Foamed resin composition, furan resin foam with facing material, and method for producing the same

Abstract

To provide a foamable resin composition that can be used to mold high-quality furan resin foams. [Solution] A foaming resin composition comprising a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant, wherein the content of the furan ring-containing monomer is 25% by mass or less relative to the total mass of furan ring-containing compounds in the foaming resin composition.

Description

[Technical Field]

[0001] The present invention relates to a foamed resin composition, a furan resin foam with a facing material, and a method for producing the same. [Background technology]

[0002] Furan resin is a non-petroleum-based curing resin, and interest in furan resin is increasing due to growing concerns about resource and environmental issues. Patent documents 1 to 3 disclose a method for molding a furan resin foam by foaming and curing a foamable resin composition containing furan resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-open No. 1983-038362 [Patent Document 2] Japanese Patent Publication No. 2011-219621 [Patent Document 3] Japanese Patent Publication No. 2018-199752 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, conventional methods make it difficult to obtain high-quality furan resin foam. The present invention aims to provide a foamable resin composition capable of molding a high-quality furan resin foam, as well as a furan resin foam with a facing material having a high-quality furan resin foam, and a method for producing the same. [Means for solving the problem]

[0005] The inventors conducted thorough research and obtained the following findings. In Patent Document 1, the furfuryl alcohol (FFA) monomer content in the raw material furan resin is 50% or more. In Patent Document 2, the total content of FFA and furfural (FF) in the raw material furan resin (Hitafuran VF-302) is 28%. The high content of these monomers increases the heat generated during molding, making it difficult to control the molding process, and in some cases making molding impossible. Even if molding is possible, it results in a low-quality foam with issues such as bubble collapse during molding, coarse cells, and a large amount of residual monomer. Patent Document 3 describes the combined use of a furan resin prepolymer and a predetermined furan modifier having a predetermined structure with one or more furan rings. Since the furan modifier is insoluble in the furan resin prepolymer, it remains as an impurity in the foam, resulting in a low-quality foam. Conventionally, the foamed resin composition is filled into the mold during molding. In this case, the oxygen necessary for the curing of the furan resin is not supplied sufficiently, making curing difficult. The present invention is based on the above findings and has the following embodiments.

[0006] [1] A foaming resin composition containing a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant. A foaming resin composition in which the content of the furan ring-containing monomer (B) is 25% by mass or less relative to the total mass of the furan ring-containing compounds in the foaming resin composition. [2] A furan resin foam with a facing material, comprising a furan resin foam having a first surface and a second surface opposite to the first surface, and a facing material disposed on at least the first surface of the furan resin foam surface, The furan resin foam is obtained by foaming and curing the foaming resin composition described in [1], The air permeability of the aforementioned surface material is 0.1 [cm 3 / (cm 2 A furan resin foam with a facing material that is above (mmH2O·min) [3] A method for producing a furan resin foam with a facing material, which comprises foaming and curing a foaming resin composition containing a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant on at least one facing material. The content of the furan ring-containing monomer is 25% by mass or less based on the total mass of the furan ring-containing compounds in the foaming resin composition. The air permeability of the facing material is 0.1 [cm 3 / (cm 2 ·mmH2O·min)] or more. A method for producing a furan resin foam with a facing material, wherein at least one of the facing materials is in contact with an oxygen-containing atmosphere when the foaming resin composition is foamed and cured. [Advantages of the Invention]

[0007] According to the present invention, it is possible to provide a foaming resin composition capable of molding a high-quality furan resin foam, a furan resin foam with a facing material having a high-quality furan resin foam, and a method for producing the same. [Embodiments for Carrying Out the Invention]

[0008] The air permeability is a value measured by an air permeability measuring device (for example, manufactured by Tokiwa Seisakusho Co., Ltd.). The pH is a value at 25°C unless otherwise specified. The viscosity is a value measured by an E-type viscometer at 25°C. The weight average molecular weight of the furan resin prepolymer (hereinafter, also referred to as "Mw") is a polystyrene-equivalent value measured by gel permeation chromatography (hereinafter, also referred to as "GPC"). The water content is measured by the Karl Fischer method (for example, using "AQV-2200" manufactured by Hiranuma Co., Ltd. and the measuring reagent "Hydranal Composite 5" manufactured by Honeywell). The solid content is the non-volatile content (hereinafter, also referred to as "NV"). NV is the residue when the sample is heated at 135°C for 1 hour. The specific measurement method of NV is shown below. Weigh the mass C1 (g) of an aluminum foil dish (inner diameter 50 mm, height 15 mm), precisely weigh the sample so that it becomes 1.5 ± 0.1 g, and set the specific mass of the sample as the sample mass S (g) before drying. Place this aluminum foil dish in a thermostat preheated to 135 ± 1 °C, perform a drying treatment for 60 ± 2 minutes, then let it cool in a desiccator, and weigh its mass C2 (g). From the results, calculate the sample mass D (the mass of the sample remaining on the aluminum foil dish after the drying treatment) (g) by the following formula (1), and calculate the NV content (mass %) in the sample by the following formula (2). D = C2 - C1 ··· (1) NV content (mass %) = D / S × 100 ··· (2)

[0009] 〔Foamable resin composition〕 The foamable resin composition of the first embodiment contains a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant. The foamable resin composition may further contain a thermosetting compound that does not contain a furan ring. The foamable resin composition may further contain other components other than these.

[0010] <Furan resin prepolymer> The furan resin prepolymer can be obtained by polymerizing a monomer composition containing a furan ring-containing monomer. The monomer composition may further contain other monomers other than the furan ring-containing monomer. Examples of the polymerization method include, for example, a method of reacting a monomer composition in the presence of an acid catalyst. Thereby, the monomers are polymerized (condensed), and a reaction product containing a furan resin prepolymer (condensate) is obtained. After the reaction, an alkali may be used to neutralize the acid catalyst. The furan resin prepolymer may be, for example, a condensate of one furan ring-containing monomer, a co-condensate of two or more furan ring-containing monomers, a co-condensate of one or more furan ring-containing monomers and one or more other monomers, or a mixture of two or more of these. The reactant may contain unreacted monomers. If the reactant contains a furan ring-containing monomer, it can be used not only as a source of furan resin prepolymer but also as a source of furan ring-containing monomer in the preparation of a foamed resin composition. The furan ring-containing monomer may be added separately from the reactant.

[0011] The furan ring-containing monomer may be any monomer known as a monomer for furan resins, such as furfuryl alcohol, furfural, or hydroxymethylfurfural. The furan ring-containing monomer may be used alone or in combination of two or more.

[0012] Other monomers can be copolymerized (cocondensed) with furan ring-containing monomers, such as aldehydes, ketones, phenols, bisphenols, and urea. These other monomers may be used individually or in combination of two or more. Phenols are compounds having an aromatic ring and a hydroxyl group bonded to the aromatic ring. Phenols may be compounds known as monomers for phenolic resins, and examples include phenol, alkylphenols (o, m, p cresols, o, m, p ethylphenols, xylenol isomers, etc.), polyaromatic ring phenols (α, β naphthols, etc.), polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcinol, catechol, hydroquinone, etc.), and cardanol derived from cashew nuts. Phenols may be used individually or in combination of two or more. Aldehydes are at least one compound selected from the group consisting of compounds having a formyl group and their polymers, such as formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, and glyoxal. Aldehydes may be used individually or in combination of two or more.

[0013] The acid catalyst is not particularly limited as long as it facilitates the condensation reaction. Examples include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as oxalic acid, acetic acid, citric acid, tartaric acid, benzoic acid, and p-toluenesulfonic acid; and organic acid salts such as zinc acetate and zinc borate. The acid catalyst may be used alone or in combination of two or more types.

[0014] The alkali used for neutralization after reacting the monomer composition in the presence of an acid catalyst can be any alkali capable of neutralizing the acid catalyst, and various alkaline substances can be used. Specific examples include inorganic alkaline substances such as alkali metal hydroxides (sodium hydroxide, potassium hydroxide, etc.), alkaline earth metal hydroxides (calcium hydroxide, magnesium hydroxide, barium hydroxide, etc.), sodium carbonate, and ammonia; organic alkaline substances such as tertiary amines (triethylamine, trimethylamine, triethanolamine, etc.) and cyclic amines (1,8-diazabicyclo[5.4.0]undeca-7-ene (DBU), 1,5-diazabicyclo[4.3.0]nona-5-ene (DBN)); and others. These alkaline substances may be used individually or in combination of two or more.

[0015] The weight-average molecular weight (Mw) of the furan resin prepolymer is preferably 200 to 20,000, and more preferably 500 to 10,000. The viscosity of the reactant is preferably 300 to 400,000 mPa·s, and more preferably 500 to 400,000 mPa·s. The higher the viscosity of the reactants, the greater the Mw of the furan resin prepolymer tends to be, or the lower the amount of residual monomer. A higher Mw of the furan resin prepolymer results in a higher yield during synthesis, less heat generation during curing, and easier control of molding. On the other hand, if the viscosity is below the above upper limit, the viscosity of the foaming resin composition becomes low, and it expands easily with the foaming agent.

[0016] The solid content of the reactant is preferably 30 to 100% by mass, more preferably 40 to 95% by mass, and even more preferably 50 to 90% by mass, relative to the total mass of the reactant. When the solid content is within the above range, it is easier to keep the viscosity of the reactant within the preferred range described above.

[0017] <Furan ring-containing monomers> Examples of furan ring-containing monomers include compounds in which a methylol group and / or a formyl group is bonded to a furan ring (hereinafter also referred to as "compound B1"), derivatives of compound B1, and compounds containing one or more furan rings and hydroxyl groups bonded to the furan rings via two or more carbon atoms (excluding compound B1 and its derivatives) (hereinafter also referred to as "compound B2"). In compound B1, other substituents besides the methylol group and the formyl group may be bonded to the furan ring. Examples of other substituents include alkyl groups such as methyl groups. In compound B1, the furan ring may form a fused ring with another ring. An example of such another ring is a benzene ring. Examples of compound B1 include furfuryl alcohol (FFA), furfural (FF), hydroxymethylfurfural (HMF), 5-methyl-2-furfural, and benzofuran-2-carbaldehyde. Examples of derivatives of compound B1 include Freun. Examples of compound B2 include the compounds described in Japanese Patent Publication No. 2018-199752, and specific examples include 2-(furan-2-yl)ethanol, 3-(furan-2-yl)propan-1ol, 4-(furan-2-yl)butan-1ol, 1-(furan-2-yl)propan-2ol, and 1,5-bis(furan-2-yl)pentan-3ol. As the furan ring-containing monomer, compound B1 is preferred, and furfuryl alcohol, furfural, and hydroxymethylfurfural are more preferred. The furan ring-containing monomer may be used alone or in combination of two or more types.

[0018] <Thermosetting compounds that do not contain a furan ring> Examples of thermosetting compounds that do not contain a furan ring include phenolic resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, alkyd resins, and thermosetting polyimide resins. Phenolic resins are preferred from the viewpoint of heat resistance. As for the phenolic resin, resol-type phenolic resins are preferred because, like franc prepolymers, they harden when exposed to acid.

[0019] Resol-type phenolic resins, also known as alkaline phenolic resins, typically contain addition condensates of phenols with aldehydes (phenolic condensates), an alkaline substance, and water. At least a portion of the alkaline substance is usually an alkaline catalyst used in the production of the resol-type phenolic resin. The alkaline catalyst may be neutralized.

[0020] The pH of the resol-type phenolic resin is preferably 5 to 12, more preferably 5.5 to 10, and even more preferably 6.0 to 8.0. When the pH is above the lower limit, the phenolic-type resolic resin exhibits excellent long-term stability. When the pH is below the upper limit, less acid catalyst needs to be added during foam molding.

[0021] The weight-average molecular weight (Mw) of the resol-type phenolic resin is preferably 300 to 20,000, more preferably 500 to 15,000, even more preferably 800 to 10,000, particularly preferably 900 to 8,000, and most preferably 1,000 to 6,000. If the weight-average molecular weight of the resol-type phenolic resin is above the lower limit, there tends to be less unreacted monomer components in the resol-type phenolic resin, resulting in less odor when the resin is used. If it is below the upper limit, the viscosity tends to be low, and it tends to mix easily with other raw materials.

[0022] The viscosity of the resol-type phenolic resin is preferably 10 to 200,000 mPa·s, more preferably 30 to 150,000 mPa·s, even more preferably 50 to 100,000 mPa·s, particularly preferably 100 to 90,000 mPa·s, and most preferably 200 to 80,000 mPa·s. If the viscosity of the resol-type phenolic resin is above the lower limit, it is easy to emulsify during foam molding, and if it is below the upper limit, it is easy to mix with other raw materials.

[0023] The solid content of the resol-type phenolic resin is preferably 30 to 100% by mass, more preferably 35 to 95% by mass, and even more preferably 40 to 90% by mass, relative to the total mass of the resol-type phenolic resin. When the solid content is within the above range, it is easier to maintain the viscosity of the resol-type phenolic resin within the aforementioned preferred range.

[0024] Examples of phenols and aldehydes include those listed in the description of furan resin prepolymers. Regarding phenols, those other than resorcinol are preferred in terms of storage stability of resol-type phenolic resins. Practical phenols other than resorcinol include phenol, the O, M, and P cresols, the various isomers of xylenol, and cardanol. The practical aldehydes are formaldehyde and paraformaldehyde.

[0025] There are no particular restrictions on the alkaline catalyst as long as it can facilitate the addition-condensation reaction, and various alkaline substances can be used. Specific examples include inorganic alkaline substances such as hydroxides of alkali metals like sodium and potassium (sodium hydroxide, potassium hydroxide, etc.), oxides and hydroxides of alkaline earth metals like calcium, magnesium, and barium, sodium carbonate, and ammonia; organic alkaline substances such as tertiary amines like triethylamine and trimethylamine, and cyclic amines like DBU (1,8-diazabicyclo[5.4.0]undeca-7-ene) and DBN (1,5-diazabicyclo[4.3.0]nona-5-ene); and so on. The alkaline catalyst may be used alone or in combination of two or more types.

[0026] Resol-type phenolic resins can be obtained, for example, by reacting phenols and aldehydes only in the presence of an alkaline catalyst. The phenols, aldehydes, and alkaline catalyst are the same as those described above. The production of this reaction product can be carried out by known methods.

[0027] The preferred amount of alkaline catalyst to be used when reacting phenols and aldehydes in the presence of an alkaline catalyst is determined by the molar ratio of the alkaline catalyst to the phenol (hereinafter also referred to as the "alkali / P molar ratio"). The alkali / P molar ratio is preferably 0.001 to 1.0, more preferably 0.005 to 0.9, and even more preferably 0.01 to 0.8. If the alkali / P molar ratio is above the lower limit, a resol-type phenolic resin can be obtained quickly, and if it is below the upper limit, the resol reaction is easier to control.

[0028] The molar ratio of aldehydes to phenols (hereinafter also referred to as the "F / P molar ratio") is preferably 1.0 to 3.5, more preferably 1.1 to 3.0, and even more preferably 1.2 to 2.5. When the F / P molar ratio is above the lower limit, a sufficient amount of methylol groups is present in the resol-type phenolic resin, allowing for sufficient crosslinking reaction during curing and the production of a high-strength foam. When the F / P molar ratio is below the upper limit, the amount of free aldehydes volatilized during foam production and the amount of formaldehyde emitted from the foam are reduced.

[0029] <Curing catalyst> Depending on the type of curable compound (furan resin prepolymer, furan ring-containing monomer, etc.) contained in the foamed resin composition, a known curing catalyst can be used.

[0030] Acid catalysts are typically used as curing catalysts for furan resin prepolymers and furan ring-containing monomers. Examples of acid catalysts include inorganic acids such as sulfuric acid, phosphoric acid, and hydrochloric acid; and organic acids such as organic sulfonic acids and carboxylic acids. Organic sulfonic acids are organic compounds in which a sulfo group is substituted on a carbon skeleton. Examples of organic sulfonic acids include xylene sulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, and phenolsulfonic acid. These sulfonic acids may be used individually or in combination of two or more. Examples of carboxylic acids include formic acid, acetic acid, oxalic acid, lactic acid, maleic acid, malic acid, citric acid, tartaric acid, malonic acid, succinic acid, and benzoic acid. These acids containing carboxylic acids may be used individually or in combination of two or more.

[0031] As an acid catalyst, sulfonic acid compounds are preferred in terms of their higher strength and heat resistance, and among them, xylene sulfonic acid, p-toluenesulfonic acid, and phenolsulfonic acid are particularly preferred in terms of their excellent performance as a curing catalyst. As an acid catalyst, it is preferable to use at least an organic acid, from the viewpoint of having a longer pot life and improved strength. Inorganic acids and organic acids may be used in combination as acid catalysts. When using inorganic and organic acids in combination, it is preferable to use a larger proportion of organic acids than inorganic acids. If the foamed resin composition contains a resol-type phenolic resin, an acid catalyst and an organic acid ester may be used in combination.

[0032] <Foaming agent> Known blowing agents can be used, such as water, liquefied carbon dioxide, hydrogen atom-containing carbon halides, and low-boiling point hydrocarbons. Examples of hydrogen atom-containing halogenated hydrocarbons include hydrochlorofluorocarbons (HCFCs) such as HFC-245fa and HFC-365mfc; and hydrofluoroolefins (HFOs) such as HFO-1336mzz(Z) and HFO-1233zd. Examples of low-boiling-point hydrocarbons include hydrocarbons with a boiling point of -5 to 70°C, specifically butane, pentane, isopentane, and cyclopentane. As a foaming agent, isopentane is preferred from the viewpoint of compatibility with furan resin prepolymers. The foaming agent may be used alone or in combination of two or more types.

[0033] <Surfactants> Surfactants are added to the foaming resin composition for the purpose of emulsifying it and forming cells during molding. As the surfactant, known surfactants can be used, such as cationic surfactants, anionic surfactants, and nonionic surfactants. As a surfactant, a nonionic surfactant is preferred from the viewpoint of its ease of emulsifying the foaming resin composition. Surfactants may be used individually or in combination of two or more types.

[0034] <Other ingredients> Other components include, for example, flame retardants, colorants (dyes, pigments, etc.), plasticizers (tris(β-chloropropyl) phosphate, phthalates, adipicates, etc.), oxygen generators (hydrogen peroxide, sodium percarbonate, etc.), organic fillers (synthetic short fibers, hollow microspheres made of thermoplastic or thermosetting resins, etc.), antioxidants (hindered phenols, hindered amines, etc.), anti-aging agents (triazoles, benzophenones, etc.), and mold release agents (waxes, metal soaps, or mixtures thereof). Other components may be used individually or in combination of two or more.

[0035] <Content of each ingredient> The content of furan ring-containing monomers is 25% by mass or less, preferably 20% by mass or less, preferably 0.1% by mass or more, and more preferably 0.2% by mass or more, relative to the total mass of furan ring-containing compounds in the foamed resin composition. When the content of furan ring-containing monomers is below the above upper limit, the heat generated during curing is small, molding is easy to control, and a high-quality furan resin foam can be obtained. When the content of furan ring-containing monomers is above the above lower limit, the viscosity of the foam composition decreases and the compatibility is further improved. The total mass of furan ring-containing compounds in a foamed resin composition is typically the total mass of the furan resin prepolymer and the furan ring-containing monomer.

[0036] The content of furan ring-containing monomers is preferably less than 25% by mass, more preferably less than 20% by mass, and preferably 0.1% by mass or more, and more preferably 0.2% by mass or more, based on the total mass of the foamed resin composition.

[0037] The content of furan ring-containing monomers other than compound B1 is preferably less than 25% by mass, more preferably less than 10% by mass, and may be 0% by mass, based on the total mass of furan ring-containing compounds in the foamed resin composition.

[0038] The content of furan ring-containing monomers other than furfuryl alcohol, furfural, and hydroxymethylfurfural is preferably less than 25% by mass, more preferably less than 10% by mass, and may be 0% by mass, based on the total mass of furan ring-containing compounds in the foamed resin composition.

[0039] The content of thermosetting compounds that do not contain furan rings is preferably 95% by mass or less, more preferably 90% by mass or less, and may be 0% by mass, based on the total mass of thermosetting compounds that do not contain furan rings. When the content of thermosetting compounds that do not contain furan rings is below the above upper limit, the biomass raw material usage ratio of the molded product increases.

[0040] The content of the curing catalyst is preferably 0.01 to 20% by mass, and more preferably 0.1 to 10% by mass, relative to the total mass of the furan ring-containing compound and the thermosetting compound that does not contain a furan ring. If the content of the curing catalyst is above the lower limit, the curing reaction proceeds more easily, resulting in better strength of the molded product. If it is below the upper limit, the heat generated during curing is easier to control, resulting in better moldability.

[0041] The content of the blowing agent is preferably 0.1 to 50% by mass, and more preferably 1 to 40% by mass, relative to the total mass of the furan ring-containing compound and the thermosetting compound that does not contain a furan ring. If the content of the blowing agent is above the lower limit, the viscosity of the foam composition will be lower and the miscibility will be better, and if it is below the upper limit, the decrease in foam strength due to excessive expansion can be suppressed.

[0042] The surfactant content is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass, relative to the total mass of the furan ring-containing compound and the thermosetting compound that does not contain a furan ring. If the surfactant content is above the lower limit, the foam composition is easier to emulsify and has better moldability. If it is below the upper limit, the composition of furan ring-containing compounds and thermosetting compounds that do not contain a furan ring increases, resulting in better foam strength.

[0043] The natural origin percentage of the foamed resin composition is preferably 5% by mass or more, and more preferably 10% by mass or more. A higher natural origin percentage is preferable, and there is no particular upper limit, but for example, it is 99% by mass or less. A natural origin percentage of or above the lower limit is preferable in terms of carbon neutrality. A natural origin percentage of or below the upper limit is preferable because there are fewer impurities in the composition, making it easier to manufacture the foam. The natural origin percentage is the mass ratio of naturally derived raw materials to the total mass of the resin composition.

[0044] The viscosity of the foamed resin composition is preferably 100 to 200,000 mPa·s, and more preferably 200 to 100,000 mPa·s. If the viscosity of the foamed resin composition is above the lower limit, seepage onto the surface material can be suppressed, and emulsification of the foaming agent is easy. If it is below the upper limit, it is prone to swelling by the foaming agent.

[0045] The foamed resin composition can be manufactured by mixing a furan resin prepolymer, a furan ring-containing monomer, a curing catalyst, a foaming agent, a surfactant, and other components as needed. Since foaming and curing occur when the furan resin prepolymer comes into contact with the curing catalyst, it is preferable to prepare a premixture containing components other than the curing catalyst in advance, and then mix the premixture with the curing catalyst immediately before molding the furan resin foam.

[0046] [Furan resin foam with facing material] The furan resin foam with a facing material of the second embodiment comprises a furan resin foam having a first surface and a second surface opposite to the first surface, and a facing material disposed on at least the first surface of the furan resin foam.

[0047] <Furan resin foam> The furan resin foam is obtained by foaming and curing the foamable resin composition of the first embodiment described above.

[0048] The density of furan resin foam is 1 to 80 kg / m³. 3 Preferably, 5-70 kg / m 3is more preferable, and 10 to 60 kg / m 3 is even more preferable. The density is measured by the method described in the examples below.

[0049] The compression strength of the furan resin foam is 0.1 N / cm 2 or more is preferable, 0.3 N / cm 2 or more is more preferable, 0.5 N / cm 2 or more is even more preferable. The compression strength is measured by the method described in the examples below.

[0050] The thermal conductivity of the furan resin foam is preferably 0.060 W / m·K or less, more preferably 0.050 W / m·K or less, and even more preferably 0.040 W / m·K or less. The thermal conductivity is measured by the method described in the examples below.

[0051] The shape of the furan resin foam may be any as long as it has a first surface and a second surface opposite to the first surface. Typically, it has a first surface, a second surface, and one or more surfaces (hereinafter also referred to as "side surfaces") connecting the outer edges thereof. For example, a polyhedron such as a rectangular parallelepiped, a cylindrical shape, etc. can be mentioned. The distance between the first surface and the second surface is, for example, 0.01 to 2 m.

[0052] <Face material> The face material has an air permeability of 0.1 [cm 3 / (cm 2 ·mmH2O·min)] or more, and 0.3 [cm 3 / (cm 2 ·mmH2O·min)] or more is preferable. When the air permeability is at least the above lower limit value, when molding the furan resin foam with a face material, the foaming resin composition can be sufficiently cured in a short time at a low temperature, and the molding of the furan resin foam becomes easy. The air permeability of the face material is preferably 3000 [cm 3 / (cm 2 ·mmH2O·min)] or less in terms of the difficulty of the foaming resin composition infiltrating into the face material during foam molding, and 2000 [cm 3 / (cm2 The following is more preferable: (mmH2O·min)

[0053] The facing material can be any material that satisfies the aforementioned requirements for breathability, and is not particularly limited, but examples include nonwoven fabrics, woven fabrics, knitted fabrics and other fibrous materials, and paper. Examples of materials used to make up textile fabrics include polyethylene (PE), polypropylene (PP), and nylon. The weight of the facing material is 10-500 g / m². 2 Preferably, 20-400 g / m² 2 This is preferable.

[0054] <Method for manufacturing furan resin foam with facing material> The furan resin foam with a facing material of this embodiment can be manufactured, for example, by foaming and curing the foamable resin composition of the first embodiment described above on at least one facing material.

[0055] When foaming and curing a foamable resin composition, it is preferable that at least one facing material is in contact with an oxygen-containing atmosphere. This ensures that sufficient oxygen is supplied for the curing of the furan resin prepolymer, allowing curing to proceed in a short time and at low temperatures, and enabling easy molding of the furan resin foam. The surface area of ​​the material in contact with the oxygen-containing atmosphere is preferably 1 to 100%, more preferably 3 to 90%, and even more preferably 5 to 80% of the surface area of ​​the foam. The oxygen-containing atmosphere may be, for example, air. Methods for foaming and curing a foamable resin composition while at least one surface material is in contact with an oxygen-containing atmosphere include, for example, forming a container with a shape corresponding to the furan resin foam to be molded using the surface material, placing the foamable resin composition in this container, and foaming and curing it in an oxygen-containing atmosphere; and foaming and curing the foamable resin composition on a surface material placed on a mesh in an oxygen-containing atmosphere.

[0056] To foam and cure a foaming resin composition, for example, the foaming resin composition can be held at a predetermined temperature for a predetermined time. The temperature required for foaming and curing (curing temperature) varies depending on the type of foaming agent, but is typically between 40 and 120°C. The time required to maintain the curing temperature (curing time) also varies depending on the curing temperature, but is typically between 1 and 60 minutes.

[0057] After foaming and curing, a portion of the surface material may be peeled off from the furan resin foam. Curing may be performed after foaming and hardening. The curing temperature is, for example, 40 to 200°C. The curing time is, for example, 0.5 to 100 hours. At least one surface of the obtained furan resin foam is in contact with the facing material. Any one of the surfaces in contact with the facing material is designated as the first surface. The surface opposite to the first surface may be left as the second surface, or the surface opposite to the first surface may be cut and the cut surface may be designated as the second surface. [Examples]

[0058] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "mass%". "Parts" means "parts by mass".

[0059] <Synthesis of furan resin prepolymer> [Synthesis Example 1] 3500 parts of furfuryl alcohol (FFA) and 1.26 parts of 50% p-toluenesulfonic acid were charged into a reactor equipped with a condenser, thermometer, and stirrer. After reacting at 80°C for 1 hour, the mixture was cooled to below 40°C, and 1.33 parts of 48% sodium hydroxide aqueous solution were added. Subsequently, the mixture was heated to 200°C under a vacuum of 680 mmHg to remove water and FFA monomers, yielding reaction product A containing a furan resin prepolymer.

[0060] [Synthesis Examples 2-4] Reactants B, C, and D containing furan resin prepolymer were obtained in the same manner as in Synthesis Example 1, except for a change in reaction time. Note that longer reaction times tend to result in higher Mw, higher viscosity, and lower levels of free FFA.

[0061] Table 1 shows the weight-average molecular weight (Mw) of the furan resin prepolymer contained in each reactant, the viscosity of each reactant, the FFA monomer content, and the water content.

[0062] [Table 1]

[0063] Mw, free FFA, viscosity, and moisture content were measured using the following methods. [Mw, free FFA] GPC measurements were performed under the following conditions, and the weight-average molecular weight in polystyrene terms was determined from the results. Columns: TSKgel G3000HXL 7.8×300mm × 1 (manufactured by Tosoh Corporation), TSKgel G2000HXL 7.8×300mm × 2 (manufactured by Tosoh Corporation). Column temperature: 40°C. Detector: RI (Differential Refractive Index Detector). Solvent: THF (tetrahydrofuran). Flow rate: 0.8mL / min. During the above measurement, a calibration curve was created using FFA monomer, and the amount of FFA monomer was determined from the area ratio of the corresponding peaks on the GPC chart.

[0064] [viscosity] Viscosity was measured using an E-type viscometer at 25°C. [moisture] The moisture content was measured using HIRANUMA AQUACOUNTER AQV-2200 (Karl Fischer solution: Honeywell HYDRANAL Composite 5).

[0065] <Test Example 1> A rectangular container with an open top (internal dimensions: length x width x height = 700mm x 700mm x 500mm) was created by folding the facing material. The facing material is polypropylene (PP) nonwoven fabric (basis weight 70g / m²). 2 , breathability 240 [cm 3 / (cm 2 (mmH2O·min) was used. According to the formulation shown in Table 2, the raw materials other than the curing catalyst were mixed, the curing catalyst was added to the resulting mixture, and the mixture was stirred with a hand mixer for 10 seconds. The resulting foamed resin composition was quickly poured into the above container. This container was placed in a 60°C dryer and heated for 10 minutes. After that, it was cured at 80°C for 5 hours to obtain a furan resin foam with a facing material. In Table 2, the following raw materials other than the reactants were used. Surfactant: Sorbitan fatty acid ester, Daiichi Kogyo Seiyaku Co., Ltd. "TW-80" Foaming agent: Isopentane Plasticizer: Tris(β-chloropropyl) phosphate Furan derivatives: Freun FFA: Furfuryl alcohol Furfural HMF: Hydroxymethylfurfural Curing catalyst: 65% phenol sulfonic acid aqueous solution

[0066] The facing material was removed from the obtained furan resin foam, and the density, compressive strength, and thermal conductivity of the furan resin foam were measured. The results are shown in Table 2. Density, compressive strength, and thermal conductivity were measured using the following methods. [density] A 50mm x 50mm x 50mm sample was cut from furan resin foam, and the density was calculated by dividing the sample's mass by its volume. [Compressive strength] In accordance with JIS K 7220, a 50mm x 50mm x 25mm sample was cut from furan resin foam, and the sample was compressed by 10% relative to its thickness. The compressive stress was measured, and the value obtained by dividing the compressive stress by the cross-sectional area was defined as the compressive strength. [Thermal conductivity] Measurements were taken using a Hot Disk TPS-1500.

[0067] [Table 2]

[0068] By setting the content of furan ring-containing monomers to 25% by mass or less relative to the total mass of furan ring-containing compounds in the foaming resin composition, a high-quality foam could be molded.

[0069] <Test Example 2> A furan resin foam with a facing material was prepared in the same manner as in Example 2, except that the facing material was the one shown in Table 3. In Table 3, "PE" indicates polyethylene. The curability and voids were evaluated using the following procedure. The results are shown in Table 3.

[0070] [Curability] The facing material was peeled off the furan resin foam with the facing material attached before curing, and the stickiness of the furan resin foam surface was checked by touch and evaluated according to the following criteria. ○: Hardening is progressing, and there is no stickiness on the surface. ×: Insufficient curing; the surface is sticky and soft.

[0071] [Void] After curing, a 10mm section from the bottom of the furan resin foam with facing material was cut horizontally, and the cross-section was visually inspected and evaluated according to the following criteria. ○: The cells are formed to be of uniform size. ×: The cells are not uniform in size, and some large bubbles with a diameter of 10 mm or more are visible.

[0072] [Table 3]

[0073] Air permeability is 0.1 [cm] 3 / (cm 2 By using a surface material with a density of (mmH2O) or higher, we were able to mold a high-quality foam.

[0074] <Test Example 3> A furan resin foam with a facing material was prepared in the same manner as in Example 20, except that a portion of the reactants was replaced with phenolic resin according to the formulation shown in Table 4. XPL-6871B (resol-type phenolic resin) manufactured by Gun-ei Chemical Industry Co., Ltd. was used as the phenolic resin. The facing materials were removed from the furan resin foams with facing materials in Examples 20-23, and the density, compressive strength, and thermal conductivity of the furan resin foams were measured in the same manner as in Test Example 1. The results are shown in Table 4.

[0075] [Table 4]

[0076] Even when using phenolic resin in combination, we were able to mold high-quality foam.

[0077] <Comparative Example 4> A common foam material, urethane resin foam (urethane foam), was manufactured using the following procedure. 50 parts of polypropylene glycol (Mw400), 10 parts of tris(β-chloropropyl) phosphate, 11.1 parts of water, 3.6 parts of surfactant (Dow-Toray: SH-193), and catalyst (Kao Corporation: Kaorizer No. 120) were mixed together, then polymeric MDI (Tosoh Corporation: MR-200) was added, and the mixture was stirred with a hand mixer for 10 seconds. The resulting foamed resin composition was poured into a 300 mL poly cup and molded at room temperature. After that, it was cured at 80°C for 5 hours to obtain a urethane resin foam.

[0078] The density, compressive strength, and thermal conductivity of the obtained urethane resin foam were measured in the same manner as in Test Example 1. The results are shown in Table 5. Table 5 also shows the results for Example 1, along with the percentage of naturally derived materials in the raw materials for Example 1 and Comparative Example 4.

[0079] [Table 5]

[0080] According to the present invention, foams using naturally derived raw materials can be manufactured with the same properties as conventional methods.

Claims

1. This foaming resin composition contains a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant. A foaming resin composition in which the content of the furan ring-containing monomer is 25% by mass or less relative to the total mass of the furan ring-containing compounds in the foaming resin composition.

2. A furan resin foam with a facing material, comprising a furan resin foam having a first surface and a second surface opposite to the first surface, and a facing material disposed on at least the first surface of the furan resin foam's surface, The furan resin foam is obtained by foaming and curing the foamed resin composition described in claim 1. The air permeability of the aforementioned surface material is 0.1 [cm] ３ / (cm ２ mmH ２ A furan resin foam with a facing material that is 0 min or larger.

3. A method for producing a furan resin foam with a surface material, comprising foaming and curing a foamable resin composition containing a furan resin prepolymer (excluding monomers), a furan ring-containing monomer, a curing catalyst, a foaming agent, and a surfactant on at least one surface material. The content of the furan ring-containing monomer is 25% by mass or less relative to the total mass of the furan ring-containing compounds in the foamed resin composition. The air permeability of the aforementioned surface material is 0.1 [cm] ３ / (cm ２ mmH ２ (O min) is greater than or equal to, A method for producing a furan resin foam with a facing material, wherein at least one of the facing materials comes into contact with an oxygen-containing atmosphere when the foaming resin composition is foamed and cured.

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