Patent Description:
Fabrication of thin conductive elements on various types of carriers has been under keen interest and much progress has been made in the field. For example, a significant number of solutions for electronic article surveillance and radio-frequency identification purposes have been developed and described in patent literature. Typically, in these solutions, an antenna is fabricated by cutting through a laminate formed of a metal foil and a reinforcing underlay and a reinforced sheet carrying the antenna is then adhesively attached on a receiving carrier. This is naturally a practical approach when the effect on mechanical properties of the receiving carrier or to the thickness of the receiving carrier by the transferred element are not important.

However, there are many applications where the receiving carrier needs to be elastic and/or stretchable so that it can be, for example, comfortably worn. In some applications the receiving carrier needs to have a web-like form so that it can be roll-to-roll processed but is also elastically deformable so that it appropriately follows contours and deformations of a curved surface on which it is to be subsequently fixed. In these type of applications, additional reinforcing and/or carrier layers between the conductive element and the receiving carrier are simply not acceptable. For example, when a patterned element formed of a layer of conductive metal and a layer of reinforcing paper material is placed on a fabric, the fabric no longer bends in a way it should in order to be comfortably worn. This is especially the case if the surface covered by the conductive element is large like, for example, in applications where the conductive element is designed to deliver heat through a fabric web. On the other hand, it is considered practically not possible to make a patterned metal element robust enough to endure transfer onto the receiving carrier without the reinforcing underlay and at the same time to adequately maintain the elastic properties of the receiving carrier when attached to it.

Deformability of the receiving carrier is not the only characteristic that is compromised by an intermediate layer under the conductive element. In a broad range of applications, thickness or coverage of the element placed on the receiving carrier is of importance and use of additional reinforcing sheets to transfer the conductive element on such receiving carrier web is problematic or even impossible. This is the case with, for example, functional conductive elements laminated on or between layers of kraft paper. The conductive element introduced into the laminate needs to be as thin as possible to avoid adverse effect to the appearance and functionality of the laminate.

On the other hand, in some applications electronic devices are integrated with materials that provide overall structural strength of a laminate body. In such applications, maintaining this structural integrity of the body is very important. In a body that includes structural materials such as fiber enforced composites, a conductive element for an electronic functionality could be placed between reinforcing fiber layers. An additional carrier or reinforcing layer for the electronic functionality would create additional material boundaries within the body and prevent the composite polymer to form physical and/or chemical bonds continuously through the carrier or reinforcing layer. The structural integrity of the body would thus be very negatively affected.

Another conventional approach to attach a conductive element on a receiving carrier has been to pattern the conductive element directly onto it. In these applications, pervasive methods like laser cutting, die-cutting or even kiss-cutting are out of the question, because the risk of damaging the underlying receiving carrier is too high. Printing methods, like inkjet printing, offset printing, screen printing, flexography and gravure printing have been used in applications where the conductive element is thin, and the receiving carrier is not a deformable and/or porous web. However, they are not well suitable for depositing a conductive element to a web of fibres. For example, the porous surface of such web absorbs printed material unevenly, so the printed form of the conductive element is typically not accurate enough.

<CIT> discloses a roll-to-roll processing method for manufacturing an integrated back-sheet for a back contact photovoltaic module with a metal foil circuit adhered to a polymer substrate.

An object of the present disclosure is to provide a solution that solves or at least alleviates the above challenges in providing conductive elements on many types of carrier webs.

The object of the invention is achieved by a method as stated in independent claim <NUM>. Some embodiments of the invention are disclosed in the dependent claims.

The disclosed embodiments are based on the idea of operating systematically with two different types of adhesives in selected stages of the roll-to-roll processing. An advantage of the proposed solutions is that a very thin element of conductive material can be accurately and reliably transferred to adhesively attach on a carrier surface.

In the following, the disclosure will be described in greater detail by means of examples with reference to the accompanying drawings, in which.

Roll-to-roll processing is a fabrication method used for manufacturing products. In a roll-to-roll process a web of materials can be continuously fed from one reel onto another and at the same time materials can added to the progressing web or removed from it to produce a desired product.

<FIG> illustrates stages of an example of a roll-to-roll processing method applying the claimed invention. It is to be noted that the drawings included in this specification are schematic figures, which show only structural elements that are necessary to explain the non-restrictive examples of the claimed method. It is clear that implementations of the roll-to-roll processing method may include several additional stages and conventional parts that are well known to a person skilled in the art and will thus not be discussed in detail herein.

The roll-to-roll processing method disclosed in this text includes patterning boundaries of one or more conductive elements into a layered web that includes a conducting layer and a first substrate layer bound to each other with a first adhesive. Boundaries of one or more conductive elements are patterned so that said patterning includes cutting the boundaries through the conducting layer but not through the first substrate layer. Parts of the conducting layer outside the boundaries of the one or more conductive elements are removed from the first substrate layer and top surfaces of the one or more conductive elements to a second substrate layer with a second adhesive. In the end, a resulting layered web that includes at least the second substrate and the conductive elements is rolled on a reel.

In the example of <FIG>, the first substrate layer is a sacrificial substrate layer and the first adhesive is a releasably binding adhesive. The second substrate is a first carrier layer and the second adhesive is a carrier binding adhesive. The term layer refers in this text to an elongate web of material that can be rolled around a reel for a roll-to-roll process. Accordingly, a conducting layer refers here to an elastic elongate sheet with a tensile strength that enables it to be roll-to-roll processed as a continuous web but is thin and thus flexible enough to not have substantial effect on mechanical properties of an underlying surface when attached to it. The conducting layer may be made of a material (e.g. metal) that provides both the required conductivity and the required tensile strength, but for the required conductivity, the conducting layer typically includes a very thin layer of conductive material on a thin polymer web.

The conductive material may be metal or some metal composition including conductive metals. Examples of such conductive metals include aluminum, copper, silver, platinum, palladium, zinc, nickel, gold, chromium, iron, molybdenum and equals and their alloys. Also conductive allotropes of carbon, or some semiconductor materials, like silicon, germanium, gallium arsenide, can be used as the conductive material, specifically when doped for higher conductivity.

The polymer web may include plastics based on polymers, their copolymers and mixtures, for example, poly(ethylene terphtalate), poly(naphtalene), poly(methyl methacrylate), poly(imide), poly(ethylene), cyclo-olephinic polymers and -co-polymers, thermoplastic urethane, poly(carbonate), poly(propylene), poly(vinyl chloride), poly(tetra fluoro ethane) and similar, silicones, or the like. In order to appropriately conform to the deformations of the receiving carrier, the thickness of the layer of conductive material is of the order of <NUM> to <NUM> micrometers and the thickness of the polymer film is of the order of <NUM> to <NUM> micrometers. In some examples, the layer of conductive material is of the order of <NUM> to <NUM> micrometers and the thickness of the polymer film is of the order of <NUM> to <NUM> micrometers. In some other layer structures, the layer of conductive material is of the order of <NUM> to <NUM> micrometers and the thickness of the polymer film is of the order of <NUM> to <NUM> micrometers. Very successful applications have been made with, for example, a conducting layer that contains a <NUM> micrometer layer of aluminum on a <NUM> micrometer layer of polyethylene terephthalate (PET), but the manufacturing process described herein enables application of even thinner conducting layers. With thicknesses in this range, the polymer film provides at least <NUM> % of the tensile strength of the conducting layer. As noted above, unlike a reinforcing paper layer, this type of polymer film can be provided with a thickness that provides a necessary tensile strength for transferring the conducting layer laminate as such from reel to reel and also to appropriately endure the force required to release the adhesion of the releasably binding adhesive. Even so, the conducting layer is still thin and flexible enough to not notably compromise web-like mechanical properties, like flexibility, of the receiving carrier when finally fixed on it. It has been detected that to be durable enough for efficient processing, paper materials need to be so thick that their existence on a flexible receiving carrier significantly stiffens the web-like form, and thus makes the resulting receiving carrier unsuitable for purposes where elastic conformity is required. Furthermore, use of reinforcing sheet of paper tends to be problematic for applications, where added thickness by the conductive element needs to be minimized.

The sacrificial substrate layer refers here to a reinforcing layer on which the conducting layer remains releasably bonded through patterning and material releasing stages that will be described in detail later in this text. Advantageously the sacrificial substrate layer is the reinforcing element that provides more than <NUM>% of the tensile strength of the layered web and is therefore considerably (at least two times) thicker than the conducting layer. Examples of applicable materials for the sacrificial substrate layer include plastics based on polymers, their copolymers and mixtures, for example, poly(ethylene terphtalate), poly(naphtalene), poly(methyl methacrylate), poly(imide), poly(ethylene), cyclo-olephinic polymers and o-polymers, thermoplastic urethane, poly(carbonate), poly(propylene), poly(vinyl chloride), poly(tetra fluoro ethane) and similar, silicones, or the like. Very successful implementations have already been made with, for example, a sacrificial substrate layer of <NUM> millimeter polyester film. The sacrificial substrate layer may also include some other reinforcing material, like a paper sheet that is covered with a thin layer of plastic materials, like the ones listed above.

The sacrificial substrate layer and the conducting layer are laminated into a temporary composite structure by gluing their surfaces to each other with a releasably binding adhesive. Releasably binding adhesive in this context refers to any adhesive that binds the sacrificial substrate layer and the conducting layer to each other so that they remain fastened while boundaries of a conductive element are pattered into the conducting layer, but so that the adhesion of the releasably binding adhesive can be released by pulling the surfaces of the sacrificial substrate layer and the conducting layer away from each other with a force that does not break either of the layers. Examples of releasably binding adhesives include silicones, acrylates, epoxides, urethanes, or poly(vinyls) that can be deposited on the sacrificial substrate layer by lamination, spraying, coating, printing or as a hotmelt glue.

In the example of <FIG>, the conducting layer <NUM> is rolled out of one reel <NUM> and the sacrificial substrate layer <NUM> is rolled out of another reel <NUM> and the layers are pressed on each other with nip rolls <NUM>. Alternatively, the layers <NUM>, <NUM> can be laminated to each other in beforehand, and fed to the roll-to-roll process in a readily laminated form. In the example of <FIG>, the sacrificial substrate layer <NUM> is covered by a layer of the releasably binding adhesive. In this example, the roll-to-roll process is shown to include a spray station <NUM> in which the releasably binding adhesive is spread on the sacrificial substrate layer after it is rolled out the reel <NUM>. However, the mechanism for providing the releasably binding adhesive is not relevant, as such. Examples of other applicable deposition methods include flexography, gravure, wire printing, off-set printing, screen printing, slot-die and reverse-gravure, among others. The sacrificial substrate layer may even be provided as readily covered with releasably binding adhesive and a protective sheet that is reeled off before the sacrificial substrate layer is fed into the process. The essential aspect is that the releasably binding adhesive is provided between a surface of the conducting layer <NUM> and a surface of the sacrificial substrate layer <NUM> so that when the surfaces are put into contact, the releasable adhesion activates or can be activated to releasably bind the surfaces to each other. Accordingly, the releasably binding adhesive can alternatively be deposited on a surface of the conducting layer. Activation of the releasably binding adhesive refers here to any function that completes the binding effect of the releasably binding adhesive. Examples of applicable activation methods to bond an adhesive with the adherent include, for example, application of pressure, enabling contact, cooling, heating, radiation, to mention some.

Even if the adhesion is to be released, the strength of the adhesion of the releasably binding adhesive needs to be strong enough to support the very thin conducting layer during the cutting operation so that the boundaries of the resulting pattern are accurate. Advantageously, the layer of conductive material provides the surface of the conducting layer that is put against the surface of the sacrificial substrate layer. The polymer film becomes then positioned to the side in which the patterning cuts through the conducting layer. This provides a protecting effect that ensures that the resulting pattern, which is cut from the layer of conductive materials, is more accurately in the designed form.

<FIG> illustrates the patterning stage with a cutting tool <NUM>. A cutting tool that patterns a layered web by means of force typically includes a die that shears the layered web to a predefined depth. Here the patterning is configured to cut the boundaries of conductive elements through the conducting layer but not through the sacrificial substrate layer. This kind of cutting method is known in the field as kiss-cutting. The die of a kiss-cutting tool may be, for example, a rotary flexible die or a solid die. However, alternative kiss-cutting mechanisms may be applied within the scope. For example, a beam of a high-power laser can be directed on the layered web for the purpose of laser-cutting through the conducting layer but not through the sacrificial substrate layer.

<FIG> provides a simplified illustration of a cutting tool <NUM>, an example of which is discussed in more detail with <FIG> shows an exploded view to layers of the roll-to-roll processed web and exemplary parts of the cutting tool. For a person skilled in the art it is clear that during operation, the shown elements are pressed against or adhesively attached to each other. The cutting tool may include a cutting reel <NUM> and an anvil reel <NUM>. The cutting reel <NUM> includes at least one cutting die, typically a matrix of dies that extend to a defined distance from the cutting reel <NUM>. During operation, the cutting reel is rotated and pressed against the anvil reel <NUM>. Between the rotating cutting reel <NUM> and the anvil reel <NUM> is a depth dimensioning mechanism that controls the distance between the rotating wheel <NUM> and the anvil reel <NUM>, and thus adjusts the cutting depth at a predefined level. A simple example of a depth dimensioning mechanism is a set of height-adjustable rigid sleeves that run in the edge of the anvil reel and during operation stop the cutting reel into abutment with their adjusted height. As can be seen both in <FIG>, the boundaries of the conductive elements form a continuous pattern so that after the patterning stage, the conductive elements are separated from the conducting layer as single elements and the parts of the conducting layer outside these boundaries form a continuous recessed web <NUM>.

Returning back to <FIG>, the recessed web <NUM> can be removed from the roll-to-roll processed web by releasing it from the sacrificial substrate layer and rolling it on a release reel <NUM> that is offset from the direction of progress of the roll-to-roll processed web. The parts of the conducting layer, which form the recessed web, become thus pulled away from the sacrificial substrate layer with a force that exceeds adhesion of the releasably binding adhesive. This is enabled by the tensile strength of the conducting layer, in this example, the tensile strength of the polymer film, and the appropriately weak adhesion of the releasably binding adhesive. It is noted that even if the adhesion is to be released, the adhesion needs to be strong enough to support the very thin conducting layer during the cutting operation so that accuracy of the boundaries of the resulting pattern is adequate. On the other hand, the releasably binding adhesive needs to be weak enough to enable release of the recessed web <NUM>.

After removal of the recessed web, the roll-to-roll processed web includes the sacrificial substrate layer and conductive elements attached on it with the releasably binding adhesive. In more detail, bottom surfaces of the conductive elements are bound to the sacrificial substrate layer with the releasably binding adhesive, and top surfaces of the conductive elements are exposed. These top surfaces can then be bound to a first carrier layer, which is now a receiving carrier, with a carrier binding adhesive. The example of <FIG> shows an exemplary embodiment wherein a film of the carrier binding adhesive is formed first on the first carrier layer <NUM>. This is illustrated by showing a spray station <NUM> in which the releasably binding adhesive is spread on the first carrier layer after it is rolled out the reel <NUM>. However, as discussed, in this example, the mechanism for providing the carrier binding adhesive is not relevant, as such. The essential aspect is that the carrier binding adhesive is provided between a surface of the first carrier layer <NUM> and top surfaces of the conductive elements so that when these surfaces are put into contact, the more permanent carrier binding adhesive can be activated to bind the surfaces to each other. The other essential aspect is that the two adhesives are selected or otherwise arranged so that adhesion between the conductive elements and the first carrier layer by the carrier binding adhesive is stronger than adhesion between the conductive elements and the sacrificial substrate layer by the releasably binding adhesive.

The first carrier layer <NUM> preferably includes a web of fibres on which at least one conductive element is to be attached. The web of fibres may be a woven web formed of a network of interlocked fibres or a non-woven web formed of fibres bonded together by chemical, mechanical, heat or solvent treatment. Said fibres can include natural or synthetic, for example, animal based fibres (e.g. hair, fur, skin, silk, etc.), plant-based fibres (e.g. pulpwood trees, cotton, straw, bamboo, etc.), mineral based fibres (e.g., basalt, glass, metal) or synthetic fibres (e.g. polyester, aramid, acrylic, nylon, carbon, etc.). As discussed above, forming conductive elements on such woven or non-woven webs of fibres has so far been considered very problematic, because there has not been a suitable method to transfer and fix a separate cut-out conductive element on the web of fibres without a stiff reinforcing underlay, which disrupts the elastic properties of the web of fibres. The method is naturally applicable for other types of webs, as well.

The term carrier binding adhesive refers in this context to any adhesive that does not harden in use and forms a strong adhesion between the first carrier layer <NUM> and the top surfaces of the conductive elements. Essentially, the adhesion by the carrier binding adhesive is stronger than the adhesion between the bottom surfaces of the conductive elements and the sacrificial substrate layer <NUM> formed with the releasably binding adhesive. Examples of the carrier binding adhesives include silicones, acrylates, epoxides, urethanes, poly(vinyls), to mention some. Accordingly, when the top surfaces of the conductive elements are put into contact with the layer of the carrier binding adhesive on the first carrier layer, adhesion of the carrier binding adhesive can be activated so that the conductive elements become firmly bonded to the surface of the first carrier layer <NUM>.

Now that the top surfaces of the conductive elements have been transferred and firmly glued on the first carrier layer without interfering mechanically stiffening elements, the sacrificial substrate layer can be removed from the one or more conductive elements. Due to the higher adhesive bond between the first carrier layer <NUM> and the top surfaces of the conductive elements than between the bottom surfaces of the conductive elements and the sacrificial substrate layer <NUM>, this can be implemented simply by pulling the sacrificial substrate layer <NUM> away from the one or more conductive elements with a reel <NUM> that is offset from the direction of the roll-to-roll processed web. This creates a force that exceeds adhesion of the releasably binding adhesive but not the adhesion of the carrier binding adhesive. The stronger adhesion of the carrier binding adhesive keeps the conductive elements secured on the first carrier layer <NUM> while the releasably binding adhesive lets the sacrificial substrate layer to be released from the bottom surfaces of the conductive elements.

After this stage, the roll-to-roll processed web includes only the conductive elements easily transferred and now firmly bound on the first carrier layer <NUM> without intermediate stiffening sheets, like reinforcing paper layers, that would adversely affect the elastic properties or structural integrity of the first carrier layer or increase the thickness of the resulting laminate. The resulting combination could already be used as a product that contains a receiving carrier and one or more conductive elements. However, <FIG> illustrates further optional stages that can be used to provide a laminate wherein the conductive element is fixed between two carrier layers, still without intermediate stiffening and height increasing elements.

As shown in <FIG>, the roll-to-roll process can include a further stage wherein the bottom surfaces of the one or more conductive elements are bound to a third substrate layer with a third adhesive. The bottom surfaces of the one or more conductive elements are surfaces of the conducting layer exposed by removing the first substrate layer from them.

In the example of <FIG>, said third substrate layer is a second carrier layer <NUM> and the third adhesive is the carrier binding adhesive. As shown in <FIG>, the second carrier layer can be rolled off a reel <NUM> and a layer of the carrier binding adhesive be applied on a surface of the second carrier layer. This is illustrated by showing a spray station <NUM> in which the releasably binding adhesive is spread on the second carrier layer after it is rolled out the reel <NUM>. However, as mentioned earlier, in this example, the mechanism for providing the carrier binding adhesive is not relevant, as such. Alternative deposition methods include flexograph-, gravure-, offset or screen printing, slot-die or reverse gravure coating, for example. The essential aspect is that the carrier binding adhesive is provided between a surface of the second carrier layer <NUM> and bottom surfaces of the conductive elements so that when these surfaces are put into contact between reels <NUM>, the carrier binding adhesive can be activated to bind the surfaces to each other. The resulting laminate can then be rolled as a final dual-laminate product on a transfer reel <NUM>.

<FIG> illustrates an embodiment showing an alternative way to bind the top surfaces of the one or more conductive elements to a first carrier layer with a carrier binding adhesive. Elements and stages that were shown and explained in <FIG> are denoted in <FIG> with same reference numbers and are not described with this drawing again, further details on these elements can be referred from the description of <FIG>. In the embodiment of <FIG>, a layer of the carrier binding adhesive is formed on the layered web before the patterning stage. Furthermore, the top surfaces of the one or more conductive elements are bound to the first carrier layer by activating adhesion of the carrier binding adhesive after the patterning stage where boundaries of the conductive elements are patterned into the layered web but before the removing stage where the parts of the conducting layer outside the boundaries of the one or more conductive elements are removed from the sacrificial substrate layer.

An advantageous method to implement this is to use pressure sensitive adhesive (PSA) as the carrier binding adhesive. Examples of PSA adhesives include acrylic and silicone based PSA tapes. Many of the PSA products can be roll-to-roll processed, and they are also well applicable in die-cutting and kiss-cutting processes because they typically appear in solid but elastic form that is easy to cut and does not spatter or stick on the cutting tools. It has been detected that specifically acrylic-based PSA products are of the type that provides an appropriate adhesive strength for the purpose. In practise this means that the adhesion by acrylic-based PSA is so much stronger than the adhesive strength of the releasably binding adhesive that it keeps the conductive elements fixed to the first carrier layer even when the sacrificial substrate layer is released by pulling it away from them.

In practise, in order to be roll-to-roll processed, a PSA tape needs to be covered with a release liner, like a silicone covered polymer film. <FIG> shows an implementation where the roll-to-roll process disclosed in <FIG> includes a further PSA reel <NUM> from which a PSA tape <NUM>, which includes a layer of PSA material covered with a release liner is rolled on the layered sheet that rolls out of the nip rolls <NUM>. The PSA tape is oriented so that the layer of PSA material gets into contact with the conducting layer conductor layer of the layered web and the release liner is on the top. The layered web and the PSA tape are pressed together with nip rolls <NUM>, which activates the PSA material, and forms the strong adhesion to the conducting layer in layered web. The release liner can then be removed as a continuous sheet with a reel <NUM>, as shown in <FIG>. The PSA material now forms the carrier binding adhesive, covers the conducting layer, and becomes patterned with it in the cutting tool <NUM>. Parts of the PSA material layer become also removed from the process with the removable parts of the conducting layer when the recessed web is released from the sacrificial substrate layer by means of the reel <NUM>.

Accordingly, after the cutting and recessed web removal stages, the roll-to-roll processed web includes the sacrificial substrate layer and the conductive elements. Bottom surfaces of the conductive elements are bound to the sacrificial substrate layer with the releasably binding adhesive, and top surfaces of the conductive elements are covered with a layer of PSA material. When the roll-to-roll processed web is now put into contact with the first carrier layer <NUM> rolling out of reel <NUM> and pressed on it with nip rolls <NUM>, the top surfaces of the conductive elements become strongly fixed to the first carrier layer <NUM>, and the sacrificial substrate layer <NUM> can be pulled off by rolling it onto the reel <NUM>, as described in <FIG>. The adhesion by the releasably binding adhesive is so much weaker than the adhesion by the PSA material of the carrier binding adhesive that the conductive elements remain fixed to the first carrier layer while the sacrificial substrate layer <NUM> is released from the roll-to-roll processed web. The process may optionally include a further pair of nip rolls <NUM> to finalise the desired lamination and the final product that includes the flexible web of the first carrier sheet with flexible conductive elements without stiffening and/or height increasing reinforcing layers can then be rolled onto a transfer reel <NUM>.

<FIG> illustrates in simplified form stages of the roll-to-roll process described in detail with <FIG>. Further details for the terms and elements discussed herein may be referred from the description of <FIG>. In stage <NUM>, the layered web is formed by binding the conducting layer <NUM> and the sacrificial substrate layer <NUM> to each other with the releasably binding adhesive. Stage <NUM> illustrates the patterning stage wherein a cutting tool <NUM> patterns boundaries of the conductive elements into the layered web <NUM> by cutting though the conducting layer but not through the sacrificial substrate layer. Stage <NUM> illustrates removal of the recessed web <NUM>, formed of the parts of the conducting layer outside the boundaries of the one or more conductive elements from the sacrificial substrate layer. Stage <NUM> illustrates binding the exposed top surfaces <NUM> of the conductive elements to the first carrier layer <NUM>, which is covered with the carrier binding adhesive. Stage <NUM> illustrates removal of the sacrificial substrate layer <NUM> from the one or more conductive elements while the top surfaces of the one or more conductive elements are already bound to the first carrier layer <NUM>. Stage <NUM> illustrates the optional function to create a dual-sided laminate by binding the exposed bottom surfaces <NUM> of the conductive elements to the second carrier layer <NUM>, which is covered with the carrier binding adhesive. Stage <NUM> illustrates rolling of the resulting dual-layer product that includes one or more flexible conductive elements laminated inside two flexible fibrous webs.

<FIG> illustrates an embodiment showing a further alternative way to bind the top surfaces of the one or more conductive elements to a first carrier layer with a carrier binding adhesive so that roll-to-roll processable PSA material can be used as a carrier binding adhesive in both adhesive layers of a dual-laminate product. Elements and stages that were shown and explained in <FIG> are denoted in <FIG> with same reference numbers and are not described with this drawing again, further details on these elements can be referred from the description of <FIG>. In the embodiment of <FIG>, a layer of the carrier binding adhesive is a PSA tape that it is rolled from a reel onto the conductive elements after the patterning stage. The top surfaces of the one or more conductive elements are bound to the first carrier layer before the removing stage where the parts of the conducting layer outside the boundaries of the one or more conductive elements are removed from the sacrificial substrate layer.

<FIG> shows an implementation where the roll-to-roll process disclosed in <FIG> includes a further PSA reel <NUM> from which a PSA tape <NUM>, which includes a layer of PSA material covered with a release liner is rolled on the first carrier layer <NUM> rolling out of reel <NUM>. The first carrier layer <NUM> and the PSA tape are pressed together with nip rolls <NUM>, which activates the PSA material, and forms the strong adhesion to the first carrier layer <NUM>. The release liner can then be removed as a continuous sheet with a reel <NUM>, as shown in <FIG>. The PSA material layer now forms the carrier binding adhesive, and is exposed so that when it is rolled with the roll-to-roll progressing web by the nip rolls <NUM>, the PSA material activates, and forms the strong adhesion between the first carrier layer <NUM> and the top surfaces of the conductive elements.

The roll-to-roll processed web includes now the sacrificial substrate layer, the conductive elements, and the first carrier layer <NUM>. The bottom surfaces of the conductive elements are bound to the sacrificial substrate layer with the releasably binding adhesive, and top surfaces of the conductive elements are fixed to the first carrier layer <NUM>. The sacrificial substrate layer <NUM> can then be pulled off by rolling it onto the reel <NUM>, as described in <FIG>. The adhesion by the releasably binding adhesive is so much weaker than the adhesion by the PSA material of the carrier binding adhesive that the conductive elements remain fixed to the first carrier layer while the sacrificial substrate layer <NUM> et is released from the roll-to-roll processed web. The process may optionally include a further pair of nip rolls <NUM> to finalise the desired lamination and the final product that includes the flexible web of the first carrier layer with flexible conductive elements without stiffening and/or height increasing reinforcing layers can then be rolled onto a transfer reel <NUM>.

As shown in <FIG>, the roll-to-roll process in this embodiment can include a further stage wherein a second carrier layer <NUM> is rolled off a reel <NUM> and a layer of PSA material is rolled on a surface of the second carrier layer. This is illustrated with a further PSA reel <NUM> from which a PSA tape <NUM>, which includes a layer of PSA material covered with a release liner is rolled on the second carrier layer <NUM>. The second carrier layer <NUM> and the PSA tape <NUM> are pressed together with nip rolls <NUM>, which activates the PSA material, and forms the strong adhesion to the second carrier layer <NUM>. The release liner can then be removed as a continuous sheet with a reel <NUM>, as shown in <FIG>. The resulting laminate can then be rolled as a final dual-laminate product on a transfer reel <NUM>.

<FIG> illustrates layers of the roll-to-roll processed web that is fed into the patterning stage (cutting tool <NUM> in <FIG>, stage <NUM> in <FIG>) in the embodiment described with <FIG> and <FIG>. The layered web has a first layer <NUM> that includes the sacrificial substrate layer (denoted as <NUM> in <FIG> and <NUM> in <FIG>). A second layer <NUM> includes the releasably binding adhesive. The third layer <NUM> includes the layer of conductive material in the conducting layer, and the fourth layer <NUM> includes the polymer film covering the layer of conductive material in the conducting layer.

<FIG> illustrates layers of the roll-to-roll processed web that is fed into the patterning stage (cutting tool <NUM> in <FIG>) in the embodiment described with <FIG>. The layered web has a first layer <NUM>, the second layer <NUM>, the third layer <NUM> and the fourth layer <NUM> described with <FIG>, but also a fifth layer <NUM> that includes the layer of PSA material that is used as the carrier binding adhesive. The PSA material provides the strong adhesion between the conducting layer <NUM>, <NUM> and the first carrier layer that binds the patterned conductive elements to the first carrier layer and keeps them fixed also during removal of the first layer <NUM> from the roll-to-roll processed web.

An example product resulting from the roll-to-roll processing methods described in this text is an object that includes a web of fibres and at least one patterned conducting layer adherently bound to the web of fibres with an adhesive. <FIG> shows an exploded view of layers of an exemplary dual-laminate product resulting from the exemplary roll-to-roll processing method described with <FIG> and <FIG>. The product includes at least a first woven or non-woven web of fibres <NUM> (cf. first carrier layer of <FIG> and <FIG>) to which a patterned conducting layer <NUM> is adhesively fixed with a first layer of carrier binding adhesive <NUM>. The product may also include a second woven or non-woven web of fibres <NUM> (cf. second carrier layer of <FIG> and <FIG>) to which the conducting layer <NUM> is adhesively fixed with a second layer of carrier binding adhesive <NUM>. The adhesive layers <NUM>, <NUM> may be formed of a pressure sensitive adhesive tape, or of some other type of non-hardening glue that can be deposited directly on the web of fibres to receive the conductive element in a roll-to-roll processing method.

<FIG> shows an exploded view of layers of an exemplary product resulting from the exemplary roll-to-roll processing method described with <FIG>. The product includes a first woven or non-woven web of fibres <NUM> (cf. first carrier layer of <FIG>) to which a patterned conducting layer <NUM> is adhesively fixed with a first layer of carrier binding adhesive <NUM>. As noted in the description of <FIG>, the carrier binding adhesive <NUM> is advantageously formed of a layer of pressure sensitive material, and has a patterned form that is equal and aligned to the patterned form of the patterned conductive element.

<FIG> illustrate an exemplary product resulting from the roll-to-roll processing method described in this text. <FIG> shows layers of a high pressure laminate (HPL) that may be made of a plurality of layers of resin-impregnated kraft paper, covered by a protective overlay. The layers of HPL are typically manufactured under high pressure, and in high temperatures. HPL is has many uses in commercial and residential projects like benchtops, vanity tops, tables, counters and more. Such products could be greatly enhanced with an integrated electronic device, for example a heater element seamlessly integrated inside the laminate layers. However, the integrated electronic device needs to be very thin so that it does not disrupt the HPL laminate formation. As discussed earlier, the conductive element itself can be made very thin, but conventional methods known from radio frequency identification solutions where the thin antenna is transferred on carrier on a reinforcing paper sheet are not suitable for this purpose. The roll-to-roll process described in this text enables the arrangement shown in <FIG>, wherein a heater element is directly fixed on a kraft paper carrier sheet with an adhesive, without intermediate reinforcing underlay sheets that remain in the resulting laminate product.

<FIG> shows an electrical component <NUM>, for example a heater element, which is now directly glued on a carrier layer <NUM> with an adhesive. The carrier layer <NUM> is a web of fibres, in this specific HPL example, a kraft paper sheet that may the same composition as the other layers <NUM>, <NUM> used to form layers of the laminate. In production, the plurality of layers <NUM>, <NUM>, <NUM>, which now include the layer <NUM> that carries the electronic component <NUM>, are impregnated with resin and exposed to a predefined pressure in a predefined temperature (typically of the order of <NUM> per-square-meter of pressure, under <NUM>+ temperatures) to form an integrated laminate structure that is illustrated in <FIG>. Since the electrical component is applied directly on the carrier layer, the added thickness to the laminate formation is minimal. This means that the functional improvement can be provided to the laminate structure without essentially compromising its original look and form.

<FIG> can be considered to describe also a fiber reinforced composite, wherein a patterned conductive element <NUM> for an electronic functionality is placed between reinforcing fiber layers <NUM>, <NUM>. It is easily seen that an additional carrier or reinforcing layer for the electronic functionality would create an additional material boundary within the body formed of laminate layers <NUM>, <NUM>, <NUM>,. In the absence of such underlay, the composite polymer can penetrate also through parts of the pattern and the reduction of physical and/or chemical bonds is minimised. The structural integrity of the body can thus be maintained, which is very important.

A non-restrictive list of examples of the woven or non-woven elastically deforming webs include textiles, glass-fiber sheets, carbon-fiber sheets, paper sheets, polymer webs and webs of mixtures of these such as aramids, polyolefins (especially ethylene and propylene), liquid crystal polymers, nylon, lycra, cotton, cellulose. A non-restrictive list of examples of conductive elements include heating elements, antennas, conductive tracks, electrodes, current collectors, ground level layers. These can be combined to form, for example, textiles that include a heating element, laminate flooring elements with integrated heaters, fiber enforced composites with integrated heaters, antennas, conductive tracks and current collecting structures, to mention some.

As noted in the description of <FIG>, the adhesion needs to be strong enough to support the very thin conducting layer during the cutting operation to ensure accuracy of the boundaries of the resulting pattern. On the other hand, the releasably binding adhesive needs to be weak enough to enable release of the recessed web of the removable part of the conducting layer, and the sacrificial substrate layer. These two requirements are controversial, and for some structural configurations and roll-to-roll process parameters, it may be difficult to fulfil both requirements with one type of releasably binding adhesive. In a further exemplary embodiment, the roll-to-roll process is configured to include a stage wherein the initial adhesive force of the releasably binding adhesive is reduced before either of the removing stages. Accordingly, the adhesive force may be reduced already before the parts of the conducting layer outside the boundaries of the conductive elements are removed from the sacrificial substrate layer, or then before the conductive elements are removed from the sacrificial substrate layer.

<FIG> illustrates an example embodiment of the latter option. Elements and stages that were shown and explained in <FIG> are denoted in <FIG> with same reference numbers and are not described with this drawing again. Further details on these elements can be referred from the description of any of the previous Figures. In the embodiment of <FIG>, the layer of the carrier binding adhesive is a PSA tape <NUM> that it is rolled from the reel <NUM> onto the first carrier layer <NUM> and binds the top surfaces of the one or more conductive elements to the first carrier layer before the sacrificial substrate layer removing stage.

<FIG> shows an implementation where the roll-to-roll processing method includes a component <NUM> for a pre-releasing stage wherein the initial adhesive force of the releasably binding adhesive is reduced. In <FIG> the component <NUM> is shown in a position after the cutting tool <NUM> and after the recessed web <NUM> has been removed. However, the component <NUM> may be alternatively arranged to a position where it acts upon the roll-to-roll processed web after the cutting tool <NUM> but before the recessed web <NUM> is removed. Such component may be, for example, a source of ultraviolet light, but some other chemical or physical process (e.g. heating, use of a solvent) capable of reducing the adhesive force of an adhesive may be applied within the scope. There exists a group of adhesive materials, that behave otherwise as PSA materials but whose adhesion can be deactivated or at least reduced by exposing the adhesive to ultraviolet light. For example, a commercially available adhesive material behaves like a normal PSA with an adhesive force between <NUM>-<NUM> N/<NUM><NUM>. This supports the described kiss-cutting stage with rather high mechanical forces. Before either of the removal stages, the roll-to-roll progressing web can be exposed to ultraviolet light and this exposure can reduce the adhesive force even down to <<NUM> N/<NUM><NUM>. The stronger initial adhesion provides the support of the sacrificial support layer to the patterned film at the patterning stage, and thus improves the result of the patterning. On the other hand, the reduced adhesion at the time of removal of the extra parts of the conducting layer or the sacrificial substrate layer ensures that removal causes minimal adverse effects to the web that remains in the roll-to-roll progressing process.

In the previous examples, the web to be rolled onto a transfer reel <NUM> includes a carrier layer (e.g. fabric, laminate layer, etc.) to which the conductive element is designed to remain adhesively bound. <FIG> illustrates a further implementation wherein the method disclosed herein is used to create a layered web that enables transfer of large and fragile conductive elements onto a surface selected by the user on site without creating considerable profiles or intermediate top or bottom substrate layers onto the surface. Concrete examples of such use cases include retrofitting large but thin electrical components on 3D formed windmill blades or on planar surfaces like interior walls or floors of buildings. Elements and stages that were shown and explained in <FIG> are denoted in <FIG> with same reference numbers and are not described with this drawing again, further details on these elements can be referred from the description of, for example, <FIG>.

As in the previous examples, boundaries of one or more conductive elements are patterned into a layered web that includes a conducting layer <NUM> bound to a first substrate layer <NUM> with a first adhesive. In the example of <FIG>, the first substrate layer <NUM> is a protective film that can remain attached to the one or more conductive elements until they are transferred to a target surface. Advantageously, the first substrate layer is a transparent polymer film so that the one or more conductive elements can be accurately positioned when they are transferred to the target surface. The first adhesive is a releasably binding adhesive, which may be deposited on the first substrate layer in the process, as shown in <FIG>, or may be readily provided on the polymer film with a protective sheet that is reeled off before the first substrate layer <NUM> is fed into the process. In the example of <FIG>, the conducting layer <NUM> is rolled out of one reel <NUM> and the first substrate layer <NUM> is rolled out of another reel <NUM> and the layers are pressed on each other with nip rolls <NUM>. Alternatively, the layers <NUM>, <NUM> can be laminated to each other in beforehand, and fed to the roll-to-roll process in a readily laminated form.

As in the embodiment of <FIG>, a layer of the second adhesive is formed on the layered web before the patterning stage. Furthermore, after the patterning stage where boundaries of the conductive elements are patterned into the layered web but before the removing stage where the parts of the conducting layer outside the boundaries of the one or more conductive elements are removed from the first substrate layer, top surfaces of the one or more conductive elements are bound to the second substrate layer by activating adhesion of the second adhesive.

An advantageous method to implement this is to use roll-to-roll transferable pressure sensitive adhesive (PSA) tape as the carrier binding adhesive. The constitution and form of a tape enables patterning of the second adhesive with patterning of the conductive elements. In order to be roll-to-roll processed, a PSA tape may need to be covered with a release liner, like a silicone covered polymer film. <FIG> shows an implementation where the roll-to-roll process includes a further PSA reel <NUM> from which a PSA tape <NUM>, which includes a layer of PSA material covered with a release liner is rolled on the layered sheet that rolls out of the nip rolls <NUM>. The PSA tape is oriented so that the layer of PSA material gets into contact with the conducting layer of the layered web and the release liner is on the top. The layered web and the PSA tape are pressed together with nip rolls <NUM>, which activates the PSA material, and forms the strong adhesion to the conducting layer in the layered web. The release liner can then be removed as a continuous sheet with a reel <NUM>, as shown in <FIG>. The PSA material now forms the carrier binding adhesive, covers the conducting layer, and becomes patterned with it in the cutting tool <NUM>. Parts of the PSA material layer become also removed from the process with the removable parts of the conducting layer when the recessed web is released from the sacrificial substrate layer by means of the reel <NUM>.

Accordingly, after the cutting and recessed web removal stages, the roll-to-roll processed web includes the first substrate layer and the conductive elements. Bottom surfaces of the conductive elements are bound to the first substrate layer with the first adhesive, and top surfaces of the conductive elements are covered with a piece of PSA material. When the roll-to-roll processed web is now put into contact with the second substrate layer <NUM> rolling out of reel <NUM> and pressed on it with nip rolls <NUM>, the top surfaces of the conductive elements become strongly fixed to the second substrate layer <NUM>. Advantageously, the first substrate layer <NUM> and the second substrate layer <NUM> are both formed of a transparent polymer film so that the one or more conductive elements can be accurately positioned when they are transferred to a selected target surface. It is now understood that the cutting tool <NUM> cuts the conductive elements and the second adhesive into a same patterned form. The second adhesive that bonds the top surfaces of the conductive elements in this example is thus a piece of pressure sensitive adhesive with a patterned form that is equal and aligned to the form of the patterned conductive element. Parts of the second substrate layer between the conductive elements are not covered by the second releasably binding adhesive. This means that the resulting layered web does not include parts where two adhesive layers would be glued to each other.

The process may optionally include a further pair of nip rolls <NUM> to finalise the desired lamination and the final product that includes fragile conductive elements secured between the two protective substrate layers can then be rolled onto a transfer reel <NUM>.

<FIG> shows an exploded view of layers of an exemplary dual-laminate product resulting from the exemplary roll-to-roll processing method described with <FIG>. The layered web includes a first substrate layer <NUM> covered with a thin layer of first adhesive <NUM>. The combination of the first substrate layer and the first adhesive may be provided by, for example, a silicone covered, transparent polymer film. The layered web also includes a conductive element <NUM> and a piece of second adhesive <NUM> with a patterned form that is equal and aligned to the patterned form of the patterned conductive element <NUM>. The topmost layer is the second substrate layer <NUM>.

When the conductive element is transferred on a selected surface, advantageously the second substrate layer <NUM> is removed first. This means that the first adhesive <NUM> and the second adhesive <NUM> are selected so that adhesion provided by the pattern of second adhesive <NUM> between the top surfaces of the one or more conductive elements <NUM> and the second substrate <NUM> is weaker than adhesion provided by the first adhesive <NUM> between bottom surfaces of the conductive elements <NUM> and the first substrate layer <NUM>. Since the first and second adhesives are not in contact and the second adhesive <NUM> covers only the conductive element <NUM>, the second substrate layer is easily removed from the layered web, and the first substrate layer <NUM> further supports the fragile conductive element during the removal. The second adhesive <NUM> remains attached to the conductive element <NUM> and so the conductive element can be pressed on a target surface so that an adhesive bond is formed. Again, as the conductive element <NUM> is attached to the target surface, it remains fully supported by the first substrate layer <NUM> so even very large conductive elements that include very thin and thus easily wrinkling parts can be safely transferred on any surface. When the adhesive contact of the second adhesive has again been activated by pressing and smoothing the conductive element against the target surface, the first substrate layer <NUM> can be pulled off so that only the conductive element remains attached to the target surface.

Claim 1:
A roll-to-roll processing method, comprising:
binding (<NUM>) a conducting layer (<NUM>) and a first substrate layer (<NUM>, <NUM>) formed of a transparent polymer film to each other with a first adhesive (<NUM>);
attaching a layer of second adhesive (<NUM>) on the conducting layer (<NUM>);
patterning (<NUM>) boundaries of one or more conductive elements (<NUM>, <NUM>), said patterning cutting the boundaries through the layer of second adhesive (<NUM>) and the conducting layer (<NUM>) but not through the first substrate layer (<NUM>, <NUM>);
removing (<NUM>) parts of the conducting layer (<NUM>) and parts of the layer of second adhesive (<NUM>) outside the boundaries of the one or more conductive elements (<NUM>, <NUM>) from the first substrate layer (<NUM>, <NUM>);
binding (<NUM>) top surfaces of the one or more conductive elements (<NUM>, <NUM>) to a second substrate layer (<NUM>, <NUM>) formed of a transparent polymer film with the layer of second adhesive (<NUM>) patterned into a same patterned form as a patterned form of the one or more conductive elements (<NUM>, <NUM>);
rolling (<NUM>) a layered web (<NUM>) on a reel, the layered web including the one or more conductive elements (<NUM>, <NUM>) attached to the first substrate layer (<NUM>, <NUM>) with the first adhesive (<NUM>), and to the second substrate layer (<NUM>, <NUM>) with the layer of second adhesive (<NUM>), which is patterned into the same patterned form as the patterned form of the one or more conductive elements (<NUM>, <NUM>).