GB2283007A

GB2283007A - Boil-in-bag sachet with tear-off strip

Info

Publication number: GB2283007A
Application number: GB9321494A
Authority: GB
Inventors: Peter Cools; Walter Gers; Dirk Verdoodt
Original assignee: Mars Inc
Current assignee: Mars Inc
Priority date: 1993-10-19
Filing date: 1993-10-19
Publication date: 1995-04-26
Also published as: ITRM940179U1; FR2711362A1; GB9321494D0; ITRM940179V0

Abstract

An easy-to-open boil-in-bag sachet (1) is provided with top (2) and bottom (3) transverse seals. Two lines of weakness (4) eg perforations on opposite sides of the sachet define a tear strip (5) in the sachet. The seals may be heat seals and may at one end comprise two distinct sealed bands (2, 6) with a fork slot (9) between them. A further, transverse, line of weakness (7) may be provided between the two upper seals. The sachets are preferably made by conventional form/fill/seal methods from a single web of water-permeable, heat-sealable thermoplastics film, such as a perforated polythene film in which lines of weakness have been made by rotating cutters (15, 16) prior to formation of the sachets. The top and bottom seals (2, 3) are preferably heat seals and the sachet preferably also comprises a transverse line of weakness (7) to initiate tearing of the tear strip (5), and a fork slot (9). <IMAGE>

Description

BOIL-IN-BAG SACHET The present invention relates to an easy to open boilin-bag sachet.

Boil-in-bag packages for food products are by now well known in the food packaging art. The packages are generally formed from thermoplastics materials and may be waterpermeable or water-impermeable depending on the food product concerned. Water-permeable boil-in-bag packages are used where rehydration of a food product inside the package is required, e.g. boil-in-bag rice or pasta. Water-permeable boil-in-bag packages are generally pouches or sachets formed from perforated or reticulated thermoplastic film.

GB-A-2117350 describes a water permeable boil-in-bag pouch suitable for cooking rice. The pouch is manufactured from a single, overlapped web of a perforated thermoplastic film and has two parallel, spaced-apart transverse seals at the top of the pouch, and another two parallel, spaced-apart transverse seals at the bottom of the pouch. There are also two spaced-apart longitudinal seals, and a longitudinally extending region of overlapped film between the two longitudinal seals. The extent of this film overlap between the longitudinal seals is at least 2.54 cm. The top and/or the bottom of the pouch is provided with a horizontal aperture of at least 1.9 cm in length within the region of the film overlap and between the two transverse seals.The horizontal aperture provides a fork slot that allows the boil-in-bag pouch to be lifted from the boiling water in which it has been cooked without tearing the thermoplastic film.

A difficulty with boil-in-bag packaging for use in the home is that the packaging must normally be opened while the contents are still hot. This entails awkward manipulation of the hot package with consequent risk of spillage and/or scalding of the person manipulating the package. Moreover, an additional utensil, such as a knife or scissors, is needed to open the package.

EP-A-0478812 describes an easy-to-open package for food products useful for boil-in-bag or microwave packaging.

The package comprises a sealed, flexible pouch with a thermoformed bottom web and a top web of mono-oriented material. A V-shaped precut is formed in the top web, whereby pulling on the precut results in tearing of the top web along the direction of orientation of the mono-oriented material, thereby opening the container. The precut is covered by an adhesive membrane patch which prevents leakage through the precut prior to opening the container, and which also operates as a starting pull tab for the opening.

EP-A-0499647 describes a similar package to that described in EP-A-0478812, except that the pull tab is formed as a precut in the upper one of two layers making up one part of the top web. This arrangement allows the adhesive membrane patch of EP-A-0478812 to be dispensed with.

The above packages are somewhat complex to manufacture and require the use of at least one web of mono-oriented plastics material. Accordingly, there is a need in the art for improved boil-in-bag sachets or pouches that are simple and inexpensive to make, and that are easy to open, even when hot, without the assistance of a knife or scissors.

The present invention provides a boil-in-bag sachet comprising top and bottom transverse seals and being further provided with two longitudinal lines of weakness on opposite sides of the sachet defining a tear strip in the sachet.

Preferably, the boil-in-bag sachet is water-permeable and contains a rehydratable food product. Preferably, the sachet is formed from a single web of film material, which is preferably a thermoplastics film material. Where a thermoplastics film material is used, the top and bottom transverse seals are preferably heat seals.

For easy opening of the sachet the lines of weakness preferably extend from the top to the bottom of the sachet, and preferably they also overlap at least in the region of the top and bottom seals.

Preferably, the two lines of weakness are substantially straight and substantially parallel. More preferably, the lines of weakness are straight, parallel to each other, and also substantially parallel to a longitudinal edge of the sachet (i.e. substantially perpendicular to the transverse top and bottom heat seals).

In that case the lines of weakness are equidistant from the said longitudinal edge of the sachet, and tearing along the lines of weakness detaches a rectangular tear strip from the sachet.

Preferably the lines of weakness are lines of perforations.

Preferably, the boil-in-bag sachet according to the present invention is also provided with a second transverse top seal longitudinally spaced from the first transverse top seal, and is further provided with a transverse line of weakness extending inwardly between the first and second top transverse seals from an edge of the sachet at least to one of the longitudinal lines of weakness. The transverse line of weakness is preferably a cut extending through the sachet. The transverse line of weakness is used to initiate tearing along the longitudinal lines of weakness.

In preferred embodiments a fork slot is also provided between the first and second transverse top seals, preferably near the centre of the sachet.

Preferably the boil-in-bag sachet according to the present invention is formed from a single web of material Preferably the sachet is formed from foraminous material, such as a perforated or reticulated web. This provides for maximum water permeability of the sachet, which is desirable for cooking rehydratable foodstuffs such as rice or pasta.

The sachet material may also be embossed. Typically, the sachet material comprises polyethylene or polypropylene film and has a base sheet thickness of less than 60 ssm, preferably less than 50 Mm, more preferably less than 40 4m and most preferably about 34 ssm.

The boil-in-bag sachets according to the present invention are preferably formed from a continuous web of thermoplastics material using conventional vertical form/fill/seal techniques well known to those skilled in the art and described, for example, in US-A-2145941. The equipment is modified to provide the lines of perforation in the finished sachet. Preferably, the lines of perforations are provided in the continous web of thermoplastic material before it is formed into the sachet. Preferably this is done by means of a rotating perforation knife forming a continuous line of perforations extending longitudinally along the continuous web of thermoplastic material.

An embodiment of the invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a side view of a boil-in-bag sachet according to the present invention; Figure 2 shows the same boil-in-bag sachet with the tear strip partially detached; Figure 3 shows the same boil-in-bag sachet with the tear strip completely detached; and Figure 4 shows a schematic view of the apparatus used to form the sachet of Figure 1.

Referring to Figure 1, the boil-in-bag sachet 1 is formed from a single web of a heat-sealable thermoplastics film material, which is a perforated polyethylene film. The film base sheet thickness is 34 ssm. The film is water permeable by virtue of perforations. The perforations are so-called "star punctures" formed on a 9 mm x 9 mm square grid pattern as described further below.

The sachet 1 contains partially cooked and dried rice.

The sachet is sealed by means of transverse top 2 and bottom 3 heat seals. A longitudinal heat seal (not shown) extends up the back of the sachet 1 to complete the sealing of the sachet 1.

A first line of perforations 4 extends in a straight line up the front of the sachet between the top 2 and bottom 3 transverse heat seals and parallel to an edge 8 of the sachet 1. A second line of perforations (not shown) extends up the back of the sachet and is directly overlapped by the first line of perforations 4. The first and second lines of perforations overlap in the region of the top and bottom transverse heat seals 2, 3. The first and second lines of perforations 2, 3 are closely spaced rows of punctures that permit easy tearing of the thermoplastics film along the lines of perforations.

A second top transverse heat seal 6 is provided approximately 1 cm above the first top transverse heat seal 2. A cut 7 extends inwardly from the edge 8 of the sachet between the first and second top transverse heat seals as far as the longitudinal line of weakness 4. A fork slot 9 approximately 2.5 cm long is provided by a lateral cut between the first and second top transverse heat seals.

In use, the rice in the sachet is cooked by immersing the sachet in boiling salted water. The sachet is then removed from the boiling water by inserting a fork in the fork slot 9 and lifting. Excess water is allowed to drain from the sachet and the sachet is then opened by grasping the top 10 of the tear strip 5 and pulling downwardly and outwardly. Once the tear strip has been removed the cooked rice can be poured from the sachet.

The above-described sachet can be opened by hand while still hot, without the aid of a knife or scissors. It therefore represents a substantial advance over existing boil-in-bag rice sachets.

Referring to Figure 4, the boil-in-bag rice sachet is made using a modified vertical form/fill/seal process. A continuous web 11 of thermoplastic material passes through an accumulator 12 and then over resilient roller 13. A perforating roller 14 presses into the resilient roller 13 through the web 11 and thereby forms perforations in the continuous web 11 in order to make it water-permeable.

Specifically, the perforating roller is provided on its surface with projections in the shape of triangular pyramids that pierce the continuous web 11 forming so-called "starpunctures" in a 9 mm x 9 mm square grid over substantially the whole of the web. The star punctures provide water permeability, but are spaced too far apart to provide easy tearing of the web material.

Two perforation cutters 15, 16 in the form of rotating discs having serrated edges also press into the resilient roller 13 through the web 11 and thereby cut two lines of closely spaced, tearable perforations 17, 18 extending longitudinally along the web 11. The web 11 is then wrapped around a filling tube 19 and undergoes conventional vertical filling and sealing to produce the boil-in-bag rice sachet.

Accordingly, it can be seen that the improved boilin-bag sachets according to the present invention are easy to make, requiring only a slight modification of existing manufacturing processes.

The above embodiment of the present invention has been described by way of example only. Many other embodiments falling within the scope of the accompanying claims will be apparent to the skilled reader.

Claims

1. A boil-in-bag sachet (1) comprising top (2) and bottom (3) transverse seals and being further provided with two longitudinal lines of weakness (4) on opposite sides of the sachet (1) defining a tear strip (5) in the sachet (1).

2. A boil-in-bag sachet (1) according to claim 1, wherein the lines of weakness (4) extend from the top transverse seal (2) to the bottom transverse seal (3).

3. A boil-in-bag sachet (1) according to claim 1 or 2 wherein the lines of weakness (4) overlap in the region of the top transverse seal (2) and/or in the region of the bottom transverse seal (3).

4. A boil-in-bag sachet (1) according to claim 1, 2 or 3 wherein the lines of weakness (4) are substantially straight and substantially parallel to each other.

5. A boil-in-bag sachet according to any preceding claim wherein the lines of weakness (4) are substantially straight, substantially parallel to each other, and substantially parallel to a longitudinal edge (8) of the sachet (1).

6. A boil-in-bag sachet (1) according to any preceding claim wherein the lines of weakness (4) are lines of perforations.

7. A boil-in-bag sachet according to any preceding claim further comprising a second transverse top seal (6) longitudinally spaced from the first transverse top seal (2), and wherein a transverse line of weakness (7) extends between said seals (2, 6) from an edge (8) of the sachet to at least one of the longitudinal lines of weakness (4).

8. A boil-in-bag sachet according to claim 7, which is further provided with a fork slot (9) between the first and second transverse top seals (2, 6).

9. A boil-in-bag sachet according to any preceding claim wherein the boil-in-bag sachet is water-permeable.

10. A boil-in-bag sachet (1) according to claim 9 wherein the boil-in-bag sachet (1) is perforated.

11. A boil-in-bag sachet (1) according to any preceding claim which is formed from a single web of film material.

12. A boil-in-bag sachet (1) according to any preceding claim wherein the sachet is formed from a thermoplastics material and the top and bottom transverse seals (2, 3) are heat seals.

13. A boil-in-bag sachet (1) according to any preceding claim containing a rehydratable food product.

14. A boil-in-bag sachet substantially as hereinbefore described with reference to the accompanying drawings.

15 A method of making a boil-in-bag sachet according to any preceding claim comprising the steps of: providing a web of plastics material having a tearable line of perforations formed therein, followed by forming the web into the boil-in-bag sachet.

16. A method according to claim 15 wherein the web is formed into the boil-in-bag sachet by a form/fill/seal process.

17 A method according to claim 15 of 16 wherein the tearable line of perforations extends longitudinally along the web of plastics material.

18. A method according to claim 15, 16 or 17 wherein the tearable line of perforations is produced with a rotating perforation cutter in the form of a disc or cylinder having perforation cutting teeth about its circumference.