Patent Application
20190314213
This disclosure relates to absorbent tampons, and more specifically, relates to tampons with a high integrity absorbent member and processes for making such tampons.
Commercial catamenial tampons have been available for decades and there are many different designs known in the art. Most designs include, at a minimum, an absorbent member and a withdrawal member.
The highest incidence risks associated with the use of catamenial tampons are those related to tampons shedding fibers, breaking, or otherwise disintegrating inside of the user's vagina. This loss of integrity is often the result of weakness or inconsistency in the construction of the absorbent fiber web and, therefore, the absorbent member. The loss of integrity may results in hazards, such as, for example, mild harms such as inconvenience and pain and serious harm such as pelvic inflammatory disease, a dangerous infectious condition. Users who experience tampons coming apart inside them often require medical attention. One common method in the art for mitigating this user risk is to include a thin fluid permeable overwrap or veil around the absorbent member to help contain the fibers. While this overwrap can help reduce shedding and increase overall tampon integrity, they are known to fail, especially on radially wound tampons.
In addition to the safety risks, low integrity absorbent members also create inefficiencies, scrap, and product performance variation in the tampon manufacturing process. This results from the absorbent members breaking or “necking down,” which causes machine stops and creates weight variations and defects. Weight variations lead to variation in tampon absorbency, dimensions, and integrity, all of which negatively impact a manufacturer's ability to produce products in a cost effective manner.
There exists a need for absorbent members with improved integrity, particularly improved tensile strength, that can mitigate the risks of disintegrating tampons and that can improve conversion performance of manufacturing equipment. Ideally, such improved tampons are manufactured on manufacturing equipment that is easily modifiable and do not require significantly more absorbent fiber or greater dimensional configurations to attain desired absorbencies compared to current designs.
An object of the present invention is to provide catamenial tampons with improved absorbent member integrity and a method of manufacturing such tampons.
A tampon of this present invention can include configurations for all absorbencies defined by 21 CFR 801.430, including Light, Regular, Super, Super Plus, Ultra, and tampons with absorbency >18 g. A tampon according to an exemplary embodiment of the present invention is composed of an absorbent member comprising a mass of fibers entangled by needle punching having length direction and width direction tensile strengths of at least 10N when tested using the tensile method described herein. To form the absorbent member, a web of absorbent fibers is laid and entangled by needle punching at a needle punch density of at least 5 punches per cm2. To form the tampon, the absorbent member is cut to length and consolidated into an uncompressed “blank.” The blank is then compressed to form the tampon pledget. With this tampon configuration and construction method, a tampon is created that has greater fiber integrity and, therefore, greater user safety and machine processability as compared to conventional tampons.
The present invention is directed to an absorbent tampon composed of an absorbent member with improved integrity to prevent breakage, fiber loss, and otherwise disintegration, and a process for making the absorbent tampon. The present invention is not limited or restricted by the structures or particular configurations illustrated in the drawings.
As employed herein, the term “tampon” refers to any type of absorbent mass that is used in the vaginal cavity to absorb fluids such as menses. Tampons currently available in commerce are constructed of absorbent fibers known to be biocompatible, such as cotton and viscose rayon. Various tampon constructions are known, but most include the use of pads or strips of fiber mats (also known as fiber sliver, tape, or ribbon), termed “absorbent member” herein, that are compressed into a cylindrical or near-cylindrical shape. The compressed absorbent member along with any associated overwrap is termed “pledget” herein. It should be appreciated that in some contexts the terms tampon and pledget are interchangeable and that pledget can refer to both the pre-compressed and compressed forms. The term “tampon blank” is used herein to refer to the pre-compressed form.
In currently available tampons the absorbent member is created by forming webs of absorbent fibers that are entangled or bonded through chemical or mechanical means, and these absorbent members can be single or multilayer lamellar structures.
Several configurations of tampon blank construction from absorbent members are known, including simply compressing cut pads or further increasing fiber density before compression by rolling individual absorbent members or crisscrossing multiple absorbent members.
Tampons in accordance with the present invention are designed for insertion into the body by the user's finger, known as “digital” insertion, or with a tampon applicator. Tampon applicators are known, including those described in U.S. Pat. No. 4,921,474 to Suzuki and Masamitsu, the contents of which are incorporated herein by reference in their entirety.
The following test methods were used to demonstrate advantages of the present invention:
Tensile Strength
Sample preparation: To obtain the absorbent member, tampons were first unwrapped and removed from the applicator (if applicable). The overwrap, if present, was cut along the long axis of the tampon pledget. The absorbent member was then unrolled. To obtain standardized swatches for tensile pulls, two 30 mm×30 mm squares were cut from each absorbent member. Care was taken to ensure the square sides were approximately parallel to the length and width edges of the absorbent member.
Sample swatches were tested in an Instron pull force tester. To test, samples were clamped into 1 inch by 1 inch sets of square pneumatic jaws. The bottom set of jaws remained stationary and the top set of jaws was attached to a 500 N force cell. Prior to clamping the samples into the jaws, the top jaws were situated 15 mm from the bottom jaws. Once clamped in length-pull or width-pull orientations, samples were pulled vertically at a rate of 300 mm/min for 60 mm. Maximum load in Newtons (N) as defined as the peak of the stress/strain curve was recorded. Instron Bluehill software was used for recording and marking pull force data. Samples were tested in a climate controlled lab at room temperature.
The following Examples and Comparative Examples illustrate advantages of the present invention:
A 144 gsm pad with dimensions of 150 mm×45 mm and an absorbency in the regular absorbency range was prepared using 100% viscose rayon fiber and needle punching at a punch density of 60 punches/cm2.
A 191 gsm pad with dimensions of 150 mm×50 mm and an absorbency in the super absorbency range was prepared using 100% viscose rayon fiber and needle punching at a punch density of 60 punches/cm2.
A 244 gsm pad with dimensions of 150 mm×50 mm and an absorbency in the plus absorbency range was prepared using 100% viscose rayon fiber and needle punching at a punch density of 60 punches/cm2.
Comparative Example A: Store brand; 100% cotton radially wound tampon without overwrap; tampon is in an applicator tube.
Comparative Example B: U by K® Click®; 100% rayon radially wound tampon with overwrap; tampon is in an applicator tube.
Comparative Example C: o.b.; 100% rayon radially wound tampon with overwrap; packaged for digital insertion.
Absorbent members from Examples 1-3 and the Comparative Examples A-C were subjected to the tensile test method described above, and the results are shown in Table 1. Ten tensile strength measurements were taken from representative absorbent members, five in the length direction and five in the width direction. As shown in Table 1, in the on-market tampons, the absorbent member was considerably weaker in at least one of the two directions tested. Table 1 shows the lowest tensile strength of the two obtained measurements (length and width) for each of the absorbent members and demonstrates that the lowest tensile strength of the inventive absorbent member is substantially higher than that of all comparative tampons tested.
The construction methods of the conventional tampon absorbent members cause the distribution of the tampon absorbent member's strength to be disproportionate between length and width directions. Ideally, a tampon absorbent member would be strong in both directions and the overall relationship between length and width tensile strengths would be similar. Processes in accordance with the present invention create a tampon absorbent member with substantially better relationship between tensile strength directions as compared to absorbent members formed using conventional processes. In this regard, Table 2 shows the average ratio of the maximum and minimum tensile directions for each absorbent member type, and specifically shows that Examples 1-3 have average ratios between unity and ≤2.00, while all Comparative Examples are greater than this.
While in the foregoing specification a detailed description of specific embodiments of the invention was set forth, it will be understood that many of the details herein given may be varied considerably by those skilled in the art without departing from the spirit and scope of the invention.
This application claims the benefit of U.S. Provisional Patent Application No. 62/658,700 filed Apr. 17, 2018, the contents of which are herein incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62658700 | Apr 2018 | US |
