WO2013010815A1

WO2013010815A1 - A carton

Info

Publication number: WO2013010815A1
Application number: PCT/EP2012/063247
Authority: WO
Inventors: Prabuddha DASGUPTA; Rashi DHIMAN; Sandeep Mukherjee; Ambrish BHARGAVA
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Unilever Limited
Priority date: 2011-07-19
Filing date: 2012-07-06
Publication date: 2013-01-24

Abstract

The present invention relates to a carton for packing leaf tea products. Reduction of the use of materials is highly desired for environmental reasons. Reducing the amount of packaging material is not only more sustainable, but also cost effective. It is an object of the present invention to provide a carton for packing leaf tea products with significantly less material consumption than either bag-in-a-box type configuration or cartons for packing liquid materials. The present inventors have surprisingly found that a carton which is formed from a single piece of composite comprising polyethylene terephthalate as the outer-layer, polyethylene as the inner-layer and paper board as a middle layer is capable of storing non-liquid food products like tea leaf without compromising the product quality and at the same time consumes less material than existing cartons.

Description

A CARTON

Technical Field

The present invention relates to a carton for packing leaf tea products.

Background of the invention

Various types of cartons are known for packing food materials of different kinds e.g. milk, oil, tea leaves etc. Currently available cartons which are used for packing of non-liquid products like tea leaves, where providing a moisture barrier and retaining product quality is of prime concern, generally use a bag-in-a-box type configuration. In this configuration the bag inside the carton provides a barrier which prevents oxygen and moisture reaching the material inside in order to preserve the product during storage and on shelf. These barrier materials usually are made up using various polymers and paper.

Similarly, available cartons which are used for packing liquid materials use a number of layers including aluminum foil which provides a barrier to oxygen and moisture and thereby prevents microbial growth in the liquid. These cartons also use a polyethylene layer on the outer surface to make it heat-sealable as required by the currently available process.

The main drawback of currently available cartons is that they require a large amount of material. In case of bag-in-a-box type configuration, the consumption of materials is high because both the bag and the box have to be made using suitable material. In other types of cartons which are used for liquid products the material consumption is high because those require additional layers to provide a hermetically sealed pack. Such layers include aluminum foil. Also, in case of liquid product packing especially for milk etc. the packaging is done under aseptic condition which makes the process even more costly. Reduction of the use of materials is highly desired for environmental reasons. Reducing the amount of packaging material is not only more sustainable, but also cost effective. Several types of cartons have been disclosed in the art.

US 3,279,678 (Tetra Pak AB, 1966) discloses a package preferably used for liquid filling material, formed by sealing a filled tube at intervals, shaping the package, and cutting the tube at the seals. The package is provided with a reinforcing panel on one of its sides. The package may itself be of coated thermoplastic material, e.g. polyethylene, wax or lacquer and sealed by pressure; or it may be sealed with glue at the joints.

US 5,851 ,608 (DAINIPPON PRINTING CO LTD, 1998) discloses a paper container for storing liquid such as juice and liquid yogurt. The container includes a base material including: a paper layer, a polyolefin type resin layer disposed on one side of the paper layer for providing an outer surface, and a saturated polyester resin layer disposed on the other side of the paper layer by the medium of a polyolefin type resin layer for providing an inner surface. The paper container is formed from the base material so that the polyolefin type resin layer for providing the outer surface provides an outer peripheral surface of the container wherein the paper and the saturated polyester resin have some particular properties. US 5,851 ,608 deals with the problem of odor imparted by polyolefin based on the inner peripheral surface layer.

EP 0 936 150 (TETRA LAVAL HOLDINGS AND FINANCE, 1999) discloses an aseptic package for pourable food products e.g. long life (UHT) milk. EP0936150 provides a pre-creased packaging sheet material having a laminated structure including at least one fibre based layer and at least one aseptic barrier layer for manufacturing aseptic packages. EP0936150 addresses the problem of aseptic barrier integrity in the package and intends to reduce the serious health risk imparted by packages which are not properly aseptic or which lose the aseptic barrier for various reasons as mentioned in this document.

We have also found that polyethylene layer which is generally used as the external layer because of its heat sealable property, does not provide a glossy attractive look of the carton.

However there remains a need for a carton for packing non-liquid food materials such as tea leaf, which provides a moisture barrier and retains product quality whilst requiring significantly less material than conventional bag-in-a-box type cartons or cartons for packing liquid materials and also provides a glossy attractive finish externally.

Objects of the invention

In view of the foregoing, it is an object of the present invention to provide a carton for packing leaf tea product which provides a moisture barrier and retains product quality.

It is another object of the present invention to provide a carton for packing leaf tea product which requires significantly less material than conventional bag-in-a-box type cartons or cartons for packing liquid materials.

It is a further object of the invention to provide a carton for packing leaf tea product without compromising the product storage performance.

It is yet another object of the present invention to provide a carton with a glossy attractive external finish for packing leaf tea product.

It is yet a further object of the present invention to reduce the material usage thereby decreasing the environmental footprint. The present inventors have surprisingly found that a carton which is formed from a single piece of composite comprising polyethylene terephthalate as the outer- layer, polyethylene as the inner-layer and paper board as a middle layer is capable of storing leaf tea products without compromising the product quality and at the same time consumes less material than existing cartons and also provides a glossy external finish.

Summary of the invention

In a first aspect the present invention provides a shaped packaging carton containing a leaf tea product, the carton being formed form a single pre-creased flat blank, comprising an edge section on the periphery of the blank and two surfaces, external and internal; the blank comprising crease-lines on the surfaces, the blank characterized by comprising polyethylene terephthalate as the outer- layer, polyethylene as the inner-layer and paper board material as a middle layer, the blank:

a. being folded over the crease lines thereby forming a volume inside the folded inner surface of the blank having the polyethylene layer and

b. being sealed over the edge section, wherein when folded the entire length of the edge section meets an opposing part of the edge section;

further characterized in that the inner-layer to inner layer sealing is carried out by application of heat in the form of a fin-seal and the inner layer to outer layer or outer layer to outer layer seals are formed by means of a hot-melt glue.

According to a second aspect the present invention there is provided a process for making a carton containing a leaf tea product comprising the steps of:

a) providing a single pre-creased flat blank which comprises an edge section on the periphery of the blank and two surfaces, external and internal; the blank comprising crease-lines on the surfaces, the blank characterized by comprising polyethylene terephthalate as the outer- layer, polyethylene as the inner-layer and paper board material as a middle layer, b) folding the blank over the crease lines so that the entire length of the edge section meets an opposing part of the edge section thereby forming a volume inside the folded inner surface of the blank,

c) heat-sealing the two edges that are not opposite to centre crease fold in the form of a fin-seal thus forming a open-mouthed bag,

d) erecting the carton in such a way that the open mouth is at the top and crease fold is at the bottom; the bottom part having two ears at the fin- sealed side edges,

e) pouring a leaf tea product into the open mouth of the carton,

f) heat sealing the mouth, thus forming two further ears at the fin sealed edges of the mouth end, and

g) folding all the ears either to the fin-sealed side or the other side of the carton and attaching them by means of a hot melt glue. These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. It is noted that the figures given in the description below are intended to clarify the invention and are not intended to limit the invention to those figures per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. Brief description of the drawings

Figure 1 is a preferred embodiment of the pre-creased flat blank of the invention. Figure 2 is a perspective view of the flat blank of Figure 1 after folding it from the centre crease line. Figure 3 is a view of the folded blank of Figure 2 after sealing the two opposite edges in the form of a fin-seal.

Figure 4 is a perspective view of the carton with the ears and open mouth formed from the folded blank of Figure 3.

Figure 5 is a perspective view of formed carton of Figure 4 after sealing the open mouth.

Detailed description of the invention

Carton of the present invention:

The carton according to the present invention is made from a pre-cut sheet of a layered packaging material. Such a pre-cut sheet is typically referred to in the art as a blank, sheet, lay-flat carton etc.

The present invention provides a shaped packaging carton for leaf tea products formed form a single pre-creased flat blank, comprising an edge section on the periphery of the blank and two surfaces, external and internal; the blank comprising crease-lines on the surfaces, the blank characterized by comprising polyethylene terephthalate as the outer-layer, polyethylene as the inner-layer and paper board material as a middle layer, the blank:

a) being folded over the crease lines thereby forming a volume inside the folded inner surface of the blank having the polyethylene layer and

b) being sealed over the edge section, wherein when folded the entire length of the edge section meets an opposing part of the edge section; further characterized in that the inner-layer to inner layer sealing is carried out by application of heat in the form of a fin-seal and the inner layer to outer layer or outer layer to outer layer seals are formed by means of a hot-melt glue. The flat blank is preformed with crease lines. The flat blank has two surfaces; external and internal. The crease lines of the blank are formed on the surfaces of the blank. The crease lines are provided preferably both in the longitudinal and the transverse directions. The blank comprises polyethylene terephthalate (PET) as the outer-layer which is on the external surface, polyethylene (PE) as the inner- layer which is on the internal surface and paper board material as a middle layer. We have found that using PET for the external layer provides a carton with a ossy finish, which is preferred by consumers.

The PET layer has a thickness preferably of 8 to 12 microns more preferably 9 to 10 microns. The middle layer of paper board is provided with a preferable density of 190 to 230 gsm more preferably 200 to 210 gsm. The PE layer is has a preferable thickness of 15 to 20 microns more preferably 16 to 18 microns.

The carton formed by folding the blank has the PE layer inside and PET layer outside. There is no restriction on the size the shape of the flat blank. The most preferable shape of the blank is generally rectangular.

Similarly the carton of the present invention may have different shapes and sizes. The preferable shape of the carton is cuboid, polygonal, triangular etc. The most preferable shape of the carton is six faced rectangular carton. The size of the carton is dependent on how much product it is designed to contain. As the carton of the present invention is made from a single blank it preferably has lesser dimension when compared with bag-in-a-box type carton for holding same amount of product (since it does not also need to contain a bag).

In a preferred embodiment the shaped packaging carton of the invention is made by folding the blank along the centre crease line which divides the blank in two rectangular halves such that, when folded, all edges meet. The two edges that are not opposite to the centre crease fold are heat sealed in the form of a fin-seal forming a open-mouthed bag adapted for pouring the material from the mouth; characterized in that the carton when standing upright having the open mouth at the top and the crease fold at the bottom has two ears at the fin-sealed side edges of the carton wherein the ears are folded towards either the bottom or the fin- sealed side of the carton and attached by means of a hot-melt glue.

In the above mentioned preferred embodiment, folding the blank along the centre crease line divides the blank in two equal rectangular halves such that, when folded, all edges meets. The two edges that are not opposite to the centre crease fold are heat sealed in the form of a fin-seal. PE is provided as the inner layer of the carton to make it capable of being heat sealed. After sealing the edges an open mouthed bag is formed, which is adapted for filling through the mouth.

The preferred carton when standing upright having the open mouth at the top and the crease fold at the bottom has two ears at the fin-sealed side edges of the carton wherein the ears are attached to either the bottom or the fin-sealed side of the carton by means of a hot-melt glue.

Preferably, after filling the contents into the carton through the mouth, the mouth is heat sealed in the form of a fin-seal. The mouth end has two more ears at the fin- sealed side edges which are then attached to either the top or the fin-sealed side of the carton by means of hot melt glue.

One of the characteristic features of the carton of the present invention is that the inner-layer to inner layer sealing is carried out by application of heat in the form of a fin-seal and the inner layer to outer layer or outer layer to outer layer sealing is achieved by means of a hot-melt glue. This means that the PE layer to PE layer seal is carried out by applying heat in the form of a fin-seal and PET layer to PET layer or PET layer to PE layer sealing is carried out by application of a hot-melt glue. Any type of compatible hot-melt glue may be used for this purpose. The preferred hot-melt glue is comprised of hydrocarbon resins and polyolefin.

Optionally a screw-cap may be included on the carton. Screw-caps for cartons are commonly used in the art and typically comprise a plastic base glued over a punctured section of the carton, wherein the puncture is covered (in an air and water tight manner) with a removable or rupturable sheet of material. The base contains the screw thread on the outside. A cap, having an inner thread is screwed on top of the base.

Process for making the carton of the present invention:

The present invention also provides a process for making a carton containing a leaf tea product comprising the steps of:

a) providing a single pre-creased flat blank which comprises an edge section on the periphery of the blank and two surfaces, external and internal; the blank comprising crease-lines on the surfaces, the blank characterized by comprising polyethylene terephthalate as the outer- layer, polyethylene as the inner-layer and paper board material as a middle layer,

b) folding the blank over the crease lines so that the entire length of the edge section meets an opposing part of the edge section thereby forming a volume inside the folded inner surface of the blank,

e) pouring a leaf tea product into the open mouth of the carton,

g) folding all the ears either to the fin-sealed side or the other side of the carton and attaching them by means of a hot melt glue. ln a preferred embodiment the process of the invention, the folding of the single pre-creased flat blank divides the blank into two equal rectangular halves such that when folded all edges meet.

The open mouthed bag thus formed can be filled up by material for which the carton is developed.

After pouring the leaf tea product into the mouth, the mouth is sealed by heat in the form of a fin-seal. This forms another two ears at mouth end. The ears at the mouth end are then attached either to the top or to the fin-sealed side with hot melt glue.

The carton of the present invention is designed for packaging leaf tea products. Leaf tea products include leaf tea, dust tea and/or tea fannings.

Detailed description of the drawings

The invention will now be demonstrated with the help of non-limiting figures. Referring to Figure 1 , this represents an embodiment of the blank according to the invention. The flat blank (FB) has pre-formed crease lines (CL) both in longitudinal and in transverse direction, which is represented in the figures as dotted lines. The flat blank is defined by four edges viz. E1 , E2, E3 and E4 wherein E1 and E3 are opposite to each other. Similarly E2 and E4 are also opposite to each other. The inner surface (IS) of the flat blank is shown in Figure 1 . The inner layer of the blank i.e. polyethylene forms the inner surface. In the middle of the blank there is shown a centre crease line (CCL). The blank is folded from the centre crease line.

Now referring to figure 2, this shows the folded flat blank. The flat blank is folded from the centre crease line thereby forming a centre crease fold (CCF). When folded the opposite edges E2 and E4 meets each other. After folding E2 and E4 are now opposite to centre crease fold. The other two edges E1 and E3 of the flat blank become half of their original length and the two equal half-edges (E17 E1 " and E37E3") of the same edge meets each other. The outer surface (OS) of the flat blank is shown in Figure 2. The outer layer of the blank i.e. polyethylene terephthalate forms the outer surface.

Further referring to Figure 3 which represents the folded flat blank after being sealed the two half-edges by heat. The half-edges E1 ' and E1 " (not shown in the figure, only shown as E1 ) sealed in the form of a fin-seal (FS) by applying heat. The same seal is made with E3' and E3" (not shown in the figure, only shown as E3). An open mouth (OM) is formed after sealing the edges. The open mouth is adapted for pouring the material, which needs to be stored, into the carton.

Now referring to Figure 4 which is another perspective view of the semi formed carton wherein the open mouth is at the bottom. Two ears viz. ER1 and ER2 are formed by folding the blank. The fin-seal (FS) is shown at the side face of the carton. The ears may be attached to the fin-seal side or to the centre crease line (CCL) side by means of hot melt glue.

Figure 5 represents a perspective view of the formed carton wherein the two ears (one of them is shown in the figure as ER1 ) formed at the centre crease line (CCL) side are now attached with the fin-sealed side with hot melt glue. The open mouth is also sealed up in the form of a fin-seal after pouring the material. After the mouth is sealed up the other two ears are formed viz. ER3 and ER4 (not shown in the figure). These two ears may be attached to the fin-seal side or to the other side by means of hot melt glue. The fin-seal (FS) is shown at the side face of the carton.

Now the invention will be demonstrated with the help of examples. The following examples are for illustrations only and no way limit the scope of the invention.

Examples: Comparison of flat laminated blank in terms of their appearance and functionality, formed by different material:

Two rectangular flat single pre-creased blank of same dimension were made as follows:

a) a first blank was made using 10 gsm PE as outer-layer, 190 gsm paper board as middle layer and 12 gsm PE as inner-layer (generally used for making carton).

b) A second blank was made using 10 micron PET as outer-layer, 190 gsm paper board as middle layer and 12 gsm PE as inner layer (blank for making carton according to the present invention).

The two flat blanks were tested for their WVTR (water vapour transmission rate) and OTR (oxygen gas transmission rate). WVTR represents the moisture barrier for a particular composite and OTR represents the aroma barrier. The lower the values of these parameters, the better the blank is for making a carton for storing leaf tea products. WVTR was measured using Lyssy (model number: L-80-5000) by following the standard procedure ASTM E 398-03. OTR was measured using GBPI (model number: 1000 Oxygen Trap, supplier Chromatography Research Supplier, Inc.) by following the standard procedure ASTM-F1927. The appearances of these blanks were also checked from the outer side. The results are summarized below in Table 1 :

Table 1 :

From the above Table it is evident that use of a blank made of PET-board-PE is beneficial over PE-board-PE. The blank made with the PET-board-PE structure has much greater resistance to moisture and oxygen and also provides an external surface with glossy attractive finish. As leaf tea products are sensitive to moisture and oxygen it is better to use PET- board-PE structure rather than PE-board-PE.

Comparison of the moisture content of leaf tea products between currently used bag-in-a-box type carton and carton of the present invention

Six 100 g packs of Brooke bond® Red Label black tea using a currently available bag-in-a-box type carton) were placed in a hot and humid chamber (temperature of 37± 2 °C and relative humidity of 90 ± 2 %). At the same time Six 100 g packs of Brooke bond® Red Label black tea using the carton of the present invention was also placed inside the same hot and humid chamber. After the specified time as mentioned in Table 1 , one carton of each of bag-in-a-box type and carton of the present invention were taken out from the chamber. The moisture content of these samples was measured using an OHAUS MOISTURE BAL - MB45 instrument. The procedure is given below:

Procedure:

i. Open the lid of the instrument & place a clean, empty Aluminum dish

ii. Before placing the sample, select test method from Test Menu'

iii. Press Test Menu' and select the required method, namely 105°C for 10 min. iv. Now, tare the Aluminum dish using the Tare' button

v. Weigh out the 2 g of tea leaf & spread it evenly in the tared Aluminum dish vi. Close the lid of the instrument

vii. Press the 'Start' button on the panel

viii. The instrument is set to read the % loss of weight

ix. Note down the % moisture content reading from display panel once Test over' message is displayed.

The results of the experiment are summarized below in Table 2. In Table 1 Carton type - I refers to bag-in-a-box type carton and Carton type - II refers to carton of the present invention.

Table 2 Time Moisture content (wt %)

Carton type - 1 Carton type - II

15 days 7.3 7.2

30 days 7.4 7.3

45 days 7.3 7.5

60 days 7.4 7.6

90 days 7.6 7.5

120 days 7.8 7.9

From the above Table 2 it is evident that the tea products in Carton type - I and Carton type - II have the same moisture content after storage, i.e. the product quality remains the same for both types of carton.

Comparison of leaf tea product quality between currently used baq-in-a-box type carton and carton of the present invention

Tea tasting was also carried out by a panel of tea experts. The tea was tasted in terms of liquor and flavor quality after storing it for the time span as mentioned in Table 1 . It was found by the tea experts that the quality of the tea product stored in the carton of the present invention is comparable with currently available bag- in-a-box type carton. Comparison of amount of material required for making a carton of the present invention and currently used bag-in-a-box type carton

Two different sets of cartons were made for packing two different weights of tea leaf. For each set two cartons were made; one bag-in-a-box type carton and one carton of the present invention as per the following Table 2. The tea used for packing was Brooke bond® Red Label black tea. The cartons were six-faced rectangular shaped. The results are summarized below in Table 3. In the Table 2 Carton type - I refers to bag-in-a-box type carton and Carton type - II refers to carton of the present invention. Table 3

From the above table it is evident that for packing same amount of product the carton of the present invention consumes much less material than currently available bag-in-a-box type carton. The material savings is 38% for packing 245 g of tea and as high as 49% for packing 490 g of tea product.

Therefore by way of present invention it is possible to provide a carton for packing leaf tea products with significantly less material consumption than a bag-in-a-box type configuration. The carton of the invention also requires less material than conventional cartons which are used for liquid products which have additional layers to provide a hermetically sealed pack. The carton of the present invention is also attractive and glossy.

Claims

Claims:

1 . A shaped packaging carton containing a leaf tea product, the carton being formed form a single pre-creased flat blank, comprising an edge section on the periphery of the blank and two surfaces, external and internal; the blank comprising crease-lines on the surfaces, the blank characterized by comprising polyethylene terephthalate as the outer-layer, polyethylene as the inner-layer and paper board material as a middle layer, the blank:

a) being folded over the crease lines forming a volume inside the folded inner surface of the blank having the polyethylene layer and

b) sealed over the edge section, wherein when folded the entire length of the edge section meets an opposing part of the edge section;

further characterized in that the inner-layer to inner layer sealing is carried out by application of heat in the form of a fin-seal and inner layer to outer layer or outer layer to outer layer are sealed by means of a hot-melt glue.

2. A shaped packaging carton as claimed in claim 1 wherein the blank is folded along the centre crease line which divides the blank into two rectangular halves such that when folded all edges meet; and the two edges that are not opposite to the centre crease fold are heat sealed in the form of a fin-seal thereby forming a open-mouthed bag adapted for pouring the leaf tea product from the mouth; wherein the carton when standing upright has the open mouth at the top and the crease fold at the bottom and has two ears at the fin-sealed side edges of the carton wherein the ears are folded towards either the bottom or the fin-sealed side of the carton and attached by means of a hot-melt glue.

3. A carton as claimed in claim 2 wherein the mouth is heat sealed in the form of a fin-seal and the mouth end which has two further ears at the fin-sealed side edges which are folded towards either the top or the fin-sealed side of the carton and are attached by means of a hot melt glue. A carton as claimed in any one of the preceding claims 1 to 3 wherein the hot melt is comprised of hydrocarbon resins and polyolefin.

A process for making a carton containing a leaf tea product comprising the steps of:

e) pouring a leaf tea product into the open mouth of the carton,

g) folding all the ears either to the fin-sealed side or the other side of the carton and attaching them by means of a hot melt glue.

A process as claimed in claim 5 wherein the folding of the single pre-creased flat blank divides the blank in two equal rectangular halves such that when folded all edges meet.