JPS5850602B2 - Method for producing aqueous polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aqueous polymeric composition particularly suitable for use as an aqueous printing ink or an aqueous clear coating agent.

Recently, in the field of printing inks and clear coating agents,
In connection with pollution problems, efforts are being made to convert from conventional solvent-based types to water-based types.

Among aqueous types, aqueous solutions have excellent mechanical stability in high-speed printing and alcohol dilutability, but have poor drying properties (blocking resistance) and water resistance.

On the other hand, emulsion type products have excellent drying properties and water resistance, but have poor mechanical stability and alcohol dilutability.

In the end, there was no water-based type that was fully satisfactory in this field.

Here, to explain alcohol dilutability, the reason why alcohol dilutability is necessary in this field is that the addition of alcohol increases drying properties and improves film forming properties.
This is because the photo-selectivity and transferability are improved, and the so-called "swimming" phenomenon can be prevented.

Therefore, in this field, it is a common technical practice to achieve these effects by adding alcohol.

However, in general, emulsions are extremely unstable to the addition of alcohol and usually lack dilutability with alcohol, causing coagulation, gelation, or thickening.

The present invention aims to provide an aqueous polymeric composition which can be used satisfactorily in applications such as aqueous printing inks and aqueous clear coating agents.

That is, as a result of intensive research in view of the above points, the present inventor has
in an aqueous medium using an emulsifier containing an ammonium salt, amine salt, or alkali metal salt of maleic acid mono(polyoxyethylene alkyl ether) ester or maleic acid mono-(polyoxyethylene alkylphenyl ether) ester as a main component. It has been confirmed that an aqueous polymer composition obtained by radical emulsion polymerization of a vinyl monomer containing styrene as a main component satisfies the objects of the present invention very well.

The above emulsifier is a maleic acid half ester obtained by equimolar reaction of polyoxyethylene alkyl ether or polyoxyethylene alkyl phenyl ether, which is commercially available and widely used as a nonionic emulsifier under various trade names, and maleic anhydride. It can be easily obtained by neutralizing with ammonia, amines, caustic alkali, etc.

As can be easily inferred from its structure, it not only has excellent emulsifying power, but it is also characterized by having an unsaturated double bond, particularly a maleic acid structural unit.

This maleic acid structural unit has remarkable copolymerizability with styrene, and styrene is easily graft-polymerized to the emulsifier during radical emulsion polymerization.

As a result, the aqueous polymer composition obtained by emulsion polymerization of the present invention, unlike ordinary emulsion polymers, exhibits properties intermediate between an aqueous solution and an emulsion, and its stability is comparable to that of an aqueous solution.

Furthermore, since alcohol is a poor solvent for styrene polymers, it is believed that the composition of the present invention is stable against the addition of alcohol and exhibits excellent dilutability with alcohol.

If only other vinyl monomers are used without styrene, sufficient alcohol dilutability cannot be obtained.

Furthermore, polystyrene emulsions generally have particularly good drying properties and water resistance.

As a result of the rational combination of these properties, the polymer composition of the present invention has excellent properties such as mechanical stability, alcohol dilutability, drying properties, and water resistance, and can be used in water-based inks and water-based inks. It can be inferred that satisfactory results can be obtained when used in applications such as clear coating agents.

Note that the emulsion polymerization may be carried out according to a known ordinary emulsion polymerization technique.

In the present invention, there is no problem in using other nonionic, anionic, or nonionic/anionic amphoteric emulsifiers in addition to the emulsifiers described above.

In addition to styrene, other vinyl monomers copolymerizable with styrene may be used in combination as the vinyl monomer.

However, as the main component of the emulsifier, ammonium salt, amine salt or alkali metal salt of maleic acid mono-(polyoxyethylene alkyl ether) ester or maleic acid mono-(polyoxyethylene alkylphenyl ether) ester must be used. The polymer composition of the present invention can satisfy the object of the present invention only by using styrene as the main monomer component and the combination of the two as an essential requirement. This was first revealed by someone.

Specific examples are shown below, but they do not limit the scope of the present invention.

Reference Example 1 (Production method of emulsifier of the present invention) Polyoxyethylene oleyl ether (number of moles of ethylene oxide added: 14) 176.1' (0.2 mol), maleic anhydride 19.1' (0.2 mol) 500Tl1
1) Charge the mixture into a fourth flask and react at 95°C for 2 hours.

The reactant is a brown, transparent, viscous liquid with an acid value of 58.2 (half ester theoretical acid value of 571).

Reference Example 2 (Production of emulsifier of the present invention) (a) Polyoxyethylene oleyl ether (number of moles of ethylene oxide added: 9) Molecular weight: 664 (b) Polyoxyethylene nonyl phenyl ether (number of moles of ethylene oxide added: 28) / Molecular weight: 1452 ←→Polyoxyethylene nonylphenyl ether (number of moles of ethylene oxide added: 12) Molecular weight 748 Each of the above nonionic surfactants (A), (Ex), and (-) was reacted with maleic anhydride in equimolar amounts as in Reference Example 1. Three types of emulsifiers used in the present invention were obtained.

The respective acid values were as follows.

Nonionic interface used (half ester theoretical activator
Acid value Acid value) (a) 74,5
73.6 (mouth) 37.1
36.2←→ 67,0
66, 3 Example 1 7 g of the equimolar reaction product of polyoxyethylene oleyl ether prepared in Reference Example 1 (number of moles of ethylene oxide added: 14) and maleic anhydride, 100 f of water in a stirrer, a water-cooled condenser, a thermometer, nitrogen 5 equipped with a gas introduction pipe
001rll in a four-loop flask and dissolve.

Add a small amount of 10% aqueous ammonia to adjust the pH to 6.5.

Add 70 g of styrene, introduce nitrogen gas, and emulsify.

Ammonium persulfate 0. Add aqueous solution 31 containing IP,
Next, 3 tons of an aqueous solution containing 0.11 sodium bisulfite? Add.

Thereafter, polymerization is carried out at 40 to 70°C for 8 hours. Midway catalyst addition 4
After an hour, 31 ml of an aqueous solution containing 0.1 ammonium persulfate is added.

A stable emulsion composition (11187f) with a nonvolatile content of 40.8% and an apparently very small particle size was obtained.

Example 2 In place of styrene 70P in Example 1, styrene 561 and methyl methacrylate 14'? A stable emulsion composition (2) 187r having a non-volatile content of 41.0% and having a very small particle size in appearance was obtained by performing the same operation using .

Comparative Example 1 Polyoxyethylene oleyl ether (number of moles of ethylene oxide added: 14) in place of the emulsifier in Example 1
When the same operation was performed using 6.3P and 0.7z maleic anhydride, a large amount of aggregates were produced and a stable emulsion could not be obtained.

Example 3 In place of the emulsifier in Example 1, Example 2 was carried out using equimolar reaction product 71 of polyoxyethylene nonylphenyl ether (number of moles of ethylene oxide added: 12) of Reference Example 2-←→ and maleic anhydride. Proceed as in step 1 and reduce the non-volatile content to 4.
A stable emulsion composition (3) 1871 with a particle size of 1.0% and an apparently very small particle size was obtained.

Example 4 In place of the emulsifier in Example 1, equimolar reaction product 7 of polyoxyethylene oleyl ether (number of moles of ethylene oxide added: 9) of Reference Example 2-(a) and maleic anhydride was used.
The same procedure as in Example 1 was carried out except that the non-volatile content was 40.
9%, good appearance, stable emulsion composition (4) 18
I got 8f.

Example 5 In place of the emulsifier in Example 1, an equimolar reaction product 7z of polyoxyethylene nonylphenyl ether (additional moles of ethylene oxide: 28) of Reference Example 2-(b) and maleic anhydride was used. The procedure was carried out in the same manner as in Example 1 to obtain 187 g of a stable emulsion composition (5) with a non-volatile content of 41.0% and an apparently small particle size.

Test Examples Compositions of Examples 1 to 5 above and Control Examples (1) to (3) below
) were tested.

Control example (1) Polyoxyethylene alkyl ether sulfonate emulsifier 7'? A styrenic emulsion composition prepared in the same manner as in Example 1 using

Control Example (2) A styrene emulsion composition prepared in the same manner as in Example 1 using a polyoxyethylene alkyl phenyl ether emulsifier 3.51 and a polyoxyethylene alkyl ether sulfonate emulsifier 3.51.

Control Example (3) A water-based varnish (resin content: 25%, pH 9.2) prepared by dissolving a commercially available styrene-maleic acid resin (Hyros X-1227, manufactured by Seiko Kagaku Kogyo) in aqueous ammonia.

(1) Test of mechanical stability and alcohol dilutability of the composition/Mechanical stability test 100g of the composition was placed in a 200rrLl wide robin, and heated to 200Or, 96m, at room temperature with a screw type stirrer for 50 minutes.
Treat for a minute and observe the formation of precipitates.

Evaluation ○: None △: Little ×: Much Alcohol dilutability test Composition 1 (1) was taken in a beaker, Inglobil alcohol was added, and the amount of alcohol added until a coagulated product was formed (% vs. weight of the combined acid) Evaluation 0220 or more ○: 10-20 △: 5-10
X: Less than 5 Results Mechanical stability Alcohol dilution Dissolution Composition of Example 1 (110◎ Composition of Example 2 (2) ○ ○ Composition of Example 3 (3) ○ ◎ Composition of Example 4 (
40◎ Composition of Example (5) (500 Composition of Control Example (1) × × Control Example (
2) Composition △ 200 r, p9m using a kneading tester (Atrike manufactured by Mitsui Seisakusho).

Knead for an hour.

- Ink suitability test 10 parts of the above base ink, 10 parts of the sample composition, and 2 parts of isopropyl alcohol were mixed, and the mixture was spread on a jute liner using a bar coater &8.

At that time, the adhesion, drying properties, and water resistance of the dried coating film are tested.

Adhesion (transferability) is evaluated by the presence or absence of "pasm", dryness is evaluated by touch with the finger, and water resistance is evaluated by lightly rubbing with wet gauze.

Evaluation ○: Good △: Fair ×: Poor Result Adhesion Drying property Water resistance Composition of Example 1 (1) ○ ○ ○ Composition of Example 2 (2) ○ ○ ○ Example 3
0 Composition (3) Composition of Example 4 (4) Example 50 Composition 5) * Composition of Control Example (1) * Composition of Control Example (2) Composition of Control Example (3) △ ○ △ × *Since 2 parts of isopropyl alcohol produced a precipitate, addition of alcohol was omitted.

Claims (1)

[Claims] 1. Using an emulsifier mainly composed of ammonium salt, amine salt, or alkali metal salt of maleic acid mono(polyoxyethylene alkyl ether) ester or maleic acid mono(polyoxyethylene alkyl phenyl ether) ester, styrene is removed in an aqueous medium. A method for producing an aqueous polymeric composition comprising radical emulsion polymerization of a vinyl monomer containing as a main component.