JPS62135577A - Water-based pigment ink - Google Patents

Abstract

PURPOSE:To provide the titled ink having excellent long-term dispersion stability, by blending colored powder having colloids deposited within numerous pores formed on the surface of a resin powder with a water-soluble org. solvent and water. CONSTITUTION:Resin powder (e.g., natural fiber) having an average particle diameter of 0.3-100mum is immersed in an etchant (e.g., hydrofluoric acid) to form numerous pores having a pore diameter of 1-10mum on the surface of the powder. Subsequently, the powder is treated with a soln. contg. a reducing agent (e.g., SnCl2) and Ni, Co, Cu, Ag, Au, Pd or the like, thereby depositing the colloid of Ni, Co, Cu, Ag, Au, Pd or the like within the pore. Thus, a colored powder (A) is obtd. The component A is mixed with 1-50wt% water-soluble org. solvent (B) (e.g., ethylene glycol) and 30-80wt% water (C) and, if necessary, a dispersing agent, water-soluble resin, urea (derivative), mildewproofing agent, etc.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a water-based pigment ink, and more specifically, the present invention relates to an aqueous pigment ink that prevents pigment sedimentation, color separation, etc., and thereby significantly improves the long-term dispersion stability of the ink. This invention relates to a new water-based pigment ink.

(Conventional technology and its problems) Water-based pigment inks that use pigments as coloring agents have traditionally had water resistance,
Due to its excellent light resistance, its use has been increasing in recent years9, but on the other hand, it has the disadvantage of being prone to problems such as pigment sedimentation or color separation, so it is particularly difficult to solve this technical problem. A solution is considered important, and various attempts have been made for this purpose.

Specific attempts include: ■Using a dispersant.

That is, a dispersant 9 most suitable for the pigment used, such as various surfactants, water-soluble resins, etc., is used to prevent precipitation and re-agglomeration of the pigment. ■Miniaturization of pigments. That is, by making the pigment as fine as possible, the Brownian motion in the liquid is utilized to prevent the pigment from settling. ■Surface modification of pigments.

That is, the surface of the pigment is made hydrophilic by means such as plasma,
This is an attempt to prevent sedimentation by increasing its affinity with water. ■Graft polymerization to purifiers. That is, the pigment is polymerized with a hydrophilic polymer to increase its affinity with water and prevent its sedimentation. ■Higher viscosity of ink.

That is, by increasing the viscosity of the ink, the movement of the pigment itself is reduced to prevent sedimentation and color separation. etc.

However, the fundamental cause of pigment settling is the difference in specific gravity between the pigment and the dispersion medium, and the fundamental cause of nine-color separation is the difference in specific gravity between the pigments used. The reality is that it has not yet been completely eliminated, and as a result, its effectiveness is weak and it cannot be used as a permanent countermeasure.

(Means to Solve the Problems) As a result of intensive research to solve one or more problems, the present inventor has developed a coloring agent that replaces conventional pigments by forming numerous micropores on the surface of resin powder. It was discovered that the object could be achieved by using a colored powder formed by forming micropores and depositing colloid in the micropores, and finally completed the present invention.

That is, the present invention provides an aqueous pigment comprising at least a colored powder formed by forming countless micropores on the surface of a resin powder and depositing colloid in the micropores, a water-soluble organic solvent, and water. The main theme is ink.

The colored powder used as the colorant in the present invention contains nickel in countless micropores formed on the surface of the resin powder.

It is obtained by depositing colloidal particles such as cobalt by the action of a reducing agent, and therefore, the colored powder is
Since the specific gravity of the resin is approximately 09 to 1.3, which is lower than that of the pigment, it is possible to narrow down the specific gravity difference, which was traditionally thought to be the root cause of the problem, as much as possible. The problem can be solved by preventing sedimentation of the colorant, and by similarly eliminating the difference in specific gravity between the colorants, the problem can be solved.

Two aspects of the present invention will be described in detail below.

The resin powder used is one whose average particle size is adjusted in advance to be approximately constant, and in particular, whose average particle size is 0.3 to 1.
00 μm is preferable from the viewpoint of good dispersibility in a liquid medium. Specific materials include natural fibers,
Natural resin.

Polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybutene, polyamide.

Thermoplastic resins such as polyacrylic acid ester, polyacrylonitrile, polyacetal, ionomer, polyester, and alkyd resins.

Thermosetting resins such as phenol resins, urea resins, melamine resins, xylene resins, silicone resins, and diallyl phthalate resins can be mentioned, and these resins can be used alone or in an appropriate mixture.

This resin powder has countless fine pores formed on its surface, and chemical etching is mainly used to form these fine pores.

i.e. hydrochloric acid, hydrofluoric acid, hydrofluoroboric acid.

Acidic ammonium fluoride, sulfuric acid, phosphoric acid, nitric acid, chromic acid 1
When etching with dichromic acid, permanganate, etc., the above-mentioned resin powder may be immersed with sufficient consideration of its material properties.
Furthermore, a surfactant having high chemical resistance may be added to improve the dispersibility of the resin powder during etching.

The surface of the resin powder thus obtained has pores of 1 mμ in diameter.
Countless fine pores of about 10 μm are formed.

In this way, the resin powder with countless micropores formed on its surface is
Inside the micropores, stannous salts such as stannous chloride, and reducing agents such as tartrate, formaldehyde, formic acid, glycerin, glucose, sodium N,N-diethylglycine, hypophosphite, and borohydride compounds As a result, one or more colloids such as Nikkel, Cobelt, copper, silver, gold, palladium, rhodium, platinum, and lutetium are deposited.

A desired colored powder is obtained. Of course, these colored powders may be used alone or in combination.

Examples of water-soluble organic solvents that are other components in the aqueous pigment ink of the present invention include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, and glycerin; derivatives, monoethanolamine, jetanolamine, ingropanolamine, 2-(2
N-alkanolamines such as -aminoethylamino)ethanol, alcohols such as 2-chloroethanol and tetrahydrofurfuryl alcohol, and acetamide.

Amides such as formamide, N-methylacetamide, N-methylformamide, N-methylpropylamide, N,N-dimethylamide, and the like.

Nitrogen-containing 5-membered ring ketones such as 2-pyrrolidone and N-methyl-2-pyrrolid 7, furthermore, 1-butyrolactone, 7-
Examples include intramolecular esters of ocyancarboxylic acid such as valerolactone, 1-caprolactone, 1-cabrirolactone, and δ-valerolactone. against 1
~50% by weight is preferred.

Water is used as the main solvent, and the amount used is preferably 30 to 80% by weight based on the total amount of the ink.

In the present invention, in addition to the above-mentioned components, there is also a risk that the colorant may become coarse due to aggregation of the colored powders, so in order to prevent this, a dispersant or water-soluble resin is used in combination, and the pen tip is It goes without saying that urea and its derivatives can be used for the purpose of preventing dryness and moisturizing the water, and can also be used in combination with various fungicides, various water-soluble polymer resins as viscosity modifiers, etc.

(Example) The present invention will be explained in more detail below based on two examples.

Example 1 Method for producing colored powder> After washing nylon powder (manufactured by Toshi) with an average particle size of 5 μm with a fluorocarbon solvent, 0.5% of stannous fluoride was added to 20% hydrochloric acid.
The powder was dispersed in a solution containing P/l at room temperature and stirred at high speed for 1 hour to form numerous micropores on the powder surface. Next, this nylon powder was dissolved in a reducing tin salt solution (palladium chloride 0.2 t/1, stannous chloride 10 P/l,
The mixture was placed in a solution of 20 P/l of sodium hydrochloric acid, thoroughly stirred, heated to 60°C, and left to stand for 5 minutes while applying ultrasonic waves. In this way, a black colored powder A was obtained. .

<Ink composition> ・Colored powder A 13 parts by weight ・Diethylene glycol 30 〃・Surfactant: Tukol BT-12゜ (manufactured by Nikko Chemicals ■) 0. By・Polyvinyl alcohol (Hoval PVA 124. Manufactured by Kuraray ■) 2.5 n・
Antifungal agent (Bloxel () XL).

(manufactured by IOI Japan) 0.1 part by weight Kensui 53.6 // Among the above ingredients,
Add the entire amount of polyvinyl alcohol to 20 parts by weight of water, and add 80 parts by weight of polyvinyl alcohol.
The mixture was heated and stirred at °C, and then the remaining water and other ingredients were sequentially added thereto.

After stirring uniformly and centrifuging at 3000 rpm for 30 minutes, black ink with a viscosity of 93 cps was obtained.Example 2 <Method for producing colored powder> Example 1 was applied onto the surface of the same nylon powder as in Example 1. Countless fine pores were formed in the same manner as above, and the nylon powder was then soaked in a reducing tin salt solution (stannous chloride 201/1, 55%).
It was completely dispersed in hydrochloric acid (10 mJ/f), and then washed.

It was added to an alkaline ammonia solution containing 20 P/l of silver nitrate and thoroughly stirred to obtain a yellow colored powder B.

<Ink composition> Sankan color powder B 46 parts by weight
Ethylene glycol 20・Surfactant (Ninocol DLT-1o, manufactured by Nikko Chemicals ■) 0.5 #Bone polybutide (Pebutide P'A-1on, ■manufactured by Nitsupi) 5 〃・Urea
10 - Anti-mold agent (Bloxel GXL.

(manufactured by IOI Japan) 01 〃・Water
4a4〃 The above components were treated in the same manner as in Example 1, and the viscosity was 5.8 cp.
A yellow and colored ink of s was obtained.

Comparative Example 1 Capacity 200m containing 200t transparent iron oxide magnetic balls
1! Place it in a magnetic pot and use 2 parts by weight of this.
The ink composition was the same as in Example 1 except that water was added to 66.6 parts by weight, and a black ink with a viscosity of 90 cps was obtained.

Comparative Example 2 Phthalonanine blue (Sandling Blue BNLF, manufactured by Sandoz Co., Ltd.) ground in an automatic mortar for 2 hours was used as a coloring agent, and the colorant was used in place of 16 parts by weight of colored powder B in Example 2. The ink composition was all the same as in Example 2 except that 53 parts by weight was used and the water was 591 parts by weight.
A blue ink with a viscosity of 6.6 cps was obtained.

(Effect of the invention) Regarding the aqueous pigment inks obtained in Example 1.2 and Comparative Examples 1 and 2, the sedimentation test was carried out (each ink was
Place it in a sedimentation tube with a length of 30 cm.

Leave it for one week at room temperature and visually judge the sedimentation state.

) As a result, in Example 911.2, no sedimentation was observed in both colored powders A and B, but in Comparative Example 1, precipitation of the colorant was clearly observed.

As described above, the water-based pigment ink of the present invention can prevent precipitation or color separation of the colorant as much as possible, and therefore has excellent long-term dispersion stability, and can be used for writing instruments, recorders, printing, stamps, etc. Furthermore, it can be used for various purposes such as cosmetics.

Claims (2)

[Claims] (1) An aqueous pigment ink comprising at least a colored powder made of a resin powder with numerous micropores formed on its surface and a colloid deposited in the micropores, a water-soluble organic solvent, and water. (2) The aqueous pigment ink according to claim (1), wherein the resin powder has an average particle diameter of 0.3 to 100 μm.