GB2322844A

GB2322844A - Protective Bag

Info

Publication number: GB2322844A
Application number: GB9704663A
Authority: GB
Inventors: John Alexander Matwiejew
Original assignee: JIFFY PACKAGING CO Ltd
Current assignee: JIFFY PACKAGING CO Ltd
Priority date: 1997-03-06
Filing date: 1997-03-06
Publication date: 1998-09-09
Also published as: GB9704663D0

Abstract

A protective bag has walls (6, 8, fig. 2) made from an outer layer 20 with an intermediate layer of bubble wrap 24 laminated to it and a further layer of bubble wrap 26 attached to the intermediate layer 24. The outer layer 20 may be a sheet of heavy duty plastics material or a sheet of Kraft paper with an inner surface layer of polyethylene 22 to allow lamination of the outer sheet 20 to the bubble wrap 24 by heat sealing and pressure. The bubble wrap sheets 24, 26 may be attached together by adhesively bonding at discreet locations prior to laminating to the outer layer, or the outer layer may be laminated to the first sheet of bubble wrap 24 prior to attaching the second sheet 26. The lamination operation may be carried out prior to formation of the bag, or the cushioning material may be placed into a preformed envelope and passed between heated bars to join them together. Laminating the layers of bubble material to the outer layer provides an increase in the stiffness of the bag.

Description

PATENTS ACT 1977 WL/A9099GB - JIFFY PACKING LIMITED TITLE: Improvements Relating to Protective Bags Description of the invention This invention is concerned with improvements relating to protective bags and in particular, with the provision of a cushioning material for use in the manufacture of a protective bag. The term "bag" is used here generically to include, not only larger bags, but also smaller bags and envelopes in which an article may be protected (e.g.) during transportation.

There is a large and increasing demand for protective bags, particularly to protect fragile articles, for example, electronic components or components of a fragile nature such as glass, during transportation such as postage.

One conventional protective bag comprises twin layer walls, having there between, a cushioning material provided by macerated paper. Another conventional protective bag comprises a single layer wall having secured to the inside, a cushioning material of the kind known as "bubble-wrap".

A conventional bubble material comprises a base layer, conveniently in the form of a sheet of plastic film and an upper layer provided by a forming operation, such as vacuum forming, with a plurality of pockets, the two layers being secured together in a manner such as to retain air trapped within the pocket to provide "bubbles" which, in conjunction with the flexibility of the film used in the manufacture, provide a cushioning means. Conventionally base and upper layers are formed by polyolefin materials, such as polyethylene or polypropylene, having a density and thickness to provide on the one hand, sufficient elasticity of the walls of the pocket to provide adequate cushioning, whilst on the other hand providing sufficient strength.

Increasingly there is a demand for bags having not only greater cushioning capability but also greater strength. For example, a problem has been encountered in conventional protective bags comprising as cushioning means, bubble material, in that bubbles may be collapsed relatively easily by penetration, allowing moisture or other substances, which may deleteriously affect the article being transported, to egress within the bag.

According to this invention there is provided a protective bag the walls of which comprise an outer layer, an intermediate layer of bubble material laminated to the outer layer and an inner layer of bubble material secured to the intermediate layer.

By laminating the intermediate layer of bubble material to the outer layer, increasing "stiffness" of the bag is provided, which is improved further by the provision of the inner layer being secured to the intermediate layer.

According to this invention there is also provided a method of manufacture of a protective bag in which an outer layer is laminated to a first layer of bubble material, to which is also secured, on the opposite side, a second layer of bubble material.

The two layers of bubble material may be secured together by adhesively bonding the layers of bubble material together at discrete locations, or the two layers may be laminated together, e.g. during forming thereof.

The outer layer may be laminated to the first layer of bubble material either prior to the adhesively securing thereto of the second layer, or may be laminated to a layer comprising the first and second layers of bubble material.

The lamination operation may be carried out prior to formation of the bag, or may be carried out subsequent to formation of the bag.

Thus, a "double" layer of bubble material - that is two layers of bubble material secured together either by adhesive or by lamination - may be laminated to the outer layer in sheet form, the outer layer comprising a layer of heat softenable plastics material, such as polyethylene, which may be effectively bonded to the double material by the use of heat and pressure.

Thus, the outer layer and the bubble layer may be passed between rollers, which together with the use of heating means enables the two layers to be laminated together.

Alternatively the cushioning material may be inserted into an envelope and the envelope pressed between heated bars which cause the outer layer and the cushioned layer to become fused together.

The outer layer may comprise heavy duty paper, such as that conventionally referred to as "Kraft", such as of 50-lSOgms weight, conveniently being provided on one side thereof with a thin layer of polyethylene, which serves as an adhesive material by which the cushioning material may be laminated thereto.

Alternatively the outer layer may be afforded by a sheet of heavy duty plastics material, to which the cushioning layer is adhered directly.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of a padded bag and various methods of manufacture thereof, which have been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings : Figure 1 is a schematic perspective view of the bag which is the preferred embodiment of this invention; Figure 2 is a sectional view on an enlarged scale, taken on the line 2-2 of Figure 1; Figure 3 is an enlarged view of part of one wall of the bag shown in Figure 2; Figure 4 shows schematically one stage in a method of manufacturing the bag; Figure 5 shows schematically a stage in the manufacture of a bag by an alternative; and Figure 6 shows a view of part of Figure 5.

The bag which is the preferred embodiment of this invention is generally rectangular, comprising two composite walls 6,8 sealed together around a peripheral margin 10, in conventional manner. The bag has an opening 12 through which articles may be inserted into the bag and a closure flap 14, which may be folded onto the layer 6 and secured thereto by an adhesive band 16.

Each of the walls 6, 8 comprises an outer layer 20 (Figure 3) which in the preferred embodiment is provided by Kraft paper of about 120gms in weight, provided on an interior surface thereof with a layer 22 of polyethylene.

Laminated to the layer 20, conveniently by the use of the layer 22, is a first layer 24 of bubble material and secured to the layer 24 on the opposite side thereof is a second layer 26 of bubble material. The layer 26 may be secured to the layer 24 by lamination, or by the use of adhesive, or may be formed integrally with the layer 24, the criterion being two layers of bubbles are provided on the inside of the layer 20.

It has been found that laminating the layer 24 to the layer 20 significantly increases the stiffness of the bag, providing a high degree of protection to articles located therein, whilst the provision of the second layer 26 of bubble material significantly reduces the tendency of the article, such as sharp corners thereof, penetrating to the outer layer 20.

The bag may be manufactured by a method involving the bringing together of two composite layers A, B, the composite layer A comprising the outer layer 20 together with the layer 22 of polyethylene adhesive, the composite layer B being afforded by the layers 24, 26 of bubble material. The two layers of bubble material may have been secured together ab initio, or by the use of spot welding, or by the use of adhesive, or heat welding, as may be convenient.

A radiant heater 30 is provided to heat the layer 22 of adhesive of the Kraft 20, and as the two layers A, B are passed around the rollers 32, 34, they are pressed together, causing the layer 24 of bubble material to become laminated to the layer 20 by the layer 22.

The composite sheet is then utilised to provide one of the two walls 6, 8 of the bag, conveniently being cut as necessary and secured together around said peripheral margin 10 by the use of heated rollers and/or heated bars, in conventional manner.

Alternatively, the bag may be formed by the manufacture of an open bag comprising walls 6, Sa, each wall comprising an outer layer 20a of Kraft, carrying on the inside thereof a layer 22a of polyethylene, into which an envelope comprising contiguous layers 24i, 26a of bubble material is inserted.

The bag is then drawn between heated plates 40, 42 which heat the outer layer of Kraft of both walls, causing the layer 22a of polyethylene thereof to soften and adhere to the layer 24a of bubble material, causing the layer of 24a of bubble material to become laminated to the outer layer 20a of Kraft.

It will, however, be appreciated that other methods of manufacture may be utilised to manufacture a bag in accordance with this invention.

Whilst the bag which is the preferred embodiment of this invention comprises an outer layer 20 of Kraft, to which a layer 22 of polyethylene is applied, the outer layer may be provided by a layer of plastics material, such as polyethylene, to which the intermediate layer 24 of bubble material may be laminated direct.

Claims

1 A protective bag the walls of which comprise an outer layer, an intermediate layer of bubble material laminated to the outer layer, and an inner layer of bubble material secured to the intermediate layer.

2 A method of manufacturing a protective bag in which an outer layer is laminated to a first layer of bubble material, to which is also secured, on the opposite side, a second layer of bubble material.

3 The invention according to claims 1 or 2 wherein the two layers of bubble material are secured together by adhesively bonding the layers of bubble material together at discreet locations.

4 The invention according to one of claims 1 and 2 wherein the two layers of bubble material are laminated together during forming thereof.

5 The invention according to any one of the preceding claims wherein the outer layer is laminated to the first layer of bubble material prior to the adhesively securing thereto of the second layer.

6 The invention according to any one of claims 1 to 4 wherein the outer layer is laminated to a layer comprising the first and second layers of bubble material.

7 The invention according to any one of the preceding claims wherein the lamination operation is carried out prior to formation of the bag.

g The invention according to any one of claims 1 to 6 wherein the lamination operation is carried out subsequent to formation of the bag.

9 The invention according to one of claim 7 and 8 wherein a "double" layer of bubble material is laminated to the outer layer in sheet form, the outer layer comprising a layer of heat softenable plastics material which may be bonded to the double layer by the use of heat and pressure.

10 The invention according to claim 9 wherein the outer layer of the bubble layer is passed between rollers, which together with the use of heating means, enables to two layers to be laminated together.

11 The invention according to claim 9 wherein the cushioning material is inserted into an envelope and the envelope pressed between heated bars which cause the outer layer and the cushioned layer to become fused together.

12 The invention according to any one of the preceding claims wherein the outer layer comprises heavy duty paper having a weight of 50-lSOgms.

13 The invention according to claim 12 wherein the outer layer is provided on one side with a thin layer of heat softenable plastics material.

14 The invention according to any one of claims 1 to 11 wherein the outer layer is afforded by a sheet of heavy duty plastics material.

15 A protective bag constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

16 A method of manufacture of a protective bag, when carried out substantially as hereinbefore described with reference to the accompanying drawings.

17 Any novel feature or novel combination of features hereinbefore described and/or shown in the accompanying drawings.