GB1575482A - Lined cartons - Google Patents

Description

(54) IMPROVEMENTS RELATING TO LINED CARTONS (71) We BOWATER PACKAGING LIMITED, a British Company, of Bowater House, Knightsbridge, London, SW1X, 7LR, do hereby declare the invention, for which we Ipray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state menu : This invention relates to improved siftproof or lined cartons and to the blanks therefor.

Such cartons are of course well known and are known in the trade as "liner" cartons. They are used for packaging pulverulent materials such as chemicals, sugar, flour, cereals and pelletised materials.

In particular such liner cartons are used for packaging products which smell offensive or which must be kept substantially free of moisture. The cartons can have many different ty.pes of end closure ranging from the traditional inner and outer pairs of closure flaps with which the liner is automatically folded inwards, to the more complicated types of closure such as are illustrated in U.K. Patent Specification Nos.

651711, 733144 and 808223. The present invention is applicable to all these types of carton.

The present invention seeks to provide liner cartons of the above-disclosed contructions which are cheaper to manufacture than known liner cartons, firstly because of a saving in materials and secondly because they do not require special manufacturing equipment.

According to the present invention, we provide a liner carton having first and second ends and one or more side wall panels extending between the ends wherein two liners are provided, one for each end of the carton, there being an unlined portion of the carton between its two ends, each liner being secured to the or each side wall panel by a continuous line of adhesive extending respectively around the ends of the side wall panels of the carton, each liner being secured additionally to selected areas of adjacent end closure flaps of the carton, so that all the end flaps are connected to one or other of the liners, each liner extending to or beyond the free outer edges of the closure flaps.

Preferably, the unlined portion of the carton is treated to make it moisture resistant or impervious to moisture.

According to one embodiment of the invention wherein the carton is a rectangular skillet with a first pair of opposed side walls and a second pair of opposed side walls extending at right angles to the first pair, each liner is secured to the end closure flaps foldably connected to the first pair of side wall panels and to triangular portions of the other pair of end closure flaps foldably connected to the other side walls, said triangular portions being defined by the fold line connecting the flaps to their respective side walls and lines drawn between the ends of said fold lines and the centre of the free edge parallel to said fold line.

Preferably, the continuous lines of adhesive connecting the liners to the four side walls also extend into a glue flap and are spaced from the top and bottom respectively of the side walls.

In a modified construction of skillet wherein one of the end closure flaps at each end of the carton is provided with a locking tab which tucks into a slot extending along part of the fold line joining the opposite end closure flap to its respective side wall, the continuous lines of adhesive can extend up to the fold lines connecting the end closure flaps with the side walls except in the vicinity of said slots where there must be a portion of the liner unconnected to its side wall over an area sufficient to accommodate the locking tab.

Also according to the present invention, we provide a carton blank for erection into a carton as described above, the blank comprising one or a plurality of interconnected side wall panels, a glue flap foldably connected to the or one of the -side wall panels and an end closure flap foldably connected to each end of the or each side wall panel and two liners each one adhesively secured to a respective end of the or each side wall panel by means of a continuous line of adhesive extending through the full width of the or each side wall panel and into the glue panel, there being an unlined portion of the carton blank between its two ends, each liner being secured additionally to selected areas of adjacent end closure flaps of the carton blank, so that all the flaps are secured to one or other of the liners, each liner ex- tending to or beyond the free outer edges of the closure flaps.

The invention, is now described by way of example with reference to the accompanying drawings, in which : - FIGURE 1 is a plan view of the inside of a blank for a first embodiment of carton showing a liner strip for one end of the carton only in place; FIGURE 2 is a perspective view looking down into the partly open end of a carton erected from the blank of Figure 1; FIGURE 3 is a view similar to Figure 1 showing a blank for a second embodiment of carton,. and FIGURE 4 is a perspective view showing a carton erected from the blank of Figure 3, one end of the carton being only partially closed.

The blank shown in Figure 1 is for a standard rectangular liner carton or skillet as shown in Figure 2 having a first pair of side wall panels 1 and 3 and a second pair of opposed side wall panels 5 and 7, the side wall panels being foldably connected in traditional manner by spaced parallel fold lines 9, 11 and 13. A glue flap 15 is foldably connected to the side wall panel 3 about a further fold line 17 parallel to the fold lines 9, 11 and 13.

At each end of the carton a pair of inner end closure flaps 19, 21 is foldably connected to the side wall panels 7 and 5 about fold lines 23 and 25 respectively and a pair of outer end closure flaps 27 and 29 is foldably connected to the side wall panels 1 and 3 about fold lines 31 and 33 respectively. The fold lines 23, 25, 31- and 33 are normal to the other fold lines. The side edges of each end closure flap are recessed as at 35. The blank itself is formed of a semi-stiff fibreboard and a liner 41 is adhesivelv secured to each end of the blank (the parts forming the ends of the carton) by means of continuous lines of adhesive 43 each extending from one side of the blank to the other, i.e. from the free edge of the side wall panel 5 to the free edge of the glue flap 15. Each line of adhesive 43 is preferably spaced a short distance from the adjacent fold lines 23, 25, 31, 33.The liners 41 correspond in length to the length of the blank and extend from slightly inwardly of the internal edges of the lines of adhesive 43 to the free edges of the end closure flaps 19, 21, 27, 29 or even beyond these free edges, and each liner is adhesively secured, at least to central portions if not to the whole inner surface area of the inner end closure flaps 19 and 21 and to triangular portions 45 of the external closure flaps 27 and 29, the triangular portions being defined respectively by the fold lines 31 and 33 and by straight lines extending from the ends of the fold lines 31 and 33 across the respective flaps 27 and 29 to a point at the centre of the free edge of the respective flaps. It will thus be appreciated that a central portion 47 of the blank remains unlined, i.e. the liners only extending over the two end portions of the carton.

To form the blank of Figure 1 into a carton as shown in Figure 2, adhesive is applied to the outer face of the glue flap 15 and over the portions of the liners located respectively between the ends of the glue flap 15 and end closure flaps 29, or to the inner edge regions of the panel 5 and flaps 21, whereupon the carton can be folded up into a traditional sleeve in known manner. One of the ends of the carton is then formed largely in known manner by first folding in the inner end closure flaps 19 and 21 together with the portions of liner secured thereto. This operation can be achieved easily by pulling out slightly on a central edge region of one of the outer end closure flaps. When the two inner end closure flaps have been folded inwardly to overlie the end of the sleeve, the liner portions overlying the outer end closure flaps, because they are adhesively secured only to the triangular portions 45, will automatically be folded in the manner illustrated in Figure 2. Closure is completed by folding in the two outer end closure flaps consecutively so that one overlies the other and of course the carton will be filled prior to formation of the second end closure.

A liner carton will result in which leakage of the contents from the carton or contact of the contents with atmosphere is substantially prevented due to the two liners completely sealing off what would otherwise be small air passageways in the two ends of the carton.

The embodiment illustrated in Figures 3 and 4 is similar to that of Figures 1 and 2 and like parts bear- the same reference numerals. This embodiment, however, differs from the previous embodiment in that locking flaps 51 of traditional construction are foldably connected to a central part of the free edge of each of the outer end closure flaps 27 along the fold line 53, these locking flaps in the erected carton tucking into' slits 55 formed along central portions of the fold lines 33, connecting the other outer end closure flaps 29 to their respective side wall panels. Furthermore, the width of the two liners 41 is slightly different as are the widths of the continuous lines of adhesive 43.Furthermore, an unglued area 57 is provided in each end region of the side wall panel 3 so that the locking flaps 51 can be accommodated between the liner and side wall panel in the erected carton.

The carton shown in Figure 4 is erected in the same manner as that shown in Figure 2 although instead of glueing the two outer glue flaps 27 and 29 together, the end closures are locked in position as a resultKof the locking flaps 51 being engaged in their respective slots 55.

It will 'be appreciated that many different designs of carton can be used embodying the principles of the present invention. In particular, cartons other than rectangular cartons are envisaged and many different designs' of end closure would be possible.

For various products the above-described cartons can be used without any particular surface treatment to the unlined central region 47 of the blank. However, if the product to be packed gives off an unpleasant odour or must be kept in moist condition or must be isolated from the atmosphere, then a suitable surface treatment is given at least to the central portion 47 of the blank. This surface treatment could be any one of the known treatments, e.g it could be waxed or sprayed with a synthetic resinous layer.

Obviously, by omitting a liner over the central portion 47 of the blank there is a saving in liner material which can be quite considerable with large cartons, such as, for example, cartons for breakfast cereals.

A further advantage of the present invention is that we can utilise our standard window carton manufacturing machinery for manufacturing the blanks described herein. The production cycle would be as follows: 1. The pre-cut/pre-creased blanks are located in a feed hopper of the window carton machine; 2. The blanks are fed through the machine at predetermined intervals with their glue flaps 15 trailing; 3. The two lines of adhesive 43 are applied and at the same time the required adhesive is applied with the aid of a stencil to the selected areas of the end closure flaps; 4. The adhesive coated blank then passes under two pre-positioned reels of treated liner material of the required width; 5. When the presence of a blank 'is indicated below the reels, lengths 41 of the liner material are cut and positioned at either end of the blank; 6.The lined blank then passes under pressure rollers to adhere the liner strips to the blank; 7. The lined blank emerges from the pressure rollers ready for glueing, e.g.

along the glue flap and exposed regions of the liner.

The resultant pre-folded glued carton blanks can now be stacked and stored and supplied to the users as required. These blanks can be erected, filled and closed manually, automatically or semiautomatically, or they can be manually, automatically or semi-automatically erected and filled and automatically sealed or closed. In other words, any combination of manual, automatic or semi-automatic erecting, filling and closing systems can be used using a customer's existing machinery or readily available machinery which the customer can buy or lease.

WHAT WE WE CLAIM IS:- 1. A liner carton having first and second.

ends and one or more side wall panels extending between the ends wherein two liners are provided, one for each end of the carton, there being an unlined portion of the carton between its two ends, each liner being secured to the or each side wall panel by a continuous line of adhesive extending respectively around the ends of the side wall panels of the carton, each liner being secured additionally to selected areas of adjacent end closure flaps of the carton, so that all the end flaps are secured to one or other of the liners, each liner extending to or beyond the free outer edges of the closure flaps.

2. A liner carton as claimed in claim 1 wherein the unlined portion of the; carton is treated to make it moisture resistant or impervious to moisture.

3. A liner carton as claimed in claim 1 or claim 2 wherein the continuous lines of adhesive connecting the liners to the side wall panels also extend into a glue flap.

4. A liner carton as claimed in claim 1, 2 or 3 wherein the carton is a rectangular skillet with a first pair of opposed side walls and a second pair of opposed side walls extending at right angles to the first pair, each liner being secured to the end closure flaps foldably connected to the first pair of side wall panels and to tri

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. and 4 is similar to that of Figures 1 and 2 and like parts bear- the same reference numerals. This embodiment, however, differs from the previous embodiment in that locking flaps 51 of traditional construction are foldably connected to a central part of the free edge of each of the outer end closure flaps 27 along the fold line 53, these locking flaps in the erected carton tucking into' slits 55 formed along central portions of the fold lines 33, connecting the other outer end closure flaps 29 to their respective side wall panels. Furthermore, the width of the two liners 41 is slightly different as are the widths of the continuous lines of adhesive 43.Furthermore, an unglued area 57 is provided in each end region of the side wall panel 3 so that the locking flaps 51 can be accommodated between the liner and side wall panel in the erected carton. The carton shown in Figure 4 is erected in the same manner as that shown in Figure 2 although instead of glueing the two outer glue flaps 27 and 29 together, the end closures are locked in position as a resultKof the locking flaps 51 being engaged in their respective slots 55. It will 'be appreciated that many different designs of carton can be used embodying the principles of the present invention. In particular, cartons other than rectangular cartons are envisaged and many different designs' of end closure would be possible. For various products the above-described cartons can be used without any particular surface treatment to the unlined central region 47 of the blank. However, if the product to be packed gives off an unpleasant odour or must be kept in moist condition or must be isolated from the atmosphere, then a suitable surface treatment is given at least to the central portion 47 of the blank. This surface treatment could be any one of the known treatments, e.g it could be waxed or sprayed with a synthetic resinous layer. Obviously, by omitting a liner over the central portion 47 of the blank there is a saving in liner material which can be quite considerable with large cartons, such as, for example, cartons for breakfast cereals. A further advantage of the present invention is that we can utilise our standard window carton manufacturing machinery for manufacturing the blanks described herein. The production cycle would be as follows: 1. The pre-cut/pre-creased blanks are located in a feed hopper of the window carton machine; 2. The blanks are fed through the machine at predetermined intervals with their glue flaps 15 trailing; 3. The two lines of adhesive 43 are applied and at the same time the required adhesive is applied with the aid of a stencil to the selected areas of the end closure flaps; 4. The adhesive coated blank then passes under two pre-positioned reels of treated liner material of the required width; 5. When the presence of a blank 'is indicated below the reels, lengths 41 of the liner material are cut and positioned at either end of the blank; 6.The lined blank then passes under pressure rollers to adhere the liner strips to the blank; 7. The lined blank emerges from the pressure rollers ready for glueing, e.g. along the glue flap and exposed regions of the liner. The resultant pre-folded glued carton blanks can now be stacked and stored and supplied to the users as required. These blanks can be erected, filled and closed manually, automatically or semiautomatically, or they can be manually, automatically or semi-automatically erected and filled and automatically sealed or closed. In other words, any combination of manual, automatic or semi-automatic erecting, filling and closing systems can be used using a customer's existing machinery or readily available machinery which the customer can buy or lease. WHAT WE WE CLAIM IS:-

1. A liner carton having first and second.

ends and one or more side wall panels extending between the ends wherein two liners are provided, one for each end of the carton, there being an unlined portion of the carton between its two ends, each liner being secured to the or each side wall panel by a continuous line of adhesive extending respectively around the ends of the side wall panels of the carton, each liner being secured additionally to selected areas of adjacent end closure flaps of the carton, so that all the end flaps are secured to one or other of the liners, each liner extending to or beyond the free outer edges of the closure flaps.

2. A liner carton as claimed in claim 1 wherein the unlined portion of the; carton is treated to make it moisture resistant or impervious to moisture.

3. A liner carton as claimed in claim 1 or claim 2 wherein the continuous lines of adhesive connecting the liners to the side wall panels also extend into a glue flap.

4. A liner carton as claimed in claim 1, 2 or 3 wherein the carton is a rectangular skillet with a first pair of opposed side walls and a second pair of opposed side walls extending at right angles to the first pair, each liner being secured to the end closure flaps foldably connected to the first pair of side wall panels and to tri

angular portions of the other pair of end closure flaps foldably connected to the other side walls, said triangular portions being defined by the fold line connecting the flaps to their respective side walls and lines drawn between the ends of said fold lines and the centre of the free edge parallel to said fold line.

5. A liner carton as claimed in claim 4 wherein one of the end closure flaps at each end of the carton is provided with a locking tab which tucks into a slot extending along part of the fold line joining the opposite end closure flap to its respective side wall.

6. A liner carton as claimed in claim 5 wherein the continuous lines of adhesive extend up to the fold lines connecting the end closure flaps with the side walls except in the vicinity of said slots where there is a portion of the liner unconnected to its side wall over an area at least sufficient to accommodate the locking tab.

7. A liner carton as claimed in any one of the preceding claims 1-5 wherein the continuous lines of adhesive are inwardly spaced from the outer edges of the side wall panels.

8. A carton substantially as hereinbefore described with reference to Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.

9. A carton lilank for erection into a carton as claimed in any one of the preceling claims, the blank comprising one or a plurality of interconnected side wall panels, a glue flap foldably connected to the or one of the side wall panels and an end closure flap fold ably connected to each end of the or each side wall panel and two liners each one adhesively secured to a respective end of the or each side wall panel by means of a continuous line of adhesive extending throughout the full width of the or each side wall panel, and into the glue panel, there being an unlined portion of the carton blank between its two ends each liner being secured additionally to selected areas of adjacent end closure flaps of the carton blank, so that all the end flaps are secured to one or other of the liners, each liner extending to or beyond the free outer edges of the closure flaps.

10. A carton blank substantially as hereinbefore described with reference to Figure 1 or Figure 3 of the accompanying drawings.