JPH06503522A - Process for the preparation of thermoplastic honeycomb sandwich structures - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Process for the preparation of thermoplastic honeycomb sandwich structures Background of the invention field of invention The present invention allows surface notes or skins to be quickly and cost-effectively fiber-reinforced or non-fiber-reinforced. Concerning the preparation of honeycomb sandwich structures as applied to reinforced thermoplastic honeycombs .

Description of related technology Honeycomb panels require an exceptionally lightweight rigid planar or moderately curved structure. , used in the transportation and aerospace industries. In the past, honeycombs of , the fiber reinforcement was impregnated with thermosetting resin and the honeycomb was laid up by hand. More prepared. − Cubic feed honeycombs are often It took over 24 hours. Recently, fiber-reinforced and non-reinforced thermoplastic honeycombs have also been , has been used, but until now, its production has been time and labor intensive. same In currently pending application no. 071531.184, for the production of thermoplastic honeycombs. A continuous method of increasing the use of these structural elements is disclosed.

Following the production of honeycomb by either method, a finished core is produced with a flat surface of the required thickness. A thermosetting film that is cut or slit into segments and then heat cured. Luminous adhesives, such as bismaleimide or epoxy resins, are commonly used in fiber-reinforced plastics. A laminate is used to bond the skin, which may be a preg or laminate, to the core. Menshi The core assembly with adhesive and film adhesive is heated while pressure is applied to the assembly. It will be done. Following a curing time, typically several hours, honeycomb sandwich panels are cured as intended. cut to the appropriate size for the application.

The process of bonding the honeycomb to the face sheet as performed by prior art processes The process uses time-consuming and relatively expensive film adhesives, and their adhesive strength Viscosity and curing cycles often must be adjusted for each specific application. stomach.

Purpose of invention The thermoplastic honeycomb core may have been previously bonded to the face sheet or, preferably, separated by a separation element. be bonded to the face sheet by the use of a thermoplastic film supplied as a blank; was discovered unexpectedly. This process makes it relatively cheap and easy to use. A thermoplastic film is used and the cycle time for bonding is several hours. reduced to just a few seconds.

Brief description of the drawing Figure 1 shows a honeycomb core bonded to a face sheet with a thermoplastic bonding film bonded to it. FIG.

Figure 2 shows a honeycomb bonded to a face sheet using a separate thermoplastic bonding film. It is a side view of Mukoa.

FIG. 3 is a side view of a process using a radiant heat bank and platen.

FIG. 4 is a top view of the process illustrated by FIG.

Description of preferred embodiments The thermoplastic honeycomb used in the process of the invention is 30% by weight fact, including those prepared from resin systems containing small amounts of thermosetting resins, without overlapping above, in any format. Thermoplastic materials used include, but are not limited to: polyethylene, polypropylene, polyoxymethylene, polyarylene ether, polyetherketone, polysulfone, polyethersulfone, polyamide, poly Aramid, polybenzimidazole, polyimide, thermoplastic polyurethane, etc. be. As a small part of thermosetting resin, for example, bismaleimide resin, epoxy resin, ananate resin, isocyanate resin, thermosetting polyimide, etc. It will be done.

Thermoplastic honeycombs are reinforced with fiber reinforcement. The reinforcement material is spunbonded fiber. optionally sewn and/or sized runs to provide security and integrity. Forms of dam continuous or chopped fibers, woven fabrics, unidirectional tapes or combinations thereof It is. The fibers used include glass, quartz, carbon (carbon/graphite), boron nitride, prepared from inorganic fibers such as silicon carbide, ceramics, or the aforementioned thermoplastics. There are organic synthetic fibers such as

The face sheet can be made of metal, fiber-reinforced thermosetting resin or thermoplastic, or unreinforced thermoplastic. It is a sexual substance. The face sheet and honeycomb core are bonded to a thermoplastic bonding film. I can do it. Preferably used in honeycomb, face sheet and bonding film The thermoplastics used are the same.

Thermoplastic films must be compatible with the materials being joined.

Preferably, as mentioned above, the thermoplastic film is the same thermoplastic as the honeycomb material. It is quality. Compatibility determines the force required to remove the skin from the honeycomb It is evaluated by The thickness of the film varies widely, but the preferred thickness is about 0 ．． 05mm~1. Qmm, more preferably in contact with or non-fused with the face sheet. If it is compatible, it will be glued. Furthermore, a separate filament that is fusion welded or glued to the skin Instead of a lume, a strip containing enough thermoplastic material can be fused to the honeycomb. It is within the spirit of the invention to use Kin. Such skins also It can be considered as an illum/skin unit. The object of the present invention is to connect the skin to the core. Avoid the use of thermosets completely when combining, but less than about 10 weight percent The use of thermoplastic bonding films containing small, limited amounts of thermosetting resins is , still within the spirit of the invention. Such films are fully thermoplastic as well as It is expected that it will work.

In the process of invention, the bonding film is a face sheet or as it is often called. For example, the application of infrared radiation or hot gas jets, regardless of whether the skin has been previously attached to It is heated to its melting point by thermal means, placed on a honeycomb, and pressed onto it. By combining various components. The latent heat of melting of thermoplastics is in order to melt the thermoplastic and fuse it to the bonding film and face sheet. It is enough. Often the latent heat of fusion is sufficiently high that cold air blast or water or Cooling of the assembly with other liquids is required. Thermoplastic film up to melting temperature Instead of heating, the film may be melt extruded at the bond point.

In Figure 1, the honeycomb (1) has been previously fused or glued to the skin (2). A composite thermoplastic film (3) is used to overlay the skin (2). From source (4) Infrared radiation is used to heat the film (3) to melting temperature. The bond is , carried out by a pressure roller (5) and optionally cooled by a water jet (6) Ru. Instead of pressure rollers, the assembly can be pressurized using a standard puller brace. Also good. The platen surface is generally cooled to remove thermal sag and prevent core overheating. Prevents skin blooming.

Figure 2 shows a preferred method of bonding the skin to the honeycomb. The numbering is this except that the film is a separate thermoplastic film that is not prebonded to the skin. As shown in FIG.

FIG. 3 is a side view of one embodiment of the process. Honeycomb core (1) has pressure It is guided by guide rails (2) in the area between the platens (9, 10). Upward The skin (3) and the lower skin (4) are connected to the upper film layer (5) and the lower film layer, respectively. It is bonded to the honeycomb (1) using a film layer (6). The film layer is infrared rays heated by the heating banks (7, 8), the platen is closed and the pressure is It is maintained until it cools down. Cooling can be achieved by water spray or air onto or into the platen (not shown). Facilitated by air collision.

FIG. 4 is a view of the process of FIG. 3 from the top. The honeycomb core (1) is The process between the upper and lower platens (9, 10 (only the top platen shown)) move along the space guide rail (2). The upper and lower adhesive films (5, 6) are , by upper and lower infrared heating banks (7, 8 (only upper bank shown)). platen between the honeycomb (1) and the upper and lower skins (3, 4). The upper and lower skins ( 3, 4) are also folded back into the platen area along guide rails. press is closed and pressure is maintained below the melting temperature of the thermoplastic adhesive. Ru. final overlay), the q-nicum product emerges in (11) and the process is repeated. It will be done.

Example 1 Measures 30cm by 30cm and is made of Tyvek spunbond polyolefin The 19mm thick core is made of glass fiber polyester supplied by Azdel, Inc. It was bonded to two 1.8 mm skins of propylene impregnated mat. The bonding film , 0.50mm polypropylene film and ceramic infrared radiant heating element heated to melting point. The total time to assemble the honeycomb sand inch is 1 5 seconds, of which 5 seconds are used to heat the polypropylene film. 5 seconds are used to pressure bond the assembly, the pressure is applied to the platen and the pressure applied by a roller. Minimum pressure is required for bonding, and pressure are kept until cool and cooled by spraying water on the sandwich for 5 seconds. It was.

Example 2 The process of Example 1 was performed using glass fibers impregnated with polyether sulfone. A core of 0.38 mm polyethersulfone impregnated glass fiber is sorted or skimmed. It was repeated using The bonding film used is polyetherimide thermoplastic It was a 0.13 mm film of high quality (ULTEM). Total join time is the same as before It was 15 seconds.

Example 3 Example 2 was repeated but the heat was applied to the platen heated to 350°C on the cold core. Supplied externally to the face sheet. Immediately after bonding, the assembly is heated under pressure with a water jet. The fog ring was cooled down. The total time to produce the final sandwich is approximately 510 It was seconds.

+1111111111111111111 Copy and translation of amendment) Submission form ( Patent Law Article 184-8) June 2, 1993

Claims (4)

[Claims] 1. Adheres one or more skins to thermoplastic honeycomb without the use of thermosetting adhesives In the process for the preparation of honeycomb sandwich materials by letting , (a) positioning the thermoplastic honeycomb adjacent to but spaced apart from the skins to be joined; And, (b) positioning a thermoplastic film between the honeycomb and the skin to be joined; , (c) heating the thermoplastic film to a melting temperature; and (d) heating the honeycomb. and applying pressure in an amount sufficient to fuse the skin. Roces. 2. Claim 1, wherein the thermoplastic film of step (b) is integral with the skin. process. 3. (e) cooling honeycomb/skin products obtained by air or liquid flow; 3. The process according to claim 1 or 2, further comprising: 4. Claim 1, wherein the heating of the thermoplastic film (c) is achieved using radiant heat. , 2 or 3.