Abstract:
A two part adhesive packaging system is provided. The packaging system includes two containers for holding a two-part adhesive. The packaging system further includes a connector having two ports for communicating with the containers. A membrane is adhered overtop the ports to prevent the two-part adhesive from draining from the containers. The membrane is configured to break upon application of a sufficient force thereon, such as by pumping or pushing the two-part adhesive from the containers.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/539,271, filed Sep. 26, 2011. The entire contents of the above application are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present invention relates to an adhesive packaging system, and more particularly to an adhesive packaging system used in an applicator for dispensing an two-part adhesive on a roofing substrate. 
       BACKGROUND 
       [0003]    In many roofing applications, for example in large, flat commercial roof decks, a roofing membrane is used to seal and protect the roof deck from environmental weather conditions. The roofing membrane may be made of various materials, such as polymeric materials including EPDM (ethylene propylene diene M-rubber) or TPO (thermoplastic polyolefin). The roofing membrane is adhered overtop insulation boards or cover boards. The insulation boards are typically secured to the roofing substrate or roof deck via an adhesive composition. A conventional adhesive composition used to adhere the insulation boards to the roof deck, or used to adhere roofing membranes to rigid insulation boards, cover boards, or directly to the roof deck, includes polyurethane. The polyurethane adhesives are oftentimes applied directly onto the roof deck via an applicator system and the insulation boards are then laid onto the roof deck surface. Conventional polyurethane adhesives oftentimes include two separate parts that are mixed by an applicator just prior to being applied onto the surface of the roof deck. The two parts include an isocyanate blend and a simple polyol blend. Upon mixing, the isocyanate blend reacts or crosslinks with the simple polyol blend to form the polyurethane adhesive. 
         [0004]    These conventional two-part polyurethane adhesives must be packaged into separate containers to prevent mixing of the adhesive parts prior to application. In certain configurations, the adhesive parts are packaged into a single system having divided, separately sealed sides for storing the adhesive parts. Upon removal of a port cap, the adhesive sides communicate with an attached nozzle. However, if the nozzle is attached and then stored, it is possible for the adhesive parts to drain into the nozzle prior to application, crosslink, and plug the nozzle or the package with cured polyurethane. Therefore, there is a need in the art to provide an adhesive packaging system that prevents unwanted mixing of the adhesive parts prior to application on a substrate, but after the attachment of the mixing nozzle. 
       SUMMARY 
       [0005]    A two part adhesive packaging system is provided. The packaging system includes two containers for holding a two-part adhesive. The packaging system further includes a connector having two ports for communicating with the containers. A membrane is adhered overtop the ports to prevent the two-part adhesive from draining from the containers. The membrane is configured to break upon application of a sufficient force thereon, such as by pumping or pushing the two-part adhesive from the containers. 
     
    
     
       DRAWING DESCRIPTION 
         [0006]      FIG. 1  is a side view of a packaging system according to the principles of the present invention; 
           [0007]      FIG. 2  is a top view of the packaging system shown in  FIG. 1  with a cap removed; 
           [0008]      FIG. 3  is a cross-section view of the packaging system viewed in the direction of arrow  3 - 3  shown in  FIG. 2 ; 
           [0009]      FIG. 4  is a perspective view of the packaging system with a mixing nozzle shown in an exemplary applicator device; 
           [0010]      FIG. 5  is a top view of an alternate packaging system according to the principles of the present invention; and 
           [0011]      FIG. 6  is a cross-section view of the packaging system viewed in the direction of arrow  3 - 3  shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0013]    Referring to  FIG. 1 , a packaging system or cartridge for a two-part adhesive is generally indicated by reference number  10 . The packaging system  10  is configured to store two separate components or parts of a two-part adhesive compound. For example, the two-part adhesive is a polyurethane adhesive for use on roofing substrates. Prior to mixing, the adhesive is comprised of two separate parts including an isocyanate blend and a polyol blend. The packaging system  10  includes an “A” side container  10 A attached to a “B” side container  10 B. Each of the containers  10 A and  10 B define a storage space  12 A and  12 B, respectively. Each space  12 A and  12 B stores a different part of the two-part adhesive compound. The spaces  12 A and  12 B are separated from one another by an interior wall  14  in order to prevent mixing of the parts prior to application of the adhesive on a substrate. In one example, the containers  10 A and  10 B are each generally cylindrical and are formed from a single molded body, though it should be appreciated that the containers  10 A and  10 B may have other shapes and be made from separately formed, attached components without departing from the scope of the present invention. 
         [0014]    The packaging system  10  includes an outlet  16  located on an end of the containers  10 A and  10 B. The outlet  16  includes an “A” side port  18 A and a “B” side port  18 B that communicate with the spaces  12 A and  12 B, respectively. The ports  18 A and  18 B are configured to allow the parts of the adhesive compound stored in the packaging system  10  to be pumped, pushed, or otherwise forced out of the containers  10 A and  10 B. For example, where the adhesive compound is pushed out of the packaging system  10 , the packaging system  10  includes a piston  25 A disposed in an open end of the container  10 A and a piston  25 B disposed in an end of the container  10 B. The pistons  25 A and  25 B are in contact with the contents of the containers  10 A and  10 B, respectively. The pistons  25 A and  25 B may be separate pieces or connected. Pushing the pistons  25 A and  25 B forces the adhesive compound out of the packaging system  10  as described below. 
         [0015]    The ports  18 A and  18 B communicate from the spaces  12 A and  12 B, respectively, through a connector  20 . The connector  20  is a cylindrical extension located the end of the containers  10 A and  10 B opposite the pistons  25 A and  25 B. The connector  20  includes a flat or planar top surface  22  and a threaded side surface  24 . It should be appreciated that the side surface  24  may include other kinds of connection features in addition to or in place of threads, such as lips or grooves, without departing from the scope of the present invention. The planar top surface  22  is preferably completely flat. A membrane  26  is disposed overtop the flat top surface  22 . The membrane  26  is preferably a light gauge foil, a plastic coated foil, or laminates of paper, foil, and/or plastics. The membrane  26  is adhered to the flat top surface  22  by an adhesive disposed circumferentially around each of the ports  18 A and  18 B. A cap  28  is removably attached to the connector  20  via mating threads (not shown) complementary to the threaded side surface  24 . Alternatively a membrane constructed of foil or coated paper or foil may simply be held in place by crimping the membrane onto the threaded sides of connector  20  by the attachment of the cap  28 . Alternatively a heat-shrink plastic or UV activated shrinkable plastic may be used to secure the membrane over the connector  20 . The cap  28  securely fits overtop the connector  20  and the membrane  26  to protect the membrane  26  during shipment or storage of the packaging system  10 . The inside of the cap  28  is preferably a flat surface that seats firmly against the membrane  26  to prevent premature rupture of the membrane  26  during shipping and handling. 
         [0016]    Turning to  FIG. 4 , prior to application of the adhesive, the cap  28  is removed from the adhesive system  10  thereby exposing the connector  20  and the membrane  26 . An applicator nozzle  30  is then attached to the connector  20  via mating threads (not shown) complementary to the threaded side surface  24 . The applicator nozzle  30  is an extended member that mixes the “A” side fluid with the “B” side fluid. The nozzle  30  is disposable and is preferably an element, static mixing nozzle, though it should be appreciated that other types and grades of nozzles may be employed without departing from the scope of the present invention. 
         [0017]    The packaging system  10  and attached connector  20  are then loaded into an applicator device  32 . An exemplary applicator device is disclosed in commonly owned U.S. Pat. No. 7,056,556, hereby incorporated by reference. It should be appreciated that any other number of applicator devices such as pneumatic single-bead applicators, battery powered single-bead applicators, manual applicators, among other devices may be employed without departing from the scope of the present invention. Contractors often are required to pre-attach the mixing nozzle  30  to the packaging system  10  to efficiently stage a job. Once pre-staged, job interruptions such as rainstorms can occur. Isocyanates, commonly used in 2-part polyurethane adhesives are moisture sensitive and rainwater dripping into a mixing nozzle can cause a chemical reaction to occur. Likewise, pre-staged jobs left overnight can suffer from dew forming in the mixing nozzle and causing reaction of the isocyanate. In addition, contractors often load the cartridges into equipment and then must pause while they wait for obstructions to be removed from the path of intended adhesive application. This is especially an issue for newer low-viscosity adhesive formulas for applications such as membrane attachment that can be problematic due to how fast the low-viscosity adhesives run into the nozzle  30  when loaded into the applicator  32 . However, the membrane  26  prevents the adhesive parts from draining through the ports  18 A and  18 B when stored without the cap  28  thereby preventing the adhesive parts from mixing prematurely in the applicator  20  or nozzle  30 . Some adhesives are formulated with substantially different viscosities in the polyol and isocyanate portions. In this case the lower viscosity portion tends to gravity feed into the mixing nozzle prior to the mechanical operation of the equipment causing an off-ratio adhesive mix during the initial dispense. The off-ratio adhesive may not perform as expected. The packaging system  10  may then be installed and stored in the device  32  without the applicator  20  becoming blocked due to the adhesive components crosslinking in the applicator  20  or without off-ratio initial dispenses or without messy adhesive draining through the mixing tip. 
         [0018]    To apply the adhesive, the device  32  pumps, pushes, or otherwise forces the components out of the packaging system  10 . The components create a pressure on the membrane  26  which ruptures or breaks the membrane  26 , thereby allowing the components to enter the applicator  20 . The membrane  26  has a pressure breaking point that allows the membrane  26  to burst before the pressure in the containers  10 A and  10 B builds such that the components leak out of the back sides of the containers  10 A and  10 B. The applicator  20  mixes the A and B side components and the combined fluid exits the applicator  20  and is dispensed in the form of elongated beads on a substrate  34 . The mixed compound then cures and forms an adhesive. 
         [0019]    Turning to  FIGS. 5 and 6 , and alternate embodiment of a packaging system is generally indicated by reference number  10 ′. The packaging system  10 ′ is similar to the packaging system  10  and like components are indicated by like reference numbers. However, the packaging system  10 ′ includes a radial flange  40  disposed along the circumference of the connector  20 . The radial flange  40  surrounds the ports  18 A and  18 B. A linear flange  42  is disposed between the ports  18 A and  18 B thereby bifurcating the radial flange  40 . The membrane  26  is disposed overtop the radial flange  40  and the linear flange  42 . The membrane  26  is adhered to the radial flange  40  and the linear flange  42  by an adhesive disposed on the radial flange  40  and the linear flange  42 . The packaging system  10 ′ operates in a manner similar to the packaging system  10 . 
         [0020]    The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.