JPH0547259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to anionic polymeric surfactants.

More specifically, the present invention relates to a novel anionic water-soluble copolymer composition having unprecedented surface active ability.

Specifically, at least three of (A) acrylic acid or methacrylic acid, (B) acrylonitrile or methacrylonitrile, and (C) acrylamide alkyl sulfonic acid or sulfoalkyl acrylate.
The present invention relates to an anionic polymeric surfactant that is composed of a multicomponent copolymer of more than one type of vinyl monomer and has a special function that has never been seen before.

Surfactants are used in a wide variety of applications such as emulsification, dispersion, dissolution, and antifoaming, and are used as extremely useful means in industry.

As described in many books, such surfactants include anionic, cationic,
It is broadly classified into nonionic compounds, and a large number of compounds or compositions have been proposed in the past, and they are used alone or in mixtures.

Among these, in recent years, various oligomer or polymer surfactants called polymeric surfactants have attracted attention due to their unique performance, and they have improved dispersion and conductivity, which were difficult to achieve with conventional surfactants. It came to be used for purposes such as imparting sex.

In recent years, the application of such polymeric surfactants to increasingly sophisticated special uses has come to be considered.

A specific application of such a special polymeric surfactant is as a system modifier for forming microcapsules using an aminoaldehyde resin film by in-situ polymerization.

The industrial application of microencapsulation technology is in the field of pressure-sensitive copying paper, and in recent years microcapsules have been used in large quantities in this field.

The manufacturing method of microcapsules for pressure-sensitive copying paper has been around for a long time, using gelatin and gum arabic or carboxymethylcellulose (CMC) to physicochemically generate micron-sized oil droplets in a high-boiling solvent in which a dye precursor is dissolved. The so-called complex coacervation method is used. However, according to this method, (1) it is not possible to obtain a microcapsule slurry with a concentration exceeding 20%, and a large amount of water must be evaporated when coating pressure-sensitive copying paper; There is a great need for improvements in terms of speed and energy costs; (1) the volumetric efficiency during microcapsule production is low and transportation costs are high; and (3) quality is poor because the capsule membrane material is a natural product. It has basic problems such as large fluctuations in surface and price, and (4) it cannot withstand long-term storage because it has a tendency to rot and agglomerate.

Therefore, in recent years, a microencapsulation method has begun to be used in which a hydrophobic material is coated with an aminoplast polycondensate film produced by an in-situ polymerization method. These are published in Japanese Unexamined Patent Application Publication No. 51-9079 and 53-9079.
As known from Publication No. 84881, a hydrophobic high-boiling solvent is emulsified into minute oil droplets in the presence of an anionic polymeric surfactant, and polycondensation of urea formaldehyde resin or melamine aldehyde resin is carried out on the spot. In this method, a hydrophobic substance is coated with a film of aminoaldehyde resin.

According to this method, compared to the complex coacervation method, a microcapsule slurry with a high solid content can be obtained, and the membrane has excellent density.
It also has excellent features that have never existed before, such as not having a tendency to rot.

This in-situ polymerization method is used to produce microcapsules.

Anionic polymer surfactants (hereinafter referred to as system modifiers) are required to have the following performance. That is, (1) the ability to emulsify a hydrophobic liquid O/W, to form a stable emulsion system, and this emulsion system has a low viscosity; (2) the aminoaldehyde resin formed under acidic conditions; (3) The hydrophobic substance coated with aminoaldehyde resin can be dispersed in water at high concentration and low viscosity. etc.

However, nothing is known that actually fully satisfies the above performance.

For example, anionic polymers that have been proposed as system modifiers in the production of such in-situ polymerized microcapsules include polyacrylic acid, ethylene maleic anhydride copolymer, and vinyl acetate maleic anhydride copolymer. Various (water-soluble) anionic polymers such as polymer, styrene maleic anhydride copolymer, polystyrene sulfonic acid, carboxy-modified polyvinyl alcohol, and sulfonic acid-modified polyvinyl alcohol, or their salts are known, and some are actually used, but these can be used to produce in-situ products with a solid content of 50wt% or more.
Polymerized microcapsules have not yet been produced industrially.

In view of the above problems, the inventors of the present invention
As a result of various studies on anionic polymeric surfactants, we found that the following new multi-component copolymer has special functions, and has a hydrophobic property due to the amino-aldehyde resin wall formed by in-situ polymerization. It has been discovered that the present invention has an extremely excellent effect on microencapsulation of substances, and the present invention has been achieved.

That is, the novel anionic polymer surfactant of the present invention is (A) acrylic acid and/or methacrylic acid, (B) acrylonitrile and/or methacrylonitrile, (C) acrylamide alkyl sulfonic acid and/or sulfoalkyl acrylate. This is an anionic polymeric surfactant made of a multi-component copolymer of at least one vinyl monomer or a salt thereof consisting of at least one vinyl monomer selected from (A), (B), and (C).

The novel multicomponent copolymer and its salt of the present invention are
It is produced by copolymerizing three or more vinyl monomers selected from the above three components.

That is, it consists of components each selected from three components: (a) acrylic acid and/or methacrylic acid, (b) acrylonitrile and/or methacrylonitrile, and (c) acrylamide alkyl sulfonic acid and/or sulfoalkyl acrylate. It is a multidimensional copolymer.

From the viewpoint of easy availability of raw materials, copolymerizability, effect as a special surfactant, etc., the three components (A) acrylic acid, (B) acrylonitrile, and (C) acrylamide alkyl sulfonic acid are preferably used as essential monomer components. It is a multicomponent copolymer.

The above acrylamide alkyl sulfonic acid has the general formula () (R is a lower alkylene group), specifically, acrylamide methanesulfonic acid, acrylamide ethanesulfonic acid, acrylamide propanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid,
Examples include 2-acrylamido-n-butanesulfonic acid.

In addition, sulfoalkyl acrylate has the general formula () (R' represents a lower alkylene group), and specific examples include sulfomethyl acrylate, sulfoethyl acrylate, sulfopropyl acrylate, and sulfobutyl acrylate.

If necessary, in addition to the above three components, hydroxyethyl ester, hydroxypropyl ester, lower alkyl ester, acrylamide, methacrylamide, methylolacrylamide, N-alkyl-substituted acrylamide, etc. of acrylic acid or methacrylic acid may be added. May be added.

The composition of the above three components is (A) component 20 to 70 mol%;
Component (B) is preferably 5 to 60 mol%, and component (C) is preferably 1 to 30 mol%.

Polymerization methods include ionic polymerization, radical polymerization, thermal polymerization, radiation polymerization, etc., but radical copolymerization is preferred, and generally a system in which three or more of the above-mentioned vinyl monomers are uniformly dissolved in water is used. Radical polymerization methods are often used.

Examples of polymerization catalysts include various organic peroxides (e.g. benzoyl peroxide), organic hydroperoxides,
Examples include radical polymerization initiators such as aliphatic azobisnitriles (e.g. azobisisobutyronitrile), water-soluble persalts (e.g. persulfates), etc.
Since the polymeric surfactant of the present invention preferably has a relatively low molecular weight (low viscosity of aqueous solution), the most preferably used catalysts are water-soluble peracids (ammonium persulfate, potassium persulfate) and water-soluble reducing agents (e.g., It is a redox radical-forming catalyst for use in combination with sulfites). These redox radical-forming catalysts are generally added to the reaction system as an aqueous solution. The amount of catalyst added is per 100 parts by weight of monomer components for both water-soluble peracids and water-soluble reducing agent.
Added from 0.01 to 10 parts.

In order to control the molecular weight of the resulting polymer, a small amount of various compounds known as chain transfer agents, such as alkyl mercaptans, may be added to the reaction system for reaction.

When polymerizing a vinyl monomer in an aqueous solution, the monomers having an acidic group may be in the free acid form, or part or all may be subjected to the polymerization in the form of a salt. When used in the form of a salt, it is used in the form of an alkali metal salt, an alkaline earth metal salt, an ammonium salt, a lower amine salt, a hydroxyalkylamine salt, or the like.

When producing the polymer surfactant of the present invention by an aqueous radical polymerization method, after adding catalysts,
The rapid generation of polymerization heat causes an adiabatic temperature rise in the system, and the polymerization reaction is completed in a relatively short time. Generally, in order to avoid boiling of the system, the polymerization reaction is carried out as a 5 to 30 wt % aqueous solution, taking into consideration the polymerization heat of each monomer.

The polymer surfactant of the present invention can be used in a wide variety of ways by selecting the ratio of the three raw materials within the above range.
The viscosity of an aqueous solution with 20 wt% non-volatile content, which is soluble over the PH range, is 5-100000 cps (at 25°C,
(measured using a B-type viscometer under the condition of PH4.0) is common, and a polymer surfactant with a yield of 10 to 10,000 cps is used as a preferred polymeric surfactant.

As mentioned above, the polymeric surfactant of the present invention is generally handled as an aqueous solution from the stage of polymerization of monomers, so when used as a polymeric surfactant, no additional dissolution operation in water is required. Therefore, it is very easy to handle. Of course, it is also possible to handle it as a dry powder if necessary.

The polymer surfactant of the present invention can be used in the above-mentioned In-Situ
Polymerized aminoaldehyde resin film (urea formaldehyde resin film, melamine formaldehyde resin film) as a system modifier for microcapsule production.
It exhibits extremely superior functionality compared to various known water-soluble anionic polymers. Specifically, (1) O/W hydrophobic liquid with high concentration and low viscosity.
It can be a type emulsion. There is no tendency for phase reversal, and the O/W emulsion thus obtained has excellent emulsion stability.
There is no tendency for particle growth due to coalescence of emulsion particles.

(2) When forming microcapsules, a dense aminoaldehyde resin film can be formed on the surface of a hydrophobic substance.

(3) The formed microcapsules of hydrophobic material coated with an aminoaldehyde resin film were
It can be stably dispersed to an ultra-high degree exceeding 10% and with a low viscosity.

(4) The viscosity of the finished microcapsule slurry has a small dependence on pH, and there is no tendency to increase the viscosity even when the slurry becomes alkaline.

It can provide excellent ultra-high concentration, low viscosity microcapsule slurry.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 2-acrylamido-2-methylpropanesulfonic acid (manufactured by Nippon Lubrizol; “AMPS-R”)
After dissolving 107 parts (parts by weight; the same applies hereinafter) in 1413 parts of ion-exchanged water, it was dissolved in a 10% caustic soda aqueous solution.
The pH was adjusted to 7.0. 229 parts of 98% acrylic acid and 83 parts of acrylonitrile were added to obtain a homogeneous aqueous solution.

(The molar composition of the raw material is 2-acrylamide-2
- Methylpropanesulfonic acid 10 mol%, acrylic acid 60 mol%, acrylonitrile 30 mol%) After warming the system to 40°C, 112.5 parts of a 10% aqueous solution of ammonium persulfate was added with gentle stirring, followed by addition of sodium bisulfite. 10% aqueous solution
When 20 parts were added, polymerization started with heat generation, the temperature of the system rose to 85°C in 30 minutes, and the heat generation stopped. After maintaining this temperature for an additional 30 minutes, it was cooled, and then a 20% NaOH aqueous solution was added to adjust the pH to 4.0 to complete the reaction.

The copolymer aqueous solution has a solid content of 20wt%.
It showed a viscosity of 190 cps (B-type viscometer, 25°C).

Example 2 Sulfopropyl acrylate sodium salt 50%
64.8 parts of an aqueous solution (Osaka Organic Products) was dissolved in 284.7 parts of pure water. Next, 29.15 parts of 98% acrylic acid and 18.55 parts of acrylonitrile were added to form a homogeneous aqueous solution with stirring. While keeping the system warm at 30°C with gentle stirring, add a 20% aqueous solution of ammonium persulfate16.
When 4 parts of a 20% aqueous solution of sodium bisulfite were added, polymerization started with rapid heat generation, and the temperature of the system rose to 72°C in 15 minutes, and the heat generation stopped. This temperature was further maintained for 1 hour and then cooled to obtain a 20% aqueous solution of a pale yellow transparent copolymer.
The pH of the solution was 1.9.

The pH of the aqueous solution adjusted to 4.0 by adding 20% NaOH was 720 cps at 25°C (using a B-type viscometer).

In this example, the copolymerization is performed using sulfopropyl acrylate.
It has a monomer composition of 15 mol%, acrylic acid 55 mol%, and acrylonitrile 35 mol%.

Reference Example 1 An aqueous solution (PH4 .0),
Crystal violet lactone as core material
Add 130 parts of phenylxylylethane (Nippon Petrochemical "Hisol SAS-296") in which 2.8% by weight and 0.8% by weight of benzoyl leucomethylene blue are dissolved, and emulsify for 5 minutes at 9000 rpm using a homomixer (manufactured by Tokushu Kika). O/W with an average particle size of 3.8μ
A mold-stable emulsion was obtained. Subsequently, with stirring, 24.4 parts of methylated methylolmelamine resin ("Resimene 714" manufactured by Monsanto...with 80% non-volatile content) was added, and the system was then heated to 60°C.
After condensing for 2 hours, the mixture was cooled to complete microencapsulation. Although the microcapsule slurry has a high concentration of 63wt%,
It had a low viscosity of 430 cps. To remove residual formaldehyde, add 28% ammonia water to adjust the pH.
When it was set to 8.0, the formaldehyde odor disappeared.
A high-quality microcapsule slurry with a viscosity of 210 cps without agglomeration was obtained.

The microcapsule slurry has a pH range of 2-12.
There is almost no viscosity change over the pH range, and it has good adaptability to coating under various conditions. The microcapsules in this example exhibit low viscosity at high concentrations, which was previously unimaginable, making it possible to adjust high-concentration coating colors, speeding up coating, and facilitating coating using printing methods such as gravure and flexography. I can handle it.

Reference Example 2 20% of the acrylic acid-acrylonitrile-sulfopropyl acrylate copolymer obtained in Example 2
After diluting 25 parts of the aqueous solution with water to a pH of 78.3 (PH4.0), 25 parts of methylated methylol melamine resin (Mitsui Toatsu "Euramine p-6300") with a non-volatile content of 80% was added to form a mixed solution. Furthermore, 100 parts of the same core substance as in Reference Example 1 was added and emulsified. When the average particle size reached 3.5μ, the mixture was heated and stirred for 3 hours in a hot water bath at 55°C to complete condensation, and then cooled to form microcapsules. finished.

The microcapsule slurry in this example is 60.0wt%
It had a viscosity of 20 cps at 25°C.

Comparative example 1 Ethylene maleic anhydride (Monsanto “EMA”
-31'') was heated and dissolved in 450 parts of water to obtain a 10% aqueous solution.

100 parts of this aqueous solution and 200 parts of water were mixed, and the pH was adjusted to 4.0 with a 10% aqueous sodium hydroxide solution.

In this, 200 parts of the same core material as in Reference Example 1 was emulsified using a homomixer, and after 10 minutes, the average particle size was
A stable O/W emulsion of 4.2μ was formed. Subsequently, 32.5 parts of methylated methylolmelamine resin (Resimene 714) was added while stirring, heated to 55°C, condensed for 3 hours, and then cooled to complete microencapsulation.

The microcapsule liquid of this example has a solid content concentration of 44.3 wt%, but the viscosity of the system increases significantly as the wall film formation due to condensation of the melamine formaldehyde initial condensate progresses, and the viscosity of the system increases significantly after the film formation. Although microcapsule slurry has no tendency to agglomerate,
It showed a high viscosity of over 6000 cps and almost lost its fluidity.

Comparative Example 2 Comparative Example 1 except that the solid content of the finished microcapsule slurry was adjusted to 35 wt%
Microencapsulation was completed in the same manner as above. The microcapsule slurry in this example has a pH of 4.8 after cooling.
It showed a viscosity of 180 cps. When the pH was adjusted to 8.0 by adding 28% aqueous ammonia to remove residual formaldehyde, the formaldehyde odor completely disappeared, but the capsule slurry thickened to a viscosity of 420 cps, indicating a large viscosity/PH dependence. was observed, and it was necessary to pay sufficient attention to pH control during coating work.

Comparative Example 3 Sodium styrene sulfonate (Toyo Soda "Spinomer SS" 8.4 parts dissolved in 161.3 parts of water, then 98%
% acrylic acid and 6.5 parts of hydroxyethyl methacrylate (HEMA) were added and stirred to form a homogeneous aqueous solution and kept at 40°C. When 12.9 parts of a 10% aqueous solution of ammonium persulfate and 4.0 parts of a 10% aqueous solution of sodium bisulfite salt were added to start radical polymerization, the internal temperature rose to 65°C in 30 minutes.

The polymerization was further kept at 70℃ for 30 minutes, and the solid content was 20
% anionic water-soluble polymer aqueous solution was obtained. The viscosity of this product was 4800 cps at 25°C and pH 4.0.

Microencapsulation was carried out in the same manner as in Reference Example 1 except that this anionic water-soluble polymer was used instead of acrylic acid-acrylonitrile-2-acrylamido-2-methylpropanesulfonic acid copolymer.

The mixture was stirred and emulsified using a homomixer for 20 minutes to obtain an O/W type emulsion. The emulsion stability was somewhat insufficient, and if left as is, the oil droplets tended to coalesce and the size of the oil droplets increased, so it was necessary to continuously apply strong shearing force. When melamine-formaldehyde initial condensate (Resimene 714) was added to start film formation, the viscosity of the entire product increased significantly and gelled after 10 minutes.

Comparative Example 4 40 parts of 2-acrylamido-2-methyl-propanesulfonic acid was stirred and dissolved in 160 parts of water, and then 20%
The pH was adjusted to 5.0 with an aqueous solution of caustic soda, 3.7 parts of a 10% aqueous solution of potassium persulfate and 0.8 parts of a 10% aqueous solution of sodium hydrogen sulfite were added, and the mixture was polymerized under adiabatic conditions to form a poly(2. −
A 20 wt % aqueous solution (D) of the sodium salt of acrylamide-2-methylpropanesulfonic acid (acrylamido-2-methylpropanesulfonic acid) was obtained.

(4-1) Using this aqueous solution (D), microencapsulation was carried out in a constant temperature water bath at 60°C. Aqueous solution (D)25
1 part and 85 parts of water were stirred and mixed, and the pH was adjusted to 4.0 with acetic acid. In this system, 100% of the same core material as in Reference Example 1 was added.
of the mixture was added and emulsified and dispersed for 20 minutes using a homomixer. The O/W type emulsion of this example has poor emulsification stability, and as soon as stirring, which has a strong shear force, is stopped, the oil droplets coalesce, so it is necessary to constantly apply a strong shear force, and the emulsified droplets control of the size was very difficult.

When 25 parts of methylated methylol melamine (Resimene 714) was added to the mixture under strong stirring, the system rapidly thickened and the entire system coagulated into a gel after 5 minutes.

(4-2) On the other hand, methylated methylolmelamine (Resimene714), which has the same composition as above, was carefully added dropwise under strong stirring over a period of 2 hours to prevent gelation of the system.
The reaction was carried out at 55°C for an hour to complete the microencapsulation. Due to the poor emulsion stability against oil, the resulting microcapsules contained many coarse particles and aggregated particles, and were inconvenient for use in pressure-sensitive copying paper unless they were passed through a sieve. The average particle size was 7.4μ, the solid content was 50wt%, and the viscosity was 420cps.

Example 3 After dissolving 43.2 parts of 2-acrylamido-2-methylpropanesulfonic acid in 564 parts of water, 10%
The pH was adjusted to 7.5 with NaOH. 76 parts of 98% acrylic acid and 44 parts of acrylonitrile were added to the aqueous solution and stirred to become a homogeneous aqueous solution. After keeping the aqueous solution at 45℃, 10% ammonium persulfate,
When 46.8 parts and 10.4 parts of 10% sodium bisulfite were added, a polymerization reaction occurred with exothermic heat, and the internal temperature rose to 90°C in 30 minutes. Furthermore, 4.0 parts of a 10% sodium bisulfite aqueous solution was added, and the mixture was reacted for 1 hour and then cooled to obtain a polymer aqueous solution. The copolymer in this example was 20wt% at PH4.0.
It had a viscosity of 240 cps.

Reference Example 3 Microcapsules were prepared as follows using the copolymer aqueous solution of Example 3. After diluting 20 parts of the copolymer aqueous solution with a solid content of 20 wt% with water to 80 parts, methylated methylol was added. Melamine (Sumitomo Chemical Sumiretsu Resin #618, with 80% solids content)
Added 20 copies.

After stirring at room temperature for 30 minutes, 3-diethylamino-6-methyl-7-phenylaminofluorane
5.0wt%, Crystal Violet Lactone 0.4wt
100 parts of diisopurnaphthalene (Kureha Chemical Co., Ltd., "KMC-113") in which 10% was dissolved was added and emulsified for 5 minutes using a homomixer to obtain a stable O/W emulsion with an average particle size of 3.7 .mu.m. Gently stir the system while stirring.
The mixture was heated to 65°C and the reaction was carried out for 2 hours. even smaller amount
After adjusting the pH to 4.3 by adding 20% acetic acid, the mixture was further stored at 65°C for 1 hour to complete microencapsulation.

The microcapsule slurry was adjusted to pH 8.5 with 28% aqueous ammonia to remove formalin. The obtained microcapsules are spherical microcapsules with an average particle size of 3.7 μm and a narrow distribution width, and the solid content is
The viscosity at 60 wt% was extremely low at 95 cps.

Using this microcapsule slurry, we created a 45wt% water-based paint with the following composition, and the viscosity was
35cps and 50g/ ^m2 with air knife coater
It was possible to coat on high quality paper with a dry coverage of 6 g/m ² .

Reference Example 4 25 parts of the aqueous copolymer solution obtained in Example 3 was diluted with water to make 128.7 g, and then the pH was adjusted to 3.4 with a 20% acetic acid aqueous solution.
And so. Furthermore, 5 parts of urea and 0.5 parts of resorcin were added and dissolved, and the same core material used in Reference Example 3 was added and dissolved therein.
When 100 parts were added and emulsified for 20 minutes using a homomixer, a stable O/W type emulsion with an average particle size of 4μ was obtained. Subsequently, 14 parts of 37% formalin was added while stirring, and condensation was carried out at 55°C for 5 hours to complete microencapsulation. The microcapsule slurry has a solids content of 52wt% and 180cps
It had a viscosity of (25°C) and was useful for pressure-sensitive copying paper for black coloring.

Claims (1)

[Claims] 1 (a) Acrylic acid and/or methacrylic acid20
(b) 20 to 60 mol% of acrylonitrile and/or methacrylonitrile, and (c) 1 to 30 mol% of acrylamide alkyl sulfonic acid and/or sulfoalkyl acrylate, and % aqueous solution PH4.0,
An anionic polymeric surfactant used in the production of microcapsules formed by forming an aminoaldehyde resin film by in-situ polymerization of multicomponent copolymerization or a salt thereof having a viscosity of 5 to 100,000 cps at 25°C.