JP7579100B2 - Flame-retardant urethane resin composition - Google Patents

Description

The present invention relates to a flame-retardant urethane resin composition.

Taking advantage of its excellent insulating properties, polyurethane foam is used to insulate and prevent condensation in building components such as ceilings, roofs, and walls of buildings such as apartment complexes, detached houses, and commercial buildings. Polyurethane foam is formed by spraying a foamable urethane resin composition containing a polyol compound and a polyisocyanate compound onto the surface of each structure, and then foaming and curing the composition.

Although polyurethane foam is lightweight, it is an organic material and therefore flammable. To improve this, polyurethane foam with high flame retardancy is required. From the viewpoint of improving the flame retardancy of polyurethane foam, a method of forming an isocyanurate ring in polyurethane is known.
For example, Patent Document 1 discloses an invention relating to a polyisocyanurate foam (polyurethane foam) formed by specifying the types and amounts of a polyol component, a polyisocyanate component, a catalyst, a blowing agent, etc., and by setting an isocyanate index within a certain range, and describes that the foam has excellent flame retardancy.

JP 2006-321882 A

However, polyurethane foams with a high degree of nuration, in which many isocyanurate rings are formed in polyurethane, are formed by two-stage foaming, which is an initial foaming and a second foaming that occurs a certain time after the initial foaming. Such polyurethane foams formed by two-stage foaming have problems such as shape distortion and poor adhesion to structures. On the other hand, when the degree of nuration is reduced, the problems of the two-stage foaming do not occur, but the flame retardancy decreases.
Therefore, an object of the present invention is to provide a flame-retardant urethane resin composition which is capable of suppressing the two-stage expansion and forming a polyurethane foam having excellent flame retardancy.

As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by a flame-retardant urethane resin composition comprising a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, and a blowing agent, wherein at least one of the polyol compounds is a bromine-containing polyol, and have completed the present invention. That is, the present invention provides the following items [1] to [11].
[1] A flame-retardant urethane resin composition comprising a polyol compound, a polyisocyanate compound, a liquid flame retardant, a blowing agent, and a catalyst, wherein at least one of the polyol compounds is a bromine-containing polyol.
[2] The flame-retardant urethane resin composition according to [1], wherein the bromine-containing polyol has bisphenol A as a basic skeleton.
[3] The flame-retardant urethane resin composition according to [1] or [2], containing 80 parts by mass or more of an aromatic ring-containing polyol per 100 parts by mass of the polyol compound.
[4] The flame-retardant urethane resin composition according to any one of [1] to [3], having an isocyanate index of 90 to 700.
[5] The flame-retardant urethane resin composition according to any one of [1] to [4], wherein the moisture content of a polyol composition constituting the flame-retardant urethane resin composition is 0.2% or more as measured by a Karl Fischer measurement device.
[6] The flame-retardant urethane resin composition according to any one of [1] to [5], wherein the bromine-containing polyol is contained in an amount of 30 parts by mass or more per 100 parts by mass of the polyol compound.
[7] The flame-retardant urethane resin composition according to any one of [1] to [6], wherein the catalyst is substantially free of a trimerization catalyst.
[8] The flame-retardant urethane resin composition according to any one of [1] to [7], wherein the viscosity of the polyol composition constituting the flame-retardant urethane resin composition at 20°C is 1500 mPa·s or less.
[9] The flame-retardant urethane resin composition according to any one of [1] to [8], which is used for spray applications.
[10] The flame-retardant urethane resin composition according to any one of [1] to [9], which is substantially free of inorganic filler.
[11] A polyurethane foam formed from the flame-retardant urethane resin composition according to any one of [1] to [10].

The present invention provides a flame-retardant urethane resin composition that suppresses two-stage foaming and can form a polyurethane foam with excellent flame retardancy.

[Flame-retardant urethane resin composition]
The flame-retardant urethane resin composition of the present invention comprises a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, and a foaming agent, and at least one of the polyol compounds is a bromine-containing polyol.
The flame-retardant urethane resin composition of the present invention uses a liquid flame retardant in combination with a bromine-containing polyol to improve flame retardancy. When these are used in combination, the flame retardancy of the polyurethane foam can be improved without increasing the degree of nurate conversion, and it is believed that this can also suppress two-stage foaming.

<Liquid flame retardant>
The flame-retardant urethane resin composition of the present invention contains a liquid flame retardant. This improves the flame retardancy of a polyurethane foam formed from the flame-retardant urethane resin composition. Here, the liquid flame retardant is a flame retardant that is liquid at 23° C.
Examples of liquid flame retardants include phosphate flame retardants such as monophosphate and condensed phosphate.
The monophosphate ester is not particularly limited, but includes trimethyl phosphate, triethyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tris(β-chloropropyl) phosphate, and the like.
The condensed phosphate ester is not particularly limited, but examples thereof include resorcinol polyphenyl phosphate (product name: CR-733S), bisphenol A polycresyl phosphate (product name: CR-741), and aromatic condensed phosphate ester (product name: CR747).
The content of the liquid flame retardant is preferably 10 to 120 parts by mass, more preferably 20 to 100 parts by mass, and even more preferably 40 to 90 parts by mass, based on 100 parts by mass of the polyol compound. When the content of the liquid flame retardant is equal to or greater than these lower limits, the flame retardancy of the polyurethane foam is likely to be improved. In addition, the polyol compound containing the bromine-containing polyol can be appropriately diluted. When the content of the liquid flame retardant is equal to or less than these upper limits, foaming is not inhibited, and the polyurethane foam can be easily produced.

<Polyol Compound>
The flame-retardant urethane resin composition of the present invention uses a polyol compound as a raw material for polyurethane foam. The polyol compound includes a bromine-containing polyol. In the present invention, by using the bromine-containing polyol, the flame retardancy of the polyurethane foam formed is improved.

(Bromine-containing polyol)
Examples of the bromine-containing polyol include aromatic bromine-containing polyol and aliphatic bromine-containing polyol. In the present invention, either one of them may be used or both may be used in combination, but the bromine-containing polyol preferably contains an aromatic bromine-containing polyol from the viewpoint of improving flame retardancy. Examples of the aromatic bromine-containing polyol include aromatic bromine-containing polyester polyol and aromatic bromine-containing polyether polyol, and among these, aromatic bromine-containing polyether polyol is preferred from the viewpoint of foaming property.
The bromine-containing polyol is also preferably a polyol having bisphenol A as a basic skeleton, and more preferably a polyol having bromine-containing bisphenol A as a basic skeleton, such as tetrabromobisphenol A. The polyol having bisphenol A as a basic skeleton is more preferably an aromatic bromine-containing polyether polyol.

As the aromatic bromine-containing polyester polyol, for example, one obtained by an esterification reaction between a bromine-containing polycarboxylic acid such as tetrabromophthalic acid and a polyhydric alcohol can be used.
Examples of polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, and bisphenol A. These may be used alone or in appropriate combination of two or more.

As the aromatic bromine-containing polyether polyol, for example, one obtained by addition polymerization of a bromine-containing polyhydric alcohol such as tetrabromobisphenol A with one or more alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide can be used. When using a bromine-containing polyether polyol, it is particularly preferable to use an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton.

Examples of aliphatic bromine-containing polyols include aliphatic bromine-containing polyether polyols and aliphatic bromine-containing polyester polyols, and among these, aliphatic bromine-containing polyether polyols are preferred.

By using a bromine-containing polyol as the polyol compound, a fire spread suppression effect due to the radical trapping effect is exerted, and the flame retardancy and resistance to fire spread of the foam are improved. In order to exert this effect more efficiently, it is preferable to disperse the bromine-containing polyol more uniformly in the flame-retardant urethane resin composition. Therefore, when mixing the bromine-containing polyol with other raw materials, the viscosity may be adjusted by premixing the bromine-containing polyol with a phosphate ester-based flame retardant or the like. By adjusting the viscosity of the bromine-containing polyol, the bromine-containing polyol can be more easily mixed with other raw materials.

From the viewpoint of improving flame retardancy and flame spread resistance, the content of the bromine-containing polyol is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more per 100 parts by mass of the polyol compound. The content of the bromine-containing polyol is not particularly limited in terms of the upper limit, and may be 100 parts by mass or less per 100 parts by mass of the polyol compound, more preferably 90 parts by mass or less, and even more preferably 60 parts by mass or less. By setting the content of the bromine-containing polyol to the above numerical value, other polyol compounds can be blended, making it easier to improve various performances.

The hydroxyl value of the bromine-containing polyol is preferably 100 to 600 mgKOH/g, more preferably 110 to 450 mgKOH/g, and even more preferably 110 to 200 mgKOH/g. The hydroxyl value is a value measured in accordance with JIS K1557-1:2007. In the present invention, by lowering the hydroxyl value of the bromine-containing polyol, it becomes easier to suppress shrinkage and further to improve the strength of the foam.

(Other polyol compounds)
The polyol compound used in the present invention may be the above-mentioned bromine-containing polyol alone, but a polyol other than the bromine-containing polyol (a bromine-free polyol) may also be used.
Examples of the bromine-free polyol include polyether polyols, polyester polyols, etc. Among these, polyester polyols are preferred, and from the viewpoint of flame retardancy, aromatic polyester polyols, i.e., aromatic polyester polyols not containing bromine, are more preferred.
From the viewpoint of flame retardancy, the polyether polyol is preferably a bromine-free aromatic polyether polyol, and it is also preferable to use a bromine-free aromatic polyester polyol and a bromine-free aromatic polyether polyol in combination as the bromine-free polyol.

Examples of the bromine-free polyester polyol include aromatic polyester polyols, which are polyester polyols having an aromatic ring, and aliphatic polyester polyols, with aromatic polyester polyols being preferred as described above.
The bromine-free 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. Among these, from the viewpoint of enhancing the flame retardancy and flame-spreading resistance of the polyurethane foam, the aromatic polyester polyol more preferably contains a phthalic acid-based polyester polyol, which is a condensate of phthalic acid and a glycol, and even more preferably contains a p-phthalic acid-based polyester polyol, which is a condensate of p-phthalic acid and a glycol.
The glycol is not particularly limited, but it is preferable to use low molecular weight aliphatic glycols known as components of polyester polyols, such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol.
The hydroxyl value of the bromine-free aromatic polyester polyol is preferably from 100 to 400 mgKOH/g, and more preferably from 150 to 350 mgKOH/g.

When the polyol compound contains a bromine-free aromatic polyester polyol, its content is not particularly limited, but is preferably 10 to 70 parts by mass, and more preferably 15 to 65 parts by mass, per 100 parts by mass of the polyol compound in the flame-retardant urethane resin composition.

The bromine-free polyether polyol is a polyoxyalkylene polyol obtained by ring-opening addition polymerization of an alkylene oxide to an initiator having two or more active hydrogen atoms, and the initiator does not contain bromine. Specific examples of the initiator include aliphatic polyhydric alcohols (e.g., glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexylene glycol, and cyclohexanedimethanol, triols such as trimethylolpropane and glycerin, tetrafunctional alcohols such as pentaerythritol, and highly functional alcohols such as sucrose and sorbitol), aliphatic amines (e.g., alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, and neopentyldiamine, and alkanolamines such as monoethanolamine and diethanolamine), and aromatic amines (e.g., aniline, tolylenediamine, xylylenediamine, diphenylmethanediamine, and Mannich condensation products).
Among these, the polyether polyol produced by using an initiator having an aromatic ring is the polyether polyol having an aromatic ring, for example, the polyether polyol produced by using an aromatic amine as an initiator is the polyether polyol having an aromatic ring. Among the polyether polyols having an aromatic ring, tolylenediamine-based polyether polyols, Mannich-based polyether polyols, etc. can be preferably used.

The tolylenediamine-based polyether polyol is a tolylenediamine-based polyether polyol produced using tolylenediamine as an initiator.
The Mannich polyether polyol is a polyether polyol obtained by utilizing the Mannich reaction, which is a Mannich condensation product having two or more hydroxyl groups in the molecule, or an alkylene oxide added to such a Mannich condensation product. More specifically, it is a Mannich condensation product obtained by the Mannich reaction of at least one of phenol and its alkyl-substituted derivatives, formaldehyde and alkanolamine, or a polyether polyol obtained by ring-opening addition polymerization of at least one of ethylene oxide and propylene oxide to this compound.

The hydroxyl value of the polyether polyol is preferably 200 to 2000 mg KOH/g, and more preferably 300 to 1000 mg KOH/g. The hydroxyl value is a value measured in accordance with JIS K1557-1:2007.

From the viewpoint of improving the flame retardancy of a polyurethane foam formed from the flame-retardant urethane resin composition of the present invention, the composition preferably contains 80 parts by mass or more, and more preferably 90 parts by mass or more, of an aromatic ring-containing polyol per 100 parts by mass of the polyol compound. The content of the aromatic ring-containing polyol is the total amount of the aromatic ring-containing polyol contained in the bromine-containing polyol and the bromine-free polyol described above.

<Polyisocyanate Compound>
As the polyisocyanate compound contained in the flame-retardant urethane resin composition of the present invention, various polyisocyanate compounds having two or more isocyanate groups, such as aromatic, alicyclic, and aliphatic polyisocyanate compounds, can be used. It is preferable to use liquid diphenylmethane diisocyanate (MDI) because of 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 examples of commercially available liquid MDI include "44V-10" and "44V-20" (manufactured by Sumika Covestro Urethane Co., Ltd.) and "Millionate MR-200" (Nippon Polyurethane Industry Co., Ltd.). In addition, uretonimine-containing MDI (for example, commercially available product "Millionate MTL": manufactured by Nippon Polyurethane Industry Co., Ltd.) may also be used. Also, a part of the isocyanate active group in the isopolycyanate compound may be reacted with a hydroxyl group-containing compound to enhance the affinity with the polyol in advance. In addition to liquid MDI, other polyisocyanate compounds may be used in combination, and the polyisocyanate compounds to be used in combination may be any polyisocyanate compounds known in the technical field of polyurethanes, without any limitations.

The isocyanate index of the flame-retardant urethane resin composition of the present invention is preferably 700 or less, more preferably 500 or less, even more preferably 300 or less, and even more preferably 250 or less. When the isocyanate index is below these upper limits, excess isocyanate is reduced and foaming proceeds smoothly. Therefore, two-stage foaming can be suppressed.
From the viewpoint of properly forming a polyurethane foam, the isocyanate index of the flame-retardant urethane resin composition is preferably 90 or more, more preferably 100 or more, and even more preferably 105 or more.
The isocyanate index (INDEX) is calculated by the following method.

INDEX = equivalents of isocyanate ÷ (equivalents of polyol + equivalents of water) × 100
Where:
Equivalent weight of isocyanate=number of parts of polyisocyanate used×NCO content (%)×100/NCO molecular weight Equivalent weight of polyol=OHV×number of parts of polyol used÷molecular weight of KOH, OHV is the hydroxyl value of polyol (mgKOH/g),
Equivalent number of water = parts of water used x number of OH groups of water / molecular weight of water. In the above formula, the unit 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 in mass%, and for convenience of unit conversion in the above formula, the molecular weight of KOH is 56100, the molecular weight of water is 18, and the number of OH groups of water is 2.

<Catalyst>
The flame-retardant urethane resin composition of the present invention contains a catalyst. Examples of the catalyst include a urethane catalyst and a trimerization catalyst. The trimerization catalyst is a catalyst that promotes trimerization to form an isocyanurate bond. Therefore, from the viewpoint of suppressing two-stage foaming, the flame-retardant urethane resin composition of the present invention preferably does not substantially contain a trimerization catalyst. Here, "substantially does not contain a trimerization catalyst" means that the content of the trimerization catalyst is 3 parts by mass or less relative to 100 parts by mass of the polyol compound. The content of the trimerization catalyst is preferably 2 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0 parts by mass relative to 100 parts by mass of the polyol compound. From such a viewpoint, the catalyst in the present invention is preferably composed of only a urethane catalyst.

The urethane catalyst is a catalyst that accelerates the reaction between a polyol compound and a polyisocyanate compound. Specific examples of the urethane catalyst include amino compounds, tin compounds, bismuth compounds, and metal salts of acetylacetone.
Examples of the amino compound include imidazole compounds such as 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, and imidazole compounds in which the secondary amine functional group in the imidazole ring is substituted with a cyanoethyl group, pentamethyldiethylenetriamine, triethylamine, N-methylmorpholinebis(2-dimethylaminoethyl)ether, bis(2-dimethylaminoethyl)ether, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N'-trimethylaminoethyl-ethanolamine, bis(2-dimethylaminoethyl)ether, N-methyl-N',N'-dimethylaminoethylpiperazine, N,N-dimethylcyclohexylamine, diazabicycloundecene, triethylenediamine, tetramethylethylenediamine, guanidine derivatives, tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, tripropylamine, and the like, and acid-blocked products thereof.
As the amino compound, an imidazole compound is preferable, but it is also preferable to use an imidazole compound in combination with a tertiary amine compound other than the imidazole compound. As the tertiary amine compound, N,N-dimethylcyclohexylamine and the like are preferable.
Examples of the tin compound include stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, etc. Examples of the bismuth compound include bismuth neodecanoate, bismuth octoate, etc.
Examples of acetylacetone metal salts include acetylacetone aluminum, acetylacetone iron, acetylacetone copper, acetylacetone zinc, acetylacetone beryllium, acetylacetone chromium, acetylacetone indium, acetylacetone manganese, acetylacetone molybdenum, acetylacetone titanium, acetylacetone cobalt, acetylacetone vanadium, and acetylacetone zirconium.

Examples of trimerization catalysts include aromatic compounds such as tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, and 2,4,6-tris(dialkylaminoalkyl)hexahydro-S-triazine; alkali metal salts such as potassium acetate, sodium acetate, potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, potassium octylate, and sodium octylate; triazines such as 2,4,6-tris(dialkylaminoalkyl)-hexahydro-S-triazine; aziridines such as 2-ethylaziridine; lead compounds such as lead naphthenate and lead octylate; alcoholate compounds such as sodium methoxide; phenolate compounds such as potassium phenoxide; tertiary ammonium salts such as trimethylammonium salt, triethylammonium salt, and triphenylammonium salt; and quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium, and tetraphenylammonium salt.

The amount of catalyst is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 12 parts by mass, per 100 parts by mass of the polyol compound.

<Foaming Agent>
Specific examples of the blowing agent include water, low-boiling point hydrocarbons, chlorinated aliphatic hydrocarbon compounds, fluorine compounds, hydrochlorofluorocarbon compounds, hydrofluorocarbons, ether compounds, hydrofluoroolefins, etc. Further examples of the blowing agent include organic physical blowing agents such as mixtures of these compounds, and inorganic physical blowing agents such as nitrogen gas, oxygen gas, argon gas, and carbon dioxide gas.
Examples of the low boiling point hydrocarbon include propane, butane, pentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, and cycloheptane.
Examples of the chlorinated aliphatic hydrocarbon compounds include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, and isopentyl chloride.
Examples of the fluorine compound include CHF ₃ , CH ₂ F ₂ , and CH ₃ F.
Examples of the hydrochlorofluorocarbon compounds include trichloromonofluoromethane, trichlorotrifluoroethane, dichloromonofluoroethane (for example, HCFC141b (1,1-dichloro-1-fluoroethane)), HCFC22 (chlorodifluoromethane), and HCFC142b (1-chloro-1,1-difluoroethane).
Examples of the hydrofluorocarbon include HFC-245fa (1,1,1,3,3-pentafluoropropane) and HFC-365mfc (1,1,1,3,3-pentafluorobutane).
The ether compound may, for example, be diisopropyl ether.
Examples of the hydrofluoroolefin include HFO-1233zd(E) (trans-1-chloro-3,3,3-trifluoropropene), HFO-1234yf (2,3,3,3-tetrafluoro-1-propene), HFO-1336mzz(Z) (cis-1,1,1,4,4,4-hexafluorobut-2-ene), and HFO-1224yd(Z).

Among the above, preferred foaming agents are hydrofluoroolefins, water, and the like, and it is preferred to use hydrofluoroolefins and water in combination.
From the viewpoint of adjusting the density of the foam within a desired range, the content of the foaming agent is preferably 5 to 80 parts by mass, more preferably 10 to 65 parts by mass, and even more preferably 25 to 55 parts by mass, relative to 100 parts by mass of the polyol compound.
The amount of the hydrofluoroolefin used as a blowing agent is preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 23 to 50 parts by mass, relative to 100 parts by mass of the polyol compound, from the viewpoint of setting the density of the polyurethane foam in the desired range.
The water used as the blowing agent may be, for example, ion-exchanged water, distilled water, etc. The amount of water relative to 100 parts by mass of the polyol compound is preferably 0.5 to 15 parts by mass, more preferably 1 to 12 parts by mass, and even more preferably 2 to 10 parts by mass.

<Foam stabilizer>
The flame-retardant urethane resin composition of the present invention may contain a foam stabilizer. Examples of foam stabilizers include silicone foam stabilizers such as organopolysiloxanes, but even if there is no silicone component, as long as the structure has a polar part and a non-polar part in the molecule, the surfactant effect can be obtained, so there is no need to be limited to the above types. In addition, the silicone foam stabilizer may also include a graft copolymer of polydimethylsiloxane and polyethylene glycol.
The content of the foam stabilizer is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 8 parts by mass, and even more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the polyol compound. The foam stabilizer may be used alone or in combination of two or more kinds.

The flame-retardant urethane resin composition of the present invention may contain an inorganic filler such as a solid flame retardant, but it is also preferable that the composition is substantially free of inorganic fillers. By substantially not containing inorganic fillers, it is possible to provide a flame-retardant urethane resin composition that is less likely to produce precipitates during storage, has excellent storage stability such as separation, and suppresses wear of equipment used during use.
Here, "substantially free of inorganic filler" means that the content of inorganic filler is 5% by mass or less, and preferably 1% by mass or less, based on the total amount of the flame-retardant urethane resin composition.
The inorganic filler is a component that is not dissolved in a polyol compound or a polyisocyanate at normal temperature and pressure, and is, for example, a component that exists as a powder in a polyol composition described later. Note that the inorganic filler does not include the above-mentioned catalyst.

The inorganic filler is a particulate inorganic compound, and examples thereof include solid flame retardants, inorganic fillers other than solid flame retardants, etc. The solid flame retardant is a flame retardant that is solid at 23° C., and examples thereof include antimony-containing flame retardants such as antimony oxide, antimonate, and pyroantimonate, metal hydroxide-based flame retardants such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide, boron-containing flame retardants such as lithium borate and sodium borate, phosphinic acid-based flame retardants, phosphate-containing flame retardants, bromine-containing flame retardants, and red phosphorus.
In addition, examples of inorganic fillers other than solid flame retardants include silica, diatomaceous earth, alumina, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, basic magnesium carbonate, calcium carbonate, magnesium carbonate, barium carbonate, dawsonite, hydrotalcite, calcium sulfate, barium sulfate, potassium salts of calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass beads, silica paln, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon paln, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, various magnetic powders, and fly ash.

The flame-retardant urethane resin composition may contain other additives, such as phenol-based, amine-based, or sulfur-based antioxidants, heat stabilizers, light stabilizers, metal damage inhibitors, antistatic agents, crosslinking agents, lubricants, softeners, pigments, dyes, and tackifying resins, to the extent that the effects of the present invention are not impaired.

The flame-retardant urethane resin composition of the present invention may be a one-component type, but the flame-retardant urethane resin composition of the present invention cures by the reaction of the polyol compound and the polyisocyanate compound, so its viscosity changes over time. Therefore, before using the composition, the composition is divided into two or more parts to prevent the composition from curing by reaction. When using the composition, it is preferable to mix the two or more divided parts. Specifically, a two-component type in which the composition is divided into a polyol composition containing a polyol compound and a polyisocyanate composition containing a polyisocyanate is preferable. In addition, the flame-retardant urethane resin composition referred to in this specification includes a composition divided into two or more parts when it is divided into two or more parts, such as a two-component type.

The liquid flame retardant, catalyst, and blowing agent may be mixed with a polyol compound or with a polyisocyanate, but from the viewpoint of storage stability, it is preferable to mix them with a polyol compound to form a polyol composition. That is, in the flame-retardant urethane resin composition, the polyol composition may contain a polyol compound, a liquid flame retardant, a catalyst, and a blowing agent. In addition, when the flame-retardant urethane resin composition contains a foam stabilizer or other additives, these may also be contained in the polyol composition.
In addition, the polyol composition constituting the composition preferably has a viscosity of 1500 mPa·s or less, more preferably 1000 mPa·s or less, from the viewpoint of facilitating kneading when forming a polyurethane foam from the composition. The viscosity is, for example, 50 mPa·s or more. The viscosity of the polyol composition is a viscosity at 20°C, and can be measured by the method described in the examples below.

The polyol composition constituting the flame-retardant urethane resin composition of the present invention preferably has a moisture content of 0.2% or more, more preferably 0.5% or more, as measured by a Karl Fischer apparatus, from the viewpoint of improving the foamability of the composition. In addition, from the viewpoint of foamability and flame retardancy, the moisture content is preferably 6% or less, more preferably 4% or less.

[Polyurethane foam]
The polyurethane foam formed from the flame-retardant urethane resin composition of the present invention is formed from the above-mentioned flame-retardant urethane resin composition, and specifically, is obtained by foaming and curing the flame-retardant urethane resin composition.

<Nurate content>
The flame-retardant urethane resin composition of the present invention is less likely to form isocyanurate rings during foaming, making it easier to suppress two-stage foaming. Therefore, the polyurethane foam formed from the flame-retardant urethane resin composition of the present invention has a low degree of nurate conversion.
The degree of nuration of the polyurethane foam is preferably 1.2 or less, and more preferably 0.9 or less.

The degree of nurate conversion is the ratio (Ib/Ia) of the maximum peak intensity Ib at 1390 to 1430 cm ^{−1 when the average intensity at 1900 to 2000 cm −1 is} set to zero to the maximum peak intensity Ia at 1500 to 1520 cm ⁻¹ when the average intensity at 1900 to 2000 cm ⁻¹ is set to zero, obtained by measuring the infrared absorption spectrum of the polyurethane foam. The infrared absorption spectrum is measured by the ATR method (attenuated total reflection method) for a portion of the polyurethane foam at a depth of 5 mm to 10 mm from the surface layer.
Here, the intensity in the infrared absorption spectrum means infrared absorption intensity. In the infrared absorption spectrum, the absorption at 1400 cm ⁻¹ is due to an isocyanurate bond, and the absorption at 1510 cm ⁻¹ is due to a urethane bond.

<Density>
The density of the polyurethane foam is not particularly limited, but is preferably in the range of 20 to 200 kg/ ^m3 . By setting the density to 200 kg/m3 ^or less, the polyurethane foam becomes lightweight and the workability to structures is improved. Furthermore, by setting the density to 20 kg/m3 or ^more , the desired flame retardancy is easily achieved. From these viewpoints, the density of the polyurethane foam is more preferably in the range of 20 to 100 kg/ ^m3 , and further preferably in the range of 23 to 80 kg/ ^m3 . The density of the polyurethane foam can be measured in accordance with JIS K7222.

<Hot steel ball evaluation>
The polyurethane foam made of the flame-retardant urethane resin composition of the present invention preferably has a steel ball sinking distance of 10 mm or less in a hot steel ball test. When the steel ball sinking distance is 10 mm or less, the polyurethane foam is less likely to spread fire when exposed to a fire or the like, and the spread of fire can be effectively prevented.
The hot steel ball evaluation may be carried out according to the procedure described in the Examples.

The steel ball sinking distance in the above hot steel ball evaluation can be adjusted to the desired value by adjusting the type of polyol compound contained in the flame-retardant urethane resin composition, the amount of flame retardant and water, the type and amount of catalyst, the isocyanate index, etc.

In the above hot steel ball evaluation, a cavity is formed in the test specimen from the top surface to the inside due to the sinking of the steel ball. The sinking distance of the steel ball means the maximum distance of the cavity in the vertical direction to the top surface of the test specimen. Note that the part that has been discolored by heat but has retained its shape is not included in the measurement of the sinking distance.
In addition, the sinking distance of a steel ball in the hot steel ball evaluation of the polyurethane foam made of the above-mentioned flame-retardant urethane resin composition is determined by producing a polyurethane foam from the flame-retardant urethane resin composition under the conditions described in the Examples, and measuring the polyurethane foam.

The foam of the present invention is not particularly limited, but when it is divided into two or more components, such as a two-component flame-retardant urethane resin composition, it can be obtained by, for example, preparing a polyol composition and a polyisocyanate composition, each of which is prepared by mixing the components in advance, mixing them, and foaming them. The components can be mixed and foamed by a known method. For example, it can be obtained using a known device such as a high-pressure foaming machine, a low-pressure foaming machine, a spray foaming machine, or a hand mixer. In the case of a one-component type, a method of foaming a flame-retardant urethane resin composition obtained by mixing the components constituting the flame-retardant urethane resin composition by a known method can be mentioned.

<Applications>
The applications of the flame-retardant urethane resin composition of the present invention and the above-mentioned polyurethane foam are not particularly limited, but they can be used for filling cavities in structures such as buildings, furniture, automobiles, trains, ships, etc., or for spraying onto such structures. Among these, the application of spraying onto structures, i.e., spraying, is preferred.
Spraying can be carried out using a spraying device (e.g., A-25 manufactured by GRACO) and a spray gun (e.g., D-gun manufactured by Gasmar). Spraying can be carried out by adjusting the temperature of the polyol composition and the polyisocyanate composition contained in separate containers in the spraying device, mixing them by collision at the tip of the spray gun, and turning the mixed liquid into mist by air pressure. The spraying device and the spray gun are well known, and commercially available products can be used. Furthermore, the temperature setting and pressure of the raw liquid can be the same as those for spraying general urethane foam.

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

Details of each component used in each example and comparative example are as follows.
<Polyol Compound>
(i) Aromatic polyester polyol/p-phthalic acid-based polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: RFK-505, hydroxyl value = 250 mg KOH/g)
(ii) Bromine-containing aromatic polyether polyol (containing phosphoric acid ester A): manufactured by Wanka Chemical Co., Ltd., product name: FR-130, an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton, a mixture containing 70% by mass of a bromine-based polyol component and 30% by mass of a liquid phosphoric acid ester A component, a hydroxyl value of 110 mg KOH/g
(iii) Aromatic polyether polyol/Mannich-based polyether polyol (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: DK3776S, hydroxyl value = 350 mg KOH/g)

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

<Foam stabilizer>
・Silicone foam stabilizer (Toray Dow Corning Co., Ltd., product name: SH-193)
<Catalyst>
(i) Urethane catalyst/amino compound 1: N,N-dimethylcyclohexylamine (manufactured by Air Products, product name "PC-8")
Amino compound 2: 1,2-dimethylimidazole (Kao Corporation, product name "Kao Raiser No. 390")
Bismuth compound: Bismuth 2-ethylhexanoate (manufactured by Nitto Kasei Co., Ltd., product name: Bi28)
(ii) Trimerization catalyst/alkali metal salt Potassium 2-ethylhexanoate (manufactured by Toei Kako Co., Ltd., product name: potassium hexoate 15%)
<Foaming Agent>
・Water ・HFO-1233zd <hydrofluoroolefin> (manufactured by Honeywell, product name: Solstice LBA)

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

Measurements and evaluations were carried out using the following methods:

[Viscosity of polyol composition]
The viscosity of the polyol composition was measured at 25° C. using a Brookfield viscometer.
○: Viscosity is 1500 mPa·s or less ×: Viscosity is more than 1500 mPa·s [Moisture content]
The polyol composition was measured using a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd., product name: MKV-710).

[Nuration degree]
The degree of nuration of the polyurethane foams produced in each of the Examples and Comparative Examples was measured. The degree of nuration was measured using an infrared spectrophotometer ("Nicolet is5" manufactured by Thermo Fisher Scientific Co.) according to the method described in the specification.

[Hot steel ball evaluation]
For each of the polyurethane foams produced in the Examples and Comparative Examples, the sinking distance and fusion diameter distance of the steel ball were measured by the following procedures (1) to (3).
(1) The polyurethane foam is cut into a rectangular parallelepiped with side dimensions of 100 mm x 100 mm x 60 mm to prepare a test specimen.
(2) A steel ball having a diameter of 10.0 mm and a weight of 4.15 g was placed in an electric furnace set to a temperature of 800° C., and left for 10 minutes or more until the entire steel ball was uniformly heated and turned red, and the temperature of the steel ball was 800° C. The steel ball was a new one.
(3) In an atmosphere of 23° C., the steel ball heated in (2) above is immediately placed on the center of the upper part of the test piece in (1) above and left there until the steel ball has completely sunk in. Then, the cross section of the sufficiently cooled test piece is cut and the sinking distance of the steel ball is measured.
In this hot steel ball evaluation, the time from heating the steel ball to placing it on the test piece is within one second. The steel ball used is made of SUS304.
Regarding the electric furnace, for example, a small programmable electric furnace (product name: MMF-1, manufactured by AS ONE Corporation) with inner dimensions of 120 mm×150 mm×100 mm was used.
From the sinking distance of the steel ball obtained by the above procedure, the quality of the flame-proofing property was judged as follows.

<Hot steel ball evaluation criteria>
・Sinking distance of steel ball 〇・・Sinking distance of steel ball is 10mm or less ×・・Other than the above 〇

[Combustion evaluation according to UL94 standard]
The polyurethane foams prepared in each of the Examples and Comparative Examples were cut out to obtain measurement samples measuring 125 mm x 13 mm x 13 mm, and combustion tests were conducted in accordance with the UL94 standard. The flame retardancy grades were expressed as V-0, V-1, and V-2, in descending order of flame retardancy. The combustion test was conducted five times, and samples that satisfied the V-0 grade in all five tests were evaluated as "◯", and samples that did not satisfy the V-0 grade even once were evaluated as "X".

[Foaming behavior]
The foaming behavior was judged by visual observation. Between the cream time and the time when foaming stops (rise time), the foaming progressed smoothly and was marked with a circle, while the foaming speed showed a sudden change (two-stage foaming) and was marked with a cross. In addition to the above evaluation method, the foaming behavior can be evaluated using a rise curve. The rise curve is a graph obtained by plotting the time from mixing the polyol composition and the polyisocyanate composition on the horizontal axis and the foaming height of the foam on the vertical axis. An example of an apparatus for evaluating the rise curve is the "FOAMAT" manufactured by FORMAT. The rise curve of the foaming agent that foams smoothly is parabolic, but the foaming height of the foaming agent that foams in two stages stagnates once, then starts to foam again and the height changes.

[Examples 1 to 3, Comparative Examples 1 to 2]
According to the formulation in Table 1, each component constituting the polyol composition was weighed into a 1000 mL polypropylene beaker and stirred with a hand mixer at 20° C. for 10 seconds to prepare a polyol composition. The polyol composition was then cooled to 10° C., and a polyisocyanate similarly adjusted to 10° C. was added to the polyol composition to prepare a flame-retardant urethane resin composition, which was then stirred with a lab-di spar for 3 seconds to prepare a polyurethane foam. The polyurethane foam was used to carry out the above-mentioned hot steel ball evaluation and combustion evaluation.

The polyurethane foam obtained was used to carry out the above-mentioned evaluations. The evaluation results for each item are shown in Table 1.

The parts by mass of each catalyst are parts by mass of the product.
The number in parentheses next to the product name is the hydroxyl value (mgKOH/g).
Since FR-130 is a mixed liquid of a polyol compound and a phosphate ester, the parts by mass of each of the polyol compound and the phosphate ester contained in FR-130 are shown, and the parts by mass of the product are shown in parentheses.

As described above, the flame-retardant urethane resin compositions of the Examples that satisfied the requirements of the present invention formed polyurethane foams without two-stage foaming, and the polyurethane foams had excellent flame retardancy. On the other hand, in the Comparative Examples that did not satisfy the requirements of the present invention, two-stage foaming occurred during foaming, or the polyurethane foams had poor flame retardancy.

Claims (9)

A flame-retardant urethane resin composition for forming a heat insulating material, comprising a polyol compound, a polyisocyanate compound, a liquid flame retardant, a foaming agent, and a catalyst,
the catalyst includes a urethanization catalyst, and the content of the trimerization catalyst is 3 parts by mass or less based on 100 parts by mass of the polyol compound;
At least one of the polyol compounds is a bromine-containing polyol,
The content of the liquid flame retardant is 20 to 120 parts by mass relative to 100 parts by mass of the polyol compound,
A flame-retardant urethane resin composition for forming a heat insulating material, wherein the viscosity of a polyol composition constituting the flame-retardant urethane resin composition for forming a heat insulating material at 20°C is 1500 mPa·s or less (excluding those containing a sulfur-containing aromatic diamine) . The flame-retardant urethane resin composition for forming a heat insulating material according to claim 1, wherein the bromine-containing polyol has a basic skeleton of bisphenol A. The flame-retardant urethane resin composition for forming a heat insulating material according to claim 1 or 2, which contains 80 parts by mass or more of an aromatic ring-containing polyol per 100 parts by mass of a polyol compound. The flame-retardant urethane resin composition for forming a heat insulating material according to any one of claims 1 to 3, having an isocyanate index of 90 to 700. The flame-retardant urethane resin composition for forming a heat insulating material according to any one of claims 1 to 4, wherein the moisture content of the polyol composition constituting the flame-retardant urethane resin composition for forming a heat insulating material is 0.2% or more as measured by a Karl Fischer measuring device. The flame-retardant urethane resin composition for forming a heat insulating material according to any one of claims 1 to 5, which contains 30 parts by mass or more of the bromine-containing polyol per 100 parts by mass of the polyol compound. The flame-retardant urethane resin composition for forming a heat insulating material according to any one of claims 1 to 6, which is used for spray applications. The flame-retardant urethane resin composition for forming a heat insulating material according to any one of claims 1 to 7, wherein the content of the inorganic filler is 5 mass% or less based on the total amount of the flame-retardant urethane resin composition for forming a heat insulating material. An insulating material formed from the flame-retardant urethane resin composition for forming insulating materials according to any one of claims 1 to 8.