JP7042665B2 - Aqueous dressing - Google Patents

Description

The present invention relates to a novel water-based coating material.

For the purpose of protecting a base material such as steel material, concrete, wood, and synthetic resin from a fire, various foamable coating materials that foam due to a temperature rise at the time of a fire to form a carbonized heat insulating layer have been proposed. As such a foamable coating material, a synthetic resin mixed with a foaming agent, a carbonizing agent, a flame retardant, or the like is known. Conventionally, such foaming coating materials have been mainly solvent-based, but have been made water-based due to recent environmental problems.

For example, a foamable coating material using a synthetic resin emulsion as a binder and containing a flame retardant, a foaming agent, and a carbonizing agent has been developed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-113002

However, although the above-mentioned Patent Document 1 describes that various synthetic resin emulsions can be used, depending on the type of the synthetic resin emulsion, it is possible to achieve both film properties such as water resistance and durability and foamability. It can be difficult, and there is still room for improvement in order to obtain the desired heat protection performance.

In order to solve such a problem, the present inventors have a coating material containing a specific synthetic resin emulsion, which has excellent foamability while ensuring good film physical characteristics, and provides heat-resistant protection performance of a base material. We found that we could exert it, and reached the completion of the present invention.

That is, the present invention has the following features.
1. 1. The coating is a water-based coating material that forms a carbonized heat insulating layer by increasing the temperature.
It contains a synthetic resin emulsion as a binder and contains
The synthetic resin emulsion contains an emulsified polymer of a monomer group containing a vinyl acetate monomer and an alkoxysilyl group-containing monomer, contains a vinyl acetate monomer in a proportion of 20% by weight or more in the monomer group, and has an average particle size of 300 to 300. 1000 nm,
The binder is an aqueous coating material having a gel fraction of 10 to 90% by weight of the forming film.

The present invention is a coating material in which the coating material forms a carbonized heat insulating layer by increasing the temperature, and the coating material contains a specific synthetic resin emulsion as a binder, so that the coating material has physical properties such as water resistance and durability. In addition to being excellent, it exhibits excellent foaming properties when the temperature rises due to a fire or the like, exhibits heat-resistant protection performance, and can enhance the heat-resistant protection of the base material.

Hereinafter, the present invention will be described in detail based on the embodiments thereof.

The present invention is characterized in that the coating film is an aqueous coating material that forms a carbonized heat insulating layer due to a temperature rise (heating) such as a fire, and contains a specific synthetic resin emulsion as a binder (a). The synthetic resin emulsion of the present invention contains a polymer of a monomer group containing a vinyl acetate monomer as a main component, and in the monomer group, the vinyl acetate monomer is contained in an amount of 20% by weight or more (preferably 30% by weight or more, more preferably 40 to 40% by weight). It is characterized by containing 98% by weight, more preferably 50 to 95% by weight). By using a synthetic resin emulsion containing such a vinyl acetate monomer in a specific weight ratio (hereinafter, also referred to as "vinyl acetate resin emulsion"), the temperature of the coating film rises (preferably, the coating film surface temperature is 200 ° C. or higher). More preferably, it exhibits excellent foamability at 250 ° C. or higher), and can stably form a carbonized heat insulating layer to enhance the heat-resistant protection performance of the base material. In the present invention, "α to β" is synonymous with "α or more and β or less".

Specifically, the vinyl acetate resin-based emulsion copolymerizes a vinyl acetate monomer and, if necessary, another monomer copolymerizable with the vinyl acetate monomer (hereinafter, also referred to as "other monomer component"). Examples of other monomer components include (meth) acrylic acid alkyl ester, aromatic monomer, hydroxyl group-containing monomer, carbonyl group-containing monomer, nitrile group-containing monomer, carboxyl group-containing monomer, and phosphoric acid. Group-containing monomer, sulfonic acid group-containing monomer, amino group-containing monomer, vinyl ester-based monomer, vinyl ether-based monomer, amide group-containing monomer, epoxy group-containing monomer, alkoxysilyl group-containing monomer, halogenated vinylidene-based monomer, and others, ethylene, Examples thereof include propylene, isoprene, butadiene, vinylpyrrolidone, vinyl chloride, vinylketone, vinylamide, chloroprene and the like. These can be used by one kind or two or more kinds. The monomer is a general term for compounds having a polymerizable unsaturated double bond.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl (meth) acrylate. ) Acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate. , Octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate and the like. In the present invention, the acrylic acid alkyl ester and the methacrylic acid alkyl ester are collectively referred to as a (meth) acrylic acid alkyl ester.

Examples of the aromatic monomer include styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorstyrene, vinylanisole, vinylnaphthalene, divinylbenzene and the like.
Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like.

Examples of the carbonyl group-containing monomer include acrolein, diacetone (meth) acrylamide, vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone and the like.
Examples of the nitrile group-containing monomer include acrylonitrile and metaacrylonitrile.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid or a monoalkyl ester thereof, itaconic acid or a monoalkyl ester thereof, fumaric acid or a monoalkyl ester thereof, and the like.

Examples of the phosphate group-containing monomer include a monophosphate ester of hydroxyethyl (meth) acrylate, a monophosphate ester of hydroxypropyl (meth) acrylate, and a monophosphate ester of hydroxybutyl (meth) acrylate.
Examples of the sulfonic acid group-containing monomer include allylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 2-methylpropanesulfonic acid and the like.

Examples of the amino group-containing monomer include N-methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and dimethylaminoethyl vinyl ether.

Examples of the vinyl ester-based monomer include vinyl formate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl capricate, and vinyl versatic acid (vinyl neodecanoate, neonanonic acid). Vinyl), vinyl laurate, vinyl stearate, vinyl octylate, vinyl cyclohexanecarboxylate, vinyl benzoate, vinyl esters of various carboxylic acids and the like can be mentioned.
Examples of the vinyl ether-based monomer include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether and the like.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, maleic acid amide, N-methylol (meth) acrylamide and the like.
Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, diglycidyl (meth) acrylate, and allyl glycidyl ether. ;

Examples of the alkoxysilyl group-containing monomer include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltriethoxycisilane, and 3-. (Meta) Acryloxypropylmethyldiethoxysilane, vinyltrimethoxysisisilane, vinyltriethoxysissilane, vinyltriisopropoxysilane and the like can be mentioned.

Examples of the halogenated vinylidene-based monomer include vinylidene chloride and vinylidene fluoride.

The other monomer components are preferably 80% by weight or less (more preferably 70% by weight or less, still more preferably 2 to 60% by weight, in particular, in the monomer group (total monomer including vinyl acetate monomer and other monomer components). It is preferably contained in an amount of 5 to 50% by weight). In the present invention, at least selected from vinyl ester-based monomers, carbonyl group-containing monomers, and alkoxysilyl group-containing monomers as the above-mentioned other monomer components from the viewpoint of film properties such as water resistance and durability and heat resistance protection. It is preferable to contain one or more kinds of monomers, and further, it is preferable to use two or more kinds of these monomers. Thereby, the effect of the present invention can be further enhanced.

Specifically, the content of the vinyl ester-based monomer is preferably 2 to 55% by weight (more preferably 5 to 45% by weight) in the monomer group. The vinyl ester-based monomer has excellent copolymerizability with the vinyl acetate monomer, imparts film physical characteristics such as water resistance and durability, and has excellent foaming properties, and can enhance heat resistance.
The content of the carbonyl group-containing monomer is preferably 0.01 to 10% by weight (more preferably 0.05 to 3% by weight) in the monomer group. The carbonyl group-containing monomer can enhance film characteristics such as water resistance and durability by reacting with a cross-linking agent.
The content of the alkoxysilyl group-containing monomer is preferably 0.001 to 5% by weight (more preferably 0.01 to 2% by weight) in the monomer group. When the content of the alkoxysilyl group-containing monomer is in the above range, it becomes easy to set the gel fraction of the formed film in the predetermined range, and as a result, the physical properties of the film such as water resistance and durability are improved, and the heat resistance is protected. Can be enhanced.

The vinyl acetate resin emulsion of the present invention can be produced by emulsion polymerization of a group of monomers in which the above polymerizable monomers are appropriately mixed. As the polymerization method, a known method may be adopted, and in addition to ordinary emulsion polymerization, soap-free emulsion polymerization, feed emulsion polymerization, seed emulsion polymerization, redox emulsion polymerization and the like can also be adopted. At the time of polymerization, emulsifiers, initiators, dispersants, polymerization inhibitors, polymerization inhibitors, buffers, chain transfer agents, oxidizing agents, reducing agents and the like can also be used.

The average particle size of the vinyl acetate resin emulsion is 300 nm to 1000 nm (preferably 310 to 850 nm, more preferably 320 to 800 nm). When the average particle size is within such a range, the film has excellent physical properties such as water resistance and durability, and also exhibits excellent foaming property when the temperature rises due to a fire or the like, exhibits heat-resistant protection performance, and exhibits the heat-resistant protection performance of the base material. It can exhibit heat resistance. In particular, when the average particle size is at least the above lower limit, excellent foamability is exhibited, and when it is at least the above upper limit, sufficient physical characteristics of the film can be ensured. The average particle size referred to here is a value measured by a dynamic light scattering method. The solid content of the vinyl acetate resin emulsion is not particularly limited, but is preferably 30 to 80% by weight (more preferably 35 to 75% by weight).

The binder (a) of the present invention contains the vinyl acetate-based resin emulsion, but other synthetic resin emulsions may be mixed and used if necessary. In this case, the content of the vinyl acetate-based resin emulsion is preferably 50% by weight or more (more preferably 70% by weight or more, still more preferably 90% by weight or more) in the total solid content of the synthetic resin emulsion. Within such a range, the effect of the present invention can be fully exerted.

The synthetic resin emulsion that can be mixed with the vinyl acetate resin emulsion is not particularly limited as long as the effect of the present invention is not impaired, and a known synthetic resin emulsion can be used. Examples of the type of resin include acrylic resin, acrylic styrene resin, acrylic silicon resin, epoxy resin, fluororesin, urethane resin, polyester resin, polybutadiene resin, alkyd resin, vinyl chloride resin and the like. Such a resin may have a property of causing a crosslinking reaction. These can be used in one type or two or more types.

In the binder (a) of the present invention, the gel content of the forming film is 10 to 90% by weight (preferably 20 to 85% by weight, more preferably 30 to 80% by weight, still more preferably 40 to 80% by weight). It is characterized by being. As a result, it is possible to exhibit excellent foaming properties and exhibit heat resistance protection of the base material while sufficiently ensuring the physical characteristics of the film such as water resistance and durability. The gel fraction is measured by the following method. That is, the binder (a) is applied to the release paper so that the coating thickness is 0.25 mm, and dried at 50 ° C. for 24 hours to form a film. A test piece is obtained by peeling off the formed film and cutting it into a size of 2 × 2 cm. After immersing the test piece in acetone for 24 hours (temperature 25 ° C.), it is calculated by the following formula.
Gel fraction (%) = (weight of coating film after immersion / weight of coating film before immersion) x 100

As the binder (a) of the present invention, it is preferable to use a cross-linking agent capable of reacting with the reactive functional group contained in the synthetic resin emulsion (preferably vinyl acetate resin emulsion). In the present invention, by using such a component, it becomes easy to set the gel fraction of the formed film within the specified range, and as a result, the water resistance, durability, drying property, etc. of the film are further improved, and rainfall, dew condensation, etc. It is possible to suppress the occurrence of swelling / peeling of the coating film due to this and the accompanying deterioration of the heat resistant protection performance.

The cross-linking agent may be selected in combination with the reactive functional group contained in the synthetic resin emulsion. Examples of the combination of these functional groups include an epoxy group-amino group, a hydroxyl group-isocyanate group, a carboxyl group-epoxy group, a carboxyl group-carbodiimide group, a carboxyl group-oxazoline group, a carbonyl group-hydrazide group, and a hydrolyzable silyl group. Each other, etc. can be mentioned. Among these, preferred combinations in the present invention include combinations in which the synthetic resin emulsion used is a carbonyl group-containing synthetic resin emulsion and the cross-linking agent is a compound capable of reacting with a carbonyl group.

Examples of the compound capable of reacting with the carbonyl group include a hydrazide group-containing compound and the like. Specifically, examples of the hydrazide group-containing compound include malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, and maleic acid dihydrazide. These can be used in one type or two or more types.

The mixing ratio of the cross-linking agent is preferably 0.01 to 10 parts by weight (more preferably 0.05 to 5 parts by weight) with respect to 100 parts by weight (solid content) of the synthetic resin emulsion. Within such a range, sufficient foamability can be exhibited, and a sufficient effect of improving physical properties in water resistance, durability, etc. can be obtained.

Further, the aqueous coating material of the present invention may contain, for example, a foaming agent (b), a carbonizing agent (c), a flame retardant (d), a filler (e) and the like.

Examples of the foaming agent (b) include melamine and its derivatives, dicyandiamide and its derivatives, azobistetrasome and its derivatives, azodicarbonamide, urea, thiourea and the like. These can be used alone or in combination of two or more. The content of the foaming agent (b) is preferably 10 to 200 parts by weight (more preferably 20 to 150 parts by weight) with respect to 100 parts by weight of the solid content of the binder (a). The foaming agent (b) of the present invention imparts a foaming action to the coating film due to a temperature rise in the event of a fire or the like, and specifically, when the temperature of the coating film surface is preferably 200 ° C. or higher. It imparts a foaming action.

Examples of the carbonizing agent (c) include pentaerythritol, dipentaerythritol, trimethylolpropane, starch, casein and the like. These can be used alone or in combination of two or more. In the present invention, pentaerythritol and dipentaerythritol are particularly preferable in that they are excellent in dehydration cooling effect and carbonized heat insulating layer forming effect. The content of the carbonizing agent (c) is preferably 10 to 200 parts by weight (more preferably 20 to 150 parts by weight) with respect to 100 parts by weight of the solid content of the binder (a). The carbonizing agent (c) of the present invention imparts an action of forming a carbonized heat insulating layer by dehydrating and carbonizing the binder (a) together with carbonization due to a temperature rise in the event of a fire or the like.

Examples of the flame retardant agent (d) include organic phosphorus compounds such as tricresyl phosphate and diphenyl cresyl phosphate; chlorinated polyphenyl, chlorinated polyethylene, diphenyl chloride, triphenyl chloride, chlorinated paraffin, and fatty acid pentachloride. Chlorine compounds such as esters, perchloropentacyclodecane, chlorinated naphthalene, tetrachloroanophthalic acid; antimony compounds such as antimon trioxide, antimon pentoxide; phosphorus trichloride, phosphorus pentoxide, ammonium phosphate, ammonium polyphosphate, phosphorus Phosphorus compounds such as melamine acid, melamine polyphosphate, melam polyphosphate, melem polyphosphate, boron phosphate, boron polyphosphate, aluminum phosphate, aluminum polyphosphate; and other inorganic compounds such as zinc borate and sodium borate. Be done. These can be used alone or in combination of two or more. In the present invention, the flame retardant (d) preferably contains a phosphorus compound. The content of the flame retardant (d) is preferably 100 to 1000 parts by weight (more preferably 200 to 800 parts by weight) with respect to 100 parts by weight of the solid content of the binder (a).

Examples of the filler (e) include talc, calcium carbonate, sodium carbonate, aluminum oxide (alumina), titanium oxide, zinc oxide, silica, clay, clay, silas, mica, silica sand, silica stone powder, quartz powder, and barium sulfate. And so on. These can be used alone or in combination of two or more. The content of the filler (e) is preferably 3 to 200 parts by weight (more preferably 5 to 150 parts by weight) with respect to 100 parts by weight of the solid content of the binder (a).

Further, in the present invention, the metal hydrate (f) can be contained in addition to the above-mentioned components. The metal hydrate (f) exhibits endothermic properties due to a dehydration reaction or the like when the temperature rises, and is different from the filler (e). Examples of such a metal hydrate (f) include aluminum hydroxide and magnesium hydroxide. These can be used alone or in combination of two or more. The average particle size of the metal hydrate (f) is preferably 0.1 to 20 μm (more preferably 0.2 to 15 μm, still more preferably 0.3 to 8 μm, most preferably 0.4 to 3 μm). Is. The content of the metal hydrate (f) is preferably 1 to 200 parts by weight (more preferably 10 to 100 parts by weight, still more preferably 25 to 25 to parts) with respect to 100 parts by weight of the solid content of the binder (a). 80 parts by weight). The average particle size is measured by a laser diffraction type particle size distribution measuring device.

In addition, the additive may be any additive that does not significantly impair the effects of the present invention, for example, pigments, fibers, wetting agents, plasticizers, film-forming aids, antifreeze agents, lubricants, preservatives, fungicides. , Antifungal agents, antibacterial agents, thickeners, leveling agents, dispersants, antifoaming agents, cross-linking agents, ultraviolet absorbers, antioxidants, light stabilizers, water, solvents and the like.

The water-based coating material of the present invention is suitable as a foamable fireproof coating material applied to the surface coating of structures such as buildings and civil engineering structures. Specifically, it can be applied to various base materials such as walls, pillars, floors, beams, roofs, stairs, ceilings, and doors. Applicable base materials include, for example, concrete, mortar, siding board, extruded board, gypsum board, pearlite board, brick, plastic, wood, metal, steel frame (steel material), glass, porcelain tile and the like. These base materials may be those having a film formed on the surface thereof, those having some kind of base treatment (rust prevention treatment, flame retardant treatment, etc.), those having wallpaper attached, and the like.

When the water-based coating material of the present invention is applied to a base material, for example, a coating tool such as a spray, a roller, a brush, or a trowel may be used to apply the water-based coating material in one or several steps. .. The film thickness to be finally formed may be appropriately set depending on the desired functionality, application site, etc., but is preferably about 0.4 to 5 mm.

In the present invention, in order to protect the coating film formed by the water-based coating material, a topcoat material may be further applied if necessary. Such a topcoat material can be formed by applying a known covering material. As the topcoat material, for example, a coating material such as vinyl acetate resin-based, acrylic resin-based, urethane resin-based, acrylic silicon resin-based, or fluororesin-based can be used. The topcoat material may be applied by a known application method, and for example, a coating tool such as a spray, a roller, or a brush can be used.

Examples are shown below to further clarify the features of the present invention. However, the present invention is not limited to this range.

(Aqueous dressing 1-5)
The synthetic resin emulsion shown in Table 1 is used as a binder, and 70 parts by weight of the foaming agent (b), 70 parts by weight of the carbonizing agent (c), and the flame retardant (d) are used with respect to 100 parts by weight of the synthetic resin emulsion (solid content). ) 300 parts by weight, 70 parts by weight of the filler, and 30 parts by weight of the additive were mixed by a conventional method to obtain 1 to 5 aqueous coating materials. The following raw materials were used.

・ Bonding material (a)
Synthetic resin emulsions (a1) to (a5) were prepared by emulsion polymerization of the monomer components shown in Table 1. The cross-linking agent (azipic acid dihydrazide) was mixed after preparing a synthetic resin emulsion. The particle size of each synthetic resin emulsion and the gel fraction of the formed film are shown in Table 1.

・ Foaming agent (b): Melamine ・ Carbide (c): Dipentaerythritol ・ Flame retardant (d): Ammonium polyphosphate ・ Filler (e): Titanium oxide ・ Additives: Dispersant, antifoaming agent, thickening Agents, film-forming aids, etc.

(Examples 1 to 3, Comparative Examples 1 to 2)
A water-based coating material is applied to a pre-rust-prevented steel sheet with a film applicator at a wet film thickness of 1 mm, cured under standard conditions (temperature 23 ° C, relative humidity 50%) for 7 days, and used as a test piece for the following evaluation. Carried out. The results of each evaluation are shown in Table 2.
<Water resistance evaluation>
After immersing the test piece in water at 23 ° C. for 3 days, the surface condition of the coating film was visually confirmed. The evaluation criteria are as follows.
A: No blister generation was observed B: Blister generation area less than 10% C: Blister generation area 10% or more to less than 20% D: Blister generation area 20% or more

<Heat resistance evaluation 1>
Based on the ISO 5660-1 cone calorimeter method, the foaming ratio and the temperature of the back surface of the steel sheet when 50 kW / m ² of radiant heat is radiated to the surface of the test piece for 15 minutes using an electric heater (CONEIII, manufactured by Toyo Seiki Co., Ltd.). Was measured. Each evaluation standard is as follows.
(Effervescence magnification)
A: Effervescence ratio over 35 times B: Effervescence ratio over 25 times over 35 times C: Effervescence ratio over 20 times over 25 times D: Effervescence ratio 20 times or less (back surface temperature)
A: 300 ° C or higher and lower than 450 ° C B: 450 ° C or higher and lower than 500 ° C C: 500 ° C or higher and lower than 550 ° C D: 550 ° C or higher

Claims (1)

The coating is a water-based coating material that forms a carbonized heat insulating layer by increasing the temperature.
It contains a synthetic resin emulsion as a binder and contains
The synthetic resin emulsion contains an emulsified polymer of a monomer group containing a vinyl acetate monomer and an alkoxysilyl group-containing monomer, contains a vinyl acetate monomer in a proportion of 20% by weight or more in the monomer group, and has an average particle size of 300 to 300. 1000 nm,
The binder is an aqueous coating material having a gel fraction of 10 to 90% by weight of the forming film.