Phenolic foam and thermal insulation material comprising same

Abstract

The present invention relates to a phenolic foam and a thermal insulation material comprising same and, more specifically, to a phenolic foam in which chemical consumption of formaldehyde is induced during a foaming process while maintaining the heat resistance and physical properties of the phenolic foam to reduce a residual formaldehyde content, thereby securing eco-friendliness, and to a thermal insulation material comprising same.

Description

Phenolic foam and insulation material containing the same

[0001] The present invention relates to a phenolic foam and an insulating material containing the same, and more specifically, to a phenolic foam and an insulating material containing the same that can secure eco-friendliness by reducing the residual formaldehyde content by inducing chemical consumption of formaldehyde during the polymerization and foaming process while maintaining the heat resistance and physical properties of the foam by including a small amount of bisphenol A (BPA) together with a composition for polymerizing a phenolic foam, which has phenolic resin and formaldehyde as main components.

[0002] Phenolic foam is widely used as a high-performance thermal insulation and fire-resistant material in the construction, marine, and aerospace industries due to its excellent thermal insulation performance, superior fire resistance, and low smoke generation. Conventional phenolic foam is manufactured by foaming phenol-formaldehyde resins based primarily on phenol and formaldehyde. To ensure excellent thermal conductivity and compressive strength, the manufactured phenolic foam requires a rigid network structure, and typically, resins polymerized with an excess amount of formaldehyde are used for foaming. The use of an excessive amount of formaldehyde during the resin polymerization stage causes a problem in which a large amount of unreacted formaldehyde remains within the manufactured foam.

[0003] To improve this, conventional technologies (KR2008-0026605A, WO2019-030239 A1, etc.) have proposed methods to chemically absorb residual formaldehyde in the resin by adding various additives that adsorb or remove formaldehyde, such as urea, melamine, L-arginine, aminoguanidine bicarbonate, carbohydrazide, oxalyl dihydrazide, and adipic acid dihydrazide, or to suppress released formaldehyde by physically adsorbing it by applying various additives to the surface of the foam as a scavenger. However, since these methods are merely physical adsorption or chemical neutralization at the post-reaction stage, they do not serve as a fundamental solution to suppress the generation of formaldehyde itself or promote chemical consumption. Furthermore, when an excessive amount of adsorbent is added, side effects such as reduced foam stability, collapse of the cell structure, and reduced mechanical strength may occur. In particular, additives such as urea affect the foaming speed, thereby reducing efficiency in terms of production.

[0004] Therefore, there is a need to develop new compositions and manufacturing technologies that can fundamentally improve the problem of formaldehyde retention and emission while maintaining the unique thermal insulation performance and chemical stability of phenolic foam.

[0005] In order to solve the problems of the conventional technology described above, the present invention aims to provide a phenolic foam and an insulating material containing the same, which can fundamentally improve the problem of formaldehyde residue and emission occurring in phenolic foams and secure eco-friendliness without reducing the thermal insulation and mechanical strength of the foam.

[0006] The objectives of the present invention are not limited to those mentioned above, and other objectives and advantages of the present invention not mentioned may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0007] According to one aspect of the present invention, a phenolic foam can be provided, which is a cured product of a foaming composition comprising a phenolic resin, a foaming agent, and a curing agent, wherein the phenolic resin comprises a polymer of a mixture of a phenol monomer and bisphenol A and formaldehyde.

[0008] When the combined weight of the above phenol monomer and bisphenol A is 100% by weight, the bisphenol A can be mixed in an amount of 5 to 30% by weight.

[0009] The above phenolic foam may have an initial thermal conductivity of 0.022 W / m·K or less, measured by the plate heat flow meter method at an average temperature of 20℃.

[0010] The above phenolic foam may have a long-term thermal conductivity of 0.024 W / m·K or less when measured by the plate heat flow meter method at an average temperature of 20°C after being left in a 110°C environment for 14 days.

[0011] The above phenolic foam may have an independent cell ratio of 85% or more as measured according to ASTM D6226.

[0012] The reaction molar ratio (f / p value) of formaldehyde to the above phenol monomer can be greater than 1 and less than 2.5.

[0013] The above foaming composition may further include urea.

[0014] Urea may be included in an amount of 10 parts by weight or less per 100 parts by weight of the above phenolic resin.

[0015] The above phenol foam may have a compressive strength of 100 kPa or more as measured by the KS M ISO 844 measurement method.

[0016] The above phenol foam does not leach bisphenol A.

[0017] According to another aspect of the present invention, a method for manufacturing a phenolic foam can be provided, comprising: (S1) a step of polymerizing a phenolic resin; (S2) a step of manufacturing a foaming composition; and (S3) a step of filling the foaming composition into a sheet material.

[0018] The above step (S1) may be performed sequentially by: (S1-1) a step of liquefying phenol by raising the temperature of the polymerization step of the phenolic resin to a temperature condition of 40 to 80°C; (S1-2) a step of liquefying the mixture of phenol and bisphenol by mixing bisphenol A with the liquefied phenol; (S1-3) a step of adding an aqueous formaldehyde solution to the liquefied mixture of phenol and bisphenol and polymerizing under a temperature condition of 80 to 100°C; and (S1-4) a step of terminating the polymerization.

[0019] Urea can be further mixed in step (S1) or step (S2) above.

[0020] The above method for manufacturing the phenol foam may further include an aging step (S4) after step (S3).

[0021] According to another aspect of the present invention, an insulating material comprising the phenolic foam can be provided.

[0022] The phenolic foam according to the present invention introduces an appropriate amount of bisphenol A into the polymerization reaction of phenol and formaldehyde, thereby promoting the chemical consumption of formaldehyde compared to existing resins that do not use bisphenol A, significantly reducing the formaldehyde remaining or released in the final polymer and foam, while maintaining the existing rigid three-dimensional network structure, thus possessing excellent thermal insulation and mechanical strength.

[0023] In addition, the phenolic foam according to the present invention controls the fundamental generation stage of residual formaldehyde in the resin by directly reacting phenol and bisphenol A with formaldehyde in the reaction system, and forms a rigid structure within the final foam, thereby drastically reducing the formaldehyde finally released, and the use of an appropriate amount of bisphenol A ensures that bisphenol A leaching from the foam is not detected, thus providing excellent safety for the human body and the environment.

[0024] In addition to the effects described above, the effects of the present invention are described together with the details for implementing the invention below.

[0025] Figure 1 shows the total ion chromatogram (TIC) and extraction ion chromatography (EIC) result graphs of the phenol foam insulation material of the present invention, and the peaks derived from bisphenol A can be determined by observing the peaks that increase with the amount of bisphenol A added (horizontal axis: Retention time (min), vertical axis: Abundance (au)).

[0026] Figure 2 shows the mass spectrum results confirming the peak of the pyrolysis byproduct derived from bisphenol A (hereinafter referred to as the 'bisphenol A-derived peak') (horizontal axis: m / z, vertical axis: Abundance (au)).

[0027] Figure 3 shows the mass spectrum results confirming the peak of bisphenol A monomer (horizontal axis: m / z, vertical axis: Abundance (au)).

[0028] Figure 4 is the result of the detection test report for phenol, formaldehyde, and bisphenol A of Example 3 of the present invention.

[0029] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0030] Where terms such as “comprising,” “having,” “consisting of,” “arranging,” or “having” are used for a component in this specification, other parts may be added unless “only” is used. Where a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise.

[0031] In interpreting the components in this specification, they are interpreted to include an error range even if there is no separate explicit description.

[0032] In this specification, the standard for units is weight (wt) unless otherwise specifically stated. For example, if "%" is indicated, it is interpreted as weight % (weight%).

[0033] In this specification, viscosity is based on values ​​measured with a DV3T Brookfield viscometer (spindle cylinder type LV3 (63), 3 rpm, @25℃) unless otherwise specified.

[0034] The present invention will be described in more detail below.

[0035]

[0036] A phenol foam according to one embodiment of the present invention is a cured product of a foamable composition comprising a phenolic resin, a foaming agent, and a curing agent, wherein “phenolic resin” means a phenol-bisphenol A-formaldehyde copolymer obtained by chemically reacting a mixture of a phenol monomer and bisphenol A with formaldehyde.

[0037] Meanwhile, using a resol-type phenolic resin having a branched chemical structure is desirable for imparting a chemically dense three-dimensional network structure to the final foam. Such a structure has the effect of improving the thermal insulation performance and mechanical strength of the foam.

[0038] Since bisphenol compounds basically have a structure in which two phenol groups are already bonded, theoretically, they are expected to form branched structures more easily than phenol monomers during condensation and curing reactions with formaldehyde. However, despite this theoretical possibility, bisphenol has not been actually applied or popularized as a main monomer in the field of commercial phenol foam manufacturing.

[0039] The main reasons are as follows. First, bisphenols have lower chemical reactivity with formaldehyde compared to phenols, making it relatively difficult to completely react the monomers used in polymerization. This is attributed to the electronic effect caused by the isopropylidene group (-C(CH3)2-), which connects the two phenol nuclei of bisphenol, acting as an electron-donating group to reduce the reactivity of the ortho positions of both phenol groups. Additionally, since the isopropylidene group is a bulky substituent, it causes steric hindrance itself; furthermore, because it is already bonded to the para positions of both phenols, the reaction sites accessible to formaldehyde are limited.

[0040] Therefore, bisphenols are structurally less reactive than phenols, and as a result, there is a possibility that residual monomers may not be completely consumed even after polymerization. Since such residual monomers may cause problems in terms of the safety and environmental hazards of the final product, when bisphenol is used as the main raw material for phenol resin, optimization of reaction conditions and the addition of post-treatment processes are required.

[0041] In addition, there are disadvantages from a commercial and production perspective due to its much higher price and melting point compared to phenol. For these reasons, the use of BPA instead of phenol as a raw material for phenol resin used in phenol foam insulation has been extremely limited.

[0042] Despite the limitations of the prior art described above, the inventors have improved the process applicability of bisphenol A, which has a high melting point, from a commercial perspective by using a phenol monomer dissolved as the main component and dissolving a specific amount of bisphenol A together. Furthermore, they have enabled the three-dimensional network structure of the existing phenol resin to be maintained while chemically consuming all of the bisphenol A during the polymerization reaction process, and have confirmed that by adjusting the amounts of bisphenol A and urea to an appropriate range so that they act complementarily, the amount of formaldehyde emission can be drastically reduced while maintaining excellent initial and long-term thermal insulation properties of the final product.

[0043] In particular, by limiting the amount of bisphenol A, which exhibits formaldehyde reduction performance, to an optimal range, and simultaneously setting the urea content to correspond to this, an optimal point was secured that maximizes the formaldehyde reduction effect without the combination of the two components having a negative effect on the polymerization reaction and foaming characteristics. This also ensured cost efficiency.

[0044] Under conditions configured in this way, the addition of an appropriate amount of bisphenol A significantly reduces unreacted formaldehyde in the polymerized phenol resin, and the foam produced using the resin not only has low residual formaldehyde but also forms a rigid cell structure, which greatly reduces the release of formaldehyde. As a result, it was experimentally confirmed that a foam satisfying the formaldehyde emission rate standards required by strict environmental regulations can be obtained, and it was also confirmed that bisphenol A is not detected in the final product.

[0045] According to one example of the present invention, when the phenol monomer and bisphenol A are combined to make 100% by weight, the bisphenol A may be included in an amount of 5 to 30% by weight, and preferably in an amount of 7 to 20% by weight. If the bisphenol A is included in an amount less than 5% by weight, the chemical consumption of formaldehyde is not sufficiently achieved to a level similar to that of conventional resins using only phenol monomer and formaldehyde, and thus the desired excellent residual formaldehyde reduction effect cannot be obtained. Furthermore, if the bisphenol A is included in an amount exceeding 30% by weight, the aforementioned commercial inefficiency occurs, and at the same time, an environmental problem may arise in which unreacted bisphenol A remains in the final product.

[0046] According to one example of the present invention, a bisphenol A-derived component is detected in the phenol foam by thermal decomposition GC (Experimental Example 6). This allows for determining whether bisphenol A is used during the manufacture of the phenol foam and confirming the amount of bisphenol A mixed or used by detecting byproduct peaks by thermal decomposition analysis of a phenol foam manufactured by curing using a foaming composition, separate from the mixing of bisphenol A to manufacture a phenolic resin. Specifically, as described in detail in Experimental Example 6 below, the bisphenol A-derived peak can be confirmed by comparing the peaks observed after thermal decomposition analysis of a phenol foam manufactured by mixing bisphenol A with a phenol monomer and a phenol foam manufactured without mixing bisphenol A with a phenol monomer. Such bisphenol A-derived peaks are intended to confirm whether bisphenol A is used or the amount used during the process of manufacturing the foam, and are unrelated to the release of bisphenol A from the manufactured phenol foam (phenol foam). Although the phenol foam according to the present invention uses bisphenol A, no release of bisphenol A was detected when applied as an insulating material.

[0047] According to one example of the present invention, the reaction molar ratio (f / p value) for polymerizing by reacting a phenol monomer with formaldehyde may be in the range greater than 1 and less than 2.5, for example, in the range of 1.2 to 2.4, for example, in the range of 1.3 to 2.2, or for example, in the range of 1.4 to 2.0. By forming a phenolic resin with the above molar ratio, the curing reaction can be appropriately controlled and the physical properties of the phenolic foam can be secured, and the concentration of formaldehyde generated by unreacted and reversible reactions can be appropriately controlled. For example, if the content of formaldehyde is below the above range, there may be a problem in that thermal conductivity and mechanical properties are degraded. In addition, if the above range is exceeded, an excessive amount of unreacted formaldehyde is generated, reaction control during polymerization and curing is difficult, and it may cause problems such as an excessive amount of residual formaldehyde remaining in the final foam.

[0048] According to one example of the present invention, the foaming composition may further include urea. Urea can further contribute to the additional adsorption and stabilization of formaldehyde by reacting with a small amount of formaldehyde during the foaming reaction to form a stable methylol derivative. However, since the addition of an excessive amount of urea may lead to a decrease in the curing speed and bubble collapse, it may be included in an amount of 10 parts by weight or less per 100 parts by weight of the phenolic resin, for example, 8 parts by weight or less, for example, 6 parts by weight or less, and may be included in an amount of 1 part by weight or more to ensure the adsorption of formaldehyde. When urea is included within the above range, the effect of reducing residual formaldehyde and foaming stability can be simultaneously secured. In this case, the phenolic resin serving as the standard for the urea content refers to a phenolic resin polymerized and manufactured using a foaming composition containing urea.

[0049] Meanwhile, the urea contained in the foaming composition can be mixed after manufacturing the phenolic resin, and the urea can be mixed and polymerized when polymerizing the phenolic resin, and the urea addition (mixing) step can be changed depending on the process.

[0050] According to one example of the present invention, the blowing agent may include an aliphatic hydrocarbon having 1 to 8 carbon atoms. Generally, phenolic foams may include hydrofluoroolefin (HFO) compounds with excellent thermal conductivity to exhibit excellent thermal insulation. On the other hand, hydrofluoroolefin compounds have a low boiling point, making them difficult to handle during foam manufacturing. Furthermore, they may volatilize without being contained within the bubbles during the manufacturing process, which may lead to a decrease in physical properties relative to the input amount. The phenolic foam may include an aliphatic hydrocarbon having 1 to 8 carbon atoms as a blowing agent to improve physical properties such as compressive strength and brittleness, along with excellent thermal insulation.

[0051] For example, the phenol foam may include one aliphatic hydrocarbon selected from the group consisting of chlorinated, non-chlorinated aliphatic hydrocarbons and combinations thereof. Specifically, the hydrocarbon compound may include at least one selected from the group consisting of dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride, n-butane, isobutane, n-pentane, isopentane, cyclopentane, hexane, heptane, cyclopentane, and combinations thereof. The blowing agent may be included in an amount of 5 to 20 parts by weight, for example, 8 to 18 parts by weight, based on 100 parts by weight of the phenolic resin.

[0052] According to one example of the present invention, the curing agent may include one acid curing agent selected from the group consisting of toluene sulfonic acid, xylene sulfonic acid, benzene sulfonic acid, phenol sulfonic acid, ethylbenzene sulfonic acid, styrene sulfonic acid, naphthalene sulfonic acid, and combinations thereof. The phenol foam may exhibit appropriate crosslinking, curing, and foaming properties by including the curing agent.

[0053] The above curing agent may be included in an amount of 5 to 30 parts by weight, for example, 10 to 25 parts by weight, relative to 100 parts by weight of the above phenolic resin. The content of the above curing agent includes not only when a substance such as toluenesulfonic acid is used alone, but also when it is the content of a mixture prepared by mixing with a solvent such as an aqueous hydrochloric acid solution.

[0054] The foaming composition may include one surfactant selected from the group consisting of amphoteric, cationic, anionic, and nonionic surfactants and combinations thereof. For example, the thermosetting foam may include an ethylene oxide-based surfactant. The surfactant may be included in an amount of 1 to 8 parts by weight, for example, 2 to 6 parts by weight, per 100 parts by weight of phenolic resin.

[0055] The foaming composition may further include one additive selected from the group consisting of pentaerythritol, polyethylene glycol, monoethylene glycol, diethylene glycol, and combinations thereof. Specifically, the foaming composition may further include pentaerythritol, thereby making the molecular structure of the cell walls of the phenol foam more dense, which can control the diffusion of formaldehyde and improve thermal insulation. In addition, the compressive strength of the phenol foam can be further improved.

[0056] The phenol foam according to the present invention can exhibit superior physical and thermal properties compared to conventional phenol foams through compositional design that includes an optimal mixing ratio of phenol monomer and bisphenol A, an appropriate reaction ratio with respect to formaldehyde, and, if necessary, an addition of urea in an amount of 10 parts by weight or less per 100 parts by weight of phenolic resin.

[0057] The phenolic foam according to the present invention may have an independent cell ratio of 85% or more. For example, the phenolic foam may have an independent cell ratio of about 89% to about 99%. In the case of conventional phenolic foams, the formaldehyde content within the foam can be reduced by volatilizing formaldehyde with a low independent cell ratio. However, in this case, there is a problem in that the blowing agent also volatilizes, leading to increased thermal conductivity. The phenolic foam contains a sufficient blowing agent with a high independent cell ratio within the above range and has excellent initial thermal conductivity,

[0058] By applying a phenol monomer-bisphenol-formaldehyde resin that reduces residual formaldehyde, the amount of formaldehyde remaining in the foam is reduced, and at the same time, the density of the bubble cell walls is increased, thereby further reducing the release rate of formaldehyde.

[0059] In addition, the foam with a high closed-cell ratio as described above has a structure in which internal cells are separated from one another and surrounded by chemically stable cell walls, thereby blocking connection with the outside. This closed-cell structure blocks continuous passages between cells, thereby minimizing the path of gas movement and effectively reducing the external diffusion and release rate of volatile substances such as formaldehyde. That is, as the closed-cell ratio increases, the foam is predominantly composed of a closed structure, and the resistance to internal gas movement increases. Consequently, the paths for gas diffusion and formaldehyde release within the foam are restricted, resulting in a tendency for the surface release rate to decrease. Therefore, the phenolic foam of the present invention exhibits excellent preservation of the blowing agent due to the high closed-cell ratio, and as the density of the cell walls increases, it can simultaneously improve mechanical properties such as thermal insulation and compressive strength, as well as environmental stability, thereby demonstrating the characteristics of a high-performance phenolic foam.

[0060] The formaldehyde emission rate of the phenol foam according to the present invention, measured according to the KS M 1998 test method, is 0.06 mg / m³ 2 ·h or less, preferably 0.05 mg / m² 2 ·h or less, more preferably 0.04 mg / m² 2 ·h or less, more preferably 0.03 mg / m² 2 ·h or less, most preferably 0.02 mg / m² 2 By satisfying ·h or less, it exhibits significantly lower formaldehyde emission characteristics compared to existing commercial phenolic foams. This is because bisphenol A reacts with formaldehyde during the polymerization stage and is chemically consumed, thereby reducing the amount of fundamental residual formaldehyde in the resin, and a cured body with a stable structure is produced by forming rigid cell walls during the foaming reaction using this resin. This is of high technical significance in that it minimizes formaldehyde emissions compared to high-insulation phenolic foams with excellent initial and long-term thermal conductivity.

[0061] The phenolic foam according to the present invention may have a thermal conductivity of 0.022 W / m·K or less at an average temperature of 20°C as measured by a flat plate heat flow meter, and preferably 0.016 to 0.022 W / m·K. The above thermal conductivity is an initial thermal conductivity, which means that it exhibits excellent thermal insulation properties.

[0062] The phenolic foam according to the present invention may have a thermal conductivity of 0.024 W / m·K or less when measured at an average temperature of 20°C after being left in an environment of 110°C for 14 days, and preferably 0.017 to 0.024 W / m·K. The above thermal conductivity refers to long-term thermal conductivity. Maintaining the long-term thermal conductivity at 0.024 W / m·K or less means that the cell walls of the foam, which are the result of the polymerization and curing reactions, have a chemically structurally robust three-dimensional network structure.

[0063] In this way, the phenolic foam of the present invention can exhibit excellent performance as an insulating material by reducing the amount of formaldehyde released to the surface along with a high closed-cell ratio and exhibiting low thermal conductivity characteristics in both the early and long term.

[0064] In addition, the phenolic foam according to the present invention has a compressive strength of 100 kPa or more, for example 130 kPa or more, for example 140 kPa or more, for example 150 kPa or more as measured according to KS M ISO 844 standards, and has excellent structural stability against external loads. In particular, since there is almost no decrease in mechanical strength even in high temperature and high humidity environments, it is suitable for applications requiring long-term durability, such as building panels or refrigeration and freezing systems. On the other hand, since manufacturing a phenolic foam with excessively high compressive strength requires increasing the density of the foam or using separate additives, which may increase costs and make it difficult to secure thermal insulation, the compressive strength may be 300 kPa or less from this perspective.

[0065] According to another aspect of the present invention, the phenol foam can be manufactured through a process of foaming and curing a foaming composition comprising a phenolic resin, a foaming agent, and a curing agent.

[0066] According to one example, a method for manufacturing a phenolic foam according to the present invention may include (S1) a step of polymerizing a phenolic resin, (S2) a step of manufacturing a foaming composition, and (S3) a step of filling the foaming composition into a sheet material, but is not limited thereto, and a detailed description of each step is as follows.

[0067] (S1) Phenolic resin polymerization step

[0068] The phenolic resin used in the manufacturing method according to the present invention is a resin formed from a chemical reaction by adding bisphenol A and formaldehyde to a molten phenol monomer, wherein when the total weight of the phenol monomer and bisphenol A combined is 100% by weight, bisphenol A is included in an amount of 5 to 30% by weight, preferably 7 to 20% by weight.

[0069] When a phenolic resin is polymerized by mixing these phenol monomers and bisphenol A, the excessive generation of formaldehyde during the reaction is suppressed and chemical consumption is induced, thereby ensuring that no residual bisphenol A exists in the final foam and having the effect of reducing residual formaldehyde.

[0070] At this time, in order to polymerize the phenolic resin, an alkali catalyst is added at the start of polymerization to form pH conditions for the reaction of the phenolic resin. According to one example, it is preferable to add an alkali catalyst before raising the temperature of the reactor to set the pH to approximately 8 to 10, for example, pH 9, and then polymerize while maintaining the temperature of the reactor at 80 to 95°C. As the alkali catalyst, sodium hydroxide (NaOH), potassium hydroxide (KOH), barium hydroxide (Ba(OH)2), calcium hydroxide (Ca(OH)2), ammonia (NH4OH), etc., may be used, but are not limited thereto.

[0071] According to one example of the present invention, the step (S1) may be performed by including: (S1-1) a step of liquefying phenol by raising the temperature of the polymerization step of the phenolic resin to a temperature condition of 40 to 80°C; (S1-2) a step of liquefying a mixture of phenol and bisphenol by mixing bisphenol A with the liquefied phenol; (S1-3) a step of adding an aqueous formaldehyde solution to the liquefied mixture of phenol and bisphenol and polymerizing under a temperature condition of 80 to 100°C; and (S1-4) a step of terminating the polymerization.

[0072] The temperature condition of 40 to 80 ℃ in the above (S1-1) step is intended to ensure that the solid phase of phenol melts smoothly and that uniform reactivity is secured in subsequent mixing and polymerization reactions. At this temperature, stable liquefaction can be achieved without thermal decomposition or premature reaction, making it easy to control the process in subsequent steps.

[0073] The mixing of bisphenol A in step (S1-2) above is intended to improve the thermal properties and mechanical strength of the resin and to reduce the amount of formaldehyde leaching, and must be uniformly dispersed in the liquid phenol monomer to enable the formation of a consistent polymer structure in the subsequent polymerization reaction. During the mixing in step (S1-2), stirring conditions are maintained to ensure that bisphenol A is completely dissolved and dispersed, and viscosity control can be performed in the range of 50 to 80°C if necessary.

[0074] The temperature condition of 80 to 100°C in step (S1-3) above is desirable because it provides sufficient activation for the mixture of phenol monomer and bisphenol A to chemically react with formaldehyde, and it is a condition under which the polymerization of the resol-type or modified phenol resin proceeds stably. For example, step (S1-3) is carried out under stirring to ensure even contact between the aqueous and organic phases, and the reaction time and pH can be adjusted to achieve the target viscosity and degree of polymerization.

[0075] The termination of the reaction in the above (S1-4) steps is carried out by catalyst neutralization, temperature reduction, or the addition of a reaction inhibitor, etc., to ensure the processability of the resin by preventing excessive polymerization or gelation. The phenolic resin obtained after the reaction is terminated can be recovered while maintaining the target viscosity and reactivity so that it can be stably used in the subsequent (S2) foaming composition manufacturing step. If necessary, a dehydration operation may be performed to ensure the target viscosity and reactivity. The above reactor may apply any method selected from reflux, distillation, and combinations thereof, and a dehydration operation may be performed through reduced pressure so that the moisture content and viscosity required for the finally manufactured phenolic resin meet the intended requirements.

[0076] According to one example of the present invention, urea may be further mixed during the polymerization of a phenolic resin, and urea may be further mixed in the (S1) phenolic resin polymerization step or the (S2) foaming composition manufacturing step described later. The content of urea may be 10 parts by weight or less per 100 parts by weight of the polymerized phenolic resin, for example, 8 parts by weight or less, for example, 6 parts by weight or less, and may be 1 part by weight or more to ensure the adsorption of formaldehyde.

[0077] According to one example, if urea is mixed in step (S1), urea may be mixed in step (S1-1) or prior to step (S1-2) or (S1-3) or (S1-4).

[0078] (S2) Step for manufacturing a foamed composition

[0079] Next, a foaming composition preparation step (S2) is performed, in which a foaming agent, a surfactant, a curing agent, and an optional additive are added to the product of step (S1) to impart a foaming function, and the foaming composition is prepared by uniformly stirring sufficiently at room temperature.

[0080] According to one example of the present invention, the step of preparing a foaming composition may be carried out under temperature conditions of room temperature (15 to 25°C) or medium temperature (25 to 80°C), because there is a risk of premature foaming if the foaming composition is prepared at too high a temperature, and it is preferable to carry out the step under room temperature conditions to increase the viscosity of the phenolic resin and facilitate the mixing of additives.

[0081] According to one example of the present invention, as described above, urea may be mixed in step (S2).

[0082] (S3) Step of filling the above foamable composition into a cotton material and foaming it.

[0083] The mixed foamed composition obtained in step (S2) above is injected into a surface material (or release sheet or mold) selected from the group consisting of a metal layer, an organic and / or inorganic scrim layer, a polyolefin nonwoven layer, a polyolefin nonwoven layer including glass fiber, and combinations thereof, and then foamed. The bubbles generated during this process grow into a closed-cell structure, and the phenolic foam of the present invention may have an independent cell ratio of at least 85% of the total bubbles, preferably 89% to 99%.

[0084] (S4) Aging stage

[0085] According to one example of the present invention, the foamed phenolic resin obtained in step (S3) may be further subjected to an aging step (S4).

[0086] The above (S4) curing step may involve curing the foamed resin under conditions of approximately 50 to 80°C, or further inducing complete curing during this process. The curing step can stabilize residual reactions and induce stress relief within the resin, thereby increasing the stability of the foam.

[0087]

[0088] The method for manufacturing a phenol foam according to the present invention has the advantage of high process efficiency as it does not require an additional process to remove residual formaldehyde.

[0089]

[0090] According to another aspect of the present invention, an insulating material comprising the phenolic foam can be provided. The phenolic foam has significantly low residual formaldehyde of the phenolic resin used in its manufacture. In addition, the high density of the molecular structure constituting the cell walls of the foam made using the phenolic resin suppresses even minute residual formaldehyde from diffusing to the outside of the foam, thereby exhibiting eco-friendliness.

[0091] In addition, the above-mentioned phenolic foam can simultaneously exhibit excellent physical properties such as a high closed-cell ratio, excellent thermal insulation, and compressive strength. Accordingly, the above-mentioned phenolic foam can be applied for use as a building insulation material.

[0092] In addition, the phenol foam according to the present invention uses bisphenol A, but the leached bisphenol A is not detected during the bisphenol A leaching test, thereby ensuring safety for the human body and the environment.

[0093]

[0094] The above insulation material may further include a face material on one or both sides of the phenolic foam. For example, the face material of the phenolic foam may be selected from the group consisting of a metal layer, an organic and / or inorganic scrim layer, a polyolefin nonwoven layer, a polyolefin nonwoven layer including glass fiber, and combinations thereof. For example, the phenolic foam may include aluminum as the face material to impart flame retardancy.

[0095]

[0096] The present invention will be explained in more detail below through examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

[0097]

[0098] <Example>

[0099] Example 1

[0100] In a stirred reactor, 5.2632 parts by weight of bisphenol (BPA), 163.86 parts by weight of a 37% aqueous formaldehyde solution, and a 50% by weight aqueous sodium hydroxide solution were added relative to 100 parts by weight of phenol until the pH of the reaction solution reached 9. Then, the reaction was carried out for 3 hours while maintaining the temperature of the reactor at approximately 90°C to polymerize the phenolic resin.

[0101] After the reaction was completed, the reactor was cooled and urea was added to the phenolic resin prepared above. After the temperature of the reactor reached 50°C, an aqueous solution of p-toluenesulfonic acid was added until the pH became 7 to prepare a mixture containing the phenolic resin and urea.

[0102] Then, through reduced pressure, a finally manufactured urea-containing phenolic resin (referred to as "finally manufactured phenolic resin") was obtained, satisfying a final moisture content of 15% and a viscosity of 20,000 cps at 25°C. At this time, the urea was included in an amount of 6 parts by weight relative to 100 parts by weight of the finally manufactured phenolic resin (phenolic resin of Comparative Example 2 above).

[0103] Then, 106 parts by weight of the final manufactured phenolic resin, 4 parts by weight of an ethylene oxide-based surfactant, 10 parts by weight of a foaming agent mixture of cyclopentane:isopropyl chloride (1:1), and 23 parts by weight of a curing agent mixture of toluenesulfonic acid:DEG (8:2) were supplied to a stirrer and stirred to produce a foaming composition.

[0104] The above-mentioned stirred foam composition is fed into a caterpillar (temperature: 70℃) having spunbond nonwoven fabric, which is a surface material containing a polyolefin-based nonwoven fabric, placed at the top and bottom, to obtain a density of 34 kg / m³ 3A phenol foam product (thickness: 60 mm) was manufactured. The manufactured product was aged in an oven at 80°C for 10 hours.

[0105] Example 2

[0106] A phenol foam was prepared in the same manner as in Example 1, except that the added BPA was 8.1081 parts by weight.

[0107] Example 3

[0108] A phenol foam was prepared in the same manner as in Example 1, except that the added BPA was 11.1111 parts by weight.

[0109] Example 4

[0110] A phenol foam was prepared in the same manner as in Example 1, except that the added BPA was 25.0000 parts by weight.

[0111] Example 5

[0112] A phenol foam was prepared in the same manner as in Example 1, except that the added BPA was 42.8571 parts by weight.

[0113] Comparative Example 1

[0114] A phenol foam was prepared in the same manner as in Example 1, except that no BPA was added.

[0115] Comparative Example 2

[0116] In a stirred reactor, 163.86 parts by weight of a 37% formaldehyde aqueous solution and a 50% by weight sodium hydroxide aqueous solution were added relative to 100 parts by weight of phenol until the pH of the reaction solution reached 9. Then, the reaction was carried out for 3 hours while maintaining the temperature of the reactor at approximately 90°C to polymerize the phenolic resin.

[0117] After the reaction was completed, the reactor was cooled until the temperature of the reactor reached 50℃, and then an aqueous solution of p-toluenesulfonic acid was added until the pH reached 7 to prepare a phenolic resin.

[0118] And through reduced pressure, a finally manufactured phenolic resin was obtained, satisfying a final moisture content of 15% and a viscosity of 20,000 cps at 25°C.

[0119] Then, for every 100 parts by weight of the final manufactured phenolic resin, 4 parts by weight of an ethylene oxide-based surfactant, 10 parts by weight of a foaming agent mixture of cyclopentane:isopropyl chloride (1:1), and 23 parts by weight of a curing agent mixture of toluenesulfonic acid:DEG (8:2) were supplied to a stirrer and stirred to produce a foaming composition.

[0120] The above-mentioned stirred foam composition is fed into a caterpillar (temperature 70°C) having surface materials including polyolefin-based nonwoven fabric placed at the top and bottom, with a density of 34 kg / m³ 3 A phenol foam product (thickness: 60 mm) was manufactured. The manufactured product was aged in an oven at 80°C for 10 hours.

[0121] Comparative Example 3

[0122] A phenol foam was prepared in the same manner as in Example 1, except that the added BPA was 66.6667 parts by weight.

[0123] Comparative Example 4

[0124] A phenol foam was prepared in the same manner as in Example 1, except that the amount of BPA added was 100.0000 parts by weight, but it was impossible to prepare the foam because the BPA did not dissolve.

[0125] Comparative Example 5

[0126] A phenolic foam was prepared in the same manner as in Comparative Example 1, except that the added urea was 10 parts by weight per 100 parts by weight of the phenolic resin mentioned in Comparative Example 1.

[0127]

[0128] <Experimental Example>

[0129] Experiments were conducted on the phenol foams prepared in Examples 1 to 5 and Comparative Examples 1 to 3 and 5 as follows.

[0130] Experimental Example 1: Measurement of formaldehyde emission amount according to the small chamber method

[0131] Pretreatment was performed by removing the surface including the surface material so that 3 to 5 mm of the initial sample thickness could be removed based on the side facing indoors (the side that is not bonded to the wall during construction) among the two wide surfaces of the phenol foam products manufactured in each of the examples and comparative examples. Then, the amount of formaldehyde emitted from the surface of the phenol foam of the examples and comparative examples was measured according to KS M 1998, and the results are listed in Table 1 below.

[0132] Experimental Example 2: Measurement of Independent Bubble Rate (%)

[0133] Specimens were prepared by cutting the phenolic foams prepared in each of the examples and comparative examples into 2.5 cm (L) x 2.5 cm (W) x 2.5 cm (T) pieces. Then, following the ASTM D6226 measurement method, the closed cell content (Raw value (uncorrected)) of the specimens was measured using a closed cell content measuring instrument (Quantachrome, ULTRAPYC 1200e). The results are listed in Table 1 below.

[0134] Experimental Example 3: Measurement of Initial Thermal Conductivity (W / m·K)

[0135] Phenolic foams prepared in each of the examples and comparative examples were cut into specimens measuring 300 mm (L) × 300 mm (W), and the specimens were pretreated by drying them at 70°C for 12 hours. After pretreatment, the surface material was removed by hand, and the sample was cut to a thickness of 50 mm from the surface material. For samples where the surface material was difficult to remove by hand, the surface material was removed by cutting into thin slices, and then the sample was cut to a thickness of 50 mm. Then, the thermal conductivity was measured using the thermal conductivity measuring instrument 'HC-074-300 (EKO)' by applying the plate heat flow meter method and setting the measurement conditions to 10°C for the top plate and 30°C for the bottom plate, at an average temperature of 20°C, and the results are listed in Table 1 below.

[0136] Experimental Example 4: Measurement of Long-term Thermal Conductivity (W / m·K)

[0137] Phenolic foams prepared in each of the examples and comparative examples were cut into specimens with dimensions of 300 mm (L) × 300 mm (W). The specimens were dried at 110°C for 14 days and then pretreated by being left under constant temperature and humidity conditions of 23±3°C and 50±10% for 3 hours. Then, the thickness of the pretreated specimens was reduced by removing the surface material as in the initial thermal conductivity measurement method. The plate heat flow meter method was applied to the specimens, and the measurement conditions were set to 10°C for the top plate and 30°C for the bottom plate. The thermal conductivity was measured using the thermal conductivity measuring equipment 'HC-074-300 (EKO)' at an average temperature of 20°C, and the results are listed in Table 1 below.

[0138] Experimental Example 5: Measurement of Compressive Strength (kPa)

[0139] The phenolic foam of the examples and comparative examples was prepared as specimens with a thickness of 100 mm (L) × 100 mm (W). The specimens were placed between the wide plates of a Lloyd Instruments LF Plus Universal Testing Machine (UTM). The UTM was set to a speed of 10% of the specimen thickness in mm / min, and a compressive strength test was started. Pressure was applied for 1 minute until 10% of the specimen thickness was compressed, and the maximum strength was recorded. The compressive strength was measured according to the KS M ISO 844 standard, and the results are listed in Table 1 below.

[0140] Experimental Example 6: Pyrolysis Analysis Test

[0141] 1) Analysis Method

[0142] : 0.5 mg of the phenol foam of the examples and comparative examples was collected (from the center in the thickness direction and from a portion more than 100 mm inward from the side) and pyrolyzed using a gas chromatography-mass spectrometer (GCMS, Agilent, 8890-5977C) equipped with a pyrolyzer pretreatment device (Pyrolyzer, Frontier, EGA / PY-3030D), after which the generated pyrolyzates were separated and analyzed. The specific conditions are as follows.

[0143] - The pyrolysis conditions are a single-shot injection at 600°C for 10 minutes.

[0144] - For the GCMS conditions, a GC / MS system equipped with a UA-5 (30 mm × 0.25 mm id, 0.25 μm film) column was used, and He (1.0 mL / min) was used as the carrier gas.

[0145] - The split ratio was set to 50:1, and the injection port temperature was set to 320℃.

[0146] - The oven temperature program was executed as follows: 40℃ (2 min) → 20℃ / min → 310℃ (14 min).

[0147] - MS was acquired in EI mode (70 eV), and the scan range was set to m / z 40-500.

[0148] 2) Data Interpretation

[0149] Pyrolysis analysis was performed on the foams of Comparative Examples 1, 2, and 5 prepared with bisphenol A, and on the foams of Examples 1 to 5 and Comparative Examples 3 and 4 prepared with bisphenol A. The total ion chromatogram (TIC) of the phenol foam insulation is shown in Fig. 1, and to distinguish the phenol foam with added BPA, the extractive ion chromatogram (EIC) was analyzed based on a specific ion fragment (m / z = 164) (Fig. 2). As a result, the amount of pyrolysis products detected at a retention time of 10.22 min showed a tendency to increase as the BPA content increased. As shown in Fig. 2, the corresponding pyrolysis product compounds had characteristic ion fragments of m / z = 164 and m / z = 149, exhibiting a different pattern from the fragmentation pattern of the BPA monomer itself (Fig. 3). On the other hand, since this thermal decomposition product was not detected in phenol foam without BPA added, the compound was presumed to have originated from BPA and was determined to be a BPA-derived peak.

[0150] The results of the thermal decomposition analysis (mass spectrum) of the foams of Examples 1 to 5 and Comparative Examples 1 to 3 and 5 were used to determine whether a peak of BPA monomer was detected and whether a peak of BPA origin was detected. If detected, it was indicated as “O”, and if not detected, it was indicated as “X”, as shown in Table 1 below.

[0151] In addition, an Extracted Ion Chromatogram (EIC) was extracted for the phenol (m / z = 94) generated during the thermal decomposition of the phenol foams of Comparative Example 1, Comparative Example 2, Comparative Example 5, Example 1, and Example 5, and the area of ​​the corresponding phenol peak was measured. Subsequently, using the measured phenol peak area values ​​and the peak area values ​​of the BPA-derived components, the ratio “R” representing the relative contribution of the two components was calculated as follows and is shown in Table 2.

[0152] R = (Integrated area of ​​BPA-derived peak) / (Integrated area of ​​phenol peak) × 10 4

[0153] Experimental Example 7: Elution amount test of phenolic foam (HPLC-DAD)

[0154] The phenol foams of the Examples and Comparative Examples were crushed to prepare 250 mg of specimens. 15 mL of acetonitrile (ACN) was added to the specimens and stirred at room temperature for 72 hours. After stirring was complete, the solution was allowed to stand for 1 hour, and the supernatant was filtered through a 0.45 μm syringe filter. The filtrate was mixed with a 10 mM ammonium acetate solution at a ratio of 6:4 (v / v) and analyzed using HPLC-DAD (High Performance Liquid Chromatography-Diode Array Detector), with the HPLC analysis conditions as follows.

[0155] - Equipment: HPLC (Agilent 1200 series)

[0156] - Mobile phase

[0157] A: 10mM Ammonium acetate (aqueous)

[0158] B: Acetonitrile (HPLC-grade)

[0159]

[0160] - Gradient program (A:B)

[0161] - Flow rate: 1.0 mL / min

[0162] - Column: ZORBAX Eclipse XDB-C18, 4.6 × 250 mm, 5 μm

[0163] - Column temperature: 30 ℃

[0164] - Injection volume: 10 μL

[0165] - Detector: Diode-array detector (DAD), 276 nm

[0166] Bisphenol A (BPA) was analyzed using High Performance Liquid Chromatography (HPLC) under the same conditions, and the retention time was found to be approximately 11.4 minutes. When the foam extracts of the subject examples and comparative examples were analyzed under the same conditions, the presence or absence of a significant peak at the time point corresponding to the retention time of BPA (=11.4 minutes) was checked, and if not detected, it was marked as “X”, and if detected, it was marked as “O”, as shown in Table 2 below.

[0167] Experimental Example 8: Test of Leaching Amount of Phenolic Foam (Korea Institute of Construction & Living Environment Testing)

[0168] The Korea Institute of Construction & Living Environment Testing was commissioned to test the leaching amounts of phenol, formaldehyde, and bisphenol A from the phenol foam of Example 3. The leaching amounts were tested according to the '2-35 Bisphenol A (including phenol and p-tertiarybutylphenol)' test method in the Food Utensils and Containers and Packaging Codex notified by the Ministry of Food and Drug Safety. A copy of the test results is attached in Fig. 4.

[0169]

[0170]

[0171] The results of various physical property tests performed on the phenol foams of the examples and comparative examples according to the present invention are shown in Tables 1 and 2. First, when comparing the formaldehyde emission characteristics, the emission amount of Comparative Example 1, which did not contain BPA, was 0.084 mg / m²·h, and Comparative Example 2, which did not contain BPA and urea under the same conditions, showed a relatively high formaldehyde emission amount of 0.511 mg / m²·h. On the other hand, Examples 1 to 4 of the present invention, which contained BPA in the range of 5 to 25 weight%, showed significantly lower formaldehyde emission amounts of 0.056 to 0.012 mg / m²·h, and in particular, Example 4 showed the most excellent reduction effect at 0.012 mg / m²·h. This is because BPA reduces the amount of unreacted formaldehyde present during the polymerization process with phenol and formaldehyde, and as a result, the diffusion and release of formaldehyde inside the bubbles or in the final foam during the foaming process can be seen as being fundamentally suppressed. In addition, Example 5, which had an excess amount of BPA added, also showed a very low formaldehyde release amount (0.005 mg / m²·h), but an adverse effect was observed in which the foam structure became unstable due to the excessive BPA content.

[0172] As a result of analyzing the closed-cell ratio to confirm the correlation with the cell structure, Examples 1 to 4 exhibited a high closed-cell structure in the range of 88.6% to 90.9%, which can be seen as an improvement compared to Comparative Examples 1, 2, or 5. Since BPA forms a robust cell structure through a chemical reaction with formaldehyde, it can be interpreted that it helps form a stable closed-cell structure throughout the foam. Such an increase in the closed-cell ratio has the effect of further reducing the formaldehyde release rate within the foam by minimizing the gas migration path. On the other hand, in the case of Comparative Example 3, in which 40% by weight or more of BPA was added, the closed-cell ratio was significantly lower.

[0173] The thermal conductivity measurement results also confirm that the appropriate amount of BPA added contributes to the stabilization of the foam structure. Examples 1 to 4 maintained excellent thermal insulation performance, with both the initial and long-term thermal conductivity being low. On the other hand, Comparative Example 3, which had an excessive amount of BPA added, showed a higher thermal conductivity due to the instability of the foam structure.

[0174] In addition, Examples 1 to 4, which contained BPA within an appropriate range, exhibited higher compressive strength compared to the Comparative Example, which can be attributed to BPA contributing to increased cell wall density within the polymerization network. However, when BPA was added in excess, the compressive strength decreased to 134 kPa due to bubble collapse and non-uniformity (Comparative Example 3), or it was confirmed that the phenolic foam itself was not formed because it did not dissolve in the phenolic resin (Comparative Example 4).

[0175] In the thermal decomposition analysis results of the examples (Table 2), no peak corresponding to the BPA monomer itself was detected, which means that BPA reacted completely during the polymerization process and did not remain in the final foam. However, in the compositions containing BPA, a 'BPA-derived peak' containing a characteristic fragment (m / z = 164) generated during the thermal decomposition of the BPA reactant was detected, and its area increased proportionally with increasing BPA content; this was intended to confirm whether BPA was used in the finally manufactured phenol foam. Additionally, through the relative ratio of the phenol peak to the BPA-derived peak (R value), it was confirmed that the R value increased as the BPA content increased, while all comparative examples without BPA showed R=0.

[0176] Finally, in the BPA leaching test using HPLC-DAD, no BPA was detected in any of the examples, despite the use of BPA. This implies that BPA does not exist in a free state within the final foam but is completely immobilized within the polymer structure and does not leach out. These results strongly support the fact that the composition of the present invention simultaneously ensures safety regarding BPA leaching as well as formaldehyde reduction.

[0177] Consequently, a comprehensive analysis of Tables 1 and 2 shows that when BPA is used within an appropriate range, it can significantly improve environmental performance through the chemical consumption of formaldehyde, while simultaneously enhancing mechanical strength, closed-cell ratio, and thermal insulation. Therefore, it was experimentally confirmed that the BPA content conditions presented in this invention represent the optimal compositional range for simultaneously securing formaldehyde reduction, foam structural stability, and mechanical and thermal performance.

[0178]

[0179] Although an embodiment of the present invention has been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the present invention as described in the claims, and such modifications and changes are also to be included within the scope of the rights of the present invention.

Claims

1. A cured product of a foamable composition comprising a phenolic resin, a foaming agent, and a curing agent, and The above phenolic resin comprises a polymer of a mixture of a phenol monomer, bisphenol A, and formaldehyde, Phenolic foam.

2. In Paragraph 1, When the combined weight of the above phenol monomer and bisphenol A is 100% by weight, the bisphenol A is mixed in an amount of 5 to 30% by weight. Phenolic foam.

3. In Paragraph 1, The initial thermal conductivity measured by the plate heat flow meter method at an average temperature of 20 ℃ is 0.022 W / m·K or less, Phenolic foam.

4. In Paragraph 1, The long-term thermal conductivity measured by the plate heat flow meter method at an average temperature of 20℃ after being left in a 110℃ environment for 14 days is 0.024 W / m·K or less, Phenolic foam.

5. In Paragraph 1, A closed-cell ratio of 85% or more as measured according to ASTM D6226, Phenolic foam.

6. In Paragraph 1, Satisfying that the reaction molar ratio (f / p value) of formaldehyde to the above phenol monomer is greater than 1 and less than 2.5, Phenolic foam.

7. In Paragraph 1, The above foaming composition further comprises urea, Phenolic foam.

8. In Paragraph 7, Urea is included in an amount of 10 parts by weight or less per 100 parts by weight of the above phenolic resin, Phenolic foam.

9. In Paragraph 1, 100 kPa or more with a compressive strength measured by the KS M ISO 844 measurement method, Phenolic foam.

10. In Paragraph 1, Bisphenol A-free, Phenolic foam.

11. A method for manufacturing a phenol foam according to any one of claims 1 to 10, (S1) Phenolic resin polymerization step; (S2) Step for preparing a foamed composition; and (S3) A step of filling the foamed composition into a cotton material; comprising, Method for manufacturing phenol foam.

12. In Paragraph 11, The above (S1) step is, (S1-1) The polymerization step of the phenolic resin is a step of liquefying the phenol by raising the temperature to 40~80℃; (S1-2) A step of mixing bisphenol A with liquefied phenol to liquefy a mixture of phenol and bisphenol; (S1-3) a step of adding an aqueous formaldehyde solution to the liquefied mixture of the above phenol and bisphenol and polymerizing under a temperature condition of 80 to 100 ℃; and (S1-4) Steps for terminating polymerization; performed sequentially, Method for manufacturing phenol foam.

13. In Paragraph 11, Further mixing of urea in step (S1) or (S2) above, Method for manufacturing phenol foam.

14. In Paragraph 11, (S4) Including an additional aging step, Method for manufacturing phenol foam.

15. An insulating material comprising a phenol foam according to any one of claims 1 to 10.

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