Resin composition and foam for phenolic foam

Abstract

This resin composition for a phenol foam contains: (A) a resol-type phenol resin; (B) an acidic curing agent; (C) a foaming agent; (D) urea; and (E) an aliphatic epoxy compound. This resin composition for a phenol foam can further contain, for example, (F) a solid phosphorous flame retardant; and (G) a plasticizer. The aliphatic epoxy compound (E) is preferably a compound having a glycidyl ether at at least one molecule terminus.

Description

[Technical Field]

[0001] The present invention relates to a resin composition for phenolic foam that provides a phenolic resin foam having closed cells, wherein the difference in the percentage of closed cells between the surface layer and the deeper interior is small, exhibits excellent heat insulation properties, and is less susceptible to water absorption when in contact with water. [Background technology]

[0002] Traditionally, phenolic resin foam, also known as phenol foam, has been widely used in the construction industry, for example, as insulation material, due to its excellent heat resistance and flame retardancy. Such phenolic resin foam is manufactured by foaming and curing a composition containing phenolic resin, a blowing agent, a curing agent, etc. The resulting phenolic resin foam usually has closed cells, and these closed cells contain gas derived from the blowing agent.

[0003] The following technologies are known for phenolic resin foams and compositions used in their formation. Patent Document 1 discloses a phenolic resin foam characterized by mixing and foaming a resol-type phenolic resin with an acidic catalyst containing resorcinols as a curing accelerator in the presence of a foaming agent and a foam stabilizer. Patent Document 2 discloses a foaming resol-type phenolic resin composition comprising (A) a resol-type phenolic resin, (B) an acid curing agent, (C) a foaming agent, (D) a foam stabilizer, and (E) a modifier, wherein as component (E), a mono and / or polyglycidyl ether compound having a weight-average molecular weight of 200 to 3000 and an epoxy equivalent in the range of 150 to 2500 is contained in an amount of 0.2 to 20 parts by weight per 100 parts by weight of component (A), and a phenolic resin foam obtained by foaming and curing this composition. Furthermore, Patent Document 3 discloses a foaming resol-type phenolic resin molding material comprising a liquid resol-type phenolic resin, a foaming agent, a foam stabilizer, and an acid curing agent, characterized in that it further contains an epoxy resin compound as an additive, and a phenolic resin foam obtained by foaming and curing this molding material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 59-124940 [Patent Document 2] Japanese Patent Publication No. 2004-176008 [Patent Document 3] Japanese Patent Publication No. 2011-16919 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Conventional phenolic resin foams obtained using compositions containing resol-type phenolic resin, acid curing agents, and foaming agents sometimes exhibited unstable performance due to a large difference between the closed-cell ratio in the surface layer and the closed-cell ratio in the deeper interior (center) of the foam. Furthermore, some conventionally known phenolic resin foams were prone to water absorption upon contact. For example, in the construction field, when phenolic resin foams were used in contact with metal components in humid environments or environments exposed to rainwater, the acid curing agent could be extracted by water, causing corrosion of the metal components. Moreover, when flame retardants were added to the raw material composition to impart flame retardancy to the foam, the water absorption of the foam sometimes increased. Additionally, when manufacturing phenolic resin foams using molds, the curing reaction of the phenolic resin is based on dehydration condensation, which sometimes resulted in the foam becoming too small compared to the mold size as curing progressed. The present invention aims to provide a resin composition for phenolic foam, which is a foam having closed cells, in which the difference in the percentage of closed cells between the surface layer and the deeper interior is small, the initial thermal conductivity can be reduced, it has excellent heat insulation properties, it is less likely to absorb water when in contact with water, and it gives a phenolic resin foam of a desired size while keeping the shrinkage rate during manufacturing low. [Means for solving the problem]

[0006] The present invention is described below. [1] A resin composition for phenol foam containing (A) a resol-type phenolic resin, (B) an acid curing agent, (C) a foaming agent, (D) urea, and (E) an aliphatic epoxy compound. [2] The resin composition for phenol foam according to [1] above, wherein the aliphatic epoxy compound (E) has at least one glycidyl ether group at one molecular terminus. [3] The resin composition for phenol foam according to [1] or [2] above, wherein the aliphatic epoxy compound (E) is an aliphatic polyol polyglycidyl ether compound. [4] A resin composition for phenol foam according to any one of the above [1] to [3], wherein the epoxy equivalent of the aliphatic epoxy compound (E) is 100 to 320 g / eq. [5] The resin composition for phenol foam according to any one of the above [1] to [4], wherein the viscosity (at 25°C) of the aliphatic epoxy compound (E) is 5 to 250,000 mPa·s. [6] A resin composition for phenol foam according to any one of the above [1] to [5], further comprising a solid phosphorus-based flame retardant. [7] The resin composition for phenol foam according to [6] above, wherein the phosphorus-based flame retardant contains red phosphorus. [8] A resin composition for phenol foam according to any one of the above [1] to [7], further comprising a plasticizer. [9] The resin composition for phenol foam according to [8] above, comprising the plasticizer polyester polyol.

[10] The resin composition for phenol foam according to [8] above, comprising an organophosphate ester as the plasticizer.

[11] A foam obtained by foaming a resin composition for phenol foam described in any one of the above items [1] to

[10] .

[12] The foam described in

[11] above, wherein the average percentage of closed cells in the surface layer and the center of the foam is 80% or more. [Effects of the Invention]

[0007] By using the resin composition for phenolic foam of the present invention, it is possible to efficiently produce phenolic resin foams with a desired size and a low shrinkage rate, while having closed cells with a small difference in the percentage of closed cells between the surface layer and the deeper interior. Furthermore, it is possible to produce phenolic resin foams with low thermal conductivity, excellent heat insulation properties, and low water absorption when in contact with water. If the resin composition for phenol foam of the present invention further contains a solid phosphorus-based flame retardant, it is possible to produce a phenol resin foam that is flame-retardant while maintaining its property of being less susceptible to water absorption when in contact with water. If the resin composition for phenol foam of the present invention further contains a plasticizer, a phenol resin foam having uniform foam cells can be produced. The phenolic resin foam of the present invention has closed cells with a small difference in the ratio of closed cells between the surface layer and the deeper interior, and has low thermal conductivity, making it suitable as an insulating material. Furthermore, when used in environments that may be humid or exposed to rainwater, the acid curing agent is less likely to be extracted by water, so in applications such as in the construction field where the foam comes into contact with metal components, a corrosion suppression effect on metal components can be expected. [Modes for carrying out the invention]

[0008] The present invention will be described below. The matters shown here are exemplary and for exemplarily explaining embodiments of the present invention, and are described for the purpose of providing an explanation that can most effectively and easily understand the principles and conceptual features of the present invention. In this regard, it is necessary for a fundamental understanding of the present invention, and it is not intended to show the constitutive details of the present invention more than a certain extent, and this description makes it clear to those skilled in the art how some forms of the present invention are actually embodied.

[0009] 1. Resin Composition for Phenolic Foam The resin composition for phenolic foam of the present invention (hereinafter sometimes simply referred to as "the resin composition of the present invention") is (A) A resol type phenolic resin (hereinafter also referred to as "component (A)"), (B) An acid curing agent (hereinafter also referred to as "component (B)"), (C) A foaming agent (hereinafter also referred to as "component (C)"), (D) Urea (hereinafter also referred to as "component (D)"), and (E) An aliphatic epoxy compound (hereinafter also referred to as "component (E)") contain. The resin composition of the present invention can further contain other components (described later) as necessary.

[0010] 1-1. Component (A) Component (A) is usually a resol type phenolic resin obtained by reacting phenols such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, resorcinol or modified products thereof with aldehydes such as formaldehyde, paraformaldehyde, furfural, acetaldehyde, etc. in the presence of an alkali catalyst such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc. The usage ratio of phenols and aldehydes is not particularly limited, but in terms of molar ratio, it is usually about 1.0:1.5 to 1.0:3.0, preferably 1.0:1.8 to 1.0:2.5. Component (A) contained in the resin composition of the present invention may be only one kind or two or more kinds.

[0011] The viscosity and molecular weight of component (A) are not particularly limited. The viscosity (at 25°C) measured by a Brookfield viscometer (in accordance with JIS K 7117-1) is preferably 2000 to 100000 mPa·s, more preferably 3000 to 80000 mPa·s, and even more preferably 5000 to 30000 mPa·s. The weight-average molecular weight Mw measured by gel permeation chromatography is preferably 400 to 3000, more preferably 700 to 2000. A weight-average molecular weight of 400 or more makes it easier to further improve the compressive strength and further reduce the thermal conductivity of the resulting foam. A weight-average molecular weight Mw of 3000 or less makes the resin composition of the present invention less viscous, resulting in good handling properties and making it easier to obtain the desired foaming ratio.

[0012] 1-2. Ingredient (B) The acid curing agent of component (B) is a component that promotes the curing reaction of component (A), and can be an inorganic acid such as phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphate, tripolyphosphate, polyphosphate, hydrochloric acid, sulfuric acid, or borofluoric acid; an aromatic sulfonic acid such as benzenesulfonic acid, ethylbenzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, phenolsulfonic acid, cresolsulfonic acid, or naphthalenesulfonic acid; or an aliphatic sulfonic acid such as methanesulfonic acid or trifluoromethanesulfonic acid. Component (B) in the resin composition of the present invention may be only one type or two or more types. It is preferable that component (B) according to the present invention contains an organic acid. Among these acid curing agents, phenolsulfonic acid, toluenesulfonic acid, xylenesulfonic acid, and naphthalenesulfonic acid are particularly preferred for use in the production of phenolic foam because they can achieve an appropriate curing speed, resulting in a better balance between the curing of the resol-type phenolic resin and foaming by the foaming agent, thereby achieving a desirable foamed structure. In particular, in the present invention, the combined use of p-toluenesulfonic acid and xylenesulfonic acid is recommended. In terms of mass, it is desirable that the amount of p-toluenesulfonic acid used is greater than the amount of xylenesulfonic acid used. Specifically, the mass ratio of p-toluenesulfonic acid to xylenesulfonic acid is favorably adopted within the range of 51:49 to 95:5.

[0013] From the viewpoint of the curability of the composition during foam production, the content of component (B) in the resin composition of the present invention is preferably 1 to 50 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 7 to 25 parts by mass, when the content of component (A) is 100 parts by mass.

[0014] 1-3. Component (C) The foaming agent of component (C) is a component that efficiently foams component (A) while forming closed cells, and can be, for example, hydrocarbons, halogenated hydrocarbons, ether compounds, nitrogen, argon, carbon dioxide, water, air, etc. The resin composition of the present invention may contain only one type of component (C) or two or more types.

[0015] As the hydrocarbon, aliphatic or alicyclic saturated hydrocarbons or unsaturated hydrocarbons can be used. Of these, aliphatic or alicyclic saturated hydrocarbons are preferred. The number of carbon atoms in the hydrocarbon is preferably 3 to 7, and specific compounds include propane, butane, pentane, isopentane, hexane, isohexane, neohexane, heptane, isoheptane, cyclopentane, and the like.

[0016] As the halogenated hydrocarbon, halogenated hydrocarbons of aliphatic or alicyclic saturated hydrocarbons or unsaturated hydrocarbons can be used. This compound may be one in which all of the hydrogen atoms constituting the hydrocarbon are replaced with halogen atoms, or it may be a compound in which some of the hydrogen atoms constituting the hydrocarbon remain while the remaining hydrogen atoms are replaced with halogen atoms. The halogen atoms can be fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, but preferably fluorine atoms and chlorine atoms, and particularly preferably chlorine atoms.

[0017] The halogenated hydrocarbon is preferably a halogenated hydrocarbon, more preferably a chlorinated aliphatic saturated hydrocarbon. Examples include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, and isopentyl chloride. Of these, propyl chloride and isopropyl chloride are preferred, and isopropyl chloride is particularly preferred.

[0018] In the case of halides of unsaturated hydrocarbons, preferably, compounds are obtained in which at least one hydrogen atom in an unsaturated hydrocarbon having 2 to 6 carbon atoms is substituted with a fluorine atom and / or a chlorine atom. Specific examples of such compounds include tetrafluoropropene, fluorochloropropene, trifluoromonochloropropene, pentafluoropropene, fluorochlorobutene, and hexafluorobutene.

[0019] Specifically, hydrofluoroolefins (HFOs), which are halides of such unsaturated hydrocarbons, include, for example, pentafluoropropenes such as 1,2,3,3,3-pentafluoropropene (HFO1225ye), tetrafluoropropenes such as 1,3,3,3-tetrafluoropropene (HFO1234ze), 2,3,3,3-tetrafluoropropene (HFO1234yf), and 3,3,3-trifluoropropene (HFO1243). Examples include trifluoropropenes such as zf), tetrafluorobutene isomers (HFO1354), pentafluorobutene isomers (HFO1345), hexafluorobutene isomers (HFO1336) such as 1,1,1,4,4,4-hexafluoro-2-butene (HFO1336mzz), heptafluorobutene isomers (HFO1327), heptafluoropentene isomers (HFO1447), octafluoropentene isomers (HFO1438), and nonafluoropentene isomers (HFO1429). Examples of hydrochlorofluoroolefins (HCFOs) include 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), dichlorotrifluoropropene (HCFO1223), 1-chloro-2,3,3-trifluoropropene (HCFO-1233yd), 1-chloro-1,3,3-trifluoropropene (HCFO-1233zb), 2-chloro-1,3,3-trifluoropropene (HCFO-1233xe), 2-chloro-2,2,3-trifluoropropene (HCFO-1233xc), 3-chloro-1,2,3-trifluoropropene (HCFO-1233ye), and 3-chloro-1,1,2-trifluoropropene (HCFO-1233yc).

[0020] In the present invention, component (C) preferably consists of multiple components, and a specific combination may be an aliphatic or alicyclic saturated hydrocarbon and a halogenated saturated hydrocarbon. Particularly preferred is a combination of an aliphatic saturated hydrocarbon and a chlorinated saturated hydrocarbon that contains a hydrogen atom. As such a combination of two blowing agents, a combination of isopentane and isopropyl chloride is recommended, and this can more advantageously achieve the objective of the present invention. In this case, the mass ratio is not particularly limited, but when the total of the two is taken as 100% by mass, it is usually 5 to 25% by mass and 75 to 95% by mass, respectively.

[0021] The content of component (C) in the resin composition of the present invention is preferably 1 to 30 parts by mass, more preferably 3 to 28 parts by mass, and even more preferably 5 to 25 parts by mass, when the content of component (A) is 100 parts by mass, from the viewpoint of foaming properties and curing properties of component (A) during foam production.

[0022] 1-4.Component (D) Component (D), urea, can effectively reduce the initial thermal conductivity of the resulting foam, reduce the odor of the foam, and, when used in combination with component (E), reduces the difference in the percentage of closed cells between the surface layer and the deeper interior of the foam, thereby reducing water absorption. The content of component (D) in the resin composition of the present invention is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, when the content of component (A) is 100 parts by mass.

[0023] 1-5. Component (E) The aliphatic epoxy compound of component (E) is a compound having a linear and / or branched carbon chain and an epoxy group, and is a component that causes a foam with a low shrinkage rate and a desired size to form, and reduces the water absorption of the foam. Component (E) in the resin composition of the present invention may be only one type or two or more types.

[0024] The carbon chains constituting component (E) typically form hydrocarbon groups, or the hydrogen atoms contained in the hydrocarbon groups form functional groups (e.g., hydroxyl groups) containing at least one atom selected from oxygen, nitrogen, sulfur, and halogen atoms, or substituted hydrocarbon groups in which such atoms are substituted. Furthermore, the number of epoxy groups contained in component (E) is not particularly limited, preferably one or more, more preferably two or more, and even more preferably two to six.

[0025] In the present invention, component (E) is preferably a compound in which the epoxy group constitutes a glycidyl ether group represented by the following formula (1), in order to obtain a sufficient effect of reducing the water absorption of the foam. [ka]

[0026] The number of glycidyl ether groups contained in component (E) is not particularly limited, but is preferably one or more, more preferably two or more, and even more preferably two to six.

[0027] The compound containing the glycidyl ether group represented by the above formula (1) is not particularly limited, but is preferably an aliphatic polyol polyglycidyl ether compound. This aliphatic polyol polyglycidyl ether compound may have a hydroxyl group. Furthermore, the aliphatic polyol polyglycidyl ether compound is preferably an aliphatic polyhydric alcohol polyglycidyl ether.

[0028] Aliphatic polyol polyglycidyl ether compounds include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolethane polyglycidyl ether, trimethylolpropane polyglycidyl ether, ditrimethyl Examples include tyrolpropane polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, hydrogenated bisphenol A type diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, hydroquinone diglycidyl ether, 2,6-hexanetriol polyglycidyl ether, 1,4-butanediol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. Furthermore, the aliphatic polyol polyglycidyl ether compound may be either a monomer or a polymer, but using a monomer results in low water absorption upon contact with water, and a well-balanced foam with a small difference in the closed-cell ratio between the surface layer and the deeper interior.

[0029] In the present invention, the epoxy equivalent of component (E) is preferably 100 to 320 g / eq, more preferably 100 to 300 g / eq, and even more preferably 100 to 280 g / eq, from the viewpoint of producing a good foam and reducing the water absorption of the resulting foam. The epoxy equivalent is a value measured in accordance with JIS K 7236:2009.

[0030] In the present invention, the viscosity of component (E) is not particularly limited, but the viscosity measured by a Brookfield viscometer (temperature: 25°C) is preferably 5 to 25,000 mPa·s, more preferably 10 to 22,000 mPa·s, even more preferably 10 to 6,000 mPa·s, and most preferably 10 to 900 mPa·s, from the viewpoint of the handling properties of the resin composition and the effect of reducing the water absorption of the resulting foam. As described above, the preferred upper limit of viscosity for component (A) is 100,000 mPa·s, and the preferred upper limit of viscosity for component (E) is 25,000 mPa·s, indicating that component (E) is a viscosity reducing agent. In this respect, the fluidity of the resin composition of the present invention is good, and the moldability of the foam can be improved.

[0031] From the viewpoint of reducing the water absorption effect of the foam, the content of component (E) in the resin composition of the present invention is preferably 1 to 20 parts by mass, more preferably 2 to 18 parts by mass, and even more preferably 3 to 15 parts by mass, when the content of component (A) is 100 parts by mass.

[0032] The resin composition of the present invention, since it requires the above-mentioned components (A), (B), (C), (D), and (E), can efficiently produce a phenolic resin foam with a desired size and low shrinkage, which has a small difference in the closed-cell ratio between the surface layer and the deeper interior. Furthermore, it can produce a phenolic resin foam with low thermal conductivity, excellent heat insulation properties, and low water absorption when in contact with water. In addition, in a preferred embodiment, a foam with a dimensional change rate of preferably 2.5% or less, more preferably 2.4% or less, can be produced by the method described in the [Examples] below.

[0033] 1-6. Other ingredients The resin composition of the present invention may contain other components in addition to the above-mentioned essential components (A), (B), (C), (D), and (E). Examples of other components include flame retardants, plasticizers, foam stabilizers, corrosion inhibitors, and inorganic fillers.

[0034] The flame retardant may be in solid or liquid form, and examples include phosphorus-containing compounds, triazole compounds, triazine compounds, cyclic monoureides, cyclic diureides, amidine compounds, tetrazole compounds, borates, stanates, molybdates, tungstates, metal oxides (such as antimony oxide), metal hydroxides, metal sulfides, polyphenylene sulfide resins, polyphenylene oxide resins, polycarbonate resins, polyarylate resins, aromatic amide resins, aralkyl resins, aromatic vinyl resins, and the like. When the resin composition of the present invention contains a flame retardant, it may contain only one type of flame retardant or two or more types.

[0035] The flame retardant is preferably a solid phosphorus-containing compound (hereinafter also referred to as "component (F)"). This component (F) may be either an inorganic material (hereinafter referred to as "inorganic phosphorus-based flame retardant") or an organic material (hereinafter referred to as "organophosphorus-based flame retardant"). Generally, when a foam is manufactured using a resin composition containing a flame retardant, the desired flame retardancy can be obtained, but the foam may have high water absorption or a high rate of dimensional change. However, when component (F) is included as the flame retardant, the resin composition of the present invention contains components (D) and (E), so it is possible to manufacture a phenolic resin foam that has flame retardancy while maintaining a low rate of dimensional change and low water absorption when in contact with water.

[0036] Examples of inorganic phosphorus-based flame retardants include red phosphorus, (poly)phosphates, and phosphazenes. Note that "(poly)phosphate" refers to both monophosphates and polyphosphates.

[0037] Examples of (poly)phosphates include salts of non-condensed or condensed (ortho)phosphoric acids such as orthophosphoric acid, phosphorous acid, hypophosphoric acid, polyphosphoric acid (metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, etc.), and polyphosphoric acid (metaphosphoric acid, pyrophosphoric acid, etc.) with at least one metal or compound thereof selected from metals of groups IA to IVB of the periodic table, ammonia, aliphatic amines, and aromatic amines. Examples of metals of groups IA to IVB of the periodic table include lithium, sodium, calcium, barium, iron(II), iron(III), and aluminum. Examples of aliphatic amines include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, and piperazine. Examples of aromatic amines include pyridine, triazine, melamine, and ammonium.

[0038] Specific examples of monophosphates include ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; sodium salts such as monosodium phosphate, disodium phosphate, trisodium phosphate, monosodium phosphite, disodium phosphite, and sodium hypophosphite; potassium salts such as monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, and potassium hypophosphite; lithium salts such as monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphite, dilithium phosphite, and lithium hypophosphite; barium salts such as barium dihydrogen phosphate, barium hydrogen phosphate, tribarium phosphate, and barium hypophosphite; magnesium salts such as magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, and magnesium hypophosphite; and calcium salts such as calcium dihydrogen phosphate, calcium hydrogen phosphate, tricalcium phosphate, and calcium hypophosphite. Examples of polyphosphates include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium polyphosphate amide, and aluminum polyphosphate.

[0039] Examples of organophosphorus flame retardants include phosphate esters, phosphate ester amides, phosphonitrile compounds, organophosphonic acid compounds (phosphonic acid esters, phosphonic acid metal salts, etc.), organophosphinic acid compounds (phosphinic acid metal salts, etc.), phosphine oxides, resorcinol phosphates, hydroquinone phosphates, biphenol phosphates, bisphenol phosphates, and the like.

[0040] In the present invention, component (F) preferably contains an inorganic phosphorus-based flame retardant, more preferably contains red phosphorus or (poly)phosphate, and is particularly preferred to contain red phosphorus because it provides high flame retardancy.

[0041] When producing a resin composition containing red phosphorus, it is preferable to use red phosphorus having a coating layer on its surface, as this provides a resin composition with excellent handling properties and good dispersibility of the red phosphorus. The constituent material of the coating layer may be either an inorganic compound or an organic compound. Examples of inorganic compounds include metal oxides or metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zinc hydroxide, titanium hydroxide, aluminum oxide, magnesium oxide, zinc oxide, and titanium oxide. Examples of organic compounds include thermosetting resins such as phenolic resins, furan resins, and xylene-formaldehyde resins.

[0042] The average particle size of component (F), as measured by laser diffraction and scattering, is preferably about 1 to 100 μm, more preferably about 5 to 50 μm. If the particle size of component (F) is too small, uniform dispersion in the resin composition may be difficult. On the other hand, if the particle size of component (F) is too large, a uniform dispersion effect in the resin composition may not be obtained.

[0043] If the resin composition of the present invention contains a flame retardant, the amount of the flame retardant is preferably 0.3 to 30 parts by mass, more preferably 1 to 25 parts by mass, and even more preferably 2 to 20 parts by mass, when the amount of component (A) is 100 parts by mass.

[0044] If the resin composition of the present invention contains red phosphorus as a flame retardant, it may also contain other flame retardants besides red phosphorus. For example, other solid phosphorus-based flame retardants, liquid phosphorus-based flame retardants, or flame retardants that do not contain phosphorus can be used. In this case, the content of the other flame retardant is preferably 0.5 to 1000 parts by mass, more preferably 1 to 300 parts by mass, and even more preferably 3 to 100 parts by mass, when the content of red phosphorus is 100 parts by mass.

[0045] Examples of plasticizers include polyester polyols, polyethylene glycols, aromatic carboxylic acid esters, and organic phosphate esters. When the resin composition of the present invention contains a plasticizer, the flame retardant may be one type or two or more types. In a resin composition containing a plasticizer, the plasticizer penetrates between the molecules of component (A), weakening the intermolecular forces of component (A) and making each molecular chain more mobile. This gives flexibility to the cured resin of component (A), and the water absorption rate of the foam can be further reduced by a synergistic effect.

[0046] The plasticizer is preferably a polyester polyol and an organic phosphate ester, and particularly preferably a polyester polyol. Polyester polyols have a structure containing ester bonds and hydroxyl groups, which are excellent in hydrophilicity and surface activity. Therefore, they have good compatibility with hydrophilic component (A), and a uniform resin composition can be obtained. Furthermore, when a resin composition containing polyester polyols is used, the uneven distribution of bubbles is suppressed, and a foam with homogeneous bubbles can be obtained. Polyester polyols and organic phosphate esters may be used individually as plasticizers, but using them in combination makes it possible to produce a phenolic resin foam that is even less water-absorbent when in contact with water.

[0047] Polyester polyols are compounds having multiple hydroxyl groups, obtained by esterifying a polyol with a polycarboxylic acid. The starting materials, polyol and polycarboxylic acid, may be aliphatic, alicyclic, or aromatic compounds, but aromatic compounds are more preferred. In the present invention, the polyester polyol is preferably a polyester polyol obtained by esterifying a polyol having 2 to 5 hydroxyl groups with a polycarboxylic acid having 2 to 4 carboxyl groups, and particularly preferably a polyester polyol represented by the following general formula (2) obtained by esterifying a polyol having 2 hydroxyl groups (hereinafter referred to as "diol") with a polycarboxylic acid having 2 carboxyl groups (hereinafter referred to as "dicarboxylic acid"). [ka] (In the formula, A is a residue obtained by removing the carboxyl group from a dicarboxylic acid, and R 1 (where n is a residue obtained by removing the hydroxyl group from a diol, and n is an integer greater than or equal to 1.)

[0048] The diol may be an aliphatic diol, an alicyclic diol, or an aromatic diol, and may have other functional groups or ether or ester bonds in its molecule.

[0049] Aliphatic diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2,2-dimethyl-1,3-propanediol (nempentyl glycol), 2,2-diethyl-1,3-propanediol, 2,2-dipropyl-1,3-propanediol, 2,2-diisopropyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, 2,2-diisobutyl-1,3-propanediol, and 2-methyl-2-dodecyl Examples include alkanediols such as 1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2-propyl-2-pentyl-1,3-propanediol; oxyalkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol; and polyester diols, which are reaction products (ring-opening compounds) of lactones such as β-butyrolactone, γ-butyrolactone, and δ-valerolactone with oxyalkylene glycols such as ethylene glycol, diethylene glycol, and triethylene glycol.

[0050] Examples of alicyclic diols include cyclopentane-1,2-diol, cyclopentane-1,2-dimethanol, cyclohexane-1,2-diol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-diol, cyclohexane-1,3-dimethanol, cyclohensan-1,4-diol, cyclohexane-1,4-dimethanol, and 2,5-norbornanediol. Examples of aromatic diols include benzene-1,2-dimethanol, benzene-1,3-dimethanol, benzene-1,4-dimethanol, catechol, resorcinol, hydroquinone, and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).

[0051] In the present invention, the diol is preferably an aliphatic diol and an alicyclic diol, and particularly preferably ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-dimethanol, and cyclohexanedimethanol.

[0052] The dicarboxylic acid may be an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid, or an aromatic dicarboxylic acid, and may have other functional groups in its molecule.

[0053] Examples of aliphatic dicarboxylic acids include adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Examples of alicyclic dicarboxylic acids include cyclohexane-1,2-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, and cyclohexane-1,4-dicarboxylic acid. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid.

[0054] In the present invention, the dicarboxylic acid is preferably an aromatic dicarboxylic acid, and particularly preferably phthalic acid, isophthalic acid, and terephthalic acid.

[0055] The weight-average molecular weight of the polyester polyol is preferably 200 to 10,000, more preferably 200 to 5,000, because this imparts flexibility to the cell walls of the resulting foam and suppresses degradation over time.

[0056] The hydroxyl value of polyester polyols is not particularly limited, but is usually between 10 and 500 mg KOH / g.

[0057] When the resin composition of the present invention contains a polyester polyol, the amount of the polyol is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, based on 100 parts by mass of component (A), in order to impart flexibility to the cell walls and obtain a foam having homogeneous cells.

[0058] Organophosphate esters are preferably compounds that are liquid at room temperature, such as compounds represented by the following general formula (3). O=P-(OR 2 )3(3) (In the formula, each R 2 These may be the same or different groups, and are hydrocarbon groups or halogenated hydrocarbon groups.

[0059] Examples of organic phosphate esters represented by the above general formula (3) include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, tri-2-ethylhexyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate, tris(2-chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, and the like.

[0060] When the resin composition of the present invention contains an organic phosphate ester, the amount thereof is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 8 parts by mass, based on the content of component (A) being 100 parts by mass, in order to impart low water absorption to the resulting foam. Furthermore, since some of the preferred organic phosphate esters mentioned above are conventionally known as flame retardants for resins, using a resin composition containing such organic phosphate esters makes it possible to produce flame-retardant foams. In addition, using organic phosphate esters with a viscosity of 100 mPa·s or less at 25°C can reduce the viscosity of the resin composition and improve its fluidity.

[0061] Examples of foam stabilizers include castor oil or its alkylene oxide adducts, alkylphenol ethylene oxide adducts, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene glycol, dimethylpolysiloxane-polyoxyalkylene copolymers, dimethylpolysiloxane-polyoxyethylene-polyoxypropylene copolymers, and polyoxyethylene sorbitan fatty acid esters.

[0062] Examples of corrosion inhibitors include nitrogen-containing cross-linked cyclic compounds such as quinuclidine and hexamethylenetetramine (hexamine).

[0063] As inorganic fillers, fine particles consisting of calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, calcium silicate, magnesium hydroxide, aluminum hydroxide, mica, talc, bentonite, zeolite, silica gel, aluminum oxide, titanium dioxide, antimony oxide, etc. can be used.

[0064] 1-7. Method for producing resin compositions for phenolic foams The resin composition of the present invention can be produced by mixing the above components (A), (B), (C), (D), and (E) together with other components which may be used in combination as needed.

[0065] 2. Foam The foam of the present invention is obtained by foaming and curing the resin composition of the present invention described above. The foam of the present invention typically has closed cells and a density of 10 to 150 kg / m³. 3 It is a foam. If the density is low, the amount of material can be reduced, making the foam lighter and improving handling, but the mechanical strength will decrease, so the density is preferably 20 to 80 kg / m³. 3 More preferably 27-70 kg / m 3 More preferably 29-60 kg / m 3 Particularly preferred is 30-50 kg / m 3 That is the case.

[0066] The closed cell ratio (conforming to ASTM D2856) of the foam of the present invention is preferably 85% or more, more preferably 86% or more, at the center of the foam. Further, the average of the closed cell ratio of the surface layer portion of the foam and the closed cell ratio of the deeper interior (center portion) thereof is 80% or more, preferably 85% or more. Since the foam of the present invention is formed from a resin composition containing specific components, the difference in the closed cell ratio measured between the surface layer portion of the foam and the deeper interior (center portion) thereof is small. For example, when a block-shaped foam with a size of 50 mm or more in thickness is machined, and the closed cell ratio in the surface layer portion from the surface to a depth of 7 mm and the closed cell ratio in the deeper interior (center portion) are measured, the difference is preferably 15% or less, more preferably 12% or less.

[0067] The thermal conductivity of the foam of the present invention (conforming to ISO 11561 Annex B, measurement temperature: 20 °C) is preferably 0.0200 W / (m·K) or less, more preferably 0.0197 W / (m·K) or less. A foam having such a low thermal conductivity is suitable for use as a heat insulating material, a packaging material, and the like.

[0068] When the water absorption amount of the foam of the present invention when brought into contact with water is measured by a method conforming to JIS K 9511, it is preferably 5.0 g / 100 cm 2 or less, more preferably 4.5 g / 100 cm 2 or less. When a foam having such properties is used in an environment where it can become humid or in an environment exposed to rainwater, the acid curing agent is less likely to be extracted by water. Therefore, in applications in the construction field where the foam is brought into contact with a metal member, for example, corrosion of the metal member can be suppressed.

[0069] A foam produced using a resin composition containing a flame retardant is excellent in flame retardancy, and the oxygen index measured by a method conforming to JIS K 7201-2 is preferably 28 or more, more preferably 30 or more. Incidentally, the "oxygen index" means the minimum oxygen concentration (volume %) required for a material to sustain combustion.

[0070] The method for producing the foam of the present invention can be appropriately selected depending on the application, etc., and is not particularly limited. For example, conventionally known methods such as those described below can be applied, and if necessary, cutting or other processing can be performed to obtain a foam member of the desired shape and size. (1) A molding method in which a resin composition is poured onto an endless conveyor belt, foamed, and cured. (2) A method of filling a resin composition in a spot manner and partially foaming and curing it. (3) A method of foaming and curing a resin composition by placing it in a mold and pressurizing it. (4) A method for forming a foam block by filling a resin composition into a predetermined large space and allowing it to foam and harden. (5) A method of filling, foaming, and curing a resin composition while pressurizing it into a cavity.

[0071] The manufacturing conditions for the foam include a temperature of preferably 40°C to 90°C, more preferably 50°C to 80°C. The heating time is appropriately selected depending on the size of the foam, but is usually 5 to 30 minutes.

[0072] By utilizing the foam manufacturing method of the present invention, the resin composition of the present invention can be foamed and cured in contact with or near another component to produce a composite in which the foam and the other component are bonded together. As the other component, articles such as sheets, plates, rods, fibers, or deformed forms thereof, made of inorganic materials, organic materials, or composite materials containing these can be used. [Examples]

[0073] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0074] 1. Raw materials for manufacturing the composition The raw materials for the phenolic foam resin compositions used in the examples and comparative examples are shown below.

[0075] 1-1. Resol-type phenolic resins Phenolic resins A-1 and A-2 obtained by the following method were used.

[0076] (Method for manufacturing phenol resin A-1) In a three-necked reaction flask equipped with a refluxer, thermometer, and stirrer, 1600 parts by mass of phenol, 2282 parts by mass of 47% formalin, and 41.6 parts by mass of 50% sodium hydroxide aqueous solution were charged and reacted at 80°C for 70 minutes. Next, the reaction solution was cooled to 40°C, neutralized by adding 50% by mass of p-toluenesulfonic acid aqueous solution, and then dehydrated and concentrated under reduced pressure and heating conditions until the moisture content was 9% by mass, thereby obtaining a liquid resol-type phenol resin. The viscosity of the obtained phenol resin A-1 was measured at 25°C using a Brookfield viscometer in accordance with JIS K 7117-1 and was found to be 9000 mPa·s.

[0077] (Method for manufacturing phenol resin A-2) In a three-necked reaction flask equipped with a refluxer, thermometer, and stirrer, 1600 parts by mass of phenol, 2282 parts by mass of 47% formalin, and 41.6 parts by mass of 50% sodium hydroxide aqueous solution were charged and reacted at 80°C for 90 minutes. Next, the reaction solution was cooled to 40°C, neutralized by adding 50% by mass of p-toluenesulfonic acid aqueous solution, and then dehydrated and concentrated under reduced pressure and heating conditions until the moisture content was 12% by mass, thereby obtaining a liquid resol-type phenol resin. The viscosity of the obtained phenol resin A-2 was measured under the same conditions as above and was found to be 10000 mPa·s.

[0078] 1-2. Hardener A mixture of p-toluenesulfonic acid and xylenesulfonic acid in a mass ratio of 2:1 was used as a curing agent.

[0079] 1-3. Foaming agent Isopropyl chloride and isopentane were mixed in a mass ratio of 85:15 and used as a foaming agent.

[0080] 1-4.Urea

[0081] 1-5. Epoxy Compounds The following commercially available products (aliphatic epoxy compounds or aromatic epoxy resins) were used. E-1: ADEKA Trimethylolpropane Triglycidyl Ether "ADEKA ED-505" (product name) Number of functional groups: 3, epoxy equivalent: 150g / eq, viscosity: 150mPa·s (25℃) E-2: ADEKA's neopentyl glycol diglycidyl ether "ADEKAglycirol ED-523T" (product name) Number of functional groups: 2, epoxy equivalent: 140g / eq, viscosity: 15mPa·s (25℃) E-3: ADEKA Polypropylene Glycol Diglycidyl Ether "ADEKA glycirol ED-506" (product name) Number of functional groups: 2, epoxy equivalent: 300g / eq, viscosity: 60mPa·s (25℃) E-4: Sorbitol polyglycidyl ether "Denacol EX-614B" (product name) manufactured by Nagase ChemteX Corporation. Number of functional groups: 4, epoxy equivalent: 173g / eq, viscosity: 5000mPa·s (25℃) E-5: Sorbitol polyglycidyl ether "Denacol EX-614" (product name) manufactured by Nagase ChemteX Corporation. Epoxy equivalent: 167g / eq, viscosity: 21200mPa·s (25℃) E-6: Bisphenol A type epoxy resin "jER825" (product name) manufactured by Mitsubishi Chemical Corporation. Number of functional groups: 2, Epoxy equivalent: 175 g / eq, Viscosity: 5500 mPa·s (25℃) E-7: ADEKA Corporation's bisphenol F type epoxy resin "ADEKA Resin EP4901" (product name) Number of functional groups: 2, epoxy equivalent: 170g / eq, viscosity: 3500mPa·s (25℃)

[0082] 1-6. Solid Flame Retardants F-1: Red phosphorus manufactured by Phosphorus Chemical Industry Co., Ltd., "Nova Excel 140" (product name), average particle size: 25-35 μm, surface coated. F-2: Zinc borate F-3: Tetrabromobisphenol A

[0083] 1-7. Plasticizers G-1: A polyester polyol obtained by reacting phthalic acid and diethylene glycol in a molar ratio of 1:2 was used. G-2: Tris(chloropropyl) phosphate "TMCPP" (product name), manufactured by Daihachi Chemical Industry Co., Ltd., viscosity: 60 mPa·s (25℃) G-3: Triethyl phosphate "TEP" (product name), manufactured by Daihachi Chemical Industry Co., Ltd., viscosity: 1.6 mPa·s (25℃)

[0084] 2. Manufacturing and evaluation of resin compositions for phenolic foams A resin composition for phenolic foam was manufactured using the above raw materials. Subsequently, the resin composition was heated to produce a phenolic resin foam, and the following various evaluations were performed. (1) Water absorption The "water absorption capacity" was measured in accordance with JIS K 9511. The unit is g / 100cm. 2 That is the case. (2) Closed cell ratio The foam was cut to produce two test specimens: T1 (size: 7mm x 25mm x 25mm), consisting of the surface layer up to a depth of 7mm; and T2 (size: 25mm x 25mm x 25mm, cut 12.5mm above and below the centerline of the foam), prepared from a deeper interior. The closed-cell ratio was measured for each specimen according to ASTM D2856. The unit is %. (3) Dimensional change rate To evaluate the dimensional change of phenolic resin foam during molding, the dimensions of the obtained foam were measured in accordance with JIS A 9511, and the ratio of the shrinkage length to the molding mold dimensions (300 mm × 300 mm × 50 mm) was calculated as a percentage using the following formula. Specifically, for the width direction of the foam, the length of the line connecting the centers of two opposite sides was measured at two points. For the thickness direction, the thickness of each of the four sides of the foam was measured at the center. After calculating the dimensional change rate for each of these, the average of the calculated dimensional change rates for the measured width and thickness was used as the dimensional change rate. The unit is %. Dimensional change rate = [(mold dimensions) - (foam dimensions)] ÷ (mold dimensions) × 100 (4) Initial thermal conductivity In accordance with the "heat flow meter method" specified in JIS A 1412-2 (1999), a phenolic resin foam sample (200 mm × 200 mm × 50 mm) that had been left at 70°C for 4 days was used as the measurement sample with the thermal conductivity measuring device "HC-074 304" manufactured by Eiko Seiki Co., Ltd. The temperature of the low-temperature plate was set to 10°C and the temperature of the high-temperature plate to 30°C, and the thermal conductivity was measured. The measured value was defined as the "initial conductivity". (5) Oxygen Index To evaluate flame retardancy, the oxygen index was measured in accordance with "Plastics - Test method for flammability by oxygen index - Part 2: Test at room temperature" as specified in JIS K 7201-2. (6) Uniformity of the cells in the foam After cutting the foam parallel to its thickness, ten panelists visually inspected the internal cross-section in a 23°C atmosphere and evaluated the uniformity of the cells according to the following criteria. The quality was then ranked based on the average level. A level of 1 indicates better cell uniformity. 1: Uniform cells are observed with no uneven areas whatsoever. 2: Slightly non-uniform cells are observed, but this does not pose a practical problem. 3: Clearly non-uniform cells are observed. 4: A very large number of clearly non-uniform cells are observed.

[0085] Example 1 A liquid resin composition for phenol foam (hereinafter referred to as "resin composition S-1") was prepared by mixing 100 parts by mass of phenol resin A-1, 3 parts by mass of foam stabilizer (castor oil ethylene oxide adduct (22 moles added)), 16 parts by mass of curing agent, 8 parts by mass of foaming agent, 5 parts by mass of urea, and 3 parts by mass of epoxy compound E-1 (see Table 1). Next, the obtained resin composition S-1 was placed in a mold (300mm x 300mm x 50mm) that had been preheated to 70°C to 75°C, and the mold containing the composition was placed in a heating furnace. Then, it was foamed and cured at 70°C for 10 minutes and the mold was removed. Further curing by heating at 70°C for 12 hours resulted in a resin with closed cells and a density of 33 to 35 kg / m³. 3 A phenolic resin foam (hereinafter referred to as "Foam H-1") was obtained. Various evaluations were performed on the obtained Foam H-1 (see Table 1).

[0086] Examples 2-20 Except for the types and amounts of raw materials used as shown in Tables 1 and 2, the same procedure as in Example 1 was followed to produce liquid resin compositions for phenol foam (hereinafter referred to as "resin compositions S-2 to S-20"). Subsequently, phenol resin foams (hereinafter referred to as "foams H-2 to H-20") were produced in the same manner as in Example 1, and various evaluations were performed (see Tables 1 and 2).

[0087] Comparative Examples 1-10 Except for the types and amounts of raw materials used as shown in Table 3, the same procedure as in Example 1 was followed to produce liquid phenol foam resin compositions (hereinafter referred to as "resin compositions SS-1 to SS-10"). Subsequently, phenol resin foams (hereinafter referred to as "foams HH-1 to HH-10") were produced in the same manner as in Example 1, and various evaluations were performed (see Table 3).

[0088] [Table 1]

[0089] [Table 2]

[0090] [Table 3]

[0091] From Tables 1 to 3, the following can be seen. Comparative Examples 1 and 2 are examples of compositions containing aromatic epoxy resins instead of aliphatic epoxy compounds. In Comparative Example 1, the difference in the percentage of closed cells between the surface layer and the deeper interior of the resulting foam HH-1 was large, at over 15%. In Comparative Example 2, the percentage of closed cells in the center of the resulting foam HH-2 was low, at less than 75%. Comparative Examples 3-5, 7, 9, and 10 are examples of compositions that do not contain epoxy compounds, and the water absorption of the resulting foam was 5.0 g / 100 cm. 2 The amount was more than [amount]. Furthermore, Comparative Examples 6 and 8 were examples of compositions that did not contain urea, and the closed-cell ratio in both the surface layer and deeper interior of the resulting foam was low, less than 80%, and the water absorption was 5.0 g / 100 cm. 2 The number was much higher than that. On the other hand, Examples 1 to 20 are examples of compositions of the present invention, and the water absorption capacity of the obtained foams H-1 to H-20 was 5.0 g / 100 cm. 2 The closed-cell ratio in both the surface layer and the deeper interior was 80% or higher, and the difference in the closed-cell ratio between the two was small, less than 12%. Examples 11 and 12 both used resin compositions to which 10 parts by mass of red phosphorus were added to each of the resin compositions of Examples 2 and 5. The water absorption of the resulting foams H-11 and H-12 was slightly higher than that of foams H-2 and H-5, but still 3.0 g / 100 cm 2The water absorption was less than [value missing]. Even when a solid flame retardant was used, the water absorption did not increase. Examples 15, 17, 18, and 20 were examples in which a plasticizer was added to the resin composition of Example 2, and the water absorption of the resulting foam was less than that of foam H-2. Also, Examples 16 and 19 were examples in which a plasticizer was added to the resin composition of Example 5, and the water absorption of the resulting foam was less than that of foam H-5. [Industrial applicability]

[0092] The resin composition for phenolic foam of the present invention is suitable for forming phenolic resin foams having low water absorption and a high closed-cell ratio. The resulting phenolic resin foam can be suitably used, for example, in the construction field, when it is installed in contact with metal members in environments that may be humid or exposed to rainwater.

Claims

1. (A) Resol-type phenolic resin, (B) Acid hardening agent, (C) Foaming agent, (D) urea, (E) Aliphatic epoxy compounds and Flame retardant A resin composition for phenolic foam containing the following:

2. The resin composition for phenol foam according to claim 1, wherein the aliphatic epoxy compound (E) has at least one glycidyl ether group at its molecular end.

3. The resin composition for phenol foam according to claim 1 or 2, wherein the aliphatic epoxy compound (E) is an aliphatic polyol polyglycidyl ether compound.

4. The resin composition for phenol foam according to any one of claims 1 to 3, wherein the epoxy equivalent of the aliphatic epoxy compound (E) is 100 to 320 g / eq.

5. The resin composition for phenol foam according to any one of claims 1 to 4, wherein the viscosity (at 25°C) of the aliphatic epoxy compound (E) is 5 to 250,000 mPa·s.

6. The resin composition for phenol foam according to any one of claims 1 to 5, wherein the flame retardant contains a solid phosphorus-based flame retardant.

7. The resin composition for phenol foam according to claim 6, wherein the phosphorus-based flame retardant contains red phosphorus.

8. Furthermore, the resin composition for phenol foam according to any one of claims 1 to 7, further containing a plasticizer.

9. The resin composition for phenol foam according to claim 8, wherein the plasticizer comprises a polyester polyol.

10. The resin composition for phenol foam according to claim 8, wherein the plasticizer comprises an organic phosphate ester.

11. A foam obtained by foaming the resin composition for phenol foam according to any one of claims 1 to 10.

12. The foam according to claim 11, wherein the average percentage of closed cells in the surface layer and the center of the foam is 80% or more.

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