MXPA06014244A - Apertured tissue products - Google Patents

Abstract

The fluid intake rate of a tissue product having at least one hydrophobic exterior layer can be increased significantly by the addition of apertures through the hydrophobic exterior layer to the tissue product's hydrophilic interior layer. The apertures allow for fluid to be absorbed by the hydrophilic interior layer, while leaving the hydrophobic exterior layer dry to the touch. The size, number and spacing of the apertures can be controlled to manage the absorbent properties of the tissue product. In one embodiment, a three-ply tissue product has two exterior hydrophobic plies each having a plurality of apertures extending from the surface of both exterior plies through the plies to a hydrophilic interior ply.

Description

PERFORATED TISSUE PRODUCTS BACKGROUND Formulas containing polysiloxanes have been applied topically to tissue products in order to increase the softness of the product. In particular, adding silicon compositions to a facial tissue can impart improved softness to the tissue while maintaining the strength of the tissue. For example, tissue treated with polysiloxane are described in U.S. Patent Nos. 4,950,545; 5,227,242; 5,558,873; 6,054,020; 6,231,719; and 6, 432.270. A variety of substituted and unsubstituted polysiloxanes can be used.

Even though polysiloxanes are exceptionally good at improving softness, there may be disadvantages in their use. Polysiloxanes are generally hydrophobic meaning that they tend to repel water. Tissue products treated with polysiloxanes may be less absorbent than tissue products that do not contain polysiloxane. The absorbency of the tissue can also be reduced by the use of aminofunctional polysiloxanes, which tend to be more hydrophobic in nature. The increased hydrophobicity in a paper product, such as a tissue, can adversely impact the ability of the paper product to absorb liquids. Hydrophobic agents can also prevent bath tissue from becoming rapidly saturated and disintegrating or dispersing when disposed of in a toilet creating problems when the tissue is discarded by water.

Increasing the hydrophobicity of a paper product can provide several advantages. By making the paper tissue hydrophobic, the properties of the fluid transfer of the tissue can be improved. For example, the fluids absorbed by the tissue can remain inside the tissue paper and not be transferred through another side to wet the person's hands while using the tissue. Other methods to increase the barrier properties of the tissue, such as adding sizing agents to the tissue product, can be used.

In order to increase the absorbency of the tissue, the hydrophobic additives can be topically applied in discrete locations on a tissue product leaving relatively large untreated areas of the product such that less than about 50 percent of the surface of the product is covered. with the additive. The discrete location of the additive on the tissue product can provide regions of hydrophobicity and hydrophilicity. The discrete location may require a majority of the tissue surface that does not contain the additive. As a result, reduced product benefits, such as softness, are realized in relation to a product that has a high level of surface coverage. In addition to reduced benefits of smoothness, such products may not achieve the desired balance of rapid initial take and increased transfer time. U.S. Patent Application No. 10 / 289,557, entitled Soft Tissue Hydrophilic Tissue Products Containing Polysiloxane and Having Unique Absorbing Properties, filed on November 6, 2002, and herein incorporated by reference, describes the application of a surfactant in a patterned arrangement to improve the absorbent properties of a hydrophobic tissue product to balance the transfer and the absorbent rate.

As can be seen, there is a current need to develop tissue products that have good hand protection properties, however, face criteria for the absorbency generally requested in dry tissue products. There is also a need to manufacture these products with currently available technologies that introduce a minimum incremental cost to the product.

SYNTHESIS It has now been found that the rate of fluid intake of a tissue product having at least one hydrophobic outer layer can be significantly increased by the addition of perforations through the hydrophobic outer layer to the hydrophilic inner layer of the tissue product. The perforations allow the fluid to be absorbed by the hydrophilic inner layer, while leaving the hydrophobic outer layer dry to the touch. The size, number and spacing of the perforations can be controlled to administer the absorbent properties of the tissue product.

In one aspect, the invention resides in a flexible, thin, soft absorbent tissue, or cleaning cloth product having a rapid fluid intake however having delayed moisture penetration. In another aspect, the invention resides in a flexible, soft, thin absorbent tissue, or a cleaning cloth product structure comprising two hydrophobic perforated outer layers and a hydrophilic inner layer. In yet another aspect, the invention resides in a flexible, thin multi-stratum tissue product or a cleansing cloth product comprising three or more layers wherein the two outer layers comprise perforated hydrophobic layers that are adjacent to an inner stratum or stratum. which are hydrophilic. In another aspect, the invention resides in a flexible, thin, soft absorbent tissue or a cleaning cloth product comprising two hydrophobic perforated outer layers treated with polysiloxane and a hydrophilic inner layer. In yet another aspect, the product comprises mainly cellulose-based fibers.

BRIEF DESCRIPTION OF THE DRAWINGS The above aspects and other features, aspects, and advantages of the present invention will be better understood with respect to the following description, appended claims, and accompanying drawings, wherein: Figure 1 illustrates a tissue product of three strata Figure 2 illustrates a tissue product of three strata Figure 3 illustrates a tissue product of five strata Figure 4 illustrates a tissue product of two strata Figure 5 illustrates a tissue product of two strata Figure 6 illustrates a product of a single stratum.

Figure 7 illustrates a tissue product of a single stratum.

Figure 8 illustrates a tissue product of three strata.

Figure 9 is a schematic representation of an apparatus used to measure the Humidification Time Across and the Humidification Area.

Figure 10 is a plan view of the sample cover illustrated in Figure 9.

The repeated use of the reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the invention.

DEFINITIONS As used here, the forms of the words "understand", "have", and "include" are legally equivalent and open. Therefore, additional elements not mentioned, functions, steps or limitations can be presented in addition to the aforementioned elements, functions, steps or limitations.

As used herein, "hydrophobic layer" means that a layer of tissue repels water. A "layer" as used herein may be one or more layers of a single stratum and multiple layer tissue product, an entire stratum of a multiple layer tissue product, or one or more layers of any stratum within a layer. Multilayer tissue product. The hydrophobicity of the layer can be determined by the contact angle of a drop of water placed on a hydrophobic layer. An adequate test to measure the contact angle is the Standard Test Method D5725-99 of the American Society for Testing and Materials (ASTM) for Wetting and Surface Absorbency of Sheet Materials Using an Automated Contact Angle Tester. The hydrophobic layers of the present invention will exhibit contact angles of about 80 degrees or greater, more specifically about 85 degrees or greater, and even more specifically about 88 degrees or greater. Due to the absorbent nature of the tissue products, it can be difficult to measure the contact angle of the hydrophobic layer. For example, openings through the tissue layer can prevent measurement of the contact angle. As such, the measurement of the contact angle may need to be made on identical layers of tissue without the openings. The specific degree of hydrophobicity of the layer can vary as long as the product has a high rate of fluid intake while having a low tendency for the transfer or migration of fluid from one side of the product to the other side.

As used herein, the "hydrophilic layer" is any layer that is not a hydrophobic layer.

As used herein, "handover" refers to the time it takes for a liquid to pass from one side of a tissue to the other side. The handover can be measured using the Hercule Size Test as described in the Test Methods section.

As used herein, "tissue" refers to a substrate having one or more strata for cleaning solid surfaces and human skin or hair containing mainly cellulose fibers comprising at least a majority of the fibers present. The tissue of the present invention may comprise between about 80 percent to about 100 percent by weight of cellulose fibers, more specifically between about 85 percent to about 100 percent by weight of cellulose fibers, and even more specifically from about 90 percent to about 100 percent by weight of cellulose fibers based on the total dry weight of the fabric such as from about 95 weight percent to about 99.8 weight percent of cellulose fibers based on the total dry weight of the tissue sheet. The tissue sheets are relatively thin substrates having a low density that are considered microscopically planar even though the engraving may introduce height variations in the Z direction within the tissue sheet.

DETAILED DESCRIPTION It should be understood to one skilled in the art that the present disclosure is a description of exemplary embodiments only and is not intended as limiting the broad aspects of the present invention, the broad aspects of which are incorporated in the exemplary construction.

The tissue products can be differentiated from other paper products in terms of their volume. The volume of the tissue products of the present invention can be calculated as the caliper quotient (as tested in the later definition), expressed in microns, divided by the basis weight, expressed in grams per square meter. The resulting volume is expressed as cubic centimeters per gram. Writing papers, newsprint and other papers have greater strength, stiffness and density (low volume) compared to the tissue products of the present invention which tend to have much higher gauges for a given basis weight. The tissue products of the present invention have a volume that can range from about 2 cubic centimeters per gram to about 20 cubic centimeters per gram, more specifically from about 3 cubic centimeters per gram to about 20 cubic centimeters per gram. cubic centimeters per gram, even more specifically between about 4 cubic centimeters per gram to about 18 cubic centimeters per gram.

The tissue products of the present invention can be made by any suitable manufacturing process.

For example, suitable processes may include wet pressed creped tissue, air dried continuous tissue (TAD), uncreped tissue continuously dried by air (UCTAD), tissue placed by air, or hydroentangled cellulose products may be used. By mainly comprising cellulose fibers, the tissue products of the present invention are more prone to waste operations when re-pulping.

Scrap when re-pulping refers to a process used in the production of tissue and paper products. During the production of tissue and paper products, significant amounts of waste material can accumulate. This waste product, also known as waste, is generated from products that do not fall within the manufacturer's specifications or from the excess tissue that remains after the finished product is completed. Since the waste is essentially unused raw material, a process to recycle it for future use eliminates the inefficient disposal of an invaluable source of paper fibers. High amounts of non-cellulose solid materials, such as thermoplastic resins, synthetic fibers, non-cellulose films, and the like, significantly impede the ability of the waste material to be reused in the tissue or paper process and thereby increase the total cost of manufacturing the product. Therefore, there is an advantage for products comprising mainly cellulose fibers.

A wide variety of natural and synthetic cellulose fibers are suitable for use in the tissue, layer and layer products of the present invention. The pulp fibers may include fibers formed by a variety of pulping processes, such as kraft pulp, sulfite pulp, thermomechanical pulp, etc. In addition, the pulp fibers may consist of any pulp of high average fiber length, pulp of low average fiber length, or mixtures thereof.

An example of suitable high average length cellulose pulp fibers includes softwood fibers. The soft wood pulp fibers are derived from coniferous trees and include pulp fibers such as, but not limited to, soft northern wood, soft southern wood, redwood, red cedar, fir, pine (for example, southern pines). ), red spruce (for example, black spruce), combinations thereof, and the like. Northern softwood kraft pulp fibers can be used in the present invention. An example of commercially available northern wood kraft pulp fibers suitable for use in the present invention include those available from Kimberly-Clark Corporation, located in Neenah, Wisconsin, under the trademark designation of "Longlac-19".

Another example of suitable low average length cellulose pulp fibers are the so-called hardwood pulp fibers. The hardwood pulp fibers are derived from deciduous trees and include pulp fibers such as, but not limited to, eucalyptus, maple, birch, poplar, and the like. In certain instances, the eucalyptus pulp fibers may be particularly desired to increase the softness of the tissue sheet. Eucalyptus pulp fibers can also improve brilliance, increase opacity, and change the pore structure of the tissue sheet to increase its transmission capacity. In addition, if desired, secondary cellulose pulp fibers obtained from recycled materials can be used, such as fiber pulp from sources such as, for example, newsprint, recycled cardboard, and office waste.

Examples of other synthetic and natural cellulose fibers that can be used in the products of the present invention include, but are not limited to, cotton, rayon, lyocell, and the like.

Referring now to Figure 1, a multi-layer tissue product 30 is illustrated. The multi-layer tissue product has three distinct layers, including a hydrophobic upper outer layer 20, a hydrophobic lower outer layer 22, and an inner layer. hydrophilic 24. In this instance, the layers comprise of individual strata where the entire stratum is either hydrophobic or hydrophilic.

The hydrophilic inner layer 24 of the three layer product can be a high volume, low density material. The volume of the layer 24 can be in the range of between about 2 cubic centimeters per gram to about 20 cubic centimeters per gram, more specifically between about 3 cubic centimeters per gram to about 20 cubic centimeters per gram, yet more specifically between about 4 cubic centimeters per gram to about 18 cubic centimeters per gram. The hydrophilic inner layer 24 may have a specific absorbent capacity expressed as degrees of water absorbed per gram of fiber of about 5 grams per gram or greater, of about 7 grams per gram or greater, of between about 6 grams per gram to about 18 grams per gram, or between about 7 grams per gram to about 16 grams per gram. In one embodiment, the hydrophilic inner layer 24 may be a tissue product dried in air continuously (TAD) optionally containing a wet strength resin. The tissue dried in continuous form by air (TAD) flexible wet can be calendered. When moistened after fluid migration, the tissue dried continuously by air (TAD) can expand, providing additional absorbent capacity. This can help in keeping the water out of the outer surfaces of the tissue product and preventing the transfer or moisture through one side of the product to the other.

The upper and lower hydrophobic outer layers (20, 22) contain a plurality of openings 26 extending from an upper outer surface 21 and a lower outer surface 23 through both outer layers such that the fluids applied to the outer layers They migrate through the openings within the hydrophilic inner layer 24. Because the outer layers are hydrophobic and have lower free surface energy than the inner layer, there is little tendency for the fluid to wet the non-perforated regions 28 of the layers. outer layers keeping dry even absorbing significant amounts of fluid in a very short period of time.

The hydrophobic outer layers (20,22) have openings or holes extending from the outer surfaces (21,23) which are in fluid communication with the hydrophilic inner layer 24, such as extending through at least the thickness of the hydrophobic layer or layer. For example, the entire outer stratum does not need to be hydrophobic. The outer surface layer may be hydrophobic and the openings may extend only through the hydrophobic layer but not the entire stratum to the adjacent hydrophilic inner layer within the same stratum. In another embodiment, the openings may extend throughout the entire stratum regardless of whether the hydrophobic outer surface layer comprises the entire stratum or only one layer of the stratum.

The openings 26 can be dimensioned such that water or other fluids can not pass directly through the layer or the stratum when they are in contact with another layer or absorbent layer. Without wanting to be tied to a theory, depending on the size of the openings, it is believed that when the upper and lower hydrophobic layers (20, 22) are removed and a drop of water is placed on the outer surface of the hydrophobic layer, the drop of Water will remain on the surface and will not pass through the openings on the other side. The surface tension of the water creates a meniscus in the opening of the opening. Because there is sufficient surface tension present in the fluid, the fluid does not drip through the openings but instead remains on the surface. However, when the upper and lower hydrophobic layers (20,22) come into contact with the hydrophilic inner layer 24, the fluid in the meniscus region of the opening can contact the hydrophilic inner layer, transmitting the fluid in that layer. Capillary forces draw water from the surfaces of the outer strata through the openings and inside the hydrophilic inner layer. Once moisture is absorbed in the hydrophilic layer, water or fluid has a limited tendency to move from the hydrophilic layer through the openings to the hydrophobic outer layer facing opposite. The capillary action tends to move fluids from the outer surfaces through the openings in the absorbent hydrophilic layer while restricting the flow in the opposite direction. Therefore, the absorbent structures can be developed that keep the hands well protected, however they have excellent absorption properties both of an absorbent intake rate and an absorbent capacity.

In tissue products, the hydrophobic layer or layers may have a Wet Time (WOT) of between about 45 seconds or greater, about 60 seconds or greater, about 90 seconds or greater, or about 120 seconds. seconds or greater to around 600 seconds. While the wetting time of the hydrophobic strata can be very high, the rate of fluid intake in the central layer is very fast, due to the presence of the openings in the outer layers. This intake rate can be measured by the Automatic Gravimetric Absorbance Test (AGAT). The Automatic Gravimetric Absorbency Test (AGAT) is a test that generally measures the initial absorbency of a tissue product. The apparatus and the test are well known in the art and are described in the patent of the United States of America number 4, 357,827, incorporated herein by reference. The values of the Automatic Gravimetric Absorbentness Test (AGAT) of the entire multi-stratum tissue product may be between about 0.7 seconds or greater, about 0.9 seconds or greater, or about 1.1 seconds or greater than about of 5 seconds.

Alternatively, the Water Drop Test can be used to determine the intake rate. The Water Drop Time, as defined in the Test Methods section, of the entire tissue product may be from around., From 0 seconds to about 10 seconds, from about 0 seconds to about 7 seconds, or between about 0 seconds to about 4 seconds.

The absorbency of the hydrophilic inner layer 24 can be measured by the Moisture Area Test. The Moisture Area Test, as defined in the Test Methods section, refers to the area of the absorbent layer that is moistened before completing the complete wetting of the tissue product. The test is described in U.S. Patent No. 6,054,020, which is incorporated herein by reference. The tissue products of the present invention may have a Wet Area of about 2 square inches or greater. More specifically, the Wetting Area may be between about 3 square inches or greater, more specifically about 4 square inches or greater, to about 8 square inches after 20 seconds or less. The Moisture Time as measured by the Moisture Area Test may be between about 20 seconds or longer, about 30 seconds or longer, about 45 seconds or greater than about 60 seconds.

The size and frequency of the openings through the hydrophobic layer or layer can be varied to achieve specific product attributes. If the openings are very large, water can pass back through the wet surface or completely through the tissue product to the other side. If the openings are too small or insufficient in their frequency across the surface of the tissue product, the fluids will be absorbed with insufficient velocity to make the product useful as an absorbent tissue. When the tissue product is used as a cleaning implement, the increased hydraulic pressure applied by the cleaning process can increase the similarity that the fluids will penetrate the openings and be absorbed by the hydrophilic layer. Therefore, fewer and smaller openings can be used. Less apertures of smaller sizes can leave the appearance of the tissue product visually indiscernible from a non-perforated tissue product. The appearance of many openings or openings of a large size may result in a negative consumer perception that the tissue product is unsuitable for specific jobs commonly performed by non-perforated tissue products. For example, tissue products intended for nose care instead of cleaning and drying surfaces.

The size and number of openings in the hydrophobic layer is not critical to that placed on the invention as long as the fluid intake and transfer requirements are met. In general, apertures will be present at a frequency from about 3 apertures per linear inch to about 80 apertures per linear inch, such as from about 5 apertures per linear inch to about 600 apertures per linear inch, and even more specifically from about 10 openings per linear inch to about 400 openings per linear inch when measured in any direction of the sheet. The angle of the line used to measure the spacing of the openings on the product should be selected to give the maximum number of possible openings. The area of the openings can be in the range of between about 0.0002 square millimeters to about 8 square millimeters, more specifically between about 0.0004 square millimeters to about 5 square millimeters, and even more specifically of between about 0.0008 millimeters square to about 3 square millimeters.

The openings can be aligned with the openings on the opposite side of the product, they can slide from the openings on the opposite side of the product or they can randomly move and align with the openings on the opposite side of the product. In a specific embodiment, the openings on one side of the product are completely slid from the openings on the opposite side of the product. The displacement of the openings is advantageous in minimizing reflux where moisture in the product is expressed through the openings on the opposite side of the product via the pressure applied to a surface of the product. The displacement of the openings can also be advantageous in maintaining the tensile strength of the product and in reducing the formation of weak areas where the product can tear or break.

With reference now to Figure 2, the openings 26 may also have a three-dimensional shape where the size of the aperture varies as it extends from the hydrophobic layer (20,22) to the hydrophilic layer 24. In one embodiment, the apertures may be thinned in such a way that the size of the the opening to the outer surface of the hydrophobic layer is greater than the size of the opening where it contacts the hydrophilic layer. In another embodiment, the apertures can be thinned in an opposite manner in such a way that the size of the opening in the outer surface of the hydrophobic layer is smaller than the size of the aperture where the hydrophilic layer contacts. Preferably, the size of the opening is equal to or greater on the outer surface (21,23) of the hydrophilic layer than the size of the opening where the hydrophilic layer contacts. Variations in the thinning of the opening can help facilitate the flow of the liquid in the hydrophilic layers and minimize the wetting through the opposite side or surface.

The openings through the hydrophobic layer or layer can be made by a variety of methods. The perforated etching of the layer can be used in such a way that during engraving, the penetration of the layer is thus achieved by creating a physical perforation through the hydrophobic layer. The perforated engraving can be made either on the individual layers or layers, or especially the multi-layer tissue product. Other methods to form the openings include: perforated by bolt, struck by matrix, matrix stamping, water knives cutting the desired holes in the fabric, vacuum-assisted perforation where a high vacuum is applied to one side of the wet tissue as it is supported by a porous surface, laser cutters, needle punched and the like. In another embodiment, the openings can be made on the tissue machine as described in United States Patent No. 3,881,987, entitled "Method for Forming Perforated Fibrous Fabrics", which was granted to Benz on May 6, 1975.

Referring now to Figure 3, another multi-layer tissue product 30 having five different layers is illustrated. In the illustrated embodiment, the upper and lower hydrophobic outer layers (20,22) comprise hydrophobic layers that are perforated. Adjacent to each outer layer is a hydrophilic inner layer 24 comprising a hydrophilic layer. Between two hydrophilic inner layers is an inner hydrophobic layer 32. The inner hydrophobic layer comprises another hydrophobic layer having a plurality of openings 26 extending through the inner hydrophobic stratum. Such a tissue product may be useful for applications where a highly absorbent capacity and significantly longer transfer times are required.

Additional incorporations of multiple strata can be designed. For example, Figures 4 and 5 illustrate incorporations of two layers. With reference to Figure 4, an incorporation of two layers using tissue layers placed in two layers is illustrated. The single layer stratum tissue product 34 that forms each stratum is illustrated in Figure 6 and described hereinafter. The tissue products of a single stratum placed in two layers 34 are placed in a face-to-face relationship such that the perforated hydrophobic layers form the upper and lower outer layers (21 and 23) of the two-layer tissue product. In this embodiment, the hydrophobic layer forms only a part of the thickness of each stratum, and an inner hydrophilic layer 24 forms the remaining part of each stratum.

The openings 26 can extend only through the thickness of the hydrophobic layer, through the thickness of the hydrophobic layer and within the hydrophilic layer, across the entire thickness of each stratum, or through the entire thickness of the product of two. strata. The openings can be displaced or aligned with the openings on the opposite surface. Preferably, the openings do not extend through the entire thickness of the product of two layers. In one embodiment, the openings extend only through the depth of the hydrophobic layer of each stratum. The openings can be introduced either before or after the placement step in strata producing the product of two layers.

An alternative incorporation of two layers is illustrated in Figure 5. The single-layer tissue products placed in two layers 34 are placed in a face-to-face relationship such that one of the perforated hydrophobic layers forms a superior hydrophobic outer layer. 20 while the other side of the tissue product comprises a hydrophilic outer layer 36. The other hydrophobic layer of a stratum forms an inner hydrophobic stratum 32 having a plurality of openings 26. In this embodiment, the hydrophobic layer forms only a part of the hydrophobic layer. thickness of each stratum, and a hydrophilic layer forms the remaining part of each stratum.

The openings 26 can extend only through the thickness of the hydrophobic layer, through the thickness of the hydrophobic layer and within the hydrophilic layer, across the entire thickness of each stratum, or through the entire thickness of the product of two. strata. The openings can be displaced or aligned with the openings on the opposite surface. Preferably, the openings do not extend through the entire thickness of the product of two layers. In one embodiment, the openings extend only through the depth of the hydrophobic layer of each stratum. The openings may be introduced either before or after the layer placement step producing the product of two strata.

Possible applications of this multi-layer tissue product can be a tissue product where one side acts as a delay membrane when contacting the liquid. The water that contacts the side of the perforated hydrophobic outer layer can slowly migrate to another hydrophilic outer surface of the stratum. A reactive water component can be added to the hydrophilic outer layer 36 or placed adjacent to its surface. The water conduit to layer 36 may be delayed, and then react with the reactive component to produce the desired effect.

In an alternative, instead of using two strata of a single-layer tissue product placed in layers, the multi-layer tissue products of Figures 4 and 5 can be made of four separate strata having the desired hydrophobic or hydrophilic property. . In the various multi-layer tissue products, the perforated hydrophobic layer or layer is adjacent to at least one hydrophilic layer or layer. By adjusting the number of layers or strata and the hydrophobic or hydrophilic properties of the layers or strata it is possible to construct specific product properties such as intake rate, absorbency, and transfer as desired for the moisture delivery of the tissue product.

Referring now to Figure 6, an incorporation of a single stratum is illustrated. The single stratum 34 tissue product has been fabricated to form an upper hydrophobic outer layer 20 on one of the tissue surfaces adjacent to the hydrophilic inner layer 24. The hydrophobic layer can be created by making a tissue from a single stratum placed in layers as is known in the art and using polysiloxane-treated pulp for the hydrophobic layer as described in U.S. Patent No. 6,582,560, entitled "Method for Using Water Insoluble Chemical Admixtures with Pulp and Products Made by the called Method that was granted on June 24, 2003 to Runge and others, and which is incorporated herein by reference. Alternatively, the hydrophobic layer can be made by the addition of a suitable hydrophobic chemical to one of the supply jets forming one of the outer layers, or chemically treated to a mixed tissue product or placed in layers by adding a hydrophobic chemical to a of the exterior surfaces. For example, the hydrophobic film forming compositions can be used to form the hydrophobic layer and the compositions can be maintained mainly on the outer surfaces of the product of tissue with minimal penetration in the Z direction. Tissue machines that have the ability to produce fabrics in layers having the purity of a good layer are useful for making the incorporation of a single stratum. The use of fibers previously treated with a hydrophobic additive can be advantageous over the creation of the hydrophobic layer after forming and drying the fabric where control of the migration of the hydrophobic additive into the single-layer tissue product may be more difficult.

The upper hydrophobic outer layer 20 occupies only a part of the total thickness of the tissue product of a single stratum. In several embodiments, the thickness of the upper hydrophobic outer layer may comprise about 40 percent or less of the thickness of the stratum, of about 30 percent or less of the thickness of the stratum, of about 20 percent or less of the thickness of the layer. stratum, from about 5 percent to about 40 percent of the total thickness of the stratum, or between about 10 percent to about 30 percent of the total thickness of the stratum. The thickness of the upper hydrophobic outer layer is controlled to ensure adequate absorbent capacity to remain in the tissue of a single stratum. The remaining part of the tissue product of a single stratum comprises the hydrophilic inner layer 24, which is substantially or completely free of the hydrophobic additive.

A plurality of openings 26 extend from the surface of the upper hydrophobic outer layer in fluid communication with the hydrophilic layer such as through at least the depth of the hydrophobic layer to the hydrophilic inner layer 24. The openings can penetrate the entire Thickness of single-layer tissue product; however, in a preferred embodiment, the openings do not penetrate the entire thickness of the tissue product of a single stratum. The openings may extend partially into the hydrophilic inner layer without fully extending through the tissue product of a single stratum or the openings may terminate at approximately the interconnection between the hydrophobic and hydrophilic layer. The single stratum tissue product of Figure 6 can be placed in layers along with other multilayer or single stratus tissues to form a multi-stratum tissue product. For example, the multiple layer tissue products illustrated in Figures 4 and 5.

Referring now to Figure 7, another tissue product of a single stratum is illustrated. The tissue product of a single stratum 34 has been manufactured in such a way that the upper and lower hydrophobic layers (20,22) comprise the upper and lower outer surfaces (21,23). The middle part of the tissue product of a single stratum comprises the inner hydrophilic layer 24. The hydrophobic layers can be created by making a tissue from a single stratum layer placed in layers as is known in the art using polysiloxane-treated pulp for the layers external, adding a suitable hydrophobic chemical to the supply jets that feed the outer layers of the main box placed in layers, or chemically treating a product placed in layers or mixed tissue by adding a hydrophobic chemical to both outer surfaces. For example, the hydrophobic film forming the compositions can be used to form the hydrophobic layer and the compositions can be maintained primarily on the outer surfaces of the tissue product with minimal penetration in the Z direction. The tissue machines have the ability to produce placed fabrics in layers that have a good layer purity that are useful to make the incorporation of a single stratum. The use of fibers previously treated with a hydrophobic additive may be advantageous over the creation of the hydrophobic layer after forming and drying the tissue where it may be more difficult to control the migration of the hydrophobic additive into the single-layer tissue product.

The upper and lower hydrophobic layers (20,22) occupy only a part of the total thickness of the stratum alone. In several embodiments, the thickness of each of the hydrophobic layers may comprise about 30 percent or less of the thickness of the stratum, of about 20 percent or less of the thickness of the stratum, of about 10 percent or less of the thickness of the stratum, between about 5 percent to about 30 percent of the stratum thickness, or between about 5 percent to about 25 percent of the total thickness of the stratum. The thicknesses of the hydrophobic layers are controlled to ensure that adequate absorbent capacity remains in the tissue of a single stratum. The remaining part of the tissue product of a single stratum comprises the hydrophilic inner layer 24, which is substantially or completely free of the hydrophobic additive.

A plurality of openings 26 extend from the surfaces of the upper and lower hydrophobic outer layers in fluid communication with the hydrophilic inner layer such as through at least the depth of the hydrophobic layers to the hydrophilic inner layer 24. The openings can penetrate the entire thickness of the tissue product of a single stratum; however, in a preferred embodiment, the openings do not penetrate the entire thickness of the tissue product of a single stratum. The openings may extend partially into the hydrophilic inner layer without fully extending through the tissue product of a single stratum or the openings may end at approximately the connection between the hydrophobic and hydrophilic layer.

Tissue products of a single stratum having two layers of hydrophobic outer surface may have higher base weights and sizes than the incorporation of a single stratum illustrated in Figure 6, even when it is not necessary. The single-layer tissue product can be folded together with other multiple or single-layer tissues to form multi-layer tissue products. The single stratum tissue product illustrated in Figure 7 'is useful for applications where the delamination of individual strata within a multi-stratum tissue product may occur due to its intended use or for more economical tissue products where more high absorbent capacities are not required.

Referring now to Figure 8, another multi-layer tissue product is illustrated. The multi-stratum tissue product 30 comprises an upper and lower hydrophobic outer layer or layer (20,22) having a plurality of openings 26 and an inner hydrophilic layer or layer 24. In the embodiment illustrated, the hydrophobic layers comprise two outer layers and the hydrophilic layer comprises the middle stratum of the multilayer tissue product. Alternatively, the hydrophobic layers may comprise only one layer of the outer layers. Contained within the openings 26 are the hydrophilic fibers 36 that extend from the hydrophilic inner layer 24 that are pulled into the openings. The hydrophilic fibers 36 can provide a fluid conduit for rapid displacement in the hydrophilic inner layer of the tissue product.

As shown in Figure 8, the hydrophilic fibers 36 of the inner hydrophilic layer or layer are contained in the openings located in hydrophobic layers or layers. The hydrophilic fibers 36 may be below, in pairs with, or above the surface of the outer hydrophobic layer. In the illustrated embodiment, the hydrophilic fibers 36 extend above the upper outer surface 21 and are matched with the lower outer surface 23. Stitching techniques similar to the carding process can be used to manipulate the fibers in the apertures. Alternatively, needles having hooks or materials having hooks, such as the hook material of the hook and loop fasteners, can be used to pull the fibers into the openings with the pull while also creating the openings as the hooks or needles are pushed into the tissue product. The fibers can be cut to make them uniform with the outer surface if desired.

In the various single-stratum or multi-stratus tissue products of the invention, each stratum is relatively thin. The thinner caliber ensures that single or multi-layer tissue products have enough coverage and flexibility to act as a cleaning cloth. Other products that may have perforated layers, such as diapers or sanitary napkins, are generally unsuitable for use as a cleaning cloth or a cleaning sheet because of their stiffness and large thicknesses. The size of each stratum can be between about 0 microns to about 500 microns or less, such as about 400 microns or less, about 300 microns or less, or about 90 microns or less. Preferably, the multi-layer tissue products of the present invention have a total caliper for all strata of about 600 microns or less, of about 500 microns or less, or about 400 microns or less.

The "caliber" as used here, is the thickness of a single stratum or the product of multiple strata and can either be measured as the thickness of a single sheet or as the thickness of a stack of ten sheets and divided by the thickness of the sheets. Ten sheets by ten, where each sheet inside the stack is placed with the same side up. The caliber is expressed in microns. It is measured in accordance with the test methods of the Technical Association of the Pulp and Paper Industry (TAPPI) T402"Standard Conditioning and Testing Environment for Paper, Cardboard, Hand Sheets Pulp, and Related Products", and T411 om-89"Thickness (gauge) of Paper, Cardboard and Combined Cardboard", optionally with Note 3 for stacked sheets. The micrometer used to perform the T411 om-89 test is a Volume Micrometer (TMI Model 49-72-00, from Amityville, New York) or its equivalent, which has an anvil diameter of 4 1/16 of an inch (103.2). millimeters) and an anvil pressure of 220 grams per square inch (3.3 kilo Pascal).

In a specific embodiment of the multi-layer tissue product, it may be advantageous to use layers having different calibers with the hydrophobic perforated outer layer or layers having a lower caliber than the hydrophilic inner layer or layers. The necessary absorbent capacity can be provided by the thicker hydrophilic layer while the desired prevention of fluid transfer can be provided by the thinnest perforated hydrophobic layers.

The completely dry basis weight of the tissue products can be in the range of between about 8 grams per square meter to about 120 grams per square meter, more specifically between about 10 grams per square meter to about 100 grams per square meter. square meter, and even more specifically between about 20 grams per square meter to about 80 grams per square meter, such as between about 25 grams per square meter to about 60 grams per square meter. The completely dry basis weight of any individual stratum can be in the range of about 4 grams per square meter to about 100 grams per square meter, more specifically between about 6 grams per square meter to about 80 grams per meter square and even more specifically between about 8 grams per square meter to around 70 grams per square meter.

For multi-layered products of the present invention, it may sometimes be advantageous to use different base weights for the various strata. In a specific embodiment of the three layer or three layer product of the present invention, the basis weight of the hydrophilic inner layer is greater than the basis weight of the upper and lower hydrophobic outer layers. In the various embodiments, the basis weight of the hydrophilic inner layer may be from about 10 percent to about 500 percent greater than the basis weight of the hydrophobic outer layers, or from about 25 percent to about 300 percent greater than the basis weight of the hydrophobic outer layers, or from about 30 percent to about 200 percent greater than the basis weight of the hydrophobic outer layers.

The tensile strength of the tissue products of the present invention can be adjusted in such a way that the tensile strength is sufficient for the intended application. In general, the tissue products of the present invention will have a geometric average tensile strength (GMT) of between about 300 grams by 3 inches to about 3,000 grams by 3 inches, or from between about 500 grams by 3 inches to about 2,000 grams by 3 inches, or from between about 650 grams by 3 inches to around 1500 grams per 3 inches. Since the perforation process of the stratum or layer can reduce the tensile strength of that stratum or layer, it may be advantageous to use a higher strength layer or layer and then perforate that stratum or layer in such a way that the tensile strength per unit of basis weight of the stratum or perforated hydrophobic layer, after perforation, approximates the tensile strength per unit of basis weight of the hydrophilic layer or central layer.

The transfer resistance of the tissue product can be measured by the Hercules Size Test (HST). The tissue products of the present invention may have Hercule Size Test values of between about 10 seconds or greater, about 15 seconds or greater, about 25 seconds or greater, about 35 seconds or greater than around 300 seconds.

The single-layer and multi-extract tissue products of the present invention are useful for facial, bath, napkin and paper towel products. The tissue products can be useful in other applications where specific attributes are essential for the function of the product. For example, tissue products can be used in healthcare settings to clean potentially biohazardous fluids or other fluids, provide protection beyond gloves. The fluid trapped in the hydrophilic layer is less prone to drip through the tissue product and contaminate other areas. In a similar way, tissue products can find use in chemical laboratories and industrial environments for improved protection against contact with hazardous materials. In multi-layer tissue products, the inner layers may contain agents against the virus or other ingredients to act on specific elements in the absorbed fluid, but still prevent the active agent from contacting the user.

The chemistry for making the hydrophobic layers or the complete hydrophobic layers can be done by any method known in the art. The hydrophobic layers or layers can be made by the use of sizing agents, polysiloxanes, hydrophobic acrylates, or any other material capable of imparting hydrophobicity to the product as is known in the art. Specifically in one embodiment, hydrophobicity can be created using standard cellulose sizing agents as described in U.S. Patent No. 6,027,611, entitled "Facial Tissue with Reduced Moisture Penetration", issued to McFarland et al., And incorporated herein. by reference. In yet another embodiment, hydrophobicity can be created using hydrophobic polysiloxanes. Such polysiloxanes are widely known in the art. The polysiloxanes are also useful in imparting surface smoothness to the product. The specific polysiloxanes particularly suitable for the present invention are the functional amino polysiloxanes. Such polysiloxanes will generally have the following structure: Where x and y are integers > 0. The mole ratio of x to (x + y) can be from about 0.005% to about 25%. The Rx-R9 moieties can independently be any functional organic group including Ci or higher alkyl groups, ethers, polyethers, imines, amides, or other functional groups including the alkyl and alkenyl analogs of such groups. The R 10 moiety is an amino functional moiety including but not limited to the primary amine, the secondary amine, the tertiary amines, the quaternary amines, the unsubstituted amides and the mixtures thereof. An exemplary R 10 moiety contains one amine group per constituent or two or more amine groups per substituent, separated by a linear or branched alkyl chain of C 1 or greater. In such specific incorporation, R7 and R8 are Ci or higher alkyl groups or mixtures thereof. In another embodiment R7 and R8 are methyl. Specific polysiloxanes suitable for the present invention include: DC 2-8220 manufactured and sold by Dow Corning, of Midland, Michigan and Y-14, 344 manufactured and sold by GE / OSi Corporation. The hydrophobic additive can be applied at any concentration to make the stratum or hydrophobic layer as defined. In particular, the polysiloxane concentration, if present, may be in the range of between about 0.2% by weight to about 5% by weight of the total dry fiber in the tissue product, specifically from about 0.3% to about 4% by weight of the total dry fiber, and more specifically from about 0.5% to about 2% by weight of the dry fiber. It may also be advantageous to use a sizing agent to generate some hydrophobic properties in conjunction with the polysiloxane to minimize the use of costly polysiloxanes.

EXAMPLES Example 1 Two tissue products of three layers were prepared having an upper and lower hydrophobic outer layer and a hydrophilic inner layer in the following manner. The two hydrophobic outer layers were prepared by penetrating the cellulose eucalyptus fibers with a hydrophobic amino functional polysiloxane (DC 2-8220 from Dow Corning, Midland, Michigan) at a level of 2.5% by weight of polysiloxane using the method described by Runge in the patent of the United States of America number 6,582,560. The hydrophobic moist-pressed creped single layer tissue product has a basis weight of about 12.5 grams per square meter and a single stratum gauge of 90 microns was prepared using the pulp fibers pretreated. The single-layer tissue product was a two-layer layer comprising 70% of fibers treated with eucalyptus silicone as one layer and 30% NSWK pulp as the other layer. The total silicone content in the product was approximately 1.75%.

A single stratum hydrophilic inner layer was made from a non-creped, air dried, single stratum hydrophilic tissue product having a complete dry basis weight of about 45 grams per square meter and a gauge of about 400 microns.

A tissue product of three strata having a total basis weight of about 60 grams per square meter was prepared by using the hydrophobic moist pressed tissue as the outer layers with the tissue dried through the non-creped inner air as the central stratum. The outer hydrophobic layers were oriented so that the layers containing the silicone-treated pulp formed the outer surfaces of the three-layer tissue product. The product of three non-perforated strata had a test time of water fall in excess of 3 minutes when tested.

Another three-layer tissue product was made by bolting the hydrophobic outer layers prior to placement on the side of the hydrophilic inner layer. The perforations had a diameter of about 0.5 millimeters and were spaced by approximately 2 millimeters apart in both directions X and Y. The three-layer tissue product had a total basis weight of about 60 grams per square meter using the pressed tissue wet hydrophobic perforated as the outer layers with the tissue dried through non-creped interior air as the central stratum. The perforated outer hydrophobic layers were oriented so that the layers containing the treated silicone pulp formed the outer surfaces of the three-layer tissue product. The perforated tissue product had a water drop test time of less than 1 second. A large area of the hydrophilic inner layer was wetted and there was no wetting on the opposite perforated hydrophobic layer nor was there any penetration of liquid to the surface below the tissue.

Example 2 The eucalyptus fibers were pulped for 30 minutes and placed in a retention box. Similarly, a mixture of 72% kraft from soft northern wood and 28% kraft from northern hardwood was pulped for 30 minutes and placed in a holding box. The mixtures of northern hardwood fiber / northern softwood and eucalyptus were then supplied to the individual supply boxes and a commercially available wet strength chemical was added (Kymene 557LX, from Hercules, Inc., of Wilmington, Delaware) in the amount of 0.82 pounds / ton of active solids by weight of total product and a sizing agent (Precis 3000, commercially available from Hercules Incorporated) was added at a rate of 1.75 pounds / ton of active solids by weight of total product.

The solutions were sent by a fan to a layered head box to form a three layer tissue product comprising 30% eucalyptus fibers in each outer layer and 40% NSWK / NHWK fibers in the inner layer. The suspension is deposited from the multi-layer headbox onto an Appleton Mills 2164A forming fabric and an Appleton Mills 5611-AmFlex 2 S press felt and drained to around a 12% consistency. The fabric was then transferred to the Yankee dryer through a pressure roller under vacuum. The pressure roller with vacuum covered in rubber also drains the wet fabric to approximately 42% consistency through mechanical pressing against the Yankee dryer at a clamping point pressure of 200 pounds per linear inch with a vacuum pressure of 5 inches against the press felt.

The fabric was then dried on the dryer Yankee heated with steam to a dry weight consistency greater than 96%. Prior to removing the fabric from the dryer with a creping doctor blade, the fabric temperature reached in excess of 180 ° F. An aqueous mixture of an adhesive was sprayed continuously onto the Yankee dryer through a spray bar. The creped tissue was then wound onto a core that runs at a speed approximately 30% slower than the Yankee dryer. The three-layer single layer tissue product is highly hydrophobic having a total wetting time in excess of 300 seconds. The contact angle was determined as being 90 °. The tissue product had a basis weight of 2.5 grams per square meter and a single layer size of 90 microns.

Another crepe single layer tissue product having a basis weight of 12.5 grams per square meter was prepared as indicated above with the exception that the sizing agent was not used. The three layer hydrophilic single stratum tissue product had a single stratum gauge of 110 microns, a specific absorbent capacity of about 9 grams / gram and a total wetting time of 3.4 seconds.

A three layer tissue product was made from the single stratum hydrophilic and hydrophobic tissue products. The perforations were created through a needle-etching process in the hydrophobic tissue layers. The perforations are approximately 0.5 millimeters in diameter and are spaced about 1.5 millimeters apart in the X and Y directions. The hydrophilic layer and the two hydrophobic perforated layers were then put together to form a three-layer tissue product with the perforated hydrophobic strata forming the two outer strata of the tissue product of three strata. The three-layer tissue product had a water drop test value of 3.5 seconds, a wet area in full form of 5 square inches and after 30 seconds (there was no wetting that passed through) and an HST value of 55 seconds .

TEST METHODS Geometric Mean Stress (GMT) The geometric mean tension (GMT) resistance test whose results are expressed as force-grams per 3 inches of sample width. The geometric mean stress is computed from the peak load values of the voltage curves in MD (machine direction) and CD (machine direction), which are obtained under laboratory conditions of 23.0 ° C ± 1.0 ° C, 50.0 ± 2.0% relative humidity, and after the tissue sheet had equilibrated to the test conditions for a period of not less than four hours. The test is conducted on a tension tester that maintains a constant rate of elongation, and the width of each tested specimen was 3 inches. The "jaw extension" or the distance between the jaws, sometimes referred to as the measurement length, can vary from about 2.0 inches (50.8 millimeters) to about 4.0 inches (100.6 millimeters). The crosshead speed is 10 inches per minute (254 millimeters per minute). A load cell or full scale load is chosen so that all peak load results fall between 10 and 90% of the full scale load. Such testing can be done on an Instron 1122 voltage chassis connected to a Sintech data acquisition and control system using IMAP software running on a "class 486" personal computer or equivalent system. This data system records at least 20 load and elongation points per second. A total of 10 specimens per sample for each address are tested. The average of the ten values of tension in the machine direction is determined and the average of the ten values of tension in the transverse direction is determined. The geometric average tension is calculated using the values of tension in the direction of the machine and in the average transversal direction of the following equation: GMT = (MD Tension * CD Tension) 1 2 Automatic Gravimetric Absorbance Test (AGAT) The automatic gravimetric absorbency tester (AGAT) is a test that generally measures the initial absorbency of the tissue product. The apparatus and the test are well known in the art and are described in U.S. Patent No. 4,357,827 entitled Gravimetric Absorbent Tester which was issued on November 9, 1982 to McConnell and which is incorporated herein by reference. . For the purposes of the present invention, six tissue products are tested together (6 strata for each single stratum product, 12 strata for a product of two strata and 18 strata for the product of three strata). All specimens were conditioned for the test by at least 4 hours at 23 +/- 1 ° C and 50 +/- 2% relative humidity before the test. During the test, the specimen was placed on a test cell that is in communication with a reserve reservoir. For three layer products, six tissue products are tested together to form a test specimen. (Three strata per product, 18 strata in total). A valve is then operated so that the liquid is free to flow from the container to the test cell. The sample being tested absorbs the liquid from the reservoir container. The amount of liquid taken by the test specimen is determined over a period of time. In particular, the automatic gravimetric absorbency test machine generates an absorption curve from 2.25 seconds to as long as desired. The result of the automatic gravimetric absorbance test is obtained by measuring the average inclination between 2.25 and 6.25 seconds. Ten test specimens are prepared for each tissue product tested and the average of the ten test specimens is reported as the automatic gravimetric absorbency test value of the tissue product.

Size Test Hercules The Hercules size test (HST) is a test that generally measures how long it takes for a liquid to travel through a tissue product. The Hercules size test is generally done according to the TAPPI method T 530 PM-89, Size Test for Ink Resistant Paper. The Hercules size test data was collected on a Hercules size test model tester using white and green calibration tiles and the black disk provided by the manufacturer. A 2% green naphthol N dye diluted with 1% distilled water was used as the dye. All materials are available from Hercules, Inc., of Wilmington, Delaware.

All specimens were conditioned for at least 4 hours at 23 +/- 1 ° C and at 50 +/- 2% relative humidity from the test. The test is sensitive to the temperature of the dye solution so that the dye solution must also be equilibrated at the controlled condition temperature for a minimum of 4 hours before the test. Six tissue products form a specimen for the test (18 layers for a tissue product of three strata, 6 strata for a single stratum product). The specimens are cut to an approximate dimension of 2.5 x 2.5 inches.

The instrument is standardized with white and green calibration tiles according to the manufacturer's instructions. The specimen is then placed in the sample holder with the outer surface of the strata facing outward. The specimen is then held in the specimen holder. The specimen holder is then placed in the retaining ring on top of the optical case. Using the black disk, the zero instrument is calibrated. The black disc is removed and 10 +/- 0.5 millimeters of the dye solution is dispensed into the tension ring and a time meter is started while the black disc is placed back on the specimen. The test time in seconds is recorded from the instrument.

Water Drop Test The water drop test measures the intake rate of the tissue product. The water drop test values are measured after first conditioning the tissue product to 23.0 ° C ± 1.0 ° C and 50.0% ± 2.0% relative humidity for a period of at least 4 hours. The conditioned test specimen is placed on a dry glass plate. The tissue product is tested as manufactured as a single layer or multiple layer tissue product. A single drop (100 microliters, 0.1 ± 0.01 milliliters) of distilled water (23.0 ° C ± 1.0 ° C) is stocked with an Eppendorf-style pipette placed slightly above the surface of the test specimen.

To determine the intake rate, the drop of water should be placed near the center of the test specimen. The drop of water is seen by the naked eye on a horizontal plane to the surface of the test specimen. A stopwatch is started immediately after the drop of water is dispensed on the test specimen. The time elapsed for the drop of water to be completely absorbed by the specimen, measured in seconds, is the value of the water drop test for the specimen. The water drop is completely absorbed when it completely disappears, that is, there is no visible vertical element of the remaining water drop. Yes after 3 minutes, the water drop has not been fully absorbed, the test stops and the water drop value is assigned to a value of 180 seconds. Ten (10) drops of water are placed at random on the surface of the test specimen by a sufficient distance so that the water is not absorbed by the water previously moistened. The test values for each drop are recorded and averaged. The average take time in seconds is recorded as the water drop test value.

Wet Transfer Time and Total Wet Area Referring to Figure 9, the method for determining the wet handover time and the total wet area will be described in more detail. The test is also fully described in U.S. Patent No. 6,065,420, entitled Soft Absorbent Tissue Products having a Delayed Moisture Penetration, issued to Goulet et al. And incorporated herein by reference. In general, the method involves placing a measured quantity of stained liquid on the upper surface of a tissue sample and measuring the time it takes for the liquid to pass through the sample to activate a moisture sensor placed on the bottom of the tissue. tissue. That time is the wet transfer time. Once the wet transfer time has been reached, the extent to which the dyed liquid will have been transmitted in the x-y direction of the tissue will be visible as a circular or elliptical spot. The area of the point is the complete wet area.

Figure 9 schematically illustrates the equipment set up to carry out the test procedure. A sensor 1 is shown which rests on a flat surface and is connected to a humidity light indicator 2. (The specific humidity sensor is a Cole-Parmer Liqui-Sense 77096-00 controller manufactured by Barnant Company, of Barrington, III., With a Cole-Parmer Liqui-Sense sensor 77095-00). The sensitivity of the humidity sensor is calibrated to respond to 0.2 milliliters of the test liquid (described below) according to the manufacturer's instructions. The tissue sample 3, which has been folded in half and placed on top of the moisture sensor, is secured with the two Lexan side weights 4 and 5 placed on both sides of the humidity sensor. Each side weight measures 3/4 inches by 1/4 inches in cross section and is 4 inches long. These weights are placed so that the folded tissue sample rests flat against the surface of the humidity sensor but is not under tension. On top of the sample is placed a 4 inch by 4 inch by 1/2 inch 6 Lexan sample cover as further illustrated in Figure 10. The sample cover has a conical hole 7 through the center measuring 3 / 8 inches in diameter on the top surface and 1/16 inches in diameter on the bottom surface. Because the thickness of the humidity sensor is slightly less than 1/4 inch in thickness of the side weights, the sample holder primarily rests on the lateral weights. The conical hole 7 is positioned to reside on at least one opening of the hydrophobic outer layer, stratum or surface.

Placed on top of the sample cover is a video camera 8 (JVC TK-1070U color video camera made in Japan by JVC or equivalent). The output of the video camera is connected to a video cassette recorder 9 (Panasonic AG-1 960 Proline distributed by Panasonic Industrial Company, of Secaucus, New Jersey or equivalent) and a color monitor 10 (Panasonic CT-1 381-Y color video monitor or equivalent). The video camera is placed on a tripod so that the humidity light indicator 2 is visible within the vision of the video camera.

The test liquid used to carry out the test is a Hercules-sized green tester dye, available from Hercules Incorporated, of Wilmington, Delaware. The test liquid has the following properties measured at 22 ° C: viscosity of 10 centipoise when measured using a Brookton Synchroelectric Brookfield viscometer with a No. 1 spindle at a speed of 50 revolutions per minute; a surface tension of 60.5 dynes per centimeter when measured using a duNouy ring tensiometer (from Fisher Scientific Surface Tensiometer 20); pH of 7.3; and a specific conduction of 18 micro Siemens per centimeter.

To carry out the test to determine the wet transfer time and the complete wet area, the video photo is adjusted so that the photo of the sample cover measures 6 inches by 6 inches on the video monitor. The LiquiSense controller unit is positioned so that the alarm light (humidity indicator light) can be clearly seen on the video camera. A sample of the tissue product to be tested is bent in half, placed on the moisture sensor, and secured with the side weights, and covered with the sample cover as shown and described previously. The video cassette recorder (VCR) starts. Using a micro-pipette, 0.5 milliliters of test liquid are placed in hole 5 of the sample cover and the time measurement of the test is started. When the humidity monitor alarm light is activated, the time in seconds is the wet transfer time for that sample. After that point the video cassette recorder is stopped. Using the video push and pause characteristics, the video image is adjusted to the frame where the alarm was activated, showing the size of the stain created by the stained test liquid. The area of the dye image on the video screen at that point in time, expressed in square inches is the complete wet area. Because the shape of the dye images is generally elliptical, the area can be easily determined by measuring the principal and minor axis of the ellipse and calculating the area. However, if greater precision is desired, it will be appreciated that it is also possible to calculate the area using more sophisticated image analysis techniques.

Full Wet Time As used herein, "full wetting time" is a measure of how quickly the tissue product absorbs water and reaches its absorbent capacity, expressed in seconds. In particular, the complete wetting time is determined by selecting and cutting twenty (20) samples of representative tissue product in squares measuring 63 millimeters by 63 millimeters (± 3 millimeters) after first conditioning the tissue product at 23.0 ° C. ± 1.0 ° C and 50. 0% ± 2.0% relative humidity for a period of at least 4 hours. The resulting twenty sample products are assembled into a test specimen pad by stacking the twenty individual samples one on top of the other while aligning their edges forming a specimen pad.

For products of multiple strata having different hydrophobic and hydrophilic layers, the complete wetting time of each stratum can be determined separately by separating the strata of the tissue products and. then test the specimen pads formed of layers taken from the same location within the multi-stratum tissue product. Therefore, one can determine the complete wetting time of an individual stratum of the complete multiple stratum product.

The specimen pad is then stapled together through each corner of the specimen pad just far enough from the edges to hold the staples, staples must be diagonally oriented through each corner and should not wrap around the edges of the specimen pad. test specimen With the sample tips down, the specimen pad is held horizontally, approximately 25 millimeters from the surface of a tray of distilled or deionized water at a temperature of 23 ° C ± 3 ° C. The tray should be large enough and be filled with water deep enough to initially float the specimen pad without touching the edges or bottom of the tray. The specimen pad is dropped flat on the surface of the water and the time for the specimen pad to completely saturate visually with the water is recorded. The time, measured to the nearest 0.1 seconds, is the wet wet time for the specimen pad. At least five (5) duplicate measurements were made by assembling a new specimen pad of the same tissue product material to give a reliable average. The reliable average is reported as the complete wetting time in seconds.

Other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. It is understood that the aspects of the various incorporations can be exchanged in whole or in part. All cited references, patents or patent applications in the above application for patent certificates are incorporated herein by reference in a consistent manner. In the case of inconsistencies or contradictions between the references incorporated and this request, the information presented in this application shall prevail. The present description given by way of example in order to allow one with an ordinary skill in the art to practice the claimed invention, should not be considered as limiting the scope of the invention, which is defined by the claims and all equivalents of the invention. the same.

Claims (25)

R E I V I N D I C A C I O N S

1. A tissue product, comprising: an upper hydrophobic outer layer having an upper outer surface, a hydrophilic inner layer; Y a plurality of openings extending from the upper outer surface in fluid communication with the hydrophilic inner layer.

2. The tissue product as claimed in clause 1, further characterized in that it comprises: a lower hydrophobic outer layer having a lower outer surface; Y a plurality of perforations extending from the lower outer surface in fluid communication with the hydrophilic inner layer.

3. The tissue product as claimed in clauses 1 or 2, characterized in that the tissue product comprises a single stratum having multiple layers.

4. The tissue product as claimed in clauses 1 or 2, characterized in that the tissue product comprises more than one stratum.

5. The tissue product as claimed in clause 4, characterized in that the upper hydrophobic outer layer, the inner hydrophilic layer, and the lower hydrophobic outer layer comprise a full thickness of a tissue layer.

6. The tissue product as claimed in clause 5, characterized in that the openings extend completely through the upper and lower hydrophobic outer layers.

7. The tissue product as claimed in clause 4, characterized in that the upper hydrophobic outer layer, the inner hydrophilic layer, and the lower hydrophobic outer layer comprise one or more layers of a tissue layer.

8. The tissue product as claimed in clause 4, further characterized by comprising: a hydrophobic inner layer; and a plurality of openings located in the hydrophobic inner layer extending at least through the hydrophobic inner layer.

9. The tissue product as claimed in clause 4, characterized in that the openings contain hydrophilic fibers pulled through the openings from the hydrophilic inner layer.

10. The tissue product as claimed in clauses 3 or 4, characterized in that the openings have a frequency and the frequency is between about 3 to about 800 openings per linear inch.

11. The tissue product as claimed in clauses 3 or 4, characterized in that the openings have an area and the area is between about 0.0001 square millimeters to about 8 square millimeters.

12. The tissue product as claimed in clauses 3 or 4, characterized in that the openings are tapered and the size of the openings is larger on the outer surfaces than the size of the openings near the hydrophilic layer.

13. The tissue product as claimed in clause 2, characterized in that the openings in the upper outer surface are offset relative to the openings in the lower outer surface.

14. The tissue product as claimed in clauses 3 or 4, characterized in that the total size of the tissue product is about 600 microns or less.

15. The tissue product as claimed in clauses 3 or 4, characterized in that the HST value for the tissue product is between about 10 seconds to about 300 seconds and a water drop time is between about 0 to around 10 seconds.

16. The tissue product as claimed in clauses 3 or 4, characterized in that the HST value for the tissue product is between about 25 seconds to about 300 seconds and a water drop time is between about 0 to around 7 seconds.

17. The tissue product as claimed in clauses 3 or 4, characterized in that the HST value for the tissue product is between about 10 seconds to about 300 seconds and an AGAT time is between about 0.7 to about of 5 seconds.

18. The tissue product as claimed in clauses 3 or 4, characterized in that the wet transfer time for the tissue is between about 20 seconds to about 60 seconds, a water drop time is between about 0 seconds to around 10 seconds, and the entire wet area is about 3 square inches or larger.

19. The tissue product as claimed in clause 1, characterized in that the hydrophobic outer layer comprises a polysiloxane.

20. The tissue product as claimed in clause 2, characterized in that both lower upper hydrophobic outer layers comprise a polysiloxane.

21. The tissue product as claimed in clauses 19 or 20, characterized in that the polysiloxane comprises an amino functional polysiloxane.

22. The tissue product as claimed in clauses 19 or 20, characterized in that the polysiloxane comprises an amount of between about 0.3% to about 4% by weight of the total dry fiber in the product.

23. The tissue product as claimed in clause 2, characterized in that it comprises a basis weight for each layer and the base weight of the hydrophilic inner layer is greater than the basis weight of the upper and lower hydrophobic outer layers.

24. The tissue product as claimed in clause 23, characterized in that the basis weight of the hydrophilic inner layer is about 25% to about 300% greater than that of the outer hydrophobic layers or layers.

25. The tissue product as claimed in clauses 1 or 2, characterized in that it comprises a tensile strength and tensile strength is between about 300 grams / 3 inches to about 3,000 grams / 3 inches. SUMMARIZES The rate of fluid intake of a tissue product having at least one hydrophobic outer layer can be significantly increased by the addition of perforations through the hydrophobic outer layer to the hydrophilic inner layer of the tissue product. The perforations allow the fluid to be absorbed by the hydrophilic inner layer, while allowing the hydrophobic outer layer to be dry to the touch. The size and number and spacing of the openings can be controlled to handle the absorbent properties of the tissue product. In one embodiment, a three-layer tissue product has two hydrophobic strata each having a plurality of perforations extending from the surface of both outer layers through the layers to a hydrophilic inner layer.