PACKING CASE WITH TEAR STRIP

Abstract

A packing case blank including an opening device comprising a paper tear strip attached to the blank by a layer of adhesive.

Claims

1. A packing case blank including an opening device comprising a biodegradable paper tear strip attached to the blank by a layer of adhesive.

2. The blank of claim 1, wherein the biodegradable paper tear strip is attached to the blank along the majority of a length of the biodegradable paper tear strip.

3. The blank of claim 1, wherein fibres of the biodegradable paper tear strip are biased along a pull direction of the biodegradable paper tear strip.

4. The blank of claim 1, wherein the biodegradable paper tear strip is elongate along the pull direction of the biodegradable paper tear strip.

5. The blank of claim 1, wherein the adhesive is a water-based adhesive or PVA.

6. The blank of claim 1, wherein the adhesive is a gum-based adhesive.

7. The blank of claim 1, wherein a density of the biodegradable paper strip is between 125 GSM and 200 GSM.

8. The blank of claim 1, wherein a width of the biodegradable paper strip is between 4 mm and 10 mm, preferably between 5 mm and 7 mm, and most preferably 6 mm.

9. The blank of claim 1, further comprising one or more perforations arranged at an end of the biodegradable paper tear strip on opposing sides of the biodegradable paper tear strip, thereby to form a pull-tab.

10. The blank of claim 1, wherein the blank is a cartonboard blank or a corrugated fibreboard blank.

11. The blank of claim 1, wherein the biodegradable paper tear strip is made of kraft paper.

12. A method of manufacturing a packing case blank, comprising: applying a layer of adhesive to the blank; and, applying a paper tear strip to the layer of adhesive, thereby to attach the paper tear strip to the blank.

13. The method of claim 12, wherein applying the layer of adhesive comprises spraying the adhesive.

14. The method of claim 12, wherein applying the adhesive comprises applying the adhesive with a wheel or roller.

15. The method of claim 12, wherein the paper tear strip is applied with fibres of the paper tear strip biased along a pull direction of the tear strip.

16. The method of claim 12, wherein the paper tear strip is elongate along the pull direction of the tear strip.

17. The method of claim 12, wherein a density of the paper strip is between 125 GSM and 200 GSM.

18. The method of claim 12, wherein a width of the paper strip is between 4 mm and 10 mm, preferably between 5 mm and 7 mm, and most preferably 6 mm.

19. A spool of biodegradable paper tear strip for forming an opening device for cartonboard or corrugated fibreboard packaging material, the biodegradable paper tear strip comprising a continuous length of paper having a density of between 125 GSM and 200 GSM and a width of between 4 mm and 10 mm.

20. The spool of claim 19, wherein the width of the paper is between 5 mm and 7 mm, preferably 6 mm.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0082] Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0083] FIG. 1 shows a packing case including an opening device comprising a paper tear strip;

[0084] FIG. 2 shows the packing case of FIG. 1 in an open configuration;

[0085] FIG. 3 shows a side view of the opening device of the packing case of FIG. 1;

[0086] FIG. 4 shows the packing case of FIG. 1 in a closed configuration;

[0087] FIG. 5 shows the paper tear strip of the packing case of FIG. 1 being used to open the packing case;

[0088] FIG. 6 shows the packing case of FIG. 1 once the paper tear strip has been used to open the device;

[0089] FIG. 7 shows a reel of paper tear strip;

[0090] FIG. 8 shows a paper tear strip being applied to a packing case; and,

[0091] FIG. 9 illustrates a method for applying a paper tear strip to a packing case.

DETAILED DESCRIPTION

[0092] An embodiment of a packing case 100 is shown in FIG. 1, comprising a flap 101 in a closed configuration. The packing case can be made of any suitable material, but in preferred embodiments a material of the packing case is cartonboard or corrugated fibreboard.

[0093] FIG. 2 shows the packing case 100 with the flap 101 in an open configuration. The flap includes an opening device which comprises an elongate paper tear strip 102 adhered to an inner surface of the flap, with a pair of pull tabs 103 arranged at opposing ends of the paper tear strip 102. The pull tabs 103 are preferably each formed by a pair of perforations 104 in the flap arranged on opposing sides of the paper tear strip 102.

[0094] As shown in FIG. 3, the paper tear strip 102 is affixed to the packing case 100 by a layer of adhesive 105. As will be described later, the adhesive 105 is preferably applied directly to the packing case 105 during manufacture, and is preferably a water-based adhesive such as PVA or a gum-based adhesive, the latter of which may require water activation.

[0095] In the illustrated embodiment, the paper tear strip 102 extends slightly beyond the adhesive 105, although alternative embodiments are envisaged in which the entire surface of the paper tear strip 102 is coupled to the adhesive.

[0096] In use, once the packing case 100 has been packed, it is closed by folding the flap 101 and attaching it to a panel 107 of the packing case 100, preferably by means of an adhesive such as a pre-applied adhesive strip or sealing tape 106. The attachment between the flap 101 and the panel 107 is preferably strong enough such that the flap cannot be separated from the panel 107 once attached without damaging the packing case. The closed configuration of the packing case 100 is shown in FIG. 4.

[0097] To open the packing case, the user grips and pulls one of the pull tabs 103 in a direction generally perpendicular to the outer surface of the flap 101, as shown in FIG. 5. As the paper tear strip 102 is affixed to the pull tabs 103, pulling the pull tab 103 pulls the paper tear strip 102, thereby causing the paper tear strip 102 to tear through the packing case. In general, the substrate of packing case 100 to which the paper tear strip 102 is adhered will become dissociated from the rest of the packing case 100 during this process.

[0098] Once the paper tear strip 102 has been removed, a first portion 101a of the flap 101 remains adhered to the panel 107 of the packing case 100, as illustrated in FIG. 6, and a second portion 101b of the flap 101 can be folded back, thereby to open the packing case 100.

[0099] When the paper tear strip 102 is pulled, it is placed under tension. The paper tear strip 102 should therefore have a shear tensile strength that is sufficient for it to tear through the underlying substrate of the packing case 100.

[0100] To increase the tensile strength of the paper tear strip 102, the fibres of the paper tear strip 102 are preferably biased along the pull direction of the paper tear strip 102. Increasing the tensile strength of the paper tear strip 102 in this way reduces the risk that the paper tear strip 102 tears or otherwise breaks during opening for a given width and density of paper.

[0101] FIG. 7 shows a reel 200 of paper tear strip 102 for use in the manufacture of the packing case 100. The paper tear strip 102 can be made of any suitably strong paper, but is preferably made of kraft paper having a density of between 125 GSM and 200 GSM and a width of between 4 mm and 10 mm. The exact width and paper density can be chosen depending on the material of the packing case 101; for example a thicker or strong material may require a paper tear strip 102 with a higher density or larger width in order to ensure it is strong enough to tear through the packing case 100.

[0102] FIG. 8 illustrates a paper tear strip 102 being applied to a packing case 100 or packing case blank, for example on a high speed production line. The arrow depicts the direction of movement of the packing case 100.

[0103] An adhesive applicator 300 is used to apply the adhesive 105 to a substrate of the packing case 100 or packing case blank. In the illustrated embodiment, the adhesive applicator is a spray nozzle that sprays an adhesive onto a pre-determined substrate of the packing case 100. Alternative adhesive applicators 300 are also envisaged, such as rollers.

[0104] A tear strip applicator 400, in this case a roller, is then used to apply the paper tear strip 102 to the adhesive 105. The paper tear strip 102 will generally be drawn from a reel 200 or bobbin and cut to the required length before or during application, although it may also be possible to cut the paper tear strip 102 after application, for example by applying a continuous length of paper tear strip 102 to multiple packing cases and subsequently cutting the paper tear strip 102.

[0105] A method 500 for applying a paper tear strip 102 to a packing case 100 or packing case blank is shown in FIG. 9.

[0106] At step 501, the adhesive 105 is applied to a substrate of the packing case 100 or packing case blank. This can be applied using an adhesive applicator 300 such as a spray nozzle or a roller. As described above, the adhesive 105 could be a water-based adhesive such as PVA, or it may alternatively be any other suitable adhesive, such as a gum based adhesive.

[0107] Applying an adhesive 105 separately to a tear strip goes against conventional methods, which instead use a tear strip tape with a pre-applied adhesive.

[0108] At step 502, the paper tear strip 102 is applied to the adhesive 105. This may be applied using a tear strip applicator 400 such as a roller, and the paper tear strip 102 may be drawn from a reel 200 or bobbin and cut to the required length as necessary.

[0109] Although the above description has been given in the context of a paper tear strip 102 affixed adjacent to a pre-applied adhesive strip or sealing tape 106 on a closable flap 101, the paper tear strip 102 could equally be applied to other panels of the packing case 100, such as those that are glued during manufacture rather than when the packing case 100 is packed.

[0110] Equally, although the opening device has been described in relation to an envelope-style packing case, the paper tear strip 102 can be applied to any suitable packing case, including wraparound packing cases. The paper tear strip 102 can be used as a replacement for any conventional tear strip.