JP2019159186A - Metal-resin composite dispersion liquid, heat shield paint, method of manufacturing metal-containing resin film or infrared reflective film using the same, and method of manufacturing metal-resin composite dispersion liquid - Google Patents

Abstract

To provide a novel material that can be used to form an infrared reflective film using a simple method, a method of manufacturing the infrared reflective film using such material, and the like.SOLUTION: A metal-resin composite dispersion liquid is provided, comprising fine spheres, each comprising an aggregate of fine resin particles and containing a water phase therein, where the spheres are dispersed in an organic phase to form a w/o pickering emulsion, and where the water phase contains fine metal particles. The metal-resin composite dispersion liquid can be used as a heat shield paint.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a metal / resin composite dispersion, a thermal barrier coating, a method for producing a metal-containing resin film or an infrared reflective film using them, and a method for producing a metal / resin composite dispersion.

  In recent years, countermeasures for climate change, heat island phenomenon, reduction of cooling load, etc. are required, but as an effective countermeasure for any of them, development of a material that reflects solar infrared rays (heat) has attracted attention. . Infrared rays occupy about 50% of the total sunlight, and have the property of being converted into thermal energy when absorbed by substances. Infrared rays include near-infrared rays, infrared rays, and far-infrared rays in order of short wavelength (in order from the closest to visible light).

  One of the materials that reflect infrared rays is a highly reflective paint. This has a function of reflecting near-infrared light contained in sunlight by the coating film by applying the coating to the object to form a coating film and suppressing the temperature rise of the object. The coating material having such a function is applied to roads, sidewalks, and the like, and is used for the purpose of alleviating the heat island phenomenon (see Patent Document 1 as an example of such a coating material).

  As another infrared reflective material, a heat shield film is exemplified. As one form of such a film, a film that reflects infrared rays while allowing visible light to pass therethrough by combining a plurality of films having a plurality of different reflectances (see, for example, Patent Document 2). . In addition, as another form of such a film, by dispersing nano-sized metal tabular grains in the film under specific conditions, visible light can be passed while infrared rays are reflected (for example, for example) (See Patent Document 3). These films allow visible light to pass through while blocking infrared rays while being attached to a window glass or the like, for example, thereby making it possible to suppress an increase in room temperature while taking in outside light into the room. .

JP 2004-251108 A Japanese National Patent Publication No. 11-508380 JP 2012-215811 A

  These thermal barrier films can be easily shielded from infrared rays by being attached to a window or the like. On the other hand, in order to manufacture such a film, enormous effort is required to combine multiple layers of film and precise orientation adjustment of internal particles is required, so that a corresponding cost is required. In addition, there are few examples of infrared reflecting films that reflect infrared rays while exhibiting transparency in the visible light region.

  The present invention has been made in view of the above circumstances, and provides a novel material capable of forming an infrared reflective film by a simpler method, a method for producing an infrared reflective film using the same, and the like. With the goal.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention include an aqueous phase in which metal fine particles are dispersed inside a fine sphere formed by collecting resin fine particles, and the sphere is in the organic phase. It has been found that a resin film containing metal fine particles is formed by preparing a dispersion liquid that is dispersed in an aqueous solution to form a w / o-type pickering emulsion, and further applying the dispersion liquid to a target surface and drying. If the metal fine particles are nano-sized noble metal particles, the present inventors have a characteristic that the resin film transmits visible light while reflecting infrared light by surface plasmon resonance of the noble metal particles. I found out. The present invention has been completed based on these findings, and provides the following.

  (1) The present invention is a dispersion in which a fine sphere formed by collecting resin fine particles contains an aqueous phase, and the sphere is dispersed in an organic phase to form a w / o-type pickering emulsion. A metal and resin composite dispersion characterized by containing metal fine particles in the aqueous phase.

  The metal forming the metal nanoparticles is preferably at least one selected from the group consisting of gold, silver, platinum, palladium, rhodium, and copper.

  The resin fine particles are preferably at least one selected from the group consisting of a polymer of an acrylic ester and a polymer of a methacrylate.

  (2) The present invention is also a thermal barrier paint containing the above metal and resin composite dispersion.

  (3) This invention is also a manufacturing method of the metal containing resin film characterized by including the process of apply | coating the said metal and resin composite dispersion liquid.

  (4) The present invention is also a method for producing an infrared reflecting film, comprising a step of forming a metal-containing resin film by the method described in the above item (3).

  (5) The present invention provides an addition step in which a metal ion-containing aqueous solution and resin fine particles are added into an oil phase to obtain a mixture, and the mixture obtained in the addition step is emulsified under high shear to provide a w / o And an emulsification step for forming a pickering emulsion, and further a method for producing a metal and resin composite dispersion comprising a reduction step of reducing the metal ions into metal particles.

  The reduction step is preferably performed before or simultaneously with the emulsification step.

  The reduction in the reduction step is preferably performed using ascorbic acid or aldose as a reducing agent.

  The aldose is preferably glucose.

  (6) The present invention is also a method for producing an infrared reflecting film, comprising a step of applying the metal and resin composite dispersion obtained by the above production method and drying the coating film obtained thereby.

  ADVANTAGE OF THE INVENTION According to this invention, the novel material which can form an infrared reflective film by a simpler method, the manufacturing method of an infrared reflective film using the same, etc. are provided.

FIG. 1 is a schematic diagram illustrating a w / o-type pickering emulsion contained in a metal and resin composite dispersion of the present invention. FIG. 2A is a chart showing the particle size distribution of the prepared resin fine particles by a dynamic light scattering method, and FIG. 2B is an SEM image of the prepared resin fine particles. FIG. 3 is an image observed with an optical microscope for the metal and resin composite dispersion (A). FIG. 4 is an observation image of the metal and resin composite dispersion (C) with an optical microscope. FIG. 5 is a chart showing the diffuse reflectance of the metal-containing resin film prepared from each of the metal and resin composite dispersions (A) to (C).

  Hereinafter, for one embodiment or one embodiment of the present invention, a metal and resin composite dispersion, a method for producing a metal and resin composite dispersion, a thermal barrier coating, a method for producing a metal-containing resin film, and a method for producing an infrared reflective film These will be described in order.

<Metal and resin composite dispersion>
First, an embodiment of the metal and resin composite dispersion of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a w / o-type pickering emulsion contained in a metal and resin composite dispersion of the present invention.

  The metal-resin composite dispersion of the present invention contains a water phase inside a small sphere formed by collecting resin fine particles, and the sphere is dispersed in an organic phase to form a w / o-type pickering emulsion. A liquid characterized in that the aqueous phase contains fine metal particles. A pickering emulsion is an emulsion stabilized by solid fine particles adsorbed on a liquid-liquid interface. A normal w / o type emulsion (water-in-oil emulsion) is formed by dispersing fine water droplets in the oil phase, whereas a w / o-type pickering emulsion is formed by spherically covering water droplets covered with solid fine particles in the oil phase. Formed dispersed in. The solid fine particles have a function of coating a water droplet like a shell to form a sphere containing an aqueous phase therein and stabilizing the sphere in the oil phase.

  The w / o pickering emulsion in the present invention will be described with reference to FIG. As shown in FIG. 1, the solid fine particles that play the role of the “shell” in the present invention are resin fine particles. The resin fine particles are added to a liquid in a state where the oil phase and the aqueous phase are separated, and then the liquid is subjected to high shear by means such as being subjected to treatment with a homogenizer or the like, thereby forming fine particles and forming water droplets. The w / o-type pickering emulsion in which the water phase is covered and water droplets are stabilized in the oil phase is formed.

  At this time, if metal ions are present in the water phase, these metal ions are taken into the water phase covered with the shells of the resin fine particles. Then, by reducing the taken-in metal ions into a single metal with a reducing agent, the metal fine particles are contained in the aqueous phase covered with the shell of the resin fine particles. In FIG. 1, the metal ions taken into the shell of the resin fine particles are shown as silver ions, but any metal ions can be selected. Further, FIG. 1 shows that the reduction operation is performed after the metal ions are taken into the shell of the resin fine particles. However, the reduction operation may be performed before the metal ions are taken into the shell of the resin fine particles. Good. In any case, there is no difference in that metal fine particles are contained in the aqueous phase in the shell made of resin fine particles. The aqueous phase covered with the resin fine particle shell becomes a w / o-type pickering emulsion and is dispersed in the oil phase to form the metal and resin composite dispersion of the present invention.

  One of the points of the w / o-type pickering emulsion in the present invention is to hold metal fine particles in a shell made of resin fine particles as described above. That is, when a dispersion liquid containing this is applied to the surface of the substrate, the oil phase contained in the dispersion liquid evaporates on the substrate, and the resin fine particles constituting the shell are bonded to each other to form a resin film. Since the inside of the shell contains metal fine particles, the formed resin film contains metal fine particles inside. If the metal fine particles are nano-sized noble metals, the obtained resin film reflects infrared light while transmitting visible light due to surface plasmon resonance by the metal fine particles. Even if the metal fine particles do not satisfy such conditions, light (visible light and infrared rays) is reflected by the presence of the metal fine particles in the resin film, and a heat shielding effect is obtained. That is, by using the metal and resin composite dispersion of the present invention, a resin film having a heat shielding effect can be easily obtained.

  The fine resin particles forming the shell are not particularly limited, but are preferably selected from a polymer of acrylic ester and a polymer of methacrylate. This is because these polymers have a polarity suitable for being present at the liquid-liquid interface between the oil phase and the water phase. Examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, and the like. Examples of the methacrylate ester include methyl methacrylate and methacrylic acid. Examples include ethyl, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, pentyl methacrylate and the like. Among these, methyl methacrylate is preferable. In the following description, acrylic acid and methacrylic acid are also referred to as (meth) acrylic acid. That is, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester. The particle diameter of the resin fine particles is preferably about 0.5 to 9 μm.

  The metal fine particles are not particularly limited, but are preferably at least one selected from the group consisting of gold, silver, platinum, palladium, rhodium, and copper. These metal fine particles may be used alone or in combination of two or more. If the use of the metal and resin composite dispersion of the present invention is to prepare a heat-shielding resin film, it is preferable to use silver as the metal fine particles. When other metals are used, the metal and resin composite dispersion of the present invention can be used for preparing a resin film having a catalytic action according to the metal. The size of the metal fine particles can be about 1 nm to 50 μm, but may be appropriately adjusted according to the application.

  Examples of the size of a sphere composed of an aqueous phase covered with resin fine particles as a shell (that is, a dispersoid of a w / o pickering emulsion) include about 1 μm to 100 μm. Further, the content of the metal fine particles in the aqueous phase contained in the particles can be about 2% by mass to 15% by mass, but is not particularly limited.

  The oil phase is not particularly limited as long as it separates when mixed with the aqueous phase, but if the metal and resin composite dispersion of the present invention is used for coating film formation, it is a volatile organic solvent. Is preferred. Examples of such an organic solvent include hydrocarbon organic solvents having 5 or more carbon atoms. Examples of such hydrocarbon organic solvents include pentane, hexane, heptane, octane, cyclohexane, benzene, toluene, xylene and the like. Among these, heptane is preferable.

  The water phase is not particularly limited as long as it is phase-separated when mixed with the oil phase, and water can be mentioned. The water in this case may contain various salts, water-soluble organic solvents, water-soluble resins and the like. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol and propanol, acetone and the like. From the viewpoint of allowing the metal fine particles to stably exist without agglomerating in the aqueous phase contained in the shell, the aqueous phase preferably contains a water-soluble polymer. In this case, the water-soluble polymer includes polyvinyl pyrrolidone.

<Method for producing metal and resin composite dispersion>
Next, an embodiment of the method for producing the metal and resin composite dispersion will be described. The method for producing a metal and resin composite dispersion according to the present invention includes an addition step of obtaining a mixture by adding a metal ion-containing aqueous solution and resin fine particles into an oil phase, and an emulsified state of the mixture obtained in the addition step under high shear And an emulsification step of forming a w / o pickering emulsion, and further, a reduction step of reducing the metal ions into metal particles. Hereinafter, each step will be described.

[Addition process]
The adding step is a step of adding a metal ion-containing aqueous solution and resin fine particles into the oil phase to obtain a mixture.

  The metal ion-containing aqueous solution is obtained by dissolving a desired metal salt in water. Water is the same as that described as the water phase in the description of the metal and resin composite fine particle dispersion. The desired metal may be determined in accordance with the type of metal fine particles desired to be contained in the aqueous phase existing inside the shell made of resin fine particles in the metal and resin composite fine particle dispersion. The metal is the same as that described for the metal and resin composite fine particles. For example, if silver fine particles are to be included as the metal fine particles, silver ions are selected as the metal ions. The counter ion of the metal ion is not particularly limited as long as it does not affect the water solubility of the metal ion. Such counter ions include nitrate ions, chloride ions, hydroxides, fluoride ions, and the like. For example, if a silver ion is selected as the metal ion, silver nitrate is preferably used. Examples of the metal ion concentration in the aqueous solution include about 0.1 mol / L to 10 mol / L. This aqueous solution containing metal ions becomes an aqueous phase.

  The resin constituting the resin fine particles is the same as that described for the metal and resin composite dispersion. These resin fine particles are used in this embodiment. As already described, the particle diameter of the resin fine particles is preferably about 0.5 μm to 9 μm. As such resin fine particles, commercially available ones may be used, or those obtained by suspension polymerization of (meth) acrylic acid esters may be used. The (meth) acrylic acid ester monomer used in such suspension polymerization is as described above.

  When preparing resin fine particles by suspension polymerization of (meth) acrylic acid ester, a mixed solution of (meth) acrylic acid ester and radical polymerization initiator is dropped into an organic solvent at room temperature with stirring, and then stirred. What is necessary is just to heat and radical polymerization. At this time, resin fine particles having a uniform particle diameter can be obtained by dissolving a polyolefin having a relatively high molecular weight in the organic solvent. As such polyolefin, polyisobutylene having a weight average molecular weight of about 100,000 to 1,000,000 is preferably mentioned. About 0.1-0.5 can be mentioned about the usage-amount of polyolefin with respect to (meth) acrylic acid ester by molar ratio (polyolefin / (meth) acrylic acid ester). Examples of the organic solvent include hydrocarbon organic solvents having 5 or more carbon atoms. Examples of such a hydrocarbon-based organic solvent include pentane, hexane, heptane, octane, cyclohexane, benzene, toluene, xylene, and the like. Among these, heptane is preferable. Known radical polymerization initiators can be used without particular limitation. Examples of such radical polymerization initiators include azoisobutyronitrile and benzoyl peroxide. In addition, the technique of suspension polymerization of (meth) acrylic acid ester is well-known, and what is necessary is just to prepare resin fine particles according to the technique. The hydrocarbon-based organic solvent becomes an oil phase.

  By using the suspension polymerization method as described above, a dispersion of polymer fine particles of (meth) acrylic acid ester dispersed in an organic solvent can be obtained, and the dispersion can be used as it is as an oil phase.

  It is preferable to add a water-soluble polymer to the aqueous phase in addition to the metal ions. The water-soluble polymer stabilizes the metal particles obtained in the reduction step described later and contributes to suppressing the aggregation. As such a water-soluble polymer, polyvinylpyrrolidone is preferably exemplified.

  The aqueous phase, resin fine particles, and oil phase are mixed to form a mixture. The obtained mixture is subjected to an emulsification step.

[Emulsification process]
An emulsification process is a process of forming a w / o pickering emulsion by making the mixture obtained at the said addition process into an emulsified state under high shear.

  Examples of means for applying a high shear force when emulsifying the mixture include stirring the mixture with a device such as a homogenizer or a high shear mixer. When the mixture is treated under such high shear, the resin fine particles gather at the boundary between the aqueous phase and the oil phase in the mixture, and the aqueous phase is covered with the resin fine particles to form a sphere. The resin fine particles become a shell covering the surface of the aqueous phase and stabilize the w / o pickering emulsion.

  Examples of the size of the sphere composed of the aqueous phase and the shell include 1 μm to 100 μm. Sampling is appropriately performed while the mixture is treated under high shear, and the treatment under high shear may be continued until formation of a sphere having a uniform particle diameter is confirmed by microscopic observation.

[Reduction process]
The reduction step is a step of reducing metal ions contained in the aqueous phase to form metal fine particles. This step may be performed before the emulsification step, may be performed simultaneously with the emulsification step, or may be performed after the end of the emulsification step. However, since the w / o-type pickering emulsion formed in the emulsification process may be destroyed if the reduction process is performed after the end of the emulsification process, this process is performed before the emulsification process or the emulsification process. It is preferable to carry out at the same time.

  Through the reduction process, metal ions contained in the aqueous phase are reduced, and metal fine particles are formed. The formed metal fine particles are taken into the water droplets (dispersoid) of the w / o pickering emulsion covered with the shell of resin fine particles.

  The reducing agent used for the reduction of the metal ions is not particularly limited. However, if a reducing agent having a too strong action is used, the reduction of the metal ions proceeds at a stretch to form metal fine particles having a large variation in the particle size range, or w / o Since the pickering emulsion may be destroyed, it is preferable to use a reducing agent such as ascorbic acid or aldose. As an addition amount of a reducing agent, about 1 to 2 times the equivalent number of metal ions can be given. The reducing agent is dissolved in a small amount of water (about 5 to 10 mL) and added to the mixture.

  When aldose is used as the reducing agent, the size of the metal fine particles generated in the aqueous phase becomes nano-sized, and the action of the metal fine particles allows the resin film prepared from the metal and resin composite dispersion to pass visible light. It is preferable because it reflects infrared rays. Among the aldoses, glucose is particularly preferable as the reducing agent. When ascorbic acid is used as the reducing agent, the size of the metal fine particles tends to be larger than when aldose is used, and not only infrared light but also visible light having a wavelength of 400 nm to 800 nm is reflected by about 50% to 75%. become. However, even when any of these reducing agents is used, the obtained resin film has both the transparency in the visible light region and the heat shielding property, and still has superior properties as a material.

<Thermal insulation paint>
Next, an embodiment of the thermal barrier paint of the present invention will be described. The thermal barrier paint of the present invention is characterized by containing the metal and resin composite dispersion of the present invention. As described above, the w / o-type pickering emulsion contained in the metal and resin composite dispersion of the present invention is one of the points that the metal fine particles are contained in the shell made of resin fine particles as described above. I will. Therefore, when a dispersion liquid containing this is applied to the surface of a certain base material, the oil phase contained in the dispersion liquid evaporates on the base material, and the resin fine particles constituting the shell are bonded together to form a resin film. . Since the inside of the shell contains metal fine particles, the formed resin film contains metal fine particles inside.

  Since the metal fine particles reflect infrared light by surface plasmon resonance and transmit visible light, the formed resin film also has the same characteristics. Further, even if the metal fine particles do not satisfy such conditions, a heat shielding effect due to the presence of the metal fine particles in the resin film can be obtained. That is, the metal and resin composite dispersion of the present invention has both the film-forming property when applied and the infrared reflection property of the obtained resin film, and can itself be used as a heat-shielding paint.

  The thermal barrier coating of the present invention has been completed by paying attention to such points, and a resin film having a thermal barrier (infrared reflection) effect is applied to the surface of the base material by being applied to the base material. Let it form. The thermal barrier paint of the present invention may contain various components such as a colorant and a stabilizer in addition to the metal and resin composite dispersion of the present invention.

  Examples of the base material include all materials that are desired to provide a heat shielding effect, such as window glass and road surfaces. The thermal barrier paint of the present invention imparts thermal barrier properties to the substrate by a simple means of application.

<Method for producing metal-containing resin film>
Next, an embodiment of the method for producing a metal-containing resin film of the present invention will be described. The method for producing a metal-containing resin film of the present invention includes a step of applying the metal and resin composite dispersion of the present invention. As already explained, the metal / resin composite dispersion of the present invention is applied to form a resin film containing fine metal particles. This embodiment focuses on such characteristics.

  As described above, the obtained metal-containing resin film exhibits an infrared reflecting action and a catalytic action based on the presence of metal fine particles.

<Infrared reflective film manufacturing method>
Next, an embodiment of the method for producing an infrared reflective film of the present invention will be described. The manufacturing method of the infrared reflective film of this invention includes the process of forming a metal containing resin film with the manufacturing method of the said metal containing resin film. That is, the method for producing an infrared reflective film of the present invention includes a step of applying the metal and resin composite dispersion and drying a coating film obtained thereby. Since these have already been described, the description thereof is omitted here.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example at all.

[Preparation of resin fine particles]
A 200 mL four-necked round bottom flask was equipped with a stirrer, an Allen condenser tube, a septum rubber, a nitrogen inlet tube and a thermometer, 110.5 mL of heptane and 2.56 g of polyisobutylene (weight average molecular weight 500000) were added, and a constant temperature of 70 ° C. While heating in the aqueous layer, the mixture was stirred at a rotational speed of 100 rpm until the polyisobutylene was dissolved in a nitrogen atmosphere. Thereafter, a solution prepared by dissolving 0.105 g (6.39 × 10 ⁻⁴ mol) of azoisobutyronitrile in 6.40 g (6.39 × 10 ⁻² mol) of methyl methacrylate was added at 0.109 mL / min with a syringe pump. After adding at a rate, the reaction was allowed to stir for 7 hours. Thereafter, the temperature of the constant temperature water layer was raised to 80 ° C. to polymerize the remaining monomer, and the contents were cooled to room temperature. At this time, when the average particle diameter of a part of the contents was measured by a dynamic light scattering method (DLS), it was 1.72 μm. Next, the polymerization initiator and residual monomer were removed by a centrifuge and purification was performed. Centrifugation was performed at 25 ° C. and 15000 rpm for 20 minutes. After removing the supernatant by decantation, the solid was redispersed with heptane (about 100 mL). This purification operation was repeated three times to obtain a resin fine particle dispersion. Thereafter, a part of the sample was collected and freeze-dried, and the resin fine particles obtained were observed with a scanning electron microscope (SEM). The measurement result of DLS and the observation result of SEM are shown in FIG. 2A shows the measurement result of DLS, and FIG. 2B shows the observation result of SEM. The average particle size of the resin fine particles observed by SEM was 1.65 μm.

[Preparation of metal and resin composite dispersion (A)]
Into a 250 mL sample tube, 36.0 mL of resin fine particle dispersion and 37.7 mL of heptane were added, 0.394 g (2.31 × 10 ⁻³ mol) of silver nitrate, 0.800 g of polyvinylpyrrolidone, and 0.450 g of glucose as a reducing agent ( 2.50 × 10 ⁻³ mol) dissolved in 10 mL of water is added, and the contents are stirred with a homogenizer (25 ° C., 24000 rpm, 35 minutes), so that a metal and a resin comprising a w / o-type pickering emulsion A composite dispersion (A) was obtained. During the stirring, the liquid color changed from white to brown. When the obtained w / o-type pickering emulsion was observed with an optical microscope, a spherical structure of the w / o-type pickering emulsion was observed, and the average particle size was 49.1 μm. However, no silver fine particles were observed. Since the liquid color is changed during the stirring, the reduction of silver is considered to occur, and the particle size of the silver particles is considered to be a nano-region size that cannot be observed with an optical microscope. An image observed with an optical microscope is shown in FIG. The obtained w / o pickering emulsion was stable for 3 weeks.

[Preparation of metal and resin composite dispersion (B)]
W / o type Pickering emulsion in the same procedure as the preparation of the above metal and resin composite dispersion (A) except that the amount of silver nitrate was changed to half (0.197 g, 1.16 × 10 ⁻³ mol). A metal / resin composite dispersion (B) was obtained. During the stirring, the liquid color changed from white to brown. When the obtained w / o-type pickering emulsion was observed with an optical microscope, the spherical structure of the w / o-type pickering emulsion was observed, and the average particle size was 45.1 μm. However, no silver fine particles were observed. Similar to the preparation of the metal / resin composite dispersion (A), the liquid color changed during stirring, so it is considered that silver reduction occurred, and the particle size of the silver particles could not be observed with an optical microscope. It is thought to be the size of the nano-region. The obtained w / o pickering emulsion was stable for 3 weeks.

[Preparation of metal and resin composite dispersion (C)]
W / o in the same procedure as in the preparation of the metal and resin composite dispersion (A) except that ascorbic acid (0.612 g, 3.48 × 10 ⁻³ mol) was used as the reducing agent instead of glucose. A resin composite dispersion (C) comprising a type pickering emulsion was obtained. During stirring, the liquid color changed from white to dark gray. When the obtained w / o-type pickering emulsion was observed with an optical microscope, a spherical structure of the w / o-type pickering emulsion was observed, and the average particle size was 49.7 μm. Silver particles were observed only in the aqueous phase portion of the w / o pickering emulsion, and the particle size was 16.0 μm. An image observed with an optical microscope is shown in FIG. The obtained w / o-type pickering emulsion was stable for 2 weeks.

[Measurement of diffuse reflectance of metal-containing resin films]
About each of metal and resin compound dispersion liquid (A)-(C), the sample slide glass apply | coated to the slide glass and air-dried was produced. On the surface of the sample slide glass, a metal-containing resin film derived from the w / o pickering emulsion containing metal fine particles is formed. About each of the produced sample slide glass, the black felt was mounted | worn behind and the diffuse reflectance was measured at room temperature 15-20 degreeC. The result is shown in FIG. “(A)” in FIG. 5 is the diffuse reflectance of the metal-containing resin film prepared from the metal and resin composite dispersion (A), and “(B)” is from the metal and resin composite dispersion (B). “(C)” is the diffuse reflectance of the metal-containing resin film prepared from the metal and resin composite dispersion (C), and “Black felt” is black. It is a diffuse reflectance only of felt.

  As shown in FIG. 5, it was confirmed that the metal-containing resin film prepared from the metal prepared using glucose as a reducing agent and the resin composite dispersion transmits infrared light while transmitting visible light. Moreover, the metal-containing resin film prepared from the metal and resin composite dispersion prepared using ascorbic acid as a reducing agent reflected both visible light and infrared rays. From the above results, it was shown that the metal and resin composite dispersion of the present invention is useful for preparing a simple infrared reflective film.

Claims (11)

  A dispersion liquid in which a fine sphere formed by collecting resin fine particles contains an aqueous phase, and the sphere is dispersed in an organic phase to form a w / o-type pickering emulsion, wherein a metal is contained in the aqueous phase. A metal and resin composite dispersion characterized by containing fine particles.   The metal / resin composite dispersion according to claim 1, wherein the metal forming the metal nanoparticles is at least one selected from the group consisting of gold, silver, platinum, palladium, rhodium, and copper.   The metal / resin composite dispersion according to claim 1, wherein the resin fine particles are at least one selected from the group consisting of a polymer of an acrylic ester and a polymer of a methacrylate.   A thermal barrier coating comprising the metal and resin composite dispersion according to claim 1.   The manufacturing method of the metal containing resin film characterized by including the process of apply | coating the metal and resin composite dispersion liquid of any one of Claims 1-3.   A method for producing an infrared reflecting film, comprising a step of forming a metal-containing resin film by the method according to claim 5. An addition step of adding a metal ion-containing aqueous solution and resin fine particles into the oil phase to obtain a mixture;
An emulsification step of forming a w / o pickering emulsion by making the mixture obtained in the addition step into an emulsified state under high shear,
Furthermore, the manufacturing method of the metal and resin composite dispersion provided with the reduction | restoration process which reduces the said metal ion to make a metal particle.   The method for producing a metal / resin composite dispersion according to claim 7, wherein the reduction step is performed before or simultaneously with the emulsification step.   The method for producing a metal / resin composite dispersion according to claim 7 or 8, wherein the reduction in the reduction step is performed using ascorbic acid or aldose as a reducing agent.   The method for producing a metal / resin composite dispersion according to claim 9, wherein the aldose is glucose. A method for producing an infrared reflecting film, comprising a step of applying the metal and resin composite dispersion obtained by the production method according to any one of claims 7 to 10 and drying the coating film obtained thereby. .