Patent Publication Number: US-2007110949-A1

Title: Flocked adhesive article

Description:
CROSS REFERENCE TO RELATED APPLICATION  
      The present application claims the benefits, under 35 U.S.C. §119(e), of U.S. Provisional Application Ser. No. 60/738,152, filed Nov. 17, 2005, entitled “Flocked Adhesive Article”, which is incorporated herein by this reference. 
    
    
     FIELD OF THE INVENTION  
      The invention relates generally to flocked articles and particularly to flocked adhesive articles.  
     BACKGROUND OF THE INVENTION  
      Flocked articles are used in a wide variety of applications. For example, flocked articles are used as patches, transfers, molded objects, and the like. Flock is much less expensive than woven articles while providing a more plush feel. To maintain the plush feel, it is important to not only to provide for the proper orientation of the flock relative to the adhesive layer but also prevent the permanent adhesive from flowing into and between the flock fibers.  
      One technique for accomplishing these objectives is to adhere a pre-formed, self-supporting thermosetting adhesive film to the flock. The use of the self-supporting film inhibits flow of the adhesive too far up the fibers. The adhesive, when fully activated or cross-linked, can permanently adhere the flock to a desired substrate. A problem, however, exists in the need of a downstream user to apply the high temperatures needed to fully cross-link the adhesive when it is applied to the substrate.  
      There is thus a need to provide a flocked article having a high degree of plushness and an adhesive that can be applied at lower temperatures, such as the temperature of a hot iron.  
     SUMMARY OF THE INVENTION  
      These and other needs are addressed by the various embodiments and configurations of the present invention. The present invention is directed generally to an article having adjacent thermoset and non-thermosetting (e.g., thermoplastic and hot melt adhesives) adhesive layers arranged so that the thermoset adhesive layer is between the flock and non-thermosetting adhesive layer. Before the thermoplastic adhesive layer is melted, the thermoset adhesive layer is fully activated (or cross-linked) to firmly attach to the flock fibers while inhibiting flow of the non-thermosetting adhesive (after application) into and between the flock fibers. In this manner, a high degree of plushness is maintained in the flock layer without compromising the bond strength between the fibers and thermoset adhesive layer.  
      In one embodiment, the non-thermosetting adhesive layer is a thermoplastic adhesive, and the thermoset adhesive layer is contacted with the flock fibers and thermoset fully before the thermoplastic adhesive layer is contacted with the thermoset adhesive layer. It has been discovered that, when the two adhesive layers are applied simultaneously or substantially simultaneously to the flock layer, the curing agents can migrate into the thermoplastic adhesive layer and cause it to set irreversibly or thermoset. By applying the adhesive layers at differing times, this problem can be avoided. The curing agents in the previously thermoset thermoset adhesive layer are immobilized by the cross-linking and thereby prevent from migrating into the thermoplastic adhesive layer.  
      These and other advantages will be apparent from the disclosure of the invention(s) contained herein.  
      As used herein, “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.  
      The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side view of a flocked carrier sheet according to an embodiment of the present invention;  
       FIG. 2  is a side view of a flocked intermediate assembly according to an embodiment of the present invention;  
       FIG. 3  is a side view of a flocked article according to an embodiment of the present invention;  
       FIG. 4  is a side view of a manufacturing line for the flocked article of  FIG. 3 ; and  
       FIG. 5  is a flow chart of the manufacturing line of  FIG. 4 . 
    
    
     DETAILED DESCRIPTION  
      While the non-thermosetting adhesive layer is discussed in the embodiments below solely in the context of a thermoplastic adhesive, it is to be understood that the non-thermosetting adhesive may be any adhesive that does not thermoset if heated to a high enough temperature. Rather, non-thermosetting adhesives will only melt if heated to a high enough temperature. For example, thermoplastic adhesives are generally thermally reversible while thermosetting or thermoset adhesives are generally thermally irreversible. By heating thermoplastic adhesives to a high enough temperature, the adhesive may be bonded reversibly to a substrate. Examples of adhesives other than thermoplastic adhesives include hot melt adhesives, binder adhesives, tack adhesives, and the like.  
       FIG. 3  shows a flocked article  300  according to an embodiment of the present invention. The article  300  includes a carrier sheet  304 , release adhesive layer  308 , flock layer  312 , thermosetting adhesive layer  316 , thermoplastic adhesive layer  320 , and optional backing material  324 . As can be seen from  FIG. 3 , the flock fibers in the flock layer  312  are substantially perpendicular to the planes of the carrier sheet  304  and adhesive layers  316  and  320  to provide a plush feel. To adhere the article  300  to a desired substrate, the backing material  324  is removed, the adhesive layer  320  placed against the substrate (not shown) surface, and heat and pressure applied to the carrier sheet  304 . The heat will melt, at least partially, the thermoplastic adhesive layer  320  (without melting the thermosetting adhesive layer  316 ). When the heat is removed, the thermoplastic adhesive layer  320  will adhere reversibly (but permanently absent remelting) to the substrate.  
      The carrier sheet  304  can be any desirable sacrificial carrier, such as cellulose (paper), microporous substrate (such as described in U.S. Pat. No. 6,025,068 and copending U.S. Provisional Application Ser. Nos. 60/628,836, filed Nov. 16, 2005, 60/676,124, filed Apr. 28, 2005, 60/703,925, filed Jul. 28, 2005, 60/704,681, filed Aug. 1, 2005, 60/707,577, filed Aug. 11, 2005, 60/710,368, filed Aug. 22, 2005, 60/716,869, filed Sep. 13, 2005, 60/719,469, filed Sep. 21, 2005, and 60/719,098, filed Sep. 20, 2005, to Abrams, each of which is incorporated herein by this reference), and other known carriers. The release adhesive  308  can be any suitable adhesive, such as those disclosed in any of the above copending U.S. provisional applications.  
      The flock  312  used in any of the processes discussed herein can be any electrostatically chargeable fiber, such as fibers made from rayon, nylon, cotton, acrylic, and polyester. Preferably, the flock preferably has a melting and/or softening point that is greater than and is resilient under the temperatures and pressures experienced in design manufacturing and later application processes to resist softening, deformation, and melting. Due to its low melt point, acrylic flock is undesirable in many applications. Resilient flock, such as rayon, nylon, and terephthalate (e.g., poly(cyclohexylenedimethylene terephthalate) polymer flock, is particularly preferred. In most applications, the flock orientation is at least substantially orthogonal (perpendicular) to the first side of the elastic film.  
      The thermosetting adhesive  316  can be any high polymer that solidifies or sets irreversibly when heated above a specific temperature (typically its softening temperature). In other words, the adhesive is commonly non-tacky and thermoplastic in nature as prepared and, upon heating to a suitable temperature, fuses and becomes thermoset or substantially infusible and insoluble. The thermoset state is usually associated with a cross-linking reaction of the molecular constituents induced by heat or radiation. Curing agents, such as organic peroxides and sulfur (in the case of rubber), may be incorporated in the adhesive  316  to facilitate or catalyze the cross-linking reaction. For example, linear polyethylene can be cross-linked to a thermosetting material either by radiation or by chemical reaction. Examples of thermosetting adhesives include rubber, polyolefins, polyesters (e.g., poly(ethylene terephthalate)), polystyrenes, polyethylenes, acrylics, polyurethanes, poly(vinyl chlorides), nylons, phenolics, alkyds, polypropylene, amino resins, polyesters, fluorocarbons, epoxides, rubbers, silicones, and cellulosic and acrylic resins.  
      In one formulation, the adhesive, when in the thermoplastic state, includes a compound containing three or more isocyanate groups per molecule (such as triphenylmethane, triisocyanate, benzene triisocyanate, tolylene triisocyanate, silicon triisocyanate, ethylene tetraisocyanate, and diphenyl triisocyanate) in which a number of the isocyanate groups are blocked or masked with an isocyanate splitter-type material (such as a phenols and malonic ester), and a polyester containing three or four hydroxyl groups (such as glycerin, trimethylol propane, pentaerythritol, various polyesters with excess hydroxyl groups, and phenol formaldehyde resins). To convert the adhesive to the thermoset state, the adhesive is heated to a higher temperature, for example about 125 degrees Celsius or higher, for a short period of time to free the isocyanate groups from the masking or blocking material and permit their reaction with the hydroxyl groups of the polyester. To accelerate the decomposition reaction or the splitting off of the splitter-type material, a small amount of an accelerator such as a tertiary amine compound, tributyl amine, and tris-(dimethyl aminomethyl) phenol, may be added.  
      The thermoplastic adhesive  320  can be any high polymer that softens when heated and returns to its original condition when cooled to room temperature. In other words, the post-heated state of the adhesive is reversible while that of a thermoset adhesive is irreversible. The adhesive  320  can be rubber, polyolefins, polyesters (e.g., poly(ethylene terephthalate)), polystyrenes, polyethylenes, acrylics, polyurethanes, poly(vinyl chlorides), nylons, phenolics, alkyds, polypropylene, amino resins, polyesters, fluorocarbons, epoxides, rubbers, silicones, and cellulosic and acrylic resins.  
      The backing material  324  can be any sacrificial material, including those identified above for the carrier sheet  304 . The material  324  is discarded after removal.  
      The system and process for manufacturing the article  300  will now be discussed with reference to  FIGS. 4-5 .  
      In step  500 , a flocked carrier sheet  100  (depicted in  FIG. 1 ) is provided. The flocked carrier sheet  100  is preferably formed by screen printing the release adhesive film  308  in a desired pattern (which is typically the reverse of the desired final flock pattern) on the carrier sheet  304  followed by flocking electrostatically the carrier sheet  304 . In the system of  FIG. 4 , the flocked carrier sheet  100  is dispensed on a first roll  400 .  
      In step  504 , the flocked carrier sheet  100  is contacted with a pre-formed, self-supporting thermoset adhesive film  200  (which is a combination of the thermoset adhesive layer  316  in the thermoplastic state and a sacrificial backing material  328  as shown in  FIG. 2 ). In the system of  FIG. 4 , the film  200  is dispensed on a second roll  404 .  
      While in contact, the flocked carrier sheet  100  and film  200  enter into a first lamination station  408 . In the station  408 , the film  200  is preferably heated to a temperature of at least about 300 degrees F. and more preferably from about 310 to about 450 degrees F. (or preferably above the softening point of the adhesive layer  316 ) while pressure (which depends on the density of the flock fibers), preferably of at least about 1 psi and more preferably ranging from about 5 to about 25 psi, is applied to the backing material  328  to cause the flock fibers to penetrate the surface of the adhesive layer  316 . As will be appreciated, the orientation can be reversed such that the carrier sheet  304  is on top and the backing material  328  on bottom in which case pressure is applied to the carrier sheet  304 . In this step  508 , the adhesive layer  316  is heated for a sufficient time (typically from about 15 seconds to about 5 minutes) for the layer  316  to enter into the thermoset state, or cross-link substantially completely. The thermoset adhesive layer  316  will, as noted below, form a blocking layer to inhibit the thermoplastic adhesive layer  320  from flowing into and between the flock fibers and thereby compromising the degree of plushness of the flock fibers.  
      The flocked intermediate assembly  204  (shown in  FIG. 2 ) is allowed to cool to a temperature below the maximum temperature experienced in the first laminating station  408 .  
      In step  512 , the backing material  328  is removed from the fully activated thermoset adhesive layer  316 . This can be done by any suitable technique known to those of ordinary skill in the art.  
      In step  516 , the fully activated thermoset adhesive layer  316  (now in the thermoset state) is contacted with the thermoplastic adhesive film  330  (which is a combination of the thermoplastic adhesive layer  320  and backing material  324 ). In the system of  FIG. 4 , the film  330  is dispensed on a third roll  412 .  
      While in contact, the assembly  204  and film  330  enter into a second lamination station  416 . In the station  416 , the film  330  is preferably heated to a temperature of at least about 300 degrees F. and more preferably from about 310 to about 375 degrees F. (or preferably above the softening point of the adhesive layer  320 ) while pressure (which depends on the density of the flock fibers), preferably of at least about 1 psi and more preferably ranging from about 5 to about 25 psi, is applied to the backing material  324  to cause the adhesive layer  316  to firmly contact and adhere to the adhesive layer  320 . As will be appreciated, the orientation can be reversed such that the carrier sheet  304  is on top and the backing material  324  on bottom in which case pressure is applied to the carrier sheet  304 . In this step  520 , the adhesive layer  320  is heated for a time typically ranging from about 1 to about 15 seconds. The thermoset adhesive layer  316  forms a blocking layer to inhibit the thermoplastic adhesive layer  320  from flowing into and between the flock fibers.  
      The adhesive layers  316  and  320  have differing properties. As will be appreciated, the adhesive layer  316 , when heated, is more viscous (and therefore more resistant to flow) than the adhesive layer  320 , when softened. While not wishing to be bound by any theory, this is believed to be from the cross-linking reaction occurring rapidly in the adhesive layer  316 . This higher viscosity limits the ability of the softened adhesive layer  316  to flow up and between the flock fibers, thereby maintaining plushness of the flock layer  312 . Typically, the softening point of the thermoset adhesive layer  316  in step  508  is greater than the softening point of the thermoplastic adhesive layer  320  in step  520 .  
      The decorative article of  FIG. 3  is outputted by the second laminating station  416 .  
      A number of variations and modifications of the invention can be used. It would be possible to provide for some features of the invention without providing others.  
      For example in one alternative embodiment, decorative media other than flock can be used in the article in place of the flock layer  312 . For example, glitter, glass beads, metal foil, and other decorative materials may be employed.  
      In another alternative embodiment, the thermoset and/or thermoplastic adhesive layers are applied in liquid form rather than solid form.  
      In yet another alternative embodiment, the flock is applied directly to the thermoset layer  316  with or without an intermediate adhesive on the surface of the layer  316  to hold the flock in position until the flock is pressed into the softened thermoset layer  316  in a lamination station. In one configuration, the thermoset adhesive layer is heated to the point of being tacky (while still in the thermoplastic state) and the flock fibers electrostatically flocked into the tacky adhesive layer. The adhesive layer may then be heated to a higher temperature to soften further and cross-link the adhesive to the thermoset state while the flock fibers are pushed into the softened adhesive. In this embodiment, steps  504 ,  508 ,  512 ,  516 , and  520  remain the same, and the intermediate assembly does not have the carrier sheet  304  and release adhesive  308  positioned on top of the flock layer  312 .  
      The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.  
      The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.  
      Moreover, though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.