JPH028985B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The polymer cement composition of the present invention provides a coating material with little drying shrinkage. 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, and coating materials for metals such as steel pipes. [Prior Art] In general, a polymer cement composition is a mixture of aqueous resin emulsion and cement and aggregate.
3 to 50% by weight (resin solid content in emulsion) (Japanese Patent Application Laid-Open No. 48-44327,
No. 51-1526, No. 52-81331, No. 54-66937,
No. 55-10433, No. 55-104955, No. 56-17968
No. 56-145148, No. 56-164048, Special Publication No. 1983
−33334). The advantages of these polymer cement compositions, compared to those without emulsion, are (1) improved tensile strength of the cement; (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, among these, the drying shrinkage (5) depends on the type of resin aqueous emulsion (hereinafter referred to as "resin aqueous dispersion"), the composition of the resin, the film forming temperature, etc. Their effects vary greatly, and even if they are effective, their effects are not absolute; depending on the amount of the resin added to the cement, the drying shrinkage of polymer cement products may increase due to shrinkage of the resin. . [Specific measures to solve the problem] By adding water-soluble acrylamide polymer to the aqueous resin dispersion and adding hydraulic cement, the amount of the aqueous resin dispersion to be mixed with the hydraulic cement can be varied over a fairly wide range. Even if it is changed, the drying shrinkage of the polymer cement can be reduced. That is, the present invention comprises: (A) Component: Resin aqueous dispersion (B) Component: Hydraulic cement (C) Component: Water-soluble acrylamide polymer or methacrylamide polymer having a molecular weight of 1,000 to 500,000 Aqueous dispersion of the above (A) The ratio of (B) hydraulic cement to 100 parts by weight of the solid resin of the liquid is 50 to 3500 parts by weight, and the hydraulic cement of component (B) is 100 parts by weight.
The present invention provides a polymer cement composition in which component (C), a water-soluble acrylamide polymer or methacrylamide polymer, is blended in an amount of 0.2 to 10 parts by weight based on the solid content of the polymer. 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 polymerization of two or more types by a conventional method. 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 acids, acrylamide, methacrylamide, N-methylol methacrylamide, etc. are used. The aqueous resin 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 is something. In addition, when using an aqueous dispersion whose film-forming temperature is higher than the operating temperature, add a film-forming agent such as Texanol or butyl cellosolve, or a plasticizer such as dioctyl phthalate or butyl benzyl phthalate to the aqueous dispersion. It is also possible to use a film formed at a lower 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 emulsion resin particle size 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) to
The effect of (5) is not achieved. (B) Talc if it is within 80wt% of the cement component.
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, glass It may be replaced with aggregate such as spherical 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. The water-soluble acrylamide polymer or methacrylamide polymer as component (C) is used in a solid content of 0.2 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the hydraulic cement (B). used. If it is less than 0.2 parts by weight, no effect of reducing drying shrinkage can be expected, and if it exceeds 10 parts by weight, the water resistance of the dried polymer cement may deteriorate. The molecular weight of the water-soluble acrylamide polymer or methacrylamide polymer as component (C) is 1000 to 500000, preferably 2000 to 500000.
Use 100000. If the molecular weight is less than 1,000, no effect of reducing drying shrinkage can be expected. Conversely, if the molecular weight exceeds 500,000, the cohesive force will be too strong and the mixing stability will deteriorate. As the water-soluble acrylamide polymer or methacrylamide polymer, a homopolymer of acrylamide or methacrylamide is preferable, but the monomer ratio is less than 50% by weight (acrylamide or methacrylamide is 50% by weight or more).
If so, it may be a copolymerized product with other copolymerizable monomers. If the monomer ratio of acrylamide or methacrylamide is less than 50%, a satisfactory effect of reducing drying shrinkage cannot be obtained. As a copolymerizable monomer, acrylic acid 2
-Ethylhexyl, n-butyl acrylate, ethyl acrylate, methyl acrylate, isopropyl acrylate, n-propyl acrylate, styrene, butadiene, 2-ethylhexyl methacrylate, n-propyl methacrylate, methyl methacrylate, n-methacrylate・Butyl, ethyl methacrylate, ethylene, acrylonitrile, vinyl chloride, vinylidene chloride, acrylic acid, methacrylic acid, itaconic acid, maleic acid, N-methylolmethacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate , 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and the like. In addition, the water-soluble acrylamide polymer or methacrylamide polymer of component (C) is poured into water in advance during the production of the resin aqueous dispersion of component (A), and then the other monomers are poured into water. A mixture of components (A) and (C) may be prepared by carrying out emulsion polymerization, or component (C) may be added during emulsion polymerization of component (A) to further complete the emulsion polymerization ( A mixture of component A) and component (C) may be prepared. In addition to these components (A), (B), and (C), viscosity stabilizers, antifoaming agents, solvents, 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) 1 part sodium dodecylbenzenesulfonate 1.5 parts polyoxyethylene nonyl phenol ether
A mixture of 1.5 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, a mixture of 100 parts of acrylamide (AAamide), 2 parts of potassium persulfate, and 500 parts of ion-exchanged water was polymerized at 90°C for 4.5 hours to obtain a water-soluble acrylamide polymer with a solid concentration of 20% and a molecular weight of about 5000. Ta. To 100 parts of the resin aqueous emulsion (emulsion),
5 parts of water-soluble acrylamide polymer was added, and ordinary Portland cement manufactured by Ube Industries, Ltd. (specific gravity
3.1) was blended in 100 parts to make a polymer cement paint. This paint was evaluated for drying shrinkage, water resistance, and mixing stability using the following methods. [Evaluation method] Drying shrinkage: 300g of paint was placed in a plastic container with a diameter of 5cm and a height of 10cm, and after tamping it 15 times with an iron rod of 20cm in length and 1cm in diameter, the container was covered with a lid and kept at a temperature of 20°C. humidity 65
% for two weeks to cure the paint. 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 This paint was applied to a flexible board with a length of 30 cm and a width of 15 cm to a thickness of 0.2 cm, and 20 Leave to dry for one week in an atmosphere of -65% °C and observe changes in appearance such as cracks. Water resistance: Apply the paint to a peelable steel plate coated with silicone resin so that a film with a wall thickness of 0.2 cm is obtained, leave it at 20℃ for one day to air dry, and then remove it from the peelable steel plate. Peel off the film and remove this film for 20 minutes.
A film was obtained by curing in a room at ℃ for 10 days. Cut this film into 5 cm x 5 cm, measure the mass, and then submerge it in water.
After soaking for 168 hours, the mass was measured immediately after taking it out.
Calculate the water absorption rate using the formula below. Water absorption rate (%) = Paint film mass after immersion - Paint film mass before immersion /
Coating film weight before dipping × 100 Mixing stability: When a water-soluble acrylamide polymer is mixed into an aqueous resin emulsion, and cement and heavy calcium carbonate are further blended, if it exists stably, it will be ○, but it will not fail due to aggregation etc. Once it stabilizes.

[Table] Example 2, Comparative Examples 1-2 Table 1 shows the amount of water-soluble acrylamide polymer added
A polymer cement paint was prepared and evaluated in the same manner as in Example 1 except for the changes shown in . The results are shown in the same table. Example 3, Comparative Examples 3 to 4 Polymer cement paints were prepared and evaluated in the same manner as in Example 1, except that water-soluble acrylamide polymers or methacrylamide polymers produced by the polymerization method shown in Table 2 were used. The results are shown in Table 3. Example 4, Comparative Example 5 Example 1 except that a water-soluble acrylamide polymer obtained by polymerization using the monomers shown in Table 2 was used.
A polymer cement paint was prepared and evaluated in the same manner as described above. The results are shown in Table 4.

【table】

【table】

[Table] Examples 5 to 6 Polymer cement paints were prepared in the same manner as in Example 1, except that the blending ratios of Portland cement and silica sand were changed as shown in Table 5, and evaluated in the same manner as in Example 1. The results are shown in the same table.

[Table] Examples 7-8, Comparative Examples 6-7 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. Polymer cement was prepared by blending water-soluble acrylamide and ordinary Portland cement in the proportions shown in Table 7 with 100 parts of this emulsion. This was evaluated in the same manner as in Example 1 (Example 6,
Comparative Example 6). In addition, cured products obtained by heating the polymer cement paint at 50° C. and forcing drying (Example 7, Comparative Example 7) instead of natural drying were also evaluated. The results are shown in Table 7. In Table 6, AAamide is acrylamide,
MAA is methacrylic acid and 2EHA is 2-ethylhexyl acrylate.

【table】

【table】

Claims (1)

[Scope of Claims] 1 (A) Component: Resin aqueous dispersion (B) Component: Hydraulic cement (C) Component: Water-soluble acrylamide polymer or methacrylamide polymer with a molecular weight of 1,000 to 500,000 The aqueous solution of (A) above The hydraulic cement of (B) is in a proportion of 50 to 3500 parts by weight per 100 parts by weight of the solid content of the resin in the dispersion, and the hydraulic cement of component (B) is 100 parts by weight.
A polymer cement composition comprising 0.2 to 10 parts by weight of water-soluble acrylamide polymer or methacrylamide polymer as component (C) based on the weight part.