JP7717455B2 - Polyol composition, flame-retardant urethane resin composition, and polyurethane foam - Google Patents

Description

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

Taking advantage of their excellent insulating properties, polyurethane foams are used to insulate and prevent condensation in various structures, such as ceilings, roofs, and walls of buildings such as apartment complexes, detached houses, and commercial buildings. Polyurethane foams are formed, for example, by spraying a urethane resin composition containing a polyol composition and a polyisocyanate composition onto the surface of the structure, followed by foaming and curing.

For example, Patent Document 1 describes an invention relating to a spray-on insulation material made from a rigid polyurethane foam obtained by foaming a liquid mixture containing a polyisocyanate component, a polyol component, water, a catalyst, a foam stabilizer, a flame retardant, and powder. It also indicates that this spray-on insulation material has excellent flame retardancy and dimensional stability.

JP 2010-270877 A

When a polyurethane foam is formed using a composition containing a foam stabilizer, as in Patent Document 1, the foam stabilizer is likely to bleed out onto the surface of the foam, which can cause problems such as contamination of the object of use or making the resulting foam more flammable.
On the other hand, from the viewpoint of solving the problems of bleed-out and flammability, it is conceivable to produce polyurethane foam without using a foam stabilizer. However, it has been found that if a foam stabilizer is not used, the cells forming the polyurethane foam become coarse, such as some of the cells being prone to cracking, and as a result, the thermal insulation properties tend to decrease.
Therefore, an object of the present invention is to provide a polyol composition that can suppress cell coarsening and produce a polyurethane foam with excellent heat insulation properties even when no foam stabilizer is used.

As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by a polyol composition containing a polyol compound, a flame retardant, a catalyst, and a catalyst, wherein the polyol composition does not contain a foam stabilizer and has a moisture content of 1.8 mass% or less, and have completed the present invention. That is, the present invention provides the following [1] to [8].
[1] A polyol composition containing a polyol compound, a liquid flame retardant, a catalyst, and a blowing agent, wherein the polyol composition does not contain a foam stabilizer and has a moisture content of 1.8 mass% or less.
[2] The polyol composition according to [1], wherein the catalyst contains a metal-based urethanization catalyst.
[3] The polyol composition according to any one of [1] and [2], wherein the catalyst contains a trimerization catalyst.
[4] The polyol composition according to any one of [1] to [3], wherein the polyol composition contains a filler.
[5] A flame-retardant urethane resin composition produced by mixing the polyol composition according to any one of [1] to [4] with a polyisocyanate composition containing a polyisocyanate compound, wherein the flame-retardant urethane resin composition does not contain a foam stabilizer.
[6] The flame-retardant urethane resin composition according to [5], wherein the cream time of the flame-retardant urethane resin composition is 10 seconds or less.
[7] The flame-retardant urethane resin composition according to [5] or [6], which is for spray applications.
[8] A polyurethane foam formed by foaming the flame-retardant urethane resin composition according to any one of [5] to [7].

The present invention uses a polyol composition that does not use a foam stabilizer, which prevents the foam stabilizer from bleeding out onto the surface of the polyurethane foam that is formed. Furthermore, by removing foam stabilizer components that could be a flammable element, the polyurethane foam can be prevented from becoming susceptible to combustion. In addition, coarsening of cells can be prevented, resulting in a polyurethane foam with excellent thermal insulation properties.

[Polyol composition]
The present invention relates to a polyol composition containing a polyol compound, a liquid flame retardant, a catalyst, and a blowing agent, which does not contain a foam stabilizer and has a moisture content of 1.8 mass% or less.

<Foam stabilizer>
The polyol composition of the present invention does not contain a foam stabilizer. The absence of a foam stabilizer prevents the foam stabilizer from bleeding out onto the surface of the polyurethane foam formed when, for example, a silicone-based foam stabilizer is used. Furthermore, by removing the foam stabilizer component, which could be a flammable element, the polyurethane foam can be prevented from becoming easily flammable.
The foam stabilizer used herein refers to a foam stabilizer that has a foam-stabilizing function during polyurethane foaming and is generally used in the production of polyurethane foams. Examples of the foam stabilizer include silicone-based foam stabilizers and non-silicone-based foam stabilizers.
The silicone-based foam stabilizer is a compound having a polysiloxane chain and a polyoxyalkylene chain, and may have a block structure of the polysiloxane chain and the polyoxyalkylene chain, or a structure in which a polyoxyalkylene chain is grafted as a side chain to a polysiloxane chain as a main chain. Specific product names of the silicone-based foam stabilizer include SH-193, SF-2937F, and SF-2945F manufactured by Toray Dow Corning Co., Ltd.
The non-silicone foam stabilizer refers to a foam stabilizer other than a silicone foam stabilizer, and examples thereof include acrylic surfactants, etc. Examples of the acrylic surfactants include acrylic polymers having polar groups on the side chains.

<Blowing Agent>
Specific examples of blowing agents include water, low-boiling hydrocarbons, chlorinated aliphatic hydrocarbon compounds, fluorine compounds, hydrochlorofluorocarbon compounds, hydrofluorocarbons, ether compounds, hydrofluoroolefins, etc. Further examples of blowing agents 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).
Examples of the ether compounds include 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, hydrofluoroolefins, water, etc. are preferred as blowing agents, and it is more preferred to use a combination of hydrofluoroolefins and water.

The amount of the hydrofluoroolefin used as the blowing agent is preferably 3 to 60 parts by mass, more preferably 8 to 57 parts by mass, and even more preferably 19 to 49 parts by mass, per 100 parts by mass of the polyol compound, from the viewpoint of achieving a polyurethane foam density within a desired range.
The water used as the blowing agent may be, for example, ion-exchanged water, distilled water, etc. The amount of water per 100 parts by mass of the polyol compound is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.2 to 2.5 parts by mass, from the viewpoint of adjusting the isocyanate index to a certain level or higher and adjusting the density of the polyurethane foam within a desired range.

<Moisture percentage>
The moisture content in the polyol composition of the present invention is 1.8% by mass or less. If the moisture content exceeds 1.8% by mass, the cells in the polyurethane foam may partially crack, resulting in coarse cells and a decrease in heat insulating properties. In light of this, the moisture content is preferably 1.3% by mass or less, and more preferably 1% by mass or less.
The lower limit of the moisture content is not particularly limited, but from the viewpoint of ensuring good foaming properties and sprayability when the polyol composition is mixed with the polyisocyanate composition, it is preferable that the polyol composition contains a certain amount of moisture or more, and the moisture content is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more.
The moisture content is a value measured for the polyol composition using a Karl Fischer moisture content analyzer.

<Polyol Compound>
The polyol compound is not particularly limited, but examples thereof include polyether polyols and polyester polyols. From the viewpoint of improving the flame retardancy of the polyurethane foam, the polyol compound preferably contains a polyester polyol. Also, from the viewpoint of improving the flame retardancy, it is preferable to use a halogen-containing polyol or a phosphorus-containing polyol.
From this viewpoint, it is preferable that the amount of polyester polyol is 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, out of 100 parts by mass of polyol compound.

When two or more types 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 types of polyol compounds.
For example, when two types of polyols (d1) and (d2) are used as the polyol compounds, the average hydroxyl value is expressed by the following formula, where _X1 is the hydroxyl value of polyol (d1), _m1 is the blending ratio, and _X2 is the hydroxyl value of polyol (d2), _m2 is the blending ratio. Note that the blending ratio is based on mass.
Average hydroxyl value (mgKOH/g) = _X1 x ( _m1 /( _m1 + _m2 )) + _X2 x ( _m2 /( _m1 + _m2 ))
The average hydroxyl value of the polyol compound used in the present invention is preferably 100 to 500 mgKOH/g, more preferably 150 to 450 mgKOH/g, and even more preferably 200 to 400 mgKOH/g, from the viewpoint of improving the flame retardancy of the polyurethane foam.
The hydroxyl value is a value measured in accordance with JIS K1557-1:2007.

(Polyester polyol)
The polyester polyol may be a polyester polyol having an aromatic ring or an aliphatic polyester polyol, but when the flame retardancy of the resulting polyurethane foam is taken into consideration, it is preferable to use a polyester polyol having an aromatic ring. The polyester polyol having an aromatic ring 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, the polyol compound preferably contains a phthalic acid-based polyester polyol, which is a condensate of phthalic acid and a glycol, and 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 constituent 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 mgKOH/g, more preferably 150 to 450 mgKOH/g, and even more preferably 200 to 400 mgKOH/g.

(Polyether polyol)
The 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; alkanolamines such as monoethanolamine and diethanolamine); and aromatic amines (e.g., aniline, tolylenediamine, xylylenediamine, diphenylmethanediamine, and Mannich condensation products).
Among these, polyether polyols produced using an initiator having an aromatic ring are polyether polyols having an aromatic ring, for example, polyether polyols produced using an aromatic amine as an initiator are polyether polyols having an aromatic ring. Among 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 a polyether polyol obtained by adding an alkylene oxide 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 this compound with at least one of ethylene oxide and propylene oxide.

The hydroxyl value of the polyether polyol is preferably 200 to 2000 mgKOH/g, and more preferably 300 to 1000 mgKOH/g.

<Catalyst>
The polyol composition contains a catalyst. Examples of the catalyst include a urethanization catalyst, a trimerization catalyst, and a foaming catalyst. The trimerization catalyst promotes trimerization to form an isocyanurate bond. From the viewpoints of improving the flame retardancy of the polyurethane foam and the foaming properties of the flame-retardant urethane resin composition described below, the catalyst preferably contains a trimerization catalyst.

(trimerization catalyst)
Examples of trimerization catalysts that can be used include nitrogen-containing aromatic compounds such as tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, and 2,4,6-tris(dialkylaminoalkyl)hexahydro-S-triazine; alkali metal carboxylates such as potassium acetate, potassium 2-ethylhexanoate, and potassium octoate; tertiary ammonium salts such as trimethylammonium salt, triethylammonium salt, and triphenylammonium salt; and quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium salt, tetraphenylammonium salt, triethylmonomethylammonium salt, and quaternary ammonium salts of carboxylic acids. A preferred example of the carboxylic acid in the ammonium carboxylate is at least one selected from the group consisting of 2-ethylhexanoic acid, 2,2-dimethylpropanoic acid, acetic acid, and formic acid. The trimerization catalysts may be used alone or in combination of two or more, although a combination of two or more is preferred.
The trimerization catalyst is preferably at least one selected from the group consisting of alkali metal carboxylates and quaternary ammonium carboxylates, and it is preferable to use an alkali metal carboxylate and a quaternary ammonium carboxylate in combination.

The content of the trimerization catalyst in the polyol composition is preferably 1 to 30 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the polyol compound.

(Urethanization catalyst)
In the present invention, the catalyst may contain a urethanization catalyst. In this case, it is more preferable that both the trimerization catalyst and the urethanization catalyst are contained.
The urethanization catalyst is a catalyst that promotes the reaction between a polyol compound and a polyisocyanate compound. Specific examples include amino compounds and metal-based urethanization catalysts, with metal-based urethanization catalysts being preferred.

Amino compounds include imidazole-based 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-methylmorpholine bis(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 versions of these. Among amino compounds, imidazole-based compounds are preferred.

Metal-based urethane catalysts include tin compounds, bismuth compounds, and acetylacetone metal salts. Among these, from the viewpoint of further increasing the initial activity of the reaction between the polyol compound and the polyisocyanate compound, one or more selected from bismuth compounds and tin compounds are preferred, with bismuth compounds being more preferred.

Examples of tin compounds include stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, etc. Examples of bismuth compounds include bismuth neodecanoate, bismuth 2-ethylhexanoate, 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.
The catalyst in the present invention preferably contains the above-mentioned bismuth compound from the viewpoint of reacting the polyol composition and the polyisocyanate composition at an appropriate rate.

The content of the urethane catalyst in the polyol composition is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, even more preferably 0.05 to 3 parts by mass, and particularly preferably 0.07 to 1 part by mass, per 100 parts by mass of the polyol compound. When the content of the urethane catalyst is at or above the lower limit, urethane bond formation occurs more easily, the reaction proceeds quickly, and foaming properties are good. On the other hand, when the content of the urethane catalyst is at or below the upper limit, the reaction rate can be more easily controlled, which is preferable.

(Foaming catalyst)
The catalyst used in the polyol composition of the present invention may contain a foaming catalyst. Therefore, the catalyst may contain a trimerization catalyst, a urethanization catalyst, and a foaming catalyst. The use of a foaming catalyst causes the urethane resin composition to foam, improving the foaming properties. Examples of foaming catalysts include amine-based foaming catalysts. The amine-based foaming catalyst is preferably a compound having two or more nitrogen atoms in the molecule, or a compound having one or more nitrogen atoms and one or more oxygen atoms in the molecule, with guanidine derivatives being more preferred.

A guanidine derivative is a compound having a guanidine skeleton, and a specific example thereof is tetraalkylguanidine, which is an N,N,N',N'-tetraalkylguanidine in which a total of four hydrogen atoms bonded to the nitrogen atoms at positions 1 and 3 are each independently substituted with an alkyl group.
Specific examples of tetraalkylguanidines include compounds represented by the following general formula (1).

(In general formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group.)

The alkyl group of R ₁ , R ₂ , R ₃ and R ₄ is, for example, an alkyl group having 1 to 16 carbon atoms, preferably 1 to 4 carbon atoms. The alkyl group may be linear, branched or have a cyclic structure.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, etc. Among these, from the viewpoints of stability and foaming property, a methyl group is preferred, and N,N,N',N'-tetramethylguanidine in which the above four alkyl groups are all methyl groups is more preferred.
From the viewpoint of foamability, the content of the foaming catalyst in the polyol composition is preferably 0.02 to 10 parts by mass, more preferably 0.04 to 5 parts by mass, and even more preferably 0.06 to 2 parts by mass, per 100 parts by mass of the polyol compound.

<Liquid flame retardant>
The polyol composition of the present invention contains a liquid flame retardant from the viewpoint of improving the flame retardancy of the resulting polyurethane foam. Among liquid flame retardants, phosphate ester flame retardants are particularly preferred. The use of a phosphate ester flame retardant can improve the flame retardancy of the polyurethane foam and also allows the viscosity of the polyol composition to be appropriately controlled even when a filler, described below, is used. Here, the liquid flame retardant is a flame retardant that is liquid at 23°C.

Examples of the phosphate flame retardant include 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 (trade name: CR-733S), bisphenol A polycresyl phosphate (trade name: CR-741), and aromatic condensed phosphate ester (trade name: CR747).

From the viewpoint of flame retardancy and foaming ability, the content of the liquid flame retardant is preferably 5 to 100 parts by mass, more preferably 12 to 90 parts by mass, even more preferably 20 to 75 parts by mass, and even more preferably 30 to 60 parts by mass, per 100 parts by mass of the polyol compound.

<Filler>
The polyol composition of the present invention may contain a filler. The filler is contained as a solid component in the polyol composition and is generally present in the form of particles or powder. By containing a filler, various physical properties such as mechanical strength and flame retardancy can be improved depending on the type of filler.
The filler may be any component that is solid at room temperature (23° C.) and normal pressure (1 atmosphere) and does not dissolve in the flame-retardant urethane resin composition.

The filler preferably contains a solid flame retardant. Examples of solid flame retardants include boron-based flame retardants, bromine-based flame retardants, phosphate-containing flame retardants, antimony-containing flame retardants, phosphinic acid-based flame retardants, metal hydroxide-based flame retardants, red phosphorus, and needle-shaped fillers. Among these, red phosphorus and needle-shaped fillers are preferred from the viewpoint of improving the flame retardancy of polyurethane foam.

(Boron-based flame retardant)
Specific examples of boron-based flame retardants 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, etc. Of these, zinc borate is preferred.

(brominated flame retardants)
The brominated flame retardant is not particularly limited as long as it is a compound containing bromine in its molecular structure, and examples thereof include aromatic brominated compounds.
Specific examples of the aromatic brominated compounds include monomeric organic bromine compounds such as hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis(pentabromophenoxy)ethane, ethylenebis(pentabromophenyl), ethylenebis(tetrabromophthalimide), and tetrabromobisphenol A; polycarbonate oligomers produced using brominated bisphenol A as a raw material; and mixtures of the polycarbonate oligomers with bisphenols. brominated epoxy compounds such as brominated polycarbonates such as copolymers with brominated bisphenol A and epichlorohydrin, diepoxy compounds produced by the reaction of brominated bisphenol A with epichlorohydrin, and monoepoxy compounds obtained by the reaction of brominated phenols with epichlorohydrin; halogenated bromine compound polymers such as poly(brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A, condensates of cyanuric chloride and brominated phenol, brominated (polystyrene), poly(brominated styrene), brominated polystyrenes such as crosslinked brominated polystyrene, and crosslinked or non-crosslinked brominated poly(α-methylstyrene).
Among these, ethylenebis(pentabromophenyl), ethylenebis(tetrabromophthalimide), hexabromobenzene, etc. are preferred.

(Phosphate-containing flame retardants)
Examples of phosphate-containing flame retardants include those containing phosphoric acid and a metal of Groups IA to IVB of the periodic table,
Examples include phosphates formed from salts with at least one metal or compound selected from 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 of 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.
The phosphate-containing flame retardant may be subjected to a known treatment for improving water resistance, such as treatment with a silane coupling agent or coating with a melamine resin.

Specific examples of phosphate-containing flame retardants include monophosphates, pyrophosphates, and polyphosphates.
The monophosphate salt is not particularly limited, but examples thereof include ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; monosodium phosphate;
Sodium salts such as 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 dihydrogen phosphate;
Examples include barium salts such as 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; and zinc salts such as zinc phosphate, zinc phosphite, and zinc hypophosphite.

The polyphosphate is not particularly limited, but examples thereof include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium amide polyphosphate, and aluminum polyphosphate.
The phosphate-containing flame retardants may be used singly or in combination of two or more.

(Antimony-containing flame retardant)
Examples of the antimony-containing flame retardant used in the present invention include antimony oxide, antimonates, and pyroantimonates.
Examples of antimony oxides include antimony trioxide and antimony pentoxide. Examples of antimonate salts include sodium antimonate and potassium antimonate. Examples of pyroantimonate salts include sodium pyroantimonate and
Examples include potassium pyroantimonate.
Preferably, the antimony-containing flame retardant is antimony oxide.
The antimony-containing flame retardants may be used singly or in combination of two or more.

(Phosphinic acid flame retardant)
Examples of phosphinic acid flame retardants include phosphinic acid, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctylphosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid, diphenylphosphinic acid, and bis(4-methoxyphenyl)phosphinic acid.

(metal hydroxide flame retardant)
Examples of metal hydroxide flame retardants include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide, copper hydroxide, vanadium hydroxide, tin hydroxide, etc. The metal hydroxide flame retardants may be used alone or in combination of two or more.

(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.

(Needle filler)
Examples of needle-like fillers include potassium titanate whiskers, aluminum borate whiskers, magnesium-containing whiskers, silicon-containing whiskers, wollastonite, sepiolite, zonolite, elestadite, boehmite, rod-shaped hydroxyapatite, glass fibers, carbon fibers, graphite fibers, metal fibers, slag fibers, gypsum fibers, silica fibers, alumina fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, boron fibers, and stainless steel fibers.
These needle-like fillers can be used alone or in combination of two or more.

The filler may also be an inorganic filler other than the flame retardants listed above. Examples of inorganic fillers that can be used include 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, and fly ash. These inorganic fillers may be used alone or in combination.

The content of the filler is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, and preferably 90 parts by mass or less, more preferably 85 parts by mass or less, relative to 100 parts by mass of the polyol compound.
When the filler content is equal to or greater than these lower limits, the filler can easily exhibit its function according to its type, and when a solid flame retardant is used as the filler, the flame retardancy of the polyurethane foam is likely to be improved. When the filler content is equal to or less than these upper limits, clogging of the spraying device is suppressed, and spraying properties can be improved.

The polyol composition may not contain the above-mentioned fillers. If the polyol composition does not contain fillers, sedimentation is less likely to occur during storage, handling is easier, and wear on equipment used during use can be reduced.

<Other ingredients>
The polyol composition may contain, as needed, one or more additives selected from phenolic, amine, sulfur-based, and other antioxidants, heat stabilizers, metal inhibitors (metal deactivators), antistatic agents, heat and light stabilizers, crosslinking agents, lubricants, softeners, plasticizers, pigments, dyes, tackifying resins, and tackifiers such as polybutene and petroleum resins, within the scope of the present invention.

<Method of producing polyol composition>
There is no particular limitation on the method for producing the polyol composition of the present invention. For example, the polyol composition can be produced by stirring the components at about 20 to 40° C. for about 30 seconds to 20 minutes using a homodisper or the like.

[Flame-retardant urethane resin composition]
The flame-retardant urethane resin composition of the present invention contains the polyol composition containing the above-mentioned polyol compound, flame retardant, catalyst, and blowing agent, and the polyisocyanate composition containing the polyisocyanate compound, and is obtained by mixing these. The polyurethane foam of the present invention is a reaction product obtained by reacting and foaming the flame-retardant urethane resin composition.

<Polyisocyanate Compound>
The polyisocyanate compound contained in the polyisocyanate composition of the present invention can be any of various polyisocyanate compounds having two or more isocyanate groups, such as aromatic, alicyclic, and aliphatic polyisocyanate compounds. The polyisocyanate compounds may be used alone or in combination of two or more.
As the polyisocyanate compound, 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. Examples of liquid MDI include crude MDI (also known as 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" (Nippon Polyurethane Industry Co., Ltd.). Uretonimine-containing MDI (for example, the commercially available product "Millionate MTL" manufactured by Nippon Polyurethane Industry Co., Ltd.) may also be used.
Alternatively, a polyisocyanate compound may be used in which some of the isocyanate active groups in the isocyanate compound have been reacted with a hydroxyl group-containing compound to enhance its affinity with polyols. Liquid MDI may be used in combination with other polyisocyanate compounds, and any polyisocyanate compound known in the polyurethane technical field may be used as the polyisocyanate compound. The polyisocyanate composition may consist solely of a polyisocyanate compound, but may also contain known additives that are used in combination with polyisocyanate compounds.
However, like the polyol composition, the polyisocyanate composition does not contain a foam stabilizer, and therefore the flame-retardant urethane resin composition also does not contain a foam stabilizer.

The mixing ratio of the polyol composition and polyisocyanate composition of the present invention is preferably adjusted so that the isocyanate index of the flame-retardant urethane resin composition is as follows. When the flame-retardant urethane resin composition is used for spray applications, the volume ratio of the polyisocyanate composition to the polyol composition (polyisocyanate composition/polyol composition) is not particularly limited, but is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.

The isocyanate index of the flame-retardant urethane resin composition of the present invention is preferably 150 to 700, and more preferably 200 to 600. When the isocyanate index is equal to or greater than these lower limits, a polyurethane foam having high flame retardancy is easily obtained, while when the isocyanate index is equal to or less than these upper limits, good foamability can be achieved during foam formation.
The isocyanate index (INDEX) is the value obtained by dividing the number of moles of isocyanate groups in a polyisocyanate by the total number of moles of hydroxyl groups in a polyol and active hydrogen groups in water used as a blowing agent, and multiplying the result by 100, and is calculated by the following method.

INDEX = number of equivalents of isocyanate ÷ (number of equivalents of polyol + number of equivalents of water) × 100
where:
Equivalent weight of isocyanate = parts of polyisocyanate used x NCO content (%) x 100/NCO molecular weight Equivalent weight of polyol = OHV x parts of polyol used / molecular weight of KOH, where OHV is the hydroxyl value of the polyol (mg KOH/g).
Equivalent number of water = parts of water used × number of OH groups in 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 the convenience of unit conversion in the above formula, the molecular weight of KOH is set to 56,100, the molecular weight of water is 18, and the number of OH groups in water is 2.

The flame-retardant urethane resin composition of the present invention cures through a reaction between the polyol compound and the polyisocyanate compound, and its viscosity changes over time. Therefore, before using the composition, the polyol composition and the polyisocyanate composition are stored separately to prevent the polyisocyanate and polyol from reacting and curing. Then, when producing a urethane foam, the polyol composition and the polyisocyanate composition are mixed together.

<Cream Time>
The flame-retardant urethane resin composition of the present invention preferably has a cream time of 10 seconds or less. A cream time of 10 seconds or less allows the polyol composition and the polyisocyanate compound to react at an appropriate rate, preventing dripping problems when the polyurethane foam is sprayed onto an object. Furthermore, the low-thermal-conductivity blowing agent (e.g., hydrofluoroolefin) contained in the resin composition can be reduced in scattering and confined within the foam, improving thermal insulation. Taking these points into consideration, the cream time of the flame-retardant urethane resin composition is preferably 8 seconds or less, more preferably 7 seconds or less. The lower limit of the cream time is not particularly limited, but is preferably 1 second or more, more preferably 2 seconds or more.
The cream time can be adjusted to a desired value by adjusting the type and amount of catalyst contained in the polyol composition. The cream time is a value measured by the cup foaming method. Specifically, it is measured as follows.
The liquid temperatures of the polyol composition and polyisocyanate composition constituting the flame-retardant urethane resin composition of the present invention are each adjusted to 10°C. Then, in a room at 23°C, the polyol composition and polyisocyanate composition adjusted to 10°C are poured into a 500 mL cup at a predetermined mixing ratio to give a total mixed solution of 60 g. The mixed solution is then immediately stirred at 8000 rpm for 2 seconds using a Lab-Iso Spa (a high-speed disperser, Homodisper 2.5, manufactured by PRIMIX Corporation). The time when stirring began is designated as the measurement start time (0 seconds). The time (seconds) until the mixed solution changes color and the liquid level begins to rise due to foaming is measured and used as the cream time.
The above-mentioned predetermined mixing ratio means the mixing ratio of the polyol composition to the polyisocyanate composition when preparing the flame-retardant urethane resin composition of the present invention.

<Gel time>
The gel time of the flame-retardant urethane resin composition of the present invention is not particularly limited, but is preferably 20 seconds or less. A gel time of 20 seconds or less provides a good balance between the urethane resin formation rate and the foam stabilization ability, effectively preventing the polyurethane foam from becoming coarse due to partial cell cracking or the like, and makes it easier to maintain heat insulation.
From the viewpoint of improving the heat insulating properties of the polyurethane foam to be formed, the gel time of the flame-retardant urethane resin composition is more preferably 18 seconds or less, and even more preferably 15 seconds or less.
The gel time can be adjusted to a desired value by adjusting the type and amount of catalyst contained in the polyol composition. The gel time is a value measured by the cup foaming method. Specifically, it is measured as follows.
The liquid temperatures of the polyol composition and polyisocyanate composition constituting the flame-retardant urethane resin composition of the present invention are each adjusted to 10°C. Then, in a room at 23°C, the polyol composition and polyisocyanate composition adjusted to 10°C are poured into a 500 mL cup at a predetermined mixing ratio to give a total mixed solution of 60 g. The mixed solution is then immediately stirred at 8000 rpm for 2 seconds using a Lab-Iso Disper (PRIMIX Corporation, high-speed disperser, Homo Disper 2.5). The time when stirring began is designated as the measurement start time (0 seconds). The time (seconds) until the foam begins to form strings when pierced with a stick during foaming is measured, and this is defined as the gel time.
The above-mentioned predetermined mixing ratio means the mixing ratio of the polyol composition to the polyisocyanate composition when preparing the flame-retardant urethane resin composition of the present invention.

[Polyurethane foam]
The polyurethane foam 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.

(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 its application to structures becomes easier. Furthermore, by setting the density to 20 kg/m3 or ^more , the desired flame retardancy is more likely to be exhibited. From these viewpoints, the density of the polyurethane foam is more preferably in the range of 20 to 100 kg/ ^m3 , and even more 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 polyurethane foam of the present invention can be obtained by mixing a polyol composition and a polyisocyanate composition to prepare a flame-retardant urethane resin composition and then foaming the composition. The components can be mixed and foamed using known methods. For example, the foam can be obtained using known devices such as a high-pressure foaming machine, a low-pressure foaming machine, a spray foaming machine, or a hand mixer.

(Application)
The flame-retardant urethane resin composition of the present invention and the polyurethane foam obtained by foaming the composition are not particularly limited in their applications, and they can be used to fill cavities in structures such as buildings, furniture, automobiles, trains, ships, etc., or to be sprayed onto such structures. Of these, the application of spraying onto structures, i.e., use as a flame-retardant urethane resin composition for 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, causing them to collide and mix at the tip of the spray gun, and turning the mixed liquid into a mist using air pressure. The volume ratio of the polyisocyanate composition to the polyol composition in the mixed liquid (polyisocyanate composition/polyol composition) is not particularly limited, but is usually 0.8 to 1.2, and more usually 0.9 to 1.1.
Spraying devices and spray guns are well known and commercially available products can be used. The temperature and pressure of the concentrate can be set in the same manner as for general urethane foam spraying.

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

[Materials used]
Details of each component used in each example and comparative example are as follows.
<Polyol Composition>
(Polyol Compound)
p-Phthalic acid polyester polyol 1 (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RFK-505, hydroxyl value = 250 mg KOH/g)
p-Phthalic acid polyester polyol 2 (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RLK-087, hydroxyl value = 200 mg KOH/g)

(Phosphate ester (liquid flame retardant))
Tris(β-chloropropyl)phosphate (manufactured by Daihachi Chemical Co., Ltd., product name: TMCPP)
(Foam stabilizer)
Silicone foam stabilizer ("SH-193" manufactured by Toray Dow Corning Co., Ltd.)

<Catalyst>
Trimerization catalyst 1: metal catalyst, potassium 2-ethylhexanoate (manufactured by Evonik Japan, product name: DABCO (registered trademark) K-15), concentration 70 to 80% by mass
Trimerization catalyst 2: quaternary ammonium salt, 2,2-dimethylpropanoic acid tetramethylammonium salt (manufactured by Evonik Japan, product name: DABCO (registered trademark) TMR-7), concentration 45 to 55% by mass
Foaming catalyst: N,N,N',N'-tetramethylguanidine (manufactured by Evonik Japan, product name "POLYCAT 201", a mixture of water and ethylene glycol (60% by mass of N,N,N',N'-tetramethylguanidine, 32% by mass of ethylene glycol, 8% by mass of water)
Urethane catalyst: transition metal salt, bismuth 2-ethylhexanoate (manufactured by Nitto Kasei Co., Ltd., product name: BI28), concentration 81 to 90% by mass

(filler)
Filler: Red phosphorus (Rinkagaku Kogyo, product name: Novaexcel 140), solid flame retardant Filler: Wollastonite (SiO2/CaO) (Kinseimatec, product name: SH-1250), solid flame retardant

(Blowing agent)
Water and HFO-1233zd (hydrofluoroolefin) (manufactured by Honeywell, product name: Solstice LBA)

<Polyisocyanate Compound>
- Polymeric MDI (manufactured by Tosoh Corporation, product name: Millionate MR-200)

The methods for measuring and evaluating the physical properties of the polyurethane foam are as follows.
[Moisture percentage]
The polyol composition was measured using a Karl Fischer moisture analyzer (manufactured by Kyoto Electronics Manufacturing Co., Ltd., product name: MKV-710).

[Cream Time (CT)]
The liquid temperatures of the polyol composition having the composition shown in Table 1 and the polyisocyanate composition comprising the polyisocyanate compound (MDI) were each adjusted to 10°C. Then, in a room at 23°C, the polyol composition and polyisocyanate composition adjusted to 10°C were poured into a 500 mL cup so that the total amount of the mixed solution was 60 g, at a mixing ratio that would result in the isocyanate index shown in the table. The mixed solution was then immediately stirred for 2 seconds at 8000 rpm using a Lab-Ispa (a high-speed disperser, Homodisper 2.5, manufactured by PRIMIX). The time when stirring began was designated the measurement start time (0 seconds), and the time (seconds) until the mixed solution changed color and the liquid level began to rise due to foaming was measured and recorded as the cream time.

[Gel time (GT)]
The liquid temperatures of the polyol composition having the composition shown in Table 1 and the polyisocyanate composition comprising the polyisocyanate compound (MDI) were each adjusted to 10°C. Then, in a room at 23°C, the polyol composition and polyisocyanate composition adjusted to 10°C were poured into a 500 mL cup so that the total amount of the mixed solution was 60 g, at a mixing ratio that would result in the isocyanate index shown in the table. The mixed solution was then immediately stirred for 2 seconds at 8000 rpm using a Lab-Ispa (a high-speed disperser, Homodisper 2.5, manufactured by PRIMIX). The time when stirring began was defined as the measurement start time (0 seconds). The time (seconds) until the foam began to form strings when a stick was pierced into the foam during foaming was measured, and this was defined as the gel time.

[Observation of the cell state of polyurethane foam]
The polyurethane foams produced in each Example and Comparative Example were visually observed and rated as "Good" if the cells were fine and there were no noticeable cell breaks, and "Poor" if the cells were rough due to cracks or other reasons.

[External contamination (bleed)]
A line was drawn on the surface of the obtained polyurethane foam with a marker (ZEBRA's "Mackie Extra Fine" oil-based black), and those that did not repel the marker ink were evaluated as "Good", and those that did repel the marker ink were evaluated as "Poor." Note that repellency of the marker ink means that a foam stabilizer or the like has bled out onto the surface of the polyurethane foam, indicating that it is likely to contaminate objects to which it is used.

[Examples 1 to 4, Comparative Examples 1 and 2]
A polyol composition obtained according to the formulation shown in Table 1 and a polyisocyanate composition comprising a polyisocyanate compound were mixed together to a total weight of 200 g and stirred at 8,000 rpm at a liquid temperature of 10°C for 2 seconds to obtain a flame-retardant urethane resin composition. The flame-retardant urethane resin composition was then sprayed into a box measuring 180 mm x 180 mm and 100 mm deep to form a polyurethane foam. The polyurethane foam thus formed was evaluated for the above-mentioned "cell state observation of polyurethane foam" and "external contamination (bleeding)."

Note that the parts by mass of each catalyst are parts by mass of the product.

Since the polyol compositions of the Examples did not contain a foam stabilizer, the resulting polyurethane foams had little bleeding on the surface and were less flammable. Furthermore, despite not containing a foam stabilizer, the cells were in good condition, had low thermal conductivity, and had excellent heat insulation properties.
On the other hand, the polyol composition of Comparative Example 1, although not containing a foam stabilizer, had a moisture content exceeding 1.8% by mass, resulting in coarse cells and poor heat insulation. The polyol composition of Comparative Example 2, although having a moisture content of 1.8% by mass or less, contained a foam stabilizer, and therefore the polyurethane foams obtained from these compositions were all highly flammable, and furthermore, a large amount of bleeding occurred on the surface.

Claims (8)

A flame-retardant urethane resin composition comprising a polyol composition and a polyisocyanate composition, the composition being used to prepare a heat insulating material by mixing the polyol composition and the polyisocyanate composition,
The polyol composition contains a polyol compound, a liquid flame retardant, a catalyst, and a blowing agent,
the polyisocyanate composition contains a polyisocyanate compound;
The flame-retardant urethane resin composition does not contain a foam stabilizer,
The liquid flame retardant is a phosphate ester-based flame retardant,
A flame-retardant urethane resin composition (excluding those containing an acrylic surface conditioner), wherein the polyol composition has a moisture content of 1.8 mass % or less. The flame-retardant urethane resin composition according to claim 1, wherein the catalyst contains a metal-based urethane catalyst. The flame-retardant urethane resin composition according to claim 1 or 2, wherein the catalyst contains a trimerization catalyst. The flame-retardant urethane resin composition according to any one of claims 1 to 3, wherein the polyol composition contains a filler. The flame-retardant urethane resin composition according to any one of claims 1 to 4, wherein the cream time of the flame-retardant urethane resin composition is 10 seconds or less. The flame-retardant urethane resin composition according to any one of claims 1 to 5, wherein the isocyanate index of the flame-retardant urethane resin composition is 150 to 700. The flame-retardant urethane resin composition according to any one of claims 1 to 6, which is intended for spray application. A polyurethane foam formed by foaming the flame-retardant urethane resin composition according to any one of claims 1 to 7.