Solid writing implement

Abstract

Provided is a solid writing implement containing: a leuco-dye, a long-chain fatty acid ester, and a solvent capable of dissolving or dispersing the leuco-dye.

Description

solid cursive

[0001] The present invention relates to a solid writing material.

[0002] A solid writing material containing a leuco dye, which is an electron-donating dye, is known in which, when written on a paper surface coated with a developer, which is an electron acceptor, the leuco dye contained in the writing develops color, causing the writing to take on a different color tone from that of the solid writing material (see, for example, Patent Document 1, etc.).

[0003] Patent Document 1 discloses an inorganic writing implement containing an electron-donating color-forming dye, a high-boiling point solvent, and polyethylene wax.

[0004] Japanese Patent Application Publication No. 1-72391

[0005] However, the color development of handwriting in the solid writing material of the prior art is insufficient, and there is room for improvement in both the color development of handwriting and the stability over time of the solid writing material.

[0006] An object of the present invention is to provide a solid writing material that can achieve both improved color development of handwriting and improved stability over time of the solid writing material.

[0007] In order to solve the above-mentioned problems, the present invention provides: "1. A solid writing material comprising a leuco dye, a long-chain fatty acid ester, and a solvent capable of dissolving or dispersing the leuco dye. 2. The solid writing material according to item 1, wherein the long-chain fatty acid ester is an ester of a long-chain fatty acid and an alcohol, wherein the long-chain fatty acid has 18 to 40 carbon atoms, and the alcohol has 18 to 40 carbon atoms. 3. The solid writing material according to item 1, wherein the long-chain fatty acid ester is an ester of a long-chain fatty acid and an alcohol, wherein the long-chain fatty acid has 20 to 26 carbon atoms, and the alcohol has 20 to 36 carbon atoms. 4. The solid writing material according to item 1, wherein the long-chain fatty acid ester is myricyl lignocerate, an ester of a long-chain fatty acid and an alcohol, wherein the long-chain fatty acid has 24 carbon atoms and the alcohol has 30 carbon atoms. 5. The solid writing material according to item 1, wherein the content of the long-chain fatty acid ester relative to the total weight of the solid writing material is 5 to 80 mass%. 6. The solid writing material according to item 1, wherein the long-chain fatty acid ester comprises myricyl lignocerate having a long-chain fatty acid with 24 carbon atoms and an alcohol with 30 carbon atoms, and the content of the myricyl lignocerate relative to the total amount of the long-chain fatty acid esters is 30% by mass or more. 7. The solid writing material according to item 1, wherein the long-chain fatty acid ester comprises myricyl lignocerate having a long-chain fatty acid with 24 carbon atoms and an alcohol with 30 carbon atoms, and the content of the myricyl lignocerate relative to the total amount of the long-chain fatty acid esters is 35% by mass or more. 8. The solid writing material according to item 1, wherein the content ratio of the leuco dye to the long-chain fatty acid ester is in the range of 1:2 or more and 1:800 or less by mass.

[0008] The present invention can improve both the color development of handwriting and the stability over time of the solid writing material.

[0009] DETAILED DESCRIPTION OF THE INVENTION In the present specification, the terms "parts", "%", "ratio" and the like indicating the composition are based on mass unless otherwise specified.

[0010] (Solid Writing Material) The solid writing material of this embodiment contains a leuco dye, a long-chain fatty acid ester, and a solvent capable of dissolving or dispersing the leuco dye.

[0011] The solid writing material of this embodiment contains a leuco dye and a long-chain fatty acid ester as an excipient, which allows the solid writing material of this embodiment to achieve both improved color development of handwriting and improved stability over time.

[0012] Furthermore, by using a long-chain fatty acid ester as an excipient, the solid writing material of this embodiment can achieve sufficient strength required for writing and improve heat resistance in addition to the above effects.

[0013] Each component constituting the solid writing material of this embodiment will be described in detail below.

[0014] (Leuco Dye) The leuco dye contained in the solid writing material of this embodiment is not particularly limited as long as it is a dye having electron donating properties and functions as a color former.

[0015] In the solid writing material of this embodiment, known leuco dyes can be used alone or in combination of two or more kinds. In particular, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes are preferably used in the solid writing material of this embodiment.

[0016] Specific examples of leuco dyes include 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3,3-bis(p-dibutylaminophenyl)phthalide, 3-(4-diethylamino-2-ethoxyphenyl)-2-propanol ... 3-[4-(diethylamino)-2-hexyloxyphenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-[4-(diethylamino)-2-hexyloxyphenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7-dimethylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzo fluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylaminofluoran, 2-{3,6-bis(diethylamino)-9-(o-chloroanilino)xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7-(m- trichloromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-di-n-butylamino-7-(o-chloroanilino)fluoran, 3-N-methyl-N,n-amylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-(N,N-diethylamino)-5-methyl-7-(N,N-dibenzylamino)fluoran, benzoyl leucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiropyran, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'- methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide, 3-(N-ethyl-N-tetrahydrofurfuryl)amino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-(2-ethoxypropyl)amino-6-methyl-7-anilinofluoran, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluoran Fluoran, 3-pyrrolidino-7-m-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoromethylanilino)fluoran, 3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluoran, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethyl Amino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3-(N-methyltoluidino)-7-(p-n-butylanilino)fluoran, 3-(N-methyl-N-isopropylamino)-6-methyl-7-anilinofluoran, 3-di-n-butylamino-6-methyl-7-anilinofluoran, 3,6-bis(dimethylamino)fluorenespiro(9,3')-6'-dimethylaminophthalide, 3-(N-benzyl-N-cyclohexylamino)-5,Examples include 6-benzo-7-α-naphthylamino-4'-bromofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-6-methyl-7-mesitidino-4',5'-benzofluoran, 3-N-methyl-N-isopropyl-6-methyl-7-anilinofluoran, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluoran, and 3-diethylamino-6-methyl-7-(2',4'-dimethylanilino)fluoran.

[0017] From the viewpoint of environmental considerations, leuco dyes with higher safety among these are 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentylamino)-6-methyl-7-anilinofluoran, 3-N-di-n-pentylamino-6-methyl-7-anilinofluoran, 3-diethylamino-7-(3-trifluoromethylanilino)fluoran, 3-(N-ethyl-N-4-methylphenylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(3-methylanilino)fluoran, n) Fluoran, 3,3'-bis(dimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-[4-(diethylamino)-2-hexyloxyphenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 2-(N-phenyl-N-methylamino)-6-(N-p-tolyl-N-ethylamino)fluoran, 3,3-bis(1-n-butyl-2-methyl-indol-3-yl)phthalide, 1,3-dimethyl-6-diethylaminofluoran, 3-bromo-3-methyl-6-dibutylaminofluoran, and the like are preferably used.

[0018] The content of the leuco dye contained in the solid writing material of this embodiment is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.3% by mass or more and 3% by mass or less, and even more preferably 0.5% by mass or more and 2% by mass or less, based on the total amount of the solid writing material.

[0019] By including the leuco dye in the above content, the solid writing material of this embodiment has the effect of improving the color development of handwriting.

[0020] (Solvent) The solid writing material of this embodiment contains a solvent capable of dissolving or dispersing the leuco dye.

[0021] The solvent capable of dissolving or dispersing the leuco dye used in the solid writing material of this embodiment is not particularly limited as long as it dissolves or disperses the leuco dye without causing color development and hardly evaporates at room temperature. In consideration of improving the color development of handwriting, a solvent capable of dissolving the leuco dye is preferred.

[0022] Examples of solvents that satisfy the above conditions include at least one selected from high-boiling organic acid esters, fatty acid esters, aromatic hydrocarbons, chlorinated polyphenyls, phosphate esters, etc. Furthermore, as the solvent, it is preferable to use non-toxic organic acid esters such as methyl acetylricinoleate, dibutyl phthalate, butyl phthalyl glycolate, fatty acid esters, and high-boiling aromatic hydrocarbons.

[0023] The fatty acid ester used as the solvent is a fatty acid ester in which the carbon number of the alcohol is not more than 3. Examples of such fatty acid esters include methyl laurate, methyl oleate, isopropyl myristate, and isopropyl palmitate.

[0024] The solvent is a solvent at room temperature and pressure (25°C, 1.013 x 10 ５ Examples of the fatty acid triglycerides include tricapric acid glyceride, tricaprylic acid glyceride, and 2-ethylhexanoic acid triglyceride, which have a fatty acid number of 10 or less and are liquid at room temperature under 2000 kJ / °C (Pa), and terpene oils such as dihydroterpinyl acetate, isobornyl acetate, and 3-methylbutane-1,3-diyne diacetate.

[0025] In order to dissolve the leuco dye well, salicylic acid, benzoic acid ester, benzyl alcohol, or the like may be used as a dissolution aid in combination with the above solvent.

[0026] Specific examples of the solvent include, but are not limited to, fatty acid esters such as Rickcizer C-88 (Ito Oil Mills) and Rickcizer S-4 (Ito Oil Mills).

[0027] The content of the solvent contained in the solid writing material of this embodiment may be an amount that can dissolve or disperse the leuco dye contained in the solid writing material, and may be adjusted appropriately depending on the content of the leuco dye.

[0028] For example, the content of the solvent contained in the solid writing material is preferably 15% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, and particularly preferably 25% by mass or more and 40% by mass or less, based on the total amount of the solid writing material.

[0029] (Long-Chain Fatty Acid Ester) The long-chain fatty acid ester used in the solid writing material of this embodiment is an ester of a long-chain fatty acid and an alcohol.

[0030] Preferably, the long-chain fatty acid has 18 to 40 carbon atoms, and the alcohol has 18 to 40 carbon atoms. Furthermore, it is more preferable that the long-chain fatty acid has 20 to 26 carbon atoms, and the alcohol has 20 to 36 carbon atoms. Furthermore, it is particularly preferable that the long-chain fatty acid has 24 to 26 carbon atoms, and the alcohol has 24 to 32 carbon atoms. Furthermore, it is particularly preferable that the long-chain fatty acid has 24 carbon atoms, and the alcohol has 30 carbon atoms. That is, it is particularly preferable that the long-chain fatty acid ester is myricyl lignocerate.

[0031] When the carbon number of the long-chain fatty acid and the carbon number of the alcohol are within the above ranges, the effect of improving the stability of the core over time can be obtained.

[0032] The content of the long-chain fatty acid ester contained in the solid writing material of this embodiment is preferably 5% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and even more preferably 15% by mass or more and 50% by mass or less, based on the total amount of the solid writing material.

[0033] When the content of the long-chain fatty acid ester contained in the solid writing material is within the above range, the color development of the writing marks and the stability of the core over time are improved.

[0034] When myricyl lignocerate is used as the long-chain fatty acid ester in a solid writing material, the content of myricyl lignocerate relative to the total amount of long-chain fatty acid esters is preferably 30% by mass or more, and particularly preferably 35% by mass or more.

[0035] When the content of myricyl lignocerate contained in the long-chain fatty acid ester is within the above range, the color development of the writing and the stability of the core over time are improved.

[0036] (Other Waxes) The solid writing material of this embodiment may further contain waxes other than long-chain fatty acid esters. For example, the solid writing material of this embodiment may further contain waxes such as polyethylene wax, polypropylene wax, hydrogenated castor oil, 12-hydroxystearic acid, and fatty acid ester wax. Specific examples of hydrogenated castor oil include "Castor Hydrogenated Oil A" manufactured by Ito Oil Mills, Ltd. Examples of fatty acid ester waxes include "WEP-5," "WEP-6," "WEP-8," and "WE-21" manufactured by NOF Corporation.

[0037] (Ratio of leuco dye to long-chain fatty acid ester content) The ratio of the leuco dye to long-chain fatty acid ester content contained in the solid writing material of this embodiment, in terms of mass ratio (leuco dye content:long-chain fatty acid ester content), is preferably in the range of 1:2 or more and 1:800 or less, more preferably in the range of 1:2 or more and 1:200 or less, even more preferably in the range of 1:5 or more and 1:200 or less, and particularly preferably in the range of 1:10 or more and 1:100 or less.

[0038] By ensuring that the ratio of the leuco dye content to the long-chain fatty acid ester content is within the above range, it is possible to effectively achieve both improved color development of the writing and improved stability over time of the solid writing material, as well as realizing sufficient strength required for writing and improved heat resistance.

[0039] (Method for Manufacturing Solid Writing Material) The solid writing material of this embodiment is manufactured by taking a predetermined amount of a solvent and a wax containing a long-chain fatty acid ester and heating the wax to a melting temperature (e.g., 80°C to 100°C) to obtain a solution in which the wax is dissolved. A predetermined amount of a leuco dye is then taken and poured into the wax solution to dissolve the leuco dye. The mixture is then stirred for a predetermined period of time and molded to produce a solid writing material.

[0040] (Applications) The solid writing material of this embodiment is used as a crayon, a cray-pas, or the like.

[0041] When the solid writing material is written on a medium coated with a developer, the leuco dye contained in the solid writing material develops color, and the handwriting develops a color tone different from that of the solid writing material.

[0042] As the color developer, a known substance that acts as an electron acceptor and is capable of causing a leuco dye, which is an electron-donating dye, to develop color when it comes into contact with the leuco dye may be used.

[0043] As the color developer, for example, phenols, organic acids, inorganic acids, or esters or salts thereof can be used.

[0044] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0045] (Examples 1 to 13, Comparative Examples 1 to 5) Solid writing materials of the Examples and comparative solid writing materials of the Comparative Examples were prepared using the materials shown in the Tables as leuco dyes, solvents, and waxes in the amounts shown in the Tables. The content of each material shown in the Tables is expressed as % by mass relative to the total amount of the solid writing material or comparative solid writing material.

[0046] The manufacturing method involved taking the solvent and wax in the amounts shown in the table and heating to the wax melting temperature (e.g., 80°C to 100°C) to obtain a solution in which the wax was dissolved. The leuco dye was then taken in the amount shown in the table and poured into the wax solution to dissolve the leuco dye. After stirring for 30 minutes, the mixture was molded to produce cylindrical solid writing materials and comparative solid writing materials, each 10 mm in diameter and 80 mm in length.

[0047] In the table, TOWAX-3F17 (manufactured by Toa Chemical Industry Co., Ltd.) has a fatty acid with 22 to 24 carbon atoms, and an alcohol with 24 to 34 carbon atoms. TOWAX-3F17 (manufactured by Toa Chemical Industry Co., Ltd.) contains 35 mass% myricyl lignocerate. In the table, Unistar ML2222SL (behenyl behenate) has a fatty acid with 22 carbon atoms, and an alcohol with 22 carbon atoms.

[0048] (Evaluation) The solid writing materials of the examples and the comparative solid writing materials of the comparative examples were evaluated as follows: In the evaluation criteria, "◯" indicates the best evaluation result, "Δ" indicates an intermediate evaluation result between "◯" and "×", and "×" indicates the worst evaluation result.

[0049] (Evaluation of Color of Solid Writing Material) The colors of the solid writing material and the comparative solid writing material were visually observed, and the color of the solid writing material was evaluated according to the following evaluation criteria. The evaluation results are shown in the table below.

[0050] Evaluation criteria for solid writing color: ◯: The color of the leuco dye cannot be confirmed. △: The color of the leuco dye is slightly present. ×: The color of the leuco dye is significantly present.

[0051] (Evaluation of Strength of Solid Writing Material) The strength of the solid writing material and the comparative solid writing material was measured as the bending strength measured using the method specified in "7.5 Bending Strength Test" of JIS S 6026 (crayons and pastels). The measuring machine used was EZ-SX manufactured by Shimadzu Corporation, and the three-point bending strength measurement was carried out immediately after the solid writing material had been stored in an environment of 37°C for one hour or more.

[0052] The standard value for a solid writing material is that it should not break at a diameter of 8 mm or more and up to 4 N. Therefore, if the measurement result of bending strength is 0.78 MPa or more, it is deemed to meet the standard and the evaluation result is "Good", and if it is less than 0.78 MPa, it is deemed to not meet the standard and the evaluation result is "Poor". The evaluation results are shown in the table.

[0053] (Evaluation of heat resistance) After leaving the solid writing material and the comparative solid writing material in a 60°C environment for 1 hour, characters were written on a recording medium (pressure-sensitive recording paper, manufactured by Nippon Paper Industries Co., Ltd., product name: CCP Ace) coated with a developer, and the heat resistance was evaluated according to the following evaluation criteria.

[0054] Evaluation criteria for heat resistance: ◯: Writing possible without problems. △: Softened and difficult to write on. ×: Melted and impossible to write on.

[0055] (Evaluation of Color Development) Using the solid writing material and the comparative solid material, characters were written on a recording medium (pressure-sensitive recording paper, manufactured by Nippon Paper Industries Co., Ltd., trade name: CPP Ace), and the color development of the handwriting was evaluated according to the following evaluation criteria.

[0056] Evaluation criteria for color development: ◯: The color of the leuco dye is clear. Δ: The color of the leuco dye is present but the color development is slightly weak. ×: The color of the leuco dye cannot be confirmed.

[0057] (Evaluation of Color Development Speed) Using the solid writing material and the comparative solid material, characters were written on a recording medium (pressure-sensitive recording paper, manufactured by Nippon Paper Industries Co., Ltd., trade name: CCP Ace), and the color development speed of the handwriting was evaluated according to the following evaluation criteria.

[0058] Evaluation criteria for color development speed: ◯: Color develops within 1 second after writing. Δ: Color takes 1 second or more after writing. ×: Color does not develop.

[0059] (Evaluation of Stability Over Time) The solid writing material and the comparative solid material were stored for three months each at room temperature (25° C.) and at 50° C. Then, for the solid writing material and the comparative solid material in each state before and after storage at room temperature and at 50° C., characters were written on a recording medium (pressure-sensitive recording paper, manufactured by Nippon Paper Industries Co., Ltd., product name: CCP Ace), and the color development of the handwriting was used to evaluate the stability over time according to the following evaluation criteria.

[0060] Evaluation criteria for stability over time: ○: There is almost no change in the color of the handwriting before and after storage. △: The color of the handwriting after storage is lighter than before storage, or it takes more than one second for the color to develop after storage. ×: No color develops after storage.

[0061]

[0062]

[0063]

[0064] As shown in Tables 1 to 3, it was confirmed that the solid writing materials of the Examples were able to achieve both improved color development and improved stability over time compared to the comparative solid writing materials. It was also confirmed that the solid writing materials of the Examples were able to achieve better results in terms of solid writing material color, strength, heat resistance, and color development speed compared to the comparative solid writing materials.

[0065] The solid writing material according to the present invention can be used as a crayon or a cray-pas.

Claims

1. A solid writing implement comprising a leuco dye, a long-chain fatty acid ester, and a solvent capable of dissolving or dispersing the leuco dye.

2. The solid writing implement according to claim 1, wherein the long-chain fatty acid ester is an ester of a long-chain fatty acid and an alcohol, the long-chain fatty acid has 18 or more and 40 or less carbon atoms, and the alcohol has 18 or more and 40 or less carbon atoms.

3. The solid writing implement according to claim 1, wherein the long-chain fatty acid ester is an ester of a long-chain fatty acid and an alcohol, the long-chain fatty acid has 20 or more and 26 or less carbon atoms, and the alcohol has 20 or more and 36 or less carbon atoms.

4. The solid writing implement according to claim 1, wherein the long-chain fatty acid ester is myristyl lignocerate in which the long-chain fatty acid has 24 carbon atoms and the alcohol has 30 carbon atoms.

5. The solid writing implement according to claim 1, wherein the content of the long-chain fatty acid ester relative to the total amount of the solid writing implement is 5% by mass or more and 80% by mass or less.

6. The solid writing implement according to claim 1, wherein the long-chain fatty acid ester contains myristyl lignocerate in which the long-chain fatty acid has 24 carbon atoms and the alcohol has 30 carbon atoms, and the content of myristyl lignocerate relative to the total amount of the long-chain fatty acid ester is 30% by mass or more.

7. The solid writing implement according to claim 1, wherein the long-chain fatty acid ester contains myristyl lignocerate in which the long-chain fatty acid has 24 carbon atoms and the alcohol has 30 carbon atoms, and the content of myristyl lignocerate relative to the total amount of the long-chain fatty acid ester is 35% by mass or more.

8. The solid writing implement according to claim 1, wherein the ratio of the content of the leuco dye to the content of the long-chain fatty acid ester is in the range of 1:2 to 1:800 by mass ratio.

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