ink due to radiation degradation and is less likely to cause the surgical pen to be filled. Mechanical strength is reduced. The method and conditions used in the gamma ray irradiation treatment are not particularly limited as long as they meet the above standards, but the gamma ray irradiation treatment can be performed as follows. ・γ-ray irradiation treatment: Radioactive nuclide: Co60 Irradiation facility: Nippon Irradiation Services Co., Ltd., inside Tokai Center Irradiation container: box (78×50×150cm) Irradiation device: (Type) JS10000HD, IR-199 (Manufacturing source) MDS Nordion Set target absorbed dose: 50kGy (actual measured value 54.0kGy~67.6 kGy) Irradiation time: 26,000 seconds

The ink of the present invention can have physical properties that do not deteriorate even if stored for a long period of time. Specifically, when stored at room temperature, preferably after more than 30 days after production, the average dispersed particle size, viscosity, and pH are within the above-mentioned preferred ranges, and more preferably after more than 60 days, these are within the above-mentioned preferred ranges. Within the range, it is best that even after more than 90 days have passed, they can still be within the above-mentioned better range. Since the above-mentioned physical properties can be maintained within an optimal range even during long-term storage, even when filled in a pen and stored, the ejection properties and writing feel are not impaired, and stable writing is possible with low irritation.

[Making of Ink] The manufacturing method of the ink of the present invention is not particularly limited, as long as the above-mentioned components are mixed to prepare the ink. As an example, the carbon material, water-soluble polymer and water are mixed and stirred, and then dispersed using a commercially available disperser such as a paint vibrator, roller mill, ball mill, sand mill, jet mill, etc., and then the above instructions are appropriately added. Various additives such as water-soluble organic solvents and surface tension adjusters are used to form inks. Furthermore, the quality can be further improved by subjecting the ink produced as described above to filter treatment, magnetic separation treatment, impurity ion removal treatment, etc. by conventional methods. In addition, in the above-mentioned manufacturing method, after the carbon material, water-soluble polymer and water are mixed, stirred and dispersed, a step of removing coarse particles is also added, so that ink that is stable and maintains a well-dispersed state can be effectively manufactured. When adding an alkaline substance, the method and time are not particularly limited. For example, it is added together with water, carbon materials, and water-soluble polymers when they are mixed and stirred, or added together with additives such as water-soluble organic solvents and surface tension adjusters after dispersion treatment. When the gamma ray irradiation treatment is performed, it is performed after the ink is produced as described above. The ink can also be placed in a container that is resistant to gamma rays, such as a polyethylene container, and then irradiated with gamma rays, or it can be filled into any pen to make a surgical pen.

[How to use and purpose] Using the ink of the present invention described above, it is possible to apply and write on various objects. For example, surgical marking can be performed by attaching the ink of the present invention to the tip of a bamboo skewer, cotton swab, pen, scraper, etc., and applying it to the area to be marked. Furthermore, by filling in the surgical pen and writing, the line width and point size can be adjusted, allowing for more precise marking. When used for surgical pens, the type of pen and writing method are not particularly limited. Writing tools such as markers, roller pens, and plastic pens that have been used as stationery in the past can be sterilized and used. However, in terms of writing properties, it is better to use The pen components do not deteriorate even after gamma ray irradiation treatment, ensuring sufficient mechanical strength and ejection properties of the pen. Among pens, pens in the form of marker pens have particularly fine ink flow paths, and inks using pigments tend to have problems with writing properties such as ejection properties. However, in the present invention, by combining the aforementioned structures, it is possible to demonstrate a suitable It has the physical properties of writing, so it can be used better. Since the ink of the present invention is composed only of ingredients that are biocompatible and can be safely ingested in the body, it can also be preferably used in applications other than surgical inks that require biocompatibility, such as cosmetics, sanitary products, Writing, decoration, printing, etc. for food, toys, baby products, pharmaceuticals, etc. In addition, because it has excellent coloring and fixing properties, it can be used for various purposes such as anti-counterfeiting, traceability recording, display of precautions such as accidental ingestion, improvement of visibility, design and entertainment, etc. use. [Example]

The following examples illustrate the present invention in detail. In the examples, "parts" all represent parts by weight.

[Example 1] ・Manufacture of dispersion liquid Prepare the ingredients shown below and stir with a propeller mixer at room temperature for 1 hour. Ingredients Quantity (Parts by weight (hereinafter referred to as parts)) Activated carbon 10.0 (Average particle size: 35μm, average pore diameter: 3.4nm) Polyvinylpyrrolidone 7.22 (Viscosity average molecular weight; 50,000) Water 82.78

Next, 150 g of zirconia beads with a diameter of 0.5 mm were placed into a paint shaking pot for the resulting mixture and vibrated for 3 hours. The coarse particles contained in this dispersion were removed, and the dispersed particle diameter of more than 90% of the total particles was adjusted to 500 nm or less, and the solid content concentration was 10% by weight, which was designated as "dispersion 1".

・Ink Secondly, stir the following mixture with a propeller mixer at room temperature for 30 minutes to obtain ink. Ingredients Quantity (portions) Dispersion 1 (solid content 10%) 68.03 Propylene Glycol 5.0 Water 26.97 The average dispersed particle size of the obtained ink was 274 nm, the viscosity was 2.5 mPa·s, and the pH was 5.1. The resulting ink appears uniformly black. Furthermore, the above-mentioned ink was tested and evaluated for stability over time, writing properties, fixability, and water resistance according to the following methods. The results are shown in Table 1.

(a) Time stability test Put the ink in a polyethylene bottle and let it stand for 1 month in a constant temperature room at 25°C. Check whether there is separation, water floating and sedimentation of the colorless material. The state in which color materials separate, water floats, and settles slightly occurs is also evaluated as abnormal. In Table 1, if there is no abnormality, it is marked as ○. Although there is an abnormality, if the separation, water floating and sedimentation can be improved to the same degree as if there is no abnormality by gently stirring with a spoon, it is marked as △. If there is an abnormality and gently stirring with a spoon, it is marked as △. Those that cannot improve separation, water flotation, and sedimentation to the same level as no abnormality despite stirring are marked as ×.

(b) Writing test Fill the pen tip with ink into a cotton-wool type marker pen made of polyurethane resin bonded PET resin fiber bundles with a slightly hemispherical fiber bundle core (diameter 12mm) at the tip, and apply it on the dry back skin and chicken bones of the hand. While writing, check whether ink can be ejected from the pen core, whether the drawn line is visible, and whether writing can be continued after 30 minutes. If the ink can be ejected immediately after filling, the drawn line can be clearly recognized, and it can be written again even after 30 minutes, it is marked as ○ in Table 1. If any of these is not true, it is marked as ×.

(c)Fixity/drying test Fill the marker pen used in the above (b) writing test with ink, write on the dry skin of the back of your hand, wipe the writing part three times with a dry non-woven fabric, and check whether the ink stretches and whether the ink transfers to the non-woven fabric. When there is no ink stretching and no transfer to the nonwoven fabric, it is marked as ○ in Table 1. When any of these conditions are not satisfied, it is marked as ×.

(d) Water resistance test Fill the marker pen used in the above (b) writing test with ink and write on the dry skin of the back of your hand. After 10 minutes, rinse the writing part with tap water for 1 minute and check whether there is visibility of the written line and whether there is bleeding. . When the written and drawn lines are clearly visible and bleeding or spreading to the periphery is not confirmed, it is marked as ○ in Table 1. When either of these conditions is not satisfied, it is marked as ×. (e) Color development test In the test of (d), visually confirm the drawn line after writing to confirm whether the drawn line and color tone can be distinguished. Those that can be distinguished as black or even dark gray and have good drawing lines are marked as ○ in Table 1, and those that cannot be distinguished are marked as ×.

[Example 2] In Example 1, the ink was produced in the same manner except that the composition when converted into ink was as follows. Ingredients Quantity (portions) Dispersion 1 (solid content 10%) 68.03 Propylene Glycol 5.0 Ethanol 15.0 Water 11.97 The average dispersed particle size of the obtained ink was 313 nm, the viscosity was 4.3 mPa·s, and the pH was 4.9. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 3] In Example 1, the ink was produced in the same manner except that the composition when converted into ink was as follows. Ingredients Quantity (portions) Dispersion 1 (solid content 10%) 75.83 Propylene Glycol 5.0 Sodium carbonate 0.0064 Water 19.16 The average dispersed particle size of the obtained ink was 352 nm, the viscosity was 2.8 mPa·s, and the pH was 6.1. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 4] In Example 1, the ink was produced in the same manner except that the composition when converted into ink was as follows. Ingredients Quantity (portion) Dispersion 1 (solid content 10%) 75.83 Propylene Glycol 5.0 Ethanol 15.0 Sodium carbonate 0.0064 Water 4.16 The average dispersed particle size of the obtained ink was 300 nm, the viscosity was 5.1 mPa·s, and the pH was 6.2. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 5] In Example 1, a dispersion liquid was produced in the same manner as in Example 1 except that the preparation of the dispersion liquid was as follows. The obtained dispersion liquid was designated as "dispersion liquid 2". Ingredients Quantity Activated carbon 9.0 (Average particle size: 35μm, average pore diameter: 3.4nm) Polyvinylpyrrolidone 6.3 (Viscosity average molecular weight; 25,000) Sodium hydroxide 0.129 Water 84.571

The ink was produced in the same manner as in Example 1 except that the obtained dispersion 2 was used and the preparation of the ink was as follows. Ingredients Quantity (portions) Dispersion 2 (solid content 10%) 62.5 Propylene Glycol 25.0 Water 12.5 The average dispersed particle size of the obtained ink was 290 nm, the viscosity was 6.1 mPa·s, and the pH was 8.9. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 6] In Example 5, ink was produced in the same manner except that the composition when converted into ink was as follows. Ingredients Quantity (portions) Dispersion 2 (solid content 10%) 62.5 Propylene Glycol 20.0 Ethanol 5.0 Water 12.5 The average dispersed particle size of the obtained ink was 270 nm, the viscosity was 5.7 mPa·s, and the pH was 8.7. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 8] In Example 1, a dispersion liquid was produced in the same manner as in Example 1 except that the preparation of the dispersion liquid was as follows. The obtained dispersion liquid was designated as "dispersion liquid 3". Ingredients Quantity Activated carbon 9.0 (Average particle size: 35μm, average pore diameter: 3.4nm) Polyvinylpyrrolidone 6.3 (Viscosity average molecular weight; 40,000) Sodium hydroxide 0.129 Water 84.571

The ink was produced in the same manner as in Example 1 except that the obtained dispersion 3 was used and the preparation of the ink was as follows. Ingredients Quantity (portions) Dispersion 2 (solid content 10%) 62.5 Propylene Glycol 25.0 Water 12.5 The average dispersed particle size of the obtained ink was 346 nm, the viscosity was 7.7 mPa·s, and the pH was 9.2. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 9] In Example 5, ink was produced in the same manner except that the composition when converted into ink was as follows. Ingredients Quantity (portions) Dispersion 2 (solid content 10%) 62.5 Propylene Glycol 20.0 Ethanol 5.0 Polyvinylpyrrolidone 2.0 (Viscosity average molecular weight; 25,000) Water 10.5 The average dispersed particle size of the obtained ink was 307nm, the viscosity was 7.6mPa·s, and the pH was 8.0. The resulting ink is uniformly black in appearance. Furthermore, the above-mentioned ink was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative example 1] ・Manufacture of dispersion liquid Prepare the ingredients shown below and stir with a propeller mixer at room temperature for 1 hour. Ingredients Quantity (portion) Iron oxide red 10.0 Polyvinylpyrrolidone 8.5 (Viscosity average molecular weight: 40,000) Sodium carbonate 0.1 Water 81.4

Next, 150 g of glass beads with a diameter of 0.7 mm were placed in a paint shaking pot for the obtained mixture and vibrated for 3 hours. The coarse particles contained in this dispersion were removed, and the dispersed particle diameter of more than 90% of the total particles was adjusted to 500 nm or less, and the solid content concentration was 10% by weight, which was designated as "dispersion 3".

・Ink Secondly, stir the following mixture with a propeller mixer at room temperature for 30 minutes to obtain ink. Ingredients Quantity (portion) Dispersion 3 (solid content 10%) 50.0 Propylene Glycol 10.0 Water 30.0 The average dispersed particle size of the obtained ink was 452 nm, the viscosity was 5.5 mPa·s, and the pH was 8.2. The resulting ink appears uniformly black. Furthermore, the above-mentioned ink was tested and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative example 2] In Comparative Example 1, an ink was produced in the same manner except that the iron oxide red was black iron oxide. The average dispersed particle size of the obtained ink was 1130 nm, the viscosity was 5.4 mPa·s, and the pH was 9.1. And the obtained ink shows uniform black color in appearance. Furthermore, the above-mentioned ink was tested and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative example 3] In Comparative Example 1, an ink was produced in the same manner except that iron oxide red was used as a water-soluble black dye. The viscosity of the obtained ink was 4.2 mPa·s and the pH was 7.1. And the obtained ink shows uniform black color in appearance. Furthermore, the above-mentioned ink was tested and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Performance evaluation test on human epidermis writing] Next, in order to confirm more detailed performance, the ink obtained in Example 5 and the ink obtained in Example 5 were classified using a centrifuge, and the ink from which coarse particles were removed (referred to as "Example 7") was filled as follows. The pen is used to perform performance evaluation tests on human writing using the following methods (A) and (B). Fill the ink obtained in Example 5 into a cotton-wool-type marking pen with a fiber bundle core (diameter 12 mm) that is slightly hemispherical at the tip and is made of polyurethane resin bonded PET resin fiber bundles. The tip is used as a "pen" a". Next, the ink obtained in Example 5 was filled into the fiber bundle core to a diameter other than 9 mm, and was filled into a marker pen in the same manner as pen a, to obtain "pen b". Similarly, the same pen as pen a was used as "pen c", except that the ink obtained in Example 7 was filled instead of the ink obtained in Example 5, except that the ink obtained in Example 7 was filled instead of the ink obtained in Example 5. The same pen as pen b is called "pen d".

(Test method) (A) Writing test in the oral cavity Use the above-mentioned pens a to d to write on the following parts of the oral cavity of adult men by the following method, and evaluate each performance. (1) Gums: Write a curve about 5cm long from the vicinity of the two upper front teeth to the root of the gums (2) Buccal mucosa: Write three straight lines about 3cm long on the inside of the right cheek (3) Tongue: Write three straight lines about 3cm long in the center of the tongue After writing the above, confirm the writing part. In addition, 5 minutes after writing, the paper was wiped three times with gauze moistened with water to confirm the erasability.

(B) Writing test on skin surface Using the above-mentioned pens a to d, write on the skin surface of the inner left and right wrists of adult women using the following methods, and evaluate each performance. (1) With the writing part in a dry state, write straight lines and numbers about 5cm long (2) With the writing part moistened with water, write straight lines and numbers about 5cm long After writing the above, confirm the writing part. For the right wrist, after 5 minutes of writing, rinse the writing area with running water for 1 minute to confirm discoloration and bleeding. For the left wrist, 5 minutes after writing, wipe it with gauze moistened with water three times to confirm the erasability.

(Test results) (A) Results of the intraoral writing test Each writing part is shown in Figures 1 to 12. Use any stroke in any part of writing and get the following good results. ・Writability and ejection properties: There is no ink ejection failure or clogging at any part, making it difficult to write, and writing can be done without slipping away. ・Fixation: In areas covered by mucous membranes and saliva, the ink can be fixed and remain in the writing area without flowing. ・Color rendering: The writing area can be clearly recognized. ・Water resistance and dryness: No bleeding or blurring caused by saliva occurs, and the writing part can be clearly seen. ・Eraseability: No bleeding or spreading to wipe off the ink, no pigmentation, etc., and no residual traces.

(B) Results of writing test on skin surface Each writing part is shown in Fig. 13 and Fig. 14. In Figure 13, the number "107-12" on the right is written by pen a, the number "107-9" is written by pen b, and the number "109-12" is written by pen b. The person who writes c is the person who writes the straight line "109-9" with pen d. The numbers in Figure 13 are written using corresponding pens. In Figure 14, the straight line written on the left side of the number is the straight line written on the skin in a moist state. When writing with any stroke, the following good results were obtained for writing (1) and (2). ・Writability and ejection properties: Both linear writing and digital writing are not difficult to write due to poor ink ejection or clogging, and you can write without slipping. ・Fixation: Even if it is wet, the ink can be fixed and will not flow, and will continue to stay in the writing area. ・Color rendering: The written part can be clearly recognized. ・Water resistance and dryness: Even if it is exposed to running water, it will not bleed or become blurred, and the written part can be clearly recognized. ・Eraseability: No bleeding or spreading to wipe off the ink, no pigmentation, etc., and no residual traces.

[Performance Evaluation Test Writing on Rats] (Test method) Furthermore, when performing gamma ray irradiation treatment with the above-mentioned pen a under the following conditions that comply with JIS/ISO standards (JIS T 0806-1/ISO 11137-1 and JIS T 0806-2/ISO 11137-2), use the pen a Experimental rats (male SD rats, body weight 292g-346g, "Nihon SLC Co., Ltd.") were used to write on the following parts in the following method, and the writing properties were confirmed and the writing parts were observed over time. ‧γ-ray irradiation treatment: Radioactive nuclide: Co60 Irradiation facility: Nippon Irradiation Services Co., Ltd., inside Tokai Center Irradiation container: box (78×50×150cm) Irradiation device: (Type) JS10000HD, IR-199 (Manufacturing source) MDS Nordion Set target absorbed dose: 50kGy (actual measured value 54.0kGy~67.6 kGy) Irradiation time: 26,000 seconds ・Writing parts: Abdominal skin, skull, thigh muscles, tongue, buccal mucosa ・Writing method: For the abdominal skin, shave the abdominal hair under general anesthesia, and write an ellipse about 1cm wide and 2cm long on the outer skin. In order to confirm the writing position, a blue pigment dispersion ("SA Blue 5636" manufactured by Ogoku Pigment Co., Ltd.) was used to tattoo dots around the writing area. For the skull and thigh muscles, incise each part under general anesthesia. Use a marker pen to write an ellipse about 1cm wide and 2cm long on each part in the same way as the abdominal skin. Dot-like tattoos are performed on the thigh muscles and sutured. The tongue and buccal mucosa are opened under general anesthesia, and circular and dot-shaped tattoos with a diameter of about 5mm are performed. Moreover, as a comparative example, a surgical pen (manufactured by Mizuho Co., Ltd., "Tajima-type marking pen (skin pen)") filled with a 0.2% aqueous solution of succinylcholine chloride (manufactured by Honcho Pharmaceutical Co., Ltd., "HONZO") as ink was used. ", (hereinafter referred to as "pen e")) to write and compare the color rendering properties. ・Observation over time: The written rats were raised at 25° C. for 14 days, and the state of the writing part on the 7th and 14th days was confirmed as follows. Regarding the abdominal skin, after confirming the status of the outer skin on the 7th day, since the ink had disappeared, the outer skin was removed under general anesthesia and the degree of deposition toward the endothelium was confirmed. Aiming at the skull and thigh muscles, each part was incised again under general anesthesia and sutured after visual confirmation. The tongue and buccal mucosa were opened and visually confirmed under general anesthesia.

(Test results) Each writing part is shown in Figures 15 to 20. In addition, in Figure 15, among the two ovals in the figure, the lower part is the writing part using pen a, and the upper part is the writing part using pen e. The points around each are tattoos whose positions are confirmed using the blue pigment dispersion. In addition, in Figure 16, the lower ellipse in the figure is the writing part using pen a, and the upper ellipse is the writing part using pen e. In Figure 17, the left side of the figure shows the thigh muscles written with pen a, and the right side shows the thigh muscles written with pen e. In FIG. 18 , pen a and pen e are used to write on the same parts as in FIG. 15 , but they disappear as shown below. When writing with pen a, the following good results were obtained in writing on any part. ・Writability and ejection properties: There is no difficulty in writing due to poor ink ejection or clogging, and it does not slip open so you can write. ・Fixability: Even when it gets wet with blood, etc., the ink remains fixed and stays on the writing site without flowing. ・Color rendering: The part where the sutra is written can be clearly recognized. The same visual recognition as pen e can be confirmed. (Figure 15, Figure 16, Figure 17) ・Water resistance and dryness: It will not seep out due to blood, body fluids, etc., and will not be blurred. The written part can be clearly recognized. ・Eraseability (confirmed over time): Regarding the abdominal skin, it was confirmed that the outer skin ink disappeared after 7 days (Figure 18), and the endothelium directly under the outer skin was confirmed to be written, but no color deposition was seen (Figure 19 ). Regarding the thigh muscles, it was confirmed that most of the ink disappeared after 14 days (Figure 20). It is impossible to distinguish the tongue and buccal mucosa. For the skull, it was confirmed that some ink remained after 14 days.

[Performance evaluation test: Comparison of physical properties before and after γ-ray irradiation/Time evaluation test] Next, ink was produced again in the same manner as in Example 5 and Example 6, and the average dispersed particle size, viscosity, and pH of the obtained ink were measured as Example 5-2 and Example 6-2, respectively. Subsequently, each ink was placed in a polyethylene container, irradiated with gamma rays under the same equipment and conditions as the writing test on rats, and the viscosity, average dispersed particle size, and pH were measured again. In addition, in order to confirm whether the physical properties have deteriorated during long-term storage, as a time-lapse evaluation test, the ink before and after gamma ray treatment was stored in a constant temperature room at 25°C and 50°C, respectively, and measured for 30 days, 60 days, and 90 days. The average dispersed particle size, viscosity and pH after processing. The results are shown in Table 2. In Table 2, the so-called "change rate" refers to the physical property value before storage (0 days after 0 days) under each condition before irradiation and after irradiation. When it decreases from this value, it is expressed as -%. The relative increase is expressed as +%.

[Time writing test] The ink obtained in Example 5 was subjected to a time-lapse writing test by the following method. First, the ink obtained in Example 5 was filled into the same marking pen used in the above-mentioned (b) writing property test to produce a pen. Make multiple pens and divide them into 6 groups: A, B, C, D, E, F. Place the pens in groups A, B and C into a constant temperature room at 25°C, and the pens in groups D, E and F into a constant temperature room at 50°C. Place each group in the following orientation. ‧Group A and D: Upward (the pen tip is facing upward, and the pen is placed vertically relative to the horizontal plane) ‧Group B and E: facing down (the pen tip faces the ground, and the pen rests vertically relative to the horizontal plane) ‧Group C and F: horizontal (position the pen horizontally) After 30 days, 60 days and 90 days of resting, use each pen to manually write lines on plain paper with a writing distance of 60cm. In each group from A to F, half are written in straight lines and the rest are written in curved lines. In straight writing, write at a speed of 15cm every 10 seconds; in curved writing, write at a speed of 60cm every 10 seconds. Check visually whether the written lines are blurry or light in color. Blurry or light color is more serious than a practical problem and the visibility of the line is reduced is marked as Lines that can be clearly recognized are marked as ○.

Similar to Example 5, a time-lapse writing test was also performed on Examples 8 and 9. Regarding Example 9, confirmation after 90 days of standing was not performed. Each result is shown in Table 3.

From the above examples and comparative examples, as well as the results of the effect confirmation test, it can be seen that the ink of the present invention, which uses a carbon material as a color material and contains a specific water-soluble polymer, has excellent characteristics as a surgical ink.

In addition, based on the performance evaluation test results of the ink obtained in Example 5 using human epidermis and rats, and the state of the writing part shown in Figures 1 to 20, it is shown that even if it is moistened with liquids such as blood, saliva, water, etc. The ink of the present invention can also write well in vivo, and is an excellent surgical ink whose writing part can be clearly recognized. In addition, in the performance evaluation test using rats, it was confirmed that even after gamma ray irradiation treatment, it can exhibit excellent performance as a surgical ink, and it has good performance on the skin epidermis where erasability is required for reasons of appearance. In terms of erasability, it has been confirmed that it exhibits color development and writing properties that are comparable to those of succinylcholine chloride, which has been widely used as surgical ink in the past.

Furthermore, based on the comparison of the physical properties before and after γ-ray irradiation shown in Table 2, it is shown that the ink of the present invention maintains suitable physical properties as a surgical ink even after the γ-ray irradiation treatment. Furthermore, based on the results of the time-lapse evaluation also shown in Table 2, it was confirmed that the ink of Example 5-2 had an average dispersed particle diameter of The viscosity and pH value are both within the aforementioned optimal ranges. In addition, it was also confirmed that the average dispersed particle size, viscosity, and pH after 90 days of storage at 50°C were within the above-mentioned optimal ranges. Regarding the ink of Example 6-2, it was confirmed that regardless of whether it was irradiated with gamma rays or not, the average dispersed particle size, viscosity, and pH after 90 days of storage at 25°C and 50°C were all within the above-mentioned optimum. within the range. Therefore, even when filled in a pen and stored for a long period of time, the ink of the present invention has been shown to be suitably used as a surgical ink.

Furthermore, in the time-lapse writing test of the inks obtained in Examples 5, 8 and 9, even when the ink of the present invention was filled in a pen and stored for a long time, it was shown that the ink can be stored in any orientation at 25°C. Maintain good writing ability. In addition, when the inks of Examples 8 and 9, whose viscosity increased from Example 5, were stored at 50° C. in a face-down state in which the writing properties tended to deteriorate, it was shown that they could maintain practical writing capabilities for a long period of time. sex.

In addition, the evaluation results shown in Table 1 for the inks obtained in Examples 1, 2, 3, 4, 6, 8 and 9 are the same as those in Example 5, and it is considered that the ink has a great influence on the writing properties and fixability of the ink. The affected average dispersed particle size and viscosity value are not significantly different from those in Example 5, and the composition is similar to that in Example 5, including activated carbon and polyvinylpyrrolidone, which are presumed to have a greater contribution to the performance of the ink. Therefore, for the inks obtained in Examples 1, 2, 3, 4, 8 and 9, in the performance evaluation test on human epidermis and rats and the physical property measurement/time evaluation test before and after gamma ray irradiation, the results obtained were the same as those in Example 5 With the same good results as the ink obtained in Example 5-2, it is certainly foreseeable that it will be suitable for surgical use. Similarly, in the performance evaluation test on human epidermis and rats, the ink obtained in Example 6 also obtained the same good results as the ink obtained in Example 5, and it is of course expected to be suitable for surgical use. [Industrial availability]

By the present invention, it is possible to provide an excellent ink that is composed only of ingredients that can be taken into the body, satisfies the required characteristics as a surgical ink, and is suitable for use in writing with a surgical pen, a writing method using the same, and an ink for a surgical marking pen. Manufacturing method. In addition, the ink of the present invention can be used for various purposes such as writing, decorating, and printing on cosmetics, sanitary products, food, toys, daily necessities for infants, and pharmaceuticals.

[Fig. 1] is a diagram showing the gums for writing using the pen a in the embodiment. [Fig. 2] is a diagram showing the gums for writing using the pen b in the embodiment. [Fig. 3] is a diagram showing the gums for writing using the pen c in the embodiment. [Fig. 4] is a diagram showing the gums for writing using the pen d in the embodiment. [Fig. 5] is a diagram showing the buccal mucosa for writing using pen a in the Example. [Fig. 6] is a diagram showing the buccal mucosa for writing using the pen b in the Example. [Fig. 7] is a diagram showing the buccal mucosa for writing using the pen c in the Example. [Fig. 8] A diagram showing the buccal mucosa for writing using the pen d in the Example. [Fig. 9] is a diagram showing the tongue used for writing using the pen a in the embodiment. [Fig. 10] is a diagram showing the tongue used for writing using the pen b in the embodiment. [Fig. 11] is a diagram showing the tongue used for writing using the pen c in the embodiment. [Fig. 12] is a diagram showing the tongue used for writing using the pen d in the embodiment. [Fig. 13] Fig. 13 is a diagram showing skin that was written and dried in the Example. [Fig. 14] A diagram showing skin that was written on and moistened in Example. [Fig. 15] Fig. 15 is a diagram showing the abdominal skin of a rat immediately after writing using pen a and pen e in the Example. [Fig. 16] A diagram showing the skull of a rat just after writing using pen a and pen e in the Example. [Fig. 17] Figure 17 is a diagram showing the thigh muscles of a rat immediately after writing using pen a and pen e in the Example. [Fig. 18] Figure 18 is a diagram showing the abdominal skin of a rat after 7 days of writing using pen a and pen e in the Example. [Fig. 19] Figure 19 is a diagram showing the abdominal endothelium of rats after 7 days of writing using pens a and pen e in Examples. [Fig. 20] Figure 20 is a diagram showing the thigh muscles of the rat that used pen a to write in the Example after 14 days.

Claims (12)

A surgical ink, which is characterized by at least an ink containing a color material, a dispersion medium and a water-soluble polymer with a viscosity average molecular weight of 1,000 to 220,000. The aforementioned color material is a carbon material, and the pH of the ink is 4.0 to 11.0. The aforementioned water-soluble polymer The content is 20 to 200 parts by weight relative to 100 parts by weight of the color material, and the dispersion medium includes more than 50% by weight of water of the liquid constituting the ink. The ink of claim 1, wherein the carbon material is activated carbon. The ink according to any one of claims 1 to 2, wherein the ink contains 5% to 30% by weight of a water-soluble organic solvent. Such as the ink of claim 3, wherein the water-soluble organic solvent includes at least one of ethanol, isopropyl alcohol, polyethylene glycol, propylene glycol and glycerol. The ink according to any one of claims 1 to 4, wherein the average dispersed particle size of the carbon material is 50nm~1μm. For example, the ink according to any one of claims 1 to 5, wherein the ink liquid contains 0.01 to 1.00% by weight of at least one of sodium carbonate and sodium hydroxide. If the ink of any one of the claims 1 to 6 is used, it is an ink for surgical pens. An ink for cosmetics, which is made of the ink according to any one of claims 1 to 7. An edible ink made of the ink of any one of claims 1 to 7. A method for manufacturing the ink according to any one of claims 1 to 9, characterized by adding 0.01 to 1.00% by weight of an alkaline substance based on the total weight of the ink. The manufacturing method of claim 10, wherein the alkaline substance includes at least one of sodium carbonate and sodium hydroxide. The manufacturing method of claim 11, wherein the aforesaid alkaline substance is sodium hydroxide.