JP7658732B2 - Flame-retardant urethane resin composition and polyurethane foam - Google Patents

Description

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

Taking advantage of its excellent insulating properties, polyurethane foam is used to insulate and prevent condensation in various structures, such as ceilings, roofs, and walls of buildings, including apartment complexes and other collective housing, 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 deformation of the foam shape 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 forming a polyurethane foam which is suppressed from undergoing two-stage expansion and also has excellent flame retardancy.

As a result of intensive research, the present inventors have found that the above problems can be solved by a flame-retardant urethane resin composition comprising a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, a foaming agent, and additive A, wherein additive A is a solid flame retardant containing a phosphorus element, and have completed the present invention. That is, the present invention provides the following [1] to [9].
[1] A flame-retardant urethane resin composition comprising a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, a foaming agent, and additive A, wherein additive A is a solid flame retardant containing a phosphorus element.
[2] The flame-retardant urethane resin composition according to the above [1], wherein the additive A is at least one selected from red phosphorus, a phosphazene derivative, and a phosphate.
[3] The flame-retardant urethane resin composition according to the above [1] or [2], wherein, per 100 parts by mass of the polyol compound, the amount of the polyol having an aromatic ring is 30 parts by mass or more.
[4] The flame-retardant urethane resin composition according to any one of the above [1] to [3], wherein the catalyst contains a bismuth compound.
[5] The flame-retardant urethane resin composition according to any one of the above [1] to [4], which is substantially free of a trimerization catalyst.
[6] The flame-retardant urethane resin composition according to any one of [1] to [5] above, having an isocyanate index of 300 or less.
[7] The flame-retardant urethane resin composition according to any one of [1] to [6] above, which is for spray application.
[8] A polyurethane foam formed from the flame-retardant urethane resin composition according to any one of [1] to [7] above.
[9] The polyurethane foam according to the above [8], having a degree of nurate conversion of 1.0 or less.
The degree of nurate conversion is the ratio (Ib/Ia) of the maximum peak intensity Ib from 1390 to 1430 cm ⁻¹ to the maximum peak intensity Ia from 1500 to 1520 cm ⁻¹ when the average intensity from 1900 to 2000 cm ⁻¹ is set to zero when the infrared absorption spectrum of the polyurethane foam is measured.

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.

The flame-retardant urethane resin composition of the present invention contains a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, a foaming agent, and additive A, which is a solid flame retardant containing elemental phosphorus.
In order to improve flame retardancy, the flame-retardant urethane resin composition of the present invention uses a liquid flame retardant in combination with Additive A. When these are used in combination, it is possible to improve the flame retardancy of the polyurethane foam without increasing the degree of nurate conversion, and it is therefore believed that two-stage foaming can also be suppressed.

[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 3 to 60 parts by mass, more preferably 5 to 40 parts by mass, and further preferably 10 to 30 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. 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 is easily produced.

[Additive A]
The flame-retardant urethane resin composition of the present invention contains additive A, which is a solid flame retardant containing a phosphorus element. By using additive A in combination with the liquid flame retardant, the flame retardancy of the polyurethane foam formed is effectively increased. In addition, since the flame retardancy of the polyurethane foam is improved by using additive A in combination with the liquid flame retardant, a polyurethane foam with a low degree of nurate is obtained. Therefore, two-stage foaming during foaming is also suppressed, and the polyurethane foam formed on a structure has good adhesion to the structure.

Additive A is a solid flame retardant containing elemental phosphorus. Here, the solid flame retardant is a flame retardant that is solid at 23°C. As the solid flame retardant containing elemental phosphorus, at least one selected from red phosphorus, phosphazene derivatives, and phosphates is preferred. Among these, red phosphorus is preferred from the viewpoint of the effect of improving flame retardancy.

(Red phosphorus)
The red phosphorus may be made of simple red phosphorus, or may be red phosphorus mixed with or coated with a resin, a metal hydroxide, a metal oxide, or the like.

(Phosphate)
The phosphate is a salt of phosphoric acid and at least one metal or compound selected from the group consisting of metals of Groups IA to IVB of the periodic table, ammonia, aliphatic amines, and aromatic amines.
The phosphoric acid is not particularly limited, and examples thereof include various phosphoric acids such as monophosphoric acid, pyrophosphoric acid, and polyphosphoric acid.
Examples of the metals in Groups IA to IVB of the periodic table include lithium, sodium, calcium, barium, iron (II), iron (III), aluminum, etc. Examples of the aliphatic amines include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine, etc. Examples of the aromatic amines include pyridine, triazine, melamine, etc.
Specific examples of phosphates include monophosphates such as aluminum triphosphate, pyrophosphates, polyphosphates, etc. Here, the polyphosphates are not particularly limited, but include, for example, ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium amide polyphosphate, aluminum polyphosphate, etc. Among these, ammonium polyphosphate is preferred.
The above phosphates may be subjected to known water resistance improving treatments such as treatment with a silane coupling agent or coating with a melamine resin.

(Phosphazene Derivatives)
The phosphazene derivative is an organic compound having a -P=N- bond in the molecule, and may be either linear or cyclic.
As the phosphazene derivative, those represented by the following general formula (1) are preferred because they have a relatively high decomposition temperature.

In the above formula (1), R ₁ to R ₆ each independently represent an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an amino group, or a halogen atom.
An example of such a phosphazene compound is "SPB-100" commercially available from Otsuka Chemical Co., Ltd.

The content of additive A in the present invention is preferably 5 to 80 parts by mass, more preferably 8 to 60 parts by mass, even more preferably 10 to 40 parts by mass, and even more preferably 20 to 40 parts by mass, relative to 100 parts by mass of the polyol compound. When the content of additive A is equal to or greater than these lower limits, the flame retardancy of the polyurethane foam is likely to be improved. When the content of additive A is equal to or less than these upper limits, foaming is not inhibited, and polyurethane foam can be easily produced.

From the viewpoint of improving the flame retardancy of the polyurethane foam, it is preferable that additive A has a decomposition temperature of 270°C or higher, and more preferably 300°C or higher. The decomposition temperature means the temperature at which weight begins to change on the temperature-weight change curve when measured in an air atmosphere using TG/DTA (two-stage differential thermal analyzer).

The mass ratio of additive A to the liquid flame retardant (additive A/liquid flame retardant) is preferably 0.1 to 10, more preferably 0.5 to 5, and even more preferably 0.8 to 3.

[Polyol compound]
The polyol compound contained in the flame-retardant urethane resin composition of the present invention is not particularly limited, but for example, polyester polyol, polyether polyol, etc. are preferably used. Among them, from the viewpoint of foam formation, particularly from the viewpoint of forming a desired foam without using a trimerization catalyst as described later, it is preferable to use polyether polyol.
From this viewpoint, out of 100 parts by mass of the polyol compound, it is preferable that the polyether polyol be 20 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 80 parts by mass or more, and particularly preferably 100 parts by mass.
When two or more kinds of polyol compounds are used, the hydroxyl value of the polyol compounds may be an average hydroxyl value according to the blending ratio of the two or more kinds of polyol compounds.
For example, when two types of polyols, polyol (d1) and polyol (d2), are used as the polyol compounds, the average hydroxyl value is represented by the following formula, where the hydroxyl value of polyol (d1) is _X1 , the blending ratio is _m1 , and the hydroxyl value of polyol (d2) is _X2 , and the blending ratio is _m2 . The blending ratio is based on mass.
Average hydroxyl value (mgKOH/g)= _X1 ×( _m1 /( _m1 + _m2 ))+ _X2 ×( _m2 /( _m1 + _m2 ))
The average hydroxyl value of the polyol compound used in the present invention is preferably from 200 to 800 mgKOH/g, more preferably from 250 to 600 mgKOH/g, and even more preferably from 300 to 500 mgKOH/g, from the viewpoint of improving the flame retardancy of the polyurethane foam.

(Polyether polyol)
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. 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.

(Polyester polyol)
Examples of polyester polyols include aromatic polyester polyols, which are polyester polyols having an aromatic ring, and aliphatic polyester polyols. In consideration of the flame retardancy of the resulting polyurethane foam, it is preferable to use aromatic polyester polyols. 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. Among these, from the viewpoint of enhancing the flame retardancy of the polyurethane foam, the polyester polyol is preferably a phthalic acid-based polyester polyol, which is a condensate of phthalic acid and a glycol, and more preferably includes 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, and diethylene glycol.

The hydroxyl value of the polyester polyol is preferably 100 to 500 mg KOH/g, and more preferably 150 to 450 mg KOH/g.

In addition, from the viewpoint of improving the flame retardancy of the polyurethane foam, the polyol compound is preferably a polyol having an aromatic ring, and in particular, from the viewpoint of facilitating foam formation, it is preferable that the polyol compound is a polyether polyol having an aromatic ring.
From the viewpoint of improving the flame retardancy of the resulting polyurethane foam, the content of the polyol having an aromatic ring is preferably 30 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of the polyol compound.
From the viewpoint of flexibility of the resulting polyurethane foam, the content of the polyol having an aromatic ring is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, per 100 parts by mass of the polyol compound.

[Polyisocyanate compound]
As the polyisocyanate compound, 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 its ease of handling, rapid reaction, excellent physical properties of the resulting polyurethane foam, and low cost. As the liquid MDI, crude MDI (also called polymeric MDI) can be mentioned. 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 be used. In addition, 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 polyol in advance. In addition to liquid MDI, other polyisocyanate compounds may be used in combination, and as the polyisocyanate compounds to be used in combination, any polyisocyanate compounds known in the technical field of polyurethanes can be used without any limitations.

The isocyanate index of the flame-retardant urethane resin composition is preferably not more than 300, more preferably not more than 240, and even more preferably not more than 180. When the isocyanate index is not more than these upper limit values, two-stage foaming during foam formation is easily suppressed.
The isocyanate index of the flame-retardant urethane resin composition is preferably 80 or more, more preferably 90 or more, and even more preferably 100 or more, from the viewpoint of properly forming a polyurethane foam.
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 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 5 parts by mass or less per 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 per 100 parts by mass of the polyol compound. From such a viewpoint, the catalyst in the present invention is preferably composed only of a urethane catalyst (including resinification and foaming).

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, tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, tripropylamine, and acid blocked products thereof.
As the amino compound, an imidazole-based compound is preferable, but it is also preferable to use an imidazole-based compound in combination with a tertiary amine compound other than the imidazole-based compound. As the tertiary amine compound, N,N-dimethylcyclohexylamine and the like are preferable.

Examples of tin compounds include stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, etc. Examples of bismuth compounds 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.

From the viewpoint of improving the foaming properties when a polyurethane foam is formed by spraying the flame-retardant urethane resin composition, the catalyst in the present invention preferably contains the above-mentioned bismuth compound, preferably a combination of a bismuth compound and an amino compound, and more preferably a combination of a bismuth compound and an imidazole compound.
When the bismuth compound and the amino compound are used in combination, the mass ratio of the amino compound to the bismuth compound (mass of amino compound/mass of bismuth compound) is preferably 0.1 to 100, more preferably 0.3 to 50, and even more preferably 0.5 to 30.

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 10 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, and 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 more 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 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 50 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 70 parts by mass, more preferably 8 to 58 parts by mass, and even more preferably 18 to 48 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.
As the water used as the blowing agent, for example, ion-exchanged water, distilled water, etc. can be appropriately used. The amount of water per 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, from the viewpoint of adjusting the density of the polyurethane foam to a desired range.

[Foam stabilizer]
The flame-retardant urethane resin composition may contain a foam stabilizer. As the foam stabilizer, a compound having a polar part and a non-polar part in the molecule and having a surface active effect can be suitably used. As the foam stabilizer, for example, a silicone foam stabilizer such as organopolysiloxane can be mentioned. In addition, as the silicone foam stabilizer, one containing a graft copolymer of polydimethylsiloxane and polyethylene glycol can be used.
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.

In addition to the above-mentioned components, 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 is cured by the reaction of the polyol compound and the polyisocyanate compound, so that its viscosity changes over time. Therefore, before using the composition, the composition is divided into two or more parts to prevent the composition from reacting and curing. Then, when using the composition, it is preferable to mix the two or more divided parts of the composition.
When the flame-retardant urethane resin composition is divided into two or more components, the components should be divided so that each component of the flame-retardant urethane resin composition divided into two or more components does not start curing alone, but the curing reaction starts after each component of the flame-retardant urethane resin composition is mixed. Usually, the flame-retardant urethane resin composition is divided into a polyol composition containing a polyol compound and a polyisocyanate composition containing a polyisocyanate compound.

The above-mentioned blowing agent, catalyst, liquid flame retardant, additive A, and foam stabilizer, which is blended as necessary, may be contained in the polyol composition, may be contained in the polyisocyanate composition, or may be provided separately from the polyol composition and the polyisocyanate composition, but are preferably contained in the polyol composition.

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

(Nuration degree)
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.

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.

(Application)
The applications of the flame-retardant urethane resin composition of the present invention and the polyurethane foam obtained by foaming the composition are not particularly limited, and the composition 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 composition is preferably used for spraying onto structures, i.e., as a flame-retardant urethane resin composition for spraying.
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) Polyether polyol having an aromatic ring/tolylene diamine-based polyether polyol (manufactured by Sumika Covestro Urethane Co., Ltd., product name: Polyol H422, hydroxyl value = 410 mg KOH/g)
(ii) Polyether polyol having no aromatic ring - Pentaerythritol-based polyether polyol (manufactured by Sumika Covestro Urethane Co., Ltd., product name: O487, hydroxyl value = 410 mg KOH / g)
(iii) Polyester polyol having an aromatic ring: p-phthalic acid-based polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: RFK-509
, hydroxyl value = 200 mg KOH / g)

<Additive A>
・Red phosphorus (manufactured by Rinkagaku Kogyo Co., Ltd., product name: Nova Excel 140, powder, decomposition temperature 490°C)
Ammonium polyphosphate (Clariant Chemicals, product name: EXOLIT AP422, powder, decomposition temperature 275°C or higher)

<Liquid flame retardant>
Phosphate ester flame retardant Tris(β-chloropropyl)phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name: TMCPP)
Phosphate ester flame retardant Tricresyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name: TCP, liquid, decomposition temperature 433°C)

<Foam stabilizer>
・Silicone foam stabilizer (Toray Dow Corning Co., Ltd., product name: SH-193)

<Catalyst>
(i) Urethane catalyst/amino compound N,N-dimethylcyclohexylamine (manufactured by Evonik, product name "PC-8") concentration 90 to 100% by mass
Amino compound: 1,2-dimethylimidazole (Kao Corporation, product name "Kao Raiser No. 390"), concentration 65 to 75% by mass
Bismuth compound: bismuth 2-ethylhexanoate (manufactured by Nitto Kasei Co., Ltd., product name: Bi28), concentration 81 to 90% by mass
(ii) Trimerization catalyst/alkali metal salt Potassium 2-ethylhexanoate (manufactured by Toei Kako Co., Ltd., product name: potassium hexoate 15%), concentration 75% by mass
<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)

[Nuration Degree of Polyurethane Foam]
The degree of nuration was measured for the polyurethane foams produced in each of the Examples and Comparative Examples. The degree of nuration is the ratio (Ib/Ia) of the maximum peak intensity Ib at 1390 to 1430 cm ⁻¹ when the average intensity of 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 of 1900 to 2000 cm ⁻¹ is set to zero, measured by measuring the infrared absorption spectrum of the polyurethane foam. The infrared absorption spectrum was 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.
The measurement was carried out using an infrared spectrophotometer ("Nicolet is5" manufactured by Thermo Fisher Scientific).

[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 a combustion test was carried out according to 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 carried out five times, and samples that met the V-0 grade in all five tests were rated as "◯", samples that met the V-0 grade one to four times were rated as "△", and samples that did not meet the V-0 grade even once were rated as "X".

[Foaming behavior]
The foaming behavior was judged by visual observation. Between the time immediately before the flame-retardant urethane composition foams and expands (cream time) and the time when foaming stops (rise time), the foaming progressed smoothly and the foaming speed changed suddenly (two-stage foaming) and was marked with a circle and a cross, respectively. 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 smooth foaming is parabolic, but the foaming height of the two-stage foaming stagnates once, then starts to foam again and the height changes.

[Examples 1 to 4, Comparative Examples 1 to 3]
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. The composition was 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 evaluations.

The parts by mass of each catalyst are parts by mass of the product.
The numerical value in parentheses for the polyol compound is the hydroxyl value (mg KOH/g).

The flame-retardant urethane resin compositions of the Examples which 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 which did not satisfy the requirements of the present invention, two-stage foaming occurred during foaming, or the polyurethane foams had poor flame retardancy.

Claims (7)

The composition includes a polyol compound, a polyisocyanate compound, a liquid flame retardant, a catalyst, a foaming agent, and an additive A,
The polyol compound contains 80 parts by mass or more of polyether polyol and 30 parts by mass or more of polyether polyol having an aromatic ring, per 100 parts by mass of the polyol compound;
the catalyst includes a urethanization catalyst, and the content of the trimerization catalyst is 5 parts by mass or less based on 100 parts by mass of the polyol compound;
The blowing agent comprises a hydrofluoroolefin;
The additive A is a solid flame retardant containing a phosphorus element,
The content of the liquid flame retardant is 3 to 60 parts by mass based on 100 parts by mass of the polyol compound,
A flame-retardant urethane resin composition for forming a heat insulating material by spraying onto a surface of a building , characterized in that the content of the additive A is 5 to 80 parts by mass per 100 parts by mass of the polyol compound. 2. The flame-retardant urethane resin composition for forming a heat insulating material by spraying it onto the surface of a building according to claim 1, wherein the additive A is at least one selected from red phosphorus, a phosphazene derivative, and a phosphate. 3. The flame-retardant urethane resin composition for forming a heat insulating material by spraying it onto a surface of a building according to claim 1, wherein the catalyst contains a bismuth compound. 4. The flame-retardant urethane resin composition for forming a heat insulating material by spraying it onto a surface of a building according to claim 1, wherein the catalyst contains an imidazole compound. 5. The flame-retardant urethane resin composition for forming a heat insulating material by spraying it onto the surface of a building according to claim 1, having an isocyanate index of 300 or less. A polyurethane foam formed from the flame-retardant urethane resin composition for forming a heat insulating material by spraying it onto the surface of a building according to any one of claims 1 to 5. The polyurethane foam according to claim 6, having a degree of nuration of 1.2 or less.
The degree of nurate conversion is the ratio (Ib/Ia) of the maximum peak intensity Ib from 1390 to 1430 cm ⁻¹ to the maximum peak intensity Ia from 1500 to 1520 cm ⁻¹ when the average intensity from 1900 to 2000 cm ⁻¹ is set to zero when the infrared absorption spectrum of the polyurethane foam is measured.