EP4719318A1

EP4719318A1 - High strength hydroentangled sheet containing non-wood fibers

Info

Publication number: EP4719318A1
Application number: EP24816541.7A
Authority: EP
Inventors: Thomas G. Shannon; David A. Moline; Bo Shi; Joseph K. Baker; Zhiying Yu
Original assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Current assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Priority date: 2023-05-31
Filing date: 2024-05-31
Publication date: 2026-04-08
Also published as: WO2024249815A1; MX2025013518A; CN121218962A; KR20260016506A; AU2024280731A1

Abstract

The present disclosure is generally directed to dry or pre-moistened wiper with high tensile strength characteristics. The sheet products are primarily made from non-wood pulp fibers, particularly Hesperaloe fibers.

Description

HIGH STRENGTH HYDROENTANGLED SHEET CONTAINING NON-WOOD FIBERS

CROSS-REFERENCE TO RELATED APPLICATION

The present application is related and has right of priority to U.S. Provisional Patent Application No. 63/505,142 filed on May 31 , 2023, which is incorporated by reference in its entireties for all purposes.

BACKGROUND

Domestic and industrial wipers are often used to absorb liquids and pick up debris. In some applications, the wipers are formed into a premoistened wiping product for the purposes of cleaning and/or disinfecting. In the past, many attempts have been made in order to produce non-cloth wiping products made from nonwoven fibers that are designed generally to be used and discarded. Such wipers should possess a good balance of properties, including good physical strength and abrasion resistance, to withstand the tearing, stretching, and abrading forces often applied during use.

In the past, many nonwoven wipers have been constructed from wood pulp fibers in combination with synthetic fibers, such as polyester fibers. For example, in the past, wood pulp fibers, such as softwood fibers, have been hydroentangled with synthetic polymer fibers in order to produce a resilient wiping product.

For example, in one embodiment, the wood pulp fibers have been combined with polymer synthetic fibers, such as polyester fibers, polypropylene fibers, and the like for increasing the strength of the web. Polymer synthetic fibers, however, are naturally hydrophobic and have poor absorbency. The wipers also require significant amounts of polymer, particularly fossil-based polymers, for constructing the wipers.

In an alternative embodiment, wood pulp fibers have been combined and hydroentangled with regenerated cellulose fibers, such as rayon fibers. Regenerated cellulose fibers are formed from wood pulps that have been purified, dissolved in the solvent, and then spun into fibers. Regenerated cellulose fibers have good absorbency and strength properties and provide softness to the web. Regenerated cellulose fibers, however, have an exorbitant cost and still create environmental concerns.

In fact, even the supply of wood pulp fibers, such as Northern softwood kraft fibers, is under significant pressure both economically and environmentally. These conditions have led to a dramatic increase in the cost of softwood pulp fibers and to a desire to minimize their use.

In view of the above, a need currently exists for nonwoven webs that can be produced with high strength properties while minimizing the amount of wood pulp fibers, synthetic fibers, and regenerated cellulose fibers. SUMMARY

The present disclosure is generally directed to nonwoven webs, particularly hydroentangled nonwoven webs that contain little to no wood pulp fibers. In fact, in one embodiment, the nonwoven web can be constructed so as to be wood pulp fiber free. Nonwoven webs made according to the present disclosure can, instead, be made from non-wood plant fibers that have relatively low coarseness properties. The non-wood plant fibers can be used alone or in combination with staple fibers for producing base sheets having excellent strength properties when either dry or wet. In one aspect, the amount of staple fibers can be minimized or even eliminated when producing the webs.

For example, in one embodiment, the present disclosure is directed to a sheet product comprising a base sheet containing non-wood pulp fibers in an amount of greater than 50% by weight, such as in an amount of greater than about 70% by weight, such as in an amount greater than about 80% by weight, such as in an amount greater than about 90% by weight, such as in an amount greater than about 95% by weight. In one embodiment, all of the fibers contained in the base sheet can comprise the non-wood pulp fibers. The non-wood pulp fibers can have a coarseness of less than about 10 mg/100 m (1 .0 dTex), such as less than about 8 mg/100 m (0.8 dTex), such as less than about 6 mg/100 m (0.6 dTex), such as less than about 5 mg/100 m (0.5 dTex), and can have an average fiber length of from about 1 .5 mm to about 3 mm. In one aspect, the non-wood fibers can be derived from one or more plants of the genus Hesperaloe. The fibers, for instance, can be derived from one or more of the following plants: Hesperaloe funifera, Hesperaloe parviflora, Hesperaloe noctuma, Hesperaloe chiangic, Hesperaloe tenuifolia, Hesperaloe engelmannii, Hesperaloe malacophylla, or mixtures thereof. In one particular aspect, the Hesperaloe fibers comprise Hesperaloe funifera fibers. The non-wood pulp fibers can also be bleached.

In accordance with the present disclosure, the base sheet as described above can be hydroentangled and can display a geometric mean tensile strength (GMT) of from about 3,000 g/3 in to about 30,000 g/3 in, including all increments of 10 g/3 in therebetween. For instance, the geometric mean tensile strength can be greater than about 4,000 g/3 in, such as greater than about 5,000 g/3 in, such as greater than about 6,000 g/3 in, such as greater than about 7,000 g/3 in, such as greater than about 8,000 g/3 in, such as greater than about 9,000 g/3 in, such as greater than about 10,000 g/3 in, such as greater than about 11 ,000 g/3 in.

In one aspect, the sheet product can comprise a moist wipe. In this embodiment, the sheet product can comprise the base sheet as described above and can further comprise a wetting solution incorporated into the base sheet. In accordance with the present disclosure, the sheet product or moist wipe can have a wet geometric mean tensile strength (wet GMT) of at least about 300 g/in. For instance, the wet geometric mean tensile strength can be greater than about 400 g/in, such as greater than about 600 g/in, such as greater than about 800 g/in, such as greater than about 1 ,000 g/in, such as greater than about 1 ,200 g/in.

The sheet product of the present disclosure can display a wet GMT : dry GMT ratio of greater than about 15%, such as greater than about 25%, such as greater than about 50%, such as greater than about 75%, such as greater than about 80%, such as greater than about 85%, such as greater than about 90%.

When constructing a dry product or a moist wipe as described above, the base sheet can contain staple fibers combined and hydroentangled with the non-wood pulp fibers. The staple fibers, for instance, can comprise regenerated cellulose fibers. The staple fibers can be present in the base sheet generally in an amount up to about 50% by weight. For example, staple fibers can be present in an amount of about 40% by weight or less, such as in an amount of about 30% by weight or less, such as in an amount less than about 20% by weight, such as in an amount less than about 10% by weight, such as in an amount less than about 5% by weight. In one aspect, the regenerated cellulose staple fibers can have an average fiber length of from about 4 mm to about 14 mm, such as from about 5 mm to about 11 mm and can have a decitex of from about 0.7 g/10,000 m to about 2 g/10,000 m.

In one aspect, the sheet product of the present disclosure is free of thermoplastic polymers. For instance, the nonwoven material can be free of fibers made from fossil based thermoplastic polymers. In one aspect, for example, the nonwoven material is free of polyolefin fibers and/or free of polyester fibers.

The present disclosure is also directed to a method of a sheet product. The method includes forming a fibrous suspension. The fibrous suspension contains non-wood pulp fibers in an amount of greater than 50% by weight based on the weight of fibers present, such as in an amount of 70% by weight or greater. The non-wood pulp fibers have a coarseness of from about 3 mg/100 m (0.3 dTex) to about 10 mg/100 m (1.0 dTex) and have an average fiber length of from about 1.5 mm to about 3 mm. The suspension of fibers optionally contains staple fibers, such as regenerated cellulose fibers. The fibers are suspended within a foam.

The fibrous suspension is deposited onto a forming surface to form a base sheet The base sheet is subjected to a plurality of liquid jets in order to hydroentangle the fibers. The base sheet can then be dried. Optionally, a wetting solution can be incorporated into the base sheet for forming a moist wipe. In one aspect, the non-wood fibers comprise Hesperaloe funifera pulp fibers.

Other features and aspects of the present disclosure are discussed in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: Figure 1 is a diagram of one embodiment of a process for producing base sheets in accordance with the present disclosure; and

Figure 2 is a diagram of an enlarged portion of the process illustrated in Figure 1 .

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

DEFINITIONS

The term "machine direction" as used herein refers to the direction of travel of the forming surface onto which fibers are deposited during formation of a nonwoven web.

The term "cross-machine direction" as used herein refers to the direction which is perpendicular to the machine direction defined above.

As used herein, the term “nonwoven web or material” refers to a web having a structure of individual fibers that are interlaid, but not in an identifiable manner as in a knitted or woven fabric. Nonwoven materials include, for example, carded webs, wet-laid webs, airlaid webs, foam-formed webs, and the like.

As used herein, the term “Biomass” generally refers to organic matter derived from a non- woody plant and includes both whole plants and plant organs (I ,e., leaves, stems, flowers, roots, etc.).

As used herein, the term “Bagasse” generally refers to biomass that has been subjected to a processing step such as, for example, pressing, milling, compression, or maceration, to remove a portion of the biomass water soluble solids. In certain embodiments, bagasse is prepared by subjecting the biomass to compression and maceration using a plug screw, or other form of compression screw, to extract a portion of the biomass water soluble solids.

As used herein, the term “Pulp” generally refers to a plurality of cellulose fibers that have undergone a pulping process such that the fibers have been individualized and wherein the fibers have an elongate shape in which the apparent length exceeds the apparent width. Pulp fibers can be fibrillated and can have a measurable freeness.

As used herein, the term “Fines” generally refers to fibrous water insoluble cellulosic material having a length to width aspect ratio of from about 1 to about 100 and wherein the length of the fibrous water insoluble material is less than about 0.2 mm. In certain embodiments, the amount of fines present in pulp prepared according to the present invention may be about 5.0% or less, such as about 2% or less, such as about 1% or less, such as from about 0.5 to about 2.0%. The fines content of pulp, on a length weighted basis, may be measured using an OpTest Fiber Quality Analyzer-360 (OpTest Equipment, Inc., Hawkesbury, ON) as described in the Test Methods section below. Generally, the percentage of fines on a length weighted basis is the sum of the fines length divided by the total length of fibers and fines in the sample. As used herein, the term “Brightness” generally refers to the optical brightness of a pulp sample measured in accordance with ISO 2470-1 :2016. Brightness is commonly expressed as a percentage (%).

As used herein, the term “Debris” generally refers to the weight percentage of solids retained on a MasterScreen™ apparatus fitted with a screen having a slot size of 100 pirn (0.004 inches). The amount of debris in a given pulp sample is generally measured as set forth in the Test Methods section below.

As used herein, the term “Caliper" is the representative thickness of a pulp sheet and is generally measured as described in the Test Methods section below. Caliper commonly has units of millimeters or microns.

As used herein, the term “Freeness” refers to the Canadian Standard Freeness (CSF) determined in accordance with TAPPI Standard T 227 OM-94. Freeness commonly has units of milliliters (mL).

As used herein, the term “Fiber Length” generally refers to the length weighted average fiber length (LWAFL) of fibers measured using an OpTest Fiber Quality Analyzer, model FQA-360 (OpTest Equipment, Inc., Hawkesbury, ON) as described in the Test Methods section below. Fiber length commonly has units of millimeters.

As used herein, the term “Coarseness” generally refers to the weight per unit length of fiber measured using an OpTest Fiber Quality Analyzer-360 (OpTest Equipment, Inc., Hawkesbury, ON) as described in the Test Methods section below. Coarseness commonly has units of mass per unit length, such as milligrams per 100 meters (mg/100 meters).

As used herein, the term “Hesperaloe Fiber” refers to a fiber derived from a plant of the genus Hesperaloe of the family Asparagaceae including, for example, H. funifera, H. parviflora, H. nocturna, H. chiangii, H. tenuifolia, H. engelmannii, and H. malacophylla. The fibers are generally processed into a pulp for use in the manufacture of tissue products according to the present invention. Preferably the pulping process is a high yield pulping process, such as a pulping process having a yield greater than about 60 percent, such as from about 60 to about 90 percent and more preferably from about 65 to about 90 percent. The foregoing yields generally refer to the yield of unbleached hesperaloe fiber.

As used herein, the terms “Geometric Mean Tensile” (GMT) refer to the square root of the product of the machine direction tensile strength and the cross-machine direction tensile strength of the web.

As used herein the term “Synthetic Fiber” means a non-cellulosic, thermoplastic fiber. As used herein the term “Thermoplastic" means a plastic which becomes pliable or moldable above a specific temperature and returns to a solid state upon cooling. Exemplary thermoplastic fibers suitable for the present embodiments include polyesters (e.g polyalkylene terephthalates such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like), polyalkylenes (e.g., polyethylenes, polypropylenes and the like), poyacrylonitriles (PAN), and polyamides (nylons, for example, nylon-6, nylon 6,6, nylon-6, 12, and the like). Preferred are PET fibers.

As used herein, the term “substantially free” means less than 3 wt%, alternatively less than 2 wt%, alternatively less than 1 wt%, alternatively less than 0.5 wt%, alternatively less than 0.25 wt%, alternatively less than 0.1 wt%, alternatively less than 0.05 wt%, alternatively less than 0.01 wt%, and/or alternatively free of. As used herein, “free of' means 0 wt%.

TEST METHODS

Fiber Properties

Fiber properties such as length, coarseness, percentage of fines, and fraction of very long fiber, are generally determined using an OpTest Fiber Quality Analyzer-360 (OpTest Equipment, Inc., Hawkesbury, ON) in accordance with the manufacturer's instructions. Samples are generally prepared by first accurately weighing a pulp sample. The sample mass may range from about 10 to about 50 mg (bone dry) and may be taken from a handsheet or pulp sheet. The weighed sample is diluted to a known consistency (between about 2 and about 10 mg/l). An aliquot of the diluted sample (usually 200 ml) is further diluted to a final volume of 600 ml and placed in the analyzer. The sample is then analyzed according to the manufacturer’s instructions and the output of the analyzer, such as the length weighted average fiber length, coarseness, length weighted fines, and a histogram illustrating the distribution of various fiber properties for a given sample are recorded. Generally, each reported fiber property is the average of three replicates.

The output of the fiber quality analyzer is used to calculate the Very Long Fiber (VLF) fraction, which is the sum of fiber count from 6 to 14.95 mm divided by the total fiber count. Generally, the bin data output by the instrument, which provides the number of individual fibers counted within a given fiber length range, is used to determine VLF. The total number of individual fibers counted (N) and the total number of individual fibers counted having a length of 6 mm or greater (n) are determined from the bin data. The %VLF = n/N*100.

The output of the fiber quality analyzer is also used to calculate the ratio of the length weighted average fiber length (Lw) to the number average fiber length (Ln). L« and Ln are calculated by the FQA software using the following equations:

Where n and L are determined by the instrument in the course of analyzing a sample. The ratio of the length weighted average fiber length (L_w) to the number average fiber length (L_n) indicates the fiber length distribution of the sample. A higher ratio is indicative of a broader fiber length distribution. A value of 1 indicates that all of the fibers in the sample have the same length.

Fiber coarseness is measured using the FQA instrument and is measured “as-is” without removal of fines. Consistency of the pulp sample is determined using TAPPI methods T-240 or the equivalent and the consistency (%) is recorded to the nearest 0.01%. Based upon the measured consistency, the amount of undried sample required to yield approximately 0.015 grams of oven dried pulp is calculated and weighed out and the weight recorded to the nearest 0.0001 g. The weighed undried pulp is transferred to a British pulp disintegrator or equivalent pulp disintegrator and the total volume of the sample is diluted to 2 liters with deionized water and disintegrated 15,000 revolutions according to the manufacturer's instructions. The disintegrated sample is further diluted with deionized water to a total volume of 5 liters ± 50 mL and the volume is recorded to the nearest 10 mL. The diluted sample is agitated by stirring and approximately 600 grams are weighted out into a clean beaker. The mass of the sample weighed out to the beaker is recorded to the nearest 0.1 g. The oven dried weight of the pulp sample to be analyzed is then calculated as shown in the equation below, and fiber analysis is carried out according to the manufacturer's instructions.

Caliper

Generally, sheets (e.g. webs) are dried and prepared for testing as set forth in TAPPI T 205 sp-02. Pulp sheets may be tested as is. Caliper is measured using an L & W Model code SE 050 Micrometer or equivalent. The micrometer has a circular pressure foot having an area of 2.0 cm², a lowering speed of 1 .0 mm/second and a pressure of 50 kPa. Generally, caliper is reported as the average of five samples.

Basis Weight

Generally, sheets are dried and prepared for testing as set forth in TAPPI T 205 sp-02. Pulp sheets may be tested as is. The bone dry basis weight is generally measured by first cutting the samples to a specimen size of approximately 19.05 x 19.05 cm using an appropriate cutting tool. The cut sample is then placed on a balance in an oven preheated to 105 ± 2°C. Once the weight of the sample has stabilized, the weight is recorded to the nearest 0.01 gram. The bone dry basis weight equals the measured weight (W) multiplied by 27.56. Tensile Strength

Generally Tensile is measured by forming a sheet of a particular pulp, as described herein, and then testing the resulting sheet. Generally, sheets, such as nonwoven webs, are dried and prepared for testing as set forth in TAPPI T 205 sp-02. Samples are preconditioned and tested under TAPPI conditions (50 ± 2% relative humidity and 72 ± 1 ,8°F) as set forth in TAPPI T 402. Tensile testing is carried out substantially as described in TAPPI T 494 om-01 using an MTS Systems Sintech 11 S, Serial No. 6233 tensile testing instrument. The data acquisition software was an MTS TestWorks® for Windows Ver. 3.10 (MTS Systems Corp., Research Triangle Park, NC). Generally, the tensile strengths of five samples are measured and averaged. Tensile strength generally has units of grams force per unit sample width, such as g/25.4 mm. Wet Tensile Strength

Tensile testing of wet tissue samples, such as laminates of the present invention, is conducted on a tensile testing machine maintaining a constant rate of elongation and the width of each specimen tested is one (1) inch. Generally products are tested in their product forms without separating into individual plies. For example, a 2-ply product is tested as two plies and recorded as such. The tensile tester, which is the same as described above, parameters are as follows:

Wet tensile strength measurements can be performed on pre-moistened wipes or can be performed on dry base sheets. When testing dry base sheets, prior to testing, samples are soaked in tap water at room temperature. In such instances, 5 dry sheets of a sample are weighed and combined with 220% of water based on the weight of the sheets. The water is added to the sheets so that the sheets are saturated. The water can be applied to each side of the dry sheets using a syringe. The saturated sheets are then placed in a ZYPLOK bag and stored for a week. After a week, the samples are removed, cut into 1 inch strips, and tested immediately.

Ten representative specimens are tested, and the arithmetic average of all individual specimen tests is recorded as the appropriate MD or CD tensile strength having units of grams per one inch (g/in). Debris

Debris is generally measured using a MasterScreen™ from Pulmac Systems International (Williston, VT). The MasterScreen™ is a low consistency screening device designed to mechanically separate fibers from contaminants. The MasterScreen™ is fitted with a screen (part no 3390P) having a slot size of 100 pirn (0.004 inches). Screening of pulps using a MasterScreen type instrument is generally described in T-274.

Approximately 5.0 bone dry grams of fiber are used for the analysis. The sample may be taken from a handsheet, a pulpsheet or from wet lap pulp. The 5.0 g sample is mixed with 2 L of water and disintegrate using a benchtop disintegrator at 15,000 Revolution prior to testing. The sample is screened according to the manufacturer's instructions and the rejects are collected in a collection cup fitted with a 150 mesh stainless steel screen. A wash cycle is run after the initial cycle to ensure that all of the debris retained by the screen is captured. Finally, the collection cup is rinsed with water and the rinse fluid is collected in a beaker. The rejects and wash fluid collected in the beaker is filtered under vacuum using a pre-weighed filter pad. Debris is collected on the filter pad, which is dried in an oven preheated to 105 °C overnight. The dried filter pad is weighed to the nearest 0.01 g and the weight percentage of debris is calculated. Generally, debris is reported as wt% and is the average of three samples.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

In general, the present disclosure is directed to hydroentangled nonwoven webs having excellent strength properties while minimizing or eliminating the use of wood pulp fibers, regenerated cellulose staple fibers, and/or polymer synthetic fibers. The hydroentangled nonwoven webs or sheet materials made according to the present disclosure have all different types of uses and applications and are particularly well suited for use as wipers. The product can be used as a dry product or can be premoistened and marketed as a moist wipe. In one aspect, hydroentangled base sheets can be made in accordance with the present disclosure that contain greater than 50% by weight, such as greater than about 70% by weight nonwood pulp fibers such as Hesperaloe pulp fibers and can display a geometric mean tensile strength (GMT) of greater than about 3,000 g/3 in. For instance, the base sheets can display a geometric mean tensile strength of greater than about 4,000 g/3 in, such as greater than about 5,000 g/3 in, such as greater than about 6,000 g/3 in, such as greater than about 7,000 g/3 in, such as greater than about 8,000 g/3 in, such as greater than about 9,000 g/3 in, such as greater than about 10,000 g/3 in, such as greater than about 11 ,000 g/3 in, such as greater than about 12,000 g/3 in, such as greater than about 13,000 g/3 in. The geometric mean tensile strength can be less than about 30,000 g/3 in, such as less than about 25,000 g/3 in.

The base sheets made according to the present disclosure as described above can also display excellent wet tensile strength properties. For instance, the base sheets can display a wet geometric mean tensile strength (wet GMT) of at least about 300 g/in. For instance, the base sheets can display a wet geometric mean tensile strength of greater than about 400 g/in, such as greater than about 500 g/in, such as greater than about 600 g/in, such as greater than about 700 g/in, such as greater than about 800 g/in, such as greater than about 900 g/in, such as greater than about 1 ,000 g/in, such as greater than about 1 ,100 g/in, such as greater than about 1 ,200 g/in, such as greater than about 1 ,300 g/in, and greater than about 1 ,400 g/in. The wet geometric mean tensile strength, in one aspect, can be less than about 3,000 g/in, such as less than about 2,000 g/in.

It was discovered that base sheets made according to the present disclosure containing nonwood pulp fibers, such as Hesperaloe pulp fibers, can have a much higher tensile strength and wet tensile strength in relation to similar base sheets made with conventional wood pulp fibers, particularly Northern softwood kraft fibers or Southern softwood kraft fibers

Although the base sheets can be formed using any suitable process, such as a conventional wetlaid process, in one embodiment, the hydroentangled base sheets of the present disclosure are produced according to a foam forming process. The foam forming process, for instance, in certain embodiments, is well suited to processing longer fibers.

As described above, base sheets made according to the present disclosure are primarily made from non-wood pulp fibers. The non-wood fibers can be derived from one or more plants of the genus Hesperaloe. The Hesperaloe fibers, for instance, can be obtained from Hesperaloe funifera, Hesperaloe parviflora, Hesperaloe noctuma, Hesperaloe chiangic, Hesperaloe tenuifolia, Hesperaloe engelmannii, Hesperaloe malacophylla, or mixtures thereof. In one particular aspect, the Hesperaloe fibers comprise Hesperaloe funifera fibers.

Of particular advantage, the non-wood fibers can be pulped without using the same pulping process for wood fibers. The pulping process for the non-wood fibers in comparison can be more environmentally friendly and requires less energy. The pulping process for the non-wood fibers, for instance, can comprise a mechanical pulping process alone or in combination with chemical treatments.

In one aspect, the pulping process for the non-wood fibers or Hesperaloe fibers can include harvesting biomass and cutting the biomass to an optimum size, such as having a nominal size of less than about 20 mm, such as less than about 10 mm. The cut biomass can then be passed through a press that compresses and mechanically treats the biomass in order to remove water-soluble components. The extracted and cut biomass can then be subjected to a second compression, optionally with maceration, using a screw press while impregnating the biomass with a first alkaline peroxide solution. The impregnated bagasse can then be fed to a refiner and combined with a second alkaline peroxide solution to form a primary pulp. During refining, the biomass can be fibrillated into pulp. After refining, the primary pulp can be diluted and subjected to cleaning and/or screening to further remove debris prior to an optional bleaching process. During cleaning, epidermal debris can be removed for producing a pulp having very low debris amount. For instance, the resulting pulp can contain debris in an amount less than about 5% by weight, such as in an amount less than about 2% by weight, such as in an amount less than about 1 .5% by weight, such as in an amount less than about 1% by weight. One embodiment of a process for pulping non-wood pulp is described in PCT Publication No. WO 2022/098963, which is incorporated herein by reference.

As described above, in producing the non-wood pulp fibers, the biomass is first cut to a desired size. The biomass may be cut to size at the time of harvesting using a forage harvester. The forage harvester, for instance, can use reciprocating knives, disc or rotary mowers, or large saw-like blades. The plant can be cut above the crown such as from about 10 to about 30 cm above the ground. The nominal chop length can be from about 5 to about 50 mm, such as from about 5 to about 30 mm, such as from about 5 to about 20 mm.

Cutting the biomass before the biomass is pulped or bleached can reduce the fraction of long fibers in the pulp. Further, the reduction in long fiber fraction may be achieved without a significant reduction in the fiber length. The resulting pulp, for instance, can have a length weighted average fiber length of greater than about 1 .5 mm, such as greater than about 1 .75 mm, such as greater than about 1 .8 mm, such as greater than about 2 mm, such as greater than about 2.2 mm, and less than about 3 mm.

After the biomass is harvested and cut, the biomass can be treated prior to pulping to remove at least a portion of the biomass epidermis and at least a portion of the water-soluble solids. Removal of the epidermis and water-soluble solids can be carried out simultaneously. The biomass epidermis originates from the cuticle of biomass leaves and is desirably removed for improving the efficiency of pulping and bleaching. In addition, removal of the epidermis reduces debris in the final product and may improve the physical properties of the resulting fibers. Removing the epidermis, for instance, can improve hand feel and softness and reduced lint in products made from the fibers.

Water-soluble solids and biomass epidermis can be removed, for instance, by subjecting the biomass to screw devices designed to compress and mechanically treat the biomass. The screw device can be a plug screw or other form of compression screw. In one aspect, the device is capable of a compression ratio of at least 2:1 , such as at least about 2.5:1 , such as at least about 3:1 , such as from about 2:1 to about 5:1.

During compression, the biomass can also be subjected to maceration for softening and separating the biomass into fibers and removing the epidermis and water-soluble solids. Compression can take place under a pressure of at least about 0.2 bars, such as at least about 0.5 bars, such as at least about 1 bar, such as from about 0.5 bars to about 1.5 bars.

The extracted and macerated bagasse is then converted to pulp by mechanical refining with, or without, the addition of chemicals, such as alkaline-based chemicals.

In one aspect, pulping is carried out using an alkaline peroxide mechanical pulping process. During the process, hydrogen peroxide and alkali can be added to the bagasse before or during fibrillation in a refiner. For instance, the bagasse can be impregnated by first an alkaline peroxide solution in the compression and maceration device. The impregnated bagasse can then be fed to a pulping device containing a rotating disc. A second alkaline peroxide solution can be added to the impregnated bagasse as it is fed to the pulping device.

The pulping device may operate in continuous or batch mode. The pulping device may be operated at a temperature of from about 120°C to about 190°C. The pulping device can produce a primary pulp under conditions that allow continued reaction between the alkaline peroxide chemicals and the pulp. For example, in one aspect, the pulp may be discharged to a retention vessel and retained for an hour or more at a temperature of at least about 80°F.

In one aspect, the primary pulp produced as described above can be mixed and transferred to a bleaching tower for secondary bleaching. The primary pulp can be fed to the bleaching tower at a temperature greater than about 80°C, such as from about 80°C to about 85°C and at a pH of greater than about 8.5, such as greater than about 9, such as greater than about 9.5. In one aspect, the primary pulp is quenched as it is fed to the bleaching tower for cooling the pulp to less than about 80°C. Bleaching can occur in the bleaching tower without the use of chlorine or chlorine-containing compounds. For instance, bleaching can be carried out using a non-chlorine oxidizing agent, such as peroxides, oxygen and/or ozone. Bleaching may be carried out at a temperature of from about 80°C to about 85°C and the retention time may range from about one hour to about five hours. The final pH of the bleached pulp can be from about 9 to about 11, such as from about 9 to about 10.

The resulting bleached pulp may be fed to a further processing step which can include mechanical refining, screening, washing, or the like, to produce the final pulp.

The non-wood pulp or Hesperaloe pulp can contain a relatively low degree of fines and a high freeness. The fines content, for instance, can be less than about 5% by weight, such as less than about 2% by weight, such as less than about 1% by weight. The non-wood pulp fibers can display a freeness of greater than about 400 mL, such as greater than about 450 mL, such as greater than about 500 mL, and less than about 600 mL. The non-wood pulp can have a brightness of greater than about 80%, such as greater than about 81%, such as greater than about 82%, and generally less than about 92%. As described above, the pulp can contain little to no debris. For instance, the debris content can be less than about 1% by weight, such as less than about 0.9% by weight, such as less than about 0.8% by weight

In producing base sheets in accordance with the present disclosure, the non-wood pulp fibers or Hesperaloe pulp fibers can be fed to a process for producing nonwoven webs. The webs can be made using any suitable process. For instance, the webs can be made in a wetlaid process or a foam forming process. The non-wood pulp fibers or Hesperaloe pulp fibers can be used alone or in combination with other fibers for producing the webs. The non-wood pulp fibers or Hesperaloe fibers generally have a low coarseness. For instance, the fibers can display a coarseness of less than about 10 mg/100 m. For instance, the non-wood pulp fibers or Hesperaloe fibers can display a coarseness of greater than about 3 mg/100 m, such as greater than about 3.5 mg/100 m, such as greater than about 4 mg/100 m, and less than about 10 mg/100 m, such as less than about 9 mg/100 m, such as less than about 8 mg/100 m, such as less than about 7 mg/100 m, such as less than about 6 mg/100 m, such as less than about 5 mg/100 m, such as less than about 4.5 mg/100 m. In one aspect, the web is also subjected to a hydroentangling process for improving wet and dry strength.

In general, base sheets or nonwoven webs made according to the present disclosure contain the non-wood pulp fibers or Hesperaloe pulp fibers in an amount greater than 50% by weight. For instance, the base sheet can contain the non-wood pulp fibers or Hesperaloe pulp fibers in an amount greater than about 60% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 75% by weight, such as in an amount greater than about 80% by weight, such as in an amount greater than about 85% by weight, such as in an amount greater than about 90% by weight, such as in an amount greater than about 95% by weight. In one aspect, 100% of the fibers contained in the base sheet can be comprised of the non-wood pulp fibers or Hesperaloe pulp fibers.

Optionally, the non-wood pulp fibers or Hesperaloe pulp fibers can be combined with other fibers, such as staple fibers. In one aspect, the staple fibers may comprise regenerated cellulose fibers.

The regenerated fibers are man-made filaments obtained by extruding or otherwise treating regenerated or modified cellulosic materials from woody or non-woody plants, as is known in the art. For example, but not by way of limitation, the regenerated fibers may include one or more of lyocell, viscose, rayon, and the like. In some embodiments, the regenerated fibers have an average fiber length in the range of about 3 to about 20 millimeters, such as from about 6 to about 12 millimeters. Additionally, in some embodiments, the regenerated fibers may have a decitex in the range of about 0.7 g/10,000 m to about 2 g/10,000 m. Moreover, the decitex may be in the range of about 0.9 g/10,000 m to about 1 .1 g/10,000 m. In one suitable embodiment, the regenerated fibers are not mechanically treated to alter or otherwise affect the shape the fiber. More specifically, the regenerated fibers are not fibrillated.

The amount of staple fibers, such as regenerated cellulose fibers, contained in base sheets made according to the present disclosure is generally less than about 50% by weight. In one aspect, the amount of staple fibers, such as regenerated cellulose fibers, contained in base sheets made according to the present disclosure can be minimized due to the use of the non-wood pulp fibers. For instance, base sheets can be constructed in accordance with the present disclosure that contain staple fibers, such as regenerated cellulose staple fibers, in an amount no more than 30% by weight. For instance, the base sheet can contain staple fibers, such as regenerated cellulose fibers, in an amount less than about 25% by weight, such as in an amount less than about 20% by weight, such as in an amount less than about 15% by weight, such as in an amount less than about 10% by weight, such as in an amount less than about 5% by weight.

Optionally, the staple fibers can include polymer synthetic fibers in combination with or as a substitute for the regenerated cellulose fibers. However, in certain instances, the base sheets or nonwoven webs made according to the present disclosure may be substantially free from, or free from, synthetic fibers. Hence, in one aspect, the sheet products of the present disclosure can be constructed so as not to contain any thermoplastic polymers, particularly fossil-based polymers. For example, the sheet products of the present disclosure can be free of polyolefin polymers (e.g. fibers) and/or free of polyester polymers (e.g. fibers).

As described above, base sheets or nonwoven webs made according to the present disclosure can use any suitable process. The process, for instance, can be a wetlaid process incorporating hydroentangling jets or can be a foam forming process incorporating hydroentangling jets. In one aspect, for instance, a foam forming process is used that is particularly well suited to accommodating longer fibers. FIGS. 1 and 2, for instance, represent one embodiment of a foam forming process that may be used to produce base sheets in accordance with the present disclosure. It should be understood, however, that the embodiment illustrated in FIGS. 1 and 2 is merely for exemplary purposes.

In one aspect, the process includes first selecting a fiber furnish containing primarily non-wood pulp fibers, particularly Hesperaloe pulp fibers. The fiber furnish is then fed to a web forming process which can be a foam forming process in which the newly formed web is also subjected to a hydroentangling step. After hydroentangling the fibers, the nonwoven web can then be fed to a drying process. The drying process can include through-air dryers, heated drums, or combinations thereof.

When the base sheet is foam formed, the fiber furnish can be combined with a foam to create a foamed suspension. The fibers, for instance, can be blended with water and a foaming agent.

The foaming agent, for instance, may comprise any suitable surfactant. In one embodiment, for instance, the foaming agent may comprise sodium lauryl sulfate, which is also known as sodium laureth sulfate or sodium lauryl ether sulfate. In one embodiment, the foaming agent is a nonionic surfactant which may comprise an alkyl polyglycoside. The foaming agent, for instance, can be a C8 alkyl polyglycoside, a C10 alkyl polyglycoside, or a mixture of C8 and C10 alkyl polyglycosides.

Other foaming agents include sodium dodecyl sulfate or ammonium lauryl sulfate. In other embodiments, the foaming agent may comprise any suitable cationic and/or amphoteric surfactant. For instance, other foaming agents include fatty acid amines, amides, amine oxides, fatty acid quaternary compounds, and the like.

The foaming agent is combined with water generally in an amount greater than about 0.1 % by weight, such as in an amount greater than about 1% by weight, such as in an amount greater than about 2% by weight, such as in an amount greater than about 3% by weight. One or more foaming agents are generally present in an amount less than about 50% by weight, such as in an amount less than about 10% by weight, such as in an amount less than about 8% by weight, such as in an amount less than about 4% by weight. Once the foaming agent and water are combined, the mixture is blended or otherwise subjected to forces capable of forming a foam. A foam generally refers to a porous matrix, which is an aggregate of hollow cells or bubbles which may be interconnected to form channels or capillaries.

The foam density can vary depending upon the particular application and various factors including the fiber furnish used. In one embodiment, for instance, the foam density of the foam can be greater than about 200 g/L, such as greater than about 250 g/L, such as greater than about 300 g/L. The foam density is generally less than about 600 g/L, such as less than about 500 g/L, such as less than about 400 g/L, such as less than about 350 g/L. In one embodiment, for instance, a lower density foam is used having a foam density of generally less than about 350 g/L, such as less than about 340 g/L, such as less than about 330 g/L. The foam will generally have an air content of greater than about 30%, such as greater than about 40%, such as greater than about 50%, such as greater than about 60%. The air content is generally less than about 80% by volume, such as less than about 70% by volume, such as less than about 65% by volume.

In order to form the nonwoven web, the foam is combined with a selected fiber furnish in conjunction with any auxiliary agents. The foamed suspension of fibers is then pumped to a tank and from the tank is fed to a headbox. FIGS. 1 and 2, for instance, show one embodiment of a process in accordance with the present disclosure for forming the web. As shown particularly in FIG. 2, the foamed fiber suspension can be fed to a tank 12 and then fed to the headbox 110. From the headbox 110, the foamed fiber suspension is issued onto an endless traveling forming fabric 26 supported and driven by rolls 28 in order to form a web 10. As shown in FIG. 2, a forming board 14 may be positioned below the web 10 adjacent to the headbox 110. Once formed on the forming fabric 26, the foam formed web can have a consistency of less than about 50%, such as less than about 20%, such as less than about 10%, such as less than about 5%. In fact, the forming consistency can be less than about 2, such as less than about 1 .8, such as less than about 1 .5. The forming consistency is generally greater than about 0.5, such as greater than about 0.8. The forming consistency indicates the ability to produce webs according to the present disclosure while minimizing the amount of water needed during formation

Once the wet web is formed on the forming fabric 26, the web is conveyed downstream and dewatered. For instance, the process can optionally include a plurality of vacuum devices 16, such as vacuum boxes and vacuum rolls. The vacuum boxes assist in removing moisture from the newly formed web 10.

As shown in FIG. 2, the forming fabric 26 may also be placed in communication with a steambox 18 positioned above a pair of vacuum rolls 20. The steambox 18, for instance, can increase dryness and reduce cross-directional moisture variance. The applied steam from the steambox 18 heats the moisture in the wet web 10 causing the water in the web to drain more readily, especially in conjunction with the vacuum rolls 20. From the forming fabric 26, the newly formed web 10, in the embodiment shown in FIG. 1, is conveyed downstream, subjected to hydroentangling, and dried on a through-air dryer.

After the foam formed web has been produced, the web is subjected to one or more hydroentangling steps. In the embodiment illustrated in FIG. 2, for instance, the web 10 is subjected to two different hydroentangling steps. In particular, in FIG. 2, the web 10 is hydroentangled on a first surface during a first hydroentangling step and then hydroentangled on a second and opposite surface during a second hydroentangling step. As shown in FIG. 2, for example, the process can include a first hydroentangling device 30 and a second hydroentangling device 32. The hydroentangling that occurs at each hydroentangling station may be accomplished utilizing conventional hydroentangling equipment. The hydroentangling of the foam formed web may be carried out with any appropriate working fluid such as, for example, water. The working fluid flows through a manifold which evenly distributes the fluid through a series of individual holes or orifices. Exemplary holes or orifices, for example, can have a diameter of from about 10 microns to about 200 microns. For example, the manifold may include a strip of orifices having a diameter of about 20 microns to about 50 microns. The manifold may contain about 20 to about 40 holes per inch and can include 1 to 3 rows of holes. Many other manifold configurations and combinations may be used. In the embodiment illustrated in FIG. 2, for instance, the hydroentangling device 30 includes a plurality of injectors 34, while the hydroentangling device 32 includes a plurality of injectors 36. The injectors 34 and 36 can be part of the manifold and can be in communication with a working fluid supply. In the embodiment illustrated in FIGS. 1 and 2, the first hydroentangling device 30 includes four banks of water jets or injectors 34 and the second hydroentangling device 32 also includes four banks of waterjets or injectors 36. It should be understood, however, that each hydroentangling device can include a single bank, two banks, three banks, four banks, five banks, six banks, or more of water jets.

During the hydroentangling process, the working fluid can pass through the orifices at pressures ranging from about 10 bar to about 300 bar, such as from about 20 bar to about 250 bar. Bonds between the fibers of the nonwoven web are created through hydroentangling. Thus, hydroentangling can increase the strength, such as the dray and wet strength of the nonwoven web or base sheet. Increasing the pressure during hydroentangling can increase the strength of the web that is formed.

The fluid impacts the material or web which can be supported on a foraminous surface or wire or may be supported on a porous drum surface. In the embodiment illustrated in FIG. 2, for instance, hydroentangling occurs on a first drum 38 and a second drum 40. When supported on a foraminous surface or wire during hydroentangling, the wire can have a mesh size of from about 40x40 to about 100x100. The wire or surface may also be a multi-ply mesh having a mesh size of from about 50x50 to about 200x200. In one aspect, only one side of the web 10 is hydroentangled.

As described above, alternatively, the web 10 can be placed directly onto the surface of the drum 38 and on the surface of the drum 40 during hydroentangling. Each drum can include a plurality of openings or vacuum passages for withdrawing excess water. These openings or vacuum passages can also create a pattern into the web 10 during the hydroentangling process. For example, a pattern can be formed into one surface of the web at the first hydroentangling station and a pattern can be formed into the second and opposite surface of the web at the second hydroentangling station. The pattern formed into each surface of the web 10 can be highly distinctive and can increase the aesthetic appeal of nonwoven materials made from the web. In addition, the pattern formed into the web can be three-dimensional including hills and valleys. This three-dimensional topography can further improve various properties of the material.

Once the foam formed web 10 is hydroentangled one or more times, the web can be dried using a non-compressive drying operation. For example, as shown in FIG. 1 , the foam formed web can be dried using a through-air dryer.

Referring to FIG. 1 , the foam formed and hydraulically entangled web 10 is transferred from the drum 40 to a throughdrying fabric 44 with the aid of a vacuum transfer roll 46 or a vacuum transfer shoe. If desired, the throughdrying fabric can be run at a slower speed than the web 10 to further enhance stretch. Transfer can be carried out with vacuum assistance to ensure deformation of the sheet to conform to the throughdrying fabric, thus yielding desired bulk and appearance if desired.

In the embodiment illustrated in FIG. 1 , the foam formed web 10 is transferred to a throughdrying fabric 44. Alternatively, the foam formed web can be transferred to a metal, porous sleeve that forms the circumference of the throughdryer 48.

Alternatively, the foam formed web 10 can be conveyed on the throughdrying fabric 44 over the circumference of the throughdryer 48. The throughdrying fabric can contain high and long impression knuckles. For example, the throughdrying fabric can have about from about 5 to about 300 impression knuckles per square inch which are raised at least about 0.005 inches above the plane of the fabric. During drying, the web can be further macroscopically arranged to conform to the surface of the throughdrying fabric. Flat surfaces, however, can also be used in the present disclosure.

The side of the web contacting the throughdrying fabric is typically referred to as the "fabric side" of the nonwoven web. The fabric side of the nonwoven web, as described above, may have a shape that conforms to the surface of the throughdrying fabric after the fabric is dried in the throughdryer. The opposite side of the nonwoven web, on the other hand, is typically referred to as the "air side". The air side of the web is typically smoother than the fabric side during normal throughdrying processes.

The level of vacuum used for the web transfers can be from about 3 to about 15 inches of mercury (75 to about 380 millimeters of mercury), preferably about 5 inches (125 millimeters) of mercury. The vacuum shoe or roll (negative pressure) can be supplemented or replaced by the use of positive pressure from the opposite side of the web to blow the web onto the next fabric in addition to or as a replacement for sucking it onto the next fabric with vacuum.

The web is finally dried to a consistency of about 94 percent or greater by the throughdryer 48 and thereafter transferred to a carrier fabric 50. The dried basesheet 52 is transported to the reel 54 using carrier fabric 50 and an optional carrier fabric 56. An optional pressurized turning roll 58 can be used to facilitate transfer of the web from carrier fabric 50 to fabric 56. Suitable carrier fabrics for this purpose are Albany International 84M or 94M and Asten 959 or 937, all of which are relatively smooth fabrics having a fine pattern. Although not shown, reel calendering or subsequent off-line calendering can be used to improve the smoothness and softness of the basesheet.

In one embodiment, the resulting foam formed web 52 is a textured web, which has been dried in a three-dimensional state. The texture in the web can be created due to the hydroentangling stations, due to the manner in which the web is dried using the through-dryer 48 or can be a result of both processes. For example, the web 52 can be dried while still including a pattern formed into the web.

The basis weight of webs made in accordance with the present disclosure can vary depending upon the final product. In general, the basis weight of the products may vary from about 40 gsm to about 250 gsm. The basis weight, for instance, can be greater than about 45 gsm, such as greater than about 50 gsm, such as greater than about 55 gsm, and generally less than about 150 gsm, such as less than about 100 gsm, such as less than about 90 gsm, such as less than about 80 gsm.

The process of the present disclosure can also produce webs with good bulk characteristics. The dry bulk, for instance, can generally be greater than about 3 cc/g, such as greater than about 5 cc/g, such as greater than about 8 cc/g, and generally less than about 20 cc/g, such as less than about 15 cc/g.

In one embodiment, the nonwoven material can be cut into individual sheets. The wipers may have any suitable size and shape. In one embodiment, the wiper can have a width of from about 8 cm to about 100 cm, such as from about 10 cm to about 50 cm, such as from about 20 cm to about 25 cm. The length of the wiper can be from about 10 cm to about 200 cm, such as from about 20 cm to about 100 cm, such as from about 35 cm to about 45 cm. Wipers made according to the present disclosure can be distributed as dry wipers or as moist wipes. In one aspect, the wiper can be pre-moistened with a wetting solution, such as water, a solvent, a waterless hand cleanser, or any other suitable liquid. The liquid may contain antiseptics, surfactants, emollients, humectants, and so forth. Generally, each wiper contains greater than about 100 wt. %, in some embodiments from about 150 to about 1500 wt. %, and in some embodiments, from about 300 to about 1200 wt. % of the liquid based on the dry weight of the wiper.

The wipers may be packaged in a variety of forms, materials and/or containers, including, but not limited to, rolls, boxes, tubs, flexible packaging materials, and so forth. Some examples of suitable containers include rigid tubs, film pouches, etc.

The present disclosure may be better understood with reference to the following example.

Example

Various foam formed base sheets were produced according to the present disclosure containing Hesperaloe pulp fibers alone or in combination with regenerated cellulose staple fibers. For purposes of comparison, base sheets were also produced where the Hesperaloe fibers were replaced with Northern softwood kraft fibers.

More particularly, Sample Nos. 1-38 were made containing Hesperaloe pulp fibers either alone or in combination with regenerated cellulose fibers. The Hesperaloe pulp fibers used in the samples had a very low debris content of about 1 .5% by weight. The length weight average fiber length of the Hesperaloe fibers was from about 1 .9 mm to about 2.4 mm. Sample Nos. 39-55, on the other hand, contained Northern softwood kraft fibers in combination with regenerated cellulose fibers. All of the samples had a basis weight of about 60 gsm.

Various different regenerated cellulose staple fibers were used. Sample Nos. 1-10 and 31-48 were made containing TENCEL lyocell fibers commercially available from Lenzing. Sample Nos. 11- 18 and 49-51 were made containing VILOFT viscose fibers commercially available from Kelheim Fibers GmbH. Sample Nos. 19-26 and 52-55 were made containing DANUFIL viscose fibers also commercially available from Kelheim Fibers GmbH.

The base sheets were made using a foam forming process including a hydroentangling step. The base sheets were hydroentangled on one side from four banks of fluid jets. Fluid pressure varied from 60 bar to 120 bar.

The base sheets that were formed were then tested for geometric mean tensile strength and wet geometric mean tensile strength.

The following results were obtained:

As shown above in the table, base sheets made according to the present disclosure displayed dramatically better strength characteristics than base sheets made with conventional softwood fibers.

These and 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. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims.

Claims

What Is Claimed:

1. A sheet product comprising: a base sheet containing non-wood pulp fibers in an amount of greater than 50% by weight, the non-wood pulp fibers having a coarseness of less than about 10 mg/100 m and having an average fiber length of from about 1.5 mm to about 3 mm; wherein the base sheet has been hydroentangled and wherein the base sheet displays a geometric mean tensile strength of from about 3,000 g/3 in to about 30,000 g/3 in.

2. A sheet product as defined in claim 1 , wherein the base sheet displays a geometric mean tensile strength of greater than about 5,000 g/3 in, such as greater than about 6,000 g/3 in, such as greater than about 7,000 g/3 in, such as greater than about 8,000 g/3 in and displays a wet GMT: dry GMT ratio of greater than about 15%.

3. A sheet product as defined in any of the preceding claims, wherein the non-wood fibers are derived from one or more plants of the genus Hesperaloe and are present in the base sheet in an amount of about 70% by weight or greater.

4. A sheet product as defined in claim 3, wherein the non-wood fibers obtained from Hesperaloe fun if era, Hesperaloe parviflora, Hesperaloe noctuma, Hesperaloe chiangic, Hesperaloe tenuifolia, Hesperaloe engelmannii, Hesperaloe malacophylla, or mixtures thereof.

5 A sheet product as defined in any of the preceding claims, wherein the non-wood fibers comprise Hesperaloe funifera fibers.

6. A sheet product as defined in any of the preceding claims, wherein the product further comprises a wetting solution incorporated into the base sheet.

7. A sheet product as defined in claim 6, wherein the sheet product displays a wet geometric mean tensile strength of at least 300 g/in.

8. A sheet product comprising: a base sheet containing non-wood pulp fibers in an amount of greater than 50% by weight, the non-wood pulp fibers having a coarseness of less than about 10 mg/100 and having an average fiber length of from about 1 .5 mm to about 3 mm; a wetting solution incorporated into the base sheet; and wherein the base sheet has been hydroentangled and the sheet product has a wet geometric mean tensile strength of at least 300 g/in.

9. A sheet product as defined in claim 8, wherein the sheet product has a wet geometric mean tensile strength of greater than about 400 g/in, such as greater than about 600 g/in, such as greater than about 800 g/in, such as greater than about 1 ,000 g/in, such as greater than about 1 ,200 g/in.

10. A sheet product as defined in claim 8, wherein the non-wood fibers are derived from one or more plants of the genus Hesperaloe and are present in the base sheet in an amount of about 70% by weight or greater.

11. A sheet product as defined in any of claims 8-10, wherein the base sheet contains the non-wood fibers in an amount greater than about 80% by weight, such as in an amount greater than about 90% by weight.

12. A sheet product as defined in any of claims 8-11 , wherein all the fibers contained in the base sheet comprise the non-wood pulp fibers.

13. A sheet product as defined in any of claims 8-12, further comprising staple fibers, the staple fibers comprising regenerated cellulose fibers.

14. A sheet product as defined in claim 13, wherein the staple fibers are present in the base sheet in an amount less than about 20% by weight, such as in an amount less than about 10% by weight, such as in an amount less than about 5% by weight.

15. A sheet product as defined in claim 13 or 14, wherein the staple fibers have an average fiber length of from about 4 mm to about 14 mm, such as from about 5 mm to about 11 mm, and have a decitex of from about 0.7 g/10,000 m to about 2 g/10,000 m.

16. A sheet product as defined in any of claims 8 through 15, wherein the base sheet comprises a foam formed base sheet.

17. A sheet product as defined in any of claims 8 through 16, wherein the base sheet comprises a single ply web that is non-layered.

18. A sheet product as defined in any of claims 8 through 17, wherein the base sheet has a basis weight of from about 50 gsm to about 250 gsm.

19. A wiping product comprising a plurality of individual sheets as defined in any of claims 8 through 18, wherein the plurality of individual sheets are in a stacked arrangement.

20. A sheet product comprising: a base sheet comprising non-wood pulp fibers, the non-wood pulp fibers being derived from one or more plants of the genus Hesperaloe, the Hesperaloe fibers being present in the base sheet in an amount of greater than 50% by weight based on the total weight of all fibers present in the base sheet and wherein the base sheet has been hydroentangled.

21 . A sheet product as defined in claim 20, wherein the sheet product further comprises a wetting solution incorporated into the base sheet, and wherein the sheet product displays a wet geometric mean tensile strength of greater than about 300 g/in, such as greater than about 400 g/in.

22. A sheet product as defined in claim 20 or 21 , wherein the Hesperaloe fibers are present in the base sheet in an amount of from about 90% by weight to 100% by weight based on the total weight of all fibers present in the base sheet.