Patent Description:
Large, flexible polymeric sheets, which are often referred to as membranes or panels, are used in the construction industry to cover flat or low-sloped roofs. These membranes provide protection from the environment particularly in the form of a waterproof barrier. As is known in the art, commercially popular membranes include thermoset membranes such as those including cured EPDM (i.e. ethylene-propylene-diene terpolymer rubber) or thermoplastics such as TPO (i.e. thermoplastic olefins).

These membranes are typically delivered to a construction site in a bundled roll, transferred to the roof, and then unrolled and positioned over the roof surface. The sheets are then secured to the building structure by employing varying techniques such as mechanical fastening, ballasting, and/or adhesively adhering the membrane to the roof. The roof substrate to which the membrane is secured may be one of a variety of materials depending on the installation site and structural concerns. For example, the surface may be a concrete, metal, or wood deck, it may include insulation or recover board, and/or it may include an existing membrane.

In addition to securing the membrane to the roof-which mode of attachment primarily seeks to prevent wind uplift-the individual membrane panels, together with flashing and other accessories, are positioned and adjoined to achieve a waterproof barrier on the roof. Typically, the edges of adjoining panels are overlapped, and these overlapped portions are adjoined to one another through a number of methods depending upon the membrane materials and exterior conditions. For example, a seam can be prepared by applying a liquid adhesive or a solid tape. Or, where the membranes are thermoplastic, a seam can be formed by heat welding adjacent overlapping membranes.

Where the membranes are adhesively secured to a roof substrate, several modes of adhesive attachment are known. One attractive mode includes the use of a pre-applied (i.e. factory-applied) adhesive that is applied to the surface of the membrane. These membranes, which are commonly referred to as peel-and-stick membranes, may employ a variety of adhesive compositions, including those applied as a hot melt, including styrene-ethylene-butylene-styrene (SEBS), butyl-based adhesives, EPDM-based adhesives, acrylic adhesives, styrene-butadiene adhesives, polyisobutylene adhesives, and ethylene vinyl acetate adhesives.

In view of the nature of the adhesives that have been employed in peel-and-stick membranes, the roofing systems constructed of these membranes have inherent limitations. Specifically, there are temperature windows that limit the minimum temperature at which the membranes can be installed on a roof surface. Also, there are maximum temperature limits on the roof surface that the adhesive can withstand while maintaining wind-uplift resistance. With respect to the latter, where the surface temperature on the roof nears the glass transition temperature of the adhesive, the adhesive strength offered by the pressure-sensitive adhesive is not maintained. As a result, peel-and-stick membranes have not gained wide acceptance in the industry. Moreover, the use of peel-and-stick membranes has been limited to use in conjunction with white or highly reflective membranes (e.g., white thermoplastic membranes) because the surface temperature of these membranes remains cooler when exposed to solar energy.

While peel-and-stick membranes have been used commercially (with limited acceptance), attempts to use the factory-applied adhesive for seaming adjacent membranes has been problematic. The seams between membranes are subjected to conditions not typically present under the membrane (i.e. where the membrane is attached to the underlying substrate), and it is believed that these factors lead to the failure of seams formed using the same pressure-sensitive adhesives used to secure the membrane to the roof surface. For example, as disclosed in <CIT>, it is believed that temperature swings and moisture contributes to the premature failure of these seams. As a result, thermoplastic peel-and-stick membranes are often manufactured with an "open" lap edge (i.e. a lap without an adhesive layer) so that the seams of these thermoplastic membranes can be heat welded. Alternatively, as disclosed in <CIT>, adhesive tapes (such as butyl-based adhesive tapes) are applied along the lap edge in lieu of the pressure-sensitive adhesive applied to the remainder of the membrane. It has also been proposed, although with limited success, to factory prime the upper surface of the adjoining membrane in an attempt to improve the seam. < page 3a to be inserted>.

The present invention provides a roof system of claim <NUM>. Preferred embodiments of same are the subject matter of claims <NUM> to <NUM>.

Yet other embodiments of the present invention provide a method of installing a roof system according to claim <NUM>, a preferred embodiment of which is the subject of claim <NUM>.

<CIT> relates to a membrane composite comprising a polymeric membrane panel, and adhesive layer, and a release liner, wherein the adhesive layer is a pressure-sensitive adhesive that is at least partially cured, and includes at least two distinct regions with the at least two regions having distinct states of cure.

Still yet other embodiments of the present invention provide a membrane composite of claim <NUM>, which a preferred embodiment of same being the subject of claim <NUM>.

Embodiments of the invention are based, at least in part, on the discovery of a roof system wherein a single-ply membrane is adhered to a roof substrate through a factory-applied adhesive layer, and adjoining membranes are seamed to each other through the same factory-applied adhesive layer. According to aspects of the invention, the factory-applied adhesive layer includes a cross-linked adhesive that is applied to the membrane as a hot melt. Advantageously, in one or more embodiments, the adhesive employed to secure the membrane to the roof, which is the same adhesive used to seam adjacent membranes, is substantially consistent throughout the adhesive layer, particularly with regard to similarity and composition, thickness, and cure state. While the prior art contemplates the use of factory-applied adhesive layers that can both adhere the membrane to the roof and seam adjoining membranes, it has unexpectedly been discovered that the adhesive employed in the present invention can form a seam that does not suffer from the shortcomings of prior art systems.

A membrane composite according to embodiments of the present invention can be described with reference to <FIG>, which shows membrane composite <NUM> including polymeric planar body <NUM>, adhesive layer <NUM>, and release member <NUM>. Planar body <NUM> includes top planar surface <NUM>, bottom planar surface <NUM>, first lateral edge <NUM>, and second lateral edge <NUM>. Adhesive layer <NUM>, which is a pressure sensitive adhesive, is disposed on bottom planar surface <NUM> and extends the entire width of planar body <NUM> from first lateral edge <NUM> to second lateral edge <NUM>. Release member <NUM> covers adhesive layer <NUM> on a surface thereof opposite planar body <NUM>. In particular embodiments, release member <NUM> includes perforation <NUM>, which allows release member <NUM> to be removed in segments in order to separately expose roof-surface contacting portion <NUM> and lap area portion <NUM> of layer <NUM>. Alternatively, the same functionality can be achieved by employing two separate release members, one removably affixed to roof-surface contacting portion <NUM> and the other attached to lap area portion <NUM>.

A roof system according to embodiments of the present invention can be described with reference to <FIG>, which shows roof system <NUM> including first membrane composite <NUM> and second membrane composite <NUM>, which are both adhesively secured to roof substrate <NUM>. Specifically, membrane composite <NUM> is adhesively secured to substrate <NUM> through adhesive layer <NUM> along a roof-surface contacting region <NUM>. And, membrane composite <NUM> is secured to roof substrate <NUM> through adhesive layer <NUM> along a roof-substrate contacting region <NUM>. Additionally, adhesive layer <NUM> of composite membrane <NUM> is adhesively mated to membrane composite <NUM>, on an upper surface <NUM> thereof, to form a lap seam <NUM>.

In one or more embodiments, the pressure-sensitive adhesive layer (e.g. layer <NUM>) is a cured pressure-sensitive adhesive. In sub-embodiments thereof, this cured pressure-sensitive adhesive layer is formed from a curable hot-melt adhesive. In other words, and as will be described in greater detail below, an uncured adhesive composition is applied to the membrane as a hot-melt composition (i.e. the composition is heated and applied as a flowable composition in the absence or appreciable absence of solvent), and then the composition is subsequently crosslinked (i.e. cured) to form the cured pressure-sensitive layer.

In one or more embodiments, the cured pressure-sensitive adhesive layer may be an acrylic-based hot-melt adhesive. In one or more embodiments, the adhesive is a polyacrylate such as a polyacrylate elastomer. In one or more embodiments, useful polyacrylates include one or more units defined by the formula:
<CHM>
where each R<NUM> is individually hydrogen or a hydrocarbyl group and each R<NUM> is individually a hydrocarbyl group. In the case of a homopolymer, each R<NUM> and R<NUM>, respectively, throughout the polymer are same in each unit. In the case of a copolymer, at least two different R<NUM> and/or two different R<NUM> are present in the polymer chain.

In one or more embodiments, hydrocarbyl groups include, for example, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl, substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups, with each group containing in the range of from <NUM> carbon atom, or the appropriate minimum number of carbon atoms to form the group, up to about <NUM> carbon atoms. These hydrocarbyl groups may contain heteroatoms including, but not limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms. In particular embodiments, each R<NUM> is an alkyl
group having at least <NUM> carbon atoms. In particular embodiments, R<NUM> is hydrogen and R<NUM> is selected from the group consisting of butyl, <NUM>-ethylhexyl, and mixtures thereof.

In one or more embodiments, the polyacrylate elastomers that are useful as adhesives in the practice of this invention may be characterized by a glass transition temperature (Tg) of less than <NUM>, in other embodiments less than -<NUM>, in other embodiments less than -<NUM>. In these or other embodiments, useful polyacrylates may be characterized by a Tg of from about -<NUM> to about <NUM>, in other embodiments from about -<NUM> to about -<NUM>, and in other embodiments from about -<NUM> to about -<NUM>.

In one or more embodiments, the polyacrylate elastomers that are useful as adhesives in the practice of this invention may be characterized by a number average molecular weight of from about <NUM> to about <NUM>/mole, in other embodiments from about <NUM> to about <NUM>/mole, in other embodiments from about <NUM> to about <NUM>/mole, in other embodiments from about <NUM> to about <NUM>/mole, in other embodiments from about <NUM> to about <NUM>/mole, and in other embodiments from about <NUM> to about <NUM>/mole.

In one or more embodiments, the polyacrylate elastomers that are useful as adhesives in the practice of this invention may be characterized by a Brookfield viscosity at <NUM> of from about <NUM>,<NUM> to about <NUM>,<NUM> cps (mPa s), in other embodiments from about <NUM>,<NUM> to about <NUM>,<NUM> cps, in other embodiments from about <NUM>,<NUM> to about <NUM>,<NUM> cps (mPa s), in other embodiments from about <NUM>,<NUM> to about <NUM>,<NUM> cps (mPa s), in other embodiments from about <NUM>,<NUM> to about <NUM>,<NUM> cps (mPa s), and in other embodiments from about <NUM>,<NUM> to about <NUM>,<NUM> cps (mPa s).

Specific examples of polyacrylate elastomers that are useful as adhesives in the practice of the present invention include poly(butylacrylate), and poly(<NUM>-ethylhexylacrylate). These polyacrylate elastomers may be formulated with photoinitiators, solvents, plasticizers, and resins such as natural and hydrocarbon resins. The skilled person can readily formulate a desirable adhesive composition. Useful adhesive compositions are disclosed, for example, in <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

In other embodiments, the polyacrylate elastomers may include polymerized units that serve as photoinitiators. These units may derive from copolymerizable photoinitiators including acetophenone or benzophenone derivatives. These polyacrylate elastomers and the adhesive compositions formed therefrom are known as disclosed in <CIT> and <CIT>.

Useful adhesive compositions are commercially available in the art. For example, useful adhesives include those available under the tradename acResin (BASF), those available under the tradename AroCure (Ashland Chemical), and NovaMeltRC (NovaMelt). In one or more embodiments, these hot-melt adhesives may be cured (i.e., crosslinked) by UV light.

In one or more embodiments, the hot-melt adhesive is at least partially cured after being applied to the membrane, as will be discussed in greater detail below. In one or more embodiments, the adhesive is cured to an extent that it is not thermally processable in the form it was prior to cure. In these or other embodiments, the cured adhesive is characterized by a cross-linked infinite polymer network. While at least partially cured, the adhesive layer of one or more embodiments is essentially free of curative residue such as sulfur or sulfur crosslinks and/or phenolic compounds or phenolic-residue crosslinks.

According to the invention, the degree of cure throughout the adhesive layer (i.e., adhesive layer <NUM> from first lateral edge <NUM> to second lateral edge <NUM>) has a substantially consistent degree of cure. In one or more embodiments, the degree of cure throughout the entire adhesive layer varies by no more than <NUM>%, in other embodiments by no more than <NUM>%, and in other embodiments by no more than <NUM>%. In one or more embodiments, the degree of cure is substantially consistent, which refers to an unappreciable variation in the cure state. In one or more embodiments, the cure state of the entire adhesive layer, which for example runs from first lateral edge <NUM> to second lateral edge <NUM>, can be quantified based upon gel content. As a skilled person appreciates, gel content can be determined based upon the level of insoluble material following solvent extraction, which for purposes of this specification refers to solvent extraction using THF at its boiling point following four hours of extraction. These extraction techniques can be performed, for example, using Soxhlet extraction devices. In one or more embodiments, the gel content of the cured adhesive layer, based upon a THF extraction at the boiling point of THF after four hours, is at least <NUM>%, in other embodiments at least <NUM>%, and in other embodiments at least <NUM>% by weight. In these or other embodiments, the gel content is less than <NUM>%, in other embodiments less than <NUM>%, and in other embodiments less than <NUM>%. In one or more embodiments, the gel content is from about <NUM>% to about <NUM>%, in other embodiments from about <NUM>% to about <NUM>%, and in other embodiments from about <NUM>% to about <NUM>% by weight.

As indicated above, the pressure-sensitive adhesive, in its cured stated, provides sufficient tack to allow the membrane composites of this invention to be used in roofing systems that meet industry standards for wind uplift resistance. In one or more embodiments, this tack may be quantified based upon the peel strength when adhered to another membrane in accordance with ASTM D-<NUM>-<NUM>. In one or more embodiments, the cured pressure-sensitive adhesive of the present invention is characterized by a peel strength, according to ASTM D-<NUM>-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in).

Similarly, the tack of the pressure-sensitive adhesive, in its cured state, may be quantified based upon the peel strength when adhered to a construction board (e.g. insulation board) having a kraft paper facer in accordance with ASTM D-<NUM>-<NUM> (<NUM>). In one or more embodiments, the cured pressure-sensitive adhesive of the present invention is characterized by a peel strength, according to ASTM D-<NUM>-<NUM> (<NUM>) using an insulation board with kraft paper facer, of at least <NUM> N/m (<NUM> lbf/in),.

in other embodiments at least <NUM> N/m(<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m(<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in).

In one or more embodiments, the release member (e.g. release member <NUM>), which may also be referred to as a release liner or release paper, may include a polymeric film or extrudate, or in other embodiments it may include a cellulosic substrate. In one or more embodiments, the polymeric film and/or cellulosic substrate can carry a coating or layer that allows the polymeric film and/or cellulosic substrate to be readily removed from the adhesive layer after attachment. This polymeric film or extrudate may include a single polymeric layer or may include two or more polymeric layers laminated or coextruded to one another.

Suitable materials for forming a release member that is a polymeric film or extrudate include polypropylene, polyester, high-density polyethylene, medium-density polyethylene, low-density polyethylene, polystyrene or high-impact polystyrene. The coating or layer applied to the film and/or cellulosic substrate may include a silicon-containing or fluorine-containing coating. For example, a silicone oil or polysiloxane may be applied as a coating. In other embodiments, hydrocarbon waxes may be applied as a coating. As the skilled person will appreciate, the coating, which may be referred to as a release coating, can be applied to both planar surfaces of the film and/or cellulosic substrate. In other embodiments, the release coating need only be applied to the planar surface of the film and/or cellulosic substrate that is ultimately removably mated with the adhesive layer.

In one or more embodiments, the release member is characterized by a thickness of from about <NUM> to about <NUM> µm, in other embodiments from about <NUM> to about <NUM> µm, and in other embodiments from about <NUM> to about <NUM> µm.

In one or more embodiments, the thickness of the pressure-sensitive adhesive layer (e.g. layer <NUM>) may be at least <NUM>, in other embodiments at least <NUM>, in other embodiments at least <NUM>, and in other embodiments at least <NUM>. In these or other embodiments, the thickness of the pressure-sensitive adhesive layer may be at most <NUM>, in other embodiments at most <NUM>, in other embodiments at most <NUM>, in other embodiments at most <NUM>, and in other embodiments at most <NUM>. In one or more embodiments, the thickness of the pressure-sensitive adhesive layer may be from about <NUM> to about <NUM>, in other embodiments from about <NUM> to about <NUM>, in other embodiments from about <NUM> to about <NUM>, and in other embodiments from about <NUM> to about <NUM>.

In one or more embodiments, the membrane, which may be referred to as a panel (e.g. panel <NUM>) may be a thermoset material. In other embodiments the membrane may be a thermoformable material. In one or more embodiments, the membrane may be EPDM based. In other embodiments, the membrane may be TPO based. In these or other embodiments, the membrane may be flexible and capable of being rolled up for shipment. In these or other embodiments, the membrane may include fiber reinforcement, such as a scrim. In one or more embodiments, the membrane includes EPDM membranes including those that meet the specifications of the ASTM D-<NUM>. In other embodiments, the membrane includes thermoplastic membranes including those that meet the specifications of ASTM D-<NUM>-<NUM>. Still other membranes may include PVC, TPV, CSPE, and asphalt-based membranes.

In one or more embodiments, the roofing membrane panels are characterized by conventional dimensions. For example, in one or more embodiments, the membrane panels may have a thickness of from about <NUM> µm to about <NUM>, in other embodiments from about <NUM>,<NUM> µm to about <NUM>, and in other embodiments from about <NUM>,<NUM> µm to about <NUM>. In these or other embodiments, the membrane panels of the present invention are characterized by a width of about <NUM> to about <NUM>, in other embodiments from about <NUM> to about <NUM>, and in other embodiments from about <NUM> to about <NUM>.

Practice of the present invention is not necessarily limited by the selection of any particular roof substrate to which the membranes can be attached in forming the roof systems of the present invention. In one or more embodiments, the roof substrate may include the roof deck. In other embodiments, the roof substrate may include an intervening construction layer disposed above the roof deck. As the skilled person will appreciate, these intervening layers may include, but are not limited to, insulation boards, cover boards, underlayment, and existing membranes.

The membrane panels employed in the membrane composites of the present invention may be prepared by conventional techniques. For example, thermoplastic membrane panels may be formed by the extrusion of thermoplastic compositions into one or more layers that can be laminated into a membrane panel. Thermoset membranes can be formed using known calendering and curing techniques. Alternatively, thermoset membranes can be made by continuous process such as those disclosed in <CIT>.

Once the membrane is formed, the curable hot-melt adhesive can be extruded onto the membrane by using known apparatus such as adhesive coaters. The adhesive can then subsequently be cured by using, for example, UV radiation. The release film can be applied to the adhesive layer, and the membrane can then be subsequently rolled for storage and/or shipment. Advantageously, where the membrane panel is made by using continuous techniques, the process can be supplemented with continuous techniques for applying and curing the adhesive coatings according to embodiments of the present invention to thereby prepare usable membrane composites within a single continuous process.

As generally shown in <FIG>, process <NUM> for preparing a composite membrane according to the present invention generally begins with a step of heating <NUM>, wherein a pressure-sensitive adhesive is heated to a sufficient temperature to allow the adhesive to be applied as a coating within a coating step <NUM>. Within coating step <NUM>, the adhesive is applied to the membrane to form a coating layer. Following formation of the coating, the coating is subjected to a UV-curing step <NUM> where sufficient UV energy is applied to the coating to thereby effect a desirable curing or crosslinking of the adhesive. Once the adhesive has been sufficiently cured by exposure to UV curing step <NUM>, a release member can be applied to the cured coating in a member application step <NUM>. Following application of a member, the composite is wound into a roll at winding step <NUM>.

In one or more embodiments, heating step <NUM> heats the adhesive to a temperature of from about <NUM> to about <NUM>, in other embodiments from about <NUM> to about <NUM>, and in other embodiments from about <NUM> to about <NUM>.

In one or more embodiments, adhesive step <NUM> applies an adhesive to the surface of a membrane to form an adhesive layer of adhesive that has a thickness of at least <NUM> (<NUM> mil), in other embodiments at least <NUM> (<NUM> mil), in other embodiments at least <NUM> (<NUM> mil), and in other embodiments at least <NUM> (<NUM> mil). In one or more embodiments, adhesive step <NUM> applies an adhesive to the surface of a membrane to form a adhesive layer of adhesive that has a thickness of from about <NUM> to about <NUM> (about <NUM> to about <NUM> mil), in other embodiments from about <NUM> to about <NUM> (about <NUM> to about <NUM> mil), and in other embodiments from about <NUM> to about <NUM> (about <NUM> to about <NUM> mil). In one or more embodiments, the adhesive has a uniform thickness such that the thickness of the adhesive at any given point on the surface of the membrane does not vary by more than <NUM> (<NUM> mil), in other embodiments by more than <NUM> (<NUM> mil), and in other embodiments by more than <NUM> (<NUM> mil).

In one or more embodiments, UV curing step <NUM> subjects the adhesive to a UV dosage of from about <NUM> to about <NUM> millijoule/cm<NUM>, in other embodiments from about <NUM> to about <NUM> millijoule/cm<NUM>, in other embodiments from about <NUM> to about <NUM> millijoule/cm<NUM>, in other embodiments from about <NUM> to about <NUM> millijoule/cm<NUM>, and in other embodiments from about <NUM> to about <NUM> millijoule/cm<NUM>. It has advantageously been discovered that the required dosage of energy can be exceeded without having a deleterious impact on the adhesives of the present invention. For example, up to ten times, in other embodiments up to five times, and in other embodiments up to three times the required dosage can be applied to the adhesive composition without having a deleterious impact on the adhesive composition and/or its use in the present invention.

In one or more embodiments, UV curing step <NUM> subjects the adhesive to a UV intensity, which may also be referred to as UV irradiance, of at least <NUM> milliWatts/cm<NUM>, in other embodiments at least <NUM>, and in other embodiments at least <NUM> milliWatts/cm<NUM>. In these or other embodiments, UV curing step <NUM> subjects the adhesive to a UV intensity of from about <NUM> to about <NUM> milliWatts/cm<NUM>, in other embodiments from about <NUM> to about <NUM> milliWatts/cm<NUM>, and in other embodiments from about <NUM> to about <NUM> milliWatts/cm<NUM>. It has advantageously been discovered that the ability to appropriately cure the adhesive compositions of the present invention, and thereby provide a useful pressure-sensitive adhesive for the roofing applications disclosed herein, critically relies on the UV intensity applied to the adhesive. It is believed that the thickness of the adhesives (and therefore the thickness of the pressure-sensitive adhesive layer) employed in the present invention necessitates the application of greater UV intensity.

In one or more embodiments, the energy supplied to the adhesive layer within UV radiation step <NUM> is in the form of UV-C electromagnetic radiation, which can be characterized by a wave length of from about <NUM> to about <NUM>. In one or more embodiments, the UV dosage applied during UV curing step <NUM> is regulated based upon a UV measuring and control system that operates in conjunction with UV curing step <NUM>. According to this system, UV measurements are taken proximate to the surface of the adhesive layer using known equipment such as a UV radiometer. The data from these measurements can be automatically inputted into a central processing system that can process the information relative to desired dosage and/or cure states and automatically send signal to various variable-control systems that can manipulate one or more process parameters. For example, the power supplied to the UV lamps and/or the height at which the UV lamps are positioned above the adhesive layer can be manipulated automatically based upon electronic signal from the central processing unit. In other words, the UV intensity, and therefore the UV dosage, can be adjusted in real time during the manufacturing process.

In one or more embodiments, an exemplary process for preparing the membrane composites of the present invention can be described with reference to <FIG>. Continuous process <NUM> includes a heating step <NUM> where UV curable hot-melt adhesive <NUM> is heated to a desired temperature within a heated tank <NUM>. Adhesive <NUM> is fed into an extrusion device, such as a coater <NUM>, which may include a pump, such as a gear pump <NUM>, and a slot die <NUM>. Within coating step <NUM>, coater <NUM> extrudes adhesive <NUM>, which is in its molten, liquid or flowable state, and deposits a coating layer <NUM> of adhesive <NUM> onto a planar surface <NUM> of membrane <NUM>.

As shown in <FIG>, coating step <NUM> can include a roll-coating operation, where adhesive <NUM> is applied to membrane <NUM> while membrane <NUM> is at least partially wound around a coating mandrel <NUM>. Membrane <NUM> carrying coating layer <NUM> is fed to a crosslinking step <NUM>, where coating layer <NUM> of adhesive <NUM> is subjected to a desired dosage of UV radiation <NUM>, which may be supplied by one or more UV lamps <NUM>. UV lamps <NUM> may include, for example, mercury-type UV lamps or LED UV lamps. As the skilled person appreciates, the desired dosage of UV energy can be supplied to coating <NUM> by adjusting the UV intensity and exposure time. The intensity can be manipulated by the power supplied to the respective lamps and the height (H) that the lamps are placed above the surface of coating <NUM> of adhesive <NUM>. Exposure time can be manipulated based upon the line speed (i.e., the speed at which membrane <NUM> carrying coating layer <NUM> is passed through UV curing step <NUM>).

Following UV curing step <NUM>, release member <NUM> may be applied to upper surface <NUM> of coating layer <NUM> within release member application step <NUM>. As shown in <FIG>, release member <NUM> may be supplied from a mandrel <NUM> and removably mated to upper surface <NUM> through pressure supplied by nip rolls <NUM>. After application of release member <NUM>, the composite product may be wound within winding step <NUM> to provide wound rolls <NUM> of composite products <NUM>.

As suggested above, practice of the present invention provides a lap seam, using the factory-applied pressure-sensitive adhesive described herein, as the sole adhesive, that advantageously outperforms seams prepared using the factory-applied pressure-sensitive adhesives of the prior art. For example, where the factory-applied pressure-sensitive adhesive is solely employed to seam thermoplastic polyolefin membranes (TPO membranes), the seam can achieve a peel strength, per ASTM D-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM> without the use of a primer. Likewise, similar seams can achieve a peel strength, per ASTM D-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM> without the use of a primer. And, similar seams can achieve a peel strength, per ASTM D-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM> without the use of a primer.

In these or other embodiments, where the factory-applied pressure-sensitive adhesive is solely employed to seam thermoplastic polyolefin membranes (TPO membranes) and the contact surface is primed (i.e. the upper surface of the adjoining membrane), the seam can achieve a peel strength, per ASTM D-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM>. Likewise, similar seams can achieve a peel strength, per ASTM D413, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM> when the adjoining surface is primed. And, similar seams can achieve a peel strength, per ASTM D-<NUM>, of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) at <NUM> when the adjoining surface is primed.

Also, where the factory-applied pressure-sensitive adhesive is solely employed to seam thermoplastic polyolefin membranes (TPO membranes), the seam can achieve an adhesive shear strength, per PTR <NUM> (ASTM D-<NUM>), of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM> without the use of a primer. Likewise, similar seams can achieve a peel strength, of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM> without the use of a primer. And, similar seams can achieve a peel strength, of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/m<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM> without the use of a primer.

In these or other embodiments, where the factory-applied pressure-sensitive adhesive is employed to seam thermoplastic polyolefin membranes (TPO membranes) and the contact surface is primed (i.e. the upper surface of the adjoining membrane), the seam can achieve a peel strength, per PTR <NUM> (ASTM D-<NUM>), of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM>. Likewise, similar seams can achieve a peel strength, of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM> when the adjoining surface is primed. And, similar seams can achieve a peel strength, of at least <NUM> kPa (<NUM> lbf/in<NUM>), in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>), and in other embodiments at least <NUM> kPa (<NUM> lbf/in<NUM>) at <NUM> when the adjoining surface is primed.

As suggested above, practice of the present invention provides a lap seam, using the factory-applied pressure-sensitive adhesive described herein, as the sole adhesive, that advantageously outperforms seams prepared using the factory-applied pressure-sensitive adhesives of the prior art. For example, where the factory-applied pressure-sensitive adhesive is solely employed to seam thermoset rubber membranes (EPDM membranes), the seam can achieve a peel strength, per PSTC Standard <NUM> (<NUM>), of at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), in other embodiments at least <NUM> N/m (<NUM> lbf/in), and in other embodiments at least <NUM> N/m (<NUM> lbf/in) without the use of a primer. As a person of ordinary skill in the art will appreciate, the PSTC Standard <NUM> test is performed using an EPDM membrane sheet and adhering the sheet to a similar EPDM sheet as the substrate.

Also, where the factory-applied pressure-sensitive adhesive is solely employed to seam thermoset rubber membranes (EPDM membranes), the seam can achieve an adhesive shear strength, per PSTC Standard <NUM> (<NUM>) at room temperature of at least <NUM> minutes, in other embodiments at least <NUM> minutes, in other embodiments at least <NUM> minutes, and in other embodiments at least <NUM> minutes.

The membrane composites of the present invention can advantageously be applied to a roof surface (also known as roof substrate) by using standard peel-and-stick techniques. For example, the membrane can be unrolled on a roof surface and placed into position. Portions of the membrane are then typically folded back and portions of the release member are removed. The membrane can then subsequently be adhered to the roof surface by using various techniques including the use of rollers and the like to mate the adhesive to the substrate. Where multiple membrane panels are employed, the seams can be secured by using conventional techniques. It has advantageously been discovered that the pressure-sensitive adhesive layer employed in the membranes of the present invention allows the membranes to be adhered to a variety of roofing surfaces. These include, but are not limited to, wood decks, concrete decks, steel decks, faced construction boards, and existing membrane surfaces. In particular embodiments, the membranes of the present invention are adhered, through the cured adhesive layer disclosed herein, to a faced construction board such as, but not limited to, polyisocyanurate insulation boards or cover boards that include facers prepared from polar materials. For example, the adhesives of the present invention provide advantageous adhesion to facers that contain cellulosic materials and/or glass materials. It is believed that the polar nature of the adhesive is highly compatible with the polar nature of these facer materials and/or any adhesives or coatings that may be carried by glass or paper facers. Accordingly, embodiments of the present invention are directed toward a roof deck including a construction board having a cellulosic or glass facer and a membrane secured to the construction board through an at least partially cured polyacrylate adhesive layer in contact with a glass or cellulosic facer of the construction board.

According to aspects of the present invention, a lap seal is advantageously formed by overlapping a portion of adjacent membranes, removing the release member from the lap area portion to expose the pressure-sensitive adhesive, and then mating the pressure-sensitive adhesive to the upper surface of the overlapped, adjacent membrane. In one or more embodiments, the pressure-sensitive adhesive is mated to the adjacent membrane without any additional treatment to the adjacent membrane. For example, a technologically useful lap seam can be formed without the need for priming (either by field application or factory priming) the upper surface of the adjacent membrane that receives the pressure-sensitive adhesive. In other embodiments, the upper surface of the adjacent membrane is field primed. For example, EPDM membranes can be primed with commercially-available primers such as those available from Firestone Building Products, LLC under the tradenames Single Ply Primer, Quickprime Primer, and Low VOC Primer. In other embodiments, seams are prepared with the assistance of a lap sealant (e.g. a rubber-based sealant such as EPDM lap sealant). Useful lap sealants are known in the art as disclosed in <CIT>.

Claim 1:
A roof system comprising:
i. a roof substrate;
ii. a first membrane including first and second opposed planar surfaces, where the first planar surface includes a roof-substrate contacting portion and a lap portion, said first membrane having disposed on said roof-substrate contacting portion and said lap portion a UV-cured adhesive, where said first membrane is adhered to said roof substrate through said adhesive disposed on said roof-substrate contacting portion where the UV-cured adhesive disposed on said first membrane has a substantially consistent degree of cure; and
iii. a second membrane including opposed first and second planar surfaces, where the first planar surface includes a roof-substrate contacting portion and a lap portion, said second membrane having disposed on said roof-substrate contacting portion and said lap portion a UV-cured adhesive, where said second membrane is adhered to said roof substrate through said adhesive disposed on said roof-substrate contacting portion, and where said second membrane is adhered to said first membrane through said adhesive disposed on said lap portion of said second membrane where the UV-cured adhesive disposed on said second membrane has a substantially consistent degree of cure.