Fireproof panels and methods of fabricating the same

Methods and apparatus are provided for making a fireproof panel. The fireproof panel includes a first ply of material and a ceramic material impregnating at least a portion of the first ply of material, the ceramic material formulated to resist loss of physical properties when exposed to temperatures of at least 1090° C.

TECHNICAL FIELD

The inventive subject matter generally relates to fireproof panels, and more particularly relates to single and multi-ply fireproof panels and methods of fabricating materials for the panels.

BACKGROUND

Many types of materials are used in the manufacturing of aircraft. Depending on the purpose for which the materials may be used, the materials may be subjected to certain standards set by the Federal Aviation Administration (FAA) and/or other governmental regulation agencies. For example, fire-resistant materials and structures may be implemented into aircraft to improve aircraft safety; however, before these materials or structures are used, they are investigated to determine whether they pass certain regulatory fire-resistance tests. One such test is delineated in Advisory Circular 20-135, which indicates that materials and structures used for fire-resistance purposes should be capable of withstanding a 2000° F. (1090° C.) flame for fifteen minutes. A structure which passes this test is designated as “fireproof”.

Polymeric composite materials, such as bismaleimide (BMI), have been used in the past to form structures that meet the aforementioned FAA fireproof tests. However, although these materials provide adequate fire-resistant properties, they have certain drawbacks. In particular, BMI may be relatively expensive to obtain, and thus, inclusion thereof may increase aircraft manufacturing costs. Moreover, BMI materials may be export-controlled. As a result, the locations at which aircraft components including BMI materials can be manufactured may be limited and manufacturing costs may be high.

Accordingly, it is desirable to have improved materials and/or structures that at least pass tests regarding fireproof capability and that are not export-controlled. In addition, it is desirable to have materials and/or structures that are relatively simple to implement into existing aircraft component designs. Moreover, it is desirable to have processes to fabricate the materials and/or structures that are relatively inexpensive as well. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.

BRIEF SUMMARY

Fireproof panels and methods of fabricating fireproof panels are provided.

In an embodiment, by way of example only, a fireproof panel includes a first ply of material and a ceramic material impregnating at least a portion of the first ply of material, where the ceramic material is formulated to resist loss of mechanical properties when exposed to temperatures of at least 1090° C.

In another embodiment, by way of example only, a multi-ply fireproof panel includes a first outer ply of material, a second outer ply of material, and one or more inner plies of material. The first outer ply includes a ceramic material impregnated therein, where the ceramic material is formulated to resist loss of mechanical properties when exposed to temperatures of about 1090° C. The second outer ply of material includes the ceramic material impregnated therein. The one or more inner plies of material are impregnated with a matrix resin and disposed between the first outer ply of material and the second outer ply of material.

In yet another embodiment, by way of example only, a method of fabricating a fireproof panel includes impregnating at least a portion of a first ply of material with a ceramic material, the ceramic material comprising one or more compounds including a material selected from the group consisting of sodium silicate, sodium oxide, silica, alumina, silicon carbide, zirconium oxide, boron nitride, titanium nitride, magnesia, and yttria, and heat treating the impregnated first ply of material to form the fireproof panel.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the inventive subject matter or the application and uses of the inventive subject matter. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

FIG. 1is a cross-sectional side view of a fireproof panel100, according to an embodiment. The fireproof panel100may be implemented into any one of numerous applications in which isolation from a fire of a space or a device may be desired. In accordance with one embodiment, the fireproof panel100may be incorporated into an aircraft, a wall of a building, or another enclosed area to isolate two fire zones from each other or to isolate a fire zone and a non-fire zone from each other. In another embodiment, the fireproof panel100may be used as a stand-alone device, such as a shield, to isolate a user, vehicle or another device from direct contact with a flame. According to an embodiment, the fireproof panel100is configured to withstand a burn test in which the panel100is placed adjacent to a flame having a temperature of about 2000° F. (1090° C.). In one embodiment, the fireproof panel100is adapted to withstand the 2000° F. (1090° C.) flame for 15 minutes without the flame burning through one side of the panel100to an opposite side thereof or igniting material on the opposite side. A panel which withstands such conditions is designated as “fireproof” in Department of Transportation Advisory Circular 20-135. In yet other embodiments, the fireproof panel100may be capable of withstanding the 2000° F. (1090° C.) flame for more than 15 minutes.

In one embodiment, the fireproof panel100may include a single ply of material102and a ceramic material104. The single ply of material102may include a ply of fibers. In accordance with an embodiment, the ply of fibers may be a unidirectional flat array of fibers. According to another embodiment, the ply of fibers may be fibers which are braided or woven, such as in a plain weave or five harness weave, to form a fabric.FIG. 1specifically illustrates a five harness weave in which a longitudinal fiber105is woven over and under a group of four transverse fibers103shown as a single entity. The ply of material102may have a thickness in a range of about 0.10 mm (e.g., for aligned fibers) to about 0.9 mm (e.g., for a braided or woven fabric). In an embodiment with a five harness weave, the thickness of the ply of material102is about 0.4 mm. In any case, the ply of material may include fibers or fabrics of a material selected from the group consisting of carbon fiber, silica-alumina fiber, ceramic fiber, and basalt fiber. Examples of suitable carbon fabrics include, but are not limited to fabrics woven from carbon fiber, such as Panex® material available through Zoltek Corporation of Missouri, T300 6K five harness weave fabrics available through Toray Industries Inc. of Japan, and the like. Suitable silica-alumina fiber materials include, but are not limited to Silcosoft® needled felt materials available through BGF Industries of Greensboro, N.C. Basalt fabrics that may be suitable for inclusion in the fireproof panel100include, but are not limited Basaltex® materials available through Groep Masureel of Belgium. In other embodiments, other types of fiber or fabric materials may alternatively be employed.

The ceramic material104is impregnated into at least a portion of the ply of material102. In an embodiment, the ceramic material104is impregnated into at least a portion of an interior of the ply of material102proximate a surface, thereof, in an embodiment. In another embodiment, the ceramic material104impregnates substantially the entire ply of material102so that the ceramic material104is disposed on the surface, on an opposite surface, and in spaces between the fibers and/or fabric of the ply of material102.

According to an embodiment, the ceramic material104is formulated to substantially resist decomposition when exposed to temperatures of about 1090° C. or higher. As used herein, the term “decomposition” may be defined as a loss of physical properties, where the physical properties may include loss of structural integrity, which may result from melting. To substantially resist decomposition, the ceramic material104may include one or more compounds that may be selected for certain physical properties, such as adhesion to carbon fibers, good mechanical properties at temperatures exceeding 1090° C., and solubility in water. In one embodiment, the ceramic material104may be formulated to include a compound that includes sodium silicates. Examples of suitable sodium silicate compounds include, but are not limited to, sodium orthosilicate (e.g., Na4SiO4or 2Na2O.SiO2), sodium metasilicate (e.g., Na2SiO3or Na2O.SiO2), sodium disilicate (e.g., Na2Si2O5or Na2O.2SiO2), and sodium tetrasilicate (e.g., Na2Si4O9or Na2O.4SiO2). In another embodiment, the ceramic material may be formulated as a mixture of two or more sodium silicate compounds.

In still yet another embodiment, the ceramic material104may comprise a compound that includes alumina. According to another embodiment, the ceramic material104may comprise a compound that includes silicon carbide. In accordance with another embodiment, the ceramic material104may comprise a compound that includes zirconium oxide. According to yet another embodiment, the ceramic material104may comprise a compound that includes a nitride, including but not limited to boron nitride and titanium nitride. In still another embodiment, the ceramic material104may comprise a compound that may include magnesia or that may include yttria. In any case, by impregnating at least a portion of the ply of material102with the ceramic material104, the material becomes stiffer and adjacent fibers bond to form a more rigid structure. As a result, the impregnated ply of material102may be more resistant to fires and/or may be more capable of containing fires having temperatures of at least 2000° F. (1090° C.) as compared to untreated fibers, untreated fabrics or untreated materials.

In another embodiment, the ply of material may be incorporated into a multi-ply panel.FIG. 2is a simplified, cross-sectional view of a fireproof panel200, according to an embodiment, that includes multiple plies of material. The multi-ply fireproof panel200includes an outer ply of material202, one or more inner plies of material204, and a matrix resin206. According to an embodiment, the outer ply202has an exposed surface208that is adapted to be exposed to a flame and has an unexposed surface210that may be bonded to an adjacent inner ply204. To provide fire-resistance, the outer ply202is constructed substantially similarly to the ply of material102(FIG. 1) discussed above. For example, the outer ply202may include a ply of material214made up of fibers or fabric, and the ply of material214may be at least partially impregnated with a ceramic material216. The ply of material214is selected from one of the above-mentioned fiber or fabrics. In one embodiment, as shown inFIG. 2, the ply of material214includes fibers woven over and under each other to form a fabric. The ceramic material216is selected from one of the above-mentioned ceramic materials. The ceramic material216may be disposed on at least a portion of the exposed surface208of the outer ply202, in an embodiment. In another embodiment, the ceramic material216may impregnate an entirety of the outer ply202and is thus disposed at least partially on the exposed and unexposed surfaces208,210of the outer ply202. The outer ply202may have a thickness in a range of from about 0.1 mm to about 0.9 mm.

The inner ply204is adhered to the outer ply202and provides additional structural rigidity for the multi-ply fireproof panel200. In an embodiment, the inner ply204may include a fiber or fabric material215. In one embodiment, as shown inFIG. 2, fiber or fabric material215includes fibers woven over and under each other to form a fabric. The fiber or fabric material214may be selected from carbon fiber, silica-alumina fiber, ceramic fiber, and basalt fiber. Examples of suitable carbon fiber or fabric include, but are not limited to fabrics woven from carbon fiber such as Panex® materials available through Zoltek Corporation of Missouri, T300 6K five harness weave fabrics available through Toray Industries Inc. of Japan, and the like. Suitable silica-alumina fiber or fabrics include, but are not limited to Silcosoft® needled felt materials available through BGF Industries of Greensboro, N.C. Basalt fiber or fabrics that may be suitable for inclusion in the fireproof panel200include, but are not limited Basaltex® materials available through Groep Masureel of Belgium. In other embodiments, other types of fiber or fabric materials may alternatively be employed.

The fiber or fabric material215of the inner ply204may be the same fiber or fabric material as that used in the outer ply202, in an embodiment. In another embodiment, the fiber or fabric material215of the inner ply204may be different from the ply of material214of the outer ply202. For example, the fiber or fabric material215of the inner ply204may include a first type of carbon fiber or fabric, such as one provided by carbon fiber woven fabrics such as Panex® materials available through Zoltek Corporation of Missouri, while the outer ply fiber or fabric material214may include a second type of carbon fiber fabric, such as a T300 6K five harness weave fabric available through Toray Industries Inc. of Japan.

The matrix resin206impregnates and adheres the fiber or fabric215of the inner ply204to the fiber or fabric214of the outer ply202and thus, in an embodiment, may be present in the outer ply202as well as the inner ply204. Examples of materials suitable for the matrix resin206include an epoxy matrix compound that includes a phenol novolac resin, a polyether elastomer as a toughening agent, and an ammonium phosphate salt as a flame retardant. A hardener may be mixed with the epoxy matrix compound to initiate a cure process. The hardener may be comprised of diaminodiphenylsulfone (DDS) and a hindered alkyl aromatic amine. An alternative matrix resin206can be compounded based on benzoxazine chemistry.

Although the inner ply204is shown as a single layer, it will be appreciated that the inner ply204may include more than one layer.FIG. 3is a close-up, cross-sectional view of a fireproof panel300similar to fireproof panel200depicted inFIG. 2, except fireproof panel300includes a multiple inner plies304, according to an embodiment. These inner plies304consist of two layers306,308of fiber or fabric materials, in an embodiment, and in other embodiment may include more layers. In one embodiment, as shown inFIG. 3, the layers306,308each include fibers woven over and under each other to form a fabric. The layers306,308may be formed from a single type of fiber or fabric material, in an embodiment. However, in other embodiments, each layer may be different types of fiber or fabric materials. A matrix resin310and314formulated similar to matrix resin206ofFIG. 2may partially impregnate and adhere the fiber or fabric of a first outer ply302and an adjacent inner ply layer308of fiber or fabric. Inner ply layers308of fiber or fabric adhere to adjacent inner ply layers306of fiber or fabric by means of matrix resin312impregnated into fiber or fabric layer306and matrix resin310impregnated into fiber or fabric layer308. Additional inner ply layers may be added in a manner similar to that described previously. It will be appreciated that matrix resin310312, and314may be indistinguishable from each other, in some embodiments, and each may be present in adjacent plies.

To provide the fireproof panel300with additional fire-resistant properties, a second outer ply may be included, in an embodiment.FIG. 4is a close-up, cross-sectional view of a fireproof panel400similar to fireproof panel200depicted inFIG. 2and to fireproof panel300depicted inFIG. 3, except fireproof panel400includes a second outer ply414, according to an embodiment. In an example, a first outer ply402and the second outer ply414are disposed such that an inner ply404is located therebetween. Matrix resin408,410, and412impregnate and adhere the first outer ply402to a first side of the inner ply404and the second outer ply414to a second side of the inner ply404. It will be appreciated that inner ply404may include a single layer, such as in panel200, or inner ply404may be replicated into multiple layers, such as in panel300.

In any case, the second outer ply414is configured similarly to outer ply202(FIG. 2) and to outer ply302(FIG. 3). In this regard, the second outer ply414includes at least a portion of ply of material420, which may be fibers or a fabric, impregnated with a ceramic material416that is at least disposed on an adjacent exposed surface418thereof, where the ply of material420is selected from one of the above-mentioned fiber or fabrics. In one embodiment, as shown inFIG. 4, the ply of material420includes fibers woven over and under each other to form a fabric. The ceramic material416is selected from one of the above-mentioned ceramic materials. The ceramic material416impregnates at least a portion of an interior of the ply of material420adjacent the exposed surface418in an embodiment. In another embodiment, the ceramic material416may impregnate an entirety of the second outer ply414and may be disposed on at least a portion of the exposed and unexposed surfaces418,422of the second outer ply414. The second outer ply414may have a thickness in a range of between about 0.1 mm to about 0.9 mm. In other embodiments, the thickness of the second outer ply414may be thicker or thinner than the aforementioned range. In an embodiment, the second outer ply414may be configured substantially similarly to the first outer ply402. In another embodiment, the second outer ply414may be made of different materials than the first outer ply402. Alternatively, as shown in the first outer layer402, the region impregnated with the ceramic material416can extend to an outer surface428of the outer layer402. In another embodiment, additional matrix resin426may be applied to the outer surface418of the second outer ply414.

FIG. 5is a flow diagram of a method400for fabricating fire-resistant materials, according to an embodiment. The method400may be used to manufacture panels as well (e.g., panel100ofFIG. 1, panel200ofFIG. 2, panel300ofFIG. 3, and panel400of FIG.4). In accordance with one embodiment, ceramic materials, fiber or fabric materials, and matrix resin materials are selected, step502. The ceramic materials, fiber or fabric materials, and matrix resin materials may include those mentioned above to describe panel100ofFIG. 1, panel200ofFIG. 2, panel300ofFIG. 3, and panel400ofFIG. 4. For example, the ceramic material may be formulated to include a compound that includes compounds formed from sodium oxide (Na2O), silica (SiO2) or from sodium silicate compounds. Examples of suitable sodium silicate compounds include, but are not limited to, sodium orthosilicate (e.g., Na4SiO4or 2Na2O.SiO2), sodium metasilicate (e.g., Na2SiO3or Na2O.SiO2), sodium disilicate (e.g., Na2Si2O5or Na2O.2SiO2), and sodium tetrasilicate (e.g., Na2Si4O9or Na2O.4SiO2). In yet another embodiment, the ceramic materials may be formulated to include one or more sodium silicate compounds). In still yet another embodiment, the ceramic material may comprise a compound that includes alumina. According to another embodiment, the ceramic material may comprise a compound that includes silicon carbide. In accordance with another embodiment, the ceramic material may comprise a compound that includes zirconium oxide. According to yet another embodiment, the ceramic material may comprise a compound that includes a nitride, including but not limited to boron nitride and titanium nitride. In still another embodiment, the ceramic material may comprise a compound that may include magnesia or that may include yttria. In another example, the material comprises a fiber or fabric selected from the group consisting of a carbon fiber or fabric, a silica-alumina fiber or fabric, a ceramic fiber or fabric, and a basalt fiber or fabric.

According to an embodiment of method500, a first ply of material is then impregnated with the ceramic material, step504. In an embodiment, step504includes placing the ceramic material into solution. A particular formulation of the solution may depend on the particular ceramic material selected and on the viscosity of the solution. Appropriate diluents may be added to reduce the viscosity of the solution. In one example, in which the ceramic material includes a compound with one or more sodium silicates, the viscosity of the solution may be reduced by adding water.

In still yet another embodiment in which the ceramic material may comprise a compound that includes alumina, the ceramic material may further include an aluminum hydroxide oxide solution. According to another embodiment where the ceramic material may comprise a compound that includes silicon carbide, the solution may further include a phosphoric acid aqueous solvent. In accordance with another embodiment, the ceramic material may comprise a compound that includes zirconium oxide in a sodium metasilicate solution. According to yet another embodiment the ceramic material may comprise a compound that includes boron nitride, the boron nitride may be in an organic solvent, such as alcohol acetone. In another embodiment in which the ceramic material includes titanium nitride, the titanium nitride may be in an alcohol/acetone solvent. In still another embodiment, the ceramic material may comprise a compound that may include yttria which may be in an alcohol acetone solution.

In any case, the solution including the ceramic material may be painted onto the first ply of material, and allowed to soak into the first ply. For example, a brush may be dipped into the solution including the ceramic material therein to apply the ceramic material to impregnate at least a portion of the first ply of material therewith. Alternatively, the solution may be applied with a roller or may be sprayed on only one surface of the material or on both surfaces of the material. In another embodiment, the first ply of material is dipped into the solution including the ceramic material. The first ply of material is then removed from the solution, and excess solution is dripped off.

The first ply of material is then air dried and heat treated, step506. In an embodiment, the first ply of material is air-dried so that at least a portion of the liquid from the ceramic material solution evaporates. Air-drying may occur for between about 2 hours and about 16 hours. In addition, or alternatively, the first ply of material may be heated to remove the liquid therefrom. According to an embodiment, step506may occur in an oven. The first ply of material may be unconstrained, or alternatively may be secured between two screens for drying to prevent deformation. In accordance with another embodiment, the first ply of material may be placed in a mold, and step506may occur therein. In accordance with an embodiment, the first ply of material is heated to a temperature in a range of between about 110° C. to about 130° C., for at least one hour to remove substantially all (e.g., at least 99%) of the water. If the first ply is exposed to ceramic solution only on one side, the matrix material may be applied to the opposite side of the first ply in the form of a paste, powder or film.

According to another embodiment, if the dried first ply of material is to be used to form a multi-ply fireproof panel, it may be used with additional resin-impregnated and ceramic-treated fabrics, step508. In one embodiment, the first ply of material is adhered to a second ply of material. A matrix resin may be applied to one or both of the first and/or second plies of material. In an embodiment, the matrix resin may be an epoxy that is applied to a surface of the first ply that is not exposed to the ceramic material. According to another embodiment, one or both surfaces of the second ply of material may include the matrix resin thereon. The matrix resin may be applied by dusting a powder, painting, or pouring and distributed by a blade or squeegee. Alternatively, the second ply can be obtained in the form of a prepreg from a commercial vendor, where a matrix resin is pre-impregnated into the material that comprises the second ply. In any case, the surface of the first ply of material that has not been exposed to the ceramic material is contacted with the surface of the second ply material, and the two plies are pressed together by rollers or other means to remove air and insure uniform contact.

According to another embodiment, additional plies of fiber or fabric material may be adhered to the second ply of material as part of step508. For example, a third, a fourth or more additional plies of fiber or fabric material, each being substantially identical to the second ply of fiber or fabric material, may be desired for inclusion in the fireproof panel. Then, the additional plies of fiber or fabric materials are stacked over each other, and/or the second ply of fiber or fabric material, and/or the first ply of fiber or fabric material. In another embodiment, a third ply of fiber or fabric material that is substantially similar in configuration to the first ply of fiber or fabric material (i.e., is impregnated with the ceramic material) may be desired for inclusion in the fireproof panel. Here, the epoxy material is deposited over a surface of the third ply that is intended to be unexposed and the first, second, and third plies are stacked such that the intended exposed surfaces of the first and third plies face outwardly and the second ply is disposed between the first and third plies. It will be appreciated that additional plies of fiber or fabric material may be placed between the first and third plies.

In any case, the stacked plies of fiber or fabric material are then cured under pressure to form the fireproof panel, step520. In an embodiment, a mold in which the plies are disposed is closed and heated to a temperature in a range of between about 120° C. to about 130° C. In another embodiment, the cured stacked plies of fiber or fabric material may be subjected to post-cure steps, step522. For example, the cured stacked plies may be exposed to a post cure heat treatment cycle while exposed to the air outside the mold. In an embodiment, the heat treatment cycle may include a first heat step, where the cured stacked plies are heated to a first temperature for a first time period, followed by heat treatment at a second temperature for a second time period, followed by heat treatment at a third temperature for a third time period. In one example, the first temperature may be between about 120° C. and about 130° C. and the first time period may be about 30 minutes, the second temperature may be between about 140° C. and about 160° C. and the second time period may be about 30 minutes, and the third temperature may be between about 170° C. and about 190° C. and the third time period may be about two hours.

In another embodiment of method500, after step502is performed, a multilayer structure of dry fabrics or fibers may be built up, step510. In particular, two or more plies of material may be stacked in a desired configuration. For example, two outer plies may be included. In another example, one or more inner plies may be disposed between two outer plies.

Next, a ceramic material may be impregnated into the outer plies of material, step512. The ceramic material may be applied to the outer plies in any manner similar to those described in step504. As a result, a ceramic-impregnated fabric is formed. The ceramic-impregnated fabric is then dried and heat treated, step514. In an embodiment, the ceramic-impregnated fabric is then placed in an air tight mold or a vacuum bag is secured thereover. In an embodiment in which a matrix resin has been pre-impregnated into the plies of material, the method500may proceed to steps520and522after514.

In another embodiment in which the plies of material have not been pre-impregnated with a matrix resin, the matrix resin is infused into the ceramic-impregnated fabric, step516. For example, the matrix resin may be infused into the fabric by pressure and/or vacuum. In one embodiment, a resin infusion process, such as resin transfer molding may be performed to infuse the matrix resin into the fabric. In some embodiments, after step516is performed, the method500may proceed to steps520and522.

Although the foregoing description describes a structure in which the ceramic-impregnated plies of material are on one or both of the outer surfaces of a panel, they may alternatively be disposed in the interior of a panel, in other embodiments. In yet other embodiments, distribution of the ceramic-impregnated plies of material and the plies of materials that have not been treated with the ceramic material may be stacked such that the matrix resin-impregnated plies of material appear in any other sequence other than those described above.

The following example demonstrates various embodiments of the fireproof panels and materials and the methods of fabricating the panels and materials. These examples should not be construed as in any way limiting the scope of the inventive subject matter.

EXAMPLE

Four approximately 25-inch×25-inch (63.5 cm×63.5 cm) plies of fabric made of T300 PAN-based carbon as a five harness weave from Toray Industries America, Inc. of New York, N.Y. were cut with edges taped to prevent loose fibers from peeling off. Two of these fabrics were wetted in a ceramic material made up of a sodium metasilicate solution and dried overnight by hanging in a hood. The fabrics were then dried unconstrained in a hot air oven at 120° C. for an hour. Next, the dried fabrics were secured in a mold and hot air dried for a second hour to form two ceramic-treated plies of fabrics.

The remaining two untreated fabrics were impregnated with an epoxy compound. Specifically, a mold was constructed that included two aluminum plates measuring 28-inches×28 inches (71.1 cm×71.1 cm). One of the plates had a thickness of 0.5 inch (1.27 cm), and the other plate had a thickness of 0.75 inch (1.9 cm). The plates were held together by screws along their periphery and reinforced to prevent bulging by a crossbar clamped to the thinner plate.

The mold plates were preheated to 60° C. and about 42 g of an epoxy material was applied to the exterior surface of first ply of fabric. The epoxy material included a first mixture and a second mixture at a ratio of 4:1, where the first mixture included phenol novolac at about 75% by weight, polyether elastomer at about 8.6% by weight, and ammonium phosphate salt at about 16% by weight and the second mixture, known as a hardener, included diaminodiphenylsulfone (DDS) at about 60% by weight and hindered alkyl aromatic amine at about 40% by weight. The epoxy material was chilled and ground to fine epoxy powder, and approximately 42 grams was sprinkled on a layer of release film of Kapton® (available through E. I. du Pont de Nemours and Company of Delaware) that was placed on the mold plates and spread with a squeegee. One of the plies treated with the ceramic solution was positioned on the coated layer of release film. Next, approximately 45 grams of epoxy powder was spread over the top surface of the treated ply and spread with a squeegee. A hot air gun was used to maintain the epoxy material above its softening point. A second ply consisting of untreated fabric was placed on the epoxy-treated ply. Rollers were used to establish continuous contact between the two plies and to remove air. Approximately 68 grams of epoxy powder was placed on the exposed surface of the second ply and the spreading process described above was used.

This procedure was repeated for an additional ply of fabric and for an additional outer ply, which was treated with the solution of ceramic material. A final amount of epoxy powder (approximately 45 g) was applied to the exposed surface of the remaining ceramic-treated ply. The mold was closed by tightening screws against gauge blocks with a 0.052-inch (0.13 cm) spacing to insure a uniform thickness along the edges of the stacked plies. The mold was placed in a hot air oven and heated to 125° C. for three (3) hours to form a panel. Next, the mold was opened and aluminum screens were placed on the top and bottom surfaces of the panel. The mold was lightly secured with screws, and the panel was exposed to a post cure cycle that included heat treatment for thirty (30) minutes at 125° C., thirty (30) minutes at 150° C., and two (2) hours at 180° C.

The resulting approximately 25-inch by 25-inch (63.5 cm×63.5 cm) panel had a layer-by-layer composition listed in Table 1:

Additionally, the resulting panel had a density of between about 1.45 g/cc and about 1.50 g/cc, a top surface that was completely wetted out, and a bottom surface with some dry epoxy spots without the bottom surface was positioned away from the flame in the burn test.

Before testing, a propane burner was set up and calibrated such that the average burner temperature was 2039° F. (1115.1° C.), an average burner heat flux density was 8.90 [BTU/(ft2−sec)], a ¼″ test thermocouple temperature was at 2025° F. (1107° C.). After testing, the average burner temperature was 2040° F. (1115.5° C.). It was found that the resulting panel completed a fifteen minute fire test with no signs of burn through and no opposite side ignition. Thus, the panel passed the fireproof test established by the Department of Transportation Advisory Circular 20-135.

Improved materials and/or structures have now been provided that meet fire-proof requirements. The improved fireproof panels and materials are relatively inexpensive to either obtain or manufacture and are not export-controlled. Moreover, methods of fabricating the panels and materials are relatively simple to perform and may be incorporated into the existing manufacturing processes.