JP2001335804A - Silver colloid substance and silver colloid associated body substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new silver colloid substance and the associated body substance thereof. SOLUTION: Silver nanograins are coated, via the bonding of a specified sulfur-containing fluorocarbon-based compound (fluorinated alkylmercaptan, fluorinated alkyldisulfide or the ester of the fluorinated alkyl and thioacetic acid) and sulfur atoms, with the molecules thereof to form a silver colloidal substance. The above silver colloid substances are further mutually associated by the action of the residual molecules of the above specified sulfur-containing fluorocarbon-based compound to form a silver colloid associated body substance. The silver colloid substance has a yellow color, the silver colloid associated body substance has originally an orange color or a red color, and, for example, use for coloring agents is expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel silver colloidal substance and an associated substance thereof, and more particularly to a yellow silver colloidal substance and an orange to red colloidal silver associated substance.

[0002]

2. Description of the Related Art In recent years, color development by precious metal colloids has attracted attention, and its application as a colorant or the like has been studied (JP-A-11-80647, JP-A-11-319538).
No.). This coloring is due to a coloring mechanism called plasmon absorption caused by the plasma oscillation of electrons, and free electrons in the metal are shaken by the photoelectric field to cause charges to appear on the surface of the metal particles and nonlinear polarization to occur. It has been. This coloration occurs when the particle size of the noble metal particles is several nm.
It is found in nanoparticles of about to several tens of nm, has high chroma and light transmittance, and is excellent in durability and the like. JP-A-11-80647, JP-A-11-31
The noble metal colloid disclosed in Japanese Patent No. 9538 is a dispersion of noble metal nanoparticles using a polymer pigment dispersant as a protective colloid, and the color of gold is red and the color of silver is yellow and the color of its color is limited. It was done.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel silver colloid substance and an associated substance thereof.

[0004]

According to the present invention, there is provided a method for producing a silver nanoparticle comprising the following chemical formula (1), (2) or (3): CF _3- (CF ₂ ) _m- (CH ₂ ) _n -SH (1) _{CF 3 - (CF 2) p} - (CH 2) q -SS- (CH 2) r - (CF 2) s -CH 3 (2) CF 3 - (CF 2) x - (CH 2) y -S —CO—CH ₃ (3) [where m, p, s and x independently represent an integer of 5 to 13, and n, q, r and y independently represent an integer of 1 to 5]. A silver colloidal material characterized by being coated with a sulfur atom of a sulfur-containing fluorine-containing compound through a bond with a sulfur atom of the compound, and the silver colloidal material described above,
An object of the present invention is to provide a silver colloid-associated substance which is further associated with each other by the action of an extra molecule of the sulfur-containing fluorocarbon compound represented by the above chemical formula (1), (2) or (3).

The sulfur-containing fluorinated carbon compound represented by the chemical formula (1) is a fluorinated alkyl mercaptan,
Is a fluorinated alkyl disulfide (fluorinated alkyl disulfide), and the sulfur-containing fluorocarbon compound of formula (3) is fluorinated alkyl esters of thioacetic acid. These can be used alone or in combination.

In the colloidal silver material of the present invention, it is preferable that the surface silver atoms of the silver nanoparticles and the sulfur atom of the sulfur-containing fluorine-containing compound represented by the above formula (1), (2) or (3) are covalently bonded. [For example, Toshihiro Kondo, Kohei Uozaki,
“Utilization of Gold-Sulfur Bond: Self-Assembled Monolayer (SA)
M) ", Chemistry and Industry, Vol. 52, No. 7 (1999), pp. 842-847], and the sulfur-containing fluorocarbon compound acts as an extremely stable protective colloid. FIG.
FIG. 2 is a model diagram of the silver colloidal substance of the present invention, and FIG. 2 is a three-dimensional model diagram of a sulfur-containing fluorocarbon compound (perfluorooctylethyl mercaptan) when m = 7 and n = 2 in the chemical formula (1). is there. In the silver colloid material of the present invention, the sulfur-containing fluorine-containing compound is bonded to the silver nanoparticles via sulfur, and the fluorine atom bonded to the alkyl fluoride group is much larger than the hydrogen atom. In the fluorine chain, the rotation of the CC bond is prevented, so that the fluorocarbon group has an extended chain structure. Further, since the fluorine atoms themselves are helically positioned in the extended chain structure, the silver nanoparticles coated with the sulfur-containing fluorine-containing carbon-based compound can be considered as hard spheres like sea urchins. Such a colloidal silver material has a plasmon absorption wavelength of 400
It is concentrated around the peak around nm and therefore exhibits a yellow color. In addition, the silver colloid material of the present invention is coated with silver nanoparticles containing a sulfur-containing fluorine-based compound having excellent properties such as weather resistance, chemical resistance, and heat resistance.
Excellent in the above properties.

[0007] The silver colloid-associated substance of the present invention is
Formula (1), (2) or (3) of a sulfur-containing fluorocarbon system
It is a substance that is produced when the compound is present in excess. this
In the case, the sulfur-containing fluorocarbon compound is a silver colloid substance
Usually, it is used in excess during the synthesis of
Or from a synthetic phase, for example, in a fluorine-based solvent.
After purification by causing phase transfer of
You may add together with a polar solvent. This silver colloid society
In the coalesced substance, outside the above-mentioned aggregate of the silver colloidal substance
Alkyl fluorinated groups such as sea urchin spines in lateral colloidal substances
Fluorination of extra sulfur-containing fluorocarbon molecules in gaps
Alkyl chains partially enter due to their strong affinity
Including those SH groups, SS groups and S-CO-CH₃Out of the group
Of the excess sulfur-containing fluorocarbon compound in a form
A considerable amount of silver colloidal material is generated by strong affinity between molecules.
Meeting with the stability of FIG. 3 shows such a silver coin.
A model showing the fibrous association state of the Lloyd associate material
FIG. 4 is a diagram showing a small circle representing a silver colloidal substance.
3 is an enlarged model diagram around a large circle, where the large circle is silver
The rectangle represents a colloidal substance, and the rectangle is CF of chemical formula (1).₃-
(CF₂)_m-(CH₂) _n-Represents the part, the small circle is the chemical formula
Represents the -SH portion of (1). In this meeting state,
A tube-like type of extra sulfur-containing fluorocarbon compound
The micelles are filled with a silver colloidal substance.
Thus, SH group, SS group, S-CO-CH₃Group outside
Extra sulfur-containing fluorocarbon compounds are arranged in a line
To achieve this, the SH group, SS group, S-CO-CH₃Group and
The presence of a polar medium with some affinity is required. Silver
The fact that the colloid spontaneously forms the above aggregates
More specifically, by the dense aggregation of silver nanoparticles,
The plasmon absorption shifts to a longer wavelength, so that 500n
The presence ratio of absorption wavelengths exceeding m increases and redness increases.
It is considered that the silver colloid-associated substance changes its color from orange to red.
It is usually present. Further, the silver colloid association of the present invention
Body material has excellent properties such as weather resistance, chemical resistance, heat resistance, etc.
Silver nanoparticles are coated with a sulfur-containing fluorocarbon compound
And have been meeting further,
It is cheaper than red gold colloid.

The average particle size of the silver nanoparticles is 1 to several tens of nm.
It is preferably in the range of about 2 to about 10 nm in terms of color, and particularly preferably in the range of about 2 to about 5 nm.

[0009]

Next, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

The silver colloid substance or the silver colloid-associated substance of the present invention is prepared by dissolving a silver compound soluble in a polar solvent such as silver acetate, silver nitrate, silver perchlorate and the like, and stirring the mixture with the above chemical formula (1). ), (2) or (3), which can be prepared by adding a sulfur-containing fluorocarbon compound and performing a reduction reaction with vigorous stirring. As the silver compound, silver perchlorate which is easily soluble in a polar solvent is particularly preferred. The reduction reaction is, for example,
It can be performed by a method of irradiating light with a high-pressure mercury lamp or a method of adding a reducing agent. As the reducing agent, for example,
Alkali metal borohydrides such as sodium borohydride, ammonium borohydrides, hydrazine compounds, dimethylaminoethanol, dimethylethylamine, N, N, N ', N'-tetramethyl-1,3-diaminopropane And the like.

The polar solvent is capable of dissolving both the sulfur-containing fluorine-containing compound represented by the above formula (1), (2) or (3) and the silver compound. Examples of the polar solvent include methanol, ethanol, isopropanol, and the like. alcohol solvents such as s-butanol, n-butanol, n-hexanol, 2-ethylhexanol and butyl cellosolve; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate; tetrahydrofuran Ether solvents and the like. These can be used alone or as a mixture, and can also be used as a mixture with non-polar solvents. Tetrahydrofuran and ethyl acetate are particularly preferred.

FIG. 5 is a diagram showing a plasmon absorption spectrum of a silver colloid substance or a silver colloid-associated substance produced in Examples 1 and 2 described later. The absorbance “Absorbance” in FIG. 5 is an arbitrary unit, and “S /
The “Ag ratio” is a molar ratio of perfluorooctylethyl mercaptan / silver perchlorate as a raw material used for producing a silver colloidal substance or a silver colloid associate substance. It can be seen that the higher the S / Ag ratio, the higher the absorption intensity at an absorption wavelength of 500 nm or more. FIG. 6 is a graph showing the relationship between the S / Ag ratio of the plasmon absorption spectrum and the maximum absorption wavelength (λmax) of the silver colloid material or the silver colloid-associated material produced in Examples 1 and 2 described below.
This shows that the higher the / Ag ratio, the longer the maximum absorption wavelength shifts to the longer wavelength side, and accordingly, the color of the substance of the present invention becomes reddish. That is, it can be seen that redness increases as the S / Ag ratio increases and association of silver colloid progresses. The association of the silver colloid forms a fibrous or spherical aggregate depending on the conditions.

The silver compound undergoes a reduction reaction to form silver nanoparticles, and the surface silver atoms of the silver nanoparticles react with the sulfur-containing fluorine-containing carbon compound of formula (1), (2) or (3). Since it is considered that a covalent bond is formed, the sulfur-containing fluorocarbon compound acts as a strong protective colloid, and can make the silver colloid extremely stable. The silver colloid material thus stabilized is, for example,
Stably dispersed in various polymers using organic solvent-soluble fluorine-based polymers (for example, copolymers of fluorine-containing monomers and other general monomers) and, if necessary, a dispersant. Can be done. For example, a silver colloidal substance solution produced in a polar solvent and an organic solvent solution of various polymers are mixed, and a dispersant is used in combination as necessary, to obtain a stable yellow paint or printing ink of the silver colloidal substance. Obtainable. In the silver colloidal substance, since the sulfur-containing fluorocarbon compound serving as a protective colloid is held by silver nanoparticles with a very strong bond, the formed silver colloidal substance is once dried, and then the chlorofluorocarbons, fluorocarbons, etc. It is expected that it can be dispersed in a fluorine-based solvent and can be dispersed in an organic solvent solution such as a fluorine-based polymer. In such a case, it is expected that toning is possible by dispersing other color pigments, white pigments, and extender pigments as necessary.

On the other hand, in order for the silver colloidal substance to form an associated substance, for example, the sulfur-containing carbonized compound represented by the chemical formula (1), (2) or (3) is added to the reaction system so as to increase the S / Ag ratio. What is necessary is just to add a fluorine compound. The resulting silver colloid-associated substance has a mercapto group (-SH), a disulfide group (-SS-), and a methylthiocarboxylic acid group (-SC) on the surface.
Since it has a polar group of O-CH ₃ ), it is quite stable in the polar solvents listed above, and a solution of this colloidal silver aggregate in a polar solvent and an organic solvent solution of various polymers are mixed to give an orange color. Or a red paint or a printing ink. If other color pigments, white pigments, or extender pigments are also required, lightly mix the polar solvent solution of the silver colloid-associated substance with the dispersion obtained by kneading these with the organic solvent solution of the polymer, and toning is possible. Is expected.

[0015]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A 100 ml round bottom flask was charged with 30 ml of a 5 mmol solution of silver perchlorate (AgClO ₄ ) in ethanol. While stirring, add perfluorooctylethyl mercaptan [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ S at room temperature to this solution.
H] was added so that the S / Ag ratio was 1.0. At this time, no precipitation occurred in the reaction system, but it became slightly cloudy.

Then, while stirring vigorously, immediately
5 ml of water in which 74 g (2 mmol) of sodium borohydride was dissolved was slowly added dropwise in a fixed amount. The reaction system turned black-red.

After completion of the dropwise addition, stirring was continued for about 3 hours. Immediately after the preparation, almost no precipitate and the like were observed, and the dispersion was a uniform silver nanoparticle aggregate. However, precipitation occurred after several days. When the silver nanoparticle aggregate was observed with a transmission electron microscope, it was confirmed that the aggregate was a fiber-like aggregate having an average aspect ratio of about 133.

Example 2 The same operation as in Example 1 was performed except that the amount of perfluorooctylethyl mercaptan was changed so as to change the S / Ag ratio. The plasmon absorption spectrum of each product was measured to obtain FIGS. 5 and 6.

[0020]

The silver colloid material of the present invention is characterized in that the surface silver atoms of silver nanoparticles are covalently bonded to the sulfur atoms of the sulfur-containing fluorocarbon compound of formula (1), (2) or (3). It is considered a very stable yellow colloidal substance. In addition, the silver colloid-associated substance of the present invention is a substance generated when an excess of the sulfur-containing fluorocarbon compound represented by the chemical formula (1), (2) or (3) is present. Extra alkyl fluoride chains of the sulfur-containing fluorocarbon compound molecules partially enter into the gaps between the alkyl fluoride groups, such as sea urchin spines, of the colloidal substance on the outer side of the aggregate due to their strong affinity. SH group or SS
Since bringing into association silver colloidal material in the form of arranging the groups or S-CO-CH ₃ group outside the strong affinity of molecules with each of the sulfur-containing fluorocarbon-based compounds, is fairly stable normal kai orange to red It is a united substance.

The substance of the present invention is chemically stable and, when used as a coloring agent, can impart a vivid color to the obtained coating film, printed film or molded product. For example, a colorant such as a normal yellow or orange to red pigment or the like expresses such a color by reflected light, whereas the silver colloid substance and the silver colloid aggregate substance of the present invention have a yellow or orange or It develops red color. The substance of the present invention includes various paints, printing inks, colorants for liquid crystal color filters,
It is expected that it can be used for applications such as optical materials, catalysts, carriers for antibodies, and other applications different from conventional silver colloids.

[Brief description of the drawings]

FIG. 1 is a model diagram of a silver colloid substance of the present invention.

FIG. 2 is a graph showing that m = 7 and n = 2 in the chemical formula (1).
FIG. 3 is a three-dimensional model diagram of a sulfur-containing fluorine-containing compound in the case of FIG.

FIG. 3 is a model diagram showing a part of a fibrous association state of a silver colloid-associated substance of the present invention.

FIG. 4 is an enlarged model diagram around a large circle in FIG. 3;

FIG. 5 is a view showing a plasmon absorption spectrum of the silver colloid substance or silver colloid-associated substance produced in Examples 1 and 2.

FIG. 6 is a graph showing the relationship between the S / Ag ratio of the plasmon absorption spectrum of the silver colloidal substance and the silver colloid-associated substance produced in Examples 1 and 2, and the maximum absorption wavelength (λmax).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B22F 9/00 B22F 9/00 B (72) Inventor Shinya Onoe 14-11 Omino, Kokuraminami-ku, Kitakyushu-shi, Fukuoka Prefecture F term (reference) 4G065 AA04 AB21Y AB29Y BA13 BB06 CA13 DA06 DA09 EA03 4J037 AA04 CB01 CB21 DD05 DD23 EE03 EE28 EE43 FF06 FF07 4K017 AA08 BA02 CA08 DA07 DA09 EJ01 FB07 4K018 BA04 BB05 BC30 BD

Claims (2)

[Claims] The silver nanoparticles have the following chemical formula (1):
(2) or (3) CF _3- (CF ₂ ) _m- (CH ₂ ) _n -SH (1) CF _3- (CF ₂ ) _p- (CH ₂ ) _q -SS- (CH ₂ ) _r- ( CF ₂ ) _s -CH ₃ (2) CF _3- (CF ₂ ) _x- (CH ₂ ) _y -S-CO-CH ₃ (3) wherein m, p, s and x are independently 5 to 13 And n, q, r and y each independently represent an integer of 1 to 5], and the sulfur-containing fluorocarbon compound represented by the following formula: A silver colloid substance characterized by the following. 2. The action of an extra molecule of the sulfur-containing fluorocarbon compound represented by the chemical formula (1), (2) or (3) according to claim 1 wherein the silver colloidal substance according to claim 1 is used. And a silver colloid associated substance further associated with each other.