Method for producing polyol composition and method for producing flame-retardant rigid polyurethane foam

Abstract

To provide a method for producing a polyol composition comprising a powder flame retardant which can obtain a hard polyurethane foam excellent in flame retardancy in which precipitation and agglomeration of a powder in the polyol composition is suppressed during storage or transportation and stirring performance and workability are improved with an easy-to-handle viscosity when forming a flame-retardant hard polyurethane foam and to provide a method for producing a flame-retardant hard polyurethane foam using the polyol composition.SOLUTION: There is provided a method for producing a polyol composition which comprises a step 1 of preparing and storing a preliminary composition comprising a polyol compound, a powder flame retardant and an antisettling agent and a step 2 of adding a viscosity-reducing agent to the stored preliminary composition to obtain a polyol composition, in a method for producing a polyol composition used for the production of a flame-retardant hard polyurethane foam.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a polyol composition used in the production of a flame-retardant rigid polyurethane foam, and a method for producing a flame-retardant rigid polyurethane foam using the polyol composition. [Background technology]

[0002] 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.

[0003] Known flame retardants include powder flame retardants such as red phosphorus, phosphates, and phosphinates. These powder flame retardants are prone to settling and aggregation in the raw material liquid of flame-retardant rigid polyurethane foam, so anti-settling agents are used in combination from the viewpoints of storage stability, on-site workability, and the like. For example, Patent Document 1 describes the incorporation of metal oxide fine particles as a sedimentation inhibitor for red phosphorus, while Patent Document 2 describes the addition of finely divided silica to enhance the thixotropy of a polyol composition, which is a raw material liquid for a flame-retardant rigid polyurethane foam, and to improve storage stability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-63396 A [Patent Document 2] JP 2017-78167 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, simply adding the above-mentioned anti-settling agent to the polyol composition does not necessarily provide a sufficient effect of inhibiting the aggregation of solid components (powder) such as powder flame retardants, and there was a problem that a large workload, such as stirring, is required to redisperse the powder in the raw material liquid of the flame-retardant rigid polyurethane foam when applying the rigid polyurethane foam.

[0006] Furthermore, in on-site construction using spray foaming or the like, small equipment with low pumping capacity for the raw material liquid is sometimes used, and the raw material liquid is required to have a low viscosity to ensure smooth supply. However, if the viscosity of the polyol composition, which is the raw material liquid of the flame-retardant rigid polyurethane foam, is low, settling or aggregation of powder in the polyol composition is likely to occur when the composition is left stationary during storage or due to vibration during transportation to the construction site.

[0007] Therefore, the polyol composition is required to suppress settling and aggregation of powder in the polyol composition during storage or transportation, and to have a viscosity that is easy to handle and good stirrability and workability when applied to a flame-retardant rigid polyurethane foam.

[0008] The present invention has been made to solve the above-mentioned technical problems, and aims to provide a polyol composition containing a powder flame retardant, which suppresses settling and aggregation of powder in the polyol composition during storage or transportation, and which has a viscosity that is easy to handle and has good stirrability and workability when applied to a flame-retardant rigid polyurethane foam, and a method for producing a polyol composition that can obtain a rigid polyurethane foam with excellent flame retardancy, and a method for producing a flame-retardant rigid polyurethane foam using the polyol composition. [Means for solving the problem]

[0009] The present invention is based on the discovery that, in a polyol composition containing a powder flame retardant, the application of a viscosity reducing agent during construction of a flame-retardant rigid polyurethane foam can suppress settling and aggregation of the powder during storage or transportation, and can provide the flame-retardant rigid polyurethane foam with good stirrability and workability during construction, as well as excellent flame retardancy.

[0010] That is, the present invention provides the following [1] to [9]. [1] A method for producing a polyol composition used in the production of a flame-retardant rigid polyurethane foam, comprising: step 1 of preparing and storing a preliminary composition containing a polyol compound, a powdery flame retardant, and an anti-settling agent; and step 2 of adding a viscosity reducer to the stored preliminary composition to obtain a polyol composition. [2] The method for producing a 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 method for producing a polyol composition according to the above [1] or [2], wherein the viscosity reducer is a phosphate group-containing polymer-type viscosity reducer. [4] The method for producing a polyol composition according to any one of the above [1] to [3], wherein the anti-settling agent comprises at least one selected from organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax. [5] The method for producing a polyol composition according to any one of the above [1] to [4], wherein the polyol compound comprises a Mannich polyol. [6] The method for producing a polyol composition according to any one of the above [1] to [5], wherein the preliminary composition contains a dispersant. [7] The method for producing a polyol composition according to any one of the above [1] to [6], wherein the preliminary composition contains one or more selected from a blowing agent, a catalyst and a foam stabilizer. [8] The method for producing a polyol composition according to the above [7], wherein the blowing agent comprises at least one selected from hydrofluoroolefins and hydrochlorofluoroolefins.

[0011] [9] A method for producing a flame-retardant rigid polyurethane foam, comprising the steps of mixing a polyol composition produced by the method for producing a polyol composition described in any one of the above [1] to [8] with a polyisocyanate compound at a production site of the flame-retardant rigid polyurethane foam immediately before construction, and foaming and curing the mixture. Effect of the Invention

[0012] According to the present invention, it is possible to produce a polyol composition and a flame-retardant rigid polyurethane foam that can suppress settling and aggregation of powder in the polyol composition during storage or transportation, and that has an easy-to-handle viscosity, good stirrability and workability when applied to produce a flame-retardant rigid polyurethane foam, thereby producing a rigid polyurethane foam with excellent flame retardancy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The process for producing the polyol composition and the process for producing the flame-retardant rigid polyurethane foam of the present invention will be described in detail below.

[0014] [Method of producing polyol composition] The method for producing a polyol composition of the present invention is a method for producing a polyol composition used in producing a flame-retardant rigid polyurethane foam, and includes step 1 of preparing and storing a preliminary composition containing a polyol compound, a powdery flame retardant, and an anti-settling agent, and step 2 of adding a viscosity reducer to the stored preliminary composition to obtain a polyol composition. In this way, by producing the polyol composition by post-adding the viscosity reducing agent, it is possible to suppress settling and aggregation of powder in the preliminary composition of the polyol composition during storage or transportation, and when the flame-retardant rigid polyurethane foam is applied, the viscosity is easy to handle, and the stirrability and application properties are good, making it possible to obtain a rigid polyurethane foam with excellent flame retardancy.

[0015] [Process 1] In step 1, a preliminary composition including a polyol compound, a powder flame retardant, and an anti-settling agent is prepared and stored. The preliminary composition thickened by the anti-settling agent tends to maintain a state in which the settling and aggregation of the powder is suppressed, and therefore, by storing the polyol composition in the form of a preliminary composition, it is possible to suppress the settling and aggregation of the powder caused by the static state during storage and the vibration during transportation to the construction site.

[0016] <Polyol compound> Polyol compounds are the main raw material components of flame-retardant rigid polyurethane foams. Polyol compounds are alcohol compounds with two or more hydroxyl groups, and produce polyurethane resins through a polyaddition reaction with polyisocyanate compounds.

[0017] 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.

[0018] 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 further preferably 180 to 700 mgKOH / g.

[0019] The polyol compound more preferably includes a Mannich polyol, and further preferably includes an aromatic polyester polyol and a Mannich polyol. From the viewpoint of suppressing the aggregation of powder in the preliminary composition and the polyol composition, the polyol composition may contain a dispersant as described below. Furthermore, by containing a Mannich polyol as a polyol compound together with the dispersant, the aggregation of powder can be suppressed more effectively.

[0020] The polyol compound may contain, for example, aromatic polyether polyol other than Mannich polyol, in addition to polyester polyol and Mannich polyol. In addition, from the viewpoint of obtaining a rigid polyurethane foam having excellent flame retardancy, it is preferable that the aliphatic polyol is not contained as much as possible. The total content of aromatic polyol in 100 parts by mass of 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.

[0021] From the viewpoint of obtaining a flame-retardant rigid polyurethane foam having excellent flame retardancy and appropriate hardness, the total content of the polyol compounds in the preliminary 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.

[0022] (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, bisphenol A, and the like. Examples of aromatic polyester polyols include those obtained by transesterifying polyalkylene terephthalates such as polyethylene terephthalate and polybutylene terephthalate with polyhydric alcohols.

[0023] From the viewpoint of obtaining a rigid polyurethane foam having excellent flame retardancy, it is preferable that the polyol compound contains aromatic polyester polyol in the largest proportion, 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.

[0024] (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, and the like 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.

[0025] 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 preliminary composition and the polyol composition and obtaining a rigid polyurethane foam having excellent flame retardancy. From the same viewpoint, the ratio of the content of the Mannich polyol to the content of the aromatic polyester polyol is preferably 0.02 to 1.00, more preferably 0.05 to 0.80, and further preferably 0.08 to 0.50.

[0026] <Powder flame retardant> The powder flame retardant used in the precomposition may be any powder flame retardant known in the art for flame retardant rigid polyurethane foams. 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.

[0027] Examples of the powder flame retardant include red phosphorus, phosphates, phosphinates, etc. Among these, from the viewpoints of safety during handling, ease of suppressing precipitation and aggregation, and imparting excellent flame retardancy to the rigid polyurethane foam, it is preferable to include one or more selected from phosphates and phosphinates. The powder flame retardant may be used alone or in combination of two or more.

[0028] 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 the various phosphoric acids include orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and the like. In addition, organic phosphoric acids such as alkyl phosphoric acids may also 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.

[0029] 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.

[0030] 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.

[0031] The powder flame retardant is preferably used 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, from the viewpoint of obtaining a rigid polyurethane foam having excellent flame retardancy.

[0032] <Liquid flame retardant> The pre-composition preferably includes a liquid flame retardant in addition to the powder 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.

[0033] 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.

[0034] When the preliminary composition contains a liquid flame retardant, 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.

[0035] <Anti-settling agent> The anti-settling agent has the role of suppressing the settling of powder particles having a large specific gravity, such as the powdered flame retardant in the preliminary composition and the polyol composition, and is also called a thixotropic agent. Although the details of the mechanism of action of anti-settling agents are not clear, it is speculated that they act to suppress the settling of powder by thickening the preliminary composition through the formation of hydrogen bonds in the preliminary composition, the formation of cross-linked structures via the adsorptive groups of the powder particles, the entanglement of polymer chains, etc. Hydrogen bonds, cross-linked structures, and entanglement of polymer chains retain their thickening effect when left stationary during storage or under vibration during transportation, but are thought to be released when a strong shear force is applied, such as by stirring. The viscosity of the preliminary composition, measured with a TV viscometer at a rotation speed of 6 rpm and at 25° C., is preferably 3000 mPa s or more, more preferably 3500 mPa s or more, and even more preferably 4000 mPa s or more. From the viewpoint of stirrability, the upper limit of the viscosity of the preliminary composition is preferably 10000 mPa s or less.

[0036] 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 their content in the preliminary polyol composition is small. The content of the anti-settling agent in the preliminary 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, based on 100 parts by mass of the polyol composition.

[0037] Carbon black, silica powder, and the like are known as anti-settling agents for red phosphorus, but when a powder flame retardant containing one or more selected from phosphates and phosphinates is used, these have a thickening effect but tend to easily cause powder aggregation. For this reason, the anti-settling agent to be used in combination with the powder flame retardant is preferably one or more selected from organic bentonite, aliphatic amide wax, and hydrogenated castor oil wax.

[0038] 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 a high affinity with polyol compounds and exerts an excellent sedimentation suppressing effect on the powder in the preliminary 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 preliminary composition of the polyol composition.

[0039] <Dispersant> The preliminary composition preferably includes a dispersant. The dispersant plays a role in preventing the powder particles in the preliminary composition and the polyol composition from agglomerating and caking or gelling. By using a dispersant in combination with an anti-settling agent, settling and aggregation of powder in the preliminary composition can be effectively suppressed.

[0040] The dispersant in the present invention acts to suppress the aggregation of powder by adsorbing to the surface of powder particles in the preliminary composition and generating distance between the powder particles due to steric hindrance. By using a dispersant, even if the powder in the preliminary composition has once settled, the powder can be easily dispersed by re-stirring the preliminary composition. When the preliminary composition contains a dispersant, its content may be smaller than that of the anti-settling agent, and 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.

[0041] The dispersant is a polymer type dispersant having a main chain of polyester, polyether, polycarboxylic acid, or the like, and preferably has a group that is easily adsorbed to the powder flame retardant (excluding phosphate groups), such as a polymer type dispersant of an organic ammonium salt. The dispersant may be used alone or in combination of two or more kinds.

[0042] <Preparation / Storage> The preparation operation of the preliminary composition is not particularly limited, and the components to be contained in the preliminary composition are blended, and the components are stirred and mixed using a known stirring device such as a homodisper or a planetary stirrer to disperse the powder, thereby obtaining the preliminary composition. The resulting preliminary composition is usually stored in a sealed container and allowed to stand at room temperature and normal pressure. The period until use of the polyol composition, including storage and transportation to the construction site, ie, the retention period in the state of a preliminary composition, is usually within about 20 days, and preferably 1 to 10 days.

[0043] [Process 2] In step 2, a viscosity reducing agent is added to the stored preliminary composition to obtain a polyol composition. The stored preliminary composition has a high viscosity, and it is difficult to mix it as it is with a polyisocyanate compound at the construction site of the flame-retardant rigid polyurethane foam to obtain a homogeneous raw material liquid for the rigid polyurethane foam. For this reason, in the present invention, a viscosity reducer is added to the preliminary composition to prepare a polyol composition, which is then used to produce a flame-retardant rigid polyurethane foam. By producing a polyol composition through such steps, the stirrability of the mixed liquid with the polyisocyanate compound is improved, and a flame-retardant rigid polyurethane foam having excellent workability and flame retardancy can be obtained. The stored preliminary composition may be used as it is at the storage location, or may or may not be subjected to strong shear such as forced stirring after storage, and may be used after being transported to the construction site of the flame-retardant rigid polyurethane foam.

[0044] <Thickening agent> The viscosity reducer serves to reduce the viscosity of the preliminary composition and to improve the stirrability of the polyol composition and the raw material liquid for the flame-retardant rigid polyurethane foam. It is presumed that the viscosity reducer adsorbs to the surfaces of powder particles in the polyol composition, creating distance between the powder particles due to electrical repulsion, thereby weakening the interaction between the powder particles, thereby reducing the viscosity of the polyol composition. The content of the viscosity reducer in the polyol composition may be approximately the same as that of the dispersant, and 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.

[0045] The viscosity reducing agent is preferably a polymer type viscosity reducing agent having a main chain of polyester, polyether, polycarboxylic acid, etc., has a group that is easily adsorbed to the powder flame retardant, and is easily capable of generating electrical repulsion between the powder particles in the polyol composition as described above, and is preferably one having a phosphate group, for example. The phosphate group is also easily adsorbed to the anti-settling agent, and is considered to have a viscosity reducing effect that provides good stirrability of the polyol composition by inhibiting the thickening effect of the anti-settling agent. Therefore, the viscosity reducing agent is preferably a phosphate group-containing polymer type viscosity reducing agent, and for example, a phosphate group-containing salt polymer type viscosity reducing agent, a phosphate ester polymer type viscosity reducing agent, a phosphate ester salt polymer type viscosity reducing agent, etc. The viscosity reducing agent may be used alone or in combination of two or more types.

[0046] <Other ingredients> As the raw materials for producing a flame-retardant rigid polyurethane foam, it is preferable to blend a blowing agent, a catalyst, a foam stabilizer, etc., in addition to the main raw materials, that is, a polyol compound, a flame retardant, and a polyisocyanate compound. These components may be added separately from the polyol composition when producing a flame-retardant rigid polyurethane foam, but from the viewpoint of reducing the workload during application of the flame-retardant rigid polyurethane foam, it is preferable that they are contained in the preliminary composition or the polyol composition, and more preferably, from the viewpoint of further reducing the workload during application, they are contained in the preliminary composition. That is, it is preferable to add one or more selected from a blowing agent, a catalyst, and a foam stabilizer when preparing the preliminary composition in step 1. Furthermore, the preliminary composition or 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.

[0047] (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, etc. These may be used alone or in combination of two or more. Among 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, etc., 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), etc.

[0048] The isocyanate group of the polyisocyanate compound reacts with water to form a urea bond, and a foaming reaction that generates carbon dioxide gas also occurs. Water induces foaming in the initial stage of the production reaction of the rigid polyurethane foam, and from the viewpoint of reducing the density of the rigid polyurethane foam produced, water may be contained as a foaming agent.

[0049] The amount of the foaming agent 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, based on 100 parts by mass of the polyisocyanate compound, from the viewpoint of appropriately foaming the polyurethane resin. 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.

[0050] (catalyst) In the reaction for producing rigid polyurethane foam, from the viewpoint of promoting the resinification reaction and the foaming reaction, a tertiary amine catalyst, a metal-based urethane catalyst, etc. are preferably used. In addition, from the viewpoint of improving flame retardancy by partial nuration, a nurate catalyst (trimerization catalyst) is also preferably used. 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.

[0051] 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 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.

[0052] 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 urethane catalyst added is preferably 0.01 to 2.0 parts by mass, more preferably 0.02 to 1.0 parts by mass, and even more preferably 0.05 to 0.5 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.

[0053] 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 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.

[0054] (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 foam stabilizer 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.

[0055] The operation for producing the polyol composition in step 2 can be carried out in the same manner as for preparing the preliminary composition. That is, the polyol composition can be obtained by appropriately adding the viscosity reducer and the other components described above to the preliminary composition and stirring and mixing them using a stirring device similar to that used for preparing the preliminary composition.

[0056] [Method of manufacturing flame-retardant rigid polyurethane foam] The method for producing a flame-retardant rigid polyurethane foam of the present invention includes a step of mixing the polyol composition produced by the above-mentioned method for producing a polyol composition with a polyisocyanate compound at a production site of the flame-retardant rigid polyurethane foam immediately before construction, and foaming and curing the mixture. By using the polyol composition obtained by the method for producing a polyol composition of the present invention to prepare a raw material liquid for a flame-retardant rigid polyurethane foam, i.e., a mixed liquid of the polyol composition and a polyisocyanate compound, immediately before construction at the site where the flame-retardant rigid polyurethane foam is produced, a uniform raw material liquid having excellent stirrability and workability for the flame-retardant rigid polyurethane foam can be easily obtained, and a homogeneous rigid polyurethane foam having excellent overall flame retardancy can be obtained.

[0057] <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 a 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.

[0058] 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. Of 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 or 4,4'-MDI, crude MDI or polymeric MDI is used, and further, from the viewpoints of availability, cost, etc., crude MDI or polymeric MDI is more preferably used.

[0059] The content 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, stirrability of the raw material liquid, and workability of the flame-retardant rigid polyurethane foam, the content 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.

[0060] <Foaming and hardening> The foaming and curing method for obtaining the flame-retardant rigid polyurethane foam is not particularly limited, and for example, various molding methods such as slab molding, mold molding, laminate molding, injection molding, etc., as well as known methods such as spray foaming, etc. In these various molding and foaming methods, a raw material liquid for the flame-retardant rigid polyurethane foam, which is a mixture of a polyol composition and a polyisocyanate compound, is foamed and cured to obtain a homogeneous rigid polyurethane foam having excellent flame retardancy overall.

[0061] The mixing operation in preparing the raw material liquid for the flame-retardant rigid polyurethane foam can be performed in the same manner as in preparing the preliminary composition. That is, the raw material liquid can be obtained by stirring and mixing the polyol composition and the polyisocyanate compound using a stirring device similar to that used in preparing the preliminary composition. Alternatively, in the case of spray foaming, the polyol composition and the polyisocyanate compound can be simultaneously fed to a spray foaming device and foamed while being mixed. EXAMPLES

[0062] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0063] [Production of rigid polyurethane foam] Details of each raw material used in the production of rigid polyurethane foams in the following Examples and Comparative Examples are given below. <Polyol compound> Polyester polyol (RFK-556): 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 (NB-622): "Exenol (registered trademark) NB-622", manufactured by AGC Corporation, hydroxyl value 500 mg KOH / g <Powder flame retardant> Phosphinic acid salt (CM-6R): "Furan CM-6R", manufactured by Yamato Chemical Industry Co., Ltd.; nitrogen-containing compound <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® 38", manufactured by Elementis Specialties, Inc., powder <Dispersant> Organic ammonium salt (BYK-2155): "DISPERBYK (registered trademark; hereinafter the same)-2155", BYK Japan Co., Ltd.; block copolymer having basic groups <Thickening agent> Phosphate-containing salt polymeric viscosity reducer (BYK-180): "DISPERBYK-180", BYK Japan Co., Ltd.; alkylol ammonium salt of copolymer containing phosphate group Phosphate ester polymer type viscosity reducer (BYK-111): "DISPERBYK-111", BYK Japan Co., Ltd.; Phosphate ester with phosphate groups at both ends of the copolymer Phosphate ester salt polymer type viscosity reducer (BYK-145): "DISPERBYK-145", BYK Japan Co., Ltd.; Copolymer of phosphate ester salt <Polyisocyanate compounds> Polymethylene polyphenyl polyisocyanate (Polymeric MDI): "Millionate (registered trademark) MR-200", manufactured by Tosoh Corporation <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(R) silicone L-6100", manufactured by Momentive Performance Materials, Inc.

[0064] Example 1 27.58 parts by mass of polyester polyol RFK-556 as a polyol compound and 20.16 parts by mass of liquid flame retardant TMCPP were placed in a 500 mL plastic bottle and stirred for 20 seconds at 3000 rpm with an electric drill equipped with a cage-type attachment (the stirring method was the same below). To this was added 30.0 parts by mass of powder flame retardant CM-6R, 0.76 parts by mass of anti-settling agent BENTONE 38, 0.46 parts by mass of dispersant BYK-2155, 14.0 parts by mass of foaming agent (HCFO) LBA, 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, and 1.4 parts by mass of foam stabilizer L-6100, and the mixture was stirred for 20 seconds to prepare a preliminary composition. The preliminary composition was stored at 20°C for 7 days, after which 0.46 parts by mass of BYK-180 was added as a viscosity reducer and stirred for 20 seconds to prepare a polyol composition. The storage period of the preliminary composition was set at 7 days, taking into consideration the time required for preparation at the construction site of the flame-retardant rigid polyurethane foam and the time required for preparation and transportation of the raw material liquid. Next, 100 parts by mass of the polyol composition was stirred at 15° C., and placed in a 1 L descup together with 90 parts by mass of the polyisocyanate compound, and mixed and foamed for 5 seconds. After standing for 30 minutes, the cured product was removed from the descup to obtain a rigid polyurethane foam.

[0065] (Examples 2 to 6) The raw material composition of the polyol composition shown in Table 1 below was used, and the preparation of the polyol composition and the production of a rigid polyurethane foam were carried out in the same manner as in Example 1.

[0066] (Comparative Examples 1 to 5) A polyol composition was prepared and a rigid polyurethane foam was produced in the same manner as in Example 1, except that no viscosity reducer was added, using the raw material blending composition of the polyol composition shown in Table 1 below.

[0067] (Comparative Examples 6 to 8) The raw material composition of the polyol composition shown in Table 1 below was prepared by adding a viscosity reducer and a dispersant at the same time, and then storing the mixture for 7 days. The rest of the procedure was the same as in Example 1, and the polyol composition was prepared and a rigid polyurethane foam was produced.

[0068] [evaluation] The preliminary compositions, polyol compositions, raw material liquids (mixtures) for rigid polyurethane foams prepared in the above examples and comparative examples, and rigid polyurethane foams produced using the mixtures were evaluated for the following items. The evaluation results are shown in Table 1 below.

[0069] <Sedimentation> 30 g of each of the preliminary compositions of Examples 1 to 6 or the polyol compositions of Comparative Examples 1 to 8 was placed in a 50 mL vial and allowed 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 storage for 7 days was measured. These measured values ​​were evaluated based on the following evaluation criteria. (Evaluation Criteria) A: The height of the top surface of the sediment is less than 1 mm above the liquid surface. B: The height of the top surface of the sediment is 1 mm or more but less than 3 mm above the liquid surface. C: The height of the top surface of the sediment is 3 mm or more but less than 5 mm above the liquid surface. D: The height of the top surface of the sediment is 5 mm or more above the liquid surface. In the case of evaluation A, it can be considered that almost no sedimentation has progressed. In the case of evaluation B, it can be said that sedimentation has been well suppressed. In the case of evaluation C, it was determined that sedimentation has progressed, and in the case of evaluation D, it was determined that sedimentation has progressed significantly.

[0070] <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) A: If you turn the vial on its side, the sediment will flow smoothly. B: When the vial is turned on its side, some of the sediment moves. In the case of evaluation A, it was determined that the aggregation of powder was well suppressed, while in the case of evaluation B, it was determined that a sufficient aggregation suppression effect was not obtained.

[0071] <Viscosity> The polyol composition, which had been homogenized by stirring during the preparation of the mixed liquid, was allowed to stand for 2 hours, and then the average value for 5 to 7 minutes after the start of measurement was recorded using a TV-25 viscometer (manufactured by Toki Sangyo Co., Ltd.; temperature 25°C, THM type rotor, rotation speed 6 rpm). If the viscosity of the polyol composition is 300 to 3200 mPa·s, it can be said that the polyol composition has good handleability when preparing a mixed liquid with a polyisocyanate compound. The viscosity is preferably 400 to 3000 mPa·s, and more preferably 500 to 2500 mPa·s.

[0072] <Mixing ability> The stirring state during preparation of the raw material liquid (mixture) of the rigid polyurethane foam was evaluated based on the following evaluation criteria. (Evaluation Criteria) A: It can be easily stirred and a uniform mixture is obtained. B: The mixture can be stirred easily, but the sediment is not uniformly dispersed. C: Stirring is possible, but flocculated sediment remains. D: The sediment clumps together and stirring is difficult. In the case of evaluation A or B, the stirrability of the mixture was deemed to be good. In the case of evaluation C or D, the stirrability of the mixture was deemed to be poor.

[0073] <Workability> Using a spray foaming machine, the raw material liquid (mixed liquid) was discharged at a pressure of 6-8 MPa and a liquid temperature of 38-40°C, and sprayed perpendicularly onto the flat surface of a fiber-reinforced cement board (910 mm x 910 mm, thickness 8 mm) held vertically at a temperature of 15±3°C to produce rigid polyurethane foam. The workability of the produced rigid polyurethane foam was evaluated based on the following evaluation criteria. (Evaluation Criteria) A: The spray pattern is always circular and stable. The application surface is flat. B: The spray pattern is almost circular, but sometimes elliptical. There are some unevenness in the applied surface. C: The spray pattern is always elliptical or linear. The entire application surface is uneven. In the case of evaluation A or B, it can be said that the workability during production of the rigid polyurethane foam is good. In the case of evaluation C, the workability was judged to be poor.

[0074] <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 12.5 mm)) was used to measure 50KW / m 2 The heat amount 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 / m2 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. In the cases of rating C or D, the material was judged to not have sufficient flame retardancy.

[0075] [Table 1]

[0076] As can be seen from the results shown in Table 1, by adding a viscosity reducer to a polyol composition containing a powder flame retardant and a settling prevention agent just before application of a flame-retardant rigid polyurethane foam, the settling and aggregation of the powder in the preliminary composition of the polyol composition is suppressed, and when preparing the raw material liquid (mixture) of the rigid polyurethane foam, the polyol composition can be handled with an appropriate viscosity, and the stirrability of the mixture and the application of the flame-retardant rigid polyurethane foam are improved. Furthermore, it was confirmed that the obtained rigid polyurethane foam has flame retardancy equivalent to or higher than that of a non-combustible material. On the other hand, when no viscosity reducing agent was added (Comparative Examples 1 to 5), no good viscosity reducing effect was obtained during preparation of the mixed solution, and no polyol composition was obtained that showed good evaluation results in terms of the stirrability of the mixed solution, the workability of the rigid polyurethane foam, and the flame retardancy. In addition, when a polyol composition was used after adding a viscosity reducing agent together with a settling prevention agent and storing it (Comparative Examples 6 to 8), the powder settled significantly during storage, and no polyol composition with good flame retardancy of the rigid polyurethane foam was obtained.

Claims

1. A method for producing a polyol composition used in producing a flame-retardant rigid polyurethane foam, comprising the steps of: Step 1 of preparing and storing a preliminary composition including a polyol compound, a powder flame retardant, and an anti-settling agent; and step 2 of adding a viscosity reducer to the stored preliminary composition to obtain a polyol composition; The powder flame retardant is at least one selected from a phosphate and a phosphinate, The anti-settling agent is organic bentonite; The viscosity reducing agent is a phosphate group-containing polymer type viscosity reducing agent. A method for producing a polyol composition.

2. The method for producing a polyol composition according to claim 1 , wherein the polyol compound comprises a Mannich polyol.

3. The method for producing a polyol composition according to claim 1 or 2, wherein the preliminary composition contains a dispersant, and the dispersant is a polymer-type dispersant.

4. The method for producing a polyol composition according to any one of claims 1 to 3, wherein the preliminary composition contains at least one selected from a blowing agent, a catalyst, and a foam stabilizer.

5. The method for producing a polyol composition according to claim 4, wherein the blowing agent comprises at least one selected from hydrofluoroolefins and hydrochlorofluoroolefins.

6. A method for producing a flame-retardant rigid polyurethane foam, comprising the steps of mixing a polyol composition produced by the method for producing a polyol composition according to any one of claims 1 to 5 with a polyisocyanate compound at a site where the flame-retardant rigid polyurethane foam is produced immediately before construction, and foaming and curing the mixture.

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