Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F13/00—Bandages or dressings; Absorbent pads
  • A61F13/02—Adhesive plasters or dressings
  • A61F13/0276—Apparatus or processes for manufacturing adhesive dressings or bandages
• • 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
  • C09J7/201—Adhesives in the form of films or foils characterised by their carriers characterised by the release coating composition on the carrier layer
• • 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
  • C09J7/21—Paper; Textile fabrics
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M23/00—Treatment of fibres, threads, yarns, fabrics or fibrous goods made from such materials, characterised by the process
  • D06M23/04—Processes in which the treating agent is applied in the form of a foam
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
  • D06N3/0043—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by their foraminous structure; Characteristics of the foamed layer or of cellular layers
  • D06N3/0045—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by their foraminous structure; Characteristics of the foamed layer or of cellular layers obtained by applying a ready-made foam layer; obtained by compressing, crinkling or crushing a foam layer, e.g. Kaschierverfahren für Schaumschicht
• • 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
  • C09J2301/00—Additional features of adhesives in the form of films or foils
  • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
  • C09J2301/302—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• • 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
  • C09J2400/00—Presence of inorganic and organic materials
  • C09J2400/20—Presence of organic materials
  • C09J2400/26—Presence of textile or fabric
  • C09J2400/263—Presence of textile or fabric in the substrate

Definitions

• This invention generally relates to a process for applying a foamed coating to a web and particularly relates to a process for applying a foamed release coating to a porous, pressure sensitive adhesive medical tape backing.
• Pressure sensitive adhesive tapes for medical purposes place special demands on the components used to make these tapes.
• the components making up the tape must be accommodated by the user, i.e., biocompatible.
• the adhesives and coatings must not be undesirably transferred to the user during use.
• stringent demands are placed on the materials and processes used to make such tapes.
• Pressure sensitive adhesive tapes are typically made from polymeric films, paper, woven fabrics or nonwoven tape backings coated with a pressure sensitive adhesive on one side or surface of the backing and with a release coating on the other side of the backing.
• the release coating allows the coated tape backing to be rolled onto itself and prevents the transfer of the adhesive on the tape from one layer of tape in the roll to an adjacent layer.
• release coatings have been used for this particular purpose.
• typical release coatings were dissolved in a volatile organic solvent to give a mixture or solution that was then applied to one side or surface of a tape backing using a variety of methods.
• mixtures or solutions of release coatings and volatile solvents have been applied to tape backings using rollers, dips, knife coaters or other common application apparatus.
• the problems caused by using mixtures or solutions of release coatings and volatile organic solvents has prompted the development of water-based release coatings.
• U.S. Patent 4,973,513 reports that a water-based release coating may be applied to a pressure sensitive adhesive tape using conventional coating processes such as wire-wound rod, reverse roll, air knife, direct and offset gravure trailing blade, print bond or spray coating.
• U.S. Patent 5,089,296 reports that release coatings may be foamed and then applied to paper and other substrates.
• the foams are slow breaking and require an external force such a mechanical compression or vacuum to collapse. It is also reported that control of the collapse of the foam is important because the foams rapidly penetrate and impregnate surfaces after the foam has collapsed.
• the release coating composition must not be fast wetting in order to insure that the release coating remains on the surface of the substrate. This patent indicates that fast breaking foams are not acceptable for coating processes because migration of the release coating into a tape backing would be expected.
• the present invention provides a process for applying a foamed coating to a medical pressure sensitive adhesive tape.
• the present process may be used to apply a thin, uniform coating, such as a release coating or a low adhesion backsize, to a porous, pressure sensitive tape backing and includes the steps of i) forming a porous tape backing having a least one surface from polymeric fibers, ii) forming a foam of an aqueous emulsion to give a foamed emulsion, wherein the foamed emulsion is prepared by mixing water, an aqueous emulsion, and a surfactant to give a foam that collapses immediately when the foamed emulsion is applied to the tape backing, iii) applying the foamed emulsion to at least one surface of the tape backing to give a coated tape backing, and iv) coating the tape backing with a pressure sensitive adhesive.
• a thin, uniform coating such as a release coating or a low adhesion backsize
• Suitable tape backings include both woven and nonwoven fabrics, webs containing elastomeric fibers or yarns, and laminated or composite porous backings.
• the present invention also includes a process in which the pressure sensitive adhesive is applied to the tape backing before the application of the release coating.
• the process would include the steps of i) forming a porous tape backing having at least one surface from polymeric fibers, ii) coating at least one surface of the tape backing with a pressure sensitive adhesive, iii) forming a foam of a release coating to give a foamed composition, wherein the foam is prepared by mixing water, the release coating, and a surfactant to give a fast breaking foam composition that collapses immediately when the foam composition is applied to the porous tape backing, and iv) applying the foamed emulsion to one surface of the porous tape backing containing the pressure sensitive adhesive to give a coated pressure sensitive adhesive tape.
• the present process therefore may be reliably performed with much simpler apparatus than previously reported which avoids critical or complicated foam application, spreading or breaking equipment, reduces the amount of release coating which must be applied to the backing, removes potential for mechanical failure, allows high tape backing throughput and ensures proper adhesive attachment to the tape backing.
• the present process may be used to produce pressure sensitive adhesive tapes which are capable of passing the stringent requirements associated with medical pressure sensitive adhesive tapes.
• the present process provides pressure sensitive adhesive tapes which may be used in a variety of medical applications.
• a fast breaking foam of a natural rubber latex may be used to apply a thin, uniform coating of an aqueous natural rubber latex emulsion to a woven or nonwoven elastomeric backing.
• This process is essentially the same as the process for applying a release coating to a tape backing except that a porous elastomeric material is used as the backing.
• This process includes the steps of i) forming a porous, elastomeric backing having a least one surface, ii) forming a foam of an aqueous natural rubber latex emulsion to give a foamed emulsion, wherein the foamed emulsion is prepared by mixing water, natural rubber latex, and a surfactant to give a foam that collapses immediately when the foam is applied to the porous, elastomeric backing, iii) applying the foamed emulsion to both surfaces of the elastomeric backing to give a coated backing, and iv) drying the coated backing.
• Figure 1 is a schematic representation of a tape coating process in which a fast breaking foam is applied to a tape backing. No mechanical apparatus or externally applied force is used to break the fast breaking foam.
• Figure 2 is a schematic representation of a tape coating process in which a slow breaking foam is applied to a tape backing and the applied foam is then mechanically broken on the surface of the backing.
• Figure 3 is a schematic representation of a tape coating process which applies a foamed natural rubber latex to an elastomeric backing.
• Figure 4 is a schematic representation of a tape coating process which applies a foamed release coating and a transfer adhesive to a tape (with removal of the liner after application of the transfer adhesive).
• the process of this invention is readily adapted to typical processes used to make pressure sensitive adhesive tape.
• Some typical processes currently used to make pressure sensitive adhesive tapes include forming a web from a fibrous material and then adhering the fibers of the web together with a wet binder. The wet web is then dried at elevated temperatures to give a tape backing. A release agent is then applied to one surface of the tape backing and the coated backing is again dried. Finally, a pressure sensitive adhesive is applied to the surface of the tape backing which is not coated with the release agent, the tape backing is again dried and then the tape is wound into rolls.
• Figure 1 is a schematic illustration of a tape coating process of the present invention in which a fast breaking foam of a low adhesion backsize emulsion is applied to a binder wet web tape backing.
• a backing 10 is led from a nonwoven maker (not shown) and passes between binder application rollers 12 and 14. Binder is applied from station 13 by doctor blade 11. The backing proceeds to a foam coating station at which a fast breaking foam 16 is applied from a foam die 18. The applied foam coating 16 is dried by oven 20.
• FIG. 2 is a schematic illustration of a known tape coating process in which a slow breaking foam of a low adhesion backsize emulsion is applied to a thermal bonded binder wet tape backing and the applied foam is then mechanically broken on the surface of the backing.
• a backing 22 is led from a nonwoven maker (not shown) between binder application rollers 24 and 26.
• Binder is applied from station 25 by doctor blade 27.
• the backing proceeds to a coating station at which a slow breaking foam 28 is applied from a foam die 29 and the foam is broken as the coated backing passes under a plastic knife edge spreader 21.
• the applied coating 28 is dried by oven 20.
• FIG 3 is a schematic illustration of a tape coating process of the present invention in which a foamed natural rubber latex is applied to an elastomeric backing.
• Elastic yarns 36 are led from supply spools 34 through combs 35 and then between pressure rollers 38 and 40 so that the elastic yarns will be placed between two layers of nonwoven backing 32 which are unrolled from supply rollers 30 A and 30B.
• the layered construction is carried between roller 42, which applies a noncohesive elastomer binder from coater 44, and roller 46 to foam dies 48 and 50 which apply natural rubber latex foam and then through oven 52 to dry the composite web 53.
• the dried web 53 is then directed through a pair of nip rollers 54 and 56 and through an oven 58 which is sufficiently hot to effect shirring and heat-setting as described in U.S. Patent 3,575,782 (Hansen) and then through a pair of nip rollers 60 and 62 and wound into a roll with the aid of a winder roller 72.
• FIG 4 is a schematic illustration of a tape coating process in which the process illustrated in Figure 3 applies a foamed low adhesion backsize emulsion from foam die 50 and is expanded by applying a transfer adhesive to the web 53 after it has exited oven 52, with subsequent removal of the transfer tape liner.
• the transfer adhesive on a liner 66 is supplied from roller 64 and the resulting laminate 67 is carried between nip rolls 54 and 56 with removal of liner 70 to roll 68 while web 59 is carried through oven 58 and wound into a roll.
• Nonwoven webs for use in preparation of porous tape backings are made in accordance with conventional methods known in the art, including wet laid methods, dry laid methods such as air layering and carding, and direct laid methods such as spunbonding and meltblowing.
• the nonwoven web is formed from synthetic or natural fibers selected according to the desired properties of the resulting web.
• textile fibers appropriate for use in the backing webs include polyester, polyolefin, polyamide, rayon, cotton, or the like.
• the nonwoven web may also incorporate reinforcing filaments, such as polyester, or shirring fibers such as LYCRA spandex yarns.
• the fibers are preferably coated with a water-based binder to give a suitable tape backing.
• binders include latexes incorporating acrylics, styrene/butadiene rubbers, vinyl acetate/ethylenes, vinyl acetate/acrylates, polyvinyl chloride, polyvinyl alcohols, polyurethanes and vinyl acetates.
• Such binders are typically applied to the fibers at 25-35 weight percent solids by any suitable coating method, including wire-wound rod, reverse roll, air knife, direct and offset gravure, trailing blade, print bond and spray coating methods.
• the binder is applied in amounts sufficient to provide the desired properties to the backing, typical amounts for different types of backings would be readily apparent to the skilled artisan in the nonwoven manufacturing field. For example, more binder may be applied to produce a stronger material, which is usually stiffer, of a similar construction.
• a water-based release coating is applied using the process of the present invention.
• the water-based release coating materials include polyethylenes, fluorochemicals, acrylates, silicones, vinyl copolymers and combinations of these polymers with other polymers.
• the release coating is a low adhesion backsize comprising poly(dimethyl siloxane) and acrylate polymers. Acceptable low adhesion backsizes are disclosed, for example, in U.S. Patent 4,728,571 (Clemens, et al.).
• a release coating is preferably mixed with more than about 0.5 weight percent of an anionic or nonionic surfactant.
• a preferred surfactant is an anionic surfactant such as TRITON GR-5M or a nonionic surfactant such as TRITON X-100 (both surfactants are available from Rohm and Haas Company, Philadelphia, PA).
• Typical blowing ratios for the foamed release coatings are from about 4 to 30.
• Preferred blow ratios for foaming a release coating are 20 to 30.
• Preferred blow ratios for foaming a natural rubber latex are 8 to 12.
• Suitable foams for use in the present invention may be prepared using conventional methods and apparatus.
• a foamed release coating or a foamed natural rubber latex may be prepared in a commercially available foamer such as a LESS SUPERFOAMER foaming apparatus (Latex Equipment Sales and Surface, Palton, GA).
• the SUPERFOAMER apparatus is particularly convenient because it is equipped to pump the foamed material under pressure directly to a foam die.
• the foam die provides a back pressure and an appropriate delivery rate of the foam.
• the foamed material is pumped to a foam die and then applied to the tape backing by the die.
• the amount of material which is coated onto the tape backing is controlled by the rate the material is pumped through the die.
• the rate is set to deliver a thin coating at a rate of less than about 4.0 g/m 2 of a dry release coating to the tape backing (measured as difference of the dry tape backing from the dry coated tape backing).
• the rate of delivery is about 0.5-1.5 g/m 2 .
• the rate of delivery for applying a thin coating of a dry rubber latex to a tape backing is about 5 to 7 g/m 2 per side.
• the foam die In addition to delivering the foam to the tape backing, the foam die also controls the uniformity of the foam applied across the width of the tape backing.
• a foam die which particularly applies a uniform coating from the die uses the foam emission nozzle described in U.S. Patent 4,655,056 (Zeiffer). This type of die is properly shaped to deliver a uniform flow of foam across the width of the tape backing and provides an edge-center-edge weight percent distribution of less than about plus or minus 8 weight percent.
• Other types of foam dies which are capable of delivering foam to a tape backing in such a controlled manner may be used in the present process.
• the coated tape backing is dried using any appropriate drying means.
• drying means that are conventional in the nonwoven textile arts include contact drying, circulating air ovens, impingement ovens and through-air ovens.
• the tape backing is dried in a circulating air oven at about 145-155°C for about one minute.
• the heat source is preferably located on the same side of the tape backing in the oven as the release coating, so that wicking of the release coating through the web is not encouraged by uneven drying. It is envisioned that on production scale equipment, the wet release coated tape backing will be conveyed to the drying oven about 0.5-10 seconds after application of the release coating.
• the coated tape backing may be wound in a roll for transportation for later application of an adhesive, or it may be conveyed directly to an adhesive coater, followed by slitting into individual tape rolls.
• adhesive may be applied as a transfer adhesive from a liner.
• the pressure sensitive adhesive that is applied to the nonwoven tape backing may be solvent-based, water based, or a hot melt adhesive.
• Suitable adhesives such as phenolic cured rubber based adhesives are disclosed in U.S. Patent 2,708,192 (Joesting et al.). Both water-based and solvent-based adhesives are disclosed in U.S. Patent RE 24,906 (Ulrich). Hot melt adhesives are disclosed, for example, in U.S. Patent 4,833,179 (Young et al.).
• a foamed natural rubber latex is applied to an elastomeric tape backing.
• Processes to prepare a porous, elastomeric backing are known in the art.
• an elastomeric self-adhering bandage is described in U.S. Patents 3,575,782 (Hansen) and 4,984,584 (Hansen et al.).
• elastic yarns are bonded between two layers of a nonwoven web with a natural rubber latex to provide a backing having good compression characteristics and cohesiveness or the ability to self adhere.
• a nonwoven web was prepared from a blend of 80 parts T-121 staple polyester fiber, 1.2 denier 38 mm polyethylene terephthalate available from Hoechst Celanese Corp., Charlotte, NC and 20 parts of 2 denier 38 mm type K-54 MELTY type binder fiber (a core-sheath fiber containing an oriented polyester core and a meltable polyester sheath also available from Hoechst Celanese Corp., Charlotte, NC) were processed in a Hergeth Random-Card machine (available from Hergeth Hollingsworth GMBH, Dulman, West Germany) utilizing conventional nonwoven web formation techniques to produce an approximately 35 g/m 2 basis weight nonwoven web.
• Hergeth Random-Card machine available from Hergeth Hollingsworth GMBH, Dulman, West Germany
• the nonwoven web was embossed using a heated calender and then was wet with 25 wt. % solids acrylic/vinyl acetate copolymer latex binder (available from National Starch Company, Bridgewater, NJ as 78-6283) to give nonwoven tape backing.
• the wet tape backing was treated with a foamed release agent.
• the foam was made by a LESS foaming apparatus (available from Latex Equipment Sales and Service, Palton, GA, as SUPERFOAMER model) from a 2 wt. % aqueous solution of water-based low adhesion vinyl silicone copolymer backsize (prepared as described in U.S.
• Patent 5,032,460 (Kantner et al.)) of 20/50/10/30 methyl acrylate/methyl methacrylate/methacrylic acid/mercapto dimethyl siloxane.
• the foam was applied using a knife edge type system of a straight edge of hard plastic sheeting 100 mils (2.54 mm) thick by 4 inches (10.2 cm) wide by 36 inches (91.4 cm) long.
• the foam covered backing was carried at 15 feet per minute (4.57 m/min) into and through an oven at 325-350 °F (163-177°C) and the dried backing web was wound onto a 3 inch (7.6 cm) core.
• the coated backing was then coated full width at 6.5 grains/24 in 2
• the rolls were found to unroll readily after aging for 2 days at 120°F (49°C) at 90% relative humidity.
• the adhesive attachment to the coated backing was not adequate because an adhesive residue was left on the skin when the medical tape was used.
• the amount of adhesive residue was more than about two times the adhesive residue when compared to a similar tape prepared by spraying the low adhesion backsize onto the backing as generally described in U.S. Patent 4,973,513 (Riedel et al.).
• the decrease in adhesive attachment to the backing is a result of low adhesion backsize penetration into the backing when the foam was mechanically broken on the backing surfacing using the plastic knife edge.
• Another tape backing was prepared from standard viscose processed rayon staple fibers (1.5 denier, 40 mm length, available from Courtaulds North America, Inc., New York, N.Y.) in a Hergeth Random-Card machine to produce an approximately 22 g/m 2 basis weight nonwoven backing.
• Using the apparatus of Figure 2 about 50 yards (45.7 m) of the rayon backing was either wet treated with various binders at 28 v -. % aqueous solids loading or treated with the binders at 28 wt. % aqueous solids and dried, and then was froth coated according to the procedure described above with a 2 wt. % solution of the low adhesion backsize containing a surfactant added (0.5 wt.
• % TRITON GR-5M available from Rohm and Haas Company, Philadelphia, PA.
• the line speed was 15 feet/minute (4.57 m/min) and the oven temperature was 340 °F (171 °C).
• Spreading was done by an idler arm or a wipe blade.
• Table 1 Specific processing conditions are listed in Table 1 below. After the listed tapes were coated and dried, they were aged for 2 days at 120°F (49°C) at 90% relative humidity. Roll unwind of the aged tapes was determined according to ASTM D-1000. The roll unwind was 450 g/2.54 cm and found to be unsatisfactory. In addition, the adhesive attachment was determined for the listed tapes and it was found that the adhesive residue was above acceptable levels for a medical adhesive tape.
• NS is a binder available from National Starch used in Example 1
• 3 4402 is styrene-butadiene rubber binder available from Unical Corp., Charlotte, NC as UC 4402
• Medical adhesive tapes were prepared according to the process generally described in Example 1 above except that no mechanical means were used to break or spread the foam after it was applied to a tape backing as illustrated schematically in Figure 1. More specifically, a rayon backing was prepared from 1.5 denier and 1-9/16 inch (3.97 cm) long fibers using the process described in Example 1. The web had a basis weight of 20 g/m 2 and was about 12 to 14 inches (30.5 to 35.6 cm) wide and was trimmed to 12 inches (30.5 cm) wide. It was coated at a speed of about 30 to 35 feet/minute (9.1 to 10.7 m/min) with a variety of binders as shown in Table 2 to a ratio of about 1 g of binder to 1 g of web fiber using suspensions of 26 wt.
• Example 1 % binder solids at pH 7.5 to 8.5. After the binder was coated on, the low adhesion backsize used in Example 1 was coated as a foam using the foamer described in Example 1 and a Gaston County 0.25 inch (0.635 cm) oriface parabolic die. The low adhesion backsize included 1.25 wt. % GR-5M surfactant and was applied at a 22: 1 blow ratio.
• HP-2931 Rohm and Haas
• a web of 12 g/m 2 thermally bonded polyethylene terephthalate fibers of web width 16 in (40.64 cm) was prepared according to the method described in Example 1 above.
• a noncohesive elastomer, H stretch V-43 (available from B.F. Goodrich Company, Akron, OH) was applied to two layers of the backing sandwiching a spandex elastomeric yarn to give an elastomeric tape backing as shown in Figure 3.
• Cohesive elastomer natural rubber latex (available from Goodyear Rubber Plantations Company, Akron, OH) was applied as a foam to both sides of the wet elastomeric tape backing at a blow ratio of 10: 1 and dried.
• the coated tape backing was subsequently slit using a conventional slitting apparatus into self wound rolls. The product exhibited a light cohesion to itself after foam coating of the natural rubber latex.
• a similar elastomeric adhesive tape was also prepared according to the following procedure.
• a coating of a low adhesion backsize was applied to one side of the noncohesive polyethylene terephthalate elastomeric tape backing described above using the process of the present invention from the LESS foaming apparatus of Example 1.
• the low adhesion backsize used was that used in Example 1 which had been foamed at a blender speed of 153 rpm, pump speed 15 rpm, air flow setting 20, air inlet setting 40 psi and back pressure 7 psi at a blow ratio of 22:1.
• the release coating process was carried out at 12 ft/min (3.66 m/min) line speed, the low adhesion backsize was applied at 2.0 g/m 2 at an application rate of about 140 g/min of low adhesion backsize emulsion (2% solids in water). Then, an acrylic acid-isooctyl acrylate (4:96 molar ratio) copolymeric transfer adhesive (as described in U.S. Patent RE 24,906) coated at 60 g/m 2 on a differential release liner (liner 2-80 BKG 157/99 AM available from Daubert Coated Products, Dixon, IL) was dry laminated from the coated liner onto the uncoated side of the elastomeric backing using conventional procedures.
• the resulting elastomeric adhesive tape had no cohesion to the nonfoam coated web.
• the rolls were tested for roll unwind according to ASTM D-1000 and found to have acceptable unwind of less than 350 g/2.54 cm.
• the rolls were also tested for adhesive anchorage according to residue left as described above and found to be satisfactory.
• Example 4 Cloth Backing Treated with Foamed Low Adhesion Backsize
• An acetate cloth fabric pressure sensitive adhesive tape was prepared according to the following procedure. A 25 m in length by 20 cm in width of the acetate fabric (style 180 x 48 plain weave available from Milliken & Company, LaGrange, Georgia) was coated on one side with an acrylic acid-isooctyl acrylate (4:96 molar ratio) copolymer adhesive in ethyl acetate solvent prepared as described in U.S. Patent RE 24906 (Ulrich) at a rate of 60 g/m 2 and dried in an air circulating oven.
• Example 1 Before entering the final oven drying stages a coating of low adhesion backsize was applied to the non-adhesive coated side of this backing using the process of the present invention from the LESS foaming apparatus of Example 1.
• the low adhesion backsize used was the vinyl silicone copolymer that was used in Example 1 which had been foamed at a blender speed of 153 rpm, pump speed of 15 rpm, air flow setting of 20, air flow setting of 40 psi and a back pressure of 7 psi and a blow ratio of 22:1.
• the coating process was carried out at 12 ft/min (3.66 meters) line speed, the low adhesion backsize was applied at a rate of 2.1 g/m 2 from about 140 g/min of low adhesion backsize emulsion (2% solids in water).
• the resulting adhesive tape rolls were tested for roll unwind according to ASTM D-1000 and found to have acceptable unwind of less than 350 g/2.54 cm.
• the rolls were also tested for adhesive anchorage according to residue left as described above in Example 2 and found to be satisfactory, i.e., to have a value below 2.5.

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• 1994
  • 1994-11-04 EP EP95900523A patent/EP0731678A1/en not_active Ceased
  • 1994-11-04 CN CN94194342A patent/CN1136271A/zh active Pending
  • 1994-11-04 WO PCT/US1994/012653 patent/WO1995015136A1/en not_active Application Discontinuation
  • 1994-11-04 JP JP7515606A patent/JPH09506016A/ja active Pending
  • 1994-11-04 KR KR1019960702876A patent/KR960706319A/ko not_active Application Discontinuation
  • 1994-11-04 CA CA002176480A patent/CA2176480A1/en not_active Abandoned

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