Fluid management layer for absorbent articles
阅读说明：本技术 用于吸收制品的流体管理层 (Fluid management layer for absorbent articles ) 是由 G.A.维恩斯 C.D.纳兰乔马丁 P.D.梅洛 于 2020-03-27 设计创作，主要内容包括：本发明描述了一种具有整合的粗梳非织造物的流体管理层。该流体管理层具有约40克/平方米(gsm)至约75gsm的基重；多根吸收纤维、多根加强纤维和多根弹性纤维；其中该流体管理层表现出大于0.40mm的总压缩并且具有至少0.35mm的总恢复,并且其中该流体管理层具有小于或等于0.08g/cc的密度。(A fluid management layer with an integrated carded nonwoven is described. The fluid management layer has a basis weight of about 40 grams per square meter (gsm) to about 75 gsm; a plurality of absorbent fibers, a plurality of reinforcing fibers, and a plurality of elastic fibers; wherein the fluid management layer exhibits a total compression of greater than 0.40mm and has a total recovery of at least 0.35mm, and wherein the fluid management layer has a density of less than or equal to 0.08 g/cc.)
1. A fluid management layer comprising an integrated carded nonwoven having a basis weight of about 40 grams per square meter (gsm) to about 75gsm, the fluid management layer comprising a plurality of absorbent fibers, a plurality of reinforcing fibers, and a plurality of elastic fibers, as determined by material composition analysis; wherein the fluid management layer exhibits a total compression of greater than 0.40mm and has a total recovery of at least 0.35mm as determined by the compressed thickness method; and wherein the fluid management layer has a density of less than or equal to 0.08g/cc as determined by the density method.
2. The fluid management layer of claim 1 wherein the fluid management layer exhibits a total compression of from about 0.40mm to about 0.70mm, more preferably from about 0.41mm to about 0.70mm, most preferably from about 0.43mm to 0.70 mm.
3. The fluid management layer of any preceding claim wherein the fluid management layer has an overall recovery of from about 0.35mm to about 0.70mm, more preferably from about 0.36mm to about 0.70mm, and most preferably from about 0.37mm to about 0.70 mm.
4. The fluid management layer according to any preceding claim wherein the fluid management layer has a basis weight of from 45gsm to about 60gsm, and most preferably from about 50gsm to about 55gsm, as determined by the basis weight method.
5. The fluid management layer of any preceding claim wherein the fluid management layer exhibits a reduction in thickness of at least about 0.13mm, more preferably at least about 0.15mm, most preferably at least about 0.17mm, as a final thickness measured from 0.5kPa to 1 kPa.
6. The fluid management layer of claim 5 wherein the fluid management layer exhibits a reduction in thickness of from about 0.13mm to about 0.30mm, more preferably from about 0.15mm to about 0.30mm, most preferably from about 0.17mm to about 0.30mm, as a final thickness measured from 0.5kPa to 1 kPa.
7. The fluid management layer of any preceding claim wherein the fluid management layer exhibits a reduction in thickness of at least about 0.20mm, more preferably at least about 0.25mm, most preferably at least about 0.30mm, as a final thickness measured from 0.5kPa to 2 kPa.
8. The fluid management layer of any preceding claim wherein the fluid management layer exhibits a reduction in thickness of from about 0.20mm to about 0.50mm, more preferably from about 0.21mm to about 0.50mm, and most preferably from about 0.25mm to about 0.50mm, as a final thickness measured from 0.5kPa to 2 kPa.
9. The fluid management layer of any preceding claim wherein the fluid management layer exhibits a reduction in thickness of at least about 0.25mm, more preferably at least about 0.30mm, most preferably at least about 0.35mm, as a final thickness measured from 0.5kPa to 3 kPa.
10. The fluid management layer of claim 9 wherein the fluid management layer exhibits a reduction in thickness of from about 0.25mm to about 0.60mm, more preferably from about 0.30mm to about 0.60mm, or most preferably from about 0.35mm to about 0.60mm, as a final thickness measured from 0.5kPa to 3 kPa.
11. The fluid management layer of any preceding claim wherein the fluid management layer has a basis weight of from about 50gsm to about 60gsm, and wherein the nonwoven has a density of from 0.020g/cc to 0.080g/cc, more preferably from 0.030g/cc to 0.070g/cc, or most preferably from 0.035g/cc to 0.065 g/cc.
12. The fluid management layer of claim 11, wherein the fluid management layer has an air permeability of from about 200m ^3/m ^2/min to about 400m ^3/m ^2/min, more preferably from about 250m ^3/m ^2/min to about 375m ^3/m ^2/min, or most preferably from about 300m ^3/m ^2/min to about 370m ^3/m ^2/min, as measured by the air permeability method.
13. A disposable absorbent article comprising a topsheet, a backsheet, an absorbent core disposed between the topsheet and the backsheet, and a fluid management layer according to any of the preceding claims disposed between the topsheet and the backsheet.
14. The disposable absorbent article of claim 13, wherein the fluid management layer is disposed between the absorbent core and the topsheet.
15. The disposable absorbent article of claim 14, wherein the disposable absorbent article exhibits a stain size of less than 50cm ^2, less than 47cm ^2, or most preferably less than 40cm ^2 as measured by the stain size measurement method.
16. The disposable absorbent article of any of claims 14 and 15, wherein the absorbent article of the present disclosure can exhibit the stain size of from about 30cm ^2 to about 50cm ^2, more preferably from about 30cm ^2 to about 46cm ^2, or most preferably from about 30cm ^2 to about 42cm ^ 2.
Technical Field
The present disclosure relates generally to fluid management layers for disposable absorbent articles, and in particular to fluid management layers that are carded staple fiber nonwovens having improved performance characteristics.
Background
Disposable absorbent articles such as feminine hygiene articles, taped diapers, pant diapers, and incontinence articles are designed to absorb fluid from the body of the wearer. Users of such disposable absorbent articles have several concerns. For example, leakage from products such as catamenial pads, diapers, sanitary napkins, and incontinence pads is an important concern. In addition, the comfort of the product and the feel of fitting to the wearer's body are also an area of concern. To provide better comfort, current disposable absorbent articles are typically provided with a topsheet that is flexible, soft-feeling, and non-irritating to the wearer's skin. The topsheet itself does not contain the discharged fluid. Rather, the topsheet is fluid permeable to allow fluid to flow into the absorbent core.
With respect to comfort, some consumers may desire a product having sufficient thickness and rigidity to provide a desired amount of protection while also being flexible. Lofty materials may be used to provide a thick cushion feel (cushiony welting) article. However, in use, these lofty materials may experience various compressive loads. Recovery from these compressive loads is critical in maintaining the cushion feel of the article. Exacerbating this problem is the fact that once fluid is introduced into the absorbent article, the material properties of the article change. Thus, an article that can meet the necessary criteria of a consumer before use may no longer be comfortable, flexible, or have a desired stiffness for the user after the absorbent article has absorbed a given amount of fluid.
Thus, there is a need to create a fluid management material with sufficient thickness and compression recovery for use in absorbent articles.
Disclosure of Invention
Absorbent articles of the present disclosure include a topsheet, a backsheet, and an absorbent core disposed between the topsheet and the backsheet. The fluid management layer is disposed between the topsheet and the absorbent core. The fluid management layer includes a carded staple fiber nonwoven material comprising a plurality of fibers.
The fluid management layer of the present disclosure has a basis weight of about 40 grams per square meter (gsm) to about 75gsm, the fluid management layer comprising a plurality of absorbent fibers, a plurality of reinforcing fibers, and a plurality of elastic fibers, wherein the fluid management layer exhibits a total compression of greater than 0.40mm and has a total recovery of at least 0.35mm, and wherein the fluid management layer has a density of less than or equal to 0.08 g/cc.
In another implementation, the fluid management layer of the present disclosure includes a plurality of absorbent fibers, a plurality of reinforcing fibers, and a plurality of elastic fibers. The fluid management layer may have a ratio of absorbent fibers to reinforcing fibers in weight percent of the fluid management layer of the present disclosure of less than 1:1, more preferably less than 0.6:1, most preferably less than 0.5:1, specifically including all values within these ranges and any ranges formed thereby. Similarly, the ratio of absorbent fibers to elastic fibers in the fluid management layers of the present disclosure is less than 1:1, more preferably less than 0.8:1, or most preferably less than 0.7:1, by weight percent, specifically including all values within these ranges and any ranges formed therefrom.
Drawings
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as the present invention, it is believed that the invention will be more fully understood from the following description taken in conjunction with the accompanying drawings. Some of these figures may have been simplified by the omission of selected elements in order to more clearly show other elements. Such omissions of elements in certain figures do not necessarily indicate the presence or absence of particular elements in any of the exemplary embodiments, unless explicitly stated to the contrary in the corresponding written description. The figures are not drawn to scale.
FIG. 1A is a schematic view of a disposable absorbent article constructed according to the present disclosure;
FIG. 1B is a schematic view of an absorbent system of the disposable absorbent article shown in FIG. 1A;
FIG. 2 is a schematic view of a process that may be used to construct the fluid management layers of the present disclosure;
FIG. 3 is a schematic illustration of a front view of a fluid management layer constructed according to the present disclosure; and is
Fig. 4-6B are schematic diagrams illustrating an apparatus for performing the repeat acquisition time and rewet test method.
Detailed Description
As used herein, the following terms shall have the meanings specified below:
"absorbent article" refers to a wearable device that absorbs and contains liquid, and more specifically, refers to a device that is placed against or in proximity to the body of the wearer to absorb and contain the various exudates discharged from the body. Absorbent articles may include diapers, training pants, adult incontinence undergarments (e.g., liners, pads, and briefs), and/or feminine hygiene articles.
A "longitudinal" direction is a direction extending parallel to the maximum linear dimension (typically the longitudinal axis) of the article and includes directions within 45 ° of the longitudinal direction. As used herein, "length" of an article or component thereof generally refers to the size/distance of the largest linear dimension, or generally the size/distance of the longitudinal axis of the article or component thereof.
The "lateral" or "transverse" direction is orthogonal to the longitudinal direction, i.e. in the same major plane of the article and the longitudinal axis, and the transverse direction is parallel to the transverse axis. As used herein, the "width" of an article or a component thereof refers to the size/distance of the dimension orthogonal to the longitudinal direction of the article or a component thereof, i.e. orthogonal to the length of the article or a component thereof, and typically it refers to the distance/size of the dimension parallel to the transverse axis of the article or component.
The "Z-direction" is orthogonal to both the longitudinal and transverse directions.
As used herein, "machine direction" or "MD" refers to the direction parallel to the flow of carded staple fiber nonwoven through a nonwoven preparation machine and/or absorbent article product manufacturing equipment.
As used herein, "cross direction" or "CD" refers to a direction parallel to the width of the carded staple fiber nonwoven production machine and/or absorbent article product manufacturing equipment and perpendicular to the machine direction.
As used herein, the term "integrated" is used to describe fibers of a nonwoven material that have been interwoven, entangled, and/or pushed/pulled in the positive and/or negative Z-direction (the thickness direction of the nonwoven material). Some exemplary processes for integrating the fibers of a nonwoven web include hydroentangling and needling. Hydroentangling uses a plurality of high pressure water jets to entangle the fibers. Needling involves the use of needles to push and/or pull the fibers to entangle them with other fibers in the nonwoven. Also this type of integration does not require an adhesive or binder to hold the fibers of the fluid management layer together.
As used herein, the term "carded" is used to describe structural features of the fluid management layers described herein. Carded nonwovens utilize fibers that are cut to specific lengths, otherwise known as "short length fibers". The short length fibers may be of any suitable length. For example, short length fibers may have a length of up to 120mm or may have a length as short as 10 mm. However, if the particular set of fibers are short length fibers (e.g., viscose fibers), the length of each of the viscose fibers in the carded nonwoven is predominantly the same, i.e., short length. It is noted that where additional staple length fiber types are included, such as polypropylene fibers, the length of each of the polypropylene fibers in the carded nonwoven is also predominantly the same. However, the short length of the viscose fibres and the short length of the polypropylene fibres may be different.
In contrast, continuous filaments, such as by a spunbond process or a meltblown process, do not produce short length fibers. Rather, these filaments have indeterminate lengths and are not cut to specific lengths as described with respect to their staple length counterparts.
Carded integrated nonwovens as disclosed herein can be used in a variety of disposable absorbent articles, but are particularly useful in diapers, feminine hygiene articles, and incontinence articles such as sanitary napkins and incontinence pads. The integrated carded nonwovens of the present disclosure may be particularly useful as fluid management layers in the absorbent articles described above. In addition, the carded integrated nonwovens of the present disclosure provide increased caliper (even at lower basis weights), have good compression recovery properties, and can provide stain masking benefits.
Fig. 1A shows a schematic cross-section of an exemplary absorbent article. As shown, an absorbent article 10 according to the present disclosure includes a topsheet 20, a backsheet 50, and an absorbent core 40 disposed between the topsheet 20 and the backsheet 50. The fluid management layer 30 is disposed between the topsheet 20 and the absorbent core 40. The absorbent article has a wearer-facing surface 60 and an opposite garment-facing surface 62. The wearer-facing surface 60 may comprise the topsheet 20 and the garment-facing surface 62 may comprise the backsheet 50. Additional components may be included in the wearer-facing surface 60 and/or the garment-facing surface 62. For example, if the absorbent article is an incontinence pad, a pair of barrier cuffs extending generally parallel to the longitudinal axis L of the absorbent article 10 may also form a portion of the wearer-facing surface 60. Similarly, a fastening adhesive may be present on the backsheet 50 and form a portion of the garment-facing surface 62 of the absorbent article.
Referring now to fig. 1A and 1B, the fluid management layer 30 includes opposing end edges 32A and 32B that may extend generally parallel to the transverse axis T. Moreover, the fluid management layer 30 includes side edges 31A and 32B that may extend substantially parallel to the longitudinal axis L. Similarly, the absorbent core 40 includes opposing end edges 42A and 42B that may extend generally parallel to the transverse axis T. Moreover, the absorbent core 40 may comprise side edges 41A and 41B extending substantially parallel to the longitudinal axis L.
As shown, each of the end edges 32A and 32B of the fluid management layer 30 may be disposed longitudinally outboard of the absorbent core 40. However, this is not necessarily required. For example, the end edges 32A and/or 32B may be coextensive with the absorbent core 40, or the end edges 32A and/or 32B may be disposed longitudinally inboard of the end edges 42A and/or 42B of the absorbent core 40.
Similarly, the side edges 31A and/or 31B may be disposed laterally outward of the side edges 41A and 41B of the absorbent core 40. Alternatively, the side edges 31A and/or 31B may be coextensive with the side edges 41A and/or 41B of the absorbent core 40.
As previously mentioned, the fluid management layer of the present disclosure is an integrated carded nonwoven material. Various configurations of the fluid management layer can be achieved. However, it is important that the fluid management layer of the present disclosure be sufficiently open to allow rapid fluid collection, but also be able to lock in liquid invaders to reduce the likelihood of rewet. The fluid management layer of the present disclosure can comprise a plurality of carded webs. Accordingly, the carded webs that make up the fluid management layer can be different from one another. For example, one of the carded webs may comprise a different blend of fibers than the other carded webs. In particular, given that the first carded web will be closest to the wearer-facing surface in the absorbent article, the selection of fibers for the first carded web may be such that there is a greater degree of openness associated with that web. The second carded web may take a similar configuration. In contrast, the third carded web can be configured to collect liquid insults from the void spaces of the first and second carded webs and to effectively distribute these liquid insults to the absorbent core (heterogeneous configuration). Alternatively, the first, second, and third carded webs can be constructed the same, e.g., having the same blend of fibers (homogeneous configuration).
A schematic of an exemplary carding and integration process suitable for producing the fluid management layer 30 of the present disclosure is provided in fig. 2. As shown, a plurality of carders 210, 220, and 230 may each produce a carded nonwoven web that is transferred to a conveyor belt 240, such as 214, 224, and 234, respectively. Each of the carded nonwoven webs 214, 224, and 234 can be provided to a conveyor belt 240 via web chutes 212, 222, 232, respectively. It is also worth noting that after the carded nonwoven 214 is deposited on the conveyor belt 240, the carded nonwoven 224 is then deposited on the first carded nonwoven 214 on the conveyor belt 240. Similarly, a third carded nonwoven web 234 is deposited on the second carded nonwoven 224 and the first carded nonwoven 214 on the conveyor belt 240. Subsequently, each of the first, second, and third carded nonwoven webs 214, 224, 234 are then provided to an integration process 250 that utilizes needles and/or high pressure water streams to entangle the fibers of the first, second, and third carded nonwoven webs. Both carding and integration processes are well known in the art. As noted above, the fluid management layer of the present disclosure includes one or more carded webs. In the case where the fluid management layer comprises two carded webs, the need for a third carding machine can be eliminated. An additional card can be utilized. The resulting structure will be a nonwoven web having four strata.
It is noteworthy that the fluid management layers of the present disclosure (especially those that are layered like) may require only one card. However, such an operation may be inefficient because one card would be required to deposit the desired basis weight of fibers.
Once these carded webs are integrated, they cannot be separated manually-at least without significant effort and time. Each carded nonwoven web forms a stratified layer throughout the fluid management layer. Each of the stratified layers may retain the unique characteristics of at least a portion of the stratified layer in the z-direction, even when integrated into a larger fluid management layer. The fluid management layer provides capillary suction to "pull" fluid through the topsheet, an operation that is opposed by trickle/low flow conditions. The fluid management layer may also contain gushes of fluid by providing a distribution function to efficiently utilize the absorbent core and provide intermediate storage until the absorbent core can accept the fluid.
Referring now to FIG. 3, typical thicknesses on a hydroentangling line may range from about 0.03mm/10gsm to about 0.12mm/10 gsm. In a conventional hydroentangling line, the web is hit by a plurality of water jets on the first surface 300A and the second surface 300B. Additionally, the web is typically wound around various rolls such that additional water jets may further entangle the layered constituent fibers. Additionally, these webs may be wound around a roll dryer. However, the inventors have found that the winding of the web around these rolls results in compression on the web and actually reduces the thickness of the web. By reducing the number of rolls on which the web is wound during processing, the inventors have been able to increase the thickness of the integrated web, which in turn equates to a higher thickness on the fluid management layer of the present disclosure.
Thus, unlike conventional hydroentangled materials, the fluid management layers of the present disclosure can have a caliper factor (mm thickness/10 gsm) of at least about 0.13mm, at least about 0.15mm, or about 0.2mm, including any value within these ranges and any ranges formed thereby. The fluid management layer 30 may have a thickness coefficient of 0.13mm to about 0.3mm, or about 0.14mm to about 0.25mm, or about 0.15mm to about 0.22mm, including any value within these ranges and any range formed thereby. Thickness data for various samples are provided below.
Notably, conventional hydroentangling lines are typically capable of handling basis weights of up to about 110gsm of material. This limitation is due in part to the capacity of the card. There have been experiments in the past by one or more of the inventors in which the basis weight on a conventional hydroentangling line exceeded 130gsm, reaching 0.24mm per 10gsm of thickness; however, these experiments were performed using multiple passes under a carding machine. Basically, the web from the card is consolidated and is rewound and consolidated again under the card. Thus, it is believed that the thickness effect is due in large part to the spacing between the first channel and the second channel.
In addition, the thickness coefficient is derived from thickness data of the material wound for storage/transportation. A thickness measurement pre-winding can be performed which will result in a much higher thickness factor. However, such thickness measurements may not necessarily reflect the fluid management layer that makes it an article.
The inventors have also found that this processing technique can be used not only for hydroentangled materials in which the layering is heterogeneous, but also for hydroentangled materials in which the layering is homogenous (e.g., each layering has the same fiber composition). In addition, the inventors have surprisingly found that hydroentangled materials constructed using this method can also provide good elasticity and compression recovery over those produced by conventional production lines. In addition, with proper fiber selection, the inventors have also found that good compression recovery can be obtained in addition to increased caliper. Fiber selection and compression recovery data for various samples are also provided below.
The fluid management layer of the present disclosure may have a basis weight of up to 75 grams per square meter (gsm) compared to the 130gsm experiment mentioned previously; or a basis weight of at most 70 gsm; or a basis weight in the range of about 40gsm to about 75 gsm; or a basis weight in the range of about 50gsm to about 70 gsm; or a basis weight in the range of about 55gsm to about 65gsm, including any value within these ranges and any range formed thereby. In another particular example, the fluid management layer 30 may have a basis weight of 40gsm to 60 gsm.
Some absorbent articles may not require as much basis weight as described above. For example, liners that do not typically have the same level of absorbent capacity as sanitary napkins may be able to have a basis weight that is reduced over the basis weight described above. For example, the fluid management layer may have a basis weight of from 30gsm to 70gsm, or more preferably from 35gsm to about 65gsm, or most preferably from about 40gsm to about 60gsm, specifically including all values within these ranges and any ranges formed therefrom. In one particular example, the fluid management layer of the present disclosure may have a basis weight of about 55 gsm.
Still referring to fig. 1A-3, due to fiber integration, fluid management layer 30 does not require an adhesive or latex adhesive to achieve stability. Additionally, the carded staple fiber nonwoven of the fluid management layer of the present disclosure can be made from a wide variety of suitable fiber types that yield the desired performance characteristics, which will be discussed in further detail below.
As will be discussed in further detail below, the types of fibers in the fluid management layers of the present disclosure are described in terms of their function within the fluid management layer. For example, absorbent fibers are used to absorb liquid insults. The reinforcing fibers are used to bond together by heat treatment to provide stiffness to the fluid management layer. The elastic fibers are used to provide recovery from compressive forces acting on the fluid management layer.
To enhance the stabilizing effect of the integration, crimped fibers may be utilized. As discussed in more detail below, the fluid management layers of the present disclosure may include absorbent fibers, reinforcing fibers, and elastic fibers. One or more of these fibers may be crimped prior to integration. For example, where synthetic fibers are utilized, the fibers may be mechanically crimped via intermeshing teeth. Also for absorbent fibers, these fibers may be mechanically crimped and/or may have chemically induced crimps due to the variable skin thickness formed during the production of the absorbent fiber.
In general, the fluid management layers of the present disclosure may include absorbent fibers within the following ranges: from about 15% to about 60%, from about 20% to about 50%, from about 25% to about 40%, by weight, specifically including any value within these ranges and any range formed thereby. In one particular example, the fluid management layer may include about 30% by weight absorbent fibers.
Similarly, in general, the fluid management layers of the present disclosure may include elastic fibers within the following ranges: from about 20% to about 70%, from about 30% to about 60%, from about 35% to about 50%, specifically including all values within these ranges and any ranges formed therefrom. In one particular example, the fluid management layer may include about 40% by weight of the elastic fibers.
Moreover, the fluid management layer of the present disclosure may include reinforcing fibers within the following ranges: from about 15 wt% to about 60 wt%, from about 20 wt% to about 50 wt%, or from about 25 wt% to about 40 wt%, specifically including all values within these ranges and any ranges formed therefrom. In one particular example, the fluid management layer 30 may include about 30 wt% reinforcing fibers.
For the fluid management layers of the present disclosure, the weight percent of reinforcing fibers may be greater than or equal to the weight percent of elastic fibers. The weight percentage of the absorbent fibers may be less than the weight percentage of the elastic fibers and/or the reinforcing fibers. Generally, a higher weight percentage of absorbent fibers is believed to be beneficial for rapid absorption of fluid insults; however, this facilitates the absorbent core dewatering of the absorbent fibers, considering that the absorbent fibers are close to the topsheet. Where a greater percentage of absorbent fibers are present, a larger core is typically required to dewater the absorbent fibers. This usually results in higher costs. Accordingly, the ratio of absorbent fibers to reinforcing fibers in weight percent in the fluid management layers of the present disclosure is less than 1:1, more preferably less than 0.6:1, and most preferably less than 0.5:1, specifically including all values within these ranges and any ranges formed therefrom. Similarly, the ratio of absorbent fibers to elastic fibers in the fluid management layers of the present disclosure is less than 1:1, more preferably less than 0.8:1, or most preferably less than 0.7:1, by weight percent, specifically including all values within these ranges and any ranges formed therefrom.
Whether the fluid management layer is used in an adult incontinence article or a catamenial article, it is crucial that the fluid management layer acquires the liquid insult from the topsheet and pulls the liquid away from the topsheet far enough so that the ability of the topsheet to be wet is not felt. To achieve this, the inventors have found that the increased thickness described herein can facilitate fluid acquisition due to the increased void volume of the fluid management layer. A higher thickness at a lower basis weight equates to a greater void volume, which can facilitate fluid acquisition. However, it is important to balance thickness and capillary action. Thus, while increased thickness may provide a pad-like fluid management layer, the fluid management layer is not very effective from a fluid handling perspective if there is no proper wicking fiber selection (especially in a menses environment).
In addition, the increased thickness of the fluid management layer may also provide stain masking benefits. That is, stains visible through topsheets of absorbent articles using the fluid management layers of the present disclosure appear much smaller, and much less red, than their conventional fluid management layer counterparts. Stain size data is provided below.
Returning to the discussion of void volume, for a set basis weight of a fiber, a larger diameter fiber may provide a greater void volume between adjacent fibers than its smaller diameter counterpart. Thus, it may also be important that the fiber size of the fibers in the layering be close to the topsheet. That is, if the diameter of the excess fibers in the first and/or second carded nonwovens is too small, this can adversely affect the permeability and void volume created for rapid fluid acquisition (assuming the first and second carded nonwovens are closer to the topsheet than the third carded nonwoven).
Ideally, the fluid management layer can have sufficient capillarity to drain the topsheet, particularly in a menses environment. Capillary action is driven by the pores; however, too small an aperture will reduce the permeability, which will also negatively affect the acquisition rate and lead to a wet feel of the topsheet.
Accordingly, the inventors have carefully selected not only the fiber type in each of the stratified layers in the fluid management layers of the present disclosure, but also the diameter of the fiber type. The type of fibers of each layer is discussed in more detail below. Notably, the following discussion regarding the types of fibers in the layers of the fluid management layer assumes that the first carded nonwoven web is closer to the topsheet than the second carded nonwoven web and/or the third carded nonwoven web.
Any suitable linear density of absorbent fibers may be utilized. For example, the absorbent fiber linear density can be in a range of from about 1 dtex to about 7 dtex, from about 1.4 dtex to about 6 dtex, or from about 1.7 dtex to about 5 dtex, specifically including all values within these ranges and any ranges formed therefrom. In one particular example, the absorbent fibers may include a linear density of about 1.7 dtex.
The absorbent fibers of the fluid management layers of the present disclosure can have any suitable shape. Some examples include trilobal, "H" -shaped, "Y" -shaped, "X" -shaped, "T" -shaped, or circular. Further, the absorbent fibers may be solid, hollow, or multi-hollow. Other examples of multi-lobal absorbent fibers suitable for use in the carded staple fiber nonwovens detailed herein are disclosed in the following patents: U.S. patent 6,333,108 to Wilkes et al, U.S. patent 5,634,914 to Wilkes et al, and U.S. patent 5,458,835 to Wilkes et al. The trilobal shape improves wicking and improves masking. Suitable trilobal rayon fibers are available from Kelheim fibers and are sold under the trade name Galaxy. Although each layer may comprise different shapes of absorbent fibers (much like described above), not all carding equipment may be adapted to handle such variations between two/more layers. In one particular example, the fluid management layer comprises circular absorbent fibers.
Any suitable absorbent fiber may be utilized. Some conventional absorbent fibers include cotton, rayon, or regenerated cellulose, or combinations thereof. In one example, the fluid management layer may comprise viscose cellulose fibers. The absorbent fibers may comprise short length fibers. The staple length of the absorbent fibers can range from about 20mm to about 100mm, or from about 30mm to about 50mm, or from about 35mm to about 45mm, specifically including all values within these ranges and any ranges formed therefrom.
As previously mentioned, the fluid management layer may also include reinforcing fibers in addition to the absorbent fibers. Reinforcing fibers may be utilized to help provide structural integrity to the fluid management layer. The reinforcing fibers can help improve the structural integrity of the fluid management layer in the machine direction and cross direction, which facilitates web handling during handling of the fluid management layer for incorporation into a disposable absorbent article. In this regard, the constituent materials of the rigid fibers, the weight percentages of the rigid fibers, and the heating process should be carefully selected. The thermal hardening process is discussed below.
Any suitable linear density of reinforcing fibers may be utilized. For example, the reinforcing fiber linear density may be in a range of about 1.7 dtex to about 12 dtex, about 4 dtex to about 10 dtex, or about 5 dtex to about 7 dtex, specifically including all values within these ranges and any ranges formed thereby. In one particular example, the reinforcing fibers may include a linear density of about 5.8 dtex.
Any suitable reinforcing fiber may be utilized. Some examples of suitable rigid fibers include bicomponent fibers comprising polyethylene and polyethylene terephthalate components or polyethylene terephthalate and co-polyethylene terephthalate components. The components of the bicomponent fiber can be arranged in a sheath-core configuration, a side-by-side configuration, an eccentric sheath-core configuration, a trilobal configuration, and the like. In one particular example, the rigid fibers may comprise bicomponent fibers arranged in a concentric core-sheath configuration having a polyethylene/polyethylene terephthalate component, wherein the polyethylene is the sheath.
Although other materials may be used to form the elastic structure, the inventors have found that the stiffness of the polyethylene terephthalate is necessary to form the elastic structure. In contrast, the polyethylene component of the reinforcing fibers may be used to bond to each other during heat treatment. This can help provide tensile strength to the web in both the MD and CD. Furthermore, the bonding of the polyethylene component to the other polyethylene components of the reinforcing fibers may also create anchor points in the nonwoven. These fixation points can reduce the amount of fiber-to-fiber slippage, thereby increasing the elasticity of the material.
One of the benefits of reinforcing fibers is that the integrated nonwoven can be heat treated after fiber entanglement. The heat treatment may provide additional structural integrity to the integrated nonwoven by forming bonds between adjacent reinforcing fibers. Thus, with a higher percentage of rigid fibers present, more connection points may be formed. However, too many connection points may create a much stiffer fluid management layer, which may adversely affect comfort. Thus, the weight percentage of the reinforcing fibers may be important when designing the absorbent article.
With respect to the thermal hardening process, any suitable temperature may be utilized. Moreover, the appropriate temperature may be influenced in part by the constituent chemicals of the reinforcing fibers and by the treatment of the fluid management layer web. The fluid management layer web may be thermally cured at 132 degrees celsius. It should also be noted that in order to provide uniform stiffness properties throughout the fluid management layer, any heating operation should be arranged to provide uniform heating to the fluid management layer web. Even small temperature changes can greatly affect the tensile strength of the fluid management layer.
As previously mentioned, the fluid management layers of the present disclosure may additionally include elastic fibers. The elastic fibers can help the fluid management layer maintain its permeability and compression recovery. Any size suitable fiber may be utilized. For example, the elastic fibers may have a linear density in the following range: from about 1 dtex to about 12 dtex, from about 2 dtex to about 7 dtex, or from about 3 dtex to about 5 dtex, specifically including all values within these ranges and any ranges formed therefrom. In one particular example, the elastic fibers may include a linear density of about 4.4 dtex. In another specific example, the fluid management layer may include elastic fibers having variable cross-sections, such as circular and hollow spirals, and/or may include elastic fibers having variable decitex.
The elastic fibers may be any suitable thermoplastic fibers such as polypropylene (PP), polyethylene terephthalate, or other suitable thermoplastic fibers known in the art. Staple fiber lengths of the elastic fibers may range from about 20mm to about 100mm, or from about 30mm to about 50mm, or from about 35mm to about 45 mm. The thermoplastic fibers can have any suitable structure or shape. For example, the thermoplastic fibers may be round or have other shapes, such as a spiral, a notched oval, a trilobal, a notched ribbon, and the like. Further, the PP fibers may be solid, hollow, or multi-hollow. The elastic fibers may be solid and round in shape. Other suitable examples of elastic fibers include polyester/co-extruded polyester fibers. In addition, other suitable examples of elastic fibers include bicomponent fibers such as polyethylene/polypropylene, polyethylene/polyethylene terephthalate, polypropylene/polyethylene terephthalate. These bicomponent fibers can be configured as a sheath and a core. Bicomponent fibers can provide a cost effective way to increase the basis weight of the material while also optimizing the pore size distribution.
The elastic fibers may be polyethylene terephthalate (PET) fibers or other suitable non-cellulosic fibers known in the art. The PET fibers may have any suitable structure or shape. For example, the PET fibers may be round or have other shapes, such as helical, notched elliptical, trilobal, notched ribbon, hollow helical, and the like. Furthermore, the PET fibers may be solid, hollow, or multi-hollow. In one particular example, the fibers may be fibers made of hollow/spiral PET. Optionally, the elastic fibers may be spiral-pleated or flat-pleated. The elastic fibers can have a crimp value of about 4 to about 12 crimps per inch (cpi), or about 4 to about 8cpi, or about 5 to about 7cpi, or about 9 to about 10 cpi. Specific non-limiting examples of elastic fibers are available from Wellman, inc., Ireland under the trade names H1311 and T5974. Other examples of elastic fibers suitable for use in the carded staple fiber nonwovens detailed herein are disclosed in U.S. patent 7,767,598 to Schneider et al.
Notably, the reinforcing fibers and elastic fibers should be carefully selected. For example, while the constituent chemistries of the reinforcing fibers and elastic fibers may be similar, the elastic fibers should be selected such that the melting temperature of their constituent materials is higher than the melting temperature of the reinforcing fibers. Otherwise, during heat treatment, the elastic fibers will bond to the reinforcing fibers and vice versa, and an excessively stiff structure may be formed. It is noted that where the reinforcing fibers comprise bicomponent fibers (i.e., a core/sheath configuration), the elastic fibers may comprise the compositional chemical composition of the core.
Samples are generated and analyzed for various characteristics. Note that the gsm referred to in the description of the samples is the target gsm, while the measured gsm is in table 1. It is also noteworthy that each of samples 1-4 was produced using the process described herein, which provides increased thickness per gsm of material compared to conventional processing. Each of samples 1-4 included two carded webs that were integrated, and the two carded webs included the same blend of fibers, i.e., a homogenous configuration.
Sample 1: a 55gsm spunlace material comprising 30 wt% viscose cellulose, 1.7 dtex; 40% by weight of polyethylene terephthalate, 4.4 dtex; and 30 wt% polyethylene terephthalate/polyethylene bicomponent, 2.2 dtex.
Sample 2: a 55gsm spunlace material comprising 30 wt% viscose cellulose, 1.7 dtex; 40% by weight of polyethylene terephthalate, 4.4 dtex; and 30 wt% polyethylene terephthalate/polyethylene bicomponent, 5.8 dtex.
Sample 3: a 55gsm spunlace material comprising 30 wt% viscose cellulose, 1.7 dtex; 40% by weight of polyethylene terephthalate, 10 dtex; and 30 wt% polyethylene terephthalate/polyethylene bicomponent, 2.2 dtex.
Sample 4: a 55gsm spunlace material comprising 30 wt% viscose cellulose, 1.7 dtex; 35% by weight of polyethylene terephthalate, 6.7 dtex; and 35 wt% polyethylene terephthalate/polyethylene bicomponent, 5.8 dtex.
Sample 5: a 50gsm conventional spunlace material comprising 40 wt% viscose cellulose, 1.7 dtex; 20% by weight of polyethylene terephthalate fibers, 4.4 dtex; and 40 wt% polypropylene/polyethylene bicomponent fiber, 1.7 dtex.
Sample 6: processing of 75gsm conventional spunlace: the first and second laminae are homogeneous, wherein each lamina has: 20% of round viscose rayon, 1.7 dtex; 40% polyethylene terephthalate/polyethylene bicomponent, 5.8 dtex; and 40% hollow spiral polyethylene terephthalate fiber, 10 dtex. The third layer had 80% viscose rayon, 1.7 dtex; and 20% polyethylene terephthalate hollow helical fiber, 10 dtex.
Sample 7: processing of 70gsm conventional spunlace: the first and second laminae are homogeneous, wherein each lamina has: 20% by weight of viscose cellulose, 1.7 dtex; 30% by weight of a polyethylene terephthalate/co-polyethylene terephthalate bicomponent, 7 dtex; and 50 wt% polyethylene terephthalate hollow helical fiber, 10 dtex.
A plurality of characteristics of each sample was evaluated. Table 1 shows the results of the compressed thickness method disclosed herein for samples 1-7.
TABLE 1
Recall that samples 1-4 represent nonwoven materials constructed according to the present disclosure, while samples 5-7 are nonwoven materials that are commercially available or made by conventional hydroentangling processes. As shown in Table 1, in most cases, the total compression of samples 1-4 was at least twice the total compression of samples 5-7. The fluid management layers of the present disclosure may exhibit a total compression of greater than 0.35mm, more preferably greater than 0.40mm, or most preferably greater than 0.42mm, specifically including all values within these ranges and any ranges formed therefrom. The fluid management layers of the present disclosure may also exhibit a total recovery of at least 0.30mm, more preferably at least 0.33mm, or most preferably at least 0.35mm, specifically including all values within these ranges and any ranges formed therefrom. For convenience, total compression, total recovery, and percent recovery are derived from the data in table 2.
The fluid management layers of the present disclosure may exhibit a total compression of about 0.40mm to about 0.70mm, more preferably about 0.41mm to about 0.70mm, and most preferably about 0.43mm to 0.7mm, specifically including all values within these ranges and any ranges formed thereby. The fluid management layers of the present disclosure may exhibit an overall recovery of from about 0.35mm to about 0.7mm, more preferably from about 0.36mm to about 0.70mm, and most preferably from about 0.37mm to about 0.70mm, specifically including all values within these ranges and any ranges formed therefrom. The fluid management layers of the present disclosure may exhibit a reduction in thickness of at least about 0.13mm, more preferably at least about 0.15mm, most preferably at least about 0.17mm, as a final thickness measured from 0.5kPa to 1kPa, specifically including all values within these ranges and any ranges formed therefrom. The fluid management layers of the present disclosure may exhibit a reduction in thickness of from about 0.13mm to about 0.30mm, more preferably from about 0.15mm to about 0.30mm, most preferably from about 0.17mm to about 0.30mm, as a final thickness measured from 0.5kPa to 1kPa, specifically including all values within these ranges and any ranges formed thereby. The fluid management layers of the present disclosure may exhibit a reduction in thickness of at least about 0.20mm, more preferably at least about 0.25mm, most preferably at least about 0.30mm, as a final thickness measured from 0.5kPa to 2kPa, specifically including all values within these ranges and any ranges formed therefrom. The fluid management layers of the present disclosure may exhibit a reduction in thickness of from about 0.20mm to about 0.50mm, more preferably from about 0.21mm to about 0.50mm, and most preferably from about 0.25mm to about 0.50mm, as the final thickness measured from 0.5kPa to 2kPa, specifically including all values within these ranges and any ranges formed thereby. The fluid management layers of the present disclosure may exhibit a reduction in thickness of at least about 0.25mm, more preferably at least about 0.30mm, most preferably at least about 0.35mm, as a final thickness measured from 0.5kPa to 3kPa, specifically including all values within these ranges and any ranges formed therefrom. The fluid management layers of the present disclosure may exhibit a reduction in thickness of from about 0.25mm to about 0.60mm, more preferably from about 0.30mm to about 0.60mm, or most preferably from about 0.35mm to about 0.60mm, as the final thickness measured from 0.5kPa to 3kPa, specifically including all values within these ranges and any ranges formed thereby.
As shown, the fluid management layers of the present disclosure can have a density less than or equal to 0.080 g/cc. For example, the fluid management layers of the present disclosure can have a density of 0.020g/cc to 0.080g/cc, more preferably 0.030g/cc to 0.070g/cc, or most preferably 0.035g/cc to 0.065g/cc, specifically including all values within these ranges and any ranges formed therefrom.
Additional data regarding the compression test of each of the samples is provided in table 2 below. The thickness of each of the samples, as measured by the compressed thickness method described herein, is provided in mm at various pressures as follows.
Sample numbering
0.5kPa
1kPa
2kPa
3kPa
5kPa
0.5kPa
Sample 1
0.83
0.67
0.56
0.48
0.39
0.76
Sample 2
0.93
0.74
0.58
0.49
0.39
0.84
Sample 3
1.14
0.97
0.82
0.74
0.65
1.06
Sample No. 4
1.14
0.94
0.78
0.68
0.59
1.07
Sample No. 5
0.54
0.48
0.44
0.41
0.38
0.52
Sample No. 6
0.71
0.63
0.55
0.50
0.44
0.68
Sample 7
0.89
0.81
0.73
0.68
0.62
0.87
TABLE 2
As previously mentioned, capillary action may be useful when the fluid management layer is designed for use in a feminine hygiene article, i.e., for the treatment of menses. Generally, higher capillarity equates to lower air permeability values. The air permeability of the above samples is provided in table 3 below.
Sample numbering
Air permeability (m ^3/m ^2/min)
Standard deviation of
Sample 1
260.89
27.54
Sample 2
340.00
25.87
Sample 3
284.78
4.49
Sample No. 4
355.38
12.17
Sample No. 5
185.55
Sample No. 6
219.56
7.60
Sample 7
318.22
10.78
TABLE 3
However, the desire for increased thickness (to provide a cushion-like soft feel and masking) is diametrically opposed to the desire for high capillarity. Therefore, there should be a balance between thickness and capillary action. The balance is highlighted in table 3.
Based on the data of Table 3, the fluid management layer may have an air permeability of about 200m ^3/m ^2/min to about 400m ^3/m ^2/min, about 220m ^3/m ^2/min to about 375m ^3/m ^2/min, or about 240m ^3/m ^2/min to about 370m ^3/m ^2/min, specifically including all values within these ranges and any ranges formed therefrom.
Recall that an additional benefit of the fluid management layer of the present disclosure is stain masking. The data provided in table 4 illustrates the reduced stain size of the fluid management layer of the present disclosure. For the stain size data below, each of the listed samples was used in an absorbent article having a topsheet that is a hydroformed film with micropores and macropores. This membrane is currently available from Tredegar corp. And each of these absorbent articles had an absorbent core which was an airlaid absorbent core comprising pulp fibers, absorbent gelling material and bicomponent fibers, having a basis weight of 163gsm, available from Glatfelter, York, PA, USA.
Sample numbering
Stain size (cm ^2)
1
36.97
2
45.02
3
36.13
4
40.64
5
54.01
TABLE 4
As shown, the stain size of the fluid management layer of the present disclosure is smaller than that of conventional materials. Absorbent articles according to the present description can have a stain size of less than 50cm 2, less than 47cm 2, or most preferably less than 40cm 2, specifically including all values within these ranges and any ranges formed therefrom. The absorbent articles of the present disclosure can exhibit a stain size of from about 30cm ^2 to about 50cm ^2, more preferably from about 30cm ^2 to about 46cm ^2, or most preferably from about 30cm ^2 to about 42cm ^2, specifically including all values within these ranges and any ranges formed therefrom. For each of the articles tested, a fluid management layer was disposed between the topsheet and the absorbent core.
While the fluid management layers of the present disclosure can provide a soft and more cushioned absorbent article to a user, the fluid management layers of the present disclosure also provide the user with appropriate stiffness so that their resulting absorbent article can reduce the likelihood of bunching. A metric that may determine the stiffness of the fluid management layer is the MD bend length. Data for samples 1-4 are provided in table 5 below.
Sample numbering
MD bending Length (mN/cm)
Sample 1
2.27
Sample 2
1.23
Sample 3
2.52
Sample No. 4
1.62
Sample No. 5
7.3
TABLE 5
The fluid management layer of the present disclosure can have an MD bend length of from about 1mN/cm to about 12mN/cm, more preferably from about 1.2mN/cm to about 12mN/cm, or most preferably from about 1.3mN/cm to about 12mN/cm, specifically including all values within these ranges and any ranges formed therefrom.
Absorbent article
Referring back to fig. 1A and 1B, as previously described, the disposable absorbent articles of the present disclosure may include a topsheet 20 and a backsheet 50. The fluid management layer 30 and absorbent core 40 may be sandwiched between the topsheet and the backsheet. Additional layers may be positioned between the topsheet 20 and the backsheet 50.
The topsheet 20 may be joined to the backsheet 50 by attachment methods such as are known in the art (not shown). The topsheet 20 and the backsheet 50 may be joined directly to each other in the periphery of the article and may be joined together indirectly by joining them directly to the absorbent core 40, the fluid management layer 30 and/or additional layers disposed between the topsheet 20 and the backsheet 50. Such indirect or direct engagement may be accomplished by attachment methods well known in the art.
The topsheet 20 may be compliant, soft feeling, and non-irritating to the wearer's skin. Suitable topsheet materials include liquid pervious materials that are oriented toward and contact the body of the wearer, allowing bodily discharges to pass rapidly therethrough without allowing fluid to pass back through the topsheet to the skin of the wearer. While the topsheet allows for rapid transfer of fluid therethrough, the lotion composition can also be transferred or migrated to the outside or inside of the wearer's skin.
A suitable topsheet 20 may be manufactured from a wide variety of materials, such as woven and nonwoven materials; an apertured film material comprising an apertured formed thermoplastic film, an apertured plastic film and a filament wound apertured film; hydroforming a thermoplastic film; a porous foam; reticulated foam; a reticulated thermoplastic film; a thermoplastic scrim; or a combination thereof.
Apertured film materials suitable for use as topsheets include those apertured plastic films that do not absorb and transmit body exudates and that ensure that fluids transmitted through the topsheet flow back or not at all. Non-limiting examples of other suitable shaped films (including apertured and non-apertured shaped films) are described in more detail in the following patents: U.S. Pat. No. 3,929,135 to Thompson at 30/12/1975; U.S. Pat. No. 4,324,246 to Mullane et al, 4/13 in 1982; U.S. Pat. No. 4,342,314 to Radel et al, 8/3/1982; U.S. Pat. No. 4,463,045 to Ahr et al, 31/7/1984; U.S. Pat. No. 5,006,394 to Baird at 9.4.1991; U.S. Pat. No. 4,609,518 to Curro et al, 9/2/1986; and U.S. Pat. No. 4,629,643, issued to Curro et al, 12/16/1986.
Non-limiting examples of woven and nonwoven materials suitable for use as a topsheet include fibrous materials made from natural fibers (e.g., cotton, including 100% organic cotton), modified natural fibers, synthetic fibers, or combinations thereof. These fibrous materials may be hydrophilic or hydrophobic, but preferably the topsheet is hydrophobic or rendered hydrophobic. As an option, portions of the topsheet can be treated to be hydrophilic by using any known method for making topsheets comprising hydrophilic components. The nonwoven fibrous topsheet 20 can be produced by any known process for making nonwoven webs, non-limiting examples of such processes include spunbonding, carding, wet-laying, air-laying, meltblowing, needle-punching, mechanical winding, thermo-mechanical winding, and hydroentangling.
The topsheet 20 may be formed from a combination of apertured film and nonwoven. For example, the film web and nonwoven web may be combined as described in U.S. patent 9,700,463. Alternatively, the film may be extruded onto the nonwoven material, which is believed to provide enhanced contact between the film layer and the nonwoven material. Exemplary processes for such combination are described in U.S. patents 9,849,602 and 9,700,463.
The backsheet 50 may be positioned adjacent the garment-facing surface of the absorbent core 40 and may be joined thereto by attachment methods such as those well known in the art. For example, the backsheet 50 may be secured to the absorbent core 40 by a uniform continuous layer of adhesive, a patterned layer of adhesive, or a series of separate lines, spirals, or spots of adhesive. Alternatively, the attachment method may include the use of thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other suitable attachment method or combination of these attachment methods as known in the art.
The backsheet 50 may be impervious or substantially impervious to liquids (e.g., urine) and may be manufactured from a thin plastic film, although other liquid impervious flexible materials may also be used. As used herein, the term "flexible" refers to materials that are compliant and readily conform to the general shape and contours of the human body. The backsheet 207 may prevent or at least inhibit the exudates absorbed and contained by the absorbent core 205 from wetting a garment article, such as an undergarment, in contact with the incontinence pad 10. However, the backsheet 50 may allow vapors to escape from the absorbent core 40 (i.e., breathable), while in some cases the backsheet 50 may not allow vapors to escape (i.e., non-breathable). Accordingly, backsheet 50 may comprise a polymeric film, such as a thermoplastic polyethylene film or a polypropylene film. A suitable material for the backsheet 50 is a thermoplastic film having a thickness of, for example, about 0.012mm (0.5 mil) to about 0.051mm (2.0 mils). Any suitable backsheet known in the art may be used in the present invention.
The backsheet 50 acts as a barrier to any absorbent bodily fluids that may pass through the absorbent core 40 to its garment surface, thereby resulting in a reduced risk of staining undergarments or other garments. Preferred materials are soft, smooth, pliable liquid and vapor permeable materials that provide comfortable softness and conformability, and that produce low noise so that no objectionable noise is caused while exercising.
Exemplary backsheets are described in U.S. patent 5,885,265(Osborn, III.) published on 23.3.1999; 6,462,251(Cimini) published at 10/8/2002; 6,623,464(Bewick-Sonntag) published on 23/9/2003 or U.S. Pat. No. 6,664,439(Arndt) published on 16/12/2003. Suitable bi-or multi-layer breathable backsheets for use herein include those exemplified in U.S. patent 3,881,489, U.S. patent 4,341,216, U.S. patent 4,713,068, U.S. patent 4,818,600, EP 203821, EP 710471, EP 710472, and EP 793952.
Suitable breathable backsheets for use herein include all breathable backsheets known in the art. There are two main types of breathable backsheets: a single layer breathable backsheet that is breathable and liquid impervious, and a backsheet having at least two layers that combine to provide breathability and liquid impermeability. Suitable single layer breathable backsheets for use herein include those described in, for example, GB a 2184389, GB a 2184390, GB a 2184391, U.S. patent No. 4,591,523, U.S. patent No. 3989867, U.S. patent No. 3,156,242, and WO 97/24097.
The backsheet is a nonwoven web having a basis weight between about 20gsm and about 50 gsm. In one embodiment, the backsheet is a 23gsm spunbond nonwoven web of relatively hydrophobic 4 denier polypropylene fibers available from Fiberweb Neuberger under the trade name F102301001. The backsheet may be coated with an insoluble liquid swellable material as described in U.S. patent 6,436,508 (ciammachella) published on 8/20 2002.
The backsheet has a garment-facing side and an opposite body-facing side. The garment facing side of the backsheet comprises a non-adhesive region and an adhesive region. The adhesive region may be provided by any conventional method. Pressure sensitive adhesives have generally been found to be very suitable for this purpose.
The absorbent core 40 of the present disclosure may comprise any suitable shape including, but not limited to, oval, circular, rectangular, asymmetric, and hourglass shapes. For example, in some forms of the invention, the absorbent core 205 may have a contoured shape, e.g., narrower in the middle region than in the end regions. As another example, the absorbent core may have a tapered shape with a wider portion at one end region of the pad and tapering to a narrower end region at the other end region of the pad. The absorbent core 40 may include varying stiffness in the MD and CD.
The configuration and construction of the absorbent core 40 may vary (e.g., the absorbent core 40 may have varying caliper zones, a hydrophilic gradient, a superabsorbent gradient, or lower average density and lower average basis weight acquisition zones). In addition, the size and absorbent capacity of the absorbent core 40 can also be varied to accommodate a wide variety of wearers. However, the total absorbent capacity of the absorbent core 40 should be compatible with the design loading and intended use of the disposable absorbent article or incontinence pad 10.
In some forms of the invention, the absorbent core 40 may include multiple functional layers in addition to the first laminate and the second laminate. For example, the absorbent core 40 may include a core wrap (not shown) that may be used to enclose the first and second laminates, as well as other optional layers. The core wrap may be formed from two nonwoven materials, substrates, laminates, films, or other materials. In one form, the core wrap may comprise only a single material, substrate, laminate, or other material that is wrapped at least partially around itself.
The absorbent core 40 of the present disclosure may include one or more adhesives, for example, to help secure the SAP or other absorbent material within the first laminate and the second laminate.
Absorbent cores containing relatively high levels of SAP with various core designs are disclosed in U.S. patent No. 5,599,335 to Goldman et al, EP 1,447,066 to Busam et al, WO 95/11652 to Tanzer et al, U.S. patent publication No. 2008/0312622a1 to huntorf et al, and WO 2012/052172 to Van Malderen. These can be used to construct the superabsorbent layer.
The addition of the core of the present disclosure is contemplated. Specifically, potential additions to current multiple laminate Absorbent cores are described in U.S. Pat. No. 4,610,678 entitled "High-Density Absorbent Structures" issued to Weisman et al on 9/9 1986; U.S. Pat. No. 4,673,402 entitled "Absorbent articules With Dual-Layered Cores" to Weisman et al, 16.6.1987; U.S. Pat. No. 4,888,231 entitled "Absorbent Core Having A Dusting Layer" issued to Angstadt at 19.12.1989; and U.S. Pat. No. 4,834,735 entitled "High Density Absorbent Members Having Low Power Density and Low Basis Weight Acquisition Zones" issued on 30.5.1989. The Absorbent core may further comprise an additional layer which mimics a dual core system comprising an acquisition/distribution core of chemically rigid fibers positioned over an Absorbent storage core, as described in U.S. Pat. No. 5,234,423 entitled "Absorbent Article With Elastic Waist Feature and Enhanced Absorbent Article" issued on 8/10 of 1993; and U.S. Pat. No. 5,147,345. These are useful as long as they do not counteract or conflict with the action of the below-described laminate of the absorbent core of the present invention.
Some examples of suitable absorbent cores 40 that may be used in the absorbent articles of the present disclosure are described in U.S. patent application publications 2018/0098893 and 2018/0098891.
As previously mentioned, absorbent articles comprising a fluid management layer of the present disclosure comprise a storage layer. Referring back to fig. 1A and 1B, the storage layer will generally be positioned in the location in which the absorbent core 40 is depicted. The storage layer may be constructed as described in relation to the absorbent core. The storage layer may comprise a conventional absorbent material. In addition to conventional absorbent materials such as creped cellulose wadding, fluff cellulose fibers, rayon fibers, wood pulp fibers, also known as airfelt, and textile fibers, the storage layer often comprises superabsorbent material which absorbs fluids and forms hydrogels. Such materials are also known as Absorbent Gelling Materials (AGM) and may be included in particulate form. AGMs are generally capable of absorbing large amounts of body fluids and retaining them under moderate pressure. Synthetic fibers may also be used for the second storage layer, including cellulose acetate, polyvinyl fluoride, polyvinylidene 1, 1-dichloride, acrylic resins (such as orlon), polyvinyl acetate, insoluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon), polyesters, bicomponent fibers, tricomponent fibers, mixtures thereof, and the like. The storage layer may also include filler materials such as perlite, diatomaceous earth, vermiculite, or other suitable materials that reduce rewet problems.
The storage layer or fluid storage layer may have a uniform distribution of absorbent gelling material (agm) or may have a non-uniform distribution of agm. agm may be in the form of channels, pockets, strips, criss-cross patterns, swirls, dots, or any other conceivable pattern (two-dimensional or three-dimensional). The AGM may be sandwiched between a pair of fibrous cover layers. Or the AGM may be at least partially encapsulated by a single fibrous cover layer.
Portions of the storage layer may be formed solely of superabsorbent material, or may be formed of superabsorbent material dispersed in a suitable carrier, such as cellulosic fibers or reinforcing fibers in the form of fluff. One example of a non-limiting storage layer is a first layer formed only of superabsorbent material disposed on a second layer formed of superabsorbent material dispersed within cellulosic fibers.
Detailed examples of absorbent cores formed from layers of superabsorbent material and/or layers of superabsorbent material dispersed within cellulosic fibers that can be used in absorbent articles (e.g., sanitary napkins, incontinence articles) detailed herein are disclosed in U.S. patent publication 2010/0228209 a 1. Absorbent cores containing relatively high levels of SAP with various core designs are disclosed in U.S. patent No. 5,599,335 to Goldman et al, EP 1,447,066 to Busam et al, WO 95/11652 to Tanzer et al, U.S. patent publication 2008/0312622a1 to huntorf et al, WO 2012/052172 to Van Malderen, U.S. patent 8,466,336 to carrucci, and U.S. patent 9,693,910 to carrucci. These may be used to construct the second storage layer.
The absorbent article 10 may also include barrier cuffs. Some examples of other suitable barrier cuffs are described in the following patents: U.S. Pat. No. 4,695,278, U.S. Pat. No. 4,704,115, U.S. Pat. No. 4,795,454, U.S. Pat. No. 4,909,803, U.S. patent application publication No. 2009/0312730. Additional suitable barrier cuffs are described in U.S. patent application publications 2018/0098893 and 2018/0098891.
Test method
Fibre dtex (dtex)
Textile webs (e.g., woven, nonwoven, air-laid webs) are composed of individual material fibers. The fibers are measured in terms of linear mass density, which is reported in decitex. The decitex value is 10,000 meters of the mass of the fiber present in the fiber (in grams). The dtex values of the fibers within the web of material are often reported by the manufacturer as part of the specification. If the decitex of the fiber is unknown, it can be calculated by: the cross-sectional area of the fibers is measured via a suitable microscopy technique such as Scanning Electron Microscopy (SEM), the composition of the fibers is determined with a suitable technique such as FT-IR (fourier transform infrared) spectroscopy and/or DSC (dynamic scanning calorimetry), and then the mass of the fibers (in grams) present in 10,000 meters of fibers is calculated using literature values for the density of the composition. All tests were performed in a chamber maintained at a temperature of 23 ℃ ± 2.0 ℃ and a relative humidity of 50% ± 2%, and the samples were conditioned under the same environmental conditions for at least 2 hours prior to testing.
If desired, a representative sample of the web material of interest can be cut from the absorbent article. In this case, the web material is removed in order to not stretch, deform or contaminate the sample.
SEM images were obtained and analyzed as follows to determine the cross-sectional area of the fibers. To analyze the cross-section of a sample of the web material, test samples were prepared as follows. Samples of about 1.5cm (height) by 2.5cm (length) and no creases or wrinkles were cut from the web. The sample was immersed in liquid nitrogen and the edges were broken along the length of the sample with a razor blade (VWR single-edged industrial razor blade No. 9, surgical carbon steel). The samples were sputter coated with gold and then adhered to an SEM mount using double-sided conductive tape (Cu, 3M, available from electron microscopy sciences). Orienting the sample so that the cross-section is as perpendicular as possible to the detector to minimize any of the measured cross-sectionsThe tilt is distorted. SEM images were obtained at a resolution sufficient to clearly elucidate the cross-section of the fibers present in the sample. The fiber cross-section may vary in shape, and some fibers may be composed of multiple individual filaments. Regardless, the area of each of the fiber cross-sections is determined (e.g., using the diameter of a round fiber, the major and minor axes of an elliptical fiber, and for image analysis of more complex shapes). If the fiber cross-section indicates a non-uniform cross-sectional composition, the area of each identifiable component is recorded and the decitex contribution for each component is calculated and then summed. For example, if the fiber is bicomponent, the cross-sectional areas of the core and sheath are measured separately, and the dtex contributions from the core and sheath are calculated separately and summed. If the fiber is hollow, the cross-sectional area does not include an interior portion of the fiber comprised of air, which does not contribute significantly to the fiber dtex. In summary, at least 100 such measurements of the cross-sectional area were made for each fiber type present in the sample, and in square micrometers (μm)2) The cross-sectional area a of each fiber was recorded as a unitkTo an arithmetic mean of (to the nearest 0.1 μm)2)。
Fiber composition is determined using common characterization techniques such as FTIR spectroscopy. For more complex fiber compositions, such as polypropylene core/polyethylene sheath bicomponent fibers, a combination of general techniques (e.g., FTIR spectroscopy and DSC) may be required to fully characterize the fiber composition. This process is repeated for each fiber type present in the web material.
Dtex d of each fiber type in the web materialkThe values are calculated as follows:
dk＝10000m×ak×ρk×10-6
wherein d iskIn grams (per calculated 10,000 meters length), akIn μm2Is a unit, and ρkIn grams per cubic centimeter (g/cm)3) Is a unit. The dtex (accurate to 0.1g (per calculated 10,000 meter length)) and fiber type (e.g., PP, PET, cellulose, PP/PET bicomponent) are reported.
Basis weight
The basis weight of the test sample is the mass (in grams) per unit area (in square meters) of the individual material layers and is measured according to the pharmacopoeia method WSP 130.1. The mass of the test sample was cut to a known area and the mass of the test sample was determined using an analytical balance accurate to 0.0001 grams. All measurements were performed in a laboratory maintained at 23 ℃ ± 2 ℃ and 50% ± 2% relative humidity, and the test samples were conditioned in this environment for at least 2 hours prior to testing.
Measurements were made on test samples taken from rolls or sheets of stock material or from material layers removed from absorbent articles. When cutting the material layer from the absorbent article, care is taken not to cause any contamination or deformation of the layer during the process. The layer cut off should be free of residual adhesive. To ensure that all of the adhesive is removed, the layer is soaked in a suitable solvent that will dissolve the adhesive without adversely affecting the material itself. One such solvent is THF (tetrahydrofuran, CAS 109-99-9, which is available for general use from any convenient source). After the solvent soak, the material layer is allowed to air dry thoroughly in a manner that prevents excessive stretching or other deformation of the material. After the material had dried, a test sample was obtained. The sample must be as large as possible to account for any inherent material variability.
The dimensions of the single layer specimens were measured using a calibrated steel metal ruler from NIST or equivalent. The area of the sample was calculated and recorded to the nearest 0.0001 square centimeter. An analytical balance was used to obtain the mass of the sample and recorded to the nearest 0.0001 gram. Basis weight was calculated by dividing the mass (in grams) by the area (in square meters) and reported to the nearest 0.01 grams per square meter (gsm). In a similar manner, a total of ten replicate test samples were repeated. The arithmetic mean of the basis weights was calculated and reported to the nearest 0.01 grams per square meter.
Air permeability
The air permeability measurements provided herein were obtained using the Worldwide Strategic Partiners (WSP) Test Method 70.1.
Thickness of
The thickness (caliper or thickness) of a test specimen is measured as the distance between a reference platform on which the specimen is placed and a pressure foot that applies a specified amount of pressure to the specimen for a specified amount of time. All measurements were performed in a laboratory maintained at 23 ℃ ± 2 ℃ and 50% ± 2% relative humidity, and the specimens were conditioned in this environment for at least 2 hours prior to testing.
The thickness was measured with a manually operated micrometer equipped with a pressure foot capable of applying a steady pressure of 0.50kPa ± 0.01kPa on the test specimen. The manually operated micrometer is a dead weight type instrument, which reads to the nearest 0.01 mm. A suitable instrument is Mitutoyo series 543ID-C Digimatic from VWR International, or an equivalent instrument. The pressure foot is a flat circular movable surface of smaller diameter than the sample and capable of applying the required pressure. A suitable pressure foot has a diameter of 25.4mm, but smaller or larger pressure feet may be used depending on the size of the sample being measured. The test specimen is supported by a horizontal flat reference platform that is larger than and parallel to the surface of the pressure foot. The system was calibrated and operated according to the manufacturer's instructions.
If necessary, the test sample is obtained by taking it out of the absorbent article. When cutting the test sample from the absorbent article, care is taken not to cause any contamination or deformation to the test sample layer during this process. The test specimens were taken from areas without creases or wrinkles and had to be larger than the pressure foot.
To measure the thickness, the micrometer is first zeroed relative to a horizontal flat reference platform. The test specimen is placed on the platform with the test position centered under the pressure foot. The pressure foot was gently lowered at a rate of 3.0mm + -1.0 mm per second drop until the full pressure was applied to the test specimen. Wait 5 seconds and then record the thickness of the test specimen to the nearest 0.001 mm. In a similar manner, a total of ten replicate test specimens were replicated. The arithmetic mean of all thickness measurements was calculated and reported as "thickness" to the nearest 0.001 mm.
Coefficient of thickness
The caliper factor as previously described is the caliper per 10gsm of sample basis weight. Therefore, the formula is thickness/(basis weight/10).
Density of
The density was calculated based on basis weight and thickness and appropriate unit conversions were made to yield g/cc.
Analysis of material composition
The quantitative chemical composition of test samples comprising a mixture of fiber types was determined using ISO 1833-1. All tests were carried out in a laboratory maintained at 23 ℃. + -. 2 ℃ and 50%. + -. 2% relative humidity.
The analysis is performed on test samples taken from rolls or sheets of stock material or from material layers removed from absorbent articles. When cutting the material layer from the absorbent article, care is taken not to cause any contamination or deformation of the layer during the process. The layer cut off should be free of residual adhesive. To ensure that all of the adhesive is removed, the layer is soaked in a suitable solvent that will dissolve the adhesive without adversely affecting the material itself. One such solvent is THF (tetrahydrofuran, CAS 109-99-9, which is available for general use from any convenient source). After the solvent soak, the material layer is allowed to air dry thoroughly in a manner that prevents excessive stretching or other deformation of the material. After the material has dried, a test sample is obtained and tested according to ISO 1833-1 to quantitatively determine its chemical composition.
Compressed thickness
The thickness (caliper or thickness) of a test specimen is measured as the distance between a reference platform on which the specimen is placed and a pressure foot that applies a specified amount of pressure to the specimen for a specified amount of time. For this method, a series of pressures are applied to the test specimen for a specified time with a recovery period in between. All measurements were performed in a laboratory maintained at 23 ℃ ± 2 ℃ and 50% ± 2% relative humidity, and the test specimens were conditioned in this environment for at least 2 hours prior to testing.
The thickness is measured by a manually operated micrometer equipped with a pressure foot, which pressesThe force foot is capable of applying a steady pressure to the test specimen at each of the specified pressures (+ -0.01 kPa) in the step pressure series 0.50kPa, 1.00kPa, 2.00kPa, 3.00kPa, 5.00kPa, and 0.50 kPa. The manually operated micrometer is a dead weight type instrument, which reads to the nearest 0.001 mm. A suitable instrument is Mitutoyo series 543ID-C Digimatic, available from VWR International, or equivalent. The pressure foot is a flat circular movable surface of smaller diameter than the sample and capable of applying the required pressure. A suitable pressure foot has a width of 25cm2But smaller or larger pressure feet may be used depending on the size of the sample being measured. The test specimen is supported by a horizontal flat reference platform that is larger than and parallel to the surface of the pressure foot. The system was calibrated and operated according to the manufacturer's instructions.
A sample is obtained from a sample of the material being evaluated. The test specimens were taken from areas without creases or wrinkles and had to be larger than the pressure foot.
To measure the thickness, it is first ensured that the pressure to be applied to the sample is adjusted to the first pressure in the series of step pressures of 0.50 kPa. The micrometer is now zeroed for a horizontal flat reference platform. The test specimen is placed on the platform with the test position centered under the pressure foot. The pressure foot was gently lowered at a rate of 3.0mm + -1.0 mm per second drop until the full pressure was applied to the test specimen. Wait 4 seconds and then record the thickness of the test specimen to the nearest 0.001mm and record the applied test pressure. The pressure on the test specimen is removed and a 30 second timer is set to the nearest 0.1 seconds (any convenient source). The pressure is now adjusted to the next pressure setting in the step series of 1.00kPa and the micrometer is zeroed for a horizontal flat reference platform. After 30 seconds, the test specimen is placed on the platform with the same test position centered under the pressure foot. In a similar manner, the pressure foot is lowered and the thickness of the test specimen is recorded to the nearest 0.001mm and the applied pressure is recorded. The pressure on the test specimen was removed and a 30 second timer was set. This entire process is repeated for each pressure in the series of step pressures, in the following order: 0.50kPa, 1.00kPa, 2.00kPa, 3.00kPa, 5.00kPa, 0.50 kPa. The thickness of each pressure was recorded to the nearest 0.001mm and the applied pressure was recorded. For a pressure setting of 0.50kPa, an initial pressure of 0.50kPa and a final pressure of 0.50kPa and thickness, respectively, were recorded. For each pressure applied, the caliper foot is applied to the same test location on the test specimen.
In a similar manner, a total of three replicate test specimens were replicated. The arithmetic mean of the thickness measurements at each pressure was calculated and reported as "thickness" to the nearest 0.001mm, and the applied pressure for each measurement was recorded, along with the "initial pressure" and "final pressure" set for 0.50 kPa. From these results, the thickness reduction can be calculated between any pressure settings used as follows: the thickness obtained at the higher pressure was simply subtracted from the thickness obtained at the lower pressure and reported to the nearest 0.001 mm.
Repeated collection time and rewet
Acquisition time of absorbent articles incorporating Artificial Menses (AMF) as described herein was measured using a strike through plate (strikethrough plate) and an electronic circuit interval timer. The time required for the absorbent article to acquire a series of doses of AMF is recorded. After the collection test, a rewet test was performed. All tests were carried out in a laboratory maintained at 23 ℃. + -. 2 ℃ and 50%. + -. 2% relative humidity.
Referring to fig. 4 to 6B, a moisture-permeable plate 9001 is made of plexiglas having overall dimensions of 10.2cm long × 10.2cm wide × 3.2cm high. The longitudinal slot 9007 extending the length of the plate is 13mm deep, 28mm wide at the top plane of the plate, and the side walls slope downwardly at 65 ° to 15mm wide side walls. The central test fluid well 9009 is 26mm long, 24mm deep, 38mm wide at the top plane of the plate, and the sidewalls slope downward at 65 ° to 15mm wide sidewalls. At the base of the test fluid well 9009, there is an "H" shaped test fluid reservoir 9003 which opens to the bottom of the plate to introduce fluid onto the test sample below. Test fluid reservoir 9003 has an overall length of 25mm, a width of 15mm and a depth of 8 mm. The longitudinal leg of the reservoir is 4mm wide and has a rounded end with a radius 9010 of 2 mm. The legs are 3.5mm apart. The center stays have a radius 9011 of 3mm,and accommodates opposing electrodes spaced 6mm apart. The side walls of the reservoir curve outwardly at a radius 9012 of 14mm defined by an overall width 2013 of 15 mm. Two wells 9002(80.5mm long x 24.5mm wide x 25mm deep) located outside the transverse slots were filled with lead shot (or equivalent) to adjust the overall mass of the plate, providing 0.25psi (17.6 g/cm) for the test area2) The confining pressure of (1). The electrodes 9004 are embedded in the plate 9001, connecting the external banana jack 9006 to the inner wall 9005 of the fluid reservoir 9003. A circuit interval timer is inserted into the jack 9006, and the impedance between the two electrodes 9004 is monitored, and the time from introduction of the AMF into the reservoir 9003 until the AMF is expelled from the reservoir is measured. The timer has a resolution of 0.01 seconds.
For the rewet portion of the test, the pressure applied to the test sample was 1.0 psi. The rewet weight was constructed such that the dimensions of the bottom surface of the weight matched the dimensions of the moisture permeable plate, and the total mass required was calculated to provide a pressure of 1.0psi on the bottom surface of the weight. Thus, the bottom surface of the weight was 10.2cm long by 10.2cm wide and was constructed of a flat, smooth, rigid material (e.g., stainless steel) to provide a mass of 7.31 kg.
For each test sample, seven layers of filter paper cut to 150mm diameter were used as the rewet substrate. Prior to testing, the filter paper was conditioned at 23 ℃. + -. 2 ℃ and 50%. + -. 2% relative humidity for at least 2 hours. A suitable filter paper has a basis weight of about 74gsm, a thickness of about 157 microns, a medium porosity, and is available from VWR International as grade 413.
The test samples were removed from all packages, taking care not to press or pull the product during handling. No attempt was made to smooth wrinkles. Prior to testing, the test samples were conditioned at 23 ℃. + -. 2 ℃ and 50%. + -. 2% relative humidity for at least 2 hours. The dosing position is determined as follows. For a symmetrical sample (i.e., the front of the sample has the same shape and size as the back of the sample when divided laterally along the midpoint of the longitudinal axis of the sample), the dosing location is the intersection of the midpoint of the longitudinal axis of the sample and the midpoint of the lateral axis. For an asymmetric sample (i.e., the front of the sample does not have the same shape and size as the back of the sample when divided laterally along the midpoint of the longitudinal axis of the sample), the dosing location is the intersection of the midpoint of the longitudinal axis of the sample and the lateral axis at the midpoint of the wings of the sample.
The required mass of the wet out plate must be calculated for the particular size of the test sample so that a confining pressure of 0.25psi is applied. The lateral width of the core at the dosing position was measured and recorded to the nearest 0.1 cm. The desired mass of the wet through sheet was calculated as the core width times the length of the wet through sheet (10.2cm) times 17.6g/cm2And the required mass was recorded to the nearest 0.1 g. Lead shot (or equivalent) is added to the well 9002 in the strike-through plate to obtain the calculated mass.
An electronic circuit interval timer is connected to the strikethrough plate 9001 and the timer is zeroed. The test specimen is placed on a flat, horizontal surface with the body side facing up. The strike-through plate 9001 is gently placed over the center of the test sample, ensuring that the "H" shaped reservoir 9003 is centered on the determined dosing position.
Using a mechanical pipette, 3.00mL ± 0.05mL of AMF was accurately pipetted into the test fluid reservoir 9003. Within 3 seconds or less, fluid is dispensed along the molded lip of the bottom of the reservoir 9003 without splashing. After the fluid has been collected, the collection time is recorded to the nearest 0.01 seconds and a 5 minute timer is started. In a similar manner, a second dose and a third dose of AMF were applied to the test fluid reservoir with a 5 minute wait time between each dose. The acquisition time was recorded to the nearest 0.001 seconds. Immediately after the third dose of AMF had been obtained, a 5 minute timer was started and the filter paper of the rewet portion was prepared for testing.
The mass of the 7-ply filter paper was obtained and recorded as dry massfpTo the nearest 0.001 g. When 5 minutes had elapsed after the third collection, the wet-out plate was gently removed from the test sample and set aside. 7 layers of pre-weighed filter paper were placed on the test specimen, the stack was centered on the dosing position. The rewet weight is now placed centrally on top of the filter paper and a 15 second timer is started. Once 15 seconds had elapsed, the rewet weight was gently removed and set aside. The mass of the 7-ply filter paper was obtained and recorded as the wet massfpTo the nearest 0.001 g. From wet massfpMinus dry massfpAnd reported as the rewet value to the nearest 0.001 grams. Before testing the next sample, the electrode 9004 was thoroughly cleaned and any residual test fluid was wiped from the bottom surface of the strike-through plate and rewet weight.
Immediately after the rewet portion of the test, a stain size method was performed using a quantitative test sample, as described herein.
In a similar manner, the entire procedure was repeated for ten replicate samples. The values reported are the arithmetic average of ten separately recorded acquisition time (first, second and third) measurements (accurate to 0.001 seconds) and rewet values (accurate to 0.001 grams).
Stain size measurement method
The method describes how to measure by the size of fluid stains visible on an absorbent article. This procedure is performed on the test sample immediately after the test sample has been added to the test fluid according to a separate method as described herein (e.g., a repeated collection and rewet method). The resulting test samples were photographed under controlled conditions. Each photographic image was then analyzed using image analysis software to obtain a measurement of the size of the resulting visible stain. All measurements were performed at constant temperature (23 ℃. + -. 2 ℃) and relative humidity (50%. + -. 2%).
The test specimen is placed horizontally with a calibrated ruler (traceable to NIST or equivalent standard) on a matte black background inside a light box that provides stable uniform illumination throughout the base of the light box. A suitable light box is Sanoto MK50 (Sanoto, guangdong, china) or equivalent, which provides 5500LUX of illumination at a color temperature of 5500K. A Digital Single Lens Reflex (DSLR) camera (e.g., Nikon D40X or equivalent available from Nikon inc. of tokyo, japan) with manual setting controls is mounted directly above the top opening of the light box so that the entire article and scale are visible within the field of view of the camera.
The white balance of the camera is set for the lighting conditions within the light box using a standard 18% Gray Card (e.g., Munsell 18% reflection (Gray) Neutral Patch/Kodak Gray Card R-27, available from X-Rite; Grand ratings, MI, or equivalent). The manual settings of the camera are set so that the image is correctly exposed so that there is no signal cut in any color channel. Suitable settings may be an f/11 aperture setting, an ISO setting of 400, and a shutter speed setting of 1/400 seconds. The camera was mounted approximately 14 inches above the article at a focal length of 35 mm. The image is correctly focused, photographed and saved as a JPEG file. The resulting image must contain the entire test sample and a distance scale with a minimum resolution of 15 pixels/mm.
To analyze The image, it is transferred to a computer running image analysis software (suitable software is MATLAB, available from The Mathworks, Inc, Natick, MA, or equivalent instruments). The image resolution is calibrated using a calibrated distance scale in the image to determine the number of pixels per millimeter. The images were analyzed by manually drawing the region of interest (ROI) boundaries around the visually discernable perimeter of the stain formed by the prior quantitative test liquid. The area of the ROI was calculated and reported as the total stain area to the nearest 0.01mm2Also noted is which method is used to generate the test sample being analyzed (e.g., repeated collection and rewet).
This entire procedure was repeated for all replicate test samples generated by the quantitative dosing method. The reported values are the average of the measurements recorded separately for the total stain area, accurate to 0.01mm2Also noted is which method is used to generate the test sample being analyzed (e.g., repeated collection and rewet).
Preparation of Artificial menses liquid (AMF)
Artificial Menstrual Fluid (AMF) consists of a mixture of defibrinated sheep blood, phosphate buffered saline solution and mucus components. AMF was prepared such that it had a viscosity between 7.15 and 8.65 centistokes at 23 ℃.
The viscosity of the AMF was measured using a low viscosity rotational viscometer (a suitable Instrument is a Cannon LV-2020 rotational viscometer with UL adapter, State College, PA, or equivalent Instrument). A spindle of appropriate size within the viscosity range is selected and the instrument is operated and calibrated according to the manufacturer. The measurement was carried out at 23 ℃. + -. 1 ℃ and at 60 rpm. The results were recorded to the nearest 0.01 centistokes.
Reagents required for AMF production include: defibrinated sheep blood (collected under sterile conditions, available from Cleveland Scientific, inc., Bath, OH, or equivalent) with a packed cell volume of 38% or greater, gastric mucin (crude form, available from sterized American Laboratories, inc., Omaha, NE, or equivalent) with a viscosity target of 3-4 centistokes when prepared as a 2% aqueous solution, 10% v/v aqueous lactic acid, 10% w/v aqueous potassium hydroxide, anhydrous disodium hydrogen phosphate (reagent grade), sodium chloride (reagent grade), sodium dihydrogen phosphate monohydrate (reagent grade), and distilled water, each available from VWR International or equivalent sources.
The phosphate buffered saline solution consisted of two separately prepared solutions (solution a and solution B). To prepare 1L of solution A, 1.38. + -. 0.005g of sodium dihydrogen phosphate monohydrate and 8.50. + -. 0.005g of sodium chloride were added to a 1000mL volumetric flask and the volume was increased by adding deionized water. And mixing well. To prepare 1L of solution B, 1.42. + -. 0.005g of anhydrous disodium hydrogen phosphate and 8.50. + -. 0.005g of sodium chloride were added to a 1000mL volumetric flask and the volume was increased by adding deionized water. And mixing well. To prepare the phosphate buffered saline solution, 450 ± 10mL of solution B was added to a 1000mL beaker and stirred at low speed on a stir plate. A calibrated pH probe (accurate to 0.1) was inserted into the beaker of solution B and sufficient solution a was added while stirring to bring the pH to 7.2 ± 0.1.
The mucus component is a mixture of phosphate buffered saline solution, aqueous potassium hydroxide solution, gastric mucin, and aqueous lactic acid solution. The amount of gastric mucin added to the mucus component directly affects the final viscosity of the AMF produced. To determine the amount of gastric mucin required to achieve AMF within the target viscosity range (7.15-8.65 centistokes at 23 ℃), 3 batches of AMF were prepared with varying amounts of gastric mucin in the mucus component and then interpolated from the concentration versus viscosity curve using a three point least squares linear fit to obtain the exact amount required. The success range for gastric mucin is typically between 38 grams and 50 grams.
To prepare about 500mL of the mucus component, 460. + -.10 mL of the previously prepared phosphate buffered saline solution and 7.5. + -. 0.5mL of a 10% w/v aqueous potassium hydroxide solution were added to a 1000mL heavy glass beaker. The beaker was placed on a stirred hot plate and the temperature was raised to 45 ℃. + -. 5 ℃ while stirring. A predetermined amount of gastric mucin (± 0.50g) was weighed and slowly sprinkled into the previously prepared liquid that had reached 45 ℃ without coagulation. The beaker was covered and mixing continued. The temperature of the mixture is brought to above 50 ℃ but not more than 80 ℃ within 15 minutes. While maintaining this temperature range, heating was continued for 2.5 hours with gentle stirring. After 2.5 hours, the beaker was removed from the hot plate and cooled to below 40 ℃. Then 1.8. + -. 0.2mL of 10% v/v aqueous lactic acid was added and mixed well. The mucus component mixture was autoclaved at 121 ℃ for 15 minutes and cooled for 5 minutes. The mixture of mucus components was removed from the autoclave and stirred until the temperature reached 23 ℃ ± 1 ℃.
The temperature of the sheep blood and mucus components was allowed to reach 23 ℃. + -. 1 ℃. The volume of the entire batch of previously prepared mucus component was measured using a 500mL graduated cylinder and added to a 1200mL beaker. An equal amount of sheep blood was added to the beaker and mixed well. The viscosity method described previously was used to ensure that the viscosity of AMF was between 7.15 and 8.65 centistokes. If not, the batch is disposed of and another batch is made as needed for adjusting the mucus component.
Unless intended for immediate use, the qualified AMF should be refrigerated at 4 ℃. After preparation, AMF can be stored in an airtight container at 4 ℃ for up to 48 hours. Before testing, AMF must be brought to 23 ℃. + -. 1 ℃. After the test is complete, any unused portions are discarded.
MD bending length
The measurements of MD bend length provided herein were obtained using the Worldwide Strategic Partiners (WSP) test method 90.1.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, 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".
Each document cited herein, including any cross-referenced or related patent or application, is hereby incorporated 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 any disclosure of the invention or the claims herein or that it alone, or in combination with any one or more of the 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.
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.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：用于移动卧床不起的患者的装置和方法