WO2025238161A1

WO2025238161A1 - A system for continuous formation of a web of material comprising a coating layer, a barrier layer and a substrate layer

Info

Publication number: WO2025238161A1
Application number: PCT/EP2025/063422
Authority: WO
Inventors: Marco Borello; Marco COTTI; Marco FILOTTI; Elvo MERLO
Original assignee: Bobst Italia SpA
Current assignee: Bobst Italia SpA
Priority date: 2024-05-16
Filing date: 2025-05-15
Publication date: 2025-11-20
Anticipated expiration: 2026-11-16

Abstract

A system (2) for continuous formation of a web (4) of material comprising a coating layer (14), a barrier layer (12) and substrate layer, the system (2) comprising: a coating station for associating a coating layer (14) with a web of the barrier layer (12) and substrate layer; a transmission system (8) arranged for transmission of the web (4) relative the coating station, the transmission system (8) comprising a plurality of rollers (50) for rotary engagement with said web (4), and electrical circuitry (10) arranged to determine a strain parameter of said web based on a difference in rotation of a plurality of the rollers (50) for assessing the integrity of the barrier layer (12).

Description

A SYSTEM FOR CONTINUOUS FORMATION OF A WEB OF MATERIAL COMPRISING A COATING LAYER, A BARRIER LAYER AND A SUBSTRATE LAYER

TECHNICAL FIELD

The present disclosure relates to a system for continuous formation of a web of material comprising a coating layer, a barrier layer and substrate layer. In particular, the disclosure relates to an arrangement for measuring a strain of said web.

BACKGROUND

US7763361 B2 and US8663758 B2 disclose manufacturing line configurations for the formation of webs of multi-layered flexible film structures, which may be used in flexible packaging, e.g. for foodstuffs.

The multi-layered flexible film structures comprise a metalized film (which may be referred to as a barrier layer) applied to a polymer layer (which may be referred to as a substrate layer). The metalized film may be applied using a physical vapor deposition process whereby the metal used for the coating is vaporized and deposited onto a sheet of polymer layer, all under vacuum conditions. The metallized film has a shiny, opaque appearance and excellent barrier properties against moisture, oxygen and light transmission. The polymer layer may comprise Mediumdensity polyethylene (MDPE), polypropylene (OPP) or polyethylene terephthalate (PET), and provides the primary load carrying function for the multi-layered flexible film.

A coating layer may be applied to the web of metallized film and polymer layer, which may provide graphics or other capability. A graphics capability may enable a consumer to identify the packaged product or details of said product, and may be provided by an ink layer.

The barrier layer is comparatively low in flexibility relative to the substrate layer. Consequently, during processing of the web (e.g. when applying the coating layer), the barrier layer may not be able to absorb an elongation of the substrate layer, and may break in some locations. This may result in flaws in the barrier property of the final product.

It is therefore desirable to determine a condition of excessive strain of the barrier layer. Prior art approaches for measurement of strain of a web include: strain gauges, which may be attached to a surface of the web; load cells, which may be integrated into rollers or supports and measure the force or load applied to the material, and; laser or optical sensors, which use laser or light beams to measure deformation or movement in the material by changes in the reflected light. However, these methods predominantly assess the strain of the web as a whole, focusing primarily on the strain of the substrate layer to ensure proper handling during coating or laminating processes. Consequently, they tend to overlook the strain specific to the barrier layer. Therefore, in spite of the effort already invested in the development of systems further improvements are desirable.

SUMMARY

The present disclosure provides a system for continuous formation of a web of material comprising a coating layer, a barrier layer and substrate layer, the system comprising: a coating station for associating (e.g. forming on) a coating layer with a web of the barrier layer and substrate layer; a transmission system arranged for handling of the web (e.g. for transmission of the web relative the coating station), the transmission system comprising a plurality of rollers for rotary engagement with said web, and electrical circuitry arranged to control the roller rotation and the web tension for ensuring that the coating layer is formed properly. The electrical circuitry is arranged to determine a strain parameter related to the strain of said web. The strain is derived from a differential rotation of a plurality of the rollers and is used to assess the integrity of the barrier layer from the value of said strain parameter. The assessment based on the strain parameter is needed because the barrier layer of the present disclosure has a young modulus larger than the young modulus of the substrate layer, and thus, a strain value which might be acceptable for the substrate may cause rupture in the barrier layer, and/or may damage the bound between the substrate and the barrier layer.

By implementing a web strain determination approach based on a rotation of the rollers(s) a convenient and reliable strain determination system may be derived, which may also be conveniently retrofittable to existing manufacturing lines. For example, in a system that already measures roller rotation, to implement the strain determination approach would require electrical circuitry (e.g. of an available processing resource already as part of the system) to determine the strain parameter from the measured rotation. Alternatively, roller rotation measurement may be implemented on an existing system with rotary encoders or other suitable system.

In embodiments, the electrical circuitry is implemented as one or more processors, which are configured to implement the disclosed steps performed by the system (e.g., including determining the stain parameter) and/or the steps performed by process stations and the transmission system to execute a formation process. The processors may execute program code stored on electronic memory and/or may execute programable logic, e.g., as a logic array, gate array, structured array etc.

In embodiments, the electrical circuitry is configured to determine the strain parameter based on a time-based integral of a difference in rotation of two or more of the rollers.

By implementing the strain parameter to be determined using a difference in two rollers rotation, which are spatially separated with respect to the manufacturing line, accurate strain measurement of the portion of the web between the rollers may be obtained. As used herein the term “a difference in rotation” may refer to an angular velocity or the rollers or a peripheral speed of the rollers, e.g. the speed experienced at an interface with the roller and the web. Such an arrangement may therefore account for rollers of the same or a different diameter. The rotation of the roller may refer to the rotation being measured directly at the roller or indirectly via a rotationally connected member (e.g. a driver of a drive system, which may include a DC stepped motor with integrated rotary position determination).

In embodiments, the electrical circuitry implements a control system for control of the roller rotation, e.g. proportional, integral and/or differential (PID) control. In embodiments, the input of the control system is based on a load of a load cell arranged to determine a load of the web and/or a position of a dancer roller. In embodiments, wherein the strain parameter is determined based on the integral component of the PID control or other control system. By implementing PID (or PI) control to determine a difference in roller rotation, the integral component of such an existing control system may conveniently be repurposed for strain determination.

In embodiments, the electrical circuitry is configured to determine based on the strain parameter if a strain threshold has been crossed. A threshold determination may be implemented to identify when the strain has crossed an acceptable amount. The threshold may be set by empirical data, and the determination may be based on using the actual strain, the strain parameter or other numerical quantity related thereto.

In embodiments, in response to said threshold being crossed, the electrical circuitry is configured to provide a notification to a user interface. For example, the user interface may comprise one of more of the following: visual feedback; audible feedback; or haptic feedback.

In embodiments, in response to said threshold being crossed, the electrical circuitry is configured to implement storage of an entry in a database associated with a particular web. For example, an electronic record may be formed that relates the strain parameter to a particular cross-section of a portion of the web. In this way, a record of the points of the web where the strain has been exceeded may be derived.

In embodiments, in response to said threshold being crossed, the electrical circuitry is configured to implement halting of web formation is implemented. For example, halting may comprise one or more of the following: halting of an operation of a station (e.g. coating or drying); and halting of the transmission system. In this way, the strain of the relevant section may be inspected and/or the web may be replaced.

In embodiments, in response to said threshold being crossed, the electrical circuitry is configured to determine an adverse condition of the system associated with the crossing of the threshold. The adverse condition may comprise a setting of the system that causes too high a strain in the web. Examples of which include: excessively high drying temperature/drying rate from the drying station; too great an acceleration applied to a roller.

In embodiments, the electrical circuitry is configured to: associate the strain parameter with one or more cross-sectional portions of the web. By linking a cross-sectional position in the web to the strain parameter e.g., as an electronic record or a physical record, a record of the quality at points of the web may be provided, which may be used for example, to excise portions of the web where an acceptable strain has been exceeded.

In embodiments, the coating station is configured to apply the coating layer to the web comprising metal-based barrier layer and a plastic-based substrate layer.

In embodiments, the coating station is configured to apply the coating layer to the web comprising aluminimum-based, or aluminium oxide based barrier layer and a Polyethylen-based substrate layer.

In embodiments, the at least one of the rollers is driven to rotate by a drive system to implement independent control (e.g. so that the rotation of the roller can rotate independently of any other roller) of the rotation of the roller. The drive system may for example comprise a drive system that includes a motor (e.g. an electrical or hydraulically operated motor) and optionally a gear system to couple the motor to the roller.

In embodiments, the system comprises a drying station arranged downstream of the coating station, and the strain parameter determined for a portion of the web during and/or subsequent the coating station, including before and/or during and/or subsequent drying from the drying station. By implementing strain determination following coating and/or drying, web contraction due to these processes may be accurately controlled to prevent the strain from exceeding a threshold.

In embodiments, the system comprises the web comprising the barrier layer, the substrate layer, and optionally the coating layer.

In embodiments, present disclosure provides a web comprising the barrier layer, the substrate layer, and optionally the coating layer formed by the system of any preceding embodiment, or another embodiment disclosed herein.

The present disclosure provides a web comprising a coating layer, a barrier layer, and a substrate layer, and; a record of a strain parameter for one or more cross-sectional portions of the web.

The present disclosure provides a method of determining a strain of a web for assessing the integrity of the barrier layer, the method comprising: determining a difference/change in rotation of one or a plurality of rollers, which are implemented to handle a web comprising a barrier layer and a substrate layer, and; determining a strain parameter related to a strain of the web based on the determined difference/change rotation of one or a plurality of rollers. In embodiments, the web comprises the coating layer.

The present disclosure provides a method of forming a web comprising associating a coating layer with a web of a barrier layer and a substrate layer, the method comprising: forming with a coating station the coating layer and associating with the web of the barrier layer and the substrate layer, and; determining the strain parameter according to preceding method.

In embodiments, the method comprises: associating the strain parameter with one or more crosssection portions of the web. In embodiments, the method comprises discarding a portion of the web for which the strain parameter has crossed the threshold. In embodiments, the method comprises determining based on the strain parameter if a strain threshold has been crossed.

The present disclosure provides electrical circuitry or a computer program comprising program code executable on one or more processors, to implement the method of any preceding embodiment, or another embodiment disclosed herein.

The present disclosure provides a method of upgrading an existing system for continuous formation of web of material comprising a coating layer, a barrier layer, and a substrate layer, the system comprising: coating station for associating a coating layer with a web of the barrier layer and the substrate layer; a transmission system arranged for transmission of the web relative the coating station, the handling system comprising a plurality of rollers for rotary engagement with said web, the method comprising: implementing electrical circuitry arranged to determine a strain parameter related to a strain of said web based on a rotation (e.g. a change/difference in rotation) of one or a plurality of the rollers.

BRIEF DESCRIPTION OF FIGURES

Aspects, features and advantages of embodiments of the present disclosure will become apparent from the following detailed description of embodiments in reference to the appended drawings in which like numerals denote like elements.

Figure 1 is a block system diagram showing a system for continuous formation of a web of material comprising a process stations, a transmission system, and electrical circuitry.

Figure 2 is a schematic diagram showing the system of figure 2 in more detail.

DETAILED DESCRIPTION OF EMBODIMENTS

Before describing several embodiments of the system, it is to be understood that the system is not limited to the details of construction or process steps set forth in the following description. It will be apparent to those skilled in the art having the benefit of the present disclosure that the system is capable of other embodiments and of being practiced or being carried out in various ways.

The present disclosure may be better understood in view of the following explanations:

As used herein the term “system” may refer to an arrangement, that may consist of the or be part of a manufacturing line for execution of a formation process, in which the formation of a web of material is provided. As used herein the term “formation process” may refer to a process executed by the system to at least partially form the web. The system may be for continuous formation of the web. As used herein the term “continuous” may refer to as meaning part of a manufacturing line for a material web, in which the web is continuously formed by transmission through sequential process stations, rather than discrete sheet formation process. The system may comprise one or more process stations for formation and/or processing of the web, examples of which include: a barrier layer forming/plating station (for formation and/or association of a barrier layer with a substrate layer); a coater station for associating a coating with the web; a laminator station for lamination of the web, and; a drying/heating station for drying and/or heating of the web (e.g. following coating/laminating/associating the barrier layer). The system may include a transmission system for transmission of the web between the process stations. The system may include or be controlled by electrical circuitry as defined herein.

As used herein the term “web” may refer to a thin flexible multi layered-laminate that can be stored as a roll. An end result of the web may be for sheet manufacturing of packaging, for example food packaging. In food packaging any strain related crack/discontinuity in the barrier represents a loss of integrity of the barrier layer. The web may include a substrate layer and a barrier layer. The web may include a coating layer and/or a laminated layer.

As used herein the term “transmission system” may refer to an arrangement for transmission/handling of the web between the process stations of the system. The transmission system may be implemented by rollers and optionally conveyor belts or other suitable system. As used herein the term “rollers” may refer to a circular section member arranged to rotate about an axis of rotational symmetry, with a periphery disposed to engage the web. A roller may be driven by a drive system to support and impart, at the periphery, translational motion. A roller may be free-rotating, and not driven by a drive system, in which case it may simply support the web.

As used herein the term “strain parameter” may refer to a numerical quantity that comprises an actual strain or a numerical quantity related to strain, e.g. it may comprise a numerical quantity that is a mathematical function of the actual strain, such that it may vary proportionally with the strain.

As used herein the term “substrate layer” may refer to a layer of the web that has the primary load carrying function. It may be formed of a polymer/plastic-based material, e.g. Medium-density polyethylene (MDPE), polypropylene (OPP) or polyethylene terephthalate (PET). It may be formed of a paper-based material. The substrate layer may have a thickness of 10 - 30 x 10^-6 m (i.e. 10 - 30 micron).

As used herein the term “barrier layer” may refer to a layer of the web that provides an oxygen and/or moisture and/or light barrier to a material that can be contained in packaging formed by the web. The barrier layer may be formed of a metal-based material, e.g. Aluminium, Nickel or Chromium, oxides of the aforesaid. The barrier layer may be formed of other non-metal materials, e.g. silicon dioxide based. The barrier layer may have a thickness of about 10 x 10^-9 m (i.e. 10 nm).

As used herein the term “coating layer” may refer to an arrangement that coats the barrier layer (and/or in other examples the substrate layer), either directly or via an intermediate layer. The coating layer may be formed of an ink, a lacquer or be plastic-based. Examples include Polyvinyl alcohol (PVOH). The coating layer may have a thickness of about 2 x 10^-6 m (i.e. 2 micron), which may be ± 10% or 20%.

As used herein the term “laminate layer” may refer to an arranged that provides a protective layer over the coating layer. Examples include Polyvinyl alcohol (PVOH)

As used herein the term “method of upgrading” may refer to a process where an existing system that presently forms the web is upgraded to include strain parameter determination related to a strain of the web.

As used herein the term “record” may refer to an electronic (e.g. stored on computer readable medium) or a physical record (e.g. printed/graphical), which comprises a relationship between cross sectional positions of the web and the determined strain parameter.

As used herein, the term "electrical circuitry" or "circuitry" or "control electrical circuitry" may refer to one or more hardware and/or software components, examples of which may include: one or more of an Application Specific Integrated Circuit (ASIC) or other programable logic; electronic/electrical componentry (which may include combinations of transistors, resistors, capacitors, inductors etc); one or more processors (e.g. circuitry structure of the processor); a non-transitory memory (e.g. implemented by one or more memory devices), that may store one or more software or firmware programs; a combinational logic circuit; interconnection of the aforesaid. The electrical circuitry may be located entirely at one component of the system, or distributed between a plurality of components of the system (e.g. a server system and/or external device) which are in communication with each other over a computer network via communication resources.

As used herein, the term "processor" or "processing resource" may refer to one or more units for processing, examples of which include an ASIC, microcontroller, FPGA, microprocessor, digital signal processor (DSP), state machine or other suitable component. A processor may be configured to execute a computer program, e.g. which may take the form of machine readable instructions, which may be stored on a non-transitory memory and/or programmable logic. The processor may have various arrangements corresponding to those discussed for the circuitry, e.g. on-board or distributed as part of the system. As used herein, any machine executable instructions, or computer readable media, may be configured to cause a disclosed method to be carried out, e.g. by the system or components thereof as disclosed herein, and may therefore be used synonymously with the term method, or each other. As used herein, the term "computer readable medium/media" or "data storage" may include any medium capable of storing a computer program or data, and may take the form of any conventional non-transitory memory, for example one or more of: random access memory (RAM); a CD; a hard drive; a solid state drive; a memory card; a DVD. The memory may have various arrangements corresponding to those discussed for the circuitry.

As used herein, the term "communication resources" or "communication interface" may refer to hardware and/or firmware for electronic information transfer. The communication resources/interface may be configured for wired communication (“wired communication resources/interface”) or wireless communication (“wireless communication resources/interface”). Wireless communication resources may include hardware to transmit and receive signals by radio and may include various protocol implementations e.g. the 802.11 standard described in the Institute of Electronics Engineers (IEEE) and Bluetooth™ from the Bluetooth Special Interest Group of Kirkland Wash. Wired communication resources may include; Universal Serial Bus (USB); High-Definition Multimedia Interface (HDMI) or other protocol implementations. The web system may include communication resources for wired or wireless communication with an external device and/or server system.

As used herein, the term "network" or "computer network" may refer to a system for electronic information transfer between a plurality of apparatuses/devices. The network may, for example, include one or more networks of any type, which may include: a Public Land Mobile Network (PLMN); a telephone network (e.g. a Public Switched Telephone Network (PSTN) and/or a wireless network); a local area network (LAN); a metropolitan area network (MAN); a wide area network (WAN); an Internet Protocol Multimedia Subsystem (IMS) network; a private network; the Internet; an intranet; personal area networks (PANs), including with Bluetooth a short-range wireless technology standard.

As used herein, the term “external device” or "external electronic device" or “peripheral device” may include electronic components external to the converting machine, e.g. arranged at a same location or remote therefrom, which communicate therewith over a computer network. The external device may comprise a communication interface for communication with the machine and/or a server system. The external device may comprise devices including: a smartphone; a PDA; a video game controller; a tablet; a laptop; or other like device.

As used herein, the term “server system” may refer to electronic components external to converting machine, e.g. arranged at a same location or remote therefrom, which communicate therewith over a computer network. The server system may comprise a communication interface for communication with the converting machine or the external device. The server system can include: a networked-based computer (e.g. a remote server); a cloud-based computer; any other server system.

[General system description]

Referring to figure 1 , a system 2 for continuous formation of a web 4 of material comprises process stations 6; a transmission system 8 for handing of the web 4 between the process stations 6, and; electrical circuitry 10. The system 2 implements a formation process under the control of the electrical circuitry 10 to form and/or process the web 4, as will be discussed. The electrical circuitry 10 is arranged at the process stations 8.

In variant embodiments, which are not illustrated the electrical circuitry may be distributed over one or more components of the system, including an external device and/or server system.

Referring to Figure 2, the web 4 comprises a barrier layer 12 and a coating layer 14, and is supplied to the system 2 as a roll 16 of said layers. During the formation process, a coating layer 18 and laminated layer 20 are added to the web 4, as will be discussed. A completed formation process provides a roll 22 of said layers. Hence the web 4 as used herein may refer to the barrier layer 12 and a coating layer 14 and optionally the coating layer 18 and optionally the laminated layer 20.

In variant embodiments, which are not illustrated, the rolls may be omitted, e.g. the web is supplied or extracted in sheet form; although the coating layer is illustrated as coating the barrier layer, it may alternatively coat the substrate layer; although the laminated layer is illustrated as laminating the coating layer, it may alternatively laminate another layer, e.g. the barrier or substrate layer.

Referring to Figure 2, the process stations 6 are implemented in order of processing as: an unwinder station 30 (for unwinding of the roll 16); a coating station 32 (for application of the coating layer 18 to the web 4); a drying station 34 (for drying of the coating layer 18 on the web 4); a laminating station 36 (for application of the laminated layer 20 to the web 4); an unwinder station 38 for the laminating layer 18, and; a rewinder station 40 (for winding of the roll 22).

In variant embodiments, which are not illustrated, alternative stations and station orders may be implemented. For example: the unwinder/rewinder stations may be omitted in embodiments where the web is supplied or extracted in sheet form; the laminator station may be omitted; the drying station may be omitted; the coating station may be omitted, e.g. the system is alternatively configured for formation of be barrier layer in association with the substrate layer (including by a vapour deposition process).

The transmission system 8 comprises a plurality of rollers 50 for rotary engagement of said web 4. The Transmission systems of the state-of-the-art are configured to control the tension of the web, which is required for coating or laminating the web according to specifications. This is commonly performed by running the rollers 54,56 that are located downstream slightly faster than the rollers located upstream 52,54. The control of the rotation of said roller is based on a load cell or a dancer roller. The load cell 72 measures the load from which the tension can be computed. The dancer roller 70, by construction, ensures a constant tension of the web.

The transmission systems, as described above, are optimized for maintaining the mechanical properties of the substrate 14 during the coating or laminating process. In the system according to the invention, the substrate layer 14 has a lower Young’s modulus than the barrier layer 12. The Young’s modulus typically differs by one or two orders of magnitude. Consequently, the barrier layer 12 is stiffer and is therefore much more likely to form defects (e.g. cracks), than the substrate layer 14 as the strain of the web 4 is increased. Said defects could compromise the integrity of any packaging (not illustrated) formed from the web 4.

Thus, to assess the integrity of the barrier layer 12 an electrical circuitry 10 is arranged to determine a strain parameter related to a strain of said web 4 (e.g. or either web of the barrier later and substrate layer and/or the web of the barrier layer, substrate layer and the coating layer and optionally the laminated layer) based on a rotation of one or more of the rollers 50, as will be discussed. In an embodiment, the electrical circuitry 10 acts as an observer of the regulation process, which regulates the tension for coating the web.

[Transmission system]

Referring to figure 2, the rollers 50 of the transmission system 8 can have various configurations:

1) The rollers 50 can be motorised, which comprises driven to rotate by a drive system (not illustrated). The drive system may implement independent control (e.g. so that the rotation of the roller can rotate independently of any other roller) of the rotation of the roller. The drive system may for example comprise a motor (e.g. an electrical or hydraulically operated motor) and optionally a gear system to rotationally couple the motor to the roller. The drive system may also drive the roller to rotate at a constant angular velocity.

2) The rollers 50 can be non-motorised (not illustrated), which comprises freely rotating, that is, they are not driven to rotate by a drive system and are driven to rotate by engagement with the moving web 4.

3) Each roller 50 may be implemented as a single roller.

4) Each roller 50 may be implemented as a pair of rollers, e.g. with a diametrically opposed rollers about the web 4, which counter rotate.

In the illustrated example of figure 2, positions of the rollers 50 include:

A) a first roller 52 arranged between the unwinder station 30 and the coating station 32;

B) second roller 54 arranged at the coating station 32 and hence before the drying station 34, and;

C) third roller 56 arranged at the laminating station 36, hence subsequent to the drying station 34.

The first roller 52, the second roller 54, and the third roller 56 are motorised rollers and comprise a pair of counter rotating rollers, hence configurations 1) and 4) above.

In variant embodiments, which are not illustrated: other roller configurations may be implemented for the first to third rollers, e.g. configurations 2) and 3), and; other rollers may be arranged at other positions in the transmission system.

The transmission system 8 is arranged with first to fourth tension control configurations 60, 62, 64, 66, for control of a tension in the web 4 (the tension in the direction of elongation of the web 4) at various locations:

1) The first tension control configuration 60 is for control of the tension in the web 4 between the unwinder station 30 and the first roller 52. Hence for control of the tension in the web 4 following unwinding. The first tension control configuration 60 comprises a dancer roller 70 arranged between the unwinder station 30 and the first roller 52. The dancer roller 70 may comprise an idler roller mounted on a swivelling arm (not illustrated), with the idler roller pressed into the web 4 path with a defined pressure to regulate tension. The tension in the web 4 between the unwinder station 30 and the first roller 52 can be controlled by varying the speed of the roll 16 of the unwinder station 30 relative to the first roller 52.

In variant embodiments, which are not illustrated: a tension in the web is controlled by varying the speed of the first roller via a control system (examples of which are provided below) based on the position of the dancer roller. In this case, the rotation of the rollers must be controlled to ensure that the dancer roller stays within its operating range, i.e. between two positions. If the dancer roller goes past the said positions, it loses its ability to maintain the web tension. Thus, the relative speed of the downstream rollers 54,56 with respect to the upstream roller 52,54 is controlled to maintain the dancer roller within its operating bounds. (In this example, roller 54 acts as a downstream roller along the web patch from roller 52 to 54 and as an upstream roller for the path going from roller 54 to 56.)

2) The second tension control configuration 62 is for control of the tension in the web 4 between the first roller 52 and second roller 54 (hence for control of tension subsequent to unwinding and subsequent to/during coating). The second tension control configuration 62 comprises a load cell 72 arranged between said rollers 52, 54. An example of a suitable load cell 62 comprises a Montalvo ES-Series load cell, which is coupled to a dedicated roller.

The tension is controlled by varying the speed of the first roller 52 with respect to the second roller 54. The control is performed by varying the speed of the upstream first roller 52 using a feedback loop with the load cell 72, in which the load cell provides a load, that is related to tension of the web 4 as an input.

The speed of the first roller 52 is controlled by a feedback loop, which implements a control system with an input as a target tension in the web 4 and an output as rotational control of the first roller 52. The control system implements proportional integral and optionally differential control (PID), via a processing unit executing machine readable instructions.

In variant embodiments, which are not illustrated: the tension is controlled by varying the speed of the first roller and/or the second roller; other control systems can be implemented e.g. proportional integral (PI); the control system is implemented by hardware, e.g. capacitors and indictors etc or is implemented as gated logic, e.g. as an ASIC, or other implementation.

The rotation of a roller may be measured directly at the roller or indirectly via a rotationally connected member (e.g. a driver of a drive system or part of the drive system). Rotation may be measured by a rotary encoder, a DC stepped motor (with integrated rotary position determination) or other suitable system.

3) The third tension control configuration 64 is for control of the tension in the web 4 between the second roller 54 and third roller 56 (hence for control of tension during/subsequent to coating and during drying). The third tension control configuration 64 comprises a load cell 74 arranged between said rollers 54, 56. The configuration is as described for the second tension control configuration 62, including the associated variants, which for brevity is not reiterated. However since in the second tension control configuration 62 the tension is controlled by varying the speed of the second roller 54 for the third tension control configuration 64, the tension is controlled by varying the speed of the second roller 54 with respect to the speed of the third roller 56.

4) The fourth tension control configuration 66 is for control of the tension in the web 4 between the third roller 56 and the rewinder station 40. Hence for control of the tension in the web 4 during rewinding. The fourth tension control configuration 66 comprises a dancer roller 76 arranged between the rewinder station 40 and the third roller 56. The configuration is as described for the first tension control configuration 60, including the associated variants, which for brevity is not reiterated.

In variant embodiments, which are not illustrated: other tension control configurations may be implemented, for example: additional dancer rollers.

[Location of strain determination in system]

It will be appreciated that the strain parameter may be determined with the embodiment method between any two rollers 50 (or at a roller 50) of the transmission system 8. However, it may be preferable to implement between two adjoining rollers 50.

Referring to figure 2, the coating station 54 may implement the coating layer 18 by vapour deposition or bonding (e.g. for a pre-existing coating layer) or by other suitable means. Consequently, strain in the web 4 may be introduced by the thermal contraction or extension of the web 4 caused by coating.

The drying station 34 is positioned downstream (in respect of a transmission direction of the web 4 relative to the transmission system 8) of the coating station 32 such that the drying station 34 dries the coating layer 20 on the web 4. Drying may be implemented by convective heat transfer from heated air and/or radiant heat transfer or other suitable means Consequently, strain in the web 4 may be introduced by the thermal extension of the web 4 caused by drying as it is heated.

It is therefore desirable to implement strain measurement of the web 4 during or subsequent to drying and/or coating. Hence in the illustrated example, the strain parameter may be determined for any two of the: first roller 52; second roller 54, and; third roller 56, as will be discussed. Moreover, the tension on the first tension control configuration 60 and the fourth first tension control configuration 66 are required to be controlled.

[Example calculation process for strain parameter]

In a first example, the electrical circuitry 10 is configured to determine the strain parameter based on a time-based integral of a difference in rotation between two of the rollers. For example, a by subtracting the total rotation of one roller from another over a period of time.

Where the rotation of one or both rollers are controlled by the previously discussed load cell/dancer roller with a PI D or PI control loop, the integral component can be used as the control value. Specifically, if a norm (e.g. an absolute) of said value is above threshold, the strain is considered as out of specification.

Said threshold can be computed in a calibration phase. The calibration phase may consist of performing tests where the strain for the web is increased and until the resulting substrate (measured in a laboratory), has a barrier property that is unacceptable. The threshold can be set as the absolute value of the integral component used when the strain parameter still produces an acceptable substrate.

In a second example, the electrical circuitry 10 is configured to determine the strain parameter using a single roller. For example, the single roller may experience a sudden change an angular velocity e.g. due to a change in rotation caused by the described control system. The change in angular velocity (e.g. the angular acceleration) may be used as the strain parameter.

[Usage of strain parameter]

The electrical circuitry 10 may be configured to determine, based on the strain parameter, if a strain threshold has been crossed. The threshold determination may be implemented to identify when the strain has crossed an acceptable amount. This step can be implemented by comparing (e.g. with a comparator) the calculated strain parameter to a threshold value to see if it has been crossed. The threshold value for the strain can be selected based on the type of barrier layer 12 and substrate layer 14 (including their thickness) present in the web 4, and may be selected based on empirical data, e.g. for prior comparable webs for threshold strains for which a defect in the barrier layer occurred at.

In response to the determination of a threshold being crossed, the electrical circuity 10 may implement one or more of the following actions:

1) the electrical circuitry 10 is configured to provide a notification to a user interface (not illustrated). For example, the user interface may comprise one of more of the following: visual feedback; audible feedback; haptic feedback. The user interface may be provided by a peripheral device as defined herein.

2) the electrical circuitry 10 is configured to implement storage of an entry in a database associated with a particular web. For example, an electronic record may be formed that relates the strain parameter to a particular cross-section of the web (as discussed in more detail below) In this way, a record of the points of the web where the strain has been exceeded may be derived.

3) the electrical circuitry 10 is configured to implement halting of web formation. For example, halting may comprise one or more of the following: halting of an operation of a process station (e.g. coating or drying); halting of the transmission system. In this way, the strain of the relevant section may be inspected and/or the web may be replaced.

4) the electrical circuitry is configured to determine an adverse condition of the system associated with the crossing of the threshold. The adverse condition may comprise a setting of the system that causes too high a strain in the web. Examples of which include: excessively high drying temperature from the drying station; too great an acceleration applied to a roller; incorrect process parameters, and; other relevant settings.

[Record of strain parameter]

As discussed for action 2) above, the electrical circuitry 10 may associate the strain parameter with one or more cross-section portions of the web 4. That is, the strain is assumed as one value across a transverse section, and a section length (in a transmission direction of the 4 relative the transmission system 8) between two rollers (between which the strain is measured) is assumed to have one strain value. The strain parameter and associated web position may be stored as a record, which may be an electronic record (e.g. a database, including as a key value database paradigm/array) and/or a physical record (e.g. as printed material). In this way, a record of the quality at points of the web may be provided, which may be used for example, to excise portions of the web where an acceptable strain has been exceeded, and/or to provide a quality rating of the roll/web. The strain parameter may be associated with each cross- sectional position (e.g. at suitable discrete increments) or just for points where the strain threshold has been crossed (as discussed previously). A roll ID for identification of the roll may also be stored as part of the record.

[Method of formation]

A method of determining a strain of a web may comprise the following steps:

Step 1 : a rotation of two rollers 50 is determined;

Step 2: determining a strain parameter related to a strain of the web 4 based on the determined rotation from step 1 .

Step 3: determining if a strain threshold has been crossed, and if crossed implementing one or more of the aforedescribed actions.

Step 4: the strain parameter is associated with one or more cross-section portions of the web 4, and;

Step 5: discarding a portion of the web (or the entire web) for which the strain parameter has crossed the threshold, i.e. where damage to the barrier layer occurred.

The method may be implemented as part of a method of forming a web 4 comprising forming a coating layer 18 on a web of a barrier layer 12 and a substrate layer 14. Said method comprising forming with the coating station 32 the coating layer 18 on the web 4.

Variants of the above method are to be completed, including those that may introduced by the various embodiments disclosed herein. For example: steps 3 - 5 may be omitted; other calculation methods for the strain parameter may be implemented e.g. based on a rotation of a single roller; the strain parameter may be determined for a system that associates the barrier layer with substrate or other suitable system.

It will be appreciated that any of the disclosed methods (or corresponding apparatuses, programs, data carriers, etc.) may be carried out by either a host or client, depending on the specific implementation (i.e. the disclosed methods/apparatuses are a form of communication(s), and as such, may be carried out from either ‘point of view’, i.e. in corresponding to each other fashion). Furthermore, it will be understood that the terms “receiving” and “transmitting” encompass “inputting” and “outputting” and are not limited to an RF context of transmitting and receiving radio waves. Therefore, for example, a chip or other device or component for realizing embodiments could generate data for output to another chip, device or component, or have as an input data from another chip, device or component, and such an output or input could be referred to as “transmit” and “receive” including gerund forms, that is, “transmitting” and “receiving”, as well as such “transmitting” and “receiving” within an RF context.

As used in this specification, any formulation used of the style “at least one of A, B or C”, and the formulation “at least one of A, B and C” use a disjunctive “or” and a disjunctive “and” such that those formulations comprise any and all joint and several permutations of A, B, C, that is, A alone, B alone, C alone, A and B in any order, A and C in any order, B and C in any order and A, B, C in any order. There may be more or less than three features used in such formulations.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the terms “a” or “an,” as used herein, are defined as one or more than one. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an." The same holds true for the use of definite articles. Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Unless otherwise explicitly stated as incompatible, or the physics or otherwise of the embodiments, example or claims prevent such a combination, the features of the foregoing embodiments and examples, and of the following claims may be integrated together in any suitable arrangement, especially ones where there is a beneficial effect in doing so. This is not limited to only any specified benefit, and instead may arise from an “ex post facto” benefit. This is to say that the combination of features is not limited by the described forms, particularly the form (e.g. numbering) of the example(s), embodiment(s), or dependency of the claim(s). Moreover, this also applies to the phrase “in one embodiment”, “according to an embodiment” and the like, which are merely a stylistic form of wording and are not to be construed as limiting the following features to a separate embodiment to all other instances of the same or similar wording. This is to say, a reference to ‘an’, ‘one’ or ‘some’ embodiment(s) may be a reference to any one or more, and/or all embodiments, or combination(s) thereof, disclosed. Also, similarly, the reference to “the” embodiment may not be limited to the immediately preceding embodiment.

As used herein, any machine executable instructions, or compute readable media, may carry out a disclosed method, and may therefore be used synonymously with the term method, or each other.

The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various implementations of the present disclosure.

LIST OF REFERENCES

2 System

4 Web

12 Barrier layer

14 Substrate layer

16 Roll (barrier layer and substrate layer)

18 Coating layer

20 Laminated layer

22 Roll (barrier layer, substrate layer, coating layer, laminated layer)

24 Roll (laminated layer)

6 Process stations

30 Unwinder station

32 Coating station

34 Drying station

36 Laminating station

38 Unwinder station (laminating layer)

40 Rewinding station

8 Transmission system

50 Rollers

52 First roller

54 Second roller

56 Third roller

60 First tension control configuration

70 Dancer roller

62 Second tension control configuration 72 Load cell

64 Third tension control configuration

74 Load cell

66 Fourth tension control configuration 76 Dancer roller Electrical circuitry

Claims

1 . A system for continuous formation of a web of material comprising a coating layer, a barrier layer (12) and substrate layer (14), the system comprising: a coating station (32) for associating a coating layer (18) with a web of the barrier layer (14) and substrate layer (12); a transmission system (8) arranged for transmission of the web (4) relative to the coating station (32), the transmission system comprising a plurality of rollers (50) for rotary engagement with said web (4), an electrical circuitry (10) configured to control the roller rotation and the web tension for ensuring that the coating layer (18) is formed according to specification, wherein the barrier layer (12) has a young modulus larger than the young modulus of the substrate layer (14), characterized in that an electrical circuitry is arranged to determine a strain parameter related to the strain of said web (4) derived from a differential rotation of a plurality of the rollers (50) and wherein the electrical circuitry is arranged to assess the integrity of the barrier layer (12) from the value of said strain parameter.

2. The system of claim 1 , wherein the electrical circuitry implements proportional and integral (PI) control of the roller (50) rotation wherein the strain parameter is determined based on the integral component of the PI control.

3. The system according to any preceding claim, wherein the barrier layer (12) has a young modulus at least 10 times larger than the young modulus of the substrate layer (14).

4. The system according to any preceding claim, wherein the assessment of the integrity of the barrier layer (12) is performed by comparing the strain parameter to a predetermined threshold.

5. The system according to any preceding claim, wherein in response to said threshold being crossed, the electrical circuitry is configured to implement one or more of: a notification to a user interface; storage of an entry in a database associated with a particular web; halting of web formation and; determine an adverse condition of the system associated with the crossing of the threshold.

6. The system of any preceding claim, wherein the electrical circuitry is configured to: associate the strain parameter with one or more cross-sectional portions of the web (4).

7. The system of any preceding claim, wherein the coating station (32) is configured to apply the coating layer (18) to the web (4) wherein the barrier layer (12) is a metal-based barrier layer and wherein the substrate layer (14) is a plastic-based substrate layer.

8. The system of any preceding claim, wherein the control of the roller rotation is based on the value of a load cell (72) arranged to determine the tension of the web (4), and/or on the position of a dancer roller (70) arranged to control the tension of the web,

9. The system of any preceding claim, wherein the at least one of the rollers (50) is driven to rotate by a drive system to implement independent control of the rotation of the roller (50).

10. The system of any preceding claim comprising: a drying station (34) arranged downstream of the coating station (32), and the strain parameter determined for a portion of the web (4) during and/or after the coating station (32), including before or during drying from the drying station (34).

11. A method of assessing the integrity of the barrier layer (12) of a web (4) comprising a substrate layer (14) and a barrier layer (12), the method comprising: determining a difference in rotation of a plurality of rollers (50), which are implemented to handle said web (4), and; determining a strain parameter related to a strain of the web (4) based on the determined difference in rotation of a plurality of the rollers (50), and comparing the strain parameter to a predetermined threshold for assessing said integrity.

12. The method of claim 11 wherein the predetermined threshold depends on the ratio between the young modulus of the barrier layer (12) and the young modulus of the substrate layer (14).

13. A method of forming a web (4) comprising associating a coating layer (18) with a web (4) of a barrier layer (12) and a substrate layer (14), the method comprising: forming, with a coating station (32), the coating layer (18) and associating with the web (4) of the barrier layer (12) and the substrate layer (14), and; assessing the integrity of the barrier layer (12) according to the method of claim 11.

14. The method of claim 13 comprising: associating the strain parameter with one or more cross-section portions of the web (4) , and; discarding a portion of the web (4) for which the strain parameter has crossed the predetermined threshold.

15. Electrical circuitry (10) or a computer program comprising program code executable on one or more processors, to implement the method of claim 11 .