Composite Pressure Sensitive Adhesive Construction

The present invention relates to specific embodiments of a composite pressure sensitive adhesive construction which is resealable until a permanent seal is desirable. More specifically, the present invention relates to said composite pressure sensitive adhesive constructions which are very readily applied to any container, package, seam, or other item wherein an initial resealable connection is desired, followed by a later permanent-type bond.

Heretofore, various articles or methods have been utilized to join items together. One of the most common articles or methods has been the use of staples, paste, glue, and more recently, pressure sensitive tapes. However, often it is highly desirable to temporarily hold the items together. This renders the use of paste and glue impossible in that any separation after the paste and glue have been applied results in the destruction of a portion of the article. Similarly, the removal of staples will often tear a portion of the article.

Considering pressure sensitive adhesives, various techniques have been utilized and they generally are cumbersome, expensive, and result in a poor quality seal. For example, in the bonding or sealing together of two pieces of material such as the two cover edges of a pipe insulating jacket, paste or glue is highly undesirable in that the edges must first be cleaned, the paste applied, and the edges then held together for a period of time while the paste or glue dries. In addition to this, the installation is often in a very difficult work area, such as a ceiling, which requires an individual operating at the top of a high ladder.

One current method utilizing pressure sensitive adhesives involves a double face coated tape, that is, a tape system having a carrier, adhesive layers applied to both sides of the carrier, and release liners applied to the adhesive layers. One of the release liners would normally be removed so that the tape could be attached to one edge of the jacket or to the item. Upon installation, the remaining release liner would be removed and the adhesive contacted with the other edge. However, this method generally resulted in poor adhesion in that the remaining edge usually acquired dust, dirt, grease, and the like, either during warehousing, shipment, or installation.

Another system utilized heretofire is commonly called the "two-tape" method. According to this system, each tape contained a carrier having an adhesive layer on each side thereof. To each adhesive layer was added a release liner. One of the adhesive faces on each tape was added to each edge of the material either at the factory or on the job. If added on the job, the same problems set forth above were encountered in that the edges would be dirty, greasy, or the like, thus, a good bond of the tape generally was not obtained. Furthermore, an exact registration was difficult to obtain since the on-the-job application often involved working under difficult conditions. If one of the adhesive layers on each of the two tapes was applied to each edge during factory installation, a temporary bond of each edge to each other was not obtained, since, of course, the two remaining release layers would not adhere to each other. Thus, the item such as an insulated coolant or steam pipe jacket would freely open and was subject to abuse, damage, and the like, and further required the need to remove two liners.

It is, therefore, an object of the present invention to provide a composite pressure sensitive adhesive construction for adhering one item to another.

It is another object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein a one-tape system is utilized which requires a minimum amount of work for installation.

It is a further object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein a resealable or a temporary seal is maintained which does not damage or affect any part of the adhered items until a permanent seal is desired.

It is an additional object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein clean, dirt-free edges of different items or the same item joined or adhered together are maintained prior to the formation of the permanent seal, thereby assuring an effective permanent seal.

It is yet another object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein a temporary seal is converted to a permanent seal by the removal of only a single release liner.

It is yet a further object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein said single release liner is a differential release liner.

It is yet another object of the present invention to provide a composite pressure sensitive adhesive construction, as above, wherein said construction may be made up in the form of a roll or in the form of precut tapes.

These and other objects of the present invention will become apparent from the following specification which describes in detail the embodiments without attempting to discuss all of the modifications in which the invention might be embodied.

Generally, a composite pressure sensitive adhesive construction, comprises, a first exterior release liner, a central release liner, and a second exterior release liner, a first pressure sensitive adhesive layer, said first pressure sensitive adhesive layer releasably secured to said first exterior release liner and to one side of said central release liner, a second pressure sensitive adhesive liner, said second pressure sensitive adhesive layer releasably secured to said second exterior release liner and to the remaining side of said central release liner.

Additionally, a composite pressure sensitive adhesive construction, comprises, a first exterior release liner, a first carrier and a central release liner, a first pressure sensitive adhesive layer, said pressure sensitive adhesive layer releasably secured to said first exterior release liner and to one side of said carrier, a second pressure sensitive adhesive layer, said second pressure sensitive layer releasably attached to the remaining side of said first carrier and to one side of said central release liner, a second carrier and a second exterior release liner, a third pressure sensitive adhesive layer, said third pressure sensitive adhesive layer releasably secured to the remaining side of said central release liner and to one side of said second carrier, a fourth pressure sensitive adhesive layer, said fourth pressure sensitive adhesive layer releasably secured to the remaining side of said carrier and to said second exterior release liner.

Generally, a method of adhering one item to another item through a composite pressure sensitive adhesive construction, comprises the steps of, applying a first pressure sensitive adhesive layer to one of said items, said first pressure sensitive adhesive layer attached to a central release liner, applying a second pressure sensitive adhesive layer to a second item, said second pressure sensitive adhesive layer attached to the remaining side of said central release liner, and removing said central release liner and contacting said first adhesive layer with said second adhesive layer to form a bond.

Additionally, another method of adhering one item to another item, comprises the steps of applying a first pressure sensitive adhesive layer to one item, a carrier, a second pressure sensitive adhesive layer, and a central release liner, said carrier attached to said first adhesive layer, one side of said second adhesive layer attached to said carrier and the remaining side of said adhesive layer releasably attached to said central release liner, applying a fourth pressure sensitive adhesive layer to another item, a second carrier and a third adhesive layer, said carrier attached to the remaining side of said fourth adhesive layer to one side of said third adhesive layer, the remaining side of said third adhesive layer releasably attached to said central release liner, and removing said central release liner and contacting said second adhesive layer with said third adhesive layer to form a bond.

Generally, a composite pressure sensitive adhesive construction comprises, an exterior release liner and a central release liner, a first pressure sensitive adhesive layer, said first pressure sensitive adhesive layer releasably secured to said exterior release liner and to one side of said central release liner, and a second pressure sensitive adhesive layer, said second pressure sensitive adhesive layer releasably secured to the remaining side of said central release liner.

Generally, a method of adhering one item to another item through a composite pressure sensitive adhesive construction comprises the steps of, removing an exterior release liner to expose a first pressure sensitive adhesive layer, applying said first pressure sensitive adhesive layer to one item, said first pressure sensitive adhesive layer releasably attached to a central release liner, applying a second pressure sensitive adhesive layer to another item, said second adhesive layer releasably attached to the remaining side of the central release layer, and removing said central release liner and contacting said first adhesive layer and said second adhesive layer to form a bond.

Generally, a composite pressure sensitive adhesive construction comprises, a release liner, a first carrier and a central release liner, a first pressure sensitive adhesive layer, one side of said first adhesive layer releasably secured to said release liner and the remaining side of said first adhesive layer secured to said first carrier, a second pressure sensitive adhesive layer, one side of said second adhesive layer releasably secured to one side of said central release liner with the remaining side of said pressure sensitive adhesive layer secured to the remaining side of said first carrier, a second carrier, a third pressure sensitive adhesive layer, one side of said third pressure sensitive adhesive layer releasably secured to the remaining side of said third adhesive layer secured to said second carrier, a fourth pressure sensitive adhesive layer, one side of said fourth adhesive layer secured to said carrier.

Generally, a method of adhering one item to another item through a composite pressure sensitive adhesive construction comprises the steps of, removing an exterior release liner releasably secured to a first pressure sensitive adhesive layer, applying said first pressure sensitive adhesive layer to one item, a carrier, a second pressure sensitive adhesive layer and a central release liner, said carrier attached to said first adhesive layer, one side of said second adhesive layer attached to said carrier and the remaining side of said second adhesive layer releasably attached to said central release liner, applying a fourth pressure sensitive adhesive layer to another item, a second carrier and a third adhesive layer, said second carrier attached to the remaining side of said fourth adhesive layer and to one side of said third adhesive layer, the remaining side of said third adhesive layer releasably attached to said central release liner, and removing said central release liner and contacting said second adhesive layer with said third adhesive layer to form a bond.

FIG. 1 is a cross-sectional view of one embodiment of a composite pressure sensitive adhesive construction according to the present invention.

FIG. 2 is a cross-sectional view of another embodiment of a composite pressure sensitive adhesive construction according to the present invention.

FIG. 3 is a plan view of a pipe insulation jacket having the composite pressure adhesive construction of the present invention joining two ends of the insulating jacket cover.

FIG. 4 is a plan view showing the insulation jacket in an open position with a pipe in one section thereof, an exposed pressure sensitive adhesive layer to one longitudinal end portion of the cover and the partial removal of a central release liner thereby exposing another pressure sensitive adhesive layer on the remaining longitudinal end portion of the cover.

FIG. 5 is a plan view showing the insulation jacket in a closed position about a pipe wherein one longitudinal end portion of the cover has been bonded to the other longitudinal portion of the cover through the pressure sensitive adhesive layers.

FIG. 6 is a side view showing a composite pressure sensitive adhesive construction similar to FIG. 1 in the form of a self-wound roll.

FIG. 7 is an enlarged fragmentary view showing a composite pressure sensitive adhesive construction similar to FIG. 2 in the form of a self-wound roll.

According to the concepts of the present invention, a composite pressure sensitive adhesive construction is provided temporarily joining one item to another until a permanent bond is desired. The pressure sensitive adhesive construction has a central release liner with a pressure sensitive adhesive layer releasably attached to each side thereof. An exterior release liner is releasably attached to usually one of the two exposed adhesive layers as when the construction is in the form of a roll, or usually to both of the adhesive layers as when the construction is in the form of a tape. Under clean and quality control conditions, two items may be fastened together through the use of the composite pressure sensitive adhesive constructions. That is, under such conditions, when a construction is utilized in the form of a roll, the first exposed adhesive layer may be applied to any item and then the single exterior release liner may be removed thereby exposing the second adhesive layer which is applied to another item. If the adhesive construction is in the form of a tape, the first exterior release liner is removed and applied to a surface of an item and similarly, the second exterior release liner may be removed with the exposed pressure sensitive adhesive then applied to a second edge or surface of an item. Thus, regardless of the construction utilized, the two edges or surfaces of the same or different items will then be temporarily connected to each other through the pressure sensitive adhesive construction. When a permanent bond is desired, the central release liner is removed, thereby exposing the two remaining sides of the adhesive layers which are then bonded together as through the application of pressure. In other embodiments, a carrier layer with an adhesive layer on one side thereof may be added to the original adhesive layer existing on each side of the central release layer. The application of such a construction to an item or article is similar as in the formation of a permanent bond. Such an embodiment provides bulk or a cushioned construction which is often desirable.

FIG. 1 discloses a preferred embodiment of the invention wherein a composite pressure sensitive adhesive construction is shown, generally indicated by the numeral 10. The composite construction has a central release liner 20 which is coated on each side thereof as at 21 and 22 with a release coating. Generally, any conventional release coating may be utilized such as a silicone coating. Central release liner 20 may vary in thickness from about 1/2 mil to about 5 or 6 mils or higher with thicknesses in excess of this range generally being impracticable due to cost and flexibility. A desirable thickness, in most instances, is from about 1 to 4 mils and preferably 3 to 4 mils when utilized in connection with a pipe jacket. Various common materials and/or films may be utilized for central release liner 20 such as Super Calendered Kraft Paper, polyethylene-coated paper, polyethylene film, polyester films, polyvinyl films, polypropylene films, and the like. The thickness of release coatings 21 and 22 are very small and theoretically need only be a molecule thick so long as the liner is substantially covered. Hence, such release coatings are generally applied by Rotogravure printing, Mayer rod coating, or the like, and are barely measureable, that is, generally being well under 1/10 of a mil. Release coating layers 21 and 22 may be the same material or may be slightly different types of material to affect a tighter release on one side with an easier release on the other side, that is, a differential release. Such a differential release liner is preferred in the present invention so that upon opening of composite construction 10 at central release liner 20, the construction will open at the easier release liner such as, for example, liner 21 and the adjacent adhesive layer 30.

Two pressure sensitive adhesive layers reside upon central release liner 20, that is, one on each side. The first pressure sensitive layer is indicated by the number 30 and is generally the same as the second pressure sensitive layer indicated by the number 35, although they may be different in order to effect a better bond to a specific type of item. Pressure sensitive adhesive layers 30 and 35 generally vary in thickness ranging from about 1/2 mil to about 4 mils with a desirable thickness ranging from about 1 mil to about 2 mils. A preferred thickness is about 11/2 mils. Of course, larger thicknesses can always be used but tend to be uneconomical. Common or conventional pressure sensitive-type adhesives well known to those skilled in the art may be utilized such as an adhesive containing an acrylic base, which may be formulated to any specific purpose, contain flame retardant additives, and the like. Another common class is that of the rubber-based adhesives which may also be formulated with regard to specific purposes and/or uses and, hence, contains dyes, antioxidants, and the like. A specific example of a rubber-based pressure sensitive adhesive is a blend of styrene-butadiene rubber and polyisoprene, and at least a suitable conventional tackifier. Adhesive layers 30 and 35 may be applied to central release liner 20 in any common or conventional manner such as through calendering, coating, or the like.

In order to protect pressure sensitive adhesive layers 30 and 35 during storage, transportation, and the like, or between the time of manufacture and the application to an item or article, two exterior release liners are provided. The first exterior release liner indicated by the numeral 40 is applied to the remaining or exposed surface of first pressure sensitive adhesive layer 30 with a second exterior release liner, indicated by the number 45, being applied to the remaining or exposed side of the second pressure sensitive adhesive layer 35. Exterior release liners 40 and 45 may be constructed of the same material as the central release liner and additionally are of the same thickness as set forth above. Additionally, in order to prevent permanent adhesion or a good bond between the two exterior release liners and the adhesive layers, one side of the exterior liners is coated with a release coating. The release coating may generally be any conventional type of coating, for example, silicone as set forth above with regard to release coatings 21 and 22 and may be very small in thickness, as previously noted. Moreover, release coating 41 which is applied to the first exterior release liner 40 as well as release coating 46 which is applied to the second exterior release liner 45, may be applied in any conventional manner.

The composite pressure sensitive adhesive construction shown in FIG. 1 can be readily made in a manufacturing plant or facility under carefully controlled conditions at ambient temperatures so that good quality is achieved time after time. Moreover, the controlled conditions also insure that no dust, dirt, or contaminates exist between the various adhesive layers and the adjacent layers of material. Additionally, exterior release liners 40 and 45 insure good protection of the adhesive layers. Thus, the quality of the produced item is assured throughout storage, shelf, or warehouse life.

Due to the construction of composite pressure sensitive adhesive laminate 10, it is readily adaptable for application to various items or articles under less than desirable conditions. Generaly, composite construction 10 may be utilized to effect joinder or a bond of any two items. The items may be different parts of the same article such as the edges or ends. Additionally, the joinder may be temporary until a permanent joinder is desired, as upon installation in the field or at the job site. Additionally, the embodiment of FIG. 1 can be wound into a roll for easy dispensing and may be held in the roll in any conventional manner, as upon a reel or the like. Similarly, the embodiment of FIG. 2 can also be wound into a roll for easy dispensing in any conventional manner.

FIGS. 3, 4 and 5 show a typical application of a composite pressure sensitive adhesive construction 10 to an article, generally indicated by the numeral 60. In the specific application shown in FIGS. 3 and 5, adhesive construction 10 has been applied to a specific article in the form of an insulating pipe jacket, generally indicated by the numeral 65. Such an application is generally conducted in a factory where the article 60, such as the pipe jacket 65, is manufactured. In such an environment, first exterior release liner 40 can be removed and first pressure sensitive adhesive layer 30 applied to an item such as the edge or end of the article, for example, the longitudinal end or side 67 of the pipe jacket 65. Similarly, second exterior release liner 45 is removed from composite construction 10 and applied to another item such as the remaining edge or longitudinal end or side 68 of the article. Of course, care is taken during the operation to insure that pressure sensitive adhesive layers 30 and 35 are applied to clean, dirt-free surfaces. In such a situation, a temporary bond is formed between the edges of the article herein, the pipe jacket ends, since central differential release liner 20 still releasably separates the first and second adhesive layers. In order to permit facile separation, central release liner 20 generally may extend outwardly beyond the longitudinal cover end of composite construction 10 such as one-half inch or an inch to permit grasping, as by hand. Additionally, it may also extend axially outwardly beyond the pipe jacket as shown in the left portion of FIG. 3, or beyond the other portion, i.e. the right portion of FIG. 3, or any combination thereof including all three portions.

Referring now to FIGS. 3, 4 and 5, a composite pressure sensitive adhesive construction as set forth in FIG. 1 has been applied to pipe insulating jacket 65 in the manner as set forth immediately above. Thus, in this particular application, cover 66 of insulating pipe jacket 65 has one longitudinal end or side 67 which is attached to the other longitudinal end or side 68 through the pressure sensitive adhesive construction. Cover 66 may be made of any conventional material such as Kraft paper, any plastic material such as polyvinylchloride, polyethylene, nylon, polyurethane, and the like. Additionally, depending upon the use of the particular material, cover 66 may also function as a vapor barrier, a liquid barrier, etc. Whenever insulating pipe jacket 65 is to be applied to a pipe 70, the insulating jacket is opened by grasping differential release liner 20 and applying a force thereto, thereby separating one of the adhesive layers from one side of said release liner. As shown in FIG. 4, insulation portion 69 of pipe jacket 65, which may be made out of any suitable insulating material such as polystyrene foam, polyurethane foam, fiberglass, and the like, is placed about pipe 70. Then, differential release liner 20 is completely removed, thereby exposing first pressure sensitive adhesive layer 30 applied to one end of the pipe jacket. Second pressure sensitive adhesive layer 35 is also exposed by the opening of the pipe jacket. Since, until this application, both pressure sensitive adhesive layers have been constantly covered, the two exposed layers are free of contaminates or other foreign matter. The pipe jacket is then closed with one end of the pipe jacket being pressed against the other end to insure a good permanent and secure bond through adhesive layers 30 and 35.

Thus, a permanent bond is quickly and easily effected, is very simple in operation, requires reduced labor and, hence, reduces cost. Additionally, excellent contact is obtained since adhesive layers 30 and 35 are free from contaminates and furthermore, due to the adhesive-adhesive contact, excellent shear is obtained.

In the embodiment shown in FIG. 2, additional layers have been added to effect a cushioned composite construction which is generally indicated by the numeral 75. This construction is similar to that of FIG. 1 in that it contains a central release liner 80 having release coatings 81 and 82 thereon. Desirably, the release coatings have a different tightness so as to form a differential release liner. A second pressure sensitive adhesive layer 90 resides upon one side of release liner 80 with a third pressure sensitive adhesive coating 95 residing on the remaining side. Moreover, a first exterior release liner 100 having a release coating 101 thereon exists on one end of the construction with a second exterior release liner 105 having a release coating 106 thereon consisting of the other end of the construction. The specific types of material utilized for the various release liners, the release coatings, and the pressure sensitive adhesive layers are the same as set forth above with regard to the embodiment shown in FIG. 1 as are the various broad and desirable thicknesses.

To the second pressure sensitive adhesive layer 90 is added a first carrier layer 110 which may be made out of a matted, a non-woven, or fiber material as well as a film. If a film is utilized, it generally may be the same type of material as used in the release liner. However, a soft or cushioned layer is generally preferred and such layers are preferably made out of fibers or polyester, matted polyester fibers, polyvinylchloride film, polyethylene film, a polyolefin film having from 2 to 8 carbon atoms in the repeating unit, and the like. The thickness of this carrier layer generally ranges from 1/2 mil to about 5 mils with a desirable range being from 2 mils to about 4 mils. Preferred thickness is about 3 mils. A second carrier layer 115 is applied to third adhesive layer 95 and may be made of the same material and may have the same thickness as does the first carrier layer 110.

To the first and second carrier layers 110 and 115 is added another pressure sensitive adhesive layer. Thus, a first pressure sensitive adhesive layer 120 is applied to carrier layer 110 with the first exterior release liner 100 being applied to the first adhesive layer. Similarly, a fourth adhesive layer, 125 is applied to the second carrier layer 115 with the second exterior release liner 105 being applied to the fourth adhesive layer. Adhesive layers 120 and 125 once again can be made from the same adhesive materials as set forth with regard to FIG. 1 and also have the same thicknesses.

The application of a pressure sensitive adhesive construction 75 as set forth in FIG. 2 to an article or item is similar to that set forth in FIG. 1. Thus, the first and second exterior release liners (100 and 105, respectively) are removed with exposed adhesive layers 120 and 125 applied to any portion such as the edges or ends of an item or article. When a permanent bond is desired, a force is applied to differential central release liner 80 to remove the central release liner, then the adhesive laminate or construction is closed and a pressure is applied to the edges or ends of the article to effect a practical permanent bond beween adhesive layers 90 and 95. Preferably, a portion of central release liner 80 extends beyond the other layers of the composite pressure sensitive construction 75 so that such portion may be readily grasped. In addition, this embodiment has the same advantages as the embodiment of FIG. 1 in that it is also produced under quality control conditions free from contaminates and the like. This embodiment through additional adhesive layers 120 and 125 as well as the cushioned carriers 110 and 115, thus produces a cushioned adhesive bond. Such a cushioned construction is often desirable to overcome irregularities in the surface to which it is applied, for example, a textured surface.

Referring now to FIG. 6 of the drawings, a self-wound composite pressure sensitive adhesive construction is shown. The self-wound tape roll is a very desirable product in that it can be readily produced, stored, shipped and then utilized by an end user in applying it to his product. As shown in the expanded side view portion of FIG. 6, the construction of the self-wound tape is identical to FIG. 1 except that one of the release liners such as bottom release liner 45 containing release coating 46 thereon, has been removed so that adhesive layer 35 will be attached to the uppermost surface of the tape layer upon which it resides. In order to prevent permanent or a very good adhesion between the adjacent layers of the tape construction, the top surface of the roll, that is, the top surface of release liner 40, contains a thin coating 50 of any conventional or common release agent such as silicone. Thus, the self-wound roll of tape as shown in FIG. 6 may be readily unwound and applied to any article in a manner similar to that of the construction of FIG. 1 except that, of course, one of the adhesive layers is already exposed and may be applied to an item without having to remove any exterior release liner. The types of various materials utilized for the various release liners, the release coatings, and the pressure sensitive adhesive layers are desirably the same as set forth above with regard to the embodiment shown in FIG. 1. Additionally, the various thicknesses are desirably the same as set forth with regard to the discussion of the embodiment of FIG. 1.

FIG. 7 of the drawings relates to a self-wound composite pressure sensitive adhesive construction wherein only an enlarged portion of the tape is shown. In this embodiment, the construction of the self-wound tape is identical to FIG. 2 except that one of the release liners, such as bottom release liner 105 containing release coating 106 thereon, has been removed so that adhesive layer 125 will be attached to the uppermost surface of the tape upon which it resides. Similarly, in order to prevent a permanent or a good adhesion between the adhesive layers of this tape construction, the top surface of the roll, that is, the top surface of release liner 100, contains a thin coating 130 of any conventional or common release agent such as silicone. As in FIG. 6, the construction of FIG. 7 may be unwound and applied to any article by applying exposed adhesive layer 125 to one item and by removing top exterior release liner 100 and applying the resulting exposed adhesive layer 120 to another item. When a permanent bond is desired, central release liner 80 is removed and adhesive layers 90 and 95 then are contacted with each other. The materials utilized for the various layers are desirably the same as those set forth with regard to the embodiment of FIG. 2 as are the various thicknesses of the individual layers.

The uses of the composite pressure sensitive adhesive constructions are, of course, numerous. Specific examples include carton sealing, gasket applications, molding (e.g. wood, metal, plastic) applications, temporary template followed by a later permanent bond for a vapor or moisture seal, and any of a myraid of applications wherein a temporary bond may be initially desired followed by a permanent bond such as a process of a temporary assembly of pieces, followed by storage, transportation, etc., and then arrangement into a permanent assembly.

While in accordance with the patent statutes, preferred embodiments have been illustrated and described in detail, it is to be understood that the invention is not limited thereto; the scope of the invention being measured solely by the scope of the attached claims.