JP4623707B2 - Quick-drying aqueous coating composition - Google Patents

Description

  The present invention relates to a water-based paint composition, and particularly to a normally dry water-based paint composition having quick drying properties and excellent coating performance including asphalt adhesion.

  Conventionally, solvent-type paints have been generally used as the ever-drying paints used for building exterior and interior applications, floor applications, road applications, and the like. Solvent type paints have no problem in terms of performance, but have solvent toxicity or flammability problems. Especially in the above applications, it is impossible to recover the solvent used. Eventually, it volatilizes in the atmosphere, causing wasteful use of earth resources and environmental pollution problems.

Therefore, in recent years, an aqueous type paint mainly composed of emulsion is being used as an alternative technique. Water-based paints are much more preferable than organic solvent-type paints in terms of safety and environment, but they require a long time for drying, which is a major problem in actual painting work. Especially in the case of external coating, paints are often exposed to rain, snow, wind, dust, and other pollutants during drying, and the coating film is often damaged. . Also, water-based paints are generally delayed in drying properties under environmental conditions, particularly at low temperatures and high humidity, and there is a need for paints that always have high drying properties regardless of environmental conditions. . Needless to say, the drying property has a contradictory relationship with the stability of the coating material, and it is necessary to improve the drying property while ensuring the stability of the coating material.
Japanese Patent Application No. 2003-337284

  As a technique for satisfying the above-mentioned problems, the present inventors have already proposed Patent Document 1. That is, (1) an aqueous dispersion base resin obtained by polymerizing an α, β-ethylenically unsaturated monomer containing 50% by weight or more of acrylic acid or methacrylic acid ester, and (2) an allyl group-containing secondary or This is a technique relating to an amine polymer obtained by polymerizing a tertiary amine, and a quick-drying aqueous coating composition containing an excess amount of a volatile base as an essential component from the amino groups of (3) and (2). As described in the specification of the present technology, the dryness of the minute order is achieved as intended, but it is necessary to further improve the adhesion to the asphalt when applied to the base material, particularly road applications. . There is also a need to further improve the stability of the paint.

  For these reasons, the present inventors have focused on improving the above-mentioned problems and found that the target is achieved by controlling the average particle size and particle size distribution of the aqueous dispersion type base resin. The present invention has been completed. That is, the present invention is (1) an aqueous dispersion resin obtained by polymerizing an α, β-ethylenically unsaturated monomer containing 50% by weight or more of an acrylic acid ester or methacrylic acid ester, and having an average particle size of 50 to A base resin having a standard deviation of 200 nm or less in particle size, (2) an amine polymer obtained by polymerizing an allyl group-containing secondary or tertiary amine, and (3) an amino group of (2) The present invention relates to a quick-drying aqueous coating composition containing an excessive amount of a volatile base as an essential component.

    The water-based coating composition of the present invention is a normally-dry type and extremely quick-drying property, and has excellent coating film properties. Therefore, it can be used mainly for building exterior and interior applications, floor applications, iron member applications or road applications, and particularly has excellent asphalt adhesion, and therefore provides a composition suitable for road applications.

  The quick-drying aqueous coating composition of the present invention will be described in detail below.

[1] About Aqueous Dispersion Base Resin The aqueous dispersion base resin is a component as a base resin (binder) of a paint in the present invention. As a typical production method, 50 acrylates or methacrylates are used. A known emulsion polymerization method, suspension polymerization method, method of emulsifying after solution polymerization and the like are used for, but not limited to, α, β-ethylenically unsaturated monomers containing at least wt%. .

  In producing the aqueous dispersion base resin of the present invention, an anionic surfactant and a nonionic surfactant are used in combination in order to obtain a target average particle size and particle size distribution. Examples of anionic surfactants include sodium lauryl sulfate, alkali salts of higher alkyl sulfates such as ammonium, dodecylbenzenesulfonic acid, sodium isopropylbenzenesulfonic acid, alkali salts of alkylarylsulfonic acid such as ammonium, Isopropylnaphthalenesulfonic acid, nonylnaphthalenesulfonic acid, sodium dinonylnaphthalenesulfonic acid, alkali salts of alkylnaphthalenesulfonic acid such as ammonium, nonylphenol sodium polyethoxyethanol sulfate, alkylaryl polyethoxyethanol sulfate such as ammonium or sulfone Alkali salt of acid, polyoxyethylene lauryl ether sulfate or sodium or ammonium salt of sulfonic acid, Aqueous - alkali salt of a carboxyl group-containing copolymer having a balance of hydrophobicity and the like.

  Examples of nonionic surfactants include polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethyne alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl. Ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene derivatives such as polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monostearate, sorbitan monostearate, sorbitan trioleate, Sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene Examples include so-called pluronic type in which polyoxypropylene is block copolymerized, other polyoxyethylene alkylamines, alkylalkanolamides, propenyl groups or other polymerizable unsaturated groups, and reactive emulsifiers containing polyoxyethylene groups. It is done.

  There are two methods for using the surfactant: a method of using the monomer from the time of polymerization, or a method of using it at the time of carrying out water dispersion after polymerization, and either method has no problem. The amount of the surfactant used is preferably 1.5 to 5% by weight based on the total monomers.

  In order to assist the dispersing effect of the surfactant, it is preferable to copolymerize a monomer containing an acid group in the aqueous dispersion base resin of the present invention. For example, acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, 2-acrylamido-2-methylpropanesulfonic acid, propenyl group or other polymerizable groups. Examples thereof include acid group-containing monomers such as reactive emulsifiers containing saturated groups and sulfate ester groups or sulfonic acid groups. The amount used is particularly preferably such that the acid value per resin solids is 0.5 to 40 KOH mg / g.

  For the measurement of the particle diameter of the aqueous dispersion type base resin, a laser diffraction / scattering particle size distribution measuring apparatus can be suitably used, but measurement by other methods is also possible. For example, using a laser diffraction / scattering particle size distribution measuring apparatus LA-910 manufactured by Horiba, Ltd., the average particle diameter and the standard deviation of the particle diameter are obtained from the following mathematical formula 1 which is general in statistical processing.

  As described above, an anionic surfactant and a nonionic surfactant are used in combination, and a monomer having an acid group is introduced into the aqueous dispersion base resin to adjust the particle size and particle size distribution. As a result, the aqueous water-dispersed base resin of the present invention having excellent asphalt adhesion can be obtained. The average particle diameter is 50 to 200 nm, and the standard deviation of the particle diameter is 100 nm or less, but more preferable ranges are 50 to 180 nm and 70 nm or less, respectively. In addition, by using this method, it is possible to sufficiently secure the stability of the paint. When the average particle size and the standard deviation of the particle size are larger than the claims, the permeability of the paint to asphalt is suppressed and the adhesion is lowered. In addition, the coating tends to aggregate over time, and the stability is also lowered.

  The preferred molecular weight of the aqueous dispersion base resin is 5,000 to 500,000. If necessary, the molecular weight can be adjusted by using a chain transfer agent. The Tg of the resin is preferably −10 to 60 ° C. from the viewpoint of coating film formation, but is preferably 15 to 35 ° C. in consideration of the drying property at high temperature and the film forming property at low temperature.

  Except for the monomer containing an acid group, 50% by weight or more of acrylic acid ester or methacrylic acid ester is contained in all monomers. Specific examples of acrylic ester or methacrylic ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl. Methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, heptyl Mekakuri Alkyl ester of acrylic acid or methacrylic acid such as a salt, and further hydroxy group-containing 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4- Examples thereof include hydroxybutyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate and the like, and lactone-modified products thereof.

  Monomers other than acrylic acid esters or methacrylic acid esters can be used within a range not exceeding 50% by weight. For example, vinyl such as styrene, α-methylstyrene, vinyl toluene, vinyl acetate, acrylonitrile, methacrylonitrile, etc. Examples include monomers, amide monomers such as acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, methoxymethyl acrylamide, n-butoxymethyl acrylamide, diacetone acrylamide, and diacetone methacrylamide.

[2] Amine polymer The amine polymer of the present invention is a polymer obtained by polymerizing an allyl group-containing secondary or tertiary amine. The amine polymer of the present invention is basically water-insoluble in a region where no acid coexists or a region where a base is present. Therefore, in a system in which a volatile base such as ammonia or organic amine is present as in the present invention, the aqueous dispersion base resin of the present invention and the amine polymer of the present invention exist independently of each other in a state dispersed in water, Furthermore, since the particle size and particle size distribution of the aqueous dispersion base resin are within a predetermined range, a stable state is ensured. However, when the volatile base is volatilized, the result is that only the aqueous dispersion base resin of the present invention and the amine polymer of the present invention are present in the system, and they start to interact with each other, and the amine polymer of the present invention is insoluble in water. Therefore, the aqueous dispersion base resin is effectively aggregated. Due to this rapid agglomeration, it is possible to achieve a dryness on the order of minutes while being a water-based paint. If it repeats, in the paint composition of the present invention, in the form of paint, it is stable even if an amount of amine polymer necessary and sufficient for aggregation is used, and the volatile base is volatilized in the coating formation process after painting. For the first time, the aqueous dispersion base resin effectively agglomerates, and the dryness on the order of minutes that cannot be obtained by the prior art is achieved.

  Among the amine polymers of the present invention, particularly an amine polymer obtained from an amine having two allyl groups generally has a ring structure as shown in the following chemical formula 1, and its polymer chain is rigid. It is preferable because it functions extremely effectively in the aggregation with the aqueous dispersion base resin.

  In this way, in the present invention, it is possible to provide an ultra-fast drying water-based coating composition that does not exist in the prior art, but also for coloring, the amine polymer of the present invention has only secondary or tertiary amino groups. Since there is no primary amino group, there is no problem.

  Examples of amine polymers used in the present invention include homopolymers of allyl group-containing secondary amines such as diallylamine, methylallylamine, and ethylallylamine, copolymers with other monomers, dimethylallylamine, diethylallylamine, methyl Examples include homopolymers of tertiary amines such as diallylamine and ethyldiallylamine, and copolymers with other monomers. Polymers obtained from diallylamine, methyldiallylamine, ethyldiallylamine, etc. having two allyl groups are particularly preferred. Although there is no limitation in particular about the other monomer to copolymerize, sulfur dioxide is the representative. In the case of a copolymer, the copolymerization amount of an allyl group-containing secondary or tertiary amine is preferably 20% by weight or more.

  The molecular weight of the amine polymer of the present invention is not particularly limited, but is preferably from 500 to 50,000 from the viewpoints of the cohesiveness of the aqueous dispersion base resin, the drying property of the paint, and the stability. In particular, 1000 to 20000, more preferably 1000 to 10,000 are preferable. Moreover, about the usage-amount, 0.1-10 weight part is especially preferable with respect to 100 weight part of aqueous dispersion base resin.

An example of a specific method for producing the amino polymer of the present invention is a method of polymerizing diallylamine or methyldiallylamine hydrochloride in a polar solvent using ammonium persulfate or a water-soluble azo compound as an initiator. Examples of copolymerization with a body include a method of obtaining a 1: 1 alternating copolymer using sulfur dioxide, but are not particularly limited thereto. Specifically available products include PAS-92 and PAS-M-1 manufactured by Nitto Boseki Co., Ltd.
The product is usually supplied in the form of hydrochloride, but as a specific method of use in the present invention, it can be used as it is, and before addition, hydrochloric acid is neutralized with an alkali in advance or an ion exchange resin is used. It is also possible to use it after removing hydrochloric acid or exchanging it with formate, acetate or other organic acid salt. In particular, when the object to be coated is a metal material such as iron or aluminum, formic acid tends to cause rusting and corrosion of the material after coating, but it can be suppressed by the combined use of rust preventives and rust preventive pigments. More preferably, it is used as a salt of an organic acid such as acetic acid. Specifically available products include Nitto Boseki Co., Ltd. PAS-92A. Examples of organic acids other than formic acid and acetic acid include lactic acid, propionic acid, butyric acid, citric acid, malic acid, and the like.

[3] Volatile base The base used in the present invention is not particularly limited as long as it is a volatile base, but ammonia is particularly preferred. For bases other than ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine, dibutylamine, tributylamine and other alkylamines, diethanolamine, diisopropanol Examples include alkanolamines such as amine, triethanolamine, dimethylethanolamine and diethylethanolamine, alkylenepolyamines such as ethylenediamine, propylenediamine, diethylenetriamine and triethylenetetramine, ethyleneimine, pyrrolidine, piperidine, piperazine and morpholine.
Regarding the amount used, a minimum excess amount of volatile base is required with respect to the amino groups of the amine polymer, but in consideration of the drying property and stability of the paint, the excess amount is 2 to 40 times with respect to the amino groups. Is more preferable.

[4] About PH Buffering Agent In the present invention, a buffering agent can be used to ensure the PH stability of the paint. Examples of the buffer include ammonium chloride, sodium acetate, sodium phosphate and the like.

Further, the coating composition of the present invention can contain a pigment for coloring or concealing the resulting coating film. Examples of pigments include titanium oxide, carbon black, black iron oxide, red iron oxide, yellow iron oxide, titanium yellow, other azo, anthraquinone, phthalocyanine color pigments, calcium carbonate, barium sulfate, talc, kaolin, etc. Examples of extender pigments and hollow pigments are not particularly limited.
Applications are not limited to iron members, exteriors, interior wall materials, flow floor materials, road paints, etc., but they can be used widely. Especially in iron members, known anti-rust pigments or anti-rust agents are used to prevent rust. Sodium nitrite or the like can be used in combination.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited thereto. The numbers in Tables 1 to 3 represent parts by weight unless otherwise specified.

[Production of aqueous dispersion base resin]
[Production example]
(1) to (4) shown in Table 1 are charged into a reaction vessel equipped with a thermometer, a condenser, and a stirring device, and the temperature is raised to 80 ° C. After the temperature rise, (5) is charged, and pre-emulsified (6) to (13) are added dropwise over 3 hours. After the completion of the dropwise addition, the reaction is terminated by incubating for 1 hour. Thereafter, the mixture was cooled to 40 ° C. or lower, and (14) was added to obtain aqueous dispersion base resins (A) to (F).

(註 1) Anionic surfactant manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (註 2) Nonionic surfactant manufactured by Kao Corp. (註 3) Laser diffraction / manufactured by Horiba Ltd. Measured using a scattering particle size distribution analyzer LA-910

[Coating and evaluation of paint]
[Examples 1 to 7 and Comparative Examples 1 to 4]
Disperse dispersion was performed for (1) to (7) with the formulations shown in Table 2 and Table 3, and then (8) to (13) were added to prepare each paint.

(Note 4) Pigment dispersant (concentration 40%) manufactured by San Nopco Co., Ltd.
(Note 5) Maruo Calcium Co., Ltd. Super SS
(Note 6) DuPont R-706
(註 7) PAS-92 Nittobo Co., Ltd. diallylamine, hydrochloride salt of copolymer with sulfur dioxide (concentration 20%)
(Note 8) PAS-92A Nittobo Co., Ltd. diallylamine, acetate salt of copolymer with sulfur dioxide (concentration 20%)
(註 9) PAS-92B For the production method, PAS-92, which is a hydrochloride salt of a copolymer with diallylamine and sulfur dioxide, manufactured by Nitto Boseki Co., Ltd., is treated with an anion exchange resin neutralized with formate. To obtain formate of PAS-92 (concentration 20%)
(註 10) PAS-M-1 Methyl diallylamine polymer hydrochloride manufactured by Nittobo Co., Ltd. (concentration 60%)

      Tables 4 and 5 summarize the paint properties and coating test results.

(註 11) The stability of each paint is evaluated at 50 ° C. for 1 week.
○: No change in properties from the initial stage ×: Aggregate generation (註 12) Test material: A coating film having a wet film thickness of 250 μm is formed on a glass plate and dried under conditions of a temperature of 23 ° C. and a humidity of 50%.
Test method: Using a test roll having a weight of 15.8 kg and having a soft tire made of synthetic rubber specified in JIS-K5665, test the drying time until the paint film does not adhere to the tire by rolling on the paint film. To do. The drying time is preferably within 10 minutes.

  The water-based coating composition of the present invention is a normally-dry type, extremely quick-drying, has good coating film properties, and is mainly used for building exterior and interior applications, floor applications, iron member applications, road applications, and the like. Moreover, since it is particularly excellent in asphalt adhesion, it is particularly suitable for road use.

Claims (5)

  (1) An aqueous dispersion resin obtained by polymerizing an α, β-ethylenically unsaturated monomer containing 50% by weight or more of an acrylic acid ester or a methacrylic acid ester, having an average particle size of 50 to 200 nm and a particle size A base resin having a standard deviation of 100 nm or less, (2) an amine polymer obtained by polymerizing an allyl group-containing secondary or tertiary amine, and (3) an excess of volatility from the amino group of (2) A quick-drying aqueous coating composition containing a base as an essential component.   The quick-drying aqueous coating composition according to claim 1, wherein the acid value of the aqueous dispersion base resin (1) is 0.5 to 40 KOHmg / g.   The quick-drying aqueous coating composition according to claim 1 or 2, wherein the amine polymer (2) is obtained by polymerizing an amine containing two allyl groups.   The quick-drying aqueous coating composition according to claim 1, 2, or 3, wherein the amine polymer (2) is neutralized with an organic acid. The quick-drying aqueous coating composition according to claim 4, wherein the organic acid is formic acid or acetic acid.