JP2017197673A - Method for producing emulsion coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion coating material capable of forming a coating film excellent in hydrophilicity and stain resistance.SOLUTION: A method for producing an emulsion coating material includes: a step of mixing an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound to prepare a suspension of precursor particles of an inorganic silicate polymer; a step of removing salt of a by-product from the suspension of the precursor particles of the inorganic silicate polymer; a step of subjecting the suspension of the precursor particles of the inorganic silicate polymer from which salt has been removed to a hydrothermal reaction to obtain a suspension of inorganic silicate polymer particles; and a step of mixing the suspension of the inorganic silicate polymer particles and resin emulsion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an emulsion paint and a method for forming a coating film.

  Paints are usually applied to the surface of various materials, products, and parts with a film thickness of several to hundreds of μm. In addition to protecting the substrate (prolonging the service life), depending on the application , Their functions are demonstrated by giving them a color, texture, gloss and radiance. The main functions of the coating are aesthetics and protection of the object. One of the important functions of the coating film is the durability that keeps the aesthetic appearance with sub-millimeter order film thickness and protects the object to be coated from harsh environment for a long time.

  The coating film is always exposed to some form of contact with the outside world, and is subjected to natural exposure due to ultraviolet light, rainfall, etc., and strong physical and chemical attack of human factors. The performance of the coating will be determined by how durable it is to various external stimuli including these external environmental factors. For this reason, the durability evaluation test is performed on all machines and structures used outdoors such as automobiles, civil engineering machinery, large steel structures such as bridges and storage tanks, and large public buildings such as buildings and gymnasiums. It is used as an important criterion for evaluating the overall performance of the system.

  With the development of petrochemistry since the 1960s, research fields of resin synthesis and polymer chemistry have advanced, and research and development of materials with excellent weather resistance have been conducted. Furthermore, in recent years, in addition to conventional weather resistance, there has been competition for technological development of coating films having stain resistance, and the market needs are extremely high. In particular, buildings in recent years have been increasing in height and design, and there are many cases in which re-coating is difficult because the coating film is easily contaminated. In particular, it has been a problem that rain streaks are formed in which contaminants attached to the wall surface are formed along with the flow of rainwater, and the aesthetic appearance is impaired.

  Thus, there is an increasing demand for paints that reduce the occurrence of rain streak and enable the aesthetics of a building to be maintained over a long period of time. One of the methods attracting attention in recent years is to make the surface of the coating film hydrophilic. This is a method of making the surface of the coating film hydrophilic to prevent adhesion of highly hydrophobic contaminants and facilitating the removal of contaminants by diffusing rainwater to the surface.

  Attempts have been made to paint a paint containing a photocatalyst on a base material such as a wall material to exhibit the photocatalytic function. The coating film formed with such a paint can decompose contaminants adhering to the surface with the catalytic ability of the photocatalyst, and the hydrophilic photocatalyst is exposed on the surface of the coating film, so that dirt adheres to it. Demonstrate that it is difficult. Therefore, the coating film containing a photocatalyst has a self-cleaning function for removing dirt by itself.

  However, when an organic paint containing a resin is used, since the resin comes into contact with the photocatalyst, there is a problem that the resin is decomposed by the catalytic action and the coating film is deteriorated. In view of these points, it is desired to construct a coating film that exhibits hydrophilicity and stain resistance without using a photocatalyst.

  In general, the presence of colloidal silica is known as an inorganic dispersion stabilizer for paints. Currently, research is being conducted on a technique for imparting stain resistance by making a coating film hydrophilic.

  For example, Patent Document 1 discloses colloidal silica containing a group of non-spherical irregularly shaped silica particles in which urea is immobilized inside the particles.

  Patent Document 2 discloses colloidal silica composed of silica particles in which ε-caprolactam is immobilized inside the particles.

  Patent Document 3 contains polyvinylpyrrolidone, has a major axis / minor axis ratio in the range of 1.2 to 15 by observation with a transmission electron microscope, and an average value of the major axis / minor axis ratio is 1.5 to 10. Colloidal silica containing non-spherical irregularly shaped silica particles is disclosed. Here, colloidal silica is produced using activated silicic acid as a raw material in the presence of polyvinylpyrrolidone.

  Patent Document 4 discloses (A) a hydrophilic resin composition and a hydrophilic resin composition containing a Diels-Alder reaction product of maleic anhydride and unsaturated fatty acid, (B) a basic compound, and (C) an inorganic filler. An aqueous coating composition containing is disclosed.

Patent Document 5 discloses the use of a binder system comprising a compound containing aluminum oxide and silicon oxide for producing hydrophilic building materials. Here, the sum of the oxides calculated as Al ₂ O ₃ and SiO _{2 in the} binder system is 40% by weight or more based on the anhydrous binder system and placed on the surface of the cured building material. The contact angle of the oil droplets is 90 ° or more. At that time, the contact angle is measured in water.

JP 2011-42522 A JP 2009-184855 A JP 2013-227177 A JP 2010-275410 A Special table 2013-537163 gazette

  However, Patent Documents 1 to 3 focus only on the shape of colloidal silica, and do not focus on the exposure amount and composition of hydroxyl groups on the surface, and have a single composition.

  Moreover, in patent document 4, the influence which the (B) basic compound required for reaction and a by-product have on the coating-material matrix used in various scenes is not considered.

  Further, Patent Document 5 merely uses the surface characteristics of existing aluminum oxide and silicon oxide.

  Therefore, many of these coating compositions depend on the surface characteristics of silica and the affinity of organic compounds with the coating matrix, and it is possible to develop new coatings and coatings that can solve these problems. It was strongly requested.

  In order to obtain high hydrophilicity on the surface, it is desirable to use a solid having a high specific surface area and mesopores, and it is also possible to control the charge distribution of the solid matrix. For example, as a weathered mineral of volcanic ejecta, silicate groups produced in the Earth's surface layer have a high specific surface area and pore volume due to the fine structure resulting from their unique shape, and have a selective ion exchange capacity. Is clear.

  Under such circumstances, the present inventors have made the surface of the coating film hydrophilic without using an existing photocatalytic material in view of the above prior art, reducing the adhesion of contaminants, and being resistant to contamination. With the goal of developing a coating film that excels at high quality, we conducted extensive research.

  As a result, the present inventors obtained a suspension of inorganic silicate polymer particles as a porous material useful as an environmentally friendly material by utilizing a hydrothermal reaction without using a photocatalytic material. After that, the inventors have found a novel finding that it can be mixed with a resin emulsion and applied as an emulsion paint having excellent hydrophilicity and stain resistance, and the present invention has been completed.

  An object of one embodiment of the present invention is to provide an emulsion paint capable of forming a coating film excellent in hydrophilicity and stain resistance.

  One aspect of the present invention is a method for preparing an emulsion paint manufacturing method in which an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound are mixed to prepare a suspension of inorganic silicate polymer precursor particles; Removing a by-product salt from the suspension of precursor particles of the silicate polymer, and hydrothermal reaction of the suspension of precursor particles of the inorganic silicate polymer from which the salt has been removed. A step of obtaining a suspension of inorganic silicate polymer particles, and a step of mixing the suspension of inorganic silicate polymer particles with a resin emulsion.

  According to one embodiment of the present invention, an emulsion paint capable of forming a coating film having excellent hydrophilicity and stain resistance can be provided.

2 is an atomic force micrograph of allophane particles. It is the photograph of the test piece (aluminum board) exposed outdoors for 2.5 months. It is the photograph of the test piece (aluminum plate) exposed outdoors for 6 months.

  Next, the present invention will be described in more detail.

(Method for producing emulsion paint)
The method for producing an emulsion paint comprises mixing an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound to prepare a suspension of inorganic silicate polymer precursor particles, and an inorganic silicate polymer precursor. The step of removing the salt of the by-product from the suspension of particles and the hydrothermal reaction of the suspension of precursor particles of the inorganic silicate polymer from which the salt has been removed result in inorganic silicate polymer particles And a step of mixing a suspension of inorganic silicate polymer particles and a resin emulsion. Thereby, the coating film which is excellent in hydrophilicity and stain resistance can be formed.

  The inorganic silicate polymer particles have a porous structure whose surface is covered with a hydrophilic group (aluminol group and / or silanol group).

The BET specific surface area of the inorganic silicate polymer particles is preferably 200 m ² / g or more, and more preferably 300 m ² / g or more. When the specific surface area of the inorganic silicate polymer particles is 200 m ² / g or more, the exposure ratio of hydroxyl groups on the surface of the inorganic silicate polymer particles is improved, and the inorganic silicate polymer particles in water The dispersibility of can be improved. The specific surface area of the inorganic silicate polymer particles is usually 400 m ² / g or less.

  The particle size of the inorganic silicate polymer particles is preferably in the range of 0.01 to 100 μm, and more preferably in the range of 0.1 to 10 μm.

  The silicon compound is not limited as long as it is monosilicic acid or a derivative thereof, and examples thereof include sodium orthosilicate, alkyl orthosilicate, sodium metasilicate, amorphous colloidal silicon dioxide (aerosil, etc.) and the like. One type or two or more types can be used in combination.

  The aluminum compound is not limited as long as it can generate aluminum ions in an aqueous solution. For example, aluminum such as aluminum chloride, aluminum nitrate, sodium aluminate, aluminum hydroxide, aluminum isopropoxide An alkoxide etc. are mentioned and it can use combining 1 type (s) or 2 or more types.

  The concentration of the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is preferably 1 mmol / L to 10 mol / L, and more preferably 20 mmol / L to 0.5 mol / L. Thereby, the production | generation of a by-product can be suppressed.

  When preparing a suspension of inorganic silicate polymer precursor particles, it is preferable to rapidly mix an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound. Thereby, the production | generation of a by-product can be suppressed.

  Further, when preparing a suspension of inorganic silicate polymer precursor particles, an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound may be mixed simultaneously.

  The speed at the time of simultaneously mixing the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is preferably 1 mL / min to 10000 L / min, and more preferably 1 mL / min to 50 L / min. Thereby, the production | generation of a by-product can be suppressed.

The molar ratio of silicon to aluminum in preparing the suspension of inorganic silicate polymer precursor particles is preferably 0.1 to 5.0, and preferably 0.5 to 3.0. Is more preferable. Thereby, the pore structure of the inorganic silicate polymer particles can be controlled. Suppressing the formation of boehmite (α-AlO (OH)) or gibbsite (α-Al (OH) ₃ ) as a by-product when the molar ratio of silicon to aluminum is 0.1 or more. In addition, by being 5.0 or less, it is possible to suppress the generation of amorphous silica as a by-product.

  The pH of the liquid obtained by mixing the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is preferably 3-8, and more preferably 6-8. Thereby, the chemical composition of the inorganic silicate polymer particles can be controlled.

  In order to adjust the pH of the mixture of the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound, an acid component is added to the aqueous solution of the aluminum compound in advance, or an alkaline component is added to the aqueous solution of the silicon compound in advance. It is also effective.

  Examples of the acid component include hydrochloric acid, nitric acid, sulfuric acid and the like.

  Examples of the alkali component include sodium hydroxide, potassium hydroxide, calcium hydroxide and the like.

  At this time, a reagent such as polyethylene glycol, polyvinyl alcohol, or a surfactant may be added as an aggregation inhibitor together with the acid component or the alkali component.

  If the pH of the solution obtained by mixing the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is weakly acidic, the alkaline aqueous solution is dropped at a rate of 0.1 to 5 mL / min so that the pH is near neutral. In this way, inorganic silicate polymer precursor particles can be produced.

  Examples of the alkaline aqueous solution include aqueous solutions of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, and the like.

  Of course, inorganic silicate polymer precursor particles are produced even when the pH of the solution obtained by mixing the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is in the range of 6.5 to 8 near neutrality.

  It is preferable to stir or shake before removing the by-product salt from the suspension of inorganic silicate polymer precursor particles.

  The temperature at which the suspension of the inorganic silicate polymer precursor particles is stirred or shaken is preferably 10 to 60 ° C, and more preferably 20 to 40 ° C.

  The time for stirring or shaking the suspension of the inorganic silicate polymer precursor particles is preferably 0.1 to 72 hours, and more preferably 1 to 24 hours.

  The method for removing the salt of the by-product from the suspension of the inorganic silicate polymer precursor particles is not particularly limited, and examples thereof include ultrafiltration and centrifugation.

  After removing the by-product salt from the inorganic silicate polymer precursor particle suspension, add approximately the same amount of water as the inorganic silicate polymer precursor particle suspension. It is preferable to disperse.

  In order to control the form of the inorganic silicate polymer particles, an acidic aqueous solution may be added to the suspension of the inorganic silicate polymer precursor particles from which the salt has been removed, if necessary.

  The pH of the suspension of inorganic silicate polymer precursor particles to which an acidic aqueous solution has been added is preferably 3 to 6, and more preferably 3.5 to 4.5.

  Examples of the acidic aqueous solution include aqueous solutions of hydrogen chloride, sulfuric acid, nitric acid, acetic acid, perchloric acid, and the like.

  Hydrothermal reaction of a suspension of inorganic silicate polymer precursor particles from which salt has been removed can produce inorganic silicate polymer particles with controlled chemical composition and pore structure. it can.

  The temperature at which the suspension of the inorganic silicate polymer precursor particles from which the salt has been removed is hydrothermally reacted is preferably 20 to 150 ° C, and more preferably 40 to 105 ° C.

  The time for hydrothermal reaction of the suspension of inorganic silicate polymer precursor particles from which the salt has been removed is preferably 12 to 240 hours, and more preferably 24 to 72 hours.

  At this time, it may be heated and matured in such a way that moisture does not evaporate. For example, a closed vessel such as an autoclave, a mantle heater with a cooling pipe, or the like can be used as a reaction apparatus.

  A suitable condition for hydrothermal reaction of the suspension of inorganic silicate polymer precursor particles from which the salt has been removed is about 100 ° C. and about 48 hours.

  The resulting suspension of inorganic silicate polymer particles may be used as it is, or may be used after being washed several times with water.

  Further, the pH may be adjusted to about 8 to 12 by adding an alkaline aqueous solution to the suspension of inorganic silicate polymer particles, and the product may be aggregated and recovered as a gel substance.

  Examples of the alkaline aqueous solution include aqueous solutions of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, and the like.

  When an aggregation inhibitor is added, it may be extracted and removed in an organic solvent at 200 ° C. or lower for 1 hour or longer. Examples include methanol, ethanol, acetone, toluene, xylene, and benzene.

  In the present embodiment, an amorphous or quasicrystalline material of an allophane precursor or a derivative thereof may be used as a precursor of the inorganic silicate polymer. Thereby, hollow spherical allophane particles can also be synthesized as inorganic silicate polymer particles.

  By controlling the reaction conditions and the molar ratio of silicon to aluminum as described above, inorganic silicate polymer particles with varying physical properties can be synthesized.

  Next, an example of conditions for synthesizing allophane particles as inorganic silicate polymer particles is shown.

  For example, a 100 mmol / L sodium orthosilicate aqueous solution and a 100 mmol / L aluminum chloride aqueous solution are prepared. Each is weighed so that the molar ratio of silicon to aluminum is 0.75, and an aqueous sodium orthosilicate solution is added to the aqueous aluminum chloride solution. At this time, the pH of the mixed solution is desirably about 5 to 7, and the suspension is sufficiently stirred to form a suspension of the precursor of allophane. In order to control the pH of the mixed solution, an inorganic acid aqueous solution or an inorganic base aqueous solution may be added in advance. When the mixed liquid moves to the acidic side, it changes to a transparent aqueous solution. After that, when an aqueous sodium hydroxide solution is added at about 1 ml / min and the pH is adjusted to around 6-7, allophane precursor particles Produces. At the same time as the allophane precursor particles are produced, sodium chloride is produced. Therefore, the sodium chloride is removed by centrifugation or the like, and the suspension of allophane precursor particles is washed. Thereafter, a suspension of allophane particles is obtained by a hydrothermal reaction at 100 ° C. for 48 hours using an autoclave.

  FIG. 1 shows an atomic force micrograph of the obtained allophane particles. A large number of aggregates of massive spherical allophane particles are confirmed from the arrows in FIG.

The obtained allophane particles have a specific surface area of 409 m ² / g, and in the X-ray diffraction pattern, only a broad peak derived from amorphous silicate is confirmed.

  The surface properties and physical properties of allophane particles are controlled by the molar ratio of silicon to aluminum, the concentration of sodium orthosilicate aqueous solution and aluminum chloride aqueous solution, and the concentration of the suspension of allophane precursor particles.

  In this embodiment, the inorganic silicate polymer particles control the porosity and pore size distribution and shape by changing the composition of the precursor of the inorganic silicate polymer, the temperature and time of the hydrothermal reaction. can do. When the concentration of the aqueous solution of the silicon compound or the aqueous solution of the aluminum compound, the temperature of the hydrothermal reaction, or the time is decreased, a thin-film inorganic silicate domain is generated. On the other hand, when the concentration of the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound, the temperature and time of the hydrothermal reaction are increased, the inorganic silicate domain can be enlarged.

  In the present embodiment, the inorganic silicate polymer particles have a porous structure in which the surface is covered with a silanol group or an aluminol group that is a hydrophilic group, and the surface has pores. Extremely hydrophilic.

  In addition, even when a suspension of inorganic silicate polymer particles and a resin emulsion are mixed, the portion in contact with the resin is an inactive ceramic material that is different from the photocatalyst, thus suppressing the decomposition of the resin. can do.

  Although it does not specifically limit as a form of the emulsion coating material of this embodiment, Paints, such as uneven patterns, such as transparent clear, coloring clear, enamel, a lysine tone, and various patterns, such as a spatter tone, are mentioned.

  The resin constituting the resin emulsion is not particularly limited as long as it can be applied to emulsion paints. For example, acrylic resin, silicone resin, acrylic silicone resin, epoxy resin, vinyl acetate resin, urethane resin, styrene resin And synthetic resins such as fluororesin. Of these, acrylic silicone resins are preferred.

  The content of the silicone component in the acrylic silicone resin is preferably 1 to 60% by mass, and more preferably 5 to 40% by mass. When the content of the silicone component in the acrylic silicone resin is 1% by mass or more, the weather resistance of the coating film can be improved. On the other hand, when the content of the silicone component in the acrylic silicone resin is 60% by mass or less, when the emulsion paint is repeatedly applied, the emulsion paint is likely to adhere to the previously formed coating film. The film is difficult to break.

  The mass ratio of the inorganic silicate polymer particles to the solid content of the resin emulsion is preferably 0.01 to 0.50, more preferably 0.10 to 0.50, and 0.15 to 0 Particularly preferred is .50. When the mass ratio of the inorganic silicate polymer particles to the solid content of the resin emulsion is 0.01 or more, the hydrophilicity of the coating film can be improved. On the other hand, when the mass ratio of the inorganic silicate polymer particles to the solid content of the resin emulsion is 0.50 or less, the water resistance of the coating film can be ensured.

  The solid content concentration of the emulsion paint is preferably 2 to 70% by mass, more preferably 2 to 60% by mass, and particularly preferably 3 to 50% by mass. Thereby, the film forming property of a coating film can be improved.

  The emulsion paint may contain a film-forming aid as required.

  Examples of film-forming aids include ethylene glycol ether modified products such as ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether. Examples include propylene glycol ether-modified products, texanol and the like.

  In addition, emulsion paints can be used as needed, such as antifoaming agents, thickeners, freeze inhibitors, wetting agents, water-soluble resins, penetration aids, preservatives, surface conditioners, gelling agents, UV absorbers, oxidation agents. Additives such as inhibitors, coloring pigments, extender pigments, brightness pigments, heat-shielding pigments, photocatalyst pigments, and other pigments, cold water stones, colored stones, colored resin chips, and other design materials that are incompatible with emulsion paints Good.

  According to the method for producing an emulsion paint of the present embodiment, inorganic silicate polymer particles can be produced easily, so that the productivity is good, and even when the emulsion paint is used, the resin is not aggregated. Suppressed and excellent in storage stability. In addition, the coating film formed by emulsion paint has a hydrophilic surface, and it is difficult for contaminants such as soot and dirt to adhere to it. And can retain aesthetics. Furthermore, since the deterioration of the resin can be reduced, the coating film is stable.

(Formation method of coating film)
The method for forming a coating film includes a process for producing an emulsion paint by a method for producing an emulsion paint, and a process for forming the paint film by applying the emulsion paint to an object to be coated.

  The film thickness of the coating film is 1 to 300 μm, preferably 1 to 200 μm, and more preferably 3 to 100 μm. If the thickness of the coating film is less than 1 μm, the strength of the coating film cannot be ensured and cracks may occur. On the other hand, if the coating film thickness exceeds 300 μm, the inorganic silicate polymer particles cannot be sufficiently present in the surface layer portion of the coating film, and the effect of improving the stain resistance of the coating film is insufficient. There is a case.

  As a method for applying the emulsion paint, for example, a known method such as a brush, a roller, an air spray, or an airless spray can be used.

  In order to make the film thickness uniform, the emulsion paint may be applied multiple times.

  Moreover, after apply | coating an emulsion coating material to a coating object, you may dry naturally and you may heat-dry as needed.

  Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples. In addition, a part means a mass part.

(Preparation of suspension of inorganic silicate polymer particles)
A 100 mmol / L sodium orthosilicate and aluminum chloride aqueous solution was prepared. Next, a sodium orthosilicate aqueous solution and an aluminum chloride aqueous solution were rapidly mixed at room temperature so that the molar ratio of Si to Al was 2.0 and stirred for 1 hour. At this time, since the pH was basic of 7 or more, the pH was adjusted to 7 using 1 mol / L hydrochloric acid to obtain a suspension of inorganic silicate polymer precursor particles. The suspension was stirred at 20 ° C. for 1 hour to fully complete the precursor formation reaction. Using a centrifuge, thoroughly wash the suspension of inorganic silicate polymer precursor particles with deionized water to remove by-product salts, and then the inorganic silicate polymer precursor. The same amount of deionized water as the particle suspension was added and well dispersed. A suspension of inorganic silicate polymer precursor particles after washing is sealed in a Teflon (registered trademark) container and heated at 100 ° C. for 48 hours to cause hydrothermal reaction to produce inorganic silicate polymer particles. I let you. Then, after thoroughly washing the inorganic silicate polymer particles with deionized water using a centrifuge, add the same amount of deionized water as the suspension of inorganic silicate polymer precursor particles. Then, a suspension of inorganic silicate polymer particles was obtained by dispersing well. Here, the inorganic silicate polymer includes related compounds obtained from allophane and allophane precursors.

  Using an electric dryer, the inorganic silicate polymer particle suspension was dried at 40 ° C. to obtain inorganic silicate polymer particles.

  Next, the X-ray diffraction pattern, BET specific surface area, and chemical composition of the inorganic silicate polymer particles were measured.

(X-ray diffraction pattern)
The X-ray diffraction pattern of the inorganic silicate polymer particles was measured using an automatic X-ray diffraction apparatus RINT2100V / PC (manufactured by Rigaku Corporation).

  As a result, in the inorganic silicate polymer particles, broad peaks characteristic of amorphous silicate were confirmed around 25 ° and 40 °.

(Specific surface area)
The specific surface area of the inorganic silicate polymer particles was measured by a flow-through nitrogen adsorption method using a catalyst analyzer BELCAT-A (manufactured by Microtrack Bell).

As a result, the inorganic silicate polymer particles had a specific surface area of 228 m ² / g.

(Chemical composition)
The chemical composition of the inorganic silicate polymer particles was measured using a fluorescent X-ray analyzer MESA-500 (manufactured by Horiba Ltd.).

  Table 1 shows the chemical composition of the inorganic silicate polymer particles.

  From Table 1, it was confirmed that the inorganic silicate polymer particles had a Si / Al molar ratio of 2.06 and were silicon-rich.

(Particle size distribution)
The particle size distribution was measured by a dynamic light scattering method using a particle size distribution measuring apparatus ZETASIZER-3000HSA (manufactured by Malvern Instruments).

  As a result, it was confirmed that the inorganic silicate polymer particles had a particle size distribution curve in which the particle size was distributed in the range of 0.1 μm to 10 μm and a sharp peak was observed around the particle size of 1 μm. The volume average particle diameter of the inorganic silicate polymer particles was 1.2 μm.

  Next, an emulsion paint A was prepared using inorganic silicate polymer particles.

(Preparation of emulsion paint A base)
Acrylic resin emulsion Boncoat VONCOAT CF-6140 (DIC) 70 parts, antifoaming agent BYK-028 (Big Chemie) 1 part, film-forming aid Texanol (Eastman Chemicals) 5 parts, water After 24 parts were mixed, the mixture was stirred and mixed with a dissolver to obtain an emulsion paint A base.

(Example 1-1)
Emulsion paint A base, a suspension of inorganic silicate polymer particles, and water are mixed so that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion is 0.06, Emulsion paint A was obtained.

(Example 1-2)
Emulsion paint A was obtained in the same manner as in Example 1-1 except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.12.

(Example 1-3)
Emulsion paint A was obtained in the same manner as in Example 1-1 except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.18.

(Example 1-4)
Emulsion paint A was obtained in the same manner as in Example 1-1 except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.25.

(Comparative Example 1-1)
Emulsion paint A was obtained in the same manner as in Example 1-1 except that the inorganic silicate polymer particles were not added.

  Next, the appearance and hydrophilicity of the emulsion coating film were evaluated.

(Formation of emulsion coating film A)
The emulsion paint A was applied to a PET film using a 20 mil (1 mil = 25.4 μm) applicator and then cured at room temperature until dry to the touch. Then, it cured at 80 degreeC for 2 days, formed the emulsion coating film A, and obtained the test piece. The film thickness of the emulsion coating film A was 55 μm.

(appearance)
The appearance of the emulsion coating film A was visually confirmed.

(Hydrophilic)
The static contact angle with respect to the water of the emulsion coating film A was measured using the automatic contact angle measuring device OCA35 (manufactured by dataphysics).

  Moreover, the wetness when water was sprayed on the emulsion coating film A by spraying was visually observed to evaluate wettability. In addition, the criteria for determining the wettability of the emulsion coating film A are as follows.

A: Good wettability confirmed B: Good wettability but partially water repellent C: Partial wettability confirmed D: High water repellency, no wettability confirmed Table 2 The external appearance and hydrophilicity evaluation result of the emulsion coating film A are shown.

  From Table 2, it was confirmed that the emulsion coating film A of Examples 1-1 to 1-4 is formed with a good coating film. Moreover, the big fluctuation | variation was not confirmed by the static contact angle with respect to the water of the emulsion coating film A of Examples 1-1 to 1-4. On the other hand, it became clear that the wettability of the emulsion coating film A of Examples 1-1 to 1-4 was greatly improved. From the correlation between the wettability and emulsion resistance of the emulsion coating film B described later, the emulsion coating film A of Examples 1-1 to 1-4 is considered to be excellent in contamination resistance.

  In this system, it was concluded that the characteristics of the emulsion coating film A were most suitable when the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was 0.18 or more.

  Next, an emulsion paint B was prepared using inorganic silicate polymer particles.

(Preparation of emulsion paint B base)
A mixture (a) of 55 parts of an acrylic resin emulsion Boncoat VONCOAT CF-6140 (manufactured by DIC) and 25 parts of a 1.5% by weight aqueous solution of a nonionic guar rubber derivative (0.23 parts in terms of solid content) Got ready.

  Separately, a mixed liquid (b) of 3 parts of titanium white, 2 parts of an anionic polymer dispersant Orotan 731 (manufactured by Nippon Acrylic Chemical Co., Ltd.) and 15 parts of water as a coloring pigment was prepared.

  The mixture (b) was added to the mixture (a) and stirred to obtain an emulsion (c).

  To 40 parts of a 4% by weight aqueous solution of magnesium silicate hydrate, 5 parts of a 5% by weight aqueous solution of ammonium biborate and 30 parts of a 1% by weight aqueous solution of sodium carboxymethylcellulose were added, stirred and mixed, and then 25 parts of water was added. In addition, it was diluted to obtain a dispersion medium (d).

  40 parts of the dispersion medium (d) and 60 parts of the emulsion (c) were stirred with a dissolver to obtain a colored pigment suspension (e).

  40 parts of acrylic resin emulsion Boncoat VONCOAT SA-6360 (manufactured by DIC), 57 parts of colored pigment suspension (e), 1 part of an alkali-soluble thickener SN thickener 636 (manufactured by San Nopco), One part of a 25% by mass aqueous ammonia solution and one part of water were mixed and stirred with a dissolver to obtain an emulsion paint B base.

(Example 2-1)
Emulsion paint B base, a suspension of inorganic silicate polymer particles, and water are mixed so that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion is 0.18, Emulsion paint B was obtained.

(Example 2-2)
Emulsion paint B was obtained in the same manner as in Example 2-1, except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.35.

(Example 2-3)
Emulsion paint B was obtained in the same manner as in Example 2-1, except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.50.

(Comparative Example 2-1)
Emulsion paint B was obtained in the same manner as in Example 2-1, except that the inorganic silicate polymer particles were not added.

  Next, the stain resistance and hydrophilicity of the emulsion coating film were evaluated.

(Formation of emulsion coating film B)
Emulsion paint B was spray-applied on an aluminum plate so that the amount applied was 0.45 kg / m ² and cured at room temperature for 17 hours. Then, it cured at 50 degreeC for 72 hours, formed the emulsion coating film B, and obtained the test piece.

(Contamination resistance)
When the test piece was exposed to the outdoors for 2.5 months, the degree of soiling of the rain streaks formed on the emulsion coating film B was visually observed. In addition, the criteria for determining the contamination resistance of the emulsion coating film B are as follows.

A: Rain stains are hardly observed B: Light rain stains are observed C: Dark rain stains are noticeable (hydrophilic)
The static contact angle with respect to the water of the emulsion coating film B was measured using the automatic contact angle measuring device OCA35 (manufactured by dataphysics).

  Moreover, the wetness when water was sprayed on the emulsion coating film B by spraying was visually observed to evaluate the wettability. In addition, the criteria for determining the wettability of the emulsion coating film B are as follows.

A: good wettability is confirmed B: wettability is good but partially water repellent C: wettability is partially confirmed D: water repellency is high and wettability is not confirmed Table 3 The evaluation results of stain resistance and hydrophilicity of the emulsion coating film B are shown.

  FIG. 2 shows a photograph of a test piece exposed outdoors for 2.5 months.

  From Table 3 and FIG. 2, it can be seen that the emulsion coating B of Examples 2-1 to 2-3 is excellent in stain resistance and hydrophilicity when compared with the emulsion coating B of Comparative Example 2-1. Specifically, thick rain streak stains were formed on the emulsion coating film B of Comparative Example 2-1. On the other hand, in the emulsion coating film B of Examples 2-1 to 2-3, almost no rain streak was observed. From this, it became clear that the emulsion coating film B of Examples 2-1 to 2-3 exhibited high stain resistance and hydrophilicity.

  From Table 3, the static contact angle with respect to the water of the emulsion coating film B does not change much even when the amount of the inorganic silicate polymer added is increased, but the wettability of the emulsion coating film B is the inorganic silicate. It turns out that it improves with the increase in the addition amount of a polymer | macromolecule.

  From the above, a clear correlation was confirmed between the stain resistance of the emulsion coating film and the wettability. The reason why the rain streak confirmed in the stain resistance of the emulsion coating film B of Examples 2-1 to 2-3 is reduced is clearly different from the behavior of the existing hydrophilic coating film, and is static contact with water. I can't explain just by the corners. That is, it is considered that such a phenomenon is caused by the interface movement mechanism of contaminated droplets such as raindrops falling on the surface of the emulsion coating film.

  From these facts, the emulsion coating film B of Examples 2-1 to 2-3 has a modified surface property, has stain resistance and wettability derived from the inorganic silicate polymer, It became clear that it has a composite function different from the membrane.

(Example 2-4)
Emulsion paint B was obtained in the same manner as in Example 2-1, except that the mass ratio of the inorganic silicate polymer particles to the solid content of the acrylic resin emulsion was changed to 0.20.

(Comparative Example 2-2)
Emulsion paint B was obtained in the same manner as in Example 2-4, except that colloidal silica Adelite AT-50 (manufactured by Adeka) was used in place of the inorganic silicate polymer particles.

(Comparative Example 2-3)
Emulsion paint B was obtained in the same manner as in Comparative Example 2-2 except that the mass ratio of colloidal silica to the solid content of the acrylic resin emulsion was changed to 0.50.

  Next, the stain resistance of the emulsion coating film was evaluated.

(Formation of emulsion coating film B)
Emulsion paint B was spray-applied on an aluminum plate so that the coating amount was 0.45 kg / m ^2, and cured at room temperature for 14 days to form emulsion coating film B, to obtain a test piece.

(Contamination resistance)
When the test piece was exposed to the outdoors for 6 months, the degree of soiling of the rain streaks generated in the emulsion coating film B was visually observed. In addition, the criteria for determining the contamination resistance of the emulsion coating film B are as follows.

A: Little rain streak stains are observed. B: Light rain streak stains are observed. C: Dark rain streak stains are noticeable. Table 4 shows the evaluation results of the stain resistance of the emulsion coating film B.

  FIG. 3 shows a photograph of a test piece exposed outdoors for 6 months.

  From Table 4 and FIG. 3, it can be seen that the emulsion coating B of Examples 2-3 and 2-4 is excellent in stain resistance when compared with the emulsion coating B of Comparative Examples 2-1 to 2-3. Specifically, a thick rain streak stain was generated in the emulsion coating film B of Comparative Example 2-1 to which no inorganic silicate polymer or colloidal silica was added. On the other hand, the rain streak of the emulsion coating film B of Examples 2-3 and 2-4 to which inorganic silicate polymer was added tended to become thinner as the addition amount increased. In the emulsion coating film B of 2-3, no rain streak was observed. From this, it became clear that the emulsion coating film B of Examples 2-3 and 2-4 showed high stain resistance. On the other hand, in the emulsion coating B of Comparative Examples 2-2 and 2-3 to which colloidal silica was added, rain streak was clearly observed, compared with the emulsion coating B of Examples 2-3 and 2-4. This suggests that the stain resistance is low. This is because the relationship between the intermolecular force and gravity on the surface of the emulsion coating film when the contaminated droplets including wettability slide, which cannot be achieved by the hydroxyl group on the surface of the colloidal silica, This is thought to be because the silanol and aluminol groups exposed to the water are exquisitely balanced and consequently controlled. Thus, it became clear that the emulsion coating film B of Examples 2-3 and 2-4 has excellent hydrophilicity and stain resistance that could not be achieved with colloidal silica.

  The emulsion paint of the present embodiment uses the excellent water resistance, heat resistance and corrosion resistance of the added inorganic silicate polymer particles, a unique shape, a drug microcapsule, a water purification filter, etc. It can be used in a wide range of industrial fields. In addition, inorganic silicate polymer particles are also used in pharmaceuticals and cosmetics, and are approved for use as food additives. So it is economical.

  Here, since the hydrophilic property of the surface of inorganic silicate polymer particles lasts for a long time, it can be added as a filler to a medium such as organic fiber or plastics. For this reason, the emulsion paint of this embodiment can be applied to interior spaces such as automobiles and bathrooms.

Claims (12)

Mixing an aqueous solution of a silicon compound and an aqueous solution of an aluminum compound to prepare a suspension of precursor particles of an inorganic silicate polymer;
Removing by-product salts from the suspension of inorganic silicate polymer precursor particles;
A step of hydrothermally reacting a suspension of inorganic silicate polymer precursor particles from which the salt has been removed to obtain a suspension of inorganic silicate polymer particles;
A method for producing an emulsion paint, comprising a step of mixing a suspension of the inorganic silicate polymer particles and a resin emulsion.   The said inorganic silicate polymer | macromolecule contains the related compound obtained from allophane and the allophane precursor, The manufacturing method of the emulsion coating material of Claim 1 characterized by the above-mentioned.   The method for producing an emulsion paint according to claim 1 or 2, wherein the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound each have a concentration of 1 mmol / L to 10 mol / L.   The method for producing an emulsion paint according to any one of claims 1 to 3, wherein a molar ratio of the silicon to the aluminum is 0.1 to 5.0.   The method for producing an emulsion paint according to any one of claims 1 to 4, wherein the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound are rapidly mixed at 1 mL / min to 10000 L / min.   The method for producing an emulsion paint according to any one of claims 1 to 5, wherein the pH of the liquid obtained by mixing the aqueous solution of the silicon compound and the aqueous solution of the aluminum compound is 3 to 10. A step of stirring the suspension of the inorganic silicate polymer precursor particles at 10 to 50 ° C. for 0.1 to 72 hours;
The emulsion paint production according to any one of claims 1 to 6, wherein the salt of the by-product is removed from the stirred suspension of inorganic silicate polymer precursor particles. Method.   8. The emulsion paint according to claim 1, wherein the suspension of precursor particles of the inorganic silicate polymer is hydrothermally reacted at 20 to 150 ° C. for 12 to 240 hours. Production method. The method for producing an emulsion paint according to any one of claims 1 to 8, wherein the inorganic silicate polymer particles have a specific surface area of 200 m ² / g or more.   The method for producing an emulsion paint according to any one of claims 1 to 9, wherein the inorganic silicate polymer particles have a particle size in a range of 0.01 to 100 µm.   The mass ratio of the said inorganic silicate polymer particle with respect to solid content of the said resin emulsion is 0.01-0.50, The manufacture of the emulsion coating material as described in any one of Claims 1 thru | or 10 characterized by the above-mentioned. Method. A step of producing an emulsion paint by the method of producing an emulsion paint according to any one of claims 1 to 11,
A method for forming a coating film, comprising the step of applying the emulsion paint to an object to be coated to form a coating film having a thickness of 1 to 300 μm.