WO2001026893A1

WO2001026893A1 - Repositionable article

Info

Publication number: WO2001026893A1
Application number: PCT/US2000/041307
Authority: WO
Inventors: Thomas H. Owen; John M. Questel
Original assignee: Owen Thomas H; Questel John M
Priority date: 1999-10-15
Filing date: 2000-10-16
Publication date: 2001-04-19
Also published as: AU2116401A

Abstract

This invention provides articles and in particular shelf and drawer liners which do not require a release layer and are capable of being repositioned on a surface while adhering to the surface prior to being bound to the surface.

Description

REPOSITIONABLE ARTICLE

Field of the Invention

This invention relates to articles which can be placed on a surface, repositioned prior to adhesion, and then adhered without the application of additional adhesive.

Background of the Invention

Conventional adhesive sheets, such as adhesive wallcovering, are made from a base material, such as paper, coated with an adhesive. Wallpapers typically include water activatable adhesives which require wetting for them to bond to a substrate. Once water is added to the adhesive, the wallpaper sticks easily and permanently to substrates. As a result, positioning such sheets on surfaces is often quite difficult because the sheets cannot be moved once they initially touch the surface.

U.S. Patent No. 3,331,729 describes an adhesive bonding product having microspheres sparsely, but uniformly, distributed over a pressure sensitive adhesive layer. The object containing the adhesive can be positioned on the surface to which it is to be adhered prior to pressing against the object to make a firm bond. Similarly, U.S. Patent No. 4,556,595 describes a pressure sensitive adhesive sheet having non-adhesive solid microparticles distributed over the surface of the adhesive layer.

Adhesive sheets made according to these patents, however, have no adhesive characteristics when initially applied to a surface. They only adhere to the surface upon application of substantial pressure, which strongly binds the sheet to the surface. The sheet cannot thereafter be repositioned. For this reason, it is difficult for one person to align such sheets.

U.S. Patent No. 5,639,539 discloses a releasable wall covering and method of manufacture. The wall covering has a reinforcing substrate or backing layer with a surfacing layer formed of a polymer coating overlying a front surface of the backing layer. A layer of printing is applied to the surfacing layer, and a transparent top coat layer extends substantially over the entire printed area. A PSA layer underlies a rear surface of the backing layer to secure the wall covering to the wall, while allowing it to be repositionable upon installation and releasable after extended use . The pressure sensitive layer contains tacky polymeric microspheres to facilitate easy release of the wall covering from the wall surface.

Many wallpapers and shelf liners have designs printed on their surfaces.

The inks from these designs often stick to objects which contact such wallpapers and shelf liners resulting in a damaged appearance for all of these items.

Therefore, it is an object of the present invention is to provide an article containing a surface which is slippable and permits easy movement during alignment of the article, but thereafter allows the article to be adhered to the surface by application of sufficient pressure. It is also an object of the invention to provide an article that can be initially positioned by application of a small amount of pressure without strongly adhering the article to the surface. The article can than be repositioned, if necessary, and subsequently can be strongly adhered.

It is yet another object to provide an object which does not transfer ink to objects laying on it.

Since release layers often significantly increase the cost of drawer and shelf liners, it is a further object of the invention to provide an article which does not require a release layer and unwinds easily from a roll.

Another object of the invention is to provide an article which can be removed, after adhesion to a substrate, with minimal effort while leaving little or no residue on the substrate. Summary of the Invention

The present invention relates to an article, preferably a shelf or drawer liner, capable of being repositioned on a substrate prior to being adhered to the substrate. The article can either be of the type which is removable from the substrate only by wetting, scraping or steaming or which is removable from the substrate by other methods. The article includes:

(a) a polymeric layer having a substrate-facing surface and a non-adhering surface;

(b) ink coated on at least a portion of the non-adhering surface;

(c) a total coverage ink layer covering at least a portion of the ink and the substrate-facing surface; and

(d) a low tack adhesive layer covering at least a portion of the total coverage ink layer, the low tack adhesive layer comprising an adhesive and microparticles dispersed therein. Since the ink in the article of the present invention is sandwiched between the polymeric layer and the total coverage ink layer, the ink dos not stick to the substrate to which the article is adhered or to objects placed on the polymeric layer of the article. Additionally, the total coverage ink layer provides good anchorage for the low tack adhesive layer and thereby prevents residue from remaining on a substrate to which the article was adhered upon removal.

The invention also relates to methods of forming the article, and methods of applying the article to a substrate.

Brief Description of the Drawings Fig. 1 is a plan view of one embodiment of a slippable adhesive sheet of this invention.

Fig. 2 is an enlarged cross-section view of Fig. 1 along the X line. Fig. 3 is a cross-section of one embodiment of an adhesive sheet of the invention having a release layer and a peelable layer on the non-adhering surface of the substrate. Detailed Description of the Invention

The present invention relates to articles, such as shelf liners, which have good durability, do not require release paper, and include adhesive systems which permit positioning of the article on a surface to allow easy registering of the article with a desired site of bonding. Once the article has been positioned, it can then be adhered to the substrate by applying sufficient pressure to fracture microparticles in the low tack adhesive layer. Furthermore, the article easily unwinds from a roll, even when the article does not have a release layer.

The low tack adhesive layer preferably also exhibits low peel adhesion. Application of a small amount of pressure to the article does not cause the article to adhere substantially, and the article can thereafter be easily repositioned.

The article can be, for example, a shelf liner, drawer liner, sheet, wallcovering, wall trim, panel, tile, picture, poster, sticker, wall hanging, decorative applique, appliance panel, cabinet finish, insulation panel, billboard, display, or any other article that can be adhered to a surface. Preferably, the article is lightweight.

Most preferred articles include, but are not limited to, shelf liners and drawer liners.

Figures 1 and 2 depict a preferred embodiment of the invention: a slippable sheet which includes a polymeric layer (12) having a substrate-facing surface

(13) which will face a substrate to which the article is adhered and a non-adhering surface (11). Preferably, the non-adhering surface does not have a coating or ink on it. Such slippable sheets can be used as, for example, shelf liners and drawer liners.

The polymeric layer may be made of, for example, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl chloride, or any combination of any of the foregoing.

The polymeric layer preferably has a thickness of from about 0.003 to about 0.012 inches , more preferably from about 0.004 to about 0.008 inches , and most preferably from about 0.004 to about 0.006 inches.

One or more inks are coated on the substrate-facing surface (13) of the polymeric layer (12), typically, to provide a decorative pattern. The inks may be polyamide based inks or other resin based inks. The inks are preferably ones which adhere well to the polymeric layer. Preferably, the inks are polyamide based inks, such as UNI-REZ^® 2636 available from Union Camp Corp. of Wayne, N.J.

A total coverage ink layer (14) having a substrate-facing surface (17) and a polymeric layer-facing surface (19) is disposed between the polymeric layer (12) coated with ink (15) and a low tack adhesive layer (16). This layer provides background and contrast to the ink coated on the polymeric layer. This layer also provides good anchorage for the low tack adhesive layer so that the shelf liner may be removed from the substrate to which it is adhered without leaving any residue. The total coverage ink is preferably modified so that the total coverage ink layer adheres well to the first adhesive layer. The total coverage ink is typically comprised of a polyamide based ink, such as UNI-REZ^® 2636 available from Union Camp Corp. of Wayne, N.J.; colored pigments; and an appropriate alcohol solvent.

The total coverage ink layer preferably has a thickness of from about 0.0001 to about 0.0005 inches, more preferably from about 0.0002 to about 0.0004 inches, and most preferably from about 0.00025 to about 0.0003 inches.

A surface, preferably the substrate-facing surface (17) of the total coverage ink layer (14), is at least partially covered with the low tack adhesive layer (16) having a substrate-facing surface (21) and a polymeric layer-facing surface (23). The low tack adhesive layer (16) preferably is continuous and covers the entire substrate-facing surface of the total coverage ink layer. The low tack adhesive layer contains adhesive that preferably exhibits high adhesion.

The adhesive may be removable, for example, by peeling without any treatment. In a preferred embodiment, the adhesive in the low tack adhesive layer is a solvent-borne or waterborne low tack adhesive. This allows the low tack adhesive layer to be applied evenly to the surface of a sheet-like polymeric layer.

The low tack, adhesive layer (16) contains microparticles (25) dispersed throughout and preferably uniformly dispersed . It may be continuous or discontinuous .

The low tack adhesive layer can contain a high tack adhesive. The particular combination of adhesive and microparticles determines the tack of the layer. Thus, a high tack adhesive, e.g., exhibiting a tack of more than 600 grams as described in ASTM D-2979, can be combined with microparticles to obtain a layer that has low tack because the microparticles contact the surface to be adhered to (resulting in contact over a small surface area) . Preferably the low tack adhesive layer exhibits a tack of less than about 200 g/cm², more preferably less than about 50 g/cm², and most preferably less than about 5 g/cm². The adhesive is preferably capable of strongly adhering the sheet to the substrate surface to which it is to be adhered.

The adhesive in the low tack adhesive layer also preferably exhibits low peel adhesion. This allows the sheet to be easily repositioned after an amount of pressure is applied which is low enough that the sheet is not substantially adhered by the adhesive contained in the base adhesive layer. Preferably, the adhesive, as diluted in the low tack adhesive layer, exhibits a peel adhesion of less than about 0.75 pounds per lineal inch as described in ASTM D-903 and more preferably less than about 0.2 pounds per lineal inch.

The low tack adhesive layer preferably has a Brookfield LV viscosity of between about 800 and about 1500 cps at 25°C. Microparticles are dispersed substantially uniformly throughout the low tack adhesive layer. Suitable microparticles may be hollow, solid, or a combination thereof. The microparticles can be breakable or non-breakable upon application of pressure to the article. The microparticles can also be collapsible (without breaking) upon application of pressure to the article, or non-collapsible. Preferred are microparticles that are breakable, and non-collapsible.

The microparticles can be made of any material having the appropriate size and other desired characteristics. For example, the microparticles can be made of glass, silica, clay, urea-formaldehyde resin, acrylate polymer, acrylate copolymer, rubber, foamed organic polymers, polytetrafluoroethylene, phenolic resin, calcium carbonate, aluminum hydroxide, ferrous oxide, or styrene resin. Hollow glass microspherules are preferred.

The microparticles can be of any diameter less than about 500 microns (i.e. , 0.02 inch). Preferably, a mixture of microparticles have diameters less than about 200 microns (i.e., 0.008 inch) is used. In one embodiment, the microparticles are microspheres having mixed diameters less than about 125 microns (i.e., 0.005 inch).

Suitable microparticles are commercially available, and include Scotchlite™ "glass bubbles" (3M Co. , St. Paul, Minn.), Dualite™ hollow spheres (Pierce & Stevens Corp . , Buffalo , NY) , Q-CEL™ " extendospheres " (PQ Corp . , Valley Forge, PA), Extendospheres "BUBBLECUP" (PA Industries, Inc. , Chattanooga, TN), and Expancel™ microspheres (Expancel Inc. , Diluth, GA). Scotchlite™ K37 "glass bubbles" (3M Corp. , St. Paul, MN) are particularly preferred. These microspheres have mixed diameters of less than 125 microns and a typical density of about 0.37 g/cm².

The low tack adhesive layer preferably has a rough, or contoured, surface caused by protuberance of the microparticles. This lowers the surface area of the adhering surface that contacts the surface to be adhered to and can cause the low tack layer to exhibit its low tack. Thus, the thickness of the low tack adhesive layer at any point can vary depending on the diameter of any microparticle present at that point. The thickness of the low tack adhesive layer, measured at the thickest point, is preferably less than about 0.01 inch, more preferably less than about 0.005 inch. The thickness of the low tack layer measured at the thinnest point is preferably less than the diameter of the largest microparticles. In a preferred embodiment, the low tack adhesive layer is applied as an aqueous dispersion on top of the total ink coverage layer and dried, e.g., in an oven.

Conventional pressure sensitive adhesives can be used in the low tack adhesive layer. These can be chosen from among, for example, acrylic adhesives and rubber resin adhesives. Acrylic adhesives include, for example, homopolymers, copolymers or crosslinked copolymers of at least one acrylic or (meth)acrylic component, for example acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, hexyl acrylate, octal acrylate, 2-ethylhexyl acrylate, undecyl acrylate or lauryl acrylate, or as a comonomer, a carboxyl-containing monomer such as (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride or butyl maleate, a hydroxyl-containing monomer such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate or allyl alcohol, an amido-containing monomer such as (meth)acrylamide, N-methyl(meth)acrylamide or N-ethyl(meth)acrylamide, a methylol group-containing monomer such as N-methylol(meth)acrylamide or dimethylol(meth)acrylamide, an amino-containing monomer such as aminoethyl(meth)acrylate, dimethylaminoethyl(meth)acrylate or vinylpyridine, or a non-functional monomer such as ethylene, propylene, styrene or vinyl acetate.

Rubber adhesives include, for example, natural rubber, isoprene rubber, styrene-butadiene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, butyl rubber, polyisobutylene, silicone rubber, poly vinyl isobutyl ether, chloroprene rubber and nitrile rubber.

Pressure sensitive adhesives are preferred. Suitable pressure sensitive adhesives for use in the invention are commercially available. A preferred commercially available pressure sensitive adhesive for use in the low tack adhesive layer is Flexcryl™ 1625 (Air Products Allentown, PA), an acrylic polymer based adhesive.

Preferred adhesives for the low tack adhesive layer include, but are not limited to, water emulsion acrylic copolymer pressure sensitive adhesives, water emulsions of tackified resin-rubber pressure sensitive adhesives, and solvent-borne adhesives thereof.

The low tack adhesive layer can independently contain surfactants, rheology modifying agents, antioxidants, tackifiers, adhesives, plasticizers, fillers, or any combination thereof. Suitable surfactants include, but are not limited to, alkyl hydroxy alkynes, such as Surfynol™ available from Air Products of Allentown, PA. Suitable rheology modifiers include, but are not limited to, water soluble polymers, such as Roplex™ 6038 available from Rohm & Haas of Philadelphia, PA.

Tackifying agents may be added if desired. Such agents are well known in the art. Typical commercially available agents include resins with ring and ball softening point from 85-115°C. Preferred tackifying agents include, but are not limited to, ester tackifying resins, such as ZONESTER™ resins (Arizona Chemical, Panama City, FL), and, in particular, abietic acid glyercol esters, such as ZONESTER™ 85; polyterpene tackifying resins, such as PICCOLYTE™ (Hercules, Wilmington, DE); hydrocarbon resins from the C₅-C₉ oil refining stream, such as ESCOREZ™ (Exxon, Houston, TX) and WINGTACK™ (Goodyear, Akron, OH); or any combination of any of the foregoing. When the low tack adhesive is a waterborne low tack pressure sensitive adhesive, the tackifying agent may be emulsified prior to addition to the adhesive. If desired , the non-adhering surface ( 11 ) of the polymeric layer ( 12) can be covered with a release layer comprising, for example, a coating containing silicone, a paraffinic material, an over-print varnish, or a combination of any of the foregoing, or with a peelable release layer, such as silicone coated papers. Such layers are well known in this art. Suitable silicone coated release papers include, but are not limited to, those available from Enterprise Tape Company of Dolton, IL, and Thilmany Pulp & Paper Co. of Kaukauna, WI. UV 9300 (GE Silicones, Waterford, NY) is one commercially available release layer. Another is a three component system which includes a water based dimethyl siloxane emulsion (such as, for example PC 188), a curing catalyst of a water based platinum solution (such as, for example, PC60) and a thickener in the silicone matrix (such as, for example, Carboxymethyl Cellulose (CMC)). Thickeners and other rheology modifying agents are often included in the release layer in order to prevent the silicone from penetrating into the other layers of the article. The thickener level is typically about 0.1 to about 3.0% by weight, and a preferred silicone system is mixed as follows: 20 parts silicone emulsion PC 188 + 1 part platinum catalyst solution + 0.1 % - 3.0% Carboxymethyl Cellulose. Figure 3 shows such a sheet having a polymeric layer (12) with a non- adhering surface (11), which may be covered with a release layer (22) and/or a peelable layer (24). Such layers are conventionally applied, and act to reduce and stabilize unwind tension. Suitable substrates include, but are not limited to, shelves, drawers, walls, and the like. When the slippable sheet of the invention is applied to a surface, the surface is in contact with the low tack adhesive layer. The overall low tack of this layer allows the slippable sheet to be easily moved or repositioned. For example, wall covering having a printed surface can be easily moved to obtain registration of the print pattern. Pressure may then be applied by hand to a portion of the adhesive sheet, usually the top of the sheet, in order to break the microparticles dispersed in the low tack adhesive layer. If a low degree of pressure is applied, such as normally occurs when pressing with the hand, the pressure sensitive adhesive in the low tack adhesive layer can primarily hold the sheet in place while the rest of the sheet is positioned. Once the rest of the sheet is positioned, higher pressure can be applied, such as with a squeegee, to allow the low tack adhesive to strongly adhere the sheet to the surface. Use of a removable adhesive, as opposed to a permanent adhesive, allows the sheet to be removed without wetting, scraping, or steaming at a later date, if desired. The article of this invention can be made by conventional means . In one manufacturing process, one surface of a roll of polymeric material is coated with ink, preferably in a decorative pattern, by conventional machines, such as, for example, a flexo or gravure press. A total coverage ink layer is then applied onto the surface of the polymeric material which is coated with ink. The polymeric material is fed through various idler and tensioning rollers, as is well known by those skilled in the art, where the first adhesive is applied over the total coverage ink layer. An adhesive application roller or slot die may be used to apply a controlled and evenly distributed amount of the low tack adhesive. A reverse roll is preferred as the coating head in the application process. A wire wound coating head has also been found to be suitable. The low tack adhesive layer is dried prior to use.

All patents, applications, publications, and test methods mentioned herein are hereby incorporated by reference. Many variations of the present invention will suggest themselves to those skilled in this art in light of the detailed description herein. All such obvious variations are within the full intended scope of the claims appended hereto.

Claims

IN THE CLAIMS:

1. An article comprising:

(a) a polymeric layer having a substrate- facing surface and a non-adhering surface;

(b) ink coated on at least a portion of said substrate-facing surface;

(c) a total coverage ink layer covering at least a portion of said ink and said substrate- facing surface; and

(d) a low tack adhesive layer covering at least a portion of said total coverage ink layer, said low tack adhesive layer comprising an adhesive and microparticles dispersed therein.

2. An article as defined in claim 1, wherein said polymeric layer comprises polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl chloride, or any combination of any of the foregoing.

3. An article as defined in claim 1 , wherein said polymeric layer has a thickness ranging from about 0.004 to about 0.006 inches.

4. An article as defined in claim 1 , wherein said microparticles cause said low tack adhesive layer to have a surface for adhering that is not flat.

5. An article as defined in claim 1, wherein said low tack adhesive layer is removable by peeling.

6. An article as defined in claim 1 , wherein said adhesive is selected from the group consisting of water emulsion acrylic copolymer pressure sensitive adhesives, water emulsions of tackified resin-rubber pressure sensitive adhesives, and solvent-borne adhesives thereof.

7. An article as defined in claim 1 wherein said article is a shelf liner.

8. An article as defined in claim 1 wherein said article is a drawer liner.

9. An article as defined in claim 1, wherein said microparticles are uniformly dispersed in said low tack adhesive layer.

10. An article as defined in claim 1, wherein said microparticles are selected from the group consisting of hollow microparticles and solid microparticles.

11. An article as defined in claim 1 , wherein said microparticles are comprised of a material selected from the group consisting of glass, silica, clay, urea- formaldehyde resin, acrylate polymer, acrylate copolymer, rubber, foamed organic polymers, polytetrafluoroethylene, phenolic resin, calcium carbonate, aluminum hydroxide, ferrous oxide, and styrene resin.

12. An article as defined in claim 1, wherein said microparticles are hollow glass spheres.

13. An article as defined in claim 12, wherein said glass spheres have diameters less than about 200 microns.

14. An article as defined in claim 1, wherein said first adhesive comprises a hot melt adhesive.

15. An article as defined in claim 1, wherein said low tack adhesive layer further comprises a surfactant, rheology modifier, antioxidant, tackifier, adhesive, plasticizer, filler, or any combination thereof.

16. An article as defined in claim 1, wherein said low tack adhesive layer has a thickness of less than about 0.01 inches.

17. A method for applying an article to a surface to be adhered to, said method comprising:

(a) positioning an article as defined in claim 1 , on said surface to be adhered to; and

(b) applying sufficient pressure to bring said low tack adhesive layer in contact with said surface and to adhere said article to said surface, wherein the peel adhesion of said article is less than about 0.75 pounds per lineal inch.

18. A method for manufacturing the article of claim 1, said method comprising:

(a) providing a polymeric layer having a substrate-facing surface and a non-adhering surface;

(b) applying ink over at least a portion of said substrate-facing surface;

(c) applying a total coverage ink layer over said ink and the substrate-facing surface of said polymeric layer; and

(d) applying a low tack adhesive layer over said total coverage ink layer, said low tack adhesive layer comprising an adhesive and microparticles dispersed therein.