EP3102492B1

EP3102492B1 - A method for producing stand-up pouches of stretchable paper

Info

Publication number: EP3102492B1
Application number: EP15702274.0A
Authority: EP
Inventors: Gary Robinson; Hein VAN DEN REEK; Åke REUTERHAGE
Original assignee: Billerudkorsnas AB
Current assignee: Billerudkorsnas AB
Priority date: 2014-02-06
Filing date: 2015-02-03
Publication date: 2020-04-15
Anticipated expiration: 2035-02-03
Also published as: WO2015117954A3; JP2017505266A; EP3102492A2; WO2015117954A2; CN105992734A; US20160340069A1

Description

TECHNICAL FIELD

The invention relates to paper stand-up pouches of a stretchable paper material and the production thereof.

BACKGROUND

Stand-up pouches are an increasingly popular packaging solution for many industries, including food, pet food and non-food sectors. Stand-up pouches are flexible and normally composed of plastics (such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and/or polyamide (PA)), aluminium or metallised films.
A stand-up pouch can be formed from a single web that is folded to form a bottom and two vertical side walls. Alternatively, three webs are used to form the two side walls and the bottom, respectively. The side walls at joined to each other by vertical seals. A sealing is also provided at the bottom such that pouch can stand up. The top of the stand-up pouch may also be sealed, often after filling. One end may also be provided with a re-closable zip. Sometimes, a handle, a euro slot and/or tear notches is/are provided at the top. The stand-up pouch may also be provided with a dispensing device, such as spout, e.g. for pouring. The spout may be provided with a re-closable cap.
US5465842 discloses A composite endless form for making flexible, windowed, form, fill and seal bags includes an endless strip of flexible, substantially opaque, paper-like material having a print side thereon with printed indicia thereon and an adhesive side, opposite the print side, with an adhesive thereon. The endless strip of paper-like material includes individual bag forms attached side-to-side thereon, each to be used for making a windowed bag, the endless-strip of paper-like material having a window opening cut in each individual bag form. The window openings are oblong and extend diagonal to a direction of elongation of the composite endless form. A heat-sealable film is adhered to the endless strip of paper-like material on the adhesive side thereof to cover substantially all of the adhesive side. The composite endless form is placed in a roll to be fed to form, fill and seal machines for making windowed bags.

SUMMARY

One object of the present is to provide stand-up pouch composed of a paper material, such as a laminate. Generally, paper is associated with less environmental concerns than plastics. Paper is a renewable resource and it has a lower carbon footprint than a plastic. Also, in some applications paper is preferred for its aesthetic appearance and tactile feel.
Further, the present inventors have realized that certain features of stand-up pouches are obtainable if the paper material is stretchable/extensible. For example, a stretchable paper allows for forming a three-dimensional pattern, such as a bulge or a relief, in the side walls of the stand-up pouch. The three-dimensional pattern may be provided for aesthetic reasons or branding. It may also provide a function, such an improved grip, added rigidity, improved dispensing or pouring, improved sealing function or increased volume. A stretchable paper may also facilitate the inclusion of a dispensing device, such as a spout, at the top.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which:

Fig 1A illustrates a first embodiment of the method of the first aspect of the present disclosure which is not in the scope of the invention.
Fig 1B illustrates a second embodiment of the method of the first aspect of the present disclosure which is not in the scope of the invention.
Fig 2 illustrates an embodiment of the method of the second aspect of the present disclosure which is not in the scope of the invention.
Fig 3 illustrates an embodiment of the method of the third aspect of the present disclosure according to invention.
Fig 4 illustrates an embodiment of the method of the fourth aspect of the present disclosure which is not in the scope of the invention.
Fig 5 illustrates an embodiment of the method of the fifth aspect of the present disclosure which is not in the scope of the invention.
Fig 6 illustrates an embodiment of a stand-up pouch according to the sixth aspect of the present disclosure which is not in the scope of the invention.

DETAILED DESCRIPTION

As a first, non-claimed, aspect of the present disclosure which is not in the scope of the invention, there is provided a method of forming a stand-up pouch, comprising the steps of:

a) providing a web structure having a w-shaped profile;
b) forming bottom and vertical seals such that a flat stand-up pouch having two superimposed side walls and a bottom is obtained;
c) press-forming at least part of the superimposed side walls; and
d) optionally filling and closing the stand-up pouch,

It is understood that the stretchable paper material stretches during the press-forming of step c)b such that a three-dimensional pattern in the side walls.
As also understood by the skilled person, the "vertical seals" of the present disclosure extend in the "vertical" direction when the stand-up pouch is standing.
In one embodiment of the first aspect, the web structure of step a) comprises two flanking portions composed of the stretchable paper material and a middle portion composed of the stretchable material or a different material, such as plastic or a non-stretchable paper-material. In such an embodiment, the flanking portions form the side walls and the middle portion forms the bottom during step b). Further, in such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the stretchable paper material to form the web structure having a w-shaped profile provided in step a).
In another embodiment, the web structure of step a) is composed of a single web of the stretchable paper material.
Accordingly, the method of the first aspect may comprise the steps of:

a) unwinding a stretchable paper material from a reel and folding the paper material such that it obtains a w-shaped profile;
b) forming bottom and vertical seals such that a flat stand-up pouch having two superimposed side walls and a bottom is obtained;
c) press-forming at least part of the superimposed side walls; and
d) optionally filling and closing the stand-up pouch.

The press-forming of step c) of the first aspect may for example be carried out by passing the at least part of the superimposed side walls between opposing rolls. Circumferential surfaces of the opposing rolls may be provided with protrusion(s) and/or recess(es) that correspond(s) to a three-dimensional pattern formed in the side walls by the press-forming. For example, the circumferential surface of a first roll may be provided with at least one protrusion that match(es) at least one recess provided on the circumferential surface of a second roll.
The opposing rolls may for example be connected to at least one motor. That means that the rolls may be connected to one motor each or a common motor. The motor(s) rotate(s) the rolls around their axes. The at least part of the circumferential surfaces of the rolls may be covered with a material that provides sufficient friction between the rolls and the superimposed sidewalls for the rolls to pull the stretchable material through the preceding steps. The opposing rolls may thus have two functions: press-forming the superimposed sidewalls and pulling the stretchable material through the method. However, the pulling is not necessarily the only force that moves the material through the method. For example, the reel from which the stretchable material is unwound may also be connected to a motor. Other parts of the machinery for carrying out the method may also be motorized.
The axes of the opposing rolls are preferably substantially vertical. Consequently, the side walls can for example have the same orientation during the press-forming as in a subsequent filling step.
In a stand-up pouch produced according to the first aspect, one side wall will have a positive (outwardly protruding) pattern, while the other side-wall will have the corresponding negative (inwardly protruding) pattern. Press-forming the superimposed side walls after bottom and vertical sealing according to the first aspect is beneficial as it is not disturbing the registering normally carried out in connection with the bottom and vertical sealing. Instead, the positions of the side walls relative each other and the vertical seals have already been fixed when press-forming is carried out.
As a second, non-claimed, aspect of the present disclosure which is not in the scope of the invention, there is provided a method of forming a stand-up pouch, comprising the steps of:

a) providing a web structure having a w-shaped profile, wherein a first flanking portion of the web structure corresponds to a first side wall of the stand-up pouch and a second flanking portion of the w-shaped paper material corresponds to a second side wall of the stand-up pouch;
b) press- or thermo-forming at least part of the first and/or the second flanking portion of the w-shaped web structure;
c) forming vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained; and
d) optionally filling and closing the stand-up pouch,
wherein the flanking portions are composed of a stretchable paper material.

In one embodiment which is not in the scope of the invention, the web structure of step a) comprises a middle portion composed of the stretchable paper material or a different materia, which middle portion forms the bottom during step c). The different material may for example be a non-stretchable paper material or a plastic material. In such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the stretchable paper material to form the web structure having a w-shaped profile provided in step a).
In another embodiment which is not in the scope of the invention, the web structure of step a) is composed of a single web of the stretchable paper material. Accordingly, the method of the second aspect may comprise the steps of:

a) unwinding a stretchable paper material from a reel and folding the paper material such that it obtains a w-shaped profile, wherein a first portion of the w-shaped paper material corresponds to a first side wall of the stand-up pouch and a second portion of the w-shaped paper material corresponds to a second side wall of the stand-up pouch;
b) press- or thermo-forming at least part of the first and/or the second portion of the w-shaped paper material;
c) forming vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained; and
d) optionally filling and closing the stand-up pouch.

Just as in the first aspect, the press-forming of the second aspect may for example be carried out by passing the stretchable material between opposing rolls, that can be motorized to pull the stretchable material.
Before the folding of the w-shaped profile, the paper material normally passes over at least one roll, such as three rolls. The purpose of the rolls is to tighten the paper material. However, there is a risk that such rolls destroy any three-dimensional pattern in the paper. As the w-shape is obtained after the rolls, it is thus beneficial to carry out press- or thermo-forming on the w-shaped paper material.
As a third, claimed, aspect of the present disclosure according to invention, there is provided a method of forming a stand-up pouch, comprising the steps of:

a) providing a web structure having a w-shaped profile;
b) forming vertical and bottom seals such that a flat stand-up pouch is obtained;
c) providing a mould cavity at an outer surface of a side wall of the stand-up pouch and applying an overpressure inside the pouch such that a portion of the side wall extends into the mould cavity to form a bulge or relief; and
d) optionally filling and closing the stand-up pouch,

In one embodiment of the third aspect, the web structure of step a) comprises two flanking portions composed of the stretchable paper material and a middle portion composed of the stretchable paper material or a different material. During step b) in such an embodiment, the flanking portions form side walls of the stand-up pouch and the middle portion forms a bottom of the stand-up pouch. In such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the stretchable paper material to form the web structure having a w-shaped profile provided in step a). The different material may for example be non-stretchable paper or plastic.
In another embodiment of the third aspect, the web structure of step a) is composed of a single web of the stretchable paper material. Accordingly, the third aspect may be a method of forming a paper stand-up pouch, comprising the steps of:

a) unwinding a stretchable paper material from a reel and folding the paper material such that it obtains a w-shaped profile;
b) forming vertical and bottom seals such that a flat stand-up pouch is obtained;
c) providing a mould cavity at an outer surface of a side wall of the stand-up pouch and applying an overpressure inside the pouch such that a portion of the side wall extends into the mould cavity to form a bulge or relief; and
d) optionally filling and closing the stand-up pouch.

It is understood that a pressure is applied inside the stand-up pouch in step d) of the third aspect, for example by means of a pressurized gas, such as pressurized air, from a compressor. In one embodiment of step d) of the third aspect, the stand-up pouch is heated before or when it is pressurized. Forming a three-dimensional pattern on the side walls according to the third aspect is beneficial as it is not disturbing the registering normally carried out in connection with the bottom and vertical sealing. Instead, the positions of the side walls relative each other and the vertical seals have already been fixed forming of the side wall is carried out. Further, the forming of the third aspect may be carried out in a modified version of the carousel that is used for filling up stand-up pouches in existing machines.
As a fourth, non-claimed, aspect of the present disclosure which is not in scope of the invention, there is provided a method of forming a stand-up pouch, comprising the steps of:

a) pressing at least one rolling wheel or roll against a stretchable paper material to form a pattern in the paper material;
b) arranging or folding the paper material such that it forms at least part of a web structure having a w-shaped profile;
c) forming vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained and at least part of the pattern is provided on at least one of the side walls; and
d) optionally filling and closing the stand-up pouch.

The pattern formed in step b) of the fourth aspect may for example be continuous and extend in the machine direction.
The pattern formed in step b) may also be a groove or dotted or dashed line extending in the machine direction. In such case, the pattern extends across a side wall of the stand-up pouch formed in step d) in a circumferential direction. For example, such a groove or dotted or dashed line would be obtained if using a rolling wheel in step b) of the fourth aspect. The groove would be obtained when the wheel has a circular cross-section. The dotted or dashed line would be obtained when the wheel has a star-shaped cross-section (see Fig 4).
In the method of the fourth aspect which is not in the scope of the invention, a counter roll may be used. In such case, the at least one wheel or roll in step b) is pressed against one side of the paper material and the counter roll is pressed against the other side of the paper material. The surface of the counter roll may have recesses or incisions corresponding to the shape of the pressing wheel(s) or protrusions on the surface of the pressing roll.
In one embodiment of the fourth aspect, the web structure of step b) comprises two flanking portions composed of the stretchable paper material and a middle portion composed of the stretchable paper material or a different material, such as non-stretchable paper or plastic. The flanking portions form the side walls and the middle portion forms the bottom during step c). Further, one of the flanking portions is the paper material comprising the pattern from step a). In such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the paper material to form the web structure having a w-shaped profile of step b). The two webs of paper material correspond to the flanking portions.
In another embodiment, the web structure of step b) is composed of a single web of the stretchable paper material. Accordingly, the third aspect may be a method of forming a paper stand-up pouch, comprising the steps of:

a) unwinding a stretchable paper material from a reel and pressing at least one rolling wheel or roll against the paper material to form a pattern in the paper material;
b) folding the paper material such that it obtains a w-shaped profile;
c) providing vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained and at least part of the pattern is provided on at least one of the side walls; and
d) optionally filling and closing the stand-up pouch.

As a fifth, non-claimed, aspect of the present disclosure which is not in the scope of the invention, there is provided a method of forming a stand-up pouch, comprising the steps of:

a) press- or thermo-forming a stretchable paper material to form a bulge or relief;
b) arranging or folding the paper material such that it forms at least part of a web structure having a w-shaped profile;
c) providing vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained, wherein the bulge or relief is provided on one of the side walls; and
d) optionally filling and closing the stand-up pouch.

In one embodiment of the fifth aspect, the web structure of step b) comprises two flanking portions composed of the stretchable paper material and a middle portion composed of the stretchable paper material or a different material, such as non-stretchable paper or plastic. The flanking portions form the side walls and the middle portion forms the bottom during step c). One of the flanking portions is the paper material comprising the pattern from step a). In such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the paper material to form the web structure having a w-shaped profile of step b). The two webs of the paper material correspond to the flanking portions.
In one embodiment of the fifth aspect, the web structure of step b) is composed of a single web of the stretchable paper material, which is the paper material comprising the pattern from step a). Accordingly, the fifth aspect may be a method of forming a paper stand-up pouch, comprising the steps of:

a) unwinding a stretchable paper material from a reel and press- or thermo-forming the paper material to form a bulge or relief;
b) folding the paper material such that it obtains a w-shaped profile;
c) providing vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained, wherein the bulge or relief is provided on one of the side walls; and
d) optionally filling and closing the stand-up pouch.

An important benefit of the fifth aspect is that it requires relatively few modifications of existing machinery for forming stand-up pouches. Thus, the fifth embodiment is relatively cost efficient.
Just as in the first aspect, the press-forming of the fifth aspect may for example be carried out by passing the stretchable material between opposing rolls, that can be motorized to pull the stretchable material.
As a sixth, non-claimed, aspect of the present disclosure which is not in the scope of the invention, there is provided a method of forming a paper stand-up pouch comprising a dispensing device, comprising the steps of:

a) providing a web structure having a w-shaped profile;
b) forming vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained, wherein the side walls are composed of a stretchable paper material; and
c) arranging a dispensing device between the side walls and closing the stand-up pouch, wherein the paper material of the side walls is stretched around the dispensing device such that the side walls are sealed to the dispensing device without creasing of the paper material.

In one embodiment of the method of the sixth aspect, the dispensing device is arranged between the side walls at the top of the stand-up pouch.
In one embodiment which is not in the scope of the invention, the web structure of step a) comprises two flanking portions composed of the stretchable paper material and a middle portion composed of the stretchable paper material or a different material, such as a non-stretchable paper material or plastic. During step b) of such an embodiment, the flanking portions form the side walls and the middle portion forms the bottom. Further, in such an embodiment, a bi-folded web (e.g. of the different material) may be arranged between two webs of the paper material to form the web structure having a w-shaped profile provided in step a).
In another embodiment of the sixth aspect which is not in the scope of the invention, the web structure of step a) is composed of a single web of the stretchable paper material. Accordingly, the sixth aspect may be a method of forming a paper stand-up pouch comprising a dispensing device, comprising the steps of:

a) unwinding a stretchable paper material from a reel and folding the paper material such that it obtains a w-shaped profile;
b) providing vertical and bottom seals such that a stand-up pouch having two side walls and a bottom is obtained;
c) arranging the dispensing device between the side walls (e.g. at the top of the stand-up pouch) and closing the top of the stand-up pouch, wherein the paper material of the side walls is stretched around the dispensing device such that the side walls are sealed to the dispensing device without creasing of the paper material.

The sixth aspect further includes a stand-up pouch comprising a bottom and two side walls, wherein the side walls are composed of a stretchable paper material and sealed to each other, a dispensing device is fixed between the side walls and at least a portion of the paper material of the side walls that contacts the dispensing device is stretched such that a crease-free sealing between the spout and the side walls is obtained.
In one embodiment of the stand-up pouch of the sixth aspect, the side walls are sealed to each other at a top of the stand-up pouch and the dispensing device is fixed between the side walls at the top.
The dispensing device of the sixth aspect is for example arranged in the corner between a vertical edge and a sealed top of the stand-up pouch.
The dispensing device may for example be a spout. Further, the dispensing device may comprise a screw top, a flip top, a snap on, a rolling ball, spray top, trigger/pump spray, a valve closure, tamper evident closure, a cork, an plug, a seal, a push pull or a combination of two or more of these. Thus, the spout may for example be provided with a re-closable cap. The skilled person is also aware of other dispensing devices through which the contents of the stand-up pouch may be obtained by the user.
One or both of the side walls of the stand-up pouch of the sixth aspect may be provided with an inwardly or outwardly protruding pattern. Such a pattern may be formed according to any one of the above methods.
Press-forming according to the present disclosure may comprise forming the paper-material between "female tool" comprising a cavity and a "male tool" that are pressed against each other. The male tool may comprise a punch. As an example, the position of the female tool may be fixed while the male tool/punch is pressed against it. Alternatively, the position of the male tool/punch may be fixed while the female tool is pressed against it. In another example, the female tool and the male tool/punch are moved against each other.
The male tool may also be a rotating press roll and the female tool may be a rotating counter roll.
The three-dimensional shape of the pattern obtained during press-forming may thus correspond to the shape of the punch of a male tool. In such case, it is possible, but not necessary that the three-dimensional shape also corresponds to the shape of the inside of the female cavity. The three-dimensional shape of the pattern obtained during press-forming may also correspond to a pattern on the surface of a male press roll.
In thermo-forming according to the present disclosure, the paper material is heated and forced into a negative mould/female cavity by means of negative or positive pressure, i.e. by means of a pressurized gas or "vacuum". The thermo-formed pattern in the paper material thus corresponds to the shape of the female cavity.
Paper is porous. Therefore, vacuum-forming according to the present disclosure normally requires that the pater material is coated or has a laminate structure (see below). However, the force obtained by vacuum is often insufficient for stretching the paper material. When thermo-forming is employed, it is therefore generally preferred to use positive pressure as in the third aspect.
In the first, second and fifth embodiment of the present disclosure, press-forming is more preferred than thermo-forming.
During the press- or thermo-forming of the present disclosure, the paper material stretches to obtain the intended three-dimensional shape or pattern. For example, the paper stretches to form a decorative embossment, grip-improving protrusions or a volume-increasing bulge. To facilitate the stretch during press- or thermo-forming according to the present disclosure, heat may be applied to the paper material before and/or during the forming step. Accordingly, the press-forming tools, in particular the male press-forming tools, may be heated. The female press-forming tools may be cooled. Thus, some embodiments of the press-forming of the present disclosure may be referred to as thermoforming. It may be particularly beneficial to apply heat when the stretchable paper material comprises a polymer coating or is a laminate comprising a plastic layer. Coatings and laminates are further discussed below.
The paper material of the present disclosure is stretchable. The stretchability of the paper material is preferably at least 5 % in both the machine direction (MD) and the cross direction (CD). For example, it may be at least 6 or 7 % in both directions. In one embodiment it is at least 7 % in the CD and at least 14 % in the MD. An example of a stretchable paper suitable for the method of present invention is FibreForm® marketed by BillerudKorsnäs AB. The strechability may for example be measured according to standard ISO 1924-3.
The grammage of the stretchable paper material may for example be 40 - 400 g/m², such as 50-300 g/m², such as 60-250 g/m², such as 70-200 g/m². A higher grammage (i.e. ≥ 100 g/m²) may be beneficial as it results in a stiffer and i.e more robust stand-up pouch. A lower grammage (i.e. < 100 g/m²) may also be beneficial as it is results in a lighter and more flexible stand-up pouch. Further, paper material of lower grammages is generally cheaper.
The paper material of the present disclosure may be composed of a single layer. However, it may also be a laminate composed of a plurality of paper layers, such as two, three or four layers. The laminate may also comprise one or more plastic layers. Such a laminate may be obtained by gluing a plastic or barrier film to the paper.
The paper material may also comprise a coated paper. Several coating techniques are known to the skilled person and the present disclosure is not limited to anyone of them.
The plastic film(s) of the laminate or the coating(s) of the coated paper normally has/have one or more barrier properties. Examples of barrier properties include grease barrier, gas barrier and moisture barrier properties. Such barrier properties are for example of interest when food or liquids are packaged in the stand-up pouch.
A coating or laminate layer of one or more of the following materials may enable heat-sealing during bottom, vertical and/or top sealing: PE (e.g. HDPE, LLDPE or LDPE), PLA, PA, PET, PP and Lacquer hot melt. Further, the coating or laminate layer may be a dispersion, a bio-based polymer, a bio-based binding material or a glue.
A benefit of PE and PP is that they are also moisture barriers.
A particularly preferred material for forming the stand-up pouches of the present disclosure is a stretchable paper provided with a polyolefin multilayer barrier film on the side forming the inside of the pouch. The polyolefin multilayer preferably comprises a layer of EVOH, which is a gas barrier, sandwiched between two layers of polyolefin, such as PE or PP. The barrier layer may also be a multilayer PA-polymer structure (PA is also a gas barrier).
Such preferred materials often give excellent protection against light, gas, humidity and aroma.
In the methods of the present disclosure, a single paper web may be folded such that it obtains a w-shaped profile. Such folding is an established step in the manufacture of stand-up pouches.
Alternatively, three webs are employed, wherein the first web corresponds to a first side wall of the stand up pouch, the second web corresponds to a second side wall of the stand up pouch and the third web corresponds to a bottom of the stand-up pouch. In such case, at least one of the first and the second web is composed of the stretchable paper material. Often, both the first and the second web are composed of the stretchable paper material. The third web may however be composed of a different material. Accordingly, the bottom of the stand-up of the present disclosure may for example be composed of a transparent plastic material. The three webs are arranged to form a w-shaped in a manner known in the field of manufacturing plastic stand-up pouches
Similarly, the bottom sealing (to form the bottom of the stand-up pouch and allow it to stand when filled), vertical sealing, top sealing/closing and spout arrangement are well known steps in the field of plastic stand-up pouches that without undue burden can be implemented by the skilled person carrying out the methods of the present disclosure.
One example of a sealing operation is heat sealing. Thus, the side of the paper material that forms the inside of the stand-up pouch of the present disclosure may be provided with a heat-sealable coating or layer. Examples of such a coating or layer are provided above. Typically, the heat-sealing process requires that both sides of the paper material are not provided with the heat-sealable coating or layer.
For example, the skilled person knows that in heat sealing, recesses or holes may be provided in the material forming the bottom of the stand-up pouch, which recesses or holes allows portions of the side walls at the bottom to be sealed to each other and the characteristic stand-up pouch bottom to be formed.
Instead or having a heat-sealable coating or layer covering the inside of the pouch, a glue or pressure sensitive lacquer may be applied during the sealing process in a known manner.
Another example of a "cold sealing" method is dry crimping, which is used in the production coffee filters or tea bag envelopes.
The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Fig 1A illustrates a first embodiment of the method of the first aspect of the present disclosure which is not in the scope of the invention. In the first embodiment, a stretchable paper material 101 is unwound from a paper reel 102. The paper 101 passes over at least one roll 103 before it is folded to form a w-shape 104. One purpose of the roll(s) 103 is normally to tighten the paper material. The lower end of the w-shaped paper is then sealed 105 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 106. The vertical seals 107 will after cutting become the vertical edges 108 of the finished stand-up pouches 109 that joins first side walls 110a to second side walls 110b. Bottom sealing 105 and vertical sealing 106 are well known operations in the production of stand-up pouches. An area between two vertical seals 107, which thus comprises two superimposed layers of the paper material, is then subjected to press-forming 111, during which certain portions of the superimposed layers are stretched, such that a protruding pattern 112a is formed on one side corresponding to the first side walls 110a and an inverted recessed pattern 112b is formed on the other side corresponding to the second side walls 112b. A result of the press-forming 111 is thus that the same pattern is projecting outwardly 112a on one side wall 110a of the pouches 109 and inwardly 112b on the opposed side wall 110b.
After press-forming 111, a spout 113 is optionally arranged at the upper end, which is still open, in a spout arrangement step 114. The spout is further discussed below in connection with Fig 6.
After bottom- and vertical sealing 105, 106, press-forming 111 and the optional arrangement 114 of a spout 113, the pouches are normally filled 115 through the still open top/upper end. After the filling 115, the upper end is normally closed 116. The closing operation 116 may be the same type of sealing as the bottom sealing 105 and vertical sealing 106. Alternatively, the closing 116 may comprise an arrangement of a re-closable zip, in particular when no spout 113 is arranged. If neither a spout 113 nor a re-closable zip is arranged, tear notches may be provided at the top, e.g. by punching, to facilitate opening of the closed stand-up pouch. However, in one embodiment, the stand up pouch is provided with a re-closable zip, sealed at the very top, and provided with tear notches between the re-closable zip and the sealed top. In such case, the user tears the pouch open the first time and then uses the re-closable zip for further openings and closings.
Before or after the filling 115 and closing 116, vertical cutting (not shown) of the vertical seal 107 is performed such that the vertical seal 107 is divided into the vertical edges 108a, 108b of individual stand-up pouches 109.
Fig 1B illustrates a second embodiment of the method of the first aspect of the present disclosure which is not in the scope of the invention. Just as in the first embodiment, a stretchable paper material 101 is unwound from a paper reel 102 in the second embodiment. The paper 101 passes over at least one roll 103 before it is folded to form a w-shape 104. One purpose of the roll(s) 103 is normally to tighten the paper material. The lower end of the w-shaped paper is then sealed 105 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 106. The vertical seals 107 will after cutting become the vertical edges 108 of the finished stand-up pouches 109 that joins first side walls 110a to second side walls 110b. Bottom sealing 105 and vertical sealing 106 are well known operations in the production of stand-up pouches. An area between two vertical seals 107, which thus comprises two superimposed layers of the paper material, is then subjected to roll press-forming, during which certain portions of the superimposed layers are stretched, such that a protruding pattern 112a is formed on one side corresponding to the first side walls 110a and an inverted recessed pattern 112b is formed on the other side corresponding to the second side walls 112b. The press-forming is achieved passing the superimposed layers between two opposing rolls 120a, 120b. The axes of the generally cylindrical rolls 120a, 120b are vertical. The circumferential surface 121a of a first roll 120a comprises a recess 122a corresponding to the protruding pattern 112a. The circumferential surface 121b of a second roll 120b comprises a protrusion 122b corresponding to the recessed pattern 112b. The result of the roll press-forming is thus that the same pattern is projecting outwardly 112a on one side wall 110a of the pouches 109 and inwardly 112b on the opposed side wall 110b.
The opposing rolls 120a, 120b are connected to at least one motor such that the rolls can pull the material through the proceedings steps. To facilitate this pulling function, at least part of the circumferential surfaces 121a, 121b of the rolls 120a, 120b may be covered by rubber or another material that provides for a relatively high friction coefficient between the rolls 120a, 120b and the material of the superimposed layers.
After roll press-forming, a spout 113 is optionally arranged at the upper end, which is still open, in a spout arrangement step 114. The spout is further discussed below in connection with Fig 6.
After bottom- and vertical sealing 105, 106, roll press-forming and the optional arrangement 114 of a spout 113, the pouches are normally filled 115 through the still open top/upper end. After the filling 115, the upper end is normally closed 116. The closing operation 116 may be the same type of sealing as the bottom sealing 105 and vertical sealing 106. Alternatively, the closing 116 may comprise an arrangement of a re-closable zip, in particular when no spout 113 is arranged. If neither a spout 113 nor a re-closable zip is arranged, tear notches may be provided at the top, e.g. by punching, to facilitate opening of the closed stand-up pouch. However, in one embodiment, the stand up pouch is provided with a re-closable zip, sealed at the very top, and provided with tear notches between the re-closable zip and the sealed top. In such case, the user tears the pouch open the first time and then uses the re-closable zip for further openings and closings.
Before or after the filling 115 and closing 116, vertical cutting (not shown) of the vertical seal 107 is performed such that the vertical seal 107 is divided into the vertical edges 108a, 108b of individual stand-up pouches 109.
Fig 2 illustrates an embodiment of the method of the second aspect of the present disclosure which is not in the scope of the invention. In the method, a stretchable paper material 201 is unwound from a paper reel 202. The paper 201 passes over at least one roll 203 before it is folded to form a w-shape 204. The w-shaped paper is subjected to press-forming 225, during which (a) certain portion(s) the paper material 201 is/are stretched. In the embodiment of Fig 2, press-forming is carried by means of two pressing arrangements, each comprising a male tool 226a and female tool 226b, which are pressed against each other to form an outwardly protruding pattern 212 on portions 227a, 227b of the w-shaped paper material that corresponds to the side- walls 210a, 210 b of the stand-up pouch 209.
A male tool 226a and a corresponding female tool 226b are not necessary for achieving the protruding pattern. In one embodiment, the press-forming arrangement comprises only a male tool 226a for shaping the protruding pattern 212. In such an embodiment, the press-forming arrangement normally comprises a clamp to facilitate the stretch of the paper. Alternatively, thermo-forming is carried out instead of press-forming. In such case, a female tool 226b forms the shape of the protruding pattern 212. A pressurized gas, such as air, may provide the force which forces the paper material 201 to stretch within a negative mould of the female tool 226b such that the protruding pattern 212 is formed. In another embodiment, negative pressure or "vacuum" provides the force which forces the paper material 201 to stretch within a negative mould of the female tool 226b. Such forming is normally referred to as vacuum forming.
It is not necessary that both side- walls 210a, 210b are provided with the outwardly protruding pattern 212. In the press- and thermo-forming embodiments discussed above, only one of the portions 227a, 227b of the w-shaped paper may thus be subjected to press-forming, which results in that only one of the side- walls 210a, 210b comprises an outwardly protruding pattern 212.
The lower end of the w-shaped paper is then sealed 205 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 206. The vertical seals 207 will after cutting become the vertical edges 208 of the finished stand-up pouches 209 that joins first side walls 210a to second side walls 210b.
After bottom 205 and vertical 206 sealing, a spout 213 is optionally arranged at the upper end, which is still open, in a spout arrangement step 214. The spout is further discussed below in connection with Fig 6.
After bottom- and vertical sealing 205, 206 and the optional arrangement 214 of a spout 213, the pouches are normally filled 215 through the still open top/upper end and then closed 216 as described above in connection with Fig 1. Also, cutting is normally performed as described above in connection with the first aspect.
Fig 3 illustrates an embodiment of the method of the third aspect of the present disclosure according to the invention. In the method, a stretchable paper material 301 is unwound from a paper reel 302. The paper 301 passes over at least one roll 303 before it is folded to form a w-shape 304. The lower end of the w-shaped paper is then sealed 305 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 306. The vertical seals 307 will after cutting become the vertical edges 308 of the finished stand-up pouches 309 that joins first side walls 310a to second side walls 310b.
After press-forming 311, a spout 313 is optionally arranged at the upper end, which is still open, in a spout arrangement step 314. The spout is further discussed below in connection with Fig 6.
After the sealing operations 305, 306 and before or after the optional arrangement 314 of a spout 313, vertical cutting 330 of the vertical seal 307 is performed such that the vertical seal 307 is divided into the vertical edges 308a, 308b of individual stand-up pouches 309.
After cutting, a mould 331 comprising at least one negative cavity 332 is arranged around the stand-up pouch 309. Fig 3 shows a mould 331 in two parts in an opened state. Alternatively, the mould may be a hollow one-piece mould into which the stand-up pouch is inserted. When the stand-up pouch is enclosed or surrounded, the inside of the stand-up pouch is pressurized 333. In the pressurized state, a portion of a side- wall 310a, 310b extends in the negative cavity 332 of the mould 331. In other words, the stand-up pouch 309 is inflated in the negative cavity 332 such that a outwardly protruding pattern 312 is formed.
After the outwardly protruding pattern(s) 312 has/have been formed, the pouches are normally filled 315 through the still open top/upper end. After the filling 315, the pouches 309 are normally closed 316 as described above in connection with the first aspect.
The forming of the outwardly protruding pattern(s) 312, the filling 315 and the closing 316 may be carried out in a carousel. Today, carousels are used for filling and closing of plastic stand-up pouches.
Fig 4 illustrates an embodiment of the method of the fourth aspect of the present disclosure which is not in the scope of the invention. In the method, a stretchable paper material 401 is unwound from a paper reel 402. The paper material 401 passes over a forming roll 403 comprising pressing wheels 440a, 440b before it is folded to form a w-shape 404. One or more normal rolls (without pressing reels) may be arranged between the paper reel 402 and the forming roll 403.
The forming roll 403 is rotatably arranged such that it rolls during production. The pressing wheels 440a, 440b form two continuous grooves 441a, 441b in the paper material 401. The grooves 441a, 441b extend in the machine direction. In portions 427a, 427b of the w-shaped paper material that corresponds to the side- walls 410a, 410b of the stand-up pouch 409, the grooves 441a, 441b are thus horizontally extending and outwardly projecting protrusions, which in the finished stand-up pouch form a circumferential and outwardly protruding pattern 412a, 412b.
The wheels 440a, 440b has a circular cross-section. Alternative wheels 480, 481 may have a star-shaped cross-section with rounded corners. Such alternative wheels 480, 481 result in a dotted circumferential and outwardly protruding pattern on the side walls 410a, 410b of the stand-up pouch.
In yet another embodiment, an alternative forming roll 490 that comprises no pressing wheels, but a surface pattern 491 for forming the paper material 401 is used. In such an embodiment, the protruding pattern of the side walls of the stand-up pouch is not necessarily extending in the horizontal/circumferential direction.
A counter roll 495 may assist the forming roll 403, 490 in forming the paper material 401. The surface pattern of the counter roll 495 may be an inverted version of the surface pattern of the forming roll 403. The counter roll 495 of Fig 4 thus has recesses/ incisions 496a, 496b corresponding to the wheels 440a, 440b of the pressing roll 403. The placement, width and depth of the recesses/ incisions 496a, 496b are thus adapted to the placement, width and height of the wheels 440a, 440b such that the wheels 440a, 440b can run in the recesses/ incisions 496a, 496b when the paper material is provided between the pressing roll 403 and the counter roll.
After forming by means of the forming roll 403, 490 and folding to obtain the w-shape 404, the lower end of the w-shaped paper is sealed 405 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 406. The vertical seals 407 will after cutting become the vertical edges 408 of the finished stand-up pouches 409 that joins first side walls 410a to second side walls 410b.
After bottom and vertical sealing 405, 406, a spout 413 is optionally arranged at the upper end, which is still open, in a spout arrangement step 414. The spout 413 is further discussed below in connection with Fig 6.
After bottom- and vertical sealing 405, 406 and the optional arrangement 414 of a spout 413, the pouches are normally filled 415 through the still open top/upper end. After the filling 415, the pouches 409 are normally filled 415 through the still open top/upper end and then closed 416 as described above in connection with the first aspect. Also, cutting is normally performed as described above in connection with the first aspect.
Fig 5 illustrates an embodiment of the method of the fifth aspect of the present disclosure which is not in the scope of the invention. In the method, a stretchable paper material 501 is unwound from a paper reel 502. The flat paper material 501 is subjected to press-forming 525, during which (a) certain portion(s) the paper material 501 is/are stretched to form a protruding pattern 512. In the embodiment of Fig 5, press-forming is carried by means of a pressing arrangement comprising a male tool 526a and female tool 526b, which are pressed against each other to form an outwardly protruding pattern 512 on portions 527a, 527b of the later form w-shaped paper material that corresponds to the side- walls 510a, 510b of the stand-up pouch 509. Embodiments of and alternatives to the press-forming shown in Fig 5 are discussed above in connection with the second aspect.
Before and/or after the press-forming 525, the paper material 501 may pass over at least one roll 503.
The paper material is then folded such that it obtains the w-shape 504. The lower end of the w-shaped paper is sealed 505 to form a stand-up pouch bottom, which is often referred to as "bottom sealing". The paper is then subjected to vertical sealing 506. The vertical seals 507 will after cutting become the vertical edges 508 of the finished stand-up pouches 509 that joins first side walls 510a to second side walls 510b.
After bottom and vertical sealing 505, 506, a spout 513 is optionally arranged at the upper end, which is still open, in a spout arrangement step 514. The spout 513 is further discussed below in connection with Fig 6.
After bottom- and vertical sealing 505, 506 and the optional arrangement 514 of a spout 513, the pouches are normally filled 515 through the still open top/upper end. After the filling 515, the pouches 509 are normally filled 515 through the still open top/upper end and then closed 516 as described above in connection with the first aspect. Also, cutting is normally performed as described above in connection with the first aspect.
Fig 6 shows an embodiment of a stand-up pouch 609 composed of stretchable paper according to the sixth aspect of the present disclosure which is not in the scope of the invention. A spout 613 is arranged between the side walls 610a, 610b at the top of the stand-up pouch 609.
The side walls 610a, 610b comprises a protruding pattern 612, 612, which could be formed because the paper material is stretchable.
The spout 613 may comprise an anchoring portion 660 to which the side walls 610a, 610b are fixed. The anchoring portion 660 is provided with ribs or grooves 661 that facilitate the fixation. When the spout 613 is arranged, the paper material of the side walls 610a, 610b stretches around the anchoring portion 660. If the anchoring portion 660 is provided with the ribs or grooves 661, the paper material also stretches over the ribs 661 or the ridges between the grooves 661. Consequently, the ribs or grooves 661 are seen as waves 664 in the side walls 610a, 610b at the site of fixation. Thanks to the stretchability of the paper material, the side walls 610a, 610b are sealed to the spout 613 without creasing.
The spout 613 may be provided with reclosable cap 662. The cap 662 may be hingedly attached to a pouring pipe 663 of the spout 613.

Claims

Method of forming a stand-up pouch (309), comprising the steps of:
a) providing a web structure having a w-shaped profile (304);

b) forming vertical (307) and bottom seals such that a flat stand-up pouch is obtained;

c) providing a mould cavity (332) at an outer surface of a side wall (310a, 310b) of the stand-up pouch and applying an overpressure inside the pouch such that a portion of the side wall extends into the mould cavity to form a bulge or relief; and

d) optionally filling and closing the stand-up pouch,
wherein the side walls is composed of a stretchable paper material.
Method according to claim 1, wherein the stretchability of the stretchable paper material is at least 5 % in the machine direction (MD) and at least 5 % in the cross direction (CD).
Method according to any one of the preceding claims, wherein the side of the stretchable paper material that forms the inside of the stand-up pouch is provided with a heat-sealable coating or film.