JPH07179804A - Direct-filling ink for water-based ball pen and capped ball pen directly filled with the ink - Google Patents

Abstract

PURPOSE:To obtain the subject ink which does not sag and gives an excellent low-temp. writing feeling. CONSTITUTION:This ink comprises 3-10wt.% dye, 10-40wt.% humectant, 0.4-1.0wt.% thixotropic agent comprising a crosslinked acrylic acid polymer, 0.1-0.5wt.% anti-sagging agent comprising at least either a polyethylene/ polyethylene glycol copolymer or a polyester/polyethylene glycol copolymer and having a mol.wt. of 50,000-100,000, and water as the balance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink used for a water-based ballpoint pen. More specifically, the present invention relates to ink directly packed in a barrel and directly supplied to a pen body without using an ink occlusion body or an induction core.

[0002]

2. Description of the Related Art In a conventional water-based ball-point pen, an ink storage medium called batting is used as an ink holding body for an ink having an ink viscosity of 3 to 5 mPas using a pigment as a coloring agent. To supply ink to the pen. For example, JP-A-51-82120, JP-B-54-688, and JP-B-50-375.
No. 71, Japanese Utility Model Laid-Open No. 58-17184, and Japanese Patent Laid-Open No. Sho 5
As described in Japanese Patent Application Laid-Open No. 4-56528, Japanese Patent Application Laid-Open No. 55-146796, Japanese Utility Model Publication No. 3-35585, etc., all of them use an ink occlusion body and an induction core.
This ink supply method has good ink retention properties and does not require precise physical properties as ink, but it has the advantage that suitable ink can be used, but on the other hand, the amount of ink supplied to the pen decreases as the ink decreases during use. However, the handwriting density is not constant, the remaining amount of ink is unknown, and the ink storage amount is small. There are also proposals that do not use an ink occlusion body. For example, Jikkou 61-2
No. 33 publication, No. 61-26077 publication, No. 6 publication
It has been proposed in Japanese Patent Laid-Open No. 23785/1990 to use an ink having a thixotropic property. However, these inks have poor stability with time of the ink, separation and sedimentation of components occur, lack of dry-up resistance, ink clogging occurs, and ink drips from the pen tip during writing. There are problems such as occurrence, and it is not completely satisfactory.

The present inventor has previously described an ink for a water-based ballpoint pen which is directly supplied to the pen body (Japanese Patent Application No. 4-257093).
Invented and filed a patent application. As a result of further research after that, by using polyethylene-polyethylene glycol copolymer as a drooping inhibitor, it is possible to prevent drooping even at low temperature without changing the writability at low temperature. According to the present invention, it was further clarified that, when these copolymers were used, the molecular weight had a great influence on the hanging effect and the writability, and that the polyester-polyethylene glycol copolymer also had a similar action. completed.

[0004]

The present invention has clarified what causes such a problem and how it can be solved, and directly packs without using an ink occlusion body or an induction core. It is possible to increase the storage capacity of the ink, improve the stability of the ink over time, improve the dry-up resistance and the abrasion resistance of the pen body, and have good ink supplyability, spinnability, and tackiness. Ink that does not drip is provided. The ink of the present invention was not affected by moisture in the atmosphere and prevented drooping, and at the same time, prevented line breakage and blurring of writing even at low temperatures.

[0005]

MEANS FOR SOLVING THE PROBLEMS The present invention provides "1. Dye 3 to 10% by weight, moisturizing and wetting agent 10 to 40% by weight, and thixotropic agent 0.4 to 1.0 consisting of a cross-linking acrylic acid polymer. % By weight, molecular weight 50,000-
Anti-sagging agent consisting of 1 or 2 selected from 100,000 polyethylene-polyethylene glycol copolymer and polyester-polyethylene glycol copolymer.
A direct-packing ink for use in a water-based ballpoint pen, which comprises 1 to 0.5% by weight and the balance water. 2. The cross-linked acrylic acid polymer which is a thixotropic agent is a polymer having a molecular weight of 2,000,000 to 6,000,000.
Direct packing ink for use in the water-based ballpoint pen described in item 1. 3. Anti-corrosion lubricant 0.2-2.0 wt% was added, 1
Ink for use in the water-based ballpoint pen according to item 2 or 3. 4. 0.5 to 5.0% by weight of a water resistance additive was added,
An ink for direct packing used in the water-based ballpoint pen according to any one of items 1 to 3. 5. pH adjuster 1.0-6.0 wt% was added, 1
Item 4. An ink for direct packing used for the water-based ballpoint pen according to any one of items 4 to 4. 6. A direct-packing ink for use in the water-based ballpoint pen according to any one of items 1 to 5, to which 1.0 to 2.0% by weight of an antibacterial agent is added. 7. Moisturizing moisturizer is dihydric alcohol, trihydric alcohol,
A direct-packing ink for use in the water-based ballpoint pen according to any one of items 1 to 6, which is one or more selected from derivatives of these alcohols. 8. A direct-packing ink for use in the water-based ballpoint pen according to any one of items 1 to 7, wherein the moisturizing / moisturizing agent is 1 or 2 or more selected from ethylene glycol and polyethylene glycol. 9. Direct-packing ink for use in the water-based ballpoint pen according to any one of items 1 to 8, wherein the rust-preventive lubricant is one or more selected from phosphoric acid ester-based surfactants, benzotriazole, and fatty acid ester. . 10. The water resistance-imparting agent is one or more selected from polyethyleneimine, polyethyleneimine derivatives, polyallylamine, and polyallylamine derivatives, for direct packing for use in the water-based ballpoint pen according to any one of items 1 to 9. ink. 11. The pH adjuster is triethanolamine, 1
Item 13. An ink for direct packing used in the water-based ballpoint pen according to any one of items 1 to 10. 12. A direct-packing ink for use in the water-based ballpoint pen according to any one of items 1 to 11, wherein the metal ion concentration in the ink is 0.45% or less. 13. A cap type ball-point pen in which the ink described in any one of items 1 to 12 is directly packed. Regarding

[0006]

As a result of various studies, the present inventor has found that the problem in the prior art is a serious problem in the thixotropic agent added to the ink in order to make it a direct-packing type. That is, the ordinary thixotropic agent is not suitable for ink. It was also found that there was a problem with the colorant. Since the pigment has no re-dissolution property and the stability of the dispersion over time is not good, the performance as a direct-packing type water-based ballpoint pen ink is inferior to that of a dye. Further, the pigment has a drawback that it exerts an abrasion effect on the ball in the writing portion during writing, which shortens the writing life. There is also the problem of ink dripping.

The first feature of the present invention is to use a crosslinked acrylic acid polymer as a thixotropic agent. The thixotropic property is also called thixotropic, and the whole is gelled to have a high viscosity due to weak hydrogen bonds formed between the component compounds in the aqueous composition, but the hydrogen bonds are broken by stirring or vibration and become liquid. It is a property that becomes. When such performance is used as the ink of the water-based ballpoint pen, the ink becomes highly viscous in a stationary state, that is, in a state where it is not used, and leakage from the pen tip does not occur even if the ink occlusion body is not used. At the time of use, a shearing force is applied by the rotation of the ball of the pen tip, so that the pen has a low viscosity and is supplied to the pen tip. Materials that impart such properties to the aqueous composition include aluminum gum powder, inorganic powder such as bentonite, and natural gums, synthetic gums, and polysaccharides.

However, even if such a composition is blended, sufficient ink performance cannot be obtained. That is, there are problems that the stability of the ink is poor, that tackiness occurs, and that the plastic fluid does not have a clear yield value, which is not preferable as an additive for ink. . However, the cross-linked acrylic acid polymer found by the present inventor is excellent in stability of ink over time, and has an excellent effect of forming the ink as an appropriate plastic fluid and not causing spinnability and tackiness.

The cross-linking acrylic acid polymer used in the present invention is a cross-linking type acrylic acid polymer in which branched acrylic acid polymers are cross-linked with each other at portions other than carboxyl groups to form a network structure. From the experimental results, the molecular weight of 1.7 million or more, preferably 2 million or more is used.
If it exceeds, 000,000, white turbidity occurs during dissolution. Therefore, a polymer having a molecular weight of 2,000,000 to 6,000,000 is suitable.
If the molecular weight is less than 1.7 million, line breaks occur in the handwriting.

Next, the compounding amount of cross-linking acrylic acid will be described. If the viscosity of the ink is not more than 100 mPa · S when the ball of the water-based ballpoint pen is rotated, lineability or blurring occurs and writing performance is poor.
-If it is not more than S, the ink holding property of the ink storage body becomes poor. Further, it is difficult to unconditionally describe the blending amount due to the influence of the molecular weight of the acrylic acid polymer and other compounding agents, but it is necessary to add approximately 0.4 wt% or more in view of the viscosity of the ink. 0.4-1.0% by weight gives favorable results.

A second feature of the invention is the use of dyes as colorants. Since the dye is water-soluble, it improves the stability of the ink. There is no wear effect on the ball of the pen tip, and the pen tip does not clog. The color tone is also good. Since the dye does not affect the thickening mechanism of the crosslinked acrylic acid polymer, a dye having a small absolute number of metal ions contained therein and a dissociation constant smaller than that of the crosslinked acrylic acid polymer exerts a good effect. The concentration of metal ions in the ink is preferably 0.45% or less.

It is considered that the thickening mechanism of the crosslinked acrylic acid polymer is caused by repulsion of COO ⁻ ions of acrylic acid. Therefore, it is preferable to use a dye having a structure in which the number of metal ions represented by Na ⁺ which hinders the repulsion is small and which has a small influence on COO ⁻ ions, in order to impart thixotropic properties to the ink.

The dye used in the present invention is an anionic dye, and an acid dye and a direct dye are particularly preferable. The dye used next is illustrated. Direct Black 19,
Direct Black 154, Direct B
lue 3, Acid Blue 90, Acid R
ed 92, Acid Red 94, Acid Or
an age 56 is used.

A third feature of the present invention is the use of a special anti-sagging agent. In the present invention, a polyethylene / polyethylene glycol copolymer having a molecular weight of 50,000 to 100,000 and a polyester-polyethylene glycol copolymer are used as the sagging inhibitor.
When these copolymers are used, the ink exposed to the air in the pen tip loses its fluidity in cooperation with the cross-linked acrylic acid polymer and acts as a sealant to prevent the ink from dripping from the pen tip. . The amount of the drooling inhibitor to be blended is 0.1 to 0.5% by weight. It is said that such modification of the ink on the pen tip usually has a bad influence on the writability. This is because a pigment is usually used as a colorant, and when such ink modification occurs, writing becomes impossible. Since the present invention uses a dye as a colorant, a new ink is supplied by writing even if the ink loses fluidity at the pen tip, and the dye becomes redissolvable in water and writing is performed. Of. Once the pigment loses its fluidity, it does not re-disperse even if water is supplied, so it does not return to the original ink state, but when a dye is used, it returns to the original ink again.

In the present invention, the use of a polyethylene-polyethylene glycol copolymer or a polyester-polyethylene glycol copolymer having a molecular weight of 50,000 to 100,000 as a sag-preventing agent improves the writability at low temperatures and, in addition, increases the humidity. This is to improve the sagging prevention effect below. The inventors of the present invention have conducted various studies, but none of the polyethylene-polyethylene glycol copolymers and polyester-polyethylene glycol copolymers have a sagging prevention effect. This copolymer may be used alone or in combination.

Even if these two effective copolymers have a molecular weight of 50,000 or less, they absorb moisture in the air,
Does not exert a sealing effect. On the other hand, when it is 100,000 or more, the viscosity of the ink increases like other synthetic resins and natural resins, and line cracks and blurring of writing occur at low temperatures, resulting in poor writing. The molecular weight of these two copolymers is 50,000 to 1
The material of 00000 has little moisture absorption even in a high humidity atmosphere and exhibits a good sealing effect to prevent drooping. Again -2
Even at a low temperature such as 0 ° C., good writing can be performed without causing line cracking or blurring of the writing. A special effect is played.

The fourth feature of the present invention is that one or more selected from polyethyleneimine, polyethyleneimine derivative, polyallylamine and polyallylamine derivative are used as the water resistance-imparting agent. These compounds react with the surface of the paper to give the handwriting strong water resistance. The compounding amount of the water resistance-imparting agent is 0.5 to 5.0% by weight.

When a moisturizing / humidifying agent is added, it is effective in preventing the evaporation of the water content of the ink and preventing the dry-up at the pen tip.
Moisturizers selected from ethylene glycol, propylene glycol, glycerin, diethylene glycol, triethylene glycol, dipropylene glycol, thiodiglycol, polyglycerin, polyethylene glycol, polypropylene glycol, methyl cellosolve, butyl cellosolve, methyl carbitol, ethyl carbitol 1 or 2 or more are used, and the compounding amount is 10 to 40
Weight percent is preferred.

As the rust preventive lubricant, a phosphate ester type surfactant, benzotriazole, a fatty acid ester or the like is used. The pen body of the water-based ballpoint pen is composed of a metal ball and a support, but since the ink is water-based, the ball tends to rust and the rotation of the ball tends to deteriorate. The addition of a rust preventive lubricant is very preferable because it not only prevents rust from occurring but also has the effect of smoothing the rotation of the balls. The compounding amount of the rust preventive lubricant is 0.2 to 2.0% by weight.

In addition, the stability of the ink is improved by adding 1.0 to 6.0% by weight of triethanolamine as a pH adjuster. If necessary, a bacteriostatic agent such as 1.2-benzizothiazol-3 (2H) -one may be added.

[0021]

EXAMPLES Next, the present invention will be specifically described with reference to examples.

Example 1 Direct Black 154 7.5% by weight Cross-linking acrylic acid 0.7% by weight Ethylene glycol 10.0% by weight Sag inhibitor A 0.1% by weight Ph adjuster 2.0% by weight Rust prevention Lubricant 0.6% by weight Antibacterial agent 1.0% by weight Ion exchanger The rest was mixed to prepare an ink. The performance of this ink is shown in Table 1.

[0023]

[Table 1]

(Note) Crosslinking acrylic acid: Hibiswako (Wako Pure Chemical Industries, Ltd.) molecular weight 3 million dripping inhibitor A molecular weight 50000 polyester-polyethylene glycol copolymer dripping inhibitor B molecular weight 100000 polyethylene-polyethylene glycol copolymer Coalescing (Paogen Daiichi Kogyo Seiyaku Co., Ltd.) Dripping inhibitor C Molecular weight 40,000 polyester-polyethylene glycol copolymer Dripping inhibitor D Molecular weight 110000 polyester-polyethylene glycol copolymer ○ Good ◎ Very good △ Slightly × Poor Example 2 to 15 Inks were prepared in the same manner as in the examples except that the composition was as shown in Table 1. Performance is shown in Table 1. Comparative Examples 1 to 15 Inks were prepared in the same manner as in Example 1 except that the composition was shown in Table 2. The performance is shown in Table 1.

[0025]

[Table 2]

[0026]

The ink of the present invention can be directly connected to a writing instrument without using an ink occlusion body or an induction core. It has a large ink storage capacity, good ink stability over time, good dry-up resistance, and good abrasion resistance of the pen body. It has excellent spinnability, tackiness, and drooping-free supply. It is an ink that exhibits good effects.

Claims (13)

[Claims] 1. Dye 3 to 10% by weight, moisturizing and wetting agent 10 to 10.
40% by weight, 0.4 to 1.0% by weight of a thixotropic agent comprising a cross-linked acrylic acid polymer, 1 or 2 selected from a polyethylene-polyethylene glycol copolymer and a polyester-polyethylene glycol copolymer. A direct-packing ink used for an aqueous ball-point pen, which comprises 0.1 to 0.5% by weight of a drooling inhibitor having a molecular weight of 50,000 to 100,000 and the balance water. 2. The direct-packing ink for use in the water-based ballpoint pen according to claim 1, wherein the cross-linked acrylic acid polymer which is a thixotropic agent is a polymer having a molecular weight of 2,000,000 to 6,000,000. 3. A direct-packing ink for use in the water-based ballpoint pen according to claim 1, which further contains 0.2 to 2.0% by weight of a rust preventive lubricant. 4. A direct-packing ink for use in the water-based ballpoint pen according to claim 1, further comprising 0.5 to 5.0% by weight of a water resistance-imparting agent. 5. A direct-packing ink for use in the water-based ballpoint pen according to claim 1, further comprising 1.0 to 6.0% by weight of a pH adjuster. 6. A direct-packing ink for use in the water-based ballpoint pen according to any one of claims 1 to 5, further containing 1.0 to 2.0% by weight of a bacteriostatic agent. 7. The water-based ballpoint pen according to claim 1, wherein the moisturizing humectant is one or more selected from dihydric alcohols, trihydric alcohols and derivatives of these alcohols. Ink for direct packing. 8. The moisturizing humectant is one or more selected from ethylene glycol and polyethylene glycol,
A direct-packing ink for use in the water-based ballpoint pen according to any one of claims 1 to 7. 9. A rust preventive lubricant selected from a phosphate ester type surfactant, benzotriazole and a fatty acid ester.
Alternatively, the direct-packing ink used in the water-based ballpoint pen according to any one of claims 1 to 8, which is 2 or more. 10. The water resistance-imparting agent is polyethyleneimine,
The direct-packing ink for use in the water-based ballpoint pen according to any one of claims 1 to 9, which is one or more selected from a polyethyleneimine derivative, a polyallylamine, and a polyallylamine derivative. 11. A direct-packing ink for use in an aqueous ballpoint pen according to claim 1, wherein the pH adjuster is triethanolamine. 12. The metal ion concentration in the ink is 0.45.
The ink for direct packing used in the water-based ballpoint pen according to any one of claims 1 to 11, which is less than or equal to%. 13. A cap-type ball-point pen that is directly filled with the ink according to claim 1.