Abstract:
A batt of acoustical/thermal insulation for use in insulating appliances, compressors, machines and the like is disclosed. The batt comprises a fiberglass blanket and a release liner assembly. The liner assembly features a carrier sheet for supporting layers or coatings of adhesive on opposite broad surfaces thereof. One adhesive coated surface of the carrier sheet is releasably adhesively attached to a conventional release liner which is coated with an adhesive release agent. The other adhesively coated surface is joined to exposed fibers of a surface portion of the fiberglass blanket while the adhesive coating is in a heated, uncured, liquid state so as to immerse surface fibbers of the blanket in the adhesive. The carrier sheet adds stability to the resulting laminate structure and prevents surface fibers from being torn from the blanket when the release liner is removed from the carrier at the time of placement of the batt in service. A method for forming the batt is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a fiberglass blanket having an adhesively attached release liner assembly and method for making the same. An important aspect of this invention is the replacement of a carrier sheet in the release liner assembly for carrying adhesive coatings on opposite surfaces thereof for joinder with a release liner and with surface fibers of the fiberglass blanket. Another important aspect of this invention is the application to either the surface fibers of the fiberglass blanket or to a surface of the carrier sheet of an adhesive coating in an uncured liquid state and the subsequent joinder of the blanket to the carrier sheet while the adhesive coating is in the liquid state such that surface fibers of the blanket are thoroughly coated with the adhesive. 
     It has long been known in the prior art to adhesively join a fiberglass insulation blanket directly to a sheet of silicone coated release paper. A difficulty encountered with this prior art process and the resulting prior art product is that when the release liner is peeled away from the surface of the blanket at the time it is being placed in service as a thermal or acoustical insulator, surface fibers are often torn away from the blanket as well. Another difficulty encountered has to do with adhesively joining the blanket to the release liner when the adhesive is in a semi-liquidous, plastic-like state because the adhesive does not thoroughly coat surface fibers of the blanket, whereby the tensil strength or “peel” strength of the resulting assembly can be less than a desirable or even suitable level. 
     By means of our invention, these and other disadvantages encountered using prior art fiberglass blankets with adhesively joined release liners are substantially overcome. 
     SUMMARY OF THE INVENTION 
     It is an object of our invention to provide a novel batt of acoustical/thermal insulation including a fiberglass blanket and an adhesively joined release liner assembly. 
     It is a further object of our invention to provide a novel method for making a batt of insulation. 
     It is yet another object of our invention to provide a batt of insulation including a fiberglass blanket and a release liner assembly wherein the assembly includes a carrier sheet for supporting a layer of adhesive used to join the blanket to the assembly. 
     It is also an object of our invention to provide a batt of insulation including a fiberlass blanket and a release liner assembly wherein the former is adhesively joined to the latter by an adhesive coating while the coating is in a heated, uncured liquid state. 
     Briefly, in accordance with our invention there is provided an improved acoustical and thermal insulation laminate of the type which conventionally includes a fiberglass blanket and a release liner sheet. The improvement comprises a carrier sheet for carrying adhesive coatings on opposite broad surfaces thereof. A first of the coatings is sandwiched between the carrier sheet and the fiberglass blanket and a second of the coatings is sandwiched between the carrier sheet and the release liner sheet. 
     An additional feature of our invention is application of at least one of the adhesive coatings to either the carrier sheet or the fiberglass blanket while in a heated, uncured liquid state followed by adhesively joining the carrier sheet to the fiberglass blanket while the adhesive coating therebetween is still in a liquid state such that surface fibers of the blanket can be thoroughly coated with the adhesive. 
     These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and attached drawings upon which, by way of example, only certain preferred and other important embodiments of our invention are described and illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a cross-sectional edge view of a fiberglass blanket having a release liner assembly adhesively attached thereto, thus illustrating a preferred embodiment of our invention. 
     FIG. 2 shows a perspective view of a release liner assembly partially rolled for transportation and/or storage. 
     FIG. 3 shows schematically, a system for assembling the release liner assembly of FIG.  2 . 
     FIG. 4 shows an enlarged side elevation view of a fragment of the assembly system of FIG. 3, illustrating a work station for applying a liquid adhesive coating onto a surface of an adhesive carrier sheet. 
     FIG. 5 shows a top plan view of the work station of FIG. 4 with the overlying carrier sheet of the release liner assembly being removed. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing figures and, specifically, to FIG. 1, there is shown, in a preferred embodiment of our invention, a batt of thermal and/or acoustical insulation, generally designated  10 . The batt  10  includes a fiberglass blanket  12  having a conventional backing  14  such as may be formed of fiberglass, aluminum foil scrim kraft (also known as FSK) or other suitable and well known materials customarily used to cover a broad surface of a fiberglass blanket to protect what would otherwise be an exposed surface of the blanket during handling. The backing  14  is joined to a first broad surface of the fiberglass blanket  12  by a suitable layer  16  of adhesive in a conventional and well known manner. 
     Now, in accordance with our invention, and with additional reference to FIG. 2, a release liner assembly  17  (See FIG. 2) is formed for joinder to a second broad surface of the fiberglass blanket  12  which includes a carrier sheet  18  for carrying pressure sensitive adhesive layers  20  and  22  on opposite broad surfaces thereof and a release liner sheet  24 . The carrier sheet  18  should be flexible and may be constructed of suitable plastic such as that sold by the DuPont Company under the trademark MYLAR. It may also be in the form of a woven fabric or textile, FSK, or even paper, provided the paper is sufficiently thick and durable so as not to tear when the release liner sheet  24  is removed from the adhesive containing carrier sheet  18 , as later more fully explained. The release liner  24  is conventional and may be formed of paper or a suitable paper-like plastic which contains a suitable adhesive release agent on the broad surface of the liner  24  which engages the adhesive layer  22 . The release agent is preferably silicone, although other suitable materials such as Teflon could be used, provided cost is not a major consideration. 
     The release liner assembly  17  is shown in FIG. 2 prior to being applied to the fiberglass blanket  12 ,  14  of FIG. 1 to form the batt  10  of the latter mentioned figure. The release liner assembly  17  is typically far less bulky than the fiberglass blanket  12 ,  14  and can be gathered tightly into a relatively dense roll as shown in FIG. 2 for convenient storage and/or transportation prior to being added to the more bulky fiberglass blanket. Note in FIG. 2 the carrier  18 , the adhesive layer  22  and the release liner  24 . In this example, the adhesive layer  22  is applied in two spaced apart strips  28  and  30  to form a central gap  32  in the adhesive layer which extends longitudinally of the assembly  17 . The liner  24  is slit longitudinally along a slit line  34  which extends over and along the approximate center of the gap  32  to form two liner strips  36  and  38 . Inner edge portions of the liner strips  36  and  38  thus extend over the gap  32  to meet along the slit line  34 . As a result, the liner strips  36  and  38  can readily be gripped by hand over the gap  32  and peeled off of the adhesive strips  28  and  30  outwardly away from the slit line  34  when that action becomes necessary to expose the adhesive layer  22  following assembly of the batt  10  and at the time it is being placed in service. 
     Referring now in addition to FIG. 3 there is shown, schematically, a mechanical assembly line, generally designated  39  for forming the release liner assembly  17  of FIG.  2 . Thereafter, the same or a different and generally similar assembly line can be used to join the completed assembly  17  to the fiberglass blanket  12 ,  14  of FIG. 1 to form the batt  10  of the latter mentioned figure. In forming the release liner assembly  17 , a frame  40  is provided containing a roller  42  mounted on standards  43  over a table  44 . A roll of the release liner  24  is mounted on the roller  42  so that the liner can be unrolled downwardly from left to right as viewed, through a slitter assembly containing a hardened steel roller  56  upon which rolls a conventional cutting roller  58  and, thence, through a pair of guide rollers  48  and, thereafter, along the table  44 . A roller  50  located under the table  44 , contains a roll of the carrier  18 . The carrier  18  is unrolled from right to left as viewed toward and around an end roller  54 , thence from left to right as viewed along the top of the table  44  and through the rollers  48  under the release liner  24 . 
     Referring now also to FIGS. 4-5 and located between the roller  50  and the roller  54  of FIG. 3 is positioned a work station for applying an uncured adhesive in a liquid state to a broad surface of the carrier  18  which will ultimately be adhesively joined to an opposing broad surface of the slit release liner  24  by the rollers  48 . The subject work station includes a first roller  60  mounted over a vat  62  containing an uncured adhesive  64  in a liquid state so that, as the roller  60  turns, a lower portion thereof travels through the uncured liquid adhesive  64  in the vat. (See particularly FIG.  4 ). As the roller  60  continues to turn with liquid adhesive applied thereto, it encounters a second roller  66  mounted above it which rotates in the opposite direction such that the second roller picks up liquid adhesive from the first roller and wipes it onto the underside of the carrier  18  traveling over it toward the roller  54 . A semicircular metal bracket  68  overlies a central portion of the roller  66  to prevent adhesive from being applied to a longitudinally extending central strip of the carrier  18 , thereby forming the gap  32  between the two side strips  28  and  30  of the adhesive as shown in FIG.  2 . The bracket  68  is welded to a support arm  70  extending from the far side of the frame  40 . Accordingly, as the carrier  18  rounds the end roller  54  it contains the liquidous adhesive on the broad surface thereof to be joined to the liner  24  by the rollers  48 . 
     After joinder of the carrier  18  to the liquid adhesive containing surface of the release liner  24  to form the release liner assembly  17 , the latter is pulled through an oven  72  to cure the adhesive layer  22  as shown in FIG.  2 . The adhesive layer  22  can range in thickness from about ½ mil up to about 8 to 10 mils. Typically, an adhesive layer thickness of about 4 mils will be satisfactory for most applications. The oven  72  should be heated to a temperature of between about 200 to 300 degrees F. and the release liner assembly  17  should be run at a speed through the oven which will take any portion thereof from about 2 to 5 minutes to pass through. The minimum time of passage of the assembly  17  through the oven  72  necessary to cure the adhesive will depend, in large measure, on the thickness of the adhesive layer  22 . After passage through the oven  72 , the liner assembly  17  containing the now cured adhesive layer  22  is rolled tightly about a driven roller  74 . In the alternative, the adhesive layer  22  of the assembly  17  could be air cured for about  24  to  96  hours after the assembly is formed into a roll, depending upon thickness of the layer and ambient temperature and humidity conditions, in which event the oven  72  would either be by-passed by the assembly  17  or, otherwise turned off. 
     Once the assembly  17  has been formed it can be run on a similar assembly line to add the adhesive layer  20  in a liquid state to the opposite surface of the carrier  18  and then be joined to the fiberglass blanket  12 ,  14  to form the batt  10  as shown in FIG.  1 . The joinder of the fiberglass blanket  12 ,  14  to the adhesive layer  20  of the carrier  18  while the adhesive is in a liquid state is important because this permits glass fibers at the surface of the blanket being joined with the carrier  18  to be relatively deeply immersed in and, thus, be more fully coated with adhesive than would otherwise be the case where the layer  20  is in a more a plastic or semi-liquidous state at the time of joinder with the blanket. Types of adhesive that are suitable for the layer  20  and which may also be used for the layer  22  include hot melt adhesives having a rubber, acrylic, water or solvent base. Such hot melt adhesives must typically be heated and applied at a temperature above about 120 degrees F., which is the temperature at and below which the adhesive becomes tacky. We recommend heating such an adhesive to about 140 degrees F. to be assured that it will remain liquidous on the surface of the carrier  18  until joined to the fiberglass  12  in an assembly line process. 
     The present example illustrates applying the layer  22  of adhesive to the carrier  18  before joinder of the release liner  24  to the carrier  18 . In the alternative, the adhesive layer  22  could be applied directly to a broad surface of the release liner  24  before joinder of that surface to the carrier  18 . We prefer applying the liquidous adhesive to the carrier  18  rather than to the liner  24  because the liquid tends to bead on the latter rather than form a smooth coating as it does on the former. Similarly, the adhesive layer  20  can either be applied in a liquid state to the carrier  18  before joinder to the fiberglass blanket  12  or the liquid adhesive layer  20  can be applied directly to the exposed broad surface of the fiberglass blanket  12  before joinder with the opposing broad surface of the carrier  18 . The application of side-by-side strips of adhesive such as at  28  and  30  in FIG. 2 to either the release liner  24  or the carrier  18  before joinder of one with the other so as to form a longitudinally extending gap  32  between the strips over which inner edges of the release liner  24  overlap and abutt along the central slit  34  is optional. It provides convenience in handling of the batt  10  during installation for purposes of thermal and/or acoustical insulation in removing the release liner  24  for attachment of the tacky adhesive layer  22  to an appliance on machine to be shielded by the batt. The use of the carrier  18  for supporting the adhesive layers  20  and  22  and the application of the adhesive layer  20  in a liquid state to immerse surface fibers of the fiberglass blanket  12  therein constitute critical features of this invention. 
     To complete the description of the preferred embodiment of our invention we recommend the following: Release liner  18  by International Paper, Akrosil Division, 206 Garfield Avenue, product designation, SBL 42 SC SILOX G1H/0 or SBL 3.2 SC SILOX G21/0 or by Griff and Associates, 7900 N. Radcliffe Street, Bldg. 106, Bristol, Pa. 19007, product designation, 4003 Release Paper; Pressure Sensitive Adhesive for layer  20  and, if desired, layer  22  by Air Products and Chemicals, Inc., 7201 Hamilton Blvd., Allentown, Pa. 18195-1501, product designation, Flexcryl LC.18 or 560H or by H. B. Fuller Company, Corporate R&amp;D Facility, 3450 LaBore Road, Vadnais Heights, Minn. 55110, product designation, WB-3236 Y EN, WB-3236 Y B or WB-0912; Carrier  18  by Transilwrap Company, Inc., 2820 N. Paulina Street, Suite 100, Chicago, Ill. 60657, product designation, ½ mil clear polyester film or ½ mil clear DuPont film or by Douglas Hanson Company, Inc., P.O. Box 207, Hammond, Wis. 54015, product designation, 0.0005″ PET film; Fiberglass Insulation  12  by John Manville, P.O. Box 5108, Denver, Colo. 80217-5108, product designation, Microlite, Tufskin, EOM, or SG-30 or by Owens Corning, Fiberglass Tower, T/22, Toledo, Ohio 43659, product designation, Thermomat, HV-24 or EA-30. 
     The use of a carrier such as shown at  18  to carry pressure sensitive adhesive thereon to join the fiberglass blanket  12 , such as shown at  20 , adds significant tensile strength to the adhesive layer over that which would be present without the carrier and is believed to be novel when used with fiberglass. Also use of the carrier  18  for supporting the adhesive layer  20  aids in preventing glass fibers from being torn from the blanket  12  upon removal of the release liner  24  as where the release liner is adhesively adhered directly to the fiberglass blanket in accordance with prior art techniques. 
     In an alternative embodiment of our invention, a release liner assembly is formed for application to a fiberglass blanket in the following manner. A roll or sheet of release liner is provided which contains a conventional adhesive release agent such as a silicone film on both broad surfaces thereof. A roll or sheet of carrier for supporting an adhesive layer on both broad surfaces thereof is also provided. Next, a first coating of a curable adhesive is applied to either a first broad surface of the carrier or to a first broad surface of the release liner, after which the carrier and release liner are adhesively joined. A second coating of a curable adhesive is heated and applied in a liquid state to a second broad surface of the carrier. The adhesive coatings are cured and the resulting relatively thin release liner assembly is gathered into a roll wherein the second coating of adhesive on the second surface of the carrier is applied against an exposed, release agent containing broad surface of the release liner. 
     Thereafter, the relatively thin release liner assembly can be stored and/or shipped to a remote location for assembly with a relatively bulky fiberglass blanket near a point of sale. At the remote location the roll of release liner assembly can be unrolled to expose the second adhesive layer on the carrier and the second layer, along with the first layer, can be reheated to reliquify the second layer for joining a roll or sheet of fiberglass to the exposed and reliquified layer of adhesive on the carrier to form a bat or insulation. Thereafter, the adhesive layers of the batt can be either recured either by air or in an over. In this manner, substantial transportion costs can be saved by forming the relatively thin release liner assembly at one location for shipment to another location for later joinder with the relatively bulky fiberglass blanket at the latter location which would presumably be closer to the point of sale and/or use than the original location where the release liner assembly was made. In the alternative, the release liner assembly can be rolled and shipped to a remote location without the second adhesive layer having been applied. In such a case, the release liner need not contain an adhesive release agent on its exposed surface and the second adhesive layer can be applied in a heated liquid state at the remote location to either the exposed surface of the fiberglass blanket or to the second broad surface of the carrier immediately prior to joining the blanket with the carrier of the release liner assembly. 
     Although the present invention has been described with respect to specific details of certain preferred and other important embodiments thereof, it is not intended that such details limit the scope and coverage of this patent other than as specifically set forth in the following claims.