JPH0140065B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an emulsion resin composition that can be applied to the surface of a structure to form a coating film with excellent selective water vapor permeability and waterproof properties, and in particular, relates to an emulsion resin composition that can be applied to the surface of a structure to form a coating film with excellent water vapor selective permeability and waterproof properties. The present invention relates to an emulsion resin composition that has permeability and carbon dioxide barrier properties and can provide a coating layer with excellent weather resistance and extensibility. [Conventional technologies and their problems] In general, the outer walls of structures such as residences have the role of controlling the external environment and indoor environment, and are usually (1) waterproof (water impermeable) (2) It is required to have various properties such as water vapor permeability (3) carbon dioxide gas barrier (4) aesthetic appeal. Also,
In connection with the application of such a coating layer as a surface material, it is further important that it is a coating forming material with good stain resistance, resistance to discoloration and fading over time, and various surface finishing properties. be. In response to such practical demands, in recent years, a coating film waterproofing method using an emulsion of an acrylate resin having a waterproof function has been widely adopted even in the painting of the exterior walls of structures. Generally speaking, in the cold season, condensed water intrudes into the walls of structural concrete and freezes, causing destruction of the concrete. Therefore, it is an important technical matter to prevent water from penetrating into the concrete, and from this point of view Regarding the coating film waterproofing materials used in the coating film waterproofing method,
An emulsion made of acrylate synthetic resin, which has particularly excellent waterproof properties, was used. Such synthetic resin emulsion coating materials that emphasize waterproofing usually have low water vapor permeability, and indoor water vapor that has penetrated into the concrete remains without being released and becomes internal condensation water, which increases the thermal conductivity of the concrete. In other words, the phenomenon of a decrease in heat insulation properties was unavoidable. Therefore, in winter, this can lead to unfavorable phenomena such as dew condensation on indoor wall surfaces and the growth of mold, as well as high heating costs.Especially in cold regions, condensed water inside the concrete can freeze. As a result, frost damage such as destruction of concrete is occurring. In addition, inorganic polymer-based water-repellent coating film waterproofing materials that simply focus on water vapor permeability function have a coating that lacks flexibility and waterproofness, and furthermore, has low carbon dioxide gas barrier properties, so it cannot be used for concrete structures. Its deterioration prevention function is extremely weak, which is a practical problem. Therefore, the purpose of the present invention is to improve the above-mentioned drawbacks of conventional synthetic resin emulsions and inorganic polymer-based water-repellent coating materials, and to achieve the above-mentioned desired performances (1) to (1) required for exterior coatings. The object of the present invention is to provide a coating material for the exterior walls of concrete structures that is highly desirable for practical purposes. [Means for Solving the Problems] As a result of extensive research into coating materials for coating film formation that achieve the above objectives, the present inventors have developed an emulsion resin composition that can provide a practically extremely desirable coating film. Developed coating material. That is, in the present invention, the polymerizable vinyl monomer is combined with 60 to 85% by weight of a nonionic surfactant selected from the group consisting of polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, and polyoxyalkylene fatty acid ester. % and 15-40% by weight of a water-soluble or water-dispersible polyalkylene glycol.
A coating material comprising a polymer aqueous emulsion pigment obtained by polymerization in an aqueous polymerization system containing % by weight, and a waterproof coating film obtained by adjusting the pigment volume concentration of the coating material to 40% or less. An emulsion resin composition is provided. The composition of the present invention uses a resin emulsion formed by polymerizing a polymerizable vinyl monomer in the presence of a mixture emulsifier system containing a specific nonionic surfactant and an aqueous polyoxyalkylene in a specific range of proportions. The technical feature is that the pigment volume concentration is 40% or less. Therefore, the nonionic surfactants used in the present invention are polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenyl ethers, and polyoxyalkylene fatty acid esters, and compounds having these polyoxyalkylenes and alkyl groups. The alkyl group in has 4 to 20 carbon atoms, preferably 8 to 15 carbon atoms.
The polyoxyalkylene is a lipophilic moiety, and the polyoxyalkylene is a water-philic moiety, and in particular, polyoxyalkylene is a water-philic moiety, and is particularly composed of polyethylene oxide or ethylene oxide as a main component, and contains a small amount of propylene oxide or butylene oxide, with an average number of added moles of 3 to 3. 80, preferably
It is a nonionic emulsifier with a strong water affinity of 20 to 50. These nonionic surfactants may be used alone or in combination of two or more. In the composition of the present invention, it is important that the polyalkylene glycol that forms an emulsifier system together with the nonionic surfactant in the aqueous medium polymerization system in which the vinyl monomer is polymerized is water-soluble or water-dispersible. Generally, polyalkylene glycols have an average molecular weight of 800 to 6,000, preferably 2,000 to 4,000, and particularly preferred are polyethylene glycols with a degree of polymerization of 40 to 75. It is important that the emulsifier system formed from the above-mentioned nonionic surfactant and polyalkylene glycol is composed of 60 to 85% by weight of the former and 15 to 40% by weight of the latter; If the amount is less than 15% by weight, a synergistic effect of the combination of emulsifiers cannot be obtained, and if it exceeds 40% by weight, aggregates of polymer particles are likely to be formed in the emulsion polymerization process, and the resulting emulsion may As a result, the physical properties such as water resistance of the coating film formed are inferior, so it is not preferred in practice. The desired mixing range for glycols is 20
~30% by weight. In forming an emulsion of the composition of the present invention, it is difficult to form a desirable emulsifier system using anything other than the nonionic surfactant and polyalkylene glycol as described above, and the ratio of the combination of both components exceeds the above range. This is not preferable because a coating resin emulsion suitable for forming the waterproof coating film of the present invention cannot be obtained. Furthermore, in the present invention, it is important that such an emulsifier system is present in the aqueous polymerization system in an amount of 1 to 8% by weight to polymerize the vinyl monomer, and if the vinyl monomer is polymerized outside this range, the emulsion resin composition is not desirable. For example, if the amount is less than 1% by weight, the film formed will not exhibit favorable moisture permeability, and if it exceeds 8% by weight, a good emulsion may not be obtained.
Even if it is obtained, it is disadvantageous because the water resistance of the formed coating film is extremely poor. The vinyl monomers to be polymerized in such a polymerization system are not particularly limited as long as they are vinyl monomers that can be emulsion polymerized, but examples include methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic acid. Esters of acrylic acid or methacrylic acid such as 2-ethylhexyl and methyl methacrylate; halogen molds such as vinyl bromide, vinyl chloride, and vinylidene chloride; vinyl esters such as vinyl acetate and vinyl propionate; styrene, Vinyl aromatic monomers such as vinyltoluene;
Monoolefins and conjugated diolefins such as ethylene, propylene, butadiene; α,β-unsaturated acid amides such as acrylonitrile and acrylamide; acrylic acid, methacrylic acid, itaconic acid,
α,β-unsaturated carboxylic acids such as maleic acid and fumaric acid; vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropylmethoxysilane, γ- Vinyl alkoxysilanes such as glycidoxypropylmethyldiethoxysilane and glycidoxyalkoxysilanes are preferably used. These monomers can be used alone or in combination of two or more. Among them, when vinyl alkoxysilanes or glycidoxyalkoxysilanes are used together in an amount of 0.1 to 10% by weight, preferably 1 to 5% by weight, based on other vinyl monomers, the water vapor permeability of the coating film is improved, and the coating properties are improved. Its use is highly desirable since it provides desirable performance improvements such as improved adhesion of the film to the inorganic substrate, improved non-stick properties of the coating, and improved hydrophobicity of the coating. As the polymerization initiator used in the polymerization of the present invention, a conventional polymerization initiator or polymerization initiator system can be conveniently used. Polymerization initiators that are advantageously used industrially include, for example, hydrogen peroxide, potassium persulfate, ammonium persulfate, etc., but if necessary, sodium bisulfite, ascorbic acid, tartaric acid, sodium thiosulfate, etc. A reducing agent can be used in combination. Polymerization can be easily carried out by a conventional polymerization method in a polymerization system using water as a medium. The composition used in the coating material of the present invention is prepared by adding a pigment to the aqueous vinyl resin emulsion produced as described above. Examples of color pigments to be mixed in the composition of the present invention include titanium oxide, zinc white, iron oxide, yellow lead, chromium oxide, cadmium yellow, cadmium red, molybdenum red, cobalt purple, cobalt green, and cobalt blue. , ultramarine, navy blue, copper phthalocyanine blue, copper phthalocyanine green, permanent red 4R,
Examples include Watching Red and First Yellow 10G. Examples of extender pigments include kaolin clay, calcined clay, talc, wollastonite, organic bentonite, carbon black, white carbon, aluminum oxide, calcium carbonate, barium sulfate, mica, and polyethylene powder. These may be used alone or in combination of two or more. In the composition of the present invention, a coating material composition is prepared by uniformly mixing such a pigment with the aqueous vinyl polymer emulsion prepared as described above. It is important that the pigment volume concentration (PVC) of the emulsion resin composition prepared is 40% or less. If this PVC exceeds 40%, the desired water vapor permeability,
This is inconvenient because it is not possible to obtain a coating film that has various properties such as carbon dioxide gas barrier properties and waterproof properties. Preferred PVC in the composition is 10-35%. In preparing the compositions of the invention, water can be added if desired. The above-mentioned PVC in the present invention is determined, for example, by the following formula. PVC = [ 〓 ⁱ (Wpi/Ppi)] / [ 〓 ⁱ (Wpi/Ppi)] + [ 〓 ⁱ (Wbi/Pbi)] × 100 The symbols in the formula are as follows. Wpi: Weight % of i type pigment Wbi: Weight % of i type binder polymer Ppi: Specific gravity of i type pigment Pbi: Specific gravity of i type emulsion polymer Various additives that are added to materials in small amounts, such as viscosity modifiers, surfactants, antifoaming agents, preservatives, fungicides, and antiblocking agents, can be used. Advantageously used viscosity modifiers are, for example, methylcellulose, hydroxyethylcellulose, sodium polyacrylate, surfactants are sodium polyacrylate, sodium polyacrylate, etc.
sodium hexametaphosphate, etc., and
The antifoaming agent is a fatty acid metal soap, an aliphatic higher alcohol, a silicone type, etc., and each agent is usually used in a small amount of about 3% by weight or less based on the solid content of the resin. Furthermore, water repellents and anti-blocking agents that are added as necessary include, for example,
Commonly known fluorine-based, polyethylene wax-based, zirconium-based, palladium-based and paraffin wax-based waxes are used, and they are usually used in an amount of 5 parts by weight based on 100 parts by weight of the resin solid content of the emulsion.
Approximately 25% by weight is added. It is also possible to add small amounts of preservatives and fungicides. The coating material composition of the present invention usually has a yield of 1,000 to 50,000 cps.
(BH type viscometer, 60rpm, rotor No.7, 20℃)
It can be easily applied to the surface of structural materials using various application means such as brushes, air sprays, and rollers. [Function] The emulsion composition of the present invention has excellent water vapor permeability and water impermeability, as well as high carbon dioxide gas barrier properties, so it is useful as a surface layer material for various structural materials, and its practical use The value is extremely high. [Example] Hereinafter, the features of the present invention will be explained in more detail with reference to specific examples. In addition, the measurement methods and evaluation criteria for various physical properties of coating films formed with various coating materials in specific examples are as follows. (1) Waterproofness: JIS A6910 Water permeability test for multi-layer finish coating materials 51.10
Measure according to. The practically desirable water permeation depth in this method is 0.5 ml or less. (2) Water vapor permeability: Measured according to JIS Z0208 Moisture permeability test for moisture-proof packaging materials - Method A. The moisture permeability practically evaluated in this method is 150 g/m ² ·24 hr or more. (3) Carbon dioxide barrier property: P/C = 0.5 with 15% by weight polymer cement
A 1/3 mortar measuring 15 x 15 x 45 cm, which had been completely repaired to a mm thickness, was coated with a coating material to a thickness of 70 μm, and was placed in a neutralization tester at a carbon dioxide concentration of 5% by volume, a temperature of 20°C, and a humidity of 65%. The cut surface was left to stand for one month, and a phenolphthalein solution was sprayed onto the cut surface, and the depth of the surface layer that did not change color was measured. The carbon dioxide gas barrier property that is practically evaluated is at a depth of 1.5 mm or less from the surface. Example 1 Acrylic acid n-
Using 44.2 parts by weight of butyl, 4.8 parts by weight of methyl methacrylate, and 1.0 parts by weight of methacrylic acid, 43.9 parts by weight of water in the polymerization tank, and 3.1 parts by weight of polyoxyethylene lauryl ether with an addition mole number of ethylene oxide of about 40 as an emulsifier. using a combination of 1.0 parts by weight of polyethylene glycol with an average molecular weight of 3000, and 1.0 parts by weight of ammonium persulfate as a polymerization initiator system.
% aqueous solution 1.0 parts by weight and sodium bisulfite 10
Using 1.0 parts by weight of the % aqueous solution, polymerization and aging reactions were carried out at a temperature of about 70° C. for about 4 hours to prepare an aqueous polymer emulsion. To 60.0 parts by weight of the obtained emulsion were added 0.7 parts by weight of sodium polyacrylate, 0.3 parts by weight of hydroxyethyl cellulose, 12.0 parts by weight of titanium oxide, 0.1 parts by weight of aqueous ammonia, 0.2 parts by weight of preservative, 1.0 parts by weight of ethylene glycol, and 25.0 parts by weight of water. and 0.5 parts by weight of fatty acid metal soap were added and thoroughly stirred to prepare a coating material composition containing 8.1% PVC. The prepared composition was sprayed onto various test plates using an air spray gun to form a coating film with a dry film thickness of 70 μm. After maintaining each of the test specimens thus prepared under standard conditions (20° C., RH 60%) for 7 days, the performance of each coating film was measured according to each of the test methods described above. As a result, the water permeability of the coating film was 0.2 cc, the moisture permeability was 380 g/m ² ·24 hr, no carbon dioxide permeation was observed, and its barrier properties were perfect. Examples 2 to 3 and Comparative Examples 1 to 2 Various PVC coating compositions were prepared using various amounts of the aqueous polymer emulsion of Example 1 and varying the type and amount of pigment added thereto and the amount of additional water. death,
The same measurement test as in Example 1 was conducted. The changing conditions and measurement results are summarized in Table 1 below.
For reference, those in Example 1 are also listed.

[Table] From the above table, the compositions of the present invention (Examples 1 to 3) having a PVC of 40 or less are superior to the compositions of Comparative Examples 1 to 2 having a PVC exceeding 40. It is understandable that Examples 4 to 7 and Comparative Examples 3 to 4 Acrylic acid 2-
15.7 parts by weight of ethylhexyl, 1.0 parts by weight of methacrylic acid, and 33.3 parts by weight of styrene were used as an emulsifier system, which was present in an amount of 4.1% by weight in the aqueous polymerization reaction system. POE-LE)
Various aqueous polymer emulsions were produced in substantially the same manner as in Example 1, except that a combination of PEG and polyethylene glycol (PEG) having an average molecular weight of 3000 was used, and the proportions were varied. Next, the same coating test as in Example 1 was conducted on each emulsion resin composition prepared by mixing titanium oxide as a pigment into the obtained emulsion to form PVC19.2. The results are shown in the table below.

[Table] As is clear from the above table, the composition of the present invention has
While the compositions of Comparative Examples 3 and 4 outside the present invention have moisture permeability that satisfies practical evaluation criteria, that is, water vapor permeability, carbon dioxide gas barrier property, and _waterproof property, It can be seen that the insulation properties are poor and it is not suitable as an outer wall of a structure. Examples 8 to 9 and Comparative Examples 5 to 6 In Example 5, polymerization was carried out by varying the concentration of the emulsifier system of POE-LE and PEG (weight ratio 75/25) present in the aqueous polymerization reaction system. Various coating resin compositions were prepared in exactly the same manner except for the above. The test results for the performance of each coating are shown in the table below.

[Table] From the results in the above table, it can be understood that the vinyl polymer emulsion used in the composition of the present invention is not desirable for coating materials if the concentration of the emulsifier in the polymerization is too low or too high. Examples 10 to 13 As vinyl monomers, 2-ethylhexyl acrylate (2-EHA), methacrylic acid (MAA),
Various copolymer aqueous emulsions were prepared in exactly the same manner as in Example 1, except that various combinations of styrene (St), vinyl acetate (BAc), ethylene (Et), and vinyltris(2-methoxyethoxy)silane (BTS) were used. Furthermore, each coating film-forming composition was prepared, and the physical properties of each coating film were measured. Those measurement results are shown in Section 4 below along with the monomer composition.
Shown in the table.

【table】

Claims (1)

[Scope of Claims] 1 The polymerizable vinyl monomer is a nonionic surfactant selected from the group consisting of polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, and polyoxyalkylene fatty acid ester 60 to 85 % by weight and water-soluble or water-dispersible polyalkylene glycol 15-40% by weight
A coating material comprising a pigment and an aqueous polymer emulsion obtained by polymerization in an aqueous polymerization system containing 1 to 8% by weight of an emulsifier system, wherein the pigment volume concentration of the coating material is 40% or less. A water vapor permeable emulsion resin composition prepared by the method. 2. The composition according to claim 1, wherein the polymerizable vinyl monomer is mainly an acrylic ester monomer or a methacrylic ester monomer. 3. The composition according to claim 1, wherein the polyalkylene glycol is polyethylene glycol. 4. The composition according to claim 1, wherein the pigment volume concentration is 10 to 35%. 5. The composition according to claim 1, wherein the solid content concentration is 30 to 70% by weight.