KR20180120383A - Fire retardant polyurethane foam and method for fabricating the same, polyurethane board and sandwich panel using the same - Google Patents

Abstract

Fire retardant polyurethane foam according to the present invention contains 5 to 38 wt% of sodium hydrogen carbonate as a flame retardant, 5 to 30 wt% of expanded graphite, and 5 to 38 wt% of borax based on the total weight. The fire retardant polyurethane foam may further include hydrotalcite, calcium carbonate (CaCO_3), or silicate as other flame retardants. According to the present invention, succulent digestion is carried out by sodium hydrogen carbonate at a relatively low temperature at the beginning of the fire. Also, the use of borax allows not only the fire extinguishment using crystal water even at a temperature higher than the contribution temperature of the expanded graphite, but also the borax serves as a binder so that the shape of the expanded graphite is maintained at a higher temperature than the conventional cases. Therefore, through the organic functions per temperature ranges of the sodium hydrogen carbonate, expanded graphite, and borax, the fire retardant polyurethane foam exhibits excellent flame retardancy from early stage of fire to high temperatures.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a fire retardant polyurethane foam, a polyurethane foam board and a sandwich panel using the fire retardant polyurethane foam,

The present invention relates to a flame-retardant foamed polyurethane, and more particularly to a flame-retardant foamed polyurethane foam which uses nitrogen hydrogencarbonate as a flame retardant so as to cause vigorous extinguishment from the beginning of the fire and furthermore the use of borax in combination with expanded graphite as a flame- To a high temperature, and to a flame-retardant foamed polyurethane.

The present invention also relates to a polyurethane fireproof board and a sandwich panel using the flame-retardant foamed polyurethane.

Polyurethane is often used in construction materials in the form of heat insulation boards or adhesives.

FIG. 1 is a view for explaining a general sandwich panel 10. FIG. 1, the sandwich panel 10 has a structure in which a core member 12, which is a heat insulator, is interposed between two steel plates 11, and the core member 12 is bonded to the steel plate 11 by an adhesive 13, As shown in Fig. Foamed urethane, styrofoam, glass wool (fiberglass), mineral wool and the like are used as the core material 12, and a polyurethane adhesive is widely used as the adhesive 13.

When the foamed urethane or styrofoam is used as the core material (12), the panel is advantageous in that it is light in weight and inexpensive. However, it is difficult to evolve the fire due to the flame spreading due to the flame- Carbonization phenomenon occurs and toxic gas is generated.

Glass wool (glass fiber) refers to glass formed by melting glass. When such glass wool is used as core material (12), fire resistance is superior to that of foamed urethane or styrofoam. However, It is harmful and expensive.

When mineral wool is used as core material (12), it is inexpensive and has fire resistance performance as compared with the case of using glass wool. However, it is heavy, There is a drawback to doing so.

There have been many attempts to impart flame retardancy to core (12) when using foamed urethane or styrofoam, which has poor flame retardant effect as core material (12).

Korean Patent Publication No. 10-2009-0019407 (published on February 25, 2009) is an example thereof. However, as the flame retardancy of the core material 12 is secured, the fragile flame retardancy of the polyurethane adhesive 13 as a counterproductive factor becomes a bigger problem. Therefore, in order to impart flame retardancy to the polyurethane adhesive 13, .

Korean Patent No. 1494801 (published on Feb. 23, 2015) and Korean Patent No. 1538719 (issued on Feb. 28, 2015) disclose a technique for improving the fire resistance by adding carna- tus of sugar phosphate together with expanded graphite in the production of a polyurethane adhesive .

The expanded graphite expands when a fire occurs and forms a heat insulating layer to prevent the diffusion of fire. In such an expansion, the graphite easily splashes due to its low specific gravity and binding force, which disadvantageously fails to form a continuous heat insulating layer. Accordingly, the above-mentioned patents are characterized by preventing the shape collapse of expanded graphite by using carbohydrate of sugar, caramel.

However, caramelized sugar caramel is a kind of organic compound, which is carbonized at low temperature. Therefore, it does not overcome the fact that a fire occurs and the original function of maintaining the shape of expanded graphite can not be performed when the temperature rises to some extent.

 On the other hand, in Korean Patent No. 1513560 (published on Apr. 21, 2015), when the expanded graphite or the like is added to the polyurethane adhesive as the flame retardant, the adhesion performance of the flame retardant component is lowered, thereby improving the overall adhesion of the polyurethane adhesive A method of adding an organic binder is disclosed. However, in this case, since the binder is an organic compound series, it is difficult to expect the improvement of the flame retarding effect due to the disadvantage that it is carbonized at a low temperature.

On the other hand, expandable graphite is composed of nitric acid or sulfuric acid treated water for expanding force of about 20% of the total weight. When nitric acid or sulfuric acid-treated material is contained between the layers, The heat insulating layer is expanded while expanding explosively between the layer and the layer. At this time, since the expansion starting temperature is usually about 150 to 500 ° C, it has a disadvantage in that it can not function in the initial stage of fire at a temperature lower than that.

Korean Registered Patent No. 1494801 (Announced Feb. 23, 2015) Korean Registered Patent No. 1538719 (Announced on July 28, 2015) Korean Registered Patent No. 1513560 (Bulletin of April 21, 2015)

Therefore, a problem to be solved by the present invention is to provide a flame retardant agent which is optimized for fire evolution according to temperature bands when a fire occurs, but can contribute to suppression from the beginning of the fire by using an inorganic compound that is not an organic compound for maintaining the shape of expanded graphite The present invention also provides a flame-retardant foamed polyurethane which is excellent in high-temperature flame-retardant effect by maintaining the shape of expanded graphite even at a temperature higher than the conventional one, and a method for producing the same.

Another object of the present invention is to provide a polyurethane fireproof board and a sandwich fireproof panel using the flame retardant foamed polyurethane.

In order to achieve the above object, the flame-retarded foamed polyurethane according to the present invention is characterized by comprising sodium hydrogen carbonate as a flame retardant. At this time, it is preferable that expanded graphite and borax are further included as the flame retardant. The flame retardant may further include hydrotalcite, calcium carbonate (CaCO ₃ ), or silicate.

The sodium hydrogencarbonate is preferably 5 to 38% by weight, the expanded graphite is 5 to 30% by weight, and the borax is 5 to 38% by weight based on the total weight of the flame-retardant foamed urethane.

The flame-retarded foamed urethane according to the present invention may contain expanded graphite and borax as flame retardants.

According to the present invention, there is provided a method for producing a flame-

Mixing and stirring sodium hydrogen carbonate, expanded graphite, and borax in one of the solution A containing the polyol and the solution B containing the isocyanate; And

Subjecting the solution A and the solution B to a foaming reaction; And a control unit.

It is preferable that 5 to 38% by weight of the sodium hydrogen carbonate, 5 to 30% by weight of the expanded graphite and 5 to 38% of the borax are contained in the solution A and the solution B, based on the total weight of the solids.

In order to achieve the above object, a polyurethane fireproof board according to the present invention is characterized in that a polyurethane board is interposed between an upper substrate and a lower substrate, wherein the polyurethane board is made of the flame retarded foamed polyurethane.

According to another aspect of the present invention, there is provided a sandwich fire-retardant panel comprising a core material as a heat insulating material between an upper substrate and a lower substrate, wherein the flame retardant foamed polyurethane is sandwiched between the core material and the upper substrate, As shown in Fig.

According to the present invention, succulent digestion is carried out by sodium hydrogencarbonate at a relatively low temperature at the beginning of the fire. The use of borax not only extinguishes the crystal water even at a temperature higher than the contribution temperature of the expanded graphite, but also serves as a binder, and the shape of the expanded graphite is maintained to a higher temperature than the conventional one. Therefore, through the functions of organic temperature range of sodium bicarbonate, expanded graphite, and borax, excellent flame retardancy is exhibited from the early stage of fire to high temperature.

1 is a view for explaining a general sandwich panel 10;
2 is a view for explaining a urethane fireproof board 100 according to the present invention and a method of manufacturing the same.
3 is a view for explaining a sandwich fireproof panel 200 according to the present invention and a method of manufacturing the same.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are merely provided to understand the contents of the present invention, and those skilled in the art will be able to make many modifications within the technical scope of the present invention. Therefore, the scope of the present invention should not be construed as being limited to these embodiments.

[Components and Content of Flame Retardant Foamed Urethane]

The flame-retarded foamed urethane according to the present invention comprises 5 to 38% by weight of sodium hydrogencarbonate, 5 to 30% by weight of expanded graphite, 5 to 38% by weight of borax and 11 to 42% by weight of other inorganic compounds, based on the total weight. The flame-retardant foamed polyurethane according to the present invention can be used as an adhesive and can also be used as an insulation material.

1. Polyol, isocyanate

The flame-retarded foamed urethane according to the present invention is obtained through the reaction of solution A containing a free alcohol and solution B containing isocyanate. In this case, it is particularly characterized in that the above-mentioned sodium hydrogencarbonate, expanded graphite, borax, and other inorganic compounds are contained in either solution A or solution B.

2. Sodium bicarbonate

When sodium bicarbonate (NaHCO ₃ ) is heated, carbon dioxide (CO ₂ ) and water (H ₂ O) are generated which are useful for the evolution of fire. This reaction occurs at a temperature of 100-200 ° C. It is possible to prevent fire transition from immediately after. In addition, since the above reaction occurs even if it acts with an acid such as sulfuric acid or nitric acid contained in the layer of the expanded graphite, it also works with expansion graphite and contributes to the digestion.

3. Expansive graphite

Expanded graphite is composed of nitric acid or sulfuric acid treated water for expanding force of about 20% of total weight. When nitric acid or sulfuric acid treated material is contained between layers, it is burned when the fire occurs. The layer between the layer and the layer expands explosively to form a heat insulating layer to block the spread of the fire.

In the early stage after 5-10 minutes of fire, the temperature rises to 500 ~ 600 ℃. In this early stage, many organic materials are pyrolyzed to generate combustible gas, which causes the fire to expand. Therefore, flame retardant performance at 500 ~ 600 ℃, which is the initial stage of fire, is important. At this time, since the expansion starting temperature of the above-mentioned expanded graphite is about 150 to 300 캜, the expanded graphite plays a large role in the initial suppression of the fire.

4. Borax

Expanded graphite is easily scattered due to low specific gravity and binding at the time of expansion, so that a continuous heat insulating layer can not be formed. As an anti-scattering agent for preventing scattering of expanded graphite, when an organic compound such as caramelized sugar caramel is used as in the prior art, when the temperature rises to some extent due to a fire, the organic compound is carbonized and the shape of the expanded graphite can not be properly prevented.

In the present invention, borax (Borax, sodium tetraborate decahydrate, NaB ₄ O ₇ .10H ₂ O), an inorganic compound, is used as a scattering inhibitor of expanded graphite to solve this problem.

Borax crystals contain 10 molecules of water. When heated to 300-450 ℃, the borax crystal loses crystals and expands to become an anhydrous. When it is continuously heated, it melts at 900 ° C to form a transparent glass phase. Therefore, not only is it extinguished by crystallization water at a temperature of 300 to 450 ° C higher than the contribution temperature of expanded graphite, but also plays a role as a binder for maintaining the shape of expanded graphite at almost 900 ° C.

5. Other inorganic compounds

The flame-retarded foamed polyurethane according to the present invention may further contain hydrotalcite, calcium carbonate (CaCO ₃ ), silicate and the like as other inorganic compounds.

Hydrotalcite is a kind of hydroxide. The octahedral unit having a divalent or trivalent metal cation positioned at the center and six hydroxide ions (OH ^- ) surrounding the metal cation is used as a basic unit. It has a double layer structure to form a layer, and anion and water molecules are positioned between the two layers, and the balance is maintained. Is generally expressed by a general formula of [M ^Ⅱ _1-X M ^Ⅲ _x (OH) ₂ (A ^n- ) _{2 / n} ㅇ mH ₂ O]. Where M ^Ⅱ is a divalent metal, M ^Ⅲ is a trivalent metal, and A ^n- is an anion having a valence of n.

Hydrotalcite contains water molecules adsorbed on the surface in addition to water molecules (crystal water) between the two layers. When heat is applied to the hydrotalcite, water molecules adsorbed on the surface are first removed, and more When heated to a high temperature, water molecules (crystalline water) between the two layers are removed. Thus, the water is prevented from spreading fire.

 Calcium carbonate not only generates carbon dioxide that is useful for digestion upon heating but also generates carbon dioxide by reacting with acids such as nitric acid and sulfuric acid contained in expanded graphite.

Silicate means a neutral salt in which hydrogen of various silicic acids is substituted with a metal atom and is represented by the general formula xM ^I ₂ O ySiO ₂ (M is a monovalent metal). It has fire resistance by itself and forms a glass phase when heated to contribute to the maintenance of the shape of the expanded graphite.

As described above, according to the present invention, succulent digestion is carried out by sodium hydrogencarbonate from a relatively low temperature at the beginning of the fire. The use of borax not only extinguishes the crystal water even at a temperature higher than the contribution temperature of the expanded graphite, but also serves as a binder, and the shape of the expanded graphite is maintained to a higher temperature than the conventional one. Therefore, through the functions of organic temperature range of sodium bicarbonate, expanded graphite, and borax, excellent flame retardancy is exhibited from the early stage of fire to high temperature.

[Production of urethane fireproof board 100]

2 is a view for explaining a urethane fireproof board 100 according to the present invention and a method of manufacturing the same.

As shown in Fig. 2A, first, a solution A containing polyol and a solution B containing isocyanate are prepared. At this time, any one of the solution A and the solution B contains sodium hydrogen carbonate, expanded graphite, and borax mixed and stirred. Sodium hydrogen carbonate, expanded graphite, and borax are contained so as to occupy 5 to 38 wt%, 5 to 30 wt%, and 5 to 38 wt%, respectively, with respect to the total solid content of Solution A and Solution B, The solids content of the solution A and the solution B is about 35 to 45% by weight based on the total weight of the solution A and the solution B.

Next, the solution A and the solution B are injected into the space between the upper substrate 111 and the lower substrate 112 through the mixing nozzle 140. The solution A and the solution B are mixed in the mixing nozzle 140 and injected outside. Then, a foaming reaction occurs between the upper and lower base materials 111 and 112, and a flame-retardant foamed urethane 130 is formed. The roller 150 is for allowing the upper substrate 111 and the lower substrate 112 to move while maintaining a gap therebetween.

The flame-retardant foamed urethane 130 is strongly adhered to the upper and lower substrates 111 and 112 as well as the flame-retardant foamed urethane 130 itself because of the expansion force caused by the foaming reaction. Therefore, The upper and lower base materials 111 and 112 are naturally adhered to the flame-retardant foamed urethane 130 even if there is no special adhesive between them.

The urethane fireproof board 100 having the upper substrate 111 and the lower substrate 112 adhered to the bottom surface of the flame retardant foamed urethane 130 as shown in FIG. 2B is obtained by continuing this operation while rotating the roller 150 . The upper substrate 111 and the lower substrate 112 may be made of various materials such as paper or glass fiber.

[Manufacture of Sandwich Fireproof Panel (200)] [

3 is a view for explaining a sandwich fireproof panel 200 according to the present invention and a method of manufacturing the same.

As shown in FIG. 3A, a core 220 is disposed between the upper substrate 211 and the lower substrate 212. The solution A and the solution B are mixed and injected into the space between the core member 220 and the upper substrate 211 and the space between the core member 220 and the lower substrate 212 through the mixing nozzle 240.

 Flame retardant foamed urethane 230 is formed on the upper and lower surfaces of the core member 220. The flame retardant foamed urethane 230 is strongly adhered to the core member 220 and the upper and lower substrates 211 and 212 by the expansion force due to the foaming reaction . Since the flame-retardant foamed urethane 230 itself has tackiness, the flame-retardant foamed urethane 230 acts as an adhesive, so that the core material 220 and the upper and lower substrates 211 and 212 are bonded to each other.

Therefore, if the above operation is continued while the roller 250 is rotated, the sandwich fireproof panel 200 having the core member 220 interposed between the upper and lower substrates 211 and 212 is obtained as shown in FIG. 3B.

As the upper and lower base materials 211 and 212, a steel sheet may be used, and as the core material 220, various materials such as expanded polystyrene (EPS) and foamed polyurethane may be selected. The core member 220 is attached to the upper and lower substrates 211 and 212 by an adhesive composed of a flame retardant foamed urethane 230.

100: Urethane refractory board 140: Mixing nozzle
111, 211: upper substrate 112, 212: lower substrate
130, 230: flame retardant foam urethane 150, 250: roller
200: Sandwich fireproof panel 220: Core material

Claims (10)

A flame-retarded foamed polyurethane characterized by comprising sodium hydrogen carbonate as a flame retardant. The flame-retarded foamed polyurethane according to claim 1, further comprising expanded graphite and borax as said flame retardant. The flame-retarded foamed polyurethane according to claim 2, wherein the flame retardant further comprises hydrotalcite, calcium carbonate (CaCO ₃ ), or silicate. A flame retarded foamed polyurethane characterized by comprising expanded graphite and borax as flame retardants. The flame-retarded foamed polyurethane according to claim 4, wherein the flame retardant further comprises hydrotalcite, calcium carbonate (CaCO ₃ ), or silicate. [5] The method according to claim 2, wherein 5 to 38% by weight of the sodium hydrogencarbonate, 5 to 30% by weight of the expanded graphite and 5 to 38% by weight of the borax are contained in the total weight of the flame- Flame retardant foamed polyurethane. Mixing and stirring sodium hydrogen carbonate, expanded graphite, and borax in one of the solution A containing the polyol and the solution B containing the isocyanate; And
Subjecting the solution A and the solution B to a foaming reaction; Wherein the flame retardant is a polyurethane foam. The method according to claim 7, wherein 5 to 38% by weight of the sodium hydrogencarbonate, 5 to 30% by weight of the expanded graphite and 5 to 38% by weight of the borax are contained in the solution A and the solution B, Wherein said polyurethane foam is a polyurethane foam. A polyurethane fireproof board characterized in that a polyurethane board is interposed between an upper substrate and a lower substrate, wherein the polyurethane board is made of a flame-retardant foamed polyurethane according to any one of claims 1 to 6. A flame retarded foamed polyurethane according to any one of claims 1 to 6 is interposed as an adhesive between the core material and the upper substrate and between the core material and the lower substrate with a core material as a heat insulating material between the upper substrate and the lower substrate Wherein the sandwich fireproof panel is made of steel.

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