Flame-retardant water-based paint composition

Abstract

The present invention provides a flame-retardant water-based paint composition that can form a coating with good flame retardancy on buildings and building materials. [Solution] The flame-retardant water-based paint composition contains (A) a water-based binder resin and (B) a non-halogen-based water-soluble synthetic polymer flame retardant. As (B) the non-halogen-based water-soluble synthetic polymer flame retardant, a thermally depolymerizable polymer having a structure to which a water-soluble functional group having a specific structure is attached, its alkali metal salt, or its alkaline earth metal salt can be suitably used. In particular, poly(methacrylic acid), its alkali metal salt, or its alkaline earth metal salt can be suitably used.

Description

Technical Field

[0001] The present invention relates to a flame-retardant aqueous paint composition.

Background Art

[0002] For ensuring safety in disaster prevention, strict fire protection standards are provided for ceramic building materials boards and the like used in detached houses and the like, and flame retardancy or non-combustibility is required. As one method of imparting flame retardancy to a building material board, there is a method of coating the building material board with a flame-retardant paint. In particular, from the viewpoints of work hygiene, safety, and environmental load, aqueous flame-retardant paints are widely used. For example, Patent Document 1 discloses an aqueous flame-retardant paint containing a flame retardant and an acrylic resin emulsion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the coating film obtained from a conventional flame-retardant paint, although sufficient flame retardancy can be obtained, the water vapor permeability is high. Therefore, water vapor easily enters and exits the building materials and the like, and there is a high possibility that problems such as the building material board being easily warped occur. Also, from the viewpoint of workability, the freeze-thaw stability of the coating film may be required.

[0005] An object of the present invention is to provide a flame-retardant aqueous paint composition capable of forming a coating film having good flame retardancy on buildings, building materials, and the like.

Means for Solving the Problems

[0006] In view of the above problems, the present invention provides a flame-retardant water-based paint composition containing (A) a water-based binder resin and (B) a non-halogen-based water-soluble synthetic polymer flame retardant (Invention 1).

[0007] According to this invention (Invention 1), by blending a non-halogen-based water-soluble synthetic polymer flame retardant with a water-based binder resin, a coating film with excellent flame retardancy can be obtained, thereby imparting flame retardancy to buildings and building materials.

[0008] In the above invention (Invention 1), it is preferable to further contain (C) an inorganic layered compound (Invention 2). In the above invention (Invention 2), the (C) inorganic layered compound is at least one compound selected from non-swelling layered silicates and swelling layered silicates (Invention 3). In the above invention (Invention 3), it is preferable that the inorganic layered compound has an aspect ratio of 10 to 1000 (Invention 4).

[0009] According to these inventions (Inventions 2-4), by further incorporating an inorganic layered compound, the water vapor permeability resistance of the coating film is improved, thereby enhancing its moisture resistance. In addition, it exhibits an excellent shielding effect against flammable and toxic gases generated during the combustion of the coated object, effectively preventing the spread of fire and gas poisoning caused by toxic gases.

[0010] In the above invention (Invention 1), it is preferable that the component of (B) non-halogenated water-soluble synthetic polymer flame retardant is a thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof (Invention 5). In particular, in the above invention (Invention 5), it is preferable that the thermally depolymerizable polymer having a structure to which the water-soluble functional group is attached has a structure represented by the following chemical formula (Invention 6). [ka] (In the formula, X is hydrogen (H) or an alkyl group having 1 to 3 carbon atoms, and Y is COOH, SO3H, OCOOH, OSO3H, COO(CH2))m COOH, COO(CH2) m SO3H, benzene ring-COOH, or benzene ring-SO3H, where n is a positive integer between 5 and 27,000, and m is a positive integer between 1 and 5.

[0011] According to the inventions described above (inventions 5 and 6), by using a non-halogenated water-soluble synthetic polymer flame retardant as a thermally depolymerizable polymer having a structure to which water-soluble functional groups are attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof, and in particular a thermally depolymerizable polymer having a structure to which water-soluble functional groups having a specific structure are attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof, a paint with excellent flame retardancy can be obtained.

[0012] In the above invention (Invention 1), it is preferable that the (A) aqueous binder resin is an acrylic resin and is used in the form of an emulsion (Invention 7). In the above invention (Invention 7), it is preferable that the acrylic resin is an acrylic silicone resin (Invention 8). In the above invention (Invention 7), it is preferable that the acrylic resin has a glass transition temperature of 30 to 60°C (Invention 9).

[0013] According to these inventions (Inventions 7-9), the properties of the paint, such as applicability and handling, can be exhibited well.

[0014] The above invention (Invention 1) may further contain a silane coupling agent (Invention 10).

[0015] According to this invention (Invention 10), by using a silane coupling agent, it is possible to create a paint that forms a coating film with increased crosslinking density and improved water resistance.

[0016] In the above invention (Invention 5), it is preferable that the (B) non-halogenated water-soluble synthetic polymer flame retardant is an alkali metal salt of a thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, and that the alkali metal salt is a K salt or a Na salt (Invention 11). In the above invention (Invention 5), it is preferable that the (B) non-halogenated water-soluble synthetic polymer flame retardant is an alkaline earth metal salt of a thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, and that the alkaline earth metal salt is a Ca salt or a Mg salt (Invention 12). In the above invention (Invention 5), it is preferable that the content of the thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, its alkali metal salt, or its alkaline earth metal salt is 0.1 to 20% by weight (Invention 13). In the above invention (Invention 5), it is preferable that the weight-average molecular weight (MW) of the thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, its alkali metal salt, or its alkaline earth metal salt is 1,000,000 or less (Invention 14). Furthermore, in the above invention (Invention 5), the (B) non-halogenated water-soluble synthetic polymer flame retardant may contain two or more types of thermally depolymerizable polymers having a structure to which water-soluble functional groups are attached, alkali metal salts thereof, or alkaline earth metal salts thereof (Invention 15).

[0017] According to the inventions described above (inventions 11 to 15), by including a predetermined amount of a non-halogenated water-soluble synthetic polymer flame retardant having a structure to which a water-soluble functional group is attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof, and in particular a thermodepolymer having a structure to which a water-soluble functional group having a specific structure is attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof having predetermined properties, a paint with excellent flame retardancy can be made.

[0018] In the above inventions (Inventions 5, 6, 11-15), it is preferable that the pyropolymer with the structure to which the water-soluble functional group is attached is poly(methacrylic acid) (Invention 16).

[0019] According to such an invention (Invention 16), by using a non-halogen-based water-soluble synthetic polymer flame retardant as poly(methacrylic acid), its alkali metal salt, or its alkaline earth metal salt, a paint with high versatility and excellent flame retardancy can be obtained.

Advantages of the Invention

[0020] According to the flame-retardant aqueous paint composition of the present invention, since a non-halogen-based water-soluble synthetic polymer flame retardant is blended with an aqueous binder resin, it is a flame-retardant aqueous paint composition capable of forming a paint film with good flame retardancy on buildings, building materials, etc. Further, by using this flame-retardant aqueous paint composition, a paint film with good flame retardancy and a building board provided with the paint film can be provided.

Embodiments for Carrying Out the Invention

[0021] Based on the following embodiments, the flame-retardant aqueous paint composition of the present invention will be described in detail. The flame-retardant aqueous paint composition of this embodiment is characterized by containing (A) an aqueous binder resin and (B) a non-halogen-based water-soluble synthetic polymer flame retardant. Note that the aqueous paint composition in this embodiment refers to a paint composition using water as the main solvent. Specifically, it is a paint composition in which the water content in the solvent component of the aqueous paint composition is 50% by mass or more. The water content in the solvent component of the aqueous paint composition is preferably 90% by mass or more.

[0022] (A) Aqueous binder resin The aqueous binder resin that can be used in the flame-retardant aqueous paint composition of this embodiment is a water-soluble resin that dissolves in water or a synthetic resin that can be dispersed in water, and it may be used in either the form of a solution or an emulsion. However, from the viewpoint of water resistance, it is preferably used in the form of an emulsion. Note that a synthetic resin in a dispersed state in water is also referred to as a "synthetic resin emulsion."

[0023] Examples of the water-soluble resins mentioned above include acrylic resins, silicone resins, acrylic silicone resins, fluororesins, epoxy resins, vinyl resins, phenolic resins, urethane resins, melamine resins, and ketone resins. These resins may be used individually or in combination of two or more. Furthermore, these resins may be modified with other resin components. In addition, crosslinking agents may be added to these water-soluble resins.

[0024] Examples of the above-mentioned synthetic resin emulsions include acrylic resin emulsions, urethane resin emulsions, fluororesin emulsions, polystyrene resin emulsions, and vinyl chloride resin emulsions, but acrylic resin emulsions are preferred in terms of weather resistance and ease of handling. Crosslinking agents may also be added to these synthetic resin emulsions. Here, acrylic resin emulsion means an emulsion of a polymer of (meth)acrylic monomer or an emulsion of a copolymer of (meth)acrylic monomer and other monomers.

[0025] The above-mentioned synthetic resin emulsions can be prepared using conventional synthesis methods that are already known. For example, in the case of acrylic resin emulsions, they can be obtained by emulsion polymerization in water under stirring in the presence of an emulsifier or dispersion stabilizer, using a (meth)acrylic monomer containing at least one of acrylic acid esters and methacrylic acid esters, and other monomers as needed. Furthermore, after preparation, the synthetic resin emulsion may be neutralized as needed, or the synthetic resin contained in the synthetic resin emulsion may be modified.

[0026] Examples of (meth)acrylic monomers that can be used in the preparation of acrylic resin emulsions include: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and other C1-C18 alkyl or cycloalkyl esters of acrylic acid or methacrylic acid; methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxybutyl (meth)acrylate, and other C2-C18 alkoxyalkyl esters of acrylic acid or methacrylic acid; acrylic acid, methacrylic acid, crotonic acid, Examples of monomers include carboxyl group-containing unsaturated monomers such as itaconic acid, maleic acid, and fumaric acid; hydroxyalkyl esters of acrylic acid or methacrylic acid having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate and 2- or 3-hydroxypropyl (meth)acrylate; nitrogen-containing alkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate; polymerizable amides such as acrylamide, methacrylamide, N-butoxymethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, and N,N-dimethylaminoethyl (meth)acrylamide; and epoxy acrylates such as glycidyl (meth)acrylate. Examples of monomers other than (meth)acrylic monomers include epoxy group-containing unsaturated monomers such as allyl glycidyl ether, vinyl acetate, styrene, and acrylonitrile. Furthermore, if the acrylic resin emulsion is an emulsion of a copolymer of (meth)acrylic monomer and other monomers, and the other monomers include at least styrene, the proportion of styrene in the total monomers constituting the copolymer is preferably 50% by mass or more, and more preferably in the range of 50 to 98% by mass.When the proportion of styrene is 50% by mass or more, the water vapor permeability resistance of the coating film tends to be good.

[0027] Emulsion polymerization reactions are carried out, for example, by supplying monomers and polymerization initiators together or continuously in an aqueous medium at a predetermined temperature under stirring in the presence of an emulsifier.

[0028] Examples of the emulsifiers mentioned above include fatty acid salts such as sodium laurate, higher alcohol sulfate esters such as sodium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, polyoxyethylene alkyl ether sulfates, polyoxynonylphenyl ethersulfonate ammonium, polyoxyethylene-polyoxypropylene glycol ether sulfates, and anionic surfactants such as so-called reactive emulsifiers having a polymerizable carbon-carbon unsaturated double bond in the molecule with a sulfonic acid group or sulfate ester group; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene nonylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene-polyoxypropylene block copolymers, or reactive nonionic surfactants having a polymerizable carbon-carbon unsaturated double bond in the molecule with the skeleton of these compounds; cationic surfactants such as alkylamine salts and quaternary ammonium salts; and (modified) polyvinyl alcohol.

[0029] Furthermore, polymerization initiators that can be used in emulsion polymerization reactions include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; azo compounds such as 2,2'-azobis(2-aminodipropane) hydrochloride, 4,4'-azobis-cyanovaleric acid, and 2,2'-azobis(2-methylbutanamide oxime) dihydrochloride tetrahydrate; aqueous radical polymerization initiators such as t-butyl hydroperoxide; and mixtures thereof. Such polymerization initiators can be combined with reducing agents to form redox polymerization initiators. Such reducing agents include alkali metal salts such as sulfites, bisulfites, pyrosulfites, sodium thiosulfate, and formaldehyde sulfonates, as well as carboxylic acids such as ammonium salts, L-ascorbic acid, and tartaric acid.

[0030] Chain transfer agents can be used in emulsion polymerization reactions as needed. Examples of such chain transfer agents include alkyl mercaptans such as lauryl mercaptan, n-butyl mercaptan, t-butyl mercaptan, octyl mercaptan, and n-dodecyl mercaptan, 2-ethylhexyl thioglycolate, 2-methyl-t-butylthiophenol, and α-methylstyrene dimer.

[0031] In the flame-retardant water-based paint composition of this embodiment, when the water-based binder resin is an acrylic resin, the glass transition temperature (hereinafter also referred to as Tg) of the acrylic resin is preferably 30 to 60°C. If Tg is less than 30°C, the paint film will soften with the ambient temperature, and the paint film will become contaminated due to stickiness and adhesion of contaminants, making it unsuitable. On the other hand, if Tg exceeds 60°C, when the paint film is cured, it will not be able to follow the expansion of the object to be coated, such as building materials, and peeling of the paint film will be more likely to occur. When using an acrylic resin emulsion, it is preferable to combine ethylenically unsaturated monomers so that the Tg of the acrylic resin is 30 to 60°C. Note that the value of Tg refers to the value calculated using the commonly used FOX formula.

[0032] In the flame-retardant water-based paint composition of this embodiment, when the water-based binder resin is an acrylic resin, the acid value of the acrylic resin is preferably 15 mg KOH / g or higher, and more preferably 15 to 100 mg KOH / g. When the acid value is 15 mg KOH / g or higher, the water vapor permeability resistance of the coating film tends to be good. On the other hand, when the acid value exceeds 100 mg KOH / g, the water resistance of the coating film tends to deteriorate.

[0033] Among the above acrylic resin emulsions, from the viewpoint of blocking resistance, an acrylic silicone resin emulsion that can be obtained by copolymerizing at least a (meth)acrylic monomer with a monomer having a hydrolyzable silyl group is preferred. Examples of monomers having a hydrolyzable silyl group include γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, β-(meth)acryloxyethyltrimethoxysilane, β-(meth)acryloxyethyltriethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropylmethyldipropoxysilane, γ-(meth)acryloxybutylphenyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, and γ-(meth)acryloxypropyldiethylmethoxysilane.

[0034] In the polymerization of the above-mentioned acrylic silicone resin, the amount of monomers having hydrolyzable silyl groups is preferably 0.2% by mass or more and 15.0% by mass or less of the total amount of monomers used, more preferably 0.5% by mass or more and 12.0% by mass or less, and even more preferably 0.5% by mass to 3% by mass. If the amount of monomers having hydrolyzable silyl groups is less than 0.2% by mass, sufficient blocking resistance may not be obtained, and if it exceeds 15.0% by mass, the film tends to become brittle.

[0035] (B) Non-halogenated water-soluble synthetic polymer flame retardants As non-halogenated water-soluble synthetic polymer flame retardants that can be used in the flame-retardant water-based paint composition of this embodiment, a thermally depolymerizable polymer having a structure to which water-soluble functional groups are attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof (hereinafter, these may be collectively referred to as the thermally depolymerizable polymer component) can be suitably used.

[0036] The thermally depolymerizable polymer with this water-soluble functional group is preferably structured as shown in the following chemical formula.

[0037] [ka]

[0038] (In the formula, X is hydrogen (H) or an alkyl group having 1 to 3 carbon atoms, Y is COOH, SO3H, OCOOH, OSO3H, COO(CH2)mCOOH, COO(CH2)mSO3H, benzene ring-COOH, or benzene ring-SO3H, n is a positive integer between 5 and 27,000, and m is a positive integer between 1 and 5.)

[0039] Poly(methacrylic acid) can be suitably used as a thermally depolymerizable polymer with such a water-soluble functional group structure.

[0040] Furthermore, as alkali metal salts of thermally depolymerizable polymers with water-soluble functional groups, sodium (Na) salts, potassium (K) salts, etc., can be used. In addition, as alkaline earth metal salts, calcium (Ca) salts, magnesium (Mg) salts, etc., can be used.

[0041] These polymer components are preferably those with a weight-average molecular weight (MW) of 1,000,000 or less, and particularly preferably 100,000 or less. Those with a weight-average molecular weight (MW) exceeding 1,000,000 not only have reduced solubility in water but also decrease the efficiency of polymer production. While there are no particular restrictions on the lower limit of the weight-average molecular weight (MW) as long as it is in polymer form, it should be 500 or more, and particularly 1,000 or more.

[0042] This pyropolymerizable polymer component may be a pyropolymer with a structure to which a water-soluble functional group has been added, an alkali metal salt thereof, or an alkaline earth metal salt thereof, each used individually or in combination of two or more.

[0043] The content of the aforementioned (B) non-halogenated water-soluble synthetic polymer flame retardant, particularly a thermally depolymerizable polymer with a structure to which water-soluble functional groups are attached, its alkali metal salt, or its alkaline earth metal salt, is 0.1 to 20% by weight (on a solid content basis), with (A) + (B) + water being 100% by weight. If the non-halogenated water-soluble synthetic polymer flame retardant is less than 0.1% by weight, a sufficiently flame-retardant coating cannot be formed. On the other hand, if it exceeds 20% by weight, not only is no further improvement in effectiveness not expected, but the handlingability of the paint also deteriorates.

[0044] (C) Inorganic layered compounds The flame-retardant water-based paint composition of this embodiment preferably further contains an inorganic layered compound. The inorganic layered compound is an inorganic compound having a layered structure in which crystalline layers are stacked on top of each other. When a paint film is formed, the inorganic layered compounds in the paint composition overlap and laminate each other, exhibiting the effect of improving the water vapor permeability resistance of the paint film and improving moisture resistance. In addition, it exhibits an excellent shielding effect against flammable gases and toxic gases generated when the object to be painted is burned, and effectively acts against the spread of fire and gas poisoning caused by toxic gases.

[0045] The inorganic layered compound described above is a compound having a layered structure in which unit crystal layers are stacked on top of each other. Here, a layered structure refers to a structure in which surfaces (layers) in which atoms are strongly bonded by covalent bonds or the like and densely arranged are stacked in parallel by weak bonding forces such as van der Waals forces. The inorganic layered compound has cleavage properties, and the inorganic layered compound that can be used in this embodiment preferably has a particle size of 5 to 60 μm, and an aspect ratio (major axis / thickness) of 10 to 5000. When the particle size and / or aspect ratio are within the specified range, it can exhibit an excellent effect on improving the water vapor permeability resistance and can also improve the shielding effect. If the aspect ratio of the inorganic layered compound is less than 10, sufficient water vapor permeability resistance may not be obtained, and if the aspect ratio exceeds 5000, the dispersion stability of the coating decreases. Furthermore, an aspect ratio of 10 to 1000 is even more preferable. When the aspect ratio is within the range of 10 to 1000, the freeze-thaw stability of the coating film is further improved, and the coating film is less prone to cracking even under conditions of large temperature fluctuations. The particle size of the inorganic layered compound can be measured using general methods such as laser diffraction. The aspect ratio can be determined using a scanning electron microscope (SEM). Specifically, one method involves observing the inorganic layered compound with an SEM, measuring the major axis and thickness of 50 to 100 randomly extracted inorganic layered compound particles, determining the aspect ratio of each particle, and then calculating the average value.

[0046] Specific examples of the above inorganic layered compounds include layered silicates, layered graphite, layered chalcogenides, layered hydrotalcite compounds, layered lithium aluminum complex hydroxides, and layered zirconium phosphate compounds. However, layered silicates are preferred in terms of water resistance, durability, and ease of handling. Here, "chalcogenide" refers to a dichalcogenide of group IV (Ti, Zr, Hf), group V (V, Nb, Ta), and / or group VI (Mo, W) elements, represented by the formula MX2 (where M is the above element and X is chalcogen (S, Se, Te)).

[0047] The above-mentioned layered silicates are generally classified into types such as a two-layer structure (1:1 type structure) having an octahedral layer with aluminum or magnesium as the central metal on top of a tetrahedral layer of silica, and a three-layer structure (2:1 type structure) in which a tetrahedral layer of silica sandwiches an octahedral layer with aluminum or magnesium as the central metal on both sides.

[0048] Examples of layered silicates with a 1:1 structure include kaolinite and halloysite, which are kaolin minerals.

[0049] Layered silicates with a 2:1 structure are classified according to differences in layer charge. For example, talc and pyrophyllite have almost no layer charge, while those with layer charge include the smectite group (saponite, heracleite, montmorillonite, etc.), vermiculite, and the mica group (phlogopite, muscovite, sericite, etc.).

[0050] The layered silicates mentioned above include not only naturally occurring products but also synthetic products obtained through artificial synthesis. Examples of synthetic products include synthetic micas such as fluorinated phlogopite (KMg3AlSi3O10F), potassium tetrasilicate (KMg2.5Si4O10F2), sodium tetrasilicate (NaMg2.5Si4O10F2), sodium teniolite (NaMg2LiSi4O10F2), and lithium teniolite (LiMg2LiSi4O10F2), as well as synthetic smectites such as sodium hectorite (Na0.33Mg2.67Li0.33Si4.0O10(OH or F)2), lithium hectorite (Li0.33Mg2.67Li0.33Si4.0O10(OH or F)2), and saponite (Na0.33Mg2.67AlSi4.0O10(OH)2). In this embodiment, natural products and synthetic products may be used individually or in combination.

[0051] The layered silicates described above include swellable layered silicates, which, upon contact with water, adsorb water molecules between the crystalline layers, swell, cleave, and disperse in water, and non-swellable layered silicates, which remain unchanged upon contact with water. In the flame-retardant water-based paint composition of this embodiment, when a swellable layered silicate is used as the inorganic layered compound, the inorganic layered compound exhibits good dispersibility and is less prone to settling, resulting in good paintability.

[0052] Examples of swollen layered silicates include halloysite and smectite from natural sources, and the aforementioned synthetic mica or synthetic smectite from synthetic sources.

[0053] In the flame-retardant water-based coating composition of this embodiment, the amount of inorganic layered compound blended is preferably 2 to 200 parts by mass per 100 parts by weight of (A) + (B).

[0054] (D) Silane coupling agent The flame-retardant water-based coating composition of this embodiment preferably further contains a silane coupling agent. Using a silane coupling agent tends to increase the crosslinking density and improve water resistance. Any known silane coupling agent can be used without limitation. The amount of silane coupling agent is preferably 0.3 to 5 parts by mass per 100 parts by weight of (A) + (B). If the amount of silane coupling agent is less than 0.3 parts by mass, the effect of adding the silane coupling agent is difficult to obtain, while if it exceeds 5 parts by mass, the coating film tends to crack easily.

[0055] In addition to the components mentioned above, the flame-retardant water-based paint composition of this embodiment may contain known paint additives as appropriate, provided they do not affect the present invention. Typical examples include pigments, wetting agents, dispersants, emulsifiers, thickeners, anti-settling agents, anti-skinning agents, anti-sagging agents, defoaming agents, anti-color separation agents, leveling agents, drying agents, plasticizers, antifungal agents, antibacterial agents, insecticides, preservatives, light stabilizers, ultraviolet absorbers, antistatic agents, and conductivity imparters. Examples of pigments include coloring pigments, extender pigments, and metal powder pigments, which are selected and used as appropriate depending on the coloring, gloss, paintability, strength, and physical properties of the paint film.

[0056] The flame-retardant water-based paint composition of this embodiment can be prepared by mixing the above-mentioned water-based binder resin and non-halogenated water-soluble synthetic polymer flame retardant with water, along with various components as needed. However, the flame-retardant water-based paint composition of this embodiment may also be a mixed type, prepared by separating the components used into a main agent and a hardener, and mixing the main agent and hardener immediately before use. In the case of a mixed type, mixing is performed at room temperature, and a mixer can be used as appropriate.

[0057] Furthermore, the flame-retardant water-based paint composition of this embodiment is preferably applied as a sealer, particularly as a primer, which reliably improves flame retardancy. [Examples]

[0058] The present invention will be described in more detail below with reference to examples and comparative examples. The tests were conducted according to the paints and test methods shown below.

[0059] 1-1. Preparation of water-based paint for testing Kanpe Hapio Co., Ltd. prepared a "Water-based Wood Protective Paint" (containing acrylic resin as a water-based binder resin). To this paint, a 20% by weight aqueous solution of polypotassium methacrylate (molecular weight 230,000) as a flame retardant was added in the proportions shown in Table 1 to prepare a test paint.

[0060] [Table 1]

[0061] 1-2 Preparation of wood test specimens for fire resistance testing Test specimens were prepared by applying 1g each of paints A, B, and C to a 10cm x 10cm x 1cm cypress board using a roller brush and drying them at room temperature (25°C) for 12 hours. Table 2 shows the test paints, the amount of paint applied, the amount of paint remaining after drying, and the amount of flame retardant solids in each test specimen.

[0062] [Table 2]

[0063] 1-3 Results of fire resistance tests of test specimens using a gas burner Each test specimen was positioned 15 cm from the tip of the gas burner nozzle, with a 10 cm x 10 cm surface of the specimen perpendicular to the gas burner flame. The flame was then applied for 10 seconds. The time from the start of application of the gas burner flame to the specimen until black charring was observed, and the area of ​​black charring on the specimen after 10 seconds were compared. The results are shown in Table 3.

[0064] [Table 3]

[0065] As is clear from Table 3, the test pieces coated with paint containing the flame retardant (polypotassium methacrylate) used in this test (Examples 1 and 2) showed a delay in the time it took to burn and a reduction in the burned area compared to test pieces without the flame retardant (Comparative Example 1 and Comparative Example 2). It was also found that the higher the amount of flame retardant added to the paint, the better this fire-resistant effect was.

Claims

1. A flame-retardant water-based paint composition comprising (A) a water-based binder resin and (B) a non-halogen-based water-soluble synthetic polymer flame retardant.

2. The flame-retardant water-based paint composition according to claim 1, further comprising (C) an inorganic layered compound.

3. The flame-retardant water-based paint composition according to claim 2, wherein the (C) inorganic layered compound is at least one compound selected from non-swelling layered silicates and swelling layered silicates.

4. The flame-retardant water-based paint composition according to claim 3, wherein the inorganic layered compound has an aspect ratio of 10 to 1000.

5. The flame-retardant water-based paint composition according to claim 1, wherein the component of (B) non-halogenated water-soluble synthetic polymer flame retardant is a thermally depolymerizable polymer having a structure to which water-soluble functional groups are attached, an alkali metal salt thereof, or an alkaline earth metal salt thereof.

6. The flame-retardant water-based paint composition according to claim 5, wherein the thermally depolymerizable polymer having the water-soluble functional group has the structure shown by the following chemical formula. 【Chemistry 1】 (In the formula, X is hydrogen (H) or an alkyl group having 1 to 3 carbon atoms, and Y is COOH or SO ３ H, OCOOH, OSO ３ H, COO (CH2) ｍ COOH, COO(CH2) ｍ SO ３ H, benzene ring-COOH or benzene ring-SO ３ H is a positive integer between 5 and 27,000, and m is a positive integer between 1 and 5.

7. The flame-retardant water-based paint composition according to claim 1, wherein the (A) water-based binder resin is an acrylic resin and is used in the form of an emulsion.

8. The flame-retardant water-based paint composition according to claim 7, wherein the acrylic resin is an acrylic silicone resin.

9. The flame-retardant water-based paint composition according to claim 7, wherein the acrylic resin has a glass transition temperature of 30 to 60°C.

10. Furthermore, the flame-retardant water-based paint composition according to claim 1, comprising a silane coupling agent.

11. The flame-retardant water-based paint composition according to claim 5, wherein the (B) non-halogenated water-soluble synthetic polymer flame retardant is an alkali metal salt of a thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, and the alkali metal salt is a K salt or a Na salt.

12. The flame-retardant water-based paint composition according to claim 5, wherein the (B) non-halogenated water-soluble synthetic polymer flame retardant is an alkaline earth metal salt of a thermally depolymerizable polymer having a structure to which a water-soluble functional group is attached, and the alkaline earth metal salt is a Ca salt or a Mg salt.

13. The flame-retardant water-based paint composition according to claim 5, wherein the content of the thermally depolymerizable polymer having the water-soluble functional group, its alkali metal salt, or its alkaline earth metal salt is 0.1 to 20% by weight.

14. The flame-retardant water-based paint composition according to claim 5, wherein the weight-average molecular weight (MW) of the thermally depolymerizable polymer having the structure to which the water-soluble functional group is attached, the alkali metal salt thereof, or the alkaline earth metal salt thereof is 1,000,000 or less.

15. The flame-retardant water-based paint composition according to claim 5, wherein the (B) non-halogenated water-soluble synthetic polymer flame retardant contains two or more thermally depolymerizable polymers having a structure to which water-soluble functional groups are attached, alkali metal salts thereof, or alkaline earth metal salts thereof.

16. The flame-retardant water-based paint composition according to any one of claims 5, 6, 11 to 15, wherein the thermally depolymerizable polymer having the water-soluble functional group is poly(methacrylic acid).

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