JP7844182B2 - Polyol composition, flame-retardant urethane resin composition, and polyurethane foam - Google Patents

Description

This invention relates to a polyol composition, a flame-retardant urethane resin composition, and a polyurethane foam.

Polyurethane foam, utilizing its excellent thermal insulation properties, is practically used for insulating and preventing condensation in building components such as ceilings, roofs, and walls of apartment buildings, detached houses, and commercial buildings. Polyurethane foam is formed by spraying a flame-retardant urethane resin composition containing polyol compounds and polyisocyanate compounds onto the surface of each structure, followed by foaming and curing.

Although polyurethane foam is lightweight, it is highly flammable because it is an organic material. To improve this, highly flame-retardant polyurethane foam is needed. One method for enhancing the flame retardancy of polyurethane foam is, for example, using a flame retardant such as red phosphorus in a flame-retardant urethane resin composition, as described in Patent Document 1.

Japanese Patent Publication No. 2018-090816

However, conventional flame-retardant urethane resin compositions require the inclusion of a large amount of solid flame retardant to exhibit flame retardancy. As a result, when spraying the composition, problems arise such as the inability to spray over a wide area, reduced adhesion to the sprayed surface, and increased density of the foam.
Therefore, the object of the present invention is to provide a polyol composition that enables the formation of a polyurethane foam that exhibits good flame retardancy even when the content of powders such as solid flame retardants is suppressed.

As a result of diligent research, the inventors have found a solution to the above problem with a polyol composition containing a polyol, a blowing agent, a flame retardant, and a catalyst, wherein the flame retardant comprises a red phosphorus-based flame retardant and one or more phosphate-based flame retardants, and the blowing agent contains HFO, thereby completing the present invention.
The present invention provides the following [1] to [15].

[1] A polyol composition for reacting with a polyisocyanate to obtain a polyurethane foam, wherein the polyol composition contains a polyol, a blowing agent, a flame retardant, and a catalyst, the flame retardant includes a red phosphorus-based flame retardant and a phosphate-based flame retardant, and the blowing agent includes a hydrofluoroolefin.
[2] The polyol composition according to [1], wherein the amount of powder in the polyol composition is 50 parts by mass or less per 100 parts by mass of polyol.
[3] The polyol composition according to [1] or [2], wherein the powder content in the polyol composition is 25% by mass or less relative to the polyol composition.
[4] The polyol composition according to any one of [1] to [3], wherein the ratio of the content of the red phosphorus-based flame retardant to the phosphate-based flame retardant is 1/0.5 to 1/3 by mass ratio (red phosphorus-based flame retardant/phosphate-based flame retardant).
[5] The polyol composition according to any one of [1] to [4], wherein the phosphate-based flame retardant comprises a polyphosphate.
[6] The polyol composition according to [5], comprising the polyphosphate salt ammonium polyphosphate.
[7] The polyol composition according to any one of [1] to [6], wherein the decomposition temperature of the phosphate-based flame retardant is 200°C or higher.
[8] The polyol composition according to any one of [1] to [7], comprising the catalyst a trimerizing catalyst.
[9] The polyol composition according to [8], comprising the trimerizing catalyst, a quaternary ammonium salt.
[10] The polyol composition according to any one of [1] to [9], comprising the catalyst a urethane catalyst.
[11] The polyol composition according to [10], comprising the urethane catalyst, a nitrogen-containing heterocyclic compound.
[12] A polyol composition according to any one of [1] to [11], used for spraying applications.
A flame-retardant urethane resin composition formed from a polyol composition according to any one of [1] to [12] and a polyisocyanate.
[14] The flame-retardant urethane resin composition according to [13], wherein the total heat generated when a polyurethane foam formed from the flame-retardant urethane resin composition is heated for 10 minutes at a radiant heat intensity of 50 kW/ ^{m² in} accordance with the ISO-5660 test method is 8 MJ/ ^m² or less.
A polyurethane foam formed from the flame-retardant urethane resin composition described in [15], [13], or [14].

According to the present invention, it is possible to provide a polyol composition that enables the formation of a polyurethane foam that exhibits good flame retardancy even when the content of powders such as solid flame retardants is suppressed.

This is a schematic diagram showing a sample used for measuring the total heat generation of polyurethane foam.

[Polyol composition]
The polyol composition of the present invention is a polyol composition containing a polyol, a blowing agent, a flame retardant, and a catalyst. Each component will be described in detail below.

<Flame retardant>
The polyol composition of the present invention contains a red phosphorus-based flame retardant and a phosphate-based flame retardant as flame retardants.
Both red phosphorus-based and phosphate-based flame retardants are solid flame retardants, meaning they are solid at room temperature (25°C) and normal pressure (1 atm), and are contained as powders in the polyol composition. In the present invention, by combining a red phosphorus-based flame retardant and a phosphate-based flame retardant, it is possible to form a polyurethane foam that exhibits good flame retardancy even when the powder content in the polyol composition is suppressed.
The following provides a detailed explanation of red phosphorus-based flame retardants and phosphate-based flame retardants.

(Red phosphorus-based flame retardant)
The polyol composition of the present invention contains a red phosphorus-based flame retardant. The red phosphorus-based flame retardant may be red phosphorus alone, red phosphorus coated with a resin, metal hydroxide, metal oxide, etc., or a mixture of red phosphorus with a resin, metal hydroxide, metal oxide, etc. The resin to which the red phosphorus is coated or mixed with red phosphorus is not particularly limited, but examples include thermosetting resins such as phenolic resins, epoxy resins, unsaturated polyester resins, melamine resins, urea resins, aniline resins, and silicone resins. From the viewpoint of flame retardancy, metal hydroxides are preferred as the compound to be coated or mixed. The metal hydroxides described later may be appropriately selected and used.

The content of the red phosphorus-based flame retardant in the polyol composition of the present invention is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 4 to 12 parts by mass, per 100 parts by mass of polyol. When the content of the red phosphorus-based flame retardant is above the lower limit, good flame retardancy can be imparted to the polyurethane foam. Furthermore, when the content of the red phosphorus-based flame retardant is below the upper limit, the content of powder in the polyol composition can be suppressed.
The "powder content in the polyol composition" refers to the total amount of components present as powder in the polyol composition at room temperature and atmospheric pressure. For example, it can be calculated by summing the content of red phosphorus-based flame retardants, phosphate-based flame retardants, other solid flame retardants described later, and fillers other than solid flame retardants.

(Phosphate-based flame retardant)
Specific examples of phosphate-based flame retardants include monophosphates and polyphosphates. It should be noted that the term "phosphate" here includes not only orthophosphates but also phosphates and hypophosphates. The same applies to polyphosphates.
Examples of monophosphates include ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; sodium salts such as monosodium phosphate, disodium phosphate, trisodium phosphate, monosodium phosphite, disodium phosphite, and sodium hypophosphite; potassium salts such as monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, and potassium hypophosphite; lithium salts such as monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphite, dilithium phosphite, and lithium hypophosphite; barium salts such as barium dihydrogen phosphate, barium hydrogen phosphate, tribarium phosphate, and barium hypophosphite; magnesium salts such as magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, and magnesium hypophosphite; calcium salts such as calcium dihydrogen phosphate, calcium hydrogen phosphate, tricalcium phosphate, and calcium hypophosphite; zinc salts such as zinc phosphate, zinc phosphite, and zinc hypophosphite; and aluminum salts such as monoaluminum phosphate, dialuminum phosphate, trialuminum phosphate, aluminum phosphite, and aluminum hypophosphite. Among these, ammonium salts are preferred, and ammonium dihydrogen phosphate is more preferred.
Examples of polyphosphates include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium polyphosphate amide, and aluminum polyphosphate, with ammonium polyphosphate being preferred among these.
Furthermore, while ammonium polyphosphate comes in various types such as type I and type II depending on its crystal structure, type II ammonium polyphosphate is preferred from the viewpoint of increasing the decomposition temperature and enhancing flame retardancy.
Furthermore, phosphate-based flame retardants may be used individually or in combination of two or more types.

The phosphate-based flame retardant used in this invention preferably has a decomposition temperature of 200°C or higher. Although the effect of a decomposition temperature of 200°C or higher is not certain, it is presumed that the flame retardant effect can be efficiently exerted because it approaches the decomposition temperature of the resin constituting the polyurethane foam. From this viewpoint, the decomposition temperature of the phosphate-based flame retardant is more preferably 210°C or higher, even more preferably 230°C or higher, and even more preferably 260°C or higher. The upper limit of the decomposition temperature is not particularly limited, and is, for example, 400°C.
Furthermore, the decomposition temperature of the red phosphorus-based flame retardant is preferably 300°C or higher, more preferably 350°C or higher, and even more preferably 400°C or higher.
The decomposition temperature can be determined by methods such as TG-DTA measurement.

The content of the phosphate-based flame retardant in the polyol composition of the present invention is preferably 1 to 50 parts by mass, more preferably 4 to 40 parts by mass, and even more preferably 7 to 25 parts by mass, per 100 parts by mass of polyol. When the content of the phosphate-based flame retardant is above the lower limit, good flame retardancy can be imparted to the polyurethane foam. Furthermore, when the content of the phosphate-based flame retardant is below the upper limit, the powder content in the polyol composition can be suppressed.

The polyol composition of the present invention preferably has a mass ratio (red phosphorus-based flame retardant/phosphate-based flame retardant) of 1/0.5 to 1/3, more preferably 1/0.6 to 1/2.8, and even more preferably 1/1 to 1/2.7. When the above content ratio is within this range, it becomes easier to improve flame retardancy while suppressing the powder content in the polyol composition. Furthermore, it becomes easier to achieve appropriate density and color of the polyurethane foam.

(Other solid flame retardants)
The polyol composition of the present invention may contain solid flame retardants other than the red phosphorus-based and phosphate-based flame retardants described above (hereinafter also referred to as "other solid flame retardants"), as long as they do not inhibit the effects of the present invention. Examples of other solid flame retardants include bromine-based flame retardants, boron-based flame retardants, antimony-based flame retardants, chlorine-based flame retardants, metal hydroxides, needle-shaped fillers, and the like. While there are no particular limitations on other solid flame retardants, boron-based flame retardants are preferred among those described above.
Examples of boron-based flame retardants include borax, boron oxide, boric acid, and borates. Examples of boron oxides include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide.
Examples of borates include alkali metals, alkaline earth metals, elements from groups 4, 12, and 13 of the periodic table, and ammonium borates. Specifically, examples include alkali metal borates such as lithium borate, sodium borate, potassium borate, and cesium borate; alkaline earth metal borates such as magnesium borate, calcium borate, and barium borate; zirconium borate, zinc borate, aluminum borate, and ammonium borate.
In the present invention, when a boron-containing flame retardant is used, it is preferably a borate, and more preferably zinc borate.
These other solid flame retardants may be used individually or in combination of two or more types.

When the polyol composition of the present invention contains other solid flame retardants, the content of the other solid flame retardants is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of polyol. Keeping the content of other solid flame retardants in the polyol composition below the above upper limit allows for suppression of the total content of solid flame retardants. From the viewpoint of reducing the powder content in the polyol composition, the less the other solid flame retardant, the better; it should be 0 parts by mass or more per 100 parts by mass of polyol. However, when other solid flame retardants are included, from the viewpoint of allowing them to exert their effect, the content should be, for example, 1 part by mass or more, preferably 5 parts by mass or more.

(Fillers other than solid flame retardants)
Furthermore, the polyol composition may contain fillers other than the solid flame retardants described above. Fillers other than solid flame retardants are solids at room temperature and pressure and exist as powders in the polyol composition. As fillers other than solid flame retardants, alumina, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, ferrites, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dawsonite, hydrotalcite, calcium sulfate, barium sulfate, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, imogolite, sericite, glass beads, silica balloon, aluminum nitride, boron nitride, silicon nitride, graphite, carbon balloon, charcoal powder, various metal powders, magnesium sulfate, lead zirconate titanate, molybdenum sulfide, silicon carbide, various magnetic powders, fly ash, etc. can be used as appropriate. Fillers other than solid flame retardants may be used individually or in combination of two or more types.

The powder content in the polyol composition of the present invention is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of polyol. Furthermore, on a basis of the total amount of polyol composition, it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 17% by mass or less. When the powder content is below the above upper limit, when the flame-retardant urethane resin composition formed from the polyol composition is sprayed, the flame-retardant urethane resin composition can be dispersed over a wide area, the increase in density of the polyurethane foam can be suppressed, and good adhesion can be imparted to the polyurethane foam after spraying.
Furthermore, while there is no particular lower limit to the powder content, from the viewpoint of exhibiting the effects of the present invention through the inclusion of red phosphorus-based flame retardants and phosphate-based flame retardants, it is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 25 parts by mass or more, per 100 parts by mass of polyol. Also, on a basis of the total amount of the polyol composition, it is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more.

(Liquid flame retardant)
In addition to the solid flame retardant described above, a liquid flame retardant may also be used as the flame retardant contained in the polyol composition of the present invention. A liquid flame retardant is one that becomes liquid at room temperature (25°C) and normal pressure (1 atm). While there are no particular limitations on the liquid flame retardant, a phosphate ester-based flame retardant is preferred.

As phosphate ester-based flame retardants, monophosphate esters, condensed phosphate esters, etc., can be used. A monophosphate ester is a phosphate ester containing one phosphorus atom in its molecule. Examples of monophosphate esters include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, and tri(2-ethylhexyl) phosphate; halogen-containing phosphate esters such as tris(β-chloropropyl) phosphate; trialkoxy phosphates such as tributoxyethyl phosphate; aromatic ring-containing phosphate esters such as tricresyl phosphate, trixylenyl phosphate, tris(isopropylphenyl) phosphate, cresyldiphenyl phosphate, and diphenyl(2-ethylhexyl) phosphate; and acidic phosphate esters such as monoisodecyl phosphate and diisodecyl phosphate.

Examples of condensed phosphate esters include aromatic condensed phosphate esters such as trialkyl polyphosphates, resorcinol polyphenyl phosphates, bisphenol A polycresyl phosphates, and bisphenol A polyphenyl phosphates.
Examples of commercially available condensed phosphate esters include "CR-733S,""CR-741," and "CR747" from Daihachi Chemical Industry Co., Ltd., and "ADEKA Stab PFR" and "FP-600" from ADEKA Corporation.

The phosphate ester flame retardants may be used individually from the above-mentioned types, or two or more may be used in combination. Among these, monophosphate esters are preferred from the viewpoint of easily adjusting the viscosity of the polyol composition and improving the flame retardancy of the polyurethane foam, and halogen-containing phosphate esters such as tris(β-chloropropyl) phosphate are more preferred.

The content of the phosphate ester-based flame retardant in the polyol composition is not particularly limited, but is preferably 15 to 90 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 25 to 70 parts by mass, per 100 parts by mass of polyol. When the content of the phosphate ester-based flame retardant is above these lower limits, it becomes easier to impart flame retardancy to the polyurethane foam without excessively increasing the viscosity of the polyol composition or the powder content. Furthermore, when the content of the phosphate ester-based flame retardant is below these upper limits, foaming is not inhibited, making it easier to manufacture the polyurethane foam.

<Polyol>
Examples of polyols used in the present invention include polylactone polyols, polycarbonate polyols, polyester polyols, polymer polyols, and polyether polyols.

Examples of polylactone polyols include polypropiolactone glycol, polycaprolactone glycol, and polyvalerolactone glycol.
Examples of polycarbonate polyols include polyols obtained by the de-alcoholization reaction of hydroxyl group-containing compounds such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, and nonanediol with ethylene carbonate, propylene carbonate, etc.

Examples of polyester polyols include polymers obtained by dehydrating and condensing a polybasic acid and a polyhydric alcohol, and condensates of hydroxycarboxylic acids and the aforementioned polyhydric alcohols.
Examples of polybasic acids include adipic acid, azelaic acid, sebacic acid, isophthalic acid (m-phthalic acid), terephthalic acid (p-phthalic acid), o-phthalic acid (phthalic acid), naphthalenedicarboxylic acid, and succinic acid. Examples of polyhydric alcohols include bisphenol A, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexane glycol, and neopentyl glycol.
Examples of hydroxycarboxylic acids include castor oil and reaction products of castor oil and ethylene glycol.

Examples of polymer polyols include polymers obtained by graft polymerization of ethylenically unsaturated compounds such as acrylonitrile, styrene, methyl acrylate, and methacrylate onto aromatic polyols, alicyclic polyols, aliphatic polyols, and polyester polyols, as well as polybutadiene polyols, or hydrogenated versions thereof.

Examples of polyether polyols include polymers obtained by ring-opening polymerization of at least one alkylene oxide having 2 to 6 carbon atoms, specifically ethylene oxide, propylene oxide, tetrahydrofuran, etc., in the presence of at least one low molecular weight active hydrogen compound having two or more active hydrogen atoms, such as a polyhydric alcohol. Examples of alkylene oxides include at least one of ethylene oxide and propylene oxide.
Examples of low molecular weight active hydrogen compounds having two or more active hydrogen atoms include bisphenol A, ethylene glycol, propylene glycol, butylene glycol, diols such as 1,6-hexanediol, triols such as glycerin and trimethylolpropane, tetrahydric to octahydric alcohols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol, sucrose, glucose, mannose, fructose, methyl glucoside and its derivatives, phloroglucinol, and cresol. Examples include polyols such as pyrogallol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1,3,6,8-tetrahydroxynaphthalene, and 1,4,5,8-tetrahydroxyanthracene; castor oil polyols; (co)polymers of hydroxyalkyl (meth)acrylates; polyfunctional polyols (e.g., 2 to 100 functional groups) such as polyvinyl alcohol; condensates of phenol and formaldehyde (novolac); ethylenediamine; and amines such as butylenediamine.

Polyols used in the present invention are preferably polyester polyols and polyether polyols. Polyols having two hydroxyl groups are also preferred. Among these, aromatic polyester polyols, which are polyester polyols having aromatic rings, are preferred from the viewpoint of improving the flame retardancy of polyurethane foam. In that case, the weighted average aromatic concentration of the polyol is preferably 10% by mass or more, and more preferably 12% by mass or more. The upper limit of the weighted average aromatic concentration of the polyol is not particularly limited, but is, for example, 30% by mass, preferably 25% by mass.
Here, aromatic concentration is obtained by the total mass percentage of carbon and hydrogen atoms constituting the aromatic ring in the polyol, and weighted average aromatic concentration is the aromatic concentration obtained by weighted averaging from the respective carbon and hydrogen atom content of the aromatic ring.
The aromatic polyester polyol is preferably a condensate of an aromatic dicarboxylic acid such as o-phthalic acid (phthalic acid), m-phthalic acid (isophthalic acid), p-phthalic acid (terephthalic acid), or naphthalenedicarboxylic acid with a glycol. In particular, from the viewpoint of improving the flame retardancy of the polyurethane foam, especially its ability to prevent the spread of flame, the aromatic polyester polyol is more preferably a phthalic acid-based polyester polyol, which is a condensate of phthalic acid and glycol, and even more preferably at least one selected from p-phthalic acid-based polyester polyol, which is a condensate of p-phthalic acid and glycol, and o-phthalic acid-based polyester polyol, which is a condensate of o-phthalic acid and glycol.

When the polyol contains an aromatic polyester polyol, the amount is not particularly limited, but it is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 100 parts by mass, per 100 parts by mass of the polyol.

The weighted average hydroxyl value of the polyol is preferably 20 to 370 mgKOH/g, more preferably 50 to 320 mgKOH/g, and even more preferably 100 to 260 mgKOH/g. When the hydroxyl value of the polyol is below the upper limit, the viscosity of the polyol composition tends to decrease, which is preferable from the viewpoint of handling and other factors. On the other hand, when the hydroxyl value of the polyol is above the lower limit, the crosslinking density of the polyurethane foam increases, resulting in higher strength and better workability during spraying.
The hydroxyl value of polyols can be measured according to JIS K 1557-1:2007.

Here, the weighted average hydroxyl value of a polyol is determined by the sum of the products of the hydroxyl values of the individual polyols constituting the polyol and the weight fraction of each individual polyol in the polyol. For example, when using two types of polyols, (d1) and (d2), if the hydroxyl value of polyol (d1) is _X1 and the amount added is _m1 , and the hydroxyl value of polyol (d2) is _X2 and the amount added is _m2 , the weighted average hydroxyl value is expressed by the following formula. Note that the amounts _m1 and _m2 are parts by mass in 100 parts by mass of polyol.
Weighted average hydroxyl value (mgKOH/g) = X ₁ × (m ₁ / (m ₁ + m ₂ )) + X ₂ × (m ₂ / (m ₁ + m ₂ ))

<Catalyst>
The polyol composition of the present invention contains a catalyst. Preferably, the catalyst contains at least one selected from the group consisting of trimerizing catalysts and urethane catalysts, more preferably a trimerizing catalyst, and even more preferably a urethane catalyst in addition to a trimerizing catalyst.

(trimerization catalyst)
A trimerizing catalyst is a catalyst that reacts with the isocyanate groups contained in polyisocyanate to trimerize them and promote the formation of isocyanurate rings. The inclusion of a trimerizing catalyst enhances flame retardancy by generating isocyanurate rings. Furthermore, completing the reaction of the isocyanate groups facilitates the production of polyurethane foams with good foaming properties. Examples of trimerizing catalysts include metal catalysts and ammonium salts.
Examples of metal catalysts used as trimerization catalysts (trimerization metal catalysts) include potassium organic acids, preferably potassium octoates such as potassium 2-ethylhexanoate, potassium acetate, potassium propionate, potassium butanoate, potassium benzoate, and other potassium carboxylates having 2 to 8 carbon atoms.
As the ammonium salt, tertiary ammonium salts such as triethylammonium salt and triphenylammonium salt, and quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium salt, and tetraphenylammonium salt can be used, but among these, quaternary ammonium salts are preferred. The ammonium salt is, for example, an ammonium salt of a carboxylic acid. Examples of carboxylic acids in the ammonium salt include saturated fatty acids having 1 to 10 carbon atoms, preferably 2 to 8 carbon atoms. The hydrocarbon group of the saturated fatty acid may be linear or branched, but branching is preferred. Specific examples of carboxylic acids include 2-ethylhexanoic acid, 2,2-dimethylpropanoic acid, acetic acid, and formic acid, but among these, 2,2-dimethylpropanoic acid is preferred. The trimerization catalyst may be used alone or two or more may be used in combination.
The trimerizing catalyst preferably contains a quaternary ammonium salt. Including a quaternary ammonium salt as the trimerizing catalyst improves stability with respect to hydrofluoroolefins, thereby preventing the decomposition of hydrofluoroolefins and resulting in good foaming properties. Furthermore, it allows the reaction rate to be kept above a certain level, improving the workability when spraying the flame-retardant urethane resin composition.
The trimerization catalyst more preferably contains a quaternary ammonium salt and a trimerized metal catalyst.

The content of quaternary ammonium salt in the polyol composition is preferably 0.1 to 15 parts by mass, more preferably 0.2 to 10 parts by mass, and even more preferably 0.4 to 8 parts by mass, per 100 parts by mass of polyol. By setting the above content of quaternary ammonium salt above the lower limit, stability against HFO and workability during spraying can be improved. Furthermore, by setting the above content of quaternary ammonium salt below the upper limit, the reaction rate can be appropriately controlled.
The content of the trimerized metal catalyst is not particularly limited, but is preferably 0.2 to 13 parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.6 to 8 parts by mass per 100 parts by mass of polyol.
Furthermore, the content of the trimerizing catalyst in the polyol composition is preferably 0.3 to 28 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 16 parts by mass, per 100 parts by mass of polyol.

(Urethane catalyst)
The catalyst used in the polyol composition of the present invention preferably contains a nitrogen-containing heterocyclic compound as a urethane catalyst. The inclusion of a nitrogen-containing heterocyclic compound as a urethane catalyst improves stability with respect to hydrofluoroolefins, thereby preventing decomposition of the hydrofluoroolefins and resulting in good foaming properties. Furthermore, it allows for a reaction rate above a certain level, improving the workability when spraying the flame-retardant urethane resin composition. Among nitrogen-containing heterocyclic compounds, the inclusion of an imidazole derivative is more preferable.
As described above, imidazole derivatives are less affected by hydrofluoroolefins and facilitate the reaction between polyols and polyisocyanates while increasing the stability of the polyol composition. Therefore, by containing imidazole derivatives, the reactivity between the polyol and polyisocyanate is enhanced, resulting in even better foaming properties.
The imidazole derivative is preferably an imidazole in which the 1st and 2nd positions are independently substituted with alkyl groups having 8 or fewer carbon atoms, and the alkyl groups preferably have 6 or fewer carbon atoms, more preferably 4 or fewer carbon atoms. A suitable specific example of an imidazole derivative is represented by the following general formula (1).

(In general formula (1), ^R1 and ^R2 each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.)

In general formula (1), ^R1 and ^R2 each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. The alkyl group and alkenyl group may each be linear or have a branched structure.
Specific examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, isopentyl group, sec-pentyl group, hexyl group, heptyl group, octyl group, and the like.
Specific examples of alkenyl groups include vinyl, 1-propenyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, pentenyl, hexenyl, heptenyl, and octenyl groups.
If the number of carbon atoms in the alkyl or alkenyl groups of ^R1 and ^R2 is greater than or equal to the lower limit, steric hindrance increases, making the reaction less susceptible to the effects of blowing agents such as hydrofluoroolefins, which is preferable. On the other hand, if the number of carbon atoms in the alkyl groups of ^R1 and ^R2 is less than or equal to the upper limit, steric hindrance does not increase excessively, allowing the reaction between the polyol and polyisocyanate to proceed rapidly, and resulting in good foaming properties.
From these viewpoints, ^R1 and ^R2 are each preferably alkyl groups having 1 to 6 carbon atoms, more preferably alkyl groups having 1 to 4 carbon atoms, and even more preferably methyl groups.

Examples of imidazole derivatives represented by general formula (1) include 1,2-dimethylimidazole, 1-ethyl-2-methylimidazole, 1-methyl-2-ethylimidazole, 1,2-diethylimidazole, and 1-isobutyl-2-methylimidazole. Among these, 1,2-dimethylimidazole and 1-isobutyl-2-methylimidazole are preferred from the viewpoint of improving catalyst activity in the presence of hydrofluoroolefins and promoting rapid reaction. Furthermore, 1,2-dimethylimidazole is even more preferred from the viewpoint of further enhancing stability.

The content of the nitrogen-containing heterocyclic compound in the polyol composition is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of polyol. When the content of the nitrogen-containing heterocyclic compound is above the lower limit, urethane bond formation is more likely to occur, the reaction proceeds rapidly, and foaming properties are good. On the other hand, when the content of the nitrogen-containing heterocyclic compound is below the upper limit, the reaction rate is easier to control, which is preferable.

The urethane catalyst preferably contains a metal catalyst in addition to a nitrogen-containing heterocyclic compound. This metal catalyst is generally referred to as a urethane-forming metal catalyst. In this invention, the inclusion of the above-mentioned urethane-forming metal catalyst promotes the reaction between the polyol and polyisocyanate, particularly increasing the initial reaction rate. Furthermore, while including a certain amount or more of the above-mentioned flame retardant inhibits the reactivity of the polyol composition and tends to reduce foaming properties, including the urethane-forming metal catalyst makes it easier to maintain good foaming properties of the polyol composition. From the viewpoint of foaming properties, the above-mentioned metal catalyst preferably contains bismuth or tin, and more preferably contains bismuth. Metal catalysts containing bismuth have low reactivity to HFO and high storage stability. They also tend to improve initial activity without reducing the flame retardancy of the polyurethane foam.

The urethane metal catalyst described above is preferably a metal salt selected from bismuth and tin, and more preferably a bismuth salt. The metal salt is preferably an organic acid metal salt, and more preferably a metal salt of a carboxylic acid having 5 or more carbon atoms. Having 5 or more carbon atoms in the carboxylic acid provides good stability against blowing agents, especially hydrofluoroolefins. Furthermore, from the viewpoint of catalytic activity, the number of carbon atoms in the carboxylic acid is preferably 18 or less, and more preferably 12 or less. The carboxylic acid is preferably an aliphatic carboxylic acid, and more preferably a saturated aliphatic carboxylic acid. The carboxylic acid may be linear or have a branched structure, but it is preferable to have a branched structure.
Specific examples of carboxylic acids include octyl acid, lauryl acid, versatic acid, pentanoic acid, and acetic acid, with octyl acid being preferred among these. In other words, the transition metal salt is preferably a metal salt of octyl acid. These carboxylic acids may be linear as described above, but they may also have a branched structure. An example of octyl acid having a branched structure is 2-ethylhexanoic acid.
Preferred metal salts of carboxylic acids include bismuth salts and tin salts of carboxylic acids, with bismuth salts of octic acid being particularly preferred. Alternatively, the metal salt of the carboxylic acid may be an alkyl metal carboxylic acid salt. For example, the tin salt of the carboxylic acid may be a dialkyltin carboxylic acid salt, and preferably a dioctyltin carboxylic acid salt.
Specific examples of metal salts of carboxylic acids include bismastrioctate, dioctyltin versatate, dibutyltin dilaurate, dioctyltin dilaurate, and tin dioctylate, with bismastrioctate and dioctyltin versatate being preferred, and bismastrioctate being more preferred.

The content of the above-mentioned urethane metal catalyst in the polyol composition is not particularly limited, but is preferably 0.05 to 8 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.3 to 3 parts by mass, per 100 parts by mass of polyol.

<Foaming agent>
The foaming agent contains hydrofluoroolefin (hereinafter also referred to as "HFO"). Using HFO can reduce environmental impact.
Examples of HFOs include fluoroalkenes with approximately 3 to 6 carbon atoms. Furthermore, HFO may also be a hydrochlorofluoroolefin containing a chlorine atom; therefore, it may also be a chlorofluoroalkene with approximately 3 to 6 carbon atoms.
Examples of HFOs include trifluoropropene, tetrafluoropropene such as HFO-1234, pentafluoropropene such as HFO-1225, chlorodifluoropropene, chlorotrifluoropropene such as HFO-1233, and chlorotetrafluoropropene.
More specifically, 3,3,3-trifluoropropene (HFO-1243zf), trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,1,3,3-tetrafluoropropene, trans-1,2,3,3,3-pentafluoropropene (HFO-1225ye(E)), cis-1,2,3,3,3-pentafluoropropene Examples include ruolopropene (HFO-1225ye(Z)), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,1,2,3,3-pentafluoropropene (HFO-1225yc), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)), 1,1,1,4,4,4-hexafluorobuto-2-ene (HFO-1336mzz), and cis-1-chloro-2,3,3,3-tetrafluoropropene (HFO-1224yd(Z)). Among these, HFO-1233zd(E) is preferred.

In the present invention, a blowing agent other than HFO may be used in combination with HFO. Examples of blowing agents other than HFO include organic physicoblasting agents such as water, low-boiling point hydrocarbons, and ether compounds, and inorganic physicoblasting agents such as nitrogen gas, oxygen gas, argon gas, and carbon dioxide gas, with water being preferred. These blowing agents may be used individually or in combination of two or more.
Examples of the low-boiling hydrocarbons mentioned above include propane, butane, pentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, and cycloheptane.
Examples of the ether compounds mentioned above include diisopropyl ether.
Among the above, it is preferable that the foaming agent contains hydrofluoroolefin, and it is even more preferable to use hydrofluoroolefin and water in combination.
The foaming agent content is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, and even more preferably 25 to 45 parts by mass, per 100 parts by mass of polyol.

The content of the hydrofluoroolefin used as a foaming agent is preferably 9 to 55 parts by mass, more preferably 19 to 47 parts by mass, and even more preferably 24 to 43 parts by mass, per 100 parts by mass of polyol, from the viewpoint of achieving good foaming properties and, for example, setting the density of the polyurethane foam within a desired range.

As the foaming agent, for example, ion-exchanged water or distilled water can be used as appropriate. Of these, ion-exchanged water is preferred. The water content is preferably 0.1 to 8 parts by mass, more preferably 0.3 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, per 100 parts by mass of polyol. By keeping the water content within the above range, a good balance between flame retardancy and foaming properties is achieved.

<Foam stabilizer>
The polyol composition of the present invention may contain a foam stabilizer. Suitable foam stabilizers include compounds having polar and non-polar portions within their molecule and exhibiting surfactant properties.
The foam stabilizer is not particularly limited, but examples include surfactants such as polyoxyalkylene foam stabilizers like polyoxyalkylene alkyl ethers and silicone foam stabilizers like organopolysiloxanes. As a silicone foam stabilizer, a graft copolymer of polyoxyalkylene glycol, which is a polymer of ethylene oxide or propylene oxide, and polydimethylsiloxane may also be used. Commercially available products can also be used, specifically foam stabilizers such as SH-193 (manufactured by Toray Dow Corning), S-824-02 (Nippon Unicar), SZ-1704 (Nippon Unicar), F501 (Shin-Etsu Chemical Co., Ltd.), and SF-2937F (manufactured by Dow Toray).
The amount of foam stabilizer is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of polyol.

<Other ingredients>
The polyol composition of the present invention may optionally contain one or more antioxidants selected from phenolic, amine, sulfur-based, etc., heat stabilizers, light stabilizers, metal damage inhibitors, antistatic agents, stabilizers, crosslinking agents, lubricants, softeners, pigments, dyes, etc., to the extent that it does not impair the purpose of the present invention.
There are no particular limitations on the method for producing the polyol composition of the present invention; for example, it can be produced by mixing each component.

[Flame-retardant urethane resin composition]
The flame-retardant urethane resin composition of the present invention comprises the above-mentioned polyol composition and polyisocyanate, and is obtained by mixing these.

<Polyisocyanate>
As the polyisocyanate contained in the flame-retardant urethane resin composition of the present invention, various polyisocyanate compounds such as aromatic, alicyclic, and aliphatic compounds having two or more isocyanate groups can be used. Preferably, liquid diphenylmethane diisocyanate (MDI) is used due to its ease of handling, rapid reaction, excellent physical properties of the resulting polyurethane foam, and low cost. Examples of liquid MDI include crude MDI (also called polymeric MDI). Specific commercially available liquid MDI products include "44V-10" and "44V-20" (manufactured by Sumika Covestro Urethane Co., Ltd.) and "Millionate MR-200" (manufactured by Nippon Polyurethane Industry Co., Ltd.). Alternatively, uretonimine-containing MDI (for example, "Millionate MTL" as a commercially available product: manufactured by Nippon Polyurethane Industry Co., Ltd.) may also be used. Furthermore, a polyisocyanate compound may be used that has been pre-treated to increase its affinity with polyols by reacting some of the isocyanate active groups within the polyisocyanate compound with a hydroxyl group-containing compound. In addition to liquid MDI, other polyisocyanates may be used in combination, and any polyisocyanate known in the field of polyurethanes can be used without limitation.

The isocyanate index of the flame-retardant urethane resin composition of the present invention is preferably 200 or higher, more preferably 230 or higher, even more preferably 250 or higher, and even more preferably 260 or higher, from the viewpoint of properly forming polyurethane foam and imparting good flame retardancy.
Furthermore, the isocyanate index of the flame-retardant urethane resin composition is preferably 450 or less, more preferably 420 or less, even more preferably 400 or less, and even more preferably 350 or less. When the isocyanate index is below these upper limits, flame retardancy that is sufficiently commensurate with the manufacturing cost can be obtained.
The isocyanate index (INDEX) is calculated using the following method.

INDEX = Equivalents of polyisocyanate ÷ (Equivalents of polyol + Equivalents of water) × 100
Here,
Polyisocyanate equivalent = Number of polyisocyanates used × NCO content (%) × 100 / NCO molecular weight. Polyol equivalent = OHV × Number of polyols used ÷ Molecular weight of KOH, where OHV is the hydroxyl value of the polyol (mg KOH/g).
The equivalent amount of water = number of parts of water used × number of OH groups in water / molecular weight of water. In the above formula, the unit of the number of parts used is weight (g), the molecular weight of the NCO group is 42, the NCO content is the proportion of NCO groups in the polyisocyanate compound expressed as mass %, and for the sake of unit conversion in the above formula, the molecular weight of KOH is assumed to be 56100, the molecular weight of water is assumed to be 18, and the number of OH groups in water is assumed to be 2.

<Total heat output>
The polyurethane foam formed from the flame-retardant urethane resin composition of the present invention preferably has a total heat generation of 8 MJ/ ^m² or less when heated for 10 minutes at a radiant heat intensity of 50 kW/ ^m² in accordance with the ISO 5660 test method. By having a total heat generation of 8 MJ/ ^m² or less, the polyurethane foam made from the flame-retardant urethane resin composition of the present invention has a predetermined flame retardancy.
From the viewpoint of further improving the flame retardancy of the foam, the total heat generation is more preferably 7 MJ/ ^m² or less, and even more preferably 6.5 MJ/ ^m² or less.

The total calorific value mentioned above is measured by a cone calorimeter test, and can be measured in detail by the method described in the examples. The polyurethane foam used for the cone calorimeter test is formed from a flame-retardant urethane resin composition by the method described in the examples.

[Polyurethane foam]
The polyurethane foam formed from the flame-retardant urethane resin composition of the present invention is formed from the above-described flame-retardant urethane resin composition, and specifically, is obtained by foaming and curing the flame-retardant urethane resin composition.
The polyurethane foam of the present invention is formed from a polyol composition containing a combination of a red phosphorus-based flame retardant and a phosphate-based flame retardant. Therefore, the foam can exhibit good flame retardancy while keeping the powder content in the polyol composition low.

[Application]
The polyol composition, flame-retardant urethane resin composition, and polyurethane foam formed from the present invention are not particularly limited in their uses, but can be used to fill cavities in structures such as buildings, furniture, automobiles, trains, and ships, or to spray onto such structures. In particular, it is preferable to use them for spraying onto surfaces such as walls, ceilings, roofs, and floors, i.e., for spray applications. Since the polyol composition of the present invention has a reduced powder content, when the composition is used for spray applications, the flame-retardant urethane resin composition formed from the composition can be dispersed over a wide area. Furthermore, after the above-mentioned dispersion, the polyurethane foam formed on the sprayed surface exhibits good adhesion to the sprayed surface, preventing the polyurethane foam from peeling off the sprayed surface.
Spraying can be carried out using a spraying device (e.g., GRACO A-25) and a spray gun (e.g., Gasmar D-gun). Spraying can be performed by adjusting the temperature of the polyol composition and polyisocyanate composition, which are in separate containers, in the spraying device, mixing them by collision at the tip of the spray gun, and atomizing the mixture with air pressure. The spraying device and spray gun are well-known and commercially available products can be used. Furthermore, the raw material temperature settings and pressure can be the same as those for spraying polyurethane foam.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[Materials used]
The components used in each example and comparative example are as follows:

<Polyol>
• Aromatic polyester polyol: p-phthalate-based polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RLK-087, aromatic concentration 8%, hydroxyl value = 200 mg KOH/g)
• Aromatic polyester polyol: p-phthalate-based polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RFK-505, aromatic concentration 22%, hydroxyl value = 250 mg KOH/g)
• Aromatic polyester polyol: o-phthalate-based polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RDK-133, aromatic concentration 23%, hydroxyl value = 315 mg KOH/g)

<Foam stabilizer>
• Silicone-based foam stabilizer (manufactured by Dow-Toray, product name: SH-193)

<Catalyst>
(1) Trimerization catalyst/alkali metal salt: Potassium 2-ethylhexanoate (manufactured by Evonik, product name: DABCO K-15, concentration 70-80% by mass)
• Quaternary ammonium salt: 2,2-tetramethylammonium dimethylpropanoate (Evonik, product name: DABCO TMR7), concentration 45-55% by mass
(2) Urethane catalyst - 1,2-dimethylimidazole (manufactured by Tosoh Corporation, product name: TOYOCAT®-DM70, concentration 65-75% by mass)
・Bismuth 2-ethylhexanoate (urethane metal catalyst: manufactured by Nitto Chemical Co., Ltd., product name: Bi28, concentration 81-90% by mass)

<Liquid Flame Retardant>
• Phosphate ester-based flame retardant: Tris(β-chloropropyl) phosphate (manufactured by Daihachi Chemical Co., Ltd., product name: TMCPP)

<Solid flame retardants>
- Ammonium polyphosphate-1 (manufactured by Clariant Chemicals, product name: EXOLIT AP422, decomposition temperature: 275°C or higher)
- Ammonium polyphosphate 2 (manufactured by Taihei Chemical Industry Co., Ltd., product name: Taien K, decomposition temperature: 240°C or higher)
• Ammonium dihydrogen phosphate (manufactured by Taihei Chemical Industry Co., Ltd., product name: Ammonium phosphate C, decomposition temperature: 200°C or higher)
• Metal hydroxide (aluminum hydroxide) (manufactured by Almorix, product name: B-303)
- Red phosphorus-based flame retardant (manufactured by Phosphorus Chemical Industry Co., Ltd., product name: Nova Excel 140, decomposition temperature: 490°C)
• Zinc borate (manufactured by Hayakawa Shoji Co., Ltd., product name: FirebrakeZB)

<Foaming agent>
• Ion-exchanged water • HFO-1233zd <Hydrofluoroolefin> (Honeywell, product name: Solstice LBA)

<Polyisocyanate>
- MDI (manufactured by Sumika Covestro Urethane Co., Ltd., product name: 44V-20)

The methods for measuring the various physical properties of polyurethane foam and evaluating the properties of polyol compositions are as follows. Unless otherwise specified, the polyurethane foam was prepared at an ambient temperature of 20°C.
[Total heat generation]
As shown in Figure 1, a flame-retardant urethane resin composition was sprayed onto a gypsum board 11 measuring 300 x 300 mm and 12.5 mm thick to obtain a polyurethane foam 10. Then, while leaving the surface portion 10A of the polyurethane foam 10, the portion enclosed by the dashed line was cut out so that the total thickness of the polyurethane foam 10 and the gypsum board 11 was approximately 50 mm, thereby obtaining a cut-out portion 12.
The cut portion 12 obtained as described above was used as a sample for the cone calorimeter test. The total heat generated when the sample was heated for 10 minutes at a radiant heat intensity of 50 kW/ ^m² using a cone calorimeter test in accordance with the ISO 5660 test method was measured. Based on the measured value, the flame retardancy of the polyurethane foam 10 was evaluated. The evaluation criteria for flame retardancy are as follows.
◎: 7MJ/m ² or less〇: 7MJ/m ² over 8MJ/m ² or less ×: 8MJ/m ² or less

[Dispersibility]
A flame-retardant urethane resin composition was sprayed onto a 300 x 300 mm gypsum board from a height of 1 m vertically upwards toward the center of the board. After the composition hardened, the percentage of the area of the composition sprayed onto the gypsum board (hereinafter referred to as the "percentage of sprayed area") was determined. Based on the percentage of sprayed area, the sprayability of the flame-retardant urethane resin composition was evaluated according to the following evaluation criteria.
○: The proportion of the area covered by the spray was 60% or more.
×: The percentage of the sprayed area was less than 60%.

[Adhesiveness]
The adhesion of polyurethane foam, which was peeled off by hand after being sprayed with a flame-retardant urethane resin composition onto gypsum board, was evaluated according to the following criteria.
○: It required very strong force to remove the foam, and it could not be easily removed.
×: The foam could be easily removed without requiring any force.

[Spray density]
The flame-retardant urethane resin composition was sprayed twice in the thickness direction onto a 300 cm x 300 cm slate board to obtain a polyurethane foam with a thickness of approximately 25 mm. The calculation was then performed based on the thickness and weight of the foam.

[Examples 1-15, Comparative Examples 1-3]
Polyol compositions and polyisocyanates prepared according to the formulations described in Table 1 were respectively filled into a spraying apparatus. Subsequently, using a spray gun, the polyol composition and polyisocyanate were impact-mixed in a 20°C atmosphere to obtain a flame-retardant urethane resin composition. This composition was then sprayed in a mist onto gypsum board or slate board as described in the evaluation method above, and foamed to obtain a polyurethane foam.
The spray machine and spray gun used were both commercially available products.

The mass parts of each catalyst represent the mass parts of the product.

As described above, the polyol compositions prepared in each example were able to impart good flame retardancy to polyurethane foams even when the amount of powder was suppressed. Furthermore, when the flame-retardant urethane resin composition formed from the polyol composition was sprayed, it was possible to distribute it over a wide area, impart good adhesion to the polyurethane foam formed after spraying, and suppress the increase in density of the polyurethane foam, thus enabling the production of high-quality polyurethane foams.
In contrast, the polyol composition prepared in Comparative Example 1 had a high powder content, making it impossible to adequately distribute the composition, impart good adhesion to the polyurethane foam, or suppress the increase in density of the polyurethane foam, thus failing to produce a high-quality polyurethane foam. Furthermore, although the polyol compositions prepared in Comparative Examples 2 and 3 had powder content suppressed to the same extent as in each example, they did not contain a phosphate-based flame retardant, and therefore could not impart good flame retardancy to the polyurethane foam.

10 Polyurethane foam 10A Surface part 11 Gypsum board 12 Cut-out part

Claims (8)

A polyol composition for obtaining a polyurethane foam by reacting with a polyisocyanate,
The polyol composition contains a polyol, a blowing agent, a flame retardant, and a catalyst.
The aforementioned flame retardant includes a red phosphorus-based flame retardant and a phosphate-based flame retardant.
The blowing agent comprises a hydrofluoroolefin,
The powder content in the polyol composition is 25% by mass or less based on the total amount of the polyol composition.
The catalyst comprises a trimerizing catalyst and a urethane catalyst.
The trimerizing catalyst comprises a quaternary ammonium salt and a trimerizing metal catalyst, and the urethane catalyst comprises a bismuth salt and an imidazole derivative.
A polyol composition comprising the phosphate-based flame retardant ammonium polyphosphate . The polyol composition according to claim 1, wherein the powder content in the polyol composition is 50 parts by mass or less per 100 parts by mass of polyol. The polyol composition according to claim 1 or 2, wherein the ratio of the content of the red phosphorus-based flame retardant to the phosphate-based flame retardant is 1/0.5 to 1/3 by mass ratio (red phosphorus-based flame retardant/phosphate-based flame retardant). The polyol composition according to any one of claims 1 to 3 , wherein the decomposition temperature of the phosphate-based flame retardant is 200°C or higher. A polyol composition according to any one of claims 1 to 4 , for use in spray applications. A flame-retardant urethane resin composition formed from a polyol composition according to any one of claims 1 to 5 and a polyisocyanate. The flame-retardant urethane resin composition according to claim 6, wherein the total heat generated when a polyurethane foam formed from a flame-retardant urethane resin composition is heated for 10 minutes at a radiant heat intensity of 50 kW/ ^m² in accordance with the ISO 5660 test method is 8 MJ/ ^m² or less. A polyurethane foam formed from the flame-retardant urethane resin composition according to claim 6 or 7 .