EP0912787A1 - Film respirant oriente de faible epaisseur et renforce par des adhesifs - Google Patents

Film respirant oriente de faible epaisseur et renforce par des adhesifs

Info

Publication number
EP0912787A1
EP0912787A1 EP97933519A EP97933519A EP0912787A1 EP 0912787 A1 EP0912787 A1 EP 0912787A1 EP 97933519 A EP97933519 A EP 97933519A EP 97933519 A EP97933519 A EP 97933519A EP 0912787 A1 EP0912787 A1 EP 0912787A1
Authority
EP
European Patent Office
Prior art keywords
film
adhesively
percent
adhesive
film layer
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP97933519A
Other languages
German (de)
English (en)
Inventor
Ann Louise Mccormack
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kimberly Clark Worldwide Inc
Kimberly Clark Corp
Original Assignee
Kimberly Clark Worldwide Inc
Kimberly Clark Corp
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 Kimberly Clark Worldwide Inc, Kimberly Clark Corp filed Critical Kimberly Clark Worldwide Inc
Publication of EP0912787A1 publication Critical patent/EP0912787A1/fr
Withdrawn legal-status Critical Current

Links

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 bandages or dressings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • 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
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
    • A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
    • A61F13/51401—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by the material
    • 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
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
    • A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
    • A61F13/51456—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties
    • A61F13/51458—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being air-pervious or breathable
    • A61F13/51462—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being air-pervious or breathable being defined by a value or parameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
    • 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
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/15203—Properties of the article, e.g. stiffness or absorbency
    • A61F2013/15284—Properties of the article, e.g. stiffness or absorbency characterized by quantifiable properties
    • 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
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/15203—Properties of the article, e.g. stiffness or absorbency
    • A61F2013/15284—Properties of the article, e.g. stiffness or absorbency characterized by quantifiable properties
    • A61F2013/15544—Permeability

Definitions

  • the present invention is directed to oriented, low gauge, breathable films.
  • Film materials have found widespread use in a wide variety of applications, including outer covers for personal care absorbent articles, such as diapers, training pants, incontinence garments, feminine hygiene products, sanitary napkins, wound dressing, bandages, and the like. Such film materials also have been found useful in consumer and industrial packaging.
  • Such thin films can have an effective gauge or thickness of 0.6 mil or less and a basis weight of 25.0 grams per square meter (gsm) or less.
  • the drawing or stretching orients the molecular structure of the polymer molecules within the film in the direction of stretching, thereby increasing the strength of the film in the machine direction.
  • the same machine direction oriented film is weakened in the cross direction in terms of tensile strength and trap tear properties.
  • a support layer or multiple support layers, such as a fibrous nonwoven web, has been laminated to the film layer to form a laminate having, among other properties, increased strength and durability.
  • Laminates of low-gauge or stretch-thinned films and nonwovens have been formed using thermal lamination techniques, in which heat and pressure, as with heated pattern rolls and ultrasonics, have been employed. Such thermal lamination may require a level of heat and pressure that results in undesired perforations in or localized film damage to the film layer, and/or in the resultant laminate being undesirably stiff.
  • thermally laminated film-nonwoven laminates have in some instances, particularly when employed as an outer cover for personal care absorbent articles, exhibited insufficient strength and durability properties, resulting in catastrophic tear failures of the film layer of the laminate during use of such absorbent articles.
  • thermally laminated film-nonwoven laminates tear failures of thermally laminated film-nonwoven laminates tend to propagate from thermal bond points or areas in which the film and nonwoven layers are bonded together. Accordingly, the need exists for an improved uniaxially (i.e., machine direction) oriented, low gauge film having enhanced strength and durability properties, particularly in the cross machine direction.
  • the adhesively-reinforced, uniaxially oriented, low gauge film material of independent claim 1 which comprises: a film layer having a surface; said film layer being oriented in a direction of stretching and having an effective gauge of 0.6 mil or less; said film layer being formed from a blend including, on a total weight percent basis based upon the total weight of the film layer, from about 30 percent to about 70 percent of a first polyolefin polymer, from about 70 percent to about 30 percent of a filler, and from about 0 to about 20 percent of a second polyolefin polymer; said film layer having a water vapor transmission rate of at least about 300 grams per square meter per 24 hours; a pattern of adhesive areas applied to said surface of said film layer; said pattern of adhesive areas having an add-on amount of from about 0.1 to about 20 grams per square meter (gsm), a percent bond area of from about 5 percent to about 50 percent per unit area of said surface of said film layer, and a maximum spacing between adhesive areas
  • Figure 1 is an elevational view of a random pattern of meltblown adhesive fibers applied to a surface of a film layer according to the present invention, in which the direction of stretching of the film layer is indicated by line x-x.
  • Figure 2 is an elevational view of a ribbed pattern of printed pigmented adhesive areas applied to a surface of a film layer according to the present invention, in which the direction of stretching of the film layer is indicated by line x-x.
  • Figure 3 is an elevational view of a cloud pattern of printed pigmented adhesive areas applied to a surface of a film layer according to the present invention, in which the direction of stretching of the film layer is indicated by line x-x.
  • the present invention is directed to an improved, adhesively-reinforced, uniaxially oriented, low gauge film material which utilizes a pattern or network of adhesive areas applied to a surface of the film layer to improve durability and strength of the uniaxially, typically machine direction, oriented film.
  • the adhesively- reinforced film material comprises a uniaxially oriented, low gauge film layer 12 having a surface 14 onto which is applied a pattern or network of adhesive fibers, filaments, lines or areas 18.
  • Adhesive areas 18 have a percent bond area of from about 5 percent to about 50 percent per unit area of the surface 14 of the film 12, and have a maximum spacing between adhesive areas 18 in a direction generally parallel to the direction of stretching (orientation) of no more than about 1.0 inch (about 25.4 millimeters (mm)).
  • the adhesive 18 is applied to a surface 14 of the film layer 12 at an add-on amount ranging from about 0.1 to about 20 grams per square meter (gsm).
  • the term "layer” when used in the singular can have the dual meaning of a single element or a plurality of elements.
  • machine direction or MD means the length of a material in the direction in which it is produced.
  • cross machine direction or CD means the width of a material, i.e., a direction generally perpendicular to the MD.
  • Film layer 12 includes at least two basic components: a polyolefin polymer, advantageously a predominately linear polyolefin polymer, such as linear low density polyethylene (LLDPE) or polypropylene, and a filler. These components are mixed together, heated and then extruded into a film layer using any one of a variety of film- producing processes known to those of ordinary skill in the film processing art. Such filmmaking processes include, for example, cast embossed, chill and flat cast, and blown film processes. Other additives and ingredients may be added to the film layer 12 provided they do not significantly interfere with the ability of the film layer to function in accordance with the teachings of the present invention.
  • a polyolefin polymer advantageously a predominately linear polyolefin polymer, such as linear low density polyethylene (LLDPE) or polypropylene
  • LLDPE linear low density polyethylene
  • filler a filler.
  • the film layer 12 will include from about 30 to about 70 weight percent of the polyolefin polymer, and from about 30 to about 70 weight percent of the filler. In more specific embodiments, it may include in addition from about 0 to about 20 percent by weight of another polyolefin polymer, such as low density polyethylene.
  • Linear low density polyethylene has been found to work well as a film base when blended with appropriate amounts of a filler. It is believed, however, that any suitable polyolefin polymer can be used in forming the film layer 12 of the present invention, and advantageously any predominately linear polyolefin polymer can be used in forming the film layer 12 of the present invention.
  • the term "linear low density polyethylene” is meant to include polymers of ethylene and higher alpha olefin comonomers such as C 3 - C 12 and combinations thereof and has a Melt Index (Ml) as measured by ASTM D-1238 Method D of from about 0.5 to about 10 (grams per 10 minutes at 190 degrees Celsius (°C)).
  • predominately linear it is meant that the main polymer chain is linear with less than approximately 5 long chain branches per 1000 ethylene units. Long chain branches would include carbon chains greater than C 12 .
  • short chain branching C 3 - C 12
  • C 3 - C 12 short chain branching due to comonomer inclusion will typically be limited to less than 20 short chains per 1000 ethylene units and 20 or greater for polymers which are elastomeric.
  • predominately linear polyolefin polymers include, without limitation, polymers produced from the following monomers: ethylene, propylene, 1-butene, 4-methyl-pentene, 1- hexene, 1-octene and higher olefins as well as copolymers and terpolymers of the foregoing.
  • copolymers of ethylene and other olefins including butene, 4- methyl-pentene, hexene, heptene, octene, decene, etc., would also be examples of predominately linear polyolefin polymers.
  • the film layer 12 also includes a filler.
  • a "filler” is meant to include particulates and other forms of materials which can be added to the film polymer extrusion blend and which will not chemically interfere with the extruded film but which are able to be uniformly dispersed throughout the film.
  • the fillers will be in particulate form and may have a spherical or non-spherical shape with average particle sizes in the range of about 0.1 to about 7 microns. Both organic and inorganic fillers are contemplated to be within the scope of the present invention provided that they do not interfere with the film formation process, or the ability of the film layer to function in accordance with the teachings of the present invention.
  • suitable fillers include calcium carbonate (CaCO 3 ), various kinds of clay, silica (SiO 2 ), alumina, barium carbonate, sodium carbonate, magnesium carbonate, talc, barium sulfate, magnesium sulfate, aluminum sulfate, titanium dioxide (TiO 2 ), zeolites, cellulose-type powders, kaolin, mica, carbon, calcium oxide, magnesium oxide, aluminum hydroxide, pulp powder, wood powder, cellulose derivatives, chitin and chitin derivatives.
  • a suitable coating such as, for example, stearic acid, may also be applied to the filler particles, as desired.
  • film layer 12 may be formed using any one of the conventional processes known to those familiar with film formation.
  • the polyolefin polymer and filler are mixed in appropriate proportions given the ranges outlined herein and then heated and extruded into a film.
  • the filler should be uniformly dispersed throughout the polymer blend and, consequently, throughout the film layer itself.
  • a film is considered "breathable" if it has a water vapor transmission rate of at least 300 grams per square meter per 24 hours (g/m 2 /24 hrs) as calculated using the test method described herein.
  • the film once the film is formed, it will have a weight per unit area of less than about 80 grams per square meter (gsm) and after stretching and thinning, its weight per unit area will be from about 12 grams per square meter to about 25 grams per square meter
  • the film layers used in the examples of the present invention described below were monolayer films, however, other types, such as multi-layer films, are also considered to be within the scope of the present invention provided the forming technique is compatible with filled films.
  • the film as initially formed is generally thicker and noisier than desired, as it tends to make a "rattling" sound when shaken. Moreover, the film does not have a sufficient degree of breathability as measured by its water vapor transmission rate. Consequently, the film is heated to a temperature equal to or less than about 5 °C below the melting point of the polyolefin polymer and then stretched using an in-line machine direction orientation (MDO) unit to at least about two times (2X) its original length to thin the film and render it porous. Further stretching of the film layer 12, to about three times (3X), four times (4X), or more, its original length is expressly contemplated in connection with forming film layer 12 of the present invention.
  • MDO machine direction orientation
  • Film layer 12 after being stretch-thinned should have an "effective" film gauge or thickness of from about 0.2 mil to about 0.6 mil.
  • the effective gauge is used to take into consideration the voids or air spaces in breathable film layers. For normal, non-filled, non- breathable films, the actual gauge and effective gauge of the film will typically be the same. However, for filled films that have been stretch-thinned, as described herein, the thickness of the film will also include air spaces. In order to disregard this added volume, the effective thickness is calculated according to the test method set forth herein.
  • An additional feature of the stretch-thinning process is the change in opacity of the film material.
  • the film is relatively transparent, however, after stretching the film becomes opaque.
  • the film becomes oriented during the stretch- thinning process, it also becomes softer and the degree of "rattling" is reduced.
  • Such uniaxially, machine direction oriented films typically do not have good strength properties in the cross machine direction, resulting in films that are easily torn or split along the machine direction (the direction of stretching).
  • the inventors have discovered that by applying a network or pattern of adhesive areas as defined herein to a surface of such a film, strength and durability of the film material can be enhanced.
  • adhesive as used herein is intended to refer to any suitable hot melt, water or solvent borne adhesive that can be applied in the required pattern or network of adhesive areas to form the adhesively-reinforced, uniaxially oriented, low gauge film of the present invention.
  • suitable adhesives include conventional hot melt adhesives, pressure-sensitive adhesives and reactive adhesives (i.e., polyurethane).
  • block copolymer-type construction adhesives ethylene vinyl acetate (EVA)- based adhesives (e.g., 18 - 30 weight percent vinyl acetate) and amorphous alphaolefin copolymer and terpolymer-based adhesives have been found to work well in forming the adhesively-reinforced, uniaxially oriented, low gauge film of the present invention. All such adhesive types can be formulated to contain waxes and tackifiers to improve processing or hot tack or softness.
  • EVA ethylene vinyl acetate
  • amorphous alphaolefin copolymer and terpolymer-based adhesives have been found to work well in forming the adhesively-reinforced, uniaxially oriented, low gauge film of the present invention.
  • All such adhesive types can be formulated to contain waxes and tackifiers to improve processing or hot tack or softness.
  • the adhesive application process employed must be suited to the particular type of adhesive used, and to the particular end use application for which the adhesively- reinforced, uniaxially oriented, low gauge film is intended.
  • the adhesive can be applied, for example, in a pattern or network of intersecting, randomly dispersed meltblown adhesive fibers. Such meltblown adhesive fibers typically have average diameters in the range of from about 5 microns to about 50 microns.
  • meltblown adhesive fibers is intended to include both discontinuous and continuous adhesive fibers. Processes for applying meltblown fibers onto the surface of a moving substrate are known, as exemplified by U.S. Pat. No. 4,720,252 to Appel et al., the disclosure of which is incorporated herein by reference.
  • suitable processes for applying adhesive to the film layer 12 include, for example, sprayed or swirled hot melt adhesive areas, and screen or gravure printing of adhesive areas.
  • melt spraying and adhesive printing processes are well known in the art and are, therefore, not described in detail herein.
  • Application of adhesives, particularly pigmented adhesives, using such printing processes offers additional aesthetic benefits, as the adhesive pattern can be in the form of geometric or non-geometric and repeating or non-repeating shapes, continuous or discontinuous lines, fanciful or arbitrary designs, symbols or objects, or even text or words.
  • the adhesive patterns shown in Figures 2 and 3 are illustrative of such printed adhesive patterns.
  • Certain printing processes such as screen printing, require direct contact between the screen and the substrate being printed.
  • Printing certain types of adhesives can prove problematic due to the high tack or level of adhesion of such adhesives at ambient temperature.
  • Screen printing of such adhesives can be accomplished, however, by printing the adhesive onto a suitable release surface, such as, for example, a release paper, and then transferring the printed adhesive onto the film layer 12 from the release surface.
  • the adhesive application process employed to apply adhesive 18 to surface 14 of film layer 12 must be capable of effectively controlling the amount of adhesive available for film layer reinforcement, and the adhesive application pattern. Moreover, application of adhesive 18 should be substantially coextensive with the length and width of film layer 12, in order to ensure uniformity in strength and durability properties of the adhesively- reinforced film.
  • a primary function of the adhesive areas is to reinforce the low gauge or stretch- thinned film layer of the present invention.
  • films that are highly oriented (2X or more) in the machine direction (MD) tend to be "splitty" in the machine direction when subjected to cross machine direction (CD) tensile forces.
  • CD cross machine direction
  • the inventors have observed that a randomly dispersed, intersecting network of meltblown adhesive areas applied to such a film in accordance with the present invention works particularly well in providing a "rip-stop" against such film splitting by distributing CD tensile loads applied to the film, thereby enhancing the durability and strength of such machine direction oriented films.
  • the network of randomly dispersed, intersecting meltblown adhesive areas includes individual meltblown adhesive fibers that are "closely spaced” in the MD.
  • closely spaced adhesive areas refers to adhesive areas that are separated by a maximum distance between individual adhesive areas of about 1.0 inch (25.4 mm) in a direction generally parallel to the direction of stretching, and more specifically a maximum distance of 0.25 inch (6.35 mm), and even more specifically a maximum distance of 0.125 inch (3.18 mm).
  • the term "generally parallel to the direction of stretching” means a line along which the distance between adhesive areas is measured will have an interior angle with a line in the direction of stretching of less than or equal to 30°.
  • a randomly dispersed, intersecting network of adhesive areas such as meltblown adhesive fibers
  • meltblown adhesive fibers can be effectively utilized in forming the adhesively-reinforced, uniaxially oriented, low gauge film of the present invention
  • other adhesive application patterns and methods can be employed as well.
  • generally parallel, continuous and/or discontinuous, adhesive lines extending or oriented in the cross machine direction and printed onto surface 14 of film layer 12 at an add-on amount and percent bond area within the ranges specified herein can impart the desired increase in strength and durability to film layer 12.
  • Use of suitable adhesive application methods is limited by their capacity to control the add-on amount of adhesive used, percent bond area of the adhesive areas, and the maximum spacing between individual adhesive areas in the direction of stretching (MD).
  • the adhesive add-on amount should range from about 0.1 to about 20 grams per square meter, and more specifically from about 0.25 to about 5.0 grams per square meter , and even more specifically from about 0.5 to about 1.5 grams per square meter. Reducing the add-on amount lowers the cost of producing the adhesively-reinforced, uniaxially oriented, low gauge film, and reduces the risk of compromising breathability of the film layer. By way of contrast, higher add-on amounts of adhesive provide more durable film materials.
  • the microporosity or breathability of the film material is not significantly reduced
  • the portion of the total area of surface 14 of the film layer 12 to which adhesive areas 18 are applied can be expressed as a percent bond area.
  • percent bond area refers to the portion of the total plan area of surface 14 of the film layer 12 that is occupied by adhesive areas 18
  • the percent bond area can be measured by a variety of conventional techniques, including imaging analysis as described herein
  • the type of adhesive utilized can be appropriately selected to impart additional functionality to the adhesively- reinforced, uniaxially oriented, low gauge film of the present invention
  • the adhesive can be selected so that it has sufficient open time, that is, remains tacky for a sufficient time to allow the adhesive 18 also to bond surface 14 of the film layer 12 to a surface of an adjacent layer, such as a nonwoven web or fabric
  • the terms "nonwoven web” or “nonwoven fabric” mean a web having a structure of individual fibers or filaments that are interlaid, but not in an identifiable, repeating manner as in a knitted or woven fabric
  • Nonwoven webs can be formed by a variety of known forming processes, including spunbonding, airiaying, meltblowing, or bonded carded web formation processes
  • suitable adjacent layers to which surface 14 of film layer 12 could be adhesively bonded include woven and/or knitted fabrics, and foam
  • adhesively-reinforced film matenal of the present invention has been described herein as uniaxially stretched or oriented, the benefits and advantages of the present invention can apply to biaxially stretched or oriented films as well.
  • adhesive areas 18 to a surface 14 of the film layer 12 has been described herein, adhesive areas also can be applied to a surface opposing surface 14 of the film layer 12, wherein adhesive areas on the opposing surfaces of film layer 12 are identical or different in terms of add-on amount, percent bond area and maximum spacing in the direction of stretching.
  • the effective gauge of a film material was calculated by dividing the basis weight of the film by the density of the polymer(s) and fillers forming the film. To obtain the effective gauge of a film material in units of inches, the weight per unit area measured in ounces per square yard (osy) was multiplied by 0.001334 (a metric to English conversion factor) and the result was divided by the density of the polymer formulation in grams per cubic centimeter (g/cc).
  • the strip test method for tensile strength and elongation measures the breaking load and percent elongation before rupture of a material. These measurements are made while the material is subjected to a continually increasing load in a single direction at a constant rate of extension.
  • each sample film material 3 specimens were cut with a 3 inch (76 mm) wide precision cutter, with each having a width of 3 inches (76 mm) and length of 6 inches (152 mm), with the long dimension parallel to the direction of testing and force application.
  • the entire width of each specimen was placed within clamps of a constant-rate-of-extension tester, such as a Sintech System 2 Computer Integrated Testing System manufactured by MTS Systems Corporation of Eden Prairie, Minnesota.
  • the length or long dimension of each specimen was set as nearly parallel as possible to the direction of force application.
  • a continuous load was applied to the specimen, with the crosshead speed set at 300 millimeters per minute, until the specimen ruptured.
  • the peak load and peak strain required just prior to rupture of each specimen was measured and average values are recorded herein.
  • the water vapor transmission rate (WVTR) for the sample materials was calculated in accordance with ASTM Standard E96-80. Circular samples measuring three inches in diameter were cut from each of the test materials and a control, which was a piece of CELGARD® 2500 film from Hoechst Celanese Corporation of Sommerville, New Jersey. CELGARD® 2500 film is a microporous polypropylene film. Three samples were prepared for each material. The test dish was a number 60-1 Vapometer pan distributed by Thwing-Albert Instrument Company of Philadelphia, Pennsylvania. One hundred milliliters (ml) of distilled water was poured into each Vapometer pan and individual samples of the test materials and control material were placed across the open tops of the individual pans.
  • WVTR water vapor transmission rate
  • Screw-on flanges were tightened to form a seal along the edges of each pan (no sealant grease is used), leaving the associated test material or control material exposed to the ambient atmosphere over a 6.5 centimeter (cm) diameter circle having an exposed area of approximately 33.17 square centimeters.
  • the pans were weighed, then were placed in a forced air oven set at a temperature of 37 °C. The oven was a constant temperature oven with external air circulating through it to prevent water vapor accumulation inside.
  • a suitable forced air oven is, for example, a Blue M Power-O-Matic 60 oven distributed by Blue M Electric Company of Blue Island, Illinois. After 24 hours, the pans were removed from the oven and weighed again.
  • the preliminary test water vapor transmission rate values were calculated as follows:
  • Test WVTR (grams weight loss over 24 hours) x 315.5 g/m 2 /24 hrs
  • the relative humidity within the oven was not specifically controlled.
  • the WVTR for the CELGARD® 2500 film control has been determined to be 5000 grams per square meter for 24 hours. Accordingly, the control sample was run with each test and the preliminary test values were corrected to set condition using the following equation:
  • WVTR (Test WVTR/control WVTR) x 5000 g/m 2 /24 hrs) g/m 2 /24 hrs
  • the adhesive bond area test measures the portion of a unit area of a surface of the film layer to which a pattern of adhesive areas is applied.
  • the maximum spacing test measures the maximum free path measurement between adhesive areas in the direction of stretching of the film.
  • the stained laminates were peeled open by hand, leaving the stained adhesive on a surface of the film layer of each laminate.
  • the osmium tetroxide de-tackifies and crosslinks (strengthens) the adhesive, facilitating delamination of the film and nonwoven layers.
  • the stained adhesive was imaged in reflected light using a Wild M420 macro instrument available from Leica of Deerfield, Illinois, with a FOSTEC fiber optic ringlight. Images were acquired through an Model CCD-72 monochrome camera system available from Dage MTI of Michigan City, Indiana, directly into a Princeton Gamma Tech (of Princeton, New Jersey) ImagistTM system. The video camera manual controls were used, so that there was no variation in image density due to automatic gain control compensation. The images were thresholded, binarized and analyzed using Princeton Gamma Tech image analysis software. The resulting images were printed out on a Hewlett Packard PaintJetTM printer. The average values for percent bond area and the maximum spacing between adhesive areas in the direction of stretching for Example film materials 1 - 3 are reported herein.
  • sample adhesively-reinforced, uniaxially oriented, low gauge films A total of 4 sample adhesively-reinforced, uniaxially oriented, low gauge films are set forth below.
  • the sample adhesively-reinforced, uniaxially oriented, low gauge films are designed to illustrate particular embodiments of the present invention and to teach one of ordinary skill in the art the manner of carrying out the present invention.
  • the film layer contained, on a total weight percent basis based upon the weight of the film, 50% Dowlex® NG3347A linear low density polyethylene having a melt index of 2.3 (grams per 10 minutes at 190 °C) and a density of 0.917 grams per cubic centimeter (g/cc) and 5% Dow® 640 branch low density polyethylene having a melt index of 2.0 (grams per 10 minutes at 190 °C) and a density of 0.922 g/cc.
  • the blend of polyethylene polymers had a melt index of 1.85 (grams per 10 minutes at 190 °C) and a density of 1.452 g/cc.
  • the Dowlex® and Dow® polymers are available from Dow Chemical U.S.A., of Midland, Michigan.
  • the film layer further contained 45% by total weight English China SupercoatTM calcium carbonate (CaCO 3 ) coated with 1% stearic acid, having a 1 micron average particle size and a top cut of 7 microns.
  • the calcium carbonate was obtained from ECCA Calcium Products, Inc. in Sylacauga, Alabama, a division of ECC International.
  • the film formulation was blown into a mono-layer film at a melt temperature of 333 °F (168 °C) to produce a film having an initial unstretched gauge of about 1.5 mils (about 54 gsm).
  • the film was heated to a temperature of about 160 °F (71 °C) and the film was stretch-thinned to about 4.0 times its original length to an effective gauge of about 0.46 mil (about 18 gsm) using a machine direction orientation (MDO) unit, Model No. 7200 available from Marshall & Williams of Buffalo, Rhode Island, operating at a line speed of 500 feet per minute (152 meters per minute).
  • MDO machine direction orientation
  • the film was annealed at a temperature of 215 °F (103 °C).
  • the film was breathable as indicated by the WVTR data set forth in Table I below. A pattern or network of adhesive areas was applied to a surface of the film, in accordance with the teachings herein.
  • the adhesive was a butene copolymer of atactic polypropylene adhesive available from Rexene Corp. of Dallas, Texas, under the product designation Rextac RT2730.
  • the adhesive was applied to the film layer in the form of randomly dispersed meltblown adhesive fibers, using conventional meltblown apparatus essentially as described in U.S. Pat. No. 4,720,252, the disclosure of which is incorporated herein by reference.
  • the adhesive was heated to about 350 °F (177 °C) and applied to the film at an air temperature of about 430 °F (221 °C), an air pressure of about 20 psig (1.41 kilograms per square centimeter), a forming height of about 3.0 inches (76.2 mm) and a line speed of about 300 feet per minute (91 meters per minute).
  • the adhesive add-on amount was about 1.5 gsm and the maximum spacing of the adhesive areas in the direction of stretching of the film layer was about 0.5 inch (12.7 mm).
  • the average percent bond area was about 18 percent.
  • the film layer was the same as described in Example 1 , with no adhesive areas applied.
  • the film layer contained, on a total weight percent basis based upon the weight of the film, 45% Dowlex® NG3347A linear low density polyethylene and 55% by total weight English China SupercoatTM calcium carbonate (CaCO 3 ), both as described in detail in Example 1 above.
  • the film formulation was cast into a mono-layer film at a melt temperature of 360 °F (182 °C) to produce a film having an initial unstretched gauge of about 1.5 mils (about 54 gsm).
  • the film was heated to a temperature of about 160 °F (71 °C) and the film was stretch-thinned to about 4.7 times its original length to an effective gauge of about 0.46 mil (about 18 gsm) using an MDO unit as described in Example 1 above operating at a line speed of 500 feet per minute (152 meters per minute).
  • the film was annealed at a temperature of 200 °F (93 °C).
  • the film was breathable as indicated by the WVTR data set forth in Table I below.
  • a pattern or network of adhesive areas was applied to a surface of the film, in accordance with the teachings herein.
  • the adhesive was a pigmented block-copolymer pressure sensitive adhesive available from National Starch and Chemical Corp., having offices in Bridgewater, New Jersey, under the product designation Dispomelt® NS34-5610.
  • the adhesive was applied to the film layer by first printing the adhesive in a cloud pattern as shown in FIG. 3 hereof to a suitable release paper and then transferring the adhesive to the film layer surface, using a conventional screen printing and transfer process.
  • the adhesive was applied to the release paper at a line speed of about 25-50 feet per minute (7.6-15.2 meters per minute) and the adhesive was transferred to the film layer at a line speed of 300 feet per minute (91 meters per minute).
  • the adhesive add-on amount was about 9.0 gsm and the maximum spacing of the adhesive areas in the direction of stretching of the film layer was about 1.0 inch (25.4 mm).
  • the average percent bond area was about 12 percent.
  • the film layer was the same as described in Example 2, with no adhesive areas applied.
  • An adhesively-reinforced, uniaxially oriented, low gauge film according to the present invention was made.
  • the film layer and adhesive used was the same as described in Example 2 above.
  • the adhesive was applied to the film layer by first printing the adhesive in a ribbed pattern as shown in FIG. 2 hereof to a suitable release paper and then transferring the adhesive to the film layer surface, as described in Example 2.
  • the adhesive was applied to the release paper at a line speed of about 25-50 feet per minute (7.6 - 15.2 meters per minute) and the adhesive was transferred to the film layer at a line speed of 300 feet per minute (91 meters per minute).
  • the adhesive add-on amount was about 17.0 gsm and the maximum spacing of the adhesive areas in the direction of stretching of the film layer was about 0.25 inch (6.35 mm).
  • the average percent bond area was about 22 percent.
  • An adhesively-reinforced, uniaxially oriented, low gauge film according to the present invention was made.
  • the film and the adhesive used were the same as described above in Example 2, except the adhesive was non-pigmented.
  • the adhesive was applied to the film layer using a Control CoatTM spray adhesive pattern applicator available from Nordson Corp., having offices in Norcross, Georgia, under the product designation Metered Control CoatTM Applicator.
  • the adhesive was heated to about 350 °F (177 °C) and applied to the film at an air temperature of about 380 °F (193 °C), an air pressure of about 80 psig (5.63 kg/cm 2 ), a forming height of about 1.0 inch (25.4 mm) and a line speed of about 400 feet per minute (120 meters per minute).
  • the adhesive add-on amount was about 2.0 gsm and the maximum spacing of the adhesive areas in the direction of stretching of the film layer was about 0.1 inch (2.54 mm).
  • the average percent bond area was about 15 percent. Comparative Example
  • a non-breathable film layer was obtained from the film-nonwoven laminate outer cover of a disposable diaper sold commercially by Kimberly-Clark Corporation, the assignee of the present invention, under the product designation Huggies® Ultratrim diapers. No adhesive was applied to this film layer.
  • the film layer had an effective gauge of about 0.41 mil.
  • Example 1 6300 162 870 550
  • the adhesively-reinforced, uniaxially oriented, low gauge film constructed in accordance with the present invention will be tailored and adjusted by those of ordinary skill in the art to accommodate various levels of performance demand imparted during actual use. Accordingly, while this invention has been described by reference to certain specific embodiments and examples, it will be understood that this invention is capable of further modifications. This application is, therefore, intended to cover any variations, uses or adaptations of the invention following the general principles thereof, and including such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and fall within the limits of the appended claims.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dermatology (AREA)
  • Epidemiology (AREA)
  • Textile Engineering (AREA)
  • Laminated Bodies (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

ta présente invention concerne un film respirant renforcé par des adhésifs, à orientation uniaxiale et de faible épaisseur (aminci par étirement) sur lequel on applique un motif ou un réseau de zones adhésives afin d'en augmenter la durabilité et la résistance. La présente invention est applicable dans des domaines très variés dans lesquels sont exigées ou souhaitées des qualités telles que la résistance, le confort, l'imperméabilité aux liquides et la respirabilité, y compris et de manière non limitative, les articles absorbants d'hygiène personnelle.
EP97933519A 1996-07-15 1997-07-09 Film respirant oriente de faible epaisseur et renforce par des adhesifs Withdrawn EP0912787A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US2173296P 1996-07-15 1996-07-15
US21732P 1996-07-15
US88209197A 1997-06-25 1997-06-25
US882091 1997-06-25
PCT/US1997/012452 WO1998002609A1 (fr) 1996-07-15 1997-07-09 Film respirant oriente de faible epaisseur et renforce par des adhesifs

Publications (1)

Publication Number Publication Date
EP0912787A1 true EP0912787A1 (fr) 1999-05-06

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EP97933519A Withdrawn EP0912787A1 (fr) 1996-07-15 1997-07-09 Film respirant oriente de faible epaisseur et renforce par des adhesifs

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EP (1) EP0912787A1 (fr)
JP (1) JP2002515926A (fr)
KR (1) KR20000023817A (fr)
CN (1) CN1230234A (fr)
AU (1) AU3668697A (fr)
BR (1) BR9710480A (fr)
CA (1) CA2260793A1 (fr)
PE (1) PE96098A1 (fr)
PL (1) PL331172A1 (fr)
WO (1) WO1998002609A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6309736B1 (en) * 1994-12-20 2001-10-30 Kimberly-Clark Worldwide, Inc. Low gauge films and film/nonwoven laminates
US6080818A (en) * 1997-03-24 2000-06-27 Huntsman Polymers Corporation Polyolefin blends used for non-woven applications
AU9200898A (en) * 1997-08-21 1999-03-08 Tredegar Corporation Perforated contoured film for use in a bandage
FR2821741A1 (fr) * 2001-03-08 2002-09-13 Catherine Simone Marthe Piquet Couche culotte adulte amelioree
US20040241399A1 (en) * 2003-03-21 2004-12-02 Marmon Samuel E. Pattern bonded nonwoven fabrics
AU2005336447B2 (en) 2005-09-13 2011-12-08 Sca Hygiene Products Ab Absorbent articles and laminates containing a bonding pattern
EP2740451A1 (fr) * 2012-12-10 2014-06-11 Kao Corporation Article absorbant
CN106948091B (zh) * 2017-04-19 2023-06-20 广东必得福医卫科技股份有限公司 一种单向拉伸弹性无纺布生产设备
JP7447018B2 (ja) * 2018-05-03 2024-03-11 エイブリィ・デニソン・コーポレイション 接着積層体及び接着積層体の製造方法

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Publication number Priority date Publication date Assignee Title
EP0505027B1 (fr) * 1991-03-22 1996-11-06 Kappler Safety Group Etoffe composite perméable
CA2097630A1 (fr) * 1992-12-29 1994-06-30 Ann Louise Mccormack Matiere lamellee, etiree et coussinee en vrac
CA2116081C (fr) * 1993-12-17 2005-07-26 Ann Louise Mccormack Materiau permeable a l'air constitue d'une pellicule et d'un non-tisse colles
CA2123330C (fr) * 1993-12-23 2004-08-31 Ruth Lisa Levy Non-tisse cotele ressemblant a une etoffe et procede pour sa fabrication
CA2148392A1 (fr) * 1994-06-06 1995-12-07 Ann Louise Mccormack Pellicule amincie par etirage, et stratifie non tisse
ZA9510307B (en) * 1994-12-20 1996-06-11 Kimberly Clark Co Mechanically compatibilized film/non-woven laminates

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9802609A1 *

Also Published As

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WO1998002609A1 (fr) 1998-01-22
KR20000023817A (ko) 2000-04-25
CA2260793A1 (fr) 1998-01-22
BR9710480A (pt) 2002-03-12
CN1230234A (zh) 1999-09-29
PL331172A1 (en) 1999-06-21
PE96098A1 (es) 1999-01-11
AU3668697A (en) 1998-02-09
JP2002515926A (ja) 2002-05-28

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