Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
  • B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
  • B32B3/12—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D3/00—Making articles of cellular structure, e.g. insulating board
  • B31D3/02—Making articles of cellular structure, e.g. insulating board honeycombed structures, i.e. the cells having an essentially hexagonal section
  • B31D3/0292—Making articles of cellular structure, e.g. insulating board honeycombed structures, i.e. the cells having an essentially hexagonal section involving auxiliary operations, e.g. expanding, moistening, glue-applying, joining, controlling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D3/00—Making articles of cellular structure, e.g. insulating board
  • B31D3/02—Making articles of cellular structure, e.g. insulating board honeycombed structures, i.e. the cells having an essentially hexagonal section
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D3/00—Making articles of cellular structure, e.g. insulating board
  • B31D3/02—Making articles of cellular structure, e.g. insulating board honeycombed structures, i.e. the cells having an essentially hexagonal section
  • B31D3/0223—Making honeycomb cores, e.g. by piling a plurality of web sections or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D3/00—Making articles of cellular structure, e.g. insulating board
  • B31D3/02—Making articles of cellular structure, e.g. insulating board honeycombed structures, i.e. the cells having an essentially hexagonal section
  • B31D3/0284—Laminating honeycomb cores; applying cover sheets to core edges; working core edges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/08—Anti-corrosive paints
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
  • E04C2/34—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts
  • E04C2/36—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by transversely-placed strip material, e.g. honeycomb panels
  • E04C2/365—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by transversely-placed strip material, e.g. honeycomb panels by honeycomb structures
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/02—2 layers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
  • Y10T428/24149—Honeycomb-like
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal

Definitions

• This invention relates to a high compression strength structural made from a metallic foil.
• Core structures for composite sandwich panels from aluminum or other metallic foil are used in different applications but primary for aerospace and ground transportation where strength to weight or stiffness to weight ratios have high values.
• This invention pertains to a honeycomb comprising a plurality of interconnected walls having surfaces that define a plurality of honeycomb cells, wherein the cell walls are of a metallic foil coated with matrix resin wherein the resin comprises at least 20 weight percent of the total weight of resin plus foil.
• the invention is further directed to a composite sandwich panel comprising a resin coated metallic core coated with matrix resin and at least one facesheet attached to at least one exterior surface of the core.
• Figures 1 a and 1 b are representations of views of a hexagonal shaped honeycomb.
• Figure 2 is a representation of another view of a hexagonal cell shaped honeycomb.
• Figure 3 is an illustration of honeycomb provided with facesheets.
• Figure 4 a perspective view of a folded core structure.
• the core of this invention is a honeycomb core although other core structures such as folded core may also utilize the invention.
• the metallic foil of the core can be made from aluminum, stainless steel, or other metal or alloys of these metals. Suitable aluminum foil types include grades 3003, 5052 and 5056. The foil may be cleaned and / or etched prior to application of the coating resin. A primer coating may also be applied.
• Figure 1 a is a plan view illustration of one honeycomb 1 of this invention and shows cells 2 formed by cell walls 3.
• Figure 1 b is an elevation view of the honeycomb shown in Figure 1 a and shows the two exterior surfaces, or faces 4 formed at both ends of the cell walls. The core also has edges 5.
• Figure 2 is a three-dimensional view of the honeycomb. Shown is honeycomb 1 having hexagonal cells 2 and cell walls 3. The "T" dimension or the thickness of the honeycomb is shown in Figure 2. Hexagonal cells are shown; however, other geometric
• the foil may be coated with a matrix resin before or after formation of the honeycomb.
• the final mechanical strength of core is a result of a combination of several factors.
• the principal contributors are foil type and thickness, cell size, and final core density such as after coating with resin.
• Cell size is the diameter of an inscribed circle within the cell of a honeycomb core.
• typical cell sizes range from 1/8" - 1/4" (3.2 mm - 6.2 mm) but other sizes are possible.
• Typical final core densities are in the range of 38 - 96 kg/m 3 .
• a folded core is a 3-dimensional structure of folded geometric patterns folded from a relatively thin planar sheet material. Such folded or tessellated sheet structures are discussed in US patents 6,935,997 B2 and 6,800,351 B1 .
• a chevron is a common pattern for three dimensional folded core structures. Folded core structures are different from
• honeycomb core structures A preferred folded structure is of the type described in United States patent number 6,913,570 B2 and United States patent publication number 2010/0048078.
• Matrix Resin A preferred folded structure is of the type described in United States patent number 6,913,570 B2 and United States patent publication number 2010/0048078.
• the matrix resin used to coat the foil can be any suitable resin including but not limited to phenolic, epoxy, acrylic, polyimide,
• polybenzoxazine polyetherimide and mixtures thereof.
• United States Military Specification MIL-R-9299C specifies typical resin properties.
• the resin may also contain other materials that enhance properties or provide additional functionality to the finished core. Examples include
• thermoplastic toughening agents and fibers such as nano-fibers having a major dimension of less than 1 micrometer.
• the resin coating is present in an amount such that the resin comprises at least 20 weight percent of the total weight of resin plus foil. In some embodiments, the resin coating is present in an amount of from 20 to 70 weight percent of the total weight of resin plus foil. In some embodiments, the resin coating is present in an amount of from 20 to 40 weight percent or even from 40to 70 weight percent of the total weight of resin plus foil.
• a composite sandwich panel comprises a metallic honeycomb core coated with matrix resin as described above and at least one facesheet attached to at least one exterior surface of the core.
• at least one facesheet is attached to both exterior surfaces of the core.
• FIG 3 shows a structural composite sandwich panel 5 assembled from a honeycomb core 6 with facesheets 7 and 8, attached to the two exterior surfaces of the core.
• the preferred facesheet material is a prepreg, a fibrous sheet impregnated with thermoset or thermoplastic resin, although metallic or plastic face sheets may also be utilized. With metallic face sheets, and in some circumstances with prepreg and plastic facesheets, an adhesive film 9 is also used. Normally there are at least two prepreg facesheets on either side of the core.
• the reinforcing fiber of the prepreg is typically carbon, glass, aramid or a combination of these fibers.
• the reinforcing fibers may be provided in the form of a woven fabric, a nonwoven fabric or a
• Core density was measured in accordance with ASTM C 271 .
• Compression strength of the core was measured in accordance with ASTM C 365.
• Electrical resistance was measured by making a 7.6 cm x 7.6 cm sandwich structure in which a 178 gsm, 0.02 mm thick stainless steel plate was adhesively bonded to a 1 .5 cm thick slice of core. The electrical resistance through the panel was measured by placing a contact probe of a multimeter on each steel plate.
• the core of Comparative Example A was treated with acetone, dried, then treated with chromic acid solution by immersion at 70 degrees C for 10 minutes, rinsed thoroughly with water and dried.
• the dried core was then dipped in a solution of GP® 445D05 RESI-SET® phenolic resin supplied by Georgia-Pacific Resins, Inc., Decatur, GA.
• the core was heat treated to cure the resin using a step cure cycle of 15 minutes at 82 degrees C, 15 minutes at 121 degrees C, and 60 minutes at 182 degrees C.
• the dipping and curing steps were repeated for the second time with the core sliced flipped over in the second dipping process.
• the resin content in the final honeycomb core was 21 weight percent of the total weight of core plus resin. Compression testing was repeated and the results shown in Table 1 .
• Table 1 Table 1
• test sandwich panel was 0.2 Ohms for uncoated core and 0.6 Ohms for resin coated core thus demonstrating the additional benefit of reduced conductivity (increased resistivity) provided by the resin coated metal core.
• This is an attractive feature in 15 reducing undesirable galvanic corrosion in sandwich panels comprising metallic core and conductive facesheets such as metallic or carbon facesheets.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Chemical & Material Sciences (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Laminated Bodies (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Citations (11)

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• 2015
  • 2015-01-06 US US14/590,172 patent/US20150190981A1/en not_active Abandoned
  • 2015-01-07 WO PCT/US2015/010455 patent/WO2015108732A1/en not_active Ceased
  • 2015-01-07 CN CN201580003766.8A patent/CN105899624A/zh active Pending
  • 2015-01-07 JP JP2016545341A patent/JP2017509507A/ja not_active Abandoned
  • 2015-01-07 CA CA2933102A patent/CA2933102A1/en not_active Abandoned
  • 2015-01-07 EP EP15701606.4A patent/EP3092275A1/en not_active Withdrawn

Patent Citations (11)

Non-Patent Citations (3)

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