JP2016124295A - Ink backflow prevention body composition for writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink backflow prevention body composition having high practicability excellent in visibility and aging stability, which satisfies backflow prevention performance, ink follow-up performance and shock resistance and, further, can suppress addition of ink to an ink storage cylinder inner wall surface.SOLUTION: An ink backflow prevention body composition made of hardly-volatile liquid and a gelation agent which is arranged on a rear end surface of ink directly stored within an ink storage cylinder of a writing instrument and advances in accordance with consumption of the ink is made by containing Nε-lauroyl-L-lysine less than 3 wt.% in the whole amount of the ink backflow prevention body composition.SELECTED DRAWING: None

Description

  The present invention relates to an ink backflow preventive composition for a writing instrument. Furthermore, it is related with the ink backflow prevention body composition for writing instruments arrange | positioned by the end surface of the ink accommodated directly in the ink storage cylinder.

  Conventionally, the ink backflow prevention body composition applied to writing instruments has an ink backflow prevention performance that prevents ink from leaking out from the rear end of the storage cylinder when stored or transported upright (chip upward) or horizontally. , Ink follow-up performance that moves smoothly in the direction of the pen tip as ink decreases during writing, and performance such as impact resistance to prevent ink scattering and ink outflow when the writing instrument falls from a high place is required. .

As the ink backflow preventive composition, the ink backflow prevention is made into a gel-like material by adding a gelling agent such as metal soap or fine particle silica to a hardly volatile organic liquid such as liquid polybutene, α-olefin copolymer and silicone oil. Many body compositions have been proposed and widely used.
Regarding the ink follow-up performance of the ink backflow preventive composition, if the follow-up performance is not sufficient, the ink follow-up will follow while adhering to the inner wall surface of the ink containing cylinder when writing ink, which may impair impact resistance. is there. In addition, the ink adhering to the wall surface may not be removed during ink following, and the visibility (visibility) due to the ink remaining on the wall surface may be deteriorated, or the ink may be used up unclearly.
Therefore, in order to solve the above problems, a composition in which a modified silicone oil is blended with the ink backflow preventive composition has been disclosed (for example, see Patent Documents 1 and 2).

JP-A-11-170757 JP 2000-158876 A

The technique of Patent Document 1 is to add carboxyl-modified silicone to an ink backflow preventer made of silicone oil and a gelling agent, and the technique of Patent Document 2 is to prevent ink backflow made of α-olefin oligomer and fine particle silica. Fluorine-modified silicone oil is added to the body, both of which form a composition in a compatible state and chemically act on the inner wall surface of the ink containing cylinder.
However, in the ink backflow preventive composition, depending on the composition of the ink used, oil separation and separation may occur over time at the ink interface, resulting in lack of product stability, and the aforementioned ink backflow prevention. The performance required for the body composition deteriorated and the practicality was not satisfied.
The present invention satisfies the above-described backflow prevention performance, ink follow-up performance, and impact resistance performance, and can further suppress the ink from adhering to the inner wall surface of the ink containing cylinder, and has excellent visibility and stability over time. A high ink backflow preventive composition is provided.
Furthermore, the present invention provides an ink backflow preventive composition that can satisfy the above-mentioned performance without causing ink leakage due to deformation or collapse even when subjected to a strong impact due to dropping from a high place.

The present invention is an ink backflow preventive composition for a writing instrument, which is disposed on the rear end surface of the ink stored directly in the ink storage cylinder of the writing instrument and comprises a hardly volatile liquid that advances according to the consumption of the ink and a gelling agent. It is a requirement that the total amount of the ink backflow preventive composition contains less than 3% by weight of Nε-lauroyl-L-lysine.
Furthermore, the addition amount of the Nε-lauroyl-L-lysine is less than 1% by weight in the total amount of the ink backflow preventive composition, and the particle size of the Nε-lauroyl-L-lysine is in the ink backflow preventive composition. In the range of 5 μm to 20 μm.
Furthermore, it is a requirement that the hardly volatile liquid is a polybutene having a molecular weight in the range of 520 to 1020.

In the present invention, by adding less than 3% by weight of Nε-lauroyl-L-lysine to a gel-like material obtained by adding a gelling agent to a hardly volatile liquid serving as a base material, ink backflow prevention performance and ink following Performance and impact resistance performance are satisfied, and the composition is excellent in stability so that the ink adhering to the inner wall surface of the ink containing cylinder can be surely removed when following the ink. Therefore, a highly practical ink backflow preventive composition excellent in visible performance and stability over time can be obtained.
In particular, by using polybutene having a molecular weight of 520 to 1020 as a hardly volatile liquid together with Nε-lauroyl-L-lysine, a higher buffering property can be obtained without adjusting the SM value. Even when a strong stress is applied continuously, it is possible to suppress ink leakage due to deformation and breakage, and to suppress the occurrence of ball skipping of the chip that has occurred by adjusting the SM value small. Is possible.

The hardly volatile liquid is used as a base material (base oil) of the ink backflow preventive composition, and includes a non-volatile liquid. Examples of components used include polybutene, α-olefins, liquid paraffin, silicone oil, refined mineral oil, and the like. In particular, polybutene is preferred because it is difficult to mix with ink and is excellent in ink followability and impact resistance.
Specific examples of the commercially available polybutene include Nisseki Polybutene LV-7, LV-50, LV-100, HV-15, HV-35, HV-50, HV-100, and HV. -300, HV-1900, SV-7000 (above, manufactured by JX Nippon Oil & Energy Corporation), Polybutene 015N, 06N, 3N, 5N, 10N, New Glide M (above, NOF ( Etc.)) etc. can be illustrated.
In addition, the said non-volatile liquid can be used in 70-98.9 weight% with respect to the backflow prevention body composition whole quantity.

  The gelling agent is added in order to increase the viscosity of the hardly volatile liquid to a suitable viscosity as the ink backflow preventer composition. Examples of the gelling agent include silica whose surface is hydrophobically treated, fine particle silica whose surface is methylated, aluminum silicate, swellable mica, clay-based thickeners such as bentonite and montmorillonite which are hydrophobically treated, magnesium stearate, Fatty acid metal soaps such as calcium stearate, aluminum stearate, zinc stearate, tribenzylidene sorbitol, fatty acid amide, amide-modified polyethylene wax, hydrogenated castor oil, dextrin compounds such as fatty acid dextrin, cellulose compounds and the like are preferable. The fatty acid aluminum, the fatty acid dextrin, the amide-modified polyethylene wax, and the aliphatic amide that give a sufficient thickening effect to the hardly volatile liquid and are excellent in stability are used.

The Nε-lauroyl-L-lysine is an acylamino acid obtained by condensing L-lysine, which is an amino acid, and lauric acid, which is a higher fatty acid, and is flat white particles having a cleavage property. Since it exists as a solid in a gel-like material obtained by adding a gelling agent to a hardly volatile liquid, an ink backflow preventive composition that is stable for a long period of time without causing oil separation, separation, or curing due to the addition of the fine particles. Can be configured. Moreover, since the ink adhering to the inner wall surface of the ink containing cylinder can be physically scraped off as the ink follows, high visibility can be imparted to the ink backflow prevention body composition.
When the Nε-lauroyl-L-lysine is added in an amount of 3% by weight or more in the total amount of the ink backflow preventive composition, it is necessary to perform a high shear kneading step during production for a long time in order to achieve uniform dispersion. -Lauroyl-L-lysine has a cleavage property, so that the fine particles are cleaved during kneading, and the flakes are crushed. In that case, since it becomes difficult to remove the ink adhering to the inner wall surface of the ink containing cylinder, the visibility cannot be obtained.

  In order to impart visibility to the ink backflow preventive composition without causing the above problems, the amount of Nε-lauroyl-L-lysine needs to be less than 3% by weight, which gives particularly high visibility. Preferably, the addition amount is less than 1% by weight in the total amount of the ink backflow preventer composition (as a specific optimum range, it is added in the range of 0.1 to 0.9% by weight in the total amount of the ink backflow preventer composition). It is necessary to.

Further, in order to effectively obtain the above-mentioned adhesion ink scraping property with a small amount, it is preferable that the particle diameter of Nε-lauroyl-L-lysine is in the range of 5 μm to 20 μm in the ink backflow preventive composition.
The particle diameter is measured by appropriately using a laser diffraction / scattering particle size measuring device, a dynamic light scattering particle size distribution measuring device, a Coulter counter, or the like depending on the particle size range.

  In addition, gelation aids, polar solvents such as alcohol and glycol to improve coloring prevention performance and backflow prevention performance, various surfactants as stabilizers, metal oxide particles and various fine particles can be added as necessary. It is.

  The ink backflow preventive composition is a gelling agent, Nε-lauroyl-L-lysine added to a hardly volatile liquid used as a base oil, and various additives are added as necessary, and dissolved uniformly by heating. It is obtained by uniformly dispersing with a stirrer such as a disper and then kneading with a disperser such as a three roll, kneader or basket mill. Moreover, it can also deaerate by a centrifugal desorption method etc. as needed.

  There is a spread meter (parallel plate viscometer) as a simple means for measuring the hardness and fluidity of a highly viscous liquid such as the ink backflow preventer of the present invention, and the measured value is referred to as the SM value. An ink backflow preventer having a SM value of 20 ° C. in the range of 20 to 60 mm exhibits good characteristics in impact resistance, backflow prevention and ink followability. The SM value range is preferably 20 to 60 mm, more preferably 25 to 50 mm.

When the SM value is adjusted to a small value, the ink backflow prevention body becomes too hard, so that the ball at the pen tip may fly without being able to absorb the strong impact at the time of dropping. This is likely to occur.
Therefore, as a result of studying to solve the above problems, it was found that by using a polybutene having a molecular weight in the range of 520 to 1020 as the hardly volatile liquid, higher buffering properties can be obtained without adjusting the SM value. Improved performance. In addition, the said effect was a peculiar thing acquired at the time of combined use with N (epsilon) -lauroyl-L-lysine.

Polybutene having a molecular weight in the range of 520 to 1020 suppresses deformation by absorbing the stress when a strong stress is applied due to a drop impact. Furthermore, even when a strong stress is repeatedly applied, the initial state can be maintained immediately after dropping or after lapse of time, so that the backflow preventing body composition does not collapse even with repeated drops, and has excellent shape retention. Ink leakage will not occur. In particular, those having a molecular weight in the range of 540 to 1000 are more useful because of their high effects.
Those having a molecular weight of less than 520 are weak in shape retention and easily deformed by strong stress. When the molecular weight is higher than 1020, the buffering property of the backflow preventive composition itself is reduced, causing ball jumping and collapse of the liquid plug after aging. It tends to occur.

  The ink backflow preventive composition is filled with ink in an ink storage cylinder equipped with a nib and then filled at the end, and is used in combination with a solid ink backflow preventive as required. Is done. This prevents the ink from evaporating from the rear end of the ink storage cylinder, and prevents the ink from flowing backward when the pen tip is left facing upward or when an impact is applied.

  As the ink, a conventionally known water-based or oil-based ink is used. When the ink is an oil-based ink, a low-viscosity or medium-viscosity oil-based ink having an ink viscosity at 25 ° C. of from 100 mPa · s to 5000 mPa · s (shear rate of 3.5 [1 / sec]) is preferably used. In the case of water-based ink, a shear-thinning water-based ink is particularly preferably used.

  A marking pen tip or a ballpoint pen tip is used as the pen tip. In particular, application in the form of a ballpoint pen using a ballpoint pen tip is preferable, for example, a chip formed by holding a ball in a ball holding portion in which the vicinity of the tip of a metal pipe is pressed and deformed inward from the outer surface, or A tip that holds a ball in a ball holding portion formed by cutting a metal material with a drill or the like, or a ball that holds a tip formed by cutting a metal pipe or metal material by a spring body The thing biased forward can be applied. Moreover, the said ball | bowl about 0.15-1.2 mm diameters, such as a cemented carbide alloy, stainless steel, a ruby, a ceramic, can be applied.

  As the ink storage cylinder, a metal processed body or a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate or the like is preferably used from the viewpoint of low ink evaporation and productivity. In particular, in the resin molded body, by using a transparent, colored transparent, or translucent molded body, it is possible to visually recognize the ink from the outside, giving a unique design effect, and the ink hue and remaining amount. Can be confirmed. Therefore, the effect of the ink backflow preventive composition of the present invention becomes more remarkable. In addition to directly connecting the chip to the ink storage cylinder, the ink storage cylinder and the chip may be connected via a connecting member. The ink storage cylinder may be a ballpoint pen refill, in which the refill is stored in a shaft cylinder made of resin or metal, or the shaft cylinder is used directly as an ink storage cylinder in the shaft cylinder. You may fill with ink and an ink backflow prevention body.

  Examples and Comparative Examples are shown below, but the present invention is not limited to these Examples. In addition, the number of the Example in a table | surface and a comparative example represents a weight part. The SM value represents a one-minute value of a spread meter at 20 ° C. The particle size was measured using a laser diffraction / scattering particle size distribution measuring apparatus [manufactured by Horiba, Ltd .; LA-300].

The contents of the raw materials in the table will be explained according to the note numbers.
(1) JX Nippon Mining & Energy Co., Ltd., trade name: Nisseki Polybutene HV-35 (average molecular weight: 750)
(2) Product name: Polybutene 3N (average molecular weight: 720), manufactured by NOF Corporation
(3) Product name: Nisseki Polybutene LV-100 (average molecular weight: 500), manufactured by JX Nippon Oil & Energy Corporation
(4) NOF Corporation, trade name: polybutene 015N (average molecular weight: 580)
(5) Shin-Etsu Silicone Co., Ltd., trade name: KF-50-1000
(6) Ethylene bis stearic acid amide, manufactured by NOF Corporation, trade name: Alfro H-50S
(7) Erucic acid amide, manufactured by NOF Corporation, trade name: Alfro P-10
(8) Product name: Aerosil 130, manufactured by Nippon Aerosil Co., Ltd.
(9) Ajinomoto Co., Inc., trade name: Amihope LL (particle size: 10-12 μm)
(10) Momentive Materials Performance Japan product name: Tospearl 1110
(11) Shin-Etsu Silicone Co., Ltd., trade name: X-22-162A

Preparation of Ink Backflow Preventing Body Composition A predetermined amount of gelling agent is added to the base component and stirred at Disper 2000 rpm for 10 minutes, and then the additive component is further added and stirred until it is uniformly dispersed. The ink backflow preventive composition was obtained by centrifugal separation after (3 pass).
The particle diameters of the fine particles (Nε-lauroyl-L-lysine) in the ink backflow preventive composition were 10 to 12 μm in Examples and 2 to 4 μm in Comparative Examples 4 and 5. The measurement of the particle diameter is a value measured by a laser diffraction method using the measuring apparatus, in which the ink backflow prevention composition is dispersed in an appropriate solvent.

Preparation of sample ball-point pen Viscosity at 20 ° C. on a polypropylene pipe (ink containing cylinder) with an inner diameter of 3.8 mm fitted with a stainless steel pipe tip (ball-point pen tip) equipped with a cemented carbide ball with a diameter of 0.5 mm at the tip. Was filled with 0.9 g of water-based red ink (shear thinning pigment ink) of 100 mPa · s, and 0.12 g of the ink backflow preventive compositions of Examples and Comparative Examples were placed in contact with the rear end of the ink, respectively, and then centrifuged. A sample ballpoint pen was obtained by incorporating it into a cap-type writing instrument exterior.

The following tests were carried out using the above sample ballpoint pens, and evaluations were made according to the respective evaluation criteria. The results are shown in Table 2.

Ink follow-up test The sample ball-point pen was tested using a spiral writing tester adjusted to a writing load of 100 g and a writing angle of 70 degrees until the ink disappeared at a writing speed of 4 m / min. Observed.
◯: The ink backflow preventive composition follows well while scraping off the ink deposited on the wall as the ink is consumed, and the visible ink can be secured by eliminating the adhered ink on the wall until writing.
(Triangle | delta): Although an ink backflow prevention body composition tracks, following ink consumption, scraping off wall surface adhesion ink, it cannot remove wall surface adhesion ink until it cuts off.
X: The follow-up property of the ink backflow prevention body composition is poor, and the ink deposited on the wall surface cannot be scraped off or the ink backflow prevention body composition remains attached to the inner wall of the containing cylinder.
Stability test over time After the sample ballpoint pen was left in a 50 ° C. environment with the tip facing upward for 60 days, the state of the ink backflow prevention composition was visually observed.
○: No change is observed in the state of the ink backflow preventer composition.
X: A part of the ink backflow prevention body composition is separated and infiltrated into the ink, or a part of the ink backflow prevention body composition flows out from the rear end of the ink containing cylinder and leaks into the writing instrument exterior. ing.
Drop impact test According to JIS S6037, when the sample ballpoint pen was dropped five times from a height of 1 m with the pen tip upward, the state of the ink backflow preventive composition was visually observed when dropped ten times. Compared with the initial.
A: The ink backflow preventive composition maintains the initial shape and no deformation is observed.
(Triangle | delta): The end surface of the ink backflow prevention body composition is deform | transforming, The whole deform | transforms and collapses.
X: The ink backflow prevention body composition collapse | crumbled and the ink has leaked or the ball is flying from the nib.

Claims (4)

  An ink backflow prevention body composition comprising a hardly volatile liquid and a gelling agent, which is disposed on the rear end surface of the ink stored directly in the ink storage cylinder of the writing instrument and advances in accordance with the consumption of the ink. An ink backflow preventive body composition for a writing instrument, comprising less than 3% by weight of Nε-lauroyl-L-lysine in the total amount of the body composition.   2. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the amount of Nε-lauroyl-L-lysine added is less than 1% by weight based on the total amount of the ink backflow preventive composition.   3. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the particle size of the Nε-lauroyl-L-lysine is in the range of 5 μm to 20 μm in the ink backflow preventive composition.   The ink backflow preventive composition for a writing instrument according to any one of claims 1 to 3, wherein the hardly volatile liquid is a polybutene having a molecular weight in the range of 520 to 1020.