WO1999038683A1 - Panneaux composites a revetement de classe a - Google Patents

Panneaux composites a revetement de classe a Download PDF

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Publication number
WO1999038683A1
WO1999038683A1 PCT/US1999/001710 US9901710W WO9938683A1 WO 1999038683 A1 WO1999038683 A1 WO 1999038683A1 US 9901710 W US9901710 W US 9901710W WO 9938683 A1 WO9938683 A1 WO 9938683A1
Authority
WO
WIPO (PCT)
Prior art keywords
veil
layer
class
panel
consolidating
Prior art date
Application number
PCT/US1999/001710
Other languages
English (en)
Inventor
Gerald Warren Minato
Mark David Thiede-Smet
Brian Curtis Roundtree
Jon Petter Bakken
Blaine Mattison
Richard Matt Okarski
Original Assignee
Hexcel Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hexcel Corporation filed Critical Hexcel Corporation
Publication of WO1999038683A1 publication Critical patent/WO1999038683A1/fr

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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
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/28—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer impregnated with or embedded in a plastic substance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/08—Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
    • B29C70/086—Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers and with one or more layers of pure plastics material, e.g. foam layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
    • B29C70/34—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation
    • B29C70/345—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation using matched moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/545—Perforating, cutting or machining during or after moulding
    • 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
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/0007—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding involving treatment or provisions in order to avoid deformation or air inclusion, e.g. to improve surface quality
    • 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
    • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
    • B32B2309/60—In a particular environment
    • B32B2309/68—Vacuum

Definitions

  • the invention relates to laminated composite panels made up of layers of reinforcement in a resin matrix, that have a "Class A" surface so that they may be used in a variety of applications including contoured panels in automobiles, aircraft, and the like.
  • the invention provides lightweight structural panels with Class A surfaces, and methods for producing these panels.
  • the panels are suitable for use in vehicles, such as automobiles, trucks, boats, railway cars, and the like, where it is desired to have a lightweight structural panel with a cosmetically smooth surface to which a paint can be tightly adhered.
  • the laminated panels of the invention can be made in a range of thicknesses and strengths to accommodate a wide variety of applications. Moreover, proper selection of laminate components, in particular the proportion and type of reinforcement, eliminates the need for stiffeners on undersurfaces of the panels, for most applications.
  • the panel laminate structure has several layers. Proceeding sequentially from the Class A surface, a first layer underlies the surface. This layer is either a film, or a veil. Generally, when the layer is a film, it overlies the veil, which is the second layer. In certain embodiments, the film is not needed, and the veil is the first layer. In certain other embodiments, the veil is not required.
  • This veil which assists in preventing print-through of underlying reinforcement, is of a type that is drapeable over a contoured surface, before it is consolidated into the laminate. Moreover, the veil is comprised of non-woven fibers and, before consolidation, it is able to absorb liquid resin.
  • the central layer of the laminate is a core of a material that is compressible, before consolidation.
  • the optional film which overlies the veil may be selected from “dry films” and “wet films,” as defined herein. The film reduces pin-holing of the laminate's surface, improves paint adhesion, and reduces the amount of release agent needed in the mold in the laminate consolidation process.
  • the dry films are selected from commercially available sheets of thermoplastic or thermosetting polymer or composite. The wet films are gelcoats applied to the mold surface, matched to the resin matrix.
  • the preferred laminate is symmetrical in the sense that layers on each side are duplicated on the other side, except for the veil (and film, if one is present) which is only on the side(s) requiring a Class A finish.
  • the veil, reinforcing layers, and the central core are embedded in a resinous matrix that also forms the Class A surface.
  • the matrix is a mixture of a thermosetting resin and optionally a relatively high proportion of an organic and/or inorganic filler, or mixture of fillers.
  • these fillers in combination with the veil layer, play an important role in preventing print- through of the underlying reinforcing layers of the composite on the panel surface. This facilitates the forming of a smooth Class A surface.
  • the structural panels of the invention may be prepared with a resin matrix selected from any one or more of a wide variety of thermosetting resins.
  • thermosetting resins include epoxy resins, phenolic resins, polyester, vinyl ester, polyvinyl ester, polyimide, modified acrylic, polyurethane, bismaleimide, and the like, and hybrids of these.
  • the composite in another aspect of the composite panels of the invention, includes a high proportion of reinforcing fiber, which provides an improved strength to thickness ratio relative to prior art composite panels.
  • stiffeners are not needed to make panels suited for automotive applications.
  • the reinforcing layers of the laminated panels be located as near to the outer surfaces of the laminate as possible for maximum strength and stiffness.
  • the invention also provides methods of making the laminated structural panels.
  • the method includes sequentially laying down each layer and wetting the layer with liquid resin before laying down the next layer.
  • the core layer if one is used, may not be wetted.
  • the last reinforcing layer underlying the veil has a unidirectional ply.
  • a resin mixture preferably including a relatively high proportion of opaque filler, is applied to the last reinforcement layer laid down .
  • a drapeable veil is laid down over the resin- wetted last reinforcement layer, and the resin mixture is then applied over the veil.
  • a film is then laid down over the wetted veil.
  • the final layer added, whether veil or film, faces the surface where the Class A surface will be formed after consolidation.
  • Consolidation under heat and pressure produces a structural panel with a Class A surface on the side adjacent the veil (or optional film).
  • this Class A surface is achieved directly through consolidation, and without further surface modifying treatment, such as abrasion, blasting (using particulates or water), surface filling, or another technique.
  • surface modifying treatment such as abrasion, blasting (using particulates or water), surface filling, or another technique.
  • all the reinforcing layers and central core layer to be consolidated are laid down, with the veil (or film) as the topmost layer. Then a resin mixture, preferably including a relatively high proportion of opaque filler, is applied before consolidation.
  • the invention also provides a "stratified cure" method of regulating the relative gellation or cure sequence of resin- wetted layers during consolidation of a composite panel which results in production out-of-mold of a composite laminate panel with a Class-A surface.
  • the rate of cure of a resin is accomplished by a selection of cure agents, or adjusting the reactivity of the resin before application to a specific layer of the layup construction to be consolidated.
  • the less reactive layers will remain more moldable to fill any surface or interlaminar deviations that may arise after the layers wetting with the more reactive resin have gelled or cured. Resins with varying characteristics can be used in any panel layer.
  • Controlling resin reactivity and cure rate can also be accomplished by varying the temperatures of the press molds (dies). For example if there are two mold halves of different temperatures, the hotter mold half will accelerate the resin cure rate closest to its surface while the cooler mold surface will impede the resin cure rate adjacent to its surface. For press molds with two halves, the preferred temperature difference range is from 10 - 55°C.
  • the resin matrix may include several additives, including electrical conductors, and resin charge modifiers.
  • the resin contains additives that dissipate any electrical charge after a panel has been cured to facilitate the adhesion of paint to the consolidated panel.
  • FIGURE 1 is a schematic end view of a panel, with layers exploded for ease of description, in accordance with the invention
  • FIGURE 2 is an end view of an alternative embodiment of a panel in accordance with the invention, with layers exploded for ease of description;
  • FIGURE 3 is a simplified process flow diagram illustrating process steps in an embodiment of the method of the invention;
  • FIGURE 4 is a schematic cross section through an edge of a mold for forming panels showing a seal for drawing a vacuum on the mold and a peripheral knife edge to size the panels;
  • FIGURE 5 is a schematic cross section through an edge of a mold containing layers for consolidating into a laminate, showing knife edges for cutting laminates to size;
  • FIGURE 6 is a schematic exploded end view of a structural panel constructed in accordance with the present invention
  • FIGURE 7 is an environmental view of a press used to construct a structural panel in accordance with the present invention, with the press shown in cross section for clarity;
  • FIGURE 8 is a cross-sectional end view of a press used to construct a structural panel in accordance with the present invention, with the press shown in the open position;
  • FIGURE 9 is a cross-sectional end view of a press used to construct a structural panel in accordance with the present invention, with the press shown in the partially closed position;
  • FIGURE 10 is a cross-sectional end view of a press used to construct a structural panel in accordance with the present invention, with the press shown in the compressed position.
  • structural panels and methods of making these panels, that have a Class A surface finish on at least one side.
  • the surface finish is obtained directly out-of-mold without requiring subsequent abrasive surface modifying treatments or surface filling techniques.
  • the structural panels are significantly stronger (i.e., higher strength to thickness ratio, flexural modulus) than panels previously made in the automotive industry.
  • stiffeners are not needed where prior art panels for the same application needed stiffeners.
  • the composites are of lighter weight for equivalent strength since strength to weight ratio is increased.
  • symmetrical as used in the specification and claims with reference to a laminate or layup means that the stack of reinforcing layers on one side of the center of the laminate and their orientation is duplicated on the other side.
  • the term is used to describe such layups or laminates even if only one side has a surface veil and/or a film layer.
  • layer with reference to reinforcing layers includes a single physical layer of reinforcement, whether or not these are individually of “multi-layer” construction, such as a bidirectional or multiaxial layer of reinforcement.
  • the Class A surface of the panels of the invention is achieved by the use of the "surface veil,” and an optional film overlying the veil, that is added to the side of the layup where the Class A surface is to be formed.
  • This veil (and film) mask the underlying reinforcing layers, and thereby minimize "print-through” of these layers to the surface.
  • the veil also holds resin at the laminate surface (when no film is present) to assist in forming the surface gloss.
  • the veil may be selected from non-woven mat or felt able to absorb resin and compressible to absorb mild irregularities in surfaces against which it is pressed.
  • the veil may be made of polyester fibers, glass fibers, carbon fibers, aramid fibers, cotton fibers, mixtures of these fibers and any other fiber that can withstand the consolidation temperature.
  • the surface veil is preferably selected from materials that have an areal weight of about 60 to about 500g/m 2 , more preferably about 100 to about 300g/m 2 and most preferably about 140g/m 2 .
  • the thickness of the veil will depend on the coarseness of the underlying reinforcement, and the need to prevent print-through of this coarse weave. For this reason, it is preferred that the veil be underlaid with a unidirectional fiber layer.
  • the surface veil may be overlaid with a film.
  • the film may be selected from the “dry films,” and the “wet films.” The purpose of the film is to reduce or eliminate pin-holing of the laminate surface, and to assist paint adherence to the surface. The film also reduces the amount of release agent that must be added to the mold for ready release of the laminate from the mold.
  • the preferred "dry films” of the invention include TEDLAR® (product of DuPont of Delaware), and other thermoplastic, thermosetting, or elastomeric films, such as PAINT ON A ROLL® (product of Avery Denison); and other commercially available films.
  • the film has a thickness in the range 0.001 to .125 inches. -7-
  • the "wet" films are selected from resinous coatings or gelcoats.
  • the resinous coatings and gelcoats may be applied to either the surface of the mold or to the reinforcements.
  • the gelcoats may be selected from any gelcoat that is compatible with the resin matrix of the panel.
  • the reinforcing layers that are useful in the composite panels of the invention include a wide variety of commercially available reinforcing layers. Reinforcing layers may be selected for a particular purpose, depending upon the type of panel being produced. Thus, while layers that comprise plies with unidirectional fibers are preferred, multiaxial materials are also useful, especially in larger panels.
  • non-woven materials may also be used as "reinforcing layers.”
  • the type of reinforcing layers selected depends upon several factors, including for example, the load to which the panel will be subjected, and cost factors.
  • a reinforcing layer may include unidirectional fibers, and could comprise a multiaxial ply, depending upon the application.
  • the proportion of reinforcement may be in the range 60-65 wt%, based on the weight of the laminated panel.
  • the composite panels of the invention optionally include a central, compressible core for certain applications.
  • the core is of a non-woven fleece material that is at least somewhat compressible under molding conditions to aid the panel in conforming to the shape of the mold during consolidation.
  • the core may be made from a wide variety of non- woven, compressible material including, for example, glass fiber, polyester fiber, carbon fiber and the like, and mixtures of materials.
  • these polymers may be selected from thermosetting polymers, such as the epoxy resins, phenolic resins, polyester, vinyl ester, polyvinylester, polyimide, modified acrylic, polyurethane, bismaleimide, and the like, and hybrids of these.
  • Additives including fillers (both reinforcing and nonreinforcing), low-profile agents to reduce resin shrinkage, mold-release agents, surfactants, thickening agents, foaming agents, flame retardants, pigments, diluents and electrical conductors to dissipate electrostatic charge may be added to the resin(s).
  • the polymer/additive combination is selected to minimize shrinkage, thereby reducing the likelihood of print-through and facilitating the production of a Class A surface.
  • An important additive to the resin or resin mixture is an agent that dissipates residual charge on the consolidated panel to facilitate the electrostatic application of paint coatings. Examples of these electrically conductive additives include carbon black and powdered metals.
  • fillers reduce the amount of resin needed thereby reducing costs. Fillers also assist in masking underlying reinforcement from the surface. Therefore, for laminates with reinforcing layers that are not smooth and unidirectional, addition of a high proportion of filler, in the range of about 20 to about 45 vol. % (of the resin) is preferred.
  • Hi-Sil 233 (thixotropic additive) 0-12 0.7
  • the useful cure temperature range may be between, but not limited to 50°C-200°C.
  • the preferred range is between 60°C-150°C.
  • FIGURES are illustrative of preferred embodiments of the invention, and do not limit the scope of the invention. Instead, they are intended to -9-
  • FIGURE 1 is a schematic, simplified, not-to-scale, end view of a layup for a structural panel in accordance with the invention.
  • the layup 10 is made up of a number of layers.
  • the central layer 12 is a compressible core.
  • the layup 10 is "symmetrical" in the sense that the layers on either side of the core 12 are identical in both composition and orientation. However, in this embodiment only one side has a drapeable veil 14 to screen any print-through of underlying layers. This side is the "A" side.
  • the layup 10 illustrated in FIGURE 1 is "symmetrical except for the veil on the A side.”
  • On either side of the central core 12 is a weft ply 16 of unidirectional fibers oriented in the 90° direction.
  • Adjacent to, and outside of, each of the 90° plies 16, is a warp unidirectional ply 18, with fibers oriented in the 0° direction.
  • Finally, on the A side only, is a veil or mat 14 of compressible fibrous material.
  • the layered structure of FIGURE 1 is consolidated in a press equipped with smooth mold surfaces to produce a structural panel having a Class A surface on the A side, as explained below with reference to methods of the invention.
  • FIGURE 2 shows a layup identical to that of FIGURE 1, except for the addition of a "dry" film 20 overlying the veil 14.
  • the flexural strength of the structural panels are at least about 270 MPa, and preferably in the range from about 350 to about 700 MPa, even without the addition of added-on stiffeners, or molded-on stiffeners. This represents a significant advance over the prior art where such strength properties could only be obtained with the addition of stiffeners.
  • This important property is the direct result of the use of a high proportion of reinforcing material in the invention, as compared to prior art structural panels, while maintaining a Class A surface without print-through and without requiring subsequent abrasive or other surface treatments to improve surface smoothness.
  • the methods of preparing the structural panels of the invention may be practiced with commercially-available equipment, or with equipment customized for greater automation.
  • the method of the invention includes a stratified cure process that uses a variety of curing agents, specific to layers of the laminate, to control the cure time of the resin and matrix resin flow at that layer.
  • stratified cure of the resin(s) is to produce out-of-mold composite -10-
  • laminate panels with a Class-A surface The process includes the elimination of surface pinholes and surface print-through of materials. "Pinholes” on the surface are primarily caused resin curing around gas bubbles entrapped between the composite and the molded surface. "Print-through” on the surface of a composite panel is a defect that is primarily caused by the use of materials with unlike properties which have differences in shrinkage during either the curing or cool down processes, materials with like properties can cause print-through or some surface defects by having thickness changes within the part. That is, upon curing or cool down the thicker areas shrink more than the thinner areas. Depending on the construction of the composite panel controlling the cure rates and use of resin characteristics varies, materials that are, for example, coarsely constructed such as knitted, woven or material that have gaps typically would cause surface print-through.
  • a composite panel may be constructed of five sequentially stacked layers with layer 4 closest to the veil layer, layer 5.
  • the panel may be produced by the following method of curing the resin:
  • Layer 1 - This layer may consist of a reinforcement. If the material is of a coarsely constructed reinforcement then the resin gellation or cure should occur before layer 4.
  • Layer 2 - when this layer contains a non-woven core and is used as a buffer then the resin gellation or cure should occur before layer 1. this layer may also contain foamed resin to lessen panel weight and/or cost. This layer may also be a reinforcement. If the material is of a coarsely constructed reinforcement then resin gellation or cure should occur before layer 4.
  • Layer 3 - This layer consists of a reinforcement. If the material is of a coarsely constructed reinforcement then resin gellation or cure should occur before layer 4.
  • Layer 4 If resin cure of this layer is first, then the layer provides the benefit of a buffer that eliminates or reduces print-through on this surface. If the resin cure for this layer is delayed until after the cure of other layers then the laminate can be remolded by further compaction in the pressing process by adding more pressure to create a resin flow. This will remold the surface to fill in defects of previously gelled or cured layers.
  • Layer 4 may be the Class-A surface layer, if the fifth layer is not used. Layer 4 incorporates a surface veil that eliminates print-through produced by materials or -11-
  • layers 1, 2, or 3 may be cured simultaneously as an option.
  • Layer 5 may be substituted for by applying a gelcoat enhances mold surface wetout and eliminates surface pinholes.
  • Layer 5 This layer may be the Class-A surface layer and may include a surface film, sheeting or gelcoat and/or resin modifiers to reduce the risk of producing a pinholed surface. If a pigmented surface film or sheeting has been used, no further paint application is needed.
  • a resin mixture is pre-prepared by the steps in box 50.
  • epoxy resin is combined with the predetermined proportion of filler in a mixer.
  • the combined resin and filler mixture in liquid form, is then pumped from the mixer to resin mixture holding tanks. From these holding tanks, the resin mixture is pumped, under manual or electronic control, to the dispensing head of a resin mixture dispenser to apply the resin to layers of the layup to be consolidated into the panel.
  • Other methods of resin mixture preparation and application may also be useful.
  • the illustrative example of a layup to be consolidated is prepared by first cutting a reinforcing ply, such as a glass fiber or carbon fiber ply, to the required size and shape in step 52. Then, resin is applied 54 to the laid down cut fiber ply, in a proportion of from about 30 to about 95 wt % resin, based on the total volume of resin, filler and fiber of the cured laminate, and depending upon the nature of the resin and the type of fiber. Next, a second ply is cut in step 56 to form a second layer that is laid over the first layer. In step 58, resin mixture is applied to the second fiber ply.
  • a reinforcing ply such as a glass fiber or carbon fiber ply
  • a mat core is cut and laid down over the previously laid down and wetted layers that will ultimately form the "B" side of the panel.
  • resin mixture is then applied to the mat core.
  • a third layer is cut and laid on the mat 64, resin mixture is applied to this layer 66.
  • a fourth layer is cut 68 and laid on top of the resin wetted third layer, and the fourth layer is in turn is wetted with the resin mixture 70.
  • the last reinforcing layer that underlies the veil preferably has a ply of unidirectional fibers.
  • a surface veil is cut from a drapeable material and laid over the layup.
  • the surface veil could also be the first layer that is laid down. Either way, this would ensure that the surface veil is immediately adjacent the surface that is to have the Class A surface finish.
  • Resin is then applied 74 to the cut surface veil.
  • a film may then be applied over the veil. The entire layup is transferred to a press where it is consolidated 76 under heat and pressure into a laminate.
  • planar laminates and panels may be produced in accordance with the invention, the invention is particularly useful and advantageous for making contoured panels.
  • Prior art methods on the other hand, experience great difficulty in producing contoured panels, especially with a Class A surface finish.
  • a layup having a first surface veil (or film) as the top layer, and another surface veil (or film) as the bottom layer can be consolidated into a panel with Class A surfaces on both sides.
  • the consolidated panel is removed from the press while the part is still hot, and is removed with vacuum chucks on the "B" side, assisted with air ejectors on the "A" side.
  • the "A" side of the hot panel is not touched during the entire operation, to preserve surface finish. Thereafter, a water jet may be used to trim the part to size, and the edges may be deburred.
  • a final structural panel with Class A surface is produced without need for further surface modifying treatments.
  • the invention provides a method of vacuum molding the panels of the invention.
  • the mold is modified as shown in FIGURE 4 so that it may be partially closed while a vacuum is drawn on its contents.
  • FIGURE 4 illustrates a seal plate 30 with elastomeric seals 36 that engage the top mold half 32 prior to full closure of the mold. This allows a vacuum to be created in the mold cavity 33 around the material charge 34 by evacuating the air through the tube 35. The mold then closes further and compresses the material charge.
  • the mold may be fitted with knife edges for cutting the molded laminate to size and shape desired, as shown in FIGURE 5.
  • top mold half 40 and the bottom mold half 41 are shown compressing the material charge 42.
  • Two hardened cutting blades, one stationary 43 and one moving 44 cut off the material hanging out the mold. This results in a molded part which does not require trimming after the part is removed from the mold.
  • the reinforcing layers are first consolidated to produce an unfinished panel. Thereafter, the veil is applied to the side of the laminate on which a Class A surface is desired. Optionally, a film is applied over the veil. The layup is then consolidated to form the Class A surface on the panel.
  • the materials that provide structural strength to the panel are molded twice, while the materials that provide the Class A surface are only molded once.
  • the veil may be molded first and then consolidated with the reinforcing layers.
  • a layup was prepared, in accordance with FIGURE 2.
  • Each of the layers were as follows in sequence, from the center:
  • the resin mixture utilized is as follows:
  • Wood flour 14010 from American Wood Fibers of Scholfield 784 grams
  • the resin was applied at the following rates for each layer, from the B-side to the A-side:
  • Example 2 The resulting panel was painted and evaluated by the surface evaluation expert of a major automotive company and determined to be production-acceptable Class-A.
  • Example 2 The resulting panel was painted and evaluated by the surface evaluation expert of a major automotive company and determined to be production-acceptable Class-A.
  • a panel with a Class-A surface was produced as follows, from the following layup, commencing on the "B" side:
  • Resin Batch Ingredients gms.
  • the press platens were preheated to 180°F (82°C) and the materials for the layers 1-7 were cut into 17 inch squares.
  • a batch of resin was premixed. 43.7 grams of hardener No. 1 was added to each of 4 batches of the resin, which were then applied to each of layers 1-4. 24.8 grams of hardener No. 2 was added to each of the remaining two batches, which were each then applied to layers 5 and 6.
  • Film layer number 7 was placed onto the lower press platen, and the edges secured with the tape. The remaining layers were stacked in decreasing number sequence on top of layer 7. To ensure complete material wetout with the resin, the press was initially slowly closed to a part thickness of 0.25 inches. While the resin in layers 5 and 6 were still flowable, and during the time of onset of gellation or cure of layers 1-4, the press was closed to a final part thickness of 0.23 inches. The cure was monitored by the dielectrometer instrument. The part was molded for about 12 minutes. Upon inspection of the panel produced by the above method, it was found to have a Class-A surface finish.
  • the structural panel 120 is substantially identical in construction and materials as that described above for the preferred embodiment, with the most notable exception being a lack of a veil.
  • the structural panel 120 includes a bottom reinforcement layer 122, a reinforcement layer 124, an optional core 126, first and second multi-layer reinforcements 128 and
  • the bottom reinforcement layer 122 is bonded to the reinforcement layer 124 by a layer of resin 134.
  • the reinforcement layer 124 is bonded to the core 126 only at predetermined contact positions by a layer of resin 136.
  • the core 126 includes a partial layer of reinforcement 138a-138d disposed at the sides of the core 126. As a result, an increased amount of resin 136 is applied in the areas of the reinforcement layer 124 that are in contact with the partial layers of reinforcements 138a-138d.
  • reinforcement 138a-138d are disposed at the sides of the core 126, other locations, such as a continuous layer of reinforcements, are also within the scope of the present invention. Additionally, while the inclusion of the partial layers of reinforcements 138a-138d is preferred, such reinforcements are not required and, therefore, a structural panel 120 without the reinforcements 138a-138d is also within the scope of the invention.
  • the core 126 is bonded to the first multi-layer reinforcement 128 by an application of resin 140 only at predetermined contact positions, as described above for the resin layer 136.
  • the first multi-layer reinforcement 128 includes preassembled upper and lower reinforcement layers 142 and 144.
  • the second multi-layer reinforcement 130 also includes preassembled upper and lower reinforcement layers 142 and 144.
  • the first and second multi-layer reinforcements 128 and 130 are bonded together by a layer of resin 152.
  • the structural panel 120 includes two multi-layer reinforcements, 128 and 130, more or fewer multi-layer reinforcements are also within the scope of the present invention.
  • the structural panel 120 may include the film layer 132.
  • the film layer 132 may be selected from the same "dry films,” and “wet films” described above.
  • the preferred dry film 132 may be bonded to the structural panel by a layer of resin 154.
  • a layup was prepared, in accordance with FIGURE 6.
  • Each of the layers were as follows in sequence, from the bottom:
  • the resin-wetted layup is then placed in a mold that is closed slowly by the molding process, as is described in greater detail below.
  • the layup is then cured at a temperature of 63 °C for both the A-side and B-side of the mold.
  • the panel then is cured for 35 minutes.
  • the resin mixture utilized is as follows:
  • the resin was applied at the following rates for each layer, from the B-side to the A-side:
  • FIGURES 7-10 another method of preparing structural panels in accordance with the present invention will now be discussed in greater detail. As briefly noted above, for the purpose of reducing void content and surface -19-
  • a vacuum may be achieved in the press around the material charge prior to compressing the material charge.
  • a commercially available press 220 includes upper and lower platens 222 and 224. Attached to opposing surfaces of the upper and lower platens 222 and 224, in a manner well- known in the art, is an upper mold 226 and a lower mold 228, respectively. Opposing surfaces of the upper and lower molds 226 and 228 may be configured for a variety of contours or shapes.
  • a material charge 229 is removably disposed between the upper and lower molds 226 and 228 on a clamping frame 230 by well- known clamps 232a and 232b.
  • the clamping frame 230 is disposed between the upper and lower molds 226 and 228 on a well-known support structure 234.
  • clamping frame 230 is indexed between the upper and lower molds 226 and 228 by a tooling ball and cap fixture 236, as is well-known in the art.
  • the press 220 includes a vacuum chamber 238.
  • the vacuum chamber 238 includes a rectangularly shaped upper C channel 240 defining the upper vacuum chamber, a rectangularly shaped lower C channel 242, an elastomeric vacuum seal 244 housed within a housing 245 and a vacuum seal surface 246.
  • the vacuum seal 244 is rigidly fastened to the lower edge of the upper C channel 240 by well-known fasteners, such as rivets or screws, extending through the lower edge of the C channel 240 and into the vacuum seal housing 245.
  • the vacuum seal surface 246 is a substantially planar member that extends along the upper edge of the lower C channel 242.
  • FIGURES 8-10 As seen in FIGURE 8, the material charge 229 is disposed between the upper and lower molds 226 and 228 and indexed therebetween on the support structure 234. The lower mold 228 is driven upwards until the seal surface 246 is received within the seal housing 245 and engages the vacuum seal 244, as seen in FIGURE 9. After the seal surface 246 is sealingly received against the vacuum seal 244, the vacuum chamber 238 is evacuated by a tube 250 and well-known evacuation means (not shown). The tube 250 extends through the lower C channel 242 and is sealed therein by a well-known seal (not shown). Preferably, the vacuum chamber 238 is evacuated above 28 inches of mercury. Although a vacuum -20-
  • the process begins a dwell period.
  • heat is transferred from the upper and lower molds 226 and 228 to the material charge 229.
  • the heat transfer causes the resins to become less viscous and fill voids within the material charge 229, thereby drawing out pockets of air.
  • the dwell period may last between, but is not limited to, 0-60 seconds.
  • the upper and lower molds 226 and 228 continue to compress the material charge 229, at a useful rate range of .0001-1 inches per second, preferably at a rate of .01 -.02 inches per second.
  • the compression step continues until the lower mold 228 reaches a predetermined distance.
  • the material charge 229 has fewer imperfections due to entrapped air and results in a panel that is lightweight, strong and does not include a veil.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Quality & Reliability (AREA)
  • Laminated Bodies (AREA)

Abstract

La présente invention concerne des panneaux structurels composites faits de couches consolidées de matériau de renforcement incluses dans une matrice de résine et pourvues d'un revêtement de classe A. L'invention concerne également un procédé de production de tels panneaux. L'une des caractéristiques principales de l'invention est de placer sous la couche de revêtement de classe A un voile non tissé (ou une pellicule recouvrant le voile) capable de former un drapé sur une couche de revêtement conformée avant la consolidation aboutissant à la formation définitive du stratifié. Le voile permet de réduire, voire de supprimer, sur le revêtement, les effets de décalque par transparence depuis la couche soujascente de renforcement. La pellicule éventuellement disposée sur le voile réduit l'importance des défauts en trous d'épingle et favorise l'adhérence de la peinture. Dans certaines réalisations, lorsqu'on recherche une certaine rigidité, les panneaux comportent une couche noyau centrale. L'invention concerne également des procédés de fabrication de tels panneaux. Ces panneaux structurels, qui sont bien plus résistants que les panneaux selon l'état antérieur de la technique, permettent, pour la plupart des applications, de se dispenser de raidisseurs sur les faces inférieures.
PCT/US1999/001710 1998-01-28 1999-01-28 Panneaux composites a revetement de classe a WO1999038683A1 (fr)

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US1502898A 1998-01-28 1998-01-28
US09/015,028 1998-01-28

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1211054A1 (fr) * 2000-12-01 2002-06-05 Bayerische Motoren Werke Aktiengesellschaft Procédé pour la fabrication d'une structure composite renforcée par des fibres
DE102007043932A1 (de) * 2007-09-12 2009-03-26 Volkswagen Ag Harzinjektionsverfahren und Werkzeug für ein Harzinjektionsverfahren
WO2009130120A1 (fr) * 2008-04-23 2009-10-29 Airbus Operations Gmbh Dispositif et procédé de production d'un composant et composant ainsi obtenu
DE102012208914A1 (de) * 2012-05-25 2013-11-28 Bombardier Transportation Gmbh Sitz für den Innenraum eines öffentlichen Verkehrsmittels mit farblich gestalteter Gewebelage
WO2013178757A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
WO2014088905A1 (fr) * 2012-12-07 2014-06-12 Hanwha Azdel, Inc. Articles comprenant des fibres non tordues et leurs procédés d'utilisation
US8932697B2 (en) 2006-07-12 2015-01-13 Hexcel Composites Limited Composite material assembly
WO2016102415A1 (fr) * 2014-12-23 2016-06-30 Hexcel Composites Limited Matériaux de moulage à fini de surface amélioré
WO2018001641A1 (fr) * 2016-07-01 2018-01-04 Gurit (Uk) Ltd Moulage de panneaux composites
US10065393B2 (en) 2006-03-25 2018-09-04 Hexcel Composites Limited Structured thermoplastic in composite interleaves
CN110103487A (zh) * 2019-05-16 2019-08-09 沈阳飞机工业（集团）有限公司 一种成型z形截面复合材料零件的工艺方法
US10618227B2 (en) 2006-03-25 2020-04-14 Hexcel Composites, Ltd. Structured thermoplastic in composite interleaves

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5204170A (en) * 1991-08-01 1993-04-20 Basf Corporation High density structural reaction injection molded composite containing a fabric of nonwoven spunbonded fibers made of a polyester core sheathed in a polyamide skin embedded in a polyurethane matrix
US5391344A (en) * 1991-11-26 1995-02-21 Miles Inc. Production of Class A surface of fiber reinforced polyurethane molded products
US5414037A (en) * 1993-03-08 1995-05-09 Chrysler Corporation Composition for molding of vehicle body panels
US5429865A (en) * 1993-09-06 1995-07-04 Rutgerswerke Aktiengesellschaft Composite materials

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5204170A (en) * 1991-08-01 1993-04-20 Basf Corporation High density structural reaction injection molded composite containing a fabric of nonwoven spunbonded fibers made of a polyester core sheathed in a polyamide skin embedded in a polyurethane matrix
US5391344A (en) * 1991-11-26 1995-02-21 Miles Inc. Production of Class A surface of fiber reinforced polyurethane molded products
US5414037A (en) * 1993-03-08 1995-05-09 Chrysler Corporation Composition for molding of vehicle body panels
US5429865A (en) * 1993-09-06 1995-07-04 Rutgerswerke Aktiengesellschaft Composite materials

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1211054A1 (fr) * 2000-12-01 2002-06-05 Bayerische Motoren Werke Aktiengesellschaft Procédé pour la fabrication d'une structure composite renforcée par des fibres
US10618227B2 (en) 2006-03-25 2020-04-14 Hexcel Composites, Ltd. Structured thermoplastic in composite interleaves
US10065393B2 (en) 2006-03-25 2018-09-04 Hexcel Composites Limited Structured thermoplastic in composite interleaves
US8932697B2 (en) 2006-07-12 2015-01-13 Hexcel Composites Limited Composite material assembly
DE102007043932A1 (de) * 2007-09-12 2009-03-26 Volkswagen Ag Harzinjektionsverfahren und Werkzeug für ein Harzinjektionsverfahren
WO2009130120A1 (fr) * 2008-04-23 2009-10-29 Airbus Operations Gmbh Dispositif et procédé de production d'un composant et composant ainsi obtenu
US8454878B2 (en) 2008-04-23 2013-06-04 Airbus Operations Gmbh Device for producing a component and method and component
DE102012208914A1 (de) * 2012-05-25 2013-11-28 Bombardier Transportation Gmbh Sitz für den Innenraum eines öffentlichen Verkehrsmittels mit farblich gestalteter Gewebelage
RU2626777C2 (ru) * 2012-05-25 2017-08-01 Бомбардир Транспортацион Гмбх Сиденье для салона общественного транспортного средства со слоем ткани с цветовым решением
CN104540718A (zh) * 2012-05-25 2015-04-22 庞巴迪运输有限公司 具有有色地构成的织物层的用于公共交通工具的内部空间的座椅
GB2502653B (en) * 2012-05-30 2015-11-04 Gurit Uk Ltd Press moulding method
US9981430B2 (en) 2012-05-30 2018-05-29 Gurit (Uk) Ltd. Press moulding method
WO2013178753A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
WO2013178751A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
WO2013178750A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
GB2502651B (en) * 2012-05-30 2015-11-04 Gurit Uk Ltd Press moulding method
GB2502652B (en) * 2012-05-30 2016-03-23 Gurit Uk Ltd Press moulding method
WO2013178757A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
WO2013178754A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage par compression
US10118349B2 (en) 2012-05-30 2018-11-06 Gurit (Uk) Ltd. Press moulding method
US9902117B2 (en) 2012-05-30 2018-02-27 Gurit (Uk) Ltd. Press moulding method
US10112352B2 (en) 2012-05-30 2018-10-30 Gurit (Uk) Ltd. Press moulding method
US9981431B2 (en) 2012-05-30 2018-05-29 Gurit (Uk) Ltd. Press moulding method
US9981432B2 (en) 2012-05-30 2018-05-29 Gurit (Uk) Ltd. Press moulding method
WO2013178748A1 (fr) * 2012-05-30 2013-12-05 Gurit (Uk) Ltd Procédé de moulage à la presse
WO2014088905A1 (fr) * 2012-12-07 2014-06-12 Hanwha Azdel, Inc. Articles comprenant des fibres non tordues et leurs procédés d'utilisation
GB2566000A (en) * 2014-12-23 2019-03-06 Hexcel Composites Ltd Moulding materials with improved surface finish
WO2016102415A1 (fr) * 2014-12-23 2016-06-30 Hexcel Composites Limited Matériaux de moulage à fini de surface amélioré
WO2018001641A1 (fr) * 2016-07-01 2018-01-04 Gurit (Uk) Ltd Moulage de panneaux composites
CN110103487A (zh) * 2019-05-16 2019-08-09 沈阳飞机工业（集团）有限公司 一种成型z形截面复合材料零件的工艺方法
CN110103487B (zh) * 2019-05-16 2021-05-18 沈阳飞机工业（集团）有限公司 一种成型z形截面复合材料零件的工艺方法

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