KR20220063492A - Phenol foam and method of producing the same - Google Patents

Abstract

Provided is a phenol foam which comprises a foaming agent including a first foaming agent and a second foaming agent, wherein the first foaming agent is a cyclic alkane having 6 or less carbon atoms, the second foaming agent is a linear or branched chlorinated aliphatic alkane having 3 to 6 carbon atoms, the second foaming agent is included more than the first foaming agent, and a boiling point difference between the first foaming agent and the second foaming agent is 10 to 20 ℃.

Description

Phenolic foam and its manufacturing method

The present invention relates to a phenolic foam and a method for preparing the same.

Foam is an essential material used to prevent energy loss in buildings. As the importance of green growth continues to be emphasized worldwide due to global warming, insulation is becoming more important to minimize energy loss.

Conventionally, as a foaming agent used for a foam, chlorofluorocarbon (CFC) having a low thermal conductivity and excellent thermal insulation has been used. However, the use of CFCs was abolished by the Montreal Protocol adopted in 1987 because they greatly contribute to the destruction of the ozone layer and climate change. As a result, although the conversion to hydrofluorocarbon (HFC), etc., which has a relatively low ozone depletion coefficient as a blowing agent, has progressed, it still has a high global warming coefficient, so there is still a problem. Accordingly, there is a need for a foaming agent that has a low ozone depletion coefficient and a low global warming coefficient, has a low thermal conductivity like CFCs and HFCs, and can impart excellent physical properties at the same time.

An object of the present invention is to provide a phenolic foam that has a low ozone depletion coefficient and a low global warming coefficient, including a hydrocarbon-based foam system, has an appropriate average diameter uniformly, exhibits excellent thermal insulation properties, and at the same time has excellent physical properties. will be.

It is also an object of the present invention to provide a method for producing the phenolic foam. The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned will be understood by the following description. and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the appended claims.

A foaming agent comprising a first foaming agent and a second foaming agent according to the present invention is included, wherein the first foaming agent is a cyclic alkane having 6 or less carbon atoms, and the second foaming agent is a linear or branched foaming agent having 3 to 6 carbon atoms. It is possible to provide a phenolic foam that is a chlorinated aliphatic alkane, contains more of the second blowing agent than the first blowing agent, and has a boiling point difference between the first blowing agent and the second blowing agent of 10°C to 20°C.

In addition, preparing a foaming composition comprising a phenolic resin, a foaming agent, a surfactant and a curing agent according to the present invention, and stirring the foaming composition; and discharging, foaming and curing the stirred foam composition; wherein the foaming agent includes a first foaming agent and a second foaming agent, and the first foaming agent is a cyclic alkane having 6 or less carbon atoms, and the first foaming agent is a cyclic alkane having 6 or less carbon atoms. 2 The blowing agent is a linear or branched chlorinated aliphatic alkane having 3 to 6 carbon atoms, contains more of the second blowing agent than the first blowing agent, and the boiling point difference between the first blowing agent and the second blowing agent is 10 ° C. to It is possible to provide a method for producing a phenolic foam at 20 °C.

The phenolic foam according to the present invention has a low ozone depletion coefficient and also contains a hydrocarbon-based foaming agent with a low global warming coefficient, and uniformly has cells of an appropriate size, low water absorption, excellent compressive strength, dimensional stability, improved thermal conductivity, etc. It is to provide a phenolic foam having.

In addition, the method for producing a phenol foam according to the present invention can prepare the phenol foam.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 is a schematic diagram briefly showing a method for measuring the dimensional stability of the phenolic foam of the present invention.
Figure 2 is a schematic diagram briefly showing a method for measuring the water absorption rate of the phenol foam of the present invention.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Hereinafter, the phenolic foam according to some embodiments of the present invention will be described.

An embodiment of the present invention includes a foaming agent including a first foaming agent and a second foaming agent, wherein the first foaming agent is a cyclic alkane having 6 or less carbon atoms, and the second foaming agent is a linear or carbon number 3 to 6 foaming agent. Provided is a phenolic foam that is a branched chlorinated aliphatic alkane, contains more of the second blowing agent than the first blowing agent, and has a boiling point difference between the first blowing agent and the second blowing agent of 10°C to 20°C.

Conventionally, chlorofluorocarbon (CFC) having a low thermal conductivity has been used as a foaming agent, but the use of CFC has been abolished due to the depletion of the ozone layer. As a result, although hydrofluorocarbon (HFC), which has a relatively low ozone depletion coefficient, has been used as a blowing agent, there is still a problem because it has a high global warming coefficient. Among the blowing agents, hydrocarbon-based blowing agents have a low ozone depletion coefficient and low global warming coefficient, which is preferable from an environmental point of view, but in general, hydrocarbon-based blowing agents do not sufficiently lower thermal conductivity, control cell size is not easy, excellent moisture absorption rate, compression There is a limit to providing a foam having the physical properties of strength and dimensional stability at the same time.

The phenol foam contains a hydrocarbon-based foaming agent, has a low ozone depletion coefficient, a low global warming coefficient, and uniformly has cells of an appropriate size, low moisture absorption, excellent compressive strength, dimensional stability and improved thermal conductivity at the same time can indicate

The phenolic foam may include a hydrocarbon-based blowing agent as a blowing agent, thereby lowering the global warming coefficient along with the ozone depletion coefficient. In the case of using a conventional hydrocarbon, for example, normal butane, etc. as the blowing agent, there may be problems such as not providing sufficient thermal insulation properties. In addition, when a separate additive, for example, a siloxane compound, etc. is added in order to simultaneously have more than a certain amount of physical properties while including a conventional hydrocarbon, the viscosity increases, so a separate process in consideration of the increase in viscosity may be required. there is. Accordingly, production efficiency may be reduced, and the cost may be increased due to additives, which may be uneconomical.

The phenol foam includes a first foaming agent that is a cyclic alkane having 6 or less carbon atoms as a foaming agent, and a second foaming agent that is a linear or branched chlorinated aliphatic alkane having 3 to 6 carbon atoms. It can impart bubbles, low water absorption, excellent compressive strength, dimensional stability, and improved thermal conductivity.

The foaming agent contains more of the second foaming agent than the first foaming agent, and exhibits uniform cells of appropriate size, low moisture absorption, excellent compressive strength and dimensional stability, and not only thermal conductivity at initial room temperature, but also long-term thermal conductivity can improve For example, when the first foaming agent contains more than the second foaming agent, it becomes difficult to control the balance of foaming and curing as the temperature required for foaming increases, so that the cell diameter becomes large, non-uniform, and voids are easily generated. This may increase moisture absorption. In addition, the first foaming agent is likely to be liquefied at room temperature, thereby lowering the foaming pressure, reducing thermal conductivity, and causing shrinkage of the foam.

The difference in boiling points of the first foaming agent and the second foaming agent (= |boiling point of the first foaming agent - boiling point of the second foaming agent|) is about 10°C to about 20°C. Accordingly, the foaming agent with a low boiling point can function similarly to the nucleating agent while foaming first, and the balance with the curing reaction can be controlled by appropriately controlling the speed and distribution of foaming of the foaming agent with a high boiling point. For example, if the difference between the boiling points of the first foaming agent and the second foaming agent is less than the above range, the foaming reaction may occur at once, and the foam may not be sufficiently advanced in the thickness direction of the foam and cured without sufficiently forming the foam. And, when the boiling point difference exceeds the above range, the low boiling point foaming agent volatilizes, so that efficient bubble collection is not achieved, the cell diameter becomes non-uniform due to the non-uniform foaming reaction, and thermal conductivity and compressive strength may be lowered. . The boiling point or the like means a boiling point at atmospheric pressure (1 atm).

The foaming agent including the first foaming agent and the second foaming agent may have an average boiling point value of about 38 °C to about 43 °C. Accordingly, the phenolic foam has cells of an appropriate size uniformly, has low water absorption, excellent compressive strength, and dimensional stability, and improves thermal conductivity at room temperature in the initial stage, and can maintain long-term thermal conductivity above a certain level. For example, when the average boiling point of the foaming agent exceeds the above range, large-diameter cells are non-uniformly distributed due to the imbalance between foaming and curing reaction, moisture absorption is increased, foaming pressure is lowered, thermal conductivity is lowered, and , compressive strength and dimensional stability may be deteriorated. In addition, when the temperature of the conveyor belt is increased for smooth foaming, the reactivity of the foaming composition may be excessively increased, and accordingly, the bubbles may become more non-uniform, and physical properties may be significantly reduced. And, when the average boiling point of the foaming agent is less than the above range, the foaming rate is excessively fast, the cells are easily destroyed, the foaming agent is easily volatilized to lower the thermal conductivity, and physical properties such as dimensional stability and compressive strength may be reduced, and voids may occur. The area of is increased, so that the water absorption rate can be increased.

The phenolic foam may include the first blowing agent to the second blowing agent in a weight ratio of about 2:8 to about 4.5:5.5. For example, it may be included in a weight ratio of about 2: 8 to about 4:6 or about 3: 7 to about 4:6. When the content of the second foaming agent is less than the above range, it becomes difficult to control the balance of foaming and curing as the temperature required for foaming increases, so that the cell diameter becomes large, non-uniform, and voids are generated, thereby increasing water absorption. In addition, a relatively large number of the first blowing agent having a high boiling point may decrease the foaming pressure and decrease dimensional stability, and the first blowing agent may be liquefied at room temperature to reduce thermal conductivity. In addition, when the temperature of the conveyor belt is increased for smooth foaming, the reactivity of the foaming composition is excessively increased, the cell diameter is increased, the uniformity is deteriorated, and the initial thermal insulation property may be deteriorated. And, when the content of the second foaming agent exceeds the above range, the foaming rate is excessively increased, the cells are easily destroyed, the foaming agent is easily volatilized to lower the thermal conductivity, and physical properties such as dimensional stability and compressive strength may be reduced. In addition, the area of the void may be increased to increase the moisture absorption rate.

The first blowing agent may include one selected from the group consisting of cyclobutane, cyclopentane, cyclohexane, and combinations thereof. And, the second blowing agent may include one selected from the group consisting of propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride, chlorohexane, and combinations thereof. For example, the first foaming agent may be a foaming agent having the highest boiling point in the phenolic foam, and the second foaming agent may be a foaming agent having the lowest boiling point in the phenolic foam.

The blowing agent may be included in an amount of about 3 parts by weight to about 17 parts by weight based on 100 parts by weight of the phenol foam. By being included in the content of the above range, the foaming agent can provide excellent dimensional stability, compressive strength, and uniform cell diameter along with low thermal conductivity at the same time. For example, when the content of the foaming agent exceeds the above range, the foaming cells are destroyed to deteriorate the thermal insulation properties, the dimensional change rate of the foam may increase, and the compressive strength may be reduced.

The blowing agent may not include hydrofluoroolefin (HFO). Hydrofluoroolefin (HFO) can easily lower thermal conductivity compared to hydrocarbon-based foaming agents, thereby making it easier to secure thermal insulation. On the other hand, hydrofluoroolefin (HFO) exhibits high polarity, plasticizes a phenol resin having a hydroxyl group (-OH), which is a hydrophilic group, lowers the viscosity, increases the cell diameter variation, and tends to lower the physical properties, A separate process is required to control the balance of foaming and curing. The phenolic foam does not contain hydrofluoroolefin (HFO), has cells of an appropriate size, and at the same time has low moisture absorption, excellent compressive strength and dimensional stability, and improved thermal conductivity.

The phenolic foam may have an average cell diameter of about 80 μm to about 130 μm in a cross section bisecting the thickness direction of the foam. For example, it may be about 80 μm to about 120 μm. The average cell diameter refers to the average value of the cell diameter in a section (parallel to the surface to which the face member is attached) bisected in the thickness direction perpendicular to the surface to which the face material is attached, so as to include the most central portion of the phenolic foam. do. For example, when the average cell diameter of the phenolic foam is less than the above range, the foam is too dense and heavy, and thus structural stability is deteriorated, such as easily falling off in the event of a fire, etc., and the cell wall thickness is thin to maintain low thermal conductivity for a long time and there may be a problem of lowering brittleness. And, when it exceeds the above range, the conductive properties through the cell wall increase and the thermal insulation performance is deteriorated, the cell membrane per unit thickness of the foam is reduced, the closed cell ratio is lowered, and the compressive strength can be lowered.

In addition, the phenolic foam having an average cell diameter in the above range may have a standard deviation of the cell diameter in the cross section bisecting the thickness direction of 10% to 25%. For example, the standard deviation of the cell diameter may be about 10% to about 20%. Since the cell diameter of the portion close to the center of the phenolic foam is larger than the cell diameter of the surface of the foam, the standard deviation of the cell diameter may be larger as the cell diameter is closer to the center than the surface. The phenolic foam can exhibit excellent compressive strength, thermal conductivity and physical properties such as dimensional stability and water absorption by having a standard deviation of the above range in the bisected cross section in the thickness direction of the foam located at the center. Specifically, when the standard deviation of the phenolic foam exceeds the above range, the compressive strength is lowered due to non-uniform air bubbles, and when an external force is applied, there is a problem that warpage is likely to occur, and dimensional stability is lowered.

The phenolic foam may have a compressive strength of 100 kPa to 300 kPa according to KS M ISO 844. For example, it may be about 140 kPa to about 300 kPa. Specifically, when the compressive strength is less than the above range, there may be a problem of poor handling properties because it is easy to break during construction and use. And, when it exceeds the above range, there may be a problem in that processing as a building insulation material becomes difficult.

In addition, the phenolic foam may have an average value of the dimensional change ratio of 0% to 1.0% according to the following formula (1).

[Equation 1]

Dimensional change rate (%)=[(Initial length (a)-Later length (a'))/Initial length (a)] X 100

In Equation 1, the initial length (a) is the length of each line of n equal points in the length (L) and width (W) directions of the phenolic foam, and the later length (a') is the phenolic foam It means the later length (a') of each line at each point after standing in an oven at 70° C. for 48 hours. In this case, n may be 2 to 5. n may be 3.

The phenol foam includes the first foaming agent and the second foaming agent, and by adjusting the boiling point difference of the first foaming agent and the second foaming agent, it may exhibit improved dimensional stability as described above with excellent thermal insulation properties. The average value of the dimensional change rate may be about 0% to about 0.9%.

In addition, the phenolic foam may have a thermal conductivity of about 0.018 W/m·K to about 0.023 W/m·K measured at an average temperature of 20° C. according to KS L 9016. For example, it may be from about 0.018 W/m·K to less than about 0.020 W/m·K. In general, when the first foaming agent is included, it is easy to liquefy at room temperature, and thus thermal conductivity may be lowered. On the other hand, the phenol foam includes the first foaming agent and the second foaming agent, and by controlling the difference in boiling points of the first foaming agent and the second foaming agent, it can exhibit excellent physical properties and improved thermal insulation at low temperature and room temperature.

And, according to EN13823, the thermosetting foam has a thermal conductivity of about 0.019 W/m·K to about 0.023 W/ It may be m·K. For example, it may be about 0.019 W/m·K to about 0.021 W/m·K. The thermal conductivity represents the long-term thermal insulation properties of the foam, and a typical hydrocarbon-based foaming agent has a high thermal conductivity, and the thermal conductivity tends to increase over time when used for a long period of time. The phenolic foam can maintain not only initial thermal insulation at room temperature, but also long-term thermal insulation at a certain level or more.

The phenol foam can prevent the formation of voids by controlling a foaming agent and the like. In contrast to the cell diameter, the foam may partially have large pores, which are referred to as voids. If the area of the void is too large, thermal insulation and compressive strength may be deteriorated. The degree of voiding of the foam can be measured by the water absorption rate as follows. The phenolic foam may have a low water absorption rate. The phenolic foam may have a water absorption rate of about 1% to about 4% according to Formula 1, measured according to KS M ISO 2896. For example, the moisture absorption rate may be about 1% to about 3%.

[Equation 1]

Specifically, the moisture absorption rate may be measured using an apparatus as shown in FIG. 2 . In Equation 1, WAv is the water absorption rate (%) of the foam, m1 is the initial weight of the foam 20 itself before immersion in water, m2 is the weight of the mesh 10 itself for containing the foam, m3 is The combined weight of the foam and the mesh in water after immersion in water for 96 hours, V ₀ is the volume of the foam before immersion in water, V1 is the volume of the foam after immersion in water for 96 hours, Vc is the volume of the bubble observed from the outside located on each side of the foam, and ρ is the density of water in which the foam is immersed.

In general, if foaming and curing are not properly balanced, the area of voids may increase. For example, when the foaming pressure is too high or the foaming ratio is too large, the bubbles may be broken, and voids may be formed while merging between the cells before forming the closed cells. The phenolic foam can prevent the formation of voids by properly controlling the balance of foaming and curing. Accordingly, by having a moisture absorption rate in the above range, excellent thermal insulation and durability can be implemented for a long period of time. Specifically, when the water absorption rate of the phenolic foam exceeds the above range, thermal conductivity, particularly long-term thermal conductivity may be lowered, compressive strength may be lowered, and there may be a problem of bending / shrinkage during construction.

The phenolic foam may have a closed cell ratio of about 75% to about 98%. Including a foaming agent having a high boiling point, when the reaction temperature is increased, the curing speed is also increased, and the foaming pressure is rapidly increased, and the cell diameter is increased. The phenolic foam may exhibit physical properties such as excellent thermal insulation, compressive strength, and excellent dimensional stability by maintaining the closed cell ratio within the above range.

Another embodiment of the present invention comprises the steps of preparing a foaming composition comprising a phenol-based resin, a foaming agent, a surfactant and a curing agent, and stirring the foaming composition; and discharging, foaming and curing the stirred foam composition; wherein the foaming agent includes a first foaming agent and a second foaming agent, and the first foaming agent is a cyclic alkane having 6 or less carbon atoms, and the first foaming agent is a cyclic alkane having 6 or less carbon atoms. 2 The blowing agent is a linear or branched chlorinated aliphatic hydrocarbon having 3 to 6 carbon atoms, contains more of the second blowing agent than the first blowing agent, and the boiling point difference between the first blowing agent and the second blowing agent is 10° C. to It provides a method for producing a phenolic foam at 20°C.

As described above by the manufacturing method, while lowering the ozone depletion coefficient and the global warming coefficient, the phenolic foam having uniformly sized cells, low water absorption, excellent compressive strength, dimensional stability, and improved thermal conductivity. can be manufactured. Matters related to the foaming agent and the phenol foam are the same as those described above, except for those specifically described below.

First, the method for producing the phenol foam includes preparing a foaming composition including a phenol-based resin, a foaming agent, a surfactant and a curing agent, and stirring the foaming composition.

For example, the manufacturing method of the phenol foam includes the steps of mixing the phenol-based resin, a foaming agent, and a surfactant, and after aging, adding a curing agent to prepare a foaming composition; and stirring the foaming composition in a mixer.

The phenol-based resin may be obtained by reacting phenol and formaldehyde, and may include, for example, a resol-based phenol resin (hereinafter, 'resol resin'). The phenolic resin may be included in the phenolic foam in an amount of about 30 wt% to about 90 wt%, or about 50 wt% to about 90 wt%, or about 55 wt% to about 90 wt%.

The moisture content contained in the phenol-based resin may be 9 wt% to 20 wt%. If the moisture content is less than the above range, there may be a problem that the foam is not formed properly because the reactivity control is not made in the foam manufacturing process. And, when it exceeds the above range, water vapor is contained in the bubble, and the pressure in the bubble becomes too high, and at the same time the formation of the bubble wall is disturbed by the water vapor, the bubble may be broken, and the closed cell rate and compressive strength are lowered. There may be a problem.

The phenolic resin may have a viscosity of 10,000 cps to 50,000 cps at 20° C., for example, about 10,000 cps to 30,000 cps. When the viscosity of the phenol-based resin exceeds the above range, there may be a problem in that the foam is not formed due to the stress of the resin.

And, the surfactant includes one surfactant selected from the group consisting of amphoteric, cationic, anionic, nonionic surfactants and combinations thereof. For example, nonionic surfactants such as polysiloxane, polyoxyethylene sorbitan fatty acid ester, ethylene oxide adduct of castor oil, and castor oil-based surfactant can be used.

The phenolic foam may include a nonionic surfactant of Hydrophile-Lipophile Balance (HLB) 11 to 18. The HLB, a concept proposed by William Griffin of Atlas Powder Company, is a numerical value indicating the degree of affinity for water and oil of a surfactant, and ranges from 0 to 20. big. The nonionic surfactant may have a different HLB value depending on the molecular structure of the hydrophobic portion and the length and distribution of the repeating structure of the hydrophilic portion. For example, the surfactant may be a castor oil-based surfactant of HLB 13 to 17. The phenolic foam may include the surfactant to increase the rate of forming a stable interface between the phenolic resin, the foaming agent, and the curing agent. In addition, it is possible to stabilize the interface during the growth of the foam cell. Accordingly, it is possible to uniformly have cells of an appropriate size in the foam, and to simultaneously impart low water absorption, excellent compressive strength, dimensional stability, and improved thermal conductivity. Specifically, when the HLB is less than the above range, there is a problem in that the interface is not stabilized, so that the bubble cells do not burst or grow uniformly. In addition, when the HLB exceeds the above range, there may be a problem in that it is difficult to apply in the process because it exists as a high viscosity or solid at room temperature, and the hydrophilicity is rapidly increased so that the hydrophobic foaming agent cannot be dispersed in the phenolic resin.

The blowing agent: the surfactant may be included in a weight ratio of about 1: 0.3 to about 1: 0.6. The phenolic foam lowers the surface tension of the foaming agent in the phenolic resin by adjusting the content of the surfactant in the above range with respect to the foaming agent relative to 100 parts by weight of the phenolic resin, so that the foaming agent can be stably dispersed, and in the foaming process It is possible to make the bubbles uniformly formed in an appropriate size. Accordingly, including the specific foaming agent, it is possible to simultaneously exhibit excellent dimensional stability, compressive strength, uniform cell diameter, and the like, as well as sufficiently excellent thermal insulation properties.

The surfactant may be included in the composition in an amount of about 2 parts by weight to about 10 parts by weight based on 100 parts by weight of the phenol-based resin. Specifically, when the content of the surfactant is less than the above range, the foaming agent is not uniformly dispersed on the phenolic resin, it is difficult to form bubbles, and the bubbles are formed non-uniformly, so that the cells are merged or the bubble cells are opened and the independent cell ratio is can be lowered And the low compressive strength can break the cell. When it exceeds the above range, the viscosity of the composition may be lowered to promote vaporization of the foaming agent, and accordingly, the content of the foaming agent contained in the bubbles is decreased compared to the amount of the injected foaming agent, so that there may be a problem in that thermal insulation properties and the like are lowered.

The phenolic foam includes a curing agent. The curing agent may include one acid curing agent selected from the group consisting of toluene sulfonic acid, xylene sulfonic acid, benzenesulfonic acid, phenol sulfonic acid, ethylbenzene sulfonic acid, styrene sulfonic acid, naphthalene sulfonic acid, and combinations thereof. The acid curing agent may be included in an amount of about 9 parts by weight to about 20 parts by weight, based on 100 parts by weight of the phenol-based resin. The phenol foam may exhibit appropriate crosslinking, curing and foaming properties by including the curing agent.

The foaming composition may include the foaming agent: the curing agent in a weight ratio of about 1: 1.1 to about 1: 3.5. For example, it may be included in a weight ratio of about 1: 2.2 or about 1: 2.35 to about 1: 3.5. Accordingly, excellent physical properties can be imparted to the foam by well controlling the balance between foaming and curing. For example, when the content of the curing agent is less than the above range, there may be problems in that the curing rate is slowed compared to the foaming rate, and the maximum foaming pressure is lowered. And, when the content of the curing agent exceeds the above range, the curing proceeds quickly before forming a sufficient foaming pressure, and as post-foaming is made, problems such as cracks in the foam may occur.

The foaming composition may be stirred at a speed of 100 rpm to 1,500 rpm. In the manufacturing method, the amount of heat generated by mixing shear stress can be adjusted by stirring the foaming composition at a speed within the range, and thus the foaming ratio can be appropriately adjusted. Specifically, when the stirring speed is less than the above range, the stirring is not uniformly made, so it is difficult to fill 100% of the foam in the mold and the curing furnace, and therefore the foam is not formed uniformly, resulting in thermal insulation performance, compressive strength and dimensional stability. There may be a problem of deterioration of physical properties. When the stirring speed exceeds the above range, the shear stress caused by the stirring speed is excessively applied, and the temperature of the composition increases, so that foaming occurs rapidly and the foaming agent volatilizes quickly, so there may be a problem in that the thermal insulation performance is deteriorated.

The foaming composition is stirred in a mixer, and immediately before flowing the foaming composition to a nozzle for discharging the foaming composition, the mixer may have a temperature of about 20°C to about 50°C. or from 33°C to about 48°C. By adjusting the temperature of the mixer to the above range, the balance between foaming and curing can be appropriately adjusted to improve the physical properties of the foam. For example, when the temperature of the mixer is less than the above range, foaming is made, but sufficient heat is not supplied, so the curing rate is very slow, and this causes the foaming agent to escape to the outside without being in the foam. Accordingly, the strength of the foam may decrease and thermal conductivity may deteriorate at the same time. In addition, when the temperature of the mixer exceeds the above range, the curing rate becomes too fast before the shape is taken through foaming, so that the shape of the foam may not completely fill the inside of the mold. Accordingly, an appearance defect and physical properties may be deteriorated.

The manufacturing method includes discharging the stirred foam composition, foaming and curing. In this case, the foaming and curing may be performed at 40°C to 70°C. Foaming and curing at a temperature in the above range allows the foam to be well filled in the mold or curing furnace, and it is easier to prevent the foaming pressure from increasing in the second half to increase the size of the foam and to lower the foam properties. The above temperature refers to the temperature in the mold or curing furnace. When the temperature is less than the above temperature, the expansion ratio does not rise, the initial thermal insulation performance may be lowered, and the foam is not formed, such as in the form of a foaming mold and curing furnace. there may be And, when it exceeds the above range, there may be a problem in that the bubbles in the foam may burst and the thermal conductivity and the closed cell ratio are lowered.

The foam composition may move at a speed of about 3 m/min to about 20 m/min in a curing furnace having a thickness of about 30 m to about 200 m. For example, it can move at a speed of about 5 m/min to 15 m/min. The foaming composition may be moved in a ratio of about 2:1 to about 60:1 thickness (m) of the foaming composition to the curing furnace: moving speed (m/min) of the foaming composition. By moving the foaming composition in the curing furnace at a speed in the above range, the temperature and distribution of heat accumulated inside the foam and the foaming pressure are controlled, and thus the balance with the curing speed can be adjusted to improve the physical properties of the foam. there is. For example, when the speed is less than the above range, the heat inside the foam is too high to cause over-foaming and cause the cells close to the surface to burst. Accordingly, strength and thermal conductivity may be reduced. And, when it exceeds the above range, sufficient heat is not provided to the foam, so that curing may not be completed completely, and problems such as dimensional stability and warpage after curing may occur. For example, the foaming composition is or)

(Example)

Example 1:

100 parts by weight of a resol resin having a moisture content of 10% by weight (20°C, viscosity 15,000cps), 20 parts by weight of toluene sulfonic acid, 8.5 parts by weight of a foaming agent, and 5 parts by weight of a castor oil-based surfactant (Polyoxyethylene caster oil) of HLB 13 were prepared . As the foaming agent, a foaming agent obtained by mixing cyclopentane to isopropyl chloride in a weight ratio of 4:6 (average boiling point: 41.2°C, difference in boiling point (Δ)=13°C) was prepared.

Then, the resol resin, the foaming agent and the surfactant were mixed, aged at room temperature (about 25° C.) for about 2 hours, and then the curing agent was added to prepare a foaming composition. Then, the foaming composition was stirred at 1,000 rpm, so that the temperature of the mixer was 38°C. Thereafter, the foaming composition was discharged on the face material, and foamed and cured while moving at a speed of 10 m/min in a curing furnace heated to an average internal temperature of 65° C. to prepare a phenolic foam having a thickness of 90 mm. At this time, the foaming agent was included in about 8 parts by weight based on 100 parts by weight of the foam.

Example 2:

The phenol foam was formed in the same manner as in Example 1, except that a foaming agent (average boiling point: 40.6°C, boiling point difference (Δ)=13°C) mixed with cyclopentane to isopropyl chloride in a weight ratio of 3.5:6.5 as the foaming agent was used. was prepared.

Example 3:

A phenol foam was formed in the same manner as in Example 1, except that a foaming agent mixed with cyclopentane to isopropyl chloride in a weight ratio of 3:7 (average boiling point: 39.9° C., difference in boiling point (Δ)=13° C.) was used as the foaming agent. was prepared.

Comparative Example 1:

The phenol foam was formed in the same manner as in Example 1, except that a foaming agent mixed with cyclopentane to isopropyl chloride in a weight ratio of 6:4 (average boiling point: 43.8°C, boiling point difference (Δ)=13°C) was used as the foaming agent. was prepared.

Comparative Example 2:

A phenol foam was prepared in the same manner as in Example 1, except that a foaming agent mixed with cyclopentane to isopentane in a weight ratio of 4:6 (average boiling point: 35.6° C., boiling point difference (Δ) = 22° C.) was used as the foaming agent. prepared.

Comparative Example 3:

Phenolic foam in the same manner as in Example 1, except that a foaming agent (average boiling point: 48.2°C, boiling point difference (Δ)=53°C) mixed with cyclohexane to isopropyl chloride in a weight ratio of 4:6 as the foaming agent was used. was prepared.

Comparative Example 4:

Phenol in the same manner as in Example 1, except that a foaming agent mixed with cyclohexane to n-butyl chloride in a weight ratio of 4:6 (average boiling point: 79.4° C., difference in boiling point (Δ)=2.3° C.) was used as the foaming agent. A foam was prepared.

evaluation

Experimental Example 1: Deviation of average bubble diameter and bubble diameter

Examples and Comparative Examples To include the central portion of the phenolic foam in the center, a specimen having a size of 10 mm (L) Χ 10 mm (W) Χ 30 mm (T) was prepared. Then, after making a cut in the center of the thickness direction of the specimen and freezing with liquid nitrogen, the thickness direction of the specimen was cut in half so as to be parallel to the surface of the foam and perpendicular to the thickness direction. Accordingly, the central portion (middle center) of the foam was placed on the surface of the cut surface, and after obtaining a picture of the cut surface by SEM, the size of each of 100 cells was measured using an image analysis tool. And the average and standard deviation were calculated and the results are shown in Table 1 below.

Experimental Example 2: Water absorption rate (%)

The phenolic foams of Examples and Comparative Examples were dried at a temperature of 25±5° C. and a humidity of 50±10% for at least 12 hours. Then, the phenolic foam was cut with a band saw to prepare a specimen having a width of 15 cm, a length of 15 cm, and a height of 4 cm. At this time, the specimen was prepared by cutting so as to be obtained at the central portion of the phenolic foam.

The weight change rate according to the water absorption of the specimen, that is, the water absorption rate was measured according to KS M ISO 2896 standard, and calculated by Equation 1 below, and the results are shown in Table 1 below.

[Equation 1]

Specifically, the moisture absorption rate was measured using the apparatus shown in FIG. 2 . In Equation 1, WAv is the water absorption rate (%) of the foam, m1 is the initial weight of the foam 20 itself before immersion in water, m2 is the weight of the mesh 10 itself for containing the foam . The mesh 10 on which the foam 20 is placed is hung on the mesh hanger 40 , and the mesh 10 is immersed in the water tank 50 using a weight 30 . m3 is the weight of the foam 20 and the mesh 10 in water after being immersed in water in the water tank 50 for 96 hours using the measuring scale 60, and V ₀ is The volume of the foam 20 before immersion in water, V ₁ is the volume of the foam 20 after immersion in water for 96 hours, Vc is the bubble located on each side of the foam 20 and observed from the outside The volume of, ρ, refers to the density of water into which the foam is immersed.

Experimental Example 3: Dimensional Stability (%)

1 is a schematic diagram briefly showing a method for measuring the dimensional stability of the phenolic foam of the present invention. The phenolic foams of Examples and Comparative Examples were prepared as specimens having the same thickness as the foam including 100mm (L)Х100mm (W)Хface material. And, as shown in FIG. 1, parallel lines are drawn at n (n=3) equal points in the length (L) and width (W) directions of the specimen, respectively, and the initial length (a) of each line at 25°C ) was measured.

Then, the later length (a') of each point is measured after the specimen is left in an oven at 70° C. for 48 hours, and the dimensional change rate (%) changed from the initial dimension is measured by Equation 1 below, and the average value is Table 1 shows. Dimensional stability was measured by the method of KS M ISO 2796 standard.

[Equation 1]

Dimensional change rate (%) = (initial length (a) - later length (a')) / initial length (a) X 100

In Equation 1, the initial length (a) is the length of each line of n equal points in the length (L) and width (W) directions of the foam, and the later length (a') is the foam at 70° C. It means the later length (a') of each line at each point after standing in the oven for 48 hours. In this case, n may be 2 to 5.

Experimental Example 4: Compressive strength (kPa)

The phenolic foams of Examples and Comparative Examples were prepared as specimens with the same foam thickness including 50 mm (L) Х50 mm (W) Х face materials, and the specimens were placed between the wide plates of Lloyd Instrument's LF Plus universal testing machine (Universal Testing Machine). In the UTM equipment, the speed was set at 10%/min of the thickness of the specimen, and the compressive strength test was started, and the maximum load reached while the thickness was reduced was recorded. Compressive strength was measured by the method of KS M ISO 844 standard, and the results are shown in Table 1 below.

Experimental Example 5: Initial thermal conductivity (W/m·K)

While cutting the phenolic foams of Examples and Comparative Examples to be 50 mm from any one surface, a specimen was prepared by cutting it to a size of 300 mmХ300 mm, and the specimen was dried at 70° C. for 12 hours and pre-treated. And, according to the measurement conditions of KS L 9016 (plate heat flow metering method) for the specimen, the thermal conductivity was measured using a HC-074-300 (EKO company) thermal conductivity instrument at an average temperature of 20° C., and the results are shown in the table below. 1 is described.

Experimental Example 6: Long-term thermal conductivity (W/m·K)

Specimens were prepared by cutting the phenolic foams of Examples and Comparative Examples to a size of 300 mmХ300 mm while cutting to a length of 50 mm from either surface, and the specimens were dried at 70° C. for 7 days according to EN13823 and then at 110° C. After drying for 14 days, the thermal conductivity was measured using a thermal conductivity instrument HC-074-300 (EKO) at an average temperature of 20° C., and the results are shown in Table 1 below.

Average
bubble diameter Deviation of cell diameter moisture
absorption rate
(%) size
stability
(%) compressive strength
(kPa) Early
thermal conductivity long time
thermal conductivity Example 1 110.4 17.2 2.3 0.63 165 0.0184 0.0201 Example 2 108.8 17.0 2.5 0.69 155 0.0182 0.0201 Example 3 106.7 16.7 2.4 0.75 151 0.0181 0.0202 Comparative Example 1 137.9 26.9 4.1 1.03 133 0.0201 0.0231 Comparative Example 2 180.2 33.3 4.2 1.05 97 0.0225 0.0238 Comparative Example 3 187.1 39.4 4.9 0.98 87 0.0233 0.0289 Comparative Example 4 - - - - - - -

As shown in Table 1, the phenolic foam of the example, unlike the comparative example, while including the hydrocarbon-based foam, uniformly had cells of an appropriate size, low water absorption, excellent compressive strength and dimensional stability, along with improved thermal conductivity It was confirmed that they have at the same time. On the other hand, in the case of Comparative Example 4, it was impossible to measure because the foam was not formed normally.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and a variety of It is obvious that variations can be made. In addition, even if the effect of the configuration of the present invention is not explicitly described and described while describing the embodiment of the present invention, it is natural that the effect predictable by the configuration should also be recognized.

10: mesh
20: foam
30: weight
40: net hanging place
50: tank
60: measuring mirror

Claims (12)

a blowing agent comprising a first blowing agent and a second blowing agent;
The first blowing agent is a cyclic alkane having 6 or less carbon atoms, and the second blowing agent is a linear or branched chlorinated aliphatic alkane having 3 to 6 carbon atoms,
The second blowing agent comprises more than the first blowing agent,
The difference between the boiling points of the first foaming agent and the second foaming agent is 10 °C to 20 °C
phenolic foam.
According to claim 1,
The first blowing agent comprises one selected from the group consisting of cyclobutane, cyclopentane, cyclohexane, and combinations thereof
phenolic foam.
2. The method of claim 1
The second blowing agent comprises one selected from the group consisting of propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride, chlorohexane, and combinations thereof
phenolic foam.
According to claim 1,
The foaming agent including the first foaming agent and the second foaming agent has an average boiling point of 38°C to 43°C.
phenolic foam.
According to claim 1,
The first blowing agent to the second blowing agent comprising a weight ratio of 2:8 to 4.5:5.5
phenolic foam.
According to claim 1,
The average cell diameter in the cross section bisecting the thickness direction of the foam is 80 μm to 130 μm, and the standard deviation of the cell diameter is 10% to 25%
phenolic foam.
According to claim 1,
The average value of the dimensional change rate by the following formula 1 is 0% to 1.0%
Phenolic Foam:

[Equation 1]
Dimensional change rate (%)=[(Initial length (a)-Later length (a'))/Initial length (a)] X 100

In Equation 1, the initial length (a) is the length of each line of n equal points in the length (L) and width (W) directions of the phenolic foam, and the later length (a') is the phenolic foam It means the later length (a') of each line at each point after standing in an oven at 70° C. for 48 hours. (n is 2 to 5)
According to claim 1,
Compressive strength according to KS M ISO 844 is 100 kPa to 300 kPa
phenolic foam.
Preparing a foaming composition comprising a phenol-based resin, a foaming agent, a surfactant and a curing agent, and stirring the foaming composition; and
Including; discharging the stirred foam composition, foaming and curing;
The foaming agent includes a first foaming agent and a second foaming agent,
The first blowing agent is a cyclic alkane having 6 or less carbon atoms, and the second blowing agent is a linear or branched chlorinated aliphatic alkane having 3 to 6 carbon atoms,
The second blowing agent comprises more than the first blowing agent,
The difference between the boiling points of the first foaming agent and the second foaming agent is 10 °C to 20 °C
Method for producing phenolic foam.
10. The method of claim 9,
The moisture content contained in the phenolic resin is 9 wt% to 20 wt%
Method for producing phenolic foam.
10. The method of claim 9,
The stirring speed is 100 rpm to 1,500 rpm
Method for producing phenolic foam.
10. The method of claim 9,
The foaming and curing is carried out at 40 ℃ to 70 ℃
Method for producing phenolic foam.

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