KR20100083617A - Manufacture method of aquous suspension and composition - Google Patents

Abstract

The present invention is composed of an aqueous dispersion composed of composite particles composed of colloidal silica as a core and an organic polymer as a cell, a manufacturing method thereof, and an aqueous dispersion, which has high film forming property and stain resistance, and is capable of adjusting gloss and mechanical properties. It relates to a composition.

  In particular, the use of inorganic silica and the like is a useful invention that can reduce the amount of organic materials and improve the mechanical properties to reduce the cost and quality of the product.

Description

Aqueous dispersion, preparation method thereof, and coating composition {Manufacture method of aquous suspension and composition}

The present invention is to provide an aqueous dispersion having a high film stability and storage stability, and having a high solid content, and a method for producing the same, and an aqueous dispersion having excellent properties that are economically advantageous without using a special silane compound and its It is to provide a manufacturing method. In particular, the present invention provides an aqueous dispersion containing a colloidal silica as a core and a core / shell state composite having a core as an organic polymer and a method for producing the same. Another object of the present invention is to provide a method for producing an aqueous dispersion in which the production amount of both polymer alone and the surface coating amount of both colloidal silica can be controlled. Therefore, it is possible to provide a coating composition having good film forming properties, stain resistance and weather resistance, and to provide a coating composition capable of adjusting the excess of the coating film without using a gloss removing agent.

The present invention is to provide an aqueous dispersion and a method for producing the film, even if the dispersion stability and storage stability is high, and the solid concentration is high, without the use of a special silane compound, an aqueous dispersion having excellent properties economically advantageous and its production To provide a way. In particular, the present invention provides an aqueous dispersion containing a colloidal silica as a core and a core / shell state composite having both an organic polymer as a shell and a method of manufacturing the same. Another object of the present invention is to provide a method for producing an aqueous dispersion in which the production amount of both polymer alone and the surface coating amount of both colloidal silica can be controlled. Therefore, it is possible to provide a coating composition having good film forming properties, stain resistance and weather resistance, and to provide a coating composition capable of adjusting the gloss of the coating film without using a gloss remover.

In general, colloidal silica is excellent in hardness, mechanical strength, antistatic property, chemical resistance and weather resistance, and an organic polymer is excellent in flexibility and adhesion, and an organic-inorganic composite aqueous composition in which both are combined is known. For example, an aqueous coating agent based on a mixture of a vinyl nitrate emulsion, an acrylate emulsion, a colloidal silica, a hydraulic binder, and the like is known. However, in such an aqueous coating agent, the bonding strength between the organic polymer and the inorganic substance is small, and long term durability, film formability, water resistance, etc. are not sufficient. Moreover, in the coating composition which binders the mixed state of an electrically colloidal silica and an organic polymer, when a large amount of colloidal silica is added, film formation will fall, and the contamination and film formation property of colloidal silica are balanced to a high level well. It is difficult to let. In addition, when gloss removal agents, such as silica and potassium carbonate, are used when adjusting the glossiness of a coating film, water resistance, weather resistance, and mechanical property will fall with the increase of a gloss removal agent.

  An aqueous resin dispersion obtained by copolymerizing a silane monomer and a colloidal silica in order to chemically bond colloidal silica and an organic polymer as an inorganic substance is disclosed. In this dispersion, since a chemical bond is formed between colloidal silica and a silane monomer, the compatibility and familiarity between an inorganic substance and an organic polymer are good, and it is excellent in water resistance, alkali resistance, and pollution resistance. However, the stability of the obtained aqueous dispersion and the coating material is lowered, the coating film is nonuniform, so that the coating film has a high shrinkage and cohesion force, and cracks may occur in the coating film, resulting in difficulty in durability.

  After coupling colloidal silica and organic alcohol keysilane, it is proposed to polymerize vinyl monomer to produce an aqueous dispersion of both core / shell state composites. However, it is difficult to obtain an aqueous dispersion having a solid content of 40% by weight or more when using a colloidal silica of 50 nm or less, which exhibits good strength as a coating film, and the solid content clearly increases in viscosity and is inferior in film formability. In addition, in order to obtain a stable core / shell state complex quantum, it is necessary to use many special silane compounds having a methacryl group, which is disadvantageous in terms of production cost. In addition, the total reaction time is 10 seconds or more, so that the aqueous dispersion and the binder for coating cannot be industrially advantageously produced.

The present inventors pay attention to the charging of both colloidal silica in the aqueous medium by the negative electrode. As a result of intensive investigation, the electrical problem of the present invention in the aqueous medium is to uniformly adsorb cationic radical polymerization active species on the surface of the colloidal silica. When the vinyl monomer was polymerized, both the silica and the vinyl polymer were effectively bonded to each other, and it was found that an aqueous dispersion having high dispersion stability and film formability could be obtained. That is, a composite proton in which a vinyl polymer is bonded to both surfaces of colloidal silica with residues of a cationic polymerization active species called an aqueous dispersion of the present invention is dispersed in an aqueous medium. As the cationic polymerization utilization species, cationic radical polymerization initiators, cationic monomers, cationic vinyl monomers having an interfacial activity, and the like can be used. Vinyl polymers include (meth) acrylic monomers and aromatic vinyl ester monomers. Can form. In such an aqueous dispersion, the average proton diameter of both the electric complexes is about 10 nm to 1 m.

  The electro-aqueous dispersion has (1) cationic radical polymerization initiators, cationic vinyl monomers, and surfactants in an aqueous medium, in the presence of (1) nonionic surfactants, (2) on both colloidal silica surfaces, and It can be prepared by adsorbing at least one radical polymerization activity selected from cationic vinyl monomers, and (4) polymerizing the vinyl monomers. The present invention also discloses a coating composition comprising the electro-aqueous dispersion.

  The composite proton constituting the aqueous dispersion of the present invention is a colloidal silica proton and is composed of a cationic polymer conjugated species bonded to the surface of the silica protons and a vinyl polymer bonded to the electric silica proton surface with residues of the cationic polymer active species. Dispersed in an aqueous medium. Such an aqueous dispersion may normally contain a dispersing agent (especially cationic surfactant).

  As colloidal silica particles (colloidal silica), an anhydrous silicic acid collecting particle colloid (colloid) having an average particle diameter of 5 nm to 1 m, preferably about 10 to 100 m can be used.

  Colloidal silica can be prepared and used by the sol-gel method, and can use a commercial item. When colloidal silica is prepared by the sol-gel method, the colloidal silica may contain silicon, sodium aluminate, or the like as a main component of silicon dioxide. In addition, the colloidal silica may contain inorganic bases (sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, etc.) and organic bases (tetramethyl ammonium, etc.) as stabilizers.

  Such colloidal particles are usually charged with an anode in an aqueous medium. For this reason, in this invention, cationic polymerization active species is used in order to form a cationic polymerization active point in the surface of a silica particle. The cationic polymerization active species is electrostatically adsorbed on the surface of the colloidal silica particles serving as the core to electrostatically hydrophobize both surfaces of the silica to provide a place for polymerization.

  Examples of the cationic polymerization active species include cationic radical polymerization initiators, cationic vinyl monomers having at least one ethylenically unsaturated group, cationic vinyl monomers having at least one ethylenically unsaturated group and having an interfacial activity. These active species can be used individually or in combination of 2 or more types.

  Cationic vinyl monomers are adsorbed on the surface of colloidal silica particles and used for copolymerization with vinyl monomers.

  Cationic vinyl monomers having an interfacial activity can be used for copolymerization with vinyl monomers, such as electric cationic vinyl monomers.

  The amount of cationic polymerization active species to be used is selected according to the surface type of colloidal silica or the like, and is, for example, 0.1 to 20 parts by weight, preferably 0, 5 to 15 parts by weight, and preferably, based on 100 parts by weight of the vinyl polymer. Is about 1 to 10 parts by weight. The amount of the silicic polymerization active species to the colloidal silica particles is 0 to 1 to 20 parts by weight, preferably 0 to 5 to 15 parts by weight, based on 100 parts by weight of the colloidal silica particles in terms of solid content. Preferably it is about 1-10 weight part.

  The vinyl polymer may be formed of a polymerizable monomer of cost and may meet alone or in a copolymer. Monomers forming the vinyl polymer include radically polymerizable monomers having at least one ethylenically unsaturated group such as (meth) acrylic monomers, aromatic vinyl multimers, vinyl ester monomers and the like. These monomers can be used individually or in combination of 2 or more types.

  Preferred vinyl monomers include (meth) acrylic monomers, aromatic vinyl monomers, vinyl ester monomers, and the like. In particular, at least (meth) acrylic monomers are often used. The vinyl monomer may be used in combination with a polyfunctional vinyl monomer having two or more unsaturated groups. Among the polyfunctional vinyl monomers, divinylbenze, monomers having two or more (meth) acrylo groups (ethyleneglycodi (meth) acrylate, and the like) are generally used.

  Moreover, an electric vinyl monomer can be selected according to the characteristic (film forming property, glass transition temperature, etc.) required for film forming, Usually, glass transition temperature is -30-80 degreeC, The preferable thing is -20-50 degreeC, Especially 0-50 degreeCw To a degree of vinyl polymer. Moreover, in order to comprise a crosslinking system, you may use the vinyl monomer which has reactive groups, such as a hydroxyl group, a carboxyl group, an acid anhydride group, and a glycidyl group.

  The ratio between the vinyl polymer and the colloidal silica particles can be selected according to film forming properties and the like. For example, 3 to 500 parts by weight of the colloidal silica particles with respect to 100 parts by weight of the vinyl polymer, and preferably 10 to 300 parts by weight. Moreover, about 20-200 weight part (for example, 30-200 weight part) is preferable.

  The average particle diameter of the composite grain | particle which consists of such a component is 10 nm-1 micrometer, for example, 20-500 micrometers is preferable. In particular, it is about 20-200 nm (for example, 20-100 nm). High dispersion stability of composite particles.

  For the aqueous dispersion, not all of the dispersed particles need to be electric composite particles, but may be a mixture of the composite particles and at least one species selected from vinyl polymer particles and colloidal silica particles. Preferred aqueous dispersions comprise at least 80% by weight of the particles of composite particles of core / shell constitution in which colloidal silica is the core and vinyl polymer is the shell.

  The aqueous dispersion of this invention adsorb | sucks (3) electro radical polymerization active species in the presence of (1) cationic surfactant in the aqueous medium, (2) the surface of an electrocolloidal silica particle, (4) an electric vinyl weight body It can obtain by superposing | polymerizing.

  The use amount of cationic surfactant is 0.1-20 weight part with respect to solid content and 100 weight part of colloidal silica particles, Preferably it is 0.5-15 weight part, Moreover, about 1-10 weight part is preferable. Moreover, the usage-amount of cationic surfactant with respect to 100 weight part of vinyl monomers is 0.1-20 weight part, for example, 5-15 weight part is preferable. Moreover, about 1-10 weight part is preferable.

  In the present invention, cationic polymerization active species are adsorbed onto colloidal silica particles.

  When the cationic polymerization active species is a cationic radical initiator, composite particles can be produced by polymerizing vinyl monomers with the resulting radicals. In addition, when the cationic radical initiator is unstable in a high pH range, the pH is controlled by acid (sulfuric acid, nitric acid, etc.) to polymerize to a high ph7-8 (eg 7.5-8) of dispersion stability of colloidal silica. desirable.

  In order to uniformly adsorb cationic radically polymerized active species to colloidal silica particles charged on the negative electrode, it is preferable to adsorb in a coexistence system of an electric cationic surfactant. Adsorption in the absence of a cationic surfactant causes hydrophobicity as the adsorption of the cationic radically polymerized active species on the silica surface decreases the dispersion stability of the colloidal silica, making it easier to aggregate and gel. Cationic surfactants are oriented to the surface of hydrophobized silica particles by adsorption of radically polymerized active species to stabilize colloidal silica particles or to stably provide a place for polymerization of vinyl monomers.

  In order to adsorb the polymerizable active species more uniformly than the cationic one, an aqueous solution containing an appropriate concentration of the radically polymerized active species (aqueous solution of about 1 to 20% by weight) is stirred in the presence of a cationic surfactant and an aqueous solution containing colloidal silica. It is preferable to add while dropping (for example, dropping in about 15 to 60 minutes). In addition, when the radical polymerization activator is added under non-stirring, or in the gododo or solid state, aggregates may be formed or the stability may be deteriorated, resulting in increased gelling.

  In addition, the use of an anionic interfacial generator generally used in emulsion polymerization causes electrostatic action with an electrocationic radical polymerization activator to inhibit adsorption of the cationic radical polymerization active species on the surface of colloidal silica particles. However, in the presence of a cationic surfactant, in the process of polymerizing the cationic radical polymerization active species and the vinyl monomer, the polymerization reaction is partially progressed and then stabilized seed particles are formed. It is also good to add.

  The amount of the cationic radical polymerization activator can be selected based on the saturation adsorption amount measured in advance according to the type of colloidal silica.

  In the present invention, the vinyl monomer may be polymerized by a method of polymerizable species in an electric dispersion system. Preferred polymerization methods are emulsion polymerization methods which polymerize vinyl monomers in an aqueous medium (particularly water). In emulsion polymerization, the monomers may be immersed in a reaction system in a batch, and the monomers may be added and reacted continuously or stepwise in the reaction system. After the seed particles are produced by emulsion polymerization, a sheet emulsion polymerization method or the like in which a monomer is supplemented and reacted may be employed. Moreover, when adding a monomer continuously or stepwise to a reaction system, the component and composition of a monomer may be the same and may be changed.

  When the cationic radical polymerization active species is a cationic radical initiator, a polymerization initiator is not necessary to polymerize the vinyl monomer, and may be used in combination with the polymerization initiator in a suitable polymerization process (in the initial polymerization stage and after the sheet is formed in the sheet polymerization). You may also As a polymerization initiator, a peroxide (hydrogen peroxide etc.), a persulfate (potassium persulfate, ammonium persulfate etc.), a water-soluble azo compound, a redox polymerization initiator system, etc. are illustrated, for example.

  The ratio of each component of electricity is the same as electricity. For example, (4) 0.1-20 weight part of (1) cationic surfactants, (2) 3-500 weight part of colloidal silica particles, (3) cationic polymerization active species 0.1-20 with respect to 100 weight part of vinyl polymers It can select from the range of about a weight part.

  By this reaction it is possible to produce composite particles of a core / shell configuration. Moreover, in this invention, the ratio of a composite particle / vinyl polymer particle / colloidal silica particle can be arbitrarily controlled by adjusting the ratio and reaction conditions of each component. For example, after adsorbing a radically polymerizable active species (1a) and incorporating the vinyl monomer in the presence of a cationic surfactant below the critical micelle concentration (CMC), an aqueous dispersion containing core / shell structured composite particles as a main component You can get it. (1b) When the critical micelle concentration is exceeded, an aqueous dispersion composed of a mixture of composite particles / vinyl polymer particles can be obtained by polymerizing a vinyl monomer in the presence of a cationic surfactant.

  (1c) When the critical micelle concentration is exceeded, the composite particles are polymerized by using (3) radical polymerization active species in the presence of a cationic surfactant (2) a ratio of five or less molecules on average corresponding to one colloidal silica particle. It is possible to obtain an aqueous dispersion consisting of a three-component mixture of single particles of a vinyl polymer / colloidal silica particles. The said ratio of radical polymerization active species can be selected according to the kind of colloidal silica particle, For example, 0.1-2 weight part of radical polymerization active species with respect to 100 weight part of colloidal silica particles, Preferably 0.3-1.5 weight part In particular, it can be selected in the range of about 0.3 to 1 parts by weight. Aqueous dispersions containing composite particles as a main component are prepared by using radically polymerized active species in an amount exceeding an average of five molecules corresponding to one colloidal silica particle. When it does, the radical polymerization active species 1.5-5 weight part with respect to 100 weight part of colloidal silica particles can be selected in the range of about 2-3 weight part. When producing a composite particle and a colloidal mixture using an average of 1 to 5 molecules or less of a radical polymerization activator corresponding to one colloidal silica particle, 0.1 to 2 radically polymerized active species based on 100 parts by weight of the colloidal silica particle A weight part and a preferable thing can be selected in the range of about 0.3-1 weight part.

  In addition, in this specification, a critical micelle concentration (CMC) means the density | concentration which micelle produces in an aqueous phase when adding a cationic surfactant in presence of colloidal particle | grains. The critical micelle concentration varies depending on the content of colloidal silica particles, electrolyte concentration, and the like, but it is possible to use the concentration of the surface of the critical micelles as an indicator of the critical micelle concentration in relation to the concentration of the critical activator and the surface tension. . For example, the critical micelle concentration of the cationic surfactant is not large when these components are present as compared with the case where the colloidal silica particles and the electrolyte are not present. In the presence of colloidal silica particles and an electrolyte, the critical micelle concentration at which the surface tension is minimized is measured, and the polymerization is performed at a concentration of CMC or less to produce composite particles having a core / shell structure and multimodal polymer particles.

  In the polymerization of the present invention, in order to control the molecular weight of the polymer, a chain transfer agent such as an organic peroxide, an organic azo compound, a halogenated hydrocarbon system (carbon tetrachloride, etc.), metacaptans, thiols, etc., which are soluble in a weight of vinyl is used. Also good. The amount of the chain transfer agent used is, for example, 5% by weight or less based on the vinyl monomer. Solid content concentration of an aqueous dispersion can be selected according to a use etc., for example, 10 to 60 weight%, Preferably it is 30 to 55%, especially about 45 to 55%.

  The aqueous dispersion obtained by this method can form a coating film excellent in high film formability, fouling resistance, heat resistance and the like even when the content of the colloidal silica is 50% by weight. In addition, the ratio of the electrically composite interest / vinyl polymer particles / colloidal silica particles can be controlled, and a high gloss coating film and a gloss removal coating film can be formed. Therefore, the composition composed in the aqueous dispersion of the present invention is useful as a film forming material (coating agent), especially a coating film composition. In addition, if the ratio of the composite particles and colloidal silica is changed in the range of the composite particles / colloidal silica particles = 100/0 to 50/50 (weight ratio in terms of solid content) following the aqueous aqueous dispersion, a gloss remover such as silica is used. Instead, the gloss at the incident angle of 60 ° can be adjusted in the range of about 85 degrees.

The coating composition (aqueous coating composition) of the present invention includes various kinds of components commonly used as aqueous coatings, for example, pigments, dispersants, wetting agents, thickeners, plasticizers, surface conditioners, antifoams, viscosity regulators, heat-retardants, antistatic agents, A water-soluble organic solvent, etc. can be used. Examples of the pigments include colored pigments such as titanium dioxide, iron oxide, and phthalocyanine blue, organic pigments such as calcium carbonate and barium sulfate, and brightening agents such as aluminum acid and mica flakes. The pigment weight concentration (PWC) in the coating composition is usually 1 to 70% by weight, preferably 10 to 65% by weight, and preferably about 20 to 60% by weight in terms of solid content. If solid content concentration is less than 1 weight%, concealability falls, and if it exceeds 70% weight%, glossiness of a coating film will fall, a viscosity will become high, and water resistance and mechanical strength will fall easily.

  In the coating composition, the coating composition containing the composite particles (which also function as a binder) as the main component (80 wt% or more) is colloidal silica 3 to 500 (preferably 50 to 500 parts by weight) based on 100 parts by weight of the vinyl monolayer. It has high film formability in the low range of ()). Excellent pollution resistance and heat resistance. In particular, the coating composition with a high colloidal silica content ratio can express high heat resistance without using a heat-retardant.

  As needed, you may add water-soluble or water-dispersible binder resin, a crosslinking agent, an emulsifier, a crosslinking, or an emulsification adjuvant to the coating composition of this invention. The coating material of this invention can form a highly durable coating film when it apply | coats to a base material by the conventional method, and it dries or hardens.

  In the present invention, since the aqueous dispersion contains the electrical composite particles (particularly, core / shell-shaped composite particles in which organic polymers composed of colloidal silica cores are used as shells), the film-forming properties are high even when the solid concentration is high due to high dispersion stability and storage stability. It is possible to raise. In addition, it is possible to obtain an aqueous dispersion having special properties that are advantageous economically and without using a special silane compound. As the coating composition of the present invention, another object of the present invention is to maintain a high level of fouling resistance and weather resistance which could not be achieved as a film forming property and a conventional water-based coating, and can form a coating film having high durability and high water resistance and weather resistance. have. In addition, the composition having a high composition ratio of the colloidal silica can greatly improve heat resistance and heat resistance without maintaining high film forming properties. In addition, the production amount of the vinyl polymer particles and the surface coverage of the colloidal silica particles can be controlled, and the composition ratio of the composite particle / vinyl polymer particles / colloidal silica particle system can be adjusted. Therefore, the glossiness of a coating film can be adjusted without using a gloss remover.

The present invention is composed of an aqueous dispersion composed of composite particles composed of colloidal silica as a core and an organic polymer as a cell, a manufacturing method thereof, and an aqueous dispersion, which has high film forming property and stain resistance, and is capable of adjusting gloss and mechanical properties. It relates to a composition.

  In particular, the use of inorganic silica, etc. is an invention that can reduce the amount of organic materials and improve the mechanical properties to reduce the cost and quality of the product.

Although the present invention has been described in more detail based on the following synthesis examples, examples, and comparative examples, the present invention should not be limited by these examples.

Synthesis Example 1

A colloidal silica (50 wt% solids), an average particle diameter of 20 to 30 nm and 200 g were placed in a 1000 ml four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube. 3.0 g of product (80%, reactive) is added with stirring. After adjusting to pH7.5-8 with 2N-H2SO4, 2.0 g of 2-2 'asobis (almidino propane) dihydrochloride and 100 g sap of distilled water are dripped at the dropping lot over 30 minutes, stirring at 300 rpm. In addition, 5 g of a vinyl monomer of methyl methacrylate (MMA) / n-butyl acrylate (nBA) / methacrylic acid (MAA) = 49/50/1 (weight ratio) was added dropwise for 10 minutes, and then superheated at 70 ° C. Leave for 30 minutes a year. Then, 0.4 g of peramammonium is added, and 95 g of vinyl weights of MMA / n-BA-MAA = 49/50/1 (weight ratio) are dropped over 4 hours. Maintain the reaction temperature at 70 ° C. and after completion of the dropwise addition, keep the stirring at 70 ° C. for 1 hour to continue stirring. After cooling, the mixture was adjusted to ph 8.5 with 25% ammonia water to obtain 402 g of a composite fine particle dispersion (yield 98%, 40% by weight of solid content, 72 nm in average particle diameter).

Synthesis Example 2

  A colloidal silica (50 wt% solids), an average particle diameter of 20 to 30 nm and 200 g were placed in a 1000 ml four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube. 3.0 g of the product (840S, 70 wt% solids) was added with stirring, and a solution of 4.0 g of cationic monomer (polymer-QA, 50 wt% solids) and 100 g of distilled water was stirred at 300 rpm over 30 minutes with a dropping lot. Dropping In addition, 5 g of vinyl monomer of MMA / nBA-MAA = 49/50/1 (weight ratio) was added dropwise for 10 minutes, heated to 70 ° C., and 0.5 g of potassium persulfate was added and left for 30 minutes. After adding 1.0 g of this anionic surfactant (solid content 25 weight%), 95 g of vinyl monomers of MMA / nBA / MAA = 49/50/1 (weight ratio) are dripped over 4 hours. The reaction temperature is maintained at 70 ° C. and after completion of dropping to maintain the stirring at 70 ° C. for 1 hour. After cooling, the mixture was adjusted to pH 8.5 with 25% ammonia water to obtain 401 g of a composite fine particle dispersion (yield 98%, 50% by weight of solid content, average particle diameter: 65nm).

Synthesis Example 3

  250 g of colloidal silica (solid content 40 wt% average particle diameter 10-20 nm) was placed in a 1000 ml four-necked flask equipped with a stirrer, a thermometer, a dropping lot, and a reflux cooling tube. 3.75 g of NE-20 and 80 wt% solids) are added with stirring, and the solution of 3.0 g of reactive cationic surfactant and 50 g of distilled water is added dropwise over 30 minutes with a dropping lot while stirring at 300 rpm. Moreover, 95 g of vinyl monomers of MMA / nBA / MAA = 49/50/1 (weight ratio) are dripped over 4 hours. The temperature is maintained at 70 ° C, and stirring is continued while maintaining at 70 ° C 1 hour after completion of dropping. After cooling, the mixture was adjusted to pH 8.5 with 25% ammonia water to obtain 400 g of a composite fine particle dispersion (yield 98%, 50% by weight of solid content, 72 nm in average particle diameter).

Synthesis Example 4

  200 g of colloidal silica (50% by weight, average particle diameter: 20-30 nm) was placed in a 1000 ml four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube. 6.25 g of 80% by weight solid content) is added with stirring. After adjusting to pH7.5-8 with 2N-H2SO4, 2.0 g of 2-2 'asobis (almidino propane) dihydrochloride and 100 g sap of distilled water are dripped at the dropping lot over 30 minutes, stirring at 300 rpm. In addition, 5 g of vinyl monomer of MMA / nBA / MAA = 49/50 1 (weight ratio) is added dropwise over 10 minutes, thereafter raised to 70 ° C. and left for 60 minutes. Then, 0.4 g of ammonium persulfate ammonium is added, and 95 g of vinyl monomers of MMA / nBA / MAA = 49/50 1 (weight ratio) are added dropwise over 4 hours. The temperature during the dropping is maintained at 70 ° C. and after completion of the dropwise addition and maintained at 70 ° C. for 1 hour to continue stirring. Cool and operate to pH 8.5 with 25% ammonia water to obtain an aqueous dispersion (50 wt% solids, 48 nm average particle diameter).

Synthesis Example 5

  200 g of colloidal silica (50% by weight, average particle diameter: 20-30 nm) was placed in a 1000 ml four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube. A solution of 1.2 g of solid content 50% by weight) and 100 g of distilled water was added dropwise over 30 minutes with a dropping lot while stirring at 300 rpm. In addition, 5 g of vinyl monomer of MMA / nBA / MAA = 49/50/1 (weight ratio) was added dropwise over 10 minutes, raised to 70 ° C. and 0.5 g of camphor persulfate was added and left for 60 minutes. After adding 1.0 g of anionic surfactant (25 weight% of solid content) after that, 95 g of vinyl monomers of MMA / nBA / MAA = 49/50/1 (weight ratio) are dripped over 4 hours. The temperature during the dropping is maintained at 70 ° C. and after completion of the dropwise addition is maintained at 70 ° C. for 1 hour to continue stirring. Cool and then operate to pH 8.5 with 25% ammonia water to obtain 400 g of aqueous dispersion (50 wt% solids, average particle diameter 60 nm).

Synthesis Example 6

  250 g of colloidal silica was added to a 1000 ml four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube, and 6.25 g of a cationic surfactant was added under stirring to add 1.2 g of a reactive cationic surfactant. A solution of 50 g of distilled water was added dropwise over 30 minutes with a dropping lot while stirring at 300 rpm. In addition, 5 g of vinyl monomer of MMA / nBA / MAA = 49/50/1 (weight ratio) was added dropwise over 10 minutes, raised to 70 ° C., 0.5 g of ammonium was added, and left to stand for 60 minutes. After adding 1.0 g of anionic surfactant (emulsion 20C, 25 weight% of solid content) after that, 95 g of vinyl monomers of MMA / nBA / MAA = 49/50/1 (weight ratio) are dripped over 4 hours. The temperature during the dropping is maintained at 70 ° C and stirring is continued for 1 hour after completion of dropping at 70 ° C. It was then cooled and operated to pH 8.5 with 25% ammonia water to obtain 400 g of an aqueous dispersion (50 wt% solids, 49 nm in average particle diameter).

<Synthesis example 7-12>

  Using the components shown in Table 1, an aqueous dispersion was obtained in the same manner as in the above synthesis example.

<Comparative Example 1>

  250 g of colloidal silica and 20 g of anionic surfactant (25 wt% solids) were added to a 1000 mL glass-necked four-necked flask equipped with a stirring device, a thermometer, a dropping lot, and a reflux cooling tube, and 135 g of distilled water was added. Adjust to 5 and stir. After raising the temperature to 60 ° C. under a nitrogen stream, 10 g of 3-methacrylateoxypropynetrimethoxyoxyral is added and stirred for 4 hours. Then, 0.5 g of ammonium persulfate and 0.2 g of sodium bisulfite are added, and 100 g of a vinyl monomer of MMA / nBA / MAA = 49/50/1 (weight ratio) is added dropwise over 4 hours. The reaction temperature during the dropping is maintained at 65 ° C., and the stirring is continued for one hour after the end of dropping. After cooling, the mixture was adjusted to pH 8.5 with 25% aqueous ammonia to obtain 500 g of an aqueous dispersion (50 wt% of solid content, 41 nm in average particle diameter).

<Comparative Example 2>

  300 g of colloidal silica was added to a 1000 ml four-necked flask equipped with a stirrer, thermometer, dropping lot, and reflux condenser, adjusted to pH8.5 with 2N-H2SO4, and then anionic surfactant (emulsion 20C, solid content). 25 wt%) 20g, add a solution of 100g of distilled water and increase the temperature to 70 ° C. Under nitrogen stream, 0.5 g of potassium perchlorate was added and 100 g of vinyl monomer of MMA / nBA / MAA = 49/50/1 (weight ratio) was added dropwise over 4 hours, after which the temperature was raised to 70 ° C. for one hour, followed by stirring. Continue. After cooling, the mixture was adjusted to pH 8.5 with 25% ammonia water to obtain 509 g of an aqueous dispersion (50 wt% of solid content, 49 nm in average particle diameter).

<Comparative Example 3>

  To a 1000 ml four-necked flask equipped with a stirrer, thermometer, dropping lot, and reflux cooling tube, 12 g of colloidal silica (25 wt% solids), 333 g of colloidal silica (30 wt% solids), and 65 g of distilled water were added. , And stir. After raising the temperature to 60 ° C. under a nitrogen stream, 0.5 g of ammonium persulfate and 0.2 g of sodium bisulfite were added and MMA / nBA / MAA / γ-methacrylateoxypropinetrimethoxyoxyral = 49 / 49.5 / 100 g of 1 / 0.5 (weight ratio) vinyl monomer is dripped over 3 hours. The reaction temperature during the dropping is maintained in the range of 60 to 70 ° C., and the stirring is continued at the same temperature for 2 hours after the completion of dropping. After cooling, the mixture was adjusted to pH 8.5 with 25% ammonia water to obtain 508 g of a composite fine particle dispersion (39 wt% solids, average particle diameter: 76 nm).

<Compound Particle, Polymer Particle and Colloidal Silica Particle Ratios> The aqueous dispersions of Synthesis Examples 1, 2, 3, 4, 5, 6 and Comparative Synthesis Example 3 are analyzed by transmission electron microscope. First, the aqueous dispersion, which is a sample, is diluted 10-fold with distilled water, and the dilution liquid is dried by placing a very small amount on a mesh Cu200A covered with a carbon film using a spatula. The dry film is observed with a transmission electron microscope TEM. Acceleration voltage 1000kV. The number ratio of single particle / colloidal silica particles is calculated for only one sample under the condition of the ratio of 20,000. In addition, the core-shell composite particle / polymer in the aqueous spray body obtained in the comparative synthesis example.

 The number ratio of single particles / colloidal silica particles is 12/25/63.

<Table 1>

Synthetic example Colloidal Silica Amount
(Particle diameter nm) Cation
Surfactants
(Parts by weight) Monomer composition
(Parts by weight)
Cationic
Radical species
Core-shell / polymer / silica
(Number ratio) One AT-50 100 parts by weight 20-30 nm NE-20
2.4 50/49/1
nBA / MMA / MAA
100 Cationic initiator
98/0/2
2 ST-50 100 parts by weight 20-30 nm
840S
2.1
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
98/0/2
3 ST-40 100 parts by weight 10-15 nm
NE-20
3
50/49/1
nBA / MMA / MAA
100 Responsive
Cation
Surfactants - 4 AT-50 100 parts by weight 20-30 nm
NE-20
5
50/49/1
nBA / MMA / MAA
100 Cationic initiator
63/35/2
5 ST-50 100 parts by weight 20-30 nm
840S
2.1
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
72/0/28
6 ST-50 100 parts by weight 10-15 nm
NE-20
5
50/49/1
nBA / MMA / MAA
100 Responsive
Cation
Surfactants 57/21/22
7 AT-50 150 parts by weight 20-30 nm
NE-20
3.5
50/49/1
nBA / MMA / MAA
100 Cationic initiator
- 8 AT-50 300 parts by weight 20-30 nm
NE-20
6
50/49/1
nBA / MMA / MAA
100 Cationic initiator
- 9 AT-50 500 parts by weight 20-30 nm
NE-20
8
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
- 10 Snowtex YL 300 parts by weight
20-30 nm NE-20
One
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
- 11 Snowtex YL 500 parts by weight
20-30 nm NE-20
1.5
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
- 12 ST-50 100 parts by weight
20-30 nm NE-20
2.1
50/49/1
nBA / MMA / MAA
100 Cation
Monomer
52/8/40

Rather, the dispersions of Synthesis Examples 1 and 2 are aqueous dispersions composed of core-shell-type composite particles with little polymer alone particles and little colloidal silica particles. The aqueous spray of Synthesis Example 4 was composed of 35% by weight of polymer single particles and about 65% by weight of core-shell structured composite particles. The aqueous dispersion of Synthesis example 5 is composed of about 30% by weight silica particles and 65% core-shell structured composite particles. The aqueous dispersion of Synthesis Example 6 is composed of a three-component system of core-shell structured composite particles / polymer single particles / silica particles. The aqueous dispersion of Comparative Synthesis Example 1 has some recognized core-shell structured composite particles, but most are polymer single particles and silica particles.

The aqueous dispersions of Synthesis Examples 2, 3, 6 and Comparative Synthesis Example 1 were stored at room temperature for 3 months, and stored at 50 ° C for 10 days to examine accelerated storage stability. The results are shown in Table 2.

<Table 2>

Room temperature 3 months 50 ° C x 10 days Synthesis Example 2 clear clear Synthesis Example 3 clear clear Synthesis Example 6 clear clear Comparative Synthesis Example 1 Some thickening Pronounced thickening

The aqueous dispersions of Synthesis Examples 2, 3 and 6 show good storage stability without change in appearance and thickening even in storage stability at room temperature and accelerated testing at 50 ° C. On the other hand, as a comparative synthesis example, the tendency of cognitive thickening was judged by a silane compound exceptionally, and the thickening was judged clearly in the accelerated test especially at 50 degreeC.

Paint composition

 Example 1

  To a 500 ml steel beaker, 10.8 g of distilled water, 5.0 g of distillate (20% by weight), dispersant, 4.0 g of wetting agent, and 0.8 g of surface conditioner were added. Stir at a speed of 3000 rpm over. Thereafter, 200 g of the aqueous dispersion (emulsion) of Synthesis Example 1 was added at a rotational speed of 1000 rpm, respectively, and 60 g of distilled water were added, followed by stirring for 5 minutes. Next, 12 g of the film forming agent is added, stirring is continued for another 5 minutes, and a white paint is obtained.

  Comparative Example 1

 Over 200 g of the aqueous dispersion of Synthesis Example 1, 200 g of an emulsion (50% by weight) was used to obtain a white paint. That is, 10.8 g of distilled water, 5.0 g (20 wt%) of thickener, 4.0 g of dispersant, 1.0 g of wetting agent, and 0.8 g of surface conditioner were added to a 500 ml steel beaker, and 80 g of titanium oxide was added to the separator while stirring at 1000 rpm. After setting the rotation speed to 3000 rpm, the stirring was continued for 15 minutes. Thereafter, the number of revolutions was set to 1000 rpm, followed by 50 g of emulsion (50 wt%) and 150 g of colloidal silica. In addition, 60 g of water and 12 g of film forming agent are added to obtain a stirred 10 decomposition white paint.

  Comparative Example 2

 Over 200 g of the aqueous dispersion of Synthesis Example 1, an emulsion (50% by weight, water paint), 50 g, and 150 g of colloidal silica were used to obtain a white paint. That is, 10.8 g of distilled water, 5.0 g (20 wt%) of thickener, 4.0 g of dispersant, 1.0 g of wetting agent, and 0.8 g of surface conditioner were added to a 500 ml steel beaker, and 80 g of titanium oxide was added to the separator while stirring at 1000 rpm. After setting the rotation speed to 3000 rpm, the stirring was continued for 15 minutes. Thereafter, the rotation speed was set at 1000 rpm, and then 50 g of an emulsion (50 wt%, water paint) and 150 g of colloidal silica were added. In addition, 60 g of water and 12 g of film forming agent are added to obtain a stirred 10 decomposition white paint.

  Table 3 shows the paint compositions of other examples and comparative examples simultaneously with the compositions of the paints of the examples and comparative examples.

  EXAMPLES AND COMPARATIVE EXAMPLES A sample is produced as follows for paint. 15 times of water is added to 100 times the paint obtained in the Example and the comparative example, and after sample adjustment, it coats with a spraying machine so that the coating amount may be 200 g / m <2> on a 70 * 150m slate board, and it is made to stand at room temperature for 7 days. The L-shaped slate panel consists of a plate perpendicular to the ground (20 cm wide x 30 cm high) and a hardness plate (20 cm wide x 70 cm wide) that prevents tilting at an angle of 120 ° from the top of the plate. And the hardness plate end is supportable.

  And the following results are obtained when evaluating coating film formation resistance, resistance, alkali resistance, rain resistance, freeze resistance, accelerated weather resistance, outdoor exposure test, and stain resistance.

[Test method and evaluation method]

(1) storage stability

100 g of paint is placed in a 200 ml container, stored in a 50 ° C hot air drying furnace for 10 days, and the state of the paint is observed and observed. Evaluation is based on the following criteria.

(2) coating film formability

It draws on a glass plate with a doctor blade (4 mils), it is made to dry at room temperature, a coating film is observed under a microscope, and the following references | standards evaluate.

(3) adhesion

A 100/100 case is written on the checkerboard and 0/100 a case where the checkerboard is recorded completely is displayed without a cello tape distance test having a cross cut of 2 mm in width.

(4) water resistance

It is immersed in water for 20 days, and the state of the water film is observed visually and is evaluated by the following reference | standard.

(5) alkali resistance

It is immersed in 30% NaOH aqueous solution for 7 days, the state of a coating film is visually observed, and the following reference | standard evaluates.

(6) frost resistance

A test plate immersed in tap water was provided with a 50-site freezing test for 16 hours at -20 ° C and 8 hours at 20 ° C for one cycle.

(7) Actual exposure test

The appearance (glossy, cleavage, discoloration) of the coating film after 18 months is observed and evaluated based on the following criteria.

(8) pollutant

It is coated on the stainless steel plate shown in the figure and visually observed by discoloration of the inclined part and the vertical part after 6 months, and evaluated according to the following criteria.

(Criteria)

(Double-circle): There is no change of a coating film. Clearly good.

(Circle): Most of a coating film does not change. Good.

△: level of change of coating film slightly, practically no problem

▲: The coating film changes a little and practically causes a problem.

X: There are many changes of a coating film, and there is a flaw in practicality.

  As shown in Table 3, in Examples 1 to 6 coating films, compared with Comparative Example 1, pollution resistance, outdoor exposure test (weather resistance), water resistance, and the like were improved by 1 or 2 positions. In addition, in Example 2, the film formability, the adhesive agent, the resistance, etc. were improved and the balance | balance of the coating film property was shown in the contrast with Example and Comparative Example 2. Moreover, the glossiness of a coating film can be adjusted in a wide range by using the emulsion containing colloidal silica. Alternatively, in Examples 2 and 3 using emulsions having high content of colloidal silica (containing examples 8 and 9), heat resistance can be imparted without adding a heat-retardant.

Claims (4)

As colloidal silica particles, an average particle diameter of 5 nm to 1 μm, preferably a method of using an anhydrous silicic acid particle colloid (colloid) of about 10 to 100 μm of an aqueous acid. The amount of cationic polymerization active species is 0.1 to 20 parts by weight based on 100 parts by weight of the vinyl polymer, and the amount of silica polymerization active species to colloidal silica particles is cationic polymerization based on 100 parts by weight of colloidal silica particles in terms of solid content. The production method to 0.1 to 20 parts by weight of active species. The said vinyl monomer makes the glass transition temperature into -30-80 degreeC. The ratio between the vinyl polymer and the colloidal silica particles can be selected according to film forming properties, and the like, for example, 3 to 500 parts by weight of the colloidal silica particles, preferably 10 to 300 parts by weight, and more preferably 100 parts by weight of the vinyl polymer. The thing about 20-200 weight part (for example, 30-200 weight part).