Method of producing a multi-layered printed absorbent article
09801762 · 2017-10-31
Assignee
Inventors
Cpc classification
B41M3/008
PERFORMING OPERATIONS; TRANSPORTING
Y10T156/1084
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
B32B5/26
PERFORMING OPERATIONS; TRANSPORTING
B41J11/70
PERFORMING OPERATIONS; TRANSPORTING
B32B2307/726
PERFORMING OPERATIONS; TRANSPORTING
B32B5/08
PERFORMING OPERATIONS; TRANSPORTING
Y10T156/1052
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B2307/4023
PERFORMING OPERATIONS; TRANSPORTING
B32B2262/14
PERFORMING OPERATIONS; TRANSPORTING
Y10T156/1074
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B38/0004
PERFORMING OPERATIONS; TRANSPORTING
B32B5/00
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15699
HUMAN NECESSITIES
B32B5/22
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15764
HUMAN NECESSITIES
A61F13/84
HUMAN NECESSITIES
D04H1/4374
TEXTILES; PAPER
B32B2262/02
PERFORMING OPERATIONS; TRANSPORTING
International classification
B32B5/26
PERFORMING OPERATIONS; TRANSPORTING
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
D04H1/4382
TEXTILES; PAPER
D04H1/4374
TEXTILES; PAPER
A61F13/514
HUMAN NECESSITIES
B32B5/00
PERFORMING OPERATIONS; TRANSPORTING
B32B5/02
PERFORMING OPERATIONS; TRANSPORTING
A61F13/84
HUMAN NECESSITIES
A61F13/513
HUMAN NECESSITIES
A61F13/15
HUMAN NECESSITIES
B32B5/22
PERFORMING OPERATIONS; TRANSPORTING
B32B38/00
PERFORMING OPERATIONS; TRANSPORTING
B32B5/08
PERFORMING OPERATIONS; TRANSPORTING
B41J11/70
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method for producing a multi-layered absorbent article is disclosed. At least two of the layers include a colored region.
Claims
1. A method of producing a multi-layered absorbent article having two or more colored regions, the absorbent article comprising a lateral centerline and a longitudinal centerline, the method comprising the steps of: a. providing an absorbent article converting line; b. supplying a first precursor web to the converting line; c. printing a first colored region to the precursor web using contact printing at a contact printing station; d. supplying a second precursor web material; e. printing a second colored region to the second precursor web material using non-contact printing at a non-contact printing station, wherein the first colored region is laterally more extensive than the second colored region and wherein the first colored region and the second colored region are longitudinally spaced apart; f. supplying an absorbent core web and a backsheet web; g. cutting the second precursor web and the absorbent core web creating individual sheets of the second precursor web and individual sheets of the absorbent core web; h. placing the individual sheets of the second precursor web and the absorbent core web onto the first precursor web; i. combining the backsheet web with the first precursor web such that the individual sheets of second precursor web and absorbent core web are disposed between the first precursor web and the backsheet web, thereby forming an absorbent article web; and j. cutting the absorbent article web into individual absorbent articles.
2. The method of claim 1, wherein the first colored region and the second colored region do not overlap with one another.
3. The method of claim 1, wherein the contact printing is done using a flexographic printing process.
4. The method of claim 1, wherein the non-contact printing is done using an ink jet process.
5. The method of claim 1, wherein the first precursor web and the second precursor web are supplied to the converting line concurrently.
6. The method of claim 1, wherein the absorbent article is a feminine sanitary napkin having a central region and a periphery.
7. The method of claim 6 wherein the second colored region is disposed in the central region of the feminine sanitary napkin and the first colored region between the second colored region and the periphery of the feminine sanitary napkin.
8. The method of claim 7, wherein the second colored region extends along the longitudinal centerline.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
DETAILED DESCRIPTION OF THE INVENTION
(8) The present invention relates to a method of producing a printed multi-layered absorbent article on a converting line. A first substrate, such as a topsheet, is supplied to a converting line and printed with a first colored region using a contact method of printing, for instance, flexographic printing, rotogravure printing, offset printing, lithographic printing, screen printing, or the like. A second substrate, such as a non-woven or cellulose based secondary topsheet is also supplied to the converting line and printed with a second colored region using a non-contact method of printing, such as, for example, wax jet printing, ink jet printing, bubble jet printing, laser jet printing, or the like. Following the printing steps the first substrate and second substrate are combined in the process of producing an absorbent article, such as a feminine sanitary napkin.
(9) As used herein the term “converting line” means a manufacturing line used to make absorbent articles. The purpose of a converting line is to take raw materials, process and combine them to produce absorbent articles. A converting line comprises various unit-operations used in the production of absorbent articles. A unit-operation can range from simple actions such as raw material transport (unwind, meter, reposition, and the like) to complex material transformations (melting, cutting, stretching, fluid application (ink, lotion, adhesive), and the like). In the converting line many unit-operations are occurring in parallel as well as in sequence to produce an absorbent article.
(10) As used herein, the term “print” or “printing” means to produce a colored region on a substrate. Frequently, printing involves formation of a colored region by the transfer of pigment, colorant, or brightener in the form of ink, wax, paint, or the like to a substrate. The printed colored region is visible to the human eye and can include, for example, shapes, patterns, designs, objects, likenesses of real or fictitious characters, or the like, or combinations thereof. Examples of printing methods include contact printing and non-contact printing. Contact printing includes the direct transfer of pigment from a print roll, plate, or screen to a substrate. In non-contact printing methods, the printing apparatus does not directly contact the substrate, for example when printing from ink jet printers, wax jet printers, bubble jet printers, laser jet printers, or the like, or combinations thereof.
(11) As used herein, the term “substrate” means a web of material capable of moving through a converting line. A substrate can include contiguous material wherein individual units of material are connected or directly joined to the immediately preceding and trailing units of material. For example, a substrate may include a continuous web of woven material, nonwoven material, film, or the like, or combinations thereof. A substrate may also include interconnected absorbent articles in various stages of manufacture. A substrate may also include a web of discrete units of material separated by space or by other materials. For example, a substrate may include discreet absorbent articles moving through a converting line via one or more conveyor belts or other means of conveyance known in the art.
(12) As used herein, the phrase “absorbent article” refers to devices which absorb and contain fluids, which includes bodily fluids, and more specifically refers to devices which may be placed against or near the skin to absorb and contain the various fluids discharged from the body. In typical use absorbent articles are not intended to be laundered or otherwise restored or reused after a single use. Examples of absorbent articles include, but are not limited to sanitary tissue products, for example facial tissue, toilet tissue, paper towels, wipes; home care products, for example cleaning wipes, such as Swiffer® (The Procter & Gamble Company, Cinc., Ohio); beauty care products such as wipes and cleaning pads; feminine hygiene products, for example sanitary napkins, pantiliners, tampons, interlabial devices and the like; infant diapers; children's training pants; adult incontinence products. Non-limiting examples of pantiliners and sanitary napkins which may be provided with a first colored region on a laminate substrate and second colored region on a lower substrate include those manufactured by The Procter & Gamble Company of Cincinnati, Ohio, such as ALWAYS ULTRA, ALWAYS INFINITY, and ALWAYS pantiliners. Absorbent articles such as those disclosed in U.S. Pat. Nos. 4,324,246, 4,463,045, 6,004,893, 4,342,314, 4,463,045, 4,556,146, 4,589,876, 4,687,478, 4,950,264, 5,009,653, 5,267,992, and Re. 32,649 are also contemplated as being absorbent articles that might benefit from a first and second colored region.
(13) Absorbent articles, and their individual components, such as a liquid pervious topsheet, a secondary topsheet, an absorbent core, and a substantially liquid impervious backsheet, have a body facing surface and a garment facing surface. As used herein, “body-facing surface” means that surface of the article or component which is intended to be disposed toward or placed adjacent to the body of the wearer during ordinary use, while the “garment facing surface” is on the opposite side, and is intended to be disposed to face away from the wearer's body during ordinary use. The garment facing surface may be arranged to face toward or placed adjacent to the wearer's undergarments when the absorbent article is worn. In general the topsheet is operatively permeable to the liquids that are intended to be held or stored by the absorbent article, and the backsheet may be substantially impermeable or otherwise operatively impermeable to the intended liquids. The absorbent article may also include components such as liquid wicking layers, liquid distribution layers, barrier layers, and the like, as well as combinations thereof.
(14) The term ‘color’ as referred to herein includes any primary color, for example, white, black, red, blue, violet, orange, yellow, green, and indigo as well as any declination thereof or mixture thereof. The term ‘non-color’ or ‘non-colored’ refers to the color white which is further defined as those colors having an L* value of at least 80, an a* value equal to 0±2, and a b* value equal to 0±2.
(15) One embodiment of the method is illustrated in
(16) With reference to
(17) In one embodiment, the contact printing station 103 for printing a first colored region on a first substrate can comprise a flexographic printing process 105, as shown in
(18) As the first substrate 101 enters the printing nip 119 formed by the operational relationship of the surfaces of the plate roller 113 and the central impression roller 117, the ink 107 on the surface of the plate roller 113 makes contact with, and is transferred to, the first substrate 101.
(19) Alternatives to the described flexographic printing process can also be used in the contact printing station of the present invention. For example, in certain embodiments, the contact printing station may comprise a gravure printing process 131 as illustrated in
(20) As shown in
(21) As shown in
(22) The first and the second print heads 153 and 155 can be any type that is suitable to print a colored region, and may be disposed at a certain suitable distance from the second substrate 141. In certain embodiments the distance may be form about 0.5 mm to about 3 mm, and in certain other embodiments from about 1 mm to about 2 mm. In certain embodiments, the inkjet printing station may comprise one or more digital printers, such as a continuous binary array allowing for a greater ink drop velocity than other inkjet printers, allowing for a wider gap between the print head and web to provide a quality image.
(23) The print heads 153 and 155 can be supplied with ink from a common ink source; although in certain embodiments, separate ink sources can be also utilized.
(24) Each of the print heads 153 and 155 includes a multiplicity of jets dispensing a multiplicity of substantially uniform ink dots. In one embodiment of the present invention, each of the print heads 153 and 155 can include 256 jets, forming a linear configuration in the cross-direction of about 2 inches long (about 50.8 mm) Therefore, each of the print heads 153 and 155 can print an ink image containing 256 ink dots extending linearly about 50.8 mm across the second substrate 141. This arrangement is sufficient for printing any image of up to about 50.8 mm wide, as measured in the cross-direction of the second substrate 141. However, any number of jets per a print head can be provided to print a desired width W of a colored region, which in certain embodiments, for absorbent articles produced in the process of the present invention can vary from about 5 mm to about 185 mm, in certain other embodiments from about 20 mm to about 105 mm.
(25) With respect to the print heads having 256 jets, such print heads are available from Videojet Technologies, Inc., (Wood Dale, Ill.). The printing station 143 can be a part of an inkjet printing system that is also available from Videojet Technologies, Inc., as the BX6000 series inkjet print system including an ink source and a controller for providing ink and controlling jets forming individual ink droplets.
(26) In the BX6000 series inkjet print system a continuous binary array can be used, wherein the ink droplets are dispensed from all of the jets of the print heads 153 and 155 continuously, but only certain ink droplets are allowed to reach the second substrate 141 at desired locations to form a printed image. The other ink droplets can be prevented from reaching the second substrate 141 by deflecting the ink droplets into a recycling flow for a continuous re-use. The operation of the individual ink jets of each print head can be controlled by a controller included in the BX6000 series system.
(27) In certain embodiments, in place of a continuous type of the inkjet printing system the inkjet printing system can be an on-demand type inkjet printing system (such as thermal ink jet or Peizo Drop on Demand), wherein ink typically is not recycled and ink droplets are formed on a demand basis and in a desired order to print a colored region.
(28) Referring again to
(29) Referring again to
(30) Referring now to
(31) In certain embodiments the topsheet, secondary topsheet, or both may be compliant, soft feeling, and non-irritating to the wearers skin and hair. Further, the topsheet or secondary topsheet is liquid pervious, permitting liquids, such as menses or urine, to readily penetrate through its thickness. A suitable topsheet or secondary topsheet may be manufactured from a wide range of materials such as woven and nonwoven materials, for example a nonwoven web of fibers; polymeric materials such as apertured formed thermoplastic films, apertured plastic films, and hydroformed thermoplastic films; porous foams; reticulated foams; reticulated thermoplastic films; and thermoplastic scrims. Suitable woven and nonwoven materials can be comprised of: natural fibers, such as wood or cotton fibers; synthetic fibers, such as polymeric fibers—for example polyester, polypropylene, or polyethylene fibers; or from a combination of natural and synthetic fibers. When the topsheet or secondary topsheet comprises a nonwoven web, the web may be manufactured by a wide number of known techniques. For example, the web may be spunbonded, carded, wet-laid, melt-blown, hydroentangled, combinations of the above, or the like.
(32) The backsheet is substantially impervious to liquids, such as menses or urine and may be manufactured from a thin plastic film, although other flexible liquid impervious materials may also be used. The backsheet prevents the exudates absorbed by the absorbent core from wetting a user's bedding or clothes, for example bedsheets, pants, pajamas and undergarments. In certain embodiments, the backsheet can operatively permit a sufficient passage of air and moisture vapor out of an absorbent article, particularly out of the absorbent core, while blocking the passage of bodily liquids. The backsheet may thus comprise: a woven or nonwoven material; polymeric films, such as thermoplastic films of polyethylene or polypropylene; or composite materials such as a film-coated nonwoven material. In one embodiment, the backsheet can be a breathable backsheet such as that described in U.S. Pat. No. 6,623,464 (Bewick-Sonntag et al.) issued 23 Sep. 2003.
(33) As shown in
(34) The absorbent core 60 in
(35) The absorbent core may also include one or more superabsorbent materials. Superabsorbent materials suitable for use in the present invention are known to those skilled in the art, and may be in any operative form, such as particulate form. The superabsorbent material can be a water-swellable, generally water-insoluble, hydrogel-forming polymeric absorbent material, which is capable of absorbing at least about 20, in certain embodiments about 30, and in additional embodiments about 60 times or more its weight in physiological saline (for example 0.9 wt % NaCl). The hydrogel-forming polymeric absorbent material may be formed from organic hydrogel-forming polymeric material, which may include natural material such as agar, pectin, and guar gum; modified natural materials such as carboxymethyl cellulose, carboxyethyl cellulose, and hydroxypropyl cellulose; and synthetic hydrogel-forming polymers. Synthetic hydrogel-forming polymers include, for example, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, ethylene maleic anhydride copolymers, polyvinyl ethers, polyvinyl morpholinone, polymers and copolymers of vinyl sulfonic acid, polyacrylates, polyacrylamides, polyvinyl pyridine, and the like. Other suitable hydrogel-forming polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel-forming polymers are preferably lightly crosslinked to render the material substantially water insoluble. Crosslinking may, for example, be by irradiation or covalent, ionic, Van der Waals, or hydrogen bonding. Suitable materials are available from various commercial vendors, such as the Dow Chemical Company and Stockhausen, Inc. The superabsorbent material may be included in an appointed storage or retention portion of the absorbent article, and may optionally be employed in other components or portions of the absorbent article.
(36) As shown in
(37) When the body facing surface 204 of the feminine sanitary napkin 200 is viewed, the feminine sanitary napkin 200 can have a background region 214. The background region 214 is a region that is visually distinguishable from the first colored region 216 and second colored region 218. The background region 214 can be white or any other color visually distinguishable from the first colored region 216 and second colored region 218. Colors are believed to be visually distinguishable if there is a □E between the two colors of at least about 1.
(38) The topsheet 208 comprises the first colored region 216. The first colored region 216 can be the constituent color of the topsheet 208 with the background region 214 rendered to have a color that differs from the constituent color of the topsheet 208. The first colored region 216 can be provided on, for instance, the body facing side of the topsheet 208 or the garment facing side of the topsheet 208. Similarly, the secondary topsheet 41 comprises the second colored region 218. The second colored region 218 can be the constituent color of the secondary topsheet 41 with the background region 214 rendered to have a color that differs from the constituent color of the secondary topsheet 41. The second colored region 218 can be provided on, for instance, the body facing side of the secondary topsheet 41 or the garment facing side of the secondary topsheet 41. The second colored region 218 can be coincident with the longitudinal centerline L. That is, a portion of the second colored region 218 can intersect with the longitudinal centerline L.
(39) When the body facing surface 204 is viewed, the background region 214, first colored region 216, and second colored region 218 are viewable by an observer. The first colored region 216 and second colored region 218 are visibly distinct from the background region 214 in that first colored region 216 and second colored region 218 each differ in color as compared to the background region 214. The first colored region 216 and the background region 214 can differ in color by a □E, which is discussed in more detail below, of at least about 1. The first colored region 216 and the background region 214 can differ in color by a □E, which is discussed in more detail below, of at least about 3, if more visual distinctiveness is desired.
(40) Similarly, the second colored region 218 and the background region 214 can differ in color by a ΔE of at least about 1. The first colored region 216 and the second colored region 218 can both differ in color as compared to the background region 214 by a ΔE of at least about 1. The first colored region 216 and the second colored region 218 can be more visually distinguishable if there is a ΔE between the two colors of at least about 3.
(41) As shown in
(42) The first colored region 216 can be designed so as to be visually complementary to the second colored region 218 and be presented to the viewer over a wider/more extensive portion of the body facing surface 204. It is thought that by having the first colored region 216 on a different layer of material than the second colored region 218 that a richer visual impression can be created on the feminine sanitary napkin 200. For instance, since the first colored region 216 and second colored region 218 are on different layers of materials, when viewed, at least one of the colored regions will be viewed through the layer comprising the other colored region. A colored region viewed through another layer material can have a significantly different visual impression in terms of softness/diffuseness of the image, somewhat like the difference between a matte finished photograph versus a gloss finished photograph.
(43) Further, if the second colored region 218 is provided by inkjet printing, the design of the second colored region 218 can be easily changed so that feminine sanitary napkins 200 within a single package or different packages can have different designs for the second colored region 218. The first colored region 216 might be provided by a contact printing apparatus that cannot be easily altered. Thus, the first colored region 216 can be a constant design recognizable by consumers as being a product from a particular brand or of a particular quality.
(44) A first colored region 216 that is laterally more extensive than the second colored region 218 can also provide the impression to the wearer that such laterally more extensive portions of the feminine sanitary napkin 200 are capable of acquiring and retaining fluid. For instance, if the first colored region extends across a substantial portion of the feminine sanitary napkin 200 in the cross-direction CD, viewers of the feminine sanitary napkin 200 may interpret the first colored region 216 as providing a barrier to fluid flow beyond the first colored region 216 or a boundary beyond which the user should not expect fluid to pass as the fluid travels in the machine-direction MD of the feminine sanitary napkin 200.
(45) The second colored region 218 can be coincident with the central region 202. The central region 202, being the in-plane center of mass of the feminine sanitary napkin 200, might be associated by the user as being the location of the feminine sanitary napkin 200 that should be proximal her vaginal opening or urethra. Designs in which the second colored region 218 is symmetric about the longitudinal centerline may provide for a more pleasing impression of the feminine sanitary napkin 200 than designs in which the second colored region 218 is not symmetric with respect to the longitudinal centerline L.
(46) As shown in
(47) As shown in
(48) The second colored region 218, as shown in
(49) The first colored region 216 can be substantially arcuate shaped. Arcuate shaped first colored regions 216 are thought to be perceived by users as barriers to flow of liquid in the absorbent article or as providing an indication to a user that they may not want fluid to pass beyond such a colored region or that once such fluid flow has occurred they may want to be prepared to wear a fresh product in the near future.
(50) Arcuate shapes include, but are not limited to, shapes generally corresponding to those found on common keyboards including the greater than symbol, parenthesis, circumflex (also referred to as the caret symbol), and bracket as well as generally c-shaped shapes, and slight modifications of any of these previously mentioned shapes. Arcuate shapes, as defined herein, can be generally curved like a letter C or can be more angular such as the symbol <. Thus, arcuate shapes do not necessarily have any particular curvature.
(51) A cross section of the feminine sanitary napkin 200 illustrated in
(52)
(53) The color of the first colored region 216 and second colored region 218 and background region 214 are measured by the reflectance spectrophotometer according to the colors L*, a*, and b* values. The L*, a*, and b* values are measured from the body facing surface 204 of the feminine sanitary napkin 200 inboard of the periphery 220 of the feminine sanitary napkin 200. The difference in color is calculated using the L*, a*, and b* values by the formula ΔE=[(L*.sub.X.−L*.sub.Y).sup.2+(a*.sub.X.−a*.sub.Y).sup.2+(b*.sub.X−b*y).sup.2].sup.1/2. Herein, the ‘X’ in the equation may represent the first colored region 216, the second colored region 218, or the background region 214 and ‘Y’ may represent the color of another region against which the color of such region is compared. X and Y should not be the same two points of measurement at the same time. In other words, for any particular comparison of the difference in color, the location of X≠the location of Y.
(54) Where more than two colors are used, the ‘X’ and ‘Y’ values alternately include points of measurement in them also. The key to the ΔE calculation herein is that the ‘X’ and ‘Y’ values should not stem from the same measured point on the viewing surface. In those instances where there is effectively no background region 214 within the confines of the measurement area, the ‘X’ values should flow from a point different in spatial relationship to the ‘Y’ values, but within the confines of the absorbent core periphery.
(55) Reflectance color is measured using the Hunter Lab LabScan XE reflectance spectrophotometer obtained from Hunter Associates Laboratory of Reston, Va. A feminine sanitary napkin 200 is tested at an ambient temperature between 65° F. and 75° F. and a relative humidity between 50% and 80%.
(56) The spectrophotometer is set to the CIELab color scale and with a D65 illumination. The Observer is set at 10° and the Mode is set at 45/0°. Area View is set to 0.125″ and Port Size is set to 0.20″ for films. The spectrophotometer is calibrated prior to sample analysis utilizing the black glass and white reference tiles supplied from the vendor with the instrument. Calibration is done according to the manufacturer's instructions as set forth in LabScan XE User's Manual, Manual Version 1.1, August 2001, A60-1010-862. If cleaning is required of the reference tiles or samples, only tissues that do not contain embossing, lotion, or brighteners should be used (e.g., PUFFS tissue). Any sample point on the absorbent article containing the imparted color to be analyzed can be selected.
(57) The feminine sanitary napkin 200 is placed over the sample port of the spectrophotometer with a white clamp disk placed behind the feminine sanitary napkin 200. The feminine sanitary napkin 200 is to be in a substantially flat condition and free of wrinkles.
(58) The feminine sanitary napkin 200 is removed and repositioned so that a minimum of six readings of color of the body facing surface 204 are conducted. If possible (e.g., the size of the imparted color on the element in question does not limit the ability to have six discretely different, non-overlapping sample points), each of the readings is to be performed at a substantially different region on the externally visible surface so that no two sample points overlap. If the size of the imparted colored region requires overlapping of sample points, only six samples should be taken with the sample points selected to minimize overlap between any two sample points. The readings are averaged to yield the reported L*, a*, and b* values for a specified color on an externally visible surface of an element.
(59) In calculating the CIELab color space volume, V, maximum and minimum L*, a*, and b* values reported are determined for a particular set of regions to be measured. The maximum and minimum L*, a*, and b* values reported are used to calculate the CIELab color space volume, V, according to the following formula:
(60)
(61) Within the above formula, ΔL* is the difference in L* values between the two colored regions being compared and is calculated by: ΔL*=L*.sub.X−L*.sub.Y. The Δa* is the difference in a* values between the two colored regions being compared and is calculated by: Δa*=a*.sub.X−a*.sub.Y. The Δb* is the difference in b* values between the two colored regions being compared and is calculated by: Δb*=b*.sub.X−b*.sub.Y. The CIELab color space volume can result in a solid substantially ellipsoidal in shape. If ΔL*, Δa*, and Δb* are equal, the solid will be spherical. As used herein, a “solid” refers to the mathematical concept of a three-dimensional figure having length, breadth, and height (or depth). An ellipsoidal volume is preferred to calculate volume because an ellipsoid generally requires the dimensional differences of ΔL*, Δa*, and Δb* to be relatively more uniform than other solids. Furthermore, it is believed that ellipsoidal volumes are more visually acceptable (less detectable color mismatch by human perception) than spherical volumes.
(62) In some embodiments, the imparted colors of at least two externally visible surfaces of discrete elements will occupy a CIELab color space volume of less than about 200. The externally visible surfaces are analyzed according to the Test Method described below. Upon analysis, the inherent color of an element comprising an externally visible surface will yield L*, a*, and b* coordinates. The CIELab color space volume is then calculated using the formula presented above. The resulting volume can be less than about 200. The resulting volume can be less than about 50.
(63) It should be recognized that the imparted colors of more than two discrete colored regions having a visible surface may occupy the aforementioned CIELab color space volumes. In calculating the CIELab color space volume for more than two elements, the CIELab color space volume is calculated using the maximum and minimum L*, a*, and b* from a set of elements. The maximum color values and minimum color values are used to calculate V according to the formula presented above.
(64) The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”
(65) Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
(66) While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.