JP3084156B2 - Polymerizable magnetic fluid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic fluid. More specifically, the present invention relates to a polymerizable magnetic fluid comprising magnetic fine particles treated with a specific surfactant and a polymerizable dispersion medium.

[0002]

2. Description of the Related Art Magnetic fluids are used in the field of magnetic fluid seals, optical materials, and the like because of their unique properties, such as behaving as a ferromagnetic liquid. Generally, a magnetic fluid is composed of magnetic fine particles, a surfactant, and a dispersion medium. In recent years, attempts have been reported to produce a new magnetic film for use in magnetic shielding, visualization of magnetic recording patterns, magnetic flaw detection, and the like, using a polymerizable monomer as a dispersion medium. Further, the polymerizable magnetic fluid is used as a magnetic fluid adhesive for connecting magnetic materials.

Conventionally, in the production of magnetic fluids, compounds having a bent molecular skeleton, such as oleic acid and linoleic acid, or compounds having a large number of functional groups or side chains in one molecule are used as surfactants. Was used. However, it is not easy to stably disperse the magnetic fine particles in the polymerizable dispersion medium with such a surfactant, and a large amount of the surfactant is required for dispersion. In addition, excessive use of a surfactant causes poor curing during polymerization of the dispersion medium.

[0004] In addition, although conventional surfactants are used in excess, undesirable phenomena such as unexpected increase in viscosity and solidification occur together. This phenomenon appears remarkably when a polymerizable dispersion medium comprising a polyfunctional monomer which is more easily polymerized is used. It is considered that the magnetic particles acted as a catalyst to cause radical polymerization. As a measure to prevent polymerization,
It is effective to 1) mix a polymerizable dispersion medium with a non-polymerizable dispersion medium, and 2) use a polymerization inhibitor. However, these measures tend to reduce the curability after polymerization.

[0005]

Therefore, a polymerizable magnetic fluid which exhibits stable dispersibility of magnetic fine particles, does not undergo polymerization during storage, and cures only during polymerization has been desired.

[0006]

Means for Solving the Problems The present inventors show stable dispersibility of magnetic fine particles, do not cause polymerization during storage,
As a result of repeated studies to develop a polymerizable magnetic fluid that cures only at the time of polymerization, the present inventors have found that an intended magnetic fluid can be obtained by using a specific surfactant, and have completed the present invention.

That is, the present invention provides:

[0008]

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Wherein R is an alkyl group having 1 to 12 carbon atoms, n is an integer of 1 to 25, and m is an integer of 10 to 12; The present invention relates to a magnetic fluid comprising fine particles and (c) a polymerizable dispersion medium.

Still another invention relates to (a) a general formula:

[0011]

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Wherein R is an alkyl group having 1 to 12 carbon atoms, n is an integer of 1 to 25, and m is an integer of 10 to 12; Fine particles,
A polymerizable magnetic fluid comprising (c) a polymerizable dispersion medium and (d) a polymerization initiator.

In the above general formula, a surfactant in which R is a hydrogen atom, a surfactant in which n is 0, or a surfactant in which m is less than 10 is used as a surfactant for a polymerizable magnetic fluid. When used, the dispersibility of the magnetic fine particles is reduced, and the polymerization of the dispersion medium is likely to occur during storage. A surfactant wherein R is an alkyl group having more than 12 carbon atoms;
In the case of a surfactant exceeding m or a surfactant having m of 13 or more, not only is it difficult to obtain raw materials and synthesis is difficult, but also as a surfactant necessary for synthesis of a polymerizable magnetic fluid. In addition to an increase in the amount, which is not economical, polymerizable magnetic fluids prepared using them are liable to cause poor curing during polymerization.

Specific examples of the surfactant represented by the above general formula of the present invention include CH ₃ O (C ₂ H ₄ O) ₂ (C
_{H 2) 10 COOH, CH 3} O (C 2 H 4 O) 2 (CH 2) 11 C
OOH, CH ₃ O (C ₂ H ₄ O) ₂ (CH ₂ ) ₁₂ COOH,
CH ₃ O (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH, CH ₃ O
(C ₂ H ₄ O) ₃ (CH ₂ ) ₁₁ COOH, CH ₃ O (C ₂ H ₄
O) ₃ (CH ₂ ) ₁₂ COOH, H (C ₂ H ₄ O) ₃ (CH ₂ )
₁₀ COOH, H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₁ COOH, H
(C ₂ H ₄ O) ₃ (CH ₂ ) ₁₂ COOH, C ₄ H ₉ OC ₂ H ₄ O
(CH ₂ ) ₁₂ COOH, C ₄ H ₉ O (C ₂ H ₄ O) ₂ (C
_{H 2) 12 COOH, C 4} H 9 O (C 2 H 4 O) 3 (CH 2) 12
_{COOH, C 12 H 25 O (} C 2 H 4 O) 2 (CH 2) 10 COO
_{H, C 12 H 25 0 (} C 2 H 4 O) 25 (CH 2) 10 COOH,
And the like.

The method for producing the surfactant is not limited at all, but a typical method will be described below.

As shown in the following reaction formula, the halogenated alkyl carboxylic acid is esterified by a conventional method.

[0017]

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(The definitions of R and m are as described above.) The esterification reaction employs well-known alcohol, solvent, catalyst and temperature conditions. On the other hand, as represented by the following reaction formula, an alkyl ether alcohol is converted to an alkoxide by a conventional method using sodium and potassium iodide in a solvent such as toluene, benzene or tetrahydrofuran.

[0019]

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(The definition of n is as described above.) Into the solution containing the alkoxide compound obtained by the above method, the previously obtained ester of the halogenated alkyl carboxylic acid is dropped, and the following reaction is carried out.

[0021]

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The temperature of the reaction is usually in the range of 40 to 150 ° C., and the reaction solvent used when preparing the alkoxide is used as it is. The molar ratio of both reactants used is usually ester / alkoxide = 0.2
To 2.

After the reaction, the reaction solvent is distilled off under reduced pressure, an aqueous NaOH solution is newly added, and the ester bond is hydrolyzed by a conventional method to give a carboxylate compound as shown below.

[0024]

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Next, an aqueous acid solution such as an aqueous HCl solution is added dropwise to the reaction solution until the pH becomes 1, and the carboxylate compound is converted into the carboxylic acid compound intended for the present invention. After the reaction, the mixture is extracted and washed according to a conventional method, and then a crude product is obtained by distilling off an alkyl ether alcohol as a raw material under reduced pressure. By purifying the crude product using a column, a surfactant of a linear aliphatic carboxylic acid, which is a target product, is obtained.

The content of these surfactants is in the range of 2 to 50% by weight based on the magnetic fine particles. If the amount is less than this range, the dispersibility of the magnetic fine particles becomes insufficient.

As the magnetic fine particles used in the present invention, known particles can be employed without limitation. Specifically, Fe, Ni,
Co or alloys thereof, and ferrites such as magnetite, Ba ferrite, Mn ferrite, and Zn ferrite.

The particle size of these magnetic fine particles is preferably 3 to 500 nm, especially 100, in order to uniformly disperse them in a dispersion medium.
nm or less. If it exceeds 500 nm, a magnetic fluid is likely to precipitate, which is not preferable.

The compounding amount of the magnetic fine particles is in the range of 2 to 60% by weight based on the total amount of the magnetic fluid. In a range smaller than this range, it does not behave as a magnetic fluid, and in a range larger than this range, the magnetic fine particles are not stably dispersed.

The polymerizable dispersion medium used in the present invention is not particularly limited as long as it is a polymerizable monomer which is polymerized by a so-called radical reaction, but has a relative dielectric constant of 1.9 to 50 in order to stably disperse the magnetic particles. It is preferable to use a polymerizable dispersion medium in the range of It is particularly preferable to use a polymerizable dispersion medium in the range of 1.9 to 40. When a polymerizable dispersion medium having a relative dielectric constant of more than 50 is used, the magnetic fine particles tend to be difficult to stably disperse.

As an example of the polymerizable dispersion medium having the above-mentioned preferable dielectric constant, a polymerizable monomer having an acryl group and / or a methacryl group may be mentioned. A specific example is as follows.

[Monofunctional monomer] Methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate,
T-butyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl acrylate, cyclohexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, decyl acrylate, isodecyl acrylate,
Dodecyl acrylate, tridecyl acrylate, benzyl acrylate, methoxydiethylene glycol acrylate, 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, glycidyl acrylate and methacrylic esters thereof.

[Bifunctional monomer-aromatic compound system]
2-bis (acryloxyphenyl) propane, 2,2-
Bis [4- (3-acryloxy) -2-hydroxypropoxyphenyl] propane, 2,2-bis (4-acryloxyethoxyphenyl) propane, 2,2-bis (4
-Acryloxydiethoxyphenyl) propane, 2,2
-Bis (4-acryloxytetraethoxyphenyl) propane, 2,2-bis (4-acryloxypentaethoxyphenyl) propane, 2,2-bis (4-acryloxypolyethoxyphenyl) propane, 2,2-bis (4
-Acryloxydipropoxyphenyl) propane, 2
(4-acryloxyethoxyphenyl) -2 (4-acryloxydiethoxyphenyl) propane, 2 (4-acryloxydiethoxyphenyl) -2 (4-acryloxytriethoxyphenyl) propane, 2 (4-acryloxy Dipropoxyphenyl) -2 (4-acryloxytriethoxyphenyl) propane, 2,2-bis (4-acryloxypropoxyphenyl) propane, 2,2-bis (4-acryloxyisopropoxyphenyl) propane, and these Methacrylate.

[Bifunctional monomer-aliphatic compound system]
3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate,
1,10-decanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, butylene glycol diacrylate, glycerin diacrylate, and methacrylic acid esters thereof .

[Tri- or tetra-functional monomers] Trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, trimethylol methane triacrylate, pentaerythritol tetraacrylate, and methacrylic esters thereof.

In addition to the above polymerizable dispersion media, polymerizable monomers generally known for industrial use can be used. Representative examples preferably used include vinyl esters such as vinyl propionate; vinyl ethers such as butyl vinyl ether and isobutyl vinyl ether; styrene;
Alkenylbenzenes such as vinyltoluene, α-methylstyrene, chloromethylstyrene, divinylbenzene, stilbene and the like can be mentioned.

In the present invention, the polymerizable dispersion medium may be used alone or in combination of two or more.

When a plurality of polymerizable dispersion media are used in combination, one of the polymerizable dispersion media has a very high viscosity at room temperature, or when one of the polymerizable dispersion media is a solid, it is used in combination with a low viscosity polymerizable dispersion medium. Is preferred. This combination is not limited to two types, and may be three or more types. Furthermore, if the relative dielectric constant of the entire dispersion medium finally falls within the range of 1.9 to 50, it is also possible to partially mix a non-polymerizable dispersion medium such as ethyl acetate, chloroform, dichloromethane, and acetone. . In the case where the polymerizable magnetic fluid is used for polymerization and curing, the magnetic fine particles are stably dispersed without any problem even if a polymerization initiator is added. The initiator may be added immediately before the polymerization or may be previously contained during the synthesis of the polymerizable magnetic fluid. When added in advance, the polymerization initiator must be stored under conditions that do not cause decomposition of the polymerization initiator (for example, refrigerated under light shielding). In addition, a magnetic fluid containing only one of the two-component polymerization initiator described below is prepared, and
It is also possible to increase the storage stability by mixing at the time of use.

Examples of the polymerization initiator include a thermal polymerization initiator, a redox polymerization initiator, and a photopolymerization initiator.

Specific examples of the thermal polymerization initiator include benzoyl peroxide, di-t-butyl peroxide and t-butyl peroxide.
Organic peroxides such as butyl perbenzoate, 2,2 ′
-Azobisisobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2,4-
Dimethylvaleronitrile), 2,2'-azobis (4-
Methoxy-2,4-dimethylvaleronitrile), 1,
1′-azobis (cyclohexane-1-carbonitrile), dimethyl 2,2′-azobisisobutyrate, 2,2 ′
-Azobis (2-methylpropionic acid), 2,2'-azobis (2-cyclobutylpropionic acid), 2,2'-
Azobis [2- (3-hydroxyphenyl) butyric acid],
2,2′-azobis (4-nitrovaleric acid), 2,2′-
An azo compound such as azobis (4-chlorovaleric acid) is preferably used.

As the redox-based polymerization initiator, a system of the above organic peroxide and a tertiary amine described below can be suitably used. Typical examples of the redox-based polymerization initiator include benzoyl peroxide and N, N-dihydroxyethyl-p-toluidine, or benzoyl peroxide and N, N-dimethyl-p-toluidine.

The photopolymerization initiator is generally used in combination with a photosensitizer and a photopolymerization accelerator. Examples of suitable photosensitizers include benzyl, camphorquinone, α-naphthyl, acetonaphthene, p, p′-.
Α-diketones such as dimethoxybenzyl, p, p′-dichlorobenzyldiacetyl, pentanedione, 1,2-phenanthrenequinone, 1,4-phenanthrenequinone, 3,4-phenanthrenequinone, 9,10-phenanthrenequinone and naphthoquinone It is. These photosensitizers can be used alone or in combination of two or more. Camphorquinone is most preferably used.

Examples of the photopolymerization accelerator include N, N, -dimethylaniline, N, N, -diethylaniline, N, N, -di-n-butylaniline, N, N, -dibenzylaniline, N, N, -Dimethyl-p-toluidine, N, N,-
Diethyl-p-toluidine, N, N, -dimethyl-m-
Toluidine, p-bromo-N, N, -dimethylaniline, m-chloro-N, N, -dimethylaniline, p-dimethylaminobenzaldehyde, p-dimethylaminoacetophenone, p-dimethylaminobenzoic acid, p-dimethylamino Benzoic acid ethyl ester, p-dimethylamino benzoic acid amino ester, N, N-dimethylanthranilic acid methyl ester, N, N, -dihydroxyethylaniline, N, N, -dihydroxyethyl-p-toluidine, p -Dimethylaminophenethyl alcohol, p-dimethylaminostilbene, N, N, -dimethyl-3,5
-Xylidine, 4-dimethylaminopyridine, N, N,
-Dimethyl-α-naphthylamine, N, N, -dimethylβ-naphthylamine, tributylamine, tripropylamine, triethylamine, N-methyldiethanolamine, N-ethyldiethanolamine, N, N, -dimethylhexylamine, N, N,- Dimethyldodecylamine, N, N, -dimethylstearylamine, N, N,-
Tertiary amines such as dimethylaminoethyl methacrylate, N, N, -diethylaminoethyl methacrylate, and 2,2 ′-(n-butylimino) diethanol; 5-butylbarbituric acid, 1-benzyl-5-phenylbarbituric acid Representative examples thereof include barbituric acids. When tertiary amines are used as an accelerator, particularly, N, N, -dihydroxyethyl-p-toluidine, N, N, -dimethyl-p-toluidine, etc. in which an aromatic group is directly substituted with a nitrogen atom. Tertiary amines are more preferably used.

In order to further enhance the photopolymerization accelerating ability, the third
Citric acid, malic acid, tartaric acid, glycolic acid, gluconic acid, α-oxyisobutyric acid, 2-hydroxypropanoic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, dimethylol The addition of oxycarboxylic acids such as propionic acid is effective.

Further, if necessary, an ultraviolet absorber such as 2-hydroxy-4-methylbenzophenone,
Hydroquinone, hydroquinone monomethyl ether,
Phenols such as 2,5-di-t-butyl-4-methylphenol, or phenyl-α-naphthylamine;
A radical polymerization inhibitor such as an aromatic amine such as tetramethyldiaminodiphenylmethane can be similarly added. In addition, as an antioxidant, dilauryl thiodipropionate, which is a sulfur antioxidant, and triphenyl phosphite, which is a phosphorus antioxidant, may be added.

The magnetic fluid of the present invention can be manufactured by a known method. When Fe, Ni, Co or an alloy thereof is used as the magnetic fine particles, a method of thermally decomposing or photodecomposing the carbonyl complex of the metal in the presence of a surfactant may be used.

Fe treated with a surfactant by pyrolysis
An example of a method for producing fine particles is as follows.

Fe ₂ (CO) ₉ or Fe ₃ (CO) ₁₂
A carbonyl complex of Fe, a surfactant, and a dispersion medium (preferably a non-polymerizable dispersion medium having a boiling point of about 90 to 150 ° C.) are mixed in an atmosphere of an inert gas, and the mixed solution is mixed with the complex. By heating above the decomposition temperature of Fe, fine Fe particles are obtained. When Fe (CO) ₅ is used as a raw material, it is preferable to use light irradiation at the time of thermal decomposition. By removing the reaction raw material and the non-polymerizable dispersion medium remaining in the liquid even after the completion of the reaction by distillation, magnetic fine particles having a surfactant adsorbed thereon can be obtained.

Ni Treated with Photolytic Surfactant
An example of a method for producing fine particles is as follows. Using a container made of quartz or the like that can transmit ultraviolet rays, Ni (C
O) ₄ , a surfactant, and a dispersion medium (preferably a non-polymerizable dispersion medium) are mixed under an inert gas atmosphere, and the mixture is irradiated with ultraviolet rays to obtain Ni fine particles. By removing the remaining raw material Ni (CO) ₄ and the non-polymerizable dispersion medium by distillation, magnetic fine particles having a surfactant adsorbed thereon can be obtained.

Next, the obtained particles are mixed with a predetermined polymerizable dispersion medium to obtain a polymerizable magnetic fluid. When obtaining a purified polymerizable magnetic fluid, the magnetic fine particles having poor dispersibility may be removed by centrifugation.

When ferrites such as magnetite, Ba ferrite, Mn ferrite, and Zn ferrite are used as the magnetic fine particles, there is a method of synthesizing a magnetite or a ferrite colloid in an aqueous solution by a coprecipitation method and then treating with a surfactant. .

An example of a method for producing a magnetic fluid in which the magnetic particles are magnetite is as follows.

An aqueous solution comprising a ferrous salt and a ferric salt is reacted with an aqueous alkali solution such as sodium hydroxide to produce fine particles of magnetite. Thereafter, an aqueous solution of a surfactant solubilized by adding an equal amount of an aqueous alkali solution is added to the reaction solution, and the surfactant is adsorbed on the surface of the fine particles by heat treatment. After cooling, an acid is added dropwise to the reaction solution to obtain an acidic aqueous solution. Repeat washing of the precipitate with water to remove excess surfactant and salts. The precipitate is dried under reduced pressure to obtain a powder.

Next, the obtained powder is mixed with a predetermined polymerizable dispersion medium to obtain a polymerizable magnetic fluid. When obtaining a purified polymerizable magnetic fluid, the magnetic fine particles having poor dispersibility may be removed by centrifugation.

[0055]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Production Example 1 Synthesis of Br (CH ₂ ) ₁₀ COOCH ₃ Br (CH ₂ ) ₁₀ COOH 20
0 g, 242 g of methanol, p-CH ₃ C ₆ H ₄ SO ₃ H
· H ₂ O 2.00g, put toluene 400 ml, and heating was continued under reflux for 10 hours. Water from the reaction solution
After removing with O ₄ , toluene and methanol were distilled off under reduced pressure. The product was purified by distillation under reduced pressure to obtain 198 g of a colorless liquid (boiling point 125 ° C./0.3 mmHg).

Production Example 2 H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ C
Synthesis of OOH H (C ₂ H ₄ O) ₃ H was added to a 300 ml two-necked round bottom flask.
40.24 g, 6.67 g of Na, 4.98 g of KI, and 100 ml of toluene were added and heated under reflux for 9 hours. Na
After confirming that all of them have been consumed, Br (CH ₂ ) ₁₀
A solution of 41.9 g of COOCH _{3 in} 50 ml of toluene was added to 7
It was dropped over time. Thereafter, the reaction was terminated by continuing heating and refluxing for another 10 hours.

After toluene was distilled off from the above reaction solution under reduced pressure, 10 g of NaOH and 100 ml of water were added, and the mixture was heated under reflux for 18 hours. After heating under reflux, methanol produced by the reaction was distilled off under reduced pressure. Aqueous hydrochloric acid was added until the pH reached 1. NaCl was added to the reaction until it was saturated. The reaction solution was extracted with chloroform, and the obtained organic phase was washed with saturated saline. After the chloroform was removed under reduced pressure, the raw material H (C ₂ H ₄ O) ₃ H was removed by vacuum distillation. As a crude product, 35.8 g of a brown liquid, which was a residue, was obtained.

20 g of the above crude product was purified by a column. A 11 cm diameter column was packed with Wakogel C-200 to a height of 8 cm. The developing solvent is chloroform /
Methanol (99/1) was used. By-product CH ₂ =
After CH (CH ₂ ) ₈ COOH was eluted, the developing solvent was changed to chloroform / methanol (97/3) to elute the desired purified product. 1 pale brown liquid as purified product
2 g were obtained.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 1.0 to 1.8 ppm
_{(M; 19H, CH 3,} CH 2), 2.34ppm (t;
_{2H, CH 2 COO), 3.3~3.8ppm} (m; 1
2H, CH ₂ OCH _2).

IR: 1110, 1460, 1710, 1
735, 2840, 2920 cm ^{-1 From} these analysis results, the purified product was found to be H (C ₂ H ₄ O) ₃ (C
It was confirmed to have a structure of H ₂ ) ₁₀ COOH.

Example 1 H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ C
Fe ₃ SO ₄ polymerizable magnetic fluid using OOH as a surfactant FeSO ₄ .7H ₂ O and Fe ₂ (SO ₄ ) ₃ under nitrogen
50 ml of a 1 molar aqueous solution of nH ₂ O was mixed, and the pH was adjusted to 11.5 while stirring a 6N aqueous solution of NaOH.
It dripped until it became. This was heated at 70 ° C. for 5 minutes to produce a magnetite colloid. On the other hand, H (C ₂ H
_{4 O) 3 (CH 2)} 10 COOH 4.17g of weighed into another vessel under nitrogen, to which aqueous NaOH 3N 4.3
7 ml and 50 ml of water were added to obtain a homogeneous solution. The above surfactant was added to the magnetite colloid prepared above, and the mixture was kept at 80 ° C. for 30 minutes with stirring. After cooling, a 1N aqueous hydrochloric acid solution was added to the reaction solution to adjust the pH to 5.5, and the colloid was aggregated. The aggregate was washed with water repeatedly to remove the electrolyte, and finally the solid obtained by vacuum filtration was dried at 90 ° C. under reduced pressure for 10 hours. After allowing to cool to room temperature, it was taken out of the dryer. The obtained crude product weighed 12.5 g,
It was a black non-viscous powder.

0.6 g of the obtained crude product was dispersed in 1.4 g of various polymerizable dispersion media shown in Table 1, and this dispersion was dispersed in 80 g
The precipitate was removed from the supernatant by centrifugation under a centrifugal force of 00 G for 20 minutes. Table 1 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. The symbols in Tables 1 to 5 and Table 8 have the following meanings.

[Formation of precipitate] No precipitate was formed after storage at room temperature for 3 months as in the case before storage. × A precipitate was formed during storage at room temperature for 3 months. [State of liquid] A Room temperature After the storage for 3 months, the liquid remained the same as before storage. Z The room temperature solidified during the storage for 3 months. In the magnetic fluid of the present invention, the formation of a precipitate was observed even after the storage for 3 months. And remained liquid without solidification. It was confirmed that the polymerizable magnetic fluid had high storage stability.

[0066]

[Table 1]

Example 2 H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ C
Fe-based polymerizable magnetic fluid using OOH as a surfactant 5.00 g of H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH, 4.00 g of pyridine, and 100 ml of butyl acetate were equipped with a reflux condenser under an argon atmosphere. Weighed into a 1 l separable flask. Fe (CO) ₅ 50.
An additional 0 g was added. Until the generation of carbon monoxide ends,
The mixture was heated and refluxed on a hot plate while performing light irradiation. After cooling, the solvent and the starting materials were distilled off under reduced pressure. Further drying was performed at 90 ° C. under reduced pressure for 10 hours to obtain 14.8 g of a black powder as a crude product.

0.6 g of the obtained crude product was dispersed in 1.4 g of a polymerizable dispersion medium shown in Table 2, and this dispersion was subjected to 8000 dispersion.
The precipitate was removed from the supernatant by centrifugation under the centrifugal force of G for 20 minutes. Table 2 summarizes the formation of precipitates and the change over time in the state of the solution after storage for 3 months at room temperature. In the magnetic fluid of the present invention, formation of a precipitate was not observed even after storage for three months, and the liquid remained liquid without solidification. It was confirmed that the polymerizable magnetic fluid had high storage stability.

[0069]

[Table 2]

Production Example 3 CH ₃ O (C ₂ H ₄ O) ₃ (C
Synthesis of H ₂ ) ₁₀ COOH Instead of H (C ₂ H ₄ O) ₃ H as a raw material, CH ₃ O (C ₂
Production Example 2 except that 79.18 g of H ₄ O) ₃ H was used and tetrahydrofuran was used instead of toluene as a solvent.
Synthesized according to the following procedure. As a crude product, 40.5 g of a brown liquid as a residue was obtained. 15 g of the above crude product was purified by a column. As a purified product, 5.0 g of a light brown liquid was obtained.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 1.1 to 1.8 ppm
_{(M; 16H, CH 2)} , 2.34ppm (t; 2H,
_{CH 2 COO), 3.2~3.8ppm (m} ; 17H,
_{CH 3 O, CH 2 OCH 2} ).

IR: 1110, 1465, 1710, 1
735, 2860, 2930 cm ^{-1 From} these analysis results, purified product was CH ₃ O (C ₂ H ₄ O) ₃
It was confirmed to have a structure of (CH ₂ ) ₁₀ COOH.

Example 3 CH ₃ O (C ₂ H ₄ O) ₃ (C
Fe ₃ SO ₄ -based polymerizable magnetic fluid using H ₂ ) ₁₀ COOH as a surfactant FeSO ₄ .7H ₂ O and Fe ₂ (SO ₄ ) ₃ under nitrogen
50 ml of a 1 molar aqueous solution of nH ₂ O was mixed, and the pH was adjusted to 11.5 while stirring a 6N aqueous solution of NaOH.
It dripped until it became. This was heated at 70 ° C. for 5 minutes to produce a magnetite colloid. On the other hand, CH ₃ O (C ₂
4.57 g of H ₄ O) ₃ (CH ₂ ) ₁₀ COOH were weighed out in a separate container under nitrogen, and 3N aqueous NaOH solution was added thereto.
37 ml and 50 ml of water were added to make a homogeneous solution. The above surfactant was added to the magnetite colloid prepared above, and the mixture was kept at 80 ° C. for 30 minutes with stirring. After cooling, a 1N aqueous hydrochloric acid solution was added to the reaction solution to adjust the pH to 5.5, and the colloid was aggregated. The reaction solution was separated into a precipitate and a supernatant by centrifugation at 1,500 g. The precipitate was dried at 90 ° C. under reduced pressure for 10 hours. After allowing to cool to room temperature, it was taken out of the dryer. The crude product obtained was 15.0 g,
It was a black, slightly viscous powder.

0.6 g of the obtained crude product was dispersed in 1.4 g of a polymerizable dispersion medium shown in Table 3, and this dispersion was subjected to 8000 dispersion.
The precipitate was removed from the supernatant by centrifugation under the centrifugal force of G for 20 minutes. Table 3 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. In the magnetic fluid of the present invention, formation of a precipitate was not observed even after storage for three months, and the liquid remained liquid without solidification. It was confirmed that the polymerizable magnetic fluid had high storage stability.

[0076]

[Table 3]

Production Example 4 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₂₅ (C
Synthesis of H ₂ ) ₁₀ COOH Instead of H (C ₂ H ₄ O) ₃ H as a raw material, C ₁₂ H ₂₅ O
It was synthesized according to Production Example 2 except that 390 g of (C ₂ H ₄₀ ) ₂₅ H was used. As a crude product, 420 g of a brown liquid, which is a residue, was obtained. 20 g of the above crude product was purified by a column. 5g of pale brown liquid as purified product
Obtained.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 0.89 ppm (t; 3
_{H, CH 3), 1.1~1.8ppm (} m; 36H, C
_{H 2), 2.34ppm (t;} 2H, CH 2 COO),
_{3.3~3.8ppm (m; 104H, CH 2} OC
H _2).

IR: 1110, 1460, 1710, 1
735, 2840, 2920 cm ^{-1 From} these analysis results, the purified product was found to be C ₁₂ H ₂₅ O (C ₂ H
₄ O) have a ₂₅ (CH ₂₎ a ₁₀ COOH structure was confirmed.

Example 4 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₂₅ (C
Instead of H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH which is a raw material of Fe ₃ SO ₄ polymerizable magnetic fluid using H ₂ ) ₁₀ COOH as a surfactant, C ₁₂ H ₂₅ O (C ₂ H) ₄ O) ₂₅ (CH ₂ ) ₁₀ COOH
It prepared according to Example 1 except having used 19.3 g. The obtained crude product weighed 26.5 g and was a black viscous powder.

0.6 g of the obtained crude product was dispersed in 1.4 g of a polymerizable dispersion medium shown in Table 4, and this dispersion was subjected to 8000 dispersion.
The precipitate was removed from the supernatant by centrifugation under the centrifugal force of G for 20 minutes. Table 4 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. In the magnetic fluid of the present invention, formation of a precipitate was not observed even after storage for three months, and the liquid remained liquid without solidification. It was confirmed that the polymerizable magnetic fluid had high storage stability.

[0083]

[Table 4]

Production Example 5 Synthesis of Br (CH ₂ ) ₁₂ COOCH ₃ Instead of Br (CH ₂ ) ₁₀ COOH as a raw material, Br
Synthesized according to Production Example 1 except that (CH ₂ ) ₁₂ COOH was used. 190 g of a colorless liquid was obtained as the product (boiling point 142 ° C./0.2 mmHg).

Production Example 6 H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₂ C
Synthesis of OOH Instead of Br (CH ₂ ) ₁₀ COOCH _{3 as} a raw material, Br
It was synthesized according to Production Example 2 except that 45.8 g of (CH ₂ ) ₁₂ COOCH ₃ was used. As a crude product, 33.7 g of a brown liquid, which was a residue, was obtained.

20 g of the above crude product was purified by a column. A 11 cm diameter column was packed with Wakogel C-200 to a height of 8 cm. The developing solvent is chloroform /
Methanol (99/1) was used. By-product CH ₂ =
After CH (CH ₂ ) ₁₀ COOH was eluted, the developing solvent was changed to chloroform / methanol (97/3) to elute the desired purified product. As a purified product, 10 g of a light brown liquid was obtained.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 1.0 to 1.8 ppm
_{(M; 23H, CH 3,} CH 2), 2.34ppm (t;
_{2H, CH 2 COO), 3.3~3.8ppm} (m; 1
2H, CH ₂ OCH _2).

IR: 1110, 1460, 1710, 1
735, 2840, 2920 cm ^{-1 From} these analysis results, the purified product was found to be H (C ₂ H ₄ O) ₃ (C
It was confirmed to have a structure of H ₂ ) ₁₂ COOH.

Example 5 H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₂ C
H (C ₂ H ₄ O) ₃ (CH ₂ ) instead of H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH which is a raw material of a Fe ₃ SO ₄ polymerizable magnetic fluid using OOH as a surfactant ₁₂ COOH 4.50g
Was prepared according to Example 1 except that was used. The obtained crude product weighed 12.3 g and was a black viscous powder.

0.6 g of the obtained crude product was dispersed in 1.4 g of various polymerizable dispersion media shown in Table 5, and this dispersion was dispersed in 80 g
The precipitate was removed from the supernatant by centrifugation under a centrifugal force of 00 G for 20 minutes. Table 5 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. In the magnetic fluid of the present invention, formation of a precipitate was not observed even after storage for three months, and the liquid remained liquid without solidification. It was confirmed that the polymerizable magnetic fluid had high storage stability.

[0092]

[Table 5]

Example 6 Thermal Polymerization of Polymerizable Magnetic Fluid In the same manner as in Example 1, 0.4 g of a polymerizable magnetic fluid obtained from magnetite, a surfactant and a polymerizable dispersion medium shown in Table 6 was added to Table 6 Was added, and the inside of the container was set to a nitrogen atmosphere. Thermal polymerization was performed under the conditions shown in Table 6. The symbols in Tables 6 and 7 have the following meanings.

The polymerizable magnetic fluid was solidified. × The polymerizable magnetic fluid did not completely solidify and had fluidity. All the polymerizable magnetic fluids obtained in this example were solidified.

[0095]

[Table 6]

Example 7 Photopolymerization of Polymerizable Magnetic Fluid In the same manner as in Example 1, 0.4 g of the polymerizable magnetic fluid obtained from magnetite and the surfactant and the polymerizable dispersion medium shown in Table 7 was added to Table 7 The photopolymerization initiator (photosensitizer 0.
001 g and a photopolymerization accelerator 0.001 g) were added, and a part of the solution was sandwiched between glass plates. The illuminance on the glass surface was 50,000 using an optical fiber cold light illuminator.
Ix light was applied for the time shown in Table 7. All of the polymerizable magnetic fluid obtained in the present invention solidified, and the glass plate did not move.

[0097]

[Table 7]

Comparative Example 1 7.3 g of linoleic acid was used instead of H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH which is a raw material of Fe ₃ SO ₄ polymerizable magnetic fluid using linoleic acid as a surfactant. 3N NaOH aqueous solution 8.8
It was prepared according to Example 1 except that a solution to which ml was added was used. The obtained crude product was 14.8 g and was a black viscous powder.

0.6 g of the obtained crude product was dispersed in 1.4 g of various polymerizable dispersing media shown in Table 8, and this dispersion was
The precipitate was removed from the supernatant by centrifugation under a centrifugal force of 00 G for 20 minutes. Table 8 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. It was confirmed that the magnetic fluid of the comparative example did not change with time in the monofunctional monomer, but the precipitate formed and solidified in the polyfunctional monomer, and clearly changed with time.

[0100]

[Table 8]

Comparative Example 2 H (C ₂ H ₄ O) ₂ (CH ₂ ) ₈ C
A Fe ₃ SO ₄ polymerizable ferrofluid raw material with the surfactant and _{OOH H (C 2 H 4 O} ) 3 (CH 2) H (C 2 H 4 O) in place of ₁₀ COOH ₂ (CH _{2) A} magnetic fluid was prepared in the same manner as in Example 1 except that ₈ COOH was used. Table 9 summarizes the formation of precipitates and the change over time in the state of the solution after storage at room temperature for 3 months. It was confirmed that the magnetic fluid did not change over time in the monofunctional monomer, but the precipitate formed and solidified in the polyfunctional monomer, and clearly changed over time.

[0102]

[Table 9]

The surfactant used in this comparative example was synthesized as follows.

Synthesis of Br (CH ₂ ) ₈ COOCH ₃ Instead of Br (CH ₂ ) ₁₀ COOH as a raw material, Br
Synthesized according to Example 1 except that (CH ₂ ) ₈ COOH was used. 193 g of a colorless liquid was obtained as the product (boiling point 108 ° C./0.8 mmHg).

Synthesis of H (C ₂ H ₄ O) ₂ (CH ₂ ) ₈ COOH Instead of H (C ₂ H ₄ O) ₃ H which is a raw material, H (C ₂ H)
₄ O) using _{2 H 27.0g, Br (CH 2} ) 10 COO
Br (CH ₂ ) ₈ COOCH ₃ 37.7 instead of CH ₃
Synthesized according to Example 1 except that g was used. As a crude product, 20.0 g of a brownish liquid as a residue was obtained.

15 g of the above crude product was purified by a column. As a purified product, 10 g of a light brown liquid was obtained.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 1.0 to 1.8 ppm
_{(M; 15H, CH 3,} CH 2), 2.34ppm (t;
_{2H, CH 2 COO), 3.3~3.8ppm} (m; 8
H, CH ₂ OCH _2).

IR: 1110, 1460, 1710, 1
735, 2840, 2920 cm ^{-1 From} these analysis results, the purified product was found to be H (C ₂ H ₄ O) ₂ (C
It was confirmed to have a structure of H ₂ ) ₈ COOH.

Comparative Example 3 HO (C ₂ H ₄ O) ₂ (CH ₂ ) ₁₀
Instead of H (C ₂ H ₄ O) ₃ (CH ₂ ) ₁₀ COOH which is a raw material of Fe ₃ SO ₄ polymerizable magnetic fluid using COOH as a surfactant, HO (C ₂ H ₄ O) ₂ (CH ₂ ) An attempt was made to prepare a magnetic fluid in the same manner as in Example 1 except that ₁₀ COOH was used.
No magnetic particles were dispersed in the monomer, and no magnetic fluid was obtained. The surfactant used in this comparative example was synthesized as follows.

HO (C ₂ H ₄ O) ₂ H was replaced with 340 g of H (C ₂ H ₄ O) ₃ H, and the synthesis was carried out according to Example 1 except that toluene was not used. As a crude product, 53.3 g of a brown liquid as a residue was obtained.

43 g of the above crude product was dissolved in 43 m of methanol.
and left at −20 ° C. overnight. The precipitated crystals were filtered and dried to obtain 7.2 g of a solid as a purified product.

1H-NMR of the purified product (CDCl ₃ , T
MS is used as a reference (0.00 ppm). ) And IR analysis gave the following results.

1H-NMR: 1.1 to 1.8 ppm
_{(M; 18H, CH 2)} , 2.34ppm (t; 2H,
_{CH 2 COO), 3.3~3.9ppm (m} ; 11H,
CH ₂ OCH _2, HOC).

IR: 1110, 1465, 1720, 1
735, 2860, 2910, 3450 cm ^{-1 From} these analysis results, the purified product was found to be HO (C ₂ H ₄ O)
It was confirmed to have a structure of ₂ (CH ₂ ) ₁₀ COOH.

[0116]

According to the polymerizable magnetic fluid obtained by the present invention, magnetic fine particles are dispersed in an extremely stable state without forming a precipitate during storage. Further, it has the feature that it does not undergo polymerization during storage and cures only at the time of polymerization, and is extremely useful industrially.

Claims (2)

(57) [Claims] (A) a compound represented by the general formula: (However, R represents an alkyl group having 1 to 12 carbon atoms, and n represents 1 to
A polymerizable magnetic fluid comprising: a surfactant represented by the formula (25), m represents an integer of 10 to 12), (b) magnetic fine particles, and (c) a polymerizable dispersion medium. (A) a general formula: (However, R represents an alkyl group having 1 to 12 carbon atoms, and n represents 1 to
25, and m represents an integer of 10 to 12), (b) magnetic fine particles, (c) a polymerizable dispersion medium, and (d) a polymerization initiator. Polymerizable magnetic fluid.