IE44443B1 - Package construction - Google Patents

Description

This invention relates to a package construction.

An object of the present invention is to provide a package construction which encloses and protects for example absorbent volatile or fluid products packed therein during transit and storage without loss of contents whilst incorporating a feature which at the time of use allows permeation into or from the package to enable such contents to absorb evaporate or exude from within the package construction. The products contem10 plated include, but are not restricted to, dessicants, air fresheners,', insecticides, sauces, polishes, beverages, spices and the like.

According to the present invention there is provided a package construction comprising a flexible permeable web or pair of webs enclosed between a separate pair of impermeable flexible webs each of which is bonded at a peripheral surface portion only to a corresponding peripheral surface portion of the flexible permeable web or a corresponding peripheral surface portion of a respective one of the pair of flexible permeable webs, at least one of the bonds being a peelable bond.

The peelable bond referred to in this specification is characterised in that neither web is damaged during the separation. 4 4 4 3 - 3 The invention will now he described merely by way of example with reference to the accompanying drawings in which, Figure 1 is a cross-section, not to scale, through 5 a first package construction Figure 2 is a cross-section, not to scale, through a second package construction; and Figure 3 is a cross-section, not to scale, through a third package construction.

Referring now to Figure 1 there is shown a sachettype package 10 comprising a pair of separate flexible impermeable webs 43, 44 enclosing a permeable web 15.

Web 43 is of multi-ply construction and comprises, reading from the outside inwards, 37g/sq. m. cellulosic web such as glazed imitation parchment paper 11 1.5g/sq. m. aqueous based laminating adhesive 12 0.030 mm. impermeable aluminium foil 13 3g/sq. m. aqueous ionomer dispersion coating or layer 14 such as Adcote 3741 made by Morton Williams Ltd.

(Adcote is a Registered Trade Mark).

Web 44 is likewise of multi-ply construction and comprises, reading from the outside inwards, 37g/sq. m. glazed imitation parchment paper 20 1.5g/sq. m. aqueous based laminating adhesive 19 0.030 mm aluminium 13 2g/m Polyurethane adhesive 17 micron polyethylene film 16 -4.The porous web 15 is made of Tyvek spun bonded polyolefin (Tyvek is a Registered Trade Mark belonging to Du Pont).

In construction, the webs 43, 15 and 44 are placed on top of each other as shown in Figure 1, and heat sealing applied around the peripheral portions of the webs. Thus the dispersion coating 14 on web 43 is heat sealed to the web 15 to provide a peelable sealing of web 43 to web 15 at interface 50. Likewise, the polythene film 16 on web 44 is heat sealed to the web 15, at interface 51. But on at least one side there is left outside the heat-seal an unsealed area, 52, at which web 43 may be grasped to initiate its peeling from the sealed perimeter of the pack. It will be seen that a space 21 is provided between web 15 and the non-peelable web 44, wherein a product such as dessicant, air freshener, water softener, insecticide or the like is contained. On peeling off web 43 the permeable web 15 is exposed, thus permitting controlled permeation whilst retaining the product enclosed.

An advantage of using a heatsealed peelable bond is that when the permeable web is a fusible fibrous material (e.g. the spun bonded polyolefin referred to above), the peelable bond occurs only in areas where the fibres have fused together under the action of heatsealing, thus preventing fibre lift when the peelable face of the pack is removed. Hitherto, it has been found that undesirable fibre lift can occur if the web 15 is pre-laminated to web 43 to give an overall peelable bond.

Referring to Figure 2 there is shown a sachet-type package 22 comprising a pair of identical impermeable flexible webs 45 enclosing a permeable sachet 34. Each web 45 is of identical construction to web 43 of Figure 1, and the permeable sachet 34 is composed of two joined - 5 44443 webs each of identical construction to web 15 of Figure 1 and enclosing a space 35. The webs 45 are peelably heatsealed to the sachet 34 at the interfaces 32 and 33 in the same manner as web 43 is sealed to web 15.

Similarly peeling is initiated at the unsealed areas 53 and 54 outside the heatseal. Thus both webs 45 may be peeled off the sachet 34 without causing fibre lift from the sachet. Fibre lift can be undesirable if the sachet 34 or the pack of Figure 1 encloses a food commodity, or product for medical use.

By bringing the inner permeable webs and the outer impermeable webs together and heatsealing, the inner impermeable sachet and the peelable peripheral seals between the sachet and the impermeable webs can be formed in one operation.

The above mentioned structures are by way of example only and do not exclude the use of other suitable materials or package design.

Referring to Figure 3 there is shown a sachet-type package 60 comprising a pair of impermeable flexible webs 61,62 enclosing a permeable sachet 63. Web 61 is of identical construction to web 43 of Figure 1, and web 62 is of identical construction to web 44 of Figure 1. The permeable sachet 63 is composed of two joined webs each of identical construction to web 15 of Figure 1, and enclosing a space 64. Web 61 is peelably heat-sealed to the sachet 63 at interface 65 between the sachet and the web in the same manner as web 43 is sealed to web 15 in Figure 1. Web 62 is heatsealed to the sachet 63, in the same manner as web 44 of Figure 1 is sealed to web 15, to provide a permanent non-peelable sealing of web 62 to the sachet 63 at interface 66. But there is left outside the heat seal an unsealed area 67 at which web 61 may be grasped to initiate its peeling from the sealed perimeter of the pack. Thus web 61 may be peeled off the sachet, leaving the other side of the sachet protected - 6 by the non-pselable web 62.

The invention enables use to be made of coatings chosen for special properties, e.g. product resistance, which exhibit suitable bonding and subsequently peel5 ability between the permeable and impermeable webs on heat sealing, but which cannot readily be incorporated as adhesives to produce peelable laminates.

The use of whioh it is intended to put the package construction will dictate the type of laminate used, the overriding requirement being that the outer layer or layers of dual construction web can be peeled off to expose the permeable or porous inner layer.

Packages of the type described above can be produced on conventional packaging machinery with the permeable material being introduced by standard methods such as an interleaf, double-wound incorporated with the reel of impermeable materials, or from a separata reel stand.

Claims (13)

1. CLAIMS;1. A package construction comprising a flexible permeable web or pair of webs enclosed between a separate pair of impermeable flexible webs each of which is bonded at a peripheral surface portion only to a corresponding peripheral surface portion of the flexible permeable web or a corresponding peripheral surface portion of a respective one of the pair of flexible permeable webs, at least one of the bonds being a peelable bond.

2. A package construction as claimed in claim 1 wherein the pair of flexible permeable webs are joined together at their periphery to form a sachet.

3. A package construction as claimed in claim 1 or 2 wherein both impermeable webs are peelably bonded to the permeable web or each to a respective one of the pair of permeable webs.

4. A package construction as claimed in any preceding claim wherein the or each permeable web is coated so as to provide the peelable bonding.

5. A package construction as claimed in claim 4 wherein the peelable bond includes a heat seal between the or each impermeable web and the or each permeable web.

6. A package construction as claimed in claim 5 wherein the peelable bond includes between the or each impermeable web and the or each permeable web a resin layer activated by the heat seal.

7. A package construction as claimed in claim 6 wherein the resin layer is an aqueous ionomeric dispersion coating. -

8. 8. A package construction as claimed in anypreceding claim wherein the or each impermeable web is a laminate including an aluminium foil layer and a heat sealable coating on its inner face. 5

9. A package construction as claimed in claim 8 wherein the laminate includes a plastics layer. 10.' A package' construction as claimed in claim 8 or 9 wherein the laminate is faced externally with a cellulosic web.

10

11. A package construction as claimed in claim 10 wherein the cellulosic web is gla2ed imitation parchment paper.

12. A package construction as claimed in any preceding claim wherein the or each permeable web is 15 made from perforated, foraminous or porous plastics sheet.

13. A package construction substantially as herein described with reference to any one of the accompanying drawings.