JPH0465111B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a water-based pigment ink, and more particularly to a water-based pigment ink that has excellent handwriting abrasion resistance and water resistance, and good stability over time. (Prior Art) Conventionally, in water-based pigment inks, pigments are dispersed in a solution consisting of a water-soluble polymer, a water-soluble organic solvent, and water using a dispersant. Also known are processed pigments in which the pigment is coated with a water-soluble or poorly water-soluble polymer. An example of the water-soluble polymer is polyvinyl alcohol, and an example of the poorly water-soluble polymer is glue. (Problems to be Solved by the Invention) However, aqueous pigment inks in which pigments are dispersed using the above-mentioned dispersants have a problem in that stability over time is poor and the pigments tend to settle. Water-based pigment inks that use pigments whose surfaces are coated with water-soluble polymers such as polyvinyl alcohol have poor water resistance to handwriting because the water-soluble polymers exist in a dissolved state in the ink, and also have poor pigment sedimentation prevention effects. There were problems in that it was weak and its stability over time was also poor. Water-based pigment inks that use pigments whose surfaces are coated with poorly water-soluble polymers such as glue have excellent abrasion resistance and water resistance of handwriting over time, but if you rub the handwriting with your fingers immediately after it dries, it will cause damage to your hands. I had a problem with it getting dirty. (Means for Solving the Problems) The present inventors have finally completed the present invention as a result of intensive research to solve the above problems. That is, the present invention provides an aqueous pigment comprising a pigment coated with a poly(meth)acrylic ester or a pigment coated with a poly(meth)acrylic ester and a dispersant, a water-soluble polymer, a water-soluble organic solvent, and water. The main theme is ink. Each component of the present invention will be explained in detail below. An example of a specific method for producing a pigment coated with a poly(meth)acrylic ester or a pigment coated with a poly(meth)acrylic ester and a dispersant, which is the gist of the present invention, is shown below. First, there is a pre-mixing process. If necessary, stir and dissolve the most suitable dispersant in water to prepare the poly(meth)acrylic acid ester emulsion to be used.
After adjusting the pH to a stable pH range with sodium hydroxide, etc., add the poly(meth)acrylic acid ester emulsion and pigment one after another with gentle stirring.
Make a premix paste. Next, in the coating process, the premix paste is kneaded in a three-roll mill to destroy the emulsion of poly(meth)acrylic acid ester, and at the same time loosen the pigment into primary particles, making the surface of the pigment a polyester. A processed pigment paste is obtained by coating with (meth)acrylic ester. The pigments mentioned above can be used regardless of whether they are organic pigments or inorganic pigments. Specific examples will be illustrated below. CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 5, CI Pigment Yellow 12,
CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 83, C.
I. Butt Yellow 1, CI Pigment Orange 1,
CI Pigment Orange 5, CI Pigment Orange 13, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 24, C.
I. Butt Orange 3, CI Pigment Red 1,
CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 4, CI Pigment Red 5, CI Pigment Red 7, CI Pigment Red 9, CI Pigment Red 12, CI Pigment Red 22, CI Pigment Red23, CI
Pigment Red 37, CI Pigment Red 38,
CI Pigment Red 48 Calcium Lake, CI
Pigment Red 48 Barium Lake, CI Pigment Red 48 Manganese Lake, CI Pigment Red 49 Barium Lake, CI Pigment Red
50, CI Pigment Red 51, CI Pigment Red 53 Barium Lake, CI Pigment Red 57
Calcium Lake, CI Pigment Red 58 Manganese Lake, CI Pigment Red 60 Barium Lake, CI Pigment Red 63 Calcium Lake, CI Pigment Red 63 Manganese Lake, C.
I. Pigment Red 81, CI Pigment Red 83
Aluminum Lake, CI Pigment Red 88,
CI Pigment Red 112, CI Pigment Red
214, CI Pigment Violet 1, CI Butt Violet 2, CI Pigment Violet 3, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Blue 1,
CI Pigment Blue 2, CI Pigment Blue
15, CI Pigment Blue 16, CI Pigment Blue 17, CI Vat Blue 4, CI Pigment Green 2, CI Pigment Green 7, CI Pigment Green 8, CI Pigment Green 10,
CI Pigment Brown 1, CI Pigment Brown 2, CI Pigment Brown 5, CI Butt Brown 3, CI Pigment Black 1, CI Pigment Black 6, CI Pigment Black 7
There are pigments shown by CI (color index) such as, and these can be used alone or as a mixture of two or more types. The amount used is preferably 3 to 30% by weight based on the total amount of ink. Depending on the type of pigment mentioned above and the type of emulsion of poly(meth)acrylic acid ester, the effect may be sufficient even without the use of a dispersant, but if a dispersant is used, the following nonionic Surfactants and anionic surfactants are used in the pigment coating along with emulsions of poly(meth)acrylic esters. Nonionic surfactants include polyoxyethylene (hereinafter abbreviated as POE) sorbitan monolaurate, POE sorbitan monostearate, etc.
POE alkyl ethers such as POE sorbitan fatty acid ester, POE monooleate, POE oleyl ether, POE cetyl ether, POE tridecyl ether, POE abiethyl ether, POE
-Polyoxypropylene cetyl ether, etc.
POE-polyoxypropylene block copolymer alkyl ether, POE nonylphenyl ether, POE dodecyl phenyl ether, POE dinonylphenyl ether, POE nonylphenyl formaldehyde condensate, styrene maleic acid copolymer Polymer surfactants such as derivatives, POE glycerol borate laurate, etc., and combinations thereof, and anionic surfactants include POE
Sodium nonyl phenyl ether sulfate, di-2
- Sodium ethylhexyl sulfosuccinate, alpha
-Sodium oleinsulfonate, sodium paraffinsulfonate, sodium alkylbenzenesulfonate, sodium naphthalenesulfonate-formalin condensate, sodium alkylnaphthalenesulfonate, special carboxylic acid type polymer activators, etc., and these may be used alone or in combination. It can be used as a mixture of more than one species. Examples of the above-mentioned poly(meth)acrylic ester emulsion include polyacrylic ester emulsion, polymethacrylic ester emulsion, and acrylic copolymer emulsion, and the amount used is based on the total amount of pigment. If the solid content in the emulsion of poly(meth)acrylic ester exceeds 50% by weight, there is a problem that the dispersion stability of the pigment coated with poly(meth)acrylic ester in water-based pigment ink deteriorates over time. If the amount is less than 5% by weight, there is a problem that the effect on the abrasion resistance and water resistance of handwriting is small, so 5 to 50% by weight is preferable. Water-soluble polymers act as anti-sedimentation agents for water-based pigment inks, and are also used to provide pigment fixation and water resistance in handwriting. Specific examples include polyvinyl Alcohol, sodium polyacrylate, polyvinylpyrrolidone, polyethylene oxide, hydroxymethylcellulose, ethylcellulose,
There are cold water soluble starches such as carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxyethyl starch, gum arabic, glue that has been decomposed with enzymes to make it more soluble in water, gelatin, etc., and the amount used is based on the total amount of ink. 0.1-50% by weight is preferred. Examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin, monoethanolamine, diethanolamine, triethanolamine, etc. The amount used is 1 to 25% of the total amount of the water-based pigment ink. Weight percent is preferred. Water is the main solvent and is used in an amount of 40 to 90% by weight based on the total amount of the water-based pigment ink. In addition to the above, urea,
Ureas such as ethylene urea, calcium chloride,
Addition of hygroscopic inorganic compounds such as lithium chloride and magnesium chloride; addition of low-boiling water-soluble organic solvents such as methanol, ethanol, and isopropanol as handwriting drying agents; and other preservatives.
Antifungal agents, surfactants as ink penetrants, foam suppressants, rust preventives when using metal parts, etc. can be freely added. Next, an example of a method for producing the water-based pigment ink will be described. The above-mentioned processed pigment paste is mixed with water-soluble polymer,
A water-based pigment ink is obtained by adding and stirring a mixed solution containing a water-soluble organic solvent, water, and other additives as necessary. In this case, it is preferable to add the pigment paste while stirring the mixed solution with a high-speed stirrer having high shear force, such as a homomixer. Further, if necessary, aggregates of the aqueous pigment ink can be removed using a centrifuge or the like. (Function) Since the aqueous pigment ink of the present invention covers the pigment with poly(meth)acrylic acid ester,
The pigment in the water-based pigment ink behaves as a pigment coated with a water-insoluble polymer, and as a result, the handwriting has excellent abrasion resistance and water resistance, and is unique to the poly(meth)acrylic acid ester mentioned above. Since the dispersion stability improves the dispersibility of the pigment, it is presumed that the stability over time of the aqueous pigment ink becomes better. (Example) The present invention will be explained in more detail with reference to Examples below. In the Examples, "parts" simply means "parts by weight".
shows. Example 1 (Production of processed pigment paste) MA-100 (CI Pigment Black 7) manufactured by Mitsubishi Chemical Industries, Ltd., carbon black) 11.0 parts Nikkor BT-9 (manufactured by Nikko Chemicals Co., Ltd., nonionic surfactant) agent) 0.6 parts Plamile AC-507 (manufactured by Rohm & Haas, USA,
Acrylic emulsion) 5.5 parts water 13.0 parts 25% sodium hydroxide aqueous solution 0.6 parts Add 25% sodium hydroxide aqueous solution and Nikkol BT-9 to water, stir at low speed with a homodisper to dissolve, then MA-100 and Plamile A.C.
-507 was gradually added to the mixture, and the mixture was stirred at low speed until homogeneous for premixing. This was passed through a three-roll mill seven times to obtain a black processed pigment paste. (Preparation of water-based pigment ink) Ethylene glycol 5.0 parts Urea 5.0 parts Sodium dehydroacetate (antifungal agent) 0.5 parts Gelaton BCA-30D (manufactured by Sun Orient Chemical Co., Ltd.,
5.0 parts water 54.5 parts 30.0 parts of the above-mentioned processed pigment paste was added to the aqueous solution in which each component was dissolved according to the above composition, and stirred at high speed with a homodisper for 10 minutes. Adjust the pH to 9.5 with % sodium hydroxide aqueous solution and continue stirring for 1 hour.
I spent time. The black water-based pigment ink obtained above was transferred to a container, tightly stoppered, and allowed to stand for one week, and the precipitate settled at the bottom was removed to obtain the desired black water-based pigment ink. Example 2 The same procedure as in Example 1 was carried out, except that 11.0 parts of MA-100 in Example 1 was replaced with 11.0 parts of Heliofearthread (CI Pigment Red 112) (red pigment, Bayer AG, Germany). A red aqueous pigment ink was obtained. Comparative Example 1 (Production of pigment paste) MA-100 11.0 parts Nikkor BT-9 1.5 parts Water 17.0 parts 25% sodium hydroxide aqueous solution 0.6 parts Add 25% sodium hydroxide aqueous solution and Nikkol BT-9 to water and dissolve with stirring. After that, MA−
100 was slowly added and premixed by stirring at low speed until uniform. This was passed through a three-roll mill seven times to obtain a black pigment paste. (Preparation of water-based pigment ink) A black water-based pigment ink was prepared in the same manner as in Example 1, except that 30.0 parts of the above pigment paste was used in place of 30.0 parts of the processed pigment of Example 1. Comparative Example 2 The same procedure was carried out except that 0.7 parts of Glue HG-132 (manufactured by Nitsupi Co., Ltd., JIS grade glue) was used instead of 5.5 parts of Primal AC-507 in Example 1, and water was changed from 13.0 parts to 18.0 parts. A black aqueous pigment ink was obtained in the same manner as in Example 1. (Effects of the Invention) In order to evaluate each ink obtained in the Examples and Comparative Examples, each ink was filled into a Ceranomatic SRS, a pipe-type writing instrument for drafting manufactured by Pentel Co., Ltd., and the ink was pumped up and down several times. I made it into a writable state and wrote on tracing paper, which is a writing paper for drafting, and used a dropper to apply water to the handwriting after 5 minutes and after leaving it in a constant temperature and humidity room at 50 degrees Celsius and 30% humidity for one month. One minute after dropping it, I checked the dirt on the surface of the paper I had rubbed with my fingers. In addition, in order to evaluate the dispersion stability of each ink over time, 50 ml of each ink was placed in a glass sample bottle, tightly capped, and left in a constant temperature room at 70℃ for 24 hours, then placed in a refrigerator at -5℃ for 24 hours. After the bottle was allowed to cool to room temperature by repeating the cycle test five times, the stopper was removed and the bottom of the bottle was gently scraped with a spatula to check for precipitate. In addition, in all of the inks of Comparative Examples, after the inks were prepared and left at room temperature for 7 days, a considerable amount of sediment was formed at the bottom of the container, and the ink concentration was also thinner than that of the inks of Examples 1 and 2. Ta. Next, the results of the above-mentioned test are shown in Table 1.

[Table] As explained in detail above, the water-based pigment ink of the present invention has excellent abrasion resistance and water resistance for handwriting, and has good stability over time. It can be applied to various types of ink such as printing, printing, and stamping.

Claims (1)

[Claims] 1. An aqueous pigment ink comprising a pigment coated with a poly(meth)acrylic ester or a pigment coated with a poly(meth)acrylic ester and a dispersant, a water-soluble polymer, a water-soluble organic solvent, and water.