The present invention relates to a method of manufacturing an identifiable roofing product provided with one or more devices being able to communi- cate with a read and/or write apparatus by means of radio waves.

According to a first aspect, a method of manufacturing an identifiable roofing product is presented. The method inter alia comprising the steps of providing a first layer of material, and providing a second layer of material onto the first layer of material.

The terms "roof or "roofing", which is employed throughout this specification, applies not solely to an external face of a building. The terms "roof or "roofing" shall however, throughout this specification, be understood as terms identifying a roof as such incl. a space below an outer and typically weather exposed roof covering, such as an attic an the like, whereby the terms also is intended to identify moisture and/or vapour barriers and the like.

Background

Roofing products such as asphalt or bitumen impregnated roof coverings incl. vapour barriers and the like are today difficult to identify upon the product being dispatched from its place of manufacture.

Manufacturers of such roofing materials have a strong desire in obtaining a simple and cost effective method of applying unique, reliable and durable means for identification to their products. Further, manufacturers of the above roof products strive in producing a product comprising an identification system being able to encompass close to an infinite number of identities in order to provide the product with a unique ID being which may be able to possess data translatable e.g. into product ID, date, time and location of manufacture. There are various reasons for such desire, some of which are:

- possibility for determining whether a product is actually manufactured by a particular manufacturer in order to prevent and unveil imitations, - possibility for optimization of internal logistic and handling,

- possibility for identifying stolen products, and

- possibility for tracing the product back to an exact place and time of manufacture.

Up to this day, roofing products like roll roofing and roofing shingles etc. comprising a bitumen impregnated core provided with at least one further layer of bitumen are, for reasons relating to inadequate manufacturing techniques, seldom provided with advanced means for identification, such as RFID tags.

Typical roofing products are, for the above reason, marked only with a simple physical identification on the packaging (wrapping paper or tapes etc.) or a bar code stamp or equivalent on the product itself. Such marking typically consist of a combination of characters constituting an ID of the product.

The markings are usually performed by means of an impression, e.g. from a stamp or a roll arranged in connection with a production line, where the stamp or roll comprises a set of characters which is impressed into the roofing product.

Another common way of identifying a product is by means of an inked stamp applied on the product or on the outer surface of the finished roll of roofing product.

The above techniques hold several drawbacks, some of which are: - difficulties in providing fast changing identifications as the means for impressing into the roofing product typically constitutes fixed characters which are not easily changeable,

- difficulties in locating the impressions on the final product, - poor quality of the impressions as the material of the roofing product tends to stick to the means for impression,

- poor durability due the nature of the asphalt or bitumen based material, as the material, even after application to a roofing structure, holds a degree of indulgence, the impressions over time is smoothed out, and

- imitations of the product incl. identification may be produced relatively easy, as a somewhat exact copy of a stamp is easy obtainable.

Conclusively, manufacturers of roofing products, and in particular layered roofing products like vapour barriers and roof coverings, strive in obtaining a feasible method of manufacturing aforementioned products incorporating advanced means for identification.

One example of a layered vapour barrier is disclosed in the US patent 4567080 A. The patent teaches a vapour barrier comprising two vapour-tight layers and a water absorbing layer interposed there between.

Further, prior art holds a number of methods of identifying roofing products, where one example is GB 179130 A. The document suggests identifying the time and place of origin of a roofing product by means of a thread embedded within or in between layers constituting the product. The colour of the thread is linked to a particular place of manufacture, whereby the origin of the product may be determined. The possible variants of the above identification technique is limited to the number of colours available for the thread, and further, information like production date and exact time of production are not immediately applicable.

An example of a layered roof covering is disclosed in GB 2094226 A, which teach a sealing sheet with an upper layer, a strengthening layer and an underside layer. The sheet is used for covering parts of buildings and roofs.

Today there are more advanced methods of identification available. One of particular interest to manufacturers of roof coverings is the radio frequency identification technique, generally called RFID and described e.g. in US 4384288 A.

The RFID technique relies on remotely storing and retrieving data using de- vices called RFID tags or RFID transponders.

The research disclosure published under publication number XP-002512299 suggests radio frequency identification (RFID) tags being attached to, or during manufacturing; embedded in, building materials such as roofing shingles and roofing tiles etc.

An RFID tag is an object that can be applied to or incorporated into a product for the purpose of identification by means of radio waves. Some tags can communicate over several meters and beyond the line of sight of the reading and/or writing instrument.

RFID tags contain at least two parts. The first part is an integrated circuit for storing and processing information, modulating and demodulating a signal and other specialized functions, and the second part is an antenna for receiv- ing and transmitting the signal. The parts are typically arranged on a base e.g. constituting a piece of foil or a plastic sheet. The tags are in some embodiments sealed by means of a layer of protective foil applied to the surface opposite the base.

RFID tags come in three general varieties: passive, active, or semi-passive.

Passive tags require no internal power source, thus being pure passive devices (they are only active when a reader is nearby to power them via radio waves), whereas semi-passive and active tags require a power source, usu- ally a small battery.

As the passive RFID tags have no internal power supply, the minute electrical current induced in the antenna by the incoming radio frequency signal, is used as power for the electronic circuits in the tag.

A drawback of many of the present RFID tags is that they need an external antenna which is about 80 times larger than the integrated circuit served by the antenna.

RFID tags are today produced in substantial numbers, and the tag by tag cost is typically very low in comparison with the product to which they are applied.

RFID tags may be obtained from various suppliers and in virtually any form, e.g. as a thin "endless" strip from where the tags may be cut one by one.

Another popular way of obtaining a plurality of tags is as thin stickers adhered to a carrying strip. In such embodiments, one surface of the tags is provided with a suitable adhesive. The RFID tags allows read and write of data which at convenience may constitute place, date and time of production, serial number, manufacturer name and product number etc. The RFID tags even allow for multi-bit encryption and password protection of the data written to the chip.

Manufacturers of roofing products such as vapour barriers and asphalt or bitumen based roofing products has been seeking methods of manufacture wherein the products are provided with RFID tags, and until now, no feasible method of large scale production has been found.

RFID tags has to, in order to be substantially invisible, and, as the overall appearance and functionality of the final product incl. RFID tag must be equivalent to the overall appearance product without the RFID tag, be arranged within, or embedded within, the roofing product. As a result of this, it has been found that the RFID tag preferably should be applied to the product during the manufacturing process, and preferably in between layers constituting the product.

Research and attempts in setting up manufacturing processes of roofing products wherein RFID tags are applied have led to various defects within either the RFID tag or the final product as such. Some of the experienced deficiencies are:

- de-lamination of the roofing product in the area of the RFID tag due to the tag changing form from flat to curved as a result of the tag being subjected to the relatively hot manufacturing process,

- damage to the RFID tag as a result of the tag being exposed to the harsh environment within the manufacturing process,

- damage to the roofing product as a result of the RFID tag applicator contacting the often somewhat fluent and tacky surface of the sub- product, and - soiling of parts of the applying station as a result of the RFID tag applicator contacting the often somewhat fluent and tacky surface of the sub-product.

Conclusively, prior art fails to teach a method of applying RFID tags, as solitary tags, by means of a technique which do not require that parts of an applicator or equivalent contact the tacky or even fluent surface of the layers of material.

Brief description of the invention

The present invention seeks to set forth a method of manufacturing an identifiable roofing product which address and solve the abovementioned drawbacks and insufficiencies.

Up to this day, prior art has failed to teach a simple and yet reliable and inexpensive method of manufacturing an identifiable roofing product which, without substantially increasing the production cost of the roofing product incl. process equipment, provides a reliable method of providing roofing products with RFID tags.

According to the invention, there is provided an improved method of manufacture as per the introductory part of this specification, and in particular, upon setting up the method of manufacture such that the method further comprises a step of, prior to providing the second layer of material onto the first layer of material, blowing at least one RFID tag onto the first layer of material by means of pressurized gas or air, the abovementioned insufficiencies of the prior methods of manufacture are overcome.

Conclusively, provision of RFID tags in the form of solitary tags may thereby be provided onto a sub-product of a roofing product without requiring parts of equipment for application of the tags contacting the often wet, fluent or tacky surface of the sub-product.

According to one embodiment, at least one of the materials comprise bitu- men.

According to one embodiment, the first layer of material is a felt or a web impregnated with a material comprising bituminous materials.

According to one embodiment, the first layer is impregnated by means of a first set of rolls and the second layer of material is a material comprising bituminous materials applied by means of a coating station and calendared by means of a second set of rolls arranged subsequent the first set of rolls.

According to one embodiment, the RFID tag is applied onto the first layer of material at a location between the first set of rolls and the second set of rolls.

According to one embodiment, the RFID tag is applied onto the first layer of material in the form of solitary tags or labels.

According to one embodiment, the tags or labels are applied by means of a tamp-blow applicator.

According to one embodiment, the tamp blow applicator comprises an appli- cator head configured for movement towards and away from said sub- product whereby a gap between the sub-product and the applicator head may be controlled dynamically.

According to one embodiment the size of gap between the applicator head and the sub-product is controlled by means of distance measuring. According to one embodiment, release of the RFID tag from the applicator head is controlled inter alia by means of monitoring a distance between the applicator head and the sub-product.

According to one embodiment, the RFID tag is blown onto the first layer of material by means of pressurized and dried atmospheric air.

According to one embodiment, the RFID tag is applied onto the first layer of material while the first layer of material has a temperature of about 125- 150 ⁰ C.

According to one embodiment, the RFID tag is applied onto the first layer of material while the first layer of material is tacky.

According to one embodiment, the RFID tag is, on its two large surfaces, covered with a material having substantially similar thermal coefficient of expansion.

According to one embodiment, the RFID tag may, on at least one of its two large surfaces, be provided with an adhesive.

According to one embodiment, a plurality of RFID tags may be applied to the first layer, in a tab region of the roofing product, close to a butt region, and one by one under a theoretical line being substantially parallel to a longitudi- nal line of the roofing product.

According to one embodiment, the RFID tag is encoded with data prior to being arranged onto the first layer.

According to one embodiment, the method further comprises a step of encoding the RFID tag upon the RFID tag being arranged onto the sub-product. According to a second aspect, a roof covering manufactured according to the present invention is provided.

According to a third aspect, a roof comprising a roofing product manufactured according to the present invention is provided.

According to one embodiment, the product constitutes a vapour barrier.

According to fourth aspect, a process plant adapted to carrying out the method according to the present invention is provided.

According to a fifth aspect, an identifiable roofing product manufactured according to the present invention is provided.

According to a sixth aspect, a roll of identifiable roofing product manufactured according to the present invention is provided.

Brief description of the figures

Figure 1 is a diagrammatic illustration of a station manufacturing a roofing product according to the present invention.

Figure 2 is a top view of a roofing product under manufacture according to figure 1.

Detailed description with reference to the figures

Teachings and steps necessary in order to produce a roofing product, which are not described within this specification, are considered basic knowledge for persons skilled in the art and are for this reason left out of the below exposition.

The below exposition teach a manufacturing process for a length of roof cov- ering constituting a bituminous roofing membrane.

According to one not illustrated embodiment of the present invention, the invention relates to a manufacturing process of a roofing product not constituting a bituminous membrane, such as a vapour barrier to be arranged be- tween an attic and underlying rooms or in-between horizontal divisions of a building.

The roofing product is, according to figure 1 and 2, built up and conveyed from left to right as indicated by the arrow 90.

A base 10 constituting a web e.g. of polyester, metal or glass fibre, is conveyed to an impregnating station 5, 50, 51. The impregnating station 5, 50, 51 impregnates the base 10 by means of two opposed rolls 50, 51 , wherein according to the illustrated embodiment, the lower roll 51 is partially im- mersed in a bath 5 of material such as liquid bitumen or equivalent. As the material is typically non liquid at natural ambient temperatures, the bath 5 may be heated in order to keep the material fluid and applicable to the web by means of the lower roll 51.

The bitumen applied at the impregnating station 5, 50, 51 may constitute pure bitumen, substantially pure bitumen, a bitumen/polymer composition or equivalent.

The impregnated web leaves the impregnation station as a sub-product 20. The temperature of the sub-product 20 after leaving the impregnating station is typically in the range of 125-150 ⁰ C.

The impregnated sub-product 20 is conveyed to a tagging station 2 where a tag 1 , is applied onto the hot surface of the sub-product 20 by means of a tag applicator 4.

The tag 1 may constitute a RFID tag.

The applicator 4 may constitute a tamp-blow applicator comprising an applying head 3 which is adapted to carry the tag 1 to a position near the surface of the sub-product 20 from where the tag 1 is blown onto the surface of the sub-product 20.

Applying a tamp-blow applicator rather than a conventional tag applicator is beneficial to the process of manufacture according the present invention as the applying head 3 of the tamp-blow applicator 2 never contacts the hot and sticky surface of the sub-product 20. The tamp-blow applicator is adapted to move the applying head 3 close to the surface of the sub-product 20 and blow the tag 1 , by means of pressurised gas or air, onto the surface of the sub-product 20.

The pressurised air may advantageously be dried whereby the tag 1 and the sub-product 20 are not exposed to moist often contained in pressurized gas or air.

The applicator 4 applies tags 1 to the surface of the sub-product 20 at controlled intervals, whereby an even longitudinal distance between the tags 1 is obtained. The longitudinal distance may be selected at convenience; how- ever it has been found that a longitudinal distance of abt. 1 meter between the tags 1 will be suitable for most applications. According to one embodiment, the tags 1 are encoded within the tagging station 2, by not shown means adapted to communicate with the tags 1 , whereby the tags 1 are, prior to being placed onto the surface of the sub- product 20, encoded with data like identification of production line, make, order no., serial number, date and time and the like.

It will be possible to control the distance between the tags 1 such that the longitudinal distance between the tags applied to the sub-product 20 is not uniform. This may be due to special requirements and custom orders and the like.

The tamp blow applicator 4 may comprise means (not shown) for sensing the distance between the sub-product 20 and the applying head 3 in order to control blow out of the tag 1 as well as placing the head 3 of the applicator 4 in a suitable height above the sub-product 20. The means may be adapted to compensate for vertical movement and/or vibrations of the sub-product 20.

Some applicators, which contacts the surface of a product to be tagged or labelled, has been found problematic in applications according to the present invention as the hot and to a certain degree liquid material tends to stick to the means of application whereby the process of application is disrupted.

The applicator 4 may be provided to the process of manufacture as a com- plete unit comprising a first spool accommodating a strip wherein the tags 1 prepared for application are arranged. The applicator 4 may further comprise a second spool adapted for receiving the empty strip.

The tags 1 may, at least on a surface facing the sub-product 20, advanta- geously be provided with an adhesive which, despite the sub-product 20 be- ing somewhat fluent as a result of the increased temperature, improve the tags 1 adherence to the sub-product 20.

One type of tags, which has been found less suitable for the application ac- cording to the present invention, is a type which is arranged on a base constituting a first large surface having a different thermal coefficient of expansion than the components of the tag, i.e. the antenna, which constitutes the second large surface of the tag.

Subjecting abovementioned tags to high temperatures may render the tags deform, which may, in the application according to the present invention, render the final product not suitable for its intended purpose. Conversely, should a manufacturer of roofing products request physical marks identifying the location of a tag, this effect may of course be used for the benefit of the manufacturer.

In order to prevent the abovementioned deformation of the tag, it has been found that providing the tag with, on its two large surfaces, a covering of a material having substantially corresponding thermal coefficients of expan- sion. This will to a great extend eliminate the deformation due to stress caused by heat.

In another embodiment of the present invention, the tags may constitute an "endless" strip accommodating the tags and being arranged on the sub- product 20 as one long strip. Further, the strip accommodating the tags, which may or may not be arranged on both sides of the tag, may constitute a film being able to diffuse into the bitumen.

In embodiments wherein the tags are applied to the sub-product 20 in the form of an endless strip (or tape), the strip may be applied to the sub-product 20 by means of a strip applicator. According to figure 1 , the applicator 4 is arranged in a position following the impregnating station 5, 50. The illustrated location is however not essential to method according to the present invention. The applicator 4 may equally ap- ply tags directly on an unimpregnated web 10 or, as an alternative, on a layer of material which is not being built-up from a web.

Following the tag application, the sub-product 20 incl. the applied tag 1 , reaches a coating station 6, 7, 9, 60, wherein at least one layer of material, such as bitumen, is applied. The upper face of the sub-product 20 may be covered with material applied to the process by means of pouring or spraying material stemming from a tank 7 or equivalent, and the lower face of the sub- product 20 is covered with material conveyed to the surface by means of a lower roll 9 partially submerged in material within the bath 6.

The material applied at the coating station 6, 7, 9, 60 may constitute pure bitumen, a bitumen/polymer composition or equivalent, and further, the applied material is not necessarily equivalent to the material applied by the abovementioned impregnating station 5, 50, 51.

As the material is typically non liquid at natural ambient temperatures, the material may be heated in order to keep the material fluid and applicable to the sub-product 20.

The sub-product 20 leaves the coating station 6, 7, 9, 60 as the product 30.

The rolls 9, 60 may constitute calender rolls adapted to exert pressure in opposition to each other through the layers forming the product 30. The purpose of calendering, or levelling, is to smooth out the product 30 and ensure a substantial uniform distribution of the material applied to the sub-product 20 incl. tag 1 within the coating station 6, 7, 9, 60. As can be seen in the figure, the tag 1 is, together with the sub-product 20, conveyed through calendering station.

Tests has shown that, as the material applied to the upper surface of the sub- product 20 is somewhat liquid during the step of calendering, the tag 1 incl. it's rather delicate parts, is able to withstand the stress induced by the rolls 9, 60.

The temperature of the sub-product 30 is immediately after the coating station 6, 7, 9, 60 in the range of 170 - 190 ⁰ C.

Although not shown within the figures, the manufacturing process may encompass successive steps of coating and/or calendering, however these successive steps are considered optional and irrelevant in respect to the present invention.

The product may, following the coating station, be provided with a layer of slate or equivalent by means of an applicator 8.

A read and/or write station 80 may, according to a one embodiment of the present invention, be arranged at a position following the tag application. The station constitutes a device adapted to communicate with the embedded tag 1. The communication may consist of a test of responsiveness of the embed- ded tag 1.

As an alternative, the station 80 may demonstrate equivalent encoding functions to that of the applicator 4, or again as an alternative, the read/write station may be adapted to execute kill commands rendering the tag 1 com- pletely disabled. As the product 30 is conveyed to the slate applicator 8 at an increased temperature, the slate or equivalent is retained to the surface of the product by means of partially immersion.

As an alternative option, following the application of slate or equivalent, the product may again be subject to another step of calendering in order to depress the slate or equivalent into the surface of the product.

The final product 40 incl. tag 1 my be cut into selected lengths and rolled into rolls.

Figure 2 is a top view of a part of a roof covering illustrated during manufacture according to the present invention. As can be seen in the figure, the web 10 is initially impregnated, and upon impregnation, the web 10 forms a sub- product 20 onto which tags 1 are applied. The sub-product 20 incl. tags 1 are then coated whereby another product 32 is formed.

Numeral 32 on figure 2 refers to a butt region of a roof covering, and numeral 40 refers to a tab region of the roof covering. The butt region 31 constitutes a portion prepared for overlapping by a tab region of a roof covering arranged in parallel on a roofing structure. The overlap is typically sealed by means of a welding torch considerably increasing the temperature of the region, which is why the tag 1 should not be arranged within this particular area.

As can be seen in figure 2, the tags 1 are arranged under at theoretical line being substantially parallel with the longitudinal axis of the roof covering in the area close to the butt region 31. Applying the tag 1 in this area has been found beneficial as the roof covering, upon being rolled into rolls and stowed e.g. on pallets, are oriented, due to strength considerations etc., with the butt region 31 facing away from the surface supporting the roll, whereby communicating with the tag is rendered convenient. Communication with the tag 1 embedded within the roofing product may, following the manufacturing process, be conducted by means of a RFID reader/writer, which may be handheld or not, performing radio communica- tion with the tag 1. As the reader/writer is not forming part of the present invention, the device will not receive further elaboration within this specification.

In the above exposition, the described materials making up the roofing prod- uct, is based on bitumen. This may however not in any way be considered as limiting for the scope of the present invention as the roofing products according to the present invention may equally be produced by means of materials like asphalt or rubber. Under manufacturing processes wherein the produced product constitutes a vapour barrier, the materials will of course be chosen accordingly, e.g. metal films or any kind of plastic, such as PE, PVC, EVA or TPE.