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 mixing nozzle is attachable to the containers. The mixing nozzle includes a membrane disposed therein. 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 TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/903,711 filed Nov. 13, 2013. The disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present invention relates to an adhesive packaging system used in dispensing a two-part adhesive onto a roofing substrate, and more particularly to an adhesive or sealant packaging system having a protective membrane to prevent premature mixing of the two-part adhesive or sealant. 
       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 polyol blend. Upon mixing, the isocyanate blend reacts or crosslinks with the 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. One solution is to place a membrane overtop the port but underneath the port cap. However, this membrane may become ruptured or pierced during shipping and handling or during removal of the port cap, thus defeating the purpose of the membrane. In other cartridge configurations, plugs are inserted into the ports or molded over the ports to seal the contents of the cartridge during storage and transportation. Prior to application the plugs are removed and the mixing nozzle is attached. Therefore is also possible for adhesive components to prematurely dispense and mix if the cartridge and mixing nozzle are stored with the plugs removed. 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, and allows for the use of port caps, port plugs, or both without rupturing the membrane. 
       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 removable cap is placed overtop the two ports. In one embodiment, plugs (not shown) are inserted into the two ports. When the cap is removed, a membrane is disposed overtop the ports to prevent the two-part adhesive from draining from the containers. The membrane may be attached to a mixing nozzle that replaces the cap or alternatively may be attached overtop the ports once the cap has been removed. 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. 
         [0006]    For example, a system for storing and mixing a first part and a second part of a two-part adhesive includes a cartridge having a first container that defines a first space for storing the first part of the adhesive, a second container that defines a second space for storing the second part of the adhesive and connected to the first container, a connector connected to the first container and the second container, a first port disposed in the connector and in communication with the first space, and a second port disposed in the connector and in communication with the second space. A mixing nozzle having an attachment portion is removably connected to the connector of the cartridge. The mixing nozzle has a mixing portion for mixing the first part with the second part and a membrane disposed between the attachment portion and the mixing portion. 
         [0007]    In one aspect, the membrane is ruptured by the first part or the second part of the adhesive when the first part or the second part of the adhesive is forced out of the first space and the second space. 
         [0008]    In another aspect, the membrane includes a ring and a membrane cover connected to the ring. 
         [0009]    In another aspect, the membrane cover is adhered to an inner diameter of the ring. 
         [0010]    In another aspect, the membrane cover is adhered to a side of the ring and has a diameter approximately equal to an outer diameter of the ring. 
         [0011]    In another aspect, the ring has an inner diameter that is greater than the outer diameter of the connector and has an axial thickness that allows the membrane cover to sit flush with a planar surface of the connector. 
         [0012]    In another aspect, the attachment portion includes a connection feature disposed on an inner surface that engages a connection feature on the connector, and wherein the ring has an outer diameter that fits between the connection feature of the attachment portion. 
         [0013]    In another aspect, the mixing portion includes an inner surface that defines an annular groove, and the ring is disposed within the annular groove. 
         [0014]    In another aspect, the annular groove is defined by an axial surface and a radial surface. 
         [0015]    In another aspect, the ring is made from a rigid material and the membrane cover is made from a rupturable material. 
         [0016]    In another aspect, the membrane is disc shaped and adhered along a periphery of the inner surface of the mixing portion and covers the first port and the second port. 
         [0017]    In another aspect, a first piston is disposed in the first space and a second piston is disposed in the second space, and wherein the pistons move to push the first part and the second part out through the first port and the second port to rupture the membrane and enter the mixing portion. 
         [0018]    In another aspect, the first piston is in contact with the first part and the second piston is in contact with the second part. 
         [0019]    In another aspect, the membrane is attached to an outside portion of the cartridge, and wherein the membrane is folded overtop the connector to cover the first and second ports between the connector and the mixing nozzle. 
         [0020]    Further features, aspects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature. 
         [0021]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         [0022]      FIG. 1  is a side view of a packaging system according to the principles of the present invention; 
         [0023]      FIG. 2  is a top view of the packaging system shown in  FIG. 1  with a cap removed; 
         [0024]      FIG. 3  is a perspective view of the packaging system with a mixing nozzle shown in an exemplary applicator device; 
         [0025]      FIG. 4  is a cross-section view of the mixing nozzle shown shown in  FIG. 3 ; 
         [0026]      FIG. 5A  is an end view of a membrane used in the mixing nozzle; 
         [0027]      FIG. 5B  is a cross section view of the membrane viewed in the direction of arrow  5 B- 5 B shown in  FIG. 5A ; 
         [0028]      FIG. 6A  is an end view of another membrane used in the mixing nozzle; 
         [0029]      FIG. 6B  is a cross section view of the membrane viewed in the direction of arrow  6 B- 6 B shown in  FIG. 6A ; 
         [0030]      FIG. 7A  is a side view of an alternate packaging system according to the principles of the present invention; 
         [0031]      FIG. 7B  is a side view of the alternate packaging system with a membrane in a cover position; and 
         [0032]      FIG. 7C  is a side view of the alternate packaging system with an attached mixing nozzle. 
     
    
     DETAILED DESCRIPTION 
       [0033]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0034]    Referring to  FIGS. 1 and 2 , a packaging system or cartridge for a two-part adhesive illustrated and 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. 
         [0035]    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. 
         [0036]    The ports  18 A and  18 B communicate from the spaces  12 A and  12 B, respectively, through a base  19  and a connector  20 . In one embodiment, plugs (not shown) are removably inserted into the two ports  18 A and  18 B. The base  19  is a square or rectangular portion disposed overtop an end of the containers  10 A and  10 B opposite the pistons  25 A and  25 B. The connector  20  is a cylindrical extension that 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 cap  28  is removably attached to the connector  20  via mating threads (not shown) complementary to the threaded side surface  24 . The cap  28  securely fits overtop the connector  20  to cover the ports  18 A and  18 B during shipment, storage, etc. 
         [0037]    Turning to  FIGS. 3 and 4 , prior to application of the adhesive, the cap  28  (or plugs) is removed from the adhesive system  10  thereby exposing the connector  20 . An applicator or mixing nozzle  30  is then attached to the connector  20  via mating threads  31  complementary to the threaded side surface  24 . The mixing nozzle  30  is an extended member that mixes the “A” side fluid with the “B” side fluid. The mixing nozzle  30  is disposable and is preferably an element, static mixing nozzle, though it should be appreciated that other types and grades of mixers may be employed without departing from the scope of the present invention. 
         [0038]    The packaging system  10  and attached mixing nozzle  30  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 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 mixing nozzle  30  when loaded into the applicator  32 . In order to prevent premature mixing or spills, the mixing nozzle  30  includes a membrane  34 . For example, with reference to  FIG. 4 , the mixing nozzle  30  includes a first end or attachment portion  30 A and an opposite, second end or nozzle  30 B. The first end  30 A includes the internal threads  31  that are complementary with the threads  24  on the connector  20 . Between the first end  30 A and the second end  30 B is an extended tube portion or mixing portion  36 . A static mixing element or a helical mixing member  38  is preferably disposed within the tube portion  36 . The mixing member  38  aids in the mixing of the A part and B part of the polyurethane prior to dispensing from the second end  30 B. The membrane  34  is preferably disposed between the attachment portion  30 A and the tube portion  36 , and preferably between the threads  31  and the mixing member  38 . For example, the tube portion  36  may include an annular groove  40  formed in an inner surface  41  of the tubular portion  36 . The annular groove  40  receives the membrane  34  therein. In the example provided, the annular groove  40  is defined by an annular surface  41 A and a step, radial surface  41 B. 
         [0039]    Turning to  FIGS. 5A and 5B , the membrane  34  preferably includes a support ring  42  and a membrane cover  44  connected to an inner diameter of the support ring  42 . The support ring  42  is preferably a rigid material such as a plastic, metal, or paper/cardboard. The support ring  42  is disposed within the groove  40  and contacts the step surface  40 B to prevent the membrane  34  from moving axially along the length of the tubular portion  36  of the mixing nozzle  30 . The support ring  42  dimensions are functions of the inner diameter of the threads  31 , the size of the annular groove  40 , and the outer diameter and a height ‘h’ of the connector  20  (shown in  FIG. 7A ). For example, the support ring  42  preferably has an outer diameter that fits inside or between consecutive threads  31  so that the support ring  42  is seated within the annular groove  40 . The support ring  42  also has an inner diameter and axial thickness that is greater than the outer diameter of the connector  20  and has a thickness that allows the membrane cover  44  to sit flush with the planar surface of the connector  20 . In one example, the outer diameter of the connector  20  is 0.675″, the height h of the connector  20  is 0.225″, the inner diameter of the thread is 0.828″, the inner diameter of the annular groove is 0.658″, and therefore the support ring  42  has an inner diameter of 0.68″, an outer diameter of 0.8″, and a thickness of 0.23″. The membrane cover  44  is preferably a light gauge foil, a plastic coated foil, or laminates of paper, foil, and/or plastics that are adhered to the inner radius of the support ring  42 . Alternatively, the membrane cover  44  is adhered to a side or end surface of the support ring  42 , as shown in  FIG. 5B  using dashed lines, and has a diameter substantially equal to the outer diameter of the support ring  42 . In one example, the membrane cover  44  is comprised of aluminum foil having a thickness of 1.5 mil (0.038 mm) and ruptures at approximately 33 psi. In another example, the membrane cover  44  is comprised of aluminum foil having a thickness of 2.5 mil (0.064 mm) and ruptures at approximately 71 psi. However, if the aluminum foil is too thin, the membrane cover  44  can rupture prematurely when the mixing nozzle  30  is attached to the connector  20 . For example, a membrane cover  44  comprised of aluminum foil having a thickness of 1.0 mil (0.025 mm) ruptures at approximately 11.5 psi, a pressure too low for the intended use. Turning to  FIGS. 6A and 6B , an alternate membrane  34 ′ is shown. The membrane  34 ′ comprises a disc shaped membrane cover  44 ′. The membrane cover  44 ′ is a light gauge foil, a plastic coated foil, or laminates of paper, foil, and/or plastics that is adhered along an outer periphery to the inner surface  41  of the tubular portion  36  within the groove  40 . 
         [0040]    Returning to  FIGS. 1-4 , the membrane  34  prevents the adhesive parts from draining through the ports  18 A and  18 B when stored without the cap  28  or plugs thereby preventing the adhesive parts from mixing prematurely in the applicator  20  or mixing nozzle  30 . When pressure below a threshold or breaking or rupture pressure is applied to the membrane  34 , the support ring  42  seals against the step portion  40 B thereby preventing fluid from exiting the ports  18 A and  18 B. 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. Using the mixing nozzle  30  with the membrane  34 , the packaging system  10  may then be installed and stored in the device  32  without the mixing nozzle  30  becoming blocked due to the adhesive components crosslinking in the mixing nozzle  30  or without off-ratio initial dispenses or without messy adhesive draining through the mixing nozzle  30 . 
         [0041]    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 cover  44  greater than the threshold or breaking pressure which ruptures or breaks the membrane cover  44 , thereby allowing the components to enter the helical mixing member  38 . The threshold or breaking pressure is set to allow the membrane cover  44  to rupture 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 helical mixing member  38  mixes the A and B side components and the combined fluid exits the mixing nozzle  30  at the second end  30 B and is dispensed in the form of elongated beads on a substrate  50 . The mixed compound then cures and forms an adhesive. 
         [0042]    Turning to  FIGS. 7A and 7B , 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 membrane flap  52  attached to the packaging system  10 ′. The membrane flap  52  is preferably a resilient, flexible material such as a foil, a plastic coated foil, or laminates of paper, foil, and/or plastics. The membrane flap  52  is preferably adhered or crimped to the base  19  between the containers  10 A and  10 B and the connector  20 . When the cap  28  is removed, the membrane flap  52  is folded overtop the connector  20  to cover the ports  18 A and  18 B, as seen in  FIG. 7B . The membrane flap  52  is sufficiently large enough to cover the ports  18 A and  18 B when folded over the connector  20  and may have various shapes. The mixing nozzle  30  is then attached to the connector  20  overtop the membrane flap  52 , either by threads or a snap fit connection, shown in  FIG. 7C . The membrane flap  52  seals the ports  18 A and  18 B. 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  52  greater than a threshold or breaking pressure which ruptures or breaks the membrane  52 , thereby allowing the components to enter the helical mixing member  38 . 
         [0043]    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.