JP4979494B2 - Re-emulsifiable resin powder composition for hydraulic material, aqueous emulsion for hydraulic material, and building finish coating material using them - Google Patents

Description

The present invention relates to a re-emulsifiable resin powder composition for a hydraulic material obtained by drying an aqueous synthetic resin emulsion, and more particularly, particularly for drying-resistant initial rainfall of a coating film, particularly for an architectural finish coating material and powder coating for exterior use. sex (water resistance), premature drying properties, excellent drying early expression of the coating film hardness, in addition, trowel workability is good, and the hydraulic material for obtaining a high hydraulic material for aqueous emulsion of anti-skinning effect The present invention relates to a re-emulsifiable resin powder composition. In addition, it can be used for various applications such as an admixture for hydraulic materials such as cement and gypsum, an adhesive for wood or wood, and paper.

  The re-emulsifiable resin powder is produced by drying the aqueous synthetic resin emulsion by a method such as spray drying, and since it is a powder, it can be handled more easily than the aqueous synthetic resin emulsion mainly used in cans and drum packaging. It is easy, and since it is usually a paper bag package, it is advantageous in terms of product storage and transportation costs. Furthermore, the re-emulsifiable resin powder has less volatile components such as residual monomers compared to general aqueous synthetic resin emulsions and does not rot because it contains no water, so it does not require mold and preservatives. It has been recognized as a gentle product.

  In addition, since this re-emulsifiable resin powder can be re-emulsified in water simply by adding it to water and stirring at the time of use, it has so far been mainly used as a mixing agent for cement products such as concrete structures and mortar and gypsum putty. Furthermore, it is widely used for architectural finishing coating materials, powder paints, adhesives and the like. In particular, the re-emulsifiable resin powder can be mixed in advance with an inorganic hydraulic composition such as a building finish coating material / powder coating composition and mortar / gypsum putty. Cement products, gypsum products, architectural finishes and powder paints can be formed.

  However, until now, re-emulsifiable resin powders blended in building finish coating materials / powder coating compositions and inorganic hydraulic compositions such as mortar and gypsum have water-soluble properties such as polyvinyl alcohol to emphasize re-emulsification. High hydrophilicity such as vinyl acetate polymer, ethylene / vinyl acetate polymer, vinyl acetate / versaic acid vinyl ester polymer, vinyl acetate / acrylic polymer with resin as protective colloid (dispersion stabilizer) Since there are many re-emulsifiable resin powders of the polymer composed of the composition and there is almost no water resistance of the film, especially the dry initial rain resistance (water resistance etc.) of the coating film, the initial expression of drying of the coating film hardness, etc. are required. It was insufficient in physical properties as a re-emulsifiable resin powder for exterior building finishes and powder coatings. The necessity of the initial rainfall resistance (water resistance, etc.) of the coating film is affected by, for example, when it is applied in summer, even if the weather suddenly changes and it rains, the coating surface that has not been applied is affected. The coated surface is required to be finished to such an extent that it will not be affected. Further, the initial dryness of the coating film hardness is required to be finished to the extent that the coating surface is not affected even if the coating film surface is touched in the case of entering the next work step after coating. Therefore, there has been a demand for a re-emulsifiable resin powder for architectural finishing coating materials and powder coatings that has good dry initial rainfall resistance (water resistance, etc.) and good dry initial expression of coating film hardness. In addition, in winter work, drying of the coating film is slow and often affects the next process, and a re-emulsifiable resin powder for building finish coating materials and powder coatings with good early drying properties is desired. It was.

  However, on the other hand, architectural finish coating materials for exteriors are often given a design effect by applying a three-dimensional pattern to the coating surface with a trowel after coating. Even if the film thickness is about 1.5 to 2 mm, drying of the coating film proceeds, and there is a problem that it becomes impossible to pattern the coating surface with a trowel or the like in about 30 minutes of coating. As a patterning method, it is common from the point of work efficiency to pattern a certain area with a trowel after application, but in order to prevent the problem, patterning is performed for each small area. There has also been proposed a method for providing designability in line. However, this method is inferior in work efficiency, and in some cases, the balance of patterns is expected to be lost. Therefore, from the market, it retains the initial drying resistance (water resistance) and early drying resistance of the coating film, and the initial expression of drying of the coating film hardness. Re-emulsification, especially for exterior finishing coating materials for exterior building materials, which has good iron workability that enables patterning on the painted surface with high resistance, etc. and has a high anti-skinning effect. Resin powder has been desired.

  In general, many of the known re-emulsifiable resin powders that can be re-emulsified in water have a low degree of polymerization mainly due to the need to re-emulsify, and partially saponified polyvinyl alcohol is a protective colloid (dispersed) It is obtained by emulsion polymerization using a vinyl ester monomer mainly composed of vinyl acetate as a main component (see, for example, Patent Document 1 and Patent Document 2).

  Moreover, as a re-emulsifiable resin powder for the purpose of water resistance, as described in Patent Document 2, an emulsion powder composition containing a re-emulsifiable synthetic resin emulsion powder and an oxide or hydroxide of calcium or magnesium Or a polymer particle composed of at least one of an ethylenically unsaturated monomer or a diene monomer, has an acetoacetic acid group and / or a mercapto group, and has a block character of 0.3 to Re-emulsifiable synthetic resin powder having a polyvinyl alcohol resin of 0.6 adsorbed (for example, see Patent Document 3), and further, the block character of acetoacetate group-containing polyvinyl alcohol further separated into a specific particle size Is the aqueous emulsion of 1.0 to 3.0 obtained by dividing the maximum value of the average degree of acetoacetate ester by the minimum value? Re-emulsifiable synthetic resin powder comprising (e.g., see Patent Document 4) have been proposed.

  However, the disclosed technique of Patent Document 1 does not aim at water resistance of the film, and is a hydrophobic monomer mainly selected from acrylic, styrene, vinyl, etc. in order to increase the water resistance of the film. Even if an attempt was made to produce an aqueous synthetic resin emulsion having a normal nonvolatile content (40 to 50%) using, the polymerization stability was poor.

  In addition, in each of the disclosed technologies of Patent Documents 2 to 4, although the water resistance of the film is improved, the dry rain resistance (water resistance, etc.), coating, and the like are particularly useful for exterior building finish coating materials and powder coatings. There has been a demand for further improvement in physical properties of the initial dryness of the film hardness, in addition to improvement in the washing resistance and durability of the coating film, and it has not been satisfactory, and further improvement has been required.

  Furthermore, depending on the case, especially in exterior finish coating materials for exteriors, in order to develop dry initial expression of coating film hardness and dry initial rainfall resistance (water resistance, etc.), there may be a device to increase the non-volatile content. The time for enabling patterning with a trowel after coating will be shortened. In order to lengthen the time for enabling patterning, the use of a water retention agent such as hydroxymethylcellulose can be considered. However, in this case, the initial drying property of coating film hardness, the initial rainfall resistance (water resistance) Etc.) is significantly reduced.

  Therefore, the aqueous emulsion has a good balance between the initial rainfall resistance (water resistance) and early drying properties of the coating film, and the initial dryness of the coating film hardness and the patterning property on the coating surface by the iron after coating, etc. Actually, there is no product on the market related to the re-emulsifiable resin powder to obtain the product.

Japanese Patent Laid-Open No. 5-140325 Japanese Patent Laid-Open No. 5-179008 Japanese Patent Laid-Open No. 2002-60406 JP-A-2005-272481

Therefore, in the present invention, under such a background, as an exterior architectural finish coating material / powder coating, it has dry initial rain resistance (water resistance, etc.) and coating initial hardness drying properties. In addition, it forms the wash resistance and durability of the paint film, and in particular for exterior finish coating materials for exteriors, it prevents skinning even in the summer when the paint film surface dries quickly, so that it can be applied to the coated surface with a trowel etc. after coating and to provide a pattern with the possibility to be for a hydraulic material re-emulsifiable resin powder composition for obtaining a trowel good workability for a hydraulic material aqueous emulsion can.

  However, as a result of intensive studies in view of such circumstances, the present inventor is a re-emulsifiable resin powder made of an aqueous synthetic resin emulsion using a specific polyvinyl alcohol-based resin as a protective colloid, and further contains a crosslinking agent and silica. In particular, the re-emulsifiable resin powder composition is suitable for use in exterior building finish coating materials and powder coatings. Improves the washing resistance and durability of the film, especially in the case of exterior building finish coating materials, preventing skinning even in the summer when the coating film surface dries quickly, and patterning the coated surface with a trowel etc. after coating The present invention has been completed by finding that it can be made possible.

That is, the gist of the present invention is that a synthetic resin obtained by polymerizing an ethylenically unsaturated monomer component containing 30% by weight or more of a hydrophobic monomer and containing a styrenic monomer is present in the side chain. A re-emulsifiable resin powder (I) comprising an aqueous synthetic resin emulsion (A) dispersed and stabilized with a polyvinyl alcohol resin (a 2 ) having a 2-diol bond , silica (II), and a crosslinking agent (III And a re-emulsifiable resin powder composition for hydraulic materials .

  The ethylenically unsaturated monomer component is selected from the group consisting of allyl group-containing monomers, glycidyl group-containing monomers, hydrolyzable silyl group-containing monomers, acetoacetyl group-containing monomers, vinyl group-containing monomers, and carbonyl group-containing monomers. It is preferable to contain the above functional monomer.

  The re-emulsifiable resin powder (I) is preferably composed of an emulsion containing the aqueous synthetic resin emulsion (A) and the re-emulsification improver (B).

  The re-emulsification improver (B) is preferably a polyvinyl alcohol resin (b) having an average saponification degree of 85 mol% or more and an average polymerization degree of 50 to 3000.

  The polyvinyl alcohol resin (b) is at least one selected from the group consisting of an acetoacetyl group-modified polyvinyl alcohol resin, a carbonyl group modified polyvinyl alcohol resin, and a polyvinyl alcohol resin having a 1,2-diol bond in the side chain. Preferably it is a seed.

Silica (II) is preferably silica having a BET specific surface area of 50 to 400 m ² / g.

  The crosslinking agent (III) is preferably at least one selected from the group consisting of polyvalent metal salts, tertiary or quaternary cationic resins and hydrazide compounds.

Further, the present invention relates to a hydraulic material for aqueous emulsion characterized by being obtained by re-emulsifiable the hydraulic material for re-emulsifiable resin powder composition.

The present invention also relates to the hydraulic material for re-emulsifiable resin powder composition or comprising an aqueous emulsion for the hydraulic material building finish materials.

Moreover, building, characterized by containing the hydraulic material for re-emulsifiable resins powder composition or the hydraulic material for aqueous emulsion architectural finish materials, powder coating formulation consisting of a hydraulic material It relates to finish coating materials.

The re-emulsifiable synthetic resin powder composition for hydraulic materials of the present invention comprises a re-emulsifiable resin powder comprising an aqueous synthetic resin emulsion having a specific polyvinyl alcohol-based resin as a protective colloid, a crosslinking agent and silica, thereby It is redispersible in an aqueous emulsion for hydraulic materials, in particular, for the exterior building finish materials, powder coating materials, anti-dry initial rainfall resistance (water resistance, etc.), dried early expression of the coating film hardness, winter early In addition to dryness, especially in the case of exterior finishing coating materials for exteriors, it can prevent skinning even in the summer when the paint film surface is dry quickly, and can be used to pattern the coated surface with a trowel after coating. Has an excellent effect. In addition, it is also useful for various applications such as admixtures for hydraulic materials such as cement and gypsum, wood or wood, and adhesives for paper.

  The present invention is described in detail below.

The re-emulsifiable synthetic resin powder composition for hydraulic materials according to the present invention is obtained by polymerizing an ethylenically unsaturated monomer component containing a hydrophobic monomer at 30% by weight or more based on the total monomer components and containing a styrene monomer. The resulting synthetic resin is a re-emulsifiable resin powder (I) composed of an aqueous synthetic resin emulsion (A) dispersed and stabilized with a polyvinyl alcohol resin (a 2 ) having a 1,2-diol bond in the side chain , silica ( II) and a re-emulsifiable resin powder composition for hydraulic materials , characterized by containing a crosslinking agent (III). In the following, “re-emulsifiable synthetic resin powder composition for hydraulic material” may be referred to as “re-emulsifiable synthetic resin powder composition”, and “aqueous emulsion for hydraulic material” is sometimes referred to as “aqueous emulsion”. May be written.

  Here, the re-emulsifiable resin powder refers to a powder capable of generating an emulsion when re-emulsified in an aqueous medium such as water.

  In the present invention, polyvinyl alcohol (hereinafter referred to as PVA) resin (a) is used as a protective colloid (dispersion stabilizer) for emulsion polymerization.

  The average saponification degree of the PVA-based resin (a) is preferably 85 to 99.5 mol%, and more preferably 95 to 99 mol%. If the average saponification degree is too small, the polymerization may not proceed stably, and even when the polymerization is completed, the storage stability of the aqueous emulsion tends to be poor. Moreover, when too large, there exists a tendency for it to become difficult to re-disperse.

  In the present specification, the average saponification degree can be determined according to JIS K 6726.

  Moreover, as average polymerization degree of PVA-type resin (a), it is preferable that it is 50-2000, It is more preferable that it is 200-1000, It is further more preferable that it is 200-500. If the average degree of polymerization is too small, the protective colloid ability at the time of emulsion polymerization will be insufficient and the polymerization will not proceed stably, and if it is too large, the reaction system will become unstable and the redispersibility will be lowered. Tend to.

  In the present specification, the average degree of polymerization can be determined according to JIS K 6726.

  In the present invention, the PVA resin (a) is a PVA resin (a1) containing active hydrogen, the reactivity of the copolymerizable monomer is good, the polymerization stability is excellent, and the nonvolatile content is high. This is preferable because an emulsion can be obtained. When an emulsion having a high non-volatile content is obtained, the drying property of the emulsion is improved, and in particular, the heat source energy can be saved during spray drying, which is preferable.

  Examples of the PVA resin (a1) containing such active hydrogen include acetoacetyl group-modified PVA resin, mercapto group modified PVA resin, diacetone acrylamide modified PVA resin, and the like. The acetoacetyl group-modified PVA resin is used for reasons such as improving stability, improving re-emulsification of the resin powder, and improving the water resistance of the coating because the graft ratio to the synthetic resin is increased. Most preferred.

  The acetoacetylation degree of the acetoacetyl group-modified PVA resin is preferably 0.01 to 10 mol%, more preferably 0.01 to 6 mol%, and 0.03 to 3 mol%. More preferably, it is particularly preferably 0.03 to 2 mol%, and most preferably 0.03 to 1 mol%. If the degree of acetoacetylation is too small, the polymerization stability, the water resistance of the film and the mechanical stability tend to decrease, and the boiling resistance and miscibility with fillers tend to decrease. If it is too large, the polymerization stability during emulsion polymerization tends to be poor.

  Furthermore, it is preferable that the acetoacetyl groups present on the PVA molecule are relatively randomly arranged in the molecule rather than those arranged in a block form in a fixed region in the molecule.

  The average saponification degree of the acetoacetyl group-modified PVA resin is preferably 90 mol% or more, and more preferably 97 to 99.8 mol%. If it is too small, it becomes difficult for the polymerization to proceed stably, and even if the polymerization is completed, the storage stability of the aqueous synthetic resin emulsion tends to be poor. On the other hand, if it is too large, the polymerization stability is deteriorated and gelation may occur during the polymerization, and even if the polymerization is completed, it tends to be difficult to re-emulsify.

  The average degree of polymerization of the acetoacetyl group-modified PVA resin is preferably 50 to 2000, and more preferably 200 to 600. If it is too small, the protective colloid ability at the time of emulsion polymerization will be insufficient and the polymerization will not proceed stably, and if it is too large, the reaction system will become unstable due to polymerization and the re-emulsification will tend to decrease. There is.

In the present invention, among the PVA-based resins (a), a 1,2-diol bond is added to the side chain of the PVA-based resin, particularly from the viewpoint of increase in the non-volatile content of the emulsion and ease of polymerization. PVA-based resin having (a2) is used more rather preferable.

  Examples of the PVA resin (a2) having a 1,2-diol bond in such a side chain are usually PVA resins containing a 1,2-diol structural unit represented by the following general formula (1).

〔ここで、上記式（１）において、Ｒ¹、Ｒ²、Ｒ³はそれぞれ独立して水素またはアルキル基である。〕

[In the above formula (1), R ¹ , R ² and R ³ are each independently hydrogen or an alkyl group. ]

  Such a PVA-based resin (a2) is, for example, (a) a method of saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, and (b) a method of vinyl acetate and vinyl ethylene carbonate. A method of saponifying and decarboxylating a copolymer, (c) a method of saponifying and deketalizing a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane, ) A method of saponifying a copolymer of vinyl acetate and glyceryl monoallyl ether, and the like.

  The average degree of saponification of the PVA resin (a2) having a 1,2-diol bond in the side chain is preferably 85 to 100 mol%, more preferably 90 to 99.8 mol%. If the average saponification degree is too small, the stability of the emulsion during polymerization tends to be lowered, and it becomes difficult to obtain the desired aqueous emulsion.

  Moreover, it is preferable that the 1, 2- diol bond amount of the side chain of this PVA-type resin (a2) is 1-15 mol%, More preferably, it is 1-12 mol%, More preferably, it is 2-10 mol%. More particularly preferably, it is 2 to 8 mol%. If the content of the 1,2 diol component is too small, the mechanical stability of the emulsion and the water resistance of the film tend to decrease. If the content is too large, the stability at the time of polymerization decreases, and the non-volatile content is high and stable. Emulsions tend to be difficult to catch.

  The average degree of polymerization of the PVA resin (a2) having a 1,2-diol bond in the side chain is preferably 50 to 2500, more preferably 100 to 1700, still more preferably 100 to 1000, and particularly preferably 200 to 500. is there. If the average degree of polymerization is too small, it tends to be difficult to industrially produce a PVA resin, and if it is too large, the viscosity of the emulsion tends to be too high, or the polymerization stability of the emulsion tends to be low.

  In the present invention, the amount of the PVA resin (a) used as the protective colloid (dispersion stabilizer) is preferably 3 to 20% by weight based on the total copolymerization monomer component, and 4 to 10% by weight. % Is more preferable. If the amount is too small, the amount of the protective colloid at the time of emulsion polymerization will be insufficient, and the polymerization stability tends to be poor. Thus, there is a tendency that the water resistance in the application is lowered.

  In the present invention, as the PVA-based resin (a), the PVA-based resin can be used alone, or two or more kinds can be used as a mixture. PVA or the like can be used in combination as long as the object of the present invention is not impaired.

  In the present invention, the PVA resin (a) is usually used as an aqueous solution using an aqueous medium in the course of emulsion polymerization. Here, the aqueous medium refers to water or an alcoholic solvent mainly composed of water, preferably water.

  The amount of PVA resin (a) in this aqueous solution (in terms of non-volatile content) is not particularly limited, but is preferably 5 to 30% by weight from the viewpoint of ease of handling.

  Furthermore, in the present invention, at least a part of the PVA resin (a) is grafted to the aqueous synthetic resin described below, so that the obtained aqueous synthetic resin emulsion (A) itself before drying can be stored stably. This is preferable from the standpoint that variations in evaluation in the measurement of adhesiveness and adhesiveness are reduced.

  The proportion of the synthetic resin grafted with the PVA resin (a) is preferably 50% by weight or more, more preferably 60 to 95% by weight, and 65 to 85% by weight based on the whole synthetic resin. Further preferred. If the amount is too small, the protective colloid action at the time of emulsion polymerization is lowered, the polymerization stability is lowered, and in addition, the miscibility with fillers tends to be lowered.

  As a method of adjusting the ratio of the grafted synthetic resin to 50% by weight or more, the emulsion polymerization temperature is made slightly higher than before, or a very small amount of reducing agent (for example, acidic sulfurous acid is added to a persulfate used as a polymerization catalyst. And soda).

  The aqueous synthetic resin emulsion (A) in the present invention comprises a synthetic resin obtained by emulsion polymerization of an ethylenically unsaturated monomer component containing 30% by weight or more of a hydrophobic monomer with respect to the total monomer component, and the PVA resin ( The emulsion is dispersion-stabilized in a).

  In the present invention, by using a hydrophobic monomer, desired initial dry rain resistance (water resistance, etc.), initial dryness of coating hardness, early drying in winter, toughness of coating, and washing resistance Adhesiveness to the substrate can be obtained.

  Here, the initial dry rain resistance (water resistance, etc.) means that, for example, when applied in summer, even if the weather suddenly changes and it rains, the coated surface with no coating is affected. It indicates that the coating surface is finished to the extent that it is not, and the initial dryness of the coating film hardness means that the coating film surface is touched when entering the next work process after coating. This indicates that the coating surface is finished to the extent that it is not affected.

  The glass transition temperature of the synthetic resin is not particularly limited, but from the standpoint of physical properties such as adhesion to the ground such as mortar and slate plate, toughness of the coating film, and washing resistance for architectural finishing coating materials and powder coatings- It is preferably 35 to 20 ° C, more preferably -25 to 10 ° C, and further preferably -20 to 0 ° C. If the glass transition temperature is too low, the adhesion of the coating film to the base, the toughness of the coating film, and the washing resistance tend to decrease.If the glass transition temperature is too high, a plasticizer such as dibutyl phthalate is added to form an emulsion film. It is necessary to lower the temperature, and as a result, the adhesive strength, toughness, and washing resistance of the coating film to the ground tend to be lowered.

  The hydrophobic monomer to be used in the present invention is a monomer that is substantially insoluble in water, and is usually a monomer having a solubility in water at 20 ° C. of 0.3% by weight or less, more preferably 0.2%. It is a monomer that is not more than% by weight. These monomers are usually selected from acrylic monomers, styrene monomers, and vinyl monomers.

  Examples of acrylic monomers include n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl methacrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, and octyl. Alkyl (meth) acrylates having an alkyl group such as (meth) acrylate and stearyl (meth) acrylate having 4 or more carbon atoms, preferably 6 to 18; aromatic (meth) acrylates such as phenoxy acrylate; trifluoroethyl methacrylate, etc. These can be used alone or in combination of two or more. Among these, 2-ethylhexyl acrylate and n-butyl acrylate are preferable.

Examples of the solubility of the monomer in water at 20 ° C. are as follows.
n-butyl acrylate: 0.2% by weight
n-butyl methacrylate: 0.04% by weight
i-Butyl methacrylate: 0.04% by weight
t-Butyl methacrylate: 0.05% by weight
2-ethylhexyl acrylate: 0.01% by weight
2-ethylhexyl methacrylate: 0.01 wt% or less Cyclohexyl methacrylate: 0.01 wt% or less Lauryl methacrylate: 0.01 wt% or less Stearyl methacrylate: 0.01 wt% or less Trifluoroethyl methacrylate: 0.04 wt%

  Here, (meth) acrylate means acrylate or methacrylate.

  Examples of the styrenic monomer include styrene and α-methylstyrene, and these can be used alone or in combination of two or more. Among these, styrene is preferable.

  Examples of the vinyl monomer include vinyl laurate, vinyl stearate, vinyl versatate (solubility in water at 20 ° C .: 0.1% by weight or less), and these are used alone or in combination of two or more. can do.

  Further, two or more hydrophobic monomers can be used in combination depending on the physical properties of the re-emulsifiable resin powder.

  In the present invention, since the purpose is to produce an emulsion having excellent water resistance when a coating film is formed, the content of the hydrophobic monomer needs to be relatively high. Is 30% by weight or more, preferably 40 to 100% by weight, based on all copolymerizable monomer components. When the amount of the hydrophobic monomer used is reduced, the desired initial dry rain resistance (water resistance, etc.), initial dryness of the coating film hardness, early drying in winter, toughness of the coating film, cleaning resistance, groundwork Adhesiveness to is insufficient.

  The ethylenically unsaturated monomer component used in the present invention can contain a copolymerizable monomer copolymerizable with the hydrophobic monomer.

  The copolymerizable monomer is not particularly limited, but a (meth) acrylic monomer having an alkyl group with 3 or less carbon atoms such as methyl (meth) acrylate and ethyl (meth) acrylate; vinyl such as vinyl acetate and vinyl propionate Olefin monomers such as ethylene; halogenated olefin monomers such as vinyl chloride; acrylamides such as (meth) acrylamide, N, N-dimethylacrylamide, t-butylacrylamide, 2-acrylamide-2-methylpropanesulfonic acid Monomers, nitrile monomers such as (meth) acrylonitrile; vinyl ether monomers such as methyl vinyl ether, ethylenically unsaturated carboxylic acids such as (meth) acrylic acid and (anhydrous) itaconic acid, and ester monomers thereof It can be mentioned. Among these, a (meth) acrylic monomer having an alkyl group with 3 or less carbon atoms is preferable.

  Also, in the present invention, particularly when used for emulsion polymerization, from the point that the toughness of the coating film, the washing resistance, and the adhesion to the substrate can be obtained when used as an exterior architectural finish coating material or powder coating. It is preferred to copolymerize functional monomers.

  The functional monomer may be one or more selected from the group consisting of allyl group-containing monomers, glycidyl group-containing monomers, hydrolyzable silyl group-containing monomers, acetoacetyl group-containing monomers, vinyl group-containing monomers, and carbonyl group-containing monomers. Preferably there is.

  As the allyl group-containing monomer, for example, a monomer having two or more allyl groups such as triallyloxyethylene, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, diallyl phthalate, allyl glycidyl ether, And allyl acetate. Among these, allyl glycidyl ether is preferable from the viewpoint of adhesion to the base.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, and the like. Among these, glycidyl (meth) acrylate is preferable from the viewpoint of improving the water resistance and toughness of the coating film.

  Examples of the hydrolyzable silyl group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyl. Examples include methyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane. Among these, vinyltrimethoxysilane is preferable from the viewpoint of adhesion to inorganic materials.

  Examples of the acetoacetyl group-containing monomer include acetoacetate vinyl ester, acetoacetate allyl ester, diacetoacetate allyl ester, acetoacetoxyethyl (meth) acrylate, acetoacetoxyethyl crotonate, acetoacetoxypropyl (meth) acrylate, acetoacetoxypropyl Examples thereof include clotnerate and 2-cyanoacetoacetoxyethyl (meth) acrylate. Among these, acetoacetoxyethyl (meth) acrylate is preferable from the viewpoint of improving the water resistance of building finish coating materials and powder paints and adhering to the foundation.

  The vinyl group-containing monomer is preferably a monomer having two or more vinyl groups in the molecular structure. For example, divinylbenzene, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri ( Examples include meth) acrylate and allyl (meth) acrylate.

  Examples of the carbonyl group-containing monomer include diacetone acrylamide. Diacetone acrylamide is preferable from the viewpoint of improvement of water resistance, toughness, washing resistance and the like of building finish coating materials and powder coating materials, and adhesion to the substrate.

  These functional monomers can be used alone or in combination of two or more.

  According to a preferred embodiment of the present invention, the functional monomer is a hydrolyzable silyl group from the viewpoint of the toughness of the coating film, the washing resistance, and the adhesion to the substrate for exterior finish coating materials and powder coatings for exterior use. A monomer selected from the group consisting of a containing monomer, an acetoacetyl group-containing monomer and a carbonyl group-containing monomer is preferred, and a carbonyl group-containing monomer is more preferred.

  It is preferable that the usage-amount of a functional monomer is 0.05-10 weight% with respect to all the monomer components, It is more preferable that it is 0.5-7 weight%, It is 1-5 weight% Further preferred. If the amount is too small, there is a tendency that the toughness of the coating film, the washing resistance and the adhesion to the base are insufficiently improved, and if the amount is too large, poor polymerization or re-emulsification tends to be reduced.

  In the present invention, in addition to the copolymerizable monomer component such as the above-described hydrophobic monomer, other components can be further used as necessary. Such other components are not particularly limited as long as the properties as the re-emulsifiable resin powder are not lowered, and can be appropriately selected according to the purpose. Examples of other components include a polymerization initiator, a polymerization regulator, an auxiliary emulsifier, a plasticizer, and a film forming aid.

  Any polymerization initiator can be used without particular limitation as long as it can be used for ordinary emulsion polymerization. For example, inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; organic peroxides, azo initiators Agents, peroxides such as hydrogen peroxide and butyl peroxide; and redox polymerization initiators combining these with reducing agents such as acidic sodium sulfite and L-ascorbic acid. These are used in combination of two or more. May be. Among these, it is easy to carry out emulsion polymerization without adversely affecting the effects of the crosslinking agent that affects the initial drying resistance (water resistance, etc.), the initial development of coating film hardness, and the early drying characteristics of winter. Inorganic oxides, particularly ammonium persulfate and potassium persulfate are preferred.

  There is no restriction | limiting in particular as a polymerization regulator, It can select suitably from well-known things. Examples of such a polymerization regulator include a chain transfer agent and a buffer.

  Here, examples of the chain transfer agent include alcohols such as methanol, ethanol, propanol and butanol; aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, furfural and benzaldehyde; and dodecyl mercaptan, lauryl mercaptan, and normal mercaptan. And mercaptans such as thioglycolic acid, octyl thioglycolate, and thioglycerol. Two or more of these may be used in combination.

  Although the polymerization can be stably performed by using a chain transfer agent, the degree of polymerization of the synthetic resin is reduced, and as a result, the initial rainfall resistance (water resistance, etc.) of the coating film obtained is reduced. In the case of using a chain transfer agent, it is desirable to reduce the amount used as much as possible because it may reduce the initial dryness and toughness, washing resistance, adhesion resistance and the like.

  Here, examples of the buffer include sodium acetate, ammonium acetate, dibasic sodium phosphate, and the like. Two or more of these may be used in combination.

  Any auxiliary emulsifier can be used as long as it is known to those skilled in the art as being usable for emulsion polymerization. Accordingly, the auxiliary emulsifier is appropriately selected from known ones such as anionic, cationic, and nonionic surfactants, water-soluble polymers having protective colloid ability other than polyvinyl alcohol, and water-soluble oligomers. be able to.

  Preferred specific examples of the surfactant include, for example, anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, and nonions such as those having a pluronic structure and those having a polyoxyethylene structure. Surfactants. A reactive surfactant having a radical polymerizable unsaturated bond in the structure can also be used as the surfactant.

  By using an emulsifier, the emulsion polymerization can proceed smoothly, the polymerization can be easily controlled, and the generation of coarse particles and block-like substances generated during the polymerization can be suppressed. If it is used as a large amount, the particles may be agglomerated at the time of drying, and the re-emulsification property may be lowered. Therefore, when a surfactant is used as an emulsifier, the amount used is preferably an auxiliary amount for the PVA resin, that is, as small as possible.

  Examples of water-soluble polymers having protective colloid ability other than PVA-based resins include hydroxyethyl cellulose, polyvinyl pyrrolidone, and methyl cellulose. These are effective in changing the viscosity when the obtained re-emulsifiable resin powder is re-emulsified and used. However, since the re-emulsification property of the re-emulsifiable resin powder may be reduced depending on the amount of use, it may be used in an amount that does not reduce the re-emulsification property of the re-emulsification resin powder. desirable.

  As the water-soluble oligomer, for example, a polymer or copolymer having a hydrophilic group such as a sulfonic acid group, a carboxyl group, a hydroxyl group, and an alkylene glycol group and having a degree of polymerization of about 10 to 500 is preferably exemplified.

  Specific examples of water-soluble oligomers include, for example, amide copolymers such as 2-methacrylamide-2-methylpropanesulfonic acid copolymer, sodium methacrylate-4-styrenesulfonate copolymer, styrene / maleic acid copolymer. Examples thereof include a polymer, a melamine sulfonic acid formaldehyde condensate, and a poly (meth) acrylate. Specific examples include monomers having a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkylene glycol group, and water-soluble oligomers obtained by previously copolymerizing a radical polymerizable reactive emulsifier alone or with other monomers. It is done. In the present invention, among these, 2-methacrylamide-2-methylpropanesulfonic acid copolymer, methacrylic acid, in that re-emulsifying property can be imparted, and in terms of mixing stability with pigments and fillers such as calcium carbonate. Sodium-4-styrene sulfonate copolymer is preferred. As the water-soluble oligomer, those previously polymerized before starting the emulsion polymerization may be used, or commercially available products may be used. Two or more of these may be used in combination.

  Moreover, as a plasticizer, the adipate type plasticizer, the phthalic acid type plasticizer, the phosphoric acid type plasticizer, etc. which are generally used for paints and adhesives can be used. A film-forming aid can also be used.

  The amount of these other components used is not particularly limited as long as the object of the present invention is not impaired, and can be appropriately selected according to the object.

  In the present invention, various additives may be further added to the aqueous synthetic resin emulsion (A) obtained by emulsion polymerization of the ethylenically unsaturated monomer component, if necessary. Examples of such additives include organic pigments, inorganic pigments, water-soluble additives, dispersants such as pigments and fillers, thickeners, pH adjusters, preservatives, and antioxidants. When these are powders / powder, they may be added to the re-emulsifiable resin powder (I) obtained by spray-drying the aqueous synthetic resin emulsion (A).

  Water-soluble additives include hydroxyethyl celluloses, methyl celluloses, starch derivatives, polyvinyl pyrrolidones, polyethylene oxides, water-soluble alkyd resins, water-soluble phenol resins, water-soluble urea resins, water-soluble additives, depending on the application of the resin powder. Water-soluble melamine resin, water-soluble guanamine resin, water-soluble naphthalenesulfonic acid resin, water-soluble amino resin, water-soluble polyamide resin, water-soluble acrylic resin, water-soluble polycarboxylic acid resin, water-soluble polyester resin, water-soluble polyurethane resin, water-soluble Examples thereof include a polyol resin and a water-soluble epoxy resin. If it is a liquid water-soluble additive, it is preferably added to the aqueous synthetic resin emulsion (A) before spray drying and then spray-dried to obtain a re-emulsifiable resin powder (I). If so, it may be dissolved once and then added to the aqueous synthetic resin emulsion (A) before spray drying, or may be added directly to the resin powder after spray drying. Two or more of these may be used in combination.

  A resin powder containing at least one of unmodified PVA, acetoacetyl group-modified PVA and carbonyl group-modified PVA, and / or an acetoacetyl group and carbonyl group-containing monomer, which are effective for further improving the re-emulsifying property of the resin powder In the resin powder obtained by copolymerization, after re-emulsifying and returning to the emulsion state, isocyanate compounds, aziridine compounds, epoxy group-containing compounds, amine compounds, aldehyde compounds used as these crosslinking agents depending on the application Further, it can be used in appropriate combination with a methylolmelamine polymer or the like.

  The re-emulsifiable resin powder (I) in the present invention is composed of an emulsion containing the synthetic resin emulsion (A) and the re-emulsification improver (B). When it is dispersed and emulsified in water, it is preferable from the viewpoint that the re-emulsification property in water can be improved.

  As the re-emulsification improver (B), a water-soluble resin can be used, and the PVA-based resin (b) is particularly preferable from the viewpoint that the re-emulsification property to water can be improved.

  The PVA resin (b) may be the same as or different from the PVA resin (a) used as a protective colloid in the emulsion polymerization process.

  During polymerization, a PVA resin having a high degree of polymerization is difficult to use because of its polymerization stability, but even such a PVA resin can be used without any problems as long as it is added after polymerization. However, those that are not easily soluble in water may adversely affect the re-emulsification properties, so it is desirable to use them after confirming the solubility in water in advance.

  The average saponification degree of the PVA-based resin (b) is preferably 85 mol% or more, and more preferably 87 mol% or more. The upper limit of the average saponification degree is not particularly limited, but is preferably 99.5 mol% or less, and more preferably 95 mol% or less. If the average saponification degree is too small, the water resistance tends to be remarkably lowered. If the average saponification degree is too large, the water resistance is improved, but the re-emulsification property to water tends to be deteriorated.

  Moreover, it is preferable that it is 50-3000, as for the average degree of polymerization of PVA-type resin (b), it is more preferable that it is 200-2000, and it is further more preferable that it is 300-600. If the average degree of polymerization is too small, the water resistance tends to decrease, and if it is too large, the re-emulsification property tends to decrease.

  The PVA resin (b) is preferably at least one selected from the group consisting of an unmodified PVA resin and a modified PVA resin.

  Examples of modified PVA resins include carboxylic acid modified PVA resins, sulfonic acid modified PVA resins, acetoacetyl group modified PVA resins, mercapto group modified PVA resins, carbonyl group modified PVA resins, and silanol group modified PVA resins. Resin, amino group-modified PVA resin, cation group-modified PVA resin, amide group-modified PVA resin, and PVA resin having a 1,2-diol bond in the side chain. An acetyl group-modified PVA resin and a carbonyl group-modified PVA resin are preferred. In the case of using an acetoacetyl group-modified PVA resin or a carbonyl group-modified PVA resin, it is more preferable that the crosslinking agent (III) described later contains a hydrazide compound that can react with these.

  Such an acetoacetyl group-modified PVA resin has a degree of acetoacetylation of 0.01 to 10 mol% (preferably 0.03 to 6 mol%), and a carbonyl group-modified PVA resin has a degree of carbonyl group modification of 0. It is preferably at least one selected from the group consisting of 5 to 10 mol% (preferably 1 to 5 mol%).

  When using a water-soluble resin as the re-emulsification improver (B), it is usually preferable to add the water-soluble resin to the aqueous synthetic resin emulsion (A) after emulsion polymerization and before drying. You may add to re-emulsifiable resin powder (I) obtained by spray-drying according to the kind of water-soluble resin, addition amount, and a use.

  The amount of the re-emulsification improver (B) used is preferably 2 to 30% by weight, and preferably 5 to 20% by weight, based on the solid content of the aqueous synthetic resin emulsion (A) before drying. More preferred. If the amount used is too small, the re-emulsification tends to be insufficient, and if too much, the water resistance of the re-emulsifiable resin powder tends to be insufficient.

  Next, the manufacturing method of the re-emulsifiable resin powder (I) of this invention is demonstrated.

  The re-emulsifiable resin powder (I) according to the present invention is obtained by emulsion polymerization of an ethylenically unsaturated monomer component containing a hydrophobic monomer, preferably further a functional monomer, using the PVA resin (a) as a protective colloid, An aqueous synthetic resin emulsion (A) is obtained, which is a resin powder obtained by drying, preferably spray drying, and the above-mentioned re-emulsification improver (B), silica (II) described later, and crosslinking agent (III). It can also be made to contain.

  The method for emulsion polymerization is not particularly limited. For example, water, PVA-based resin (a1), and other protective colloid as necessary are charged into a reaction can, and the temperature is raised to obtain an ethylenically unsaturated monomer and a polymerization initiator. Dropping monomer dropping type emulsion polymerization method; and the dropping monomer dispersing and emulsifying in advance with a protective colloid and water, then dropping the added monomer dropping type emulsion polymerization method, etc. From the standpoint of properties and the like, the monomer dropping type emulsion polymerization method is convenient.

  Usually, the emulsion polymerization is carried out using other components such as a polymerization initiator, a polymerization regulator, and an auxiliary emulsifier as needed in addition to the protective colloid, the emulsifier and the copolymerizable monomer component. The polymerization reaction conditions are not particularly limited, and can be appropriately selected according to the type and purpose of the copolymerizable monomer.

  The emulsion polymerization process will be described more specifically. However, it is not limited to this.

  First, water, protective colloid and, if necessary, auxiliary emulsifier are charged into the reaction can, and after heating this (for example, 65 to 90 ° C.), a part of the copolymerizable monomer component and a polymerization initiator are added to the reaction can. Then, initial polymerization is carried out. Next, the remaining copolymerizable monomer components are added to the reaction can in one batch or dropwise, and polymerization is allowed to proceed while further adding a polymerization initiator as necessary. When it is determined that the polymerization reaction is completed, the reaction can is cooled and the target aqueous synthetic resin emulsion (A) can be taken out.

  In the present invention, the aqueous synthetic resin emulsion (A) obtained by emulsion polymerization is typically uniform milky white, and its average particle size is preferably 0.2 to 2.0 μm. It is more preferable that it is 3-1.5 micrometers.

  Here, the average particle diameter of the emulsion can be measured by a conventional method, for example, a laser analysis / scattering particle size distribution measuring apparatus “LA-910” (manufactured by Horiba, Ltd.).

  In the present invention, the re-emulsifiable resin powder (I) can be obtained by drying the aqueous synthetic resin emulsion (A) obtained by the emulsion polymerization.

  The drying method is not particularly limited, and examples thereof include spray drying, freeze drying, and hot air drying after coagulation. Among these, spray drying is preferable from the viewpoint of production cost and energy saving.

  In the case of spray-drying, the spraying form is not particularly limited, and for example, it can be carried out by a disk type, a nozzle type or the like. Examples of the heat source for spray drying include hot air and heated steam. The conditions for spray drying can be appropriately selected according to the size and type of the spray dryer, the solid content of the aqueous emulsion, the viscosity, the flow rate, and the like. The temperature of spray drying is usually about 80 to 150 ° C.

  The spray drying process will be described with further specific examples. First, the solid content in the synthetic resin emulsion is adjusted, and this is continuously supplied from the nozzle of the spray dryer, and the mist is dried with warm air. To powder. In some cases, it is also possible to preheat the adjusted spray liquid before spraying, continuously supply it from the nozzle, and dry the atomized liquid with warm air to form a powder. Heating increases the drying speed and enables highly non-volatile differentiation of the spray liquid as the viscosity of the spray liquid decreases, contributing to a reduction in production costs.

  In the present invention, the anti-caking agent is mixed with the aqueous emulsion (A), mixed with the re-emulsifiable resin powder (I) after spray drying, or the aqueous synthetic resin emulsion (A) during spray drying. It can be used together by spraying from another nozzle.

  By adding an anti-caking agent, it is possible to prevent particles from caking and agglomerating and blocking during storage in a state where the resin powder is coated with the anti-caking agent.

  As the anti-caking agent, known inert inorganic or organic powders, for example, calcium carbonate, talc, clay, dolomite, anhydrous silicic acid, alumina white and the like can be used as the inorganic powder. Among these, anhydrous silicic acid, calcium carbonate, clay and the like are preferable. As the organic powder, a resin powder obtained by spray-drying an aqueous emulsion having a glass transition temperature of 70 ° C. or higher of the synthetic resin can also be used as an anti-caking agent. It is preferable that the usage-amount of an anti-caking agent is about 5 to 30 weight% with respect to the re-emulsifiable resin powder (I) obtained. Moreover, combined use of organic powder and inorganic powder is also possible.

  The re-emulsifiable synthetic resin powder composition of the present invention contains silica (II) together with the re-emulsifiable resin powder (I).

  In the present invention, silica (II) is added for the purpose of preventing skinning (drying delay), improving the workability of the trowel, and improving the patterning property.

  Here, trowel workability / patterning by trowels, etc. means that, especially in exterior finishing coating materials for exterior, when patterning with trowels etc. after coating, the coating surface with trowels etc. after 30 minutes of coating is applied. It refers to patterning.

BET specific surface area of such a silica (II) is preferably 50 to 400 m ² / g, more preferably 120~380m ² / g, and particularly preferably a 200~380m ² / g. If the BET specific surface area is too small, the anti-skinning (drying delay) effect tends to decrease. If the BET specific surface area is too large, the drying of the film is delayed, the initial drying resistance (water resistance, etc.), and the initial development of coating film hardness. Tends to decrease.

  In addition, the silica (II) is refined from the viewpoint that the particle size of the primary particles is fine and small to the nano-size level, and that there are many silanol groups that are easy to disperse and that are present on the particle surface and easily adsorb water. Fumed silica produced by hydrolyzing silicon tetrachloride in an oxygen and hydrogen flame is preferred.

  The amount of silica (II) used is preferably 1 to 15% by weight, more preferably 3 to 10% by weight, and even more preferably 4 to 6% by weight with respect to the re-emulsifiable resin powder (I). If the amount is too small, the anti-skinning (drying delay) effect tends to decrease. If the amount is too large, the anti-skinning (drying delay) effect is improved, but the drying is delayed too much and the initial rainfall resistance (water resistance, etc.) There is a tendency for the initial dryness of the coating film hardness to decrease.

  Furthermore, a hydrophobic type surface-treated with silicone oil, dimethyldichlorosilane or the like can also be used.

  The re-emulsifiable synthetic resin powder composition of the present invention comprises a cross-linking agent (III) together with the re-emulsifiable resin powder (I) and silica (II).

  As the crosslinking agent (III), the unmodified and / or modified PVA-based resin to be used, and a re-emulsifiable resin powder composed of a copolymerized carbonyl group and / or acetoacetyl group-containing functional monomer are stably mixed, At least one selected from the group consisting of a polyvalent metal salt, a tertiary or quaternary cationic resin and a hydrazide compound is obtained because, when re-emulsified in water, cross-linking proceeds promptly and the intended coating film is obtained. It is preferable to contain a cross-linking agent such as seed powder / powder / granular. When the cross-linking agent is a liquid product, it can be used after being powdered.

  Examples of the polyvalent metal salt include calcium, aluminum, magnesium, zirconium hydroxide or oxide, aluminum chloride and sulfate, zirconium nitrate, and the like.

  Examples of the tertiary or quaternary cationic resin include polydiallylamine and modified products thereof. Among these, a tertiary amine of polydiallylamine, a quaternary ammonium salt of polydiallylamine, and an acrylamide copolymer type thereof are more preferable. These tertiary or quaternary cationic resins have not only a function as a cross-linking agent but also a function as a dispersant when producing a building finish coating material or a powder coating material, and also have a water reducing effect. Accordingly, the non-volatile content of the architectural finish coating material and the powder paint is increased, and the drying property can be improved.

  Examples of the hydrazide compound include adipic acid dihydrazide, polyhydrazide compound, carbohydrazide and the like.

  These polyvalent metal salts do not necessarily need to be water-soluble, and may be easily dispersed in water during use. Further, these crosslinking agents (III) may be used in combination due to the effect on the resulting coating film.

  When the synthetic resin powder contains a carbonyl group and / or acetoacetyl group-modified PVA and / or a carbonyl group and / or an acetoacetyl group monomer, it is preferable to use a hydrazide compound as a crosslinking agent. You may use together with a valent metal salt, a tertiary, or a quaternary cationic resin.

  The amount of the crosslinking agent (III) used is preferably 0.5 to 30% by weight based on the re-emulsifiable resin powder (I) in the case of a polyvalent metal salt and a tertiary or quaternary cationic resin. 3 to 15 weight% is more preferable, and 5 to 10 weight% is further more preferable. If the amount is too small, there is a tendency that the effect of improving the coating properties such as initial rainfall resistance (water resistance, etc.), initial drying property of coating film hardness, early drying property in winter, etc. cannot be fully expressed. There is no effect in further improving the physical properties of the coating film. In particular, in the case of a polyvalent metal salt, crosslinking tends to proceed too much and the coating film itself tends to be brittle. In the case of a tertiary or quaternary cationic resin, the water resistance tends to decrease.

  In the case of a hydrazide compound, it may be appropriately selected depending on the amount of carbonyl group and / or acetoacetyl group in the resin that crosslinks with these compounds, and is 0.1 to 10 weights relative to the re-emulsifiable resin powder (I). % Is preferable, and 0.5 to 5% by weight is more preferable. If the amount is too small, the crosslinking effect tends to be insufficient, and if the amount is too large, no further effect can be expected.

  Further, when the re-emulsifiable resin powder composition of the present invention or an aqueous emulsion re-emulsified in water is used as an adhesive for wood / wood adhesion, the crosslinking agent (III) is particularly limited. However, an isocyanate compound or a prepolymer thereof, an epoxy compound or a prepolymer thereof is preferably used.

  The re-emulsifiable resin powder composition of the present invention is particularly excellent for use in building finishing materials and powder coatings. And, especially in the case of exterior building finish coating materials, to obtain an excellent aqueous emulsion that prevents skinning even in the summer when the coating film surface dries quickly and enables the coating surface to be patterned with a trowel after coating. Re-emulsifiable resin powder, and in addition, for admixtures for hydraulic materials such as cement and gypsum (for mortars such as for base preparations, for tile adhesives, putty, etc.), wood or wood It can be used for various applications such as adhesives for paper and paper. More preferably, it is useful as a resin powder for exterior finishes and powder coatings.

  For building finishing materials and powder paints, inorganic materials such as calcium carbonate, clay, talc, dolomite, mica, titanium oxide, and silica sand that are usually used for this kind of application can be used. Hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, starch derivatives, inorganic powder thickeners / viscosity improvers, crack generation inhibitors such as pulp powder, and the like can also be used. Hydraulic materials such as cement and gypsum can be used to the extent that they do not affect the finished state, such as color tone.

  Depending on the application and use conditions, it may be used after re-emulsifying in water and returning to an aqueous emulsion.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.

  In the examples, “parts” and “%” mean weight basis unless otherwise specified.

<Evaluation method>
(Measurement of graft ratio)
In the aqueous synthetic resin emulsions 1 to 7 obtained in Synthesis Examples 1 to 7, using the pre-addition emulsion of PVA aqueous solution for post-addition, drying was performed at 40 ° C. for 16 hours to form a film having a thickness of about 0.5 mm. It was prepared and left at 23 ° C. × 65% RH for 2 days. When the film is extracted in boiling water for 8 hours and then extracted with acetone for 8 hours, the film dry weight before extraction is W ₁ (g), and the film dry weight after extraction is W ₂ (g And the value obtained from the following formula was taken as the graft ratio.
Graft ratio (% by weight) = (W ₂ ) / (W ₁ ) × 100
Film dry weight after extraction (W ₂ ): Weight when the sample after extraction was dried at 105 ° C. for 1 hour,
Film dry weight before extraction (W ₁ ): A sample different from the extraction test sample is dried in advance at 105 ° C. for 1 hour, and corrected from the volatile content ratio to calculate the film dry weight of the extracted sample. .

(Drying initial precipitation resistance (water resistance) of coating film, initial development of coating film hardness)
The architectural finish coating materials obtained in Reference Examples 1 to 10, Example 1 and Comparative Examples 1 and 2 were applied to a slate plate with a 3 mm applicator and dried at room temperature. After drying for 4 hours, it was immersed in water for 2 hours and rubbed 10 times with a finger strongly, and the finished state of the coated surface was evaluated according to the following criteria. In this test, it was regarded as a substitute test for the initial dry rain resistance (water resistance) and the initial dryness of the coating film hardness, and the evaluation AB was accepted as a practically satisfactory level.
A: The surface of the coating film is hard, the coating film is hardly removed even by rubbing with a finger, and the white color of the emulsion does not flow out.
B: Although the surface of the coating film is hard, the surface is slightly removed when rubbed with a finger, and the white color of the emulsion flows out slightly.
C: The surface of the coating film is slightly soft, the surface is removed when rubbed with a finger, and the white color of the emulsion flows out.
D: The coating film absorbs water and is in a brilliant state. When rubbed with a finger, the entire surface is removed from the base and the white color of the emulsion flows out.

(Water resistance / undercoat adhesion of coating film)
The architectural finish coating materials obtained in Reference Examples 1 to 10, Example 1 and Comparative Examples 1 and 2 were applied to a slate plate with a 3 mm applicator and dried at room temperature. After drying for 24 hours, it was immersed in water for 6 hours and 24 hours and rubbed 10 times with a dishwashing sponge, and the finished state of the coated surface was evaluated according to the following criteria. Furthermore, the coating film was shaved with a spatula, and the peeling method of the coating film, adhesion to the ground, etc. were visually evaluated according to the following criteria. In this test, the water resistance of the coating film was used as a substitute test for the base adhesion, and the evaluation A-B was accepted as a practically acceptable level.
A: The coating film surface is hard, and the coating film cannot be removed by rubbing with a sponge. Very strong force is needed to scrape off the coating film with a spatula and it adheres well to the substrate.
B: The coating film surface is hard, and the coating film can hardly be removed by rubbing with a sponge, but a little force is required to scrape the coating film with a spatula.
C: The surface of the coating film is hard, and the coating film can hardly be removed by rubbing with a sponge. However, since the coating film is brittle, no significant force is required for scraping with a spatula.

(Patternability after coating (trowel workability, prevention of skinning))
The architectural finish coating materials obtained in Reference Examples 1 to 10, Example 1 and Comparative Examples 1 and 2 were applied to a slate plate with a trowel so that the wet thickness was 3 mm, and dried at room temperature for 1 hour and 2 hours later. The surface of the coated surface of the film and the possibility of patterning by the trowel were evaluated according to the following criteria. In this test, it was regarded as a substitute test for the patterning property (coating workability) after coating, and the evaluation A-B was accepted as a practically satisfactory level.
A: There is no skin on the coating surface, and patterning with a trowel is as easy as coating.
B: Although some skinning is recognized on the coating surface, patterning with a trowel is easy.
C: Skinning is observed on the painted surface, but patterning with a trowel is possible.
D: Skinning is observed on the painted surface, and it is difficult to pattern with a trowel.

Synthesis Example 1 (Production of aqueous synthetic resin emulsion 1)
In a 2L stainless steel reaction can equipped with a stirrer and a reflux condenser, 670 parts of water and acetoacetyl group-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average saponification degree: about 98 mol%, average 46 parts of polymerization degree: about 400, acetoacetylation degree: 0.5 mol%) was charged, and the reaction vessel was heated to 85 ° C. to dissolve the acetoacetyl group-modified PVA in water. Next, the temperature of the reactor was kept at 80 ° C., and mixed monomers (165 parts of butyl acrylate / 263 parts of styrene / 2230 parts of 2-ethylhexyl acrylate = 25/40/35), (Weight ratio) (hydrophobic monomer = 100%)) was added and an initial polymerization reaction was carried out for 1 hour using ammonium persulfate as a polymerization initiator. Next, the remaining mixed monomer was dropped into the reaction vessel over 4 hours, and dropping polymerization was allowed to proceed while further adding ammonium persulfate as a polymerization initiator. After completion of the dropwise addition, the mixture was aged at the same temperature for 1 hour, and then partially saponified PVA having an average polymerization degree of 500 and an average saponification degree of 88 mol% (“GOHSENOL GL05” (trade name), manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). 276 parts of a 20% aqueous solution was added here and stirred thoroughly. As a result, an aqueous synthetic resin emulsion 1 (average particle size 0.45 μm) having a nonvolatile content of 46% was obtained. The graft ratio of the obtained aqueous synthetic resin emulsion 1 was 78% by weight.

  The calculated glass transition temperature (Tg) of the synthetic resin composed of this monomer component (butyl acrylate / styrene / 2-ethylhexyl acrylate = 25/40/35 (weight ratio)) is the Tg of each homopolymer is −52 ° C. , 100 ° C., −70 ° C., it is −18 ° C.

Synthesis Example 2 (Production of aqueous synthetic resin emulsion 2)
Except for changing the type and composition ratio of the mixed monomer to butyl acrylate / styrene / diacetone acrylamide = 60/37/3 (weight ratio) (hydrophobic monomer = 97%) Synthetic resin emulsion 2 (average particle size 0.43 μm) was produced. The graft ratio of the obtained aqueous synthetic resin emulsion 2 was 82% by weight.

  The calculated glass transition temperature (Tg) of the synthetic resin composed of this monomer component (butyl acrylate / styrene / diacetone acrylamide = 60/37/3 (weight ratio)) is the Tg of each homopolymer at −52 ° C. , 100 ° C., 65 ° C., it is −3 ° C.

Synthesis Example 3 (Production of aqueous synthetic resin emulsion 3)
Emulsion 3 (average particle size 0. 0) was the same as Synthesis Example 1 except that the type and composition ratio of the mixed monomer were changed to butyl acrylate / styrene = 46/54 (weight ratio) (hydrophobic monomer = 100%). 43 μm) was produced. The graft ratio of the obtained aqueous synthetic resin emulsion 3 was 65% by weight.

  The calculated glass transition temperature (Tg) of the synthetic resin composed of this monomer component (butyl acrylate / styrene = 46/54 (weight ratio)) is as follows when the Tg of each homopolymer is −52 ° C. and 100 ° C. 10 ° C.

  However, for the purpose of adjusting the minimum film forming temperature, 3% of dibutyl phthalate as a plasticizer was added to the resin content.

Synthesis Example 4 (Production of aqueous synthetic resin emulsion 4)
Emulsion 4 (average particle size) was the same as in Synthesis Example 1 except that the type and composition ratio of the mixed monomer were changed to methyl methacrylate / 2-ethylhexyl acrylate = 50/50 (weight ratio) (hydrophobic monomer = 50%). Diameter 0.51 μm) was produced. The graft ratio of the obtained aqueous synthetic resin emulsion 4 was 78% by weight.

  The calculated glass transition temperature (Tg) of the synthetic resin composed of this main monomer (methyl methacrylate / 2-ethylhexyl acrylate = 50/50 (weight ratio)) is 105 ° C. and −70 ° C. for the Tg of each homopolymer. In this case, it is −9 ° C.

Synthesis Example 5 (Production of aqueous synthetic resin emulsion 5)
A 20% aqueous solution of PVA to be added after completion of dropping is an acetoacetyl group-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having an average degree of polymerization of 500, an average degree of saponification of 99.1 mol%, and an acetoacetylation degree of 5 mol%. Emulsion 5 (average particle size 0.45 μm) was produced in the same manner as in Synthesis Example 1 except that the amount was changed to 276 parts. The graft ratio of the obtained aqueous synthetic resin emulsion 5 was 75% by weight.

Synthesis Example 6 (Production of aqueous synthetic resin emulsion 6)
Side chain of acetoacetyl group-modified PVA of Synthesis Example 1 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average saponification degree: about 98 mol%, average polymerization degree: about 400, acetoacetylation degree: 0.5 mol%) PVA having a 1,2-diol bond (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average degree of saponification: about 99.1 mol%, average degree of polymerization: about 300, containing 1,2-diol bonds in the side chain) Emulsion 6 (average particle size 0.46 μm) was produced in the same manner as in Synthesis Example 1 except that the amount was changed to 8 mol%. The graft ratio of the obtained aqueous synthetic resin emulsion was 80%.

Synthesis Example 7 (Production of aqueous synthetic resin emulsion 7)
The same as Synthesis Example 1 except that the type and composition ratio of the mixed monomer were changed to methyl methacrylate / 2-methoxyethyl acrylate / 2-ethylhexyl acrylate = 45/30/25 (weight ratio) (hydrophobic monomer = 25%). Thus, Emulsion 7 (average particle size 0.45 μm) was produced. The graft ratio of the obtained aqueous synthetic resin emulsion 7 was 50% by weight.

  The calculated glass transition temperature (Tg) of the synthetic resin composed of this monomer component (methyl methacrylate / 2-methoxyethyl acrylate / 2-ethylhexyl acrylate = 45/30/25 (weight ratio)) is the Tg of each homopolymer. Is -8 ° C, when 100 ° C, -50 ° C, and -70 ° C.

Production Examples 1 to 7 (Production of re-emulsifiable resin powder (I))
The non-volatile content of emulsions 1-7 obtained in Synthesis Examples 1-7 was adjusted, and in the presence of fine silicic acid powder having an average particle size of about 0.02 μm as an anti-caking agent (relative to re-emulsifiable resin powder (I) 15 wt%), a heat source was used as hot air by a nozzle type spray dryer, and spray drying was performed under hot air at 150 ° C. to obtain resin powders 1 to 7.

Reference example 1
Table 1 shows 4 parts by weight of fumed silica (Leonol QS-30 / Tokuyama, BET specific surface area: 300 m ² / g) with respect to 100 parts by weight of the resin powder 1 in the resin powder 1 obtained in Production Example 1. A cross-linking agent, the following thickeners, fillers, antifoaming agents, etc. are prepared in advance, and this is dispersed in water so that the viscosity is suitable for iron coating (a slate plate coated with a iron to a thickness of about 5 mm). The building finish coating material was obtained by adjusting the viscosity to such a level that the coating film does not sag even when it is stood vertically and allowed to stand. Table 1 shows the evaluation results of the initial drying resistance (water resistance) of the coating film, the initial expression of drying of the coating film hardness, the water resistance / base adhesion of the coating film, and the patterning property after coating.

Resin powder 1 30 parts by weight Thickener Tyroze MH30000YP6 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 parts by weight Filler Titanium oxide (Taipeke R-820 / Ishihara Sangyo Co., Ltd.) 19 parts by weight
12.5 parts by weight of N, N light kaolin clay (Tsuchiya Kaolin Industry Co., Ltd.)
Takara Mica 601 (Tsuchiya Kaolin Industry Co., Ltd.) 7.5 parts by weight
NS # 100 (manufactured by Nitto Flour Chemical Co., Ltd.) 26 parts by weight
Silica sand No. 7 95 parts by weight Other pulp powder 2.5 parts by weight
Powder antifoaming agent (Adecanate 107F / ADEKA) 1 part by weight Water 100 parts by weight Total 294 parts by weight

Reference Examples 2 to 10 and Example 1
In the same manner as in Reference Example 1, architectural finishing coating materials of Reference Examples 2 to 10 and Example 1 were obtained using the resin powders 2 to 6 obtained in Production Examples 2 to 6. Table 1 shows the evaluation results of the initial drying resistance (water resistance) of the coating film, the initial expression of drying of the coating film hardness, the water resistance / base adhesion of the coating film, and the patterning property after coating.

Comparative Example 1
In the same manner as in Reference Example 1, an architectural finish coating material was obtained using the resin powder 7 obtained in Production Example 7. Table 1 shows the evaluation results of the initial drying resistance (water resistance) of the coating film, the initial expression of drying of the coating film hardness, the water resistance / base adhesion of the coating film, and the patterning property after coating.

Comparative Example 2
In Reference Example 1, an architectural finishing coating material was obtained in the same manner except that fumed silica was not blended. Table 1 shows the evaluation results of the initial drying resistance (water resistance) of the coating film, the initial expression of drying of the coating film hardness, the water resistance / base adhesion of the coating film, and the patterning property after coating.

  The re-emulsifiable synthetic resin powder composition of the present invention is re-emulsified in water to form an aqueous emulsion. In particular, it is suitable for exterior finish coating materials and powder coatings for exteriors, such as initial rainfall resistance (water resistance, etc.) and coating film hardness. Excellent initial dryness and early drying in winter, and especially for exterior finish coating materials for exteriors, prevents skinning even in the summer when the coating film surface dries quickly, so that the surface can be coated with a trowel after coating. It has an excellent effect as a resin powder that can be easily patterned, and in addition, for adhesives for hydraulic materials such as cement and gypsum, for wood or wood, for paper, etc. It is useful for various applications such as. In particular, since the product of the present invention is a re-emulsifiable synthetic resin powder, in addition to the powder / powder that forms these application compositions, the desired product can be produced simply by kneading with water as a complete preparation. be able to.

Claims (10)

A synthetic resin obtained by polymerizing an ethylenically unsaturated monomer component containing a hydrophobic monomer in an amount of 30% by weight or more based on the total monomer components and containing a styrene monomer has a 1,2-diol bond in the side chain. It contains a re-emulsifiable resin powder (I) composed of an aqueous synthetic resin emulsion (A) dispersed and stabilized with an alcohol-based resin (a 2 ), silica (II), and a crosslinking agent (III). Re-emulsifiable resin powder composition for hydraulic material . The ethylenically unsaturated monomer component is selected from the group consisting of allyl group-containing monomers, glycidyl group-containing monomers, hydrolyzable silyl group-containing monomers, acetoacetyl group-containing monomers, vinyl group-containing monomers, and carbonyl group-containing monomers. The re-emulsifiable resin powder composition for a hydraulic material according to claim 1, comprising the above functional monomer. Re-emulsifiable resin powder (I) is an aqueous synthetic resin emulsion (A) in claim 1 or 2 for a hydraulic material re-emulsifiable according to characterized in that it consists of an emulsion comprising a re-emulsifiable improver (B) Resin powder composition. The hydraulic material according to claim 3, wherein the re-emulsification improver (B) is a polyvinyl alcohol resin (b) having an average degree of saponification of 85 mol% or more and an average degree of polymerization of 50 to 3000. use re-emulsifiable resin powder composition. The polyvinyl alcohol resin (b) is at least one selected from the group consisting of an acetoacetyl group-modified polyvinyl alcohol resin, a carbonyl group modified polyvinyl alcohol resin, and a polyvinyl alcohol resin having a 1,2-diol bond in the side chain. The re-emulsifiable resin powder composition for a hydraulic material according to claim 4, which is a seed. Silica (II) is, for a hydraulic material re-emulsifiable resin powder composition according to any one of claims 1 to 5, characterized in that a silica having a BET specific surface area of 50 to 400 m ² / g. Crosslinking agent (III) is a polyvalent metal salt, to any one of claims 1 to 6, characterized in that at least one selected from the group consisting of tertiary or quaternary cationic resin and hydrazide compounds The re-emulsifiable resin powder composition for hydraulic materials as described. Claim 1-7 or as described in for a hydraulic material re-emulsifiable resin powder composition redispersible and hydraulic material for aqueous emulsion, characterized by comprising the. For a hydraulic material re-emulsifiable resin powder composition or building finish materials, characterized by comprising a hydraulic material for aqueous emulsion as claimed in claim 8 according to any one of claims 1-7. Aqueous for hydraulic material for a hydraulic material re-emulsifiable resins powder compositions or claim 8, wherein according to any one of claims 1 to 7 architectural finish materials, powder coating formulation consisting of a hydraulic material An architectural finish coating material comprising an emulsion.