JP2009007616A - Method for producing silica-coated gold colloidal particle, and silica-coated gold colloidal particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silica-coated gold colloidal particle which is not flocculated or discolored even when heating treatment is applied, and capable of maintaining clear red. <P>SOLUTION: Disclosed is a method for producing a silica-coated gold colloidal particle characterized in that a gold colloidal particle (M)-dispersed liquid in which the average particle diameter lies in the range of 5 to 100 nm, and subjected to surface treatment with a carboxyl group and/or carboxylate group-containing organic compound and a silica colloidal particle (A)-dispersed liquid in which the average particle diameter lies in the range of 4 to 40 nm, and subjected to surface treatment with an amino group-containing silane compound are mixed. Also disclosed is a method for producing a silica-coated gold colloidal particle characterized in that a gold colloidal particle (M)-dispersed liquid in which the average particle diameter lies in the range of 5 to 100 nm and a silica colloidal particle (A)-dispersed liquid in which the average particle diameter lies in the range of 4 to 40 nm, and subjected to surface treatment with a mercapto group-containing silane compound, and into which a thiol group(-SH group) is introduced are mixed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel silica-coated gold colloidal particle and a method for producing the same.

  Conventionally, gold particles are used for conductive materials, electronic component materials, catalysts, biomarkers, etc., and since they are red when colloidal particles are used, they are also used as phosphor pigments, cosmetic materials, etc. Yes.

  However, when gold colloid particles are used as a pigment in a high-temperature environment, specifically, when used in a cathode ray tube or the like, there is a problem that the temperature becomes about 400 ° C. and easily aggregates or turns black.

  Accordingly, various attempts have been made to modify the surface of colloidal gold. In order to stabilize the surface, the present inventors tried to coat gold colloid particles with a silica layer, but when heat treatment was performed to stabilize the silica coating layer, the gold colloid particles became It was difficult to obtain the desired product by agglomeration or discoloration.

  Under such circumstances, the advent of a method for forming a silica coating layer on the surface of colloidal gold particles has been desired.

In order to solve the above problems, the present inventors have intensively studied the method of coating the silica layer. As a result, the surface treatment of the colloidal silica particles and the colloidal gold particles can be applied to the surface of the colloidal metal particles by a specific combination. Particles in which silica colloidal particles are combined in layers are obtained, and the present invention has been completed by finding that a vivid red color can be maintained without agglomeration or discoloration even when heat-treated.
[1] A colloidal gold particle dispersion having an average particle diameter in the range of 5 to 100 nm and surface-treated with a carboxyl group and / or carboxylate group-containing organic compound;
A method for producing silica-coated gold colloidal particles, comprising mixing a silica colloidal particle dispersion having an average particle diameter in the range of 4 to 40 nm and surface-treated with an amino group-containing silane compound.
[2] a colloidal gold particle dispersion having an average particle size in the range of 5 to 100 nm;
A method for producing silica-coated gold colloidal particles comprising mixing a silica colloidal particle dispersion having an average particle diameter in the range of 4 to 40 nm and surface-treated with a mercapto group-containing silane compound and introduced with thiol groups (-SH groups) .
[3] The method for producing a silica-coated gold colloidal particle according to [1] or [2], wherein after mixing the dispersion, an acidic silicic acid solution is further added to coat the surface of the silica colloidal particle.
[4] The method for producing a silica-coated gold colloidal particle according to [1] to [3], which is further dried and / or heat-treated.
[5] Silica colloidal particles having an average particle size in the range of 4 to 40 nm and an average particle size of 5 to 10
Silica-coated gold colloidal particles obtained by coating the surface of colloidal gold particles in the range of 0 nm.
[6] The silica-coated gold colloidal particles according to [5], further formed with a silica coating layer.
[7] The silica-coated gold colloidal particles according to [5] or [6], wherein the thickness of the silica layer (the total of the silica colloid particle layer and the silica coating layer formed as necessary) is in the range of 4 to 50 nm.
[8] The silica-coated gold colloidal particles exhibit a red color (wavelength: 520 to 550 nm) [5] to [7]
Silica-coated gold colloidal particles.

  According to the present invention, since the surface of the gold colloid particles is entirely coated with the silica colloid particles, it does not agglomerate or deform even when exposed to a high temperature, and exhibits a clear red color without further discoloration. A method for producing gold colloidal particles and silica-coated gold colloidal particles obtained by the production method can be provided.

Hereinafter, the present invention will be specifically described.
[Method for producing silica-coated gold colloidal particles]
The first production method of the silica-coated gold colloidal particles according to the present invention includes:
A colloidal gold colloidal particle (M-1) dispersion having an average particle size in the range of 5 to 100 nm and surface-treated with a carboxyl group and / or carboxylate group-containing organic compound;
The average particle diameter is in the range of 4 to 40 nm and is characterized by mixing with a silica colloidal particle (A-1) dispersion liquid surface-treated with an amino group-containing silane compound.

Further, the second production method of the silica-coated gold colloidal particles according to the present invention includes:
A colloidal gold particle (M-2) dispersion having an average particle size in the range of 5 to 100 nm;
Mixing with a silica colloidal particle (A-2) dispersion having an average particle diameter in the range of 4 to 40 nm and having a thiol group (-SH group) on the surface treated with a mercaptoto group-containing silane compound. It is a feature.

Colloidal gold particles As the gold colloid particles (M), conventionally known gold colloid particles can be used.
The colloidal gold particles preferably have an average particle diameter (D _M ) of 5 to 100 nm, more preferably 10 to 50 nm.

When the average particle diameter (D _M ) of the colloidal gold particles is less than 5 nm, when used as a red pigment, the red color tone is impaired, and it is difficult to coat with the colloidal silica particles. If D _M ) exceeds 100 nm, it is not suitable as a red pigment.

When used as a red pigment, the average particle size is preferably 50 nm or less, particularly 40 nm or less.
Such gold colloidal particles (M) can be produced by a conventionally known method. For example, it can be produced by a known method of reducing an aqueous chloroauric acid solution in the presence of a reducing agent. Or it can obtain also by irradiating a chloroauric acid aqueous solution with an ultrasonic wave.

The gold colloidal particles (M-1) used in the first production method of the present invention are surface-treated with a carboxyl group and / or carboxylate group-containing organic compound. Examples of the organic compound having a carboxyl group or a carboxylate group include, for example, acetic acid, succinic acid, formic acid, tartaric acid, malic acid, succinic acid, gluconic acid, maleic acid, phthalic acid, alginic acid, citric acid, and salts thereof. Examples include esters.

  The method for treating the gold colloidal particles (M) is not particularly limited as long as the organic compound is adsorbed or bonded to the surface of the metal colloidal particles (M), and a conventionally known method can be adopted. For example, the treatment can be performed by adding a sufficient amount of the organic compound to the gold colloid particle (M) surface to the dispersion of the gold colloid particle (M).

Alternatively, it can also be prepared by the method of Frens. Specifically, chloroauric acid is added to the organic compound solution having the carboxyl group or carboxylate group, and the mixture is heated and refluxed to give carboxyl group or carboxylate on the surface. Colloidal gold particles adsorbing an organic compound having a group can be prepared.

At this time, the amount of the organic compound used is 5 to 50%, preferably 5 to 30%, of the CMC (critical micelle formation concentration) of the organic compound.
The concentration of the surface-treated gold colloid particle dispersion is not particularly limited, but it is usually preferably in the range of 0.1 to 20% by weight as the solid content.

The gold colloidal particles (M-2) used in the second production method are used without surface treatment.
Silica colloid particles The silica colloid particles (A) used in the present invention are not particularly limited as long as the average particle diameter is within the range described below, and conventionally known silica colloid particles can be used.

The silica colloidal particles preferably have an average particle diameter (D _A ) in the range of 4 to 40 nm, more preferably 5 to 30 nm. When (D _A ) is small, it is difficult to obtain itself, and even if it is obtained, the stability of the silica colloidal particles is insufficient, and it is also difficult to treat the surface, making it difficult to use. When (D _A ) is large, the color tone tends to be impaired due to an increase in optical scattering, and the silica coating layer formed on the surface of the gold colloidal particles becomes thick and becomes unclear when used as a red pigment. Sometimes. Furthermore, there are cases where the gap between the silica colloidal particles to be coated remains and red discoloration cannot be suppressed.

The average particle diameter (D _A ) of the silica colloid particles (A) is preferably smaller than the average particle diameter (D _M ) of the gold colloid particles (M). (D _A ) / (D _M ) is preferably in the range of 0.04 to 1, and more preferably 0.05 to 0.5. When (D _A ) / (D _M ) is small, the colloidal silica particles may agglomerate when they are coated on the gold colloidal particles, and the silica coating layer is thin, and thus heated (overheated). In some cases, the coating layer contracts and cracks occur, and discoloration cannot be suppressed. Even if (D _A ) / (D _M ) is too large, it depends on the average particle diameter (D _M ) of the gold colloid particles (M), but the surface of the gold colloid particles cannot be densely coated with the silica colloid particles. In some cases, the heat resistance becomes insufficient, and the red color tone may be impaired.

The silica colloidal particles (A-1) used in the first production method of the present invention are surface-treated with an amino group-containing silane compound. Examples of the silane compound having an amino group include γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N- ( Phenyl) γ-aminopropyltrimethoxysilane and the like. The silica colloidal particles (A-1) can be treated in the same way as the conventionally known silane coupling agent treatment. Specifically, the required amount of silane compounds having amino groups is dissolved in an aqueous dispersion of silica colloid particles. Add the prepared alcohol solution. Here, the required amount of the silane compound varies depending on the particle diameter (particle surface area) of the silica colloid particles, but is preferably an amount sufficient to sufficiently cover at least the surface of the silica colloid particles.

The silica colloid particles (A-2) used in the second production method of the present invention are surface-treated with a mercaptoto group-containing silane compound. Examples of the silane compound having a mercapto group include γ-mercaptopropyltrimethoxysilane, γ-mercaptoethylmethyldimethoxysilane, γ-mercaptodimethyldimethoxysilane, γ-mercaptopropylethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ -Mercaptopropyltriethoxysilane and the like. Of these, 3 (γ) -mercaptopropyltrimethoxysilane is preferable.

The silica colloidal particles (A-2) can be treated in the same manner as the conventionally known silane coupling agent treatment. Specifically, the silica colloidal particles (A-2) in the aqueous dispersion have a mercapto group. Add an alcohol solution containing the required amount of compound. Here, the required amount of the silane compound varies depending on the particle diameter (particle surface area) of the silica colloidal particles (A-2), but is sufficient to cover at least the surface of the silica colloidal particles (A-2). preferable.
The surface of the silica colloidal particles (A-2) is modified with thiol groups (—SH).

The concentration of the silica colloidal particle (A) dispersion used in the present invention is not particularly limited, but it is usually preferably in the range of 0.1 to 20% by weight as the solid content.
When the surface-treated silica colloidal particle (A) dispersion and the gold colloidal particle (M) dispersion are mixed as described above, the silica colloidal particles (A) are collected on the surface of the gold colloidal particles (M). In the first production method, an amino group and a carboxyl group or a carboxylate group are bonded and self-assembled. In the second production method, colloidal silica particles gather on the surface of the gold colloid particles, and thiol groups (-SH) are bonded to the metal colloid surface and self-assemble.

Although the mixing ratio varies depending on the average particle diameter of each particle, the total amount of the silica colloidal particles (A) on the surface of the gold colloidal particles (M) is an amount that binds in one layer as shown in FIG. A sufficient amount is preferred. For example, when the average particle diameter of the gold colloid particles (M) is 40 nm and the average particle diameter of the silica colloid particles (A) is 5 nm, 4π × (40 nm) ² ÷ 4π × (5 nm) ² = 1600, that is, gold colloid It is preferable to use 1600 or more silica colloidal particles (A) per particle (M).
Silica-coated layer formed Next, if necessary, the dispersion obtained in the mixing step, by adding an acidic silicic acid solution, the surface of the colloidal silica particles layer may be silica-coated.

Here, the acidic silicic acid solution is an acidic silicic acid aqueous solution obtained by subjecting an alkali metal silicate aqueous solution, water glass or the like to dealkalizing ion treatment with an ion exchange resin or the like. The acidic silicic acid solution having a concentration of about 0.1 to 6% by weight as SiO ₂ and a pH of about 0.1 to 3.5 is suitable.

  The amount of the acidic silicic acid solution is not particularly limited as long as it can fill the gap between the silica particles of the coating layer formed by the silica colloid particles (A), but the silica colloid particles (A) forming the silica coating layer are generally not limited. 1 wt% or more, and the thickness of the silica coating layer does not exceed 50 nm (about 50 wt%).

  When the amount of the acidic silicic acid solution is small, particularly when the average particle size of the silica colloid particles is large, the effect of forming the silica coating layer cannot be obtained sufficiently, that is, the heat resistance is insufficient and the production or use is Sometimes a vivid red color cannot be maintained. Moreover, when the thickness of the silica coating layer is too large, the silica coating layer is easily affected by optical scattering, and a clear red color may not be obtained.

In addition, although the addition rate of a silicic acid liquid changes also with the usage-amount of an acidic silicic acid liquid, in order to coat | cover silica finely, adding over as much time as possible is preferable.
Drying and / or heat treatment Further, if necessary, the obtained dispersion can be dried by freeze drying or heat drying. It can be suitably used as a powder pigment by drying.

  The temperature for drying by heating is not particularly limited, but is preferably in the range of 50 to 200 ° C, more preferably 60 to 120 ° C. Heat drying at such a temperature improves the heat resistance and makes it difficult for the resulting silica-coated gold colloid particles to aggregate, resulting in silica-coated gold colloid particles having excellent dispersibility. Further, heat treatment may be performed. The heat treatment temperature is not particularly limited, but is preferably in the range of 200 to 600 ° C, more preferably 250 to 500 ° C. As the heat treatment atmosphere, an oxidizing atmosphere, an inert gas atmosphere, a reducing gas atmosphere, or a combination of these can be used.

  Heat treatment in the above temperature range promotes bonding (bonding) between the colloidal gold particles (M) and the silica colloidal particles (A), and the silica coating layer becomes dense and hardly aggregates. In addition, it is possible to obtain a pigment exhibiting a stable and vivid red color.

  The silica-coated gold colloidal particles thus obtained preferably have a silica coating layer thickness of 4 to 50 nm, more preferably 5 to 30 nm. The average particle diameter of the silica-coated gold colloidal particles is in the range of 13 to 200 nm, preferably 20 to 110 nm.

The silica-coated gold colloidal particles thus obtained can be suitably used as a red pigment because they exhibit a red color (wavelength: 520 to 550 nm).
[Silica-coated gold colloidal particles]
The silica-coated gold colloidal particles according to the present invention are coated on the surface of the colloidal gold particles (A) having an average particle diameter in the range of 4 to 40 nm and the gold colloidal particles (M) having an average particle diameter in the range of 5 to 100 nm. Being done. Such particles can be obtained, for example, by the production method described above.

A schematic view of one embodiment of the silica-coated gold colloidal particles of the present invention is shown in FIG.
Silica colloidal particles (A)
The silica colloidal particles are not particularly limited as long as the average particle diameter is in the range described below, and conventionally known silica colloidal particles can be used as described above.

  The silica colloidal particles (A) constituting the silica-coated gold colloidal particles of the present invention are surface-treated with an amino group-containing silane compound or a mercapto group-containing silane compound. The silane compound having an amino group and the mercapto group-containing silane compound are as described above.

As silica colloid particles (A-1) surface-treated with an amino group-containing silane compound and silica colloid particles (A-2) surface-treated with a mercapto group-containing silane compound, the same particles as described above can be used.

Gold colloidal particles (M)
The gold colloidal particles (M) are not particularly limited as long as the average particle diameter is in the range described later, and conventionally known gold colloidal particles can be used as described above.

When the silica colloid particles are silica colloid particles (A-1) surface-treated with an amino group-containing silane compound, the gold colloid particles (M) are surface-treated with a carboxyl group and / or carboxylate group-containing organic compound. It is desirable that Examples of the organic compound having a carboxyl group or a carboxylate group include those described above.

The silica colloidal particles (A-1) surface-treated with an amino group-containing silane compound coat the surface of the gold colloidal particles (M-1) surface-treated with an organic compound having a carboxyl group and / or a carboxylate group. . In this particle, the silica colloid particle (A-1) and the gold colloid particle (M-1) are composed of an amino group on the surface of the silica colloid particle (A-1) and a carboxyl on the surface of the gold colloid particle (M-1). It is connected by the bond with the group.

The silica colloidal particles (A-2) surface-treated with the mercapto group-containing silane compound coat the surface of the gold colloidal particles (M-2) that are not surface-treated. In this particle, the silica colloid particle (A-2) and the gold colloid particle (M-2) are composed of a thiol group (-SH) and a gold colloid particle (M) on the surface of the silica colloid particle (A-2). Are bonded by hydrogen bonds.

The average particle size (D _A ) of the silica colloid particles (A) is preferably smaller than the average particle size (D _M ) of the gold colloid particles (M), and (D _A ) / (D _M ) is 0.01. Is preferably in the range of ˜1, more preferably 0.02 to 0.5.

If (D _A ) / (D _M ) is too small, the silica colloid particles aggregate together, and a uniform silica colloid coating layer cannot be formed. Also, since the silica colloid coating layer is thin, it shrinks during heating. Cracks may occur, causing discoloration. If (D _A ) / (D _M ) is too large, the surface of the gold colloid particles may not be densely coated with silica colloid particles, heat resistance may be insufficient, and red color tone may be impaired. .

Next, in the silica-coated gold colloidal particles, the silica colloidal particle coating layer is preferably further coated with silica.
The silica coating amount is not particularly limited as long as it can fill the silica colloid particle gap of the silica colloid coating layer formed by the silica colloid particles (A), but the silica colloid particles (A It is desirable that the thickness of the silica colloidal particle coating layer not exceed 50 nm. Such a silica coating layer is derived from an acidic silicic acid solution as described above.

  When the amount of silica in the silica coating layer is small, particularly when the average particle size of the silica colloidal particles is large, the effect of forming the silica coating layer cannot be obtained sufficiently, that is, a vivid red color can be maintained during use. In some cases, when the silica coating layer is too thick, a clear red color may not be obtained.

The thickness of the silica layer comprising the silica colloidal particle (A) coating layer and the silica coating layer formed as necessary is preferably 4 to 50 nm, more preferably 5 to 30 nm.
When the silica layer is too thin, when the silica-coated gold colloidal particles are used as a red pigment at a high temperature, a clear red color may not be maintained. If the thickness of the silica layer is too thick, a clear red color may not be obtained.

  The average particle diameter of the silica-coated gold colloidal particles according to the present invention is appropriately selected depending on the application, but is usually in the range of 13 to 200 nm, preferably 20 to 110 nm. When the silica-coated gold colloidal particles have a small average particle size, they may be excellent in heat resistance and may not be able to obtain vivid red particles. When the average particle diameter of the silica-coated gold colloidal particles is too large, particles exhibiting a bright red color may not be obtained.

Since the silica-coated gold colloidal particles of the present invention exhibit a red color (wavelength: 520 to 550 nm), they can be suitably used as a red pigment.
Such a silica-coated gold colloid according to the present invention is discolored even when used in a high-temperature environment where it has been difficult to use colloidal gold particles, such as a color tube for a cathode ray tube (color filter) or ceramics. It becomes possible to use without doing.
[Example]
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
[Example 1]
Preparation of surface-treated gold colloidal particle (Au-1) dispersion Gold colloidal particle dispersion (manufactured by BB International: average particle diameter 50 nm, Au concentration 5% by weight)
200 g is dispersed in 300 mL of pure water, 4 g of sodium citrate is added thereto and stirred for 1 hour, free sodium citrate is removed with both ion exchange resins, and surface-treated metal colloidal particles (Au-1) A dispersion was prepared.

Preparation of surface-treated silica colloidal particle (S-1) dispersion Silica colloidal particle dispersion (catalyst chemical industry Co., Ltd .: Cataloid SI-30, average particle size 12 nm, SiO ₂ concentration 30% by weight) 49 g of water / ethanol (50/50) The mixture was dispersed in 68 g of a mixed solvent. 0.25 g of γ-aminopropyltriethoxysilane was added to this dispersion, and the mixture was stirred for 1 hour, and then a silica colloid particle (surface-treated with an amino group-containing silane compound by stirring at 80 ° C. for 2 hours in an autoclave) S-1) A dispersion was prepared.

Preparation of silica-coated gold colloidal particles (1) The silica colloidal particle (S-1) dispersion prepared above and the surface-treated gold colloidal particle (Au-1) dispersion are mixed and stirred for 1 hour to produce silica-coated gold. A dispersion of colloidal particles (1) was prepared.

The silica-coated gold colloidal particle (1) dispersion is evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (1) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of the silica-coated gold colloidal particles (1), the observation of the aggregated particles after drying, the observation of the aggregated particles after heat treatment (heat resistance), and the red sharpness after the heat treatment were evaluated. The results are shown in Table 1.

Observation of Aggregated Particles An electron micrograph of the powder after evaporating and drying at 120 ° C. was observed and evaluated according to the following criteria.
Almost no agglomerated particles are observed. : ○
Slightly aggregated particles are observed. : △
Many agglomerated particles are observed. : ×
An electron micrograph of the heat-resistant silica-coated gold colloidal particles (1) was observed and evaluated according to the following criteria.

Almost no agglomerated particles are observed. : ○
Slightly aggregated particles are observed. : △
Many agglomerated particles are observed. : ×
The redness of the red- coated silica-coated gold colloidal particles (1) was visually observed and evaluated according to the following criteria.

It has a bright red color. : ○
It has a relatively bright red color. : △
Discolored to the extent that red is not recognized. : ×
[Example 2]
Preparation of silica-coated gold colloidal particles (2) A silica-coated gold colloidal particle (1) dispersion was prepared in the same manner as in Example 1. While stirring this, 13.1 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added in 1 hour,
Next, the mixture was aged at 80 ° C. for 1 hour to prepare a dispersion of silica-coated gold colloidal particles (2).

The silica-coated gold colloidal particle (2) dispersion is evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (2) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of the silica-coated gold colloidal particles (2), observation of the aggregated particles after drying, observation of the aggregated particles after heat treatment (heat resistance), and redness after the heat treatment were evaluated, and the results are shown in Table 1. Indicated.
[Example 3]
Preparation of surface-treated silica colloidal particle (S-3) dispersion 3 g of silica colloidal particle dispersion (catalyst chemical industry Co., Ltd .: Cataloid SI-550, average particle diameter 5 nm, SiO ₂ concentration 20% by weight) was added to water / ethanol. (50/50) The mixture was dispersed in 27 g of a mixed solvent.

0.25 g of γ-aminopropyltriethoxysilane was added to this dispersion, and the mixture was stirred for 1 hour, and then a silica colloid particle (surface-treated with an amino group-containing silane compound by stirring at 80 ° C. for 2 hours in an autoclave) S-3) A dispersion was prepared.
Preparation of silica-coated gold colloidal particles (3) A silica colloidal particle (S-3) dispersion and a surface-treated gold colloidal particle (Au-1) dispersion prepared in the same manner as in Example 1 were mixed for 1 hour. A silica-coated gold colloidal particle dispersion was prepared by stirring.

Next, while stirring this, 4.5 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added over 30 minutes, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (3) A dispersion was prepared.

The silica-coated gold colloidal particle (3) dispersion is evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (3) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of the silica-coated gold colloidal particles (3), observation of the aggregated particles after drying, observation of the aggregated particles after heat treatment (heat resistance), and the redness after heat treatment were evaluated, and the results are shown in Table 1. Indicated.
[Example 4]
Preparation of surface-treated silica colloidal particle (S-4) dispersion Silica colloidal particle dispersion (catalyst chemical industry, Cataloid SI-50, average particle diameter 25 nm, SiO ₂ concentration 48 wt%) 6.3 g of water / Ethanol (50/50) was dispersed in 146 g of a mixed solvent. 0.25 g of γ-aminopropyltriethoxysilane was added to this dispersion, and the mixture was stirred for 1 hour, and then a silica colloid particle (surface-treated with an amino group-containing silane compound by stirring at 80 ° C. for 2 hours in an autoclave) S-4) A dispersion was prepared.

Preparation of silica-coated gold colloidal particles (4) A silica colloidal particle (S-4) dispersion and a surface-treated gold colloidal particle (Au-1) dispersion prepared in the same manner as in Example 1 were mixed for 1 hour. A silica-coated gold colloidal particle dispersion was prepared by stirring.

Next, 27.3 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added over 2 hours with stirring, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (4) A dispersion was prepared.

The silica-coated gold colloidal particle (4) dispersion is evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (4) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of silica-coated gold colloidal particles (4), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), and redness after heat treatment were evaluated, and the results are shown in Table 1. Indicated.
[Example 5]
Preparation of surface-treated gold colloidal particle (Au-5) dispersion Gold colloidal particle dispersion (manufactured by BB International: average particle diameter 20 nm, Au concentration 5% by weight
) 200 g was dispersed in 300 mL of pure water, 18 g of sodium citrate was added thereto, and the mixture was stirred for 1 hour. Then, free sodium citrate was removed with both ion exchange resins, and the surface-treated gold colloidal particles (Au-5 ) A dispersion was prepared.

Preparation of silica-coated gold colloidal particles (5) A surface-treated silica colloidal particle (S-3) dispersion prepared in the same manner as in Example 3 and a surface-treated gold colloidal particle (Au-5) dispersion were mixed. The mixture was stirred for 1 hour to prepare a silica-coated gold colloid particle dispersion.

Next, 13.7 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added over 1 hour while stirring this, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (5) A dispersion was prepared.

The silica-coated gold colloidal particle (5) dispersion was evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (5) powder was obtained by heat treatment at 00 ° C. for 2 hours.
Evaluation of average particle size of silica-coated gold colloidal particles (5), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), red sharpness after heat treatment, and the results are shown in the table It was.
[Example 6]
Preparation of surface-treated gold colloidal particle (Au-6) dispersion Gold colloidal particle dispersion (manufactured by BB International: average particle diameter 80 nm, Au concentration 5% by weight)
200 g was dispersed in 300 mL of pure water, 4.4 g of citric acid was added thereto and stirred for 1 hour, free sodium citrate was removed with both ion exchange resins, and surface treated gold colloidal particles (Au-6 ) A dispersion was prepared.

Preparation of silica-coated gold colloidal particles (6) A surface-treated silica colloidal particle (S-4) dispersion prepared in the same manner as in Example 4 and a surface-treated gold colloidal particle (Au-6) dispersion were mixed. The mixture was stirred for 1 hour to prepare a silica-coated gold colloid particle dispersion.

Next, while stirring this, 17.1 g of acidic silicate solution (SiO ₂ concentration 3.0 wt%, pH 2) was added in 1.5 hours, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles ( 6) A dispersion was prepared.

The silica-coated gold colloidal particle (6) dispersion was evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (6) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of the silica-coated gold colloidal particles (6), observation of the aggregated particles after drying, observation of the aggregated particles after heat treatment (heat resistance), and redness after the heat treatment were evaluated, and the results are shown in Table 1. Indicated.
[Example 7]
Preparation of surface treated silica colloidal particle (S-7) dispersion Silica colloidal particle dispersion (catalyst chemical industry, Cataloid SI-30, average particle size 12 nm, SiO ₂ concentration 30 wt%) 4.9 g in water / Ethanol (50/50) was dispersed in 68 g of a mixed solvent. To this dispersion was added 0.25 g of γ-mercaptopropyltrimethoxysilane, and the mixture was stirred for 1 hour, then stirred at 80 ° C. for 2 hours in an autoclave, surface-treated with a mercaptoto group-containing silane compound, and thiol on the surface. A dispersion of colloidal silica particles (S-7) having groups was prepared.

Preparation of gold colloidal particle (Au-7) dispersion Gold colloidal particle dispersion (Au-7) was dispersed by dispersing 200 g of gold colloidal particle dispersion (BBInternational: average particle diameter 50 nm, Au concentration 5% by weight) in 300 mL of pure water. A liquid was prepared.

Preparation of silica-coated gold colloidal particles (7) The silica colloidal particle (S-7) dispersion prepared above and the gold colloidal particle (Au-7) dispersion are mixed and stirred for 1 hour to produce silica-coated gold colloidal particles. (7) A dispersion was prepared.

The silica-coated gold colloidal particle (7) dispersion was evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (7) powder was obtained by heat treatment at 00 ° C. for 2 hours.
Evaluation of average particle size of silica-coated gold colloidal particles (7), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), redness after heat treatment, and results are shown in the table It was.
[Example 8]
Preparation of silica-coated gold colloidal particles (8) In the same manner as in Example 7, a silica-coated gold colloidal particle dispersion was prepared.

Next, an acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) while stirring the solution 13.
1g was added in 1 hour, and then aged at 80 ° C for 1 hour to produce silica-coated gold colloidal particles (8)
A dispersion was prepared.

The silica-coated gold colloidal particle (8) dispersion was evaporated to dryness at 120 ° C.
A silica-coated gold colloidal particle (8) powder was obtained by heat treatment at 00 ° C. for 2 hours.
The average particle diameter of the silica-coated gold colloidal particles (8), observation of the aggregated particles after drying, observation of the aggregated particles after heat treatment (heat resistance), and redness after the heat treatment were evaluated, and the results are shown in Table 1. Indicated.
[Comparative Example 1]
Preparation of silica-coated gold colloidal particles (R1) In the same manner as in Example 7, a gold colloidal particle dispersion having a concentration of 1% by weight having no carboxyl group on the surface was prepared.

Next, 61.7 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added over 5 hours while stirring the mixture, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (R1). A dispersion was prepared.

The silica-coated gold colloidal particle (R1) dispersion was evaporated to dryness at 120 ° C. and heat-treated at 400 ° C. for 2 hours in a hydrogen gas atmosphere to obtain silica-coated gold colloidal particle (R1) powder.
Evaluation of average particle diameter of silica-coated gold colloidal particles (R1), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), redness after heat treatment, and results are shown in Table 1. Indicated. [Comparative Example 2]
Preparation of silica-coated gold colloidal particles (R2) A surface-treated gold colloidal particle (Au-1) dispersion was prepared in the same manner as in Example 1.

Next, 61.7 g of acidic silicic acid solution (SiO ₂ concentration 3.0 wt%, pH 2) was added over 5 hours while stirring the mixture, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (R2). A dispersion was prepared.

The silica-coated gold colloidal particle (R2) dispersion was evaporated to dryness at 120 ° C. and heat-treated at 400 ° C. for 2 hours in a hydrogen gas atmosphere to obtain silica-coated gold colloidal particle (R2) powder.
Evaluation of average particle diameter of silica-coated gold colloidal particles (R2), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), redness after heat treatment, and results are shown in Table 1. Indicated. [Comparative Example 3]
Preparation of surface-treated gold colloidal particle (RAu-3) dispersion 200 g of gold colloidal particle dispersion (manufactured by BB International: average particle diameter 150 nm, Au concentration 5% by weight) is dispersed in 300 mL of pure water. After adding 4 g and stirring for 1 hour, free sodium citrate was removed with both ion exchange resins to prepare a surface-treated gold colloidal particle (RAu-3) dispersion.

Preparation of silica-coated gold colloidal particles (R3) A silica colloidal particle (S-1) dispersion prepared in the same manner as in Example 1 and a surface-treated gold colloidal particle (RAu-3) dispersion were mixed for 1 hour. Silica-coated gold colloidal particle dispersion (R3) with stirring
Was prepared.

The silica-coated gold colloidal particle (R3) dispersion was evaporated to dryness at 120 ° C. and heat-treated at 400 ° C. for 2 hours in a hydrogen gas atmosphere to obtain silica-coated gold colloidal particle (R3) powder. Evaluation of average particle diameter of silica-coated gold colloidal particles (R3), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), redness after heat treatment, and results are shown in Table 1. Indicated.
[Comparative Example 4]
Preparation of silica-coated gold colloidal particles (R4) Silica colloidal particle (S-1) dispersion prepared in the same manner as in Example 1, and surface-treated gold colloidal particles (RAu-3) prepared in the same manner as in Comparative Example 3 The dispersion was mixed and stirred for 1 hour to prepare a silica-coated gold colloidal particle dispersion.

Next, 4.4 g of acidic silicic acid solution (SiO ₂ concentration: 3.0 wt%, pH 2) was added over 30 minutes while stirring the mixture, and then aged at 80 ° C. for 1 hour to produce silica-coated gold colloidal particles (R4). A dispersion was prepared.

The silica-coated gold colloidal particle (R4) dispersion was evaporated to dryness at 120 ° C. and heat-treated at 400 ° C. for 2 hours in a hydrogen gas atmosphere to obtain silica-coated gold colloidal particle (R4) powder.
Evaluation of average particle diameter of silica-coated gold colloidal particles (R4), observation of aggregated particles after drying, observation of aggregated particles after heat treatment (heat resistance), redness after heat treatment, and results are shown in Table 1. Indicated.

1 shows the schematic diagram of one embodiment of silica-coated gold colloidal particles according to the present invention.

Claims (8)

A gold colloidal particle dispersion having an average particle diameter in the range of 5 to 100 nm and surface-treated with a carboxyl group and / or carboxylate group-containing organic compound;
A method for producing silica-coated gold colloidal particles, comprising mixing a silica colloidal particle dispersion having an average particle diameter in the range of 4 to 40 nm and surface-treated with an amino group-containing silane compound. A colloidal gold particle dispersion having an average particle size in the range of 5 to 100 nm;
Silica-coated gold having an average particle diameter in the range of 4 to 40 nm and a silica colloidal particle dispersion liquid surface-treated with a mercapto group-containing silane compound and introduced with thiol groups (—SH groups) A method for producing colloidal particles.   The method for producing silica-coated gold colloidal particles according to claim 1 or 2, wherein after the dispersion is mixed, an acidic silicic acid solution is further added to coat the surface of the silica colloidal particles.   Furthermore, it dries and / or heat-processes, The manufacturing method of the silica covering gold colloid particle in any one of Claims 1-3 characterized by the above-mentioned.   A silica-coated gold colloidal particle having a silica colloidal particle having an average particle diameter in the range of 4 to 40 nm and a surface of the gold colloidal particle having an average particle diameter in the range of 5 to 100 nm.   The silica-coated gold colloidal particles according to claim 5, further comprising a silica coating layer.   The silica-coated gold colloidal particles according to claim 5 or 6, wherein the thickness of the silica layer (the total of the silica colloidal particle layer and the silica coating layer formed as necessary) is in the range of 4 to 50 nm.   The silica-coated gold colloidal particles according to any one of claims 5 to 7, wherein the silica-coated gold colloidal particles exhibit a red color (wavelength: 520 to 550 nm).

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