KR20230049171A - Phenolic foam resin composition and eco-friendly phenolic foam using the same - Google Patents

Abstract

The present invention can provide a phenol foam resin composition and an eco-friendly phenol foam using the same. The phenol foam resin composition reduces the content of residual formaldehyde compared to a conventional phenol foam by introducing nanoclay. In addition, the phenol foam resin composition can maintain a high level of flame retardancy, excellent mechanical properties, and thermal insulation properties. The phenol foam resin composition includes: a phenolic resin; a blowing agent; a curing a gent; and nanoclay.

Description

Phenolic foam resin composition and eco-friendly phenolic foam using the same

The present invention relates to a phenolic foam resin composition and a phenolic foam using the same, and specifically, by introducing nanoclay, the content of residual formaldehyde is reduced compared to conventional phenolic foam, while maintaining a high level of flame retardancy, excellent mechanical properties and heat insulation It relates to a phenolic foam resin composition and an eco-friendly phenolic foam using the same.

Recently, as large-scale fires have occurred one after another, public interest has increased. In particular, there is a problem in that fire suppression is difficult due to the generation of toxic gas or soot in the event of a fire, and as safety regulations for building materials, in particular, insulation materials for interior and exterior decoration of buildings are strengthened, phenolic foam is attracting attention among insulation materials for interior and exterior decoration of buildings.

Phenol foam is a type of organic insulation material, and is a thermosetting plastic foam obtained by foaming and curing a phenolic resin having excellent thermochemical stability. These phenolic foams are not only excellent in flame retardancy, heat insulation, heat resistance and low fumes, but also are in the limelight as they satisfy the standards for flame retardant materials in each country. In addition, phenolic foam is known as the safest organic plastic material against flames because it generates less smoke or harmful gases in the event of a fire. In addition, phenolic resin, a raw material of phenolic foam, has excellent mechanical properties at high temperatures and shows a high residual carbonization rate even when exposed to high temperatures for a long period of time. outstanding.

Such phenolic foam is usually prepared by mixing components such as a plasticizer, a curing agent, and a flame retardant with a phenolic resin, followed by foaming and curing. At this time, a resol-type phenolic resin is mainly used as the phenolic resin. In general, resol-type phenolic resins are prepared by reacting phenols with aldehydes (eg, formaldehyde), and at this time, phenols and reactive aldehydes are usually added in excess to synthesize them. For this reason, the aldehydes remaining after the reaction are not completely removed, and odors are generated in the phenol foam production process, and the aldehyde gas remaining in the phenol foam spreads in the air, adversely affecting the environment or human body. In particular, among aldehydes, formaldehyde irritates the nose and eyes with a very irritating odor, is a toxic substance harmful to humans and the natural environment, and has recently been suspected of being a carcinogen and is attracting worldwide interest. Regulations on the amount of formaldehyde are being tightened. Therefore, various studies and efforts are being made to reduce the amount of formaldehyde remaining in the phenol foam.

In this regard, a technique for reducing the amount of residual formaldehyde by adjusting the ratio of formaldehyde and phenol resin to a low level when synthesizing a resol-type phenolic resin has been disclosed. However, in this case, the thermal insulation and mechanical properties of the final phenolic foam were inevitably reduced. In addition, a large amount of catalyst was used when synthesizing a resol-type phenolic resin, but in this case, excessive heat generation occurred, making it difficult to control the process. In addition, an attempt was made to reduce the amount of residual formaldehyde by using urea, etc., but in this case, the heat resistance and quasi-incombustibility of the final phenolic foam were reduced.

Accordingly, there is a need for a technique capable of reducing the amount of residual formaldehyde while preventing deterioration of heat insulation, mechanical properties, heat resistance and quasi-incombustibility of phenol foam.

Korean Registered Patent No. 10-1892057

The present invention has been made to solve the above problems, as a technical problem to provide a phenolic foam resin composition having low human and environmental hazards, including nanoclay, and excellent residual formaldehyde removal efficiency.

In addition, the present invention is another technical problem to provide an eco-friendly phenolic foam capable of maintaining a low level of residual formaldehyde, excellent insulation performance, mechanical properties, heat resistance, and flame retardancy using the above-described phenolic foam resin composition, and an insulation material using the same do it with

Other objects and advantages of the present invention can be more clearly described by the following detailed description and claims.

In order to achieve the above technical problem, the present invention is a phenolic resin; blowing agent; curing agent; and nanoclay, wherein the nanoclay is included in an amount of 1 to 20 parts by weight based on 100 parts by weight of the phenolic resin.

In one embodiment of the present invention, the nanoclay may be an inorganic material having a layered structure.

In one embodiment of the present invention, the nanoclay may have an average particle diameter (D50) of 0.1 to 1,000 μm, a long aspect ratio of 0.1 to 10, and an interlayer distance of 1 to 100 Å.

In one embodiment of the present invention, the nanoclay is montmorillonite, bentonite, hectorite, saponite, beidelite, nontronite, mica, vermiculite, carnemite, magadite, kenite, kaolinite, smectite, il It contains at least one selected from the group consisting of light, chlorite, muscobite, pyrophyllite, antigolite, sepiolite, imogolite, sobokite, nacrite, anoxite, sericite, and reddicite. can

For one embodiment of the present invention, the phenolic resin includes a polymer of phenol and aldehyde-based compound, and the molar ratio of the phenol and the aldehyde-based compound may be 1:1.2 to 3.6.

For one embodiment of the present invention, the phenolic resin, 500 to 2,000 weight average molecular weight (Mw) in g/mol; and a moisture content of 3 to 15%.

For one embodiment of the present invention, the foaming agent may contain at least one selected from the group consisting of hydrocarbon-based foaming agents and halogenated hydrocarbon-based foaming agents.

For one embodiment of the present invention, the curing agent may be an acid curing agent.

For one embodiment of the present invention, one or more selected from the group consisting of a plasticizer, a surfactant and a flame retardant may be further included.

In addition, the present invention provides a phenolic foam in which the above-described phenolic foam resin composition is foamed and cured.

For one embodiment of the present invention, the phenol foam may have a residual formaldehyde content of less than 50 mg/kg.

In addition, the present invention provides a heat insulating material comprising the above-described phenolic foam.

The phenolic foam resin composition according to the present invention realizes a high level of flame retardant / semi-nonflammable performance while reducing the residual formaldehyde level compared to conventional phenolic foam, and simultaneously secures and maintains high mechanical properties and excellent insulation properties. can provide

Effects according to the present invention are not limited by the contents exemplified above, and more diverse effects are included in the present specification.

Hereinafter, the present invention will be described in detail. However, it is not limited only by the contents below, and each component may be variously modified or optionally mixed as needed. Therefore, it should be understood to include all modifications, equivalents or substitutes included in the spirit and scope of the present invention.

All terms (including technical and scientific terms) used in this specification, unless otherwise defined, may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

In addition, throughout this specification, when a certain component is said to "include", it means that it may further include other components, not excluding other components, unless otherwise stated.

<Phenol foam resin composition>

The phenolic foam resin composition according to an embodiment of the present invention is a foaming composition for forming a phenolic foam usable as a heat insulating material, and is distinguished from the prior art in that nanoclay is specifically introduced.

Such nanoclay can provide eco-friendly nanoclay reinforced phenolic foam by simultaneously serving as a scavenger that captures and adsorbs and removes residual formaldehyde and as a reinforcing material that reinforces the mechanical properties of the final foam.

For one specific example, the phenolic foam resin composition is a phenolic resin; blowing agent; curing agent; and nanoclay, and includes the nanoclay within a predetermined range. If necessary, at least one or more of a plasticizer, a surfactant, a flame retardant, and other additives may be further included.

Hereinafter, looking at each component constituting the phenol foam resin composition according to the present invention are as follows.

phenolic resin

In the phenol foam resin composition according to the present invention, the phenolic resin is a thermosetting resin produced by reacting phenols and aldehydes, and a conventional acid and/or base catalyst known in the art may be used as a reaction catalyst. At this time, when an acid catalyst is used, a novolac-type phenolic resin is prepared, and a base catalyst (eg, alkali metal hydroxide such as lithium hydroxide and potassium hydroxide; alkaline earth metal hydroxide such as barium hydroxide) is used. In this case, a resol-type phenolic resin is prepared. Examples of usable phenolic resins include resol-type phenolic resins, novolac-type phenolic resins, or mixtures thereof.

For example, the phenol-based resin may be a resol-based resin in which phenol and an aldehyde-based compound are polymerized in the presence of a catalyst.

Non-limiting examples of usable phenolic compounds include phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, resorcinol, or mixtures thereof. In addition, non-limiting examples of the aldehyde-based compound include formaldehyde, formalin, paraformaldehyde, furfural, acetaldehyde, or mixtures thereof.

At this time, the molar ratio of phenol and aldehyde can be appropriately adjusted within a content range known in the art, and it is preferable to add an excess amount of aldehyde to reduce unreacted phenol and aldehyde. For example, the molar ratio between phenol and aldehyde-based compounds may be 1:1.2 to 3.6, specifically 1:1.5 to 3.0.

In addition, in order to remove unreacted aldehyde, urea or melamine may be added to the remaining amount of aldehyde and reacted. At this time, the amount of urea or melamine added is not particularly limited, and may be, for example, 10 to 70 parts by weight based on 100 parts by weight of aldehyde.

The viscosity of the phenolic resin is not particularly limited, but the lower the viscosity of the phenolic resin, the easier it is to control the phenolic resin in the process. Accordingly, the viscosity of the phenolic resin may be about 80,000 cPs or less, specifically about 5,000 to 80,000 cPs, more specifically about 10,000 to 70,000 cPs, and even more specifically about 20,000 to 60,000 cPs at about 25 °C. According to one example, the phenolic resin may have a viscosity of about 40,000 to 55,000 cPs.

In addition, the phenolic resin may contain about 3 to 15% of moisture. If the moisture contained in the phenolic resin is less than 3%, the viscosity of the resin increases and it is difficult to control the process, while if the moisture contained in the phenolic resin exceeds 15%, the physical properties of the final phenolic foam are lowered, Thermal conductivity may increase.

In addition, the weight average molecular weight (Mw) of the phenolic resin may be in the range of about 500 to 2,000 g/mol. If the weight average molecular weight of the phenolic resin is less than about 500 g / mol, the density and mechanical strength of the phenolic foam may decrease, while if the weight average molecular weight of the phenolic resin exceeds about 2,000 g / mol, the viscosity Elevation can make process operations difficult.

The content of the phenolic resin is not particularly limited, and according to an example, it may range from about 50 to 95% by weight based on the total amount of the phenolic foam resin composition. When the content of the phenol-based resin is within the above-mentioned range, it is possible to improve the insulation properties without deteriorating the physical properties of the phenolic foam and increasing the thermal conductivity.

nanoclay

In the phenolic foam resin composition according to the present invention, the nanoclay material serves as a scavenger for trapping and adsorbing and removing residual formaldehyde used as a raw material in the production of conventional phenolic resin and a reinforcing material for reinforcing the mechanical properties of the final foam can play a role

As the nanoclay, inorganic materials having a conventional layered structure known in the art may be used without limitation. Such inorganic layered nanoclay can exhibit the effect of removing and reducing residual formaldehyde by trapping/adsorbing residual formaldehyde in the microscopic spaces between the layered structures, and also contributes sufficiently to maintaining mechanical properties, heat resistance, and semi-incombustibility as an inorganic additive. there is.

The nanoclay according to the present invention may be a plate-shaped clay mineral.

For one specific example, the average particle diameter (D ₅₀ ) of the nanoclay may be 0.1 to 1,000 μm, and more specifically, 0.5 to 50 μm. When the average particle diameter of the nanoclay is within the above range, it may have the advantage of being homogeneously mixed in the foaming mixture. Specifically, when the average particle diameter of the nanoclay is less than 1 μm, most of the nanoclay floats on the top of the foam mixture, and when it exceeds 1,000 μm, most of the nanoclay settles on the bottom of the foam mixture, which may cause a problem of deterioration in uniformity.

For another specific example, the long aspect ratio of the nanoclay may be 0.1 to 10, specifically 0.5 to 2.5. When the long diameter of the nanoclay is within the above range, it may have the advantage of being able to efficiently capture formaldehyde. Specifically, when the long aspect ratio of the nanoclay is less than 1, formaldehyde capture is reduced due to space narrowing, and when it exceeds 10, there may be a problem in that the space-to-capture efficiency is lowered.

For another specific example, the interlayer distance of the nanoclay may be 1 to 100 Å, specifically 5 to 25 Å. When the interlayer distance of the nanoclay is within the above range, formaldehyde can be efficiently captured. Specifically, when the interlayer distance of the nanoclay is less than 1 Å, formaldehyde capture due to the narrow space is reduced, and when it exceeds 100 Å, there may be a problem in that the capture efficiency is lowered compared to the space.

When the nanoclay according to an example of the present invention satisfies the above-described average particle diameter, long diameter, and / or interlayer distance parameters, the homogeneity of the mixture and the capture efficiency of formaldehyde are improved, resulting in a synergistic effect in terms of physical properties of the final phenolic foam ( synergy effect).

Non-limiting examples of nanoclay materials that can be used include montmorillonite, bentonite, hectorite, saponite, beidelite, nontronite, mica, vermiculite, carnemite, magadite, kenite, kaolinite, smectite, illite. , chlorite, muscobite, pyrophyllite, antigolite, sepiolite, imogolite, sobokite, nacrite, anoxite, sericite, redicite, or combinations thereof, and the like.

In the phenol foam resin composition of the present invention, the content of the nanoclay material is not particularly limited, and may be appropriately adjusted within a range known in the art. For example, nanoclay may be used in an amount of 1 to 20 parts by weight, specifically 3 to 10 parts by weight, based on 100 parts by weight of the phenolic resin. When the content of the nanoclay is lower than the above range, flame retardancy is lowered, and when it exceeds the above range, heat insulating properties and physical properties of the phenol foam are lowered, and process control becomes difficult due to an increase in viscosity.

blowing agent

In the phenolic foam resin composition according to the present invention, the foaming agent is a component added to facilitate foaming of the phenolic resin, and is not particularly limited as long as it is used for foaming of phenolic foam in the art. For example, the blowing agent includes a hydrocarbon-based blowing agent, a halogenated hydrocarbon-based blowing agent, or a combination thereof, but is not limited thereto.

The hydrocarbon-based compound usable in the present invention is a hydrocarbon having 1 to 6 carbon atoms, such as n-butane, isobutane, n-pentane, isopentane, cyclopentane, and n-hexane, but is not limited thereto.

Halogenated hydrocarbon-based compounds usable in the present invention are halogen-substituted hydrocarbons having 1 to 6 carbon atoms, for example, chlorinated hydrocarbons such as isopropyl chloride, dichloroethane, propyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, and isopentyl chloride. ; fluorinated hydrocarbons such as chlorinated hydrofluoroolefin compounds and non-chlorinated hydrofluoroolefin compounds; brominated hydrocarbons; There are iodine-based hydrocarbons, etc., but it is not limited thereto. These may be used alone or in combination of two or more.

In addition, a foaming agent having an ozone depletion potential (ODP) of 0.11 or less may be used, preferably 0.

In the phenol foam resin composition of the present invention, the content of the foaming agent is not particularly limited, for example, about 2 to 20 parts by weight, specifically about 2 to 15 parts by weight, more specifically about 5 to 10 parts by weight, based on 100 parts by weight of the phenolic resin. It may be part by weight. If the content of the foaming agent is less than about 2 parts by weight, the thermal conductivity of the phenolic foam may increase and the insulation properties may be deteriorated. On the other hand, if the content of the foaming agent exceeds about 20 parts by weight, the density of the phenolic foam is reduced and mechanical properties are deteriorated. can

curing agent

The phenol foam resin composition according to the present invention may further include a conventional curing agent known in the art. The curing agent is a component (curing catalyst) for accelerating the curing reaction of the phenol resin, and includes an acid curing agent.

According to one example, the curing agent may be an acid curing agent. In this case, the starting temperature of the formaldehyde removal reaction by the residual formaldehyde trapping agent may be lowered from about 200 °C to about 70 to 75 °C. Because of this, the present invention can easily remove the remaining formaldehyde with the residual formaldehyde trapping agent even under a phenol foam foaming temperature of about 70 to 75 °C.

Acid curing agents usable in the present invention include aromatic sulfonic acids such as benzene sulfonic acid, phenol sulfonic acid, toluene sulfonic acid, xylene sulfonic acid, ethylbenzene sulfonic acid, and naphthalene sulfonic acid; aliphatic sulfonic acids such as methane sulfonic acid and trifluoromethane sulfonic acid; There are inorganic acids, such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, but are not limited thereto. These may be used alone or in combination of two or more. Among them, phenol sulfonic acid, toluene sulfonic acid, xylene sulfonic acid, naphthalene sulfonic acid and the like can improve the curing speed of phenolic resins.

The content of the curing agent is not particularly limited, but if the content of the curing agent is too small, the curing of the phenolic resin is delayed or not cured, resulting in a decrease in production rate, a uniform and robust closed cell structure, and, of course, phenolic foam. The mechanical properties of the may be lowered and the thermal conductivity may be increased. On the other hand, if the content of the curing agent is too large, the pH of the phenolic foam may be lowered (acidic curing), which may increase corrosiveness, and foaming may proceed immediately after spraying the resin composition, thereby reducing productivity of the product. Therefore, it is appropriate to adjust the content of the curing agent within the range of about 2 to 20 parts by weight, specifically about 2 to 15 parts by weight, and more specifically about 5 to 10 parts by weight based on 100 parts by weight of the phenolic resin.

flame retardant

The phenol foam resin composition according to the present invention may further include a flame retardant. The flame retardant is a component that imparts flame retardancy and quasi-incombustibility to the phenolic foam, and is not particularly limited as long as it is generally used in the art.

Available flame retardants include halogen-based, phosphorus-based, halogen-phosphorous, boron-based flame retardants, metal hydroxides, expandable graphite, red, water glass, and the like. Specific examples of the flame retardant include TCPP (Tris (1-Chloro-2- Propyl) Phosphate), TEP (Triethyl Phosphate), TEPP (Tetraethyl piperazine-1,4-diyldiphosphoramidate), halogen-substituted aromatic polyols (ISOEXTER-3644, etc.), TCP(Tricresyl Phosphate), RDP(Resorcinol bis(diphenyl phosphate)), APP(Ammonium Poly Phosphate), DOPO-HQ(10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-xa-10-phosphaphenanthrene -10-oxide), phosphazene system, expanded graphite, red, boric acid (H ₃ BO ₃ ) and borax (Na ₂ B ₄ O ₇ ), aluminum hydroxide, water glass, and the like, but are not limited thereto. These may be used alone or in combination of two or more.

The amount of the flame retardant is not particularly limited, and may be, for example, about 1 to 20 parts by weight, specifically about 2 to 15 parts by weight, and more specifically about 2 to 10 parts by weight, based on 100 parts by weight of the phenolic resin. When the content of the flame retardant is less than about 1 part by weight, the flame retardancy of the phenol foam may be insufficient, while when the content of the flame retardant exceeds about 20 parts by weight, the physical properties of the phenol foam are lowered or the viscosity of the resin composition is high, resulting in a manufacturing process. It is difficult to control, and this can reduce production efficiency.

plasticizer

The phenol foam resin composition according to the present invention may further include a plasticizer. The plasticizer can improve the durability of the phenolic foam by preventing the foaming gas from being replaced with air by being released from the bubbles formed in the phenolic foam.

The plasticizer usable in the present invention is not particularly limited as long as it is commonly used in the art, and examples thereof include esters, ester polyols, ether polyols, phosphorus compounds, epoxy resins, and fluorine-based compounds. These may be used alone or in combination of two or more.

The content of these plasticizers is not particularly limited, but if the plasticizer is too small, the flexibility of the phenolic foam may be reduced, while if the plasticizer is too large, mechanical properties or flame retardancy of the phenolic foam may be reduced. Therefore, when the content of the plasticizer is adjusted within the range of about 2 to 30 parts by weight, specifically about 2 to 15 parts by weight, and more specifically about 5 to 10 parts by weight based on 100 parts by weight of the phenolic resin, the flexibility of the phenolic foam, Overall mechanical properties and flame retardancy can be improved.

Surfactants

The phenol foam resin composition according to the present invention may further include a surfactant. The surfactant may increase the hydrophobicity of the phenolic foam while allowing the cells of the phenolic foam to be uniformly formed in a constant size as a whole.

The surfactant usable in the present invention is not particularly limited as long as it is generally used in the art, and examples thereof include siloxane-based compounds, castor oil-ethylene oxide, ester compounds, ether compounds, silicone-based compounds, and fluorine-based compounds. These may be used alone or in combination of two or more.

The content of the surfactant is not particularly limited, but if the content of the surfactant is too small, the size of the cells in the phenol foam may not be constant or the water permeability may increase, while if the content of the surfactant is too large, the physical properties of the phenol foam This may decrease and the thermal conductivity may increase. Accordingly, the content of the surfactant may be about 2 to 20 parts by weight, specifically about 2 to 15 parts by weight, and more specifically about 2 to 10 parts by weight based on 100 parts by weight of the phenolic resin.

additive

In addition to the above components, the phenol foam resin composition of the present invention may use at least one additive known in the art without limitation within a range that does not impair the effect of the present invention.

Examples of usable additives may include nucleating agents, emulsifiers, foam stabilizers, neutralizers, antioxidants, fillers, crosslinking agents, chain extenders, solvents, and the like. These may be used alone or in combination of two or more. At this time, the content of the additive may be appropriately adjusted within a range known in the art, for example, 0.01 to 10 parts by weight, specifically 0.01 to 5 parts by weight based on the total weight of the phenol foam composition.

The phenolic foam resin composition according to the present invention is a mixture of the above-described phenolic resin, nanoclay, curing agent, foaming agent, plasticizer, surfactant, flame retardant, and other additives or solvents mixed as necessary according to a conventional method known in the art. And it can be prepared by stirring.

The phenol foam resin composition of the present invention configured as described above, based on 100 parts by weight of the phenolic resin, includes 1 to 20 parts by weight of nanoclay, 2 to 20 parts by weight of a curing agent, and 2 to 20 parts by weight of a foaming agent, optionally 2 to 30 parts by weight of a plasticizer, 2 to 20 parts by weight of a surfactant, and 1 to 20 parts by weight of a flame retardant may be further included. If necessary, a residual amount of solvent or other additives may be further included to satisfy a total of 100 parts by weight.

<Phenol Foam>

Another example of the present invention is a phenolic foam made of the above-described phenolic foam resin composition.

Specifically, the phenol foam is a foamed cured product prepared by foaming and curing the above-described phenol foam resin composition, and has a low content of residual formaldehyde of less than 50 mg/kg due to capture/adsorption of residual formaldehyde by nanoclay. In addition, phenolic foam has excellent physical properties such as thermal conductivity, compressive strength, bending load, density, water absorption rate, and water vapor permeability, and may have a closed cell structure.

For example, the phenol foam may satisfy at least one or more of the following conditions (i) to (ix), while the content of residual formaldehyde is less than 50 mg / kg, specifically 3 or more, more specifically 5 or more can be satisfied. Preferably, all of the physical properties of (i) to (ix) are satisfied.

(i) a limiting oxygen index (LOI) greater than or equal to 40%;

(ii) the total heat release is less than 8.0 MJ/m2 (based on 10 minutes),

(iii) a thermal conductivity of 0.015 to 0.022 W/m K;

(iv) a compressive strength of 40 to 250 kpa;

(v) a flexural breaking load of 15 to 40 N;

(vi) a water absorption rate of 1.0 to 10.0%;

(vii) a water vapor permeability of 3.0 to 20.0 ng/m s Pa;

(viii) a density of 30 to 50 kg/m 3 ,

(ix) The closed cell rate is 60 to 99%.

Various physical properties of the above-described phenolic foam can be further specified as follows. However, it is not limited thereto.

(i) a limiting oxygen index (LOI) of 40 to 60%;

(ii) The total heat released is 1.0 or more and less than 8.0 MJ/m2 (based on 10 minutes),

(iii) a thermal conductivity of 0.017 to 0.022 W/m K;

(iv) a compressive strength of 50 to 150 kpa;

(v) a flexural breaking load of 20 to 35 N;

(vi) a water absorption rate of 1.0 to 7.0%;

(vii) a water vapor transmission rate of 3.0 to 15.0 ng/m s Pa;

(viii) a density of 30 to 45 kg/m 3 ,

(ix) The closed cell rate is 70 to 99%.

This phenolic foam has excellent insulation properties, high mechanical properties and excellent flame retardancy, and can be used as an eco-friendly building material due to low human and environmental hazards.

Phenolic foam according to the present invention may be prepared according to a conventional method known in the art, and is not particularly limited. As an example, it may be prepared by foaming and curing the above-described phenol foam resin composition.

The foaming and curing process may be carried out at room temperature or by heating, and the components of the above-described phenolic foam resin composition may be stirred at a certain speed, then filled in a mold and then foamed and cured under normal pressure or pressure. Alternatively, the stirred phenolic foam resin composition may be foamed and cured by discharging it onto a face member on a continuous conveyor belt. At this time, additives such as a foaming agent and a surfactant may be mixed with the phenolic resin in advance, or may be mixed with the phenolic resin together with the curing agent.

The foaming and curing temperature is not particularly limited, and may be, for example, about 90°C or less, specifically about 50 to 90°C, and more specifically about 60 to 85°C. According to one example, the foaming and curing temperature may be between about 70 and 75°C. In addition, the foaming and curing time may be about 10 to 30 minutes, specifically about 15 to 25 minutes.

Mold usable in the present invention can be used without particular limitation as long as it can release moisture generated during the curing reaction of the phenolic foam resin composition to the outside. The size of this mold can be designed to an appropriate size by a person skilled in the art if necessary.

In addition, the usable face material is not particularly limited as long as it is used in the field. For example, there are non-woven fabrics and fabrics made of natural fibers, synthetic fibers (eg, polyester fibers, polyethylene fibers, etc.) or inorganic fibers (eg, glass fibers), metal plates and metal foils made of metals such as aluminum, and paper. , and these may be used alone or in combination of two or more.

The nanoclay-reinforced eco-friendly phenolic foam of the present invention prepared as described above shows a lower amount of residual formaldehyde than the conventional phenolic foam, and at the same time has high mechanical properties, excellent heat insulation, flame retardancy, and eco-friendliness. Accordingly, the phenolic foam can be applied without limitation to various fields requiring excellent thermal insulation and mechanical properties. For example, sandwich panels for construction, panels for refrigerated warehouses, spray foam for construction, interior materials for ships, pipe covers (cold insulation materials), container boxes, cold storage warehouses, standard boards, and internal/external insulation of tanks such as LNG, LEG, and LPG. It can be usefully used for insulation materials such as materials and insulation materials for LNG transportation pipelines. Specifically, it may be applied for the purpose of a pipe cover.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[Example 1]

1-1. Preparation of phenolic foam resin composition

Formaldehyde/Phenol = 2.25 (mol) NaOH/Phenol 1.7% by weight of a phenolic resin synthesized [molecular weight (Mw): 850 g/mol, moisture: 6.3%, viscosity (25°C): 49,900 cps] 100 parts by weight, foaming agent 7 parts by weight of cyclopentane, 7 parts by weight of ether polyol as a plasticizer, 80 parts by weight of xylenesulfonic acid as a curing agent: 14 parts by weight of a mixture of 20% by weight of ethylene glycol, 3 parts by weight of a silicone surfactant, 7 parts by weight of red phosphorous as a flame retardant 7 parts by weight of montmorillonite (average particle diameter: 1 μm, length ratio: 1.68, interlayer distance: 15 Å) was stirred with nanoclay, and then 2 parts by weight of distilled water was added and stirred to prepare a phenolic foam resin composition.

1-2. Manufacture of phenolic foam

The phenolic foam resin composition prepared in Example 1-1 was put into a mold (size: 400mm X 400mm X 75mm), foamed and cured at about 70 ° C. for 20 minutes, and then the foamed and cured phenolic foam was demolded. Thereafter, the demoulded phenolic foam was aged in an oven at 70 °C for 15 hours to prepare a phenolic foam.

[Example 2]

Phenol foam of Example 2 was carried out in the same manner as in Example 1, except that 7 parts by weight of bentonite (average particle diameter: 36 μm, long aspect ratio: 0.80, interlayer distance: 12 Å) was used instead of 7 parts by weight of montmorillonite as nanoclay. was manufactured.

[Example 3]

Phenol of Example 2 was carried out in the same manner as in Example 1, except that 7 parts by weight of kaolinite (average particle diameter: 35 μm, long aspect ratio: 1.31, interlayer distance: 7.3 Å) was used instead of 7 parts by weight of montmorillonite as nanoclay. A foam was prepared.

[Comparative Example 1]

A phenolic foam of Comparative Example 1 was prepared in the same manner as in Example 1, except that nanoclay was not used.

[Comparative Example 2]

A phenolic foam of Comparative Example 1 was prepared in the same manner as in Example 1, except that 0.5 parts by weight of montmorillonite was used as the nanoclay.

[Comparative Example 3]

A phenolic foam of Comparative Example 1 was prepared in the same manner as in Example 1, except that 25 parts by weight of montmorillonite was used as the nanoclay.

[Comparative Example 4]

A phenolic foam of Comparative Example 1 was prepared in the same manner as in Example 1, except that 7 parts by weight of urea was used instead of 7 parts by weight of montmorillonite as nanoclay.

[Comparative Example 5]

Formaldehyde / Phenol = 1.5 (mol) NaOH / Phenol 1.7% by weight of a phenolic resin synthesized [molecular weight (Mw): 850 g / mol, moisture: 6.3%, viscosity (25 ℃): 49,900 cps] 100 parts by weight were used , A phenolic foam of Comparative Example 1 was prepared in the same manner as in Example 1, except that 7 parts by weight of montmorillonite was not used.

[Experimental Example: Evaluation of physical properties]

Using the phenol foams prepared in Examples 1 to 3 and Comparative Examples 1 to 5, physical properties were measured in the following manner, respectively, and the results are shown in Table 1 below.

(1) Measurement of total heat release (MJ/㎡)

The prepared phenolic foam was cut to a size of 100 mm X 100 mm X 50 mm and then measured using a cone calorimeter according to the KS F ISO 5660-1 method. Specifically, radiant heat was applied for 10 minutes under conditions of a cone heater temperature of 713 ° C, a blower speed of 24 L: / min, and an oxygen concentration of 20.950% by adjusting 50 kW / m 2 radiant heat to measure the total amount of heat released from the specimen.

(2) Measuring the limiting oxygen index (LOI)

The minimum concentration (%) of oxygen required to burn the phenolic foam specimen was measured under the test conditions specified in KS M ISO 4589-2. The measured result was measured as volume % of oxygen in the oxygen and nitrogen mixture.

(3) Thermal conductivity measurement

After cutting the phenolic foam into a size of 300 mm X 300 mm X 50 mm, a specimen was prepared by pretreatment. Thermal conductivity of the prepared specimen was measured using a thermal conductivity measuring device at 20 ° C according to the KS L 9016 test method.

(4) Measurement of compressive strength

A specimen was prepared by cutting the phenol foam into a size of 50 mm X 50 mm X 50 mm. The prepared specimens were measured for compressive strength according to the KS M ISO 844 test method. At this time, the specimen was placed between wide plates of a universal testing machine (UTM), and the compression speed of the UTM was set to 5 mm/min. At this time, the strength of the first compressive yield point appearing while the thickness was reduced after the start of the test was recorded.

(5) Measurement of bending failure load

A specimen was prepared by cutting the phenolic foam into a size of 250 mm X 100 mm X 20 mm. The prepared specimens were measured for bending failure load according to the KS M ISO 1209-1 test method.

Specifically, in order to apply a load to the specimen perpendicularly to the specimen, the specimen was symmetrically placed on the support bar of the universal testing machine (UTM), the pressure bar was lowered, and this position was set as the strain-free point. Thereafter, a load was applied to the specimen while moving the pressure rod at a speed of 10 ± 2 mm / min, and a load (N) corresponding to a bending deformation of the specimen of 20 ± 0.2 mm was recorded. Before the bending deformation reached 20 mm, the breaking load and bending were recorded when the specimen broke.

(6) Measurement of water absorption rate

A specimen was prepared by cutting the phenolic foam into a size of 150 mm X 150 mm X 75 mm. Water absorption of the prepared specimen was measured according to the KS M ISO 2896 test method. At this time, after measuring the initial mass (m1) of the specimen, the specimen was assembled into a net, immersed in water, and then hung on a scale to measure the mass (m2). In this state, after 96 hours have elapsed, the mass (m3) of the net immersed in water is measured, the volume is calculated by measuring the dimensions of the specimen before and after immersion, and the water absorption rate (WAv) (%) is calculated by the following equation Calculated according to 1.

[Equation 1]

(In Equation 1 above,

m1 is the initial mass of the specimen,

m2 is the mass of the specimen immediately after immersion,

m3 is the mass of the specimen after 96 hours,

V ₀ is the volume of the specimen before immersion,

V ₁ is the volume of the specimen after immersion,

ρ is the density of water (1 g/cm3).

(7) Water vapor permeability measurement

A specimen was prepared by cutting the phenolic foam into a size of 150 mm X 150 mm X 25 mm, and then water vapor permeability was measured according to the KS M ISO 1663 test method.

Specifically, after a desiccant was placed on the bottom of the assembly container to a thickness of 20 mm, the specimen was placed at a point where the separation distance from the desiccant was 15 mm. Then, the mass of the specimen was measured at regular intervals for 24 hours under a temperature of 23 ° C and a humidity of 50%. At this time, the mass of the specimen was measured until the average value of 5 consecutively measured mass changes per unit time was within 2%. After measurement, water vapor permeability (WP) (ng/m·s·Pa) was calculated according to Equation 2 below. Here, the average value (G ₁₂ ) of five continuously measured values was calculated according to Equation 3 below.

[Equation 2]

(In Equation 2,

G is the average of 5 G ₁₂ ;

A is the surface area (cm 2 ) of the specimen exposed to humidity;

P is the vapor pressure difference (Pa), which is 1,400 Pa under the above test conditions,

s is the thickness of the specimen (mm)).

[Equation 3]

(In Equation 3 above,

G ₁₂ is the amount of change in mass per unit time (μg/h) obtained by measuring the mass of the specimen twice consecutively;

m2-m1 is the mass difference (μg) between two consecutively measured specimens,

t2-t1 is the time difference between two measurements of the specimen's mass (h).

(8) Density measurement

After preparing a specimen by cutting the phenolic foam into a certain size, the specimen was aged at 70 °C for 10 to 20 hours, and then the density of the specimen was calculated.

(9) Measurement of closed cell rate

After preparing a specimen by cutting the phenolic foam into a size of 25 mm X 25 mm X 25 mm, the closed cell rate of the prepared specimen was measured using a Pycnometer according to the KS M ISO 4590 test method.

(10) Measurement of residual formaldehyde

The content of residual formaldehyde in the phenol foam was measured according to KS K ISO 14184-1 (distilled water extraction method).

Specifically, after weighing 1 g of specimen with an accuracy of 10 mg, each specimen was placed in a 250 ml flask with a stopper, 100 ml of distilled water was added thereto, and then extracted while shaking at 5 minute intervals for 1 hour in a constant temperature water bath at 40 ° C. Solids were removed by filtration. Thereafter, 5 ml of the filtered extract was put into the first test tube, 5 ml of the standard formaldehyde solution was put into the second test tube, and 5 ml of distilled water was put into the third test tube, and 5 ml of acetylacetone was added to the three test tubes, followed by stirring. The three test tubes were maintained in a constant temperature water bath at 40 ° C. for 30 minutes, and then left at room temperature for 30 minutes. Calculated. At this time, the content of residual formaldehyde (FFA) was measured according to Equation 4 below.

[Equation 4]

(In Equation 4 above,

C is the concentration of formaldehyde in the sample extract (mg / L),

W is the mass of the specimen (g).

phenolic foam thermal conductivity
(W/m K) compression
robbery
(kpa) bending fracture
weight
(N) moisture
absorption rate
(%) vapor
Permeability (ng/ms Pa) density
(kg/m3) total discharge
calorie
(MJ/㎡) LOI
(%) Independent
void rate
(%) residue
form
aldehyde
(mg/Kg) Example 1 0.020 95 31 2.6 6.6 37 4.2 48.5 91 45 Example 2 0.019 102 32 2.8 5.9 39 4.5 46.7 89 46 Example 3 0.021 88 29 2.7 7.2 38 4.3 47.8 90 42 Comparative Example 1 0.019 145 46 2.3 5.6 37 28.8 22.3 94 168 Comparative Example 2 0.021 126 31 2.9 7.5 38 16.5 30.2 89 139 Comparative Example 4 0.025 106 26 3.8 8.9 36 17.4 28.1 80 81 Comparative Example 5 0.034 55 13 6.3 12.7 38 4.5 45.2 67 69

As shown in Table 1, the phenolic foam of the present invention containing a predetermined nanoclay had a lower content of residual formaldehyde than the phenolic foam of Comparative Example 1 without nanoclay, especially 50 mg / kg, it was found that the effect was significant in terms of the content of residual formaldehyde.

In addition, the phenolic foams of Examples 1 to 3 have a limiting oxygen index (LOI) of 45% or more, a total release heat of 4.5 MJ / m 2 or less, a thermal conductivity of 0.019 to 0.021 W / m K, and a compressive strength of 88 ~ 102 kpa, with a flexural breaking load of 29 to 32 N, a water absorption of 2.6 to 2.8%, a water vapor permeability of 5.9 to 7.2 ng/m s Pa, a density of 37 to 39 kg/m3, and closed cell Since the ratio was about 90%, it was confirmed that the physical properties of the phenolic foam were excellent.

In contrast, in the case of the phenolic foam of Comparative Example 5, the residual formaldehyde content is relatively low due to the low molar ratio of the aldehyde-based compound contained in the phenolic resin, while the increase in unreacted phenol results in thermal conductivity, compressive strength, and flexural failure. It was found that the overall physical properties such as load, water absorption rate, water vapor permeability, and closed cell rate were poor.

In view of the foregoing, the nanoclay-reinforced phenolic foam according to the present invention not only significantly reduces the content of residual formaldehyde, but also secures a high level of flame retardancy, excellent mechanical properties and thermal insulation properties at the same time.

Claims (13)

phenolic resins; blowing agent; curing agent; and nanoclay,
The nanoclay is included in 1 to 20 parts by weight compared to 100 parts by weight of the phenolic resin, phenol foam resin composition. According to claim 1,
The nanoclay is a layered inorganic material, phenol foam resin composition. According to claim 1,
The nanoclay,
The average particle diameter (D50) is 0.1 to 1,000 μm,
The long cost ratio is 0.1 to 10,
Interlayer distance between 1 and 100 Å Phosphorus, phenol foam resin composition. According to claim 1,
The nanoclay is montmorillonite, bentonite, hectorite, saponite, beidelite, nontronite, mica, vermiculite, carnemite, margadite, Kenyaite, kaolinite, smectite, illite, chlorite, muscobite, Pyrophyllite, antigolite, sepiolite, imogolite, sobokite, nacrite, anoxite, sericite, and phenolic foam resin composition comprising at least one member selected from the group consisting of redite. According to claim 1,
The phenolic resin,
500 to 2,000 weight average molecular weight (Mw) in g/mol; and
Having a moisture content of 3 to 15%, a phenolic foam resin composition. According to claim 1,
The phenolic resin,
It includes polymers of phenol and aldehyde-based compounds,
The molar ratio of the phenol and the aldehyde-based compound is 1: 1.2 to 3.6, the phenol foam resin composition. According to claim 1,
The foaming agent containing at least one selected from the group consisting of hydrocarbon-based foaming agents and halogenated hydrocarbon-based foaming agents, phenol foam resin composition. According to claim 1,
The curing agent is an acid curing agent, a phenol foam resin composition. According to claim 1,
Further comprising at least one selected from the group consisting of a plasticizer, a surfactant and a flame retardant, the phenol foam resin composition. A phenol foam in which the phenol foam resin composition according to any one of claims 1 to 9 is foamed and cured. According to claim 10,
A phenolic foam having a residual formaldehyde content of less than 50 mg/kg. According to claim 10,
A phenolic foam that satisfies at least one or more physical properties of the following conditions (i) to (ix):
(i) a limiting oxygen index (LOI) greater than or equal to 40%;
(ii) the total heat release is less than 8.0 MJ/m2 (based on 10 minutes),
(iii) a thermal conductivity of 0.015 to 0.022 W/m K;
(iv) a compressive strength of 40 to 250 kpa;
(v) a flexural breaking load of 15 to 40 N;
(vi) a water absorption rate of 1.0 to 10.0%;
(vii) a water vapor permeability of 3.0 to 20.0 ng/m s Pa;
(viii) a density of 30 to 50 kg/m 3 ,
(ix) The closed cell rate is 60 to 99%. An insulating material comprising the phenolic foam of claim 10.