JPS6279204A - Production of oligomer-type pigment dispersant - Google Patents

Abstract

PURPOSE:To produce a pigment dispersant exhibiting excellent dispersing power and dispersion stability in water or a water-soluble medium, by reacting an aliphatic alkylamine with an alternating co-oligomer of maleic acid and an alkyl vinyl ether. CONSTITUTION:An alternating co-oligomer of maleic acid and an alkyl vinyl ether (e.g. alternating co-oligomer of methyl vinyl ether and maleic acid) is made to react with an aliphatic alkylamine (e.g. 2-aminoethanol, 3-amino-1- propanol, etc.) to obtain a vinyl oligomer-type pigment dispersant having carboxylic acid hydroxyalkylamide group at the side chain. The amount of the alkylamine is 15pts.wt. per 6pts.wt. of the alternating co-oligomer. USE:Since the dispersant exhibits blue color in alkaline state, it can be used also as a polymeric indicator, special sensor, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for producing a novel water-soluble oligomeric pigment dispersant.

[Prior art]

In recent years, in the paint industry, printing ink industry, and other related coloring material processing industries, oil-based paints and oil-based inks that use large amounts of organic solvents have been replaced with oil-based paints and inks that do not pose a fire risk from a working environment standpoint and are free of solvents. There is a strong demand for a switch to non-polluting water-based paints and water-based emulsion inks that do not scatter into the atmosphere.

However, for this purpose, it is necessary to overcome the technically difficult problem of surface-treating organic or inorganic pigments that are difficult to wet with water to obtain a good aqueous pigment dispersion.

[Purpose of the invention]

In the present invention, an oligomer adsorption layer is formed on the surface of pigment particles via lipophilic alkyl groups, giving a negative charge to the pigment particles, and the surface of the pigment particles is formed at a large number of sites with a long chain of water-soluble oligomers. It is an object of the present invention to provide a method for producing an oligomeric pigment dispersant that can be covered with bonds that are difficult to adhere to.

[Structure of the invention]

The present inventors have already synthesized an oligomer-type pigment dispersant with a large dispersing power that has a pigment structure in the side chain of a long-chain alkyl oligomer (Color Material, Gong, 541 (1984
) '), and as a result of intensive research on the dispersion force and F as eye oil, we discovered that carboxylic acid hydroxyalkylamide substituents, which are effective as dispersing groups in the molecular design of disperse dyes, have been developed into unprecedented industrial applications. The present invention was achieved by successfully introducing this into the side chain of a raw material oligomer using an advantageous method.

Therefore, the present invention is characterized in that an alternating co-low polymer of maleic acid and alkyl vinyl ether is reacted with an aliphatic alkylamine to form a vinyl oligomer having a carboxylic acid hydroquine alkylamide group in the side chain. The gist of this paper is a method for producing oligomeric pigment dispersants.

Hereinafter, the configuration of the present invention will be explained in detail.

In the present invention, an alternating copolymer of maleic acid and alkyl vinyl ether is reacted with an aliphatic alkylamine.

The alternating co-low polymers of maleic acid and alkyl vinyl ether used here are known ones, such as methyl vinyl ether/maleic acid alternating co-low polymers, decyl vinyl ether/male acid alternating co-low polymers, dodecyl vinyl ether・Maleic acid alternating copolymer, etc.

In addition, as the aliphatic alkylamine, general aliphatic alkylamines may be used, but in order to proceed smoothly with the reaction, 2-amine ethanol (2-amine ethanol), which has a high basicity and can also serve as a reaction solvent, is used.
Pka 9.49.25°C, boiling point 171.1°C) is preferably used. As the basic amine, aliphatic alkylamines with longer methylene chains (n) such as 3-amino-1-propanol and mixtures thereof are also effective; There is no problem even if substances with different chemical structures are included.

During the reaction, an alternating copolymer of maleic acid and alkyl vinyl ether (M carboxylic acid)6
What is necessary is to add 15 parts by weight of aliphatic alkylamine to the parts by weight and carry out the reaction at a temperature in the range of 140°C to 170°C for about 0.5 hour. Note that since this reaction is a dehydration reaction, a dehydrating agent can also be used during the reaction.

In this way, a vinyl oligomer having a carboxylic acid hydroxyalkylamide group in its side chain, that is, an oligomer-type pigment dispersant can be obtained. For convenience in use, this vinyl oligomer may be neutralized with caustic soda or an amine to form a basic salt (oligosoap).

The reaction formula in this case is shown below.

(Space below this page) i: e): 00 mouths□ In the above formula, A is an alternating co-low polymer of maleic acid and alkyl vinyl ether, and B is a vinyl oligomer having a carboxylic acid hydroxyalkylamide group in the side chain. represents. Also, R is an alkyl chain, Ro is →CH2-CH2
n and m are integers of 1 or more.

When using this oligomer-type pigment dispersant, the surface tension of an aqueous solution containing 1% by weight of the oligomer-type pigment dispersant, which is a substantial pigment-dispersed aqueous solution, is 50 mN/
It is preferable to prepare an aqueous solution so that it is less than m.

Next, the analytical values of the vinyl oligomer produced by the above reaction are shown in Table 1 below. Table 1 shows samples in which the number of carbon atoms in the alkyl group is 1.12° and 16 (C+, C+z,.

C16). In addition, the infrared absorption spectrum of the sample has characteristic absorptions of amide I and ①, which indicates the presence of an acid amide bond in the product. The oligomer produced is blue to green (λ, 3580-600 nm) on the basic side.

As can be seen from Table 1 above, the produced vinyl oligomer is a carboxylic acid hydroxyethylamide group-containing oligomer in which most of the maleic acid residues in the raw material oligomer are amidated.

Examples are shown below. In addition, in the examples, parts and % are
Parts by weight and weight % are shown, respectively, unless otherwise specified.

Example 1 Methyl vinyl ether/maleic acid alternating low Tli combination 6
15 parts of 2-aminoethanol (molar ratio per structural unit 1:15) was heated to about 80°C to uniformly melt and mix both, and then stirred at 155 to 160°C for about 10 minutes. The reaction was carried out by heating. At this time, the reaction temperature was 170℃
I tried not to exceed.

After the reaction, excess 2-aminoethanol was distilled off under reduced pressure (150° C., 15 Pa), recovered and reused.

Finally, 8 parts of a blue-colored oligomeric pigment dispersant containing a carboxylic acid hydroxyethylamide group was obtained as a product.

Example 2 Instead of the methyl vinyl ether/maleic acid alternating low polymer of Example 1, decyl-
Or dodecyl form was used.

A similar reaction occurred, and a blue to green-blue oligomeric pigment dispersant containing carboxylic acid hydroxyethylamide groups was obtained.

Example 3 Example 1. The oligosoap (sodium salt) obtained in Example 2 has a remarkable ability to lower surface tension, and a 1% aqueous solution has a
．． It showed 0 mN/m (R=-CI&H3?). These are phthalocyanine pigments (α-Cu-Pc),
It showed a great dispersing effect on carbon black and iron oxide (α-Fe 203). The results are shown in Tables 2 and 3 below.

In these tables, the larger the number, the greater the dispersion effect.

For comparison, the dispersion power of Aerosol OT is also shown. In addition, the dispersion force was calculated from the absorbance of the dispersion liquid by the following measuring method (Color Material, Gon, 541 (1984)).

Method for measuring dispersion power: 50 mg of fine pigment powder was collected in a stoppered test tube with a 30 mJ capacity scale, and 20 mj2 of a dispersant aqueous solution was added thereto at 30°C.
After standing for 0 minutes, shake horizontally with a shaker (5 minutes, 4 minutes).
00 times, amplitude 4 cm) and left at 30±1°C for 4 hours. Next, insert the tip of the pentacle up to the 5 ml graduation line from the liquid level in the test tube, gently suck up 2 ml from that area, and transfer it to another test tube.

25ml of water was added to this solution (A), and an integrating sphere haze meter (Nippon Heavy Shiki NDH-20D model, JIS K
-6714), and the dispersion force (%) was determined according to the following formula.

Dispersing force, Dispersing rate (%) =
T-T xo. .

O Here, To: Passage rate of water/8/PL obtained by adding 25 ml of water to 2 pHl of dispersant solution, Ts: Transmittance of (A) above. The larger the number, the greater the dispersion effect. The measurement was repeated two or more times and the average value was taken as the measured value of the dispersion force. The measurement accuracy varies depending on the dispersant, but generally it is about ±3 when the dispersion force is 50% or more, and becomes somewhat larger when it is less than that. After the measurement, the pH value was confirmed.

Here, the expression "dispersion force" refers to the state of the upper layer of the suspension in which no agglomeration, sedimentation, or dispersion of particles occurs after mixing water and pigment and shaking, and is evaluated by keeping the elapsed time after suspension constant. This is what I did. In other words, here the ease of dispersion of particles,
Dispersibility (Dis
This means that a test has been conducted for the persability.

(Margins below this page) Table 3 Dispersion effect of oligosoap aqueous solution on beaker (α-Fe203) Example 4 Pigment paste containing the same oligosoap as used in Example 3 (pigment solid content 20%) 100 10 parts of dextrin was added to the mixture and thoroughly mixed using a high-speed mixer or mill. In addition, 1. Separately prepared water-soluble resin (e.g.
TBAS, Kanto Chemical! A solution of I) was added.

An excellent aqueous pigment dispersion with good compatibility and dispersibility was obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to easily synthesize various oligomeric pigment dispersants and derivatives thereof that exhibit greater dispersion power and dispersion stability in water or an aqueous medium. It becomes possible to create various excellent aqueous pigment dispersion products using this method.

More interestingly, the novel oligomer obtained by the present invention has the property of exhibiting a blue color on the alkaline side, and it is also possible to infer the dispersion and adsorption behavior of the oligomer in water from changes in its light absorption spectrum. , of practical interest.

Furthermore, as mentioned above, this oligomer has a color, so its function can be actively utilized, for example, as a polymer indicator to check for air leaks from changes caused by free amines or acidic carbon dioxide gas. In addition to the original dispersion function, it can be used for special sensors, etc.

Claims (1)

[Claims] Production of an oligomer-type pigment dispersant characterized by reacting an alternating copolymer of maleic acid and alkyl vinyl ether with an aliphatic alkylamine to form a vinyl oligomer having a carboxylic acid hydroxyalkylamide group in the side chain. Law.