Ceramifiable fiber reinforced tape

Abstract

Ceramifiable tapes can be configured to form stable structures at elevated temperatures. Such ceramifiable tapes can be used to improve the fire resistance of construction materials and prepare construction materials such as composite boards. The ceramifiable tapes include a plurality of unidirectional glass fibers in a ceramifiable matrix composed of an amorphous polyethylene terephthalate, an amorphous silica and an alkaline compound, e.g., a metal carbonate.

Description

CERAMIFIABLE FIBER REINFORCED TAPECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all benefit of U.S. Provisional Patent Application No. 63 / 678,042, filed on July 31, 2024, the entire disclosure of which is fully incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure is directed to ceramifiable tapes configured to form stable structures at elevated temperatures. The ceramifiable tapes of the present disclosure include a plurality of unidirectional continuous glass fibers embedded in a ceramifiable matrix.BACKGROUND

[0003] Continuous fiber reinforced (CFR) thermoplastic tapes and laminates are used in a wide variety of applications due to their light weight, high strength and impact resistance. However, when exposed to elevated temperatures, such as those that occur during a fire, CFR tapes generally do not act as a flame barrier even when they include traditional flame retardants.

[0004] In addition, regulations are placing increasing demands for higher fire protection requirements in various applications such as building & construction panels, electric vehicle and grid storage battery enclosures, etc. Adding a fire-resistant or retardant coating to materials can improve their performance in a fire, however, such coatings add manufacturing complexity and cost. Often the coating required is quite thick and increases the overall weight. Hence a continuing need exists to improve the fire resistance of materials particularly improvements that offer light weight and / or lower costs.SUMMARY OF THE DISCLOSURE

[0005] Advantages of the present disclosure include ceramifiable tapes that can form a stable ceramic flame barrier when exposed to elevated temperatures.

[0006] In certain implementations, a ceramifiable tape is provided which includes a plurality of unidirectional continuous glass fibers embedded in a ceramifiable matrix. The ceramifiable matrix includes: (a) an amorphous polyethylene terephthalate polymer; (b) anamorphous silica; and (c) an alkaline compound, e.g., a metal carbonate. The ceramifiable matrix can include the amorphous polyethylene terephthalate in the range of about 80 wt% to about 95 wt%, based on the total weight of the ceramifiable matrix. The amorphous silica can include fumed silica, silica gel, precipitated silica, or any combination thereof. The silica can be in a range of from about 2 wt% to about 8 wt% based on the total weight of the ceramifiable matrix. The alkaline compound can include a metal carbonate such as sodium carbonate, calcium carbonate, potassium carbonate, hydrotalcite, or any combination thereof. Further, the ceramifiable tape can include the alkaline compound, e.g., metal carbonate, in a range of from about 0.85 wt% to about 6.6 wt% based on the total weight of the ceramifiable matrix.

[0007] The plurality of unidirectional continuous glass fibers can comprise about 40 wt% to about 80 wt%, based on a total weight of the ceramifiable tape. The glass fibers can include a variety of glass fibers such as E-glass, A-glass, C-glass, D-glass, S-glass, ECR-glass, AR glass, R-glass, or any combination thereof.

[0008] In some aspects, the ceramifiable tape is configured to form a self-supporting structure upon exposure to a temperature in a range of from about 350 °C to about 1,000 °C, such as upon exposure to a temperature in a range of from about 350 °C to about 900 °C or from about 350 °C to about 850 °C.

[0009] In other implementations, a ceramified composition can be prepared by providing a ceramifiable tape and heating the ceramifiable tape to a temperature of from about 350 °C to about 1000 °C to form a self-supporting structure.

[0010] Advantageously, ceramifiable tapes of the present disclosure are generally flexible and advantageously can be applied to, or used to prepare, construction materials such as a composite board, etc. to increase the fire resistance of such construction materials.

[0011] Additional advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only certain embodiments are shown and described, simply by way of illustration of carrying out certain subject matter. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference is made to the attached drawings, wherein elements having the same reference numeral designations represent similar elements throughout and wherein:

[0013] FIG. 1 illustrates a ceramifiable tape construction including a plurality of unidirectional continuous glass fibers embedded in the ceramifiable matrix according to an implementation of the present disclosure.

[0014] FIG. 2 schematically illustrates a perspective view of ply of two layers of the ceramifiable tape having different relative orientations of fibers in the layers according to an implementation of the present disclosure.

[0015] FIG. 3 illustrates a perspective view of a composite board including a core and ceramifiable tape layers adhered to the first and second major surfaces of the board according to an implementation of the present disclosure.

[0016] FIG. 4 is a photograph comparing a ceramifiable tape of the present disclosure to a comparative example after exposure to relatively low temperatures (400 °C).

[0017] FIG. 5 A and FIG. 5B are photographs comparing a ceramifiable tape of the present disclosure to a comparative example after exposure to intermediate temperatures (550 °C and 750 °C).

[0018] FIG. 6 is a photograph comparing a ceramifiable tape of the present disclosure to a comparative example after exposure to high temperatures (1000 °C).

[0019] FIG. 7 is a photograph comparing a ceramifiable tape of the present disclosure to a comparative example after exposure to elevated temperatures showing temperature induced deformation (bending) of the respective tapes.

[0020] FIG. 8 is a photograph comparing a ceramifiable tape of the present disclosure to a comparative example after exposure to elevated temperatures (850 °C, 900 °C, and 1000 °C).DETAILED DESCRIPTION OF THE DISCLOSURE

[0021] The disclosure may be more fully appreciated by reference to the following description, including the following definitions and examples. Certain features of the disclosed compositions and methods which are described herein in the context of separate aspects, may also be provided in combination in a single aspect. Alternatively, various features of the disclosed compositions and methods that are, for brevity, described in the context of a single aspect, may also be provided separately or in any sub-combination.

[0022] Unless otherwise defined herein, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0023] As employed above and throughout the disclosure, the following terms and abbreviations, unless otherwise indicated, shall be understood to have the following meanings.

[0024] As used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0025] As used in the specification including the appended claims, when a range of values is expressed, such range includes from the one particular value and / or to the other particular value. All ranges are inclusive and combinable. Further, reference to values stated in ranges includes each and every value within that range. The term “about” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass reasonable variations of the value.

[0026] The present disclosure is directed to ceramifiable tapes that can generally form stable ceramic structures, e.g., fused glass fiber matrix, upon exposure to elevated temperatures such as those experienced during a fire conditions. Advantageously, the ceramifiable tapes of the present disclosure can form self-supporting structures, i.e., the self-supporting structures remain rigid and do not undergo significant heat induced deformation or flow. They also undergo little if any shrinkage following elevated temperature exposure. The ceramifiable tapes further can form ceramic structures relatively quickly and at a lower range of elevated temperatures, e.g., starting at a temperature as low as 350 °C.

[0027] Advantageously, ceramifiable tapes of the present disclosure are generally flexible and advantageously can be included as one or more layers on various articles, structures, etc. to increase the fire resistance of articles, shapes and / or structures. In one aspect, ceramifiable tapes of the present disclosure can be included on building materials such as on one or more major surfaces of construction board or insulation board.

[0028] The ceramifiable tapes of the present disclosure include a plurality of unidirectional continuous glass fibers embedded in a ceramifiable matrix. The ceramifiable matrix is composed of (a) an amorphous polyethylene terephthalate polymer; (b) an amorphous silica; and (c) an alkaline compound, e.g., a metal carbonate.

[0029] The ceramifiable tapes of the present disclosure include a significant amount of unidirectional continuous glass fibers, e.g., at least about 40 wt% based on a total weight of the ceramifiable tape. Such ceramifiable tapes can form a fused glass matrix when exposed to elevated temperatures which results in a structure that resists significant shrinkage. In certain aspects, the tape can include at least 40 wt%, 45 wt%, 50 wt% and up to and including about 80 wt% glass fibers, based on the total weight of the ceramifiable tape. The amount of glassfibers in the composition can further include ranges from about 40 wt% to about 80 wt% and any ranges therein.

[0030] Advantageously, the glass fibers used in the ceramifiable tapes have a relatively high softening point (e.g., greater than or equal to 700 °C) to resist deformation upon exposure to elevated temperatures. For example, the glass fibers can include one or more of E-glass (softening point of approximately 846 °C), A-glass (softening point of approximately 705 °C), C-glass (softening point of approximately 750 °C), D-glass (softening point of approximately 771 °C), S-glass (softening point of approximately 1056 °C), ECR-glass (softening point of approximately 882 °C), AR glass (softening point of approximately 773 °C), R-glass (softening point of approximately 952 °C), or any combination thereof.

[0031] In some aspects, the plurality of unidirectional continuous fibers embedded in the ceramifiable matrix can be in a tow, yarn, end, pic, or roving. In some aspects, the plurality of unidirectional continuous fibers can include a sizing composition. The sizing composition both protects the fiber during processing as well as promotes chemical or mechanical bonding between the ceramifiable matrix and the continuous fibers. Sizing is typically applied by the fiber manufacturer. For example, the sizing composition can comprise a film former, a lubricant, a coupling agent, or a combination thereof.

[0032] In further aspects, each of the plurality of unidirectional continuous fibers can have an average diameter from about 1 pm to about 40 pm, e.g., from about 13 pm to about 24 pm. In other aspects, a tow, yarn, end, pic, or roving of the plurality of unidirectional continuous fibers can have an average linear mass density from about 100 TEX to about 4400 TEX, e.g., from about 276 TEX to about 4400 TEX. (TEX is a unit of measure in grams per 1,000 meters. Also, the ranges above are a generalization of various fiber filament diameters and TEX.)

[0033] Advantageously, the ceramifiable matrix of the present disclosure includes an amorphous polyethylene terephthalate polymer. Such an amorphous polyethylene terephthalate polymer allows a ceramifiable tape to directly adhere to many building materials including building panels. The amorphous polyethylene terephthalate polymer also appears to have stronger interaction with the ceramifiable additives (amorphous silica and alkaline compound) and facilitates the ceramification process. The amount of amorphous polyethylene terephthalate polymer (aPET) in ceramifiable matrix can be at least 60 wt%, based on the total weight of the ceramifiable matrix, such as at least 70 wt%, 75 wt%, 80 wt% and up to and including 95 wt%, such as in a range of from about 80 wt% to about 90 wt% or 95 wt%, based on the total weight of the ceramifiable matrix.

[0034] The ceramifiable matrix of the present disclosure further includes a silica, such as one or more of fumed silica, silica gel, precipitated silica, amorphous silica, or any combination thereof. It is believed that the silica in the composition facilitates fusing of glass fibers in the tape at elevated temperatures. It is believed that free (isolated or geminal) surface silanol groups on the silica and glass fibers can facilitate condensation reactions among silica and glass fibers. In some aspects, the silica can have a diameter in a range of from about 3 nm to about 150 nm. For example, precipitated silica and fume silica can have primary structures with an average diameter of about 5 nm to 100 nm and agglomerated average diameters of about 1 pm to 40 pm. The ceramifiable matrix of the present disclosure can include silica in an amount of at least 1.5 wt%, such as at least 2 wt%, 3 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, and any amounts therebetween, based on the total weight of the ceramifiable matrix. For example, a ceramifiable tape can include silica in a range of from about 2 wt% to about 8 wt% and any ranges therebetween.

[0035] Ceramifiable matrices of the present disclosure further include an alkaline compound, such as a Group I or Group II metal salts, such as a metal carbonate. As one skilled in the art may appreciate, Group I metal salts are more reactive than Group II metal salts. It is believed that the alkaline compound in the ceramifiable matrix can activate surfaces of the silica and glass fiber, as well as optional metal silicates that may be included in the matrix, which in turn facilitates silanol condensation reactions and fusing of silica and glass fibers to themselves and to each other. The alkaline compound may also catalyze decomposition of the matrix polymer, which may further activate the silica surface by generating more silanol groups.

[0036] In some aspects, the alkaline compound can be one or more of an alkali metal carbonate, such as sodium or potassium carbonate, calcium carbonate, hydrotalcite, or any combination thereof. The ceramifiable tapes of the present disclosure can include the alkaline compound, e.g., metal carbonate, in an amount of at least 0.5 wt%, such as at least 0.85 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt% and upto about 8 wt% any amounts therebetween, based on the total weight of the ceramifiable matrix. For example, a ceramifiable tape can include the alkaline compound in a range of from about 0.85 wt% to about 6.6 wt% based on the total weight of the ceramifiable matrix.

[0037] In an implementation of the present disclosure, a molar ratio of silica to alkaline compound, e.g., metal carbonate, is from about 1.5: 1 to about 6: 1, about 2: 1 to about 5: 1, or about 3: 1 to about 4: 1. It is believed the alkaline compound catalyzes silanol condensation reaction. However, higher alkaline content could also weaken the silicate glass network.Therefore, there seems to be a certain silica to alkaline compound ratio for the ceramifiable tapes of the present disclosure that leads to a quick formation of silicate glass network with good thermal and mechanical properties when exposed to elevated temperatures, such as those that occur during a fire.

[0038] The ceramifiable tapes of the present disclosure can further include optional additives, which can improve thermal and / or mechanical characteristic of the composition. For example, the ceramifiable tapes of the present disclosure can include, based on the total weight of the composition, greater than 0 wt% to about 20 wt% additives. Such additives can be one or more of a metal silicate (e.g., a calcium silicate, magnesium silicate, aluminum silicate, wollastonite, or sepiolite), antioxidants, flame retardants, thermally conductive additives, electrically conductive additives, or any combination thereof. Additives such as these metal silicates can improve thermal and mechanical properties of the ceramifiable tape and further the resulting ceramified composition after exposure to elevated temperatures.

[0039] FIG. 1 illustrates a ceramifiable tape 100 including a plurality of unidirectional continuous fibers 102 embedded in the ceramifiable matrix 120. The tape can have a first major surface 110a and a second major surface 110b. FIG. 1 further illustrates the continuous glass fibers as being oriented in essentially the same direction (Z direction). That is, the plurality of continuous fibers are unidirectional.

[0040] As further shown with reference to the X, Y, and Z axes, the ceramifiable tape can have a length in the Z direction, a width in the X direction and a thickness in the Y direction. The ceramifiable tape length can be greater than or similar to its width, but the tape thickness is substantially less than either its length or width. For example, the ceramifiable tape can have a thickness (Y direction) in a range from about 0.1 mm to about 1 mm (about 4 mil to about 40 mil), such as from about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm to about 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, including any value or range therebetween.

[0041] In some implementations, a ceramifiable tape can be stacked on top of another forming a multi ply of layers of ceramifiable tape. The ply can be laminated by heating layers of ceramifiable tape at a temperature below the decomposition temperature of the aPET. It will be appreciated that such a laminate can include additional layers of the ceramifiable tape, e.g., at least 3, 4, 5, 6, 7, 8, etc. layers of ceramifiable tape. For example, a ply or laminate can include four to six layers of ceramifiable tape (e.g., a quad ply or 6 ply) which can be used to improve the fire resistance of a material as well as reinforce the material.

[0042] In addition, the fibers in the various ceramifiable tape layers can be oriented in the same or in different directions relative to other fibers in ceramifiable tape layers. For example,a ply or laminate can include a first layer of ceramifiable tape in which the plurality of unidirectional continuous fibers are oriented in a first direction and a second layer of ceramifiable tape in which the plurality of unidirectional continuous fibers are oriented at an angle greater than or equal to 0° and less than or equal to 90° with reference to the plurality of unidirectional continuous fibers in the first layer of ceramifiable tape, e.g., the angle of the second fibers relative to the first fibers can be at about 0°, 10°, 20°, 30°, 40°, 50°, 60°, 67°, 70°, 80°, 90°, or any value or range therebetween.

[0043] For example, FIG. 2 illustrates a laminate of two ceramifiable tapes with different relative orientations of fibers in layers of the tape. In particular, FIG. 2 illustrates a perspective view of a ceramifiable tape laminate 200 including two layers of ceramifiable tape, e.g., first layer of ceramifiable tape 210a and second layer of ceramifiable tape 210b. For this example, the first layer of the tape 210a includes a first plurality of unidirectional continuous fibers 202 that are oriented in a first direction, i.e., at 0° degrees from the Z direction (or at a 90° angle from the X direction). As further shown for this example, the second layer of the ceramifiable tape 210b includes a second plurality of unidirectional continuous fibers 204 that are oriented in a second direction, i.e., at 90° degrees from the Z direction (or at 0° degree angle from the X direction). Hence, the plurality of unidirectional continuous fibers in the second layer are oriented at an angle of about 90° with reference to the first direction of the plurality of unidirectional continuous fiber in the first layer of ceramifiable tape (e.g., the second ceramifiable tape is rotated 90° from the Z-axis).

[0044] The ceramifiable tapes of the present disclosure can reinforce various structures due to the plurality of continuous glass fibers and can further improve the fire resistance of underlying materials due to the components of the ceramifiable matrix. Further, the ceramifiable tapes of the present disclosure can exhibit limited change in shape following exposure to elevated temperatures such as those likely to be encountered in a fire condition. An advantage of the ceramifiable tapes of the present disclosure is that they can resist shrinking after exposure to elevated temperatures. While the aPET polymer component of the ceramifiable matrix decomposes, the silica component tends to fuse the glass fibers together to form a fused glass fiber matrix. For example, the ceramifiable tapes of the present disclosure can resist shrinking as determined by measuring a test specimen along a length direction in which the reduction in length is less than 10%, such as less than 5% and even less than 2% after exposing the test specimen to elevated temperatures at 900 °C.

[0045] In addition, the ceramifiable tapes of the present disclosure can form self-supporting structures, i.e., the self-supporting structures remain rigid and do not undergo significant heatinduced deformation or flow. For example, the ceramifiable tapes of the present disclosure can be configured to form self-supporting structures upon heating the ceramifiable tape to a temperature in a range from about 350 °C to about 1,000 °C, such as from about 350 °C to about 900 °C or from about 350 °C to about 850 °C. The ceramifiable tapes disclosed herein may advantageously convert to a ceramic structure at a temperature as low as 350 °C. While the ceramifiable tape is ceramifiable at temperatures up to and including 1,000 °C, it should be understood that ceramification may occur at temperatures above 1,000 °C. For example, fires may produce hotter temperatures than 1,000 °C and ceramification is possible under these conditions. Further, such self-supporting structures can be formed in a relatively short period of time upon exposure to the elevated temperatures such as within about 5 minutes (300 seconds). In other aspects, such self-supporting structures can be formed upon exposure to the elevated temperatures on or after 300 seconds.

[0046] Advantageously, ceramifiable tapes of the present disclosure can be applied to, and used to prepare, various building materials including construction board. For example, the ceramifiable tapes of the present disclosure can be applied to a construction board having a first major surface and an opposing second major surface composed and one or more layers ceramifiable tape adhered to either or both of the first and / or second major surfaces of the board. The construction board can be composed of a cellulose, polymer, cementitious based material, or a combination thereof.

[0047] In some implementations, the ceramifiable tapes of the present disclosure can be used to prepare a construction board. For example, and as illustrated in FIG. 3, a composite board 300 can include a core 330 having a first major surface 332 and an opposing second major surface 334. One or more layers of ceramifiable tape can be adhered to the first and second major surfaces of the core. As illustrated in FIG. 3, a ceramifiable tape 310a can be adhered to the first major surface 332 and a second ceramifiable tape adhered to the opposing second major surface 334 of the core 330. In this construct, the ceramifiable tapes 310a and 310b act as a skin for the composite board.

[0048] In some aspects, the core can have a foam or honeycomb configuration. The core can be composed of a cellulosic material such as wood (e.g., balsa wood) and / or a polymer including a polymer configured as a foam or honeycomb configuration. Polymers that can be used for a core include, for example, a thermoset, such as a polyurethane and a foam thereof, a polyisocyanurate, and a foam thereof, etc. A thermoplastic and thermoplastic foams can also be used for the core such as a polyethylene terephthalate (PET), such as a fire-retardant polyethylene terephthalate (FR PET), styrene acrylonitrile (SAN), a polyether imide (PEI), etc.and foams thereof. The ceramifiable tapes of the present disclosure can be bonded to construction materials including construction panels and composite board by direct thermal bonding. Alternatively, or in addition, the ceramifiable tapes can be adhered to the materials by adhesive thermoplastic film, glue, or any combination thereof.

[0049] In some aspects, the board thickness, including the ceramifiable tape(s) thereon, can range from about 1 mm to about 300 mm. In a non-limiting example, the ceramifiable tape can have a thickness of from about 0.5 mm to about 3 mm. In other examples, a composite board with a core can have a core thickness ranging from about 2 mm to about 299 mm.EXAMPLES

[0050] The following examples are intended to further illustrate certain aspects of the subject technology and are not limiting in nature. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances and procedures described herein.Example 1

[0051] A ceramifiable masterbatch (MB) was prepared by mixing all raw materials in a 27 mm twin screw extruder (L / D = 60). Amorphous polyethylene terephthalate (aPET) resin was fed at the main feed (barrel 1). The ceramifiable additives (noted in Table 1 below) were premixed and side-fed after the first mixing zone (barrel 4). The temperature in all zones was set at 220 °C, except the first heating zone was set at 140 °C. The extruder screw rotated at 350 rpm. The extrudate was cooled on the belt and pelletized.

[0052] Samples of unidirectional (UD) glass fiber ceramifiable tape were prepared using a composite tape processing line. E-glass strands were pulled along the machine direction while a polymer melt blend (aPET and ceramifiable MB) was extruded in the orthogonal direction. The polymer melt blend was fed into a crosshead impregnation die where the E-glass strands and polymer melt were consolidated into a single unidirectional tape, whereupon said tape was cooled and wound onto a core. The glass fiber content of the formed tape was 50% by weight and extrusion temperatures of the polymer blend ranged from 180 °C to 250 °C, with overall tape process line speeds of 10 ft. / min to 15 ft. / min. Multi-layer laminates were further made by cutting and laminating multiple unidirectional ceramifiable tapes according to the angle of orientation of glass fiber configuration illustrated in FIG 2.Comparative Example

[0053] Comparative UD tape samples were also prepared using the same apparatus and process as Example 1, except no ceramifiable MB was added when preparing the tape. Thesamples were prepared using ingredients and amounts (expressed as wt% based on the total weight of the composition) as shown in Table 1 below.Table 1

[0054] Tensile and flexural properties of tape samples were determined on a universal testing machine according to ASTM D3039 (Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials) and ASTM D790 (Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials). Samples were conditioned at a temperature of 23.0 °C and 50% humidity prior to measurement. A test orientation of 0° was used with a crosshead speed of 50 mm / min for D3039 tensile test. A six-ply laminate was used for D790 flexural test and span-to-depth ratio was set at 36: 1. Tensile and flexural properties are provided in Tables 2 and 3 below, respectively.Table 2Table 3

[0055] As shown by the data above, neither tensile properties (tensile strength and modulus) nor flexural properties (bend strength and modulus) were significantly impacted byincorporation of ceramifiable additives (silica and sodium carbonate) to form a ceramifiable tape.

[0056] Ceramification test

[0057] The ceramification test was carried out by placing samples (from Example 1 and Comparative Example) in a pre-heated muffle furnace at temperatures of 400 °C, 450 °C, 550 °C, 650 °C, 750 °C, 850 °C, 900 °C, and 1000 °C for 10 minutes, then taken out of the muffle furnace and air-cooled. The nominal size of a sample (length x width x height) was 25.4 mm x 50.8 mm x 1 mm.

[0058] The behavior of the comparative samples can be categorized in three groups depending on the ceramification temperature. At relatively low temperatures (< 450 °C, below peak mass loss rate temperature of polyethylene terephthalate), the aPET polymer matrix was not completely burned off of the comparative example and the polymer residues maintained a somewhat cohesive structure. However, the comparative samples underwent significant heat induced deformation. Some fiber bundles were broken off (as shown in FIG. 4 as Comp. Ex.). In the intermediate range of temperatures (between 450 °C and 750 °C), the comparative samples became loose fiber bundles where the aPET polymer matrix was completely burned off (as shown in FIGS. 5A & 5B as Comp. Ex.). At high temperatures (> 850 °C), a more cohesive structure was formed for the comparative sample but with significant shrinkage (as shown in FIG. 6 as Comp. Ex.).

[0059] In contrast to the comparative samples, the sample prepared from Example 1 with a ceramifiable matrix maintained structural integrity over the whole range of elevated temperatures (from 400 °C to 1000 °C). See FIGS. 4, 5A, 5B, and 6 as Example 1. Only a small amount of shrinkage was observed at high temperatures (> 850 °C).

[0060] Dimensional Stability (Shrinkage Tests)

[0061] The amount of dimensional change caused by exposure of a material to elevated temperature was determined by measuring the dimensions of the samples before and after the ceramification test. The samples (quad-ply laminates) were maintained at the maximum temperature for 15 minutes before taking them out of the furnace. Three samples were tested for each data point. The results in each dimension were reported as a percentage change in Table 4.Table 4

[0062] The quad-ply laminates with a ceramifiable matrix showed minimal amounts of shrinkage in both dimensions even at 1000 °C and the amount of shrinkage appeared to be independent of ceramification temperature, indicating that this small amount of shrinkage is likely due to the residual stresses incurred during the tape / lamination process, rather than due to the ceramification process. The comparative samples showed significant amount of shrinkage and the amount of shrinkage increased nonlinearly with ceramification temperature. A ceramifiable tape with a ceramifiable matrix can stabilize the tape structure when exposed to elevated temperatures and prevent it from shrinking and breaking open.

[0063] Heat-induced deformation was evaluated by measuring bending angle after the ceramification test. It was determined by placing a specimen with a 1 cm portion projecting out from the edge of supporting refractory block. Bending angle was estimated as shown in FIG. 7 and was reported as an average of both sides of tested specimen. The effect of ceramification temperature on bending angle is shown in Table 5. Tape samples with a ceramifiable matrix were able to support their own weight without markedly bending over the edge of the support. The bending angles were less than 20° even at 1000 °C. On the contrary, comparative samples showed pronounced heat induced deformation and bending angle of the sample reached 80° at 900 °C.Table 5

[0064] Ceramification under slow firing conditions

[0065] A muffle furnace was pre-heated to 200 °C. Test specimens were placed in the muffle furnace once the temperature reached 200 °C. It was then subsequently heated to a maximum temperature of 850 °C, 900 °C, or 1000 °C, followed by holding at maximum temperature for 15 minutes. These conditions are representative of exposure to an elevated temperature experienced under fire conditions.

[0066] Under these conditions, comparative samples required higher temperature (above 900 °C) to maintain a cohesive structure. The amount of shrinkage for the comparative samples also increased to 38%. See FIG. 8 Comp. Ex. Tape samples with a ceramifiable matrix showed almost no shrinkage (about 2%) as shown in FIG. 8 as Example 1.

[0067] As shown by the data above, a ceramifiable tape including a plurality of unidirectional continuous glass fibers embedded in a ceramifiable matrix according to the present disclosure can form a stable ceramic flame barrier when exposed to elevated temperatures.

[0068] Only certain features and aspects of the present disclosure and examples of their versatility are shown and described in the present disclosure. It is to be understood that the technology disclosed herein is capable of use in various other combinations and environments and is capable of changes or modifications. Thus, for example, those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances, procedures and arrangements described herein. Such equivalents are considered to be within the scope of the invention and are covered by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A ceramifiable tape, comprising: a ceramifiable matrix comprising: an amorphous polyethylene terephthalate (aPET) polymer; an amorphous silica; and an alkaline compound; and a plurality of unidirectional continuous glass fibers embedded in the ceramifiable matrix.

2. The ceramifiable tape of claim 1, wherein the ceramifiable matrix comprises the aPET polymer in the range of about 85 wt% to about 95 wt%, based on the total weight of the ceramifiable matrix.

3. The ceramifiable tape of claim 1 or claim 2, wherein the amorphous silica comprises fumed silica, silica gel, precipitated silica, or a combination thereof.

4. The ceramifiable tape of any one of the preceding claims, wherein the ceramifiable matrix comprises the amorphous silica in the range of about 2 wt% to about 8 wt%, based on a total weight of the ceramifiable matrix.

5. The ceramifiable tape of any one of the preceding claims, wherein the alkaline compound comprises sodium carbonate, calcium carbonate, potassium carbonate, hydrotalcite, or a combination thereof.

6. The ceramifiable tape of any one of the preceding claims, wherein the ceramifiable matrix comprises the alkaline compound in the range of about 0.85 wt% to about 6.6 wt%.

7. The ceramifiable tape of any one of the preceding claims, wherein a molar ratio of the amorphous silica to the alkaline compound is about 1.5: 1 to about 6: 1.

8. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers have a softening point of greater than or equal to 700 °C.

9. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers are present in an amount of about 40 wt% to about 80 wt%, based on a total weight of the ceramifiable tape.

10. The ceramifiable tape of any one of the preceding claims, the plurality of unidirectional continuous glass fibers have an average diameter from 13 pm to 24 pm.

11. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers have an average linear mass density from 276 TEX to 4400 TEX.

12. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers are in a tow, yarn, end, pic, or roving.

13. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers comprise E-glass, A-glass, C-glass, D-glass, S-glass, ECR-glass, AR glass, R-glass, or a combination thereof.

14. The ceramifiable tape of any one of the preceding claims, wherein the plurality of unidirectional continuous glass fibers comprise a sizing composition comprising a film former, a lubricant, a coupling agent, or a combination thereof.

15. The ceramifiable tape of any one of the preceding claims, wherein the ceramifiable matrix further comprises, based on the total weight of the ceramifiable matrix, greater than 0 wt% to about 20 wt% additives, the additives comprising metal silicates, calcium silicates, magnesium silicates, aluminum silicates, wollastonite, sepiolite, or a combination thereof.

16. The ceramifiable tape of any one of the preceding claims, wherein the tape is capable of forming a self-supporting ceramic structure on exposure to a temperature of at least about 350 °C.

17. The ceramifiable tape of claim 16, wherein the tape is capable of forming a self- supporting ceramic structure on exposure to a temperature in the range of about 350 °C to about 1000 °C.

18. The ceramifiable tape of claim 16, wherein the tape is capable of forming a self- supporting ceramic structure on exposure to a temperature in the range of about 350 °C to about 900 °C.

19. The ceramifiable tape of claim 16, wherein the tape is capable of forming a self- supporting ceramic structure on exposure to a temperature in the range of about 350 °C to about 850 °C.

20. The ceramifiable tape of any of claims 17-19, wherein the tape is capable of forming the self-supporting ceramic structure on or after 300 seconds.

21. The ceramifiable tape of any preceding claim, wherein: the ceramifiable matrix is a first cermifiable matrix and the plurality of unidirectional continuous glass fibers is a first plurality of unidirectional glass fibers embedded in the first ceramifiable matrix to form a first layer of the ceramifiable tape; the first layer of the ceramifiable tape has a first major surface and an opposing second major surface; the ceramifiable tape further comprises a second layer comprising a second ceramifiable matrix and a second plurality of unidirectional continuous glass fibers embedded in the second ceramifiable matrix; and the second layer is adhered to the second major surface of the first layer of the ceramifiable tape.

22. The ceramifiable tape of claim 21, wherein the first plurality of unidirectional continuous glass fibers of the ceramifiable tape is oriented in a first direction and the second plurality of unidirectional continuous glass fibers is oriented at an angle greater than 0° and less than or equal to 90° with reference to the first direction.

23. The ceramifiable tape of claim 21, wherein the first plurality of unidirectional continuous glass fibers of the ceramifiable tape is oriented in a first direction and the second plurality of unidirectional continuous glass fibers is oriented an angle that is about 90° with reference to the first direction.

24. A composite board comprising; a board, wherein the board has a first major surface and an opposing second major surface; and the ceramifiable tape of any one of the preceding claims adhered to the first major surface of the board.

25. The composite board of claim 24, wherein the board comprises a core, wherein the core has a foam or honeycomb configuration.

26. The composite board of claim 24, wherein the core comprises a thermoplastic.

27. A method of preparing a ceramified tape comprising: providing a ceramifiable tape comprising: a matrix comprising:(a) an amorphous polyethylene terephthalate (aPET);(b) an amorphous silica; and(c) an alkaline compound; and a plurality of unidirectional continuous glass fibers embedded in the ceramifiable matrix; and heating the ceramifiable tape at a temperature of at least about 350 °C.

28. The method of claim 27, wherein the step of heating the ceramifiable tape is performed in the temperature range of about 350 °C to about 1,000 °C.

29. The method of claim 27, wherein the step of heating the ceramifiable tape is performed in the temperature range of about 350 °C to about 900 °C.

30. The method of claim 27 or claim 28, wherein the step of heating the ceramifiable tape is performed in the temperature range of about 350 °C to about 850 °C.

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