JP2008231173A - Acrylic emulsion coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic emulsion coating composition which has good adhesion to various materials to be coated and exhibits excellent performance balanced with respect to various performances such as weatherability, water resistance and wet heat resistance. <P>SOLUTION: The acrylic emulsion coating composition comprises an acrylic emulsion having a pH/25°C of 5.0-7.8 which is obtained by the emulsion copolymerization of an acrylic monomer containing at least any one kind of a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth)acryloyl groups in the molecule in the presence of a cycloazoamidine compound as an emulsion polymerization initiator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an acrylic emulsion coating composition that has excellent adhesion to various objects to be coated and exhibits excellent performance that is balanced in various properties such as weather resistance, water resistance, and moist heat resistance.

  Super water-repellent film formation, water / water-repellent treatment for automobiles and building materials, water-repellent gas diffusion electrode layer in fuel cells, partial water-repellent surface on fuel cell electrode catalyst, for secondary batteries It attracts attention as a highly expected technology such as water repellency and waterproofing of hydrogen storage alloy electrodes, water repellency of electric double layer capacitors, and water repellency of solar cell panels (see Non-Patent Document 1).

  As a method for forming a water-repellent surface, a method using a material having a small surface energy (for example, a fluororesin), a method for learning from the natural world and forming a lotus leaf-like surface have been proposed. Since the former technique has a limit in water repellency, in recent years, the main research and development has been focused on the latter. That is, a method of forming a lotus leaf-like uneven surface, a method of forming a smaller unevenness in a large unevenness, a method of forming a so-called fractal surface.

  A method for producing a water-repellent surface intended to form a super water-repellent film by agglomerating silica or titania inorganic fine particles during film formation, that is, by stacking inorganic fine particles in a direction perpendicular to the surface to be water-repellent is shown. (See Patent Document 1 and Patent Document 2). The technique proposed in Patent Document 1 and Patent Document 2 is a technique that combines the formation of large irregularities with a binder and the formation of small irregularities with inorganic fine particles, or a technique that combines smaller irregularities using the small surface energy of the binder. It is guessed. Both techniques utilize the aggregation of inorganic fine particles, that is, the collapse of dispersion stabilization, and it is speculated that the binding force of the inorganic fine particles by the binder is weak, and water repellency is expressed only at the initial stage of film formation. There is concern about the durability of water repellency when placed in a harsh natural environment or under high temperature and high humidity.

  A technique for forming a water-repellent surface by forming an uneven structure on the surface of a coating film due to a difference in the curing rate of the binder during heat curing is disclosed (see Patent Document 3). The technique proposed in Patent Document 3 corresponds to a phenomenon in which so-called creaking occurs because the surface curability of the coating is too early, although it should have originally aimed to form a smooth coating film. The technique proposed in Patent Document 3 uses trialkoxysilane as the main raw material and may exhibit water repellency, but is uneasy in terms of adhesion to a substrate forming a water-repellent surface and water-repellent coating strength. Remains. Further, as in the proposals of Patent Document 1 and Patent Document 2, there remains anxiety in terms of durability of the water-repellent coating and durability of the water-repellent coating film.

  A technology for a water-repellent film that continues and maintains super water repellency even after environmental tests (water resistance, weather resistance, etc.) have been introduced (see Non-Patent Document 2). The technique introduced in Non-Patent Document 2 does not have adhesion to an object to be coated. In non-destructive environmental tests such as spraying water or irradiating light, it is effective, but in the natural environment where the treated material is exposed, dust such as dust, dust and sand particles There is also a great possibility that the treated surface will be damaged or scratches or cuts will occur. For coatings that do not adhere to the object, it is common for water to enter from the scratched surface, causing the coatings to bulge and peel off, and they will perform well in non-destructive environmental tests. However, there are still doubts about practical use.

In addition, the techniques proposed in Patent Document 1, Patent Document 2, and Patent Document 3 can form only a thin film of several microns or less, which is too thin for practical use, and there is a concern about durability. Moreover, in an actual environment, the contamination of the coating film is sufficiently considered, and there is no material to worry about the water repellency when the uneven surface is contaminated and the unevenness is absent. Furthermore, practical tests such as adhesion of the coating material forming the water repellent surface to the adherend, weather resistance, and heat and humidity resistance have not been discussed at all, and are also a concern.
JP 2003-238947 A JP 2006-232870 A JP 2000-144116 A “Hydrophilic surface to super water-repellent surface by nanostructure control”, Hosono, Shu, AIST (AIST) TODAY VOL6 No. 1, p26-27 (2006.1.1) “NTT AT Advanced Technology Product Introduction Site”, [online], NTT-AT, [Search February 5, 2007], Internet <URL: http: // www. keytech. ntt-at. co. jp / environ / prd_4001. html>

  The problem to be solved by the present invention is to provide an acrylic emulsion coating composition that has excellent adhesion to various objects to be coated, balances various performances such as weather resistance, water resistance, and moist heat resistance, and exhibits excellent performance. Is to get.

  The present invention uses a cycloazoamidine compound as an emulsion polymerization initiator, and includes at least one of a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule. Is an acrylic emulsion coating composition comprising an acrylic emulsion having an emulsion copolymerized acrylic monomer having a pH / 25 ° C. of 5.0 to 7.8.

  The acrylic emulsion coating composition of the present invention has good storage stability and can be used stably without causing precipitation or separation even during long-term storage.

  The acrylic emulsion paint composition of the present invention is a safe and secure paint composition that is environmentally friendly and health-friendly because water is the main dispersion medium or solvent.

  The acrylic emulsion paint composition of the present invention exhibits good adhesion to various coated materials such as metals such as aluminum alloys, ABS resins, polyester resins, methacrylic resins, polycarbonate resins, and is weather resistant, water resistant, moisture resistant Excellent performance is achieved by balancing various performances such as thermal properties. The acrylic emulsion coating composition of the present invention is excellent in rust prevention properties of metals such as aluminum alloys.

  The acrylic emulsion paint composition of the present invention can form a continuous water-repellent coating film having a contact angle / 23 ° C. of 85 ° or more on the surface of the article to be coated.

  The present invention uses a cycloazoamidine compound as an emulsion polymerization initiator, and includes at least one of a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule. Is an acrylic emulsion coating composition comprising an acrylic emulsion having an emulsion copolymerized acrylic monomer having a pH / 25 ° C. of 5.0 to 7.8.

  The acrylic emulsion contained in the acrylic emulsion coating composition of the present invention is an acrylic emulsion in which an acrylic polymer produced by emulsion polymerization of an acrylic monomer is stably dispersed and emulsified in water (reference: “synthetic resin emulsion”). "Hiraku Okuda, Hiroshi Inagaki, Polymer Publishing Association (1986). The acrylic emulsion used in the acrylic emulsion coating composition of the present invention is preferably produced by emulsion polymerization of an acrylic monomer using ion exchange water as a medium.

  The acrylic emulsion contained in the acrylic emulsion coating composition of the present invention uses a cycloazoamidine compound as an emulsion polymerization initiator, and the acrylic emulsion produced by emulsion copolymerization has a pH / 25 ° C. of 5.0 to 7.8. It is.

  The cycloazoamidine compound used as a polymerization initiator in the present invention preferably has a unit represented by the following structural formula in the molecule,

(However, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
Preferably, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] (“VA-061” manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis {2- [1- ( 2-hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride (“VA-060” manufactured by Wako Pure Chemical Industries, Ltd.). In the present invention, these cycloazoamidine compounds may be used alone or in a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, the cycloazoamidine compound is preferably 0.005 to 5.0 parts by weight, more preferably 0.005 parts by weight with respect to 100 parts by weight of the acrylic monomer constituting the acrylic emulsion. It is desirable to use 0.5 to 3.0 parts by weight, more preferably 0.05 to 2.0 parts by weight. In this invention, when the usage-amount of a cycloazoamidine compound is less than 0.005 weight part, the tendency for the sclerosis | hardenability of a coating to worsen is seen, and water resistance and heat-and-moisture resistance may deteriorate. When the usage-amount of a cycloazoamidine compound exceeds 5.0 weight part, the tendency for the storage stability of an acrylic emulsion to deteriorate is seen.

  In the present invention, the cycloazoamidine compound improves the storage stability of an acrylic emulsion, and in particular, when an acrylic monomer containing an oxirane group-containing acrylic monomer is emulsion copolymerized, the oxirane group is stably protected. There is a trend. Furthermore, the cycloazoamidine compound is a crosslinked coating film that improves the reaction curability of an acrylic emulsion obtained by emulsion copolymerization of an acrylic monomer containing an oxirane group-containing acrylic monomer, and is excellent in water resistance and chemical resistance. The tendency to form is seen.

  The acrylic emulsion used in the present invention has a pH / 25 ° C. of 5.0 to 7.8, preferably 5.3 to 7.5, and more preferably 5.5 to 7.2. When the pH / 25 ° C. of the acrylic emulsion used in the acrylic emulsion paint composition of the present invention is less than 5.0, repelling is likely to occur when the acrylic emulsion paint is applied to an article, resulting in a coating defect. . When pH / 25 degreeC of an acrylic emulsion exceeds 7.8, the sclerosis | hardenability of an acrylic emulsion coating composition will deteriorate, and a durable coating film will not be formed.

  In the acrylic emulsion paint composition of the present invention, an acrylic monomer containing at least one of a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule The body is emulsion copolymerized.

  In the present invention, it is recommended that the acrylic emulsion used in the present invention is an acrylic emulsion obtained by emulsion copolymerization of an acrylic monomer containing a fluoroalkyl group-containing acrylic monomer.

  In the acrylic emulsion used in the present invention, as the fluoroalkyl group-containing acrylic monomer, 2,2,2-trifluoroethyl methacrylate, tetrafluoropropyl acrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octa Examples include fluoropentyl methacrylate and heptadecafluorodecyl methacrylate. In the present invention, these fluoroalkyl group-containing acrylic monomers may be used singly or as a mixture of two or more.

  In the acrylic emulsion coating composition of the present invention, the surface energy of the coating film is reduced by the action of fluorine atoms by using an acrylic emulsion obtained by emulsion copolymerization of an acrylic monomer containing a fluoroalkyl group-containing acrylic monomer. There is an improvement in water repellency that seems to be due to the decrease.

  In the acrylic emulsion paint composition of the present invention, the fluoroalkyl group-containing acrylic monomer is preferably 0.2 to 50% by weight, more preferably 0.5 to 50% by weight, and still more preferably 3% in the acrylic emulsion. It is desirable that the emulsion copolymerization is from 0 to 30% by weight.

  In the acrylic emulsion paint composition of the present invention, when the use amount of the fluoroalkyl group-containing acrylic monomer is less than 0.2% by weight, the effect of coating film durability, water repellency, etc. is not so great There is. When the amount of the fluoroalkyl group-containing acrylic monomer exceeds 50% by weight, the emulsion copolymerization may not be carried out successfully, and it becomes necessary to increase the amount of the emulsifier in order to stabilize the emulsion. There is a tendency for the water resistance and heat-and-moisture resistance to deteriorate.

  In the present invention, the acrylic emulsion used in the present invention is an acrylic emulsion in which an acrylic monomer containing a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule is emulsion-copolymerized. It is recommended.

  In the acrylic emulsion used in the present invention, the polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule is preferably ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, Polyethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, ditetramethylene glycol diacrylate, ditetramethylene Glycol dimethacrylate, polytetramethylene glycol diacrylate, polytetramethylene glycol dimethacrylate, trimethyl Propane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, epoxy diacrylate, epoxy dimethacrylate, polyurethane diacrylate oligomer, polyester diacrylate oligomer, etc. Is exemplified. In the present invention, the polyfunctional acrylic monomer having two or more (meth) acryloyl groups in these molecules may be used singly or as a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, an acrylic monomer containing a polyfunctional acrylic monomer is emulsion-copolymerized in the acrylic emulsion to be used, thereby increasing coating film hardness and improving water repellency. May be.

  In the acrylic emulsion used in the present invention, the polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule is preferably 0.02 to 20% by weight, more preferably in the acrylic emulsion. It is desirable that the emulsion copolymerization is 0.2 to 10% by weight, more preferably 0.5 to 8% by weight. In the acrylic emulsion coating composition of the present invention, when the amount of the polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule is less than 0.02% by weight, the coating film is not crosslinked. There is a tendency that the water resistance, moist heat resistance, and weather resistance of the coating film are deteriorated due to insufficientness. Moreover, the effect | action which leveles and smoothes a coating film becomes strong, and fine unevenness | corrugation cannot be controlled well and water repellency may fall. When the amount of these polyfunctional acrylic monomers used exceeds 20% by weight, the coating film becomes brittle, and the adhesion and impact resistance of the coating film tend to deteriorate.

  In the acrylic emulsion used in the present invention, in addition to a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule, an acrylic monomer that is emulsion copolymerized The body is preferably methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, propyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, acrylic acid Stearyl, dodecyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, Molecules such as (meth) acrylic acid alkyl esters, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, 3-ethyl-3-methacryloyloxymethyloxetane, such as lauryl tacrylate, stearyl methacrylate, dodecyl methacrylate, zobornyl methacrylate An oxirane group-containing acrylic monomer having an oxirane group, oxetanyl group and (meth) acryloyl group, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate Hydroxyl group-containing acrylic monomer having a hydroxyl group and a (meth) acryloyl group in a molecule such as 2-hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate, acrylic acid, methacrylate A carboxyl group-containing acrylic monomer having a carboxyl group and a (meth) acryloyl group in a molecule such as phosphoric acid or β-carboxyethyl acrylate, and an alkoxysilyl group and a (metha) group in a molecule such as γ-methacryloyloxypropyltrimethoxysilane. ) An alkoxysilyl group-containing acrylic monomer having an acryloyl group is exemplified. In the acrylic emulsion used in the acrylic emulsion paint composition of the present invention, these acrylic monomers may be used singly or as a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, among these acrylic monomers, oxirane groups and glycanyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, 3-ethyl-3-methacryloyloxymethyloxetane, Oxirane group-containing acrylic monomer having oxetanyl group and (meth) acryloyl group, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-methacrylic acid 2- It is recommended that a hydroxyl group-containing acrylic monomer having a hydroxyl group and a (meth) acryloyl group in a molecule such as hydroxypropyl or 4-hydroxybutyl methacrylate is emulsion-copolymerized.

  In the acrylic emulsion coating composition of the present invention, when an acrylic emulsion obtained by emulsion copolymerization of an oxirane group-containing acrylic monomer and an acrylic monomer containing a hydroxyl group-containing acrylic monomer is used, an aluminum alloy, iron, copper There is a tendency to improve the adhesion to metals such as, and a tendency to improve the curability and crosslinkability of the paint. Furthermore, when an oxirane group-containing acrylic monomer and a hydroxyl group-containing acrylic monomer are used in combination, the rust prevention properties of metals such as aluminum alloy, stainless steel, and nickel tend to be greatly improved, which is desirable.

  In the acrylic emulsion used in the present invention, the oxirane group-containing acrylic monomer is preferably 3 to 30% by weight, more preferably 5 to 25% by weight, and further preferably 8 to 20% by weight in the acrylic emulsion. % Emulsion copolymerization is desirable. The hydroxyl group-containing acrylic monomer is preferably emulsion-copolymerized in the acrylic emulsion, preferably 5 to 30% by weight, more preferably 8 to 25% by weight, and still more preferably 8 to 16% by weight. When the oxirane group-containing acrylic monomer or the hydroxyl group-containing acrylic monomer is contained in the acrylic emulsion in an amount of 5 to 30% by weight, the adhesion and curability of the acrylic emulsion coating composition tend to be improved. .

  Furthermore, in the present invention, the acrylic emulsion used in the present invention comprises an acrylic monomer containing an ultraviolet absorbing group-containing acrylic monomer (hereinafter also referred to as RUVA) having an ultraviolet absorbing group and a (meth) acryloyl group in the molecule. It is recommended that the monomer is an emulsion copolymerized acrylic emulsion. In the present invention, the UV-absorbing group-containing acrylic monomer (RUVA) is preferably exemplified by 2- (2′-hydroxy-5′-methacryloxyethylphenyl) -2H-benzotriazole.

  In the present invention, commercially available compounds can be arbitrarily used as the UV-absorbing group-containing acrylic monomer (RUVA). For example, “RUVA-93” (reactive UV light from Otsuka Chemical Co., Ltd.) is preferable. An absorbent).

  When the acrylic emulsion used in the present invention is emulsion-copolymerized with a UV-absorbing group-containing acrylic monomer (RUVA), it tends to improve the weather resistance of the coating film and is recommended. At the same time, the durability of the coating film is improved, and the water repellency of the coating film tends to last for a long time.

  In the acrylic emulsion used in the present invention, the UV-absorbing group-containing acrylic monomer (RUVA) is preferably 0.2 to 35% by weight of the acrylic emulsion, more preferably 0.5 to 30% by weight, More preferably, it is desirable to carry out emulsion copolymerization of 2 to 20% by weight. When UV-absorbing group-containing acrylic monomer (RUVA) is emulsion-copolymerized in an amount of 0.2 to 35% by weight of the acrylic emulsion, the weather resistance is improved and the durability of water repellency tends to be exhibited. It is done.

  The cycloazoamidine compound contained in the acrylic emulsion paint composition of the present invention is used as an emulsion polymerization initiator, a fluoroalkyl group-containing acrylic monomer, and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule The acrylic emulsion having pH / 25 ° C. of 5.0 to 7.8 obtained by emulsion copolymerization of an acrylic monomer containing any one or more of the body preferably has an average particle size of 30 to 200 nm. The thickness is preferably 30 to 160 nm, and more preferably 30 to 150 nm.

  In the present invention, the average particle size of the acrylic emulsion was measured at 25 ° C. using a “concentrated particle size analyzer FPAR-1000” (particle size measuring device manufactured by Otsuka Electronics Co., Ltd.).

  In the acrylic emulsion paint composition of the present invention, when the average particle diameter of the acrylic emulsion used in the present invention is less than 30 nm, the unevenness of the formed coating film surface becomes too fine and sufficient water repellency is exhibited. It may not be done. When the average particle diameter of the acrylic emulsion used in the present invention exceeds 200 nm, the water resistance and heat-and-moisture resistance of the paint tend to deteriorate.

  In the present invention, more preferably, the acrylic emulsion used in the present invention is an acrylic emulsion having an average particle size of preferably 30 to 100 nm, more preferably 30 to 80 nm, and still more preferably 30 to 70 nm. It is recommended to include.

  In this invention, the average particle diameter of the acrylic emulsion preferably used by this invention is 30-100 nm, the unevenness | corrugation of a coating film does not become too fine, and water repellency is fully exhibited.

  Hereinafter, an acrylic emulsion having an average particle diameter of 30 to 100 nm preferably used in the present invention is referred to as an acrylic emulsion (SE).

  Further, in the acrylic emulsion (SE) preferably used in the present invention, the fluoroalkyl group-containing acrylic monomer is preferably 3 to 80% by weight, more preferably 5 to 80% by weight, and still more preferably 8 to 60% by weight of the emulsion copolymerization is desirable. When the copolymerization amount of the fluoroalkyl group-containing acrylic monomer of the acrylic emulsion (SE) preferably used in the present invention is 3 to 80% by weight, the surface of the coating film by copolymerization of the fluoroalkyl group-containing acrylic monomer Energy lowering effect is seen and water repellency is fully exhibited. In addition, when the amount of the fluoroalkyl group-containing acrylic monomer copolymerized in the acrylic emulsion (SE) preferably used in the present invention is 3 to 80% by weight, the acrylic emulsion (SE) preferably used in the present invention is applied. Good adhesion to the film and good paint durability.

  Furthermore, the acrylic emulsion (SE) preferably used in the present invention is preferably a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule, preferably 0.05 to 10% by weight, More preferably, it is 0.5 to 10% by weight, and further preferably 0.5 to 8% by weight. When the copolymerization amount of the polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule of the acrylic emulsion (SE) preferably used in the present invention is 0.05 to 10% by weight, Fine irregularities are formed on the film surface, and the water repellency of the coating film is sufficiently exhibited. Moreover, the polyfunctional acrylic monomer copolymerization amount which has two or more (meth) acryloyl groups in the molecule | numerator of the acrylic emulsion (SE) preferably used by this invention is 0.05 to 10 weight%. The coating film does not become rough and the coating film does not have a matte appearance, which is preferable in terms of design.

  In the acrylic emulsion paint composition of the present invention, the acrylic emulsion used in the present invention may further include an acrylic emulsion (LE) having a larger average particle size than the acrylic emulsion (SE) preferably used in the present invention. Recommended.

  In the acrylic emulsion paint composition of the present invention, the acrylic emulsion to be used includes an acrylic emulsion (SE) having a smaller average particle size and an acrylic emulsion (LE) having a larger average particle size. There is a tendency that fine irregularities are controlled and the water repellency of the coating film tends to be high.

  In the acrylic emulsion paint composition of the present invention, preferably, a coating film structure is formed in which a gap between acrylic emulsions (LE) having a larger average particle size is filled with acrylic emulsions (SE) having a smaller average particle size. It is inferred that the water resistance, moist heat resistance and weather resistance of the coating tend to be improved as compared with the case where each of the acrylic emulsion (SE) and the acrylic emulsion (LE) is used alone.

  The acrylic emulsion (LE) preferably used in the present invention has an average particle size of preferably 50 to 160 nm, more preferably 50 to 150 nm, and still more preferably 60 to 120 nm. When the average particle diameter of the acrylic emulsion (LE) preferably used in the present invention is 50 to 160 nm, the coating film is not too smooth and water repellency is sufficiently exhibited. When the average particle diameter of the acrylic emulsion (LE) preferably used in the present invention exceeds 160 nm, the coating film has good water resistance and wet heat resistance.

  Furthermore, in the acrylic emulsion (LE) preferably used in the present invention, the fluoroalkyl group-containing acrylic monomer is preferably 0 to 30% by weight, more preferably 0 to 25% by weight, and still more preferably 0 to 0%. It is desirable to copolymerize 20% by weight. When the copolymerization amount of the fluoroalkyl group-containing acrylic monomer is 30% by weight or less, the paint does not repel and coating film defects such as craters do not occur.

  Furthermore, the acrylic emulsion (LE) preferably used in the present invention is preferably a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule, preferably 0.0 to 3% by weight. The copolymerization is preferably 0.02 to 2% by weight, more preferably 0.05 to 5% by weight. When an acrylic emulsion (LE) preferably used in the present invention is copolymerized with a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule, fine irregularities are formed on the coating film. It is easy, water repellency is exhibited, the coating film is not roughened, the coating film does not have a matte appearance, and is preferable in terms of design.

  In the acrylic emulsion paint composition of the present invention, the total content of acrylic emulsion (SE) and acrylic emulsion (LE) is 100 parts by weight, and the solid content of acrylic emulsion (SE) is preferably 2 to 98% by weight, more preferably 5 to 80% by weight, and still more preferably 15 to 60% by weight. In the acrylic emulsion paint composition of the present invention, if the amount of the solid content of the acrylic emulsion (SE) is 2 to 98% by weight, fine irregularities of the coating film are well formed and water repellency is good.

  In the present invention, the solid content of the acrylic emulsion was determined by measuring the heating residue according to JIS K5400 (1997), and setting it as the solid content.

  The acrylic emulsion used in the present invention, for example, preferably uses ion-exchanged water as a medium and preferably has a polymerization temperature of 30 to 100 ° C., and the produced acrylic polymer is stably dispersed and emulsified in water. In the acrylic emulsion paint composition of the present invention, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether is preferably used as an emulsifier to form a polymerization field for emulsion polymerization. , Nonionic surfactants such as polyoxyethylene alkyl phenyl ether, sodium lauryl sulfate, higher alcohol sodium sulfate, ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, sodium dodecylbenzenesulfonate, Anionic surfactants such as sodium alkylnaphthalene sulfonate and sodium dialkyl succinate are used. In the present invention, more preferably, “Latemul S-180”, “Latemul S-180A”, “Latemul PD-104” (reactive emulsifier of Kao Corporation), “Antox-MS-60”, “Antox- "MS-2N", "RA-100" (reactive emulsifier of Nippon Emulsifier Co., Ltd.), "Adekariasorb NE-10", "Adekariasorb NE-20", "Adekariasorb SE-10N", "Adekariasorb SE-1025N" ( As described above, a reactive emulsifier such as Asahi Denka Kogyo Co., Ltd.) is used, a cycloazoamidine compound is used as a polymerization initiator, and an acrylic monomer is emulsion-copolymerized in water.

  As an emulsion polymerization method, a pre-emulsion method in which an acrylic monomer is emulsified and dispersed in water in advance, a monomer feed method in which an acrylic monomer is sequentially fed into water, and a part of the acrylic monomer. The seed emulsion polymerization method is known in which the emulsion is preliminarily charged into the polymerization system (previously charged water), emulsified, and preliminarily polymerized as necessary. The acrylic emulsion used in the present invention is any method. May be manufactured.

  It is recommended that the acrylic emulsion paint composition of the present invention contains an oxetane compound.

  In the acrylic emulsion paint composition of the present invention, the oxetane compound is preferably 3-ethyl-3-methacryloyloxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxy). Methyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 1,4-bis [[(3-ethyl-3-oxetanyl) methoxy] methyl] oxetane, 3-ethyl-3- (phenoxymethyl) Examples include oxetane, oxetanylsilsesquioxane, phenol novolac oxetane and the like. These oxetane compounds may be used alone or as a mixture of two or more.

  Examples of these oxetane compounds that are marketed include, for example, “Aron Oxetane OXT-101”, “Aron Oxetane OXT-121” (Oxetane Compound of Toagosei Co., Ltd.), “ETERRNACOLL OXBP” (Ube Industries, Ltd.) Oxetane compounds) and the like. These oxetane compounds may be used alone or as a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, the oxetane compound forms a continuous coating film with good adhesion on the surface of the object to be coated, and strongly binds the acrylic emulsion particles, resulting in water resistance, moist heat resistance, and weather resistance. There is a tendency to form excellent water-repellent coatings.

  In the acrylic emulsion paint composition of the present invention, it is recommended to use 3-ethyl-3-hydroxymethyloxetane as the oxetane compound. By using 3-ethyl-3-hydroxymethyloxetane, the storage stability, film formability, and adhesion of the acrylic emulsion coating composition of the present invention are improved, and the water resistance, moist heat resistance, and chemical resistance of the coating film are improved. , Weather resistance is improved.

  In the acrylic emulsion coating composition of the present invention, the oxetane compound is preferably 1 to 80% by weight, more preferably 3 to 100 parts by weight of the total amount of the solid content of the acrylic emulsion used and the oxetane compound. It is desirable to use 80% by weight, more preferably 5 to 80% by weight. In the present invention, when the amount of the oxetane compound used is less than 1% by weight, the tendency of the acrylic emulsion coating composition to decrease the wettability of the coating composition is observed, and the adhesion and uniformity of the coating film deteriorate. The case is seen. When the amount of the oxetane compound used exceeds 80% by weight, the storage stability of the acrylic emulsion coating composition may be deteriorated, and a viscosity increase or gelation may be observed with storage.

  Furthermore, in the present invention, it is desirable that the acrylic emulsion paint composition contains a photostable compound (hereinafter also referred to as HALS) having a base constant (pKb) of 8 or more. In the present invention, the photostable compound (HALS) having a pKb of 8 or more is preferably 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl]- 4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine) and the like are exemplified.

  In the acrylic emulsion paint composition of the present invention, when a photostable compound (HALS) having a pKb of 8 or more is contained, the weather resistance of the coating tends to be improved without impairing the storage stability and curability of the paint. Is seen and recommended. Examples of the photostable compound marketed as a photostable compound (HALS) having a pKb of 8 or more preferably used in the present invention include “Sanol LS-2626” (product of Sankyo Lifetech Co., Ltd.).

  In the acrylic emulsion coating composition of the present invention, the method of adding the light-stable compound (HALS) having a pKb of 8 or more is the same as that of the acrylic emulsion using HALS when the acrylic emulsion used in the present invention is produced by emulsion copolymerization. It is recommended to carry out emulsion copolymerization of an acrylic monomer in a state of being dissolved in a monomer, and to incorporate HALS into the acrylic copolymer simultaneously with the formation of the acrylic copolymer.

  By this production method and the HALS addition method, the storage stability of the acrylic emulsion coating composition is improved, and at the same time, the HALS effect tends to be more easily exhibited.

  In the present invention, the light-stable compound (HALS) having a pKb of 8 or more is preferably 0.2 to 10 parts by weight, more preferably 0 to 100 parts by weight of the acrylic emulsion solid content used in the present invention. 5 to 8 parts by weight, more preferably 2.0 to 6 parts by weight is desirable. When 0.2 to 10 parts by weight of a light-stable compound (HALS) having a pKb of 8 or more is used with respect to 100 parts by weight of the acrylic emulsion solid content, the weather resistance, the storage stability of the paint, and the curability are the most It is well-balanced and the water repellency of the coating is maintained for a long time.

  Furthermore, the acrylic emulsion coating composition of the present invention preferably contains a silane compound having an oxirane group and an alkoxysilane group in the molecule. When a silane compound having an oxirane group and an alkoxysilane group is contained in the molecule, adhesion and rust prevention are improved when the acrylic emulsion coating composition of the present invention is applied to a metal such as an aluminum alloy, iron or stainless steel. .

  As the silane compound having an oxirane group and an alkoxysilane group in the molecule preferably used in the present invention, preferably γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Examples include propylmethyldimethoxysilane, γ-glycidoxypropylethyldimethoxysilane, 3,4-epoxycyclohexylmethyltrimethoxysilane, 3,4-epoxycyclohexylmethyltriethoxysilane, and the like. In the present invention, the silane compounds having an oxirane group and an alkoxysilane group in these molecules may be used singly or as a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, the silane compound having an oxirane group and an alkoxysilane group in these molecules is dissolved in the acrylic monomer at the time of production of the acrylic emulsion and is simultaneously with the emulsion copolymerization of the acrylic monomer. It is desirable to incorporate it into polymer particles, and the production method further improves the storage stability, adhesion, rust prevention, and weather resistance of the acrylic emulsion coating composition of the present invention.

In the acrylic emulsion coating composition of the present invention, the silane compound having an oxirane group and an alkoxysilane group in the molecule is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the acrylic emulsion solid content used in the present invention. More preferably, it is desirable to use 2.0 to 16 parts by weight, still more preferably 3.0 to 15 parts by weight. When the silane compound having an oxirane group and an alkoxysilane group in the molecule is used in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the acrylic emulsion solid content used in the present invention, the acrylic emulsion paint composition of the present invention The adhesion of various objects to various objects to be coated is improved, and the water resistance, moist heat resistance and weather resistance are improved.
In the present invention, it is recommended to use a cationic polymerization initiator in order to crosslink the acrylic emulsion coating composition and form a tough and durable coating film.

Preferred examples of the cationic polymerization initiator used in the present invention include diazonium salts, iodonium salts, sulfonium salts and the like. The products on the market are “AMERICURE (BF ₄ )” (above, ACC diazonium salt), “ULTRASET (BF ₄ , PF ₆ )” (above, Asahi Denka Kogyo diazonium salt), “UVE series” (Above GE iodonium salt), "Photoinitiator 2074 ((C ₆ F ₆ ) ₄ B)" (above, Rhone Pulan iodonium salt), "CYRACURE UVI-6974", "CYRACURE UVI-6990" ( As described above, sulfonium salt of UCC), “UVI-508”, “UVI-509” (above, sulfonium salt of GE), “OPTOMER SP-150”, “OPTOMER SP-170” (sulfonium of Asahi Denka Kogyo Co., Ltd.) Salt), "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L" (Sanshin Chemical Industries sulfonium salt), "IRUGACURE 261" (Ciba Geigy's metallocene compound) Is done. These cationic polymerization initiators may be used alone or as a mixture of two or more.

  In the acrylic emulsion paint composition of the present invention, among these cationic polymerization initiators, a sulfonium salt is preferably recommended from the viewpoint of storage stability and curability of the acrylic emulsion paint composition. The sulfonium salt used in the adhesive composition of the present invention is preferably a sulfonium salt represented by the following structural formula.

(However, R1, R2, and R3 represent an alkyl group having 1 to 12 carbon atoms.)

(However, R1, R2, and R3 represent an alkyl group having 1 to 12 carbon atoms.)

  In the acrylic emulsion paint composition of the present invention, these sulfonium salts are preferably methylphenyldimethylsulfonium hexafluoroantimony salt, ethylphenyldimethylsulfonium hexafluoroantimony salt, methylphenyldimethylsulfonium hexafluorophosphate salt, and the like. Illustrated. These sulfonium salts may be used alone or as a mixture of two or more.

  The sulfonium salt marketed as the sulfonium salt used in the acrylic emulsion paint composition of the present invention is preferably “Sun-Aid SI-60L”, “Sun-Aid SI-80L”, “Sun-Aid SI-100L” (above, Sanshin Chemical Co., Ltd.), "UVI-6990", "UVI-6922", "UVI-6974" (product of Union Carbide), "Adekaoptomer SP-150", "Adekaoptomer SP" -170 "," Adeka Opton CP-66 "," Adeka Opton CP-77 "(product of Asahi Denka Kogyo Co., Ltd.)," IRGACURE 261 "(product of Ciba Geigy Co., Ltd.) and the like.

  In the acrylic emulsion paint composition of the present invention, preferably “Sun-Aid SI-15”, “Sun-Aid SI-30”, “Sun-Aid SI-45”, “Sun-Aid SI-60L”, “Sun-Aid SI-80L”, “Sun-Aid SI” A cationic polymerization initiator designed with particular emphasis on thermosetting is recommended, such as “-100 L” (product of Sanshin Chemical Co., Ltd.).

  In the acrylic emulsion paint composition of the present invention, these cationic polymerization initiators are preferably 0.02 to 10 parts by weight, more preferably 0.8 parts per 100 parts by weight of the oxetane compound used in the present invention. It is desirable to use 2 to 8 parts by weight, more preferably 0.5 to 5 parts by weight. In this invention, when the usage-amount of a cationic polymerization initiator is 0.02-10 weight part, the tendency for the storage stability and sclerosis | hardenability of an acrylic emulsion coating composition to improve is seen, and desirable.

  As for the coated article in which the coating film was formed with the acrylic emulsion coating composition of this invention, it is desirable that the contact angle of water with respect to the coating film measured at 23 degreeC is 85 degrees or more.

In the present invention, “FACE CONACT-ANGLE METER” manufactured by Kyowa Interface Chemical Co., Ltd. was used as the contact angle.
The contact angle of the coating film formed from the acrylic emulsion paint composition of the present invention is desirably 85 ° or more, preferably 90 ° or more, and more preferably 100 ° or more. In the present invention, when the contact angle of the coating film is less than 85 °, there is a tendency that the water repellency and water repellency of the coating film tend to deteriorate, and the phenomenon that the coating film surface gets wet with water tends to occur. . As a result, the coating film tends to contain water, and the coating film that has absorbed water no longer exhibits water repellency. Furthermore, this suggests that when the contact angle of the coating film is less than 85 °, the coating film exposed to rainfall for a long time or the coating film covered with snowfall or snowfall does not exhibit water repellency. . Also, when coated on metal, if the coating contact angle is less than 85 °, the surface of the coating tends to get wet with water, so the metal tends to corrode. In addition, the electrical insulation properties of the coating film may be lowered, and the insulation effect by the coating film and prevention of electrical leakage may not be expected.

  In the acrylic emulsion paint composition of the present invention, additives, pigments and the like commonly used in acrylic emulsion paints, that is, surfactants, antifoaming agents, slipping agents, thickeners, antiseptics, algaeproofing agents, A mold agent, titanium dioxide, silica fine particles, talc and the like may be used.

  The acrylic emulsion coating composition of the present invention can be applied by various coating methods such as spray coating, dip coating, curtain flow coating, and roll coating. In any of the coating methods, the coating thickness can be adjusted from a thin film of about 1 μm to a thick film of about 2,30 μm. As an object to which the acrylic emulsion paint composition of the present invention can be applied, plastics such as ABS resin, polyester resin, polycarbonate resin, methacrylic resin, metals such as aluminum alloy, iron, copper, stainless steel, nickel, glass, mortar, An inorganic substance such as a gypsum board is exemplified.

    The coated article in which the water-repellent coating film having a contact angle of 85 ° or more is formed by the acrylic emulsion paint composition of the present invention is, for example, a building material such as a van truck loading platform or a roof material with improved snow removal performance as a color aluminum, solar It can be used for water-repellent treatment of battery panels, condensation of automobile evaporators, commercial and household air conditioners.

  Hereinafter, the present invention will be described in detail with examples.

  In the following examples, various tests were performed as follows. The coating film performance was evaluated by using a test piece that was baked and dried at 160 ° C. for 30 minutes after the coating was applied to a JIS A-6063 aluminum plate so that the coating thickness was 10 μm.

In the examples, the composition ratio is the weight composition unless otherwise specified. The composition ratio of the acrylic emulsion is a weight composition converted to solid content.
(1) Average particle diameter The average particle diameter was measured at 25 ° C. using a “concentrated particle size analyzer FPAR-1000” (Otsuka Electronics Co., Ltd. particle size measuring device).
(2) Solid content (= heating residue)
As for the solid content, the heating residue was measured in accordance with JIS K5400 (1997), and this was used as the solid content.
(3) Adhesion A cross-cut test was performed according to JIS K5400 (1997).
(4) Measurement of contact angle It measured at 23 degreeC using "FACE CONTACT-ANGLE METER" by Kyowa Interface Chemical Co., Ltd.
(5) Weather resistance test Using a “metal weather accelerated weather resistance tester” (manufactured by Daipla Wintes), light irradiation (wavelength 295 to 780 nm, light intensity 78 mW / cm ² , BPT 63 ° C.) 4 hours to condensation ( (Temperature 30 ° C., humidity 95% or more) 4 cycles were performed for 30 cycles. The contact angle of the coating film was compared before and after the test.
(6) Humidity and heat resistance test The coated plate was allowed to stand for 250 hours in an environment of a temperature of 60 ° C and a humidity of 90%. The contact angle of the coating film was compared before and after the test.
(7) Rust prevention The salt spray test was done according to JIS K5400 (1997).

1. Example 1 Production of Acrylic Emulsion Coating Composition
[Production Example of Acrylic Emulsion (SE-1)]
In a 1 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen gas inlet tube, and an acrylic monomer supply unit, 359.4 g of ion-exchanged water, “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) 120 g, “ VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) 0.6 g was charged and heated to 60 ° C until" VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) was completely dissolved. Stirring was performed for about 30 minutes.

  Methyl methacrylate / trimethylolpropane triacrylate / “RUVA-93” (Otsuka Chemical's UV-absorbing acrylic monomer) (= 93/2/5) 270 g of acrylic monomer mixed solution was charged into a flask. The polymerization temperature was raised to 72 ° C.

  The remaining amount (190 g) of the acrylic monomer mixed solution was dropped into the flask in 2 hours, and emulsion polymerization was further performed at 72 ° C. for 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.5 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (SE-1) had an average particle size of 58 nm, a pH of 6.5, and a solid content of 39.8%.

[Production Example of Acrylic Emulsion (LE-1)]
A 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit was charged with 210.0 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka's reactive emulsifier). The temperature was raised to 65 ° C.

  30 g of acrylic monomer mixture of n-butyl acrylate / glycidyl methacrylate / trimethylolpropane triacrylate (= 93.5 / 5.0 / 0.5) was charged, and after 1 minute, it was dissolved beforehand. A polymerization initiator aqueous solution of 15 g of ion-exchanged water and 0.075 g of “VA-061” (cycloazoamidine compound of Wako Pure Chemical Industries, Ltd.) was added. Polymerization started and the temperature of the polymerization system increased. When the polymerization temperature began to decrease while cooling, the polymerization temperature was controlled at 72 ° C., and the polymerization was continued at 72 ° C. for an additional hour.

  Methyl methacrylate / n-butyl methacrylate / n-butyl acrylate / glycidyl methacrylate / 2-hydroxyethyl methacrylate / “Blenmer PDT-650” (Nippon Yushi Co., Ltd. polytetramethylene glycol dimethacrylate) (= 40/15 / 17/15/10/3) 255 g, γ-glycidoxypropyltrimethoxysilane 30 g, “Sanol LS-2626” (Photo-stable compound of Sankyo Lifetech) 6 g mixed solution containing acrylic monomer, A pre-emulsion was prepared by applying a mixed solution of 209.4 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) to an emulsifier. The prepared pre-emulsion was dropped into the flask in 3 hours. At the same time, 60 g of ion-exchanged water and 0.3 g of “VA-061” (a cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in advance were added dropwise to the flask in 3 hours. After completion of the dropwise addition, emulsion polymerization was continued at 72 ° C. for another 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.8 g of “Adecanate B-1016” (Adeca Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (LE-1) had an average particle size of 98 nm, a pH of 6.6, and a solid content of 39.6%.

[Production example of acrylic emulsion paint (1)]
While stirring a mixture of 20 g of acrylic emulsion (LE-1) / acrylic emulsion (SE-1) (= 70/30), 2 g of γ-butyrolactone was added and further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added and stirred for another 30 minutes to produce an acrylic emulsion paint (1).

Example 2
[Production example of acrylic emulsion paint (2)]
While stirring a mixture of 20 g of acrylic emulsion (LE-1) / acrylic emulsion (SE-1) (= 70/30), 2 g of “Aron Oxetane OXT-101” (Oxetane compound of Toagosei Co., Ltd.), “Sun Aid SI-80L “(0.03 g of a cationic polymerization initiator from Sanshin Chemical Industry Co., Ltd.) was added, and the mixture was further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added, and stirring was further performed for 30 minutes to produce an acrylic emulsion paint (2).

Example 3
[Production example of acrylic emulsion (SE-2)]
In a 1 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen gas inlet tube, and an acrylic monomer supply unit, 359.4 g of ion-exchanged water, “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) 120 g, “ VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) 0.6 g was charged and heated to 60 ° C until" VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) was completely dissolved. Stirring was performed for about 30 minutes.

  Methyl methacrylate / heptadecafluorodecyl methacrylate / trimethylolpropane triacrylate / “RUVA-93” (UV absorbing acrylic monomer from Otsuka Chemical) (= 83/10/2/5) 270 g acrylic monomer 80 g of the mixed solution was charged into the flask, and the polymerization temperature was raised to 72 ° C.

  The remaining amount (190 g) of the acrylic monomer mixed solution was dropped into the flask in 2 hours, and emulsion polymerization was further performed at 72 ° C. for 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.5 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (SE-2) had an average particle size of 60 nm, a pH of 6.5, and a solid content of 40.0%.

[Production Example of Acrylic Emulsion (LE-2)]
A 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit was charged with 210.0 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka's reactive emulsifier). The temperature was raised to 65 ° C.

  30 g of acrylic monomer mixture of n-butyl acrylate / glycidyl methacrylate / trimethylolpropane triacrylate (= 93.5 / 5.0 / 0.5) was charged, and after 1 minute, it was dissolved beforehand. A polymerization initiator aqueous solution of 15 g of ion-exchanged water and 0.075 g of “VA-061” (cycloazoamidine compound of Wako Pure Chemical Industries, Ltd.) was added. Polymerization started and the temperature of the polymerization system increased. When the polymerization temperature began to decrease while cooling, the polymerization temperature was controlled at 72 ° C., and the polymerization was continued at 72 ° C. for an additional hour.

  Methyl methacrylate / n-butyl methacrylate / n-butyl acrylate / glycidyl methacrylate / 2-hydroxyethyl methacrylate / heptadecafluorodecyl methacrylate / trimethylolpropane triacrylate (= 32.8 / 15/17/15 / 10/10 / 0.2) 255 g, γ-glycidoxypropyltrimethoxysilane 30 g, “Sanol LS-2626” (Sankyo Lifetech Co., Ltd. light-stable compound) 6 g mixed solution containing acrylic monomer, ion A mixture of 209.4 g of exchange water and 30 g of “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) was put into an emulsifier to prepare a pre-emulsion. The prepared pre-emulsion was dropped into the flask in 3 hours. At the same time, 60 g of ion-exchanged water and 0.3 g of “VA-061” (a cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in advance were added dropwise to the flask in 3 hours. After completion of the dropwise addition, emulsion polymerization was continued at 72 ° C. for another 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.8 g of “Adecanate B-1016” (Adeca Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (LE-2) had an average particle size of 96 nm, a pH of 6.6, and a solid content of 39.8%.

[Production example of acrylic emulsion paint (3)]
While stirring a mixture of 20 g of acrylic emulsion (LE-2) / acrylic emulsion (SE-2) (= 70/30), 2 g of “Aron Oxetane OXT-101” (Oxetane compound of Toagosei Co., Ltd.), “Sun Aid SI-80L “(0.03 g of a cationic polymerization initiator from Sanshin Chemical Industry Co., Ltd.) was added, and the mixture was further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added and stirred for another 30 minutes to produce an acrylic emulsion paint (3).

Example 4
[Production example of acrylic emulsion (SE-3)]
269.7 g of ion-exchanged water and 240 g of “Aqualon KH-1025” (Reactive emulsifier of Daiichi Kogyo Seiyaku) in a 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit , "VA-061" (cycloazoamidine compound of Wako Pure Chemical Industries, Ltd.) 0.3g was charged and heated to 60 ° C, and "VA-061" (cycloazoamidine compound of Wako Pure Chemical Industries, Ltd.) was completely dissolved. Stirring was continued for about 30 minutes.

  Methyl methacrylate / heptadecafluorodecyl methacrylate / trimethylolpropane triacrylate / “RUVA-93” (UV absorbing acrylic monomer from Otsuka Chemical) (= 80/15/2/3) 270 g acrylic monomer 80 g of the mixed solution was charged into the flask, and the polymerization temperature was raised to 72 ° C.

  The remaining amount (160 g) of the acrylic monomer mixed solution was dropped into the flask in 2 hours, and emulsion polymerization was further performed at 72 ° C. for 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.5 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (SE-3) had an average particle size of 52 nm, a pH of 6.6, and a solid content of 39.8%.

[Production example of acrylic emulsion paint (4)]
While stirring a mixture of 20 g of acrylic emulsion (LE-2) / acrylic emulsion (SE-3) (= 70/30), 2 g of “Aron Oxetane OXT-101” (Oxetane compound of Toagosei Co., Ltd.), “Sun Aid SI-80L “(0.03 g of a cationic polymerization initiator from Sanshin Chemical Industry Co., Ltd.) was added, and the mixture was further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added, and stirring was further performed for 30 minutes to produce an acrylic emulsion paint (4).

Example 5
[Production example of acrylic emulsion paint (5)]
While stirring a mixture of 20 g of acrylic emulsion (LE-2) / acrylic emulsion (SE-3) (= 70/30), “Aron oxetane OXT-101” (Oxetane compound of Toagosei Co., Ltd.) / “Aron oxetane OXT-121” “(Oxetane compound of Toagosei Co., Ltd.) (= 80/20) 2 g,“ Sun Aid SI-80L ”(Sanshin Chemical Industry Cationic Polymerization Initiator) 0.04 g of mixed solution was added and further stirred for 30 minutes. It was. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added, and stirring was further performed for 30 minutes to produce an acrylic emulsion paint (4).

Comparative Example 1
[Production Example of Acrylic Emulsion (SE-4)]
35 L of ion-exchanged water, 120 g of “Adeka Resorb SR-1025” (Adeka's reactive emulsifier), 1 g of a 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit, 0.6 g of ammonium sulfate was charged and the temperature was raised to 70 ° C.

  Methyl methacrylate / trimethylolpropane triacrylate / "RUVA-93" (Otsuka Chemical's UV-absorbing acrylic monomer) (= 93/2/5) A mixture of 270 g of acrylic monomer mixed solution was charged into a flask. The polymerization temperature was raised to 72 ° C.

  The remaining amount (190 g) of the acrylic monomer mixed solution was dropped into the flask in 2 hours, and emulsion polymerization was further performed at 72 ° C. for 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.5 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (SE-1) had an average particle size of 82 nm, a pH of 2.4, and a solid content of 40.1%.

[Production Example of Acrylic Emulsion (LE-3)]
A 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit was charged with 210.0 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka's reactive emulsifier). The temperature was raised to 65 ° C.

  30 g of acrylic monomer mixture of n-butyl acrylate / glycidyl methacrylate / trimethylolpropane triacrylate (= 93.5 / 5.0 / 0.5) was charged, and after 1 minute, it was dissolved beforehand. A polymerization initiator aqueous solution of 15 g of ion exchange water and 0.075 g of ammonium persulfate was added. Polymerization started and the temperature of the polymerization system increased. When the polymerization temperature began to decrease while cooling, the polymerization temperature was controlled at 72 ° C., and the polymerization was continued at 72 ° C. for an additional hour.

  Methyl methacrylate / n-butyl methacrylate / n-butyl acrylate / glycidyl methacrylate / 2-hydroxyethyl methacrylate / “Blenmer PDT-650” (Nippon Yushi Co., Ltd. polytetramethylene glycol dimethacrylate) (= 40/15 / 17/15/10/3) 255 g, γ-glycidoxypropyltrimethoxysilane 30 g, “Sanol LS-2626” (Photo-stable compound of Sankyo Lifetech) 6 g mixed solution containing acrylic monomer, A pre-emulsion was prepared by applying a mixed solution of 209.4 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) to an emulsifier. The prepared pre-emulsion was dropped into the flask in 3 hours. At the same time, 60 g of ion-exchanged water and 0.3 g of ammonium persulfate, which had been previously dissolved, were dropped into the flask in 3 hours. After completion of the dropwise addition, emulsion polymerization was continued at 72 ° C. for another 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.8 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (LE-3) had an average particle size of 128 nm, a pH of 2.5, and a solid content of 39.6%.

[Production example of acrylic emulsion paint (6)]
While stirring a mixture of 20 g of acrylic emulsion (LE-3) / acrylic emulsion (SE-4) (= 70/30), 2 g of γ-butyrolactone was added and further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added and further stirred for 30 minutes to produce an acrylic emulsion paint (6).

Comparative Example 2
[Production example of acrylic emulsion (SE-5)]
In a 1 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen gas inlet tube, and an acrylic monomer supply unit, 359.4 g of ion-exchanged water, “Adeka Resorb SR-1025” (Adeka Reactive Emulsifier) 120 g, “ VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) 0.6 g was charged and heated to 60 ° C until" VA-061 "(cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) was completely dissolved. Stirring was performed. (About 30 minutes)
80 g of 270 g of acrylic monomer mixed solution of methyl methacrylate / “RUVA-93” (UV absorbing acrylic monomer of Otsuka Chemical Co., Ltd.) (= 95/5) was charged into the flask, and the polymerization temperature was raised to 72 ° C. Warm up.

  The remaining amount (190 g) of the acrylic monomer mixed solution was dropped into the flask in 2 hours, and emulsion polymerization was further performed at 72 ° C. for 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.5 g of “Adecanate B-1016” (Adeka Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (SE-5) had an average particle size of 54 nm, a pH of 6.5, and a solid content of 39.6%.

[Production Example of Acrylic Emulsion (LE-4)]
A 1 L four-necked flask equipped with a thermometer, stirrer, nitrogen gas inlet tube, and acrylic monomer supply unit was charged with 210.0 g of ion-exchanged water and 30 g of “Adeka Resorb SR-1025” (Adeka's reactive emulsifier). The temperature was raised to 65 ° C.

  30 g of acrylic monomer mixture of n-butyl acrylate / glycidyl methacrylate (= 95/5) was charged, and after 1 minute, 15 g of ion-exchanged water previously dissolved, “VA-061” (Wako Pure Chemical Industries, Ltd.) 0.075 g of a polymerization initiator aqueous solution was added. Polymerization started and the temperature of the polymerization system increased. When the polymerization temperature began to decrease while cooling, the polymerization temperature was controlled at 72 ° C., and the polymerization was continued at 72 ° C. for an additional hour.

  255 g of methyl methacrylate / n-butyl methacrylate / n-butyl acrylate / glycidyl methacrylate / 2-hydroxyethyl methacrylate (= 43/15/17/15/10), 30 g of γ-glycidoxypropyltrimethoxysilane "Sanol LS-2626" (Photo-stable compound of Sankyo Lifetech) 6 g of mixed solution containing acrylic monomer, 209.4 g of ion-exchanged water, "Adeka Resorb SR-1025" (Adeka Reactive Emulsifier) 30 g of the mixed solution was put into an emulsifier to prepare a pre-emulsion. The prepared pre-emulsion was dropped into the flask in 3 hours. At the same time, 60 g of ion-exchanged water and 0.3 g of “VA-061” (a cycloazoamidine compound manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in advance were added dropwise to the flask in 3 hours. After completion of the dropwise addition, emulsion polymerization was continued at 72 ° C. for another 2 hours.

  Then, it cooled until it became 30 degrees C or less. Next, 1.8 g of “Adecanate B-1016” (Adeca Antifoam) was added, and the mixture was further stirred at 30 ° C. or lower for 30 minutes.

  The produced acrylic emulsion (LE-4) had an average particle size of 98 nm, a pH of 6.6, and a solid content of 39.6%.

[Production example of acrylic emulsion paint (7)]
While stirring a mixture of 20 g of acrylic emulsion (LE-4) / acrylic emulsion (SE-5) (= 70/30), 2 g of γ-butyrolactone was added and further stirred for 30 minutes. Next, while stirring, 0.6 g of “Surfinol 420” (Nure agent, product of Air Products) was added and stirred for another 30 minutes to produce an acrylic emulsion paint (7).

2. Performance Test of Acrylic Emulsion Paint Composition Various tests were conducted using the acrylic emulsion paint compositions of Examples 1 to 5 and Comparative Examples 1 and 2. The characteristics of the acrylic emulsion and acrylic emulsion paint composition used in the test are shown in Tables 1 and 2, respectively. The test results are shown in Table 3.

  The coating materials 1-5 showed the favorable coating-film performance in general. In particular, paints 3, 4, and 5 in which a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer are used in combination with a fine particle acrylic emulsion (SE) have a high contact angle, a weather resistance test, a moist heat resistance test However, the performance did not decrease. Moreover, since the coating materials 1-5 made the cycloazoamidine compound the initiator of emulsion copolymerization, and the silane compound which has an oxirane group and an alkoxysilane group was mix | blended in the molecule | numerator, it was excellent also in rust prevention property.

  On the other hand, since the coating 6 did not use a cycloazoamidine compound as an emulsion copolymerization initiator, the coating had poor crosslinkability, and the adhesion, weather resistance, wet heat resistance and other performances were greatly inferior. The paint 7 does not use a polyfunctional acrylic monomer, but since the cycloazoamidine compound is used as an emulsion copolymerization initiator, the coating film is cross-linked, and the acrylic emulsion is also contributed by other parts of the present invention. As a paint, it demonstrated a high level of performance.

Claims (3)

  An acrylic monomer containing a cycloazoamidine compound as an emulsion polymerization initiator and containing at least one of a fluoroalkyl group-containing acrylic monomer and a polyfunctional acrylic monomer having two or more (meth) acryloyl groups in the molecule. An acrylic emulsion coating composition comprising an acrylic emulsion having a pH / 25 ° C. of 5.0 to 7.8, wherein the polymer is emulsion-copolymerized.   The acrylic emulsion paint composition according to claim 1, wherein the acrylic emulsion paint composition further contains an oxetane compound.   A coated article in which a water-repellent coating film having a contact angle / 23 ° C. of 85 ° or more is formed by the acrylic emulsion paint composition according to claim 1.