JP4071182B2 - Admixture or joint material for synthetic resin powder and hydraulic material - Google Patents

Description

  The present invention relates to a synthetic resin powder, and more specifically, one or two or more unsaturated monomers selected from ethylenically unsaturated monomers and diene monomers using a vinyl alcohol polymer as a dispersant. Obtained by spray-drying a composition in which a vinyl alcohol polymer (B) having a 1,2-glycol bond of 1.9 mol% or more is blended with an emulsion (A) having a polymer having a unit as a dispersoid It relates to synthetic resin powder.

The synthetic resin powder is produced by spray-drying a synthetic resin emulsion, and is superior in terms of handling and transportation because it is a powder compared to the synthetic resin emulsion. In addition, in use, it is easily redispersed in water by adding water and stirring, and therefore, it is used for a wide range of applications such as cement, an admixture to cement mortar, an adhesive, and a binder for paint. Among them, the admixture for mortar is widely used because it is a powder and can be premixed and can be used in various commercial forms. However, in the conventional synthetic resin emulsion, when it is spray-dried as it is, the dispersoid easily melts and does not re-disperse in water, so a large amount of polyvinyl alcohol is added afterwards, and further as an anti-blocking agent. At present, it is necessary to use a large amount of inorganic powder such as silicic anhydride. As the post-added polyvinyl alcohol (PVA), it is necessary to re-emulsify after use after pulverization, and thus, conventional partially saponified PVA has been widely used (Patent Document 1). However, the redispersibility of the obtained powder is not necessarily sufficiently excellent, and since it is powdered by mixing a large amount of partially saponified PVA, the water resistance of the emulsion obtained by redispersing the obtained powder is There was a problem that the property was inferior to that before pulverization. Also known is a synthetic resin powder obtained by spray-drying an aqueous emulsion containing a vinyl alcohol polymer having a 1,2-glycol bond of 1.7 mol% or more as a dispersant (Patent Document 2). As will be apparent from Comparative Example 6 described later, the synthetic resin powder obtained by this method has good redispersibility, but is still not sufficiently excellent, and is a hydraulic substance such as cement or cement mortar. When used as an admixture or jointing material, the physical properties such as bending strength are good, but it cannot be said that it is still sufficiently excellent.
JP-A-11-263849 (Claims 1, [0011], [0012]) JP 2001-342260 A (Claim 1, [0010])

  The object of the present invention is to solve the above-mentioned problems, excellent in redispersibility, further excellent in water resistance, and also excellent in film-forming properties when redispersed, standing stability at low temperature, etc. It is an object of the present invention to provide a synthetic resin powder that exhibits excellent performance when used with an admixture or joint material for hydraulic substances such as cement or cement mortar.

  As a result of intensive investigations in view of the above circumstances, the present inventors have found that one or two or more kinds of solvents selected from ethylenically unsaturated monomers and diene monomers using a vinyl alcohol polymer as a dispersant. Spray-drying a composition in which a vinyl alcohol polymer (B) having a 1,2-glycol bond of 1.9 mol% or more is blended with an emulsion (A) having a polymer having a saturated monomer unit as a dispersoid The synthetic resin powder obtained in this way has been found to solve the above problems, and the present invention has been completed.

  According to the present invention, it is possible to obtain a synthetic resin powder having excellent redispersibility, further excellent water resistance, and excellent film forming property when redispersed and excellent storage stability at low temperatures. Also, by using this synthetic resin powder, it is excellent in dispersibility in hydraulic materials such as cement or cement mortar, and can further impart excellent strength to the obtained hydraulic material. Is obtained. Further, by using the synthetic resin powder of the present invention, a joining material for a hydraulic substance having excellent adhesiveness and durability and excellent mechanical strength can be obtained.

Hereinafter, the synthetic resin powder of the present invention will be described in detail.
In the present invention, the dispersoid of the emulsion (A) is composed of a polymer having one or more unsaturated monomer units selected from ethylenically unsaturated monomers and diene monomers. Examples of the ethylenically unsaturated monomer include olefins such as ethylene, propylene, and isobutene, halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride, vinyl formate, vinyl acetate, vinyl propionate, Vinyl esters such as vinyl versatate and vinyl pivalate, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, acrylic acid Acrylic acid esters such as t-butyl, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n methacrylate -Butyl, meta Methacrylic acid esters such as i-butyl acrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate and octadecyl methacrylate, nitriles such as acrylonitrile and methacrylonitrile, allyl such as allyl acetate and allyl chloride Compound, Styrene monomers such as styrene, α-methylstyrene, p-methylstyrenesulfonic acid and sodium and potassium salts thereof, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, 3-acrylamidopropyl Trimethylammonium chloride, 3-methacrylamidopropyltrimethylammonium chloride, quaternary ammonium salt of N- (3-allyloxy-2-hydroxypropyl) dimethylamine, N- (4-allyloxy- 3-hydroxybutyl) diethylamine quaternary ammonium salt, acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, N-methylolacrylamide, methacrylamide, N-methylmethacrylamide Quaternary ammonium salts such as N-ethylmethacrylamide and N-methylolmethacrylamide, hydroxypropyltrimethylammonium methacrylate methacrylate, hydroxypropyltrimethylammonium chloride acrylate, N-vinylpyrrolidone and the like, and diene monomers Examples thereof include butadiene, isoprene, chloroprene and the like. These monomers are used alone or in combination of two or more.
Among the polymers composed of the above monomer units, vinyl ester polymers typified by vinyl acetate polymers, olefin-vinyl ester copolymers typified by ethylene-vinyl acetate copolymers, etc. This is one of the preferred embodiments of the invention.

  In the present invention, a vinyl alcohol polymer is used as the dispersant for the emulsion (A). The vinyl alcohol polymer is produced, for example, by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester. The saponification degree of the vinyl alcohol polymer is not particularly limited, but is preferably 70 to 99 mol%, more preferably 80 to 98 mol%, and still more preferably 83 to 95 mol%. When the degree of saponification is less than 70 mol%, there is a concern that water solubility, which is the original property of the vinyl alcohol polymer, is lowered. Further, when the degree of saponification exceeds 99 mol%, there is a concern that emulsion polymerization becomes unstable. The viscosity average polymerization degree (hereinafter abbreviated as polymerization degree) of the vinyl alcohol polymer is not particularly limited, but is preferably in the range of 100 to 8000, more preferably 300 to 3000, and even more preferably 300 to 2500.

The vinyl alcohol polymer may be a copolymer of an ethylenically unsaturated monomer that can be copolymerized within a range that does not impair the effects of the present invention. Examples of such ethylenically unsaturated monomers include acrylic acid, methacrylic acid, fumaric acid, (anhydrous) maleic acid, itaconic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, trimethyl- (3-acrylamide). -3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene N-vinylamides such as sodium vinylsulfonate, sodium allylsulfonate, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, and the like. In addition, in the presence of a thiol compound such as thiol acetic acid or mercaptopropionic acid, a vinyl ester monomer such as vinyl acetate is polymerized, or a vinyl ester and the ethylenically unsaturated monomer are copolymerized, A terminal modified product obtained by saponifying the obtained (co) polymer can also be used.
Moreover, it is one of the preferable aspects of this invention to use the vinyl alcohol-type polymer which has a 1, 2- glycol bond more than 1.9 mol%. The redispersibility of the powder obtained by using the vinyl alcohol polymer is improved. A method for producing a vinyl alcohol polymer having 1.9 mol% or more of 1,2-glycol bonds will be described later.

  The synthetic resin emulsion (A) used in the present invention is one or more monomers selected from ethylenically unsaturated monomers and diene monomers in the presence of the above-mentioned vinyl alcohol polymer. Is obtained by emulsion polymerization. In the production of the synthetic resin emulsion, as an initiator for emulsion polymerization, a polymerization initiator usually used for emulsion polymerization, that is, a water-soluble initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, etc. In addition, oil-soluble initiators such as azobisisobutyronitrile and benzoyl peroxide are used in redox systems alone or in combination with various reducing agents. Although there are no particular limitations on the method of using these, a method of adding them all at the beginning of the polymerization, a method of adding them continuously to the polymerization system, or the like can be employed.

In the synthetic resin emulsion (A) used in the present invention, the amount of the vinyl alcohol polymer used is not particularly limited, but is usually 2 to 30 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the monomer. More preferably, it is 3-10 weight part. When the vinyl alcohol polymer is less than 2 parts by weight, the polymerization stability of the synthetic resin emulsion is lowered, and the mechanical stability and chemical stability which are the characteristics of the synthetic resin emulsion using the vinyl alcohol polymer as a dispersant are characteristic. There is a concern that a decrease in film strength and a decrease in film strength may occur. On the other hand, when the amount of the vinyl alcohol polymer exceeds 30 parts by weight, there are concerns such as a problem of removal of reaction heat due to an increase in the viscosity of the polymerization system and a decrease in water resistance of the film.
There are no particular restrictions on the method of adding the vinyl alcohol polymer, a method of adding all at once in the initial stage of polymerization, a part of the vinyl alcohol polymer is added in the initial stage, and it is continuously added to the polymerization system during the polymerization. There are methods.
In addition, a conventionally known nonionic, anionic, cationic or amphoteric surfactant or a water-soluble polymer such as hydroxyethyl cellulose may be used in combination with the vinyl alcohol polymer.

  As a method for adding a monomer when producing the synthetic resin emulsion (A) used in the present invention, a method of adding to the polymerization system all at once, adding a part of the monomer at the initial stage, and polymerizing the rest Various methods are possible, such as a method of continuously adding the monomer, water and a dispersant previously emulsified, and a method of continuously adding to the polymerization system.

Moreover, a chain transfer agent can also be added when manufacturing the synthetic resin emulsion (A) used for this invention. The chain transfer agent is not particularly limited as long as chain transfer occurs, but a compound having a mercapto group is preferable from the viewpoint of chain transfer efficiency. Examples of the compound having a mercapto group include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan, 2-mercaptoethanol, and 3-mercaptopropionic acid.
The addition amount of the chain transfer agent is preferably 5 parts by weight or less with respect to 100 parts by weight of the monomer. When the addition amount of the chain transfer agent exceeds 5 parts by weight, the polymerization stability of the synthetic resin emulsion is lowered, and the molecular weight of the polymer forming the dispersoid is remarkably lowered, and there is a concern that the physical properties of the emulsion may be lowered. is there.

The 1,2-glycol bond content of the vinyl alcohol polymer blended in the emulsion (A) is important to be 1.9 mol% or more, more preferably 1.95 mol% or more. Furthermore, it is 2.0 mol% or more, optimally 2.1 mol% or more. If the content of 1,2-glycol bonds is less than 1.9 mol%, there is a concern that the redispersibility of the resulting powder may be reduced, and admixtures or joints for hydraulic substances such as cement or cement mortar When used as a material, excellent physical properties such as bending strength cannot be obtained. The 1,2-glycol bond content is preferably 4 mol% or less, more preferably 3.5 mol% or less, and most preferably 3.2 mol% or less. Here, the content of 1,2-glycol bonds can be determined from analysis of NMR spectra.
There is no restriction | limiting in particular in the manufacturing method of the vinyl alcohol polymer which has 1.9 mol% or more of 1, 2- glycol bonds, A well-known method can be used. As an example, a method in which vinylene carbonate is copolymerized with a vinyl ester so as to have the above 1,2-glycol bond amount, and the polymerization temperature of the vinyl ester is polymerized under pressure at a temperature higher than normal conditions, for example, 75 to 200 ° C. The method of doing is mentioned. In the latter method, the polymerization temperature is preferably 95 to 190 ° C, particularly preferably 100 to 180 ° C. Moreover, it is important to select the pressurizing condition such that the polymerization system is lower than the boiling point, preferably 0.2 MPa or more, and more preferably 0.3 MPa or more. The upper limit is preferably 5 MPa or less, and more preferably 3 MPa or less. The polymerization can be carried out by any method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization in the presence of a radical polymerization initiator, but solution polymerization, particularly solution polymerization using methanol as a solvent, Is preferred. A vinyl alcohol polymer is obtained by saponifying the vinyl ester polymer thus obtained by a usual method.

  The degree of polymerization of the vinyl alcohol polymer (B) may be selected according to various situations and is not particularly limited, but is usually preferably 100 to 3000 from the viewpoint of workability during powderization, Preferably it is 150-2000, More preferably, it is 200-1600, Optimally, it is 200-1000. On the other hand, the saponification degree of the vinyl alcohol polymer (B) is not particularly limited, but is preferably 70 to 99 mol%, more preferably 75 to 98 mol%, and further preferably 80 to 96 mol%.

  The vinyl alcohol polymer (B) may be a copolymer of an ethylenically unsaturated monomer that can be copolymerized within a range that does not impair the effects of the present invention. Examples of such ethylenically unsaturated monomers include acrylic acid, methacrylic acid, fumaric acid, (anhydrous) maleic acid, itaconic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, trimethyl- (3-acrylamide). -3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene N-vinyl amides such as sodium vinyl sulfonate, sodium allyl sulfonate, N-vinyl pyrrolidone, N-vinyl formamide, N-vinyl acetamide, etc. Le% following can be used. In addition, in the presence of a thiol compound such as thiol acetic acid or mercaptopropionic acid, a vinyl ester monomer such as vinyl acetate is polymerized, or a vinyl ester and the ethylenically unsaturated monomer are copolymerized, A terminal modified product obtained by saponifying the obtained (co) polymer can also be used.

  The compounding ratio of the vinyl alcohol polymer (B) to be blended with the synthetic resin emulsion (A) is such that the vinyl alcohol polymer (B) 1 is 100 parts by weight of the solid content (dispersoid) of the synthetic resin emulsion (A). It is suitable that it is -50 weight part, More preferably, it is 3-30 weight part, More preferably, it is 5-20 weight part, Furthermore, it is 7-20 weight part. By adding the vinyl alcohol polymer (B), the redispersibility of the emulsion powder obtained after drying is improved, the dispersibility in the hydraulic substance is improved, and the strength of the hydraulic substance using the emulsion powder is improved. Will also be excellent.

As a method for adding the vinyl alcohol polymer (B), a method in which an aqueous solution of the vinyl alcohol polymer (B) is added to the emulsion (A) is a suitable method, but the vinyl alcohol polymer (B). The method of adding the powder, flakes or pellets of (1) to the emulsion (A) is also mentioned. Moreover, when manufacturing emulsion (A) by emulsion polymerization, the method of adding a vinyl alcohol polymer (B) (lump or continuous addition) to the latter half of emulsion polymerization is also mentioned.
The synthetic resin powder of the present invention is obtained by blending the above-mentioned synthetic resin emulsion (A) with the vinyl alcohol polymer (B) and then drying, preferably spray drying. For spray drying, normal spray drying in which a fluid is sprayed to dry can be used. Depending on the type of spraying, there are disc type, nozzle type, shock wave type, etc. Any method may be used. Moreover, hot air, heating steam, etc. are used as a heat source. The drying conditions may be appropriately selected depending on the size and type of the spray dryer, the concentration, viscosity, flow rate, etc. of the synthetic resin emulsion. The drying temperature is suitably from 100 ° C to 150 ° C, and it is desirable to set other drying conditions so that a sufficiently dried powder can be obtained within this drying temperature range.

  Moreover, it is desirable to use inorganic powder (antiblocking agent) for the purpose of improving the storage stability and redispersibility in water of the synthetic resin powder of the present invention. Inorganic powder may be added to the powder after spray drying and mixed uniformly. However, when spraying the synthetic resin emulsion in the presence of inorganic powder (simultaneous spraying), uniform mixing should be performed. This is preferable. The inorganic powder is preferably fine particles having an average particle size of 0.1 to 100 μm. As the inorganic powder, fine inorganic powder is preferable, and calcium carbonate, clay, anhydrous silicic acid, aluminum silicate, white carbon, talc, alumina white and the like are used. Of these inorganic powders, anhydrous silicic acid is preferred. The amount of the inorganic powder used is preferably 20% by weight or less, more preferably 10% by weight or less, based on the performance, in view of performance. The lower limit is preferably 0.1% by weight or more, and more preferably 0.2% by weight or more. Organic fillers can also be used.

  In the synthetic resin powder of the present invention, the residue when re-dispersed in water and filtered through a 200-mesh wire mesh is a solid content, and is 0.5 wt% or less based on the total weight of the synthetic resin powder. When mixed with a hydraulic substance such as cement or cement mortar, the strength of the obtained hydraulic substance can be further improved, which is preferable. A more preferable residue amount is 0.3% by weight or less.

  In order to further improve the redispersibility of the synthetic resin powder in water, various water-soluble additives can be added. The additive is preferable because it is uniformly mixed when added to the synthetic resin emulsion before spray drying and spray dried. The amount of the water-soluble additive used is not particularly limited, and is appropriately controlled to such an extent that it does not adversely affect physical properties such as water resistance of the emulsion. Examples of such additives include hydroxyethyl cellulose, methyl cellulose, starch derivatives, polyvinyl pyrrolidone, polyethylene oxide, etc., water-soluble alkyd resins, water-soluble phenol resins, water-soluble urea resins, water-soluble melamine resins, water-soluble naphthalene sulfonic acids Examples include resins, water-soluble amino resins, water-soluble polyamide resins, water-soluble acrylic resins, water-soluble polycarboxylic acid resins, water-soluble polyester resins, water-soluble polyurethane resins, water-soluble polyol resins, and water-soluble epoxy resins.

The synthetic resin powder of the present invention (average particle diameter of 1 to 1000 μm, preferably 2 to 500 μm) can be used for various applications as it is, but it is conventionally known as long as it does not impair the effects of the present invention. Various emulsions and synthetic resin powders can also be added and used.
The synthetic resin emulsion powder of the present invention is particularly useful as an admixture for hydraulic substances such as cement or cement mortar, or as a joining material for hydraulic substances. This is clear from the examples described later. Here, examples of the hydraulic substance include hydraulic cements such as Portland cement, alumina cement, slag cement and fly ash cement, and hydraulic materials other than cement such as gypsum and plaster.
When the above-mentioned admixture for a hydraulic substance is used by blending it in a cement mortar composed of cement, aggregate and water, for example, the blending quantity of the admixture for hydraulic substance is 5 to 20% by weight with respect to the cement. Is preferred. Here, examples of the aggregate include fine aggregates such as river sand, crushed sand, colored sand and silica sand, and coarse aggregates such as river gravel and crushed stone.
When the synthetic resin emulsion powder of the present invention is used as a joining material for hydraulic substances, the synthetic resin emulsion powder is appropriately re-emulsified with water, and water such as concrete is used as the joining material (primer treatment material). The construction is carried out by applying to a hard substance substrate and then applying a hydraulic substance such as cement mortar. By using such a joining material, it is possible to impart excellent adhesion and durability, and excellent mechanical strength.

In order to further improve the dispersibility of the admixture for hydraulic substance and the joining material, various additives such as the above-mentioned water-soluble additives can be added. The additive is preferable because it is uniformly mixed when added to the synthetic resin emulsion before spray drying and spray dried. AE agent, water reducing agent, fluidizing agent, water retention agent, thickening agent, waterproofing agent, antifoaming agent and the like are appropriately used for the admixture and jointing material for hydraulic substances of the present invention.
The synthetic resin powder of the present invention can also be used for applications such as adhesives, paints, and paper processing agents. For these uses, viscosity improvers, water retention agents, tackifiers, thickeners, pigment dispersants, stabilizers, and the like are used as appropriate.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” mean weight basis.
PVA production example 1
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet and initiator inlet was charged with 2940 g of vinyl acetate, 60 g of methanol and 0.088 g of tartaric acid, and the reactor pressure was 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was increased to 1, left for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A concentration of 0.2 g / L solution in which 2,2′-azobis (cyclohexane-1-carbonitrile) (V-40) was dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed to perform bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 120 ° C. The reaction vessel pressure at this time was 0.5 MPa. Then, 2.5 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature was maintained at 120 ° C., and the polymerization was carried out by continuously adding V-40 at 10.0 ml / hr using the above initiator solution. The reactor pressure during the polymerization was 0.5 MPa. After 3 hours, the polymerization was stopped by cooling. The solid concentration at this time was 24%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 33%). To 400 g of a methanol solution of polyvinyl acetate adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution), 7 g at 40 ° C. {in polyvinyl acetate Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.015 to the vinyl acetate unit. About 2 minutes after the addition of the alkali, the gelled system was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-1). The degree of saponification of the obtained PVA (PVA-1) was 88 mol%. In addition, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization was saponified at an alkali molar ratio of 0.5, and the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. It was 1700 when the average degree of polymerization of this PVA was measured according to JIS K6726 of the usual method. The 1,2-glycol bond content of PVA can be determined from the NMR peak. After saponification to a saponification degree of 99.9 mol% or more, the sample was thoroughly washed with methanol, then dried under reduced pressure at 90 ° C. for 2 days in DMSO-D6, and a sample with a few drops of trifluoroacetic acid was added at 500 MHz. Measurement is performed at 80 ° C. using proton NMR (JEOL GX-500).
The peak derived from methine of the vinyl alcohol unit is attributed to 3.2 to 4.0 ppm (integrated value A), and the peak derived from one methine of the 1,2-glycol bond is attributed to 3.25 ppm (integrated value B). The 1,2-glycol bond content can be calculated.
1,2-glycol bond content (mol%) = B / A × 100
The amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz proton NMR (JEOL GX-500) apparatus, and found to be 2.2 mol%.

PVA production example 2
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet and initiator inlet was charged with 2400 g of vinyl acetate, 600 g of methanol and 0.088 g of tartaric acid, and the reactor pressure was 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was increased to 1, left for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A concentration of 0.2 g / L solution in which 2,2′-azobis (cyclohexane-1-carbonitrile) (V-40) was dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed to perform bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 120 ° C. The reaction vessel pressure at this time was 0.5 MPa. Then, 2.5 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature was maintained at 120 ° C., and the polymerization was carried out by continuously adding V-40 at 10.0 ml / hr using the above initiator solution. The reactor pressure during the polymerization was 0.5 MPa. After 3 hours, the polymerization was stopped by cooling. The solid concentration at this time was 24%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 33%). To 400 g of a methanol solution of polyvinyl acetate adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution), 7 g at 40 ° C. {in polyvinyl acetate Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.015 to the vinyl acetate unit. About 2 minutes after the addition of the alkali, the gelled system was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-2). The degree of saponification of the obtained PVA (PVA-2) was 98 mol%. In addition, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization was saponified at an alkali molar ratio of 0.5, and the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. When the average degree of polymerization of the PVA was measured according to JIS K6726 of a conventional method, it was 500. The amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz proton NMR (JEOL GX-500) apparatus, and found to be 2.2 mol%.

PVA production example 3
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet and initiator inlet was charged with 2850 g of vinyl acetate, 150 g of methanol and 0.086 g of tartaric acid, and the reactor pressure was 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was increased to 1, left for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A 0.1 g / L solution having 2,2′-azobis (N-butyl-2-methylpropionamide) dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed by bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 150 ° C. The reactor pressure at this time was 1.0 MPa. Next, 15.0 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature is maintained at 150 ° C., and 2,2′-azobis (N-butyl-2-methylpropionamide) is continuously added at 15.8 ml / hr using the above initiator solution. Carried out. The reactor pressure during the polymerization was 1.0 MPa. After 4 hours, the polymerization was stopped by cooling. The solid concentration at this time was 35%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 33%). 11.6 g {polyacetic acid at 40 ° C. was added to 400 g of a polyvinyl acetate methanol solution adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution). Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.025} to vinyl acetate units in vinyl. After about 3 minutes after the addition of the alkali, the gelled material was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-3). The degree of saponification of the obtained PVA (PVA-3) was 98 mol%. Further, after saponification of a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization at an alkali molar ratio of 0.5, the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. It was 1000 when the average degree of polymerization of this PVA was measured according to JIS K6726 of the usual method. When the amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz proton NMR (JEOL GX-500) apparatus, it was 2.5 mol%.

PVA production example 4
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet and initiator inlet was charged with 2700 g of vinyl acetate, 300 g of methanol and 0.081 g of tartaric acid, and the reactor pressure was 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was increased to 1, left for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A 0.05 g / L solution having a concentration of 2,2′-azobis (N-butyl-2-methylpropionamide) dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed to perform bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 180 ° C. The reactor pressure at this time was 1.6 MPa. Next, 0.4 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature was maintained at 180 ° C., and 2,2′-azobis (N-butyl-2-methylpropionamide) was continuously added at 10.6 ml / hr using the above initiator solution. Carried out. The reactor pressure during the polymerization was 1.6 MPa. After 4 hours, the polymerization was stopped by cooling. The solid concentration at this time was 27%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 33%). 13.3 g {polyacetic acid at 40 ° C. was added to 333 g of a polyvinyl acetate methanol solution (100 g of polyvinyl acetate in the solution) prepared by adding methanol to the obtained polyvinyl acetate solution to a concentration of 30%. Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.025} to vinyl acetate units in vinyl. After about 3 minutes after the addition of the alkali, the gelled material was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-4). The degree of saponification of the obtained PVA (PVA-4) was 98 mol%. Further, after saponification of a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization at an alkali molar ratio of 0.5, the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. When the average degree of polymerization of the PVA was measured according to JIS K6726 of a conventional method, it was 500. When the amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz proton NMR (JEOL GX-500) apparatus, it was 2.9 mol%.

PVA production example 5
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet and initiator inlet was charged with 2850 g of vinyl acetate, 150 g of methanol and 0.086 g of tartaric acid, and the reactor pressure was 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was increased to 1, left for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A 0.1 g / L solution having 2,2′-azobis (N-butyl-2-methylpropionamide) dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed by bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 150 ° C. The reactor pressure at this time was 1.0 MPa. Next, 15.0 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature is maintained at 150 ° C., and 2,2′-azobis (N-butyl-2-methylpropionamide) is continuously added at 15.8 ml / hr using the above initiator solution. Carried out. The reactor pressure during the polymerization was 1.0 MPa. After 4 hours, the polymerization was stopped by cooling. The solid concentration at this time was 35%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 33%). To 400 g of a methanol solution of polyvinyl acetate adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution), 7 g at 40 ° C. {in polyvinyl acetate Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.015 to the vinyl acetate unit. After about 3 minutes after the addition of the alkali, the gelled material was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-5). The degree of saponification of the obtained PVA (PVA-5) was 88 mol%. Further, after saponification of a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization at an alkali molar ratio of 0.5, the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. It was 1000 when the average degree of polymerization of this PVA was measured according to JIS K6726 of the usual method. When the amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz proton NMR (JEOL GX-500) apparatus, it was 2.5 mol%.

Emulsion production example 1
A pressure-resistant autoclave equipped with a nitrogen inlet, a thermometer, and a stirrer was charged with 80 parts of a 9.5% aqueous solution of PVA-217 (manufactured by Kuraray Co., Ltd., polymerization degree 1700, saponification degree 88 mol%), and the temperature was raised to 60 ° C. After warming, nitrogen substitution was performed. After charging 80 parts of vinyl acetate, ethylene was pressurized to 4.9 MPa, and 2 g of 0.5% hydrogen peroxide aqueous solution and 0.3 g of 2% Rongalite aqueous solution were injected to initiate polymerization. When the residual vinyl acetate concentration reached 10%, ethylene was released, the ethylene pressure was set to 2.0 MPa, and 0.3 g of a 3% aqueous hydrogen peroxide solution was injected to complete the polymerization. There was no aggregation during the polymerization and the polymerization stability was excellent, and an ethylene-vinyl acetate copolymer emulsion (Em-1) having a solid content concentration of 55% and an ethylene content of 18% by weight was obtained.

Emulsion production example 2
In a glass container equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen inlet, and a stirrer, PVA having a mercapto group at the end (polymerization degree 550, saponification degree 88.3 mol%, mercapto group content 3.3) × 10 ⁻⁵ equivalent / g) 5 parts and 90 parts of ion-exchanged water were charged and completely dissolved at 95 ° C. Next, after adjusting the pH to 4 with dilute sulfuric acid, 10 parts of methyl methacrylate, 10 parts of n-butyl acrylate and 0.1 part of n-dodecyl mercaptan were added while stirring at 150 rpm, and the temperature was raised to 70 ° C. after nitrogen substitution. . Polymerization was started by adding 5 parts of 1% potassium persulfate, and a mixture of 40 parts of methyl methacrylate, 40 parts of n-butyl acrylate and 0.4 part of n-dodecyl mercaptan was continuously added over 2 hours. . Three hours after the start of the polymerization, the conversion was 99.5% and the polymerization was terminated. A stable methyl methacrylate / n-butyl acrylate copolymer emulsion (Em-2) having a solid content concentration of 52% was obtained.

Emulsion production example 3
An emulsion (Em-3) was obtained in the same manner as in Emulsion Production Example 1 except that PVA-1 obtained in PVA Production Example 1 was used instead of PVA-217 in Emulsion Production Example 1.

  A mixture of 100 parts of the ethylene-vinyl acetate copolymer emulsion (A) (Em-1) solid content obtained in Emulsion Production Example 1 and 200 parts of a 5% aqueous solution of PVA-2 obtained in PVA Production Example 2, 2% anhydrous silicic acid fine powder (average particle size: 2 μm) based on the solid content of the emulsion was separately sprayed separately into hot air at 120 ° C. and dried to obtain an emulsion powder having an average particle size of 20 μm.

(Emulsion powder performance evaluation)
100 parts of ion-exchanged water at 20 ° C. was added to 100 parts of the emulsion powder and sufficiently stirred with a stirrer, and the following physical properties were evaluated. The results are shown in Table 1.
-Redispersibility: The redispersed emulsion was filtered through a 200 mesh stainless steel wire mesh, the filtration residue was dried at 105 ° C for 5 hours, and the ratio of the filtration residue was measured.
Filtration residue (%) = (filter residue after drying / emulsion powder weight used for redispersion) × 100
The smaller the filtration residue, the more a hydraulic product with superior strength is obtained when the emulsion powder is used as an admixture or jointing material for hydraulic materials. According to the present invention, an emulsion powder having a filtration residue of 5% or less (Table 1) can be obtained.
-State after re-dispersion: The state of the re-dispersed emulsion was observed visually and with an optical microscope, and judged according to the following criteria.
◎ Uniform redispersion with an average particle size of 50 μm or less ○ Uniform redispersion with no undispersed matter
Δ: Redispersed, but undispersed material is observed.
X Not redispersed / Film-forming property: The re-dispersed material was cast and dried on a glass plate at 50 ° C., and the film-forming property was judged according to the following criteria.
○ A uniform film is obtained and a tough film is obtained.
△ Although it becomes a film, it is fragile.
X A uniform film cannot be obtained.
Water resistance (elution rate of film in water): The redispersed emulsion was formed at 20 ° C. to obtain a film (film thickness 100 μm). The film was immersed in 20 ° C. water for 24 hours, and the elution rate was calculated by the following formula.
Elution rate (%) = {1− (absolute dry weight after immersion) / (absolute dry weight of film before immersion)} × 100
Film dry weight before immersion; film weight before immersion (water content)-(film weight before immersion (water content) x film moisture content (%) / 100)
Absolute dry weight of film after immersion; weight of the absolute dry film after immersion at 105 ° C.
The smaller the elution rate, the better the water resistance and redispersibility. According to the present invention, an emulsion powder having an elution rate of 7% or less (Table 1) can be obtained.
Standing stability: The redispersed emulsion was allowed to stand at 20 ° C. and 0 ° C., and the state was observed after 1 week, and judged according to the following criteria.
○ No change,
△ Thickening is observed,
× Gelled gel content:
An emulsion obtained by redispersion in water at 20 ° C. (redispersion at a ratio of 100 parts of emulsion powder to 100 parts of ion-exchanged water at 20 ° C.) was cast on a PET film at 20 ° C. and 65% RH, The film was dried for 7 days to obtain a dry film having a thickness of 500 μm. A sample obtained by punching this film to a diameter of 2.5 cm was subjected to Soxhlet extraction with acetone for 24 hours, followed by extraction for 24 hours in boiling water, and the insoluble content (gel content) of the film after extraction was determined.
Gel content (%) = absolute dry weight of film after extraction / absolute dry weight of film before extraction × 100
Film absolute dry weight before extraction = film weight before extraction (water content) − {film weight before extraction (water content) × water content of film (%) / 100}
* Moisture content of the film: The film (a sample different from the sample extracted with acetone and boiling water) is completely dried at 105 ° C. for 4 hours, and the moisture content of the film is obtained in advance.
* Extra dry weight of the film after extraction: The weight of the dry film after extraction at 105 ° C. for 4 hours.
The larger the gel content, the more vinyl alcohol polymer (B) is grafted onto the dispersoid (polymer), and the redispersibility of the emulsion powder is further improved. According to the present invention, an emulsion powder having a gel content of 20% or more (Table 1) can be obtained.

(Performance evaluation of admixtures for hydraulic materials)
Performance as an admixture for cement mortar Properties test of cement mortar 1) Mortar composition:
Hydraulic material admixture / cement weight ratio = 0.10
Sand / cement weight ratio = 3.0, water / cement weight ratio = 0.6
2) Slump value: Measured according to JIS A-1173
(Indicator of dispersibility in cement mortar)
3) Bending strength: measured according to JIS A-6203 4) Compressive strength: measured results according to JIS A-6203 are shown in Table 2.

(Performance evaluation of joint material for hydraulic materials)
Performance as a cement mortar joint material The following test was conducted using the hydraulic material admixture obtained above as a joint material.
Adhesive strength test 1) Test substrate As a concrete substrate used for the test, 300 parts of Portland cement, 800 parts of silica sand, 1000 parts of coarse aggregate (ballast) and 180 parts of water, which are standard blends in architecture, are mixed. Then, it was cast in a size of 300 mm × 300 mm × thickness 50 mm with a plywood mold and cured for 28 days in a test room {temperature 20 ° C., relative humidity (RH) 65%}.

2) Coated mortar The composition of the coated mortar used in the test is cement 1 and aggregate (standard sand) 2 by weight ratio, and the water-cement ratio is adjusted so that the flow value becomes 170 ± 5. It knead | mixed according to prescription | regulation of 9.4 of R5201.
In addition, the normal Portland cement prescribed | regulated to JISR5210 (Portland cement) was used as a cement, and the Toyoura standard sand prescribed | regulated to 9.2 of JISR5210 was used as an aggregate.

3) Method for preparing test body The joint material was uniformly applied to the surface of the test substrate of 1) with a brush, and left in an atmosphere of a temperature of 20 ° C. and 65% RH for 24 hours. The application amount of the joining material was 50 g / m ² as a solid content. Next, apply the mortar of 2) above with a gold trowel so that the thickness is 6 mm, and after curing in an atmosphere of 20 ° C. and 80% RH or more for 48 hours, further curing in the test room for 26 days. A test body was obtained.

4) Bond strength test in standard state After the mortar surface of the specimen prepared in 3) above was cut into a size of 40 mm × 90 mm until reaching the substrate, the bond strength was measured according to the test method specified in 5.6 of JIS A6916. The test was performed and the average value of the measured values at five locations was obtained. The results are shown in Table 2 as joint properties.

Comparative Example 1
In Example 1, instead of PVA-2, normal PVA (PVA-6: polymerization degree 500, saponification degree 98.5 mol%, 1,2-glycol bond amount 1.6 mol%, manufactured by Kuraray Co., Ltd.) An emulsion powder was obtained in the same manner as in Example 1 except that PVA-105) was used. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that PVA-3 obtained in PVA Production Example 3 was used instead of PVA-2. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that PVA-4 obtained in PVA Production Example 4 was used instead of PVA-2. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that PVA-5 obtained in PVA Production Example 5 was used instead of PVA-2. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

Comparative Example 2
In Example 1, instead of PVA-2, normal PVA (PVA-7: polymerization degree 1000, saponification degree 88 mol%, 1,2-glycol bond amount 1.6 mol%, Kuraray Co., Ltd. PVA-) An emulsion powder was obtained in the same manner as in Example 1 except that 210) was used. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

Comparative Example 3
In Example 1, an emulsion powder was obtained in the same manner as Example 1 except that PVA-2 was not used. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. However, the redispersibility was extremely poor, the film forming property was poor, and the dissolution rate and stability could not be measured. The results are also shown in Table 1 and Table 2.

  In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that 200 parts of a 5% aqueous solution of PVA-2 was changed to 100 parts. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

Comparative Example 4
In Comparative Example 1, an emulsion powder was obtained in the same manner as Comparative Example 1 except that 200 parts of a 5% aqueous solution of PVA-6 was changed to 100 parts. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. However, the redispersibility was extremely poor, the film forming property was poor, and the dissolution rate and stability could not be measured. The results are also shown in Table 1 and Table 2.

  In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that 200 parts of a 5% aqueous solution of PVA-2 was changed to 300 parts. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  An emulsion powder was obtained in the same manner as in Example 1 except that 40 parts of a 5% aqueous solution of PVA-2 was changed to 40 parts. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  In Example 1, an emulsion powder was obtained in the same manner as in Example 1 except that 200 parts of a 5% aqueous solution of PVA-2 was changed to 500 parts. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  In Example 1, the same procedure as in Example 1 was used except that instead of Em-1, the methyl methacrylate / n-butyl acrylate copolymer emulsion (A) (Em-2) prepared in Emulsion Production Example 2 was used. An emulsion powder was obtained. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

Comparative Example 5
In Example 9, emulsion powder was obtained in the same manner as in Example 9 except that ordinary PVA (PVA-6) was used instead of PVA-2. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

  In Example 1, emulsion powder was obtained in the same manner as in Example 1 except that Em-3 was used instead of Em-1. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Tables 1 and 2.

Comparative Example 6
In Example 1, emulsion powder was obtained in the same manner as in Example 1 except that Em-3 was used instead of Em-1 and PVA (B) (PVA-2) was not used. The physical properties of the obtained emulsion powder were evaluated in the same manner as in Example 1. The results are also shown in Tables 1 and 2.

Comparative Example 7
In Example 10, instead of PVA (B) (PVA-2), PVA (B) {PVA-6: polymerization degree 500, saponification degree 98.5 mol%, 1,2-glycol bond amount 1.6 mol %, Emulsion powder was obtained in the same manner as in Example 10 except that “PVA105” manufactured by Kuraray Co., Ltd. was used. The results are also shown in Tables 1 and 2.

According to the present invention, it is possible to obtain a synthetic resin powder having excellent redispersibility, further excellent water resistance, and excellent film forming property when redispersed and excellent storage stability at low temperatures. Also, by using this synthetic resin powder, it is excellent in dispersibility in hydraulic materials such as cement or cement mortar, and can further impart excellent strength to the obtained hydraulic material. Is obtained. Further, by using the synthetic resin powder of the present invention, a joining material for a hydraulic substance having excellent adhesiveness and durability and excellent mechanical strength can be obtained.

Claims (8)

  An emulsion having a vinyl alcohol polymer as a dispersant and a polymer having one or more unsaturated monomer units selected from ethylenically unsaturated monomers and diene monomers as a dispersoid (A ) And a synthetic resin powder obtained by drying a composition in which a vinyl alcohol polymer (B) having a 1,2-glycol bond of 1.9 mol% or more is blended.   The synthetic resin according to claim 1, wherein 1 to 50 parts by weight of vinyl alcohol polymer (B) having 1,2-glycol bond of 1.9 mol% or more is blended with respect to 100 parts by weight of solid content of emulsion (A). Powder.   The polymer having one or more unsaturated monomer units selected from ethylenically unsaturated monomers and diene monomers is a vinyl ester polymer or an olefin-vinyl ester copolymer. The synthetic resin powder according to claim 1 or 2.   The synthetic resin powder according to any one of claims 1 to 3, wherein the vinyl alcohol polymer used in the emulsion (A) is a vinyl alcohol polymer having 1.9 mol% or more of 1,2-glycol bonds.   The synthetic resin powder according to any one of claims 1 to 4, wherein when the synthetic resin powder is re-dispersed in water and filtered through a 200 mesh wire net, the residue is 0.5 wt% or less in solid content. Resin powder.   The synthetic resin powder according to any one of claims 1 to 5, wherein the drying is spray drying.   The synthetic resin powder according to any one of claims 1 to 6, wherein the synthetic resin powder contains an inorganic powder. The admixture or joint material for hydraulic substances which consists of the synthetic resin powder in any one of Claims 1-7.