JP2015224265A - Rigid urethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid urethane foam that has a particular foam cell structure in order to achieve fire-retardancy performance of the rigid urethane foam to the utmost extent.SOLUTION: The rigid urethane foam is characterized in that: the density is in the range of 20 to 80 kg/m; halogenated hydrocarbon and flame retardant are contained; the foam cell has shape having a major axis and a minor axis; and the maximum heat generation rate is less than 70 kW/mand the total heat generation amount is less than 10.2 MJ/mthat are measured under the condition of heating intensity of 50 kW/min a flame retardancy test using cone calorimeter in conformity to ISO-5660-1 for the case where the angle formed by the foam cell major axis and the ignition face is made smaller than 45 degrees.

Description

  The present invention relates to a rigid urethane foam excellent in flame retardancy.

  Rigid urethane foam is used for construction, civil engineering-related thermal insulation materials and structural materials, electrical equipment-related thermal insulation materials such as refrigerators, plant and marine thermal insulation materials, vehicle-related cold storage cabinets, etc. It is widely used as a heat insulating material for refrigeration vehicles. Especially for hard urethane foam used in the construction field, there are cases where hard urethane foam is caused by increased fire damage, so the flame retardant standards required for hard urethane foam for building materials are becoming stricter. There is a need for improved flame retardant technology for rigid urethane foam.

  In order to improve the flame retardancy of rigid urethane foam, it is carried out by introducing an isocyanurate ring structure by using an isocyanate trimerization catalyst, or by adding a general-purpose phosphate ester flame retardant (for example, Patent Documents 1 to 3). 4). Further, when a higher degree of flame retardancy is required, it is known that a solid flame retardant such as red phosphorus or ammonium polyphosphate is used as the flame retardant (see, for example, Patent Document 5). . However, the rigid urethane foam obtained by the techniques described in these patent documents may have insufficient flame retardancy. Therefore, it is important to maximize the flame retardant performance of the rigid urethane foam produced.

JP 09-328530 A JP 2001-310925 A JP 2010-53267 A JP 2010-95565 A Japanese Patent Laid-Open No. 2001-200027

  The present invention has been made in view of the background art described above, and an object thereof is to provide a rigid urethane foam having a specific foam cell structure in order to maximize the flame retardancy of the rigid urethane foam. That is.

  As a result of intensive studies to solve the above problems, the present inventors have found that the rigid urethane foam greatly affects the flame retardancy of the rigid urethane foam from which the foamed cell shape can be obtained, thereby completing the present invention. It came to.

  That is, this invention relates to the rigid urethane foam as shown below.

[1] Density is in the range of 20-80 kg / m ³ , containing halogenated hydrocarbon and flame retardant, foam cell shape is a shape having a major axis and a minor axis, and the length of the foam cell In the flame retardancy test using a cone calorimeter conforming to ISO-5660-1 when the angle formed by the shaft and the ignition surface is less than 45 degrees, the maximum measured under the condition of heating strength of 50 kW / m ² A rigid urethane foam having a heat generation rate of less than 70 kW / m ² and a total heat generation amount of less than 10.2 MJ / m ² .

  [2] The halogenated hydrocarbon is “HCFC-123”, “HCFC-141b”, “HCFC-22”, “HCFC-142b” “HFC-134a”, “HFC-245fa”, “HFC-245ca”, The hard as described in [1] above, which is at least one selected from the group consisting of “HFC-365mfc”, “HFC-236ea”, “HFO-1233zd”, and “HFO-1336mzz-Z” Urethane foam.

  [3] The above [1], wherein the polyol and the polyisocyanate are reacted in the presence of a halogenated hydrocarbon-containing blowing agent, a catalyst, and a flame retardant under a condition where the isocyanate index is 200 or more. The method for producing a rigid urethane foam according to [2].

  [4] The method for producing a rigid urethane foam according to the above [3], wherein the catalyst contains a quaternary ammonium salt.

  [5] The method for producing a rigid urethane foam according to the above [4] or [5], wherein the foaming agent contains 2 parts by weight or less of water with respect to 100 parts by weight of polyol.

  The rigid urethane foam of the present invention can exhibit the flame retardancy of the rigid urethane foam to the maximum, and is extremely useful as a heat insulating material or a structural material that requires flame retardancy.

  Hereinafter, the present invention will be described in more detail.

The rigid urethane foam of the present invention is
(1) The density is in the range of 20-80 kg / m ³ ;
(2) containing a halogenated hydrocarbon and a flame retardant,
(3) The foam cell shape is a shape having a major axis and a minor axis, and (4) ISO-5660-1 in the case where the angle formed by the major axis of the foam cell and the ignition surface is smaller than 45 degrees. in the flame retardancy test using compliant cone calorimeter, peak heat rate at which the heating intensity is measured under the condition of 50 kW / ^{m 2} is 70 kW / ^m of less than ^2, and the total calorific value is less than 10.2MJ / ^{m 2} It is characterized by that.

The rigid urethane foam of the present invention has a density in the range of 20 to 80 kg / m ³ . When the density is less than 20 kg / m ³ , the strength of the rigid urethane foam decreases, and when the density exceeds 80 kg / m ³ , the cost as a foamed material is increased, which is not preferable. A preferred density is in the range of 35-60 kg / m ³ .

  The rigid urethane foam of the present invention contains a halogenated hydrocarbon. The halogenated hydrocarbon is used as a foaming agent when producing the rigid urethane foam of the present invention.

  The halogenated hydrocarbons include “HCFC-123”, “HCFC-141b”, “HCFC-22”, “HCFC-142b”, “HFC-134a”, “HFC-245fa”, “HFC-245ca”, “HFC”. -365mfc "," HFC-236ea "," HFO-1233zd ", and" HFO-1336mzz-Z "are preferably at least one selected from the group consisting of.

  The rigid urethane foam of the present invention contains a flame retardant. Although it does not specifically limit as a flame retardant, For example, a flame retardant (liquid flame retardant) liquid at normal temperature, a flame retardant (solid flame retardant) solid at normal temperature, etc. are mentioned.

  Specific examples of liquid flame retardants include reactive flame retardants such as phosphorus-containing polyols such as propoxylated phosphoric acid and propoxylated dibutyl pyrophosphate obtained by addition reaction of phosphoric acid and alkylene oxide; tricresyl Examples thereof include phosphate esters such as phosphate; halogen-containing phosphate esters such as trischloroethyl phosphate and trischloropropyl phosphate.

  Specific examples of the solid flame retardant include dibromopropanol, dibromoneopentyl glycol, tetrabromobisphenol A, 2,4,6-tribromophenol, 2,2 ′, 6,6′-tetrabromobisphenol— Halogen-containing organic compounds such as S, decabromodiphenyl ether, hexabromobenzene, bis (pentabromophenyl) ethane, hexabromocyclododecane; halogenated polymers such as brominated polystyrene, brominated epoxy resin, brominated carbonate resin; Examples include phosphorus alone such as red phosphorus; inorganic compounds such as antimony oxide, magnesium carbonate, calcium carbonate, and aluminum phosphate; Among these, a liquid flame retardant is preferable in terms of dispersibility of the flame retardant. The liquid flame retardant is preferably a halogen-containing phosphate ester, and trischloropropyl phosphate is particularly preferable because it has good stability and high flame retardancy.

  The foamed cell of the rigid urethane foam of the present invention has a shape having a major axis and a minor axis. Although it does not specifically limit as a shape which has a long axis and a short axis, For example, an elliptical shape is mentioned.

The rigid urethane foam of the present invention has a maximum heat generation rate measured under the condition of a heating strength of 50 kW / m ² in a flame retardancy test using a cone calorimeter based on ISO-5660-1 which is a flame retardance index. As for the total calorific value, the rigid polyurethane foam whose angle between the major axis of the foam cell and the ignition surface is smaller than 45 degrees is more rigid than the rigid polyurethane foam whose angle between the major axis of the foam cell and the ignition surface exceeds 45 degrees. And has a feature of showing high flame retardancy. Due to this feature, the flame-retardant rigid urethane foam obtained by the production method of the present invention can be used for various applications. For example, heat insulation and structural materials related to construction, civil engineering, electrical equipment related, heat insulating materials such as freezer, refrigerator, freezer showcase, etc., plant and ship related, LPG, LNG tanker and pipeline heat insulating materials, vehicle related Applications such as cold storage and heat insulation for refrigerated vehicles can be mentioned. The angle formed between the ignition surface and the major axis of the foamed cell is usually less than 45 degrees, preferably 0 to 30 degrees, more preferably 0 to 10 degrees.

The rigid urethane foam of the present invention has an angle formed between the major axis of the foamed cell and the ignition surface of 45 degrees in a flame retardancy test using a cone calorimeter based on ISO-5660-1 which is an index of flame retardancy. when was also small, the maximum heat release rate of heating intensity is measured under the condition of 50 kW / ^{m 2} is less than 70 kW / ^{m 2,} the total calorific value is less than 10.2MJ / ^{m 2.}

  Here, the method for producing the rigid urethane foam of the present invention is not particularly limited. For example, in the presence of a blowing agent containing a halogenated hydrocarbon, a catalyst, and a flame retardant, the isocyanate index is 200 or more. The method of making it react on conditions is mentioned.

  Examples of the polyol include conventionally known polyether polyols, polyester polyols, polymer polyols, and flame retardant polyols such as phosphorus-containing polyols and halogen-containing polyols. These polyols can be used alone or in combination as appropriate.

  The polyether polyol is not particularly limited. For example, a compound having at least two active hydrogen groups (polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, and pentaerythritol, ethylenediamine) And the like, and alkanolamines such as ethanolamine and diethanolamine) are used as starting materials, and are produced by addition reaction of this with alkylene oxides (such as ethylene oxide and propylene oxide) [See, for example, Gunter Oertel, “Polyurethane Handbook” (1985) Hanser Publishers (Germany), p. See method according to 42-53].

  The polyester polyol is not particularly limited, but examples thereof include those obtained from the reaction of dibasic acid and glycol, wastes from the production of nylon, trimethylolpropane, pentaerythritol wastes, and phthalic polyester wastes. And polyester polyols obtained by treating waste products [for example, Keiji Iwata “Polyurethane Resin Handbook” (1987) Nikkan Kogyo Shimbun, p. See description of 117. ].

  The polymer polyol is not particularly limited. For example, a polymer polyol obtained by reacting the polyether polyol with an ethylenically unsaturated monomer (for example, butadiene, acrylonitrile, styrene, etc.) in the presence of a radical polymerization catalyst. A coalesced polyol is mentioned.

  The flame retardant polyol is not particularly limited. For example, a phosphorus-containing polyol obtained by adding alkylene oxide to a phosphoric acid compound, a halogen-containing polyol obtained by ring-opening polymerization of epichlorohydrin or trichlorobutylene oxide, A phenol polyol etc. are mentioned.

  In the production of rigid urethane foam, those having an average hydroxyl value in the range of 100 to 800 mgKOH / g are preferably used. Moreover, in order to improve the flame retardance of a rigid urethane foam, it is preferable to use an aromatic polyester polyol.

  The polyisocyanate is not particularly limited. For example, aliphatic polyisocyanates such as aromatic polyisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetra Aromatic polyisocyanates such as methylxylylene diisocyanate and modified products thereof (for example, carbodiimide modification, allophanate modification, urea modification, burette modification, isocyanurate modification, oxazolidone modification, etc.), isocyanate group-terminated prepolymers, etc. . In order to improve the flame retardancy of the rigid urethane foam obtained, it is preferable to use an aromatic polyisocyanate.

  Specific examples of aromatic polyisocyanates include 2,4- or 2,6-toluene diisocyanate (TDI), crude TDI, diphenylmethane 2,4'- or 4,4'-diisocyanate (MDI), polymethylene polyisocyanate. Examples include phenyl isocyanate (crude MDI).

  Specific examples of the aliphatic polyisocyanate include isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and the like.

  Although it does not specifically limit as a catalyst, For example, a tertiary amine compound, carboxylate, quaternary ammonium salt etc. are mentioned. When excellent flame retardancy is required, carboxylates, quaternary ammonium salts, and mixtures thereof are preferred.

  The tertiary amine compound is not particularly limited. For example, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N , N ′, N ″, N ″ -pentamethyldiethylenetriamine, N, N, N ′, N ″, N ″ -pentamethyl- (3-aminopropyl) ethylenediamine, N, N, N ′, N ″, N ″ — Pentamethyldipropylenetriamine, N, N, N ′, N′-tetramethylguanidine, 1,3,5-tris (N, N-dimethylaminopropyl) hexahydro-S-triazine, 1,8-diazabicyclo [5. 4.0] undecene-7, triethylenediamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N′-dimethylpiperazine, dimethylcycle Hexylamine, N-methylmorpholine, N-ethylmorpholine, bis (2-dimethylaminoethyl) ether, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole Conventionally known compounds such as

  In addition, the carboxylate is not particularly limited, and examples thereof include alkali metal salts and alkaline earth metal salts of carboxylic acids. Here, the carboxylic acid is not particularly limited, but examples thereof include aliphatic mono- and dicarboxylic acids such as acetic acid, propionic acid, 2-ethylhexanoic acid and adipic acid, and aromatic mono-monomers such as benzoic acid and phthalic acid. And conventionally known compounds such as dicarboxylic acids. Moreover, as a metal which should form carboxylate, alkaline earth metals, such as alkali metals, such as lithium, sodium, and potassium, and calcium, magnesium, are mentioned as a suitable example.

  Further, the quaternary ammonium salt is not particularly limited. For example, tetramethylammonium acetate, tetramethylammonium formate, tetramethylammonium 2-ethylhexanoate, tetraethylammonium acetate, trimethylmonoethylammonium Examples include acetate, trimethylmono n-octylammonium acetate, and trimethylmono n-dodecylammonium acetate.

  These catalysts can be used alone or as a mixture of two or more.

  In the present invention, a foaming agent containing a halogen hydrocarbon is used as the foaming agent. Specific examples of the halogenated hydrocarbon blowing agent include those of the HCFC type (for example, “HCFC-123”, “HCFC-141b”, “HCFC-22”, “HCFC-142b”, etc.), HFC type Examples thereof include “HFC-134a”, “HFC-245fa”, “HFC-245ca”, “HFC-365mfc”, “HFC-236ea”, etc., and a mixture of two or more of these. Among these, “HCFC-141b”, “HFC-134a”, “HFC-245fa”, “HFC-365mfc”, and a mixture of two or more thereof are preferable as the blowing agent.

  The foaming agent can be used by mixing the above-mentioned halogen hydrocarbon with other foaming agents as long as the effect is not impaired. Although it does not specifically limit as another foaming agent, For example, a low boiling point hydrocarbon, water, etc. are mentioned. In the present invention, the “low boiling point hydrocarbon” means a hydrocarbon having a boiling point of usually 0 to 50 ° C., and specific examples thereof include propane, butane, pentane, cyclopentane, and mixtures thereof.

  However, from the viewpoint of flame retardancy of the resulting rigid urethane foam, the proportion of halogenated hydrocarbon is preferably 70% by weight or more among all the foaming agents.

  The amount of water used is desirably 2 parts by weight or less with respect to 100 parts by weight of polyol. When the usage-amount of water exceeds 2 weight part with respect to 100 weight part of polyol, since a flame retardance falls, it is unpreferable.

  In the present invention, examples of the flame retardant include the above-described flame retardant that is liquid at room temperature (liquid flame retardant), a flame retardant that is solid at room temperature (solid flame retardant), and the like.

  In the present invention, the isocyanate index is determined by (number of equivalents of isocyanate groups in the isocyanate component per equivalent of active hydrogen groups of all raw materials) × 100.

  In the present invention, other auxiliary agents other than those described above may be included as long as the effects of the present invention are obtained. Examples of such auxiliary agents include foam stabilizers, colorants, anti-aging agents, and other conventionally known additives. The type and amount of these additives may be within the normal usage range of the additive used.

  Examples of the foam stabilizer include conventionally known organosilicon surfactants, and are not particularly limited. Specifically, organosiloxane-polyoxyalkylene copolymers, silicone-grease copolymers, etc. Nonionic surfactants, mixtures thereof and the like are exemplified.

  Although it does not specifically limit as a concrete manufacturing method of the rigid urethane foam of this invention, For example, the polyol which mixed uniformly all the raw materials except polyisocyanate (B) among the raw materials for rigid urethane foam manufacture beforehand A desired flame-retardant rigid urethane foam can be produced by mixing the composition and the isocyanate (B), stirring and stirring rapidly, and then injecting the mixture into an appropriate container or mold to perform foam molding. The specific manufacturing apparatus is not particularly limited as long as these can be uniformly mixed. For example, a low pressure or a low pressure for injection foaming used when manufacturing a small mixer or a general urethane foam is used. A spray-type foaming apparatus, such as a high-pressure foaming machine, a low-pressure or high-pressure foaming machine for slab foaming, a low-pressure or high-pressure foaming machine for continuous lines, or the like can be used.

  The following examples further illustrate the present invention, but the present invention is not limited to these examples. In addition, (pbw) in a table | surface shows the weight part of another agent when a polyol is 100 weight part.

  In the following examples, the measurement method for each measurement item is as follows.

<Reactivity measurement items>
Cream time: The rising start time of the foamed foam was measured visually.

  Gel time: The time required for the reaction to progress to a resinous substance from a liquid substance was measured.

<Core density of foam>
The center part of the foam foamed in a 5 L (liter) mold having an inner size of 25 cm × 25 cm × 8 cm was cut into a size of 20 cm × 20 cm × 4 cm, and the core density was calculated by accurately measuring the size and weight.

<Foam cell shape>
Porous cell structure analysis device (product name: PORE! SCAN, manufactured by Golducke Co., Ltd.) for the ignition surface of the sample cut out from the foam foamed using the mold and the foam cell structure on the surface perpendicular to the major axis of the foam cell It measured using.

<Maximum heat generation rate and total heat generation during foam combustion>
A sample for evaluation of combustion characteristics of 10 cm × 10 cm × 4 cm was cut out from a rigid urethane foam having a size of 20 cm × 20 cm × 4 cm, the core density of which was measured. Surfaces other than the ignition surface (10 cm × 10 cm surface) were wrapped with aluminum foil having a thickness of 25 μm, and set in a sample holder with ceramic wool laid on the bottom. The sample holder on which the test sample was set was placed on a test stand of a cone calorimeter (manufactured by Toyo Seiki Seisakusho) and adjusted so that the distance between the lower part of the heater and the ignition surface was 25 mm. The test was started by heating the heater in advance so that the heating intensity was 50 kW / m ² and sparking the ignition surface with a spark plug. When ignition was confirmed, the spark plug was removed, the heat generation rate and the heat generation amount were measured for 20 minutes from the start of the spark, and the maximum heat generation rate and the total heat generation amount during that time were determined (based on ISO-5660-1).

Example 1 Production of flame retardant rigid urethane foam.
In a 500 mL polyethylene container, 37.6 g of aromatic polyester polyol (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name: Maximol RDK-133, OH value = 317 mgKOH / g), aromatic polyester polyol (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 9.4 g of product name: DK polyol 3810, OH number = 320 mgKOH / g) was added and stirring was started at room temperature. Subsequently, 1.2 g of a 75% by weight aqueous solution of tetramethylammonium acetate as a catalyst, 0.3 g of N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (manufactured by Tosoh Corporation, product name: TOYOCAT-DT) 1.0 g of a silicone-based surfactant (manufactured by Dow Corning Toray, product name: SZ1642) as a foam stabilizer, and tris (2-chloropropyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name) as a flame retardant 51.5 g of TMCPP), 21.5 g of 1,1-dichloro-1-fluoroethane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.3 g of water were added as a blowing agent, and stirring was continued. By adjusting, a polyol composition for producing rigid urethane foam was obtained.

  A mold having an inner dimension of 25 cm × 25 cm × 8 cm, the temperature of which was adjusted to 50 ° C., was placed so that the upper surface was a surface of 25 cm × 8 cm. Next, 169 g of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd., product name: MR-200, NCO content 30.7% by weight) adjusted to a temperature of 20 ° C. as a polyisocyanate is added to the polyol composition, and a laboratory mixer is used. The mixture was stirred and mixed uniformly at 6000 rpm for 5 seconds, and this was poured into a mold to perform foam molding. At this time, the reactivity was measured. The mold was removed after 7 minutes from the time when the mixed raw materials were put into the mold to produce a flame-retardant rigid urethane foam. The core density of the obtained rigid urethane foam was measured. Also, PORE! The shape of the foam cell was measured using SCAN (manufactured by Golducke). Further, the foam was cut so that the surface corresponding to the 25 cm × 25 cm surface of the mold was the ignition surface, and the maximum heat generation rate and the total heat generation amount were measured by a flame retardancy test using a cone calorimeter. These results are also shown in Table 1.

Comparative Example 1
Rigid urethane foam was manufactured by the same method as Example 1 except having carried out the mold installation method at the time of foam molding so that the upper surface may become a surface of 25 cm x 25 cm. The reactivity, foam core density, and maximum heat generation rate in the combustion test were measured in the same manner as in Example 1. These results are also shown in Table 1.

Example 2
In a 500 mL polyethylene container, 40.8 g of aromatic polyester polyol (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name: Maximol RDK-133, OH value = 317 mgKOH / g), aromatic polyester polyol (Daiichi Kogyo Seiyaku, product name) : DK polyol 3810, OH value = 320 mgKOH / g) 10.2 g was added and stirring was started at room temperature. Subsequently, 1.3 g of a 75% by weight aqueous solution of tetramethylammonium acetate as a catalyst, 0.3 g of N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (manufactured by Tosoh Corporation, product name: TOYOCAT-DT) 1.0 g of a silicone-based surfactant (manufactured by Dow Corning Toray, product name: SZ1642) as a foam stabilizer, and tris (2-chloropropyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name) as a flame retardant TMCPP) 56.1 g, HFC-365mfc (made by Nippon Zeon Co., Ltd.) 25.5 g as a foaming agent, and water 0.3 g were added and stirring continued, and the temperature was adjusted to 20 ° C. to produce rigid urethane foam. A polyol composition was obtained.

  A mold having an inner dimension of 25 cm × 25 cm × 8 cm, the temperature of which was adjusted to 50 ° C., was placed so that the upper surface was a surface of 25 cm × 8 cm. Next, 183 g of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd., product name: MR-200, NCO content 30.7% by weight) adjusted to 20 ° C. as a polyisocyanate is added to the polyol composition, and a laboratory mixer is used. The mixture was stirred and mixed uniformly at 6000 rpm for 5 seconds, and this was poured into a mold to perform foam molding. At this time, the reactivity was measured. The mold was removed after 7 minutes from the time when the mixed raw materials were put into the mold to produce a flame-retardant rigid urethane foam. The core density of the obtained rigid urethane foam was measured. Also, PORE! The shape of the foam cell was measured using SCAN (manufactured by Golducke). Further, the foam was cut so that the surface corresponding to the 25 cm × 25 cm surface of the mold was the ignition surface, and the maximum heat generation rate and the total heat generation amount were measured by a flame retardancy test using a cone calorimeter. These results are also shown in Table 1.

Comparative Example 2
Rigid urethane foam was manufactured by the same method as Example 2 except having carried out the mold installation method at the time of foam molding so that the upper surface may become a surface of 25 cm x 25 cm. The reactivity, the foam core density, and the maximum heat generation rate of the combustion test were measured in the same manner as in Example 2. These results are also shown in Table 1.

  As is clear from Table 1, the rigid urethane foam of the present invention exhibited excellent flame retardancy as compared with the corresponding comparative example.

  The rigid urethane foam having a specific foamed cell shape of the present invention exhibits excellent flame retardancy, and heat insulating materials such as architectural, civil engineering related heat insulating materials and structural materials, electric equipment related freezers, refrigerators, freezer showcases, It is useful as a heat insulating material such as a plant or ship-related LPG or LNG tanker, a vehicle-related cold storage, a heat insulating material for a freezer car, or the like.

Claims (5)

The density is in the range of 20 to 80 kg / m ^3, the composition contains a halogenated hydrocarbon and a flame retardant, the foam cell shape is a shape having a major axis and a minor axis, and the major axis and ignition of the foam cell. In the flame retardancy test using a cone calorimeter in accordance with ISO-5660-1 when the angle formed by the surface is smaller than 45 degrees, the maximum heat generation rate measured under the condition where the heating intensity is 50 kW / m ² is A rigid urethane foam characterized by being less than 70 kW / m ² and having a total calorific value of less than 10.2 MJ / m ² . Halogenated hydrocarbons are "HCFC-123", "HCFC-141b", "HCFC-22", "HCFC-142b", "HFC-134a", "HFC-245fa", "HFC-245ca", "HFC- The rigid urethane foam according to claim 1, which is at least one member selected from the group consisting of “365 mfc”, “HFC-236ea”, “HFO-1233zd”, and “HFO-1336mzz-Z”. The rigid urethane according to claim 1 or 2, wherein the polyol and the polyisocyanate are reacted under the condition of an isocyanate index of 200 or more in the presence of a blowing agent containing a halogenated hydrocarbon and a catalyst. Form manufacturing method. The method for producing a rigid urethane foam according to claim 3, wherein the catalyst contains a quaternary ammonium salt. The method for producing a rigid urethane foam according to claim 3 or 4, wherein the foaming agent contains 2 parts by weight or less of water based on 100 parts by weight of polyol.