US20040237235A1

US20040237235A1 - Multipurpose disposable applicator

Info

Publication number: US20040237235A1
Application number: US10/858,318
Authority: US
Inventors: Donna Visioli; James Kane; Shanna Moore
Original assignee: Individual
Current assignee: EIDP Inc
Priority date: 2003-06-02
Filing date: 2004-06-01
Publication date: 2004-12-02
Also published as: WO2004108036A1

Abstract

A disposable multi-purpose applicator or wipe designed to desorb and distribute a liquid while protecting persons using the applicator from contact with the liquid is disclosed. The wipe comprises (a) a first top layer of an absorbent material comprising at least one layer of non-woven material; (b) a second layer of liquid impermeable material underlying the first top layer, wherein the first top layer and second layer are joined together at their margins, or portions thereof, to form a peripheral seal, and (c) at least one liquid absorbed into the top layer. The applicator or wipe can be folded and the edges adhered in a peelable seal to enclose the absorbent layer(s) and the absorbed liquid in a liquid impermeable package comprised of the second layer of liquid impermeable material and the peelable seal. Also described are methods for preparing and using the applicator.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Applicant claims the benefit of priority to provisional application 60/475,725 filed Jun. 2, 2003; herein incorporated by reference in its entirety.[0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to disposable applicators or wipes that are designed to desorb and distribute a liquid while protecting persons using the applicator from contact with the liquid in a wide variety of applications, including in the medical, personal care, cosmetic, household and industrial fields, as well as methods and apparatus for making such applicators.

2. Description of the Related Art

Applicators or wipes comprising absorbent and/or absorbent material have been known for some time. Typically, these wipes have been used to absorb liquids (for example, to clean up spilled liquids, or to absorb bodily fluids during medical treatment). They have also been used to transfer liquids from a source to a surface by absorbing the liquid and wiping the surface with the applicator.

Typical wipes comprise a single layer of absorbent material that allows contact between the absorbed liquid and the user. For example, conventional wipes have included an air laid web of fibers, which are uniformly mixed or distributed throughout the web. The wipes have included polymeric fibers such as polyester, polyethylene and polypropylene and natural or synthetic fibers such as cellulosic fibers. Other conventional wet wipes have included a coformed web of polypropylene and cellulosic fibers wherein the fibers are uniformly mixed throughout the web.

However, it is desirable to minimize contact between a user's skin and the liquid absorbed into the wipes.

U.S. Pat. Nos. 4,813,944 and 4,925,453 describe absorbent pads that comprise liquid impermeable layers attached to absorbent layers for absorbing liquids such as bodily fluids. U.S. Pat. No. 5,771,524 discloses an applicator pad comprising an absorbent base layer and a barrier layer.

Wipes have also been packaged with liquid preabsorbed into the wipe. For example, disinfectant solutions have been absorbed into disposable wipes and packaged individually in liquid impermeable packages to provide a sterile, disinfectant wipe. More recently, wipes have been prepared preabsorbed with a variety of cleansing solutions, solvents, waxes, polishes and the like for household and cosmetic uses. Wet wipes have become well known commercial consumer products, which have been available in many forms. The wet wipes have been made from a variety of materials, which have been moistened with a variety of suitable wiping solutions. Such wet wipes have been used for baby wipes, hand wipes, household cleaning wipes, industrial wipes and the like. For example, see U.S. Pat. No. 6,028,018 for a multilayer wet wipe comprising layers of different nonwoven materials. Typically, in these applications, a number of wipes are enclosed in a liquid impermeable package, such as a tub, a canister with a fitment to dispense the wipes, or a flexible pouch, from which the consumer removes the wipes as needed. Multi-wipe packages, however, have certain disadvantages. For example, once the customer unseals the package, the liquid absorbed into the wipes can evaporate on storage and the wipes dry out, rendering them ineffective for their intended purpose. In some cases, excess liquid is provided in the package to extend the shelf life of the wipes after the package is opened, which results in waste and added cost of the product.

It can also be problematic to dispense wipes from such packages, particularly if contact between the preabsorbed liquid and the user's skin is to be avoided.

Therefore, it is desirable to develop a wipe in which contact between the preabsorbed liquid and the user's skin is avoided. It is also desirable to provide such a wipe in a form that will contain and preserve the preabsorbed liquid until the consumer is ready to use the wipe.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an applicator or wipe designed to desorb and distribute a liquid while protecting persons using the applicator from contact with the liquid. Additionally, it is an object of this invention to provide the applicator or wipe in a form that contains and preserves a preabsorbed liquid until it is used. It is another object of the present invention to provide methods and apparatus for making such applicators in substantial quantities and at low cost.

In one aspect of the invention, this invention provides an applicator or wipe characterized by the ability to desorb and distribute a liquid while protecting persons using the applicator from contact with the liquid comprising:

(a) a first top layer of an absorbent layer comprising at least one layer of non-woven material;

(b) a second layer of liquid impermeable material underlying the first top layer, wherein the first top layer and second layer are joined together at their margins, or portions thereof, to form a peripheral seal, and

(c) at least one liquid absorbed into the first top layer.

In one embodiment, the top and second layers are joined together along the entire perimeter of the first top layer to form a peripheral seal, the peripheral seal defining a closed area within the second layer.

In a preferred embodiment, this invention provides the applicator described above, having a center axis dividing the surface of the absorbent top layer into two equal faces and dividing the margins of the second layer of liquid impermeable material into two opposite portions, wherein the applicator or wipe is folded along the center axis such that the faces are contacted and the opposite portions are contacted; and the opposite portions are adhered in a peelable seal to enclose the first top layer and the absorbed liquid in a liquid impermeable package comprised of the second layer of liquid impermeable material and the peelable seal to contain and preserve the preabsorbed liquid until it is used.

In an alternate embodiment, the first top absorbent layer and the second impermeable layer are joined together along a portion of the margin of said first top layer to form a peripheral seal, such that a portion of the first top layer is adhered to the second layer and the remainder of the first top layer is not adhered.

In a preferred embodiment, this invention provides the applicator described above, having a center axis dividing the area of the second impermeable layer into two equal faces and dividing the margins of the second layer into two opposite portions, wherein the applicator or wipe is folded along the center axis such that the opposite portions are contacted; and the opposite portions are adhered in a peelable seal to enclose the first top absorbent layer and the absorbed liquid in a liquid impermeable package comprised of the equal faces of the second layer and the peelable seal to contain and preserve the preabsorbed liquid until it is used.

In additional preferred embodiments, this invention provides the applicators described above, further comprising a handle means providing a grasping portion by which the applicator may be grasped and used.

The present invention also provides a method of preparing the aforementioned applicator or wipe comprising the steps of providing an absorbent layer; providing a web of liquid impermeable material; joining said absorbent layer to said web at their margins, or portions thereof, to form a peripheral seal; applying liquid to said absorbent layer; and separating said web into individual applicators or wipes. In a preferred embodiment, this invention also provides the method of preparing the aforementioned applicator or wipe further comprising folding the web along a center axis; and sealing the web in a peelable seal in the dimensions of an individual applicator or wipe. This invention also provides said methods further comprising providing a handle means for said applicator or wipe.

The present invention also provides an apparatus for preparing the aforementioned applicator or wipe comprising a means for joining an absorbent layer to a web of liquid impermeable material at their margins, or portions thereof; a means for applying a liquid to the absorbent layer; and a means for separating said web into individual applicators or wipes.

In a preferred embodiment, the present invention also provides the apparatus for preparing the aforementioned applicator or wipe further comprising a means for folding the web along a center axis; and a means for sealing the web in a peelable seal in the dimensions of an individual applicator or wipe.

This invention also provides said apparatus further comprising means providing a handle means for said applicator or wipe.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of an applicator embodying the principles of the present invention. [0026]
FIG. 2 is a top perspective view of the applicator shown in FIG. 1. [0027]
FIG. 3 is a cross-sectional side view of a preferred embodiment of the applicator wherein the applicator is folded along a center axis and sealed at the edges to form a liquid impermeable package. [0028]
FIG. 4 is a top perspective view of a preferred embodiment of the applicator wherein the applicator is folded along a center axis and sealed at the edges to form a liquid impermeable package. [0029]
FIG. 5 is a top perspective view of an applicator similar to FIG. 1 and having a center axis for folding, but illustrating an embodiment of the handle means. [0030]
FIG. 6 is a top perspective view of an applicator similar to FIG. 1 and having a center axis for folding, but illustrating an alternative embodiment of the handle means.[0031]

DETAILED DESCRIPTION OF THE INVENTION

The terms “applicator” and “wipe” and the like as used herein to describe the same implement and can be used interchangeably. [0032]
One embodiment of this invention provides an applicator or wipe characterized by the ability to desorb and distribute a liquid while protecting persons using the applicator from contact with said liquid comprising (a) a top layer of an absorbent layer comprising at least one layer of non-woven material; (b) a second layer of liquid impermeable material underlying said top layer, the top and second layers being joined together at their margins along the entire perimeter of the top layer to form a peripheral seal, said peripheral seal defining a closed area on the inside of said second layer; and (c) said liquid absorbed into the top layer. [0033]
This embodiment of this invention can be understood by referring to FIGS. 1 and 2, which illustrate the construction of an applicator of this invention. [0034]
FIG. 1 shows a cross section of an applicator or wipe ([0035] 1) of this invention that comprises a top layer (2) of an absorptive layer comprising at least one layer of non-woven material. One embodiment of the absorptive layer comprises a single layer of non-woven material. As illustrated in FIG. 1, an alternate embodiment of the absorptive layer comprises two layers (3) and (4). A second layer (5), in contact with the underside of the top layer, comprises a sheet of moisture impermeable material. In the schematic drawings depicted in FIG. 1 and FIG. 3 (described below), the thickness of the various layers is exaggerated in comparison to the overall dimensions of the applicator. Depending upon its projected use, the applicator is cut or formed to the desired shape and the edges of the absorbent layer (2) are sealed to the liquid impermeable layer into a peripheral seal (6) that defines a closed area on the inside of said second layer to prevent the escape of liquid contained within the absorbent layer. The peripheral seal (6) is sealed by, for example, heat welding and/or compression. In a preferred embodiment, the margins (8) of the moisture impermeable layer (5) extend beyond the peripheral seal (6). A liquid is absorbed into the absorbent layer during preparation of the applicator. FIG. 1 also shows a vertical line A-A′ that bisects the applicator into two equal portions.
FIG. 2 shows a top perspective of the applicator or wipe ([0036] 1) of this invention that comprises a top layer (2) of an absorptive layer comprising at least one layer of non-woven material. In this top perspective, any optional layer(s) of absorbent material underneath the top layer of absorbent material are not shown. A second layer (5), in contact with the underside of the top layer, comprises a sheet of moisture impermeable material. As indicated above, the applicator is cut or formed to the desired shape and the edges of the absorbent layer (2) are sealed to the liquid impermeable layer into a peripheral seal (6) that defines a closed area on the inside of said second layer to prevent the escape of liquid contained within the absorbent layer. In a preferred embodiment, the margin (8) of the moisture impermeable layer (5) extends beyond the peripheral seal (6). FIG. 2 also shows the vertical line A-A′ and a horizontal line B-B′ that define a plane that bisects the applicator into two equal portions.
In a preferred embodiment, this invention provides the applicator described above, having a center axis dividing the surface of said top layer into two equal faces and dividing said peripheral seal into two opposite edges wherein said applicator or wipe is folded along said center axis such that said faces are contacted and said opposite edges are contacted; and said opposite edges are adhered in a peelable seal to enclose said top layer and said absorbed liquid in a liquid impermeable package comprised of said second layer of liquid impermeable material and said peelable seal to contain and preserve the preabsorbed liquid until it is used. [0037]
This embodiment of the invention can be understood by referring to FIGS. 3 and 4. [0038]
FIG. 3 depicts a cross section of a preferred embodiment of the applicator wherein the applicator, which comprises an absorptive layer ([0039] 12) comprising two layers of non-woven material (13) and (14) and a layer of moisture impermeable material (15) in contact with the underside of the absorptive layer (12), forms a liquid impermeable package (11). To form the liquid impermeable package (11), the applicator is folded along an axis that passes through line A-A′ such that the surface of said absorptive layer (12) is divided into two equal faces and that said faces are contacted. The axis B-B′ that passes through line A-A′ divides the peripheral seal described in FIG. 1 into two equal portions (16) and (17) and also divides the margin of the impermeable surface layer extending beyond the peripheral seal into two equal portions (18) and (19). When the applicator is folded along said axis B-B′, the two equal portions of the peripheral seal (16) and (17) and the two equal portions of the margins (18) and (19) are respectively aligned and contacted in a face-to-face manner. The portions of the margins (18) and (19) adjacent to the peripheral seal are adhered in a peelable seal (20) such that the applicator forms the liquid impermeable package (11). The edges (21) and (22) of the margins (18) and (19) are not sealed to provide a grasping area (23) to facilitate opening the peelable seal (20). Optionally, the edges (21) and (22) may be of different dimensions to facilitate separation of said edges forming the grasping area (23). The absorptive layers (13) and (14) and the liquid absorbed therein are fully contained within the package (11). The margins (18) and (19) may optionally include features such as notches or tear regions to facilitate opening the package.
FIG. 4 shows a top perspective view of the preferred embodiment of the applicator wherein the applicator has been folded across an axis defined by the vertical line A-A′ and a horizontal line B-B′, along the line B-B′ to form the liquid impermeable package ([0040] 11) described above. The cover sheet formed by the layer of moisture impermeable material (15) has a margin (5). A portion (18) of said margin (5) is sealed to a corresponding underlying portion (not shown) in a peelable seal (20) to form a liquid impermeable package (11). The edge (24) of the margin (5) is not sealed to a corresponding underlying edge (not shown) to provide grasping areas to facilitate opening the peelable seal. The fold (24) along the line B-B′ is not sealed, so that after severing of the peelable seal, the package may be unfolded.
In this preferred embodiment, the user will open the liquid impermeable package ([0041] 11) by severing the peelable seal (20), opening the applicator by unfolding fold (24) along the center axis B-B′, thereby exposing the top face of the absorbent layer and the liquid contained therein. The user can then hold the applicator with the liquid impermeable cover sheet adjacent to the user's skin and apply and/or distribute the liquid by wiping with the absorbent layer to desorb the liquid.
In an alternate embodiment, the top and second layers of the applicator are joined together along a portion of the margin of said top layer to form a peripheral seal, such that a portion of said absorbent top layer is adhered to the second impermeable layer and the remainder of said top layer is not adhered. In this embodiment, the top absorbent layer may optionally have an area larger than the area of the second impermeable layer. When the area of the top absorbent layer is larger, the top layer may be folded such that it lies within the area of the second impermeable layer. [0042]
In a preferred embodiment, this invention provides the applicator described above, having a center axis dividing the area of said second layer of liquid impermeable material into two equal faces and dividing the margins of said second layer into two opposite portions, wherein said applicator is folded along said center axis such that said opposite portions are contacted; and said opposite portions are adhered in a peelable seal to enclose said top layer and said absorbed liquid in a liquid impermeable package comprised of said equal faces of said second layer and said peelable seal to contain and preserve the preabsorbed liquid until it is used. [0043]
In this embodiment, the user will open the liquid impermeable package by severing the peelable seal, opening the applicator by unfolding along the center axis, thereby exposing the top absorbent layer and the liquid contained therein. The user can then hold the applicator with the liquid impermeable cover sheet adjacent to the user's skin and apply and/or distribute the liquid by wiping with the absorbent layer to desorb the liquid. When the top layer is folded as described above, it may be unfolded to expose the entire area of the top layer. [0044]
The top absorbent layer ([0045] 2) can be made from a variety of materials including meltblown materials, coform materials, air-laid materials, bonded-carded web materials, hydroentangled materials, spunbonded materials, spunlaced materials, and the like; and can comprise synthetic and/or natural fibers. Desirably, the absorbent layer includes fibrous materials that provide an improved appearance and feel to the wipe. Preferably, the absorbent layer comprises thermoplastic polymeric fibers and optionally cellulosic fibers.
Examples of thermoplastic polymeric fibers suitable for use with the present invention include fibers comprising polymers selected from the group consisting of polyolefins such as polypropylene and polyethylene, polyamides, and polyesters such as polyethyleneteraphthalate. Preferred are polyolefins such as polypropylene and polyethylene and polyesters such as polyethyleneteraphthalate. Alternative synthetic fibers that may be suitable include staple nylon and rayon fibers. Examples of natural fibers suitable for use in the present invention include cellulosic fibers such as wood pulp fibers, cotton fibers, flax fibers, jute fibers, silk fibers and the like. [0046]
Depending on the application, the absorbent layer ([0047] 2) of the wipe may include more than one layer, as illustrated in FIG. 1. For example, the absorbent layer may comprise at least one soft and flexible layer (3) and/or at least one strong, resilient layer (4). Soft and flexible layers are desirable when the wipe is used to apply a liquid to a person's skin. Strong and resilient layers may be desirable to provide tensile strength and/or durability for other applications such as scrubbing a hard or rough surface. The soft and flexible layer may include soft polymeric fibers, such as linear low density polyethylene fibers and/or other polymeric fibers having similar properties. The soft polymeric fibers may or may not be combined with natural fibers such as cellulosic fibers. The strong, resilient layer may include resilient polymeric fibers with relatively high tensile strength, such as polypropylene fibers and/or other polymeric fibers having similar properties. Such strong polymeric fibers may or may not be combined with natural fibers such as cellulosic fibers. Desirably, at least one of the layers contains natural fibers such as cellulosic fibers to provide improved thickness and wettability to the basesheet. The natural fibers may also provide void volume within the basesheet that allows for improved moisture retention.
If the absorbent layer of the layered basesheet is a combination of polymeric and natural fibers, such as polypropylene and cellulosic fibers, the relative percentages of the polymeric fibers and natural fibers in the layer can vary over a wide range depending on the desired characteristics of the wet wipes. For example, the layer may comprise from about 20 to about 95 weight percent, desirably from about 20 to about 60 weight percent, and more desirably from about 30 to about 40 weight percent of polymeric fibers based on the dry weight of the layer. Such a layer of polymeric and natural fibers may be manufactured by any method known to those skilled in the art. [0048]
Generally, it is desirable that such a layer be formed by a coform process for a more uniform distribution of the polymeric and natural fibers within the layer. Such coform layers are manufactured generally as described in U.S. Pat. Nos. 4,100,324; 4,604,313 and 5,350,624; which are herein incorporated by reference to the extent they are consistent herewith. Typically, such coform layers comprise a gas-formed matrix of thermoplastic polymeric meltblown microfibers, such as, for example, polypropylene microfibers, and cellulosic fibers, such as, for example, wood pulp fibers. A coform layer is formed by initially forming at least one primary air stream containing the synthetic or polymeric fibers and merging the primary stream with at least one secondary stream of natural or cellulosic fibers. The primary and secondary streams are merged under turbulent conditions to form an integrated stream containing a thorough, homogeneous distribution of the different fibers. The integrated air stream is directed onto a forming surface to air form the layer of material. A multiplicity of these coform layers can then be formed in succession to provide a web of multiple coform layers. [0049]
In a particular embodiment, the absorbent layer of the wipe of the present invention comprises an outermost soft and flexible layer. The outer soft layer may comprise a coformed layer of meltblown linear low density polyethylene microfibers and wood pulp fibers wherein the pulp to polymer weight ratio is from about 50/50 to about 75/25 and desirably about 65/35. A suitable polyethylene is available from Dow under the trade designation DOW 6831A. [0050]
As noted above, the absorbent layer may also comprise a strong resilient layer. The absorbent layer may comprise a single strong resilient layer, or it may comprise an inner strong resilient layer underlying a soft and flexible layer. The strong, resilient layer can comprise a coformed layer of meltblown polypropylene microfibers and wood pulp fibers wherein the pulp to polymer weight ratio is from about 50/50 to about 75/25 and desirably about 65/35. A suitable polypropylene is available from Montel under the trade designation MONTEL PF015. [0051]
A family of polyesters suitable for the absorbent layer of this invention is available from DuPont under the tradename Sontara®. These polyesters comprise spunlaced polyethyleneteraphthalate and optionally other fibers such as, for example, wood fibers and rayon. [0052]
The different fibers in the different layers of the layered absorbent layer of the present invention, such as the polypropylene, polyethylene or polyester microfibers set forth above, typically may not be compatible with and may not bond to each other. However, the different fibers may entangle with each other resulting in suitable securement between the layers. For example, in a layered basesheet containing a coform layer of polyethylene and cellulosic fibers and a coform layer of polypropylene and cellulosic fibers, the polyethylene and polypropylene fibers may entangle with each other and the cellulosic fibers and may at least partially bond to the cellulosic fibers which results in securement between the layers. [0053]
The absorbent layer may be optionally further processed by quilting, embossing and/or needle-punching by mechanical means or other means such as water jets. [0054]
Interlayer bonding and entanglement may be enhanced by a thermo-mechanical process wherein the layered basesheet is passed between a heated smooth anvil roll and a heated pattern roll. The pattern roll may have any raised pattern, which provides the desired entanglement and interlayer bonding. Desirably, the pattern roll defines a raised pattern, which defines a plurality of bond locations, which define a bond area of between about 4 and about 30 percent of the total area of the roll for improved interlayer attachment. [0055]
The pressure between the rolls and the temperature of the rolls must be balanced to produce a basesheet having adequate strength and integrity while maintaining the softness of the outer layers. The temperature and pressure may vary depending upon the types of fibers being used to provide the desired wipe. In a particular embodiment wherein the layers comprise at least one layer of polyethylene fibers and at least one other layer of polypropylene fibers, the pressure between the rolls may be between about 5 and about 90 kilograms per lineal centimeter and the temperature of at least one of the rolls may be between about 65 and about 95° C. for improved entanglement and bonding. Under such conditions of temperature and pressure, the polyethylene fibers deform to provide mechanical entanglement with and possible bonding to the polypropylene fibers. As a result, the layers become entangled and bonded in discrete areas arranged in a pattern, which corresponds to the raised pattern on the pattern roll. [0056]
The layered basesheet for the absorbent layer may have a total basis weight of from about 25 to about 120 grams per square meter and desirably from about 40 to about 90 grams per square meter. Such basis weight of the layered basesheet may also vary depending upon the desired end use of the wipe. For example, a suitable basesheet for wiping the skin may define a basis weight of from about 60 to about 80 grams per square meter and desirably about 75 grams per square meter. In a particular embodiment wherein the layered basesheet includes coform layers of polypropylene and cellulosic fibers and polyethylene and cellulosic fibers, the layered basesheet defines a basis weight of from about 60 to about 90 grams per square meter and desirably about 80 grams per square meter for improved softness and adequate strength. [0057]
Each layer may or may not have a different basis weight depending upon the desired properties such as strength and softness of the wipe. For example, in a two-layer absorbent layer which includes an inner layer of polypropylene and wood pulp fibers and an outer layer of polyethylene and wood pulp fibers, the basis weight of the layers may define an inner/outer layer weight ratio of from about 80/10 to about 20/40, desirably about 50/25 to about 33/33 and more desirably about 40/30 based on a total weight of the basesheet for improved performance. [0058]
The overall thickness of the absorbent layer may be varied as desired depending upon the amount of absorbency required and is typically between about 1 mm to about 15 mm thick. [0059]
Underlying the absorbent layer ([0060] 2) is a layer of liquid impermeable material (5) that forms a liquid impermeable cover sheet that prevents passage of liquid within the absorbent layer to the exterior of the wipe. The liquid impermeable cover sheet covers the face of the absorbent layer and forms an effective barrier between the person using the applicator and the liquid absorbed into the pad. In that regard, the face of the liquid impermeable cover sheet that contacts the nonwoven must be nonabsorbent and impervious to any liquid and must be chemically inert to the liquid.
The impermeable layer suitable for use in the present invention comprises at least one layer of a polymer selected from polymers in the group consisting of polyamides; polyolefins; polyesters; polyethylene vinyl alcohol; polyvinylidene chloride and anhydride-modified ethylene homo- and co-polymers. In a preferred embodiment, the liquid impermeable cover sheet is formed from a polyolefin, such as polyethylene or polypropylene or a polyester such as polyethyleneteraphthalate. [0061]
Polyamides suitable for use herein include aliphatic polyamides, amorphous polyamides, or a mixture thereof. “Aliphatic polyamides” as the term is used herein can refer to aliphatic polyamides, aliphatic copolyamides, and blends or mixtures of these. Preferred aliphatic polyamides for use in the invention are [0062] polyamide 6, polyamide 6.66, blends and mixtures thereof. Polyamides 6.66 are commercially available under the tradenames “Ultramid C4” and “Ultramid C35” from BASF, or under the tradename “Ube5033FXD27” from Ube Industries Ltd. Polyamide 6 is commercially available under the tradename Nylon 4.12 from E.I. du Pont de Nemours and Company, for example.
The impermeable layer may further comprise other polyamides such as those described in U.S. Pat. Nos. 5,408,000; 4,174,358; 3,393,210; 2,512,606; 2,312,966 and 2,241,322, which are incorporated herein by reference. The film may also comprise partially aromatic polyamides. A suitable partially aromatic polyamide is the amorphous copolyamide 6-I/6-T of the following formula: [0063]
Some suitable partially aromatic copolyamides for use in the present invention are the amorphous nylon resins 6-I/6-T commercially available under the tradename Selar® PA from E.I. du Pont de Nemours and Company or commercially available under the tradename [0064] Grivory® G 21 from EMS-Chemie AG, for example.
Polyolefins suitable for use in the present invention are selected from polypropylenes, polyethylene polymers and copolymers. Polyethylenes useful for use herein can be prepared by a variety of methods, including well-known Ziegler-Natta catalyst polymerization (see U.S. Pat. No. 4,076,698 and U.S. Pat. No. 3,645,992 for examples), metallocene catalyst polymerization (see U.S. Pat. No. 5,198,401 and U.S. Pat. No. 5,405,922 for examples) and by free radical polymerization. Polyethylene polymers useful herein can include linear polyethylenes such as high density polyethylene (HDPE), linear low density polyethylene (LLDPE), very low or ultralow density polyethylenes (VLDPE or ULDPE) and branched polyethylenes such as low density polyethylene (LDPE). The densities of polyethylenes suitable for use in the present invention range from 0.865 g/cc to 0.970 g/cc. Linear polyethylenes for use herein can incorporate alpha-olefin comonomers such as butene, hexene or octene to decrease their density within the density range so described. The impermeable layer of the present invention can comprise ethylene copolymers such as ethylene vinyl acetate and ethylene methyl acrylate and ethylene (meth)acrylic acid polymers. Polypropylene polymers useful in the practice of the present invention include propylene homopolymers, impact modified polypropylene and copolymers of propylene and alpha-olefins. [0065]
Polyethylene vinyl alcohol (“EVOH”) having from about 20 to about 50 mole % ethylene can be suitable for use herein. Suitable polyethylene vinyl alcohol polymers are commercially available under the tradename Evalca® from Kuraray or commercially available under the tradename Soarnol® from Nippon Goshei, for example. [0066]
Polyvinylidene chloride (PVDC) suitable for use herein can be obtained commercially from Dow Chemical under the tradename Saran®, for example. [0067]
Examples of coated film include the Mylar RL and Mylar OL films produced by DuPont Teijin Films. [0068]
It may be desirable to match the composition of the impermeable layer and the absorbent layer to provide good layer-to-layer adhesion. For example, if the absorbent layer comprises polyethylene fibers, it may be desirable for the impermeable layer to comprise polyethylene. Alternatively, anhydride or acid-modified ethylene and propylene homo- and co-polymers can be used as extrudable adhesive layers (also known as “tie” layers) to improve bonding of layers of polymers together when the polymers do not adhere well to each other, thus improving the layer-to-layer adhesion in a multilayer structure. Depending on the nature of the innermost layer of the impermeable structure, an additional inner tie layer can optionally be included to provide a desirable level of adhesion to the absorbent layer. The compositions of the tie layers will be determined according to the compositions of the adjoining layers that need to be bonded in a multilayer structure. One skilled in the polymer art can select the appropriate tie layer based on the other materials used in the structure. Various tie layer compositions are commercially available under the tradenames Bynel® or Appeel® from E.I. du Pont de Nemours and Company, for example. [0069]
To form the peelable seal, the impermeable layer can be sealed to itself by any means known in the art, such as laser welding, induction sealing, or preferably heat sealing. The impermeable layer may alternatively be sealed by application of a solvent such as tetrahydrofuran to soften the layers prior to adhering. If heat sealing is used to form the peelable seal, the impermeable layer preferably consists of a bilayer or multilayer coated or coextruded film so that the applied heat does not deform the outermost part of the impermeable layer. Such multilayer structures produced by coating or coextrusion are well known in the flexible packaging art. [0070]
Impermeable films useful in the present invention can additionally comprise optional materials, such as the conventional additives used in polymer films including: plasticizers, stabilizers, antioxidants, ultraviolet ray absorbers, hydrolytic stabilizers, anti-static agents, dyes or pigments, fillers, fire-retardants, lubricants, reinforcing agents such as glass fiber and flakes, processing aids, antiblock agents, release agents, and/or mixtures thereof. [0071]
The wipe may be optionally quilted or embossed by heat and pressure. The wipe may be optionally quilted or embossed in any of a number of ways, such as a pattern of parallel lines or of dots formed by heat and pressure sufficient to deform the layers and compress them together. As noted above, the basic wipe structure may be formed in large sheets and then cut to the desired shape and size. The margins, or portions thereof, of the top layer and the second layer are secured together by any suitable means, such as by heat sealing, application of a solvent such as tetrahydrofuran, or hot melt adhesive, forming a peripheral seal. Sealing the edges of the layers maintains the absorbent layer and any fluids absorbed therein within the boundary of the impermeable cover sheet and prevents migration of such fluids to the outside surface which is an important safety and protection feature of the instant applicator. [0072]
The applicators or wipes of the present invention comprise a liquid that can be absorbed into the wipe basesheet (consisting of the absorbent layer and the impermeable layer as described above) and may include any suitable components which provide the desired wiping properties. For example, the components may include water, solvents, emollients, surfactants, fragrances, preservatives, chelating agents, pH buffers, waxes, polishes or combinations thereof as are well known to those skilled in the art. The liquid may also contain lotions, sunscreen agents, insect repellents and/or medicaments. The desired amount of liquid is applied to the top face of the absorbent layer. The liquid incident upon the surface of the absorbent layer is retained in the interstices or pores until it is desorbed by wiping a surface. During use, the applicator will desorb and distribute the liquid while protecting persons using the applicator from contact with the liquid. [0073]
The amount of liquid contained within each wet wipe may vary depending upon the type of material being used to provide the wet wipe, the type of liquid being used and the desired end use of the wet wipe. Generally, each wet wipe can contain from about 150 to about 600 weight percent and desirably from about 250 to about 450 weight percent liquid based on the dry weight of the wipe for improved wiping. In a particular aspect, the amount of liquid contained within the wet wipe is from about 300 to about 400 weight percent and desirably about 330 weight percent based on the dry weight of the wet wipe. [0074]
Each wet wipe can be generally rectangular in shape and may have any unfolded width and length suitable for its intended application. For example, the wet wipe may have an unfolded length of from about 2.0 to about 40.0 centimeters, alternatively from about 5.0 to about 25.0 centimeters, alternatively from about 10.0 to about 20.0 centimeters; and unfolded width of from about 2.0 to about 40.0 centimeters, alternatively from about 5.0 to about 25.0 centimeters, alternatively from about 10.0 to about 20.0 centimeters. Of note are wipes with an unfolded length of from about 5.0 to about 10.0 centimeters and an unfolded width of from about 5.0 to about 10.0 centimeters. Also of note are wipes with an unfolded length of from about 10.0 to about 20.0 centimeters and an unfolded width of from about 10.0 to about 20.0 centimeters. [0075]
Although the applicator is depicted in the Figures and described as generally rectangular in shape, other shapes can be embodied in the present invention. For example, an applicator having a square shape can be folded along a center axis running diagonally from opposite corners into a package having a generally triangular shape. Alternatively, an applicator having a circular shape can be folded along a center axis running through the diameter of the applicator into a package having a generally semicircular shape. Other shapes may also be envisioned, provided that the shape is symmetrical about a center axis so that, by folding, the areas of the two halves are coequal and coextensive and the margins can be adhered together in a peelable seal. [0076]
In another preferred embodiment, the applicator of this invention is provided with a handle means providing a grasping portion by which the applicator may be grasped and used. The optional handle means is positioned on the outside surface of the liquid impermeable cover sheet so that the grasping portion is isolated from the layer of absorbent material by the liquid impermeable cover sheet. This makes more effective use of the liquid impermeable cover sheet by effectively putting the hand, particularly the fingers and thumb, of the user centrally behind the impermeable sheet. In this manner, the hand of a person using the applicator is effectively shielded from contact with the liquid contained within the applicator. [0077]
The handle means may take many different forms. FIGS. 5 and 6 depict applicators of this invention that are provided with handle means. [0078]
In one embodiment of the present invention the applicator is similar to that described above, except that a handle means is formed integral with the liquid impermeable material forming the cover sheet. FIG. 5 shows an applicator ([0079] 25) wherein the cover sheet (26) is folded longitudinally along line C-C′ to form a gusset or pleat (27) defining a folded flap portion (28) by which the applicator (25) may be grasped by insertion of one or more fingers into the flap opening (29). The ends of the flap portion (30) are secured with the edges of the cover sheets so that the fold lies flat when not in use. Optionally, the fold (31) along line C-C′ is adhered to the cover sheet (26) when the peripheral seals are made. FIG. 5 also illustrates a line D-D′ that defines an axis dividing the applicator (25) into two portions of equal area, one portion (32) comprising the handle means (i.e. the gusset (27)). The other portion (33) of the applicator (25) can be folded along line D-D′ to a position underlying and in contact with portion (33). The two portions (32) and (33) can be adhered at the margins (34) and (35) with a peelable seal as previously described to form a liquid impermeable package.
In an alternative embodiment of the present invention the applicator ([0080] 33) is similar to that described above, except that a handle means is formed of an elongate strip. FIG. 6 shows an applicator (40) wherein the handle means is formed of an elongate strip (41) that is adhesively secured to the liquid impermeable cover sheet (42) at opposite end portions (43) and (44) of the strip. The unsecured middle portion of the strip (45) forms an open loop (46) defining the grasping portion by which the applicator may be handled, but which lays flat when not in use. FIG. 6 also illustrates a line E-E′ that defines an axis dividing the applicator (40) into two portions of equal area, one portion (47) comprising the handle means (i.e. the strip (41)). The other portion (48) of the applicator (40) can be folded along line E-E′ to a position underlying and in contact with portion (47). The two portions (47) and (48) can be adhered at the margins (49) and (50) with a peelable seal as previously described to form a liquid impermeable package.
The layered basesheet for the wipe of the different aspects of the present invention may be provided on a single manufacturing line which includes multiple individual forming banks. Each forming bank is configured to provide an individual layer having the desired properties. For example, a forming bank may be configured to provide the outer, soft layer of the absorbent layer. The mechanical entanglement between the fibers of each layer during the process provides attachment between the layers and may form bonds between the adjacent layers to provide the layered basesheet. Subsequent thermomechanical bonding may also be used on the layered basesheet to improve the attachment between the layers. [0081]
Each forming bank may include the appropriate equipment to provide the desired type of web. For example, if each layer comprises a coform layer of meltblown microfibers and natural fibers such as wood pulp fibers, each forming bank may include a plurality of meltblowing dies as are well known to those skilled in the art. In general, meltblowing processes include meltblowing dies which are configured to extrude a molten polymeric material into fine streams. The fine streams are then attenuated by converging flows of high velocity gas to break the polymer streams into discrete microfibers of small diameter. The stream or streams of natural fibers which are converged with the streams of meltblown microfibers may be provided by a conventional pulp picker roll process as is well known to those skilled in the art. [0082]
Alternatively, one or more layers of the wipe of the different aspects of the present invention can be made from a different type of material such as a meltblown sheet of polymeric microfibers. For example, a strong and resilient layer may include a layer of meltblown polypropylene fibers while a soft layer may include a coform layer of polyethylene and wood pulp fibers as described above. The outer soft and flexible layers may otherwise be provided by different types of materials such as airlaid, carded web, or meltblown materials as are set forth above and which are manufactured by processes well known to those skilled in the art. [0083]
The impermeable layer of the present invention can be prepared by (co)extrusion as follows: granulates of the various components are melted in extruder(s). The molten polymers are passed through a die or set of dies to form layer(s) of molten polymers that are processed as a laminar flow. The molten polymers are cooled to form a layered structure. Molten extruded polymers can be converted into a film using a suitable converting technique. For example, the basesheet for a wipe of the present invention can be made by (co)extrusion of the impermeable layer followed by lamination onto one or more other layers comprising the absorbent layer. Other suitable converting techniques are, for example, blown film extrusion, cast film extrusion, cast sheet extrusion, extrusion coating, dispersion coating and solution coating. A web of basesheet may be prepared wider than the desired width of the finished wipe and can be slit longitudinally into strips of the desired width. [0084]
As indicated above, the present invention also provides a method of preparing the aforementioned applicator or wipe comprising preparing an absorbent layer; preparing a web of liquid impermeable material; joining said absorbent layer to said web at their margins, or portions thereof, to form a peripheral seal; applying liquid to said absorbent layer; and separating said web into individual wipes. In a preferred embodiment, this invention also provides a method of preparing the aforementioned applicator or wipe further comprising folding the web along a center axis; and sealing the web in a peelable seal in the dimensions of an individual wipe. [0085]
For example, a web of absorbent material prepared as described above is cut to length into individual pads by a transverse cutter. The individual pads are advanced away from the strips by a pair of rollers to form a space between successive rows of absorbent pads. [0086]
A web of liquid impermeable film is provided, either withdrawn from a supply roll or from a film fabrication machine, and brought onto the advancing absorbent pads by a pair of rollers. Heated rotating disks press the longitudinal edges and longitudinal land areas of the absorbent web and impervious web together so that such areas of the webs are adhesively secured together with a good seal. [0087]
This invention also provides said methods further comprising providing a handle means for said wipes. In one aspect of this embodiment, strips of handle material may be withdrawn from supply rolls and brought onto the advancing impermeable film to form handle means on the outside surface of the film. In the alternative case of an integrally formed handle, the web of impermeable film is folded longitudinally by conventional folding means to form a gusset or pleat therein defining a folded flap as a handle means. Alternatively, the web may be prefolded and supplied with the gusset or pleat already therein. Transverse bars seal the impermeable web, the absorbent web and the handle means together in the desired lengths for the finished wipe. The seal is applied in a manner to securely attach the ends of the strip or gusset to the film while allowing a free portion to lift away from the film for easy handling of the wipe. Liquid, in an amount desired for the finished wipe, is applied to each area of the absorbent layer corresponding to the area of the finished wipe. [0088]
In a preferred embodiment, the wipe is prepared by folding along a center axis and sealing at the margins to form a liquid impermeable package to contain and preserve the preabsorbed liquid until the consumer is ready to use the wipe. In a preferred embodiment of a method of this invention, the web with liquid applied is folded longitudinally along a central axis so that the longitudinal edges are brought into contact. The longitudinal edges are sealed with a peelable seal. The folded web then passes through a transverse sealer/cutter which seals the transverse edges of the wipes and simultaneously cuts the web into individual wipes. Alternatively, the cutter perforates the web at the seal. This allows the web to be maintained as a strip or roll of attached wipes. Individual wipes can then be dispensed by severing the web at the perforations. [0089]
In this embodiment, the liquid can be applied to the absorbent layer prior to the formation of the peelable seal. Alternatively, portion(s) of the peelable seal may be formed such that there is an opening in the folded applicator, the liquid applied to the absorbent layer through the opening, and the remainder of the peelable seal formed to completely enclose the absorbent layer and the absorbed liquid. For example, the wipe may be folded and sealed on two sides of the package, liquid applied through the open third side opposite the fold, and then the third side is sealed. [0090]
The present invention also provides an apparatus for preparing the aforementioned applicator or wipe comprising a means for joining an absorbent layer to a web of liquid impermeable material at their margins, or portions thereof; means for applying a liquid to the absorbent layer; and a means for separating said web into individual wipes. [0091]
In this embodiment, means for joining an absorbent layer to a web of liquid impermeable material at their margins, or portions thereof, include, for example, means for heat sealing, means for application of a solvent such as tetrahydrofuran, or means for applying hot melt adhesive. Heat sealing means include heated rollers or bars. [0092]
Means for applying a liquid to the absorbent layer include, for example, a liquid reservoir with at least one orifice to dispense the liquid. Additional components may include valves, tubing, measuring devices, and the like, that allow for application of a specific portion of liquid to the absorbent layer. [0093]
Means for separating said web into individual wipes include cutter bars or wheels as described above. [0094]
In a preferred embodiment, the present invention also provides an apparatus for preparing the aforementioned applicator or wipe further comprising a means for folding the web along a center axis; and means for sealing the web in a peelable seal in the dimensions of an individual wipe. Means for folding the web along a center axis include, for example, a forming device to bring the longitudinal margins of the impermeable wipe together in a facing orientation. Means for sealing the web in a peelable seal in the dimensions of an individual wipe include, for example, means for heat sealing, means for application of a solvent such as tetrahydrofuran, or means for applying hot melt adhesive. [0095]
This invention also provides said apparatus further comprising means providing a handle means for said wipes. This means includes, for example, means for supplying a handle means comprising an elongate strip and adhering it to the web of impermeable material. Means for adhering the strip to the web include means for heat sealing, means for application of a solvent such as tetrahydrofuran, or means for applying hot melt adhesive. Typically, these means will adhere the handle means concurrently with other aspects of assembling the wipe such as forming the peripheral seal or the peelable seal. Means for forming an integral handle comprising a pleat or gusset defining a folded flap include, for example, a forming device to bring a portion of the web of impermeable material into an overlying orientation with the remainder of the web. [0096]
In the specification there have been set forth preferred embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. The foregoing has been illustrative of the principles of the present invention as embodied in a preferred form thereof. Various modifications or alternative forms may occur to workers in the art without departing from the spirit and scope of the invention. [0097]

Claims

We claim:

1. An applicator or wipe characterized by the ability to desorb and distribute a liquid while protecting persons using the applicator from contact with said liquid comprising:

(a) a first top layer of an absorbent material comprising at least one layer of non-woven material;

(b) a second layer of liquid impermeable material underlying said first top layer, wherein said first top layer and said second layer are joined together at their margins, or portions thereof, to form a peripheral seal, and

(c) at least one liquid absorbed into said first top layer.

2. The applicator or wipe according to claim 1 wherein said first top layer and said second layer are joined together along the entire perimeter of the top layer to form a peripheral seal, said peripheral seal defining a closed area within the margins of said second layer.

3. The applicator or wipe according to claim 2 having a center axis dividing the surface of said absorbent first top layer into two equal faces and dividing the margins of said second layer of liquid impermeable material into two opposite portions, wherein said applicator is folded along said center axis such that said faces are contacted and said opposite portions are contacted; and said opposite portions are adhered in a peelable seal to enclose said first top layer and said absorbed liquid in a liquid impermeable package comprised of said second layer of liquid impermeable material and said peelable seal.

4. The applicator or wipe according to claim 1 wherein said first top absorbent layer and said second impermeable layer are joined together along a portion of the margin of said first top layer to form a peripheral seal, such that a portion of said first top layer is adhered to said second layer and the remainder of said first top layer is not adhered.

5. The applicator or wipe according to claim 4 having a center axis dividing the area of said second impermeable layer into two equal faces and dividing the margins of said second layer into two opposite portions, wherein said applicator or wipe is folded along said center axis such that said opposite portions are contacted; and said opposite portions are adhered in a peelable seal to enclose said first top absorbent layer and said absorbed liquid in a liquid impermeable package comprised of said equal faces of said second layer and said peelable seal to contain and preserve the said absorbed liquid until it is used.

6. The applicator or wipe according to claim 1 wherein said non-woven material of said first top layer is selected from the group consisting of thermoplastic polymeric fiber, cellulosic fiber, and combinations thereof.

7. The applicator or wipe according to claim 6 wherein said thermoplastic polymeric fiber is selected from the group consisting of polyolefins, polyamides, and polyesters.

8. The applicator or wipe according to claim 1 wherein said second layer of liquid impermeable material comprises at least one layer of polymer selected from the group consisting of polyamides; polyolefins; polyesters; polyethylene vinyl alcohol; polyvinylidene chloride, anhydride-modified ethylene homopolymer, anhydride-modified ethylene copolymer, and combinations thereof.

9. The applicator or wipe according to claim 8 wherein said second layer of liquid impermeable material comprises a polyolefin film.

10. The applicator or wipe according to any of claims 1 through 5 further comprising a handle means providing a grasping portion by which the applicator or wipe may be grasped and used.

11. The applicator according to claim 10 wherein said handle means is formed integral with said second layer of liquid impermeable material.

12. The applicator according to claim 11 wherein said handle means comprises a pleat or gusset defining a folded flap formed in said second layer of liquid impermeable material.

13. The applicator according to claim 6 wherein said handle means comprises an elongated strip attached to said second layer of liquid impermeable material at opposite end portions of said elongated strip with the medial portion thereof being unattached so that the medial portion of said strip forms a loop.

14. A method of preparing the applicator or wipe comprising the steps of:

providing an absorbent layer;

providing a web of liquid impermeable material;

joining said absorbent layer to said web at their margins, or portions thereof, to form a peripheral seal;

applying liquid to said absorbent layer; and

separating said web into individual applicators or wipes.

15. The method of claim 14 further comprising the steps of folding the web along a center axis; and sealing the web in a peelable seal in the dimensions of an individual applicator or wipe.

16. The method of claim 14 or claim 15 further comprising the step of providing a handle means for said applicator or wipe.

17. The method of claim 16 wherein providing said handle means comprises forming a folded flap in said layer of liquid impermeable material and adhering the ends of the flap to the edges of said applicator or wipe.

18. The method of claim 16 wherein providing said handle means comprises attaching an elongated strip to said layer of liquid impermeable material at opposite end portions of said strip with the medial portion thereof being unattached so that the medial portion of said strip forms a loop.

19. An apparatus for preparing the applicator or wipe of claim 1 comprising:

a means for joining an absorbent layer to a web of liquid impermeable material at their margins, or portions thereof;

a means for applying a liquid to the absorbent layer; and

a means for separating said web into individual applicators or wipes.

20. The apparatus of claim 19 further comprising a means for folding the web along a center axis; and a means for sealing the web in a peelable seal in the dimensions of an individual applicator or wipe.

21. The apparatus of claim 19 or claim 20 further comprising a means for providing a handle means for said applicator or wipe.

22. The apparatus of claim 21 wherein the means for providing a handle means comprises a means for forming a pleat or gusset defining a folded flap in said layer of liquid impermeable material and a means for adhering the ends of the flap to the edges of said applicator or wipe.

23. The apparatus of claim 21 wherein the means for providing a handle means comprises a means for attaching an elongated strip to said layer of liquid impermeable material at opposite end portions of said strip with the medial portion thereof being unattached so that the medial portion of said strip forms a loop.