Phenol resin foam and its laminate

Abstract

A foamed phenolic-resin object containing a hydrofluoroether represented by (formula 1) in an amount of 0.03-4.3 mass%. (Formula 1): CaHbFc-O-CxHyFz (where a, b, c, x, y, and z are integers, and 2≤a≤7, 0≤b≤3, c=2a+1-b, b≤2a+1, 1≤x≤3, 2≤y≤7, z=2×x+1-y, and y≤2x+1)

Description

Cross-reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2022-071172, filed in Japan on April 22, 2022, and incorporates the entire disclosure of the prior application herein by reference.

Technical Field

[0002] The present invention relates to a phenolic resin foam and a laminated board thereof.

Background Art

[0003] Foamed plastic-based heat insulating materials, unlike fibrous glass wool and rock wool, contain a gas with a low thermal conductivity in the bubbles, showing even higher heat insulating performance. Therefore, in addition to exterior wall materials such as metal siding and wall materials without partition panels, they are widely used in building materials such as ceiling materials, fire doors, and shutters.

[0004] In recent years, due to concerns about global warming, the reduction of greenhouse gas emissions has become an urgent task. Among them, high heat insulation of buildings has attracted attention as one of the means to reduce greenhouse gas emissions through energy conservation. Since the higher the heat insulation performance, the greater the energy conservation effect, further improvement of heat insulation performance has been demanded.

[0005]

[0006] Patent Document 1 discloses that a phenolic resin foam with high heat insulation performance can be obtained by adding a fluoroether having an effect of reducing the cell diameter and reducing the cell diameter of the phenolic resin foam. Patent Document 2 also discloses that by adding a powdery phenolic resin solidified product, the cell diameter of the phenolic resin foam can be reduced and high heat insulation can be achieved.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-140217 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-210618 [Summary of the Invention] [Problems to be Solved by the Invention]

[0008] However, the Galden listed in the examples of fluoroethers in Patent Document 1 is expensive, and its global warming potential (GWP) is high, making it difficult to use actively due to its relatively large environmental impact. In addition, the effect of reducing the bubble diameter is limited to the use of hydrocarbons as the blowing agent, and no adaptation has been made for the case of using hydrofluoroolefins with low thermal conductivity as the blowing agent.

[0009] On the other hand, although Patent Document 2 is a technique for reducing the bubble diameter even when hydrofluoroolefins are used as the blowing agent, adding a powdered phenolic resin solidified product increases the heat conduction of the solid, so it is hard to say that it is preferable as a method for reducing the thermal conductivity. In addition, when the amount of the powdered phenolic resin solidified product added is large, it is likely to stay in the piping, block the piping, and reduce productivity. Furthermore, the powdered phenolic resin solidified product requires not only equipment for producing the powder but also equipment for kneading the powder into the resin, resulting in a high equipment investment.

[0010] Therefore, the inventors of the present invention believe that there are three main perspectives as the main methods for improving the heat insulation performance of resin foams, that is, reducing the thermal conductivity. The first is to "use a gas with low thermal conductivity", the second is to "refine the bubble diameter of the foam", and the third is to "reduce the density of the foam". Regarding the third "density reduction", it is not a practical solution because it causes problems such as the inability to maintain the closed-cell ratio of the resin foam due to density reduction and a decrease in mechanical properties. Also, generally, the first consideration is actively carried out because of the large contribution effect on the thermal conductivity.

[0011] Based on the first perspective, CFCs and HFCs, which have low thermal conductivity, were widely used in the past. However, because both have high ozone depletion potentials (ODPs), their use has been restricted, and currently, hydrofluoroolefins, which have comparable thermal conductivity, an ODP of 0, and low GWPs, are the mainstream alternatives. However, addressing only the first perspective has limitations in improving thermal conductivity, and further improvements in thermal conductivity require mastering the second perspective, "reducing the size of bubbles in the foam."

[0012] This second perspective is based on the following specific ideas: Firstly, it is important to create as many bubble nuclei as possible in the resin composition. Secondly, it is important to allow the generated bubbles to grow stably without bursting, and achieving both of these conditions makes it possible to miniaturize bubbles. Since miniaturizing the bubble diameter suppresses radiant heat conduction of the foam, it can be said that miniaturizing the bubble diameter is the second most significant factor contributing to thermal conductivity after "using a gas with low thermal conductivity."

[0013] Therefore, in order to reduce the thermal conductivity of phenolic resin foam, a technology was needed to refine the bubble size when using various blowing agents. [Means for solving the problem]

[0014] [1] The hydrofluoroether represented by the following formula (Formula 1) is contained in an amount of 0.03 to 4.3% by mass relative to the phenolic resin foam. The foaming agent contains hydrofluoroolefin, The closed-cell ratio is 80% or more. the law of nature, The average bubble diameter is between 70 μm and 180 μm. A phenolic resin foam. Formula 1:C a H b F c -OC x H y F z (However, a, b, c, x, and y are integers, where 2 ≤ a ≤ 7, 0 ≤ b ≤ 3, c = 2a + 1 - b, b ≤ 2a + 1, 1 ≤ x ≤ 3, 2 ≤ y ≤ 7, and z = 2x + 1 - y, with y ≤ 2x + 1) [2] The phenolic resin foam according to [1], wherein the hydrofluoroether represented by (Formula 1) is any one of methyl perfluoropropyl ether, methyl nonafluorobutyl ether, methyl nonafluoroisobutyl ether, ethyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, 1,1,1,2,2,3,4,5,5,5 - decafluoro - 3 - methoxy - 4 - (trifluoromethyl) - pentane, and 1,1,2,2 - tetrafluoroethyl - 2,2,2 - trifluoroethyl ether 。 [3 The phenolic resin foam according to [1], wherein the foaming agent contains hydrocarbons or [2] 4 The phenolic resin foam according to any one of [1] to 3 having a density of 10 kg / m 3 or more and 70 kg / m 3 or less 5 A laminate of the phenolic resin foam according to any one of [1] to 4 having a surface material provided on at least one of one surface and the back surface of the phenolic resin foam

[0015] [1] A phenolic resin foam containing the hydrofluoroether represented by the following (Formula 1) in an amount of 0.03 to 4.3% by mass based on the phenolic resin foam Formula 1: C a H b F c -O-C x H y F z ​​​​​​(However, a, b, c, x, y, z are integers, and 2 ≤ a ≤ 7, 0 ≤ b ≤ 3, c = 2a + 1 - b, b ≤ 2a + 1, 1 ≤ x ≤ 3, 2 ≤ y ≤ 7, z = 2 × x + 1 - y, y ≤ 2x + 1) [2] The phenol resin foam according to [1], wherein the hydrofluoroether represented by (Formula 1) is any of methyl perfluoropropyl ether, methyl nonafluorobutyl ether, methyl nonafluoroisobutyl ether, ethyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether. [3] A phenolic resin foam according to [1] or [2], wherein the average bubble diameter is 70 μm or more and 180 μm or less. [4] A phenolic resin foam according to any one of [1] to [3], wherein the foaming agent contains a hydrofluoroolefin. [5] A phenolic resin foam according to [4], wherein the foaming agent contains a hydrocarbon. [6] Density is 10 kg / m³ 3 More than 70kg / m 3 A phenolic resin foam as described in any of the following [1] to [5]. [7] A phenolic resin foam according to any of [1] to [6], wherein the closed-cell ratio is 80% or more. [8] A laminate of phenolic resin foam according to any one of [1] to [7], comprising a surface material on at least one of one side of the phenolic resin foam and the back surface of said side. [Effects of the Invention]

[0016] The phenolic resin foam and its laminate according to the present invention can reduce the size of the bubbles in the phenolic resin foam. Since the bubble size contributes to a reduction in thermal conductivity, the thermal conductivity can be reduced when using each blowing agent. Furthermore, these issues are particularly improved when there are appearance defects such as voids or uneven coloring of the foam, or when the compressive strength is low, when hydrofluoroether is not added. Moreover, because the GWP of the raw materials is low, it is possible to provide an environmentally friendly foam with a low environmental impact. [Modes for carrying out the invention]

[0017] The embodiments for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail below. It should be noted that the present invention is not limited to the following embodiments and can be implemented with various modifications within the scope of its gist. Furthermore, in this specification, a "phenol resin composition" is used to describe a "phenol resin composition" to which a surfactant has been added, and a "foaming phenol resin composition" is used to describe a "phenol resin composition" to which a hydrofluoroether, foaming agent, foaming nucleating agent, and acid curing agent have been added to impart foaming properties or both foaming and curing properties. The resulting foam is referred to as "phenol resin foam."

[0018] <Phenolic resin foam> The phenolic resin foam of this embodiment is produced from a phenolic resin composition containing a hydrofluoroether, a foaming agent, and an acidic curing agent.

[0019] The hydrofluoroether contained in the phenolic resin foam of this embodiment is represented by (Formula 2). Formula 2:C a H b F c -OC x H y F z (However, a, b, c, x, y, z are integers, and 2 ≤ a ≤ 7, 0 ≤ b ≤ 3, c = 2a + 1 - b, b ≤ 2a + 1, 1 ≤ x ≤ 3, 2 ≤ y ≤ 7, z = 2 × x + 1 - y, y ≤ 2x + 1)

[0020] Adding this hydrofluoroether to a phenolic resin or phenolic resin composition reduces the size of the bubbles in the phenolic resin foam. Generally, the hydrofluoroether content is 0.03% to 4.3% by mass relative to the phenolic resin foam, preferably 0.1% to 3.8% by mass, more preferably 0.3% to 3.3% by mass, and most preferably 0.5% to 3.3% by mass. This hydrofluoroether may be a combination of two or more molecules corresponding to formula 2. If the hydrofluoroether content is 0.03% by mass or more, the thermal conductivity tends to be low. Furthermore, if the hydrofluoroether content is 4.3% by mass or less, even when using a hydrofluoroether with a high boiling point, there is little concern that the thermal conductivity will increase or the rigidity of the phenolic resin will decrease due to an increase in the amount of hydrofluoroether liquefied in the foam. In this embodiment, in order to set the hydrofluoroether content in the phenolic resin foam within the above range (0.03% by mass to 4.3% by mass), the amount of hydrofluoroether added per 100 parts by mass of the phenolic resin composition is preferably 0.1 parts by mass to 6.8 parts by mass, although this varies depending on the type of hydrofluoroether, its compatibility with the phenolic resin, and the foaming and curing conditions such as the foaming temperature and residence time during foam production.

[0021] Hydrofluoroethers are thought to act as bubble nuclei in phenolic resins, increasing the number of bubbles in the foamed phenolic resin composition. This is thought to reduce the average bubble diameter of the phenolic resin foam, suppress radiant heat conduction, and lower the thermal conductivity of the phenolic resin foam. The order in which the phenolic resin composition, blowing agent, and hydrofluoroether are mixed is not particularly limited, but it is more preferable to mix the hydrofluoroether into the phenolic resin composition before mixing in the blowing agent, or to mix the hydrofluoroether and blowing agent into the phenolic resin composition simultaneously. If the hydrofluoroether is mixed into the phenolic resin composition after the blowing agent, or if a mixture of hydrofluoroether and blowing agent is mixed in advance and then mixed into the phenolic resin composition, the hydrofluoroether may act as a bubble nucleus itself, but may also adsorb to bubbles that are already growing, inhibiting bubble growth. This raises concerns about a decrease in the closed-cell ratio. The mixing method is not particularly limited as long as the hydrofluoroether can be uniformly dispersed in the phenolic resin or phenolic resin composition. Furthermore, because hydrofluoroethers contain oxygen atoms and alkyl groups within their molecules, they have a shorter atmospheric lifetime compared to perfluoroalkanes, resulting in a relatively low global warming potential and thus a lower environmental impact. In addition, the presence of oxygen atoms within the molecule increases compatibility with phenolic resins, which is thought to improve the dispersibility of hydrofluoroethers in phenolic resins and promote the formation of fine bubble nuclei. On the other hand, molecular chains consisting only of carbon and fluorine in hydrofluoroethers tend to have a longer atmospheric lifetime as they lengthen, potentially increasing the GWP. Therefore, from an environmental perspective, it is preferable that molecular chains consisting only of carbon and fluorine are not long. Also, since hydrofluoroethers are flame retardants, it is thought that the higher the content of hydrofluoroethers in phenolic resin foams, the less flammable the phenolic resin foam becomes.

[0022] The hydrofluoroether in (Equation 2) is C a H b F c A group represented by C x Hy F z It must be an ether with the group represented by C. a H b F c The number of carbon atoms in the group represented by , i.e., the value of a, must be 2 to 7, and preferably 2 to 6, from the viewpoint of the boiling point of the hydrofluoroether. a H b F c The group represented by is a hydrocarbon group in which some or all of the hydrogen atoms are replaced with fluorine, preferably with a small number of hydrogen atoms, and the value of b must be between 0 and 3, preferably 0 or 1, and particularly preferably 0. x H y F z The number of carbon atoms in the group represented by , i.e., the value of x, must be 1 to 3, and preferably 1 to 2, from the viewpoint of the boiling point of the hydrofluoroether. x H y F z The group represented by is a hydrocarbon group or a group in which part of the hydrocarbon is substituted with fluorine, preferably with a small number of fluorine atoms, and preferably the value of z is 0 to 3. When the value of hydrofluoroether a is 7 or less and the value of x is 3 or less, the boiling point is sufficiently low, and the proportion of hydrofluoroether remaining as droplets in the foam is small, so the increase in heat conduction due to droplets can be suppressed. The hydrofluoroether of (Equation 2) is C with a small number of hydrogen atoms. a H b F c A group represented by and C with a small number of fluorine atoms x H y F z The presence of this group is thought to improve the dispersibility of the hydrofluoroether in the resin and promote the formation of fine bubble nuclei. Furthermore, it is preferable that a≧x, and more preferable that a>x.

[0023] Hydrofluoroethers of formula 2 that are preferably used in the present invention include methyl perfluoropropyl ether, methyl nonafluorobutyl ether, methyl nonafluoroisobutyl ether, ethyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether. These hydrofluoroethers may be used individually or in combination of two or more types.

[0024] The phenolic resin foam according to the present invention shows an improved compressive strength compared to phenolic resin foam without added hydrofluoroether. This is because the addition of hydrofluoroether reduces the size of the air bubbles, resulting in a greater number of air bubble walls aligned in the compression direction compared to phenolic resin foam without hydrofluoroether, thus increasing the resistance force. In addition, it reduces the number of voids that serve as fracture initiation points.

[0025] Furthermore, in this embodiment, the appearance is improved compared to phenolic resin foam without added hydrofluoroether. This is because the addition of hydrofluoroether not only reduces the size of the bubbles but also lowers the rate of void formation and tends to make the bubble size more uniform in the thickness direction, thus eliminating color unevenness in the foam.

[0026] The average bubble diameter of the phenolic resin foam in the present invention is preferably 70 μm to 180 μm, more preferably 70 μm to 170 μm, even more preferably 70 μm to 150 μm, and most preferably 70 μm to 135 μm. When the average bubble diameter is 70 μm or more, the increase in thermal conductivity due to heat conduction in the phenolic resin portion, which increases as the bubble diameter decreases, can be suppressed. Conversely, when the bubble diameter is 180 μm or less, heat conduction by radiation is small, and the increase in thermal conductivity can be suppressed. The average bubble diameter of the phenolic resin foam can be adjusted to a desired value by changing, for example, the amount of hydrofluoroether added, the amount of solid foaming nucleating agent added, the temperature of the foamable phenolic resin composition, the timing of pre-molding in the process of extruding the mixed foamable phenolic resin composition onto the lower surface material, as well as the amount of foaming agent and acidic curing agent added, and curing conditions such as temperature and residence time.

[0027] The phenolic resin foam of the present invention can be used with hydrofluoroolefins, hydrocarbons, and chlorinated hydrocarbons individually or in combination of two or more of these as foaming agents.

[0028] Hydrofluoroolefins generally have low thermal conductivity, and when used as a foaming agent, they are preferred because they yield phenolic resin foams with low thermal conductivity. Hydrofluoroolefins include chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins. In this invention, chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins can also be used in combination.

[0029] Examples of chlorinated hydrofluoroolefins include (Z)-1-Chloro-2,3,3,3-Tetrafluoropropene (HCFO-1224yd(Z)), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd, for example, the E-isomer (HCFO-1233zd(E)), manufactured by Honeywell Japan Co., Ltd., product name: Solstice(trademark) LBA), and 1,1,2-trichloro-3,3,3-trifluoropropene ( HCFO-1213xa), 1,2-dichloro-3,3,3-trifluoropropene (HCFO-1223xd), 1,1-dichloro-3,3,3-trifluoropropene (HCFO-1223za), 1-chloro-1,3,3,3-tetrafluoropropene (HCFO-1224zb), 2,3,3-trichloro-3-fluoropropene (HCFO-1231xf), 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf), 2 -Chloro-1,1,3-trifluoropropene (HCFO-1233xc), 2-Chloro-1,3,3-trifluoropropene (HCFO-1233xe), 2-Chloro-3,3,3-trifluoropropene (HCFO-1233xf), 1-Chloro-1,2,3-trifluoropropene (HCFO-1233yb), 3-Chloro-1,1,3-trifluoropropene (HCFO-1233yc), 1-Chloro-2,3,3-trifluoropropene (H Examples include (HCFO-1233yd), 3-chloro-1,2,3-trifluoropropene (HCFO-1233ye), 3-chloro-2,3,3-trifluoropropene (HCFO-1233yf), 1-chloro-1,3,3-trifluoropropene (HCFO-1233zb), and 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd). One or a mixture of these stereoisomers, i.e., the E or Z isomer, can be used. Furthermore, (E)-1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd(E)) can also be used. In this invention, two or more of these chlorinated hydrofluoroolefins can also be used in mixture form.

[0030] Examples of non-chlorinated hydrofluoroolefins include 1,3,3,3-tetrafluoropropane-1-ene (HFO-1234ze, e.g., the E-isomer (HFO-1234ze(E)), manufactured by Honeywell Japan Co., Ltd., product name: Solstice(trademark)ze), 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz, e.g., the Z-isomer (HFO-1336mzz(Z)), manufactured by Chemours K.K., Opteon(trademark) 1100), and 2,3,3,3 Examples include -tetrafluoro-1-propene (HFO-1234yf), 1,1,3,3,3-pentafluoropropene (HFO-1225zc), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 3,3,3-trifluoropropene (HFO-1243zf), and 1,1,1,4,4,5,5,5-octafluoro-2-pentene (HFO-1438mzz). One or a mixture of these stereoisomers, i.e., the E-form or the Z-form, can be used. In this invention, two or more of these non-chlorinated hydrofluoroolefins can also be used in mixture form.

[0031] Preferred hydrocarbons are cyclic or chain-like alkanes, alkenes, and alkynes having 3 to 7 carbon atoms. Specifically, examples include n-butane, isobutane, cyclobutane, n-pentane, isopentane, cyclopentane, neopentane, n-hexane, isohexane, 2,2-dimethylbutane, 2,3-dimethylbutane, cyclohexane, etc. Among these, pentanes (n-pentane, isopentane, cyclopentane, neopentane) and butanes (n-butane, isobutane, cyclobutane) are preferred. In this invention, two or more of these hydrocarbons can also be used in mixtures. Examples of mixtures include n-pentane and n-butane, isobutane and isopentane, n-butane and isopentane, isobutane and n-pentane, cyclopentane and n-butane, cyclopentane and isobutane, etc.

[0032] As chlorinated hydrocarbons, linear or branched chlorinated aliphatic hydrocarbons having 2 to 5 carbon atoms are preferably used. The number of bonded chlorine atoms is preferably 1 to 4, and examples include dichloroethane, propyl chloride, 2-chloropropane, butyl chloride, isobutyl chloride, pentyl chloride, and isopentyl chloride. Of these, propyl chloride and 2-chloropropane, which are chloropropanes, are more preferably used. In the present invention, two or more of these chlorinated hydrocarbons can also be used in combination.

[0033] Furthermore, other blowing agents are not particularly limited and include, for example, chemical blowing agents such as sodium bicarbonate, sodium carbonate, calcium carbonate, magnesium carbonate, azodicarboxylic acid amide, azobisisobutyronitrile, barium azodicarboxylic acid, N,N'-dinitrosopentamethylenetetramine, p,p'-oxybisbenzenesulfonyl hydrazide, and trihydrazinotriazine. These blowing agents may be used individually or in combination of two or more.

[0034] The amount of foaming agent in a phenol resin composition varies depending on the type of foaming agent, the compatibility of the foaming agent with the phenol resin, the temperature, and the conditions for foaming and curing, such as the residence time. Therefore, it can be arbitrarily determined depending on the desired density of the phenol resin foam and the foaming conditions, but it is preferably 3.0 to 20 parts by mass, more preferably 4.0 to 18 parts by mass, even more preferably 5.0 to 16 parts by mass, and most preferably 6.0 to 15 parts by mass per 100 parts by mass of the phenol resin composition. When the amount of foaming agent per 100 parts by mass of the phenol resin composition is 3.0 parts by mass or more, the densification of the resin foam can be suppressed. Furthermore, when the amount of foaming agent per 100 parts by mass of the phenol resin composition is 20 parts by mass or less, it becomes easier to suppress the decrease in mechanical strength such as compressive strength and the decrease in the closed-cell ratio due to the cell walls becoming more prone to breaking, which can be caused by the low density of the phenol resin foam, and the increase in thermal conductivity can be suppressed.

[0035] In this embodiment, a foaming nucleating agent may be used in the production of the phenolic resin foam. As the foaming nucleating agent, gaseous foaming nucleating agents such as nitrogen, helium, and argon, which have a boiling point 50°C or more lower than the foaming agent, can be added. In addition, solid foaming nucleating agents such as inorganic powders such as aluminum hydroxide powder, aluminum oxide powder, calcium carbonate powder, talc, molten clay (kaolin), silica powder, silica sand, mica, calcium silicate powder, wollastonite, glass powder, glass beads, fly ash, silica fume, gypsum powder, borax, slag powder, alumina cement, and Portland cement, as well as organic powders such as pulverized phenolic resin foam powder, can also be added. These may be used individually, or two or more types may be used in combination, without distinction between gaseous and solid. The timing of adding the foaming nucleating agent can be arbitrarily determined as long as it is supplied into the mixer that mixes the phenolic resin composition.

[0036] The amount of solid foaming agent added is preferably 3.0% by mass or more and 10.0% by mass or less, and more preferably 3.0% by mass or more and 8.0% by mass or less, per 100 parts by mass of the phenol resin composition. Adding 3.0% by mass or more of the solid foaming agent makes it easier to suppress the seepage of the foaming phenol resin composition from the surface material. Furthermore, adding 10.0% by mass or less of the solid foaming agent makes it easier to suppress the emission of foaming agents with low boiling points.

[0037] The density of the phenolic resin foam of the present invention may be adjusted to a desired density depending on the intended use of the foam, but is preferably 10 kg / m³. 3 More than 70kg / m 3 The following is more preferable: 20 kg / m 3 More than 55kg / m 3 The following is more preferably 22 kg / m 3 More than 50kg / m 3 The following is most preferably 24 kg / m 3 More than 45kg / m 3 The following is true: Density is 10 kg / m³ 3In the above case, the decrease in mechanical strength such as compressive strength and the decrease in surface brittleness that tend to occur due to low density are small, and sufficient strength for practical use can be maintained. 3 In the following cases, the concern that the thermal conductivity will increase due to the heat transfer of the resin portion, which is larger due to the high density, is reduced. The density of the phenolic resin foam can be adjusted by adjusting the filling ratio of the foaming agent into the phenolic resin foam, and can be adjusted to the desired value mainly by changing the amount of foaming agent added to the phenolic resin composition, the temperature of the foamed phenolic resin composition, the timing of pre-molding in the process of extruding the mixed foamed phenolic resin composition, as well as the amount of foaming nucleating agent added, the amount of acidic curing agent added, and curing conditions such as temperature and residence time.

[0038] The phenolic resin foam of the present invention preferably has a closed-cell ratio of 80% or more, more preferably 85% or more, even more preferably 90% or more, and most preferably 92% or more. When the closed-cell ratio is 80% or more, the increase in thermal conductivity due to the displacement of air by the blowing agent in the phenolic resin foam can be suppressed. This effect is greater the higher the closed-cell ratio. The closed-cell ratio of the phenolic resin foam can be adjusted to a desired value by changing, for example, the amount of foaming nucleating agent added, the amount of blowing agent added, and the amount of acid curing agent.

[0039] In this embodiment, the phenolic resin foam has a thermal conductivity at 23°C of preferably 0.0211 W / (m·K) or less, more preferably 0.0200 W / (m·K) or less, even more preferably 0.0180 W / (m·K) or less, and most preferably 0.0175 W / (m·K) or less.

[0040] In this embodiment, the void ratio of the phenolic resin foam is preferably 0.5% or less. A void ratio of 0.5% or less makes it less likely to cause a decrease in compressive strength in the thickness direction, and the voids are within a range where they are not noticeable in appearance. The void ratio can be adjusted by the amount of hydrofluoroether, curing conditions such as temperature and residence time, etc. In this invention, the void ratio is determined by cutting a cross-section parallel to the thickness direction of the resin foam, measuring the voids present in that cross-section using a method described later, and setting the area of ​​each void to 2.0 mm². 2 The above-mentioned elements are defined as voids, and the void ratio is defined as the value obtained by dividing the total area of ​​all voids on the cross-section by the cross-sectional area.

[0041] <Phenolic resin foam laminate> The phenolic resin foam laminate in this embodiment is a laminate having a surface material on at least one of the phenolic resin foam's surface and the back surface of that surface. In this embodiment, "thickness direction" refers to the dimension of the shortest of the three sides of the phenolic resin foam laminate, and is typically the direction in which the foamable phenolic resin composition on the lower surface material foams and grows during the manufacturing of the phenolic resin foam laminate.

[0042] Furthermore, phenolic resin foam laminates can be used on their own or joined to external components for various applications. Examples of external components include board-like materials, sheet-like / film-like materials, and combinations thereof. Suitable board-like materials include ordinary plywood, structural plywood, particleboard, and wood-based boards such as OSB, wood wool cement board, wood chip cement board, gypsum board, flexible board, medium-density fiberboard, calcium silicate board, magnesium silicate board, and volcanic glass composite board. Suitable sheet-like / film-like materials include polyester nonwoven fabric, polypropylene nonwoven fabric, inorganic-filled glass fiber nonwoven fabric, glass fiber nonwoven fabric, paper, calcium carbonate paper, polyethylene-processed paper, polyethylene film, plastic-based moisture-proof film, asphalt waterproof paper, and aluminum foil (perforated / non-perforated).

[0043] The method for producing phenolic resin foam will be explained in more detail below.

[0044] <Raw materials for phenolic resin foam laminates> As the phenolic resin, a resol-type phenolic resin synthesized from alkali metal hydroxides or alkaline earth metal hydroxides is used. The resol-type phenolic resin is synthesized by heating phenols and aldehydes as raw materials with an alkaline catalyst in a temperature range of 40 to 100°C. In addition, additives such as urea may be added during or after the synthesis of the resol-type phenolic resin as needed. When adding urea, it is more preferable to mix urea that has been methylolated with an alkaline catalyst beforehand with the resol-type phenolic resin. The synthesized resol-type phenolic resin usually contains excess moisture, so the moisture content is adjusted to a level suitable for foaming during foaming. In addition, aliphatic hydrocarbons or high-boiling point alicyclic hydrocarbons, or mixtures thereof, viscosity-adjusting diluents such as ethylene glycol and diethylene glycol, and other additives such as dicyandiamide and melamine may be added to the phenolic resin as needed.

[0045] The starting molar ratio of phenols to aldehydes during the synthesis of phenolic resins is preferably in the range of 1:1 to 1:4.5, and more preferably in the range of 1:1.5 to 1:2.5.

[0046] In this embodiment, the phenols preferably used in the synthesis of phenolic resins are phenol itself and other phenols. Examples of other phenols include resorcinol, catechol, o-, m- and p-cresol, xylenols, ethylphenols, and p-tert-butylphenol. Dinuclear phenols can also be used.

[0047] Furthermore, the aldehydes can be any compounds that can serve as an aldehyde source, and it is preferable to use formaldehyde itself, paraformaldehyde which can be used by depolymerization, and other aldehydes or their derivatives. Examples of other aldehydes include glyoxal, acetaldehyde, chloral, furfural, and benzaldehyde.

[0048] The mass-average molecular weight of the phenolic resin is preferably 300 or more, more preferably 400 or more, and even more preferably 450 or more. Furthermore, it is preferably 2,500 or less, more preferably 2,200 or less, even more preferably 2,050 or less, and most preferably 1,900 or less. When the mass-average molecular weight of the phenolic resin is 300 or more, runaway reactions due to the reaction heat of the curing reaction are less likely to occur, and foam molding can be performed using the reaction heat, resulting in good energy efficiency. Also, when the mass-average molecular weight is 2,500 or less, the reaction heat of the polymerization reaction is low, making it easier to form small bubbles. Because the resin is less likely to harden in equipment upstream of the board molding process, piping is less likely to become contaminated, and continuous operation for long periods is possible. The mass-average molecular weight of the phenolic resin can be measured using the method described in the examples of this specification.

[0049] The viscosity of the phenolic resin composition at 40°C is preferably 5,000 mPa·s to 100,000 mPa·s, more preferably 7,000 mPa·s to 50,000 mPa·s, and even more preferably 9,000 mPa·s to 40,000 mPa·s. Furthermore, the moisture content of the phenolic resin and the phenolic resin composition is preferably 1.5% by mass to 20% by mass.

[0050] The surfactant, hydrofluoroether, foaming agent, and foaming nucleating agent may be added to the phenol resin composition beforehand or added simultaneously with the acid curing agent. However, it is preferable to add the hydrofluoroether before or at the same time as the foaming agent.

[0051] As surfactants, those commonly used in the production of phenolic resin foams can be used, but nonionic surfactants are particularly effective. For example, alkylene oxides, which are copolymers of ethylene oxide and propylene oxide, condensates of alkylene oxide and castor oil, condensation products of alkylene oxide and alkylphenols such as nonylphenol and dodecylphenol, polyoxyethylene alkyl ethers with 14 to 22 carbon atoms in the alkyl ether portion, fatty acid esters such as polyoxyethylene fatty acid esters, silicone compounds such as polydimethylsiloxane, and polyalcohols are preferred. These surfactants may be used alone or in combination of two or more. There are no particular restrictions on the amount used, but it is preferably used in the range of 0.3 parts by mass to 10 parts by mass per 100 parts by mass of phenolic resin.

[0052] The acidic curing agent can be any acidic curing agent capable of curing the phenol resin composition, and contains an organic acid as the acid component. Preferred organic acids are aryl sulfonic acid or their anhydrides. Examples of aryl sulfonic acid and its anhydrides include toluenesulfonic acid, xylenesulfonic acid, phenolsulfonic acid, substituted phenolsulfonic acid, xylenolsulfonic acid, substituted xylenolsulfonic acid, dodecylbenzenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, and their anhydrides. These may be used individually or in combination of two or more. In this embodiment, resorcinol, cresol, saligenin (o-methylolphenol), and p-methylolphenol may be added as curing aids. Furthermore, these acidic curing agents may be diluted with solvents such as ethylene glycol and diethylene glycol.

[0053] The amount of acidic curing agent used varies depending on the type. When using a mixture of 80% by mass xylene sulfonic acid and 20% by mass diethylene glycol, it is preferably used in amounts of 6 to 20 parts by mass, more preferably 8 to 15 parts by mass, and most preferably 11 to 13 parts by mass, per 100 parts by mass of the phenol resin composition.

[0054] A flexible surface material is used as the surface material disposed on at least one side of the phenolic resin foam and the back surface of that side. The flexible surface material used is preferably a nonwoven or woven fabric whose main components are polyester, polypropylene, and nylon, paper such as kraft paper, glass fiber blended paper, calcium hydroxide paper, aluminum hydroxide paper, and magnesium silicate paper, or an inorganic fiber nonwoven fabric such as glass fiber nonwoven fabric, and these may be used in mixture (or laminate) form. When the surface material is peeled off from the resulting phenolic resin foam laminate and only the base material is used, inexpensive paper that can be discarded after peeling is preferred. These surface materials are usually provided in roll form. Furthermore, the flexible surface material may be one which has been kneaded with additives such as flame retardants. The method of bonding the surface material and the phenolic resin foam is not particularly limited, and adhesives such as epoxy resin may be used. However, from the standpoint of manufacturing costs and preventing the manufacturing process from becoming complicated, it is preferable that the bonding is achieved solely by the adhesive force generated when the foamed phenolic resin composition heat-cures on the surface material surface.

[0055] <Method for manufacturing phenolic resin foam laminates> A continuous manufacturing method is used for producing phenolic resin foam laminates, comprising a mixing step of mixing the above-mentioned foamable phenolic resin composition in a mixer, a dispensing step of dispensing the mixed foamable phenolic resin composition onto a bottom surface material, and a foam laminate manufacturing step of producing a phenolic resin foam laminate from the foamable phenolic resin composition dispensed onto the bottom surface material. It is also possible to employ a batch method using a mold that performs each step in stages.

[0056] In the continuous manufacturing method, the phenolic resin composition extruded onto the lower surface material is covered with the upper surface material, then pre-formed by leveling from above and below while foaming and curing, and then fully molded into a plate shape while continuing foaming and curing. In the continuous manufacturing method, various methods can be used for pre-forming and full molding depending on the manufacturing purpose, such as using a slat-type double conveyor, using metal rolls or steel plates, or using a combination of these. Of these, for example, when molding using a slat-type double conveyor, the foamed phenolic resin composition covered with upper and lower surface materials is continuously guided into the slat-type double conveyor, and then pressure is applied from above and below while heating, allowing it to be foamed and cured to a predetermined thickness and molded into a plate shape. The temperature of the foamed phenolic resin composition when extruded onto the lower surface material depends on the boiling point of the foaming agent, but is generally preferably 32°C to 45°C. If the temperature of the foamed phenolic resin composition is 32°C or higher, the foamed phenolic resin composition will foam more easily in the initial stages, making it easier to suppress the seepage of the foamed phenolic resin composition from the lower surface material. On the other hand, if the temperature of the foamed phenolic resin composition is 45°C or lower, even when using a foaming agent with a low boiling point, it becomes easier to suppress evaporation, making it easier to prevent a decrease in foaming efficiency and an increase in thermal conductivity due to the coarsening of the bubble diameter. The temperature of the foamed phenolic resin composition discharged onto the lower surface material can be controlled by adjusting the temperature and flow rate of the water used to mix the various compositions, as well as the rotation speed.

[0057] <Preforming process> The heating temperature control conditions for the process of pre-forming the foamable phenolic resin composition extruded onto the lower surface material while simultaneously foaming and curing it on the upper surface material are preferably 30°C to 80°C. A temperature of 30°C or higher facilitates the promotion of foaming during the pre-forming process and also accelerates curing. Furthermore, a temperature of 80°C or lower reduces the impact of internal heat generation near the center in the thickness direction, preventing the center temperature from rising too high and suppressing a decrease in the closed-cell ratio. To efficiently promote curing while suppressing the decrease in the closed-cell ratio due to internal heat generation near the center in the thickness direction during foaming and curing of the foamable phenolic resin composition, it is important to provide a pre-forming process followed by a main molding process and a post-curing process, gradually increasing the temperature.

[0058] <Main molding process> The heating temperature control conditions for the main molding process following the pre-forming process are preferably between 65°C and 100°C. In this section, the main molding can be performed using an endless steel belt type double conveyor, a slat type double conveyor, or rolls. Furthermore, since the residence time in this molding process is the main process for foaming and curing reactions, it is preferable to set it between 5 minutes and 2 hours. A residence time of 5 minutes or more allows for sufficient promotion of foaming and curing. A residence time of 2 hours or less increases the production efficiency of phenolic resin foam laminates. When using conveyors, it is desirable that the temperature difference between the upper and lower conveyors be less than 4°C.

[0059] <Post-curing process> After heating and temperature control through the pre-forming and main molding processes, a post-curing process is applied. The temperature of the post-curing process is preferably between 90°C and 120°C. A temperature of 90°C or higher facilitates the release of moisture from the foam board, while a temperature of 120°C or lower suppresses a decrease in the closed-cell ratio of the product and allows for the maintenance of low thermal conductivity for a long period. By providing a temperature-controlled section in the post-curing process, moisture in the foamed phenolic resin composition can be released after final molding. [Examples]

[0060] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0061] <Synthesis of phenolic resin> 3,500 kg of 52% by mass formaldehyde aqueous solution (52% by mass formalin) and 2,510 kg of 99% by mass phenol (containing water as an impurity) were charged into the reactor. The mixture was stirred using a propeller-type stirrer, and the internal liquid temperature of the reactor was adjusted to 40°C using a temperature controller. Next, the temperature was raised while adding a 48% by mass sodium hydroxide aqueous solution to carry out the reaction. The Ostwald viscosity of the reaction solution was 110 centistokes (= 110 × 10⁻¹⁰). -6 m 2 When the reaction reached a value of 1 / s (measured at 25°C), the reaction mixture was cooled and 398 kg of urea was added. The reaction mixture was then cooled to 30°C and the pH was neutralized to 6.4 with a 50% by mass aqueous solution of p-toluenesulfonic acid monohydrate.

[0062] This reaction solution was concentrated at 60°C to obtain phenol resin A. The mass-average molecular weight and viscosity at 40°C of phenol resin A were measured by the following methods, and the mass-average molecular weight was 1,300 and the viscosity at 40°C was 9,730 mPa·s.

[0063] <Mass-average molecular weight of phenolic resin> Gel permeation chromatography (GPC) measurements were performed under the following conditions, and the mass-average molecular weight Mw of the phenolic resin was determined from the calibration curve obtained using the standard substances (standard polystyrene, 2-hydroxybenzyl alcohol, and phenol) shown below. Pre-processing: Approximately 10 mg of phenolic resin was dissolved in 1 ml of N,N-dimethylformamide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., for high-performance liquid chromatography), and the solution was filtered through a 0.2 μm membrane filter and used as the measurement solution. Measurement conditions: Measurement device: Shodex System21 (manufactured by Showa Denko Corporation) Column: Shodex Asahipak GF-310HQ (7.5mm I.D. × 30cm) Eluent: 0.1% by mass of lithium bromide was dissolved in N,N-dimethylformamide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., for high-performance liquid chromatography) and used. Flow rate: 0.6ml / min Detector: RI detector Column temperature: 40℃ Standard materials: Standard polystyrene (Shodex STANDARD SL-105, manufactured by Showa Denko K.K.), 2-hydroxybenzyl alcohol (Sigma-Aldrich, 99% grade), phenol (Kanto Chemical Co., Ltd., special grade)

[0064] <Viscosity measurement of phenolic resin> A rotational viscometer (BrookField metek, DVNXHBCBG model, rotor part CPA-52Z) was used to measure the viscosity of phenolic resin after stabilizing 0.5 ml of phenolic resin at 40°C for 6 minutes.

[0065] (Example 1) To 100 parts by mass of phenol resin A, 3.0 parts by mass of a composition containing 50% each of ethylene oxide-propylene oxide block copolymer and polyoxyethylene dodecylphenyl ether as surfactants was mixed. This was designated as the phenol resin composition. Phenolic resin foam powder was added as a foaming nucleating agent at a concentration of 4.0% by mass to the phenol resin composition containing the surfactants. The viscosity of the phenol resin composition after kneading the phenolic resin foam powder at 40°C was 22,000 mPa·s. In addition, to 100 parts by mass of the above phenol resin composition, 3.0 parts by mass of 3M Novec® 7000 (manufactured by 3M) as a hydrofluoroether, 13 parts by mass of HCFO-1233zd(E) as a foaming agent, and 13 parts by mass of a composition consisting of a mixture of 80% by mass of xylene sulfonic acid and 20% by mass of diethylene glycol as an acid curing agent were added, and the mixture was supplied to a variable-speed mixing head heated to 17°C. The phenolic resin foam powder used here was obtained by grinding phenolic resin foam (Neomafoam manufactured by Asahi Kasei Building Materials Corporation) using the same procedure as in Example 1 of Japanese Patent Application Publication No. 2008-024868 (average particle size 28 μm, bulk density 181 kg / m³). 3The phenolic resin composition was kneaded with the hydrofluoroether, blowing agent, and acidic curing agent in a twin-screw extruder before the addition of the hydrofluoroether, blowing agent, and acidic curing agent. Subsequently, the hydrofluoroether, blowing agent, and acidic curing agent were mixed in a mixer, and the resulting foamy phenolic resin composition was distributed via a multi-port distribution pipe and supplied onto a moving lower surface material. The mixer used was the one disclosed in Figure 1 of Japanese Patent Application Publication No. 10-225993. Specifically, the mixer had an inlet for the phenolic resin composition containing the solid foaming nucleating agent, an inlet for the hydrofluoroether, and an inlet for the blowing agent arranged in order from top to bottom adjacently on the upper side of the mixer, and an inlet for the acidic curing agent on the side near the center of the stirring section where the rotor stirs. The section after the stirring section is connected to a nozzle for discharging the foamy phenolic resin composition. In other words, the mixer is composed of a mixing section (preliminary stage) up to the acidic curing agent inlet, a mixing section (later stage) from the acidic curing agent inlet to the end of stirring, and a distribution section from the end of stirring to the nozzle. The distribution unit has multiple nozzles at its tip and is designed to ensure uniform distribution of the mixed foamed phenolic resin composition. Furthermore, the distribution unit has a jacketed structure that allows for sufficient heat exchange with temperature-controlled water, and the temperature of the temperature-controlled water in the distribution unit was set to 17°C. In addition, a thermocouple was installed at the discharge port of the multi-port distribution pipe to detect the temperature of the foamed phenolic resin composition, and the rotation speed of the mixer was set to 500 rpm. At this time, the temperature of the foamed phenolic resin composition discharged onto the lower surface material was 34°C. The foamed phenolic resin composition supplied onto the lower surface material was introduced into a pre-forming process that was temperature-controlled to 40°C, and after 30 seconds, pre-forming was performed from above the upper surface material using a free roller. The residence time for this process was set to 5 minutes. Subsequently, the material was sandwiched between two surface materials and introduced into a slat-type double conveyor heated to 69°C (main molding process). After curing for 15 minutes, it was cured at 100°C for 9 minutes, followed by curing at 110°C for 2 hours (post-curing process) to obtain a phenolic resin foam laminate with a thickness of approximately 30 mm. The surface materials used for both the upper and lower surfaces were polyester nonwoven fabrics (Asahi Kasei Corporation's Eltas E05060, basis weight 60 g / m²). 2 This method was used. This manufacturing method is indicated as Manufacturing Method A in Table 2.

[0066] The properties of the obtained phenolic resin foam and phenolic resin foam laminate were evaluated using the following methods (identification and measurement of hydrofluoroether content in the phenolic resin foam, identification of blowing agent type, measurement of average cell diameter, measurement of density, measurement of thermal conductivity at 23°C, measurement of compressive strength in the thickness direction, evaluation of color unevenness and void ratio, and measurement of closed cell ratio).

[0067] <Identification and content measurement of hydrofluoroethers in phenolic resin foam, and identification of foaming agents> First, the retention times were determined under the following GC / MS measurement conditions using standard gases of hydrofluoroethers, hydrofluoroolefins, halogenated hydrocarbons, and hydrocarbons.

[0068] A 0.25 mg sample was cut from near the center of a phenolic resin foam and placed in a dedicated container. 10 ml of chloroform and 12 crushed glass beads were added. The sample was homogenized using an IKA ULTRA-TURRAX Tube Drive at 6000 rpm for 7-11 minutes while extracting the components into the chloroform. The extract was then filtered through a 0.45 μm filter and subjected to GC / MS measurement. Standard sample solutions of known concentrations were prepared by dissolving the target component in chloroform and subjected to GC / MS measurement under the same conditions as the sample.

[0069] Hydrofluoroethers, hydrofluoroolefins, halogenated hydrocarbons, and hydrocarbons were identified from pre-determined retention times and mass spectra. Separately, the detection sensitivity of each generated gas component was measured using standard gases, and the content of each substance was calculated from the detection area and detection sensitivity of each gas component obtained by GC / MS. From the content of each identified gas component, the hydrofluoroether content (percentage of phenolic resin foam by mass) and the content and molar mass of each blowing agent component were calculated.

[0070] (GC-MS measurement conditions) GC device: Agilent 6890 Column: DB1 (30m, 0.25mmφ, film thickness 0.25μm) Column temperature: 40°C (5 min) ~ (20°C / min heating) - 200°C Flow rate: 1mL / min Temperature at the pouring port: 320℃ Injection method: Split method (1 / 50) Sample injection volume: 1 μL MS equipment: JEOL AutoMass-SUN Interface temperature: 300℃ Ionization method: EI method 70 eV Measurement method: Scan Scan range: m / z = 20~600 Ion source temperature: 240℃

[0071] <Measurement of average bubble diameter in phenolic resin foam> The average bubble diameter was measured using the following method: Four photographs were taken using a scanning electron microscope magnified 50 times, focusing on bubbles approximately in the center of the thickness direction of the phenolic resin foam laminate and at a position approximately in the center relative to the front and back surfaces. Four straight lines, each 90 mm long (corresponding to 1,800 μm in the actual foam cross-section), were drawn on the resulting photographs, avoiding voids. The number of bubbles measured along each line was determined, and the average value of these numbers divided by 1,800 μm was used as the average bubble diameter.

[0072] <Measurement of density of phenolic resin foam> A 200mm square phenolic resin foam laminate was used as the sample. After removing the surface material from the sample, the mass and apparent volume were measured according to JIS K7222.

[0073] <Measurement of thermal conductivity of phenolic resin foam laminate at 23°C> In accordance with JIS A 1412-2:1999, the thermal conductivity in the thickness direction of a resin foam laminate was measured at a temperature of 23°C using the following method. The specific procedure is as follows.

[0074] A phenolic resin foam laminate was cut into 300 mm squares, and the specimens were placed in an atmosphere of 23±1°C and 50±2% humidity. The weight change over time was then measured every 24 hours, and the condition was checked and adjusted until the weight change after 24 hours was 0.2% by mass or less. The conditioned phenolic resin foam laminate specimens were then introduced into a thermal conductivity measuring device placed in the same atmosphere of 23±1°C and 50±2% humidity. If the thermal conductivity measuring device was not located in a controlled room of 23±1% and 50±2% humidity, the specimens, after being checked and adjusted in the aforementioned atmosphere, were quickly placed in a polyethylene bag, sealed, and removed within one hour for immediate measurement of thermal conductivity.

[0075] Thermal conductivity measurements were performed using a single test specimen and a measurement device (Eiko Seiki Co., Ltd., product name "HC-074 / FOX304"), under conditions of 13°C for the low-temperature plate and 33°C for the high-temperature plate.

[0076] <Measurement of compressive strength in the thickness direction of phenolic resin foam> After removing the facing material from the obtained phenolic resin foam laminate, the compressive strength in the thickness direction of the phenolic resin foam was measured in accordance with JIS K7220. However, the dimensions of the foam were set to 100 mm × 100 mm × 30 mm.

[0077] <Evaluation of color variations in phenolic resin foam> The cross-section of the phenolic resin foam in the thickness direction was visually observed. As a result, foams that showed visible variations in bubble diameter, other than voids, in a streaky or localized manner, resulting in an uneven appearance of color, were evaluated as having "color unevenness," while those that did not meet this criterion were evaluated as having "color unevenness."

[0078] <Evaluation of void ratio of phenolic resin foam> The phenolic resin foam was cut parallel to the front and back surfaces, approximately in the center of its thickness, and a 100mm x 150mm area was enlarged by 200% (area increased 4.0 times) and a color copy was made. Using transparent graph paper, at least 8 squares of 1mm x 1mm were created (2.0mm).2 The area of ​​the voids (as described above) was added up to calculate the area fraction, and the void ratio (%) (average value of 4 measurements) was used as the value. Phenolic resin foams with a void ratio of 0.5% or less were evaluated as "low," and those with a void ratio exceeding 0.5% were evaluated as "high."

[0079] <Measurement of closed-cell ratio in phenolic resin foam> At the center of the phenolic resin foam in the thickness direction, a 25mm cube is cut out as a sample using a cutting tool such as a band saw if the thickness of the resin foam is 25mm or more. If the thickness of the resin foam is less than 25mm, a rectangular parallelepiped with dimensions of 25mm in both length and width is cut out as a sample, retaining the thickness after removal of the facing material (if fibrous material derived from the facing material remains, or if there is facing material on the back side). Then, the sample volume V (cm³) is measured according to the standard usage method of an air-comparative hydrometer (Model 1000, manufactured by Tokyo Science Co., Ltd.). 3 The closed-cell ratio in the resin foam is calculated by subtracting the volume of the cell walls (W / ρ), which is calculated from the sample mass W (g) and the density ρ of the resin composition constituting the resin foam, from the sample volume V as shown in the following formula, and then multiplying this by the apparent volume Va (cm³) calculated from the outer dimensions of the sample. 3 This value is obtained by dividing by ( ), and is measured in accordance with ASTM D 2856 (Method C). The density of the phenolic resin composition was calculated as 1.27 kg / L. Closed cell ratio (%)=((VW / ρ) / Va)×100

[0080] (Example 2) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was replaced with 3M Novec® 7100 high-performance liquid (manufactured by 3M).

[0081] (Example 3) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was replaced with 3M Novec® 7200 high-performance liquid (manufactured by 3M).

[0082] (Example 4) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was replaced with 3M Novec® 7300 high-performance liquid (manufactured by 3M).

[0083] (Example 5) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was replaced with Asahi Clean® AE-3000 (manufactured by AGC Inc., purity 99% or higher).

[0084] (Example 6) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M Corporation) and the amount of hydrofluoroether added per 100 parts by mass of the phenol resin composition was set to 0.1 parts.

[0085] (Example 7) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M Corporation) and the amount of hydrofluoroether added per 100 parts by mass of the phenol resin composition was set to 6.5 parts.

[0086] (Example 8) A resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M Corporation) and HCFO-1224yd(Z) (manufactured by AGC Corporation) was added as a blowing agent in a quantity of 14 parts by mass.

[0087] (Example 9) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M), and the blowing agent was a mixture of 80% by mass of HCFO-1224yd(Z) (manufactured by AGC) and 20% by mass of cyclopentane, with the amount of mixed blowing agent added being 12 parts by mass.

[0088] (Example 10) A resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M Corporation) and cyclopentane was added as a blowing agent in a quantity of 6.3 parts by mass.

[0089] (Example 11) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M), HCFO-1224yd(Z) (manufactured by AGC) was used as the blowing agent, the amount of blowing agent added was set to 14 parts by mass, and the hydrofluoroether inlet was installed downstream of the mixer so that the hydrofluoroether was kneaded after the blowing agent. This manufacturing method is indicated as Manufacturing Method B in Table 2.

[0090] (Example 12) To 100 parts by mass of phenol resin A, 3.0 parts by mass of a composition containing 50% each of ethylene oxide-propylene oxide block copolymer and polyoxyethylene dodecylphenyl ether as surfactants was mixed. This was designated as the phenol resin composition. To 100 parts by mass of the phenol resin composition containing the above surfactants, 3.0 parts by mass of 3M Novec® 7200 (manufactured by 3M Corporation) was added as a hydrofluoroether to each poly cup. The mixture was kneaded using a cordless driver drill (Hi-Koki DS 10DAL) with a stirring rod attached. Then, 12 parts by mass of HCFO-1233zd(E) was added as a foaming agent, and the mixture was kneaded using the cordless driver drill while cooling the poly cups. In this case, no foaming nucleation agent was added, but the air incorporated during kneading acted as a foaming nucleation agent. The fact that the specified amounts of each component had been kneaded was confirmed by the change in the weight of the resin composition. Next, the poly cup containing the foamed phenolic resin composition was cooled in a refrigerator for 1 hour to confirm that the foamed phenolic resin composition was below 12°C. Then, 13 parts by mass of a composition consisting of a mixture of 80% by mass xylene sulfonic acid and 20% by mass diethylene glycol was added as an acid curing agent, and the mixture was kneaded for 2 minutes in an ice bath using a cordless driver drill. Next, the foamed phenolic resin composition was applied to the bottom surface of a metal frame (mold) with a spatula in an environment of 13°C. The amount of foamed phenolic resin composition applied was adjusted as appropriate so that the thickness would not exceed the metal frame (mold) after foaming. The metal frame (mold) used here was made of metal with a thickness of 2.0 mm, with an inner diameter of 300 mm x 300 mm x height of 30 mm, and the bottom surface had holes with a diameter of 5 mm punched at 1 mm intervals. Furthermore, polyester nonwoven fabric (Asahi Kasei Corporation Eltas E05060, basis weight 60 g / m²) was placed on the bottom surface. 2The phenolic resin composition was laid as the surface material. The time taken from mixing the foamed phenolic resin composition and the acidic curing agent to the completion of application was 5 minutes. Then, as the top plate, a plate larger than 300 mm x 300 mm with the same perforated specifications as the bottom surface was attached to the same surface material as the bottom surface of the metal frame (mold), and placed over the metal frame (mold) so that the surface material faced the foamed phenolic resin side, and the top plate was fixed to the metal frame (mold) with clips. This metal frame (mold) was placed in an oven heated to 85°C, a 25 kg weight heated to 85°C was placed on the center of the top plate of the metal frame (mold), and it was heated for 1 hour, and then cured at 105°C for another hour to obtain a phenolic resin foam laminate with a thickness of 30 mm. This manufacturing method is indicated as manufacturing method C in Table 2.

[0091] (Comparative Example 1) The resin foam was manufactured in exactly the same manner as in Example 1, except that it was changed to AMOLEA® AS-300 (manufactured by AGC, purity 99% or higher), which is a fluorine compound that does not fall under Formula 1.

[0092] (Comparative Example 2) The resin foam was manufactured in exactly the same manner as in Example 1, except that the hydrofluoroether was changed to Novec® 7200 (manufactured by 3M Corporation) and the amount of hydrofluoroether added to 100 parts by mass of the phenol resin composition was set to 7 parts.

[0093] (Comparative Example 3) The resin foam was manufactured in exactly the same manner as in Example 1, except that hydrofluoroether was not added.

[0094] (Comparative Example 4) The resin foam was manufactured in exactly the same manner as in Example 8, except that hydrofluoroether was not added.

[0095] (Comparative Example 5) The resin foam was manufactured in exactly the same manner as in Example 9, except that hydrofluoroether was not added.

[0096] (Comparative Example 6) The resin foam was manufactured in exactly the same manner as in Example 10, except that hydrofluoroether was not added.

[0097] (Comparative Example 7) The resin foam was manufactured in exactly the same manner as in Example 12, except that hydrofluoroether was not added.

[0098] Table 1 shows the types of hydrofluoroethers used in Examples 1-12 and Comparative Examples 1 and 2. The aforementioned measurement and evaluation tests were also performed on Examples 1-12 and Comparative Examples 1-7. The measurement and evaluation results are shown in Section 2.

[0099] [Table 1]

[0100] [Table 2] [Industrial applicability]

[0101] The phenolic resin foam and its laminate of this embodiment have small cell diameters, which may give them excellent thermal insulation properties. Furthermore, they exhibit improved appearance, such as voids and color unevenness, as well as reduced compressive strength, making them suitable for use in various locations requiring thermal insulation. Additionally, the raw materials are cheaper than those of conventional technologies, requiring less capital investment and resulting in a low GWP (Global Warming Potential), thus providing an environmentally friendly foam with a low environmental impact.

Claims

1. The hydrofluoroether represented by the following formula (Formula 1) is contained in an amount of 0.03 to 4.3% by mass relative to the phenolic resin foam. The foaming agent contains hydrofluoroolefin, The closed-cell ratio is 80% or more. A phenolic resin foam having an average cell diameter of 70 μm or more and 180 μm or less. (Equation 1): C ａ H ｂ F ｃ -O-C ｘ H ｙ F ｚ (However, a, b, c, x, y, z are integers, and 2 ≤ a ≤ 7, 0 ≤ b ≤ 3, c = 2a + 1 - b, b ≤ 2a + 1, 1 ≤ x ≤ 3, 2 ≤ y ≤ 7, z = 2 × x + 1 - y, y ≤ 2x + 1)

2. The phenol resin foam according to claim 1, wherein the hydrofluoroether represented by (Formula 1) is any of methyl perfluoropropyl ether, methyl nonafluorobutyl ether, methyl nonafluoroisobutyl ether, ethyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

3. The phenolic resin foam according to claim 1 or 2, wherein the foaming agent contains a hydrocarbon.

4. Density is 10 kg / m³ ３ More than 70kg / m ３ The phenolic resin foam according to claim 1 or 2, which is as follows:

5. The laminate of phenolic resin foam according to claim 1 or 2, wherein a surface material is provided on at least one of one side of the phenolic resin foam and the back surface of said side.

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