JPH028986B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The polymer cement composition of the present invention is a coating material with a long pot life. The composition of the present invention is useful as a base preparation material for new construction or repair of structures made of wood, concrete, etc., flooring materials, finishing coating materials, coating materials for metals such as steel pipes, etc. [Prior art] In general, a polymer cement composition is a mixture of an aqueous resin dispersion (emulsion) at a ratio of 3 to 50% by weight (resin solid content in the emulsion) based on the sum of Portland cement and aggregate. (Japanese Patent Publication No. 48-44327, 51-1526, 52-
No. 81331, No. 54-66937, No. 55-10433, No. 55
−104955, No. 56-17968, No. 56-145148,
No. 56-164048, Special Publication No. 56-33334). The advantages of these polymer cement compositions are that (1) the tensile strength of the cement is improved compared to compositions that do not contain an aqueous resin dispersion. (2) Improve adhesion to various base materials, such as architectural structures. (3) Improve freeze-thaw resistance. (4) Improve water retention. (5) Reduce drying shrinkage. etc. can be mentioned. [Problems with the prior art] However, while there are advantages as shown above, there are problems with reactive groups such as carboxyl groups (-COOH) in the aqueous resin dispersion and components in cement.
For example, due to the reaction with Ca ⁺⁺ , polymer cement has the disadvantage that its pot life is shorter than mortar without emulsion, which causes various problems in working. [Specific measures to solve the problem] By adding the water-soluble polymer shown in component (C) below to the resin aqueous dispersion and further adding hydraulic cement, the advantages of the polymer cement can be achieved without impairing the advantages of the polymer cement. The pot life can be significantly extended. That is, in the present invention, (A) component: resin aqueous dispersion (B) component: hydraulic cement (C) component: 20% of hydroxyalkyl acrylate
A water-soluble polymer having a hydroxyl group in the molecule obtained by polymerizing a vinyl monomer containing ~100% by weight. The ratio of hydraulic cement is 50 to 3,500 parts by weight, and the solid content of the water-soluble polymer (C) is 0.1 to 10 parts by weight per 100 parts by weight of the hydraulic cement (B). The purpose of the present invention is to provide a polymer cement composition whose pot life can be significantly extended by blending the components in the appropriate proportions. In the present invention, the resin aqueous dispersion of component (A) refers to the following vinyl monomer alone in the presence of a polymerization initiator using an anionic or nonionic surfactant or a protective colloid agent as an emulsifier. Alternatively, it is an aqueous resin emulsion obtained by emulsion polymerizing two or more types in a conventional manner. Such copolymerizable vinyl monomers include 2-ethylhexyl acrylate, n-butyl acrylate, ethyl acrylate, methyl acrylate, isopropyl acrylate, n-propyl acrylate,
Styrene, butadiene, 2-ethylhexyl methacrylate, n-propyl methacrylate, methyl methacrylate, n-butyl methacrylate, ethyl methacrylate, ethylene, acrylonitrile, vinyl chloride, vinylidene chloride, acrylic acid, methacrylic acid, itaconic acid, maleic acid One or more types of acid, acrylamide, methacrylamide, N-methylol methacrylamide, etc. are used. The resin aqueous dispersion of component (A) has a minimum film-forming temperature below the working temperature of the polymer cement composition (if air-dried, the temperature at that time; if forced drying using a heating means, the heating temperature at that time). It is fine as long as it shows. In addition, when the resin aqueous dispersion has a minimum film-forming temperature higher than the usage temperature of the polymer cement composition, a film-forming aid such as Texanol or butyl cellosolve or a plasticizer such as dioctyl phthalate or butyl benzyl phthalate may be added to the aqueous dispersion. and use the film at an apparent film-forming temperature below the operating temperature. The aqueous resin dispersion of component (A) is produced with a resin concentration of 40 to 60% by weight by emulsion polymerizing the polymerizable vinyl monomer using an emulsifier or a protective colloid. It may also be used after diluting with water. The resin particle size in the aqueous dispersion is
0.1 to 3 microns is common. Examples of emulsifiers include the following. Sodium dialkyl sulfone succinate, sodium salt of sulfated oils, sodium salt, sodium salt, potassium salt and ammonium alkyl sulfate of alkyl sulfonic acids, alkali metal salts of sulfonic acids, oxyalkylated _C12 - _C24-
alkali metal salts of fatty alcohols and oxyalkylated alkylphenols, as well as other oxyethylated fatty acids, fatty alcohols and/or fatty amides,
Oxyethylated alkylphenols, as well as sodium salts of fatty acids such as sodium stearate and sodium oleate. Examples of protective colloid agents include polyvinyl alcohol, polyacrylic acid sodium salt, CMC, polyvinylpyrrolidone, and the like. The emulsifier or protective colloid is often used in an amount of 0.2 to 3% by weight based on the resin content. Next, the hydraulic cement of component (B) includes ordinary Portland cement called Portland cement, white cement, early strength cement, ultra early strength cement, mixed cement (blast furnace cement, silica cement, fly ash cement), etc. It will be done. Component (B), the hydraulic cement, is used in an amount of 50 to 3,500 parts by weight, preferably 80 to 2,000 parts by weight, based on 100 parts by weight of the solid content of the copolymer in the aqueous dispersion of (A). It will be done. If it is less than 50 parts by weight, it can only be expected to function as an aggregate for cement, so it cannot be applied thickly and the strength of the film will be weak. On the other hand, if the amount exceeds 3500 parts by weight, the above-mentioned (1)~
The effect of (5) is not achieved. A part (80% by weight or less) of the cement of component (B),
Talc, mica, diatomaceous earth, kaolin, quartz, iron powder, fly ash, ultra white, titanium oxide, calcium carbonate, asbestos powder, white carbon, zirconia, carbon black, perlite, zinc oxide, mica, expanded polystyrene particles, perlite particles , may be replaced with aggregate such as glass sphere particles. When these aggregates are used, in addition to the emulsion resin of component (A), the hydraulic cement of component (B) also has a binder function, so that these aggregates are prevented from falling off from the coating. Component (C), a water-soluble polymer having a hydroxyl group, is produced by polymerizing a vinyl monomer containing 20 to 100% by weight of hydroxyacrylate, preferably (a) hydroxyalkyl acrylate.
20-80% by weight (b) Acrylamide and/or methacrylamide 1-50% by weight (c) Vinyl monomers other than components (a) and (b) above
It is a water-soluble polymer with a molecular weight of 1,000 to 500,000 obtained by copolymerizing 0 to 79% by weight. As the hydroxyalkyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate,
Hydroxypropyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. can be used. Other copolymerizable vinyl monomers include 2-ethylhexyl acrylate, n-butyl acrylate, ethyl acrylate, methyl acrylate, isopropyl acrylate, n-propyl acrylate, styrene, butadiene, and 2-ethylhexyl methacrylate. , n-propyl methacrylate, methyl methacrylate, n-methacrylate
Examples include butyl, ethyl methacrylate, ethylene, acrylonitrile, vinyl chloride, vinylidene chloride, acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamide, methacrylamide, N-methylolmethacrylamide, vinyl acetate, and the like. However, among the above, when using an unsaturated carboxylic acid, it is preferable to use it in an amount of 1% by weight or less because the influence of reactivity with cement components is small. Further, in particular, the combination of acrylamide and methacrylamide has the effect of reducing drying shrinkage of the obtained cured polymer cement. Note that if the amount of hydroxyacrylic acrylate used is less than 20% by weight, the expected pot life cannot be obtained. The molecular weight of the water-soluble polymer as component (C) is 1000 to 500000, preferably 2000 to 500000.
Use 100000. If the molecular weight is less than 1000, the expected pot life will not be obtained;
When it exceeds 500,000, the cohesive force becomes too strong,
Mixing stability deteriorates. The water-soluble polymer as component (C) is used in a solid content of 0.1 to 10 parts by weight, preferably 0.2 to 5.0 parts by weight, based on 100 parts by weight of the hydraulic cement (B). If it is less than 0.1 parts by weight, the expected pot life cannot be obtained, and if it exceeds 10 parts by weight,
The water retention becomes too high and the curing of the polymer cement composition is significantly slowed down. In addition, before or during the emulsion polymerization to obtain the aqueous resin dispersion of the component (A), the water-soluble polymer of the component (C) is added to water, and the emulsion polymerization is performed to form the resin dispersion with the component (A).
A mixture of components (C) may be prepared simultaneously. In addition to these components (A), (B), and (C), viscosity stabilizers, antifoaming agents, alcohol, isopropanol,
Solvents such as toluene, plasticizers, etc. can be blended. The aqueous resin dispersion composition of the present invention can be applied once to concrete, mortar, slate, iron, aluminum, fiber, wood, glass, and plastics such as vinyl chloride and polyethylene by methods such as brushing or spraying with a spray gun. It is possible to form a coating film with a thickness from the micron order to several millimeters. Next, the present invention will be explained in detail using Examples and Comparative Examples. Parts and percentages in Examples and Comparative Examples are by weight unless otherwise specified. Example 1 2-ethylhexyl acrylate (2EHA) 35 parts n-butyl acrylate (BA) 35 parts styrene (St) 26 parts methacrylamide (M-AAmide) 3 parts acrylic acid (AA) 2 parts sodium dodecylbenzenesulfonate 1.0 part polyoxyethylene nonylphenol ether
A mixture of 1.0 parts potassium persulfate, 1.0 parts ion-exchanged water, and 100 parts was subjected to an emulsion polymerization reaction at 90°C for 4.5 hours.
An emulsion having a solid content concentration of 50%, a resin particle size of 0.5 microns, and a minimum film forming temperature of 0° C. or lower was obtained. Separately, 2-hydroxyethyl acrylate (2HEA)
A mixture of 60 parts acrylamide (AAamide), 40 parts potassium persulfate, 2 parts ion-exchanged water, and 500 parts was polymerized at 90°C for 4.5 hours to obtain a water-soluble polymer aqueous solution with a solid concentration of 20% and a molecular weight of approximately 5000. I got it. To 100 parts of the resin aqueous emulsion (emulsion),
10 parts of the above water-soluble polymer aqueous solution was added, and ordinary Portland cement manufactured by Ube Industries, Ltd. (specific gravity
3.1) A polymer cement mortar paint was prepared by blending 800 parts of No. 6 silica sand and 170 parts of water. The pot life and mixing stability of this paint were evaluated using the following method. [Evaluation method] Pot life: Measure the flow value immediately after mixing and after standing still for 60 minutes in accordance with the flow test of JIS-K 5201 physical test method for cement, and calculate the pot life from the rate of change. It was evaluated as follows. Rate of change (%) = (Flow value immediately after mixing) - (Flow value after standing still for 60 minutes) / (Flow value immediately after mixing) x 100 Mixing stability: When a water-soluble polymer aqueous solution is mixed into a resin aqueous emulsion. Furthermore, when ordinary Portland cement and silica sand were mixed, if the paint existed stably, it was evaluated as good (〇), and if it became unstable due to agglomeration, it was evaluated as poor (x). Example 2, Comparative Examples 1 and 2 Polymer cement mortar paints were prepared and evaluated in the same manner as in Example 1, except that the amount of the water-soluble polymer aqueous solution added was changed as shown in Table 1. The results are shown in the same table.

【table】

〔Evaluation methods〕

Drying shrinkage: Put 300g of paint into a plastic container with a diameter of 5cm and a height of 10cm, tamp it 15 times with an iron rod of 20cm in length and 1cm in diameter, then cover with a lid and store at a temperature of 20℃ and a humidity of 65%.
The paint was left for two weeks to harden. Measure the diameter of the cured polymer cement and calculate the drying shrinkage rate using the following formula. Drying shrinkage rate (%) 5 cm - Diameter of polymer cement composition after curing (cm)/5 cm x 100 The results are shown in Table 4.

【table】

【table】

【table】

[Table] Examples 6 to 7 As shown in Table 5, a polymer cement mortar paint was prepared in the same manner as in Example 1, except that the proportions of Portland cement and silica sand were changed, and evaluation was performed in the same manner as in Example 1. did. The results are shown in the same table.

【table】

[Table] Examples 8 to 9, Comparative Examples 5 to 6 Emulsion polymerization was carried out in the same manner as in Example 1 using the vinyl monomers shown in Table 6 to obtain an aqueous resin emulsion. A water-soluble polymer aqueous solution, ordinary Portland cement, and No. 6 silica sand were blended into 100 parts of this emulsion in the proportions shown in Table 7 to prepare a polymer cement mortar paint. This was evaluated in the same manner as in Example 1. The results are shown in Table 7.

【table】

【table】

【table】

Claims (1)

[Scope of Claims] 1 (A) component: resin aqueous dispersion (B) component: hydraulic cement (C) component: hydroxyalkyl acrylate
A water-soluble polymer having a hydroxyl group in the molecule obtained by polymerizing a vinyl monomer containing 20 to 100% by weight.For 100 parts by weight of the solid content of the resin in the aqueous dispersion of (A), 50 to 3,500 parts by weight of hydraulic cement, and 0.1 to 10 parts by weight of water-soluble polymer as component (C) per 100 parts by weight of hydraulic cement as component (B). A polymer cement composition that is blended in the proportion of 2. Claim No. 2, characterized in that the hydroxyalkyl acrylate is a compound selected from 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and 2-hydroxypropyl methacrylate. Composition according to item 1. 3 The water-soluble polymer of component (C) is (a) hydroxyalkyl acrylate.
20-80% by weight (b) Acrylamide and/or methacrylamide 1-50% by weight (c) Vinyl monomers other than components (a) and (b) above
The composition according to claim 1, which is a water-soluble polymer having a molecular weight of 1,000 to 500,000 obtained by copolymerizing 0 to 79% by weight.