Method of making menstrual napkins
United States Patent 1191 1111 3,878,283 Jones, Sr. Apr. 15, 1975 [54] METHOD OF MAKING MENSTRUAL 2,847,086 8/1958 Muller 264/112 X NAPKINS 2,890,481 6/1959 Leahy et a1. 156 50o 3,088,463 5/1963 Harmon 128/290 W Inventor: John Leslie Jones, Sr., 0 0 Glen 3,403,681 10/1968 Hoey et al. 156/253 Oaks Blvd., Pasadena, Calif. 91105 3,475,249 10/1969 Smith 156/253 Filed: g 0 1 3,477,433 11/1969 D1110&#34;; 128/290 R FOREIGN PATENTS R APPLICATIONS [21] Appl&#39; 284982 1,058,635 2/1967 United Kingdom 282/1 1.5 A  
  Related US. Application Data ,1 l 1969 United Kingdom [60] (l&#39;lgysinuabtiog-in-pjart of hSer. N3. 6&#39; 7,S93,f lgug. 57, OTHER PUBLICATIONS a 3.11 one W 1C 15 a 1V1S1OI1 O 81&#39;. O. Anon., Websters Seventh New Colleglate D1ct1onary, 720500 Merriam, Springfield, Mass. (1967), page 692 relied [52] US. Cl. 264/152; 264/153; 264/156;  
  264/160; 264/251; 264/258; 264/263 51 1111. C1. A611 13/18; B32b 31/08; B32b 31/18 &#39;F f l whlte [58] Field of Search 128/290; 156/251, 253, Asmam hammer-Mum 83/688, 689; 161/110, 111,114, 115; [571 ABSTRACT 264/263, 258, 154, 157, 160, 152, 155, 251, This invention teaches a new menstrual napkin em- 297, 328, 153, 156 bodying a multiple ply tissue paper construction and an obtuse diamond pattern shape, both of these im- [56] References Cited provements adapting themselves to an improved nap- UNITED STATES PATENTS kin manufacturing PI&#39;OCCSS.  
 2,818,924 1/1958 Lang 83/689 X 4&#39; Claims, 12 Drawing Figures /z /Z /0 9 4 g Iii 81 2 21 2424 485 PMENTEUA R 1 W5 3, 878.283  
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 METHOD OF MAKING MENSTRUAL NAPKINS This is a continuation-in-part of application 67.593 filed Aug. 27. 1970. now abandoned which was a division of Ser. No. 720.500 filed Apr. 1 l. I968. now U.S. Pat. No. 3.532.097.  
 BACKGROUND OF THE INVENTION Menstrual sanitary napkins are conventionally made of ground. bleached wood pulp which has been shredded and formed into fibrous. fluffy. randomly arranged. low density rectangular shaped pads containing 8 to 9 grams of wood pulp fibers. The pads are typically 8 /4 inch longXZVz inch wideX A inch thick. The pads are typically covered with a non-woven fabric which provides a shaping and securing means for the wood pulp fibers. The non-woven fabric is formed longer than the pulp pad to provide end tabs or flat sleeves. The sleeves are used to secure the napkin to a waist belt or holder for female use.  
  The above type of sanitary napkin is bulky in the stored package. The fluffy pad of wood pulp is also bulky when used by females. Occasionally a napkin leaks menstrual fluid. The napkins do not adapt themselves to a simplified means of positioning themselves on the female torso.  
  My improvement in menstrual sanitary napkin solves problems produced by the conventional napkins.  
 SUMMARY OF THE INVENTION The menstrual sanitary napkin of this invention embodies a multiplicity of tissue paper layers adhesively bonded together in multiple ply. The multiple ply oftissue paper are bonded to a thin. flexible. fluid impermeable plastic membrane which is soft to body touch. to  
 form the secondary menstrual fluid absorptive section.  
 The primary menstrual fluid absorptive section can be composed of the above described multiple ply tissue paper or a single layer of highly compressed regenerated Cellulose sponge. The primary absorptive section is shaped to fit adjacent to and confront the vaginal vestibula area. The primary absorption section is centered on. and adhesively secured to the absorptive face of the secondary absorptive section.  
 Included in the objects of this invention are:  
  First. to provide a dry. single use. compact menstrual sanitary napkin made from inexpensive wood pulp tissue paper.  
  Second. to provide a manufacturing process for menstrual sanitary napkin. embodying means for adhesively bonding together multiple ply of tissue paper menstrual fluid absorptive means.  
  Third. to provide a thin. single use menstrual sanitary napkin adaptively conforming to and confronting a vaginal vestibula area during use.  
  Fourth. to provide a menstrual sanitary napkin having an overall planar obtuse diamond shaped area. which can be plurally manufactured simultaneously and inexpensively.  
  Fifth. to provide an adhesive bonding means suitably securing together multiple plies of tissue paper in a sanitary paper product.  
  Other objects and advantages of this invention are taught in the following description and claims.  
 BRIEF DESCRIPTION OF THE DRAWING Thedescription of this invention is to be read in conjunction with the following drawings in which:  
  FIG. 1 is a plan view of one modification of the improvement in menstrual sanitary napkin.  
 FIG. 2 IS an elevation view through 2-2 of FIG. 1.  
  FIG. 3 is a perspective detail view of a preliminary fabrication step. prior to securing together multiple ply of tissue paper.  
  FIG. 4 is a cross sectional view through 44 of FIG. 3. further explaining the fabrication steps.  
  FIG. 5 is a cross sectional view of an adhesive plug bonding means. securing together a secondary absorptive section and a thin. flexible. fluid impermeable plastic membrane.  
  FIGS. 61!. 6b. 6c and 611 are perspective plan views of other useful adhesive detent means in single ply tissue paper sheet.  
  FIG. 7 is an elevational. side view of another modification of the sanitary napkin invention. also embodying an improvement disclosed in my earlier U.S. patent application Ser. No. 675.556. filed Oct. 16. 1967. now U.S. Pat. No. 3.512.530.  
  FIG. 8 is a plan view of a multiplicity of obtuse diamond shaped absorptive sections of this invention. shown arrayed in a web pattern suitable for a manufacturing process.  
  FIG. 9 is a plan view of an obtuse diamond shape section which is a preferred shape fora primary and secondary absorptive section of this invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 in detail. a menstrual sanitary napkin l is shown in plan view to have an obtuse diamond planar shape. The primary absorptive section 4 and the secondaryv absorptive section 5 are copla-- narly. coaxially aligned around the intersection 6 of the section line 22 and the line of center 3. The primary absorptive section 4 and the secondary absorptive section 5 have the same geometrical pattern. which is designated for simplicity and clarity as an obtuse diamond shape. Both sections 4 and 5 each comprise a multiplicity tissue paper sheets. coplanarly and adjacently laid together. A thin. flexible. fluid impermeable plastic membrane 7 is shown in FIG. 2., and it is equal in area. coplanar with and forms the interface 8 with the secondary absorptive section 5. The primary absorptive section 4 and the secondary absorptive section 5 have the interface 9.  
  Suitably. the primary absorptive section 4 and the secondary absorptive section 5 each comprise a range of 20-40 sheets of bleached white wood pulp. uncalendared tissue paper. stacked in coplanar confronting layers. The tissue paper has a weight range per unit of area of typically 0.010 to 0.020 gram/sq. in. A typical absorptive section can be 30 stacked sheets of tissue paper. of weight 0.01 l gram/sq. in. Other ranges of numbers of tissue paper sheets and paper weights can be fabricated within the scope of this invention.  
  To avoid the problem of tissue paper particles being lifted off the absorptive sections 4 and 5, and deposited on the vestibular. it is desirable to terminate the face 10 of the primary absorptive section 4 and the face 11 of the secondary absorptive section 5 each with a single facing sheet of non-woven fibrous fabric of wood pulp. cotton linters or a mix of the two fibers. Suitably. the non-woven fabric is open and porous. and can have a synthetic resin content and calendered finish sufficient to prevent lint formation on its surface. The non-woven fabric weight suitably ranges from 0.005 to 0.020 gram/sq. in.  
  The essential means of securing together the multiple ply of tissue paper and non-woven fabric face sheets of sections 4 and 5 and the plastic membrane 7 are the adhesive plug bonding means 12 and 12&#39;. which are generically illustrated in FIGS. 1 and 2. The adhesive plug bonding means 12 and 12 each comprise a solid adhesive plug extending through a coaxially aligned detent means opening in a multiple ply of tissue paper. including a non-woven fabric sheet; which alternatively. may or may not terminate at an adhesive bond with a plastic membrane 7.  
  FIG. 2 shows the primary absorptive section 4 secured by adhesive plug bonding means 12&#39; extending through the secondary absorptive section 5 to bond with the plastic membrane 7. as illustrated in detail in FlGS. 3. 4 and 5. The primary absorptive section 4 can also be bonded together by fabrication steps also illustrated in FIGS. 3. 4 and 5.  
  The adhesive plug bonding means 12 and 12&#39; broadly comprise a multiplicity of coaxially aligned. adjacent adhesive detent openings in a multiplicity of tissue paper plies in which is placed and secured a hot melt adhesive plug. cooled to ambient room temperature. FIGS. 3. 4 and 5 together illustrate the fabrication of adhesive bonding means 12 and 12&#39;. As shown in perspective view in FlG. 3. the multiplicity of coplanarly stacked ply of tissue paper are shear cut by a malefemale cutting die. forming an adhesive detent triangular opening 31 in each tissue paper ply. The opening 31 has a corresponding triangular shaped tissue paper ply leaf 32. which has a leaf hinge 33 securing the leaf 32 to the ply of tissue paper. FIG. 4 illustrates in more detail the sectional view through 44 of FIG. 3. showing the stacked ply of tissue paper 30. each ply of which has a shear cut adhesive detent opening 31. formed by the leaf 32 which is attached by the hinge 33 to the single ply of tissue paper 34.  
  FIG. 5 illustrates a further modification of the structure of FIGS. 3 and 4, showing a complete adhesive plug bonding means 12 or the like. The FlGS. 3 and 4 multiple leafs 32 are flexed on their hinges 33. and the multiple stacked ply of tissue paper 30 are coplanarly and confrontingly placed adjacent the thin. flexible. fluid impermeable plastic membrane 35. A melted. hot melt. high viscosity adhesive is then injected in a controlled volume into the adhesive detent opening 3l-leaf 32 combination. which is confronted by the plastic membrane 35. The cooled solidified adhesive coheres the leaves 32. and the plastic membrane 35 into a bonded coherent whole adhesive plug bonding means l2. 12&#39; or the like. solid and non-tacky at human body temperature. The adhesive plug bonding means 12 comprises the comingled leaves 32 and the solid adhesive plug 36. together with the bonded area of plastic membrane 35.  
  In another modification of the adhesive plug bonding means. the bonding means can include only a multiplicity of leaves 32, or the like, comingled with an adhesive plug 36. or the like. located in an adhesive detent opening 32 or the like. without a confronting plastic membrane 36. This modification of the bonding means is particularly suitable in preforming the primary absorptive section 4. or the like, before securing section 4 onto the secondary absorptive section 5. or the like.  
  Although a triangular shaped adhesive detent opening 31 is shown in FIGS. 3, 4 and 5. other geometrical shaped coaxially aligned. confronting adhesive detent means fabricated in the multiple ply of tissue paper are included in this invention. FIGS. 61!. 6b. 6c and 6d show other modifications of useful adhesive detent means of this invention in perspective views in single ply oftissue paper. FIG. 6a illustrates a rectangular shaped paper leaf 40. formed in an adhesive detent opening 4l-. the leaf 40 having a hinge 42 connected to tissue paper ply 43. FIG. 6!: illustrates a circular shaped paper leaf 44 formed in an adhesive detent opening 45. the leaf 44 having a hinge 46 connected to the tissue paper ply 47. FlG. 6c illustrates a quartet of four paper leafs 48. 48&#39;. 48&#34;. 48&#34; formed about the adhesive detent cross-slit opening 49 in the tissue paper ply 50. FIG. 6d illustrates a further modification of the adhesive detent means in which a circular adhesive detent opening 51 is located in a tissue paper ply 52. there being no tissue paper leaf.  
  All of the adhesive detent means illustrated in FIGS. 6a. 6b. 6c and 6d. as well as in FIGS. 5 and 6. can be injected with a controlled volume of a hot melt adhesive filling the adhesive detent opening. providing a solid adhesive plug on cooling. which bonds the multiple ply of tissue paper together. The hot melt adhesive is selected from a chemical composition which will also adhesively bond to the confronting plastic membrane 35. or the likc. of FIG. 5.  
  The adhesive plug bonding means l2. l2 and the like. are sized to provide adhesive detent openings typically ranging from /8 to /4 inch long in a flat paper sheet linear dimension. The means 12. 12 and the like should be adaptively placed and spaced in the napkin to provide no irritation to the female torso when in use.  
  A hot melt adhesive. free from water or other solvents which readily wet tissue paper. is preferred. since the adhesive should not wet and extensively migrate through the tissue paper by capillary attraction. A hot melt adhesive is free from solvent and can be rapidly cooled to a non-tacky solid. The viscosity of the molten v adhesive should be high. in order to decrease plastic flow of the melt. A hot melt adhesive viscosity of l2,000-l 8.000 centipoise at an injection temperature of lF is typically suitable for an adhesive bonding to polyethylene. A highly plasticized vinyl chloride polymer may be used as a hot melt adhesive for a very flexible polyvinyl chloride membrane 7 or the like. Hot melt adhesives based on fatty acid polyamides. as well as adhesives based on properly formulated plasticized polyvinyl acetate and like polymers may also be utilized. It is essential the hot melt adhesives remain solid and non-tacky at human body temperature and in commercial storage. up to F or the like. Likewise. the adhesive compositions should not be toxic or tend to promote skin allergies.  
  FIG. 7 illustrates another modification ofa menstrual sanitary napkin 70 of this invention in which a side elevational view shows the several components in exaggerated scale due to drawing size limitation. The thin. flexible. fluid impermeable plastic membrane 71 is secured at the interface 72 to the secondary absorptive section 73. The planar shape of the secondary absorptive section 73 can be similar to section 5 of napkin 1.  
  In the napkin 70, the primary absorptive section 74 comprises a planar. dry. regenerated cellulose. fine pore sponge volume. whose sponge volume is dimensionally compressed normal to the planar face of the sponge volume. minimizing the pore size openings. The uncompressed. fine pore sponge volume from which the absorptive section 74 is fabricated may typically be A inch thick. before being compressed normal to the face 75 to about 1/32 inch thickness represented by thickness 76. The absorptive section 74 is adhesively bonded to absorptive section 73 at the interface 77 by a hot melt adhesive as disclosed in the copending L&#39;.S. patent application Ser. No. 675.556. The same application also discloses and claims menstrual fluid absorptive section having a planar. dry. regenerated cellulose. fine pore sponge compressed normal to the planar dimension to minimize pore size openings.  
  A regenerated cellulose absorptive section 74 also is useful as a rapid and relatively large capacity menstrual fluid absorber. Section 74. like other primary absorptive sections. can primarily absorb menstrual fluid and allow the fluid. by capillary attraction, to flow to the larger area secondary absorptive section for storage purposes. It is desirable to have a planar area primary absorptive section proportioned in area to confront a vaginal vestibula. The quantity. weight/area. and number of tissue paper plies in a primary or a secondary absorptive section will be determined by the required volume of menstrual fluid to be absorbed under conditions of use of the menstrual sanitary napkin.  
  The obtuse diamond planar shapes of napkin l are particularly suited to manufacturing both primary and secondary absorptive sections simultaneously in multiple numbers. FIG. 8 illustrates the obtuse diamond planar shape pattern of a multiplicity of absorptive sections 80 adapted to be cut from a web of coplanarly confronting multiple tissue paper ply. The shape of the absorptive sections 80 and the napkin l are well adapted to conform to the required position for use on the female torso. Likewise. the absorptive sections 80 can be cut from a web. rapidly and efficiently. without substantial loss of web raw material. except for selvage 84 along the web edge. The obtuse diamond planar shape 80 as shown in the multiple pattern of FIG. 8 illustrates that a web 81 can be moved through a die cutting operation in the direction 82. The web 81 has a width 83. typically corresponding to 16 napkins being simultaneously die cut from a width 83 of 29% inch. or the like. allowing a small selvage loss.  
  FIG. 9 more specifically illustrates the geometrical requirement for the obtuse diamond planar shape of napkins l. 70. and web pattern shape 80. The planar shape 90 has the obtuse diamond geometry adapted to properly applying the pressure sensitive adhesive napkin securing means of the copending US. patent appli cation Ser. No. 675.556. in the proper geometrical position in a multiple fabrication operation. as in the web 81. The pressure sensitive adhesive strip 91 is coaxially located along the major axis 92 of the shape 90. The minor axis 93 bisects the obtuse flat length L of the diamond shape 90. The rectangular shaped tip 94 has a length /2 L and a tip width M. Thus. referring again to FIG. 8, the pattern of the web 81 can be constructed for a secondary absorptive section. allowing typical range for 92 of 6 to 9 inches. and for 93 of 1V2 to 3 inches. The L length typically ranges from /2 to 2 inches and width M typically ranges from /2 to 1 inch. The primary absorptive section. smaller in planar area in order to confront the vaginal vestibula. is similarly proportioned to the above secondary absorptive seetion dimensions. The primary absorptive section may be separately fabricated. using the adhesive plug bonding means of this invention. then securing the primary absorptive section to the secondary absoprtive section. as disclosed in the copening application U.S. Ser. No. 675.556.  
  in one embodiment of the invention. multiple equal width plies of tissue paper are combined by continously moving them together to form a web having multiple comt&#39;ronting planar plies. then simultaneously across the width of said web cutting through all of the plies to provide plural separate napkins. each having multiple nesting planar absorptive plies. disposed in sided-byside relationship while simultaneously forming in each of the napkins plural apertures each aperture having associated therewith a single flap or leaf-detent having .plural substantially coaxical confronting tissue layers and injecting a measured volume of hot melt adhesive into each of said plural apertures and cooling said adhesive in said apertures to provide plural adhesive pluglike bonds in each of said napkins. said adhesive being adapted to be tack free at human body temperature.  
  in a modification of the above embodiment a thin. flexible fluid impermeable membrane is disposed adjacent one face of an exterior ply of the multiple ply paper web before the cutting step and the membrane is bonded to the paper by the adhesive as it is injected and cooled in the apertures.  
  In another embodiment of the invention a first plural ply napkin is formed and disposed in co-extensive confronting relationship with a second plural ply napkin each napkin having been formed by the method or its modification described immediately above but for adhesive injecting and cooling steps. The apertures of both napkins are coincident. After the napkins are disposed one against the other in face-to-face relationship. a measured volume of hot-melt adhesive is injected in all apertures and cooled to bond all layers of the two napkins together with plural plug-like bonds of an adhesive selected to be tack-free at human body temperature.  
  in a modification of this last preceding embodiment. a thin. flexible fluid impermeable membrane is disposed in confronting planar relationship to an exterior ply of tissue of one of said webs prior to the cutting step and by the adhesive injecting and cooling steps the membrane is bonded to the exterior ply of tissue as are all plies in the stack to form an integral unit.  
  Many modifications and variations of my improvements in menstrual sanitary napkins and process for their manufacture may be made in light of my teachings. It is therefore understood that within the scope of the appended claims. the invention may be practiced otherwise than as specifically described.  
 What is claimed is:  
  l. A method for manufacturing menstrual napkins comprising: continuously combining moving equalwidth plies of tissue paper to form a web having multiple confronting planar plies, simultaneously across the width of said web cutting through all said plies in plural locations to form plural separate multiple-layer napkins in side-by side relationship while simultaneously forming. in each of said napkins. plural apertures. each of said aperatures having associated therewith a single leaf-detent having plural substantially coaxial confronting tissue layers and injecting a measure volume of a hot melt adhesive into each of said plural apertures and 7 cooling said adhesive in said apertures to provide plural adhesive plug bonds in each of said napkins. said adhesive being adapted to be tack free at human body ternperature.  
  2. The method of claim I including disposing a thin. flexible fluid impermeable membrane adjacent one face of an exterior ply of said web prior to said cutting step and bonding said membrane to said exterior ply by said injecting and cooling steps.  
  3. A process for making multiple ply tissue paper absorptive menstural napkins comprising: Combining continously multiple plies of thin tissue paper in confronting plural layers to form a first wide web. cutting simultaneously through all said multiple plies of said first web to provide multiple first napkins each having plural. nesting planar absorptive plies and forming in each of said first napkins two apertures each said aperture having associated therewith a single leaf detent of plural substantially coaxial layers. each of said first napkins having said two apertures disposed at opposite ends thereof; combining continuously additional multiple plies of thin paper sheets into confronting planar layers to form a second wide web simultaneously cutting through all plies of said second web to provide multiple second napkins having plural nesting planar absorptive plies and simultaneously forming in each of said second napkins two apertures each having associated therewith a single leaf-detent having plural substantially coxial confronting tissue layers; disposing at least one of said first napkins in confronting relationship with one of said second napkins with said apertures coinciding to provide a multiple napkin pair: simultaneously injecting of hot melt adhesive into each one of the afore said apertures of said napkin pair and cooling said adhesive in said apertures to provide plural solid plugs of adhesive. said adhesive being adapted to be tack free at human body temperature. said solid plugs of adhesive bonding said multiple ply napkin pairs together.  
  4. The method of claim 3 including disposing a thin. flexible fluid impermeable membrane in confronting planar relationship with an exterior ply of one said wide webs prior to said cutting steps. said injecting and cooling steps including bonding of said membrane to said exterior ply.