PatentDe  


Dokumentenidentifikation EP0575336 10.04.1997
EP-Veröffentlichungsnummer 0575336
Titel VERFAHREN ZUR HERSTELLUNG VON BAUPLATTEN UND SO HERGESTELLTE PLATTEN
Anmelder E.I. du Pont de Nemours & Co., Wilmington, Del., US
Erfinder EFFING, Michael, Josef, D-61267 Neu-Anspach, DE;
NOLLEN, Dennis, Arthur, Newark, DE 19711, US;
OKINE, Richard, Kafue, Wilmington, DE 19803, US;
WALRAVE, Albertus, Pieter, Newark, DE 19713, US
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 69125031
Vertragsstaaten DE, ES, FR, GB, IT, NL
Sprache des Dokument En
EP-Anmeldetag 12.12.1991
EP-Aktenzeichen 929027563
WO-Anmeldetag 12.12.1991
PCT-Aktenzeichen US9109146
WO-Veröffentlichungsnummer 9211121
WO-Veröffentlichungsdatum 09.07.1992
EP-Offenlegungsdatum 29.12.1993
EP date of grant 05.03.1997
Veröffentlichungstag im Patentblatt 10.04.1997
IPC-Hauptklasse B29B 13/02
IPC-Nebenklasse B32B 31/00   B29C 51/14   B29C 43/20   

Beschreibung[en]

This invention relates to a method for forming a contoured shape from a structural panel having a core faced with thermoplastic resin facings and a decorative film adhered to at least one facing.

Contoured sandwich panels for interiors of commercial aircraft have been made with facings composed with reinforcing fibers such as glass, carbon and p-aramid in thermoset resins like phenolics or epoxies and core materials of either honeycomb or foam. One technique to make contoured panels is to hand-lay up high performance pre-impregnated fabrics of phenolic or epoxy resin on either side of the core and form the assembly in a press operation. Under applied pressure the panel will be cured at temperatures between 125°C and 175°C for approximately 60 to 90 minutes. After the curing cycle the panels are placed on a cooling fixture to control the dimensional tolerances. US-A-4,598,007 discloses such a method wherein the facings comprise a reinforced cured vinyl styrylpyridine-bismaleimide copolymer.

Most of the interior panels will then be decorated with decorative laminate films (DECLAM®). DECLAM® usually consists of the following components: clear TEDLAR™ polyvinyl fluoride (PVF) film layer for cleanability, silk screen inks for color design, opaque TEDLAR™ PVF film and an embossing layer for texture. Sometimes DECLAM® includes a fiber reinforced layer for extra stability/strength. The processing temperature of decorative laminates should not exceed 100°C.

Sometimes the DECLAM® already incorporates adhesives to support the bonding to the panel. In most of the cases, an additional adhesive, like Bostic 7132, an isocynate activated adhesive, is sprayed onto the contoured panel before DECLAM® is applied. The decorated laminate and the panel are placed in a vacuum forming tool before the whole package is rolled into an IR-oven for the final curing.

The invention as claimed in claim 1 solves the problem of how to shorten the time necessary for forming a contoured shape from a structural panel having a core with synthetic resin facings.

In comparison to thermosets, high performance thermoplastic matrix resins offer not only toughness and low flammability but also the possibility of melting and remelting the resin to accomplish the above-mentioned steps of forming in a one step process.

According to claim 9, the thermoplastic resin faced core structures can be used as intermediate products to form a final decorated product in one step within minutes. The sandwich panels which are used have been made with honeycomb core and thermoplastic face sheets without the use of solvents or extra adhesives for bonding of facesheets and core material. The low fabrication time for shaping and decorating results in saving production costs. Due to the thermoplastic nature of the facings, the shaped panels provide excellent flammability and damage tolerance properties.

Flat composite sandwich panels comprised of facings with high performance fibers, either unidirectional, woven, discontinuous or combinations with a thermoplastic matrix system bonded to a core without the use of an adhesive layer to form the bond between the facesheets and the core, can be formed and decorated with decorative laminate films in a one step operation on conventional presses. The process takes only a few minutes and lower fabrication costs than thermoset technology.

Useful cores are honeycomb structures of aramid paper and foams such as polymethacrylimide and polyetherimide foams or polyvinylchloride, polyurethane and polyisocyanurate foams, and/or combinations of the above.

Combinations of core materials are used for edge trimming and insert applications. Most of the aircraft interior parts with honeycomb core are edge-trimmed (meaning picture framed) with a closed cell foam for sealing of the sandwich as well as for design purposes. Foam inserts in honeycomb structures are used to support local attachments.

Suitable thermoplastic resins for the resin facings include polyesters, polyamides, copolyamides polyolefins and polyetherketoneketone (PEKK) both amorphous and semicrystalline. Polyetheretherketone (PEEK) Stabar™ from ICI, polyetherimide PEI) Ultem™ from G.E. and polyethersulfone (PES) Radel™X from Amoco.

Useful fibers for reinforcing the resin facings are carbon aramid and glass fibers, while the decorative laminate films are selected from polyvinylfluoride films.

Fig. 1 is a schematic illustration representative of the method for shaping and decorating panels.

Fig. 2 is a graph of the compressive strength to failure of an aramid paper honeycomb core material as a function of time and temperature.

Fig. 3 is a graph of the temperature relationship between an aramid paper honeycomb core and the resin facesheet bonded to the core.

Fig. 4 is a schematic illustration partially in a cross section of a contoured shape formed according to this invention.

Fig. 5 is a perspective view of the female mold used in Example 4.

Fig. 5a is a cross sectional view of Fig. 5 taken along line 5a-5a.

In Fig. 1, the apparatus used in the method for forming a contoured shape and decorating the contoured shape is shown to include a high energy heat source 10 (e.g., infrared oven, radiant panels, heated platens, etc.) having upper and lower heating surfaces 12 and 14, respectively, and a press 16 having upper and lower heated platens 18 and 20, respectively. A decorative laminate film 24 is shown laying on the lower heated platen 20 of the press and a resin faced cored panel 26 is shown in "oven" 10.

The forming operation starts with a placement of the panel 26 into oven 10. The panel 26 consists of fiber reinforced thermoplastic resins and honeycomb core, with optional foam inserts and edge-trimming, which are thermally bonded to each other without the use of an adhesive. Fig. 4 is an illustration of a contoured hat-shape composite 30 formed according to this invention. The composite includes a honeycomb core 32 edge trimmed with a foam edging 34. The edge trimmed core fiber reinforced thermoplastic resin facesheets 36, 38 bonded to the core and a decorative film 40 adhered to facesheet 36.

Time and processing temperature are strictly related to the materials which are combined to form the panel. It has been found that high energy heating sources are needed to provide sufficient temperatures to melt the resin of the facesheets without exposing the core materials for too long a time above their maximum processing temperature. The residual compressive strength of the core material is strictly related to its time/temperature history. For example, the compressive strength of the aramid paper honeycomb core, measured by ASTM C365-57, will decrease dramatically above 180°C if the core was exposed for a period of 30 minutes (Fig. 2).

In the case of using high temperature thermoplastic resins, like polyetherketoneketone (PEKK), for the facesheets, it has been found that suitable processing temperatures for the sandwich panels are in the range of 150°-400°C, measured at the facesheets of the panel.

The heater capacity should be optimized so that the facings reach the processing temperatures in less than 240 seconds. In this time frame, the core material works as an insulator (low heat transfer rate) and will not be significantly degraded but will allow better flexibility for the shaping without crushing the cell structures.

Table 1 gives for different heating rates the final corresponded core temperatures, when the processing temperatures for the facesheets (PEKK/Glass 7781) have to be in the range of 250°-350°C. It is obvious that for the shortest heating times the differences the facesheet and core temperatures are the greatest, whereas after 240 seconds to core temperature is only 15-23°C below the facesheet temperature. Heating Time Final Temperature of Face Sheet Final Temperature in the Center of the Core ΔT 30 seconds 250°-350°C 95°-155°C 155°-195°C 60 seconds 250°-350°C 155-250°C 95-100°C 120 seconds 250°-350°C 190°-290°C 60°C 180 seconds 250°-350°C 215°-320°C 30-35°C 240 seconds 250°-350°C 225°C-335°C 15°-25°C
12.7 mm (0.5") honeycomb core; 48 kg/m3 (3 pcf); 3.2 mm (1/8 inch) cell

Glass/7781 reinforced PEKK-lacesheets

One layer of fabric on each side; 40% resin by weight

It has been found that, if these time/temperature relations for core and facesheet material can be achieved across the panel, a one-step forming of compex shaped parts (like stowage bin doors, ceiling or sidewall panels) is possible.

Fig. 3 shows a typical record of the temperature profiles for the facesheets and the center of the aramid paper honeycomb core (48 kg/m3 (3 pcf) honeycomb; 12.7 mm (0.5 inch) thick). After 120 seconds the temperature of the Kevlar™/PEKK facings have reached 260°C whereas the center of the core is at 180°C. At these processing conditions, the panel can be shaped. If higher processing temperatures are required, the facesheets can be heated, for example, up to 300°C. The final core temperature will be increased to 220°C. In this time frame A of 20-25 seconds, called "thermal spiking", the core will not significantly degrade.

Decoration

Normally the high processing temperatures for the thermoplastic facings (e.g., 260°-300°C for PEKK) do not allow the application of DECLAM. This invention, however, describes a one-step process whereby a flat sandwich panel can be postformed and decorated with DECLAM® in one step. The idea is to separate the high heating in the IR-Oven for the facesheets from the low heating of the DECLAM® on top of the mold (Fig. 1). The first step is the heating of the facesheets to processing temperatures of about 150°C to 400°C. Nearly 20 seconds before the panel is moved to the mold, a sheet of decorative laminate 24 cut to the size of the mold is placed on the lower platen 20. The mold has to be in the range of between 75°C and below 150°C. With the DECLAM® clamped in place, the preheated panel is thermoformed in to the final shape in the press 16 at pressures in the range of from about 50 psi to about 90 psi. Immediate cooling under pressure with air and water is essential to achieve adhesion of the DECLAM® to the facings of from about 60 to 1226 N/m (0.3 to 7 pounds per inch) of width.

Example 1

The components of the laminate were laid up in the following manner. Two pieces of amorphous PEKK film were placed on each side of a glass style 7781 fabric to form the facing. The resin content was 40% by weight. Identical facings were layed up on each side of a piece of Nomex™ honeycomb (48 kg/m3 (3 pcf), 6.3 mm (1/4 inch thick), 3.2 mm (1/8 inch) cell) to achieve a sample size of 420 x 420 mm (16.5 x 16.5 inches). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. The panel was then consolidated by heating to about 343°C (650°F) under pressure less than the compressive strength of the core for a time of less than 2-3 minutes and cooling to form a composite structure. The panel was next heated to 260°C, measured at the surface of the facesheets, for 80 seconds in an IR-oven. The oven is designed by Du Pont using quartz lamps of 5 W/cm2 from W Lanchak. The final core temperature in the center was measured at 195°C. After heating the panel is transferred within less than 5 seconds to the mold. Within 20 seconds before removal from the IR-oven, a 420 x 420 mm (16.5 x 16.5) piece of DECLAM® LHR with adhesives HA210 is placed with Kapton™ tape (25.4 mm (1 inch) wide) on the bottom portion of the mold. The mold temperature was set at 100°C. The parabolic mold has a radius of 15.2 cm (6 inches) and a depth of 32 mm (1.26 inches) (Fig. 5). During forming a constant pressure of 600 kPa (87 psi) was applied. Immediately after forming, on a Shuler 100 tons hydraulic press, the mold was cooled with both air and water for 1.5 minutes to 30°C.

Four 2.5 x 15 cm (1 x 6 inch) strips were cut along the perimeter of the parabolic panel. The samples were tested on an 1125 Instron machine using hydraulic clamps (pressure of 551 kPa (80 psi)) and a crosshead speed of 30.5 cm (12 inches) per minute. To test for DECLAM® adhesion the bottom honeycomb structure was placed in hydraulic clamps. The DECLAM® was initially started with a 12.7 mm (0.5 inch) tab. This was placed in the top clamp. The average peel strength of the decorative laminate to the facesheet of the samples was about 260 N/m (1.49 pounds per inch) width as measured by the method for measuring ply adhesion according to ASTM D82554.

A comparative thermoset laminate was laid up in this manner. Two pieces of glass/phenolic prepreg Type 6209-18-2 from Ciba Geigy with a resin content of 40% by weight (area weight of 302 g/m2 (8.9 ounces per square yard)) were placed on each side of Nomex™ honeycomb (48 kg/m3 (3 pcf), 6.3 mm (1/4 inch) thick, 3.2 mm (1/8 inch) cell). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. This hand laid-up was placed on top of the parabolic mold. The mold temperature was set to 100°C. They lay-up was cured at 537 kPa (78 psi) for 90 minutes. After opening the mold, a piece of 420 x 420 mm (16.5 x 16.5 inch) DECLAM®, same as above, was applied to the bottom mold. At 100°C the part and the DECLAM® were bonded by 551 kPa (80 psi) pressure for an additional 5 minutes.

The panels were cut and tested in the same manner as the thermoplastic panels above. The average peel strength was about 58 N/m (0.33 pounds per inch) width as measured by ASTM D-82554. Therefore, the one-step thermoplastic DECLAM® product shows a comparatively higher peel adhesion of the decorative laminates by a factor of 4.6.

It is important to recognize the peel adhesion of the DECLAM® and thermoplastic facesheet of about 260 N/m (1.49 pounds per inch) width is lower than the adhesion between core and facesheets. This will aid in the replacement of the DECLAM® without costly replacement to the panel itself. This will help should retrofitting be needed based on new interior design. Should this occur, a new piece of DECLAM® can be welded onto already existing thermoplastic panels. This will be another cost saving device over thermosets.

Along with better adhesion, a tremendous reduction in processing time for shaping and decorating (3 minutes to 5 minutes for thermoplastic configuration vs. 60 to 100 minutes for the thermoset) leads to lower manufacturing cost.

Example 2

The components of the laminate were laid up in the following manner. Two pieces of amorphous PEKK film were placed on each side of a Kevlar™ fabric 285 (from Clark Schwebel) to form the facing. The resin content was 50% by weight. Identical facings were placed on each side of a piece of Nomex™ honeycomb (48 kg/m3 (3 pcf), 12.7 mm (1/2 inch) thick, 3.2 mm (1/8 inch) cell) to achieve a sample size of 420 x 420 mm (16.5 x 16.5 inches). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. The panel was then consolidated as described in Example 1.

The panel was next heated to 260°C for 80 seconds in an IR-oven. The oven was designed by Du Pont using quartz lamps of 5 W/cm2 from W. Lanchak. The final temperature of the core was measured in the center at 195°C. After heating, the panel is transferred within 5 seconds to the mold. Within 20 seconds before removal from the IR-oven, a 420 x 420 mm (16.5 x 16.5) piece of DECLAM® LHR with adhesive HA210 is placed with Kapton™ tape (25.4 mm (1 inch) wide) on the bottom portion of the mold The mold temperature was set at 100°C. The parabolic mold (Fig. 5) has a radius of 15.2 cm (6 inches) and a depth 32 mm (1.26 inches). During forming a constant pressure of 565 kPa (82 psi) was applied. Immediately after forming, on a Shuler 100 ton hydraulic press, the part was cooled with both air and water for 2 minutes to 30°C.

Four 2.5 x 15 cm (1 x 6 inch) strips were cut along the perimeter of the parabolic panel. The samples were tested on an 1125 Instron machine using hydraulic clamps (pressure of 552 kPa (80 psi)) and a crosshead speed of 30.5 cm (12 inches) per minutes. To test for DECLAM® adhesion the bottom honeycomb structure was placed in hydraulic clamps. The DECLAM® was initially started with a 12.7 mm (0.5 inch) tab. This was placed in the top clamp. The average peel strength of the DECLAM to the facesheet of the samples was about 370 N/m (2.11 pounds per inch) width (ASTM D82554).

A comparative thermoset laminate was laid up in this manner. Two pieces of Kevlar™/phenolic prepreg Type 6209-181 from Ciba Geigy with a resin content of 50% by weight (area weight 173 g/m2 (5.1 ounces/square yard)) were placed on each side of Nomex™ honeycomb (48 g/m3 (3 pcf, 12.7 mm (1/2 inch) thick, 3.2 mm (1/8 inch) cell). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. This hand laid-up was placed on top of the parabolic mold. The mold temperature was set to 100°C. The lay-up was cured at 552 kPa (80 psi) for 90 minutes. After opening the mold a piece of 420 x 420 mm (16.5 x 16.5 inch) DECLAM® was applied to the bottom mold. At 100°C and the DECLAM® were bonded by 552 kPa (80 psi) pressure for an additional 5 minutes.

The panels were cut and tested in the same manner as the thermoplastic panels above. The average peel strength was about 99.8 N/m (0.57 pound per inch) width (ASTM D82554). Therefore, the one-step thermoplastic DECLAM® product shows a comparatively higher peel adhesion of the decorative laminates by a factor of 3.7.

Along with better adhesion, a tremendous reduction in processing time for shaping and decorating (3 minutes to 5 minutes for thermoplastic configuration vs. 60 to 100 minutes for the thermoset) leads to lower manufacturing cost.

Example 3

The components of the laminate were laid up in the following manner. Two pieces of amorphous PEKK film were placed on each side of a Kevlar™ 285 to form the facing. The resin content was 50% by weight. Identical facings were placed on each side of a piece of 15 x 28 cm (6" x 11") Nomex™ honeycomb (48 kg/m3 (3 pcf, 12.7 mm (1/2 inch thick), 3.2 mm (1/8 inch) cell) surrounded by a picture frame of Rohacell™ WF200 foam (12.7 mm (1/2 inch thick, 38 mm (1.5 inch) wide) for edge-trimming (Fig. 6). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. The panel was then consolidated according to Example 1

The panel was next heated to 300°C for 80 seconds in an IR-oven. The oven was designed by Du Pont using quartz lamps of 5 W/cm2 from W. Lanchak. The final temperature of the core was measured in the center at 220°C. After heating the panel is transferred within less than 5 seconds to a hat-shaped mold to form a part similar to that described in Fig. 4. Within in 20 seconds before removal from the IR-oven, a 15 x 28 cm (6" x 11") piece of DECLAM® LHR with the adhesive HA211 is placed with Kapton™ tape (25,4 mm (1 inch) wide) on the bottom portion of the mold. The mold temperature was set at 100°C. During forming a constant pressure of 565 kPa (82 psi) was applied. Immediately after forming, on a Shuler 100 ton hydraulic press, the mold was cooled with both air and water for 2 minutes to 30°C. Both honeycomb core andedge-trimmed foam were formed very uniformly.

Example 4

The components of the laminate were layed up in the following manner. Two pieces of amorphous PEKK film (150 MI as measured by ASTM-1238/79 procedures) were placed on each side of a Kevlar™ fabric 285 (from Clark Schwebel) to form the facing. The resin content was 50% by weight. Identical facings were placed on each side of a piece of Nomex™ honeycomb (48 kg/m3 (3 pcf), 6.3 mm (1/4 inch) thick, 3.2 mm (1/8 inch) cell) to achieve a sample size of 420 x 420 mm of (16.5 x 16.5 inches). The warp direction of the fabric was aligned perpendicular with the ribbon direction of the core. The panel was consolidated according to Example 1.

The consolidated panel was then placed on a handling mechanism which transfers into the IR-oven. The oven was designed by Du Pont using quartz lamps of 5 W/cm2 from W. Lanchak. The panel was heated to 260°C for 80 seconds with a heater capacity of 70%. The final temperature of the core was measured in the center at 195°C. After heating the panel is transferred via the handling mechanism within less than 5 seconds to the mold. A 420 x 420 mm (16.5 x 16.5 inch) piece of Kevlar™ spun-bonded material was then placed on the bottom of the parabolic mold (Fig. 5) to create an embossed effect to the panel surface. Within 20 seconds before removal, the preheate panel from the IR-oven a 420 x 420 mm (16.5 x 16.5) piece of DECLAM® is placed with Kapton™ tape (25.4 mm (1 inch) wide) was positioned on the bottom portion of the mold on top of the spun-bonded Kevlar™ fabric. The mold temperature was set at 100°C. The parabolic mold has a radius R of 15.2 cm (6 inches) and a depth C of 32 mm (1.26 inches).

During forming, on the Shuler 100 ton hydraulic press, a constant pressure of 620 kPa (92 psi) was applied. Immediately after forming the mold was cooled with both air and water for 2 minutes to 30°C. The addition of the spun-bonded Kelvar™ fabric will reduce intensive shine that can occur on the decorative polyvinylflouride materials. This spun-bonded fabric will also create an embossed effect to the panel surface. With mold temperatures between 75°C and 150°C the spun-bonded fabric can be easily removed from the decorative surface.

Four 2.5 x 15.2 cm (1" x 6") strips were cut along the perimeter of the parabolic panel. The samples were tested on an 1125 Instron machine using hydraulic clamps (pressure of 552 kPa (80 psi)), and a crosshead speed of 30.5 cm/min (12 inch/minute). To test for DECLAM® adhesion the bottom honeycomb structure was placed in hydraulic clamps. The DECLAM® was initially started with 12.7 mm (0.5 inch) tab. This was placed in the top clamp. The average peel strength of the DECLAM® to the facesheet of the samples was about 426 N/m (2.43 lbs per inch) width.


Anspruch[de]
  1. Verfahren zum Formen einer Tafel (26) zu einem Bauteil, wobei die Tafel (26) aus einem Kernelement (32) und einer Deckschicht (36, 38) aus faserverstärktem Kunstharzbahnmaterial gebildet ist, die an wenigstens eine Seite des Kernelements (32) gebunden ist, wobei auf der Deckschicht (36, 38) eine dekorative Folie haftet, enthaltend
    • Erhitzen der Tafel (26);
    • Anordnen der erhitzten Tafel (26) in einer Form (16), die die Gestalt des Bauteils hat;
    • Binden einer Polyvinylfluoridfolie (24) an die mit dem Kernelement verbundene thermoplastische Deckschicht;
    • Pressen der in der Form (16) befindlichen Tafel (26) zur Bildung eines Bauteils; und
    • Kühlen des Bauteils;
    dadurch gekennzeichnet,
    • daß die Deckschicht (36, 38) ein faserverstärktes Kunstharzbahnmaterial enthält und
    • daß der Erhitzungsschritt das Erhitzen der Deckschicht (36, 38) auf eine Temperatur im Bereich von ungefähr 150 °C bis ungefähr 400 °C im Bereich von ungefähr 30 sec bis ungefähr 240 sec enthält bei Aufrechterhaltung der Temperatur des Kerns (32) im Bereich von ungefähr 95 °C bis ungefähr 335 °C.
  2. Verfahren nach Anspruch 1, enthaltend den Schritt des Erhitzens der Form auf eine Temperatur im Bereich von ungefähr 75 °C bis ungefähr 150 °C vor dem Anordnen der erhitzten Tafel (26) in der Form (16).
  3. Verfahren nach Anspruch 1 oder 2, wobei das faserverstärkte thermoplastische Harz mit Glasfasern verstärktes Polyetherketonketon und der Kern (32) eine Wabenstruktur aus Aramidpapier sind.
  4. Verfahren nach Anspruch 1 oder 2, wobei das faserverstärkte thermoplastische Harz mit Kohlenstoffasern verstärktes Polyetherketonketon und der Kern (32) eine Wabenstruktur aus Aramidpapier sind.
  5. Verfahren nach Anspruch 1 oder 2, wobei das faserverstärkte thermoplastische Harz mit Aramidfasern verstärktes Polyetherketonketon und der Kern (32) eine Wabenstruktur aus Aramidpapier sind.
  6. Verfahren nach Anspruch 1 oder 2, wobei das Kernelement (32) eine Wabenstruktur aus Aramidpapier ist und die Wabenstruktur mit Schaum (34) eingefaßte Ränder hat.
  7. Verfahren nach Anspruch 1, wobei die Deckschicht (36, 38) in 80 sec auf 260 °C erhitzt und die Kerntemperatur unter 195 °C gehalten wird.
  8. Verfahren nach Anspruch 1, wobei die Deckschicht (36, 38) in 80 sec auf 300 °C erhitzt und die Kerntemperatur unter 220 °C gehalten wird.
  9. Verfahren nach einem der Ansprüche 1 bis 8, wobei eine Bahn aus der Polyvinylfluoridfolie (24) in einem gesonderten Schritt auf eine Temperatur von ungefähr 75 °C bis ungefähr 150 °C erhitzt und die Tafel (26) in Deckung mit der erhitzten Bahn aus Polyvinyifluoridfolie in der Form (16) angeordnet wird.
  10. Verfahren nach Anspruch 9, wobei die erhitzte Tafel (26) und die erhitzte Folie (24) bei einem Druck von ungefähr 345 (50) bis ungefähr 620 kPa (90 psi) zusammengepreßt werden.
  11. Verbundstruktur, enthaltend einen Wabenkern (32), mit dessen einer seiner Seiten eine Deckschicht (36, 38) verbunden ist, die ein faserverstärktes thermoplastisches Harz und eine haftende dekorative Auflage (40) aus Polyvinylfluorid enthält.
  12. Verbundstruktur nach Anspruch 11, wobei die dekorative Auflage (40) ein Haftvermögen von 52 bis 1226 N/m (0,3 bis 7 pounds per inch) Breite hat.
Anspruch[en]
  1. A method for shaping into a structural part of a panel (26) formed of a core member (32) and a fiber reinforced synthetic resin sheet material facing (36, 38) bonded to at least one side of the core member (32) with a decorative film adhered to the facing (36, 38), said method comprising:
    • heating said panel (26);
    • placing the heated panel (26) in a mold (16) configured to said structural part;
    • bonding a polyvinyl fluoride film (24) to the thermoplastic facing bonded to the core member;
    • pressing said panel (26) in said mold (16) to form said structural part; and
    • cooling said structural part;

         characterized
    • in that said facing (36, 38) contains a fiber reinforced thermoplastic resin sheet material and
    • in that said heating step includes heating said facing (36, 38) to a temperature in the range of from about 150°C to about 400°C within the range of from about 30 seconds to about 240 seconds while maintaining the temperature of the core (32) in the range of from about 95°C to about 335°C.
  2. The method of claim 1, including the step of heating said mold to a temperature in the range of from about 75°C to about 150°C prior to placing said heated panel (26) in said mold (16).
  3. The method of claim 1 or 2 wherein said fiber reinforced thermoplastic resin is polyetherketoneketone reinforced with glass fibers, said core (32) being a honeycomb structure of aramid paper.
  4. The method of claim 1 or 2 wherein said fiber reinforced thermoplastic resin is polyetherketoneketone reinforced with carbon fibers, said core (32) being a honeycomb structure of aramid paper.
  5. The method of claim 1 or 2 wherein said fiber reinforced thermoplastic resin is polyetherketoneketone reinforced with aramid fibers, said core (32) being a honeycomb structure of aramid paper.
  6. The method of claim 1 or 2 wherein said core member (32) is a honeycomb structure of aramid paper, said honeycomb structure having edges trimmed with foam (34).
  7. The method as defined in claim 1 wherein said facing (36, 38) is heated to 260°C within 80 seconds, said core temperature being maintained below 195°C.
  8. The method as defined in claim 1 wherein said facing (36, 38) is heated to 300°C within 80 seconds, said core temperature being maintained below 220°C.
  9. The method as defined in any one of claims 1 to 8 wherein a sheet of said polyvinyl fluoride film (24) is heated in a separate step to a temperature of from about 75°C to about 150°C and said panel (26) is placed in registry with said heated sheet of polyvinyl fluoride film in said mold (16).
  10. The method of claim 9 wherein the heated panel (26) and heated film (24) are pressed together at a pressure of from about 345 (50) to about 620 kPa (90 psi).
  11. A composite structure comprising a honeycomb core (32) having bonded to one of its faces a facesheet (36, 38) comprising fiber reinforced thermoplastic resin and an adhered decorative polyvinyl fluoride overlayer (40).
  12. The composite structure of claim 11, said decorative overlayer (40) having a peel adhesion of from 52 to 1226 Newtons per meter (0.3 to 7 pounds per inch) of width.
Anspruch[fr]
  1. Un procédé de conformation en élément de construction d'un panneau (26) formé d'un noyau 32 et de surfaces en feuille de résine synthétique (36,38) renforcées par des fibres et collées sur au moins l'une des faces du noyau (32), avec un film décoratif adhérant aux surfaces (36,38), ledit procédé comprenant les étapes suivantes :
    • chauffage dudit panneau 26;
    • introduction du panneau 26 chauffé dans un moule 16 auquel on a donné la configuration dudit élément de construction;
    • collage d'un film de fluorure de polyvinyle 24 sur la surface thermoplastique collée sur le noyau;
    • compression dudit panneau 26 dans ledit moule 16 pour former ledit élément de construction; et
    • refroidissement dudit élément de construction;
    caractérisé
    • en ce que ladite surface 36,38 contient un matériau en feuille de résine thermoplastique renforcée par des fibres et
    • en ce que ladite étape de chauffage comprend le chauffage de ladite surface 36,38 à des températures comprises entre environ 150°C et environ 400°C pendant une durée comprise entre environ 30 et environ 240 secondes, le noyau étant maintenu à une température comprise entre environ 95°C et environ 335°C.
  2. Le procédé selon la revendication 1, comprenant l'étape de chauffage dudit moule à une température d'environ 75°C à environ 150°C avant l'introduction dudit panneau 26 chauffé dans ledit moule 16.
  3. Le procédé selon la revendication 1 ou 2 dans lequel ladite résine thermoplastique renforcée par des fibres est une polyéthercétonecétone renforcée par des fibres de verre, ledit noyau 32 étant une structure alvéolaire en papier d'aramide.
  4. Le procédé selon la revendication 1 ou 2 dans lequel ladite résine thermoplastique renforcée par des fibres est une polyéthercétonecétone renforcée par des fibres de carbone, ledit noyau 32 étant une structure alvéolaire en papier d'aramide.
  5. Le procédé selon la revendication 1 ou 2 dans lequel ladite résine thermoplastique renforcée par des fibres est une polyéthercétonecétone renforcée par des fibres d'aramide, ledit noyau 32 étant une structure en nid d'abeilles en papier d'aramide.
  6. Le procédé selon la revendication 1 ou 2 dans lequel ledit noyau 32 est une structure en nid d'abeilles en papier d'aramide, ladite structure en nid d'abeilles étant délimitée par des bordures en mousse 34.
  7. Le procédé selon la revendication 1 dans lequel ladite surface 36,38 est chauffée à 260°C en 80 secondes, la température dudit noyau étant maintenue inférieure à 220°C.
  8. Le procédé selon la revendication 1 dans lequel ladite surface 36,38 est chauffée à 300°C en 80 secondes, la température dudit noyau étant maintenue inférieure à 220°C.
  9. Le procédé selon l'une quelconque des revendications 1 à 8 dans lequel une feuille dudit film de fluorure de polyvinyle 24 est chauffée dans une étape séparée à une température d'environ 75°C à environ 150°C et ledit panneau 26 est introduit en correspondance avec ladite feuille chauffée du film de fluorure de polyvinyle dans ledit moule 16.
  10. Le procédé selon la revendication 9 dans lequel le panneau chauffé 26 et le film chauffé 24 sont comprimés ensemble sous une pression d'environ 345 (50) à environ 620 kPa (90 psi).
  11. Une structure composite comprenant un noyau 32 alvéolaire sur l'une des faces duquel est collé un film superficiel 36,38 comprenant une résine thermoplastique renforcée par des fibres et, y adhérant, une couche supérieure décorative 40 en fluorure de polyvinyle.
  12. La structure composite selon la revendication 11 dans laquelle la couche supérieure décorative 40 présente une adhérence au pelage de 52 à 1226 Newtons par mètre (0,3 à 7 livres par pouce) de largeur.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

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