Method of producing a laminate

Abstract

A continuous method of forming a laminate comprising a deformable layer, the use of the laminate in wound dressings, and apparatus for use in the methods is disclosed. The laminate comprises a discrete deformable first layer and a substantially continuous second layer. The method comprises supplying a substantially continuous layer of a deformable material at a first feed rate and a substantially continuous second layer at a second feed rate wherein the second feed rate is greater than the first feed rate; cutting the substantially continuous layer of deformable material into discrete portions; transferring the discrete portions of the deformable first layer to a transfer means; transferring the discrete portions of the deformable first layer from the transfer means to a surface of the second layer in predetermined locations on the surface of the second layer such that a surface of the deformable layer is in contact with a surface of the second layer, wherein the method comprises means of adjusting the predetermined location using a feedback loop comprising detector means and adjusting means.

Description

Method of producing a laminateField

[0001] Embodiments of the present disclosure relate to methods for the production of laminated materials comprising deformable layers, their use in wound dressings, and apparatus for use in the methods for the production of laminated materials comprising deformable layers.Background

[0002] Wound dressings used in the medical device industry very often consist of an absorbent pad or pads arranged to form an island on a larger, adhesive coated web of film or fabric. The construction of these multi-layered items is relatively complex. In particular, in the manufacturing process, accurate cutting and positioning of the materials used in the islands can be difficult. This is especially so if the materials are extensible and / or vary in thickness.

[0003] Traditionally, pad materials are unwound from a reel and cut into individual portions. The cut out portions are subsequently transferred to an adhesive coated web. Both the cutting process and the transfer process can introduce tension into the pad materials. This can have the effect of stretching the pad material. This can result in over-sized, under-sized and / or misplaced pads.

[0004] An alternative approach is to run the pad feed at the same web speed as the main film or fabric web. In this technique, the pad would probably be cut from its web in such a way that there was a waste selvedge of pad material. However, this process can generate very high levels of waste.

[0005] It is therefore desirable to formulate a process that mitigates one or all of these problems.Detailed description

[0006] Embodiments disclosed herein relate to continuous methods of forming a laminate wherein the laminate comprises a discrete deformable first layer having first and second surfaces and a substantially continuous second layer having first and second surfaces wherein the method comprises supplying a substantially continuous layer of a deformable material at a first feed rate and a substantially continuous second layer at a second feed rate wherein the second feed rate is greater than the first feed rate; cutting the substantially continuous film of deformable material into discrete portions; transferring the discrete portions of the deformable first layerto a transfer means; transferring the discrete portions of the deformable first layer from the transfer means to the first surface of the second layer in predetermined discrete locations on the first surface of the second layer such that the second surface of the deformable layer is in contact with the first surface of the second layer to form a laminate, wherein the predetermined locations are controlledusing a feedback loop wherein the feedback loop comprises detecting means and adjusting means.

[0007] As used herein, the term "substantially continuous" means, with respect to a component of the process, for example the first or second layer of the laminate, such component is provided in a long, continuous condition, such as on a roll. The term "substantially" is included as any component must inevitably have a finite length. With respect to a process, the term "substantially continuous" is used in its conventional meaning and means that substantially unnecessary to pause the manufacturing process to perform one or more of the steps. With respect to the rate of travel, the term “substantially constant” is used in its conventional meaning and means that the rate does not substantially vary throughout the manufacturing process.

[0008] The feedback loop may be a closed feedback loop. The deformable first layer is applied to the second layer at a nip point. The nip point may be at any suitable point on the discrete portion of the deformable first layer, for example, at the leading edge or trailing edge of the discrete portion of the deformable first layer relative to its direction of movement. The feedback loop may result in adjusting the nip point of the second layer relative to the location of the discrete portions of the deformable first layer on the transfer means. The position of the deformable first layer or the position of the second layer may be adjusted.

[0009] The detecting means may be any suitable detecting means such as a laser detector or a visual detecting means. The detecting means may detect the position of the discrete portion of the deformable first layer relative to the second layer downstream of the nip point.

[0010] The adjusting means may be any suitable adjusting means such as a servo motor or cam and follower. The adjusting means may alternatively be a conveyor belt such as a vacuum conveyor, a pusher peg conveyor or a combination of different types of conveyor belt.

[0011] The feedback loop may result in vertically adjusting the nip position of the second layer relative to the location of the discrete portions of the deformable first layer on the transfer means.

[0012] The vertical adjustment may be achieved using any suitable means. Suitable means may include a servo motor or a cam and follower. The adjustment means may adjust the position of the discrete portions of the deformable first layer orthe second layer. Adjusting the position of the second layer may be achieved by adjusting the position of the means by which the second layer is transported, for example by adjusting the position of the roller or flight roller.

[0013] The feedback loop may result in horizontally adjusting the nip position of the second layer relative to the location of the discrete portions of the deformable first layer on the transfer means.

[0014] The horizontal adjustment may be achieved using any suitable means. Suitable means may include a conveyor belt or a servo motor. The conveyor belt may comprise a vacuum conveyor, a pusher peg conveyor or a combination of different types of conveyor belt. The means may adjust the position of the discrete portions of the deformable first layer or the second layer. Adjusting the position of the second layer may be achieved by adjusting the position of the means by which the second layer is transported, for example by adjusting the position of the roller or flight roller.

[0015] The transfer means may be travelling at substantially the same rate as the deformable first layer.

[0016] On cutting, typically if the deformable material is transferred to a transfer means travelling at a rate that is faster than the feed of the deformable material, the deformable material will typically be under tension and therefore likely to be deformed. This may be exacerbated where the deformable material has a greater thickness and / or extensibility. Without wishing to be bound by theory, by transferring the discrete portions of the deformable material to a transfer means travelling at substantially the same rate as the first feed rate the discrete portions of the deformable material will not be under tension or deformed or will be under less tension or less deformed when they are applied to the first surface of the second layer. This allows the discrete portion to be more accurately and consistently placed on the first surface of the second layer. The transfer means preferably travels at a substantially constant rate, i.e. the rate at which the transfer means travels does not substantially vary throughout the process.

[0017] Typically, the first feed rate may be in the range of 0.7 m / min to 75.0 m / min, typically in the range of 1.0 m / min to 55.0 m / min, 10.0 m / min to 30.0 m / min or 15.0 m / min to 25.0 m / min, typically approximately 20 m / min. Typically, the second feed rate may be approximately double the first feed rate. The second feed rate may be in the range of 2.0 m / min to 105.0 m / min, typically in the range of 20.0 m / min to 60.0 m / min, 30.0 m / min to 50.0 m / min, typically approximately 40 m / min.

[0018] The transfer means may be any suitable transfer means, such as a transfer roller, a conveyor belt or vacuum transfer belt or a combination of thereof. In certain embodiments the transfer means is a vacuum roller rotating at a rate such that the external surface of the cylinder is travelling at substantially the first feed rate. Preferably the vacuum roller is rotating at a substantially constant rate such that the external surface of the cylinder is travelling substantially constantly at substantially the first feed rate. The vacuum rollermay act as the anvil for the cutting means used to cut the substantially continuous layer of deformable material into discrete portions.

[0019] The deformable material may be cut by any suitable cutting means. Preferably the cutting means is a blade such as a knife, preferably a steel or carbide sheeter knife. Preferably the cutting means is a cutting means attached to a roller, preferably a blade such as a knife, preferably a carbide sheeter knife attached to a roller. Alternatively, the cutting means may be a full form rotary die. If such a rotary die is used, non-rectangular / shaped pads may be produced. Any waste produced may be subsequently removed from the die.

[0020] In certain embodiments the transfer means is a transfer roller and the cutting means is attached to a roller, preferably the transfer roller acts as an anvil for the cutting means, preferably the transfer means is a vacuum roller and the cutting means is a blade attached to a roller, most preferably the vacuum roller acts as an anvil for the blade attached to the roller.

[0021] The method may comprise a second transfer means. The second transfer means may travel at substantially the second feed rate wherein the discrete portions of the deformable material are first transferred to the first transfer means and subsequently to the second transfer means, i.e., the second transfer means may accelerate the feed rate of discrete portions from the first feed rate to the substantially second feed rate. For example, the discrete portions may be transferred to a first transfer roller travelling at substantially the first feed rate and then subsequently transferred to a second roller travelling at substantially the second feed rate. Alternatively, the second transfer means may travel at substantially the first feed rate. For example, the discrete portions may be transferred to a first transfer roller travelling at substantially the first feed rate and then may be subsequently transferred to a vacuum transfer belt travelling at substantially the first feed rate before subsequently being transferred to the second layer travelling at the second feed rate. The transfer means may travel at a substantially constant rate.

[0022] The second transfer means may be a transfer roller, a conveyor belt or vacuum transfer belt, a reciprocating applicator or a combination thereof. The second transfer means may be a transfer roller having a larger diameter than the first transfer roller, preferably with a diameter such that the circumference is approximately double that of the first roller. The second transfer means may be a vacuum conveyor, a pusher peg conveyor or a combination of different types of conveyor or conveyor belt. For example, a pusher peg conveyor in combination with an overhead vacuum conveyor or a conveyor belt in combination with an overhead vacuum conveyor. The transfer roller, vacuum conveyor, a pusher peg conveyor or a combination of different types of conveyor or conveyor belt may be used in combination with a reciprocating applicator or may itself comprise areciprocating means. The reciprocating means may be any suitable reciprocating means such as a servo motor, or a cam and follower.

[0023] The first transfer means may be a vacuum roller and the second transfer means may be a vacuum roller having a larger diameter than the first transfer means vacuum roller. The first transfer means may be a vacuum roller and the second transfer means may be a vacuum transfer belt, preferably in combination with a vertically reciprocating applicator, such as a cam and follower, to raise the pad onto the second layer. The first transfer means may be a vacuum roller and the second transfer means may be a pusher peg conveyor to create the spacing of the discrete portions of deformable material in combination with an overhead vacuum conveyor to transfer the pads from the pusher peg conveyor to the second layer. The first transfer means may be a vacuum roller and the second transfer means may be a vacuum conveyor in combination with an overhead vacuum conveyor to transfer the pads from the vacuum conveyor to the second layer.

[0024] Where the second transfer means is a vacuum conveyor, the vacuum conveyor may apply a vacuum to the discrete portions of the deformable material across the full length of the conveyor or the vacuum may be closed off in the vicinity of the transfer point to prevent stretch at the point of application of the discrete portions of the deformable material to the second layer. Preferably the portion of the belt where the vacuum is closed off is at least as long as the length of the discrete portion. The belt of the vacuum conveyor may be formed of any suitable material but preferably has a friction that is sufficient to transport the deformable material but low enough to allow for transfer without deformation. The vacuum conveyor belt may be formed of a polymeric material. Suitable polymeric materials include polyurethanes, silicones, vinyl polymers including poly vinyl chlorides, and nitrile rubbers. The surface of the belt may be textured. Without wishing to be bound by theory, a textured surface is believed to be particularly advantageous for the transport and subsequent transfer of fibrous and foam materials.

[0025] The second layer may be transported through the process by any suitable means. Typically, the second layer may be transported using a roller such as a large diameter assembly drum or a flight roller. The roller may travel at a substantially constant rate, preferably at substantially the second feed rate.

[0026] The method may further comprise additional upstream or downstream steps. Such steps may be suitable for the intended purpose of the laminate. For example, where the laminate is for use in a wound dressing the method may further comprise a step of applying a release liner to the wound contacting surface upstream or downstream of the production of the laminate according to the first embodiment. Additional layers may be added to the laminate produced according to the method of the first embodiment downstream of the production of the laminate according to the first embodiment.Additionally, or alternatively, individual dressings may be cut out and individual dressings may be packaged downstream of the production of the laminate according to the first embodiment.

[0027] Preferably the laminate is suitable for use in a wound dressing. The laminate may form a component of a wound dressing. The laminate may form the wound contact layer of a wound dressing. The laminate may form the backing layer, i.e., the outermost layer, of a wound dressing.

[0028] The deformable layer is any suitable deformable layer for the intended use. When the laminate is for use in a wound dressing, the deformable layer may be an absorbent layer, preferably a foam layer. The foam may be any suitable polymer foam. The foam is aptly a highly conformable hydrophilic foam, aptly an open celled foam, and more aptly the foam is a mixture of open and closed cells. It is desirable that the foam layer absorbs the wound exudate rapidly. Such rapid absorption prevents undesirable pooling of exudate between the dressing and the wound.

[0029] The deformable layer may itself be a multi-layer laminate. When the laminate is for use in a wound dressing the deformable layer may comprise a masking layer. The masking layer may comprise cut outs or windows. Windows provide means of viewing level of exudate in the wound dressing whilst still providing a screen for the majority of the exudate to improve patient comfort. The masking layer may be a completely opaque polymer film having cut-out windows or perforations.

[0030] The second layer may have an adhesive layer applied to one or more surfaces of the second layer. The adhesive may adhere the first layer to the second layer.

[0031] The adhesive(s) may be any adhesive(s) suitable for the end use of the laminate material. Where the laminate material is for use in a wound dressing, preferably one or more of the adhesive layers may be a pressure sensitive adhesive. Aptly the pressure sensitive adhesive layer may be formed from an adhesive which is biocompatible. Suitable adhesives include silicone, hot melt, hydrocolloid or acrylic based adhesive. A pressure sensitive adhesive is preferably applied to the first surface of the second layer.

[0032] Preferably one or more of the adhesive layers may be a wound contacting adhesive. The wound contacting adhesive may be a silicone or acrylic adhesive, typically a silicone adhesive. In particularly preferred embodiments, a pressure sensitive adhesive may be applied to the first surface of the second layer and a silicone wound contacting adhesive may be applied to the second surface of the second layer. Where an adhesive is applied to the second surface of the second layer, the adhesive is typically covered by a removable release liner.

[0033] The release liner may be any suitable material, typically a polymer film such as a polypropylene film or coated paper. The release liner may be a silicone coated release liner. The release liner may have a thickness of 50-200 microns.

[0034] The second layer may be any suitable layer, preferably a substantially non-deformable layer. Preferably the second layer comprises a polymeric film. The polymeric film may be formed from any suitable polymer, e.g., polyurethane, silicone, ethylvinyl acetate, polyethylene, polypropylene, or polyester, or a combination thereof. The second layer may be a wound contact layer.

[0035] The wound contact layer may comprise a perforated wound-side adhesive which can be a silicone adhesive, or a low-tack adhesive to minimise skin trauma on removal. The second layer itself may be perforated. Preferably the perforations in the second layer and the adhesive(s) applied to the second layer are coincident. The second layer may be a perforated polyurethane film that is coated with a skin-compatible adhesive, such as pressure sensitive acrylic adhesive or silicone adhesive.

[0036] The layers of the laminate material may each be removed as a single intact layer however it is to be understood that each layer of the laminate material may itself comprise multiple layers and comprise more than one different material.

[0037] When the laminate is suitable for use as a backing layer in a wound dressing, the second layer may comprise a polymeric film. The polymeric film may be formed from any suitable polymer, e.g., polyurethane, silicone, ethylvinyl acetate, polyethylene, polypropylene, or polyester, or a combination thereof. The backing layer may be a liquid-impermeable, moisture-vapour permeable, breathable film, which allows moisture to evaporate from the dressing.

[0038] According to a further aspect of the invention is provided a laminate material produced according to the methods of the first aspect. According to a still further aspect of the invention is provided a wound dressing comprising a laminate material produced according to the methods of the first aspect. Said laminate materials may have any of the preferred features as set out above in relation to the first aspect of the invention.

[0039] According to a further aspect of the invention there is provided an apparatus for performing the method of the invention.

[0040] The apparatus comprises a cutting means for cutting a deformable material, and a transfer means wherein the transfer means is suitable for transferring the deformable material to a surface of a second material and a closed feedback loop comprising a detecting means and an adjusting means wherein the closed feedback loop detects the position of the deformable material on the second material at a position downstream of the transfer means and adjusts the position of the transfer means accordingly.

[0041] The apparatus may comprise a first transfer means suitable for transferring the deformable material at a first rate and a second transfer means suitable for transferring the deformable material at a second rate wherein the second rate is faster than the first rate and wherein the first transfer means is capable of transferring the deformable material to the second transfer means.

[0042] The components of the apparatus may have preferred features as set out above in relation to the method of the first embodiment.

[0043] Preferably the apparatus further comprises means for ensuring that the first deformable layer and second layer and subsequent laminate follow a predetermined path through the apparatus used for the method. Suitable means will be known to those skilled in the art but include rollers, blades and conveyor belts.

[0044] The apparatus may further comprise additional upstream or downstream components. Such components may be suitable for the intended purpose of the laminate. For example, where the laminate is for use in a wound dressing the apparatus may further comprise means for applying a release liner to the wound contacting surface upstream of the production of the laminate according to the first embodiment. Further laminating means for adding additional layers to the laminate produced according to the method of the first embodiment, cutting means for cutting out individual dressings and packaging means for packaging the individual dressings may be present downstream of the production of the laminate according to the first embodiment.

[0045] The apparatus may comprise a processor and a memory, the memory storing instructions which when executed by the processor cause the apparatus to carry out any of the methods disclosed herein.

[0046] Further preferred features of the components required in the apparatus of the earlier aspect are defined hereinabove in relation to the first and second aspects and may be combined in any combination.

[0047] According to another aspect of the invention, there is provided a computer-readable storage medium comprising instructions, which when executed, cause the apparatus defined in the earlier aspect to perform any of the methods defined herein. The computer- readable storage medium may be non-transitory.BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments of the present disclosure will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:

[0049] FIG. 1 illustrates a dressing comprising a plurality of laminate layers according to some embodiments.

[0050] FIG. 2 illustrates apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0051] FIG. 3 illustrates further apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0052] FIG 4. illustrates further apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0053] FIG 5. illustrates further apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0054] FIG 6. illustrates further apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0055] FIG 7. illustrates further apparatus according to some embodiments and suitable for use according to the method of some embodiments.

[0056] In the drawings, corresponding reference characters indicate corresponding components. The skilled person will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various example embodiments. Also, common but well- understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in orderto facilitate a less obstructed view of these various example embodiments.Detailed description

[0057] Figure 1 shows an exploded perspective view of a wound dressing according to an embodiment of the present disclosure. The wound dressing 100 includes a number of layers that are built up in a generally laminar fashion to form a dressing having a relatively planar form. The wound dressing 100 includes a border region 110 extending around the outer periphery of the dressing. The central region may be predetermined to suit a particular wound or particular wound type. Here the border region has the general function of providing an area for sealingly engaging with a patient’s skin surrounding a wound site to form a sealed cavity over the wound site. The central region is the location of further functional elements of the wound dressing.

[0058] The dressing 100 includes a top film 102, a superabsorber layer 103, a perforated wound contact layer 101 , a layer of absorbent material 104 of a suitable size to cover the recommended dimension of wounds corresponding to the particular dressing size chosenand a masking layer 105, allowing partial masking of the top surface of the superabsorber, where coloured exudate would remain.

[0059] The wound contact layer 101 may be a perforated polyurethane film that is coated with a skin-compatible adhesive, such as pressure sensitive acrylic adhesive or silicone adhesive. The skin-compatible adhesive is coated on the lower side of the layer 101 , i.e., the side that is to contact the patient.

[0060] The absorbent layer may be a foam layer, the foam may be any suitable polymer foam. The foam is aptly a highly conformable hydrophilic foam, aptly an open celled foam, or a mixture of open and closed cells.

[0061] It is desirable that the foam layer absorbs the wound exudate rapidly. Such rapid absorption prevents undesirable pooling of exudate between the dressing and the wound.

[0062] The masking layer 105 is a completely opaque polymer film having cut-out windows or perforations to allow for visibility of the superabsorbent layer which can be used by clinicians to assess whether the dressing needs to be changed.

[0063] The top film 102 is a cover layer for covering the lower layers of the dressing, helping to encapsulate the layers between the wound contact layer and the top film. The top film 102 may be a layer of polyurethane. The top film may be coated with any suitable adhesive. Aptly the adhesive will be a pressure sensitive adhesive e.g., acrylic adhesive or silicone adhesive.

[0064] As such, the top film 102 helps to ensure that the dressing remains breathable, i.e., allows a proportion of fluid absorbed in the dressing to be evaporated via the outer surface of the dressing. In this way certain fluid content of the exudate can be transpired from the dressing, reducing the volume of remaining exudate and increasing the time before the dressing becomes full. Also, the top cover 102 helps to ensure that the border region 110 of the dressing remains breathable, i.e., allows a patient’s normal skin perspiration to be evaporated through the dressing, which helps in preventing or minimising skin maceration.

[0065] The outer layer of dressings of the present disclosure when present can be a continuous conformable film. The continuous moisture vapour transmitting conformable film outer layer of the wound dressing may be used to regulate the moisture loss from the wound area under the dressing and also to act as a barrier to bacteria so that bacteria on the outside surface of the dressing cannot penetrate to the wound area. Suitable continuous conformable films will have a moisture vapour transmission rate of at least 300, aptly from 300 to 5000 grams preferably 500 to 2000 grams / square meter / 24 hrs at 37.5 C at 100% to 10% relative humidity difference. Such moisture vapour transmission rate of thecontinuous film allows the wound under the dressing to heal under moist conditions without causing the skin surrounding the wound to macerate.

[0066] The laminate sheet materials of the invention may comprise the superabsorber and masking layers 103, 105 as the deformable first layer and the top film 102 as the second layer or the absorbent layer 104 as the deformable first layer and the wound contact layer 101 as the second layer as shown in Figure 1 .

[0067] The method may be performed using an apparatus as shown in Figures 2-7. Figure 2 is a schematic representation of an apparatus 200 for the production of a laminated material 201 . The apparatus 200 comprises a cutting means in the form of a carbide sheeter knife on a roller 210, transfer means in the form of a vacuum anvil 220, and means for transporting the second layer in the form of a large diameter assembly drum 230. The apparatus may take the form of a machine or a combination or series of machines arranged in a production line and suitable for mass production. A deformable material 240 is fed between the carbide sheeter knife 210 and the vacuum anvil 220. The deformable foam material 240 is travelling at the first feed rate. The vacuum anvil 220 is rotating at a rate that results in the surface of the vacuum anvil travelling at a rate that is substantially the same as the first feed rate. The vacuum anvil is travelling at a substantially constant rate. The carbide sheeter knife 210 cuts the deformable foam material 240 into discrete portions 250 which are simultaneously transferred to the surface of the vacuum anvil 220. The second layer 260 travels around the large diameter assembly drum 230 at a second feed rate which is approximately twice the first feed rate. The large assembly drum travels at a substantially constant rate. The second layer 260 typically has a pressure sensitive adhesive layer applied to its first surface 270. As the vacuum anvil 220 rotates the discrete portions 250 of the deformable first layer are transferred to the adhesive coated first surface 270 of the second layer at regular predetermined intervals. A closed loop control system 290 comprising a detecting means 291 in the form of a laser or vision detector locates the leading edge of the discrete portion of the deformable material 250 on the first surface of the second layer 270 and an adjusting means 292 in the form of a servo motor adjusts the horizontal position of the large diameter assembly drum 230 relative to the nip point of the discrete portions of the deformable material 250 with the first surface of the second layer 270 to accurately locate the discrete portion of the deformable material 250 on the second layer 270.

[0068] Figure 3 is a schematic of an apparatus 300 for use in the method of producing a laminate 301 according to the first embodiment. This apparatus differs from that of Figure 2 in that the servo motor 392 adjusts the vertical position of the large diameter assembly drum 330 relative to the nip point of the discrete portions of the deformable material 350 with the first surface of the second layer 370.

[0069] Figure 4 is a schematic of a further apparatus 400 for use in the method of producing a laminate 401 according to the first embodiment. This apparatus differs from that of Figure 2 in that a second transfer means, a large diameter vacuum transfer roller 480 is present and located between the vacuum anvil 420 and the large diameter assembly drum 430. The large diameter vacuum transfer roller 480 transfers the discrete portions of the deformable material 450 from the vacuum anvil 420 to the second layer 460. The outer surface of the large diameter vacuum transfer roller 480 is travelling at a rate equal to that of the feed rate of the second layer 460, i.e., the large diameter vacuum transfer roller 480 accelerates the discrete portions of the deformable material 450 from the first feed rate to the second feed rate. The large diameter vacuum transfer roller travels at a substantially constant rate.

[0070] Figure 5 is a schematic of an apparatus 500 for use in the method of producing a laminate 501 according to the first embodiment. This apparatus differs from that of Figure 4 in that the transfer means comprises a vacuum transfer belt 591 and cam and follower 592 as the second transfer means. The vacuum transfer belt may travel at a substantially constant rate. The vacuum transfer belt may travel at the first feed rate. The cam and follower is driven by a servo motor. The cam and follower may be adjusted by means of an optional feedback loop. The vacuum transfer belt may apply a vacuum to the discrete portions of the deformable material across the full length of the belt or the vacuum may be closed off in the vicinity of the cam and follower to prevent stretch at the point of application of the discrete portions of the deformable material to the second layer. Contact with adhesive applied to the second layer pulls the discrete portions of the deformable material onto the second layer. The surface of the vacuum transfer belt may be textured.

[0071] Figure 6 is a schematic of an apparatus 600 for use in the method of producing a laminate 601 according to the first embodiment. This apparatus differs from that of Figure 2 in that a flight roller 631 with cam and follower 632 replaces the large diameter assembly drum.

[0072] Figure 7 is a schematic of an apparatus 700 for use in the method of producing a laminate 701 according to the first embodiment. This apparatus differs from that of Figure 4 in that a pusher peg conveyor 791 is the second transfer means and runs at substantially the second feed rate. The pusher peg conveyor may travel at a substantially constant rate. An overhead vacuum conveyor 792 transfers the discrete portions of the deformable material 750 from the pusher peg conveyor 791 to the second layer 760 and the second layer 760 is moved through the apparatus using a flight roller 730. The pusher peg conveyor 791 creates the desired spacing of the discrete portions. In alternative embodiments the pusher peg conveyor may be replaced by a vacuum belt.

[0073] Although the present disclosure includes certain embodiments, examples and applications, it will be understood by those skilled in the art that the present disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments or uses and obvious modifications and equivalents thereof, including embodiments which do not provide all of the features and advantages set forth herein. Accordingly, the scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments herein and may be defined by claims as presented herein or as presented in the future.

[0074] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, or steps. Thus, such conditional language is not generally intended to imply that features, elements, or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Further, the term “each,” as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term “each” is applied.

[0075] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0076] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1 % of, within less than 0.1 % of, and within less than 0.01 % of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

[0077] The terms “laminate” and “laminate material” are used interchangeably.

[0078] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

Claims

Claims1 . A continuous method of forming a laminate wherein the laminate comprises a discrete deformable first layer having first and second surfaces and a substantially continuous second layer having first and second surfaces wherein the method comprises supplying a substantially continuous layer of a deformable material at a first feed rate and a substantially continuous second layer at a second feed rate wherein the second feed rate is greater than the first feed rate; cutting the substantially continuous layer of deformable material into discrete portions; transferring the discrete portions of the deformable first layer to a transfer means; transferring the discrete portions of the deformable first layer from the transfer means to the first surface of the second layer in predetermined locations on the first surface of the second layer such that the second surface of the deformable layer is in contact with the first surface of the second layer, wherein the method comprises means of adjusting the predetermined location using a feedback loop comprising detector means and adjusting means.

2. The method according to claim 1 wherein the feedback loop is a closed feedback loop.

3. The method according to claim 1 or claim 2 wherein the adjusting means comprises vertically adjusting the position of the second layer relative to the first layer, preferably using a servo motor or a cam and follower.

4. The method according to claim 1 or claim 2 wherein the adjusting means comprises horizontally adjusting the position of the second layer relative to the first layer, preferably using a servo motor, a cam and follower, or a conveyor belt.

5. The method according to claim 4 wherein the conveyor belt is a pusher peg belt, a vacuum belt or a combination thereof.

6. The method of any preceding claim wherein the transfer means is travelling at substantially the same rate as the substantially continuous layer of a deformable material.

7. The method according to claim 1 wherein the transfer means travels at a substantially constant rate.

8. The method according to any preceding claim wherein the transfer means is a vacuum roller.

9. The method according to any preceding claim wherein the cutting means is a blade attached to a roller, preferably wherein the blade is a carbide sheeter knife.

10. The method according to claim 9, wherein the transfer means acts as an anvil for the cutting means.11 . The method according to any preceding claim wherein said method further comprises a second transfer means.

12. The method of claim 11 wherein the second transfer means is a transfer roller or a vacuum conveyor.

13. The method according to claim 11 or claim 12 wherein said second transfer means accelerates the feed rate of the discrete portions of the deformable material to substantially the second feed rate.

14. The method of any preceding claim wherein the first layer is an absorbent layer, preferably a foam layer.

15. The method of any preceding claim wherein the second layer is a substantially non- deformable layer, preferably the second layer comprises a polymeric film.

16. The method of any preceding claim wherein the second layer has an adhesive layer applied to the first surface of the second layer.

17. The method of any preceding claim wherein the laminate is suitable for use in a wound dressing.

18. A laminate producible by the method of any preceding claim.

19. A wound dressing comprising a laminate according to claim 18.

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