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
  • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
  • B65D81/02—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents specially adapted to protect contents from mechanical damage
  • B65D81/03—Wrappers or envelopes with shock-absorbing properties, e.g. bubble films

Definitions

• This invention relates to a flexible wrap, particularly for packaging, and a method for its production.
• Wraps are known formed from two flexible films of air-impermeable material welded together face to face along closed iines defining a plurality of small air-filled blisters forming a sort of cushion or bubbles able to protect delicate objects wrapped in the wrap against impact and scratching.
• This bubble wrap is formed by making a flexible extensible film adhere to a roil, the lateral surface of which comprises a plurality of generally hemispherical cavities connected to a suction pump.
• the extensible film heated and made to adhere to the inner surface of said cavities, is then welded face to face to a second flexible film with which the first forms hemispherical blisters, within which air remains trapped.
• this bubble wrap is formed from continuous film and is hence itself continuous and can be wound into reels, of dimensions depending only on its physical bulk.
• a drawback of this known bubble wrap is that its production requires very complicated equipment and generally laborious machining of the rolls, together with costly heating and suction systems, all of which substantially affect the final cost of the product obtained.
• a further drawback is that the total thickness of the wrap produced is substantially equal to the height of the blisters, which varies from 2 to 5 mm, hence in the case of 5 mm blisters a reel of about 60 cm diameter contains less than 60 metres of wrap, with obvious and often serious space requirement problems due to the considerable volume/weight ratio.
• Flexible wraps are also known consisting of a layer of expanded material having a prefixed thickness. For their production they require less complex techniques and equipment which have lower costs for realizing the final product, but they don't solve the drawback of space, due to the high volume/weight ratio.
• An object of the invention is to provide a flexible wrap for packaging, provided over its entire surface or part of it with elasticaliy extensible material acting as protective cushion for the objects wrapped in said wrap.
• a further object of the invention is to provide a flexible wrap for packaging which prior to its final use is of small overall size, such as to virtually totally eliminate all the current problems connected with its storage and transport from the place of utilization.
• a further object of the invention is to improve the performance obtainable from flexible wraps by also providing it with thermal, acoustic and electromagnetic barrier properties, together with increased protective properties to the extent of making it multi-purpose.
• Figure 1 shows schematically a reel of wrap according to the invention in the embodiment of a bubble wrap before energy administration
• Figure 2 shows it after energy administration
• Figure 3 shows partially it in enlarged longitudinal section before energy administration
• Figure 4 shows it after energy administration
• Figure 5 shows schematically a method for producing the wrap of the invention
• Figure 6 shows partially in enlarged longitudinal section a portion of a modification of the wrap of the invention, before energy administration
• Figure 7 shows it after energy administration
• Figure 8 shows it in a further modification before energy administration
• Figure 9 shows it after energy administration
• Figure 10 shows a reel of wrap according to the invention in a second embodiment with continuous thickness before energy administration
• Figure 11 shows it after energy administration
• Figure 12 shows partially it in enlarged longitudinal section before energy administration
• FIG. 13 shows it after energy administration
• Figure 14 shows it in a modification of this second embodiment before energy administration
• Figure 15 shows it after energy administration
• Figure 16 shows it in a second modification of this second embodiment before energy administration
• Figure 17 shows it after energy administration
• the flexible wrap of the invention in the "bubble" embodiment consists of two flexible films 2,4 impermeable to air or other gas, and defined hereinafter as the support film 2 and the extensible film 4.
• the support film 2 can for example consist of polyester, high density polyethylene (HDPE), paper with polyester, polyethylene, polypropylene or polyvinylchloride backing, or aluminium with polyester, polyethylene or polypropylene backing.
• the total thickness of the support film 2 varies preferably from 20 to 100 ⁇ , depending on the type of material and of the performance required of the bubble wrap, although different thickness can be used with particular materials and for particular applications.
• the extensible film 4 of much greater deformability than the support film 2 is preferably of low density polyethylene (LDPE), polyester or polypropylene, depending on the nature of the support film 2 and on the visco- elastic and Theological characteristics of the extensible film 4.
• LDPE low density polyethylene
• polyester or polypropylene depending on the nature of the support film 2 and on the visco- elastic and Theological characteristics of the extensible film 4.
• the thickness of the extensible- film 4 varies preferably from 20 to 50 ⁇ but again in this case different thickness can be used with particular materials and for particular applications.
• the two films 2, 4 are joined together along closed lines defining small blisters or cells 6, which can be of any size and any shape, and in particular be circular, polygonal or elongate.
• the two films 2, 4 can be joined together by thermal, high frequency, ultrasonic or infrared welding, or by using suitable adhesives compatible with the film constituent materials.
• suitable adhesives are preferably epoxy, phenolic, acrylic, formaldehyde, anaerobic, cyanoacrylate, elastomeric, silicone, polyurethane, polysulphide or inorganic resins, or non-chemical resins providing physical-mechanical adhesion.
• Each of the blisters 6 houses in its interior a substance 8 which following administration of energy expands to inflate the blister.
• the substance 8 is for example of sublimable type, ie is able to pass from the solid state directly to the gaseous state when its transformation temperature is attained.
• sublimable substance examples include "sublimation dyes”, isoquinone- 5-carboxynitrile, some trioxanes and siloxanes, and p-dichlorobenzene, which all have the property of passing from the gaseous state on attaining the transformation temperature, which varies from about 53°C for p- dichlorobenzene to about 135°C for isoquinone-5-carboxynitrile, and at a rate which is lowest for p-dichlorobenzene and highest for isoquinone-5- carboxynitrile.
• sublimation dyes isoquinone- 5-carboxynitrile, some trioxanes and siloxanes
• p-dichlorobenzene which all have the property of passing from the gaseous state on attaining the transformation temperature, which varies from about 53°C for p- dichlorobenzene to about 135°C for isoquinone-5-carboxynitrile, and at a rate which is lowest
• the sublimable substance 8 possibly already enclosed within an expandable material (for example microspheres), is applied to the support film 2 preferably by stamping it thereon under register control such as to involve only the regions intended to form the blisters 6 and leave free thin bands bounding said blisters, at which the support film 2 and the extensible film 4 are to be joined together.
• an expandable material for example microspheres
• FIG. 5 shows schematically the process for producing the bubble wrap according to the invention.
• the support film 2 unwound from a reel 10 receives the applied sublimable substance 8 in a stamping station 12 under register control, and is then joined in a welding station 14 to the extensible film 4 unwound from a reel 16. If the two films 2 and 4 are joined together by gluing instead of by welding, a second station is provided (not shown on the drawings) in which the adhesive is applied to the support film 2 and to the extensible film 4 preferably under register control.
• the composite film 18 obtained in this manner is then wound into a reel 20 to be then stored and/or sent to its place of use.
• the reel 20 obtained although of dimensions substantially equal to those of usual transportable reels, contains a composite film of length considerably greater than that of traditional bubble wrap.
• a reel of 60 cm diameter contains about 1900 metres of bubble wrap having a thickness of 150 ⁇ .
• the composite film 18 In the location in which the composite film 18 is used, it is subjected to energy administration, for example heat, which causes the substance 8 contained in the blisters to expand and inflate the blisters, transforming them into bubbles. During this stage the administered heat also causes the extensible film to soften, so facilitating stretching.
• energy administration for example heat
• the substance 8 contained in the blisters to expand and inflate the blisters, transforming them into bubbles.
• the administered heat also causes the extensible film to soften, so facilitating stretching.
• energy of other types can be administered depending on the type of expandable substance and/or any activators used for the sublimation process.
• the expandable substance confined within the closed blisters may be of foaming type, ie able to increase in volume following a chemical reaction by expansion agents which by increasing in volume cause cells to form having walls which solidify by cross-linking, polymerization or phase transition as in normal manufacturing processes for expanded materials or foams.
• expansion agents which by increasing in volume cause cells to form having walls which solidify by cross-linking, polymerization or phase transition as in normal manufacturing processes for expanded materials or foams.
• the energy is administered directly to the expansion agent which on being heated or activated initiates gas formation with consequent volume increase and structural change to a solid material.
• Usable polymer matrices are liquids, including high viscosity liquids, or gels, such as formaldehydes or epoxy, polyester, polyurethanic, acrylic resins.
• the expansion agent can be for example sodium bicarbonate, azodicarbonamide or its derivatives, benzene suplphonitryl hydrazide, tetra amines, benzene sulphonylhydrazide, urea derivatives or organic acids.
• sodium bicarbonate this reacts with water in accordance with the reaction.
• Reaction inhibitors and other known additives to prevent the substance being transformed into gas or expanding below certain values of administered energy can be mixed with the expansion agent to better control the determined expansion of the expanding substance.
• the expansion agent is applied to the support film 2 preferably by stamping it thereon under register control, the extensible film 4 then being applied to the support film 2 by thermowelding along the edges of the shapes previously stamped under register control.
• Each blister could also contain in its interior more than one expandable substance, with different characteristics, and each activated by a different type of administered energy. In this manner one or other substance can be expanded simply by varying the type of activation energy, so that the inflated blisters obtained are filled with expanded substances of different characteristics suitable for the particular use to which the wrap is to be put.
• the expanded substance contained within the inflated blisters can offer resistance to impact, to light, to moisture, to noise, to electromagnetic waves and to other pollutant agents.
• the wrap of the invention can consequently be considered a multi-purpose bubble wrap.
• the expandable substance confined within the closed blisters is contained in microcapsules 22, each comprising a membrane of extensible material and an agent which expands on command, consisting for example of particular hydrocarbons such as isobutane, isopropane and their mixtures.
• the expandable membrane can consist for example of vinylidene chloride and acrylonitrile copolymers, or acrylonitrile copolymers.
• microcapsules 22 may be directly applied to the support film 2
• each capsule can contain more than one type of expandable substance in its interior, to be selectively activated by administering different types of energy.
• the microcapsules may have the membrane tearable following energy administration.
• they comprise one of the two components of the expandable substance, which component, following the break of the membrane, comes into touch with the other component forming the matrix inside which the microcapsules are placed and which, following this touch, cause the expansion.
• the microcapsules 22 are directly applied to the support film 2, the same matrix which forms the second component of the expandable mixture, may be provided with adhesive properties in order to couple the two films 2 and 4 before and after the expansion process.
• this substance doesn't affect localized areas of the wrap but the entire surface thereof.
• the wrap which after its realization is very thin (see Figure 10) increases of volume, after energy administration, in the areas where this is required. If energy is administered to the entire surface of the wrap, the entire wrap increases of thickness (see Figure 11 ) whereas if this energy administering occurs under register control (for example by diaphragm or filters) only the affected areas will expand.
• the production of wrap according to the invention in this embodiment may occur both by extruding the plastic material forming the film and which already houses inside it the expandable substance (see Figures 12 and 13), if necessary housed in microcapsules 22 (see Figures 14 and 15), and by applying such an expandable substance 8 between the two films 2 and 4 already made (see Figures 16 and 17).
• the expandable substance may be housed in microcapsule 22 (see Figures 18 and 19) and may consist of one or more different kinds and the energy or the different kinds of energy may be administered over the entire surface of the wrap or, under register control, over the only parts where the expansion should be caused.
• the blisters can now contain not only air but also substances of particular physical characteristics (thermal, acoustic, mechanical, etc.),

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Laminated Bodies (AREA)
• Packages (AREA)
• Wrappers (AREA)
• Buffer Packaging (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11424450

Family Applications (1)

Country Status (8)

Cited By (19)

Families Citing this family (1)

Citations (5)

• 1999
  • 1999-05-18 IT IT1999VE000023A patent/IT1311791B1/it active
• 2000
  • 2000-05-18 AT AT00935063T patent/ATE247045T1/de not_active IP Right Cessation
  • 2000-05-18 ES ES00935063T patent/ES2204608T3/es not_active Expired - Lifetime
  • 2000-05-18 DE DE60004524T patent/DE60004524T2/de not_active Expired - Fee Related
  • 2000-05-18 WO PCT/EP2000/004502 patent/WO2000069747A1/en active IP Right Grant
  • 2000-05-18 AU AU50681/00A patent/AU5068100A/en not_active Abandoned
  • 2000-05-18 EP EP00935063A patent/EP1185466B1/en not_active Expired - Lifetime
  • 2000-05-18 DK DK00935063T patent/DK1185466T3/da active

Patent Citations (5)

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