JP7164972B2 - rigid polyurethane foam - Google Patents

Description

The present invention relates to rigid polyurethane foams.

From the viewpoint of energy saving, various buildings such as concrete buildings are generally heat-insulated inside to provide a heat-insulating layer. For example, in the case of reinforced concrete buildings such as condominiums, a heat insulating layer is provided on the indoor side walls of the building. Generally, as the heat insulating layer, a foam material having heat insulating performance such as rigid polyurethane foam, glass wool, or the like is used. When rigid polyurethane foam is used, it can be formed by spraying a raw material composition of rigid polyurethane foam onto 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 mixed at the construction site of the building. The mixture is sprayed onto a predetermined position inside the building with a spray gun or the like to carry out a step of foaming rigid polyurethane foam, thereby forming a heat insulating layer made of rigid polyurethane foam.

However, when a rigid polyurethane foam is sprayed as a heat insulating layer, the rigid polyurethane foam may ignite in the event of fire caused by static electricity generated during construction work.

Therefore, Patent Document 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.

WO2014/112394

The red phosphorus required in Patent Document 1 is solid. For this reason, when the flame-retardant urethane resin composition is prepared at the site where the heat insulating layer is to be provided and the rigid polyurethane foam is applied, there is a need to disperse red phosphorus sufficiently and quickly in the flame-retardant urethane resin composition. important. For this reason, in Patent Document 1, when adjusting a flame-retardant urethane resin composition at the site where a heat insulating layer is provided, mechanical equipment is provided to sufficiently and quickly disperse red phosphorus in the flame-retardant urethane resin composition. It was difficult to form rigid polyurethane foam with uniform flame retardancy at low cost by spraying. In addition, if the red phosphorus is poorly dispersed in the flame-retardant urethane resin composition, the red phosphorus in the resulting rigid polyurethane foam becomes nonuniform, causing 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 dwelling. Poor appearance of rigid polyurethane foam, especially when rigid polyurethane foam is used as a heat insulating layer, not only causes non-uniformity in the heat insulating properties of the heat insulating layer, but also leads to the occurrence of gaps, which can lead to fires. This is an important problem because there is a risk that the interior will burn through the gap.

It is an object of the present invention to provide a rigid polyurethane foam which is excellent in external appearance and which exhibits more easily and uniformly high flame retardancy even when the rigid polyurethane foam is formed by spraying at the 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 blowing agent and a flame retardant (but not containing a polyol) and an isocyanate composition. There is
The polyol contained in the polyol composition includes a brominated polyol and a bromine-free aromatic polyester polyol,
When the amount of polyol added is 100 parts by mass, the amount of brominated polyol added is 25 parts by mass or more and 70 parts by mass or less,
The brominated polyol has an aromatic ring and has a skeleton in which at least one or more bromines are bonded to the aromatic ring,
The flame retardant is one or more selected from red phosphorus, metal hydroxide, zinc borate, ammonium polyphosphate, antimony oxide, phosphoric acid ester, and halogenated phosphoric acid ester;
In an exothermic test conducted at a heating intensity of 50 kW/m ² in accordance with ISO 5660-1, all of the following conditions 1 to 4 for noncombustible materials are satisfied,
Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m 2 ^or less.
Below.
Condition 2: Cracks and holes that penetrate even if combustion is continued until the required time has elapsed from the start of heating
Occurrence is not recognized.
Condition 3: The maximum heat generation rate is 200 kW/m ² from the start of heating until the required time has passed.
A state that continues for more than 10 seconds in the state of exceeding is not permitted.
Condition 4: The requested time is 20 minutes.
Alternatively, it satisfies all of the following conditions 1 to 3 and 5 for being a quasi-noncombustible material.
Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m 2 ^or less.
Below.
Condition 2: Cracks and holes that penetrate even if combustion is continued until the required time has elapsed from the start of heating
Occurrence is not recognized.
Condition 3: The maximum heat generation rate is 200 kW/m ² from the start of heating until the required time has passed.
A state that continues for more than 10 seconds in the state of exceeding is not permitted.
Condition 5: The requested time is 10 minutes.
A rigid polyurethane foam characterized by
(2) The rigid polyurethane foam according to (1) above, wherein the flame retardant contains red phosphorus.
(3) The rigid polyurethane foam according to (2) above, wherein the amount of red phosphorus added in the flame retardant is 17 parts by mass or less when the amount of polyol added is 100 parts by mass. .

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

[Rigid polyurethane foam]
The present invention is a rigid polyurethane foam. Rigid polyurethane foams are composed of the reactants of a polyol composition and an isocyanate composition. Also, 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 noncombustible material or a quasi-noncombustible material.

Conditions for a rigid polyurethane foam to be a noncombustible material or a quasi-noncombustible material are to satisfy the following conditions.

(Conditions for noncombustible material)
The conditions for rigid polyurethane foam to be a noncombustible material ^are the following four conditions (conditions It is to satisfy all of conditions 1 to 4).

Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m ² or less.
Condition 2: Even if combustion is continued from the start of heating until the required time elapses, no penetrating cracks or holes are observed.
Condition 3: A state in which the maximum heat generation rate exceeds 200 kW/m ² and continues for 10 seconds or longer from the start of heating until the required time has elapsed is not observed.
Condition 4: The requested time is 20 minutes.

(Conditions for semi-incombustible material)
Regarding the conditions for the rigid polyurethane foam to be a quasi-noncombustible material, the conditions for being a noncombustible material are the same as those for being a noncombustible material, except that the required time is 10 minutes for condition 4 in the above conditions for being a noncombustible material. Same conditions (same for conditions 1 to 3).

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

(polyol)
Aromatic polyester polyols and brominated polyols are used as polyols.

(Aromatic polyester polyol)
Aromatic polyester polyols include aromatic polyester polyols obtained from polyhydric carboxylic acids and polyhydric alcohols through normal esterification reactions, and aromatic polyesters obtained by transesterification of polyester resins, etc. with polyhydric alcohols. polyols. Examples of polyvalent carboxylic acids include aromatic polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, and trimellitic acid, and anhydrides thereof. The above can be used in combination as appropriate. On the other hand, polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, bisphenol A and the like, and these may be used alone or in combination of two. The above can be used in combination as appropriate. Among 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 bromine-free, that is, does not contain bromine in the molecular skeleton of the polyol.

(Addition amount of aromatic polyester polyol)
The amount of the aromatic polyester polyol added is preferably in the range of 30 parts by mass or more and 75 parts by mass or less when the total amount of polyols contained in the polyol composition is 100 parts by mass. When the total amount of polyols contained in the polyol composition is 100 parts by mass, if the amount of the aromatic polyester polyol added is less than 30 parts by mass, the resulting rigid polyurethane foam will be uneven and the compressive strength of the foam will be low. If the addition amount of the aromatic polyester polyol exceeds 75 parts by mass, the content of the brominated polyol, which will be described later, decreases, making it difficult to obtain quasi-noncombustibility for the rigid polyurethane foam.

(Brominated polyol)
The brominated polyol has an aromatic ring and has a skeleton in which at least one or more bromines are bonded to the aromatic ring, and bromine-containing polyester polyols and bromine-containing polyether polyols can be mentioned. 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-described polyhydric alcohol can be used.

Examples of bromine-containing polyether polyols include those obtained by addition polymerization of one or more of bromine-containing polyhydric alcohols such as tetrabromobisphenol A and alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide. Available. When a bromine-containing polyether polyol is used in the present invention, it is particularly preferred to use an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton.

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

(Addition amount of brominated polyol)
The amount of brominated polyol to be added is in the range of 25 parts by mass or more and 70 parts by mass or less when the total amount of polyols contained in the polyol composition is 100 parts by mass. When the total amount of polyols contained in the polyol composition is 100 parts by mass, the addition amount of the brominated polyol is 25 parts by mass or more, so that flame retardancy can be improved without using a large amount of flame retardant. When the addition amount of the brominated polyol is 70 parts by mass or less, it is possible to effectively prevent the risk of shrinkage after the rigid polyurethane foam is formed, and the appearance is excellent. A rigid polyurethane foam can be formed.

(Other polyols)
Polyols other than aromatic polyester polyols and brominated polyols may be included as long as they do not impair the effects of the present invention.

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

(foam stabilizer)
Examples of foam stabilizers include conventionally used silicone compounds and fluorine compounds.

The amount of the foam stabilizer added 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 polyols contained in the polyol composition is 100 parts by mass.

(catalyst)
As the catalyst, conventionally used amine catalysts, metal catalysts, and the like can be used. Examples of amine catalysts 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-isobutyl-2-methylimidazole and the like can be used. Examples of metal catalysts that can be used include stannus octoate; dibutyltin dilaurate; lead octylate; potassium salts such as potassium acetate and potassium octylate; 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 two or more of them may be used in appropriate combination.
In particular, a trimerization catalyst is selected for trimerization by reacting the isocyanate groups contained in the isocyanate compound. Trimerization catalysts promote the formation of isocyanurate rings.

(Trimerization catalyst)
Examples of trimerization catalysts include nitrogen-containing aromatic compounds, alkali metal carboxylates, and quaternary ammonium salts.

(Amount of catalyst added)
The amount of the catalyst to be 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 polyols contained in the polyol composition is 100 parts by mass. If the amount of the catalyst is less than 1 part by weight, the curing reaction of the foam will be too slow to form a foam, and if it exceeds 10 parts by weight, the curing reaction will be too fast. It causes dents and non-uniform physical properties. Considering this point, the amount of catalyst added is more preferably 1.5 parts by mass or more and 8 parts by mass or less.

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

When water is selected as the foaming agent, the amount of water added is in the range of 0.5 parts by mass or more and 6 parts by mass or less when the total amount of polyols contained in the polyol composition is 100 parts by mass. preferable. The density of the rigid polyurethane foam obtained is adjusted by the amount of water added. The amount of polyurethane foam raw material used increases, resulting in poor yield. If it exceeds 6 parts by mass, the density is too low and the foam tends to shrink. Considering this point, the amount of water to be added is more preferably 1 part by mass or more and 4 parts by mass or less.

The addition 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 polyols contained in the polyol composition is 100 parts by mass. The density of the rigid polyurethane foam to be obtained is adjusted by the amount of the blowing agent added, and the desired density can be easily obtained within this range. Considering this point, the amount of the foaming agent to be added is more preferably 25 parts by mass or more and 45 parts by mass or less.

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

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

Examples of solid flame retardants include red phosphorus, metal hydroxides, especially aluminum hydroxide, magnesium hydroxide, zinc borate and ammonium polyphosphate, and antimony oxide. Red phosphorus is preferably selected as the solid flame retardant in consideration of the fact that it promotes effective char (carbonized layer) formation during combustion and exhibits an excellent effect of preventing the spread of fire.

(Amount of solid flame retardant added)
The amount of the solid flame retardant added is preferably in the range of 17 parts by mass or less when the total amount of polyols contained in the polyol composition is 100 parts by mass. When the amount of the solid flame retardant added is within this range, a rigid polyurethane foam having a flame retardancy of semi-incombustible or higher can be obtained. If the amount of the solid flame retardant added is excessively large, the solid flame retardant will precipitate in the polyol composition, making it difficult to form a rigid polyurethane foam that exhibits uniform flame retardancy. The following are more preferable. Furthermore, the addition amount of the solid flame retardant is preferably 5 parts by mass or more and 12 parts by mass or less because a nonflammable material can be easily obtained.

(liquid flame retardant)
A liquid flame retardant is a flame retardant that is liquid under an atmosphere of atmospheric pressure and normal temperature (25°C).

Examples of liquid flame retardants include phosphoric acid esters such as trimethyl phosphate and triethyl phosphate, and halogenated phosphoric acid esters such as trischloroethyl phosphate and trischloropropyl phosphate.

(Addition amount of liquid flame retardant)
The amount of the liquid flame retardant 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 polyols contained in the polyol composition is 100 parts by mass. When the amount of the liquid flame retardant added is within such a range, it is possible to impart flame retardancy and obtain a rigid polyurethane foam that does not inhibit skeleton formation and does not easily shrink. Considering this point, the amount of the liquid flame retardant to be added is more preferably 60 parts by mass or more and 100 parts by mass or less.

(other additives)
In addition to the polyol, foam stabilizer, catalyst, foaming agent and flame retardant, other additives may be added to the polyol composition, if necessary. Other additives include plasticizers, fillers, antioxidants, defoamers, compatibilizers, colorants, stabilizers, UV absorbers, and other additives commonly used in the production of rigid polyurethane foams. I can give The amount of other additives added 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 crosslinking agents include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, tetramethylene ether glycol, glycerin, pentaerythritol, trimethylolpropane, monoethanolamine, diethanolamine, isopropanolamine, amino Alcohols such as ethylethanolamine, sucrose, sorbitol and glucose can be used. Among these, tri- or more functional ones are particularly preferred.

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

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

More specifically, isocyanate compounds to be reacted with polyol include diphenylmethane diisocyanate, polymeric MDI (crude MDI), 2,4-tolylene diisocyanate (2,4-TDI), 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]
A rigid polyurethane foam can be formed, for example, as follows. First, a polyol composition and an isocyanate composition are separately obtained. For example, the polyol composition is obtained by blending various components constituting the polyol composition such as polyol, foam stabilizer, catalyst, foaming agent and flame retardant. The isocyanate composition is obtained by blending various constituent components.

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 the site where the heat insulating layer is provided (spraying step). The reaction (urethanization reaction) between the polyol and the isocyanate compound is initiated 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 sprayed portions are cured to form a rigid polyurethane foam. In this way, a layer of rigid polyurethane foam is formed on a predetermined surface such as a wall surface, and this layer forms a heat insulating layer. The heat insulating layer made of rigid polyurethane foam has high flame retardancy because the polyols used in forming the heat insulating layer are aromatic polyester polyol and specific brominated polyol.

In addition, when red phosphorus, which is a solid flame retardant, is used as the flame retardant of the polyol composition, the brominated polyol contained in the polyol composition can provide a high flame retardant even if the amount of the solid flame retardant added is reduced. Combustibility can be obtained, and sedimentation of the solid flame retardant is suppressed. In addition, since sedimentation of the solid flame retardant is suppressed, a state in which the solid flame retardant is more effectively dispersed can be achieved both when preparing the polyol composition and when mixing the polyol composition and the isocyanate composition. It is easy to form a state in which the solid flame retardant is uniformly dispersed in the rigid polyurethane foam. As a heat insulating layer made of rigid polyurethane foam, a layer uniformly having high flame retardancy can be formed.

The present invention will now be further described using examples.

An isocyanate composition was provided. Also, 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 (trademark) MR-200) was prepared.

As the bromine-free aromatic polyester polyol, terephthalic acid-based aromatic polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name Maximol (trademark) RFK-
505 (hydroxyl value 250 mg·KOH/g)) was prepared.

As brominated polyols, the following two types (brominated polyol A and brominated polyol B) were prepared. As the brominated polyol A, an aromatic bromine-containing polyether polyol having a tetrabromobisphenol A skeleton (manufactured by Wanhua Chemical Co., Ltd., product name FR-130 [70% by mass of brominated polyol component, phosphate ester component ( Mixture containing phosphate ester A) at a ratio of 30% by mass], hydroxyl value 110 mg KOH / g), Bromine-containing polyol B as bromine-containing aliphatic polyether polyol (Japan Solvay Co., Ltd., product Name B251 [mixture containing 93.5% by mass of brominated polyol component and 6.5% by mass of phosphate ester component (phosphate ester B)], hydroxyl value 330 mg KOH / g) is prepared. rice field.

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

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

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

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

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

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

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

The addition amounts of the brominated polyols A and B shown in the values in Tables 1 and 2 are the amounts of the phosphate ester components (phosphate esters A and B) contained in the brominated polyols A and B. is the amount of the system polyol component. The amount of the liquid flame retardant added shown in Tables 1 and 2 is the amount corresponding to the phosphate esters A and B contained in the brominated polyols A and B, and the phosphate ester prepared as the liquid flame retardant. It is the total amount of C added.

The polyol composition and the isocyanate composition are mixed at the volume ratio of the isocyanate composition/polyol composition as shown in Tables 1 and 2, and immediately put into a previously prepared wooden box of 175 mm × 290 mm × 215 mm, Urethane reaction between the polyol composition and the isocyanate composition and foaming with a foaming agent were allowed to proceed and cured to obtain a rigid polyurethane foam. The unit of the figures described in the isocyanate composition column in Tables 1 and 2 is parts by mass. Tables 1 and 2 show the isocyanate index in the mixture of the polyol composition and the isocyanate composition. In addition, the mixing of the polyol composition and the isocyanate composition was carried out using a hand mixer.

(Density of rigid polyurethane foam)
Density of the formed rigid polyurethane foam was performed as follows. Specifically, a test piece having dimensions of 100 mm long×100 mm wide×100 mm thick was cut out from a rigid polyurethane foam, the weight of the test piece was measured, and the density (kg/m ³ ) was calculated. Tables 1 and 2 show the results.

(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. Tables 1 and 2 show the evaluation results.

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

○ (Good): The volume change rate is 10% or less.
x (defective): Volume change rate exceeds 10%.

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

(Pyrogenic evaluation test)
A test piece was prepared using the formed rigid polyurethane foam, and an exothermic evaluation test was conducted. As a test piece, a piece having a size of 100 mm long×100 mm wide×50 mm thick was cut out from the formed rigid polyurethane foam and used. The exothermic test was conducted in accordance with ISO5660-1 mentioned above, and the heating intensity was set at 50 kW/m ² . The exothermic test was conducted in two patterns, one with a required time of 10 minutes and the other with a required time of 20 minutes. The results of the exothermic test for any pattern were evaluated according to the following evaluation criteria. Tables 1 and 2 show the results.

(Evaluation Criteria for Pyrogenicity Test)
Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m ² or less.
Condition 2: Even if combustion is continued from the start of heating until the required time elapses, no penetrating cracks or holes are observed.
Condition 3: From the start of heating to the elapse of the required time, a situation in which the maximum heat generation rate exceeds 200 kW/m ² for 10 seconds or more is not observed.

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

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

(Dispersion Confirmation Test)
After the preparation of the polyol composition, 80 mL of the polyol composition was poured into a test tube, allowed to stand, and whether or not precipitation of the solid flame retardant was visually confirmed over time was carried out. Regarding Example 12, no precipitation was observed until 30 minutes after the start of standing, and the dispersed state was maintained. For Examples 5, 7 and 9 to 11, no precipitation was observed for 1 hour or longer after the start of standing. As a result, the polyol composition and the isocyanate composition are mixed at the site where the heat insulating layer is to be provided, the mixture is adjusted, and the mixture is sprayed directly onto the target area such as a wall surface using a spray gun or the like to form a rigid polyurethane foam. In, it was confirmed that even if the solid flame retardant is present in the polyol composition, the solid flame retardant can be maintained in a dispersed state for a sufficient period of time. In particular, according to Examples 5, 7 and 9 to 11, no precipitation was observed for 1 hour or more after the start of standing, so the polyol composition was prepared at a location slightly away from the site where the heat insulating layer was provided. Even if the polyol composition is transported to the site where the heat insulating layer is to be provided later, the polyol composition can maintain the dispersed state of the solid flame retardant.

Claims (3)

A rigid polyurethane foam comprising a reaction product of a polyol composition containing a polyol, a foam stabilizer, a catalyst, a blowing agent and a flame retardant (but not containing a polyol) and an isocyanate composition,
The polyol contained in the polyol composition includes a brominated polyol and a bromine-free aromatic polyester polyol,
When the amount of polyol added is 100 parts by mass, the amount of brominated polyol added is 25 parts by mass or more and 70 parts by mass or less,
The brominated polyol has an aromatic ring and has a skeleton in which at least one or more bromines are bonded to the aromatic ring,
The flame retardant is one or more selected from red phosphorus, metal hydroxide, zinc borate, ammonium polyphosphate, antimony oxide, phosphoric acid ester, and halogenated phosphoric acid ester;
In an exothermic test conducted at a heating intensity of 50 kW/m ² in accordance with ISO 5660-1, all of the following conditions 1 to 4 for noncombustible materials are satisfied,
Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m 2 ^or less.
Below.
Condition 2: Cracks and holes that penetrate even if combustion is continued until the required time has elapsed from the start of heating
Occurrence is not recognized.
Condition 3: The maximum heat generation rate is 200 kW/m ² from the start of heating until the required time has passed.
A state that continues for more than 10 seconds in the state of exceeding is not permitted.
Condition 4: The requested time is 20 minutes.
Alternatively, it satisfies all of the following conditions 1 to 3 and 5 for being a quasi-noncombustible material.
Condition 1: The total amount of heat generated from the start of heating until the required time elapses is 8 MJ/m 2 ^or less.
Below.
Condition 2: Cracks and holes that penetrate even if combustion is continued until the required time has elapsed from the start of heating
Occurrence is not recognized.
Condition 3: The maximum heat generation rate is 200 kW/m ² from the start of heating until the required time has passed.
A state that continues for more than 10 seconds in the state of exceeding is not permitted.
Condition 5: The requested time is 10 minutes.

A rigid polyurethane foam characterized by: 2. The rigid polyurethane foam of Claim 1, wherein the flame retardant includes red phosphorus. 3. The rigid polyurethane foam according to claim 2, wherein the amount of red phosphorus added in the flame retardant is 17 parts by mass or less when the amount of polyol added is 100 parts by mass.