JP2019214651A - Hard polyurethane foam - Google Patents

Abstract

To provide a hard polyurethane foam excellent in appearance and having uniform high fire retardancy easily even when the hard polyurethane foam is spray processed in a site for arranging an adiabatic layer.SOLUTION: In a hard polyurethane foam constituted by a reaction product of a polyol composition containing polyol, a foam stabilizer, a catalyst, a foaming agent and a fire retardant, and an isocyanate composition, polyol contained in the polyol composition contains a bromine-based polyol, and bromine-free aromatic polyester polyol, added amount of the bromine-based polyol is 25 pts.mass to 70 pts.mass when added amount of the polyol is 100 pts.mass, and the bromine-based polyol has an aromatic ring and a skeleton in which at least one or more bromine binds to the aromatic ring.SELECTED DRAWING: None

Description

  The present invention relates to rigid polyurethane foams.

  2. Description of the Related Art In general, various buildings such as concrete buildings are subjected to a heat insulating process to provide a heat insulating layer from the viewpoint of energy saving. For example, in the case of a reinforced concrete building such as an apartment, a heat insulating layer is provided on an indoor side wall surface of the building. Usually, as the heat insulating layer, a foamed material having heat insulating performance such as a rigid polyurethane foam, glass wool, or the like is used. When a rigid polyurethane foam is used, it can be formed by spraying a raw material composition of the rigid polyurethane foam on a predetermined position inside a building such as a concrete surface. Specifically, a polyol composition containing a polyol, a foam stabilizer, a catalyst, a foaming agent, and a flame retardant, and an isocyanate composition are prepared, and the polyol composition and the isocyanate composition are prepared at a building construction site. The mixture is sprayed to a predetermined position inside the building with a spray gun or the like to perform a foaming process of the rigid polyurethane foam, thereby forming a heat insulating layer made of the rigid polyurethane foam.

  However, when a rigid polyurethane foam is sprayed as a heat insulating layer, the rigid polyurethane foam may be ignited when a fire occurs due to static electricity generated during construction work or the like.

  Therefore, Patent Literature 1 proposes a foam formed from a flame-retardant urethane resin composition containing red phosphorus as an essential component. By containing red phosphorus in the flame-retardant urethane resin composition forming the foam, the foam exhibits flame retardancy.

International Publication No. 2014/112394

  Red phosphorus, which is essential in Patent Document 1, is a solid. For this reason, the step of adjusting the flame-retardant urethane resin composition at the site where the heat insulating layer is provided and dispersing the red phosphorus sufficiently and promptly in the flame-retardant urethane resin composition upon applying the hard polyurethane foam. It becomes important. For this reason, in Patent Document 1, when preparing a flame-retardant urethane resin composition at a site where a heat-insulating layer is provided, a mechanical facility for sufficiently and quickly dispersing red phosphorus in the flame-retardant urethane resin composition is provided. It was necessary to newly maintain it, and it was difficult to form a rigid polyurethane foam having low cost and uniform flame retardancy by spraying. In addition, when poor dispersion of red phosphorus occurs in the flame-retardant urethane resin composition, red phosphorus in the obtained rigid polyurethane foam becomes non-uniform, causing a poor appearance such as shrinkage of the rigid polyurethane foam. There is a risk of causing problems such as deformation of the material as a house. The poor appearance of the rigid polyurethane foam, especially when using the rigid polyurethane foam as a heat insulating layer, not only causes non-uniformity of heat insulating property of the heat insulating layer, but also leads to the generation of gaps, and when a fire occurs, This is an important problem because there is a possibility that the inside may burn from the gap.

  The present invention provides a rigid polyurethane foam having excellent appearance and more easily uniform high flame retardancy even when a rigid polyurethane foam is formed by spraying at a site where a heat insulating layer is provided. Aim.

The present invention provides (1) a rigid polyurethane foam comprising a reaction product of a polyol composition containing a polyol, a foam stabilizer, a catalyst, a foaming agent, and a flame retardant, and an isocyanate composition,
The polyol contained in the polyol composition contains a bromine-based polyol and a bromine-free aromatic polyester polyol,
When the addition amount of the polyol is 100 parts by mass, the addition amount of the brominated polyol is 25 parts by mass or more and 70 parts by mass or less,
The rigid polyurethane foam, wherein the bromine-based polyol has an aromatic ring, and has a skeleton in which at least one or more bromines are bonded to the aromatic ring.
(2) The rigid polyurethane foam according to (1), wherein the flame retardant contains red phosphorus.
(3) The rigid polyurethane foam according to (1) or (2), wherein the addition amount of red phosphorus contained in the flame retardant is 17 parts by mass or less when the addition amount of the polyol is 100 parts by mass. Is the gist.

  According to the present invention, even when a rigid polyurethane foam is formed by spraying at a site where a heat insulating layer is provided, the present invention provides a rigid polyurethane foam having an excellent appearance and more easily and uniformly having high flame retardancy. be able to.

[Rigid polyurethane foam]
The present invention is a rigid polyurethane foam. The rigid polyurethane foam is composed of a reaction product of a polyol composition and an isocyanate composition. Further, the rigid polyurethane foam of the present invention has high flame retardancy.

  In the present specification, that the rigid polyurethane foam has high flame retardancy means that the rigid polyurethane foam is a non-combustible material or a quasi-non-combustible material.

  The conditions for the rigid polyurethane foam to be a non-combustible material or a quasi-non-combustible material are to satisfy the following conditions, respectively.

(Conditions for non-combustible material)
The conditions for the rigid polyurethane foam to be a non-combustible material are the following four conditions (conditions) in a heat generation test (cone calorimeter test) conducted at a heating strength of 50 kW / m ² in accordance with ISO5660-1. 1 to 4).

Condition 1: The total amount of heat generated from the start of heating to the elapse of the required time is 8 MJ / m ² or less.
Condition 2: No generation of penetrating cracks or holes is observed even if combustion is continued until the required time has elapsed from the start of heating.
Condition 3: No state where the maximum heat generation rate exceeds 200 kW / m ² and continues for 10 seconds or more from the start of heating to the elapse of the required time is not recognized.
Condition 4: Request time is 20 minutes.

(Conditions for semi-combustible material)
Regarding the condition that the rigid polyurethane foam is a quasi-noncombustible material, except that the condition 4 in the condition for the above noncombustible material is “the required time is 10 minutes”, the conditions for the above noncombustible material are as follows. The same conditions (the same applies to conditions 1 to 3).

[Polyol composition]
The polyol composition includes a polyol, a foam stabilizer, a catalyst, a foaming agent, and a flame retardant.

(Polyol)
As the polyol, an aromatic polyester polyol and a bromine polyol are used.

(Aromatic polyester polyol)
As the aromatic polyester polyol, an aromatic polyester polyol obtained by a normal esterification reaction from a polycarboxylic acid and a polyhydric alcohol, and an aromatic polyester obtained by transesterifying a polyester resin or the like with a polyhydric alcohol Polyols. Examples of the polyvalent carboxylic acid include aromatic polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, trimellitic acid, and anhydrides thereof. These may be used alone or in combination of two or more. The above can be used in an appropriate combination. On the other hand, examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, shoe rose, bisphenol A, and the like. These may be used alone or in combination of two or more. The above can be used in an appropriate combination. Among the polyols, aromatic polyester polyols are suitably used for forming the rigid polyurethane foam of the present invention because of their excellent flame retardancy.

  The aromatic polyester polyol is one containing no bromine, that is, one containing no bromine in the molecular skeleton of the polyol.

(Addition amount of aromatic polyester polyol)
The amount of the aromatic polyester polyol to be added is preferably in the range of 30 parts by mass to 75 parts by mass when the total amount of the polyol contained in the polyol composition is 100 parts by mass. When the total amount of the polyol contained in the polyol composition is 100 parts by mass, and the amount of the aromatic polyester polyol is less than 30 parts by mass, the obtained rigid polyurethane foam becomes non-uniform and the compressive strength of the foam is reduced. When the amount of the aromatic polyester polyol exceeds 75 parts by mass, the content of a bromine-based polyol described below decreases, and it becomes difficult to obtain quasi-noncombustibility of the rigid polyurethane foam.

(Brominated polyol)
The bromine-based polyol has an aromatic ring, and has a skeleton in which at least one or more bromine is bonded to an aromatic ring, and includes bromine-containing polyester polyol and bromine-containing polyether polyol. it can.

  As the bromine-containing polyester polyol, those obtained by an esterification reaction between a bromine-containing polycarboxylic acid such as tetrabromophthalic acid and the above-mentioned polyhydric alcohol can be used.

  Examples of the bromine-containing polyether polyol include, for example, those obtained by addition-polymerizing one or more of a bromine-containing polyhydric alcohol such as tetrabromobisphenol A and an alkylene oxide such as ethylene oxide, propylene oxide, and butylene oxide. Can be used. When a bromine-containing polyether polyol is used in the present invention, it is particularly preferable to use an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton.

  By using a bromine-based polyol as the polyol, an effect of suppressing the spread of fire by the radical trap effect in the formed rigid polyurethane foam is exhibited. In order to exhibit this effect more efficiently, it is preferable to disperse the bromine-based polyol more uniformly in the polyol composition. Therefore, when the bromine-based polyol is added to other raw materials, the viscosity may be adjusted by previously mixing a bromine-based polyol with a phosphate ester or the like, which is also a liquid flame retardant described later. By adjusting the viscosity of the bromine-based polyol, the bromine-based polyol can be more easily mixed with other raw materials.

(Amount of brominated polyol)
The addition amount of the bromine-based polyol is in the range of 25 parts by mass or more and 70 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. When the total amount of the polyol contained in the polyol composition is 100 parts by mass, by adding the bromine-based polyol at 25 parts by mass or more, the flame retardancy can be increased without using many flame retardants. Can be obtained, and by adding the bromine-based polyol in an amount of 70 parts by mass or less, the risk of shrinkage after the rigid polyurethane foam is formed can be effectively prevented, and the appearance is excellent. A rigid polyurethane foam can be formed.

(Other polyols)
As the polyol, other polyols other than the aromatic polyester polyol and the bromine polyol may be contained as long as the effects of the present invention are not impaired.

  Other polyols include aromatic polyether polyols, aliphatic polyester polyols, aliphatic polyether polyols, amine polyether polyols, and polymer polyols.

(Foam stabilizer)
Examples of the foam stabilizer include silicone compounds and fluorine compounds which have been generally used.

  The addition amount of the foam stabilizer is preferably in the range of 0.5 parts by mass or more and 5 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass.

(catalyst)
As the catalyst, amine catalysts, metal catalysts and the like which have been generally used can be used. Examples of the amine catalyst include N, N, N ′, N′-tetramethylhexanediamine, N, N, N ′, N′-tetramethylpropanediamine, N, N, N ′, N ″, N ′. '-Pentamethyldiethylenetriamine, N, N, N', N'-tetramethylethylenediamine, N, N, -dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, triethylenediamine, N, N ', N '-Trimethylaminoethylpiperazine, N, N-dimethylcyclohexylamine, N, N', N ''-tris (3-dimethylaminopropyl) hexahydro-s-triazine, bis (dimethylaminoethyl) ether, N, N- Aminoethoxyethanol, N, N-dimethylaminohexanol, tetramethylhexanediamine, 1-methylimidazole, 1-iso Butyl-2-methylimidazole and the like can be used. As the metal catalyst, for example, stannas octoate; dibutyltin dilaurate; lead octylate; potassium salts such as potassium acetate and potassium octylate; and those containing Zn, Bi, Ti, and the like can be used. In addition to these amine catalysts and metal catalysts, quaternary ammonium salts of fatty acids such as formic acid and acetic acid can also be used. Each of the above catalysts may be used alone or in combination of two or more.
In particular, a trimerization catalyst for trimerizing by reacting an isocyanate group contained in the isocyanate compound is selected. The trimerization catalyst promotes the formation of an isocyanurate ring.

(Trimerization catalyst)
Examples of the trimerization catalyst include a nitrogen-containing aromatic compound, an alkali metal carboxylate, and a quaternary ammonium salt.

(Amount of catalyst added)
The amount of the catalyst added is preferably in the range of 1 part by mass or more and 10 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. When the amount of the catalyst is less than 1 part by mass, the curing reaction of the foam is too slow to form the foam, and when it exceeds 10 parts by mass, the curing reaction is too fast. It causes dents and uneven physical properties. In consideration of this point, the addition amount of the catalyst is more preferably 1.5 parts by mass or more and 8 parts by mass or less.

(Blowing agent)
Examples of the foaming agent include water, hydrocarbons such as normal pentane, isopentane, cyclopentane and isobutane; hydrofluorocarbons such as HFC-365mfc, HFC-245fa and HFC-134a; and 1-chloro-3,3,3, -tri Hydrofluoroolefins such as fluoropropene and 1,1,1,4,4,4-hexafluoro-2-butene can be mentioned, and these can be used alone or in an appropriate combination of two or more.

  When water is selected as the foaming agent, the amount of water to be added may be in the range of 0.5 parts by mass or more and 6 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. preferable. The density of the obtained rigid polyurethane foam is adjusted by the amount of water added. However, if the amount of water added is less than 0.5 parts by mass, the density becomes too high, and the heat generation property described later tends to be inferior. The use amount of the polyurethane foam raw material increases, and the yield decreases. If it exceeds 6 parts by mass, the density is too low and the foam tends to shrink. In consideration of this point, the addition amount of water is more preferably 1 part by mass or more and 4 parts by mass or less.

  The amount of the foaming agent other than water is preferably in the range of 15 parts by mass or more and 60 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. Although the density of the obtained rigid polyurethane foam is adjusted by the amount of the foaming agent added, the desired density is easily obtained within the above range. In consideration of this point, the addition amount of the foaming agent is more preferably from 25 parts by mass to 45 parts by mass.

(Flame retardants)
As the flame retardant contained in the polyol composition, a solid flame retardant and / or a liquid flame retardant is used.

(Solid flame retardant)
A solid flame retardant is a solid flame retardant under an atmosphere at atmospheric pressure and normal temperature (25 ° C.).

  Examples of solid flame retardants include red phosphorus, metal hydroxides, particularly aluminum hydroxide, magnesium hydroxide, zinc borate, ammonium polyphosphate, and antimony oxide. Considering that effective char (carbonized layer) formation during combustion can be promoted and an excellent fire spread prevention effect can be exhibited, red phosphorus is preferably selected as the solid flame retardant.

(Amount of solid flame retardant added)
The addition amount of the solid flame retardant is preferably in a range of 17 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. When the amount of the solid flame retardant is within the range, a rigid polyurethane foam having flame retardancy equal to or higher than quasi-nonflammability can be obtained. If the addition amount of the solid flame retardant is excessively large, precipitation of the solid flame retardant occurs in the polyol composition, which makes it difficult to form a rigid polyurethane foam exhibiting uniform flame retardancy. It is more preferred that: Further, when the addition amount of the solid flame retardant is 5 parts by mass or more and 12 parts by mass or less, a nonflammable material is easily obtained, which is preferable.

(Liquid flame retardant)
A liquid flame retardant is a liquid flame retardant in an atmosphere at atmospheric pressure and normal temperature (25 ° C.).

  Examples of the liquid flame retardant include phosphate esters such as trimethyl phosphate and triethyl phosphate, and halogenated phosphate esters such as trischloroethyl phosphate and trischloropropyl phosphate.

(Amount of liquid flame retardant added)
The amount of the liquid flame retardant to be added is preferably in the range of 30 parts by mass or more and 100 parts by mass or less when the total amount of the polyol contained in the polyol composition is 100 parts by mass. When the amount of the liquid flame retardant is in such a range, it is possible to obtain a rigid polyurethane foam which imparts flame retardancy and does not hinder skeleton formation and hardly shrinks. In consideration of this point, the addition amount of the liquid flame retardant is more preferably not less than 60 parts by mass and not more than 100 parts by mass.

(Other additives)
In addition to the polyol, the foam stabilizer, the catalyst, the foaming agent and the flame retardant, other additives may be added to the polyol composition, if necessary. As other additives, plasticizers, fillers, antioxidants, defoamers, compatibilizers, colorants, stabilizers, ultraviolet absorbers and other additives generally usable in the production of rigid polyurethane foams can be used. I can give it. The amounts of the other additives may be appropriately selected within a range that does not impair the effects of the present invention.

  In addition, you may add a crosslinking agent to a polyol composition as needed. Examples of the crosslinking agent include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, tetramethylene ether glycol, glycerin, pentaerythritol, trimethylolpropane, monoethanolamine, diethanolamine, isopropanolamine, and amino. Alcohols such as ethylethanolamine, sucrose, sorbitol and glucose can be used. In particular, those having three or more functions are preferable.

[Isocyanate composition]
The isocyanate composition contains an isocyanate compound. When mixed with the polyol composition, the isocyanate compound reacts with the polyol to form a urethane bond.

(Isocyanate compound)
The isocyanate compound is not particularly limited as long as it reacts with a polyol to form a urethane bond. Examples of the isocyanate compound include aromatic isocyanates, aliphatic diisocyanates, alicyclic diisocyanates, isocyanate group-terminated prepolymers, and the like.

  More specifically, examples of the isocyanate compound to be reacted with the polyol include diphenylmethane diisocyanate, polymeric MDI (crude MDI), 2,4-tolylene diisocyanate (2,4-TDI), and 2,6-tolylene diisocyanate (2 , 6-TDI), aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate (HDI), alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated TDI, and hydrogenated MDI. Can be used alone or in combination of two or more.

[Formation of rigid polyurethane foam]
The rigid polyurethane foam can be formed, for example, as follows. First, a polyol composition and an isocyanate composition are individually obtained. For example, the polyol composition is obtained by blending various components constituting the polyol composition such as a polyol, a foam stabilizer, a catalyst, a foaming agent, and a flame retardant. The isocyanate composition is obtained by blending various components constituting the isocyanate composition.

  Next, the polyol composition and the isocyanate composition are mixed and sprayed onto a target portion such as a wall surface using a spray gun or the like at a site where a heat insulating layer is provided (spraying step). The reaction between the polyol and the isocyanate compound (urethane reaction) is started by mixing the polyol and the isocyanate compound. After the spraying step, the reaction between the polyol composition and the isocyanate composition progresses with the lapse of time, and the hardening of the sprayed portion progresses to form a rigid polyurethane foam. In this way, a layer of rigid polyurethane foam is formed on the surface of a predetermined place such as a wall surface, and this layer forms a heat insulating layer. The heat-insulating layer made of the rigid polyurethane foam is a layer having high flame retardancy because the polyol used for forming the heat-insulating layer is an aromatic polyester polyol and a specific bromine-based polyol.

  Further, when red phosphorus, which is a solid flame retardant, is used as the flame retardant of the polyol composition, since the bromine-based polyol is contained in the polyol composition, even if the addition amount of the solid flame retardant is suppressed, a high level of difficulty is obtained. Flammability can be obtained, and sedimentation of the solid flame retardant is suppressed. And since the sedimentation of the solid flame retardant is suppressed, even when preparing the polyol composition, and even when mixing the polyol composition and the isocyanate composition, the solid flame retardant is more effectively dispersed. It is easy to form a state in which the solid flame retardant is uniformly dispersed in the rigid polyurethane foam. Then, a layer having uniform high flame retardancy can be formed as a heat insulating layer made of a rigid polyurethane foam.

  Next, the present invention will be further described using examples.

  An isocyanate composition was prepared. Further, a polyol, a foam stabilizer, a catalyst, a foaming agent, and a flame retardant were prepared as respective components constituting the polyol composition.

  As the isocyanate composition, polymeric MDI (manufactured by Tosoh Corporation, product name Millionate (registered trademark) MR-200) was prepared.

Examples of bromine-free aromatic polyester polyols include terephthalic acid-based aromatic polyester polyols (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name: MAXIMOL ™ RFK-
505 (hydroxyl value 250 mg · KOH / g)).

  As the bromine-based polyol, the following two types (bromine-based polyol A and bromine-based polyol B) were prepared. As the bromine-based polyol A, an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton (manufactured by Wanka Chemical Co., Ltd., product name FR-130 [a brominated polyol component is 70% by mass, a phosphate ester component ( Liquid mixture containing phosphate ester A) at a ratio of 30% by mass], hydroxyl value 110 mg · KOH / g), and bromine-based polyol B include bromine-containing aliphatic polyether polyol (manufactured by Nippon Solvay Co., Ltd. Name B251 [mixture containing 93.5% by mass of bromine-based polyol component and 6.5% by mass of phosphate ester component (phosphate ester B)], hydroxyl value 330 mg · KOH / g) are prepared. Was.

  As the polyether polyol, a Mannich-based polyether polyol (manufactured by Asahi Glass Co., Ltd., product name WB-620 (hydroxyl value 290 mg · KOH / g)) was prepared.

  As the flame retardant, a solid flame retardant and a liquid flame retardant were prepared. Red phosphorus (manufactured by Rin Kagaku Kogyo Co., Ltd., product name Nova Excel (trademark) 140) was prepared as a solid flame retardant. Further, a phosphoric ester (phosphate ester C) (trade name: TMCPP, manufactured by Daihachi Chemical Industry Co., Ltd.) was prepared as a liquid flame retardant.

  A silicone compound (product name: SH193, manufactured by Dow Corning Toray Co., Ltd.) was prepared as a foam stabilizer.

  Water and a hydrofluoroolefin (manufactured by Chemers Co., Ltd., product name: Opteon (trademark) 1100) were prepared as foaming agents.

  The following three types of catalysts (referred to as catalysts A, B, and C, respectively) were prepared.

Catalyst A: potassium octylate (PERLON, product name PELCAT9540)
Catalyst B: quaternary ammonium salt (TOYOCAT (trademark) -TR20, manufactured by Tosoh Corporation)
Catalyst C: N, N, N ', N ", N" -pentamethyldiethylenetriamine (TOYOCAT-DT, manufactured by Tosoh Corporation)

Examples 1 to 12 and Comparative Examples 1 to 11
The polyol, the solid flame retardant, the liquid flame retardant, the foam stabilizer, the catalyst, and the foaming agent were blended in the amounts shown in Tables 1 and 2 to obtain a polyol composition. The units of the numbers described in the column of the polyol composition in Tables 1 and 2 are parts by mass.

  In addition, the addition amount of the bromine-based polyols A and B shown in the values in Tables 1 and 2 is the amount of bromine excluding the amount of the phosphate component (phosphate esters A and B) contained in the bromine-based polyols A and B. It is the amount of the system polyol component. The amounts of the liquid flame retardants shown in Tables 1 and 2 correspond to the amounts of the phosphate esters A and B contained in the brominated polyols A and B, and the amount of the phosphate esters prepared as the liquid flame retardants. This is the total amount of C added.

  At a volume ratio of isocyanate composition / polyol composition as shown in Tables 1 and 2, the polyol composition and the isocyanate composition were mixed and immediately put into a previously prepared wooden box of 175 mm × 290 mm × 215 mm, The urethane reaction of the polyol composition and the isocyanate composition and the foaming by the foaming agent were advanced to cure the foam, thereby obtaining a rigid polyurethane foam. The units of the numbers described in the column of the isocyanate composition in Tables 1 and 2 are parts by mass. The isocyanate index of a mixture of the polyol composition and the isocyanate composition is as shown in Tables 1 and 2. In addition, the mixing of the polyol composition and the isocyanate composition was performed by a hand mixer.

(Density of rigid polyurethane foam)
The density of the formed rigid polyurethane foam was measured as follows. That is, a test piece was cut out from a rigid polyurethane foam so as to have a size of 100 mm long × 100 mm wide × 100 mm thick, the weight of the test piece was measured, and the density (kg / m ³ ) was calculated. The results are shown in Tables 1 and 2.

(Dimensional stability of rigid polyurethane foam)
The dimensional stability of the formed rigid polyurethane foam was evaluated based on the results of the following volume change confirmation test. The evaluation results are shown in Tables 1 and 2.

(Volume change confirmation test)
A test specimen (initial volume: 1 × 10 ⁶ mm ³ ) was cut out from the formed rigid polyurethane foam to a size of 100 mm long × 100 mm wide × 100 mm thick. The test specimen was exposed to three conditions of a temperature of 70 ° C., a humidity of 95% RH, a temperature of −20 ° C., and a temperature of 100 ° C. for 24 hours, and the volume change rate (%) after the exposure was measured. . The rate of change in volume is specified by dividing the volume (mm ³ ) of the test specimen after exposure by the initial volume. Based on the specified rate of volume change, the dimensional stability was evaluated as follows.

（(Good): The volume change rate is 10% or less.
X (bad): the volume change rate exceeds 10%.

  A good rigid polyurethane foam has a volume change of 10% or less in all three conditions, and a good rigid polyurethane foam has a volume change of more than 10% in any of the three conditions. It cannot be said that.

(Exothermic evaluation test)
A test body was prepared using the formed rigid polyurethane foam, and an exothermic evaluation test was performed. As a test body, a piece cut out from the formed rigid polyurethane foam into a size of 100 mm long × 100 mm wide × 50 mm thick was used. The exothermic test was performed in accordance with the above-mentioned ISO 5660-1, and the heating strength was 50 kW / m ² . The exothermic test was performed in two patterns: when the required time was 10 minutes, and when the required time was 20 minutes. Regarding any of the patterns, the results of the exothermic test were evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.

(Evaluation criteria for exothermic test)
Condition 1: The total amount of heat generated from the start of heating to the elapse of the required time is 8 MJ / m ² or less.
Condition 2: No generation of penetrating cracks or holes is observed even if combustion is continued until the required time has elapsed from the start of heating.
Condition 3: No situation is observed in which the maximum heat generation rate exceeds 200 kW / m ² and continues for 10 seconds or more from the start of heating to the elapse of the required time.

  When the required time was set to 10 minutes for all of Examples 1 to 12, all of Conditions 1 to 3 were satisfied. In particular, in Examples 7 to 10 and 12, not only when the required time was set to 10 minutes, but also when the required time was set to 20 minutes, all of the conditions 1 to 3 were satisfied.

  For Examples 5 and 7 and Examples 9 to 12, the following dispersion confirmation test was performed to determine whether or not the state in which the solid flame retardant was dispersed was maintained after the preparation of the polyol composition.

(Dispersion confirmation test)
After the preparation of the polyol composition, 80 mL of the mixture was poured into a test tube and allowed to stand, and it was checked whether precipitation of the solid flame retardant was visually confirmed with the passage of time. In Example 12, no precipitation was observed until 30 minutes after the start of standing, and the dispersion state was maintained. In Examples 5 and 7 and Examples 9 to 11, no precipitation was observed for 1 hour or more after the start of standing. In this way, the polyol composition and the isocyanate composition are mixed at the site where the heat insulating layer is provided to adjust the mixture, and the mixture is directly sprayed onto a target portion such as a wall surface using a spray gun or the like to form a rigid polyurethane foam. It was confirmed that even when a solid flame retardant was present in the polyol composition, the dispersion state of the solid flame retardant could be maintained for a sufficient time. In particular, according to Examples 5, 7 and Examples 9 to 11, since no precipitation was observed for 1 hour or more after the start of standing, the polyol composition was prepared at a place slightly away from the site where the heat insulating layer was provided. Even if the polyol composition is transferred to the site where the heat insulating layer is provided later, the polyol composition can maintain the dispersed state of the solid flame retardant.

Claims (3)

Polyol composition containing a polyol, a foam stabilizer, a catalyst, a foaming agent and a flame retardant, and a rigid polyurethane foam composed of a reaction product with an isocyanate composition,
The polyol contained in the polyol composition contains a bromine-based polyol and a bromine-free aromatic polyester polyol,
When the addition amount of the polyol is 100 parts by mass, the addition amount of the brominated polyol is 25 parts by mass or more and 70 parts by mass or less,
The rigid polyurethane foam, wherein the bromine-based polyol has an aromatic ring, and has a skeleton in which at least one or more bromine is bonded to the aromatic ring.   The rigid polyurethane foam according to claim 1, wherein the flame retardant contains red phosphorus.   The rigid polyurethane foam according to claim 2, wherein the addition amount of red phosphorus contained in the flame retardant is 17 parts by mass or less when the addition amount of the polyol is 100 parts by mass.