Coating composition and coated article

Abstract

A coating composition is provided comprising: (i) an organopolysiloxane in a unit ratio shown in formula (1) below, and (ii) an inorganic filler. (R) 1 ~R 3 R represents an alkyl group, such as an alkyl group that may have an ether bond and may be substituted with one or more hydroxyl groups, at least part of which is an alkyl group that is substituted with a hydroxyl group and may have an ether bond. 4 Representing a hydrogen atom or alkyl group, where a is 0–0.5, b is 0–0.5, c is 0.2–1.0, d is 0–0.5, e is 0–3.0, and is a number satisfying a+b+c+d=1.

Description

TECHNICAL FIELD

[0001] The present application relates to a coating composition and a coated article, and more particularly to a flame-retardant coating composition and a coated article for wood-based materials. BACKGROUND

[0002] In recent years, from the viewpoint of carbon fixation and effective use of domestic resources, the use of wood in buildings is being promoted, and wood is a flammable base material, so the use thereof in applications requiring flame retardancy is greatly limited.

[0003] In this case, various techniques for imparting flame retardancy to wood are being studied.

[0004] For example, in Patent Literature 1, by impregnating a flame retardant such as boric acid into wood at a high concentration, flame retardancy is successfully imparted. However, in this system, the flame retardant adsorbed to the wood is dissolved or deliquesced in the moisture in the air, and this greatly deteriorates the appearance, which is a problem.

[0005] In Patent Literature 2, it is reported that by coating a siloxane compound on the surface of wood after impregnating a boron compound into the wood, the elution of the agent can be suppressed. However, in the case where this method is used, the boron compound is dissolved in the moisture contained in the wood itself, and cases of occurrence of white spots at the interface between the coating film and the wood are reported. In addition, in this method, a large number of processes such as impregnation of the flame retardant, drying, and surface coating are required, and an increase in manufacturing cost is inevitable.

[0006] In Patent Literature 3, a technique is reported in which a primer component containing silica as a main component is coated on the surface of wood, and water glass is coated thereon, thereby imparting flame retardancy to the wood without impregnating a flame retardant into the wood. On the other hand, water glass has low curability and water resistance, and in addition, discoloration problems due to reaction with wood are known, and there are many issues for practical use.

[0007] In addition, when coating is performed on the surface of wood, since a part of the coating liquid is absorbed into the inside of the wood, the powder additives such as pigments and fillers are segregated on the surface, and sometimes appearance defects such as white spots and discoloration occur. Such appearance defects easily occur particularly around knots where fibers are sparse. In general, in order to suppress the absorption of the coating into the wood, a middle coat layer called a sealer is provided, but in the sealer coating, in order to improve film formation, an organic polymer is generally used, and the flame retardancy of the wood deteriorates.

[0008] PRIOR ART DOCUMENTS

[0009] PATENT LITERATURE

[0010] Patent Literature 1: Japanese Patent No. 3538194

[0011] Patent Document 2: Japanese Patent No. 4367640

[0012] Patent Document 3: Japanese Patent Application Publication No. 2018-115294 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] The present invention was made in view of the above-mentioned circumstances, and aims to provide a coating composition that maintains the appearance of wood such as wood grain and can impart excellent flame retardancy and moisture resistance, and articles covered therewith.

[0015] Methods for solving problems

[0016] In order to achieve the above objectives, the inventors conducted in-depth research and found that the above objectives could be achieved by using a coating composition containing a specified hydroxyl-modified organopolysiloxane and an inorganic filler, thus completing the present invention.

[0017] That is, the present invention provides:

[0018] 1. A coating composition comprising:

[0019] (i) an organopolysiloxane composed of units in the ratio shown in formula (1) below: 100 parts by mass, and

[0020]

[0021] (where R) 1 R 2 and R 3 Each group independently represents a hydrogen atom, or may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups, and may have an ether bond; it may be an alkyl group with 1 to 20 carbon atoms, an aryl group with 6 to 20 carbon atoms, or an aralkyl group with 7 to 20 carbon atoms. 1 R 2 and R 3 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, an aryl group having 6 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, or an aralkyl group having 7 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, R 4 Each of the following independently represents an alkyl group having 1 to 8 hydrogen or carbon atoms, where a is 0 to 0.5, b is 0 to 0.5, c is 0.2 to 1.0, d is 0 to 0.5, e is 0 to 3.0, and is a number satisfying a + b + c + d = 1.

[0022] (ii) Inorganic fillers: 100-900 parts by weight;

[0023] 2. The coating composition according to claim 1, wherein the R 1 R 2 and R 3 The total number of hydroxyl groups contained therein is more than 50 mol% relative to the total number of silicon atoms in formula (1);

[0024] 3. The coating composition according to 1 or 2, wherein the (ii) inorganic filler comprises one or more selected from silica, alumina, and layered silicates;

[0025] 4. The coating composition according to any one of 1 to 3, wherein, relative to 100 parts by mass of component (i), it further comprises 10 to 300 parts by mass of (iii) one or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based and halogen-based compounds;

[0026] 5. The coating composition according to 4, wherein the ratio of the total mass of component (ii) and component (iii) to the mass of component (i) [(ii) + (iii)] / (i) is 2.0 to 9.0;

[0027] 6. The cured product of the coating composition according to any one of claims 1 to 5;

[0028] 7. A coated article, wherein at least a portion of the surface of a wood substrate has a coating layer consisting of a coating film made of a coating composition according to any one of 1 to 5, either directly or indirectly through one or more other layers;

[0029] 8. A coated article, wherein at least a portion of the surface of a wood substrate is provided with a base coat consisting of a coating film made of a coating composition according to any one of 1 to 5, and a top coat consisting of a coating film made of a top coat coating composition comprising component (A), component (B), and component (C).

[0030] (A) Organopolysiloxanes composed of unit ratios expressed by the following formula (2): 100 parts by mass

[0031]

[0032] (where R) 5 R 6 and R 7 Each of the following groups independently represents a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, which may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups. 5 R 6 and R7 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms substituted with an amino group, an aryl group having 6 to 20 carbon atoms substituted with an amino group, or an aralkyl group having 7 to 20 carbon atoms substituted with an amino group, R 8 Each of the following independently represents an alkyl group having 1 to 8 hydrogen or carbon atoms, where f is 0 to 0.5, g is 0 to 0.5, h is 0.2 to 1.0, i is 0 to 0.5, j is 0 to 3.0, and the number satisfies f + g + h + i = 1.

[0033] (B) One or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based, and halogen-based compounds: 50 to 300 parts by weight, and

[0034] (C) Inorganic filler: 25-150 parts by weight;

[0035] 9. The coated article according to claim 8, wherein the coating amount of the primer is 0.01 to 0.50 kg / m² relative to the wood substrate. 2 The coating thickness relative to the wood substrate is 0.1–2.0 kg / m². 2 .

[0036] The effects of the invention

[0037] When the coating composition of the present invention is used as a primer coating for wood substrates, the organic polysiloxane and inorganic filler effectively cover the gaps between wood fibers, thereby improving moisture resistance. By inhibiting the absorption of the topcoat coating on the surface of the wood substrate, it is possible to suppress appearance deterioration such as whitening around knots.

[0038] Furthermore, by combining it with a topcoat containing organopolysiloxanes, flame retardants, and inorganic fillers, the coating is ceramicized during combustion, forming a refractory layer and / or an insulating layer that can prevent the wood substrate from burning.

[0039] Utilizing these effects, the present invention can provide coverings that maintain the appearance of wood-based substrates such as wood grain, which were previously difficult to preserve, and that exhibit excellent flame retardancy and moisture resistance.

[0040] The coating composition of the present invention imparts flame retardancy to a wood substrate by applying it to the surface, offering a simpler method compared to conventional methods involving impregnation with flame retardants. Furthermore, flame retardancy can also be achieved through on-site application, significantly expanding the design and / or construction freedom of wooden buildings. Detailed Implementation

[0041] The present invention will now be described in detail.

[0042] [1] Coating composition

[0043] The coating composition of the present invention comprises the following components (i) and (ii).

[0044] (i) Organopolysiloxanes composed of the unit ratio shown in formula (1) below

[0045] (ii) Inorganic packing

[0046] (i) Organopolysiloxane

[0047] (i) The composition is an organopolysiloxane consisting of units in the ratio shown in formula (1) below. It should be noted that, unless otherwise specified, in formula (1) below, (R... 1 3SiO 1 / 2 The element shown is called the M-element, and (R) 2 The unit shown in 2SiO is called a D unit, and (R) 3 SiO 3 / 2 The unit shown in () is called the T unit, and the unit shown in (SiO2) is called the Q unit.

[0048]

[0049] In equation (1), R 1 R 2 and R 3 Each of these R groups independently represents a hydrogen atom, or may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups, and may have an ether bond; and may be an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 1 R 2 and R 3 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms that can be substituted with a hydroxyl group and have an ether bond, an aryl group having 6 to 20 carbon atoms that can be substituted with a hydroxyl group and have an ether bond, or an aralkyl group having 7 to 20 carbon atoms that can be substituted with a hydroxyl group and have an ether bond.

[0050] The alkyl group having 1 to 20 carbon atoms can be straight-chain, branched, or cyclic. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, cyclopentyl, and cyclohexyl. From the perspective of improving the flame retardancy of the coating composition, methyl or ethyl is preferred.

[0051] Examples of aryl groups with 6 to 20 carbon atoms include phenyl and naphthyl groups.

[0052] Aryl groups with 7 to 20 carbon atoms include benzyl and phenethyl.

[0053] Examples of heterocyclic groups include piperidinyl, pyridinyl, pyrroleyl, and thiopheneyl.

[0054] As mentioned above, in equation (1), R 1 R 2 and R 3 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms that is substituted with a hydroxyl group and may have an ether bond, an aryl group having 6 to 20 carbon atoms that is substituted with a hydroxyl group and may have an ether bond, or an aralkyl group having 7 to 20 carbon atoms that is substituted with a hydroxyl group and may have an ether bond. Preferably, such a hydroxy-substituted group is 2-hydroxyethyl, 3-hydroxypropyl, 2,3-dihydroxypropyl, 3,4-dihydroxybutyl, β-(3,4-dihydroxycyclohexyl)ethyl, or a group represented by the following formula (3).

[0055] [Chemistry 1]

[0056]

[0057] (In the formula, the line with a wavy line represents the joint end.)

[0058] If we consider the solubility of component (i) in water, its affinity with inorganic filler components and substrate, etc., R 1 R 2 and R 3 The total number of hydroxyl groups contained therein is preferably 50 mol% or more, more preferably 80 mol% or more, and even more preferably 100 mol% or more, relative to the total number of silicon atoms in formula (1).

[0059] Furthermore, R 1 R 2 and R 3 In this context, the substituents other than the hydroxyl-substituted group are preferably methyl or ethyl groups with a low number of carbon atoms in a flammable alkyl chain, and more preferably methyl.

[0060] In equation (1), R 4 Each can be independently represented as an alkyl group having 1 to 8 hydrogen atoms or carbon atoms.

[0061] Specific examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, etc.

[0062] Of these, from the perspective of the flame retardancy of the coating composition, R 4 Hydrogen atoms are preferred.

[0063] A number in which a is 0 to 0.5, b is 0 to 0.5, c is 0.2 to 1.0, d is 0 to 0.5, and a + b + c + d = 1.

[0064] From the viewpoint of the water solubility of organopolysiloxanes, a value of e between 0 and 3.0 is preferred, and a value between 0.1 and 2.0 is preferred. If e exceeds 3.0, the film-forming properties and moisture resistance of the coating composition may deteriorate.

[0065] (i) The organopolysiloxane component is condensed to some extent, so network formation becomes easy and it is easy to fix to the substrate. In addition, the alkoxy group, which is the source of flammable gas, is less than that of monomers (silane coupling agents, etc.) that do not contain siloxane bonds (Si-O-Si bonds), thus having the advantage of less reduction in flame retardancy.

[0066] The monomer component without siloxane bonds mentioned above is preferably 50% or less by mass, more preferably 30% or less by mass, even more preferably 10% or less by mass, and even more preferably 1% or less by mass relative to the organopolysiloxane of component (i).

[0067] The ratio of the monomer component without siloxane bonds to the organopolysiloxane component can be determined by... 29 The signal and integral ratio in the Si-NMR (nuclear magnetic resonance) spectrum are obtained. 29 In Si-NMR, for example in the case of trifunctional siloxanes (T units), the number of silicon atoms forming siloxane bonds can be determined by studying the ratios of (T0) to (T3) as shown below. The detection magnetic field generally has the high magnetic field side in the order of T3 > T2 > T1 > T0. Therefore, the T0 component consists of silicon atoms from the silane coupling agent, and the rest are silicon atoms from the siloxane. Thus, the ratio of monomer (silane coupling agent) component to organopolysiloxane component can be determined from the ratio of the integral values ​​of each peak.

[0068] [Chemistry 2]

[0069]

[0070] (In the formula, R represents an organic group, and X represents a hydrogen atom or an organic group.)

[0071] (i) The organopolysiloxanes of the composition can be manufactured by hydrolytic condensation of the monomer components of each structural unit under an acid or base catalyst. In addition, if necessary, a deprotection reaction of the protected hydroxyl groups can be carried out, thereby enabling the manufacture of organopolysiloxanes having alkyl, aryl, aralkyl, etc., substituted with hydroxyl groups.

[0072] Monomers that can be listed as Q units include tetramethoxysilane, tetraethoxysilane, tetra(n-propoxy)silane, tetra(isopropoxy)silane, tetra(n-butoxy)silane, alkali metal silicates, and active silicic acid obtained by cation exchange of alkali metal silicates.

[0073] Monomers of the T unit include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Ethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-propyltriethoxysilane, etc.

[0074] Among these, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-acryloxypropyltrimethoxysilane can be converted into hydroxyl-substituted products through transesterification with water. γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be converted into diols by reacting the epoxy ring with water. In this way, the siloxanes exhibit good solubility in water and affinity for wood and inorganic filler components, and are therefore preferred.

[0075] Monomers of the D unit include dimethyldimethoxysilane, dimethyldiethoxysilane, methylethyldimethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, diisopropyldimethoxysilane, phenylmethyldimethoxysilane, vinylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc.

[0076] Among these, considering the water solubility and affinity of the obtained siloxanes to wood and flame retardant components, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, etc., can be converted into hydroxyl-substituted products through transesterification with water. γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, etc., can be converted into diols by reacting the epoxy ring with water. Thus, the water solubility and affinity of the siloxanes to wood and inorganic filler components become good, and therefore they are preferred.

[0077] Examples of monomers that can be identified as M-units include trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, n-propyldimethylmethoxysilane, n-propyldiethylmethoxysilane, isopropyldimethylmethoxysilane, isopropyldiethylmethoxysilane, propyldimethylethoxysilane, n-butyldimethylmethoxysilane, n-butyldimethylethoxysilane, n-hexyldimethylmethoxysilane, n-hexyldimethylethoxysilane, n-pentyldimethylmethoxysilane, and n-hexyldimethylmethoxysilane. Hexyldimethylethoxysilane, decyldimethylmethoxysilane, decyldimethylethoxysilane, trimethylsilanol, triethylsilanol, propyldimethylsilanol, propyldiethylsilanol, isopropyldimethylsilanol, isopropyldiethylsilanol, propyldimethylsilanol, butyldimethylsilanol, hexyldimethylsilanol, pentyldimethylsilanol, decyldimethylsilanol, γ-aminopropyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethylmethoxysilane, etc.

[0078] Among these, considering the water solubility and affinity of the obtained organopolysiloxanes to the substrate and flame retardant components, γ-methacryloyloxypropyl dimethylmethoxysilane, γ-methacryloyloxypropyl dimethylethoxysilane, etc., can be converted into hydroxyl-substituted products through transesterification with water. γ-glycidoxypropyl dimethylmethoxysilane, γ-glycidoxypropyl dimethylethoxysilane, β-(3,4-epoxycyclohexyl)ethyl dimethylmethoxysilane, etc., can be converted into diols by reacting the epoxy ring with water. Thus, the siloxanes exhibit good water solubility and affinity to wood and inorganic filler components, and are therefore preferred.

[0079] The M and D units have more than two Si-C bonds and are easily combustible. Therefore, the content of M and D units in all structural units of the organopolysiloxane of component (i) is less than 50 mol%.

[0080] That is, in the above formula (1), a is a number from 0 to 0.5, preferably a number from 0 to 0.2, and more preferably a number from 0 to 0.1.

[0081] In addition, b is a number from 0 to 0.5, preferably a number from 0 to 0.2, and more preferably a number from 0 to 0.1.

[0082] The T unit has a Si-C bond and is less flammable than the D and M units. Therefore, the total number of T units in the organopolysiloxane of component (i) is more than 20 mol%, which results in good flame retardancy.

[0083] That is, in the above formula (1), c is a number from 0.2 to 1.0, preferably from 0.5 to 1.0, and more preferably from 0.6 to 1.0.

[0084] Q units do not contain Si-C bonds and have low flammability, thus having the effect of reducing flame retardancy by suppressing combustion from Si-C bonds. On the other hand, Q units have many crosslinking points and high reactivity. Therefore, from the viewpoint of compatibility and film-forming properties with flame retardant components, in the organopolysiloxane of component (i), the Q units are in the range of 0 to 50 mol%, that is, d is 0 to 0.5, preferably 0 to 0.4.

[0085] (i) The ratio of each structural unit in the component can be, for example, adopted using 29 The ratio of chemical shift to integral value of Si-NMR signal is confirmed by a known method.

[0086] (i) The content of the component relative to the total solid components in the coating composition is preferably 5 to 50% by mass, more preferably 10 to 30% by mass. When it is 5% by mass or more, the film-forming properties and transparency of the coating film become good. In addition, when it is 50% by mass or less, the flame retardancy of the coating film and the suppression of poor appearance around the knots of the wood substrate become good.

[0087] (i) One ingredient may be used alone, or two or more ingredients may be used together.

[0088] (ii) Inorganic packing

[0089] As the inorganic filler for component (ii), known general inorganic fillers can be used, such as inorganic fillers containing elements of group 13, group 14 (excluding carbon), series 1 transition elements, series 2 transition elements, series 3 transition elements, lanthanides, etc.

[0090] As inorganic fillers containing elements of group 13, examples include oxides derived from aluminum, boron, indium, etc., with aluminum oxide being the preferred choice.

[0091] As inorganic fillers containing elements of group 14 (excluding carbon), examples include oxides and salts derived from silicon, tin, etc., with silicon dioxide being the preferred choice.

[0092] Inorganic fillers containing series 1 transition elements include oxides derived from titanium, manganese, zinc, etc., which can also be used as light-absorbing materials for specific wavelengths.

[0093] As inorganic fillers containing series 2 transition elements, examples include oxides derived from yttrium, zirconium, etc., which can also be used as light-absorbing and fluorescent materials for specific wavelengths.

[0094] Examples of inorganic fillers containing series 3 transition elements include oxides derived from hafnium, tantalum, etc.

[0095] As inorganic fillers containing lanthanide elements, examples include oxides derived from lanthanum, cerium, praseodymium, neodymium, terbium, dysprosium, ytterbium, etc. These oxides can also be used as light absorption and fluorescence materials for specific wavelengths.

[0096] In addition, it is possible to use two or more of these products that are formed by chemical bonding.

[0097] There are no particular restrictions on the shape of inorganic fillers; various shapes of inorganic fillers, such as spherical, hollow spherical, porous, sheet-like, needle-like, and fibrous, can be used.

[0098] In particular, as the inorganic filler used in this invention, inorganic oxides and silicates containing elements such as silicon, boron, and aluminum that are ceramized by combustion are preferred. In particular, silicon dioxide, alumina, and layered silicates are examples. In particular, it is preferred to use a filler containing silicon dioxide or the like with layered silicates such as clay because the flame retardancy and the suppression of poor appearance around the joints are better.

[0099] In particular, as the inorganic filler used in this invention, silica particles with an average particle size of 15 to 100 nm calculated based on BET specific surface area are preferred, and silica particles with a particle size of 20 to 80 nm are more preferred. If the average particle size is 15 nm or more, the film-forming properties of the coating are excellent, and if it is 100 nm or less, the transparency of the coating is excellent.

[0100] (ii) The mixing amount of component (ii) is 100 to 900 parts by mass relative to 100 parts by mass of the organopolysiloxane in component (i) above, more preferably 200 to 800 parts by mass. If it is 100 parts by mass or more, the flame retardancy of the coating film becomes good. Furthermore, for example, when the coating composition of the present invention is used as a base coat on a wood substrate and then a top coat is formed thereon, the inorganic filler fills the wood grain on the surface of the wood substrate by forming the base coat film, thereby suppressing the absorption of the top coat coating and suppressing the appearance defects around the knots. In addition, when it is 900 parts by mass or less, the film-forming properties of the coating film become good, and the transparency of the coated article and the suppression effect on the appearance defects around the knots become good. In addition, component (ii) can be used alone or in combination of two or more.

[0101] (iii) Flame retardants

[0102] The coating composition of the present invention may contain one or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based and halogen-based compounds as component (iii).

[0103] Phosphorus compounds include, for example, organophosphorus compounds, phosphoric acid, phosphate esters, phosphates, etc. Specific examples include diammonium hydrogen phosphate, ammonium dihydrogen phosphate, diguanidine phosphate, ammonium polyphosphate, hydrophobic ammonium polyphosphate, guanidine urea phosphate, polycarbamate polyphosphate, melamine phosphate, etc.

[0104] Examples of boron compounds include organoboron compounds, boric acid, borax, boron oxide, borate esters, and borates.

[0105] Magnesium compounds include, for example, magnesium hydroxide and magnesium oxide.

[0106] Examples of aluminum-based compounds include aluminum hydroxide.

[0107] Examples of nitrogen-based compounds include ammonium sulfate, ammonium carbonate, ammonium bicarbonate, and melamine cyanurate.

[0108] Examples of antimony compounds include antimony trioxide.

[0109] Examples of halogenated compounds include zinc chloride.

[0110] Among these, phosphorus-based and boron-based compounds are preferred as flame retardants for the coating compositions of the present invention because they provide good transparency, flame retardancy, and suppression of poor appearance around wood knots in the coated articles.

[0111] As a specific example, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium polyphosphate, boric acid, borax, boron oxide, etc. can be preferred.

[0112] From the viewpoints of flame retardancy, film-forming properties, transparency, and moisture resistance of the coating, the mixing amount of component (iii) is preferably 10 to 300 parts by weight, more preferably 50 to 200 parts by weight, relative to 100 parts by weight of the organopolysiloxane of component (i).

[0113] (iii) One ingredient may be used alone, or two or more ingredients may be used together.

[0114] In the coating composition of the present invention, the ratio of the total mass of component (ii) and component (iii) to the mass of component (i) [(ii) + (iii)] / (i) is preferably 1.0 to 10.0, more preferably 2.0 to 9.0, and even more preferably 3.0 to 8.0. When the ratio is 1.0 or higher, the flame retardancy becomes good, and when it is 10.0 or lower, the moisture resistance, film-forming properties, and transparency of the coating film become good.

[0115] (iv) Solvent

[0116] In addition to the components (i) to (iii) mentioned above, the coating composition of the present invention may also contain a solvent. There are no particular limitations on the solvent, but alcohol and water are preferred; from the viewpoint of environmental protection and ease of acquisition, water is more preferred.

[0117] When using water as a solvent, specific types of fresh water can be used, such as tap water, industrial water, well water, natural water, rainwater, distilled water, and ion-exchanged water, with ion-exchanged water being particularly preferred. Ion-exchanged water can be produced using pure water generators (such as those manufactured by Organo Co., Ltd. under the product name "FW-10" and by Merck Millipore under the product name "Direct-QUV3").

[0118] When using a solvent, the mixing amount relative to the total composition is preferably 20 to 98% by mass, more preferably 70 to 95% by mass. When the solvent content is 20% or more relative to the total composition, the flowability and workability of the coating become good. When the solvent content is 98% or less relative to the total composition, the concentration of the active ingredient in the coating increases, and the thickening of the coating film becomes easier.

[0119] (v) Curing catalyst

[0120] The coating composition of the present invention aims to promote the curing reaction and may contain a curing catalyst. The type, mixing amount, and addition method of the curing catalyst can be determined using known methods and conditions that are consistent with the type of composition.

[0121] In particular, when the coating composition contains an ingredient that cures through a chemical reaction in the presence of a catalyst, it is preferable that the coating composition contains a curing catalyst. Examples of curing catalysts include alkaline compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methoxide, sodium propionate, potassium propionate, sodium acetate, potassium acetate, sodium formate, potassium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, tetramethylammonium acetate, n-hexylamine, tributylamine, diazabicycloundecene (DBU), and dicyandiamide; metal-containing compounds such as tetraisopropyl titanate, tetrabutyl titanate, titanium acetylacetonate, aluminum triisobutoxy, aluminum triisopropoxy, aluminum tri(acetylacetonate), aluminum diisopropoxy (ethyl acetoacetate), aluminum perchlorate, aluminum chloride, cobalt octoate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin octoate, and dibutyltin laurate; and acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid.

[0122] Among these, sodium propionate, sodium acetate, sodium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, tri(acetylacetone)aluminum, diisopropoxy(acetoacetate)aluminum, etc. are particularly preferred, and aluminum-based catalysts, titanium-based catalysts, tin-based catalysts and other metal-containing compounds containing organic ligands are especially preferred.

[0123] The coating composition of the present invention may contain additives that provide additional effects, without impairing the effects of the present invention. Examples of additives include leveling agents. Commonly known leveling agents, such as acrylic, vinyl, silicone, and fluorinated leveling agents, can be used. Among these, silicone leveling agents having a siloxane structure in their main chain are preferred for improving the flame retardancy of the coated article.

[0124] In addition to leveling agents, other additives include UV absorbers, termite repellents, antioxidants, dyes, and pigments. These additives can be used alone or in combination.

[0125] In the coating composition of the present invention, the content of the above-mentioned components (i) to (iii) relative to the total of all solid components is preferably 70% by mass or more, more preferably 80% by mass or more, and most preferably 90% by mass or more.

[0126] The coating composition of the present invention can be manufactured by mixing the above-mentioned components (i) and (ii), as well as components (iii), (iv), (v) and other components as needed. The mixing method for each component can be suitably selected from known methods, and there are no particular limitations. As for the mixing apparatus, for example, a mixer, an oscillating device, an ultrasonic homogenizer, a high-pressure homogenizer, a bead mill, a ball mill, etc., can be used.

[0127] Furthermore, in order to promote the dissolution and dispersion of the components, heating can be performed to carry out the mixing operation within a range that does not impair the effect of the present invention.

[0128] [2] Cured products and coated items

[0129] By curing the coating composition of the present invention, a cured product (cured film) can be obtained. For example, by applying the coating composition of the present invention directly or through one or more other layers to at least a portion of the surface of a wood substrate that is to be flame-retarded, and curing it to form a coating film (coating layer), a flame-retardant coated article can be obtained.

[0130] Furthermore, after the coating composition of the present invention is applied to the surface of a wood substrate, the coating film can be formed by drying without the curing caused by the cross-linking of the organopolysiloxane of component (i) mentioned above.

[0131] Furthermore, the coating composition of the present invention can be preferably used as a base coat coating composition for wood substrates. By applying, drying and curing the coating composition of the present invention on the surface of the wood substrate as needed, a top coat coating composition containing a flame retardant is applied, dried and cured as needed through the base coat composed of the resulting coating film, thereby forming a top coat composed of the resulting coating film, thereby obtaining a flame-retardant coated article.

[0132] At this time, the coating having the above-mentioned base coating and top coating can be formed on a part of the substrate surface or on all of the surface. For example, in a plate-shaped substrate, the coating can be formed on at least one of its surfaces.

[0133] (1) Wood substrate

[0134] Examples of wood-based materials include wood products, logs, plywood, laminated veneer lumber (LVL), engineered wood, cross-laminated timber (CLT), high-strength engineered wood (LSL), laminated veneer board (LVB), laminated veneer sandwich (LVS), parallel veneer laminated timber (PSL), medium-density fiberboard (MDF), structural boards (oriented strand board (OSB)), particleboard, fiberboard, and other wood-based materials.

[0135] In particular, preferred building components include processed timber, engineered timber, and CLT-type substrates.

[0136] In addition, these wood-based materials and products with surface treatments on wood-based materials can also be used, specifically, wood-based materials that have undergone chemical formation treatment, corona discharge treatment, plasma treatment, or treatment with acid or alkali solutions.

[0137] Alternatively, the coating composition of the present invention can be used to coat the surface of a wood substrate on which other functional layers have been pre-formed.

[0138] Other functional layers include rust-proof layers, gas barrier layers, waterproof layers, infrared shielding layers, etc., and any one or more of these can be pre-formed on the wood substrate.

[0139] (2) Primer coating

[0140] The base coat can be formed by applying the coating composition of the present invention described above to at least a portion of the surface of a wood substrate, drying it, and curing it as needed.

[0141] The conditions for applying and drying the coating composition of the present invention on a wood substrate can be appropriately set according to the type, shape, etc. of the wood substrate to be applied. Specific conditions can be appropriately selected from known conditions.

[0142] As for the coating composition, a suitable method can be selected from known methods, such as brush coating, spraying, dipping, flow coating, roller coating, curtain coating, spin coating, doctor blade coating, etc.

[0143] The coating composition of the present invention is a composition that can form a film at, for example, around 0 to 40°C, preferably around 5 to 35°C, and more preferably can form a film after 24 hours at 25°C.

[0144] Furthermore, in order to shorten the curing time, heating can be carried out within a temperature range that will not adversely affect the substrate.

[0145] (3) Topcoat

[0146] By applying a topcoat coating composition to the aforementioned base coat, drying, and curing as needed, a topcoat can be formed. From the perspectives of moisture resistance, flame retardancy, and film transparency, it is preferable to form a topcoat using, for example, a topcoat coating composition containing components (A) to (C) below.

[0147] (A) Organopolysiloxanes composed of the unit ratio shown in the following formula (2)

[0148] (B) Flame retardant

[0149] (C) Inorganic packing

[0150] (A) Organopolysiloxane

[0151] (A) The composition is an organopolysiloxane composed of units in the ratio shown in formula (2) below. It should be noted that, unless otherwise specified, in formula (2) below, (R) 5 3SiO 1 / 2 The element represented by (R) is called the M-element, which is composed of (R) 6 The unit cell represented by 2SiO is called a D unit cell, which is composed of (R 7 SiO 3 / 2 The unit represented by () is called the T unit, and the unit represented by (SiO2) is called the Q unit.

[0152]

[0153] In equation (2), R 5 R 6 and R 7 Each of these R groups independently represents a hydrogen atom, or may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups, and consists of an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 5 R 6 and R 7 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms substituted with an amino group, an aryl group having 6 to 20 carbon atoms substituted with an amino group, or an aralkyl group having 7 to 20 carbon atoms substituted with an amino group.

[0154] The alkyl group having 1 to 20 carbon atoms can be straight-chain, branched, or cyclic. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, cyclopentyl, and cyclohexyl. From the perspective of improving the flame retardancy of the coating composition, methyl or ethyl is preferred.

[0155] Examples of aryl groups with 6 to 20 carbon atoms include phenyl and naphthyl groups.

[0156] Aryl groups with 7 to 20 carbon atoms include benzyl and phenethyl.

[0157] Examples of heterocyclic groups include piperidinyl, pyridinyl, pyrroleyl, and thiopheneyl.

[0158] As mentioned above, in equation (2), R 5 R 6 and R 7At least a portion thereof is an alkyl group with 1 to 20 carbon atoms substituted with an amino group, an aryl group with 6 to 20 carbon atoms substituted with an amino group, or an aralkyl group with 7 to 20 carbon atoms substituted with an amino group. γ-aminopropyl and N-(2-aminoethyl)-3-aminopropyl are preferred as such amino-substituted groups.

[0159] If we consider the water solubility of component (A), its affinity with flame retardant components and substrate, etc., R 5 R 6 and R 7 In this formula (2), the total number of alkyl groups with 1 to 20 carbon atoms substituted with amino groups, aryl groups with 6 to 20 carbon atoms substituted with amino groups, or aralkyl groups with 7 to 20 carbon atoms substituted with amino groups is preferably 50 mol% or more, more preferably 55 mol% or more, and even more preferably 60 mol% or more, relative to the total number of silicon atoms in the formula (2).

[0160] Furthermore, R 5 R 6 and R 7 In this context, as a substituent other than the amino-substituted group, methyl or ethyl groups with a low number of carbon atoms in a flammable alkyl chain are preferred, with methyl being more preferred.

[0161] In equation (2), R 8 Each can be independently represented as an alkyl group having 1 to 8 hydrogen atoms or carbon atoms.

[0162] Specific examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, etc.

[0163] Of these, from the perspective of the flame retardancy of the coating composition, R 8 Hydrogen atoms are preferred.

[0164] f is 0 to 0.5, g is 0 to 0.5, h is 0.2 to 1.0, i is 0 to 0.5, and is a number that satisfies f + g + h + i = 1.

[0165] j is a number from 0 to 3.0. From the viewpoint of the water solubility of organopolysiloxanes, a number from 0.1 to 2.0 is preferred. If j exceeds 3.0, the film-forming properties and moisture resistance of the coating composition may deteriorate.

[0166] (A) The organopolysiloxane of component (A) is condensed to some extent, so network formation becomes easier and it is easy to immobilize on the substrate. In addition, the alkoxy group, which is the source of flammable gas, is less than that of monomers (such as silane coupling agents) that do not contain siloxane bonds (Si-O-Si bonds), thus having the advantage of less reduction in flame retardancy.

[0167] The monomer component without siloxane bonds mentioned above is preferably 50% or less by mass, more preferably 30% or less by mass, even more preferably 10% or less by mass, and even more preferably 1% or less by mass relative to the organopolysiloxane of component (A).

[0168] The ratio of the monomer component without siloxane bonds to the organopolysiloxane component can be determined by... 29 The signal and integral ratio in the Si-NMR (nuclear magnetic resonance) spectrum are obtained.

[0169] (A) The organopolysiloxane of component A can be manufactured by hydrolysis and condensation of the monomer components of each structural unit under acid or base catalyst.

[0170] Monomers that can be listed as Q units include tetramethoxysilane, tetraethoxysilane, tetra(n-propoxy)silane, tetra(isopropoxy)silane, tetra(n-butoxy)silane, alkali metal silicates, and active silicic acid obtained by cation exchange of alkali metal silicates.

[0171] Monomers of the T unit include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Ethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-propyltriethoxysilane, etc.

[0172] Among these, considering the solubility of the obtained siloxane in water and its affinity for wood and flame retardant components, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-propyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are preferred, and γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane are even more preferred.

[0173] Monomers of the D unit include dimethyldimethoxysilane, dimethyldiethoxysilane, methylethyldimethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, diisopropyldimethoxysilane, phenylmethyldimethoxysilane, vinylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc.

[0174] Among these, considering the solubility of the obtained siloxane in water and its affinity for wood and flame retardant components, γ-aminopropylmethyldiethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane are preferred.

[0175] Examples of monomers for the M unit include trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, n-propyldimethylmethoxysilane, n-propyldiethylmethoxysilane, isopropyldimethylmethoxysilane, isopropyldiethylmethoxysilane, isopropyldimethylethoxysilane, n-butyldimethylmethoxysilane, n-butyldimethylethoxysilane, n-hexyldimethylmethoxysilane, n-hexyldimethylethoxysilane, n-pentyldimethylmethoxysilane, n-pentyldimethylethoxysilane, and n-hexyldimethyl... Methoxysilane, n-hexyldimethylethoxysilane, n-decyldimethylmethoxysilane, n-decyldimethylethoxysilane, trimethylsilanol, triethylsilanol, n-propyldimethylsilanol, n-propyldiethylsilanol, isopropyldimethylsilanol, isopropyldiethylsilanol, n-butyldimethylsilanol, n-hexyldimethylsilanol, n-pentyldimethylsilanol, n-decyldimethylsilanol, γ-aminopropyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethylmethoxysilane, etc.

[0176] Among these, considering the solubility of the obtained organopolysiloxane in water and its affinity with the substrate and flame retardant components, γ-aminopropyldimethylmethoxysilane and N-(2-aminoethyl)-3-aminopropyldimethylmethoxysilane are preferred.

[0177] Since M and D units have more than two Si-C bonds, they are easily combustible. Therefore, in the organopolysiloxane of component (A), the content of M and D units is preferably less than 50 mol%.

[0178] That is, in the above formula (2), f is preferably a number from 0 to 0.5, more preferably a number from 0 to 0.2, and even more preferably a number from 0 to 0.1.

[0179] In addition, g is preferably a number from 0 to 0.5, more preferably a number from 0 to 0.2, and even more preferably a number from 0 to 0.1.

[0180] The T unit has a Si-C bond and is less flammable than the D and M units. Therefore, the organopolysiloxane of component (A) has good flame retardancy by including more than 20 mol% of T units in all its structural units.

[0181] That is, in the above formula (2), h is preferably a number of 0.2 to 1.0, more preferably a number of 0.5 to 1.0, and even more preferably a number of 0.6 to 1.0.

[0182] Q-units do not contain Si-C bonds and have low flammability, thus reducing flame retardancy by suppressing combustion from Si-C bonds. On the other hand, Q-units have many crosslinking points and high reactivity. Therefore, from the viewpoint of compatibility and film-forming properties with flame retardant components, Q-units are preferably in the range of 0 to 50 mol% of all structural units in the organopolysiloxane of component (A), i.e., preferably 0 to 0.5, more preferably 0.1 to 0.4, and even more preferably 0.3 to 0.4.

[0183] (A) The ratio of each structural unit in the component can be, for example, adopted using... 29 The ratio of chemical shift to integral value of Si-NMR signal is confirmed by a known method.

[0184] (A) The content of component (A) relative to the total amount of the coating composition for the topcoat is preferably 5 to 60% by mass, more preferably 10 to 40% by mass. When it is 5% by mass or more, the film-forming properties, transparency, and moisture resistance of the coating film are improved. In addition, when it is 60% by mass or less, the flame retardancy of the coating film is improved.

[0185] (A) Components may be used alone or in combination of two or more.

[0186] (B) Flame retardant

[0187] (B) The component is one or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based and halogen-based compounds.

[0188] Phosphorus compounds include, for example, organophosphorus compounds, phosphoric acid, phosphate esters, phosphates, etc. Specific examples include diammonium hydrogen phosphate, ammonium dihydrogen phosphate, diguanidine phosphate, ammonium polyphosphate, hydrophobic ammonium polyphosphate, guanidine urea phosphate, polycarbamate polyphosphate, melamine phosphate, etc.

[0189] Examples of boron compounds include organoboron compounds, boric acid, borax, boron oxide, borate esters, and borates.

[0190] Magnesium compounds include, for example, magnesium hydroxide and magnesium oxide.

[0191] Examples of aluminum-based compounds include aluminum hydroxide.

[0192] Examples of nitrogen-based compounds include ammonium sulfate, ammonium carbonate, ammonium bicarbonate, and melamine cyanurate.

[0193] Examples of antimony compounds include antimony trioxide.

[0194] Examples of halogenated compounds include zinc chloride.

[0195] Among these, phosphorus-based compounds and boron-based compounds are preferred as flame retardants for coating compositions used in topcoat layers. In particular, phosphates and polyphosphates, which form a char layer in a short time and easily ensure flame-retardant performance, are more preferred.

[0196] In particular, since the flame retardancy and moisture resistance of the coating are further improved without compromising the transparency of the coating, it is preferable to use water-soluble phosphates and / or polyphosphates in combination with non-water-soluble phosphates and / or polyphosphates.

[0197] The amount of component (B) is preferably 50 to 300 parts by weight, and particularly preferably 75 to 250 parts by weight, relative to 100 parts by weight of the organopolysiloxane in component (A). If it is less than 50 parts by weight, the flame retardancy of the coating film may be insufficient; if it is more than 300 parts by weight, the film-forming properties, transparency, and moisture resistance of the coating film may be poor.

[0198] (B) Components may be used alone or in combination of two or more.

[0199] (C) Inorganic packing

[0200] As the inorganic filler for component (C), well-known general inorganic fillers can be used, such as inorganic fillers containing elements of group 13, group 14 (excluding carbon), series 1 transition elements, series 2 transition elements, series 3 transition elements, lanthanides, etc.

[0201] As inorganic fillers containing elements of group 13, examples include oxides derived from aluminum, boron, indium, etc., with aluminum oxide being the preferred choice.

[0202] As inorganic fillers containing elements of group 14 (excluding carbon), examples include oxides and salts derived from silicon, tin, etc., with silicon dioxide being the preferred choice.

[0203] Inorganic fillers containing series 1 transition elements include oxides derived from titanium, manganese, zinc, etc., which can also be used as light-absorbing materials for specific wavelengths.

[0204] As inorganic fillers containing series 2 transition elements, examples include oxides derived from yttrium, zirconium, etc., which can also be used as light-absorbing and fluorescent materials for specific wavelengths.

[0205] Examples of inorganic fillers containing series 3 transition elements include oxides derived from hafnium, tantalum, etc.

[0206] As inorganic fillers containing lanthanide elements, examples include oxides derived from lanthanum, cerium, praseodymium, neodymium, terbium, dysprosium, ytterbium, etc. These oxides can also be used as light absorption and fluorescence materials for specific wavelengths.

[0207] In addition, it is possible to use two or more of them as products formed by chemical bonding.

[0208] There are no particular restrictions on the shape of the inorganic filler; various shapes of inorganic fillers, such as perfectly spherical, hollow spherical, porous, sheet-like, needle-like, and fibrous, can be used. Among these, fibrous inorganic fillers are preferred because they are highly effective in inhibiting cracking of the ceramic layer formed after combustion and exhibit particularly good flame retardancy.

[0209] In particular, as inorganic fillers for coating compositions used in topcoat layers, inorganic oxides and silicates containing elements such as silicon, boron, and aluminum that are ceramized by combustion are preferred. In particular, since the flame retardancy is improved, it is preferable to use fillers containing silicon dioxide, glass fiber, etc., and layered silicates such as clay in combination.

[0210] The amount of component (C) is preferably 25 to 150 parts by weight, and particularly preferably 50 to 150 parts by weight, relative to 100 parts by weight of the organopolysiloxane in component (A) above. If it is less than 25 parts by weight, the flame retardancy of the coating film may be insufficient; if it is more than 150 parts by weight, the film-forming properties and transparency of the coating film may be poor.

[0211] (C) Components may be used alone or in combination of two or more.

[0212] In the coating composition for topcoat, the ratio of the total mass of component (B) and component (C) to the mass of component (A) [(B) + (C)] / (A) is preferably 1.0 to 4.5, more preferably 1.2 to 4.0, and even more preferably 1.5 to 2.5. When the ratio is 1.0 or higher, the flame retardancy becomes good, and when it is 4.5 or lower, the moisture resistance, film-forming properties, and transparency of the coating film become good.

[0213] (D) Leveling agent

[0214] Topcoat coating compositions may contain (D) components derived from leveling agents.

[0215] As leveling agents, commonly known leveling agents such as acrylic, vinyl, silicone, and fluorinated leveling agents can be used. Among these, silicone leveling agents having a siloxane structure in the main chain are preferred from the perspective of improving the flame retardancy of the coating composition.

[0216] When using component (D), its mixing amount is preferably 1 to 10 parts by mass, more preferably 3 to 6 parts by mass, relative to 100 parts by mass of the organopolysiloxane of component (A). If it is within this range, a topcoat with excellent film-forming properties can be obtained while maintaining flame retardancy and transparency.

[0217] (D) Components may be used alone or in combination of two or more.

[0218] (E) Solvent

[0219] In addition to the components mentioned above, the coating composition for topcoat may contain solvents.

[0220] There are no particular limitations on the solvent, but alcohol and water are preferred. From the viewpoint of environmental protection and ease of acquisition, water is preferred.

[0221] When using water as a solvent, specific types of fresh water can be used, such as tap water, industrial water, well water, natural water, rainwater, distilled water, and ion-exchanged water, with ion-exchanged water being particularly preferred. Ion-exchanged water can be produced using pure water generators (such as those manufactured by Organo Co., Ltd. under the product name "FW-10" and by Merck Millipore under the product name "Direct-QUV3").

[0222] When using a solvent, the mixing amount relative to the total composition of the topcoat is preferably 20 to 80% by mass, more preferably 30 to 60% by mass. When the solvent content is 20% or more relative to the total composition, the flowability and workability of the coating become good; when the solvent content is 80% or less relative to the total composition, the concentration of the active ingredient in the coating increases, and the thickening of the coating film becomes easier.

[0223] The coating composition for the topcoat may contain a curing catalyst for the purpose of promoting the curing reaction. The type, mixing amount, and addition method of the curing catalyst can be determined using known methods and conditions that are consistent with the type of composition. Specifically, the curing catalyst exemplified as component (v) above can be used.

[0224] To the extent that it does not impair the effects of the present invention, the coating composition for the topcoat may contain additives that provide additional effects.

[0225] Examples of additives include ultraviolet absorbers, termite repellents, antioxidants, dyes, and pigments. These additives can be used individually or in combination.

[0226] The content of the total of the above-mentioned components (A) to (C) relative to the solid components of the coating composition for the topcoat is preferably 70% by mass or more, more preferably 80% by mass or more, and most preferably 90% by mass or more.

[0227] The coating composition for the topcoat can be manufactured by mixing the above-mentioned components (A) to (C), as well as components (D), (E), and other components as needed. The mixing method for each component can be appropriately selected from known methods, and there are no particular limitations. As for the mixing apparatus, for example, a mixer, an oscillating device, an ultrasonic homogenizer, a high-pressure homogenizer, a bead mill, a ball mill, etc., can be used.

[0228] Furthermore, in order to promote the dissolution and dispersion of the components, heating can be performed to carry out the mixing operation within a range that does not impair the effect of the present invention.

[0229] The conditions for applying and drying the coating composition for the topcoat onto the aforementioned base coat to form the topcoat can be appropriately set according to the type and shape of the wood substrate. Specific conditions can be appropriately selected from known conditions.

[0230] As for the coating method, a suitable selection can be made from known methods, such as brush coating, spraying, dipping, flow coating, roller coating, curtain coating, spin coating, doctor blade coating, and other coating methods.

[0231] The coating composition for the topcoat is a composition that can form a film at around 0 to 40°C, preferably around 5 to 35°C, and more preferably can form a film after 24 hours at 25°C.

[0232] Furthermore, in order to shorten the curing time, heating can be carried out within a temperature range that will not adversely affect the substrate.

[0233] There are no particular limitations on the coverage of the primer and topcoat, but it is preferred that the primer coverage relative to the substrate be 0.01 to 0.50 kg / m². 2 The coating is preferably applied in a manner that results in a concentration of 0.01–0.10 kg / m³. 2 The method is covered. If it is within this range, the flame retardancy becomes good, and the poor appearance around the joint is suppressed more effectively.

[0234] The preferred topcoat thickness relative to the substrate is 0.1–2.0 kg / m². 2 The coating is applied in a manner that is more preferably 0.2–1.0 kg / m³. 2 The coating is applied in a manner that, if within this range, results in good flame retardancy and a good coating appearance. Furthermore, to achieve the coating amount within the aforementioned range, it is sufficient to apply the coating in a manner where the amount of solid components of the coating composition relative to the substrate falls within the aforementioned range.

[0235] Furthermore, the coated article of the present invention can be coated with one or more layers of a hard coating, a rust-preventive layer, a gas barrier layer, a waterproof layer, an infrared shielding layer, an antifouling layer, a photocatalyst layer, an antistatic layer, etc., on the surface on which the above-mentioned surface coating is formed and on the opposite side thereof. Examples of materials constituting these layers include alkyd resins, acrylic resins, polyurethane resins, acrylic silicone resins, fluoropolymers, silicone resins, epoxy resins, vinylidene chloride copolymer resins, and vinyl chloride resins (both water-based and solvent-based are acceptable). These layers can be applied as a coating liquid or laminated as pre-formed films using pressure-sensitive adhesives or the like.

[0236] Example

[0237] The following examples of synthesis, comparative synthesis, embodiments, and comparative examples are provided to illustrate the present invention in more detail, but the present invention is not limited to these embodiments.

[0238] [1] Preparation of coating compositions for primer coating

[0239] [Examples 1-8, Comparative Examples 1-6]

[0240] A primer coating composition was prepared by mixing the following components using the mixing amounts recorded in Tables 1 and 2 below. Furthermore, the term "effective component concentration" in Tables 1 and 2 refers to the amount of solid component in the mixing amounts of components (i), (comparative), (ii-1), (ii-2), (ii-3), and (iii-1), the mixing amount of component (ii-4), and the mixing amount of component (iii-2) in 100 parts by mass of the coating composition. Additionally, the effective component mass ratios in Tables 1 and 2 are values ​​calculated based on the solid component ratio of each component, with component (i) set to 100.

[0241] (i) Ingredients

[0242] (i-1): A 30% by mass aqueous solution of an organopolysiloxane containing hydroxyl groups (where a = 0, b = 0, c = 1.0, d = 0, e = 0.7, R in formula (1) above). 3 = Methyl group, group represented by the following formula (3), R 4 =Amount of hydrogen atoms and hydroxyl groups substituted (relative to all silicon atoms) = 200 mol%

[0243] [Chemistry 3]

[0244]

[0245] (In the formula, the line with a wavy line indicates the joint end.)

[0246] [Comparative Components]

[0247] (i'-2): The following comparative aqueous dispersions of acrylic resins prepared in Synthesis Example 1

[0248] [Comparative Synthesis Example 1]

[0249] In a five-necked flask equipped with a stirrer, reflux condenser, thermometer, dripping device, and nitrogen inlet tube, 200 parts by weight of ion-exchanged water and 6.0 parts by weight of a non-reactive emulsifier (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.: Hitenol NF0825: anionic) were added. After purging the flask with nitrogen, the temperature was raised to 80°C, and then 1.0 part by weight of potassium persulfate was added. Next, a mixture of 190 parts by weight of methyl methacrylate, 250 parts by weight of butyl acrylate, 10 parts by weight of acrylic acid, 220 parts by weight of ion-exchanged water, and 30.0 parts by weight of the above-mentioned non-reactive emulsifier, which had been stirred and mixed in a separate container beforehand, was continuously dripped over 3.5 hours. Then, while continuing stirring, the mixture was aged at 80°C for 2 hours. Next, a mixture of 2.7 parts by mass of ion-exchanged water and 0.3 parts by mass of a 70% by mass aqueous solution of tert-butyl hydroperoxide was added to the reactor. Then, a mixture of 9.7 parts by mass of ion-exchanged water and 0.3 parts by mass of sodium erythritol was added dropwise over 5 minutes. The mixture was then aged at 80°C for 2 hours while continuing stirring. After cooling to room temperature, 4.0 parts by mass of a 25% by mass ammonia solution was added to adjust the pH to 9.0, yielding an aqueous dispersion of acrylic resin i'-2. The acrylic resin content in the dispersion was 49.8% by mass, and the volume average particle size of the emulsion was 144 nm.

[0250] (ii) Ingredients

[0251] ii-1: Snowtex OL (20% by mass silica aqueous dispersion, particle size 45nm, manufactured by Nissan Chemical Co., Ltd.)

[0252] ii-2: Snowtex O40 (40% by mass silica aqueous dispersion, particle size 22nm, manufactured by Nissan Chemical Co., Ltd.)

[0253] ii-3: Alumina Sol 520-A (20% by mass alumina aqueous dispersion, manufactured by Nissan Chemical Co., Ltd.)

[0254] ii-4: BENTONE-EW NA (hectorite clay, manufactured by Elementis Specialties, inc.)

[0255] (iii) Components

[0256] iii-1: Nonnen W2-50 (50% aqueous solution of phosphorus-nitrogen flame retardant, manufactured by Maruzen Oil Chemical Co., Ltd.)

[0257] iii-2: Boric acid (manufactured by Fujifilm and Kohden Chemical Co., Ltd.)

[0258] [Evaluation of Coating Stability]

[0259] The stability of the primer coating composition was visually evaluated using the following criteria. In this case, any sedimentation of the originally solid, water-insoluble flame retardant and filler components over time, if accompanied by vibration, was not considered a deterioration of coating stability as long as the coating remained usable. The results are shown in Tables 1 and 2.

[0260] 〇: The situation where the components remain in a liquid state without gelling or solid precipitation.

[0261] ×: This indicates that gelation or solid precipitation occurred when the components were mixed.

[0262] [2] Preparation of coating compositions for topcoat

[0263] [Synthesis example 1]

[0264] A 30% by mass aqueous solution of an amino-containing organopolysiloxane (A-1, f = 0, g = 0, h = 0.7, i = 0.3, j = 0.7, R in the above formula (2)) 7 =Methyl, N-(2-aminoethyl)-3-aminopropyl, R 8 =Hydrogen atoms, amine substitution amount (relative to total silicon atoms) = 61 mol% 56.0 g, NonnenW2-50 (B-1, 50% by mass aqueous solution of phosphorus-nitrogen flame retardant, manufactured by Maruzen Oil Chemical Industry Co., Ltd.) 16.7 g, TAIENK (B-2, non-water-soluble ammonium polyphosphate powder, manufactured by Pacific Industries Co., Ltd.) 13.6 g, EPH80M-01N (C-1, glass fiber, manufactured by Nippon Electric Glass Co., Ltd.) 12.7 g, BYK3450 (leveling agent, polyether-modified polydimethylsiloxane, manufactured by BYK Chemicals Japan Co., Ltd.) 0.9 g, to prepare an aqueous coating composition. The solid content ratio of each component in the solution is relative to 100 parts by mass of component (A), 131 parts by mass of component (B), and 76 parts by mass of component (C).

[0265] [3] Production and evaluation of coated timber

[0266] For cedar wood (air-dry specific gravity 0.27–0.49) cut to 300 mm × 300 mm × 20 mm and including knots, dried at 115°C for 24 hours, the primer coatings of Examples 1–8 and Comparative Examples 2–6 were applied to achieve a coating weight of approximately 0.01–0.02 kg / m³ for the solids component. 2 Air dry for 2 hours. Then, apply the topcoat obtained in Synthetic Example 1 to achieve a solid content of approximately 0.38 kg / m².2 The samples were aged at 21–25°C and 45–55% RH until they reached a certain quality. Furthermore, for Comparative Example 1, no primer was applied; instead, the topcoat obtained in Synthetic Example 1 was applied so that the solid content of the coating was approximately 0.38 kg / m². 2 It is aged at a temperature of 21-25℃ and a relative humidity of 45-55%RH until it reaches a certain quality.

[0267] The following tests were conducted on the coated cedar wood (coated timber).

[0268] (1) Coating appearance

[0269] The appearance of the coating around the knots of cedar wood was visually evaluated using the following criteria. The results are shown in Table 1.

[0270] 〇: The coating around the knot is transparent, allowing the wood grain to be identified.

[0271] ×: White turbidity is produced in the coating around the node.

[0272] (2) Moisture resistance

[0273] Five cycles of repeated wet-drying were performed on each type of wood, with one cycle being 40℃, 90%RH (24 hours) → 60℃ (24 hours). After cooling at 20℃, 60%RH for 24 hours, the surface condition of the coating was observed and visually evaluated using the following standards. The results are shown in Table 1.

[0274] 〇: No whitening, deliquescence, or discoloration was found.

[0275] ×: Observation of whitening, deliquescence, and discoloration.

[0276] (3) Flame retardancy

[0277] For each type of wood, a radiant heat intensity of 50 kW / m² is applied. 2 The flame retardancy was evaluated using a cone calorimeter test (ISO-5660-1) and the following standard.

[0278] ◎: The heat generated during heating for 10 minutes is 6 (MJ / m³). 2 The following situations

[0279] The heat generated during heating at 0:10 minutes is 8 (MJ / m³). 2 The following situations

[0280] ×: The heat output ratio during 10 minutes of heating is 8 (MJ / m³) 2 The situation where the coating expands and / or comes into contact with the device (igniter).

[0281] [Table 1]

[0282]

[0283] [Table 2]

[0284]

[0285] *: The expanded coating comes into contact with the device.

[0286] As shown in Table 1, it can be seen that in the coated articles of Examples 1 to 8, which have a base coating composed of a coating composition that satisfies the necessary technical features of the present invention and a top coating containing siloxane compounds, flame retardants and inorganic fillers, the coating has a good appearance and moisture resistance, inhibits whitening around the knots, and has low heat generation during combustion, showing flame retardancy that meets the specifications of quasi-non-combustible wood.

[0287] As can be seen from the above, by setting a base layer composed of a coating film of a coating composition that satisfies the necessary technical features of the present invention, it is possible to fill the gaps between wood fibers, suppress the staining of the topcoat coating into the wood, and form a uniform topcoat, thereby suppressing whitening. In addition, a solid ceramic layer can be formed during combustion, and its fire-resistant and heat-insulating effects greatly improve the flame retardancy of the wood.

[0288] On the other hand, as shown in Table 2, in Comparative Example 1, which lacked a primer coating, whitening occurred around the joint. In Comparative Examples 2 and 3, where the amount of inorganic filler added was insufficient, this resulted in poor flame retardancy. Furthermore, in Comparative Example 4, where the amount of inorganic filler added was excessive, the primer coating was not sufficiently formed, resulting in poor flame retardancy and whitening also occurred around the joint.

[0289] Furthermore, in Comparative Examples 5 and 6, which were provided with a base coating without a siloxane structure, the flame retardancy deteriorated and the coating expanded due to the increase in flammable organic components.

Claims

1. A coating composition comprising: (i) an organopolysiloxane composed of units in the ratio shown in formula (1) below: 100 parts by mass, In the formula, R 1 R 2 and R 3 Each group independently represents a hydrogen atom, or may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups, and may have an ether bond; it may be an alkyl group with 1 to 20 carbon atoms, an aryl group with 6 to 20 carbon atoms, or an aralkyl group with 7 to 20 carbon atoms. 1 R 2 and R 3 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, an aryl group having 6 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, or an aralkyl group having 7 to 20 carbon atoms that can be substituted with a hydroxyl group and may have an ether bond, R 4 Each of the following independently represents an alkyl group having 1 to 8 hydrogen or carbon atoms, where a is 0 to 0.5, b is 0 to 0.5, c is 0.2 to 1.0, d is 0 to 0.5, e is 0 to 3.0, and is a number satisfying a + b + c + d = 1. (ii) Inorganic filler: 100-900 parts by weight.

2. The coating composition according to claim 1, wherein, The R 1 R 2 and R 3 The total number of hydroxyl groups contained therein is more than 50 mol% relative to the total number of silicon atoms in the formula (1).

3. The coating composition according to claim 1 or 2, wherein, The inorganic filler (ii) comprises one or more selected from silica, alumina and layered silicates.

4. The coating composition according to any one of claims 1 to 3, wherein, relative to 100 parts by weight of component (i), it further comprises 10 to 300 parts by weight of (iii) one or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based and halogen-based compounds.

5. The coating composition according to claim 4, wherein, The ratio of the total mass of component (ii) and component (iii) to the mass of component (i) [(ii) + (iii)] / (i) is 2.0 to 9.

0.

6. The cured product of the coating composition according to any one of claims 1 to 5.

7. Covered items, among which, The surface of the wood substrate has at least a portion of a coating layer consisting of a coating film made of the coating composition according to any one of claims 1 to 5, either directly or indirectly through one or more other layers.

8. Covered items, among which, At least a portion of the surface of the wood substrate is provided with a base coat consisting of a coating film made of the coating composition according to any one of claims 1 to 5, and a top coat consisting of a coating film made of a top coat coating composition comprising component (A), component (B), and component (C). (A) Organopolysiloxanes composed of unit ratios expressed by the following formula (2): 100 parts by mass In the formula, R 5 R 6 and R 7 Each of the following groups independently represents a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, which may be substituted with one or more amino, hydroxyl, epoxy, anhydride, maleimide, vinyl, allyl, acryloyl, methacryloyl, or heterocyclic groups. 5 R 6 and R 7 At least a portion thereof is an alkyl group having 1 to 20 carbon atoms substituted with an amino group, an aryl group having 6 to 20 carbon atoms substituted with an amino group, or an aralkyl group having 7 to 20 carbon atoms substituted with an amino group, R 8 Each of the following independently represents an alkyl group having 1 to 8 hydrogen or carbon atoms, where f is 0 to 0.5, g is 0 to 0.5, h is 0.2 to 1.0, i is 0 to 0.5, j is 0 to 3.0, and the numbers satisfy f + g + h + i = 1. (B) One or more flame retardants selected from phosphorus-based, boron-based, magnesium-based, aluminum-based, nitrogen-based, antimony-based, and halogen-based compounds: 50–300 parts by weight. (C) Inorganic filler: 25-150 parts by weight.

9. The covered article according to claim 8, wherein, The coverage of the base coating relative to the wood substrate is 0.01–0.50 kg / m². 2 The coating thickness relative to the wood substrate is 0.1–2.0 kg / m². 2 .

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