JP2013209235A - Re-emulsifiable synthetic resin powder composition for polymer cement and polymer cement mortar using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide re-emulsifiable synthetic resin powder for polymer cement that has excellent miscibility (mixing stability, fluidity, bonding strength, bending strength, compressive strength, low water-absorbing property, low water permeability, and the like) with cement and causes no surface whitening even when polymer cement mortar is applied under a low temperature condition.SOLUTION: Re-emulsifiable synthetic resin powder composition for polymer cement includes re-emulsifiable synthetic resin powder (A) and inorganic fine particles (B). Inorganic fine particles (B1) whose average grain size is equal to or less than 10 μm and inorganic fine particles (B2) whose average grain size is equal to or larger than 10 μm are used for the inorganic fine particles (B).

Description

  The present invention relates to a re-emulsifiable synthetic resin powder composition for polymer cement, and more specifically, a powdered synthetic resin emulsion that can be suitably used as mortar or concrete by mixing with cement to form polymer cement. It is about.

  Conventionally, an anti-blocking agent has been used in emulsion powders for polymer cements for the purpose of preventing bonding between particles (blocking). As the anti-blocking agent, mortars obtained using polymer cements, In consideration of physical properties such as fluidity of concrete, inorganic fine particles having a relatively small particle size have been used.

  For example, Patent Document 1 discloses an emulsion having a vinyl alcohol polymer as a dispersant and a polymer having an unsaturated monomer unit selected from an ethylenically unsaturated monomer and a diene monomer as a dispersoid. (A) is a vinyl alcohol polymer containing a polyoxyalkylene group in the side chain, the viscosity average polymerization degree of the vinyl alcohol polymer is 100 to 3000, and the saponification degree is 70.0 to 99.99. An anti-blocking agent having an average particle diameter of about 2 μm is further added to the composition in which the polyoxyalkylene-vinyl alcohol polymer (B) having a polyoxyalkylene modification amount of 0.1 to 10 mol% is blended. It is described that the re-emulsifiable synthetic resin powder obtained by blending and drying can be compatible with water-reducing and thickening properties when mixed with a hydraulic substance such as cement mortar. It has been.

JP 2010-235763 A

In the study on the conventional re-emulsifiable synthetic resin powder, the use of an anti-blocking agent when pulverizing the synthetic resin emulsion as in Patent Document 1 has been studied. There has been no investigation of powdering a synthetic resin emulsion, focusing on the diameter, etc., and taking into account the effect on the final performance of hydraulic materials such as cement.
In recent years, with regard to re-emulsifiable synthetic resin powder blended with an anti-blocking agent, kneading with cement at low temperatures in winter, when mortar and concrete are applied, the curing rate becomes extremely slow, The anti-blocking agent, which is fine particles, floats on the surface of mortar and concrete coatings applied at a low temperature due to surface migration, causing whitening of the surface of the mortar and concrete.

  Therefore, in the present invention, under such a background, it is excellent in miscibility with cement (mixing stability, fluidity, adhesive strength, bending strength, compressive strength, low water absorption, low water permeability, etc.) and at lower temperatures. It is an object of the present invention to provide a re-emulsifiable synthetic resin powder for polymer cement that does not cause whitening of the surface even when polymer cement mortar is applied.

  However, the present inventors have conducted extensive studies in view of such circumstances, and as a result, in addition to the inorganic particles having a small particle size that have been blended in the re-emulsifiable synthetic resin powder in order to impart blocking performance, the particle size is further increased. By blending large inorganic fine particles, it was found that surface whitening does not occur when mortar or concrete is applied at low temperatures, and the present invention has been completed.

  That is, the gist of the present invention is a re-emulsifiable synthetic resin powder composition containing the re-emulsifiable synthetic resin powder (A) and the inorganic fine particles (B), and the inorganic fine particles (B) have an average particle size. The present invention relates to a re-emulsifiable synthetic resin powder composition for polymer cement, characterized by using inorganic fine particles (B1) of 10 μm or less and inorganic fine particles (B2) having an average particle size larger than 10 μm.

  Moreover, in this invention, it is related with the polymer cement mortar which uses the said re-emulsifiable synthetic resin powder composition for polymer cements.

  As described above, the re-emulsifiable synthetic resin powder for polymer cement of the present invention is miscible when mixed with cement (mixing stability, fluidity, adhesive strength, bending strength, compressive strength, low water absorption, low water permeability). Etc.) and also has an effect of being excellent in low-temperature whitening resistance (not causing surface whitening during curing at low temperatures).

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

  The re-emulsifiable synthetic resin powder composition for polymer cement of the present invention contains a re-emulsifiable synthetic resin powder (A) and specific inorganic fine particles (B).

  The re-emulsifiable synthetic resin powder (A) is not particularly limited as long as it is a re-emulsifiable synthetic resin powder that can be used for polymer cement, but preferably a polyvinyl alcohol resin (hereinafter referred to as “PVA resin”). It is a re-emulsifiable synthetic resin powder obtained by drying a synthetic resin emulsion in which the synthetic resin is dispersed and stabilized by [I].

Hereinafter, the case where the re-emulsifiable synthetic resin powder (A) is a re-emulsifiable synthetic resin powder in which the synthetic resin is dispersed and stabilized by the PVA resin [I] will be described.
First, as a premise of the description of the re-emulsifiable synthetic resin powder (A), a synthetic resin emulsion in which the synthetic resin is dispersed and stabilized by the PVA resin [I] will be described.

  As said PVA-type resin [I], the PVA-type resin which has the following specific average saponification degree and average polymerization degree is preferable.

The average saponification degree of the PVA-based resin [I] is preferably 80 to 99.9 mol%, particularly preferably 85 to 99.5 mol%.
If the average degree of saponification is too low, the polymerization does not proceed stably, and even if the polymerization is completed, the storage stability of the emulsion tends to decrease. It is done.

  In the present invention, the average saponification degree can be determined according to the saponification degree calculation method described in JIS K 6726.

Moreover, as average polymerization degree of PVA-type resin [I], it is preferable that it is 50-3,000, Especially preferably, it is 200-2,000, More preferably, it is 200-500.
If the average degree of polymerization is too low, the protective colloid ability at the time of emulsion polymerization will be insufficient and the polymerization will tend not to proceed stably.If it is too high, the reaction system will become unstable due to thickening during the polymerization. Dispersion stability tends to decrease.

  In the present invention, the average degree of polymerization can be determined according to the method for calculating the average degree of polymerization described in JIS K 6726.

  In the present invention, PVA-based resin [I] means PVA itself or, for example, one modified by various modified species, and the degree of modification is usually 20 mol% or less, preferably 15 mol% or less, More preferably, it is 10 mol% or less.

  Examples of the modified PVA resin include an anion modified PVA resin modified with an anionic group including a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group, and a cation modified with a cation group including a quaternary ammonium group. Modified PVA resin, modified PVA resin modified with various functional groups such as acetoacetyl group, diacetone acrylamide group, mercapto group, silanol group, etc., and PVA system having 1,2-diol bond in the side chain Examples thereof include resins.

In this invention, it is preferable that the usage-amount of PVA-type resin [I] is 0.01-20 weight part with respect to 100 weight part of the whole below-mentioned monomer component, Most preferably, it is 0.1-10 weight part. More preferably, it is 0.5 to 7 parts by weight.
If the amount of the PVA resin [I] used is too small, the amount of protective colloid at the time of emulsion polymerization tends to be insufficient and the polymerization stability tends to be poor. If the amount used is too large, the synthetic resin emulsion The viscosity tends to increase and the stability decreases.

  Here, the PVA resin [I] used is usually present in the total amount in the synthetic resin emulsion formed by polymerization. That is, the amount is preferably 0.01 to 20 parts by weight, particularly preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the copolymer. It will be present in the synthetic resin emulsion.

  In the present invention, the PVA resin [I] is usually made into an aqueous solution using an aqueous medium, and this is used in the process of emulsion polymerization. Here, the aqueous medium refers to water or an alcoholic solvent mainly composed of water, preferably water.

The amount (nonvolatile content) of the PVA-based resin [I] in the aqueous solution is not particularly limited, but is preferably 5 to 30% by weight from the viewpoint of easy handling.

  Next, the component materials forming the synthetic resin will be described.

  The synthetic resin emulsion in the present invention is obtained by dispersing and stabilizing a synthetic resin. Examples of the synthetic resin include at least one monomer component such as an acrylic monomer, a styrene monomer, and a vinyl ester monomer as a main component. It is preferable that it is what is polymerized as. In the present invention, the main component means a component that accounts for the majority of the whole, and includes the case where the whole consists of only the main component.

  Examples of the acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) ) Acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate and other aliphatic (meth) acrylates, and phenoxy (meth) acrylate and other aromatic (meth) Acrylate, trifluoroethyl (meth) acrylate, etc., among which aliphatic (meth) acrylates having 1 to 18 carbon atoms in the alkyl group are preferred, and these may be used alone or in combination of two or more. Used.

  Examples of the styrene monomer include styrene and α-methylstyrene. These may be used alone or in combination of two or more.

  Examples of the vinyl ester monomers include linear or branched vinyl esters of monocarboxylic acids having 2 to 12 carbon atoms. Specific examples include vinyl formate, vinyl acetate, vinyl propionate, and valerin. Examples include vinyl acid vinyl, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl versatate, and vinyl 2-ethylhexanoate. These may be used alone or in combination of two or more.

  Further, a functional group-containing monomer or the like may be copolymerized. For example, glycidyl group-containing monomer, allyl group-containing monomer, hydrolyzable silyl group-containing monomer, acetoacetyl group-containing monomer, two vinyl groups in the molecular structure The monomer which has the above, a hydroxyl-group containing monomer, etc. are mentioned.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, glycidyl (meth) allyl ether, 3,4-epoxycyclohexyl (meth) acrylate, and the like. Among these, glycidyl (meth) acrylate is particularly preferable from the viewpoints of little variation in physical properties and improvement of the adhesive strength when wet.

  Examples of the allyl group-containing monomer include monomers having two or more allyl groups such as triallyloxyethylene, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, allyl glycidyl ether, and allyl acetate. Etc. Of these, allyl glycidyl ether is preferred from the viewpoint of adhesive strength when wet.

  Examples of the hydrolyzable silyl group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxy. Examples thereof include propylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane. Of these, vinyltrimethoxysilane is preferred from the viewpoint of adhesive strength when wet.

  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, acetoacetoxy Examples thereof include propyl crotonate and 2-cyanoacetoacetoxyethyl (meth) acrylate. Among these, acetoacetoxyethyl (meth) acrylate is particularly preferable from the viewpoints of little variation in physical properties and improvement of the adhesive strength when wet.

  Examples of the monomer having two or more vinyl groups in the molecular structure include divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, 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, tri Examples include methylolpropane tri (meth) acrylate and allyl (meth) acrylate.

  Examples of the hydroxyl group-containing monomer include (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Of these, 2-hydroxyethyl methacrylate is preferred from the viewpoint of protective colloidal action during emulsion polymerization and improvement of miscibility with cement mortar blends.

  In the synthetic resin emulsion according to the present invention, other components can be further used as necessary in addition to the above-mentioned monomer components. Such other components are not particularly limited as long as the properties as a synthetic resin emulsion are not lowered, and can be appropriately selected according to the purpose. For example, polymerization initiator, polymerization regulator, auxiliary emulsifier , Plasticizers, film-forming aids and the like.

The polymerization initiator is not particularly limited as long as it can be used for ordinary emulsion polymerization. For example, inorganic peroxides such as potassium persulfate, sodium persulfate, ammonium persulfate; organic peroxides, azo series Initiators, 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 may be used alone or in combination of two or more.
Among these, ammonium persulfate and potassium persulfate are preferable from the viewpoint of easy polymerization without adversely affecting the film properties and strength enhancement.

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

  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, normal mercaptan, thiol, and the like. And mercaptans such as glycolic acid, octyl thioglycolate, and thioglycerol. These may be used alone or in combination of two or more. The use of a chain transfer agent is effective in terms of stabilizing the polymerization, but in order to reduce the polymerization degree of the synthetic resin, when used as a cement mortar admixture, the water resistance of the resulting film is reduced. There is a tendency for the physical property variation to increase and the adhesive strength and the like to decrease. For this reason, when using a chain transfer agent, it is desirable to keep the amount used as low as possible.

  Examples of the buffer include sodium acetate, ammonium acetate, dibasic sodium phosphate, sodium citrate and the like. These may be used alone or in combination of two or more.

  Any auxiliary emulsifier can be used as long as it is known to those skilled in the art as being usable for emulsion polymerization. Therefore, auxiliary emulsifiers are, for example, known anionic, cationic and nonionic surfactants, water-soluble polymers having protective colloid ability other than PVA resin [I], and water-soluble oligomers. Can be selected as appropriate.

  Examples of the surfactant include anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, and nonionic surfactants such as those having a pluronic structure and those having a polyoxyethylene structure. Agent. Moreover, the reactive surfactant which has a radically polymerizable unsaturated bond in a structure can also be used as a surfactant. These may be used alone or in combination of two or more.

  The use of the surfactant has an effect of facilitating the emulsion polymerization smoothly, making it easy to control (effect as an emulsifier), and suppressing the generation of coarse particles and block-like substances generated during the polymerization. However, if many of these surfactants are used as emulsifiers, the graft rate tends to decrease. For this reason, when using a surfactant, it is desirable that the amount used is auxiliary to the PVA resin [I], that is, as small as possible.

  Examples of the water-soluble polymer having protective colloid ability other than the PVA resin [I] include PVA resins other than the PVA resin [I], hydroxyethyl cellulose, polyvinyl pyrrolidone, methyl cellulose, and the like. These may be used alone or in combination of two or more. These are effective in that the viscosity is changed by increasing the viscosity of the emulsion or changing the particle size of the emulsion. However, since the water resistance of the film may be lowered depending on the amount used, it is desirable to use a small amount when used.

  As the water-soluble oligomer, for example, a polymerization degree having a hydrophilic group such as a sulfonic acid group, a carboxyl group, a hydroxyl group, and an alkylene glycol group is preferable, and a polymer or copolymer of about 10 to 500 is preferable. . Specific examples of the water-soluble oligomer include, for example, amide copolymers such as 2-methacrylamide-2-methylpropanesulfonic acid copolymer, sodium methacrylate-4-styrenesulfonate copolymer, styrene / maleic acid copolymer. Examples include polymers, melamine sulfonic acid formaldehyde condensates, poly (meth) acrylates, and the like. Furthermore, specific examples include a monomer having a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkylene glycol group, and a water-soluble oligomer obtained by previously copolymerizing a radical polymerizable reactive emulsifier alone or with another monomer. It is done. These may be used alone or in combination of two or more.

  Among these, 2-methacrylamide-2-methylpropane sulfonic acid copolymer and sodium methacrylate-4-styrene sulfonate copolymer are preferable from the viewpoint of mixing stability with pigments and fillers such as calcium carbonate. As the water-soluble oligomer, those previously polymerized before starting the emulsion polymerization may be used, or commercially available products may be used.

  As the plasticizer, an adipate plasticizer, a phthalic acid plasticizer, a phosphoric acid plasticizer, or the like can be used. A film-forming aid having a boiling point of 260 ° C. or higher 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.

  Next, a method for producing the synthetic resin emulsion used in the present invention will be described.

  The synthetic resin emulsion used in the present invention can be produced, for example, by emulsion polymerization of the above monomer components using PVA resin [I] as a protective colloid agent. In this polymerization process, a synthetic resin emulsion is produced in which an acrylic resin dispersed and stabilized by PVA resin [I], which is a protective colloid agent, is used as a dispersoid.

  Usually, emulsion polymerization is carried out using the above-described other components such as a polymerization initiator, a polymerization regulator, and an auxiliary emulsifier as needed in addition to the PVA resin [I] and the monomer component. The polymerization reaction conditions are not particularly limited, and can be appropriately selected according to the type and purpose of the monomer.

  The emulsion polymerization method is not particularly limited. For example, a monomer dropping emulsion polymerization method in which water and PVA-based resin [I] are charged into a reaction can and the temperature is raised and a monomer component and a polymerization initiator are dropped; and The monomer to be dropped is dispersed and emulsified in advance with PVA resin [I] and water, and then dropped into the emulsion monomer dropping type emulsion polymerization method. The dripping method is convenient.

  The emulsion polymerization process will be described more specifically as follows.

  First, water, PVA-based resin [I], and an auxiliary emulsifier as necessary are charged into a reaction can, and after raising the temperature (usually 65 to 90 ° C.), a part of the monomer component and the polymerization initiator are added to the reaction can. To carry out the initial polymerization. Next, the remaining 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 synthetic resin emulsion can be taken out.

  In the present invention, the synthetic resin emulsion obtained by emulsion polymerization is typically uniform milky white, and the average particle size of the synthetic resin in the synthetic resin emulsion is preferably 0.2 to 2 μm, More preferably, it is 0.3-1.5 micrometers.

  Here, the average particle diameter can be measured by a conventional method, for example, a laser analysis / scattering particle size distribution measuring apparatus “LA-950S2” (manufactured by Horiba, Ltd.).

Moreover, when the glass transition temperature of the synthetic resin in the synthetic resin emulsion is −20 to + 30 ° C., when used as a cement mortar admixture, there are few physical property variations and, in addition, the adhesive strength is improved. In particular, it is preferably −15 to + 20 ° C.
If the glass transition temperature is too low, the adhesive strength tends to decrease, and if it is too high, a plasticizer such as dibutyl phthalate is added to reduce the film forming temperature of the synthetic resin emulsion. There exists a tendency for adhesive strength etc. to fall.

  The glass transition temperature of the synthetic resin in the present invention is a value calculated by the Fox equation based on the monomer component. In addition, when using together a functional group containing monomer, it may be calculated by the formula of Fox based on the main monomer component except this functional group containing monomer.

  Furthermore, in the present invention, it is determined that at least a part of the PVA-based resin [I] is grafted to the synthetic resin, and the measured value in the measurement of storage stability and adhesive strength of the resulting synthetic resin emulsion itself before drying. This is preferable from the viewpoint of reducing the variation in the number of the dots.

  When the PVA resin [I] is grafted to the synthetic resin, the value (W) represented by the following formula (1) is preferably 50% by weight or more, more preferably 65% by weight or more, More preferably, it is 70 weight% or more. In addition, as an upper limit, it is 95 weight% normally, Preferably it is 85 weight%, More preferably, it is 80 weight%. This value is a measure of the degree of grafting, and if this value is too low, the degree of grafting is low, the protective colloid action during emulsion polymerization is lowered, the polymerization stability is lowered, There is a tendency for miscibility with fillers to decrease.

The value (W) of equation (1) is calculated as follows.
That is, a target emulsion or the like is dried at room temperature to prepare a film, and the film is extracted in boiling water and acetone for 8 hours, respectively, to remove ungrafted resin and the like. In this case, the absolute dry weight of the film before extraction is w ₁ (g), and the absolute dry weight of the film after extraction is w ₂ (g).

W (% by weight) = (w ₂ ) / (w ₁ ) × 100 (1)

  As a method for adjusting the value (W) of the above formula (1) to 50% by weight or more, the emulsion polymerization temperature is made slightly higher than before, or a very small amount of reducing agent (persulfate used as a polymerization catalyst) For example, acidic sodium sulfite is used in combination.

  In this invention, you may further add various additives to the synthetic resin emulsion after emulsion polymerization as needed. Examples of such additives include organic pigments, inorganic pigments, water-soluble additives, pH adjusters, preservatives, and antioxidants.

  Thus, although the synthetic resin emulsion used by this invention is obtained, when using it, it is preferable to adjust to 40 to 60 weight% normally as a non volatile matter.

  The re-emulsifiable synthetic resin powder (A) according to the present invention is obtained by drying the obtained synthetic resin emulsion. Hereinafter, the production of the re-emulsifiable synthetic resin powder (A) will be described.

  The method for drying the synthetic resin emulsion 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, 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 nonvolatile content of the synthetic resin emulsion, the viscosity, the flow rate, and the like. The temperature for spray drying is usually preferably from 80 to 180 ° C, more preferably from 120 to 160 ° C. If the drying temperature is too low, it takes time to dry, which may cause problems in production. If it is too high, the resin itself tends to be altered by heat.

  The spray drying process will be described with further specific examples. First, the non-volatile 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 addition, in this invention, the blocking prevention effect of a powder can also be acquired by adding the below-mentioned inorganic fine particle (B) (especially inorganic fine particle (B1)).

  Moreover, in order to improve the re-emulsification property to water of the re-emulsifiable synthetic resin powder (A), a water-soluble additive can be blended. Usually, the water-soluble additive is added to the synthetic resin emulsion before drying. This addition amount is 2 to 50 parts with respect to 100 parts of the non-volatile content of the synthetic resin emulsion before drying. If the amount added is too small, there is a tendency that the re-emulsification property to water cannot be sufficiently improved. If the amount is too large, the water re-emulsification property to water is greatly improved, but the water resistance of the film is lowered and expected. The physical properties that are used may not be exhibited.

  Examples of the water-soluble additive include PVA resins, hydroxyethyl celluloses, methyl celluloses, polyvinyl pyrrolidone, starches, dextrins, water-soluble alkyd resins, water-soluble amino resins, water-soluble acrylic resins, and water-soluble polycarboxylic acids. Examples thereof include water-soluble resins such as acid resins and water-soluble polyamide resins. These may be used alone or in combination of two or more. Among these, PVA-based resins are preferable.

  As said PVA-type resin, polyvinyl alcohol with an average saponification degree of 85 mol% or more is desirable, and it is more preferable that it is 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 of the film tends to be remarkably lowered. If it is too large, the water resistance is improved, but the re-emulsification property to water tends to be lowered.

  Moreover, this average degree of polymerization is usually preferably 50 to 3000, more preferably 200 to 2000, and further preferably 300 to 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.

  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.

  Thus, the re-emulsifiable synthetic resin powder (A) of the present invention is obtained.

  The re-emulsifiable synthetic resin powder composition of the present invention comprises the re-emulsifiable synthetic resin powder (A) and inorganic fine particles (B).

The inorganic fine particles (B) of the present invention are essentially composed of inorganic fine particles having different average particle sizes, that is, inorganic fine particles (B1) having an average particle size of 10 μm or less and inorganic fine particles (B2) having an average particle size of 10 μm or less. It is contained as
As long as the above (B1) and (B2) each include at least one kind of inorganic fine particles having a corresponding average particle diameter, one or both of them may contain two or more kinds of inorganic fine particles.

  In addition, the said average particle diameter is measured using the laser analysis / scattering type particle size distribution measuring apparatus "LA-950S2 dry-type measurement unit equipment" (made by Horiba, Ltd.).

  As the inorganic fine particles (B1), those generally blended as reblockable synthetic resin powders as an antiblocking agent may be used, and in the present invention, the antiblocking performance is mainly exhibited in the composition. It is.

The average particle diameter of the inorganic fine particles (B1) may be an average particle diameter of 10 μm or less, preferably 0.1 to 10 μm, particularly preferably 1 to 9 μm.
When the average particle size is too large, the fluidity, denseness, bending strength, and compressive strength of the mortar are likely to be lowered.
In addition, when this average particle diameter is too small, there exists a tendency for on-site workability | operativity by anti-blocking performance and dust scattering to fall remarkably.
Further, as the inorganic fine particles (B1), particles having a particle diameter of 0.0001 μm or less are preferably 20% or less, and particles having a particle diameter of 10 μm or more are preferably 5% or less.

Examples of the inorganic fine particles (B1) include colloidal silica gel, calcined silica, precipitated silica, microsilica, charcoal cal, talc, clay, anhydrous silicic acid, aluminum silicate, white carbon, alumina white, barium sulfate, kaolin, titanium oxide, Examples include hydrated alumina, bentonite, calcium sulfoaluminate, calcite, chalk, quartz powder, dolomite, gypsum, mica, diatomaceous earth, partially ground aluminum silicate, magnesium carbonate, magnesium hydrosilicate, and the like.
Among these, talc, clay, silicic anhydride, kaolin, barium sulfate, and dolomite are preferable, and talc, clay, silicic anhydride, and dolomite are particularly preferable.

The content of the inorganic fine particles (B1) is preferably 5 to 30 parts by weight, particularly preferably 5 to 20 parts by weight, more preferably 100 parts by weight of the re-emulsifiable synthetic resin powder (A). Is 10 to 20 parts by weight.
If the content of the inorganic fine particles (B1) is too large, the flowability of the mortar tends to decrease, or the adhesive strength, bending strength, or compressive strength tends to decrease. Sometimes blocking tends to occur, and adhesion to manufacturing equipment tends to occur during spray drying.

  The inorganic fine particles (B2) generally have a large average particle size as inorganic fine particles blended as an antiblocking agent in the re-emulsifiable synthetic resin powder. In the present invention, the inorganic fine particles (B2) are mainly inorganic in the composition. The migration preventing performance of the fine particles (B1) is exhibited.

The average particle size of the inorganic fine particles (B2) may be an average particle size larger than 10 μm, preferably 10 to 250 μm, particularly preferably 30 to 200 μm, and further preferably 30 to 150 μm.
When the average particle size is too small, the migration prevention performance is lowered, and the whitening prevention performance of the mortar surface is difficult to obtain.
If the average particle size is too large, it tends to be a re-emulsifiable powder with a low apparent density, or a mortar with poor fluidity may be obtained.
As the inorganic fine particles (B2), particles having a particle diameter of 0.1 μm or less are preferably 10% or less, and particles having a particle diameter of 500 μm or more are preferably 10% or less.

  As the kind of the inorganic fine particles (B2), those similar to the inorganic fine particles (B2) may be used, but silica is preferable, and amorphous silica is particularly preferable.

  Commercially available products of such inorganic fine particles (B2) include amorphous silica (Evonik Degussa, trade name “SIPRNAT 22”), amorphous silica (Evonik Degussa, trade name “SIPRNAT 30”), Amorphous silica (made by Evonik Degussa, trade name “SIPRNAT 50”), synthetic amorphous silica (made by Tokuyama, trade name “Tokuseal PR”), silica with initial solution (made by Wacker, trade name “ BS-Powder A ")).

The content of the inorganic fine particles (B2) is preferably 0.5 to 10 parts by weight, particularly preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the re-emulsifiable synthetic resin powder (A). Parts, more preferably 1 to 5 parts by weight.
If the content of the inorganic fine particles (B2) is too large, the flowability of the mortar tends to decrease, or the adhesive strength, bending strength, or compressive strength tends to decrease. There exists a tendency for antiblocking property to fall.

The blending ratio (weight ratio) of the inorganic fine particles (B1) and (B2) is preferably (B1) :( B2) = 100: 1 to 100: 30, particularly preferably (B1) :( B2 ) = 100: 10 to 100: 30, more preferably (B1) :( B2) = 100: 10 to 100: 15.
If the blending ratio of the inorganic fine particles (B1) to the inorganic fine particles (B2) is too large, the whitening prevention performance on the mortar surface in winter tends to be lowered, and if it is too small, mortar having poor fluidity tends to be formed.

The content of the inorganic fine particles (B) (the total amount of (B1) and (B2)) is preferably 1 to 50 parts by weight, particularly 100 parts by weight of the re-emulsifiable synthetic resin powder (A). Preferably it is 5-40 weight part, More preferably, it is 7-30 weight part.
If the amount of the inorganic fine particles (B) is too large, the flowability of the mortar tends to decrease, or the adhesive strength, bending strength, or compressive strength tends to decrease. If the amount is too small, the anti-blocking property tends to decrease. is there.

  By containing the re-emulsifiable synthetic resin powder (A) and the inorganic fine particles (B), the re-emulsifiable synthetic resin powder composition for polymer cement of the present invention is obtained.

As a method for producing a re-emulsifiable synthetic resin powder composition for polymer cement,
(1) A method in which inorganic fine particles (B) are premixed in a synthetic resin emulsion and then spray-dried,
(2) A method of spraying inorganic fine particles (B) from a nozzle different from that of the synthetic resin emulsion into a powder during spray drying of the synthetic resin emulsion,
(3) A method of mixing inorganic fine particles (B) with a re-emulsifiable synthetic resin powder (A) using a Nauter mixer or the like,
Among them, among these, (2) and (3) are combined, and first the total amount (or part) of the inorganic fine particles (B1) is added by the method (2), and then by the method (3) The method of mixing the inorganic fine particles (B2) (and the rest of the inorganic fine particles (B1)) is preferable in that the effect of adding the inorganic fine particles (B2) can be sufficiently obtained.

  In the re-emulsifiable synthetic resin powder composition for polymer cement of the present invention, in addition to the above-mentioned re-emulsifiable synthetic resin powder (A) and inorganic fine particles (B), a water reducing agent, a dispersant, a mortar fluidization accelerator, You may contain a liquid agent, antioxidant, a rust preventive agent, etc.

  The re-emulsifiable synthetic resin powder composition for polymer cement thus obtained can be used as a polymer cement composition by blending with cement, and further used as mortar or concrete by blending water, sand or gravel. be able to.

  Examples of the cement include ordinary Portland cement, alumina cement, early-strength Portland cement, ultra-early strong Portland cement, medium heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, blast furnace cement, fly ash cement, silica cement, and the like. Among them, Portland cement is preferable from the viewpoint of workability.

  The blending amount of the cement is preferably 3 to 500 parts by weight, more preferably 30 to 350 parts by weight with respect to 100 parts by weight of the re-emulsifiable synthetic resin powder (A).

  The blending amount of water when used as mortar or concrete is preferably 50% by weight or less, more preferably 30% by weight or less, based on the total amount of the polymer cement composition.

  The amount of sand and gravel used as mortar or concrete is preferably 30 to 300% by weight, more preferably 50 to 150% by weight, based on the total amount of the polymer cement composition. .

  The polymer cement composition may include a cement water reducing agent or fluidizing agent (for example, lignin-based, naphthalene-based, melamine-based, carboxylic acid-based, etc.), shrinkage reducing agent (for example, glycol ether-based). , Polyether, etc.), anti-chilling agents (eg, calcium chloride, etc.), waterproofing agents (eg, stearic acid, etc.), rust inhibitors (eg, phosphates, etc.), viscosity modifiers (eg, methylcellulose, hydroxyethylcellulose, Polyvinyl alcohol, etc.), dispersants (eg, polycarboxylic acid-based, inorganic phosphorus-based, etc.), antifoaming agents (eg, silicon-based, mineral oil-based), preservatives, reinforcing agents (eg, steel fibers, glass fibers, synthetics) Fiber, carbon fiber, etc.) may be used alone or in combination of two or more.

  In addition to the above components, various aggregates such as pozzolanic materials such as calcium carbonate, kaolin, clay, diatomaceous earth, silica fume, fly ash, blast furnace slag, and natural and artificial lightweight aggregates may be blended.

  The polymer cement composition preferably has a viscosity of 5000 mPa · s or less, particularly preferably 50 to 4500 mPa · s, more preferably 100, as measured with a B-type viscometer at 23 ° C. and a rotation speed of 10 rpm. ˜4000 mPa · s. When the viscosity is too low, the inorganic powder tends to settle and the uniformity of the coating film tends to be impaired. When the viscosity is too high, the workability during coating tends to be reduced.

  In addition, when using a polymer cement composition as a polymer cement mortar, as in general mortar, an essential component and an optional component are added, and after adding an appropriate amount of water, a kneader or the like is added. It can be prepared by using and kneading.

  The polymer cement obtained as described above exhibits good fluidity and workability when mixed with cement mortar, has excellent adhesion to the old mortar surface and resin coated surface, and has little variation in physical properties. In addition, it has excellent effects such as improved adhesive strength. These are useful as admixtures for cement mortar, for repair mortars, for base preparation coating materials, self-leveling materials, tile adhesive mortars, mortar sealers / primers, mortar curing agents, and gypsum-based materials. Furthermore, it is also useful for civil engineering and building materials, glass fiber sizing agents, flame retardants and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

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

<Production Example of Synthetic Resin Emulsion Powder (A)>
[Production of re-emulsifiable synthetic resin powder (A-1)]
In a 2 L stainless steel reactor equipped with a mechanical stirrer and a reflux condenser, 600 parts of deionized water and PVA (viscosity at 20 ° C. of a 4% concentration solution; 5 mPas, average polymerization degree 500, average) Saponification degree 88 mol%) 63.7 parts, sodium lauryl sulfate (Kao (product name, “Emar 10 powder”) 0.6 part, ethylene oxide / propylene oxide copolymer (product made by Clariant Japan), product Name "Genapol PF 20" 1.8 parts), antifoaming agent (manufactured by San Nopco Co., Ltd., trade name "Nopco 8034") 0.4 parts, sodium acetate 1.4 parts mixture, reactor internal temperature Is heated to 70 ° C. (polymerization solution) Further, 318 parts of vinyl acetate, vinyl acetate vinyl ester (manufactured by Hexion Specialty Chemicals Co., Ltd., trade name “V”) oVa10 ") 318 parts of monomer mixture and 71 parts of n-butyl acrylate and 2,2'-azobis (2-methylpropionamidine) hydrochloride (trade name" V-50 "manufactured by Wako Pure Chemical Industries, Ltd.) An initiator solution in which 1.2 parts are dissolved in 27.0 parts deionized water is prepared.
72 parts of the monomer mixture are added to the polymerization solution heated to an internal temperature of 70 ° C. After the internal temperature has again reached 70 ° C., 5.6 parts of initiator solution are added and an initial polymerization is carried out for 15 minutes. The monomer mixture and 19.8 parts of the initiator solution in parallel are metered in at 70 ° C. over 3 hours. Add remaining initiator solution after metering. The mixture is heated to 80 ° C. and reacted at that temperature for 1 hour. After 1 hour of reaction at 80 ° C., the mixture was cooled to 50 ° C., and 1 part of t-butyl hydroperoxide (manufactured by NOF Corporation, trade name “Perbutyl H69”) was dissolved in 6 parts of deionized water. A solution and a solution of 0.7 part sodium bisulfite in 15 parts deionized water are metered in over 15 minutes.
Thereafter, the mixture was cooled, and 38 parts of PVA (viscosity of a 4% concentration solution at 20 ° C .; 5 mPas, average degree of polymerization 500, average degree of saponification 88.0 mol%) was dissolved in 158.0 parts of deionized water. An aqueous solution is added to obtain an emulsion having a solid content of 50%.
In the presence of 10 parts by weight of inorganic fine particles (B1) of the type shown in Table 1 below, 100 parts by weight of the emulsion whose water content was adjusted to 40% by adding water was heated at 140 ° C. using a nozzle type spray dryer as the heat source. It was spray-dried under warm air to obtain a re-emulsifiable synthetic resin powder (A-1).

[Production of re-emulsifiable synthetic resin powder (A-2)]
In a separable flask equipped with a mechanical stirrer and a reflux condenser, 135 parts by weight of deionized water and PVA having a 1,2-diol bond in the side chain as a protective colloid (average polymerization degree 300, average saponification degree 98) .5 mol% or more, content of 1,2 diol bond in side chain: 8 mol% / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 10 parts by weight, heat reaction can to 80 ° C. to side chain PVA having a 1,2-diol bond was dissolved.
Next, the temperature of the reaction vessel is maintained at 70 ° C., and 5.5 parts by weight of butyl acrylate and 4.5 parts by weight of methyl methacrylate are added as monomer components, and ammonium perpersulfate is used as a polymerization initiator. The initial polymerization reaction was performed for 1 hour. Next, 49.5 parts by weight of butyl acrylate and 40.5 parts by weight of methyl methacrylate are metered into the reaction vessel over 4 hours as the remaining monomer components, and the dropping polymerization reaction is allowed to proceed while further adding ammonium persulfate as a polymerization initiator. It was. After completion of the dropping polymerization, the mixture was aged for 1 hour, and then a 20% by weight aqueous solution of partially saponified PVA having an average polymerization degree of 500 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “GOHSENOL GL05”) was sufficiently added. Stir. This gave an emulsion with a solids content of about 40%. In the presence of 10 parts by weight of inorganic fine particles (B1-1), 100 parts by weight of an emulsion having a non-volatile content adjusted to 40% was spray-dried under hot air at 140 ° C. using a nozzle-type spray dryer as a heat source. A re-emulsifiable synthetic resin powder (A-2) was obtained.

[Production of re-emulsifiable synthetic resin powder (A-3)]
A pressure autoclave is charged with 135 parts by weight of deionized water, 92 parts by weight of an aqueous solution of PVA having a saponification degree of 88 mol% and a viscosity of 4 mPas by Heppler, and 227 parts of vinyl acetate. The pH is adjusted to about 4.0 with formic acid, then 0.5 part of 1% solids ammonium iron sulfate is added. The autoclave is heated to 55 ° C. and charged with ethylene to a pressure of 8 bar. The polymerization reaction is initiated by adding 3% t-butyl hydroperoxide solution and 5% ascorbic acid solution. The reaction temperature is controlled at 120 ° C. Increasing the temperature increases the ethylene pressure, which is 38 bar at 85 ° C and 55 bar at 120 ° C. The addition rate when reaching 100 ° C. is 35%. Between 30 minutes and 60 minutes after the start of the reaction, 35 parts by weight of an aqueous solution of PVA having 57 parts by weight of vinyl acetate, a saponification degree of 88 mol% and a viscosity of 4 mPas by Heppler is metered in. After completion of the reaction, the autoclave is cooled and unreacted ethylene is discharged. Thereafter, the solid content concentration is adjusted to 55% by weight. 26 parts by weight of a 20% by weight aqueous solution of partially saponified polyvinyl alcohol having an average polymerization degree of 500 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “GOHSENOL GL05”) was added to 100 parts of this 55% by weight emulsion. An emulsion with a non-volatile content of 48% is obtained. The nonvolatile content is adjusted to 40%, and 100 parts by weight of the emulsion is spray-dried under a hot air of 140 ° C. using a nozzle-type spray dryer as a heat source in the presence of 10 parts by weight of inorganic fine particles (B1-1). To obtain a re-emulsifiable synthetic resin powder (A-3).

<Inorganic fine particles (B)>
The following were prepared as inorganic fine particles (B1) having an average particle diameter of 10 μm or less.
-(B1-1) Talc dolomide (Palten taler Minerals GmbH & Co KG: trade name “SE-Super”: average particle size 5-8 μm)
(B1-2) Reaction product of dichlorodimethylsilane and silica (Evonik Degussa Japan Co., Ltd .: trade name “Sipernat D17: average particle size 5.5 to 5.6 μm)
In addition, the following were prepared as inorganic fine particles (B2) having an average particle diameter of 10 μm or more.
-(B2-1) amorphous silica (Evonik Degussa Japan Co., Ltd. product name: "Sipernat 50": average particle size 59-62 μm)
(B2-2) Amorphous silica (Evonik Degussa Japan Co., Ltd., product name: “Sipernat 22”: average particle size 100 μm)
(B2-3) Silica and organosilane composite (Asahi Kasei Wacker Silicone Co., Ltd. product name: “BS-Powder A”: average particle size 115 μm)
(B2-4) Synthetic amorphous silica (manufactured by Tokuyama Co., Ltd .: trade name “Tokuseal PR”: average particle diameter of 168 to 170 μm)

[Examples 1 to 9, Comparative Examples 1 to 4]
The re-emulsifiable synthetic resin powder obtained above is introduced into a Nauter mixer, added while dividing the remaining amount of the anti-blocking agent (B2) and the anti-blocking agent (B1), and stirred for 15 minutes after adding the total amount. A desired re-emulsifiable synthetic resin powder was obtained.

  About the obtained re-emulsifiable synthetic resin powder composition, blocking resistance was evaluated as follows.

<Blocking resistance>
A stainless steel cylindrical container A having an inner diameter of 45 mm and a height of 100 mm is placed on a glass plate, 50 g of a re-emulsifiable synthetic resin powder composition is placed, and then the outer diameter is adjusted to a total weight of 500 g and the height is 80 mm. A cylindrical container B with a bottom made of stainless steel is placed in the container A. This is placed horizontally in a thermo-hygrostat adjusted to a temperature of 40 ° C. and a humidity of 60% and left to stand for 16 hours. Next, the product was taken out from the dryer, allowed to cool at room temperature for 2 hours, and then the containers A and B were gently wiped off to examine the solid state of the re-emulsifiable synthetic resin powder composition. The evaluation criteria are as follows, and the results are shown in Table 1 below.
(Evaluation criteria)
A: The re-emulsifiable synthetic resin powder composition does not remain in the cylinder and is not blocked when the cylinder is extracted. Alternatively, the re-emulsifiable synthetic resin powder composition does not remain in the cylinder when the cylinder is extracted, but there are aggregates in the re-emulsifiable synthetic resin powder composition that are easily broken by hand.
B: The re-emulsifiable synthetic resin powder composition remains in the cylinder when the cylinder is extracted, but when the re-emulsifiable synthetic resin powder composition is taken out of the cylinder, it collapses into a powder.
C: When the cylinder is extracted, the re-emulsifiable synthetic resin powder composition remains in the cylinder, and the re-emulsifiable synthetic resin powder composition taken out of the cylinder has a cylindrical shape. When the upper part of the synthetic resin powder composition is grasped and lifted, it collapses.
D: When the cylinder is extracted, the re-emulsifiable synthetic resin powder composition remains in the cylinder, and the solidified re-emulsifiable synthetic resin powder composition extracted from the cylinder cannot be crushed by hand. Alternatively, when the cylinder is removed, the re-emulsifiable synthetic resin powder composition remains in the cylinder, and the solidified re-emulsifiable synthetic resin powder composition taken out of the cylinder is crushed by hand and becomes a powder. Some things cannot be crushed.

  Moreover, cement mortar was produced using the re-emulsifiable synthetic resin powder composition obtained above, and the following evaluation was performed.

<Production of cement mortar>
Cement mortar was prepared by mixing 50 g of the above re-emulsifiable synthetic resin powder composition, 500 g of ordinary Portland cement, 1500 g of Toyoura cinnabar, and 340 g of kneaded water and stirring for 3 minutes with a Hobart mixer.

<Low temperature whitening resistance>
The cement mortar was kneaded in an atmosphere of 5 ° C., molded with a mold for bending / compression test specified in JIS A 1172, and the state of the mortar surface was observed after curing for 1 month in an atmosphere of 5 ° C.
The evaluation criteria are as follows, and the results are shown in Table 1.
(Evaluation criteria)
A: No whitened portion is observed on the mortar surface.
B: A slight whitening portion is observed on the mortar surface.
C: A clear whitened portion is observed on the mortar surface.
D: A whitened portion is observed on the entire surface of the mortar.

<Cement mortar fluidity>
About the said cement mortar, the cement mortar fluidity | liquidity test was done according to JISR5201.
The fluidity of this cement mortar is determined by filling the cement mortar into a flow cone with a bottom diameter of 100 mm installed on a flow table, pulling out the flow cone, and giving a 12 mm drop impact 15 times to give the spread diameter of the mortar cement. Was measured. The evaluation criteria are as follows, and the results are shown in Table 1.
(Evaluation)
A ... 170 mm or more B ... 150 mm or more and less than 170 mm C ... 100 mm or more and less than 150 mm D ... less than 100 mm

<Cement mortar bending strength>
About the said cement mortar, the cement mortar bending strength was measured according to JISA1172. Moreover, the evaluation standard of the bending strength of cement mortar followed the standard of JIS A6203.
The bending strength test of this cement mortar was conducted after adjusting the cement mortar under an atmosphere defined in JIS A 1172, filling it into a mold having a cross section of 40 mm and a length of 160 mm, and passing through a curing time defined in JIS A 6203. The bending strength was measured.
The evaluation criteria are as follows, and the results are shown in Table 1.
(Evaluation)
A ... 10Nmm ² or more
B ... 8 Nmm ² or more and less than 10 Nmm ²
C: 5 Nmm ² or more and less than 8 Nmm ²
D ... less than 5 Nmm ²

<Cement mortar compressive strength>
About the said cement mortar, the cement mortar compressive strength was measured according to JISA1172. Moreover, the evaluation standard of the compressive strength of cement mortar followed the standard of JIS A6203.
This cement mortar compressive strength test was conducted after adjusting the cement mortar in an atmosphere defined in JIS A 1172, filling it in a mold having a cross section of 40 mm and a length of 160 mm, and passing a curing time defined in JIS A 6203. The bending strength was measured.
The evaluation criteria are as follows, and the results are shown in Table 1.
(Evaluation)
A ... 30Nmm ² or more
B ... 24Nmm ² or more and less than 30Nmm ²
C: 15 Nmm ² or more and less than 24 Nmm ²
D: Less than 15 Nmm ²

  The re-emulsifiable synthetic resin powder compositions for polymer cements of Examples 1 to 9 contain inorganic fine particles (B1) and (B2), and are miscible with the cement (fluidity, bending strength, compression). It is excellent in strength) and does not cause whitening even when polymer cement mortar is applied at low temperatures.

  In contrast, the re-emulsifiable synthetic resin powder compositions for polymer cements of Comparative Examples 1 and 3 that do not contain inorganic fine particles (B2) are inferior in low-temperature whitening resistance and do not contain inorganic fine particles (B1). It can be seen that the re-emulsifiable synthetic resin powder compositions for polymer cements of Examples 2 and 4 are poor in fluidity of the polymer cement mortar.

  The re-emulsifiable synthetic resin powder composition for polymer cement of the present invention has a re-emulsifiable synthetic resin powder that is miscible when mixed with cement (mixing stability, fluidity, adhesive strength, bending strength, compressive strength, low water absorption) , Low water permeability, etc., and also has an excellent effect on low-temperature whitening resistance. For cement mortar use, it is used for repair mortar, for base preparation, self-leveling material, tile adhesive mortar, mortar sealer primer It is very useful as a modifier for mortar curing agents and gypsum-based materials.

Claims (7)

  A re-emulsifiable synthetic resin powder composition comprising re-emulsifiable synthetic resin powder (A) and inorganic fine particles (B), and inorganic fine particles (B1) having an average particle size of 10 μm or less as inorganic fine particles (B) And a re-emulsifiable synthetic resin powder composition for polymer cement, characterized by using inorganic fine particles (B2) having an average particle size of more than 10 μm.   The re-emulsifiable synthetic resin powder (A) is a re-emulsifiable synthetic resin powder obtained by drying a synthetic resin emulsion in which a synthetic resin is dispersed and stabilized by a polyvinyl alcohol resin [I]. 2. The re-emulsifiable synthetic resin powder composition for polymer cement according to 1.   The re-emulsifiable synthetic resin powder composition for polymer cement according to claim 1 or 2, wherein the inorganic fine particles (B1) have an average particle size of 0.1 to 10 µm.   The re-emulsifiable synthetic resin powder composition for polymer cement according to any one of claims 1 to 3, wherein the inorganic fine particles (B2) have an average particle size of 30 to 200 µm.   The re-emulsifiable synthetic resin powder composition for polymer cement according to any one of claims 1 to 4, wherein the inorganic fine particles (B2) are amorphous synthetic silica.   6. The blending ratio (weight ratio) of the inorganic fine particles (B1) and (B2) is (B1) :( B2) = 100: 1 to 100: 30. Any re-emulsifiable synthetic resin powder composition for polymer cements.   A polymer cement mortar using the re-emulsifiable synthetic resin powder composition for polymer cement according to any one of claims 1 to 6.