WO2014200374A1 - Noyau et procédé de fabrication - Google Patents

Noyau et procédé de fabrication Download PDF

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Publication number
WO2014200374A1
WO2014200374A1 PCT/PT2013/000036 PT2013000036W WO2014200374A1 WO 2014200374 A1 WO2014200374 A1 WO 2014200374A1 PT 2013000036 W PT2013000036 W PT 2013000036W WO 2014200374 A1 WO2014200374 A1 WO 2014200374A1
Authority
WO
WIPO (PCT)
Prior art keywords
holes
layers
core
cork
overlapped
Prior art date
Application number
PCT/PT2013/000036
Other languages
English (en)
Inventor
António Manuel Pereira DA CUNHA RIBEIRO VALENTE
Original Assignee
Da Cunha Ribeiro Valente António Manuel Pereira
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 Da Cunha Ribeiro Valente António Manuel Pereira filed Critical Da Cunha Ribeiro Valente António Manuel Pereira
Priority to PCT/PT2013/000036 priority Critical patent/WO2014200374A1/fr
Publication of WO2014200374A1 publication Critical patent/WO2014200374A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B32/00—Water sports boards; Accessories therefor
    • B63B32/57—Boards characterised by the material, e.g. laminated materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • 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
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/02—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising animal or vegetable substances, e.g. cork, bamboo, starch
    • 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
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/04—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material

Definitions

  • the present invention relates to a core for being placed between two surface skins of a sandwich panel, and specifically to a cork core, and a method for manufacturing said core.
  • the invention focuses on a core comprising at least two cork agglomerate layers that define regular macro cavities or spaces within at least the two surface skins of the sandwich panel that is formed by the cork core and the skin panels, although other materials or elements can be included between the skins of the panel .
  • the field of application of the present invention is encompassed within the technical sector of the sandwich panel technology as a base material for core production.
  • sandwich panel cores are low in density and lightweight, but when face sheets are combined with reinforcing fibers and resin, the sandwich panels become incredibl light, stiff, and strong structured. Actually, and based in mixing of lightweight cores, new composite skins, and adhering methods, new sandwich structures are constantly being developed for a wide variety of applications.
  • sandwich panels An important advantage of sandwich panels is that the core helps to distribute and absorb an impact on the surface skins.
  • cores such as balsa or foam
  • the skin is in constant contact with the entire core and therefore, during an impact, the force exerted on the skin is distributed over a wider area of the core.
  • honeycomb cores although often stiffer and stronger, have much lower impact resistance as the skin is not in full contact with the honeycomb core.
  • the compression strength of the core helps to prevent the sandwich from common methods of failure such as wrinkling, delaminating., or buckling.
  • the core's shear properties help to maintain the sandwich panels' stiffness and to prevent the skins from "sliding" when bending force is applied.
  • Lightweight honeycomb cores are usually used in the main bodies of airplanes, floors, and bulkhead interior panels. Beyond aerospace, advanced honeycomb, balsa, and foam cores are used significantly in the marine, wind energy, construction, and various transportation industries.
  • the main interesting requirements for core materials can be resumed as low density, high shear modulus, high shear strength, elevated stiffness perpendicular to the faces and good thermal and acoustic insulation features.
  • cork agglomerate cores An alternative to foam cores are cork agglomerate cores. Compared with high performance foams, sandwich components with enhanced cork agglomerates have a higher energy absorption capacity and therefore better crashworthiness properties when impact loading is expected, Cork agglomerates with lower densities present better thermal properties, which is an important issue when considering the design of the mechanically efficient structures with low weight requirements.
  • agglomerate cork cores provide the following properties to a sandwich panel: sustainable green product, fire resistant, high damping properties; low thermal conductivity, and excellent impact properties.
  • Cork has a remarkable combination of mechanical, chemical and morphological features. This natural organic material continues to be widely used. It has evolved from simple, direct usage of the raw material, through products involving some industrial transformation to the point where it now represents a potential source material for high technology industries. Cork agglomerate composites have a long track record in structural and thermal applications, in sectors as diverse and aggressive as aerospace, automotive, building, and energy. Cork agglomerate is resilient, strong (high specific strength) , impervious to water, has a near zero Poisson coefficient, very low thermal conductivity, low density and a complex chemical structure. This combination of properties provides cork with features hard to match with other materials: excellent sealing ability and ease of removal, thermal comfort and damping for walking, thermal insulation at very low temperatures, among others.
  • the cork agglomerates used as core materials form continuous sheets of different width that may have different granule sizes with different adhesion elements depending of the final use of the sandwich panel.
  • the properties of the sandwich panel due to the core material properties will change.
  • An important difference between these cork agglomerate cores and the state of the art cores not made up of cork is the reduced weight of the state of the art cores versus the cork agglomerate cores which properties depend on the granule sizes and the width of the sheet, properties that go against the weight of the core.
  • a core layer with at least two cork agglomerate layers that defines regular macro cavities or spaces within the two surface skins of the sandwich panel that is formed by the cork core and the skin panels.
  • the main objective of the present inventions is a core that reduces the core density to levels that allow the utilization in applications of 50-120 kg/m3 cores range.
  • the utilization of macro-holes generated by overlaying cork layers with macro cavities (diameters above 5mm) produce cork based materials with densities in the range of 50-120 kg/m3.
  • the layered sheets with cavities produce hollow type of cork based cores in opposition to solid or continuous type of cork based cores. Therefore the present invention provides a cork core with a lightweight capacity due to the less material used at the same time that the thermal conductivity is reduced while improving thermal, acoustic insulation and impact properties.
  • the present invention proposes a cork agglomerate core using lightweight thin cork based materials in the form of thin sheet materials with three-dimensional geometries to produce core materials which are joined together with face sheets to produce a light strong sandwich panel structure. Said three-dimensional geometries provide a new solution to closed cells sandwich panels.
  • the term panel should be understood as any product that comprises at least a core with two skins.
  • This invention allows the production of closed cell sandwich panels with different properties of conventional sandwich panel technology, using natural product as core materials.
  • Cork- composites are green, abundant, and are a prime candidate to substitute oil-derived materials such as PVC and synthetic micro-sandwiches. Unlike oil-derived products such as PVC and synthetic micro-sandwiches, cork agglomerates or composites will remain immune to surging oil prices and their volatility.
  • the object of the present invention is, as stated in claim 1, a core for placing between two surface skins of a sandwich panel, comprising at least two overlapped cork agglomerate layers with through holes, being the holes of the at least two overlapped layers off-centered between them.
  • the term off- centered should be understood as holes of the different layers that are not concentric or aligned when both layers are overlapped.
  • the holes can be off-centered by moving a certain distance one layer when it is overlapped over the other layer. In this case the layers are the same.
  • Another option is to have layers of the same sizes but with the holes made in them placed in different positions.
  • the mechanical resistance is superior to that of an equivalent weight drilled block.
  • Said layers are obtained from cork blocks that after having the holes drilled in them are laminated to obtain the layers of the required thickness.
  • the size of the holes and the distance between them is preferably the minimum possible but considering that the layer should have a determined stiffness.
  • the overlapped layers can have holes of different sizes as well as different shapes, circular holes are one possible embodiment.
  • Said cork agglomerate blocks, and therefore the layers, are made up of cork granulates adhered between them with an adhesion element., and determining between said granulates irregular and usually microscopic cavities, less than 0.5 mm, between the granules that form the block or the sheet layer.
  • the present invention proposes a lightweight core made up of at least two cork layers where de cavities or cells are determined by off-centered holes, non-concentric or misaligned, placed along the surfaces of the layers. These layers are afterwards placed between two skins to obtain a sandwich panel.
  • the cells or cavities are formed between the walls of the cork layer and the surface skins, being at least one distance between opposite walls of at least 3 mm.
  • the holes can be circular or have n sides, like five or six sides to form a pentagon or a hexagon.
  • Said at least two cork layers with through non-aligned holes or non-concentric holes are overlapped, one on top of another, so that the at least resulting layers that are in direct contact, do not have holes aligned, forming therefore a core between the surface skins. Therefore, the cell/ cavities between the surface skins are determined by at least two cork layers that are partially overlapped or superimposed by a certain distance.
  • One possible embodiment in case of circular cut is half diameter offset distance and combined with the surface skins of the sandwich panel, with a distance between the two skins of at least 2 mm.
  • the core comprises more than two layers partially overlapped with off-centered holes, and therefore said non-concentric or misaligned holes, results in cells/ cavities between the overlapped layers too.
  • non-concentric overlapped layers are joined with an adhesive and further, stitching of the different layers can be practiced to increase the mechanical properties of the core, and/or in an alternative embodiment interlocking materials can be placed in the holes.
  • interlocking materials can be placed in the holes.
  • the use of filler materials under determined configurations will fill the non-concentric holes generating a three dimensional mechanical interlocking effect between layers.
  • stitching and filling of the holes can be made in the same core.
  • Said filing material is preferably a light material, such as cork granulates or foam of an appropriate material.
  • the way of joining the layers will depend on the final application of the core. Bonding might be affected by environmental aspects like humidity and temperature, and these can make the bonding weaker along the time. Further, adhesive bonding is strong for shear loads but weak on tension. The stitching of the layers provide a more stable and long-lasting joining, that improves the mechanical strength for tension loads . When a light core is needed the holes will be usually empty to reduce the weight, but when certain properties are needed, such as damping or vibration mitigation, the holes will be filled with materials as previously stated.
  • the core object of the present invention can be used in different products such as industrial sandwich panels for general applications as primary and secondary structures for load carrying purposes, sound, vibration and thermal insulation.
  • Another object of the present inventions is a manufacturing method for agglomerate cork cores comprising the following steps :
  • Said joining can be made by bonding or by stitching the cork layers or by the combination of both, bonding and stitching.
  • stitching can be made before the adhesive is cured or after being laminated, and for example with pressure sensitive adhesives .
  • the non-concentric or misalign holes can be filled with light materials, like foam or granulates, in order to provide mechanical interlocking and improved mechanical resistance and dampening. Specific properties can also be obtained upon the utilization of specific materials.
  • a further object of the invention is a surfboard that comprises a core as the one previously described.
  • a surfboard with the above mentioned cork core is lighter than conventional 120 kg/m 3 cork agglomerate materials and with a similar weight than synthetic foams.
  • the advantage compared with this last case is not the weight but a sustainable solution, ecological from both the materials use and recycling and also from the point of view of surfboards manufacturing as well as the industrial workers health and safety, superior fire resistance, vibration dampening, feeling comfort and enhanced crushing capability.
  • Figure 1 shows a perspective view of a cork layer with trough holes.
  • Figure 2 shows a perspective view of three cork layers Overlapped with the holes of the sides off-centered with respect to the middle layer.
  • Figure 3 shows the steps for manufacturing a core for a panel made up of cork layers and a different view of the overlapped layers can be seen in figure 3A.
  • Figure 4 shows an embodiment of the invention applied to a surf-board.
  • Figure 5 shows a top view of the layers of a surf-board according to the invention and a section of the layers.
  • Figure 1 shows a cork layer (100) with through holes (101) along the surface of the layer (100) .
  • Said holes (101) can be circular or with n-sides, as the ones in the figure that have six sides determining hexagonal holes or cavities (101) .
  • the holes (101) on a layer (100) can have the same geometry or different one, and as well they can have a uniform distribution o the surface of the layer (100) or a particular one depending on the technical requirements of the core.
  • the distance between opposite walls of the holes (101) , or the diameter of said holes, if the same are circular, should be of at least 3 mm.
  • a cork core (150) is shown comprising three Cork layers (100, 200, 300) as the ones described in the previous embodiment. Said cork layers (100, 200, 300) are placed one on top of the other with the middle layer (200) slightly displaced half the dimension of the hole dimension (101), so that the holes (101, 301) of the two side layers (100, 300) are centered between them and are off-centered with regards, to the holes (not shown) of the middle layer (200) . On the upper surface (102) of the top layer (100) and on the lower surface (303) of the lowest layer (300) skins are place to form a sandwich panel.
  • FIG 3 different steps for manufacturing a cork agglomerate core according to the invention is shown.
  • the cork layers (100, 200, 300) are obtained from a block (400) of pressed cork by cutting the same with a thickness of approximately 10 mm each layer. A minimum 1 mm layer thickness can also be obtained by this process.
  • the through holes (101) are made in the cork agglomerate layers having, in this example, a diameter of 28 mm and each layer a thickness of 10 mm (100, 200, 300). Said layers (100, 200, 300) are then overlapped with a hole half-diameter off-centered and joined together.
  • the holes of the side layers (100, 300) are centered between them but the holes in the middle layer (200) are off- centered in respect to the side layers ones (100, 300) .
  • the alternated layers preferably have centered holes while the side- by-side layers, or layers in direct contact, have off-centered holes. This can be seen in Fig 3A.
  • An alternative to figure 3 consists of obtaining the cork layers from at least one drilled block of pressed cork that after being drilled are sliced, obtaining layers with a thickness or width of approximately 10 mm each layer. Said layers are then overlapped as previously explained. The minimum layer thickness that can be obtained by this process is also 1 mm.
  • FIG 4 an embodiment of a cork agglomerate core applied to a surfboard (500) is shown.
  • the surfboard has a wood frame (501) that determines the shape of the board, specifically comprising longitudinal beams and transversal elements that determine areas (502) between the longitudinal strips.
  • cork agglomerate cores (150) are placed with the shape of the space (502) .
  • the cork layers (100, 200, 300) of the core (150) have through holes as the ones previously explained.
  • the number of cork layers is determined depending of the buoyancy required for the case of a surfboard or depending of the particular product specification to be manufactured.
  • the fiber reinforced composite skins (503) are applied to both surfaces of the cores (150) and frame (501) .
  • the advantage of this construction is a lighter surfboard when compared with conventional 120 kg/m 3 cork agglomerate materials and a surfboard with a nea equivalent weight when compared with synthetic foams. In this last case the advantage is not the weight but a sustainable solution, ecological from both the materials use and recycling and also from the point of view of surfboards manufacturing as well as the industrial workers health and safety.
  • the layers can be stitched and the holes can be filled with lightweight materials to increase the mechanical properties, of the core or with specific materials for damping and vibration mitigation.
  • Intermediary thin reinforced paper, or fiber materials can be used between cork layers .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Laminated Bodies (AREA)

Abstract

La présente invention concerne un noyau destiné à être placé entre deux revêtements de surface d'un panneau-sandwich, et en particulier un noyau de liège. L'invention se concentre sur un noyau comprenant au moins deux couches agglomérées de liège se chevauchant qui définissent des macro-cavités ou espaces à l'intérieur des deux revêtements de surface du panneau-sandwich qui est formé par le noyau de liège et les panneaux de revêtement. L'invention concerne également un procédé de fabrication dudit noyau.
PCT/PT2013/000036 2013-06-14 2013-06-14 Noyau et procédé de fabrication WO2014200374A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/PT2013/000036 WO2014200374A1 (fr) 2013-06-14 2013-06-14 Noyau et procédé de fabrication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/PT2013/000036 WO2014200374A1 (fr) 2013-06-14 2013-06-14 Noyau et procédé de fabrication

Publications (1)

Publication Number Publication Date
WO2014200374A1 true WO2014200374A1 (fr) 2014-12-18

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018083019A1 (fr) * 2016-11-03 2018-05-11 Brauers Rouven Dirk Élément en matériau composite, notamment pour engins de sport

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1084353A (fr) * 1965-08-11
FR2887780A1 (fr) * 2005-07-01 2007-01-05 Airkide Sarl Planche de glisse et procede de fabrication d'une telle planche
EP2422948A1 (fr) * 2009-04-20 2012-02-29 Ángel Rodríguez Arnal Procédé de fabrication de noyaux de planche de surf en liège noir

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1084353A (fr) * 1965-08-11
FR2887780A1 (fr) * 2005-07-01 2007-01-05 Airkide Sarl Planche de glisse et procede de fabrication d'une telle planche
EP2422948A1 (fr) * 2009-04-20 2012-02-29 Ángel Rodríguez Arnal Procédé de fabrication de noyaux de planche de surf en liège noir

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018083019A1 (fr) * 2016-11-03 2018-05-11 Brauers Rouven Dirk Élément en matériau composite, notamment pour engins de sport

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