JP7674872B2 - Polyol composition, flame-retardant rigid polyurethane foam and method for producing same - Google Patents

Description

The present invention relates to a polyol composition used in the production of a flame-retardant rigid polyurethane foam, as well as a flame-retardant rigid polyurethane foam using the same and a method for producing the same.

Rigid polyurethane foam insulation is widely used in buildings due to its excellent insulating performance and easy application. However, fires are often caused by sparks from welding and cutting during construction, renovation, and demolition work, which can lead to the spread of fire in the insulation.
In order to reduce such fire accidents, efforts are being made to make the rigid polyurethane foam itself flame retardant, and consideration is being given to adding a flame retardant to the raw material liquid of the rigid polyurethane foam to improve the flame retardancy.

Red phosphorus, a powder flame retardant, is known as a flame retardant. Red phosphorus is a powder with a high specific gravity and is prone to settling in the raw material liquid of rigid polyurethane foam, so an anti-settling agent is used in combination with it from the viewpoints of storage stability and on-site workability.
As an agent for preventing sedimentation of red phosphorus, for example, Patent Document 1 describes the incorporation of metal oxide fine particles, and Patent Document 2 describes the addition of carbon black, finely divided silica, hydrogenated castor oil wax, fatty acid amide wax, organic clay, and the like.

JP 2020-63396 A JP 2012-219127 A

Red phosphorus is a substance that has flammable properties, and so great care must be taken when handling it safely. In recent years, there has been progress in the development of flame retardants with superior flame retardancy to red phosphorus, and flame retardants made from various phosphorus compounds are also beginning to be used. For example, as flame retardants to be used in place of or in combination with red phosphorus, there are powder flame retardants made from phosphorus compounds such as phosphates and phosphinates. Like red phosphorus, these powder flame retardants made from phosphorus compounds are also difficult to dissolve in the polyol compounds and polyisocyanate compounds that are the raw materials for rigid polyurethane foam, and because they are powders with a high specific gravity, they must be used in combination with an anti-settling agent.

However, adding only a red phosphorus anti-settling agent as described in Patent Documents 1 and 2 to the powder flame retardant of the phosphorus compound does not necessarily suppress sedimentation well. Furthermore, once the sediment aggregates and solidifies (caking), it may be difficult to uniformly redisperse the settled and aggregated powder by stirring the raw material liquid of the rigid polyurethane foam during construction at the site. As a result, a rigid polyurethane foam with good flame retardancy may not be obtained.

Therefore, when using powder flame retardants other than red phosphorus, it is required that the settling and aggregation of the powder (solid) in the raw material liquid of the polyol composition or rigid polyurethane foam is suppressed, and that the handling properties are excellent in order to obtain a uniform raw material liquid.

The present invention has been made to solve the above technical problems, and aims to provide a polyol composition containing a powder flame retardant other than red phosphorus and a raw material liquid for a flame-retardant rigid polyurethane foam, which suppresses powder settling and aggregation and can produce a rigid polyurethane foam with excellent flame retardancy, as well as a flame-retardant rigid polyurethane foam and a method for producing the same using the same.

The present invention is based on the discovery that by using an anti-settling agent and a dispersant in a polyol composition containing a powder flame retardant other than red phosphorus, the settling and aggregation of the powder can be effectively suppressed, and a rigid polyurethane foam with excellent flame retardancy can be obtained.

That is, the present invention provides the following [1] to [11].
[1] A polyol composition for use in the production of a flame-retardant rigid polyurethane foam, comprising a polyol compound, a powder flame retardant other than red phosphorus, an anti-settling agent, and a dispersant.
[2] The polyol composition according to the above [1], wherein the powder flame retardant comprises at least one selected from the group consisting of phosphates and phosphinates.
[3] The polyol composition according to the above [1] or [2], wherein the anti-settling agent comprises one or more selected from organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax.
[4] The polyol composition according to any one of the above [1] to [3], wherein the dispersant comprises at least one selected from an organic ammonium salt, a phosphoric acid ester, and a phosphoric acid ester salt.
[5] The polyol composition according to any one of the above [1] to [4], wherein the polyol compound comprises a Mannich polyol.
[6] The polyol composition according to any one of the above [1] to [5], further comprising a blowing agent.
[7] The polyol composition according to the above [6], wherein the blowing agent comprises at least one selected from hydrofluoroolefins and hydrochlorofluoroolefins.
[8] The polyol composition according to any one of the above [1] to [7], which contains a catalyst.
[9] The polyol composition according to any one of the above [1] to [8], further comprising a foam stabilizer.

[10] A flame-retardant rigid polyurethane foam, which is a reaction product of the polyol composition according to any one of [1] to [9] above and a polyisocyanate compound.
[11] A method for producing a flame-retardant rigid polyurethane foam, comprising mixing the polyol composition according to any one of [1] to [9] above with a polyisocyanate compound, and foaming and curing the mixture to obtain a flame-retardant rigid polyurethane foam.

According to the present invention, in a polyol composition containing a powder flame retardant other than red phosphorus and a raw material liquid for a flame-retardant rigid polyurethane foam, settling and aggregation of the powder are suppressed, and a polyol composition with excellent handleability can be provided.
Furthermore, by using the polyol composition, a rigid polyurethane foam having excellent flame retardancy can be obtained.

The polyol composition of the present invention, as well as the flame-retardant rigid polyurethane foam using the same and the method for producing the same, are described in detail below.

[Polyol composition]
The polyol composition of the present invention is a polyol composition used for producing a flame-retardant rigid polyurethane foam, and contains a polyol compound, a powdery flame retardant other than red phosphorus, an anti-settling agent, and a dispersant.
By using such a polyol composition, it is possible to effectively suppress the settling or aggregation of powder in the raw material liquid of a flame-retardant rigid polyurethane foam containing a powder flame retardant other than red phosphorus. This can reduce the workload for uniformly mixing the polyol composition and the raw material liquid of a flame-retardant rigid polyurethane foam during the production of the flame-retardant rigid polyurethane foam, and can also improve the uniform dispersion of the powder in the raw material liquid. In addition, the flame-retardant rigid polyurethane foam produced using the raw material liquid can be obtained as one having excellent flame retardancy due to the powder flame retardant.

<Polyol Compound>
A polyol compound is a main component of raw material compounds for flame-retardant rigid polyurethane foams. A polyol compound is an alcohol compound having two or more hydroxyl groups, and produces a polyurethane resin by a polyaddition reaction with a polyisocyanate compound.

From the viewpoint of excellent flame retardancy, the polyol compound used in the production of the flame-retardant rigid polyurethane foam preferably contains mainly a polyester polyol, and more preferably contains an aromatic polyester polyol.
Polyester polyols can impart superior flame retardancy compared to polypropylene glycols and the like that are commonly used as raw materials for polyurethane foams.

From the viewpoint of obtaining a flame-retardant rigid polyurethane foam having excellent flame retardancy, the polyester polyol preferably has a hydroxyl value of 100 to 900 mgKOH/g, more preferably 150 to 800 mgKOH/g, and even more preferably 180 to 700 mgKOH/g.

The polyol compound more preferably includes a Mannich polyol, and further preferably includes an aromatic polyester polyol and a Mannich polyol.
The inhibition of powder aggregation in the raw material liquid of the polyol composition and the flame-retardant rigid polyurethane foam is mainly due to the action of the dispersant, but by including a Mannich polyol as a polyol compound together with the dispersant, the aggregation of the powder can be inhibited even more effectively.

The polyol compound may contain, in addition to polyester polyols and Mannich polyols, for example, aromatic polyether polyols other than Mannich polyols. From the viewpoint of obtaining a rigid polyurethane foam with excellent flame retardancy, it is preferable that the polyol compound contains as few aliphatic polyols as possible. The total content of aromatic polyols in 100 parts by mass of the polyol compound is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 100 parts by mass.

The total content of the polyol compounds in the polyol composition is preferably 10 to 60 parts by mass, more preferably 20 to 55 parts by mass, and even more preferably 25 to 50 parts by mass, per 100 parts by mass of the polyol composition, from the viewpoint of obtaining a flame-retardant rigid polyurethane foam having excellent flame retardancy and appropriate hardness.

(Polyester polyol)
From the viewpoint of obtaining a flame-retardant rigid polyurethane foam having excellent flame retardancy and appropriate hardness, the polyester polyol is preferably an aromatic polyester polyol, for example, a compound obtained by polycondensation of an aromatic polycarboxylic acid and a polyhydric alcohol, etc. The aromatic polyester polyol may be used alone or in combination of two or more kinds.
Specific examples of aromatic polyvalent carboxylic acids include phthalic acid, terephthalic acid, orthophthalic acid, isophthalic acid, trimellitic acid, hemimellitic acid, and pyromellitic acid.
Specific examples of polyhydric alcohols include ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A.
Examples of aromatic polyester polyols include those obtained by transesterifying polyalkylene terephthalates such as polyethylene terephthalate and polybutylene terephthalate with polyhydric alcohols.

From the viewpoint of obtaining a rigid polyurethane foam having excellent flame retardancy, it is preferable that the proportion of aromatic polyester polyol is the largest in the polyol compound, and the content of aromatic polyester polyol in the polyol compound is preferably 50 parts by mass or more, more preferably 55 to 98 parts by mass, and even more preferably 60 to 95 parts by mass, per 100 parts by mass of the polyol compound.

(Mannich polyol)
The Mannich polyol in the present invention refers to an aromatic polyether polyol obtained by addition polymerization of an alkylene oxide to an aromatic polyol, which is a product (Mannich condensation product) obtained by the Mannich reaction of a phenol compound, an aldehyde compound, and an amine compound. The Mannich polyol may be used alone or in combination of two or more kinds.
As the phenol compound, for example, phenol; alkylphenols such as cresol and nonylphenol, etc. are generally used.
As the aldehyde compound, for example, formaldehyde, acetaldehyde, etc. are generally used.
Examples of the amine compound include aliphatic primary or secondary monoamines. Generally used are alkanolamines such as monoethanolamine, diethanolamine, and 1-amino-2-propanol; and alkylamines such as methylamine and diethylamine.
As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, etc. are generally used.
Specifically, the Mannich polyol can be produced by the production method described in WO 2010/147091 and the like.

When the polyol compound contains a Mannich polyol, the content thereof is preferably 1 to 25 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass, per 100 parts by mass of the polyol compound, from the viewpoints of suppressing aggregation of powder in the polyol composition and obtaining a rigid polyurethane foam having excellent flame retardancy.
From the same viewpoint, the ratio of the Mannich polyol content to the aromatic polyester polyol content is preferably 0.02 to 1.00, more preferably 0.05 to 0.80, and even more preferably 0.08 to 0.50.

<Powder flame retardant>
The powder flame retardant used in the polyol composition of the present invention is a powder flame retardant other than red phosphorus. The polyol composition of the present invention uses a powder flame retardant that is safer to handle than red phosphorus, a conventional powder flame retardant, and can impart excellent flame retardancy to a rigid polyurethane foam, thereby suppressing settling and aggregation of the powder in the raw material liquid of the polyol composition and the flame-retardant rigid polyurethane foam.
Here, the powder flame retardant refers to a flame retardant which is solid at 15° C. and 1 atmospheric pressure and which exists as a powder (solid) without dissolving in the polyol composition.

The powder flame retardant preferably contains one or more selected from phosphates and phosphinates. The phosphates and phosphinates may be used alone or in combination of two or more.

The phosphate may be an inorganic phosphate or an organic phosphate, and examples thereof include various phosphates of one or more metals or compounds selected from metals of Groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines.
Examples of various phosphoric acids include orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and the like. Also, organic phosphoric acids such as alkyl phosphoric acids may be used.
Specific examples of metals include lithium, sodium, calcium, barium, iron, aluminum, titanium, zinc, etc. Specific examples of aliphatic amines include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine, etc. Specific examples of aromatic amines include pyridine, triazine, melamine, etc.

The phosphinate may be an inorganic phosphinate or an organic phosphinate, and examples thereof include various phosphinates of one or more metals or compounds selected from metals of Groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines.
The various phosphinic acids may be phosphinic acids or organic phosphinic acids such as alkylphosphinic acids.
Specific examples of metals, aliphatic amines and aromatic amines include those similar to those mentioned above for the phosphates.

The phosphates and phosphinates may be subjected to a surface treatment such as a silane coupling agent treatment or a melamine coating treatment.
From the viewpoint of further improving flame retardancy, the powder flame retardant may contain, in addition to the phosphate and the phosphinate, a component that can act as a flame retardant assistant, and it is preferable that the powder flame retardant contains, for example, a nitrogen-containing compound such as melamine phthalate, melamine cyanurate, or benzoguanamine.
When the powder flame retardant contains a nitrogen-containing compound, the content thereof is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the total of the phosphate and the phosphinate.

From the viewpoint of obtaining a rigid polyurethane foam with excellent flame retardancy, the powder flame retardant is preferably present in an amount of 10 to 55 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the polyol composition.

<Liquid flame retardant>
In addition to the powder flame retardant, the polyol composition preferably contains a liquid flame retardant.
Here, the liquid flame retardant refers to a flame retardant that is liquid at 15° C. and 1 atmospheric pressure or that dissolves in the polyol composition.
The liquid flame retardant preferably contains a phosphoric acid ester from the viewpoint of the effect of suppressing initial carbonization during heating or combustion of the rigid polyurethane foam.

The phosphate ester may be a monophosphate ester or a condensed phosphate ester.
Examples of monophosphate esters include trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, and also tris(β-chloropropyl) phosphate, which is a halogen-containing phosphate ester.
Examples of the condensed phosphate ester include trialkyl polyphosphate, resorcinol bisphenyl phosphate, and bisphenol A bisdiphenyl phosphate.

When a liquid flame retardant is contained in the polyol composition, the content thereof is preferably 1 to 50 parts by mass, more preferably 2 to 45 parts by mass, and even more preferably 5 to 40 parts by mass, per 100 parts by mass of the polyol composition, from the viewpoint of the effect of suppressing initial carbonization during heating or combustion of the rigid polyurethane foam.

<Anti-settling agent>
The anti-settling agent has the role of suppressing the settling of powder particles having a large specific gravity, such as a powder flame retardant, in the polyol composition, and is also called a thixotropic agent.
The anti-settling agent acts to suppress the settling of the powder by thickening the polyol composition in a stationary state through the formation of hydrogen bonds in the polyol composition, the formation of crosslinked structures via the adsorption groups of the powder particles, the entanglement of polymer chains, etc. The hydrogen bonds, crosslinked structures, and entanglement of polymer chains are easily released when shear such as stirring is applied, so that the viscosity of the polyol composition and the raw material liquid of the flame-retardant rigid polyurethane foam is not too high during the production of the flame-retardant rigid polyurethane foam, and the workload for uniform mixing is not excessively high.

The anti-settling agent used in the present invention preferably includes at least one selected from organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax. These may be used alone or in combination of two or more.
These anti-settling agents are suitable because they can effectively inhibit the settling of powder even when contained in a small amount in the polyol composition.
The content of the anti-settling agent in the polyol composition is preferably 0.01 to 5.00 parts by mass, more preferably 0.02 to 2.00 parts by mass, and even more preferably 0.05 to 1.00 parts by mass, per 100 parts by mass of the polyol composition.

Carbon black, silica powder, and the like are known as anti-settling agents for red phosphorus. Although these have a thickening effect in polyol compositions using the powder flame retardant, they tend to cause the powder to easily aggregate. For this reason, it is preferable to use one or more of organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax as the anti-settling agent in the present invention.

Organic bentonite is an organically modified clay that is modified by ion-exchanging the cations between the crystal layers of the clay mineral montmorillonite with quaternary ammonium ions. Organic bentonite has low hydrophilicity and is difficult to disperse in water, but has high affinity with polyol compounds and exerts an excellent sedimentation suppressing effect on the powder in the polyol composition.
Fatty acid amide wax has a long-chain fatty acid group and an amide group in the molecule, and is thermally and chemically stable. Hydrogenated castor oil wax is a triglyceride of saturated fatty acid obtained by hydrogenating refined castor oil. Hydrogenated castor oil wax and fatty acid amide wax are wax-based anti-settling agents, and both have excellent anti-settling effect on powder in the polyol composition.

<Dispersant>
The dispersant plays a role in preventing the powder (solid) particles in the polyol composition from agglomerating, caking, or gelling.
In the polyol composition containing the powder flame retardant of the present invention, if only an anti-settling agent as described above is used, it is difficult to uniformly disperse the powder in the raw material liquids of the polyol composition and the flame-retardant rigid polyurethane foam when stirring or the like is performed to mix them during the production of the flame-retardant rigid polyurethane foam, and a rigid polyurethane foam having excellent flame retardancy due to the powder flame retardant cannot be obtained.
The polyol composition of the present invention, when used in combination with an anti-settling agent and a dispersant, can effectively suppress the settling and aggregation of powder in the raw material liquid for a flame-retardant rigid polyurethane foam, and by using such a raw material liquid, a rigid polyurethane foam having excellent flame retardancy can be obtained.

In the polyol composition, the dispersant adsorbs to the surface of the powder particles, and generates distance between the powder particles due to electrical repulsion or steric hindrance, thereby suppressing the aggregation of the powder. By using a dispersant, even if the powder in the polyol composition has once settled, the powder can be easily dispersed by re-stirring the polyol composition, etc.

The dispersant used in the present invention preferably contains at least one selected from organic ammonium salts, phosphoric acid esters, and phosphoric acid ester salts. Examples of the organic ammonium salts include alkyl ammonium salts and alkylol ammonium salts. These may be used alone or in combination of two or more.
These dispersants are suitable because even if their content in the polyol composition is small, they can effectively suppress the aggregation of powder when used in combination with an anti-settling agent.
The content of the dispersant in the polyol composition is preferably 0.05 to 5.00 parts by mass, more preferably 0.10 to 2.00 parts by mass, and even more preferably 0.15 to 1.00 parts by mass, per 100 parts by mass of the polyol composition.

The dispersant is preferably a polymer-type dispersant having a main chain of polyester, polyether, polycarboxylic acid, or the like, and has a group that is easily adsorbed to the powder flame retardant. The organic ammonium salt has a basic group based on a quaternary ammonium group, and the phosphate ester and phosphate ester salt have a phosphate ester group.

<Other ingredients>
As the raw materials for producing a flame-retardant rigid polyurethane foam, in addition to the main raw materials, that is, a polyol compound, a flame retardant, and a polyisocyanate compound, it is preferable to compound a blowing agent, a catalyst, a foam stabilizer, etc. These components may be added separately from the polyol composition when producing the flame-retardant rigid polyurethane foam, but from the viewpoint of reducing the workload when applying the flame-retardant rigid polyurethane foam, it is preferable that they are contained in the polyol composition.
Furthermore, the polyol composition may contain additives such as a solvent, a filler, a colorant, and an antioxidant, if necessary, within the range that does not impair the effects of the present invention.

(Foaming Agent)
The foaming agent has the effect of generating gas by heat generated during a resinification reaction in which a polyol compound reacts with a polyisocyanate compound to form a urethane bond, thereby foaming the polyurethane resin.
Examples of the blowing agent include hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), hydrofluorocarbons (HFCs), water, and the like. These may be used alone or in combination of two or more. Of these, HFOs and HCFOs are blowing agents whose demand is expected to increase in the future in place of HFCs from the viewpoint of preventing global warming, and it is preferable to use these. Specific examples include trans-1,3,3,3-tetrafluoropropene (trans-HFO-1234ze), 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz), trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), and the like.

The isocyanate group of the polyisocyanate compound reacts with water to form a urea bond, and also undergoes a foaming reaction that generates carbon dioxide gas. Water induces foaming in the early stages of the reaction to produce rigid polyurethane foam, and water may be included as a blowing agent to reduce the density of the rigid polyurethane foam produced.

The amount of the foaming agent to be added is preferably 5.0 to 40.0 parts by mass, more preferably 10.0 to 30.0 parts by mass, and even more preferably 12.0 to 25.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound, from the viewpoint of foaming the polyurethane resin appropriately.
In addition, when water is contained as a blowing agent, from the viewpoint of suppressing hydrolysis of the polyol compound, the content of water is preferably less than that of the blowing agents other than water, and is preferably 20.0 parts by mass or less, more preferably 15.0 parts by mass or less, and even more preferably 10.0 parts by mass or less, per 100 parts by mass of the total of the blowing agents other than water.

(catalyst)
In the reaction for producing rigid polyurethane foam, a tertiary amine catalyst, a metal-based urethane catalyst, etc. are preferably used from the viewpoint of promoting the resinification reaction and the foaming reaction. In addition, a nurate catalyst (trimerization catalyst) is preferably used from the viewpoint of improving flame retardancy by partial nurate. As these various catalysts, catalysts known in the production of rigid polyurethane foam can be used. These catalysts may be used alone or in combination of two or more.

Examples of the tertiary amine catalyst include dimethylethanolamine, triethylenediamine, methyldicyclohexylamine, dimethylcyclohexylamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, diethylmethylbenzenediamine, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1,4-diazabicyclo[2.2.2]octane, etc. These may be used alone or in combination of two or more.
The amount of the tertiary amine catalyst to be added is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 8.0 parts by mass, and even more preferably 0.5 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound, from the viewpoint of appropriately promoting the resinification reaction and the foaming reaction of the rigid polyurethane foam.

Examples of metal-based urethanization catalysts include dibutyltin diacetate, dibutyltin dilaurate, aluminum acetylacetone, zirconium acetylacetone, bismuth 2-ethylhexylate, bismuth neodecanoate, lead naphthenate, lead octylate, zinc naphthenate, zinc octylate, etc. These may be used alone or in combination of two or more.
The amount of the metal-based urethanization catalyst to be added is preferably 0.01 to 2.0 parts by mass, more preferably 0.02 to 1.0 part by mass, and even more preferably 0.05 to 0.5 part by mass, per 100 parts by mass of the polyisocyanate compound, from the viewpoint of appropriately promoting the resinification reaction and the foaming reaction of the rigid polyurethane foam.

Examples of the nurate catalyst 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 salts of carboxylates such as potassium acetate and potassium 2-ethylhexylate; tertiary ammonium salts such as trimethylammonium salts, triethylammonium salts, and triphenylammonium salts; and quaternary ammonium salts such as tetramethylammonium salts, tetraethylammonium, and tetraphenylammonium salts. These may be used alone or in combination of two or more.
The amount of the nurate catalyst to be added is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 8.0 parts by mass, and even more preferably 0.5 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound, from the viewpoint of appropriately promoting the nurate reaction of isocyanate.

(Foam stabilizer)
The foam stabilizer is added from the viewpoint of obtaining a homogeneous flame-retardant rigid polyurethane foam, and any foam stabilizer known in the art for producing rigid polyurethane foams can be used. In general, silicone-based foam stabilizers are preferably used, such as siloxane-polyalkylene oxide copolymers.
The amount of the foam stabilizer to be added is appropriately set depending on the type of polyurethane resin to be produced, but is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 8.0 parts by mass, and even more preferably 0.5 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound.

<Method of producing polyol composition>
The method for producing the polyol composition of the present invention is not particularly limited, and the polyol composition can be produced by blending the above-mentioned components contained in the polyol composition and stirring and mixing them using a known stirring device such as a homodisper or a planetary stirrer.

[Flame-retardant rigid polyurethane foam]
The flame-retardant rigid polyurethane foam of the present invention is a reaction product of the polyol composition and a polyisocyanate compound.
When a polyol composition in which the powder is not sufficiently uniformly dispersed is used, it is difficult to obtain a homogeneous rigid polyurethane foam having excellent flame retardancy overall.
In contrast, according to the polyol composition of the present invention, as described above, even if the polyol composition contains a powder flame retardant having a large specific gravity, the settling and aggregation of the powder in the raw material liquid of the polyol composition and the flame-retardant rigid polyurethane foam can be effectively suppressed. Therefore, when producing a flame-retardant rigid polyurethane foam, the workload of stirring and the like for uniformly mixing the polyol composition and the raw material liquid of the flame-retardant rigid polyurethane foam can be reduced, and the uniform dispersion of the powder in the raw material liquid can be improved. In addition, the produced flame-retardant rigid polyurethane foam is obtained as one having excellent flame retardancy due to the powder flame retardant.

<Polyisocyanate Compound>
The polyisocyanate compound is an isocyanate compound having two or more isocyanate groups, and produces a polyurethane resin by a polyaddition reaction with a polyol compound.
The polyisocyanate compound may be any of aromatic polyisocyanates and aliphatic polyisocyanates, and these may be used alone or in combination of two or more kinds.

Examples of aromatic polyisocyanates include diphenylether-2,4'-diisocyanate, diphenylether-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 4,6-dimethyl-1,3-phenylene diisocyanate, monomeric MDI such as 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymethylene polyphenyl polyisocyanate (crude MDI or polymeric MDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate, and m-xylylene diisocyanate.
The aliphatic polyisocyanate may be either an acyclic or an alicyclic polyisocyanate, and examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.
Among these, from the viewpoints of reactivity and the flame retardancy of the produced rigid polyurethane foam, preferably, monomeric MDI such as 2,2'-MDI, 2,4'-MDI, 4,4'-MDI, crude MDI or polymeric MDI is used, and further, from the viewpoints of availability, cost and the like, crude MDI or polymeric MDI is more preferably used.

The amount of polyisocyanate compound in the raw material liquid for flame-retardant rigid polyurethane foam is appropriately set depending on the type of polyisocyanate compound, but from the viewpoints of sufficient reactivity with the polyol compound and ease of handling during mixing of the raw material liquid, the amount is preferably 50 to 200 parts by mass, more preferably 70 to 150 parts by mass, and even more preferably 80 to 120 parts by mass per 100 parts by mass of the polyol composition.

<Method for producing flame-retardant rigid polyurethane foam>
In the method for producing a flame-retardant rigid polyurethane foam of the present invention, the polyol composition and a polyisocyanate compound are mixed, foamed and cured to obtain a flame-retardant rigid polyurethane foam.
The foaming and curing method for obtaining the flame-retardant rigid polyurethane foam is not particularly limited, and for example, known methods such as various moldings such as slab molding, mold molding, laminate molding, injection molding, spray foaming, etc. can be applied. In these various foaming and curing methods, a raw material liquid for the flame-retardant rigid polyurethane foam, which is a mixture of the polyol composition and the polyisocyanate compound, is foamed and cured, whereby a homogeneous rigid polyurethane foam having excellent flame retardancy overall can be produced.

As described above, the polyol composition suppresses settling and aggregation of the powder contained therein, so when the polyol composition is mixed with a polyisocyanate compound, the powder can be easily and uniformly dispersed without the need for large shear forces, for example, by using a general stirrer equipped with stirring blades. Therefore, by using the polyol composition, the raw material liquid can be mixed with little work, and the production of rigid polyurethane foam with excellent flame retardancy can be made more efficient.

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

[Preparation of polyol composition]
Details of each raw material used in the preparation of the polyol compositions in the following Examples and Comparative Examples are shown below.
<Polyol Compound>
Polyester polyol (RFK-556): Terephthalic acid-based polyester polyol; "Maximol (registered trademark) RFK-556", manufactured by Kawasaki Chemical Industries, Ltd.; hydroxyl value 224 mg KOH/g
Mannich polyol (NB-622): "Exenol (registered trademark) NB-622", manufactured by AGC Inc., hydroxyl value 500 mg KOH/g
<Powder flame retardant>
Phosphinate (CM-6R): "Furan CM-6R" manufactured by Yamato Chemical Industry Co., Ltd.; nitrogen-containing compound Phosphate (R1910-4): "Non-Nen (registered trademark) R1910-4" manufactured by Marubishi Yuka Kogyo Co., Ltd.; nitrogen-containing compound Red phosphorus: "Nova Excel (registered trademark) 140" manufactured by Rinkagaku Kogyo Co., Ltd. <Liquid flame retardant>
Halogen-containing phosphate ester (TMCPP): Tris(β-chloropropyl)phosphate; "TMCPP", manufactured by Daihachi Chemical Industry Co., Ltd. <Anti-settling agent>
Organic bentonite (BENTONE 38): "BENTONE (registered trademark) 38", manufactured by Elementis Specialties, Inc., powder Fatty acid amide wax (PFA-131): "DISPARLON PFA-131", manufactured by Kusumoto Chemicals Co., Ltd., active ingredient 10% by mass
Hydrogenated castor oil wax (SN Thickener 4040); "SN Thickener 4040", manufactured by San Nopco Ltd. <Dispersant>
Organic ammonium salt (BYK-2155): "DISPERBYK (registered trademark; hereinafter the same)-2155", BYK Japan Co., Ltd.; block copolymer having a basic group. Alkylol ammonium salt (BYK-180): "DISPERBYK-180", BYK Japan Co., Ltd.; alkylol ammonium salt of copolymer containing an acid group. Phosphate ester (BYK-111): "DISPERBYK-111", BYK Japan Co., Ltd.; phosphoric acid ester having phosphoric acid groups at both ends of the copolymer. Phosphate ester salt (BYK-145): "DISPERBYK-145", BYK Japan Co., Ltd.; phosphoric acid ester salt of copolymer. <Foaming agent>
HCFO (LBA): trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd); "Solstice (registered trademark) LBA", manufactured by Honeywell International, Inc. <catalyst>
Tertiary amine catalyst (KL-120): 1-isobutyl-2-methylimidazole; "Kao Raiser (registered trademark) No. 120" manufactured by Kao Corporation. Metal-based urethane catalyst (DINP17): lead octoate; "Nikka Octix (registered trademark) Lead 17% DINP" manufactured by Nippon Kagaku Sangyo Co., Ltd.; Pb content 17% by mass.
Nurate catalyst (U-18X); triethylmethylammonium 2-ethylhexane salt; "U-CAT 18X", manufactured by San-Apro Co., Ltd. <Foam stabilizer>
L-6100: Silicone foam stabilizer; "Niax (registered trademark) silicone L-6100", manufactured by Momentive Performance Materials, Inc.

Example 1
In a 500 mL plastic bottle, 28.04 parts by mass of polyester polyol RFK-556 as a polyol compound, 1.26 parts by mass of KL-120, 0.14 parts by mass of DINP17, and 3.78 parts by mass of U-18X as catalysts, 20.16 parts by mass of liquid flame retardant TMCPP, and 1.4 parts by mass of foam stabilizer L-6100 were placed, and stirred for 20 seconds at 3000 rpm with an electric drill equipped with a cage-type attachment (hereinafter, the same stirring method is used).
To this, 30.0 parts by mass of a powder flame retardant CM-6R, 0.76 parts by mass of an anti-settling agent BENTONE 38, and 0.46 parts by mass of a dispersant BYK-2155 were added and stirred for 20 seconds, and then 14.0 parts by mass of a foaming agent (HCFO) LBA was added and stirred for a further 20 seconds, and the mixture was kept warm in a thermostatic water bath at 20° C. to prepare a polyol composition.

(Examples 2 to 15, Comparative Examples 1 to 11)
Polyol compositions were prepared in the same manner as in Example 1 using the raw material blend compositions shown in Table 1 or Table 2 below.

[Production of Rigid Polyurethane Foam]
100 parts by mass of each of the polyol compositions prepared in the above Examples and Comparative Examples were stirred at 15°C, placed in a 1 L descup together with 90 parts by mass of polymethylene polyphenyl polyisocyanate (Polymeric MDI: "Millionate (registered trademark) MR-200", manufactured by Tosoh Corporation) as a polyisocyanate compound, and mixed and foamed for 5 seconds. After leaving to stand for 30 minutes, the cured product was removed from the descup to obtain a rigid polyurethane foam.

[evaluation]
The polyol compositions prepared in the above Examples and Comparative Examples and the rigid polyurethane foams produced using the same were evaluated for the following items. The evaluation results are shown in Tables 1 and 2 below.

<Sedimentation>
A 50 mL vial containing 30 g of the polyol composition was left to stand at room temperature (25° C.) By visual observation, the height position (based on the liquid level) of the upper surface of the powder (solid) sediment after one day was measured.
These measured values were evaluated based on the following evaluation criteria.
(Evaluation Criteria)
AA: The height position of the upper surface of the sediment is less than 1 mm from the liquid surface. A: The height position of the upper surface of the sediment is 1 mm or more and less than 3 mm from the liquid surface. B: The height position of the upper surface of the sediment is 3 mm or more and less than 5 mm from the liquid surface. C: The height position of the upper surface of the sediment is 5 mm or more from the liquid surface. In the case of evaluation AA, it can be considered that almost no sedimentation has progressed. In the cases of evaluation A or B, it can be said that the sedimentation has progressed slightly, but has been well suppressed. In the case of evaluation C, the sedimentation has progressed significantly, and the polyol composition was judged to be unsuitable for practical use.

<Cohesiveness>
The state of sediment in the above evaluation of <Sedimentation property> was visually observed and evaluated based on the following evaluation criteria.
(Evaluation Criteria)
AA: When the vial was turned on its side, the sediment flowed, but when it was stood upright again, it returned to its original state within 5 minutes.
A: When the vial is turned on its side, the sediment flows, and when it is turned upright again, it gradually returns to its original state. Even after leaving it to stand for 5 minutes, the sediment does not completely return to its original state, but it does not adhere to the inner wall of the vial.
B: When the vial is turned on its side, the sediment flows, and when it is turned upright again, it gradually returns to its original state. Even after being left to stand for 5 minutes, the sediment does not return to its original state completely, and some deposits remain on the inner wall of the vial.
C: The sediment does not flow even when the vial is turned on its side.
In the case of the evaluation AA, the powder aggregation suppression effect is particularly excellent, and in the cases of the evaluations A and B, the powder aggregation is suppressed well. On the other hand, in the case of the evaluation C, a sufficient aggregation suppression effect was not obtained, and the polyol composition was judged to be unsuitable for practical use.

<Flame retardancy>
A sample of 98 mm×98 mm×thickness (height) 25 mm was cut out from the rigid polyurethane foam produced above.
In accordance with ISO 5660-1, a cone caloriemeter ("Cone Caloriemeter III", manufactured by Toyo Seiki Seisakusho Co., Ltd.; noncombustible base material: gypsum board (thickness 12.5 mm)) was used to apply a heat quantity of 50 kW/ ^m2 to the sample using a cone, and at the same time, the sample was ignited for 10 seconds using an ignition plug. The total heat generated when the sample was heated for 20 minutes was measured.
These measured values were evaluated based on the following evaluation criteria.
(Evaluation Criteria)
A: Total heat generation amount is less than 8 MJ/ ^m2 B: Total heat generation amount is 8 MJ/ ^m2 or more and less than 11 MJ/ ^m2 C: Total heat generation amount is 11 MJ/ ^m2 or more and less than ²⁰ MJ/ ^m2 D: Total heat generation amount is 20 MJ/m2 or more In the case of evaluation A, it is the highest flame retardancy, and is at a level that can be called a non-combustible material. Next, in the case of evaluation B, the flame retardancy is sufficiently high, and is at a level that can be called a quasi-non-combustible material. In the cases of evaluation C or D, it was determined that the material did not have sufficient flame retardancy.

As can be seen from the results shown in Tables 1 and 2, it was found that the polyol compositions (Examples 1 to 15) in which an anti-settling agent and a dispersant were blended with a polyol composition containing a powder flame retardant suppressed the settling and aggregation of the powder and were able to produce rigid polyurethane foams having flame retardancy equivalent to or greater than that of semi-noncombustible materials.
On the other hand, when no anti-settling agent and/or dispersant was blended (Comparative Examples 1 to 5), and when red phosphorus was used as the powder flame retardant (Comparative Examples 6 to 11), no polyol composition was obtained that showed good evaluation results in terms of the powder sedimentation inhibitory effect and aggregation inhibitory effect, and the flame retardancy of the rigid polyurethane foam.

Claims (8)

A polyol composition for use in the production of a flame-retardant rigid polyurethane foam, comprising a polyol compound, a powder flame retardant other than red phosphorus, an anti-settling agent, and a dispersant ,
The powder flame retardant contains at least one selected from a phosphate and a phosphinate,
The anti-settling agent is at least one selected from organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax;
The dispersant is at least one selected from organic ammonium salts, phosphoric acid esters, and phosphoric acid ester salts.
Polyol composition. The polyol composition of claim 1 , wherein the polyol compound comprises a Mannich-type polyol. The polyol composition according to claim 1 or 2 , further comprising a blowing agent. The polyol composition according to claim 3 , wherein the blowing agent comprises at least one selected from hydrofluoroolefins and hydrochlorofluoroolefins. The polyol composition according to any one of claims 1 to 4 , further comprising a catalyst. The polyol composition according to any one of claims 1 to 5 , further comprising a foam stabilizer. A flame-retardant rigid polyurethane foam which is a reaction product of the polyol composition according to any one of claims 1 to 6 and a polyisocyanate compound. A method for producing a flame-retardant rigid polyurethane foam, comprising mixing the polyol composition according to any one of claims 1 to 6 with a polyisocyanate compound, and foaming and curing the mixture to obtain a flame-retardant rigid polyurethane foam.