WOUND ROLL CORE COVERING

TECHNICAL FIELD

The present disclosure relates generally to a covering for a winding core and particularly to a winding core covering for use with an impressionable web material.

BACKGROUND

Polymeric films such as, for example, optical films, are commonly wound onto cores to form rolls of web material for use during manufacturing, handling, and transporting. In a cut transfer process, the starting end of the web is adhered to a core material using a strip of adhesive tape or other means to secure the starting end of the film to the core. Because of this attachment scheme, as the leading edge of the web is covered by the subsequent layers of wound web an effective irregularity on the core surface can increase the stress in adjacent web layers over that portion of the core surface. This irregularity can propagate impressions to several adjacent layers of the web, causing defects that are often referred to as “core impressions.” These core impressions may be observed on many of the initial layers of wound web material on each roll and can result in product unsuitable for further processing and use, i.e., wasted product.

FIG. 1A shows a cross-sectional schematic of an illustrative embodiment of prior art film roll core 100. FIG. 1A, prior art film roll core 100 includes cylindrical tube 110 having inside surface 112, outside surface 114, and center of rotation 115. Inside surface 112 is typically mounted on the mandrel of a film winding apparatus (not shown). Starting end (also sometimes referred to as leading end) 122 of web 120 is disposed on outside surface 114 of cylindrical tube 110, and web 120 is wound around cylindrical tube 110. A region of increased stress 130 within film 120 is generated by the tension “T” applied to web 120 as first wrap overlap 124 of web 120 overlays starting end 122. The region of increased stress 130 can result in a visible deformation in the web. First wrap overlap 124 generally follows the contour of the surface over which it is wrapped, and starting end 122 generates a step-change in outside surface 114 of the cylindrical tube, corresponding to the thickness “t” of the polymeric film. Subsequent second wrap overlap 126 overlays first wrap overlap 124 and starting end 122, again resulting in a visible deformation in web 120 in the region of increased stress 130. Depending upon the impressionability of the film, subsequent wrap overlaps may exhibit similar, though typically progressively decreasing, amounts of undesired core impression damage.

FIG. 1B shows a cross-sectional view of another embodiment of prior art film roll core 101. In FIG. 1B, prior art film roll core 101 includes cylindrical tube 110 having inside surface 112, outside surface 114, and center of rotation 115. Inside surface 112 is typically mounted on the mandrel of a film winding apparatus (not shown). Starting end 122 of web 120 is disposed on outside surface 114 of cylindrical tube 110, and web 120 is wound around cylindrical tube 110. Starting end 122 of web 120 can be attached to cylindrical tube 110 using adhesive tape 123 on outside surface 114 of the cylindrical tube 110. Alternatively (not shown), adhesive may be used under leading edge 122 to secure web 120 to outside surface 114. A region of increased stress 130 is generated by the tension “T” applied to web 120 as first wrap overlap 124 of web 120 overlays starting end 122 and adhesive tape 123. The region of increased stress 130 can result in a visible deformation in the web. First wrap overlap 124 generally follows the contour of the surface over which it is wrapped, and starting end 122 generates a step-change in outside surface 114 of the cylindrical tube, corresponding to the thickness “t” of the polymeric film, as well as a second step-change in the outer surface corresponding to the thickness of adhesive tape 123. Subsequent second wrap overlap 126 overlays first wrap overlap 124, starting end 122, and adhesive tape 123, again resulting in a visible deformation in web 120 in the region of increased stress 130.

FIG. 1C shows a cross-sectional schematic of another illustrative embodiment of a prior art film roll core 102, such as is disclosed in U.S. Pat. No. 9,290,348 (Newhouse et al.). Open gap film roll core 102 includes cylindrical tube 110 having inside surface 112, outside surface 114 and center of rotation 115. Inside surface 112 is typically mounted on the mandrel of a film winding apparatus (not shown). Compliant layer 140 is disposed on outside surface 114 of cylindrical tube 110, such that gap 150 remains between first edge 146 and second edge 148 of compliant layer 140. Compliant layer 140 can be attached to outside surface 114 by an adhesive layer (not shown) between outside surface 114 of cylindrical tube 110 and inner compliant surface 142 of compliant layer 140. A second adhesive layer (not shown) can be disposed on outside compliant surface 144 of compliant layer 140 (e.g., from a portion proximate to first edge 146 up to and including the entire outside compliant surface 144). In accordance with that invention, gap 150 is used to accommodate the starting end of the web 122 to be wound on the cylindrical tube 110 such that subsequently wound layers of the web suffer reduced impressions in areas corresponding to the region of increased stress 130.

SUMMARY

In one aspect provided herein are winding core coverings for use with an impressionable web material, the winding core coverings including a backing, the backing having an adhesive layer and a support layer in contact with the adhesive layer, and a web contact layer in contact with the backing, the web contact layer including a thermoplastic polymer, where the outer surface of the web contact layer has a structured surface comprising a plurality of protrusions having an average height (“H”) of 50 μm to 600 μm.

In another aspect provided herein are winding cores including the disclosed winding core coverings.

As used herein:

The term “web” refers to thin materials which are manufactured and/or processed in continuous, flexible strip form.

All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified.

As used in this specification and the appended claims, past tense verbs such as “coated” and “embossed” are intended to represent structure, and not to limit the process used to obtain the recited structure, unless otherwise specified.

As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise.

As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

As used herein, “have”, “having”, “include”, “including”, “comprise”, “comprising” or the like are used in their open-ended sense, and generally mean “including, but not limited to.” It will be understood that the terms “consisting of” and “consisting essentially of” are subsumed in the term “comprising,” and the like.

Features and advantages of the present disclosure will be further understood upon consideration of the detailed description as well as the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C show a cross-sectional schematic of a prior art film roll core in use.

FIG. 2 is a cross-sectional schematic of an embodiment of a wound roll core covering of the present disclosure.

FIG. 3A is a cross-sectional schematic of an embodiment of a wound roll core covering of the present disclosure.

FIG. 3B is a cross-sectional schematic of an embodiment of a wound roll core covering of the present disclosure.

FIG. 4 is a cross-sectional schematic of an illustrative covered winding core of the present disclosure.

FIG. 5 is a cross-section schematic of the covered winding core shown in FIG. 4 in use.

FIG. 6 shows a plan view of an exemplary tool pattern for creation of a textured surface useful in embodiments of the wound roll core covering of the present disclosure.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.

DETAILED DESCRIPTION

Disclosed herein are novel winding core covers that, among other advantages, allow for web leading edge capture around the entire winding core. Such winding core covers are characterized by a patterned surface having enough compliance to smooth out possible wrinkles at the leading edge to provide improved cut transfers at the winder and minimize core defects propagation through a wound roll (e.g., leading edge impressions), while also providing a backing layer that allows for secure and convenient application of the covering to the winding core. In one aspect a winding core covering 10 is provided, as shown in FIG. 2, the winding core covering 10 including a backing 45 and a web contact layer 20.

As shown in FIG. 2, the backing 45 includes an adhesive layer 40 having a first major surface 46 and a second major surface 47 and a support layer 30, the support layer 30 having a first major surface 36 and a second major surface 37, where the first major surface of the support layer 36 is in contact with the second major surface of the adhesive layer 47. In some embodiments, the support layer 36 may include a nonwoven material, such as, for example, a nonwoven scrim fabric including polyethylene terephthalate.

In some embodiments, the support layer 36 may include a polymer resin such as, for example, a polypropylene resin, a low-density polyethylene resin (e.g., a linear low-density polyethylene), a high-density polyethylene resin, a polyethylene terephthalate resin, a polycarbonate resin, and combinations thereof. In any embodiment of the backing disclosed herein, the adhesive layer 40 and the support layer 40 are selected to be compatible with each other such that the first major surface of the support layer 36 and the second major surface of the adhesive layer 47 bond, i.e., stick, together. In some preferred embodiments, the adhesive layer 40 comprises a double-sided adhesive tape, such as those commercially available under the trade designation 3M REMOVABLE REPOSITIONABLE DOUBLE COATED TAPE 9425HT from 3M Company, Saint Paul, Minnesota, USA. In some preferred embodiments, the support layer 36 comprises a low-density polyethylene.

In some embodiments, backing 45 has a thickness of at least 50 μm, at least 75 μm, or at least 100 μm. In some embodiments, backing 45 has a thickness of at most 380 μm, at most 350 μm, or at most 320 μm. In preferred embodiments, backing 45 has a thickness of 50 μm to 380 μm.

Web contact layer 20 has a first major surface 26 and a second major surface 27, where the second major surface of the support layer 37 is in contact with the first major surface of the web contact layer 26 at an interface 23 that is substantially planar, i.e. flat. In some embodiments and as shown in FIGS. 3A and 3B, interface 23 may not be planar. In any embodiment disclosed herein, the web contact layer 20 and the support layer 30 are selected to be compatible with each other such that the first major surface of the web contact layer 26 and the second major surface of the support layer 37 bond. In some preferred embodiments the support layer 30 is more dense than web contact layer 20. In some preferred embodiments the support layer 30 has a higher tensile strength than web contact layer 20.

The web contact layer 20 typically comprises a thermoplastic polymer. Suitable thermoplastic polymers include polyolefin homopolymers such as polyethylene and polypropylene, copolymers of ethylene, propylene and/or butylene; copolymers containing ethylene such as ethylene vinyl acetate and ethylene acrylic acid; ionomers based on sodium or zinc salts of ethylene methacrylic acid or ethylene acrylic acid; polyvinyl chloride; polyvinylidene chloride; polystyrenes and polystyrene copolymers (styrene-maleic anhydride copolymers, styrene acrylonitrile copolymers); nylons; polyesters such as poly(ethylene terephthalate), polyethylene butyrate and polyethylene naphthalate; polyamides such as poly(hexamethylene adipamide); polyurethanes; polycarbonates; poly(vinyl alcohol); ketones such as polyetheretherketone; polyphenylene sulfide; polyacrylates; cellulosics; fluoroplastics; polysulfones; silicone polymers; and mixtures thereof.

Thermoplastic polymers suitable for use in embodiments of the present disclosure are commercially available. Illustrative examples include those from BASF Corporation, under the trade designation “STYROFLEX”; from Kraton Performance Polymers, Inc., under the trade designation “KRATON” (e.g., KRATON D1114, KRATON MD6748, KRATON G1645); from Dow Chemical Company, under the trade designation “PELLETHANE”, “ENGAGE”, “INFUSE”, VERSIFY”, or “NORDEL”; from Royal DSM N.V., under the trade designation “ARNITEL”; from E. I. duPont de Nemours and Company, under the trade designation “HYTREL”; and from ExxonMobil under the trade designation “VISTAMAXX”. In some embodiments, the thermoplastic polymer may comprise a polyurethane copolyester elastomer. In some preferred embodiments, the thermoplastic polymer may comprise a triblock copolymer, such as, for example, KRATON D1114, KRATON MD6748, and KRATON G1645.

Mixtures of any of the above-mentioned polymers may be useful in embodiments disclosed herein. For example, a polyolefin may be blended with an elastomeric polymer to lower the modulus of the polymeric composition, which may be desirable for certain applications. In some embodiments, an additional material, such as, for example, a tackifier, a coloring agent (e.g., a color concentrate), or may be added to the thermoplastic polymer during compounding to effect a desired modification of one or more functional or aesthetic characteristics of the web contact layer. In some embodiments the web contact layer may include up to 1 wt. %, up to 2 wt. %, up to 3 wt. %, up to 4 wt. %, up to 5 wt. %, up to 6 wt. %, up to 7 wt. %, up to 8 wt. %, up to 9 wt. %, up to 10 wt. %, up to 15 wt. %, or up to 20 wt. % of a tackifier. A tackifier useful in embodiments of the present disclosure, WINGTACK PLUS, is available commercially from Total Cray Valley, Exton, Pennsylvania, U.S.A.

A variety of techniques have been used to prepare articles with structured (e.g., microstructured) surfaces and are known to those of ordinary skill in the relevant arts. Typically, the layer surface is contacted to a structured tool or release liner to form a structured pattern in the layer. For example, in U.S. Pat. No. 6,315,651 (Mazurek et al.) microstructured pressure sensitive adhesives are formed by molding an adhesive layer against a microstructured tool or a microstructured liner, and in U.S. Pat. Pub. No. 2006/0188704 (Mikami et al.) structures are formed in an adhesive surface by contacting the adhesive with a structured release tool or a structured release liner.

Referring to FIG. 2, the second major surface 27 of the web contact layer 20 has a structured surface comprising a plurality of protrusions 25 extending a height H above the land height L and having a width (e.g., diameter) W and pitch P (i.e., the average value of a distance between similar structural points of adjacent structures). The protrusions 25 may have a hemispherical shape, as shown, but other geometries, such as, for example, a sphere, a cylinder, a cone, a pyramid, and combinations thereof, are contemplated. Protrusion 25 typically has an average height of 50 μm to 600 μm and an average width or diameter of 25 μm to 760 μm. The protrusions 25 may be formed with an embossed pattern where there is a single pitch P, as shown in FIG. 6. In some embodiments, protrusions 25 may be formed with an embossed pattern having more than a single pitch P. In embodiments of the present disclosure, the structured surface commonly includes protrusions 25 at a density of 15 protrusions/cm²to 620 protrusions/cm², desirably 45 protrusions/cm²to 400 protrusions/cm², preferably 90 protrusions/cm²to 350 protrusions/cm², or more preferably 100 protrusions/cm²to 320 protrusions/cm²(e.g., 105 protrusions/cm²to 310 protrusions/cm²).

As will be understood, core coverings of the present disclosure may be made with a wide range of properties useful in differing embodiments for eliminating core impressions in films of relatively different thickness and stiffness. Additionally, the wide range of properties would also be able to accommodate different winding systems and winding tensions to reduce or eliminate core impressions. Core coverings of the present disclosure may be fabricated to provide a wide range of compression properties by varying, for example, the materials and thicknesses of the layers comprising the winding core covering, the type and amount of deviation from planar at the interface between the support layer and the web contact layer, as well as the geometry, dimensions, and number of protrusions per square centimeter on the structured surface of the web contact layer.

In another aspect, a winding core 41 including a winding core covering 10 as described supra is provided. FIG. 4 is a cross sectional view of a winding core 41 prepared according to the present disclosure. The winding core 41 includes a cylindrical tube 110 having center of rotation 115, inner surface 112, and outer surface 114 on which is disposed a winding core covering 10. The adhesive layer 40 first major surface 46 (i.e., the inner surface of the winding core covering 10) is facing outer surface 114 of cylindrical tube 110 and is joined at flush seam 50. Outer surface 48 of winding core covering 10 is facing outward, presented to engage with the web (not shown) to be wound on winding core 41. In the embodiment shown in FIG. 4, winding core 41 is of hollow tube construction.

In use, inside surface 112 of tube 110 is typically engaged with or mounted onto the mandrel of a film winding apparatus (not shown). In typical embodiments, the cylindrical tube of winding cores of the invention is a hollow tube with two open ends. However, as will be understood, in some embodiments if desired, the cylindrical tube may be solid, with or without openings or other features at one or both ends for engagement with winding or other handling apparatus.

In use, as shown in FIG. 5, when web 120 is wound upon winding core 41 having winding core covering 10, leading end 122, which can desirably be located at any position around the winding core 41 is compressed into winding core covering 10 such that subsequent layers or windings of web 120 over end 122 are subjected to stress to a lesser degree than would otherwise be the case, thereby reducing the dimension of impression stress region 130. Accordingly, web 120 will undergo formation of impressions only to a reduced degree.

Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

EXAMPLES

Unless otherwise noted or readily apparent from the context, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight.

TABLE 1

Materials

Abbreviation
Description and Source

LDPE 1
A medium molecular weight distribution Low Density Polyethylene

Resin, obtained under the trade designation “DOW 9551” from The

Dow Chemical Company, Midland, MI, USA

Triblock
A linear triblock copolymer based on styrene and isoprene with a

Copolymer 1
polystyrene content of 19%, obtained under the trade designation

“KRATON D1114” from Kraton Polymer U.S. LLC, Houston, TX,

USA

Triblock
A mixture of Styrene-Ethylene/Butylene-Styrene Polymer and

Copolymer 2
Additives, obtained under the trade designation “KRATON

MD6748” from Kraton Polymer U.S. LLC, Houston, TX, USA

Triblock
A linear triblock copolymer based on styrene and ethylene/butylene

Copolymer 3
with a polystyrene content of 11.5-13.5%, obtained under the trade

designation “KRATON G1645” from Kraton Polymer U.S. LLC,

Houston, TX, USA

Film 1
2 mil (51 micron) thick, biaxially oriented polyethylene

terephthalate (“PET”) film, made in-house by conventional means

Splice
A 5.4 micron thick double-sided adhesive tape with a 4.2 micron

Tape 1
polycoated kraft liner. Obtained under the trade designation “3M

REMOVABLE REPOSITIONABLE DOUBLE COATED TAPE

9425HT” from 3M Company, Saint Paul, MN, USA

Nonwoven
White PET Nonwoven scrim with a denier of 70 × 150. Obtained as

Backing 1
“CLOTH POLYESTER NONWOVEN STYLE 490 70 × 150

DENIER, 22 × 10 THREADS/IN, 31 IN” from Milliken,

Spartanburg, SC., USA

Fiber Core
Cardboard, 6.0 in (15.2 cm) inner diameter, 6.5 inch

(16.5 cm) outer diameter

Test Methods
Example Evaluations

Evaluations were made using samples of the core covering assemblies of Examples 1-6. A core covering assembly was installed onto a Fiber Core such that it covered the outer diameter of the core to a width greater than that of the film to be wound onto the Fiber Core. (See FIG. 4) A flush seam was prepared using techniques known to those of ordinary skill in the relevant arts. The tension was estimated to be about 1.5 pli (2.63 N/cm) and approximately constant. Any core defects or seams were marked on the exposed margin of the core for easy identification once the film was wound in place. The core bearing a core covering assembly was placed onto a center-driven, gap winder DIENES web line, where 1,200 feet (400 lineal yards; 366 m) of Film 1, at 1.5 pli (pounds-force per lineal inch; 2.6 N/cm) tension, was wound onto each core. Winding tension was measured and controlled by use of two rollers that had load cells, application of the brake on the unwind station for the roll of Film 1 and use of a nipped pull roll. The location of the leading edge of the web of Film 1 onto the covered core was marked on the exposed margin of the core for easy identification once the film was fully wound in place. Wound roll specimens so obtained were conditioned by storing for at least one week, in the same interior building location, making use of plastic end caps to avoid increased surface pressure. No differences were found between a roll stored for one week and a roll stored for longer.

Comparative Example C1

A strip of Splice Tape 1 about 2 inches (5.08 cm) wide was installed onto a Fiber Core such that it covered the width of the core to a width greater than that of the film to be wound onto the core. Any core defects and the edges of Splice Tape 1 were notated on the exposed margin of the core for easy identification once film was wound in place. The covered core was then placed onto a DIENES winder of a web line where 1,100 feet (335.3 m) of Film 1, at 1.5 pli (2.63 N/cm) tension, was wound onto the core. Winding tension was measured and controlled by use of two rollers that had load cells, application of the brake on the unwind station for the roll of Film 1 and use of a nipped pull roll. The location of the leading edge of the web of Film 1 onto Splice Tape 1 was marked on the exposed margin of the core for easy identification once the film was fully wound in place. The wound roll specimen so obtained was conditioned by storing for at least one week, making use of plastic end caps to avoid increased surface pressure. No differences were found between a roll stored for one week and a roll stored for longer.

Evaluation of Winding Impressions

Winding impressions were evaluated for each of the Examples 1-6 and Comparative Example C1. For each roll to be tested, after the minimum of one-week conditioning time, the film was unwound, and a visual inspection was performed by two evaluators. The wound roll of film was pre-marked on one of its circular ends, with a SHARPIE marker, at measurements of ⅛, ¼, ½, ¾, 1, 1¼, 1½, and 1¾ inch (3.2, 6.4, 12.7, 19.1, 25.4, 31.8, 38.1, and 44.5 mm, respectively) from the outer diameter of the core. These measurements were made with a calibrated, metal ruler. The film was unwound from the roll until the first marked interval, and the web line was stopped. The evaluated film location may be up to plus-or-minus 1/16 inch (1.6 mm) from the measured location based on stopping time notification and web line inertia. The film web was cut at the stopped location and a minimum of two diameter wraps of film was pulled away from the wound roll for examination. Any premask on the pulled-out portion of the film web was removed. Evaluators examined the length of the pulled-out film sample. The web was marked with a SHARPIE marker at observed impressions or defects. The web was carefully spliced back into the originally cut location. The web was slowly re-wound onto the original wound roll and marked observed impressions or defects were compared to the core's originally noted leading edge, seam, or core defect locations. A defect was considered visible, if it was marked as observed in at least two locations that coincided with the appropriate core noted location, once the evaluated film web was completely re-wound.

Example 1: Core Covering Assembly 1

Triblock Copolymer 1 was extrusion coated onto Nonwoven Backing 1 on an extruder line with the die slot set for about 15 mils by methods known to those of ordinary skill in the relevant arts. Nonwoven Backing 1 was utilized to give the product stability to be pulled through the manufacturing line. The polymer layer included a base or “land” layer, with features created therein by taking the extruded web and nipping it through rolls that included a rubber chilled roll including a pattern design to provide a polymer assembly. The feature density was 300 features per square inch (46.5 features per cm²). Splice Tape 1 was cut to the size of the polymer assembly and was applied to the uncoated side of Nonwoven Backing 1, i.e., the support layer, to provide the core covering assembly (see FIG. 2). The construction was:

- Backing Thickness: 8.5 mil (216 microns)
- Web Contact Layer:
  - Land Thickness: 10 mil (254 microns)
  - Feature Height: 7.6 mil (193 microns)
  - Feature Width: 22 mil (559 microns)

Example 2: Core Covering Assembly 2

A dual layer micro-replicated web was co-extruded on an extruder line (line speed: 6 fpm; die temperature: 430° F.; tool temperature: 160° F.). The bottom layer polymer, i.e., a portion of the backing layer, was LDPE 1, which gave the cooled product stability. The top layer polymer was made with Triblock Copolymer 1 and included a land layer with features created by taking the extruded web and nipping it through rolls that included a rubber chilled roll with pattern design as described in Example 1. The features density was 625 features per square inch (97.0 feature per cm²). Splice Tape 1 was cut to the size of the polymer/backing assembly and was applied to the LDPE1 layer, i.e., the backing layer of the polymer/backing assembly, to provide the core covering assembly (see FIGS. 3A and 3B). The construction was:

- Backing Thickness: 5 mil (127 microns)
- Web Contact Layer:
  - Land Thickness: 9 mil (229 microns)
  - Feature Height: 9-12 mil (229-305 microns)
  - Feature Width: 15.5 mil (394 microns)

Example 3: Core Covering Assembly 3

A dual layer micro-replicated web was co-extruded on an extruder line A dual layer micro-replicated web was co-extruded on an extruder line (line speed: 6 fpm; die temperature: 460° F.; tool temperature: 160° F.) as described in Example 2. The bottom layer polymer, i.e., the backing layer, was LDPE 1, which gave the cooled product stability. The top layer polymer was made with Triblock Copolymer 3 and included a land layer, with features created by taking the extruded web and nipping it through rolls that included a rubber chilled roll with pattern design as described in Example 1. The features density was 625 features per square inch (97.0 features per cm²). Splice Tape 1 was cut to the size of the polymer/backing assembly and was applied to the LDPE1 layer, i.e., the backing layer of the polymer/backing assembly, to provide the core covering assembly (see FIGS. 3A and 3B).

The construction was:

- Backing Thickness: 5 mil (127 microns)
- Web Contact Layer:
  - Land Thickness: 10-11 mil (254 microns)
  - Feature Height: 10-12 mil (127 microns)

Example 4: Core Covering Assembly 4

A dual layer micro-replicated web was co-extruded on an extruder line (line speed: 6.5 fpm; die temperature: 430° F.; tool temperature: 160° F.) as described in Example 2. The bottom layer polymer, i.e., the backing layer, was LDPE 1, which gave the cooled product stability. The top layer polymer was made with Triblock Copolymer 2 and included a land layer, with features created by taking the extruded web and nipping it through rolls that included a rubber chilled roll with pattern design as described in Example 1. The features density was 625 features per square inch (97.0 features per cm²). Splice Tape 1 was cut to the size of the polymer/backing assembly and was applied to the LDPE1 layer, i.e., the backing layer of the polymer/backing assembly, to provide the core covering assembly (see FIGS. 3A and 3B).

The construction was:

- Backing Thickness: 6-7 mil (152-178 microns)
- Web Contact Layer:
  - Land Thickness: 7-8 mil (178-203 microns)
  - Feature Height: 9-13 mil (229-330 microns)

Example 5: Core Covering Assembly 5

A dual layer micro-replicated web was co-extruded on an extruder line (line speed: 5.5 fpm; die temperature: 430° F.; tool temperature: 170° F.) as described in Example 2. The bottom layer polymer, i.e., the backing layer, was LDPE 1, which gave the cooled product stability. The top layer polymer was made with Triblock Copolymer 1 and included a land layer, with features created by taking the extruded web and nipping it through rolls that included a rubber chilled roll with pattern design as described in Example 1. The features density was 1600 features per square inch (248 features per cm²). Splice Tape 1 was cut to the size of the polymer/backing assembly and was applied to the LDPE1 layer, i.e., the backing layer of the polymer/backing assembly, to provide the core covering assembly (see FIGS. 3A and 3B).

The construction was:

- Backing Thickness: 5 mil (127 microns)
- Web Contact Layer:
  - Land Thickness: 10 mil (254 microns)
  - Feature Height: 8-9 mil (203-229 microns)

Example 6: Core Covering Assembly 6

A dual layer micro-replicated web was co-extruded on an extruder line (line speed: 7 fpm; die temperature: 380° F.; tool temperature: 80° F.) as described in Example 2. The bottom layer polymer, i.e., the backing layer, was LDPE 1, which gave the cooled product stability. The top layer polymer was made with Triblock Copolymer 1 and included a land layer, with features created by taking the extruded web and nipping it through rolls that included a rubber chilled roll with pattern design as described in Example 1. The features density was 1000 features per square inch (155 features per cm²). Splice Tape 1 was cut to the size of the polymer/backing assembly and was applied to the LDPE1 layer, i.e., the backing layer of the polymer/backing assembly, to provide the core covering assembly (see FIGS. 3A and 3B).

The construction was:

- Backing Thickness: 6-7 mil (152-178 microns)
- Web Contact Layer:
  - Land Height: 11-13 mil (279-330 microns)
  - Feature Height: 4-6 mil (102-152 microns)

Test Results

Core covering assemblies of Examples 1-6 and Comparative Example C1, were subjected to the test methods as described supra. On the C1 core, visual defects were identified up to 0.25 inches (6.35 millimeters) from the core covering radius. In contrast, film wound on the cores having core covers of the present disclosure incurred visual defects 0.01 inches (0.25 millimeters) from the core covering radius using the covers from Examples 2-6 and 0.125 inches (3.175 millimeters) from the core covering radius using the cover from Example 1. Results are shown in Table 2.

TABLE 2

Visual Defects Analysis Results

Leading Edge
Visible Leading-Edge Impression

Core Hold
(inch (mm) from Outer Core)

Example 1
0.125 (3.175)

Example 2
0.01 (0.25)

Example 3
0.01 (0.25)

Example 4
0.01 (0.25)

Example 5
0.01 (0.25)

Example 6
0.01 (0.25)

Comp. Ex. C1
0.250 (6.35)

All cited references, patents, and patent applications in the above application for letters patent are herein incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control. The preceding description, given in order to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto.

WOUND ROLL CORE COVERING

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