JPH0361826B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for repairing cement tiles and factory floors. [Prior art and its problems] Painted cement tiles in which the surface of a cement tile is undercoated with a urethane paint containing cement or an acrylic urethane paint, and the surface is then overcoated with these paints, and epoxy resins containing silica sand. A factory floor is known in which the paint is applied to a floor formed by curing the paint. The top coat layer of these paints is applied to waterproof cement tiles and floors.
No. 53-73231, No. 55-51782, No. 50-67832,
Special Publication No. 52-48618). On these painted cement tiles and factory floors,
When the surface coating layer is damaged, it is necessary to repair it in order to extend the life of the house and floor. Conventionally, for this repair, an aqueous resin dispersion such as a styrene/acrylic acid lower alkyl ester copolymer, a vinyl acetate/acrylic acid lower alkyl ester copolymer, etc., or an aqueous resin dispersion such as ordinary Portland cement, silica sand, etc. A resin mortar mixed with fine aggregate is applied to the damaged area, dried, and, if necessary, top coated with the aqueous resin dispersion for repair. However, the aqueous resin dispersion or resin mortar for repairing damaged parts has weak adhesion to tiles and factory floor bases, and has the disadvantage that the period from repair to next repair is short. Furthermore, when the base coat film is a urethane resin film, it is not possible to obtain a repair film with practical adhesive strength using the resin aqueous dispersion or resin mortar, and it is necessary to place the damaged painted cement tile on a new painted cement tile. The reality is that it is changing. In order to make repairs more reliable, we use an acrylic urethane resin layer for the top coat layer of painted cement tiles and factory floors, and mix ordinary Portland cement and fine aggregate with cationic SBR latex, which has excellent compatibility with cement, as the repair liquid. It was proposed to use a resin mortar made of This resin mortar provides a coating film with excellent adhesive strength to urethane resin coatings, but this is only possible in seasons with small temperature differences such as spring and autumn, and only in seasons with large temperature differences such as summer and winter. It cannot be said that it is practically sufficient depending on the season. [Specific means for solving the problem] The present invention uses an aqueous resin dispersion in which a hydrazine derivative is blended with an aqueous dispersion of an acrylic copolymer containing a carbonyl group as a repair solution for roof tiles, floors, etc. To provide a repair method that provides a coating film with good adhesion to tiles and floors without being affected. [Structure of the Invention] The present invention applies the following components (A) and (B) to the scratched surface of a top coat resin layer selected from urethane resins, acrylic resins, and epoxy resins for painted tiles, factory floors, decorative walls, etc. This invention provides a repair method characterized by forming a coating film of crosslinked resin by applying an aqueous dispersion of room-temperature crosslinkable acrylic resin containing component () and drying. (A) An acrylic copolymer containing a carbonyl group (B) A hydrazine derivative having at least two hydrazine residues. (Adhesive material) The adherend material to which the repair liquid is applied to the wound surface includes urethane resin (including acrylic and urethane resin),
Painted cement tiles with acrylic resin or epoxy resin coatings as the top coat layer, factory floors,
A decorative wall can be provided. (Repair Liquid) The repair liquid is an aqueous dispersion of room-temperature crosslinkable acrylic resin containing the following components (A) and (B). (A) An acrylic copolymer containing a carbonyl group (B) A hydrazine derivative having at least two hydrazine residues. 70% by weight or less of the component (A) in this repair solution is a non-crosslinkable resin aqueous dispersion, such as n-butyl acrylate copolymer, vinyl acetate/ethyl acrylate copolymer, vinyl chloride/acrylic acid copolymer, etc. It may be replaced by an aqueous emulsion such as a polymer. The resin aqueous dispersion consisting of the above components (A) and (B) is disclosed in JP-A Nos. 54-110248, 57-3850, and 58-
It is described in Publication No. 96643. Specifically, the aqueous emulsion of the carbonyl group-containing acrylic copolymer as component (A) is selected from (a) methyl methacrylate, vinyl aromatic compound, tert-butyl acrylate, vinyl halide, and ethylene. (b) a monomer selected from acrylic or methacrylic esters of alcohols having 2 to 16 carbon atoms, methyl acrylate, vinyl esters and 1,3-dienes; mass 25~
(c) 0.1 to 20% by weight of a carbonyl group-containing monomer having at least one aldo or keto group and one polymerizable double bond in the molecule, and
(d) Obtained by emulsion polymerization of a monomer consisting of 0 to 10% by weight of an unsaturated carboxylic acid monomer (see the aforementioned publications). As the monomer (a), methyl methacrylate,
Monomers selected from vinyl aromatic compounds (e.g., styrene, etc.), tert-butyl acrylate, vinyl halides (e.g., vinyl chloride, vinylidene chloride, etc.), and ethylene are used, and the monomer (a The copolymerization ratio of ) is based on the total monomers,
It is usually 10 to 75% by weight, preferably 30 to 70% by weight. Two or more types of monomer (a) can be used in combination. Monomer (a) acts to impart hardness to the coating film of the composition of the present invention. Monomers (b) include acrylic or methacrylic esters of alcohols having 2 to 16 carbon atoms, methyl acrylate, vinyl esters (e.g. vinyl acetate, vinyl propionate, etc.);
and 1,3-dienes (e.g. butadiene, etc.)
The proportion of copolymerization of monomer (b) in emulsion polymerization is usually the same as that of all monomers.
25-90% by weight, preferably 30-70% by weight.
Two or more types of monomer (b) can also be used in combination. monomer
(b) acts to impart flexibility to the coating film. As the monomer (c), a carbonyl group-containing monomer having at least one aldo group or keto group and one polymerizable double bond in the molecule is used.
In addition, ester bond

[Formula] or carboxyl base

Compounds having only [Formula] are not included in this monomer (c). Specific examples of monomer (c) include acrolein, diacetone acrylamide,
Formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g. vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.) General formula (In the formula, R ¹ is H or CH ₃ , R ² is H or an alkyl group having 1 to 3 carbon atoms, R ³ is an alkyl group having 1 to 3 carbon atoms, R ⁴ is 1 to 4 Acrylic (or methacrylic)oxyalkylpropanal, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-hydroxypropyl acrylate-acetylacetate, butanediol-
Examples include 1,4-acrylate-acetylacetate. Particularly preferred are diacetone acrylamide, acrolein and vinyl methyl ketone. The copolymerization ratio of monomer (c) in emulsion polymerization is usually 0.1 to 20% by weight, preferably 1 to 7% by weight, based on the total monomers. Monomer (c) acts to provide a carbonyl group (that is, an aldo group or a keto group) to the carbonyl group-containing copolymer, and the carbonyl group reacts with the organic hydrazine derivative to form a crosslinked structure. This contributes to improving the physical properties of the coating film, particularly the water resistance, chemical resistance, blocking resistance, etc. of the coating film. Examples of the monomer (d) include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid,
Examples include unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, and citraconic acid, acrylamide, methacrylamide, and N-methylolmethacrylamide, and two or more monomers (d) may be used in combination. As described below, particularly preferred monomer (d) is itaconic acid, itaconic acid and acrylic acid, itaconic acid and methacrylic acid, or itaconic acid, acrylic acid, and methacrylic acid. The copolymerization ratio of monomer (d) is usually 0 to
10% by weight, preferably 0.5-5% by weight, more preferably 0.8-2.5% by weight. In order to obtain a room temperature crosslinkable carbonyl group-containing copolymer dispersion of component (A), at least the above (a) to
The monomers consisting of each monomer (d) are emulsion polymerized, and in the emulsion polymerization, these monomers (a) to (d) are
In addition to these monomers, it is also possible to copolymerize other monomers. Other monomers that can be copolymerized include, for example, butanediol diacrylate, butanediol monoacrylate, acrylonitrile, methacrylonitrile, various unsaturated acid amides, and N of unsaturated acid amides.
-alkyl and/or N-alkylol derivatives (eg, acrylamide, N-methylacrylamide, N-isobutylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, etc.). The emulsion polymerization itself for obtaining the aqueous dispersion of the carboxyl group-containing copolymer of component (A) is well known to those skilled in the art. Examples of emulsifiers used in the emulsion polymerization include anionic surfactants such as alkyl sulfates, alkylbenzene sulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phenol ether sulfates, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl ethers. Examples include nonionic surfactants such as oxyethylene alkyl phenol ether, ethylene oxide propylene oxide block copolymer, and sorbitan derivatives. As described below, particularly preferred emulsifiers are alkyl sulfates, alkyl sulfonates, alkyl benzene sulfonates, or combinations of these surfactants with polyoxyethylene alkyl phenol ether sulfate. In addition, as a polymerization initiator in emulsion polymerization,
Examples include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, organic peroxides such as benzoyl peroxide, cumene hydroperoxide, and tertiary butyl hydroperoxide, and azobisisobutyronitrile. . Particularly preferred are water-soluble initiators and resox-type initiators. Next, as an organic hydrazine derivative having at least two hydrazine residues, for example, 2 to
Mention may be made of dihydrazides of dicarboxylic acids containing 10, especially 4 to 6, carbon atoms. That is,
Examples include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, and isophthalic acid dihydrazide. Also, aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms,
For example, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-1,3-dihydrazine
Examples include 1,4-dihydrazine. Particularly preferred organic hydrazine derivatives are adipic acid dihydrazide, isophthalic acid dihydrazide, and sebacic acid dihydrazide. This organic hydrazine derivative of component (B) is cross-linked by hydrogen bonding between the carbonyl group of component (A) and the hydrazine group of component (B) when the solvent (e.g. water) evaporates to form a coating film. form a polymer. It is assumed that the formation of this crosslinked polymer is a factor in improving the heat resistance and tensile strength of the resulting coating film. This organic hydrazine derivative as component (B) is consumed at a rate of 0.02 to 1 mole per mole of carbonyl group (total of aldo group and keto group) of component (A) in the above hydration reaction. The amount to be added is determined taking this into account. If the amount of component (B) is small, the effect of improving the adhesive strength to the adherend and the strength of the coating film will be small. This room-temperature crosslinking emulsion is made by blending the organic hydrazine derivative (B) with the carbonyl group-containing acrylic copolymer emulsion (A).
Acronal YJ- from Yuka Verdice Co., Ltd.
It is sold under the product names 2715D, YJ-2720D, and YJ-2740D. This repair solution may contain a small amount of a hardening accelerator such as zinc sulfate, manganese sulfate, zinc, manganese, aqueous acetate of cobalt or lead, nitrate of cobalt, zinc nitrite, and lead nitrite. When using this repair solution as a repair solution for painted Sento tiles, the resin solid content of the resin emulsion should be 100%
50 to 1000 parts by weight of Portland cement
It is preferable to mix 50 to 2000 parts by weight of fine aggregate such as silica sand in terms of improving adhesion to painted cement tiles, drying the repair solution, and thickening the coating material. Instead of the above-mentioned Portland cement, white cement, early strength cement, ultra early strength cement, etc., and mixed cements such as blast furnace cement, silica cement, fly ash cement, etc. can also be used. This repair solution further contains pigments; extender pigments such as calcium carbonate, talc, clay, mica powder, and barite; potassium, sodium, or ammonium salts of condensed phosphoric acid such as hexametaphosphoric acid; sodium or ammonium salts of polyacrylic acid. ; Usual anionic or nonionic surfactants; Dispersants such as methylcellulose, ethylcellulose, propylcellulose, carboxymethylcellulose, polyvinyl alcohol; Various components such as plasticizers and thickeners; petroleum resins, rosin, terpenes, etc.; An adhesive such as a phenol copolymer can be blended. The repair liquid is applied to the damaged surface of the adherend using a brush, trowel, spray, roll, or the like. If necessary, an acrylic resin topcoat or a urethane resin topcoat is applied onto the coating film formed by the repair solution to form a top coat layer with good gloss. (Effect) The crosslinked coating film formed by the repair liquid used in the present invention is
It has excellent adhesion not only to urethane resins, acrylic resins, and epoxy resins, but also to cement products, and because it is crosslinked, it has excellent tensile strength and creep, so it has the advantage that its performance is not affected by temperature. Hereinafter, the present invention will be further explained in detail by giving Examples and Comparative Examples. Parts and percentages in these examples are by weight unless otherwise specified. Production Example of Acrylic Copolymer Aqueous Emulsion Example 1 The following materials were charged into a reaction vessel equipped with a temperature controller, an anchor stirrer, a reflux condenser, a supply vessel, a thermometer, and a nitrogen inlet tube. 200 parts of water 10 parts of a 35% aqueous solution of the sodium salt of the sulfuric acid half ester of p-phenylphenol (anionic emulsifier) reacted with 20 moles of ethylene oxide 1.5 parts of the sodium alkyl sulfate salt Separately, prepare the following mixture as a feed. did. Water 200 parts 35% aqueous solution of the above anionic emulsifier 20 parts Styrene 150 parts Acrylic acid 2-ethylenehexyl ester
170 parts Methyl methacrylate 140 parts Diacetone diacrylamide 20 parts Acrylic acid 10 parts Acrylamide 10 parts In addition, a solution of 2.5 parts of potassium persulfate dissolved in 85 parts of water was prepared as a feed. After purging the inside of the reaction vessel containing the above-mentioned charges with nitrogen gas, 10% of the feed was added and heated to 90°C, and then 10% of the feed was injected. 90℃
The feed and the remainder of the feed were uniformly fed into the reactor little by little over a period of 3 to 3.5 hours while stirring under heating. After the supply was completed, the reaction was continued at 90°C for another 1.5 hours with stirring, and then the inside of the reactor was cooled to room temperature. Aqueous ammonia was added to the resulting dispersion to adjust the pH to 7 to 8 to obtain an aqueous copolymer dispersion with a solid content of 50%. Examples 2 to 4 An aqueous dispersion of an acrylic copolymer was obtained in the same manner as in Example 1, except that the component ratio of the vinyl monomer was changed as shown in Table 1.

【table】

[Table] Examples 1 to 6, Comparative Examples 1 to 3 Repair liquids having the compositions shown in Table 2 were prepared. Apply this repair solution to a surface of the detonation plate, which has (a) a urethane resin film, (b) an epoxy resin film, and (c) an acrylic resin film as a top coat layer, at a thickness of 2 mm.
After applying the coating to obtain a coating film of
Thereafter, after drying at 20°C for 48 hours, the adhesive strength of the coating film was measured according to the method of JIS A-6910. The results are shown in Table 2. (1) After standard curing: Measure immediately after curing at 20℃ for 7 days. (2) After soaking in water: After soaking the sample in water for 10 days. (3) After hot water test: One cycle consists of soaking the sample in hot water at 60°C for 2 hours, taking it out and drying it at 80°C for 1 hour, and repeating this cycle 10 times. (4) After cold cycle: immersed in 20℃ water for 16 hours, frozen at -20℃, kept for 4 hours, then 80℃
One cycle is keeping dry for 4 hours at 10
After repeating.

【table】

Claims (1)

[Claims] 1. The following component (A) is added to the surface of a resin layer selected from urethane resin, acrylic resin, and epoxy resin.
(B) A repair method characterized by applying an aqueous dispersion of cross-linked acrylic resin at room temperature and drying it to form a coating film of cross-linked resin. (A) Acrylic resin containing a carbonyl group Polymer (B) A hydrazine derivative having at least two hydrazine residues. 2. The repair method according to claim 1, wherein component (B) is blended in a proportion of 0.02 to 1 mole per mole of galvonyl group in component (A).