WO1998000469A1 - Article en mousse microcellulaire avec couche adhesive a topographie modifiee - Google Patents

Article en mousse microcellulaire avec couche adhesive a topographie modifiee Download PDF

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Publication number
WO1998000469A1
WO1998000469A1 PCT/US1997/010979 US9710979W WO9800469A1 WO 1998000469 A1 WO1998000469 A1 WO 1998000469A1 US 9710979 W US9710979 W US 9710979W WO 9800469 A1 WO9800469 A1 WO 9800469A1
Authority
WO
WIPO (PCT)
Prior art keywords
sheet
microcellular foam
cells
foam material
adhesive
Prior art date
Application number
PCT/US1997/010979
Other languages
English (en)
Inventor
Leroy H. Keiser
Original Assignee
Rexam Release Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rexam Release Inc. filed Critical Rexam Release Inc.
Priority to AU35017/97A priority Critical patent/AU3501797A/en
Publication of WO1998000469A1 publication Critical patent/WO1998000469A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/26—Porous or cellular plastics
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers

Definitions

  • This invention relates to sheet materials, and more particularly to sheet materials which include a foamed material as a component, and to processes for making the same .
  • signage for use on the sides of vehicles, in store windows, and the like, can be provided from vinyl sheet materials.
  • the vinyl sheets typically have a design element on a front surface thereof and an adhesive on a rear surface, with a release liner sheet overlying the adhesive. If the release liner is not dimensionally stable upon changes in ambient moisture, heat, and the like, this can adversely affect the appearance of the signage by affecting color and/or shape registrations.
  • Paper substrates typically are not dimensionally stable upon exposure to changes in ambient moisture. For example, the edges of the paper substrate can curl, and/or the substrate as a whole can become wavy. As a result, the substrate can lose lay- flat properties required to maintain the proper alignment or registration of the design elements.
  • Polymer films have much better dimensional stability when exposed to changes in moisture, but can be much more expensive than paper substrates. However, polymer films can be dimensionally unstable and exhibit reduction in tensile properties at elevated temperatures, and therefore some polymer film substrates are unsuited for certain applications where elevated temperatures are encountered during the manufacturing process or in use.
  • face stock, label stock and the like can be difficult to apply to a surface due to the nature of adhesives typically associated with these materials.
  • face or label stock is adhesively secured to a surface by a pressure sensitive adhesive.
  • pressure sensitive adhesives can be difficult to apply to a substrate in a precise location and without entrapment of air due to the pre-adhesion or "quick stick" behavior of such adhesives.
  • composite sheet materials, release liner sheets, face stock, and label stock are provided which include as a component thereof microcellular foam sheet materials.
  • the resulting foam materials can achieve a cell density of several hundred trillions of voids per cubic centimeter and an average void or cell size of less than about 10 microns, preferably less than about 5 microns, and more preferably less than 1 micron, and less.
  • the cell distribution is substantially uniform throughout the foamed material.
  • the topography of a surface of the foam material is modified so as to provide an adhesive surface adjacent thereto which can be slidably positioned (i.e., placed against a substrate surface and easily slid over the surface into proper position without pre-adhering to the substrate) and/or can be repositioned (i.e., applied and adhered to a substrate and thereafter removed and reapplied without substantially distorting, defacing or destroying the adhesive or substrate) .
  • Composite sheet materials, release liner sheets, face stock, label stock, and the like which include microcellular foam sheet materials can exhibit excellent dimensional stability and physical properties under varying conditions of moisture, temperature, and the like, in contrast to conventional paper and polymer film substrates.
  • the use of microcellular foam materials in the articles of the invention can provide economies of manufacture of those articles, as compared to articles which include polymer films. For example, foam sheets can require less polymer starting material than unfoamed polymer films.
  • the physical properties of the articles of the invention typically are not substantially weakened or decreased, as compared to the material content of the product . Indeed, in some cases, the articles of the invention can exhibit an enhancement of physical properties. For example, the articles of the invention can exhibit excellent flexibility, strength, toughness, lay-flat, and die cuttability.
  • the surface topography of the microcellular foam materials can be readily modified in a controlled manner, even on extremely small scales, to impart positionability and/or repositionability to an adhesive layer applied thereto.
  • the microcellular foam materials can have smooth surfaces.
  • the surfaces of the microcellular foam materials are more readily modified to provide the desired topography, without the problems associated with defects in the surface.
  • extrusion rolls are not required for the production of these materials, thereby eliminating the problems associated with providing and maintaining an extrusion roll with a specific surface configuration.
  • structuring the surface of the articles of the invention can provide even greater dimensional stability to products which include the foam materials as a component .
  • a composite sheet material is provided.
  • the composite sheet material includes a substrate, an adhesive layer adhered to a surface of the substrate, and a release liner sheet releasably adhered to the adhesive layer. At least one surface of the adhesive layer is topographically modified, preferably to include a plurality of adhesive pegs projecting above the adhesive surface.
  • the release liner sheet includes a sheet of microcellular foam material having release properties on a surface thereof.
  • the release liner sheet also includes a plurality of spaced-apart depressions distributed across the surface adjacent the adhesive layer, and in which at least some of the adhesive pegs are located.
  • the microcellular foam material includes a plurality of cells distributed throughout the sheet with a cell density from about 10 9 to about 10 15 cells per cubic centimeter of each sheet.
  • the foamed sheet also preferably has a density from about 0.1 to about 0.95 grams per cubic centimeter and a thickness from about 0.5 to about 100 mils.
  • a release material is provided on a surface on the microcellular foamed sheet.
  • the release material can include any of the types of agents known in the art which provide release properties, such as fluoropolymers, silicones, chromium complexes modified long chain fatty acids, and the like.
  • the release material includes a curable silicone release agent .
  • the substrate of the composite sheet materials can be selected from any of the types of substrates known in the art, including polymeric substrates, cellulosic substrates, metal foils, metallized paper, metallized film, and substrates including both polymeric and cellulosic components, for example, sheets formed of a mixture of synthetic and cellulosic staple fibers.
  • the substrate can also be a second sheet of microcellular foam material as described above.
  • the adhesive preferably is a pressure sensitive adhesive.
  • a release liner sheet is provided as described above, i.e., a sheet of microcellular foam material having a plurality of cells distributed substantially throughout the sheet, the cell density of the cells lying in a range from about 10 9 to about 10 15 cells per cubic centimeter, the average size of the cells being less than about 10 microns; and a release material on a surface of the sheet of microcellular foam material.
  • the release liner sheet also includes a plurality of spaced-apart depressions.
  • a face sheet in yet another embodiment, includes a substrate formed of a sheet of microcellular foam material as described above having an adhesive on a front surface thereof.
  • the adhesive is preferably a pressure sensitive adhesive.
  • At least one surface of the adhesive layer is topographically modified, preferably to include a plurality of adhesive pegs projecting above the adhesive surface.
  • a rear surface of the substrate opposite the adhesive layer is receptive to printed indicia.
  • the present invention further provides label stock.
  • the label stock includes face stock of the invention as described above (i.e., a sheet of microcellular foam material having a topographically modified adhesive layer on a surface thereof) in combination with a release liner.
  • the release liner is releasably adhered to a surface of the adhesive layer opposite the foam sheet material.
  • the release liner can be selected from any of the release liner materials known in the art.
  • the release liner may also includes a sheet of microcellular foam material as described above in combination with a release material on a surface thereof.
  • the present invention also includes processes for making the composite sheet materials, release liner sheets, face stock and label stock of the invention.
  • Microcellular foam sheet components may prepared as known in the art by supplying a supercritical fluid to the polymer material to be foamed.
  • the supercritical fluid saturates the polymer to form an effectively saturated solution of the fluid and the polymer.
  • the fluid/polymer solution contains a sufficient amount of supercritical fluid at a suitable temperature and pressure
  • the temperature and/or pressure of the fluid/polymer system is rapidly changed to induce a thermodynamic instability and a foamed polymer is produced.
  • the foamed polymer can then be directed to additional manufacturing steps to produce the various articles of the invention which incorporate the foam materials as a component.
  • Figure 1 is a schematic perspective view showing a composite sheet material in accordance with the present invention with the respective layers of the composite sheet material being exposed for clarity of illustration;
  • Figure 2 is a cross -sectional view of the composite sheet material taken along line 2-2 of Figure 1 and illustrates a release liner sheet in accordance with the present invention
  • Figure 2A is an enlarged cross-sectional view of an adhesive projection illustrated in Figure 1;
  • Figure 3 is a schematic perspective view showing a face sheet material in accordance with the present invention with the respective layers of the face sheet material being exposed for clarity of illustration;
  • Figure 4 is a schematic perspective view of label stock in accordance with the present invention.
  • FIG 1 is a schematic perspective view of a composite sheet material designated generally as 10 in accordance with the present invention.
  • composite sheet material 10 includes a substrate 12, an adhesive layer 14 adhered to a surface of substrate 12, and a release liner sheet 16 overlying and releasably adhered to adhesive layer 14 such that adhesive layer 14 is sandwiched between substrate 12 and release liner sheet 16.
  • the surface topography of adhesive layer 14 is modified using suitable techniques, for example, as described in U.S. Patent Nos. 3,301,741; 5,296,277; 5,344,681; and 5 , 362 , 516 , the entire disclosure of each of which is hereby incorporated by reference .
  • suitable techniques for providing positionable or repositionable adhesives include, without limitation, applying the adhesive as a discontinuous pattern, distributing particles or beads in the adhesive layer (so that the beads are embedded completely within the adhesive or protrude from the surface) , topologically structuring or patterning the adhesive surface, and the like.
  • useful adhesive layers include at least one topologically microstructured adhesive surface 11 comprising a uniform distribution of adhesive pegs 13 projecting above adhesive surface 11.
  • Release liner sheet 16 includes uniformly spaced depressions 15 distributed across a surface adjacent adhesive layer 14, in which at least some of the pegs 13 are located.
  • Pegs 13 preferably have essentially flat tops that generally have a contact area of 1 to 25% of the total adhesive area and an average height ("h" of Figure 2A) of at least 15 ⁇ m, with a maximum height of 200 ⁇ m, preferably 150 ⁇ m, and more preferably 50 ⁇ m.
  • the height of individual pegs can vary, but preferably the height variations are randomly distributed so that a number of shorter, or higher, pegs are not grouped together .
  • the height of the pegs 13 is substantially uniform, in certain applications, it can be advantageous to provide variances in peg heights.
  • Pegs having different heights can be provided in mixed arrays, so that a given surface area of the adhesive surface 11 includes a distribution of pegs of different heights to impart varying adhesive positionability and/or repositionability in that region.
  • regions of adhesive surface 11 can include peg height gradients, i.e., a zone of pegs having an average height x, adjacent a zone of pegs having an average height y which is different from x.
  • Adhesive pegs 13 can be shaped such that the cross section of a peg taken in a plane parallel to the adhesive layer may be oval, circular, polygonal, rectangular, star-shaped, annular, irregular, and any combination thereof.
  • the inside angle (a) between the top and the sides of a peg is preferably no greater than 150°, more preferably between 80° and 135° (see Figure 2A) .
  • the angle between the base of a peg 13 and the adhesive surface 11 is not believed to be as critical as the upper inside angle and can be radiused.
  • Figure 1 illustrates a substantially uniform distribution of pegs across surface 11 of adhesive layer 14, the pegs may also be non-uniformly distributed across surface 11, for example, to provide a peg density gradient from top to bottom, side to side, convergent or divergent to the center of the article, etc. Further, pegs 13 could also project outwardly from a surface 17 of adhesive layer 14 opposite surface 11, and into substrate 12, or both surface 11 and surface 17 can be topographically structured or modified.
  • the spacing of pegs 13 can also vary, depending the adhesive properties desired for adhesive layer 14.
  • the pegs are spaced apart to provide a contact surface of the pegs of 1 to 25% of the total surface area of the adhesive layer, and a planar adhesive surface area between the pegs of greater than about 30% of the total adhesive layer.
  • the adhesive pegs can include the same adhesive material as the underlying adhesive layer.
  • the pegs can be a composite of adhesive and one or more beads, with the beads being substantially covered by adhesive.
  • the topologically microstructured adhesive surface can include a combination of adhesive only and composite pegs.
  • the beads are preferably covered or encompassed by adhesive, a portion of the beads can be above or below the surface and not covered by the adhesive. When present the beads can range in size, and further a mixture of bead sizes can be used.
  • Substrate 12 can be any of the types of substrates as known in the art, including, without limitation, polymeric substrates, such as polymer films (including metallized films) , polymer foams, sheets formed of synthetic staple fibers and/or filaments, and the like; cellulosic substrates, such as paper substrates (including metallized paper), woven, knit, netted or nonwoven fabric substrates formed of natural fibers and/or filaments, and the like; substrates including both polymeric and cellulosic components, for example, sheets formed of a blend or mixture of synthetic and cellulosic staple fibers and/or filaments; metal foils; and the like.
  • polymeric substrates such as polymer films (including metallized films) , polymer foams, sheets formed of synthetic staple fibers and/or filaments, and the like
  • cellulosic substrates such as paper substrates (including metallized paper), woven, knit, netted or nonwoven fabric substrates formed of natural fibers and/or filaments, and the like
  • Adhesive layer 14 can be formed of various suitable conventional adhesives known in the art, preferably a pressure sensitive adhesive.
  • Pressure sensitive adhesives in dry form are typically aggressively and permanently tacky at room temperature (e.g., from about 15 to about 25°C) and firmly adhere to a variety of surfaces upon contact without the need for more than manual pressure .
  • Such adhesives typically do not require activation by water, solvent or heat to exert a strong adhesive holding force towards materials such as paper, glass, plastics, wood, and metals .
  • Exemplary pressure sensitive adhesives include rubber-resin materials, polyolefins, acrylics, polyurethanes, polyesters, polyamides, and silicones.
  • the pressure sensitive adhesive may be solvent- coatable, hot-melt coatable, radiation curable (for example, by electron beam or ultraviolet radiation) , and water based emulsion type adhesives, all as well known in the art.
  • pressure sensitive adhesives include polyolefin-based polymers and copolymers, such as ethylene vinyl acetate copolymers; acrylic-based adhesives, such as isooctyl acrylate/acrylic acid copolymers and tackified acrylate copolymers; tackified rubber-based adhesives, such as tackified styrene-isoprene-styrene block copolymers, tackified styrene-butadiene-styrene block copolymers and nitrile rubbers, such as acrylonitrile-butadiene; and silicone-based adhesives, such as polysiloxanes .
  • Non-pressure sensitive adhesives such as thermally activated adhesives, solvent activated adhesives, and the like can also be used.
  • the adhesive may be substantially non-tacky at room temperature if it becomes tacky at an elevated temperature at which it is intended to be applied. Alternatively, the adhesive may be nontacky to the touch but aggressively cohesive with other substrates .
  • Adhesive layer 14 can be a single layer of a suitable adhesive material; alternatively, adhesive layer 14 can include multiple layers of adhesive materials. Adhesive layer 14 can also be a substantially continuous or discontinuous layer.
  • Release liner sheet 16 of the invention includes a support layer 18 and a release layer 20.
  • support layer 18 is a sheet of microcellular foamed material which includes a plurality of cells distributed substantially throughout the sheet. Further, the cell density of the cells in the sheet is from about 10 9 to about 10 15 cells per cubic centimeter of the sheet. Still further, the average size of the cells of the microcellular foam material 18 is less than about 10 microns, and preferably less than about 5 microns and, more preferably, less than about 1 micron.
  • the foam materials have the capability of providing a wide range of void fraction percentages from very high void fractions (low material densities) up to 90%, or more, to very low void fractions (high material densities) down to 20% or less.
  • foam sheet 18 has a density from about 0.10 to about 0.95, preferably about 0.3 to 0.7, grams per cubic centimeter (g/cc) , and a thickness from about 0.5 to about 100 mils, preferably about 1 to 50 mils, more preferably about 2 to 20 mils.
  • the surface of the sheet of microcellular foam material can be smooth or patterned.
  • Microcellular foam materials useful in accordance with the present invention are known in the art, and are described in, for example, U.S. Patent Nos. 5,334,356; 5,158,986; 5,034,171; 5,160,674; and 4,473,665, the entire disclosure of each of which is incorporated herein by reference. Illustrative techniques for the manufacture of microcellular foam materials and products of the invention incorporating the same are described in more detail below.
  • the microcellular foam materials are formed by using supercritical fluids, e.g., gases in their supercritical state, as a foaming agent in a polymeric material.
  • supercritical fluids include carbon dioxide (C0 2 ) , nitrogen, argon, helium, and the like in their supercritical state.
  • the supercritical fluid saturates the polymer to form a saturated solution of the fluid and the polymer at a first pressure and temperature.
  • the temperature and/or pressure of the fluid/polymer system is rapidly changed to induce a thermodynamic instability and a foamed polymer is produced.
  • the resulting foamed material can achieve a cell density of several hundred trillions of voids per cubic centimeter and an average void or cell size of less than 10 microns, in some cases less than 5, and still further in some cases less than 1 micron.
  • thermoplastic polymers capable of being foamed in accordance with the invention are preferably thermoplastic polymers, including both amorphous and semi-crystalline polymers.
  • thermoplastic polymers which can be cross-linked upon exposure to electromagnetic radiation (ultraviolet, electron beam, and gamma radiation) can also be used.
  • Exemplary thermoplastic polymers include, but are not limited to, polyolefins, such as polyethylene, polypropylene, polymethylpentene, polyolefins based on metallocene or single site catalysts, and copolymers thereof; vinyl polymers and copolymers, such as polyvinylchloride
  • thermoplastic polymer polystyrene, including syndiotactic polystyrene, and the like; acrylate polymers such as polymers and copolymers of acrylic acid and methacrylic acid and their amides, esters, salts and corresponding nitriles; polyamides; polyesters and copolyesters; polycarbonates; polycycloalkenes; copolymers of carbon dioxide and ethylene; polyamideimides; polyether ether ketones; and blends, alloys, copolymers, and grafted copolymers of these and other thermoplastic polymers, such as acrylonitrile-butadienestyrene (ABS) .
  • the thermoplastic polymer is selected based upon the desired physical and chemical properties of the resultant microcellular foam material.
  • Suitable thermoplastic materials also include thermoplastic polymers modified to impart release properties thereto.
  • a suitable thermoplastic polymer can be blended or copolymerized with an appropriate release material .
  • the resultant blend or copolymer can be used as the majority component of the foam sheet, or as a blending or alloying component in combination with other thermoplastic materials.
  • Thermoplastic modifying agents capable of imparting release properties include siloxanes, such as, but not limited to, polydimethyl siloxane, which can migrate or bloom to the surface of a substrate to provide release properties thereto.
  • Suitable copolymers include polyolefin (such as polyethylene) /polydimethyl siloxane copolymers, which include polyolefin as the majority component (80 to 99% polyolefin) .
  • the microcellular foam material is a polyolefin foam material formed by using carbon dioxide at supercritical conditions (i.e., above about 1,100 pounds per square inch (psi) and 39°C) .
  • Various additives, pigments, dispersing aids, adhesion promoters, lubricants, fillers, antioxidants , and the like may be added to the thermoplastic polymer prior to foaming.
  • the polymer can be blended with fillers such as talc, calcium carbonate, or other fillers prior to foaming.
  • Release layer 20 can include any of the types of agents known in the art which impart release properties to a substrate.
  • release layer 20 can be a coating of a release agent, such as a fluoropolymer, silicone, chromium complexes of long chain fatty acids and the like.
  • release agents are cured by any of several ways, such as by heat, by electromagnetic radiation, such as ultraviolet (UV) , electron beam, and the like, by moisture, and the like, as known in the art.
  • Release layer 20 can also be cured by evaporative processes as known in the art, i.e., dried to remove solvent.
  • Exemplary release agents include SYL-OFF 294® with Dow CORNING ® 176 catalyst, commercially available from Dow Corning; UV9315 with UV9310C catalyst, commercially available from General Electric Silicones; and Quilon, commercial available from E.I. duPont . Corona treatment can advantageously be used to promote adhesion of the release agent to the surface of sheet 18.
  • Release layer 18 has a thickness sufficient to impart the desired release properties of the release liner sheet 16 of the invention, for example, 30 to about 3000 nanometers thick.
  • a surface of foam material 18 of release liner 16 opposite release layer 20 advantageously is receptive to printed indicia.
  • Corona treatment can also be used to promote adhesion of printed indicia to a surface of sheet 18. This can be useful in applications wherein the release liner sheet is branded or labeled, for example, to indicate a source of labels produced therefrom, as described below.
  • Face stock materials are known in the art and generally can be described as any of the types of sheet materials or substrates known in the art with an adhesive layer on a surface thereof, which can be mounted or releasably adhered to a release liner.
  • face stock 30 includes a supporting or carrier substrate 32, an adhesive layer 34 overlying and adhered to substrate 32, and a plurality of adhesive pegs 33, as described above, projecting above adhesive surface 35.
  • a surface 37 of adhesive layer 34 opposite surface 35 can also be topographically modified to provide pegs projecting outwardly from surface 37 and into substrate 32.
  • substrate 32 is a sheet of microcellular foam material as described above, i.e., having a cell density from about 10 9 to about 10 15 cells per cubic centimeter, an average cell size of less than about 10 microns, a density from about 0.10 to about 0.95 g/cc, and a thickness from about 0.5 to about 100 mils.
  • Adhesive layer 34 can be any of the types of adhesive layers as described above, and preferably is a pressure sensitive adhesive layer.
  • a surface of substrate 32 of face stock 30 opposite adhesive layer 34 is rendered receptive to printed indicia, i.e., inks.
  • Printed . indicia can be applied to the surface of substrate 32 prior to or subsequent to its use, for example, prior to or subsequent to application of the face sheet to a substrate surface.
  • the surface can also be embossed, colored, metallized or otherwise decorated.
  • the surface of substrate 32 can be rendered receptive to printed indicia using techniques known in the art, such as corona treatment of the substrate surface, application of an additional layer to the substrate surface which is receptive to printed indicia, and the like.
  • Face sheet 30 can be used in combination with a release liner sheet releasably adhered to adhesive layer 34 to form a composite structure, such as that illustrated in Figure 1.
  • the composite structure resulting from the combination of face stock 30 with a release liner sheet is particularly useful as label stock, i.e., a sheet material from which a plurality of individual labels having a predetermined size and shape can be provided.
  • label stock i.e., a sheet material from which a plurality of individual labels having a predetermined size and shape can be provided.
  • any of the types of release liner sheets known in the art can be used in combination with face stock 30 to form label stock.
  • the release liner sheet can be, for example, a release liner sheet 16 as illustrated in Figure 2, i.e., a support layer 18 formed of a sheet of microcellular foamed material as described above in combination with a release layer 20, wherein the release layer is disposed between adhesive layer 34 and support layer 18.
  • Label stock in accordance with the present invention can include other release liners as known in the art in combination with face stock 30.
  • Exemplary release liner materials include, but are not limited to, polymer films, optionally coated with a silicone or other release agent; paper sheets advantageously having a polymer (such as polyethylene) coating covered with a release agent such as silicone; and the like.
  • Figure 4 illustrates schematically one such use of label stock in accordance with the present invention, namely, label stock useful in the graphic arts industry.
  • Label stock 40 is formed from a composite sheet material, such as that illustrated in Figure 1 (i.e., includes a substrate 12, an adhesive layer 14 adhered to a surface of substrate 12 and including a plurality of pegs 13 projecting above an adhesive surface 11, and a release liner sheet 16 overlying and releasably adhered to adhesive layer 14 such that adhesive layer 14 is sandwiched between substrate 12 and release liner sheet 16)
  • a design or indicia 42 is printed onto the front surface of substrate 12, such as a vinyl sheet material, opposite adhesive layer 14 of the composite material of Figure 1.
  • Substrate 12 can be cut or perforated about the perimeter of the design to allow the design 42 and adhesive on a rear surface thereof to be easily pulled away and removed from the release liner material, as indicated.
  • the design and adhesive on a rear surface thereof can be applied to a surface as desired.
  • the label stock can also be in other forms, for example, as a supply of roll labels, sheet labels, and the like.
  • microcellular foam materials as support or carrier substrates in the release liner sheets, face sheets, and label stock of the present invention can result in a variety of desirable characteristics. Because a foamed material is used as a component in place of polymer films, paper substrates, and the like, manufacturing costs, such as the cost of resin, can be reduced.
  • the microcellular foam materials can also impart physical properties comparable to and in some cases better than the properties exhibited by products which incorporate polymer films, paper sheets, etc, i.e., can have excellent flexibility, strength, toughness, lay- flat, and die cuttability.
  • the articles of the invention are substantially dimensionally stable upon exposure to changes in moisture, temperature, and the like, thus rendering the articles particularly useful in graphic arts applications.
  • microcellular foam materials in the articles of the invention provide other advantages.
  • the surface of a paper substrate is inherently rough, which in turn can result in surface defects, or micropitting, in articles which include the paper substrate.
  • microcellular foam materials have substantially flat or smooth surfaces with minimal or no surface defects.
  • the microcellular foam surface can be readily structured in a controlled manner to impart the desired surface topography thereto.
  • patterning or microstructuring the surface of the adhesive layer can provide even greater dimensional stability to the products incorporating the same as a component.
  • microcellular foam sheet materials as a components in any of the types of products which typically include a support or carrier substrate.
  • the microcellular foam sheet materials are also useful as components in liner- less labels, as known in the art.
  • the microcellular foam materials used in this and other aspects of the invention can be prepared using batch or continuous processing techniques as known in the art, for example, those techniques described in U.S. Patent Nos. 5,334,356; 5,158,986; 5,034,171; 5,160,674; and 4 , 473 , 665 , referenced above .
  • the microcellular foam material and the various products of the invention which incorporate the foam material are manufactured in a continuous process.
  • the microcellular foam sheet materials can be formed using supercritical fluids, e.g., gases in their supercritical state.
  • a supercritical fluid for example, carbon dioxide, above about 1,100 pounds per square inch (psi) and 39 °C
  • psi pounds per square inch
  • 39 °C a supercritical fluid
  • Sufficient supercritical carbon dioxide is supplied so as to form a molten fluid/polymer material in which the polymer is effectively saturated with supercritical fluid.
  • the molten fluid/polymer material exits the extruder barrel to a sheet die, which forms a sheet of the fluid/polymer material.
  • This material is supplied to a pressurized chamber. The pressure in the chamber is maintained at a level lower than that at the extruder barrel exit. As the pressure drops upon entering of the fluid/polymer material into the chamber, cell nucleation occurs within the material.
  • the fluid/polymer material can then be supplied to foaming heaters to achieve cell expansion and completion of the foaming process.
  • the foamed polymer material can be annealed, e.g., for crystallization of the foamed polymer if desired by annealing heaters.
  • a series of pressure chambers can be used, the pressure within each of which is selected to subject the sheet material to a pressure differential as the sheet material passes from one chamber to the next .
  • Cell expansion occurs as polymer material exits one chamber having a first pressure into the other chamber which is set to an even lower pressure chamber, e.g., at ambient pressure, so that the completely foamed polymer material is obtained at that point.
  • foaming i.e., cell nucleation and cell expansion
  • the foam sheet material can be stored in roll form for subsequent use.
  • the foamed sheet material can be directed to additional manufacturing steps, such as the production of composite sheet materials, release liners, face stock, and label stock of the invention.
  • a release material can be applied to a surface of the foamed sheet material using conventional apparatus and techniques, and subsequently cured, as needed.
  • a release agent can be mixed or copolymerized with the polymer prior to foaming, and the resultant foamed sheet material subjected to conditions sufficient to cause the release agent to bloom or migrate to a surface of the microcellular foam material to impart release properties to a surface thereof .
  • the resultant release liner sheet can be stored in roll form for subsequent use, or alternatively, thereafter directed to additional manufacturing steps, such as the manufacture of composite sheet materials of the invention.
  • an adhesive preferably a pressure sensitive adhesive, can be deposited onto the surface of the release liner sheet having release properties.
  • the release liner/adhesive structure can thereafter be directed into face-to-face relationship with a suitable substrate to form a release liner/adhesive/substrate structure.
  • the substrate can be any of the substrates referenced above, including a second sheet of microcellular foam material.
  • This structure can be then directed through a suitable pressure nip, such as that formed by two rolls, to press the layers together for good interply adhesion.
  • the resultant composite sheet material can be stored in roll form, or directed to additional in-line processing, for example, to manufacture label stock therefrom using known techniques and apparatus.
  • a coating of an adhesive can be directly applied to an upper surface of microcellular foam material using conventional techniques and apparatus.
  • adhesive is not directly applied to the substrate but rather is applied using adhesive transfer techniques as described above, i.e., by applying adhesive first to a release liner sheet, which is then joined to the substrate.
  • At least one surface of an adhesive layer of the articles of the invention can be topologically modified using suitable techniques, for example, by applying the adhesive as a discontinuous pattern to the substrate surface, distributing particles or beads in the adhesive layer (so that the beads are embedded completely within the adhesive or protrude from the surface) , topologically structuring or patterning the adhesive surface, and the like.
  • the adhesive layers of the articles of the invention are topographically modified using the techniques described in U.S. Patent Nos. 3,301,741; 5,296,277; 5,344,681; and 5,362,516, referenced above.
  • an adhesive layer of the articles of the invention is patterned or modified by coating an adhesive onto a sheet of microcellular foam material which has been embossed or otherwise provided with a plurality of depressions distributed across the surface.
  • release properties are imparted to the surface of the microcellular foam material prior to application of the adhesive.
  • an adhesive can be directly coated onto the release surface of a microstructured sheet material in which small depressions have been previously filled with beads and optionally a functionally sufficient amount of polymeric binder.
  • the composite structures can be formed with a first pass coating of an adhesive/bead slurry, following by an adhesive only coating. The release liner/adhesive structure can then be combined with a suitable substrate, as described above, to form a composite sheet material.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Adhesive Tapes (AREA)
  • Laminated Bodies (AREA)

Abstract

L'invention concerne une gamme d'articles renfermant une feuille en mousse microcellulaire et une couche adhésive à topographie modifiée, à savoir par exemple: feuille de revêtement arrachable, faces ou étiquettes adhésives et autres. La densité cellulaire de la feuille en mousse microcellulaire oscille environ entre 10?9 et 1015¿ cellules/cm3, et la taille des cellules est inférieure à environ 10 microns. On décrit des procédés pour la fabrication de ces articles en matériau à mousse microcellulaire.
PCT/US1997/010979 1996-07-03 1997-06-24 Article en mousse microcellulaire avec couche adhesive a topographie modifiee WO1998000469A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU35017/97A AU3501797A (en) 1996-07-03 1997-06-24 Articles including microcellular foam materials and topographically modified adhesive layers as components thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US67555796A 1996-07-03 1996-07-03
US08/675,557 1996-07-03

Publications (1)

Publication Number Publication Date
WO1998000469A1 true WO1998000469A1 (fr) 1998-01-08

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PCT/US1997/010979 WO1998000469A1 (fr) 1996-07-03 1997-06-24 Article en mousse microcellulaire avec couche adhesive a topographie modifiee

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AU (1) AU3501797A (fr)
WO (1) WO1998000469A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999004968A2 (fr) * 1997-07-24 1999-02-04 Trexel, Inc. Stratification d'articles micro-cellulaires
WO2000007046A1 (fr) * 1998-07-31 2000-02-10 Minnesota Mining And Manufacturing Company Films a plusieurs couches postformables et procedes de formage
US9588270B2 (en) 1998-01-13 2017-03-07 3M Innovative Properties Company Post-formable multilayer optical films and methods of forming

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH645845A5 (fr) * 1981-03-23 1984-10-31 Crowell Corp Feuille laminee pour l'emballage de produits sensibles a la corrosion.
EP0191003A1 (fr) * 1985-01-28 1986-08-13 Fagerdala Industri Ab Procédé de fabrication de rubans adhésifs, sensibles à la pression, découpés longitudinalement et articles analogues
US5296277A (en) * 1992-06-26 1994-03-22 Minnesota Mining And Manufacturing Company Positionable and repositionable adhesive articles

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH645845A5 (fr) * 1981-03-23 1984-10-31 Crowell Corp Feuille laminee pour l'emballage de produits sensibles a la corrosion.
EP0191003A1 (fr) * 1985-01-28 1986-08-13 Fagerdala Industri Ab Procédé de fabrication de rubans adhésifs, sensibles à la pression, découpés longitudinalement et articles analogues
US5296277A (en) * 1992-06-26 1994-03-22 Minnesota Mining And Manufacturing Company Positionable and repositionable adhesive articles

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999004968A2 (fr) * 1997-07-24 1999-02-04 Trexel, Inc. Stratification d'articles micro-cellulaires
WO1999004968A3 (fr) * 1997-07-24 1999-04-08 Trexel Inc Stratification d'articles micro-cellulaires
US6235380B1 (en) 1997-07-24 2001-05-22 Trexel, Inc. Lamination of microcellular articles
US9588270B2 (en) 1998-01-13 2017-03-07 3M Innovative Properties Company Post-formable multilayer optical films and methods of forming
WO2000007046A1 (fr) * 1998-07-31 2000-02-10 Minnesota Mining And Manufacturing Company Films a plusieurs couches postformables et procedes de formage

Also Published As

Publication number Publication date
AU3501797A (en) 1998-01-21

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