Ink capable of improving ink leakage of gel pen and preparation method thereof

Abstract

The invention relates to ink capable of improving ink leakage of a gel pen and a preparation method of the ink, organic resin particles capable of playing a role of a bearing between a ball bead and a ball seat are added into the ink, and in order to improve the existence stability of the organic resin particles, nano cellulose fibers and glucan are added. The organic resin particles, the nano-crystalline cellulose fibers and the glucan can be combined with hydrogen bonds of water under the association effect of the thickening agent to form an aggregate with a three-dimensional network structure, and when the pen point faces downwards in a non-writing state, the aggregate with the three-dimensional network structure can resist the gravity of ink at the pen point, so that ink leakage caused by downward flowing of the ink is avoided; in the writing state, the ball of the gel pen rolls in the ball seat, the shearing force of the ink from the ball is larger than the binding force between the three-dimensional net-shaped structures of the ink, at the moment, the net-shaped structures of the aggregates are damaged, the ink can flow out of the pen point smoothly, and the writing performance of the gel pen is not affected.

Description

TECHNICAL FIELD

[0001] The present application relates to an ink capable of improving the ink leakage of a neutral pen and a preparation method thereof. BACKGROUND

[0002] When a neutral pen is stored with the pen tip pointing downward, ink will remain at the tip of the pen tip, especially for retractable neutral pens without a cap, which often causes the ink to flow down the pen tip. This phenomenon is caused by the gap between the ball of the pen tip and the inner wall of the pen tip and the weight of the ink itself. Such problems bring a lot of trouble to users of neutral pens, such as staining books, staining hands, and even causing ink leakage of neutral pens on exhibition stands at some stationery exhibitions, which seriously affects the honor of neutral pen companies. SUMMARY

[0003] The present application solves the technical problem of the prior art by providing an ink capable of improving the ink leakage of a neutral pen and a preparation method thereof. The ink can overcome its own gravity in a stationary state with the pen tip pointing downward to avoid ink leakage.

[0004] The technical scheme adopted by the present application to solve the above technical problem is as follows:

[0005] An ink capable of improving the ink leakage of a neutral pen, according to the weight components, comprises the following components:

[0006] Water, 30-50 parts;

[0007] Organic pigment, 1-40 parts;

[0008] Alcohol-based solvent, 5-30 parts;

[0009] Thickening agent, 3-8 parts;

[0010] Lubricant, 0.2-5 parts;

[0011] PH adjuster, 1-10 parts;

[0012] Slow-release agent, 0.5-5 parts;

[0013] Preservative, 0.1-1 part;

[0014] Nanocellulose fiber, 4-25 parts;

[0015] Organic resin particles, 2-6 parts;

[0016] Dextran, 1-5 parts;

[0017] The organic resin particles and nanocellulose fiber, dextran are combined with water through the association of the thickening agent and the hydrogen bond, forming an aggregate with a three-dimensional network structure that can resist the gravity of the ink at the pen tip.

[0018] In this invention, during writing, the ball bearing of the gel pen rolls within the ball bearing housing, and the shear force exerted on the ink by the ball bearing is greater than the binding force between the three-dimensional network structures of the ink. During writing, due to the rolling of the ball bearing, the shear force on the ink by the ball bearing is greater than the binding force forming the aggregated network structure. At this point, the aggregated network structure is disrupted, and the ink flows smoothly from the pen tip without affecting the writing performance of the gel pen.

[0019] Preferably, the organic resin particles are organic resin particles with hydrophilic groups, wherein the hydrophilic groups are selected from amino, imino, hydroxyl, and carboxyl groups. This facilitates the interaction between the organic resin particles and the organic pigment particles, allowing the organic pigments to be more uniformly integrated into the three-dimensional network structure.

[0020] Preferably, the organic resin particles have a particle size < 1 μm, the average particle size of the organic resin particles is X μm, and the average particle size of the organic pigment is Y μm, then Y / X < 1. More preferably, Y / X < 0.5. Due to the use of thickener in the ink, the organic resin particles and organic pigment particles interact. When the particle size ratio of the two meets the above conditions, the interwoven structure can fill the gaps in the inner wall of the ball and the ball seat, thus preventing ink leakage at the pen tip.

[0021] Preferably, the average particle size of the nanocellulose fibers is less than 1 μm. The network structure of the nanocellulose fibers plays a major role in enabling the ink to overcome gravity, but if the particle size is too large, it can easily clog the filter element, making ink filtration difficult. Therefore, its average particle size is set to less than 1 μm.

[0022] Preferably, the weight-average molecular weight of the dextran is between 5000 and 12000. For the three-dimensional network structure, the main function of the dextran is to form a thin film in the gaps between the ball and the inner wall of the ball base, which can both keep the ink smooth and prevent ink leakage. If the weight-average molecular weight of the dextran is too low, the film formed will have low hardness and will not be effective in preventing ink leakage at the pen tip. If the weight-average molecular weight of the dextran is too high, the film will be very hard, which will affect the writing performance of the ballpoint pen and cause problems such as smudging. Limiting the weight-average molecular weight of the dextran to between 5000 and 12000 can balance the smooth writing of the ink with the resistance to gravity and the effect of preventing ink leakage.

[0023] Preferably, the alcohol solvent is an ethylene glycol solvent selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and glycerin. Ethylene glycol solvents not only act as dissolving agents but also have hygroscopic properties. When the ink on the pen tip dries, the solidification rate of the film formed by thickeners and other additives is slowed down, thereby improving the anti-drying performance.

[0024] Preferably, the organic pigment exists in the form of a dispersion and is selected from carbon black, aniline black, ultramarine, lead yellow, iron oxide, phthalocyanine, azo, triphenylmethane pigments, violet ketone pigments, pearlescent pigments, fluorescent pigments, and phosphorescent pigments. Alternatively, dyes can be used as coloring agents. Acid dyes, basic dyes, metallized dyes, and various salt-forming dyes can be used. These pigments and dyes can be used alone or in combination of two or more.

[0025] The thickener imparts excellent thixotropic properties to the ink and also stabilizes organic resin particles. The thickener is selected from cross-linked acrylic polymers, xanthan gum, venetan gum, succinyl polysaccharide, etc. These thickeners can be used alone or in combination. The viscosity adjustment range is (800–1300) mPa·s.

[0026] The preservative is used to prevent ink from molding and bacterial growth, extending its lifespan; for example, sodium benzoate. The slow-release agent is used to prevent rust on the metal parts of the pen tip, preventing writing difficulties caused by rust; for example, benzotriazole. The pH adjuster is used to maintain the stability of the ink system; for example, triethanolamine. The humectant is used to maintain the stability of the ink system and improve the ink's intermittent writing performance, while also improving its low-temperature resistance; for example, glycerol.

[0027] The lubricant is used to improve the slipperiness of the water-based ballpoint pen during writing. The lubricant is a type of lubricant used in water-based ink compositions, such as phosphoric acid compounds like the phosphophenol series (PE-510, ML-220, ML-200, RL-310, etc.) from Toho Chemical Industry, the Nikko Chemical NIKKOR series (DDP-2, etc.) from Nikko Chemical, and the Plysurf series (POE alkyl ether phosphates, etc.) from Daiichi Kogyo Pharmaceutical Co., Ltd.

[0028] A method for preparing ink that can improve ink leakage in ballpoint pens includes the following steps:

[0029] At room temperature, add water, humectant, and slow-release agent to a container, turn on the stirrer, stir at 400 r / min for 30 min, the humectant is an alcohol solvent, until completely dissolved;

[0030] Add lubricant, stir at 300 r / min for 10 min, test the pH value, and add alkali (specifically triethanolamine) while stirring to adjust the pH value to 8.3-8.6.

[0031] Add organic resin particles, nanocellulose fibers and dextran in sequence, stir at 400 r / min for 20 min;

[0032] Add some thickener, stir for 40 minutes, test its pH value, and add alkali (specifically triethanolamine) while stirring to adjust the pH value to 8.3-8.6;

[0033] Add preservatives and color paste (specifically, water-based pigment carbon black), adjust the stirring speed to 500 r / min, test its pH value, add alkali (specifically, triethanolamine) while stirring, adjust the pH value to 8.3-8.6, and stir for 60 min;

[0034] Add another portion of thickener and fine-tune the ink to the standard viscosity;

[0035] Stir at 700 rpm for 10 minutes, then add water and stir for another 60 minutes. Filter the ink, degas under negative pressure, and test its physical and chemical properties. If it meets the requirements, discharge and fill the ink to obtain the ink.

[0036] After the ink is assembled into a pen refill, it is centrifuged at 1000 rpm for 60 minutes and -0.8 MPa. After being left at room temperature for 24 hours, the pen refill can be tested for ink leakage.

[0037] In a preferred embodiment of the present invention, the preferred alcohol solvents are glycerol, propylene glycol, and polyethylene glycol 400; the preferred thickener is the hydrophobically modified alkali-swellable thickener Akema; ​​the preferred lubricant is a phosphate ester lubricant purchased from Nikko Chemical; the preferred pH adjuster is triethanolamine; the preferred slow-release agent is benzotriazole; the preferred preservative is 1,2-benzisothiazolin-3-one; the preferred nanocellulose fiber is purchased from Oji Paper; the preferred organic resin particles are purchased from Mitsui Chemicals; and the preferred dextran is purchased from Matsutani Chemicals.

[0038] Compared with the prior art, the advantages of this invention are as follows: This invention adds organic resin particles to the ink, which can act as a bearing between the ball and the ball seat. In order to improve the stability of the organic resin particles, nanocellulose fibers and dextran are added. The organic resin particles, nanocellulose fibers, and dextran can combine with water through hydrogen bonds under the association of thickeners to form an aggregate with a three-dimensional network structure. When the pen tip is pointing downwards in the non-writing state, the aggregate with the three-dimensional network structure can resist the gravity of the ink at the pen tip, thereby preventing the ink from flowing downwards and causing leakage. In the writing state, the ball of the ball pen rolls in the ball seat. The shear force of the ink from the ball is greater than the binding force between the three-dimensional network structure of the ink. At this time, the network structure of the aggregate is destroyed, and the ink flows smoothly from the pen tip without affecting the writing performance of the ball pen. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments.

[0040] Example 1:

[0041] Table 1 shows the formulation components and test data of Examples 1-1 to 1-10 of the present invention.

[0042] Among them, moisturizer A is propylene glycol, moisturizer B is glycerin, and moisturizer C is polyethylene glycol 400.

[0043] The method for preparing ink is as follows:

[0044] At room temperature, add water, humectant (glycerol), and rust inhibitor (i.e., slow-release agent, benzotriazole) to a container, turn on the stirrer, stir at 400 r / min for 30 min, until completely dissolved;

[0045] Add lubricant (PE-510), stir at 300 r / min for 10 min, test the pH value, and add alkali (triethanolamine) while stirring to adjust the pH value to 8.3-8.6.

[0046] Add organic resin particles, nanocellulose fibers and dextran in sequence, stir at 400 r / min for 20 min;

[0047] Add some thickener, stir at 400 r / min for 40 min, test the pH value, and add alkali (triethanolamine) while stirring to adjust the pH value to 8.3-8.6.

[0048] Add preservative (sodium benzoate) and color paste (water-based pigment carbon black), adjust the stirring speed to 500 r / min, test its pH value, add alkali (triethanolamine) while stirring, adjust the pH value to 8.3-8.6, and stir for 60 min;

[0049] During this period, another portion of thickener is added, and the ink is finely adjusted to the target viscosity; the ink is stirred at 700 r / min for 10 min, and finally water is added and stirred for 60 min. The ink is then filtered, degassed under negative pressure, and its physical and chemical properties are tested. If it meets the requirements, it is then discharged and filled to obtain the ink.

[0050] After the ink is assembled into a pen refill, it is centrifuged at 1000 rpm for 60 minutes and -0.8 MPa. After being left at room temperature for 24 hours, the pen refill can be tested for ink leakage.

[0051] The performance of the ink prepared in this embodiment was tested using the following methods:

[0052] Viscosity: The viscosity was tested at 20 degrees Celsius and 1 rotation speed using an E-type viscometer. The unit of viscosity is mpas.

[0053] Line trace: After the pen core has been marked for 600 m by the line marker, check whether there are any phenomena such as broken lines, ink accumulation, or blurring. If there are no such problems, it is judged as qualified. The load setting of the line marker is 100 gf, the writing angle is 65 degrees, and the marking speed is 4 m / min.

[0054] Wear: Place the pen core that has been marked for 600 m on the line marker under a microscope to observe the exposed value of the ball tip of the pen head, and compare it with the initial exposed value to calculate the wear rate. The calculation method of the wear rate is (the initial exposed value of the ball tip of the pen head - the exposed value of the ball tip after marking) / the initial exposed value of the ball tip of the pen head = wear rate. If the wear rate is within 3%, it is qualified.

[0055] Writing effect: The evaluation is divided into 3 levels. The excellent level is for very smooth and fluent writing. Qualified means that one can write smoothly, but the smoothness is not enough. Unqualified means that the writing is heavy, scratches the paper, and is not fluent.

[0056] High-temperature storage: Put the tested pen core and ink into a high-temperature box at the same time. Set the temperature to 50 degrees and the humidity to 60%. After 90 days of heat storage, test the ink leakage, wear, and writing effect of the pen core, and compare with the initial test results. If the change is not significant compared with the initial pen core performance, it can be judged that the high-temperature storage of the pen core is qualified. In the case of ink, mainly examine the stability of the ink viscosity compared with the initial stage. First, check whether there is stratification in the viscosity of the upper and lower layers of the ink. Second, check the rising rate of the ink viscosity. If it exceeds 2 times the initial value, the rising rate of the viscosity is too high. If there is stratification or the rising rate of the viscosity is too high, it will affect the application performance of the ink, and it is judged that the high-temperature storage is unqualified.

[0057] Ink leakage test: Take 50 pen cores and place them in a high-temperature box. Set the temperature to 50 degrees and the humidity to 60%. Hang the pen cores with the pen tips facing downwards and let them stand still for 2 hours. After taking them out, observe the ink leakage situation at the pen tips. If the number of leaking pen cores is 0 - 2, it is qualified; if it is 3 or more, it is unqualified.

[0058] Table 1

[0059]

[0060]

[0061] Example 2:

[0062] Table 2 shows the formula components and test data of Examples 2-1 to 2-5 of the present invention.

[0063] Among them, the moisturizer A is propylene glycol, the moisturizer B is glycerol, and the moisturizer C is polyethylene glycol 400.

[0064] In this example, the preparation method and test method of the ink are the same as those in Example 1.

[0065] Table 2

[0066]

[0067] Example 3:

[0068] Table 3 shows the formulation components and test data of Examples 3-1 to 3-5 of the present invention.

[0069] Among them, moisturizer A is propylene glycol, moisturizer B is glycerin, and moisturizer C is polyethylene glycol 400.

[0070] The preparation and testing methods of the ink in this embodiment are consistent with those in Example 1.

[0071] Table 3

[0072]

[0073]

[0074] Example 4:

[0075] Table 4 shows the formulation components and test data of Examples 4-1 to 4-5 of the present invention.

[0076] Among them, moisturizer A is propylene glycol, moisturizer B is glycerin, and moisturizer C is polyethylene glycol 400.

[0077] The preparation and testing methods of the ink in this embodiment are consistent with those in Example 1.

[0078] Table 4

[0079]

[0080]

[0081] Example 5:

[0082] Table 5 shows the formulation components and test data of Examples 5-1 to 5-5 of the present invention.

[0083] Among them, moisturizer A is propylene glycol, moisturizer B is glycerin, and moisturizer C is polyethylene glycol 400.

[0084] The preparation and testing methods of the ink in this embodiment are consistent with those in Example 1.

[0085] Table 5

[0086]

[0087]

[0088] in conclusion:

[0089] Comparing the formulation composition and test results of Examples 1-5, we can see that:

[0090] By adding organic resin particles, dextran, and nanocellulose fibers, the problem of ink leakage in ballpoint pens can be effectively solved. Specifically, using organic resin particles with a particle size of 0.4μm to 0.8μm provides better ink leakage suppression without affecting the writing feel. Dextran and nanocellulose fibers enhance the ink leakage suppression effect of organic resin particles. Using any one of these components alone is insufficient to suppress ink leakage; all three must work together to achieve the desired effect. Furthermore, organic resin particles larger than 1μm will negatively impact the writing feel.

Claims

1. An ink that can improve ink leakage in ballpoint pens, characterized in that: Based on the weight composition, it includes the following components: water, 30 to 50 parts; Organic pigments, 1-40 parts; Alcohol-based solvents, 5–30 parts; Thickener, 3-8 parts; Lubricant, 0.2 to 5 parts; pH adjuster, 1-10 parts; Sustained-release formulation, 0.5–5 parts; Preservative, 0.1 to 1 part; Nanocellulose fibers, 4 to 25 parts; Organic resin granules, 2 to 6 parts; Glucan, 1 to 5 parts; In this process, the organic resin particles, nanocellulose fibers, and dextran are combined with water through hydrogen bonds under the association of a thickener to form an aggregate with a three-dimensional network structure that can resist the gravity of the ink at the pen tip.

2. The ink for improving ink leakage in ballpoint pens according to claim 1, characterized in that: When writing, the ballpoint pen's roller rolls in the ball seat, and the ink experiences a shear force from the ball that is greater than the binding force between the ink's three-dimensional network structure.

3. The ink for improving ink leakage in ballpoint pens according to claim 1, characterized in that: The organic resin particles are organic resin particles with hydrophilic groups, which are selected from amino, imino, hydroxyl, and carboxyl groups.

4. The ink for improving ink leakage in ballpoint pens according to claim 1, characterized in that: The organic resin particles have a particle size of <1μm, the average particle size of the organic resin particles is Xμm, and the average particle size of the organic pigment is Yμm, then Y / X < 1.

5. The ink for improving ink leakage in ballpoint pens according to claim 4, characterized in that: Y / X < 0.

5.

6. The ink for improving ink leakage in ballpoint pens according to any one of claims 1 to 5, characterized in that: The average particle size of the nanocellulose fibers is less than 1 μm.

7. The ink for improving ink leakage in ballpoint pens according to any one of claims 1 to 5, characterized in that: The weight-average molecular weight of the dextran is between 5,000 and 12,000.

8. The ink for improving ink leakage in ballpoint pens according to any one of claims 1 to 5, characterized in that: The alcohol solvent is an ethylene glycol solvent selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and glycerin.

9. The ink for improving ink leakage in ballpoint pens according to any one of claims 1 to 5, characterized in that: The organic pigment exists in the form of a dispersion and is selected from carbon black, aniline black, ultramarine, lead yellow, iron oxide, phthalocyanine, azo, triphenylmethane pigments, violet ketones, pearlescent pigments, fluorescent pigments, and phosphorescent pigments.

10. A method for preparing an ink that can improve ink leakage in ballpoint pens, characterized in that: The formulation of claim 1 includes the following steps. At room temperature, add water, humectant, and slow-release agent to a container, turn on the stirrer, stir at 400 rpm for 30 minutes until completely dissolved; Add lubricant, stir at 300 r / min for 10 min, test the pH value, and add alkali while stirring until the pH value is adjusted to 8.3-8.6; Add organic resin particles, nanocellulose fibers and dextran in sequence, stir at 400 r / min for 20 min; Add some thickener, stir at 400 r / min for 40 min, test the pH value, and add alkali while stirring to adjust the pH value to 8.3-8.6; Add preservatives and color paste, adjust the stirring speed to 500 r / min, test its pH value, add alkali while stirring, adjust the pH value to 8.3-8.6, and stir for 60 min; Add another portion of thickener and fine-tune the ink to the standard viscosity; stir at 700 r / min for 10 min, then add water and stir for 60 min. Filter the ink, degas under negative pressure, and test the physical and chemical properties of the ink. If it meets the requirements, discharge and fill the ink to obtain the ink.

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