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

Abstract

To provide a flame-retardant hard polyurethane foam that has high flame retardancy and can suppress the occurrence of voids and cracks in a carbonized layer during combustion and a method for producing the same, and a polyol composition for use in its production.SOLUTION: A polyol composition is mixed with a polyisocyanate compound and the mixture is foamed and cured, resulting in a flame-retardant hard polyurethane foam, wherein the polyol composition contains a polyol compound containing an aromatic polyester polyol, a flame retardant containing a predetermined phosphinic acid metal salt and / or phosphoric acid metal salt, and boehmite.SELECTED DRAWING: None

Description

[Technical field]

[0001] 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. [Background technology]

[0002] Rigid polyurethane foams have excellent heat insulating properties, and are also easy to install and economical. From the viewpoints of energy conservation and improved livability, they are widely used as heat insulating materials for buildings.

[0003] On the other hand, rigid polyurethane foam is an organic polymer material and is characterized by its high combustibility. Fires caused by sparks from welding and cutting work during construction, renovation, and demolition work often occur, causing the rigid polyurethane foam to spread. As a measure to reduce such fire accidents, various methods for imparting flame retardancy to rigid polyurethane foams have been investigated.

[0004] For example, a technique is known in which red phosphorus or a phosphate ester is added as a flame retardant to a rigid polyurethane foam to make it flame retardant. However, red phosphorus is a flammable substance and requires careful handling to ensure safety. In addition, there is a limit to the extent to which red phosphorus and phosphate esters can improve the flame retardancy of rigid polyurethane foams, and there has been a demand for flame retardants that can impart better flame retardancy and make rigid polyurethane foams closer to non-flammable materials.

[0005] In response to such problems, the present inventors have investigated the use of a more effective flame retardant, for example, a flame retardant containing a phosphinic acid metal salt, which is used as a flame retardant for polyurethane resins for synthetic leather in Patent Document 1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-79375 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the rigid polyurethane foam to which the flame retardant containing the phosphinic acid metal salt described in the above Patent Document 1 is added is prone to have a plurality of air bubbles (voids) in the carbonized layer of the rigid polyurethane foam during combustion. Furthermore, cracks may occur on the surface of the carbonized layer starting from large voids with a diameter of about 5 mm or more. The occurrence of such voids and cracks tends to be more frequent when a flame retardant containing a phosphinic acid metal salt is used than when red phosphorus or the like is used.

[0008] Flame-retardant rigid polyurethane foam is required to have excellent flame retardancy, and one of the important properties required is that it maintains its heat insulating performance by maintaining the char layer when burned.

[0009] Therefore, in the rigid polyurethane foam using the flame retardant containing the phosphinic acid metal salt, it is required that the char layer formed during burning or heating of the rigid polyurethane foam is unlikely to develop voids or cracks, and that the char layer is maintained without being burned. The same can be said about the powdered flame retardant containing the phosphate metal salt.

[0010] The present invention has been made to solve the above-mentioned technical problems, and has an object to provide a flame-retardant rigid polyurethane foam that has excellent flame retardancy and can suppress the generation of voids and cracks in the carbonized layer during combustion, a method for producing the same, and a polyol composition used in the production of the same. [Means for solving the problem]

[0011] The present invention is based on the discovery that a flame-retardant rigid polyurethane foam produced using a polyol composition containing a flame retardant containing a specific metal phosphinate salt and / or a metal phosphate salt in combination with boehmite has excellent flame retardancy and is suppressed from generating voids and cracks in the carbonized layer during combustion.

[0012] That is, the present invention provides the following [1] to [9]. [1] A polyol composition used in the production of a flame-retardant rigid polyurethane foam, comprising a polyol compound, a flame retardant, and boehmite, wherein the polyol compound comprises an aromatic polyester polyol, and the flame retardant comprises one or more phosphorus compounds selected from the group consisting of a phosphinic acid metal salt represented by the following formula (1) and a phosphoric acid metal salt:

[0013] [ka]

[0014] In formula (1), M is Mg, Al, Ca, Ti or Zn, and R 1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a phenyl group, and n is 2, 3, or 4. [2] The polyol composition according to [1] above, wherein the polyol compound comprises a Mannich polyol. [3] The polyol composition according to the above [1] or [2], wherein the boehmite is contained in an amount of 5 to 150 parts by mass per 100 parts by mass of the total solid content of the flame retardant. [4] The polyol composition according to any one of the above [1] to [3], further comprising a foaming agent. [5] The polyol composition according to the above [4], wherein the blowing agent comprises at least one of hydrofluoroolefins and hydrochlorofluoroolefins. [6] The polyol composition according to any one of the above [1] to [5], which contains a catalyst. [7] The polyol composition according to any one of [1] to [6] above, containing a foam stabilizer.

[0015] [8] A flame-retardant rigid polyurethane foam which is a reaction product of the polyol composition according to any one of [1] to [7] above and a polyisocyanate compound. [9] A method for producing a flame-retardant rigid polyurethane foam, comprising mixing the polyol composition according to any one of [1] to [7] above with a polyisocyanate compound, followed by foaming and curing to obtain the flame-retardant rigid polyurethane foam.

Effects of the Invention

[0016] By using the polyol composition of the present invention, a flame-retardant rigid polyurethane foam having excellent flame retardancy and suppressing the generation of voids and cracks in the carbonized layer during combustion can be produced. Further, according to the present invention, a production method for obtaining the flame-retardant rigid polyurethane foam is provided.

Modes for Carrying Out the Invention

[0017] Hereinafter, the polyol composition of the present invention, the flame-retardant rigid polyurethane foam using the same, and the production method thereof will be described in detail.

[0018] [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 predetermined polyol compound, a predetermined flame retardant, and boehmite. The polyol compound includes an aromatic polyester polyol, and the flame retardant includes one or more phosphorus compounds selected from the group consisting of a phosphinic acid-based metal salt represented by the following formula (1) and a phosphoric acid-based metal salt.

[0019]

Chemical Formula

[0020] In the formula (1), M is Mg, Al, Ca, Ti or Zn; R 1 represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a phenyl group; and n is 2, 3, or 4.

[0021] By using a polyol composition using a flame retardant containing a phosphinic acid metal salt and / or a phosphoric acid metal salt represented by the formula (1) in combination with boehmite, it is possible to produce a rigid polyurethane foam having excellent flame retardancy and in which the generation of voids and cracks in the carbonized layer during combustion is suppressed.

[0022] Here, the term "voids" as used in the present invention refers to a plurality of air bubbles that are generated inside the carbonized layer (carbonized layer) when the rigid polyurethane foam is burned, and does not include air bubbles that exist in parts other than the carbonized layer. The cracks referred to in the present invention refer to fissures that originate from relatively large voids (e.g., diameters of about 5 mm or more) in the outer surface of the charred layer generated during combustion of the rigid polyurethane foam. In other words, when large voids are generated, cracks are also likely to occur. The carbonized layer is formed when the rigid polyurethane foam is heated in a state where oxygen is blocked during combustion, and the rigid polyurethane foam remains as a solid with a high carbon content with strong carbon-carbon bonds without gasification. The carbonized layer formed on the surface side of the rigid polyurethane foam has the effect of blocking the intrusion of oxygen into the rigid polyurethane foam, and is considered to promote further expansion of the carbonized layer region. The formation of such a carbonized layer region is sometimes called carbonization fixation. When a sufficient carbonized layer region is formed, that is, when the carbonization fixation is good, the carbonized layer can maintain good heat insulation performance. However, when cracks occur in the carbonized layer, it becomes difficult to maintain the carbonized layer due to an increase in the burning area and an increase in the intrusion of oxygen, and it is presumed that the heat insulation performance is reduced.

[0023] <Polyol compound> The polyol compound is a raw material compound for flame-retardant rigid polyurethane foam and constitutes the polyol composition of the present invention. The 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.

[0024] As the polyol compound used in the production of the flame-retardant rigid polyurethane foam, aromatic polyols are mainly used from the viewpoint of good flame retardancy. Aromatic polyols can impart superior flame retardancy compared to aliphatic polyols used as general polyurethane foam raw materials.

[0025] From the viewpoint of obtaining a flame-retardant rigid polyurethane foam having good flame retardancy and hardness, the aromatic 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.

[0026] The polyol compound in the present invention includes an aromatic polyester polyol, and also preferably includes a Mannich polyol. By including a Mannich polyol as the polyol compound, it is possible to suppress the aggregation of powder in the raw material liquid of the flame-retardant rigid polyurethane foam, which is advantageous in terms of ease of handling when producing a flame-retardant rigid polyurethane foam using the polyol composition and a raw material liquid containing the same.

[0027] From the viewpoint of obtaining a flame-retardant rigid polyurethane foam having good flame retardancy, hardness, etc., the total content of the polyol compounds is preferably 10.0 to 60.0 parts by mass, more preferably 20.0 to 55.0 parts by mass, and even more preferably 30.0 to 50.0 parts by mass, per 100 parts by mass of the polyol composition.

[0028] (Aromatic polyester polyol) Examples of aromatic polyester polyols include compounds obtained by polycondensation of aromatic polycarboxylic acids and polyhydric alcohols. The aromatic polyester polyols may be used alone or in combination of two or more. Specific examples of aromatic polyvalent carboxylic acids include aromatic polyvalent carboxylic acids such as phthalic acid, terephthalic acid, orthophthalic acid, isophthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid, etc. 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, bisphenol A, etc. Examples of aromatic polyester polyols include those obtained by transesterifying polyalkylene terephthalates such as polyethylene terephthalate and polybutylene terephthalate with polyhydric alcohols.

[0029] From the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy, it is preferred that the aromatic polyester polyol is contained in the largest proportion among the polyol compounds. The content of the aromatic polyester polyol in the polyol compound is preferably 50.0 parts by mass or more, more preferably 60.0 to 100 parts by mass, and further preferably 70.0 to 100 parts by mass, per 100 parts by mass of the polyol compound.

[0030] (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 phenolic compound, for example, phenol; alkylphenols such as cresol and nonylphenol are generally used. As the aldehyde compound, for example, formaldehyde, acetaldehyde and the like are generally used. As the amine compound, for example, aliphatic primary or secondary monoamines can be mentioned, and alkanolamines such as monoethanolamine, diethanolamine, 1-amino-2-propanol; alkylamines such as methylamine and diethylamine are generally used. As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide and the like are generally used. Specifically, the Mannich polyol can be produced by the production method described in International Publication No. 2010 / 147091 and the like.

[0031] When the Mannich polyol is contained in the polyol compound, from the viewpoints of suppressing the aggregation of the powder in the polyol composition and obtaining a rigid polyurethane foam having good flame retardancy, in 100 parts by mass of the polyol composition, it is preferably 1.0 to 20.0 parts by mass, more preferably 2.0 to 15.0 parts by mass, and still more preferably 3.0 to 10.0 parts by mass. Also, from the same viewpoints, the mass ratio of the content of the Mannich polyol to the content of the aromatic polyester polyol is preferably 0.10 to 1.00, more preferably 0.15 to 0.90, and still more preferably 0.20 to 0.80.

[0032] The polyol compound may contain, for example, aromatic polyether polyols other than the Mannich polyols, in addition to the aromatic polyester polyols and the Mannich polyols, but from the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy, it is preferable that the polyol compound does not contain an aliphatic polyol. In addition, from the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy and maintaining a good carbonized layer state during combustion, the total content of the aromatic polyester polyols and the Mannich polyols in 100 parts by mass of the polyol compound is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, and even more preferably 100 parts by mass.

[0033] <Flame retardants> The flame retardant used in the polyol composition of the present invention contains one or more phosphorus compounds selected from the group consisting of phosphinic acid metal salts represented by the following formula (1) and phosphoric acid metal salts.

[0034] [ka]

[0035] In the formula (1), M is Mg, Al, Ca, Ti or Zn, preferably Al or Zn, more preferably Al. When M is Mg, Ca or Zn, n=2, when M is Al, n=3, and when M is Ti, n=4. R 1 represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a phenyl group, and is preferably a hydrogen atom, a methyl group, an ethyl group, or a phenyl group.

[0036] The flame retardant may contain either one of the phosphinic acid metal salt and the phosphate metal salt, or may contain both of them. From the viewpoint of the effects of the present invention, the flame retardant preferably contains the phosphinic acid metal salt.

[0037] The phosphinic acid metal salt is an inorganic phosphinic acid salt or an organic phosphinic acid salt, and is in the form of a powder. The phosphinic acid metal salt may be used alone or in combination of two or more kinds. The powdered flame retardant containing the phosphinic acid metal salt can impart superior flame retardancy to rigid polyurethane foams as compared with conventional flame retardants based on red phosphorus, phosphate esters, and the like.

[0038] The phosphate metal salt is an inorganic phosphate or an organic phosphate, and is in the form of a powder. The phosphate metal salt is preferably a phosphate metal salt. The metal atom (ion) in the phosphate metal salt is preferably a salt of the same metal atom (ion) as the phosphinic acid metal salt. The phosphate metal salt may be used alone or in combination of two or more kinds. The powdered flame retardant containing the above-mentioned phosphate metal salt can also impart excellent flame retardancy to the rigid polyurethane foam.

[0039] From the viewpoint of further improving flame retardancy, the flame retardant may contain, in addition to the phosphinic acid metal salt or the phosphate metal salt, a component that can act as a flame retardant auxiliary, and it is preferable that the flame retardant contains, for example, a nitrogen-containing compound. Examples of the nitrogen-containing compound include melamine, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine phthalate, melamine cyanurate, benzoguanamine, etc. Among these, only one type or two or more types may be contained. When the 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, relative to 100 parts by mass of the phosphinic acid metal salt.

[0040] In the present invention, as the powdered flame retardant containing the phosphinic acid metal salt and the nitrogen-containing compound, for example, commercially available products such as the "Fran CM" series manufactured by Yamato Chemical Industry Co., Ltd. can be suitably used.

[0041] In addition, from the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy, the powdery flame retardant containing the phosphinic acid metal salt and / or the phosphate metal salt is preferably present in an amount of 30 parts by mass or more, more preferably 33 to 100 parts by mass, and even more preferably 35 to 100 parts by mass, out of a total of 100 parts by mass of the flame retardant in the polyol composition. In addition, in consideration of the fact that the powdered flame retardant containing the phosphinic acid metal salt and / or the phosphate metal salt is prone to sedimentation and aggregation, the powdered flame retardant, i.e., the solid content of the flame retardant, is preferably 5.0 to 40.0 parts by mass, more preferably 8.0 to 35.0 parts by mass, and even more preferably 10.0 to 30.0 parts by mass, in 100 parts by mass of the polyol composition.

[0042] The flame retardant may contain a liquid phosphoric acid ester from the viewpoint of obtaining an effect of suppressing initial carbonization during combustion of the rigid polyurethane foam, and for example, tris(β-chloropropyl)phosphate, which is a halogen-containing phosphoric acid ester, is generally used. Tris(β-chloropropyl)phosphate is a liquid, and unlike the powder-like phosphinic acid metal salt, phosphoric acid metal salt, and red phosphorus, does not cause aggregation in the raw material liquid of the rigid polyurethane foam, but the effect of imparting flame retardancy to the rigid polyurethane foam is superior to that of the phosphinic acid metal salt and phosphoric acid metal salt. When the liquid phosphoric acid ester is contained in the flame retardant, the content thereof is preferably 70 parts by mass or less, more preferably 67 parts by mass or less, and even more preferably 65 parts by mass or less in 100 parts by mass of the flame retardant.

[0043] <Boehmite> The boehmite in the polyol composition has the chemical formula Al 2 O 3 H 2 It is a type of alumina hydrate represented by 1,0 and is a powdery particle that is insoluble in water. For example, it can be obtained as a product such as "Apilar (registered trademark) AOH" manufactured by Navaltec Corporation. The rigid polyurethane foam added with the powdery flame retardant containing the phosphinic acid metal salt and / or the phosphoric acid metal salt is likely to generate voids and cracks in the carbonized layer during combustion. However, by using boehmite in combination, the generation of voids and cracks in such a carbonized layer can be suppressed. That is, by using a polyol composition in which the powdery flame retardant containing the phosphinic acid metal salt and / or the phosphoric acid metal salt and boehmite are used in combination, a rigid polyurethane foam having excellent flame retardancy and suppressing the generation of voids and cracks in the carbonized layer during combustion can be produced.

[0044] In addition, when boehmite is blended in the polyol composition and a powdery flame retardant containing the phosphinic acid metal salt and / or the phosphoric acid metal salt is not used, it is difficult to obtain a rigid polyurethane foam having excellent flame retardancy and suppressing the generation of voids and cracks in the carbonized layer during combustion. Also, aluminum hydroxide is an oxygen-containing aluminum compound like boehmite and is known as a flame retardant filler for resins, etc. However, in rigid polyurethane foam, even when a powdery flame retardant containing the phosphinic acid metal salt and / or the phosphoric acid metal salt and aluminum hydroxide are used in combination, it is difficult to achieve good flame retardancy and suppress the generation of voids and cracks in the carbonized layer during combustion.

[0045] From the viewpoint of effectively suppressing the generation of voids and cracks in the carbonized layer during combustion of the rigid polyurethane foam and making the rigid polyurethane foam excellent in flame retardancy by using the boehmite in combination with the powdery flame retardant containing the phosphinic acid metal salt and / or the phosphoric acid metal salt, the content of the boehmite is preferably 5 to 150 parts by mass, more preferably 10 to 120 parts by mass, and still more preferably 20 to 100 parts by mass with respect to 100 parts by mass in total of the solid content in the flame retardant.

[0046] <Other components> As raw materials for producing flame-retardant rigid polyurethane foam, in addition to the main raw materials, namely polyol compounds, flame retardants, and polyisocyanate compounds, blowing agents, catalysts, foam stabilizers, etc. are also compounded. These components may be added separately from the polyol composition during the production of flame-retardant rigid polyurethane foam. However, from the perspective of reducing the workload at the production site of flame-retardant rigid polyurethane foam, it is preferable that they are compounded in the polyol composition. Furthermore, in the polyol composition, solvents, additives such as colorants and antioxidants, etc. may be included as necessary within a range that does not interfere with the effects of the present invention.

[0047] (Blowing agent) The blowing agent has the function of generating gas due to the heat generated by the exothermic resinification reaction in which the polyol compound and the polyisocyanate compound react to form a urethane bond, and foaming the polyurethane resin. Examples of the blowing agent include hydrofluoroolefin (HFO), hydrochlorofluorolefin (HCFO), hydrofluorocarbon (HFC), water, etc. These may be used alone or in combination of two or more. Among these, HFO and HCFO are blowing agents for which an increase in demand is expected in the future as a substitute for HFC from the perspective of the effect of suppressing global warming, and it is preferable to use these. Specifically, 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), etc. can be mentioned.

[0048] The isocyanate group of the polyisocyanate compound also undergoes a foaming reaction in which it reacts with water to generate a urea bond and carbon dioxide gas. Water serves as an inducement for foaming in the initial stage of the production reaction of rigid polyurethane foam, and since it can reduce the density of the produced rigid polyurethane foam, it is preferable that water is included as a blowing agent.

[0049] From the viewpoint of appropriately foaming the polyurethane resin, the amount of the foaming agent to be blended 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 in total relative to 100 parts by mass of the polyisocyanate compound. However, since there is a risk of hydrolyzing the aromatic polyester polyol, the content of water is preferably less than that of other blowing agents, and is preferably 20.0 parts by mass or less, more preferably 0.8 to 15.0 parts by mass, and even more preferably 1.0 to 10.0 parts by mass, relative to 100 parts by mass of the total of the blowing agents other than water.

[0050] (catalyst) In the reaction for producing rigid polyurethane foam, a tertiary amine catalyst is preferably used from the viewpoint of promoting the resinification reaction and the foaming reaction. In addition, a nurate catalyst can also be used from the viewpoint of improving flame retardancy by partial nurate. As these catalysts, catalysts known in the production of rigid polyurethane foam can be used. These may be used alone or in combination of two or more.

[0051] Examples of the tertiary amine catalyst include dimethylethanolamine, triethylenediamine, methyldicyclohexylamine, dimethylcyclohexylamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, diethylmethylbenzenediamine, 1,2-dimethylimidazole, and 1,4-diazabicyclo[2.2.2]octane. 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, 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.

[0052] 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 salts, and tetraphenylammonium salts. The amount of the nurate catalyst to be added is preferably 0.05 to 10.0 parts by mass, more preferably 0.1 to 8.0 parts by mass, and even more preferably 0.2 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.

[0053] (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 0.05 to 10.0 parts by mass, more preferably 0.1 to 8.0 parts by mass, and even more preferably 0.2 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound.

[0054] 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.

[0055] [Flame-retardant rigid polyurethane foam] The flame-retardant rigid polyurethane foam of the present invention is a reaction product obtained by reacting the polyol composition with a polyisocyanate compound. By using the polyol composition of the present invention in which the powdery flame retardant containing the phosphinic acid metal salt and / or phosphate metal salt is used in combination with boehmite, the reaction product of this with a polyisocyanate compound becomes a flame-retardant rigid polyurethane foam in which the generation of voids and cracks in the carbonized layer during combustion is suppressed.

[0056] <Polyisocyanate compounds> The polyisocyanate compound is an isocyanate compound having two or more isocyanate groups, and produces a polyurethane resin by a polyaddition reaction with the polyol compound. The polyisocyanate compound may be either an aromatic polyisocyanate or an aliphatic polyisocyanate, and one of these may be used alone or two or more of them may be used in combination.

[0057] 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, monomeric MDI such as 2,2'-MDI, 2,4'-MDI and 4,4'-MDI, crude MDI and polymeric MDI are preferred, and among these, from the viewpoints of availability, cost and the like, crude MDI and polymeric MDI are preferably used.

[0058] The amount of the polyisocyanate compound in the raw material liquid for the 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, ease of handling when mixing the raw material liquid, and the like, 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 relative to 100 parts by mass of the polyol composition.

[0059] <Method for manufacturing flame-retardant rigid polyurethane foam> The molding and foaming method in the method for producing the flame-retardant rigid polyurethane foam is not particularly limited, and may be any known method such as slab molding, mold molding, laminate molding, injection molding, spray foaming, etc. In each of these molding and foaming methods, the polyol composition and the polyisocyanate compound are mixed, foamed, and cured, to produce a rigid polyurethane foam having excellent flame retardancy and suppressing the generation of voids and cracks in the carbonized layer during combustion. EXAMPLES

[0060] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0061] [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: Terephthalic acid-based polyester polyol; "Maximol (registered trademark) RFK-556", manufactured by Kawasaki Kasei Chemical Industries, Ltd.; hydroxyl value 224 mg KOH / g Mannich polyol: "Exenol (registered trademark) NB-622", manufactured by AGC Corporation, hydroxyl value 500 mg KOH / g EDA (ethylenediamine)-based polyether polyol: "Sannix NL-30", manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 745 mg KOH / g <Flame retardants> (a) Furan CM: A powdered flame retardant containing a phosphinic acid metal salt; Furan CM-6R, manufactured by Daiwa Chemical Industry Co., Ltd. TCPP: Tris(β-chloropropyl)phosphate; "TMCPP", manufactured by Daihachi Chemical Industry Co., Ltd. <Foaming agent> HCFO: trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd); "Solstice (registered trademark) LBA", manufactured by Honeywell International, Inc. ·water <Catalyst> Tertiary amine catalyst (1): "TOYOCAT (registered trademark)-SX60", manufactured by Tosoh Corporation Tertiary amine catalyst (2): "TOYOCAT (registered trademark)-DM70", manufactured by Tosoh Corporation Nurate catalyst: Potassium 2-ethylhexylate, "Dabco (registered trademark) K-15", manufactured by Evonik <Boehmite> "Apillar (registered trademark) AOH-60", manufactured by Navaltec; D50: 0.9 μm It should be noted that D50 is the median diameter determined by the laser diffraction scattering method (hereinafter the same). <Aluminum hydroxide> "C-301N", manufactured by Sumitomo Chemical Co., Ltd., D50: 1.5 μm <Foam stabilizer> Silicone foam stabilizer: "Niax(R) silicone L-6100" manufactured by Momentive Performance Materials, Inc.

[0062] Example 1 Into a 500 mL plastic bottle were placed 34.2 parts by mass of polyester polyol, 1.5 parts by mass each of the tertiary amine catalysts (1) and (2) and the nurate catalyst, 0.3 parts by mass of water (blowing agent), 15.0 parts by mass of TCPP, and 1.5 parts by mass of a foam stabilizer, and the mixture was stirred at 3000 rpm for 20 seconds with an electric drill equipped with a cage stirrer (the stirring method was the same below). To this, 15.0 parts by mass of flame retardant (a) (furan CM) and 10.0 parts by mass of boehmite were added and stirred for 20 seconds, and then 19.5 parts by mass of HCFO was added and stirred for another 20 seconds, and then the mixture was kept warm in a thermostatic water bath at 20°C to prepare a polyol composition.

[0063] (Examples 2 to 9, Comparative Examples 1 to 4) Polyol compositions were prepared in the same manner as in Example 1 using the raw material compositions shown in Table 1 below. In Comparative Example 2, aluminum hydroxide was used instead of boehmite.

[0064] [Production of rigid polyurethane foam] Using the polyol compositions of the above Examples and Comparative Examples, rigid polyurethane foams were produced as follows. The polyisocyanate compound used was polymethylene polyphenyl polyisocyanate (Polymeric MDI); "Millionate (registered trademark) MR-200" manufactured by Tosoh Corporation. 100 parts by mass of the polyol composition that had been stirred to homogenize and 102.5 parts by mass of the polyisocyanate compound were placed in a 500 mL desscup and stirred for 5 seconds. The resulting mixture (raw material liquid for rigid polyurethane foam) was then poured into a 15 cm square mold and allowed to stand for 30 minutes before being demolded to obtain a rigid polyurethane foam.

[0065] [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 summarized in Table 1 below.

[0066] <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 calorimeter ("Cone Calorimeter III", manufactured by Toyo Seiki Seisakusho Co., Ltd.; non-combustible base material: gypsum board (thickness 9.5 mm)) was used to measure 50KW / m 2 The heat quantity was applied to the sample, and at the same time, ignition was performed for 10 seconds using an ignition plug. The total heat generation amount after heating for 20 minutes was measured. These measured values ​​were evaluated based on the following evaluation criteria. (Evaluation Criteria) A: Total calorific value 8MJ / m 2 less than B: Total heat output 8MJ / m 2 More than 11MJ / m 2 less than C: Total heat output 11MJ / m 2 More than 20MJ / m 2 less than D: Total heat output 20MJ / m 2 End In the case of rating A, the material has the highest flame retardancy and can be called a non-combustible material. In the case of rating B, the material also has a sufficiently high flame retardancy and can be called a semi-non-combustible material.

[0067] <Carbonized layer properties> After the test using the cone calorimeter in the above flame retardancy evaluation, the sample was cut in the thickness direction with a cutter, and the cross section and outer surface of the charred layer were visually observed. These observation results were evaluated based on the following evaluation criteria. (Evaluation Criteria) A: No voids were observed in the carbonized layer. B: Voids were observed within the carbonized layer, but no cracks were observed on the outer surface of the carbonized layer. C: Cracks originating from voids were observed on the outer surface of the carbonized layer. D: Burned down, with almost no charred layer remaining. In the cases of evaluations A and B, the carbonized layer is well maintained and sufficient heat insulating performance can be sustained. On the other hand, in the cases of evaluations C and D, the carbonization is not well fixed and a sufficient carbonized layer is not formed to sustain heat insulating performance.

[0068] [Table 1]

[0069] As can be seen from the results shown in Table 1, it was found that by using a polyol composition that combines a powdered flame retardant containing a phosphinic acid metal salt with boehmite (Examples 1 to 9), a rigid polyurethane foam can be obtained that has flame retardancy equivalent to or greater than that of a quasi-noncombustible material and in which the generation of voids and cracks in the carbonized layer during combustion is suppressed. In addition, when a Mannich polyol was also used as a polyol compound (Examples 6 to 9), the powdery flame retardant and boehmite were less likely to settle, the polyol composition was easier to handle than when no Mannich polyol was added, and the stirring and mixing operation during the production of rigid polyurethane foam was easier.

Claims

1. A polyol composition for use in producing a flame-retardant rigid polyurethane foam, comprising: Contains a polyol compound, a flame retardant and boehmite, The polyol compound includes an aromatic polyester polyol, The flame retardant contains a phosphinic acid metal salt represented by the following formula (1): The polyol composition contains the boehmite in an amount of 5 to 150 parts by mass per 100 parts by mass of a total of solid contents in the flame retardant. 【Chemistry 1】 In formula (1), M is Mg, Al, Ca, Ti or Zn, and R 1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a phenyl group, and n is 2, 3, or 4.

2. The polyol composition of claim 1 , wherein the polyol compound comprises a Mannich polyol.

3. The polyol composition according to claim 1 or 2, further comprising a blowing agent.

4. The polyol composition of claim 3, wherein the blowing agent comprises at least one of a hydrofluoroolefin and a hydrochlorofluoroolefin.

5. The polyol composition according to any one of claims 1 to 4, further comprising a catalyst.

6. The polyol composition according to any one of claims 1 to 5, further comprising a foam stabilizer.

7. 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.

8. 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.

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