Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D88/00—Large containers
  • B65D88/02—Large containers rigid
  • B65D88/12—Large containers rigid specially adapted for transport
  • B65D88/121—ISO containers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D90/00—Component parts, details or accessories for large containers
  • B65D90/02—Wall construction
  • B65D90/022—Laminated structures
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D90/00—Component parts, details or accessories for large containers
  • B65D90/02—Wall construction
  • B65D90/023—Modular panels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D90/00—Component parts, details or accessories for large containers
  • B65D90/02—Wall construction
  • B65D90/08—Interconnections of wall parts; Sealing means therefor

Definitions

• the present invention relates to freight containers.
• the invention particularly relates to the impact resistance of freight containers, particular to impacts from handling equipment.
• freight containers are preferably of a standard size, such as freight containers conforming to the ISO standards for containers.
• An ISO (International Standards Organization) container is a freight or shipping container that complies with one or more relevant ISO container standards, such as the ISO 1496 series.
• Types of freight containers may vary according to their application, but include nominal 20 and 40 foot ISO containers and 10, 25, 30 and 45 foot containers and SWAP bodies for conveyance of goods by road, rail and/or sea.
• the containers of the present invention include general purpose, thermal (e.g. insulated, refrigerated, heated) or bulk containers as described in the ISO 1496 series, but also include non ISO containers and SWAP bodies.
• the ISO container standards provide minimum structural properties relating to the strength of the walls, roof and floor. Rigidity and weatherproofing standards are also set. The standards ensure that the containers are suitable for purpose as freight, shipping or cargo containers.
• freight or shipping containers generally have used a metal framework with composition board (usually steel or aluminium sheathed) or other composite material panels attached to the framework by bolts, rivets or welding.
• composition board usually steel or aluminium sheathed
• other composite material panels attached to the framework by bolts, rivets or welding.
• Corner fittings are then attached, in accordance with ISO standards, to each corner of the shipping container.
• the corner fittings are used to secure cables and other components to the shipping containers during loading, unloading and handling of the containers, as well as to secure the containers to one another and to the transport vehicle.
• a freight container comprising:
• a frame a frame; a roof, a floor and walls,
• At least a wall, roof or floor comprising:
• the impact resistant portion comprises a polyurethane rubber.
• polyurethane rubber preferably has an elongation to break (determined at 23°C and 5 mm/min, according to ISO 527) in the range between 2 to 700%, more preferably in the range between 30 to 700% and even more preferably in the range between 500 to 700%.
• impact resistant portion and “proximal portion” may be interchangeable used.
• an attachment point for a lifting device includes fittings containing the attachment means (e.g. apertures to receive a hook from a handling device) and also includes fork pockets (for use in lifting the container with forklift trucks).
• an attachment point refers to a fitting containing attachment means (e.g. apertures to receive a hook from a handling device).
• the container passes the tests described in section 6 of ISO 1496-1 (fifth edition) and/or tests described in section 8 of ISO 1496-2 (fifth edition). All dimensions of the container and panels therein are typical of those used in freight containers and preferably also comply with ISO requirements.
• the freight container comprises a frame to which the walls, roof and floor are attached by means of for example bolts, rivets or welding.
• the attachment point is a fitting attached to the roof or to the frame on the roof side. More preferably, the attachment point is a fitting attached to the frame on the roof side.
• the material of the distal portion and of the impact resistant portion is chosen such that the modulus of elasticity of the distal portion is preferably at least 20% greater than the modulus of elasticity of the impact resistant portion.
• modulus will refer to the modulus of elasticity (E-modulus in bending), unless otherwise stated.
• the modulus of elasticity of the distal portion is at least 30%, more preferably at least 40%, even more preferably at least 50%, even more preferably at least 100%, even more preferably at least 200%, even more preferably at least 300%, even more preferably at least 500%, even more preferably at least 700%and most preferably at least 900% greater than the modulus of elasticity of the impact resistant portion.
• the modulus of elasticity refers to E-modulus in bending. Depending on the material and construction of the portion, the person skilled in the art will know to choose the applicable norm for measuring the modulus of elasticity.
• modulus of elasticity is measured according to ASTM D7249; for an unidirectional fibre-reinforced composite monolayer the modulus of elasticity is measured according to ISO 527; for a polyurethane rubber monolayer the modulus of elasticity is measured according to ASTM D412.
• an impact resistant portion or zone that at least partially absorb the impact energy and an energy dissipating portion or zone (i.e. distal portion) adjoining the impact zone enables the roof, floor or wall containing such an impact resistant and distal portion to more effectively absorb and dissipate impacts during handling.
• the impact resistant portion is required to have the sufficient mechanical properties to withstand impact from attachment forks or hooks which in some cases weigh around 1500 kg. This weight may be drop, fall or swing onto the portion or region immediately surrounding the attachment point, with a contact area of for example about 1000 mm 2 (0.001 m 2 ).
• the impact energy that this region must absorb or dissipate, if the hook falls from a height of just 0.1 meter, is approximately 1.5 kJ (1500 kg (mass) x 9.81 m/s 2 (gravitation acceleration) x height (0.1 m)).
• the impact energy resistance of the impact resistant portion is at least 0.2 kJ, more preferably at least 0.5 kJ, even more preferably at least 1.0 kJ, yet even more preferably at least 2.0, yet still more preferably at least 5 kJ and most preferably at least 10 kJ.
• the dimensions and material of the impact resistant portion are chosen such that the impact resistant portion has an impact energy resistance of preferably at least 0.2 kJ, more preferably at least 0.5 kJ, even more preferably at least 1.0 kJ yet even more preferably at least 2.0, yet still more preferably at least 5 kJ and most preferably at least 10 kJ.
• the impact energy resistance of the impact resistant portion and of the distal portion is measured with the charpy impact test according to IS0179-1.
• the impact resistant portion has an impact energy resistance of for example at least 0.7 kJ in case the impact resistant portion is able to receive an impact energy of at least 0.7 kJ put on the container via the attachment point or on a region surrounding the attachment point with a contact area of about 1000 mm 2 without resulting in that the impact resistant portion either shows permanent deformation or abnormality which will render it unsuitable for use.
• the impact energy resistant test performed on the container preferably uses an attachment hook, attachment fork (i.e. from fork lift), spherical or hemispherical object (e.g. steel ball or dart) having a minimum contact radius of about 5 mm and a minimum weight of about 5 kg.
• Suitable impact testing equipments includes the Instron® range of impact testers including the 9200 and 8100 series (e.g. the 8120 model with a 100 kg impact object).
• the container should not show either permanent deformation or abnormality which will render it unsuitable for use, consistent with the pass criteria used in ISO 1496-1.
• the specific energy absorption (SEA) of the impact resistant portion is preferably at least 10 J/kg/m 2 , more preferably at least 50 J/kg/m 2 , even more preferably at least 80 J/kg/m 2 , yet even more preferably at least 100 J/kg/m 2 and most preferably at least 120 J/kg/m 2 .
• the impact resistant portion preferably has a modulus of elasticity of at least 1 MPa, more preferably at least 3 MPa, even more preferably at least 5 MPa and most preferably at least 10 MPa.
• the modulus of elasticity is no more than 1000 MPa, more preferably no more than 500 MPa, even more preferably no more than 200 MPa and most preferably no more 100 MPa.
• Higher modulus values may result in poor dampening efficiency (i.e. increased chance of failure due to brittle fracture), while lower modulus values may not be sufficient to prevent excessive deformation, which may result in damage to the payload.
• the ratio of the stored modulus ( ⁇ ') (or stored elastic energy) to the loss modulus (E") also known as tan delta ( ⁇ "/ ⁇ ') is used to measure the material's damping effectiveness or the material's ability to dissipate energy. The higher tan delta, the greater the material's ability to dissipate energy.
• tan delta may be used to infer the amount of energy dissipated as heat during deformation of a foam and plastic deformation. It is preferred that the impact resistant portion has a tan delta value that does not vary greatly (e.g. ⁇ 35% variation) over the operating temperature range (e.g. -30 to 70°C). This is particularly so when the impact resistant portions forms part of a broader energy dispersion system, such as that defined in the present invention.
• the ability of a panel of a container to absorb energy through material deformation may be also quantified using the ball rebound test (DIN EN ISO 8307).
• the first aspect of the invention is modified (with the other features remaining the same unless otherwise stated) such that it provides a container comprising an impact resistant portion (P,) which has relatively high energy absorbing properties compared to a distal portion (P d ), as characterized by P, having a % difference compared to P d (i.e.
• the container has at least two, more preferably at least three, even more preferably at least four and most preferably all of the above properties.
• these improved energy absorbing characteristics are present across the operating temperature range (-30 to 70 °C).
• the ability for the impact resistant portion proximal to the attachment point to disperse energy, which has not been already absorbed, is dependant upon the energy dispersive properties of the portion of the panel distal from the attachment point and indeed the whole container.
• the distal portion preferably dissipates energy through vibration.
• the distal portion having a higher modulus of elasticity or higher rigidity.
• the vibration of the distal portion results in energy being dissipated through the movement and optionally through transfer into seals and fasteners where energy is also dissipated through non-permanent material deformation.
• the impact resistant portion and the distal portion may form part of the same contiguous panel or they may be separate panels which are connected by a fastening means, such as a clamp, rivet, bolt, glue and/or adhesive.
• a fastening means such as a clamp, rivet, bolt, glue and/or adhesive.
• an adhesive is applied which adhesive preferably has a composition comprising an elastomeric polymer.
• the two functional components e.g. impact resistant portion and distal portion
• the two components are preferably connected through thermal fusing or polymer welding techniques.
• the impact resistant portion is an impact resistant panel and the distal portion is a distal panel and the distal panel and impact resistant panel are separate panels.
• the impact resistant portion is preferably affixed to the frame by a resilient fastening means, which preferably comprises a spring loaded bolt and/or an adhesive.
• the impact resistant portion and distal portion according to the present invention may be present in part or all of the side walls, end wall, front wall (doors), floor wall and/or roof wall of the container.
• the impact resistant portion and distal portion according to the present invention are present in the roof of the container, as this is where most impacts from handling equipment occur.
• reference to the term panel will mean reference to the wall, roof, floor of the container or part thereof.
• the impact resistant portion may for example be a monolayer or may be a laminate construction.
• the laminate comprises an outer layer, a core layer and an inner layer (e.g. sandwich construction).
• the impact resistant portion is a monolayer, comprising a polyurethane rubber.
• the impact resistant monolayer is made of a polyurethane rubber.
• the thickness of the monolayer is preferably between 10 and 30 mm.
• the impact resistant portion is a laminate construction. The thickness of the laminate construction is preferably between 20 and 30 mm.
• At least one layer of the laminate construction comprises the polyurethane rubber. More preferably, at least one layer of the laminate construction is made of the polyurethane rubber. Even more preferably, the laminate comprises an outer layer, a core layer and an inner layer, whereby the inner and outer layer of the laminate construction comprises the polyurethane rubber. Even more preferably, the laminate comprises an outer layer, a core layer and an inner layer, whereby the inner and outer layer of the laminate construction is made of the polyurethane rubber.
• the core layer is made of material with an elongation to break (determined at 23°C and 5 mm/min, according to ISO 527) in the range between 2 to 400%, more preferably in the range between 100 to 300% and even more preferably in the range between 100 to 200%.
• the core layer preferably comprises a polymeric material that provides a relatively light (in terms of weight) means of providing flexibility to the wall.
• the polymeric material is preferably a polymeric foam as this provides a low density structural material.
• Suitable foamed materials include plastic foams, for example polyurethane foam, polyethylene foam, polypropylene foam, a foam of an ethylene - propylene copolymer, phenolic foam, or any other plastic foam known to the person skilled in the art may also be used.
• Suitable polymeric foams exist as closed cell, syntactic cellular polymer compositions, which in a preferred embodiment have a density of about 20 to 300 kg/m 3 . The density of the foam may be graduated, with the region immediately adjacent to the attachment point having the highest density.
• foamed materials include materials comprising polymeric or ceramic hollow microballoons or hollow
• the foam has a glass transition temperature (T g ) equal or less than 0°C with a change in the ratio of the loss modulus to the stored modulus of no more than 50% from the median value measured over the temperature range of from about -20°C to about 50°C. This ensures that the foam has good impact resistance over its operating range.
• T g glass transition temperature
• the T g is less than -10 and more preferably less than - 20°C.
• the change in tan delta between about -20°C to about 50°C is preferably no more than 40% and even more preferably no more than 30%.
• the glass transition temperature (T g ) is preferably determined by Dynamic Mechanical Thermal Analysis (DMTA) in accordance with ASTM D4065-93, adapted to measure T g at the onset of the drop in the elastic modulus.
• DMTA Dynamic Mechanical Thermal Analysis
• the core layer of the impact resistant portion is made of a closed cell polyethylene foam as such foams have excellent energy dissipating properties.
• the distal portion may be made of a metal, for example aluminium.
• the distal portion may also be made of a metal alloy, preferably steel, more preferably stainless steel or weathering steel (also known as cor-ten steel), but may also comprise a fibre reinforced composite resin matrix or the distal portion may also be of a laminate construction of which preferably at least one layer is a fibre reinforced composite resin matrix.
• the laminate comprises an outer layer, a core layer and an inner layer (e.g. sandwich construction).
• the thickness of the laminate construction is preferably between 20 and 30 mm.
• At least one layer of the laminate construction comprises a fibre reinforced composite resin matrix. More preferably, at least one layer of the laminate construction is made of the fibre reinforced composite resin matrix. Even more preferably, the laminate comprises an outer layer, a core layer and an inner layer, whereby the inner and outer layer of the laminate construction comprises the fibre reinforced composite resin matrix. Even more preferably, the laminate comprises an outer layer, a core layer and an inner layer, whereby the inner and outer layer of the laminate construction is made of fibre reinforced composite resin matrix.
• the composite resin material is reinforced with fiber or yarn.
• Suitable yarns include aramid fibers, E glass or S-glass fibers, fibers of high tenacity polyester and yarns comprising ultra-high molecular weight polyethylene fibers. These type of yarns or fibers have a good combination of high strength and modulus of elasticity which may them particularly suited to withstanding impacts.
• Suitable Yarns are aramid fibers, for example sold under the trade name KevlarTM and TwaronTM.
• Yarns comprising high tenacity polyester fibers are for example sold under the trade name VectranTM
• yarns comprising ultra-high molecular weight polyethylene fibers are for example sold under the trade name DyneemaTM and SpectraTM.
• the fibers or yarn may form part of a woven or non-woven fabric.
• the fiber or yarn preferably has a tensile strength of at least 0.5 GPa, more preferably at least 1.2 GPa, even more preferably at least 2.5 GPa and yet even more preferably at least 3.0 GPa.
• the fibers or yarn are preferably arranged in a plurality of layers, more preferably in at least 3 layers.
• the adjacent layers having fibers or yarn which are disposed an angle of at least 30°. More preferably, the adjacent layers have fibers or yarn disposed an angle of about 90°.
• Each layer is preferably embedded into a matrix comprising a thermoplastic or thermosetting resin matrix.
• thermoplastic resins are resins which can be heated and softened, cooled and hardened a number of times without undergoing a basic alteration
• thermosetting resins are resins which cannot be resoftened and reworked after molding, extruding or casting and which attain new, irreversible properties once set at a temperature which is critical to each resin.
• the fiber reinforced composite resin matrix preferably has a modulus of at least 50 MPa and preferably at least 80 MPa.
• the rigidity of this matrix is especially suited to rigid fibers such as the glass reinforcing fibers.
• the amount of fibre, in particular glass fibre, in each of the fiber reinforced composite resin matrix layer is preferably at least 40 volume%.
• the core layer preferably comprises a polymeric material that provides a relatively light means of providing rigidity to the wall.
• the polymeric material is preferably a polymeric foam as this provides a low density structural material.
• Suitable foamed materials include metal foams, for example aluminum foam, glass foams or plastic foam, for example polyester foam, such as polyethylene terephtalate foam, polyvinyl chloride foam, polyurethane foam, polystyrene foam, polyethylene foam, polypropylene foam, a foam of an ethylene - propylene copolymer, phenolic foam, or any other plastic foam known to the person skilled in the art. may also be used.
• the core layer may also be made of:
• phenolic/aramid fiber mix such as Nomex® Paper which may be used to form a honeycomb core
• balsa wood core typically 100-240 kg/m3
• the core layer of the distal portion comprises a polyester foam, such as polyethylene terephtalate foam, or a polyvinyl chloride foam.
• the core layer may be made of essentially one piece and of essentially one material.
• the core layer may be made also of reinforced fibrous material. It is however also possible to use a core layer comprising two or more superimposed layers. The two or more superimposed layers may be made of the same or a different material. Suitable two layer systems are described in US 4101704. One or more layers may be made of reinforcing fibrous material.
• the reinforcing fibrous material may be the same or different material as used in the outer and/or inner layer.
• the core layer may comprise structural support inserts to improve the impact resistance of the wall.
• the inserts may be honeycomb-like or wave-like structure. Preferred inserts are further described in EP1596024, particularly Figures 2 to 6 and text referencing thereof.
• the inner layer functions as a skeletal frame connecting the proximal portion and the distal portion together.
• the skeletal frame forms part of the same panel as the proximal and distal portions.
• the skeletal frame is able to receive more than one panel, each panel comprising an outer layer and a core layer as previously described.
• the skeletal frame is able to directly transfer energy to the core layer of the distal portion, thereby reducing vibration compared to panels which form the entire cross-section of the wall, roof or floor.
• the modulus of elasticity of the distal portion is preferably at least 1 GPa, more preferably at least 10 GPa, even more preferably at least 15 GPa, most preferably at least 20 GPa.
• a high resistance to bending results in the distal portion having sufficient rigidity to structurally support the impact resistant portion, such that the container as a whole satisfies the tests described in section 6 of ISO 1496-1 (fifth edition) and/or tests described in section 8 of ISO 1496-2 (fifth edition).
• the impact resistant panel covers a geometric portion of the panel which has the highest risk of impact.
• the impact resistant panels preferably extend to a radius of more than 300 mm, more preferably more than 500 mm, even more preferably more than 750 mm and yet even more preferably more than 1000 mm.
• the impact resistant portion is preferably no more than 2500 mm and more preferably no more than 2000 mm.
• the impact resistant portion covers less than 50% of the surface area of the wall, roof or floor, more preferably less than 30% and even more preferably less than 10% and yet even more preferably less than 5% of the area of the wall, floor or roof of the container.
• the impact resistant panels extends from the attachment fitting containing the attachment means (e.g. apertures to receive a hook from a handling device) towards the closest adjacent end corner fitting.
• the panel is preferably rectangular with a length to width ratio of preferably more than 1.5 to 1 , with the length measured in the direction of the closest adjacent attachment fitting.
• the distal portion comprises one or more panels which separate the proximal portions adjacent to each attachment fitting.
• the distal panels represent at least 50%, more preferably at least 70% and even more preferably at least 90% and yet even more preferably at least 95% of the area of at least the wall, floor or roof of the container.
• the impact resistant panel and the distal panel are preferably attachable and detachable to the frame to enable more efficient and effective repairs to the panel(s).
• At least the wall, roof or floor comprises at least four, more preferably at least six, even more preferably at least eight and yet even more preferably at least ten panels.
• at least the wall, roof or floor comprises less than twenty and more preferably less than fifteen panels.
• the more panels there are the more attachment means are required to connect the impact resistant and distal portions together.
• Each attachment means is a source of energy dissipation and therefore the greater the number of attachment means the more effective the energy dissipation is from the impact zone.
• An energy dissipation means is also preferably integrated into the attachment means of the panels to the frame.
• the means to attach and/or seal the panels to the frame comprises a polymeric composition having a modulus of less than 50 MPa and preferably less than 25 MPa or a resilient coil (e.g. spring load bolts).
• Detachable for the purposes of the present invention, means that the layers in question may be separated such that the layers do not show either permanent deformation or abnormality which will render it unsuitable for use, consistent with the pass criteria used in ISO 1496-1. (i.e. the layers can be taken apart and then reused).
• the containers of the present invention are preferably nominal 10, 20, 30, 40 or 45 foot containers.
• the container is a nominal 45 foot container, as these containers are particularly used for transportation by road, in which the frequency of handling (and thus risk of damage) is often greater than in other modes of transport.
• Figure 1 is a longitudinal cross-sectional view of a container roof according to one embodiment of the present invention.
• Figure 2 is a top view perspective of the roof comprising the impact resistant portion adjacent the attachment point and a portion distal from the attachment point.
• Figure 3 is a top view perspective of the roof comprising the impact resistant portions adjacent the attachment points
• a vertical frame support 10 comprising an ISO corner fitting 20 (Fig 1 ); 20, 21 , 22, 23 and 24 (Fig 2); 21 ', 22', 23', 24', 25', 26', 27' (Fig 3).
• the frame is preferably made out of a suitable material, such as steel.
• the ISO fitting is a detachable fitting as described in US 7,059,488, in particular Figures 2 to 5 illustrated therein.
• the frame is preferably connected to impact resistant panels 30 which is immediately adjacent, and preferably abutting, the frame.
• the impact resistant panel is connected to the frame by means of a spring loaded bolt 40, which secure the panel from above and/or below. Further attachment points may be made from the frame directly into the core layer.
• the impact resistant panel is a sandwich type panel, comprising an outer layer 50, a core layer 60 and an inner layer 70.
• the roof preferably comprises an impact resistant panel 30 each end of the roof.
• the impact resistant panels are connected to central panels 100.
• the connection between the panels preferably enables the panels some degree of vertical vibration through the use of resilient elastomeric seals 1 10 and/or spring loaded fasteners, such as spring loaded bolts.
• the core layer may connect to the adjacent core layer by means of a tongue and groove joint 130, which assists in reducing the degree of vertical movement in adjacent panels and improves the dampening efficiency of the roof as a whole.
• Other suitable joints are described in US 5,030,488.
• impact resistant panels (30') are present in the regions surrounding each of the attachment point (20', 21 ', 22', 23', 24', 25', 26', 27').
• the impact resistant panels are connected to central panel 100'.
• the impact resistant panels are connected to central panel 100'.
• the dimensions of the impact resistant panels are 572mm*600mm for the regions surrounding the attachment point 20', 21 ', 22', 23'; and 590mm*600mm for the regions surrounding the attachment point 24',25', 26', 27'.
• the central panels 100/100', which are distal from the attachment points preferably comprise an outer 50', core 60' and inner 70' layer.
• the central panels 100/100' may also be of a metal or metal alloy, such as steel.
• the modulus of elasticity of the distal portion is at least 20% greater than the modulus of elasticity of the impact resistant portion. .
• the containers of the present invention may also be suitable used and/or modified for other applications, such as building construction.
• Both the top and bottom composite skins of the rigid sandwich panels are made of 2 layers of triaxial (-45/90/+45) fiberglass commercially available from Saertex, Germany impregnated with vinyl ester resin (ATLAC 430, commercially available from DSM Composite Resins, Switzerland) resin. Total thickness of the fiberglass reinforced skins is 1 ,8 mm.
• Two sets of rigid sandwich panels are produced; one series is manufactured by using poly vinyl chloride (PVC) 80 kg/m 3 25 mm thick foam core (brand name C70.75, commercially available from Airex, Switzerland) and the other series by using polyethylene terephthalate (PET) 100 kg/m 3 25 mm thick foam core (brand name T90.100, commercially available from Airex, Switzerland).
• PVC poly vinyl chloride
• PET polyethylene terephthalate
• T90.100 commercially available from Airex, Switzerland
• Both series of rigid sandwich panels are manufactured by hand lamination, where fiberglass mats are impregnated with vinyl ester resin by hand; foam core is placed in between the two "wet” fiberglass skins so that the top and bottom surfaces of the core material are also impregnated with vinyl ester resin.
• the panels are then left for 24 h at room temperature for the resin to cure; afterwards they are placed in an oven for post-cure at 60°C for 24 h. '
• the rigid sandwich panels are preferably produced in a two-step process; first the composite skins are manufactured by preferably continuous lamination where fiberglass triaxial mats are impregnated with vinyl ester resin in a continuous way. After the resin is cured, rigid foam core materials are bonded to the composite skins by using a polyurethane adhesive of which the final strength can be reached after a number of days. Materials of the flexible sandwich panels
• Both the top and bottom skins of the flexible sandwich panels are made of castable polyurethane (PU) (Bolipur 160, commercially available from Bolidt, the Nethlerlands); the PU skins are produced by mixing part A and part B with a mix ratio of 86: 14 by weight. Both top and bottom PU skins are 2 mm thick.
• PU castable polyurethane
• the core of the flexible sandwich panels is made of closed-cell polyethylene (PE) foam 20 mm thick.
• PE closed-cell polyethylene
• a one-component liquid primer is applied on the top and bottom surfaces of the PE foam and left to cure for 24 h at room temperature; as such the PU mix of part A and part B is poured on the foam surfaces and evenly spread out. The system is left to cure at room temperature for 24 h.
• Total thickness of the flexible sandwich panels is approximately 24 mm.
• Rigid sandwich panels made with PVC and with PET foam cores are tested in 4-point bending (apparatus used is of Zwick with a 20 kN load cell). Sample length is 1200 mm and width is approximately 62 mm; the distance between the testing supports is 1000 mm while the distance between the two loading members is 180 mm.
• E-modulus in bending of rigid sandwich panels made with PVC foam core is 5,35 kN/mm 2
• E-modulus in bending of rigid sandwich panels made with PET foam core is 5,28 kN/mm 2
• E-modulus in bending of flexible sandwich panels is 0,00278 kN/mm 2 .
• Charpy impact tests are performed with rigid sandwich panels made with PVC and PET foam cores and with flexible sandwich panels.
• the sample width is approx. 15 mm; and the sample thickness is approx. 28 mm.
• the flexible sandwich panels are capable of withstanding an elastic deformation greater than 40 mm (this value is determined by the 3-point bending tests where a flexural load is applied and the elastic deformation is recorded; once a value of deformation of 40 mm is obtained, the load is removed and the hysteresis behaviour is recorded: almost immediately the panels come back to their original shape with close to no deformation, therefore a deformation of at least 40 mm is "elastic", since it is not a permanent deformation ; after the load is removed they return to their original shape with no damage).
• the rigid panels are not capable of withstanding such large elastic deformations and they break at much lower deformations.

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  • 2010-12-10 WO PCT/EP2010/069364 patent/WO2011070147A1/en active Application Filing
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