JP5936187B2 - Reactive surfactant - Google Patents

Description

The present invention relates to a reactive surfactant that enables sufficient emulsification and dispersion while preventing the release of excess surfactant, particularly when used for emulsification and dispersion of hydrophobic substances.

The surfactant is contained in the product as a component that is indispensable, for example, in the production of the product in the case of paint, printing ink, adhesive, etc., or in terms of stabilization of the product and workability.
In addition, the surfactant is also used as an emulsifier for emulsion polymerization used in producing a polymer by emulsion polymerization, and is not only involved in polymerization initiation reaction and growth reaction, but also mechanical stability of the produced emulsion, Also involved in chemical stability, freezing stability, storage stability, etc., emulsion properties such as emulsion particle size, viscosity and foaming properties, water resistance when filmed, weather resistance, adhesion, heat resistance It is known that it has a great influence on film physical properties.

However, when a surfactant is used as an emulsifier as described above, since the surfactant is present in a free state in the resin emulsion produced by the emulsion polymerization method, foaming of the emulsion, water resistance of the resin, adhesiveness It has been pointed out as a problem that it adversely affects

In order to improve such problems, reactive surfactants having radical polymerizable double bonds have been developed in addition to the hydrophobic groups and hydrophilic groups of conventional surfactants. Since such a reactive surfactant is copolymerized in the generated polymer chain during emulsion polymerization, it is possible to prevent physical properties from being lowered due to the released surfactant.
For example, Patent Document 1 discloses a novel reactive emulsifier composed of a compound having a dioxolane ring and a copolymerizable unsaturated group, and Patent Document 2 discloses branched aliphatic carbonization as a hydrophobic group. Reactive surfactants having hydrogen groups are disclosed.

On the other hand, in recent years, reactive surfactants have been used to disperse hydrophobic substances and the like. However, reactive surfactants mainly used for polymerization emulsifiers as described above are used with emulsions. Although the adsorptivity is sufficient, when used for dispersion of a hydrophobic substance, there is a problem in that suitable dispersibility cannot be ensured because the adsorptivity to the hydrophobic substance is insufficient.

Further, as a reactive surfactant used not only for emulsifiers for emulsion polymerization but also for resin modifiers, Patent Document 3 discloses a reactive surfactant having a hydrocarbon group having a fluorine atom as a hydrophobic group. Has been. Such reactive surfactants have molecular chains that are more hydrophobic than in the past, so that the physical adsorption to hydrophobic substances is somewhat improved, but the surface of hydrophobic substances derived from chemical bonds can be improved. Since the immobilization is insufficient, there is a problem that a satisfactory result cannot be obtained with respect to the surfactant release preventing effect.

JP 2000-136205 A JP 2002-265505 A JP 2008-24942 A

An object of the present invention is to provide a reactive surfactant that enables sufficient emulsification and dispersion while preventing the release of excess surfactant, particularly when used for dispersing hydrophobic substances.

The present invention is a reactive surfactant that is used as a dispersant for a hydrophobic substance and has a structure represented by the following general formula (1).

式（１）中、Ｘはラジカル重合性反応基、Ｒ^１は炭素数３〜２０の直鎖アルキル基、Ｙは分子量１０００以下であり、かつ、糖類骨格を有するノニオン性親水性基を表す。
以下、本発明を詳述する。

In formula (1), X represents a radical polymerizable reactive group, R ¹ represents a linear alkyl group having 3 to 20 carbon atoms, Y represents a nonionic hydrophilic group having a molecular weight of 1000 or less and having a saccharide skeleton .
The present invention is described in detail below.

In the reactive surfactant of the present invention, the radical polymerizable reactive group represented by X is preferably an ethylenically unsaturated group, and radical polymerization such as (meth) acryloyl group, styryl group, vinyl ester group and vinyl ether group. A highly functional group is more preferable.

As the radical polymerizable reactive group represented by X, any of the radical polymerizable reactive groups represented by the following formulas (2) to (6) is preferably used.
These polymerizable reactive groups have a relatively large value (Q value) related to resonance stabilization of the reactive radical, and the steric hindrance of the substituent bonded to the vinyl group is not large, so that the polymerization reaction is easy. There is an advantage of going forward.

式（２）〜（６）中、Ｒ^２は水素原子又はメチル基を示す。

In formulas (2) to (6), R ² represents a hydrogen atom or a methyl group.

In the reactive surfactant of the present invention, R ¹ is a linear alkyl group having 3 to 20 carbon atoms.
When the number of carbon atoms is less than 3, the hydrophobicity decreases and the adsorptivity to the hydrophobic substance is poor, and when the number of carbon atoms exceeds 20, the polymerizable reactive group is buried in the alkyl chain. As a result, the polymerization reactivity decreases. Preferably it is C4-C12.

Further, as the R ¹ may use a linear alkyl group. When a branched alkyl group is used, not only is the steric hindrance of the polymerization reactive group, the reactivity is lowered, but also it becomes difficult to adsorb with an orientation on a hydrophobic substance, The adsorption density decreases, and the dispersion stabilization effect decreases. Specifically, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, etc. Is preferred. Of these, a butyl group, a hexyl group, an octyl group, and an undecyl group are more preferable.

In the reactive surfactant of the present invention, a nonionic hydrophilic group having a molecular weight of 1000 or less is used as Y.
By having nonionic properties, there is an advantage that hydrophilicity is not easily changed by changes in pH and salt concentration, and dispersion stability can be stably expressed.

The upper limit of the molecular weight of the nonionic hydrophilic group is 1000. When the molecular weight exceeds 1000, the hydrophilic / hydrophobic balance is deteriorated, and the surface active ability is lowered. A preferred upper limit is 600. In addition, although it does not specifically limit about a minimum, 100 or more are preferable.

As said Y, what has saccharide | sugar skeleton is preferable. Molecules having these skeletons can introduce a large number of hydroxyl groups into the hydrophilic unit, and thus have high surface activity ability despite being nonionic.
In order to keep the quality of the surfactant constant, it is preferable to have a monosaccharide skeleton composed of 6-membered rings such as aldohexose and ketohexose, and more preferably a glucose derivative skeleton. Examples of the glucose derivative skeleton include a gluconolactone skeleton and a glucosamine skeleton.

The gluconolactone skeleton means one having a molecular structure obtained by chemically reacting gluconolactone (D-(+)-gluconic acid-δ-lactone) with a base material.
Examples of the gluconolactone skeleton include a structure represented by the following formula (7).

Moreover, the said glucosamine skeleton means what has the molecular structure obtained by making glucosamine chemically react with a base material. Examples of the glucosamine skeleton include a structure shown in the following formula (8).

The reactive surfactant of the present invention is a surface modifier for hydrophobic substances in addition to the applications for which reactive surfactants have been used conventionally, that is, an emulsifier for emulsion polymerization, a dispersant for suspension polymerization, and the like. Can be used for etc. In particular, it can be suitably used as a dispersant for hydrophobic substances such as carbon nanotubes.

When the reactive surfactant of the present invention is used as a dispersant for a hydrophobic substance, it is preferably used in an amount of 1 to 30% by weight based on the hydrophobic substance, depending on the type of the hydrophobic substance. preferable.

When the reactive surfactant of the present invention is used as a dispersant for a hydrophobic substance, it is preferable to provide a process for reacting the reactive surfactant after mixing the reactive surfactant and the hydrophobic substance. .
In addition, when the reactive surfactant is subjected to a polymerization reaction, a polymerization initiator or a monomer copolymerizable with the reactive surfactant may be added separately. As the monomer copolymerizable with the reactive surfactant, a crosslinkable polyfunctional monomer is preferable.
Although it does not specifically limit as a crosslinkable polyfunctional monomer, For example, the following di (meth) acrylate, a tri (meth) acrylate, a diallyl compound, a triallyl compound, a divinyl compound is mentioned, These are used independently. Or two or more of them may be used in combination.

Examples of the di (meth) acrylate include divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and 1,4-butanediol di (Meth) acrylate, etc. are mentioned.
Examples of the tri (meth) acrylate include trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate.
Examples of the divinyl compound include divinylbenzene.

According to the reactive surfactant of the present invention, particularly when used for emulsifying and dispersing hydrophobic substances, sufficient emulsifying and dispersing can be achieved while preventing the release of excess surfactant.

Examples of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Production Example 1)
In the flask, 21.7 g (0.100 mol) of 6- (tert-Butoxycarbonylamino) -1-hexanol was added to 500 ml of ethyl acetate and dissolved by stirring. Thereafter, 15.9 g (0.150 mol) of sodium carbonate was added and stirred for a while. 11.5 g (0.110 mol) of methacryloyl chloride was dissolved in 30 ml of ethyl acetate and added to the solution prepared above using an equilibrium dropping funnel. After completion of the dropping, the reaction was allowed to stir for 2 hours. After completion of the reaction, the solid component was removed by suction filtration, and then the solvent of the filtrate was distilled off under reduced pressure using an evaporator to obtain a reaction intermediate (a-1).
625 ml of 4N-Hydrogen chloride ethyl acetate solution (manufactured by Watanabe Chemical Co., Ltd.) was added to the intermediate (a-1), and the mixture was stirred for 2 hours. After completion of the reaction, HCl was neutralized with a 10% by weight aqueous solution of sodium carbonate, and the organic phase was recovered using a separatory funnel. From the recovered organic phase, the solvent was distilled off under reduced pressure at room temperature using an evaporator to obtain an intermediate (a-2).
To the flask was added 5.98 g (0.0323 mol) of intermediate (a-2), 7.21 g (0.0400 mol) of D (+)-Glucono-1,5-lactone and 1.00 g of sodium nitrate as a polymerization inhibitor. Nitrogen replacement was performed.
After completion of the substitution, 500 ml of ethanol was added and refluxed for 6 hours.
After completion of the reaction, the solid component was removed by suction filtration, and then the filtrate was distilled off under reduced pressure at room temperature using an evaporator. The residue was dissolved in 1,4-dioxane. Thereafter, suction filtration was performed to remove the solid components, and then the solvent was distilled off under reduced pressure using an evaporator. This was lyophilized for 24 hours to obtain 8.11 g (0.0223 mol) of a reactive surfactant (A). Table 1 shows the chemical formula of the reactive surfactant (A).

(Production Example 2)
In Production Example 1 except that 18.9 g (0.100 mol) of 4- (tert-Butoxycarbonylamino) -1-butanol was used instead of 21.7 g (0.100 mol) of 6- (tert-Butoxycarbonylamino) -1-hexanol Similarly, a reactive surfactant (B) was synthesized. Table 1 shows the chemical formula of the reactive surfactant (B).

(Production Example 3)
A reactive surfactant (C) was synthesized according to Production Example 1 except that 15.2 g (0.110 mol) of chlorostyrene was used instead of 11.5 g (0.110 mol) of methacryloyl chloride. Table 1 shows the chemical formula of the reactive surfactant (C).

(Production Example 4)
A reactive surfactant (D) was synthesized according to Production Example 1 except that 16.8 g (0.110 mol) of chloroallylbenzene was used instead of 11.5 g (0.110 mol) of methacryloyl chloride. Table 1 shows the chemical formula of the reactive surfactant (D).

(Production Example 5)
In a flask, 22.7 g (0.100 mol) of 8-Bromo-1-octanol was added to 500 ml of ethyl acetate and dissolved by stirring. Thereafter, 15.9 g (0.150 mol) of sodium carbonate was added and stirred for a while. 11.5 g (0.110 mol) of methacryloyl chloride was dissolved in 30 ml of ethyl acetate and added to the solution prepared above using an equilibrium dropping funnel. After completion of the dropping, the reaction was allowed to stir for 2 hours. After completion of the reaction, the solid component was removed by suction filtration, and then the solvent of the filtrate was distilled off under reduced pressure using an evaporator to obtain a reaction intermediate (e-1).
10.7 g (0.0412 mol) of the intermediate (e-1), 8.96 g (0.0500 mol) of glucosamine and 1.00 g of sodium nitrate as a polymerization inhibitor were added to the flask, and nitrogen substitution was performed.
After completion of the substitution, 500 ml of ethanol was added and the reaction was performed at 80 ° C. for 6 hours.
After completion of the reaction, the solid component was removed by suction filtration, and then the filtrate was distilled off under reduced pressure at room temperature using an evaporator. The residue was dissolved in 1,4-dioxane. Thereafter, suction filtration was performed to remove the solid components, and then the solvent was distilled off under reduced pressure using an evaporator. This was lyophilized for 24 hours to obtain 11.1 g (0.0313 mol) of a reactive surfactant (E). Table 1 shows the chemical formula of the reactive surfactant (E).

(Production Example 6)
A reactive surfactant according to Production Example 5 except that 32.1 g (0.100 mol) of 16-Bromo-1-hexadecanol was used instead of 22.7 g (0.100 mol) of 8-Bromo-1-octanol. F) was synthesized. Table 1 shows the chemical formula of the reactive surfactant (F).

(Production Example 7)
Reactive surfactant according to Production Example 5 except that 12.5 g (0.100 mol) of 2-Bromo-1-ethanol was used instead of 22.7 g (0.100 mol) of 8-Bromo-1-octanol G) was synthesized. Table 1 shows the chemical formula of the reactive surfactant (G).

(Production Example 8)
According to Production Example 5 except that 75.0 g (0.0500 mol) of aminopolyoxyethylene (molecular weight: about 1500, number of oxyethylene units = about 50) was used instead of 8.96 g (0.0500 mol) of glucosamine. A reactive surfactant (H) was synthesized. Table 1 shows the chemical formula of the reactive surfactant (H).

(Production Example 9)
1.70 g (0.0400 mol) of 1-Bromooctane, 8.96 g (0.0500 mol) of glucosamine and 1.00 g of sodium nitrate as a polymerization inhibitor were added, and nitrogen substitution was performed.
After completion of the substitution, 500 ml of ethanol was added and the reaction was performed at 80 ° C. for 6 hours.
After completion of the reaction, the solid component was removed by suction filtration, and then the filtrate was distilled off under reduced pressure at room temperature using an evaporator. The residue was dissolved in 1,4-dioxane. Thereafter, suction filtration was performed to remove the solid components, and then the solvent was distilled off under reduced pressure using an evaporator. This was lyophilized for 24 hours to obtain 8.30 g (0.0294 mol) of reactive surfactant (I). Table 1 shows the chemical formula of the reactive surfactant (I).

Example 1
Carbon nanotubes (manufactured by Aldrich) 50 mg and reactive surfactant (A) 50 mM aqueous solution 100 ml were weighed in a flask, and subjected to ultrasonic waves to disperse the carbon nanotubes in the aqueous solution. Add 6.5 mg (0.0500 mmol) of divinylbenzene as a crosslinkable monomer, and 8.2 mg (0.0500 mmol) of 2,2'-Azobis (2-methylpropionamidine) dihydrochloride (trade name, V-50) as a polymerization initiator. Then, nitrogen substitution in the flask was performed. Reaction was performed at 70 ° C. for 4 hours to obtain a surface-treated carbon nanotube dispersion.

(Example 2)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (B) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Example 3)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (C) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

Example 4
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (D) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Example 5)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (E) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Example 6)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (F) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Example 7)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that divinylbenzene was not added as a crosslinkable monomer.

(Comparative Example 1)
Carbon nanotubes (Aldrich) 50 mg and polyoxyethylene dodecyl ether (Daiichi Kogyo Seiyaku Co., Ltd., DSK NL-70) 50 mM aqueous solution 100 ml are weighed in a flask and subjected to ultrasonic waves to disperse the carbon nanotubes in the aqueous solution. A nanotube dispersion was obtained.

(Comparative Example 2)
A carbon nanotube dispersion was obtained in the same manner as in Comparative Example 1 except that a 50 mM aqueous solution of the reactive surfactant (I) was used instead of the 50 mM aqueous solution of polyoxyethylene dodecyl ether.

(Comparative Example 3)
Reactive surfactant (A) Nonionic reactive surfactant (polyoxyethylene nonylpropenyl phenyl ether, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aqualon RN-10) 50 mM aqueous solution was used in place of the 50 mM aqueous solution. A carbon nanotube dispersion was obtained in the same manner as in Example 1.

(Comparative Example 4)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (A) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Comparative Example 5)
A carbon nanotube dispersion was obtained in the same manner as in Example 1 except that the reactive surfactant (A) 50 mM aqueous solution was used instead of the reactive surfactant (A) 50 mM aqueous solution.

(Evaluation method)
The performance of the surfactant obtained above was evaluated by the following method. The results are shown in Table 2.

(Evaluation of dispersion stability by washing operation)
The carbon nanotubes obtained above were weighed in a beaker with 30 ml of a dispersion and 30 ml of diethyl ether and mixed vigorously with a stirrer for 3 minutes. Thereafter, the mixture was allowed to stand for 10 minutes to confirm that it was completely separated into two layers, and the upper diethyl ether phase was removed. 30 ml of diethyl ether was again added to the remaining carbon nanotube dispersion, and the washing operation was repeated in the same manner. After repeating the above washing operation three times, the state of the aqueous phase was observed to confirm the dispersibility of the carbon nanotubes. After standing for 30 minutes, a solid sedimentation deposit that could be visually confirmed was defined as “precipitation”, and a solid sediment that could not be confirmed was defined as “dispersion”.

(Dispersion stability evaluation by dialysis)
The carbon nanotubes obtained above were sealed in 20 ml of a pretreated dialysis membrane and immersed in ion exchange water for 24 hours. A dialysis membrane having a fractional molecular weight of 15,000 was used. The state in the film was observed to confirm the dispersibility of the carbon nanotubes. After standing for 30 minutes, a solid sedimentation deposit that could be visually confirmed was defined as “precipitation”, and a solid sediment that could not be confirmed was defined as “dispersion”.

According to the present invention, it is possible to provide a reactive surfactant capable of sufficient emulsification and dispersion while preventing the release of excess surfactant, particularly when used for emulsification and dispersion of hydrophobic substances. .

Claims (3)

A reactive surfactant used as a dispersant for a hydrophobic substance, wherein the reactive surfactant has a structure represented by the following general formula (1).

In formula (1), X represents a radical polymerizable reactive group, R ¹ represents a linear alkyl group having 3 to 20 carbon atoms, Y represents a nonionic hydrophilic group having a molecular weight of 1000 or less and having a saccharide skeleton . The reactive surfactant according to claim 1, wherein X in the formula (1) is any of radically polymerizable reactive groups represented by the following formulas (2) to (6).

In formulas (2) to (6), R ² represents a hydrogen atom or a methyl group. The reactive surfactant according to claim 1 or 2, wherein Y in the formula (1) has a monosaccharide skeleton composed of a six-membered ring.