JP5607462B2 - Aqueous ink composition for writing instrument and writing instrument - Google Patents

Description

  The present invention relates to a composition used as an ink for a writing instrument and a writing instrument including the composition.

Ink used in writing instruments such as ballpoint pens, particularly in inks used in so-called water-based gel ballpoint pens, bubbles may occur during use. Once bubbles are generated, they gradually increase with changes in the external environment and the passage of time, preventing the ink from flowing and eventually leaking ink and ink followers from the rear end of the ink storage tube.
In order to prevent this, a defoaming agent for absorbing oxygen in the bubbles may be added to the ink. For example, ascorbic acid may be added to the aqueous ink composition as in the technique described in Patent Document 1 below.

JP-A-3-275778

As in the above prior art, the aqueous ink composition to which ascorbic acid is added has a defoaming action. However, when this is added, since the ascorbic acid itself has high reactivity, it tends to adversely affect the pigment dispersion. That is, the pigment that should be uniformly dispersed in the ink composition aggregates or settles.
In view of the above-described problems, an object of the present invention is to provide stability over time for pigment dispersion in an aqueous ink composition to which ascorbic acids are added as a defoaming agent.

In order to solve the above problems, a writing instrument for aqueous ink composition according to the present invention, pigments, ascorbic acids and HLB is contained 17 or more nonionic surfactants, the nonionic surfactant is the molecular skeleton characterized in that it have a benzene ring in.
That is, by adding a relatively hydrophilic nonionic surfactant having an HLB of 17 or more, the adverse effect on pigment dispersion due to the addition of ascorbic acids is eliminated. When the HLB is 18 or more, the pigment dispersibility is further stabilized, which is preferable. In addition, with a nonionic surfactant having an HLB of less than 17, the temporal stability with respect to pigment dispersion of the ink composition is not good.
The HLB in the present invention is a value determined by the following Griffin equation.
HLB = (molecular weight of hydrophilic group portion / molecular weight of surfactant) × 20

The nonionic surfactant as described above is preferably an ethylene oxide adduct. That is, as the hydrophilic group of the surfactant,
— (CH ₂ CH ₂ 0) _n —H
It is desirable that is added. Here, by adding a large number of ethylene oxide molecules shown in parentheses in the above chemical formula, the hydrophilicity of the surfactant is increased, and the above HLB value can be obtained. Since HLB is defined by the balance between the hydrophobic group and the hydrophilic group, it cannot be generally stated, but the number of moles of the ethylene oxide molecule (that is, the value of “n” in the above chemical formula) is preferably 30 or more. Examples thereof include polycyclic phenyl polyoxyethylene having 50 mol or more of ethylene oxide and polyoxyethylene monostearate having 200 mol or more of ethylene oxide.

Specific examples of the nonionic surfactant as described above include those having a benzene ring in the molecular skeleton, such as polyoxyethylene phenyl ether. More preferably, the number of benzene rings is two or more. Nonionic surfactants having such a molecular structure particularly contribute to the stabilization of pigment dispersion. Examples of such a polycyclic phenyl surfactant include polyoxyethylene polycyclic phenyls to which 50 mol or more of ethylene oxide is added as described above.

  Furthermore, as such a polycyclic phenyl surfactant, polyoxyethylene phenyl ether in which a benzene ring is distyrenated as shown in the following chemical formula (1) can be used.

In the above chemical formula, n is preferably 50 or more.
On the other hand, the nonionic surfactant as described above may have a sterol ring in its molecular skeleton. Of these surfactants, ethylene oxide adducts are still desirable. Specific examples include polyoxyethylene phytosterols to which 30 moles or more of ethylene oxide has been added. Nonionic surfactants having such a molecular structure also contribute to the stabilization of pigment dispersion.

  Ascorbic acids used in the present invention include ascorbic acid and salts thereof such as sodium ascorbate and ascorbic acid derivatives such as sodium phosphate ascorbate, magnesium phosphate ascorbate, glucoside ascorbate, and ascorbic acid-2-phosphate. And -6 palmitic acid. Also included is erythorbic acid, which is a stereoisomer of ascorbic acid, and salts thereof. Among these, ascorbic acid is preferable from the viewpoint of price and effect.

The pigment used in the present invention is not particularly limited, inorganic and organic pigments are conventionally used in conventional aqueous-in click composition, titanium oxide, a resin emulsion can be used a pseudo pigment and colored with a dye or the like. Examples of inorganic pigments include carbon black and metal powder. Examples of the organic pigment include azo lake, insoluble azo pigment, chelate azo pigment, phthalocyanine pigment, perylene and perinone pigment, anthraquinone pigment, quinacridone pigment, dye lake, nitro pigment, nitroso pigment and the like.
More specifically, carbon black, titanium black, zinc white, red pepper, chromium oxide, mica titanium, iron black, cobalt blue, iron oxide yellow, pyridiane, zinc sulfide, lithopone, cadmium yellow, vermilion, cadmium red, yellow lead , Molybdate orange, zinc chromate, strontium chromate, white carbon, clay, talc, ultramarine, precipitated barium sulfate, barite powder, calcium carbonate, lead white, bitumen, manganese violet, aluminum powder, brass powder and other inorganic pigments, C . I. Pigment blue 1, C.I. I. Pigment blue 15, C.I. I. Pigment blue 17, C.I. I. Pigment blue 27, C.I. I. Pigment red 5, C.I. I. Pigment red 22, C.I. I. Pigment red 38, C.I. I. Pigment red 48, C.I. I. Pigment red 49, C.I. I. Pigment red 53, C.I. I. Pigment red 57, C.I. I. Pigment red 81, C.I. I. Pigment red 104, C.I. I. Pigment red 146, C.I. I. Pigment red 245, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 34, C.I. I. Pigment yellow 55, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 166, C.I. I. Pigment yellow 167, C.I. I. Pigment orange 5, C.I. I. Pigment orange 13, C.I. I. Pigment orange 16, C.I. I. Pigment violet 1, C.I. I. Pigment violet 3, C.I. I. Pigment violet 19, C.I. I. Pigment violet 23, C.I. I. Pigment violet 50, C.I. I. Pigment Green 7 and the like are exemplified. Examples of the pseudo pigment obtained by coloring the resin emulsion with a dye include those obtained by coloring a resin made of a copolymer such as acrylonitrile, styrene, or methyl methacrylate with a dye.

In addition to the pigment, a water-soluble dye may be added. As the water-soluble dye, any of direct dyes, acid dyes, food dyes, and basic dyes can be used. More specifically, examples of the direct dye include C.I. I. Direct Black 17, 19, 19, 22, 32, 38, 51, 71, C.I. I. Direct yellow 4, 26, 44, 50, C.I. I. Direct Red 1, 4, 23, 31, 37, 39, 75, 80, 81, 83, 225, 226, 227, C.I. I. Direct Blue 1, 15, 71, 86, 106, 119 and the like. Examples of the acid dye include C.I. I. Acid Black 1, 2, 24, 26, 31, 31, 52, 107, 109, 110, 119, 154, C.I. I. Acid Yellow 7, 17, 19, 23, 25, 29, 38, 42, 49, 61, 72, 78, 110, 141, 127, 135, 142, C.I. I. Acid Red 8, 9, 9, 14, 26, 27, 35, 37, 51, 52, 57, 82, 87, 92, 94, 115, 129, 131, 138, 186, 249, 254, 265, 276, C.I. I. Acid Violet 15, 17 and C.I. I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 40, 41, 43, 62, 78, 83, 90, 93, 103, 112, 113, 158, C.I. I. Acid Green 3, 9, 16, 25, 27 and the like. As food dyes, most of them are included in direct dyes or acid dyes, but examples of those not included in these categories include C.I. I. Food yellow 3 etc. are mentioned. Examples of basic dyes include C.I. I. Basic Yellow 1, 2 and 21, C.I. I. Basic Orange 2, 14, 32, C.I. I. Basic Red 1, 2, 9, 9, 14 C.I. I. Basic Violet 1, 3 and 7, C.I. I. Basic Green 4, C.I. I. Basic Brown 12, C.I. I. Basic Black 2, 8 and the like. These colorants may be used alone or in combination of two or more. The content of these colorants is preferably about 0.5 to 40% by weight relative to the in-click the total composition, is preferably 1 to 30 wt%.

In addition, in the present invention, components necessary for the production of the ink are naturally included in addition to the pigment, the alcohols and the nonionic surfactant having an HLB of 17 or more. It is appropriately selected according to the nature of the.
For example, when the precipitation of the pigment is significant, it is desirable to include a viscosity modifier from the viewpoint of preventing the precipitation. Examples of the viscosity modifier to be used include at least one selected from synthetic polymers, natural gums, celluloses and polysaccharides. Examples of the synthetic polymer include polyacrylic acid and its cross-linked copolymer, polyvinyl alcohol, polyvinyl pyrrolidone and derivatives thereof, polyvinyl methyl ether and derivatives thereof, and natural gums and polysaccharides include, for example, Examples of celluloses such as tragacanth gum, guar gum, locust bean gum, and xanthan gum include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and carboxymethyl cellulose. As the viscosity modifier, “Junron PW-110” manufactured by Toagosei Co., Ltd., “Hibiswako 104” manufactured by Wako Pure Chemical Industries, Ltd., “KELZAN” “KELZAN AR” “K1A96” manufactured by Sanki Co., Ltd., DSP Commercial products such as “Echo Gum GM” manufactured by Gokyo Food & Chemical Co., Ltd. can be suitably used. The content of these viscosity modifiers, relative in-click the total composition is preferably about 0.1 to 1.5 wt%. The content varies depending on the type of the viscosity modifier, and is preferably about 0.1 to 1.5% by weight in the case of a synthetic polymer, and preferably about 0.1 to 0.8% by weight in the case of a natural polysaccharide. If the content of these viscosity modifiers is less than 0.1% by weight, the further effect of containing the viscosity modifier may not be exhibited. It decreases the fluidity of the click, tends to bad writing by tracking poor in-click is likely to occur.

In-click the compositions of the present invention, within the range not impairing the effects of the present invention can be incorporated as needed to further other optional components commonly used in writing instrument in click composition. Examples of other optional components that can be used in the present invention include water-soluble polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, ethylene glycol monomethyl ether (methyl cellosolve), and ethylene glycol monoethyl ether (ethyl cellosolve). ), And other aqueous media such as diethylene glycol monomethyl ether (methyl carbitol), carbitols such as diethylene glycol monoethyl ether (ethyl carbitol), glycol ether esters such as ethylene glycol monoethyl ether acetate; ammonia, Urea, monoethanolamine, diethanolamine, triethanolamine, sodium tripolyphosphate, sodium carbonate and other carbonates and alkali metal salts of phosphoric acid, hydroxylated PH adjusting agents such as alkali metal hydroxides such as thorium; phenol, sodium omadin, sodium pentachlorophenol, 1,2-benzisothiazolin-3-one, 2,3,5,6-tetrachloro-4- (Methylsulfonyl) pyridine, benzoic acid such as sodium benzoate, sorbic acid, alkali metal salt of dehydroacetic acid, antiseptic or antifungal agents such as benzimidazole compounds; benzotriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, tolyl Rust preventive agents such as triazole; lubricants such as phosphate esters, antifoaming agents such as acetylene glycol, and the like can be appropriately selected and used. Moreover, as water used for this invention, purified water, ion-exchange water, etc. are mentioned, The content becomes the remaining quantity (remainder) with respect to the total content of said each component.

Writing instrument for water-based ink composition containing the components as described above, or by filling in the writing instrument of the refill, or by or directly charged to the barrel can be provided in a writing instrument.

Since the present invention is constructed as described above, even if the addition of ascorbic acid in a writing instrument for water-based ink composition as defoaming agent to eliminate the adverse effect on the distribution of ink pigments according ascorbic acids, ink It is possible to ensure the temporal stability of the composition.

(1) Viscosity and average particle diameter measurement conditions Immediately after the ink compositions of Examples and Comparative Examples described below were prepared, the viscosity and average particle diameter were measured by the method described below. The ink composition was placed in a 20 ml glass bottle with a screw cap and stored in an environment at 70 ° C. for 2 weeks, and the viscosity and average particle diameter were measured in the same manner.
The viscosity was measured under the following conditions.
Measuring apparatus: E-type rotational viscometer (VISCOMETER TV-22, manufactured by Toki Sangyo Co., Ltd.).
Measurement conditions: cone 1 ° 34 ′ × R24.
Shear rate: 38.3 / sec.
Measurement time: 60 seconds.
Measurement temperature: 25 ° C.
The average particle size was measured under the following conditions.
Measuring apparatus: Dynamic light scattering particle size distribution measuring apparatus (N4 Plus, manufactured by Beckman Coulter, Inc.).
Measurement conditions: 90 ° scattered light measurement.
Measurement temperature: 25 ° C.

(2) Examples The composition of the ink according to each example of the present invention was as shown in Table 1 below.

As described above, in Examples 1 to 3, Reference Example 4, Example 5 and Reference Example 6, ascorbic acid is added as a defoaming agent. In Example 7, sodium ascorbate is added as a defoaming agent.
The surfactant used in each example is as follows.

(2-1) Example 1
Polyoxyethylene distyrenated phenyl ether was used. The hydrophobic group has two or more benzene rings. The hydrophilic ethylene oxide was 50 mol or more, and the HLB was 18.0.
(2-2) Example 2
Polyoxyethylene polycyclic phenyl was used. The hydrophobic group has two or more benzene rings. The hydrophilic ethylene oxide was 50 mol or more, and the HLB was 17.5.
(2-3) Example 3
Polyoxyethylene phytosterol was used. The hydrophobic group has a sterol ring. The hydrophilic ethylene oxide was 30 mol or more, and the HLB was 18.0.

(2-4) Reference example 4
Polyoxyethylene monostearate was used. The hydrophobic group has a linear structure. The hydrophilic ethylene oxide was 200 mol or more and the HLB was 19.1.
(2-5) Example 5
Polyoxyethylene nonyl phenyl ether was used. The hydrophobic group has one benzene ring. The hydrophilic ethylene oxide was 40 mol or more, and the HLB was 18.0.
(2-6) Reference Example 6
Polyoxyethylene myristyl ether was used. The hydrophobic group has a linear structure. The hydrophilic ethylene oxide was 70 mol or more and the HLB was 18.9.
(2-7) Example 7
The same as in the first embodiment.

(3) Comparative Example The composition of the ink according to each comparative example was as shown in Table 2 below.

As above-mentioned, in Comparative Examples 1-7, ascorbic acid is added as a defoaming agent.
The surfactant used in each comparative example is as follows.

(3-1) Comparative Example 1
No surfactant is used.
(3-2) Comparative Example 2
Polyoxyethylene polycyclic phenyl was used. The hydrophobic group has two or more benzene rings. The hydrophilic ethylene oxide was less than 20 mol and the HLB was 14.3.
(3-3) Comparative Example 3
Polyoxyethylene rosin ester was used. The hydrophobic group has an abietic acid-like tricyclic condensed ring represented by the following chemical formula (2). The hydrophilic ethylene oxide was 30 mol and the HLB was 16.1.

(3-4) Comparative Example 4
Polyoxyethylene sorbitan monolaurate was used. The hydrophobic group has a linear structure. The hydrophilic ethylene oxide was less than 20 mol and the HLB was 16.7.
(3-5) Comparative Example 5
Polyoxyethylene stearylamine was used. The hydrophobic group has a linear structure. The hydrophilic ethylene oxide was less than 20 mol and the HLB was 15.4.
(3-6) Comparative Example 6
Polyoxyethylene hydrogenated castor oil was used. The hydrophobic group has a linear structure. The hydrophilic ethylene oxide was 60 mol and the HLB was 14.0.
(3-7) Comparative Example 7
Sucrose stearate was used. The hydrophobic group has a linear structure. The hydrophilic group did not contain ethylene oxide and the HLB was 16.0.

(4) Measurement results Table 3 below shows the results of the above-described viscosity measurement and average particle diameter measurement using the above-described inks.

First, in Comparative Example 1 in which ascorbic acid was added as a defoaming agent but no surfactant was added, the viscosity itself after 2 weeks at 70 ° C. was not much different from that immediately after adjustment. The particle diameter was found to increase by 88.6% immediately after adjustment. When the surfactant of less than HLB 17 in Comparative Examples 2 to 7 was added to Comparative Example 1, the increase rate of the average particle diameter exceeded 300% of that immediately after the adjustment. Furthermore, in the comparative example 2, the viscosity also increased to 7.7 after the adjustment, and in the comparative examples 3 to 7, since the gelation was complete, it was impossible to measure the viscosity.
On the other hand, in each Example in which a surfactant of HLB 17 or more was added, the viscosity after 2 weeks at 70 ° C. was not much different from that immediately after the adjustment, and the increase rate of the average particle diameter was at most about 20% of that immediately after the adjustment, A marked improvement over Comparative Example 1 was observed.

As described above, when ascorbic acid is added as a defoaming agent, when a surfactant less than HLB 17 is added, the adverse effect is adversely influenced from the viewpoint of an increase in viscosity and an increase in average particle diameter. These were found to improve dramatically when added. This is because the number of moles of ethylene oxide was 50 or more compared to Comparative Example 2 where the HLB was as low as 14.4 because the number of moles of ethylene oxide was less than 20, although it was the same polyoxyethylene polycyclic phenyl. It is clear by comparing the results of Example 2 where the HLB was as high as 17.5.
Of Examples 1 to 3, Reference Example 4, Example 5 and Reference Example 6 to which ascorbic acid is added as a defoaming agent, Example 1 having a ring structure such as a benzene ring or a sterol ring in the hydrophobic group , 2, 3 and the average particle respectively 10.0% rate of increase in the diameter of 5, 15.7%, 15.0% and 17.6%, example 4 and both a hydrophobic group linear structure This is below the rate of increase of 6 (22.6% and 18.1%). From this, it is considered that in the surfactant having an HLB of 17 or more, having a ring structure in the hydrophobic group further contributes to preventing deterioration with time due to ascorbic acid.

  In addition, as in Example 1, the rate of increase in the average particle diameter is slightly higher in Example 7 in which HLB18.0 and three hydrophobic benzene rings are present in Example 7. This is considered to be due to the fact that ascorbic acid was added as a defoaming agent in Example 1 while sodium ascorbate was added in Example 7. Therefore, it seems that ascorbic acid is more suitable as a defoaming agent than sodium ascorbate.

  The present invention can be used for the production of inks used for writing instruments, particularly ballpoint pens, particularly aqueous gel inks.

Claims (7)

A pigment, ascorbic acid, and a nonionic surfactant having HLB of 17 or more ,
It said nonionic surfactant is a writing instrument for water-based ink composition characterized by have a benzene ring in its molecular skeleton. It said nonionic surfactant is a writing instrument for water-based ink composition of claim 1, wherein the ethylene oxide adduct. The benzene ring according to claim 1 or 2 writing instrument for aqueous ink composition, wherein the at least two. The nonionic surfactant according to claim 3 writing instrument for aqueous ink composition, wherein the represented by the following chemical formula (1).
A pigment, ascorbic acid, and a nonionic surfactant having HLB of 17 or more,
The nonionic surfactant brush Symbol instrument for aqueous ink composition you characterized by having a sterol rings in its molecular skeleton.   6. The water-based ink composition for a writing instrument according to claim 5, wherein the nonionic surfactant is an ethylene oxide adduct. Writing instrument comprising the writing instrument for aqueous ink composition according to any one of claims 1 to 6.