KR0157409B1 - Hydraulically entangled wet laid base sheets for wipers - Google Patents

Abstract

A cloth-like nonwoven material useful for wiping and having strength, toughness, abrasion resistance and resistance to certain solvents and/or chemicals is made from mixtures of wood pulp and staple fibers randomly distributed and hydraulically entangled with each other to form a coherent entangled fibrous structure having a thickness index of at least about 0.008 and a ratio of machine direction strength to cross machine direction strength of at least about 1.5.

Description

[Name of invention]

Hydro Tangle Wet Molded Substrate Sheet For Wiper

[Field of Invention]

The field of the invention includes hydroentangled materials containing a mixture of nonwoven composite materials such as wood pulp fibers and staple fibers that can be used as wipers for industrial and other uses.

[Background of invention]

Nonwoven materials such as melt blown or spunbond polypropylene can be used as wipers. In certain applications such as automotive finishing, in order to remove oil, fingerprints and / or stains from the automotive finishing prior to painting or priming, for example, isopropyl alcohol / water, n-heptane, naphtha, And one or more volatile or semi-volatile solvents such as C ₅ to C ₇ aliphatic hydrocarbons. Certain solvents and / or other types of chemicals may cause some components, such as, for example, low molecular weight polyolefins, to melt onto the wiped surface, making the surface unsuitable for painting. Many nonwoven materials are hydrophobic and require treatment with one or more surfactants in order to be wettable. Surfactants can also be transferred to the polished surface, making the surface unsuitable for painting or priming.

Some nonwoven materials have a low inclination propensity to be used as wipers in applications where the generation of lint and dust is undesirable, such as in clean rooms for the manufacture of microelectronics. However, such wipers are usually treated with surfactants to have the absorbent and purifying properties required for such applications. Surfactant treatments are typically anionic, such as sodium dioctyl sulfosuccinate, which has a high metal ion content, for example. It is carried out using a surfactant. Such metal ions cause special problems because when present in sufficient amounts, they can adversely affect the electrical properties of the metal oxide semiconductor.

In addition, certain nonwoven materials have a slow charge dissipation rate, resulting in the accumulation of static electricity. Accumulation of pruning on the wiper causes problems such as discomfort to the user, dangerous use of flammable solvents, and damage to sensitive electrical appliances.

Nonwoven materials used for wiping applications typically require some bonding to maintain the shape of the nonwoven web. Thermal bonding can reduce the amount of active fibers available for absorption. Thermal bonding also results in harder materials that can scratch or wear soft surfaces such as freshly painted paints. Chemical bonding poses a potential problem when using extractable binders.

Nonwoven materials such as, for example, bonded carded webs and air laid webs can be hydraulically entangled into a tight web structure and used as a wiper. However, such materials are typically high strength in only one direction because the fibers in the web are oriented in only one direction during the initial web formation process. That is, the material is, for example, high strength in one direction, such as the machine direction, and relatively low strength in the transverse machine direction. This unevenness in strength is undesirable because the material is easier to tear in the weaker direction, and the material must be much stronger than necessary in one direction to satisfy the minimum strength conditions in the weaker direction.

Composite hydroentangled materials containing staple fibers and wood pulp fibers are typically made by superimposing a layer of wood pulp tissue on a staple fiber web and hydraulically tangling the two layers. Each face of the resulting hydroentangled material is generally markedly different from the other facets at the wear resistance level due to the way the material is produced.

Wood pulp and blends of wood pulp and staple fibers can be processed to produce paper tissues and paper products that can be used as wipers. Such wipers have desirable absorbency, economy and resistance to certain solvents and chemicals, but generally exhibit low strength (especially when wet), low toughness, low wear resistance and undesirable lint levels. In addition, such wipers are poor in aesthetics of sight and feel. For example, such materials are typically thin, sheet-like shapes having a thickness index of about 0.01 or typically less than 0.01. Some physical properties of such materials, such as strength and wear resistance, can be enhanced by adding a binder. However, the binder may increase the cost of the wiper and leave residue on the wiped surface.

Wipers may also be made from textile materials. Depending on the material used, the wiper may have the desired absorbency and strength, but is typically expensive and must be reused in consideration of economics. Reusable fabrics are undesirable because they can retain materials that are heterogeneous and harmful from previous use. Fabrics made from natural fibers have the disadvantage that many natural fibers (eg cotton) contain natural oils (eg cottonseed oil) that can be extracted with a particular solvent and deposited on the wiped surface. Fabrics made from artificial fibers such as polyester cannot absorb water unless the fibers are treated with a surfactant such that the fibers are wettable. The presence of surfactants is undesirable for the reasons indicated above.

[Justice]

The term peak load used in the present invention is defined as the maximum amount of load or force that is encountered in stretching the material to be broken. The peak load is expressed in units of force, ie g _f .

The term peak absorb energy (Peak EA) used in the present invention is defined as the area up to the peak or maximum load point under the load-to-elongation (stress versus strain) curve. The peak absorption energy is expressed in units of work, that is, kg · mm.

The term total absorbed energy (TEA) as used herein defines the total area up to the point of failure of a material under a load-to-elongation (strain versus strain) curve. The total absorbed energy is expressed in units of work, ie kg`mm.

The term Peak Percentang Elongation used in the present invention is defined as the relative length increase of the sample when the material is stretched to its peak or maximum load point. Vertex elongation is expressed as a percentage of the original length of the material, ie [length increase / original length] × 100.

The term Total Percentang Elongation used in the present invention is defined as the relative length increase of the sample when the material is stretched to the breaking point of the material. The total elongation is expressed as a percentage of the original length of the material, i.e. (length increase / original length) × 100.

The term thickness index used in the present invention is defined as a value expressed as the ratio of the thickness of the material to the reference weight (wherein the thickness is expressed in milliliters (mm), and the reference weight is g / m 2 (gsm)). ). For example, the thickness index can be expressed as follows.

Thickness Index = [Thickness (mm) / Reference Weight (gsm)]

The term machine direction as used herein defines the advancing direction of the resulting surface on which fibers are deposited during the formation of the composite nonwoven material.

The term cross-machine direction used in the present invention is defined as a direction perpendicular to the machine direction.

The term isotropic strength index used in the present invention refers to the peak load of a material in one direction (eg machine direction) and the peak of the material in a direction perpendicular to it (eg cross-machine direction). It is defined as a value expressed as a ratio with load. This index is usually expressed as the ratio of the machine direction peak load to the cross machine direction peak load. The material typically has an index greater than 1 unless a comparison of peak loads in a particular direction is specified. An isotropic strength index near 1 indicates that the material is an isotropic material. An isotropic strength index much greater than 1 indicates that the material is an anisotropic material.

The term staple fiber used in the present invention is an approximate average length of about 1 mm to about 24 mm (eg, about 6 mm to about 15 mm) and about 0.5 to about 3 denier (eg, Natural or synthetic fibers having an approximate denier thickness of about 0.7 to about 1.5 denier).

The term Total Absorptive Capacity used in the present invention refers to the capacity of a material that absorbs liquid, and refers to the total amount of liquid held in the material in saturation. The total absorbent capacity is determined by measuring the weight gain of the material sample due to the absorption of the liquid, expressed as the percentage of the absorbed liquid weight divided by the sample weight. That is, total absorption capacity = [(saturated sample weight-sample weight) / sample weight] x 100

As used herein, the term Morp Up Capacity refers to the ability of a material to absorb liquid after saturating and squeezing the material to mimic the multiple uses of a wiper. The morph up capacity relates to the amount of liquid remaining in the material after squeezing out the liquid from the saturated material. The morph up capacity is determined by measuring the saturation weight of the material sample and the weight difference after squeeze, and dividing the amount by the weight of the dry sample. This is expressed as a percentage of the weight of the liquid squeezed out of the sample divided by the dry sample weight. That is, [(saturated sample weight-sample weight after squeezing) / dry sample weight] x 100.

[Summary of invention]

The present invention is a nonwoven fabric similar to a fabric made from a mixture of wood pulp fibers and staple fibers, randomly distributed and hydraulically entangled with each other to form a tightly entangled fibrous structure having a thickness index greater than about 0.008 and an isotropic strength index less than about 1.5. It is aimed at solving the above-mentioned problems by providing a material.

The material of the present invention is prepared in a two step process. The material is formed by conventional wet forming techniques using warp wires. The material is then entangled using conventional hydroentangle techniques at a pressure of about 35 to about 140 atmospheres (about 500 to about 2000 psi) and at a speed of about 20 to about 300 meters / minute, thereby avoiding thermal or chemical bonding. A tight web structure was formed without.

The wet molded material of the present invention contains a mixture of randomly dispersed wood pulp fibers and staple fibers. Typical materials contain about 50 to about 90 weight percent staple fibers and about 10 to about 50 weight percent wood pearl fibers. The material may contain up to about 100% staple fibers. Nonwoven materials similar to the fabric of the present invention have a reference weight of about 30-about 150 gsm.

Staple fibers used in the present invention have a denier thickness ranging from about 0.7 to about 3 and an average length of about 5 to about 18 mm. Staple fibers can be one or more of rayon, cotton, polyester, polyamides and polyolefins such as, for example, polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers and butene copolymers. Long fiber wood pulp, such as hardwood pulp, is also particularly useful. Mixtures of long and short fiber wood pulp may also be used.

Detailed description of the invention

In accordance with the present invention, a composite nonwoven material similar to a fabric is provided having strength, toughness, abrasion resistance, resistance to certain solvents, and good visual and tactile aesthetics.

Nonwoven materials similar to fabrics are prepared from dispersions of wood pulp fibers and staple fibers formed by layers of fibers randomly dispersed on microporous surfaces by conventional wet lamination techniques using warped wires. Exemplary wet forming methods are described, for example, in US Pat. No. 2,414,833 to Osbourne, which is incorporated herein by reference.

In the headbox of the wet forming apparatus, the fiber dispersion may be diluted to a degree that contains, for example, about 2.5 g of dry fiber per liter of the fiber and water mixture. After molding on the microporous surface, the consistency of the uniform fiber layer can be about 10-30% by weight of solid fibers in water. For example, the concentration may be about 25% by weight solids. The uniform fiber layer can be moved to another surface to form an entanglement. For example, the entanglement surface may be about 35-about 100 mesh wire screen. The entangled material may be moved to another surface for the formation of a glyph. The size of the sieve and / or the texture of the microporous glyphed surface can be varied to produce various cigar and tactile properties. Coarse sieves can be used, such as, for example, about 14-35 mesh to impart a look and feel similar to fabric or fabric.

Nonwoven materials are formed by hydraulically entangled newly formed layers of randomly dispersed fibers. Representative hydroentanglement methods are described, for example, in US Pat. No. 3,485,706 to Evans, which is incorporated herein by reference. For example, tangles are used with branch tubes produced at Honeycomb Systems Incorporated with orifices 0.01 cm (0.005 inches) in diameter, 40 holes per inch, and strips with one row of holes. Can be done. Other types of branch tubes may also be used. The wet molded material can be run down the strip at a speed of about 20-about 30 meters per minute to be entangled by a liquid jet at a pressure of about 35-about 140 atmospheres (about 500-about 2000 psi). It has been found that higher strength materials are obtained by hydraulically entangled substrate sheets at slower speeds and / or higher pressures. In addition, the strength increased when further passed through the hydroentanglement apparatus.

The doorway formation can be performed by transferring the entangled material to a coarse sieve, for example 14-about 35 mesh, and running the material down the hydroentangle apparatus at a pressure of about 14-about 70 atm (about 200-about 1000 psi). .

The nonwoven material formed by hydroentanglement may be dried using one or more of conventional drying methods such as, for example, compressed air, vacuum, heat or pressure. The nonwoven material can be dried, for example, on a microporous surface such as a wire sieve. Alternatively, the nonwoven material can be dried on a seamless surface by conventional drying methods. The material dried on the microporous surface is softer and drapeable than the material dried on the grain free surface. In addition, the material dried on the microporous surface shows lower peak loads than the material dried on the grain free surface, but can be expected to have greater peak elongation.

Regarding the above description, oil and water absorption capacity and absorption rate, linting, wear resistance, electrostatic dissipation, drape stiffness, sodium ion concentration, extractable material content, peak load, peak absorption energy, total Several test methods were used to measure absorbed energy, peak elongation and total elongation.

Lint testing was performed using the Climet ™ Particle Instrument Model Cl-250 available from Climet Instrument Company, Redland, CA. The test was basically carried out with the following changes in accordance with INDA standard test 160.0-83. That is, (1) the sample size was 15 cm x 15 cm (6 inches x 6 inches) and (2) background measurements were not measured for each individual sample tested. In this test, a mechanical particle generator was used to apply bending, twisting and grinding forces to the sample specimen. The samples were arranged in the machine direction and placed in the enclosure, twisting a distance of 10.5 cm (4.2 inches) at an angle of about 150 ° at a speed of about 70 cycles per minute. The enclosure is tubed to a particle counter which attracts particles to the counter at a rate of about 0.056 m 3 (about 20 cubic feet) per hour. The flow rate through the instrument sensor is 0.028 m 3 (1.0 cubic feet) per hour. Each measurement takes 36 seconds and represents the number of particles of a particular size in 283 cm 3 (0.01 cubic feet) of air.

Grab tensile testing is based primarily on the Federal Test Method Standard (NO) using a tangled material sample of about 10 cm (4 inches) wide and about 15 cm (6 inches) long. It was performed according to Method 5100 of 191A. Both ends of the sample were fixed to a fixed surface of 6.5 cm 2 (1 square inch). Samples were tested using an Intellect II model tensile test apparatus available from [Thwing Albert] and an Instron model 1122 from [Instron Model 1122 Universal Testing Instrument], each 7.5 cm (3 inches). Jaw span and crosshead speed of 30 cm (12 inches) per minute. Peak load, peak absorbed energy, peak elongation, total absorbed energy and total elongation were measured.

The charge dissipation rate of the material was basically measured according to method 4046 of Federal Test Standard No. 101B. Test results were obtained with an electrostatic detector (Elctro / Tech Calibrated) equipped with a high voltage sample holder using a 5-1 / 2 inch by 3-1 / 2 inch rectangular sample.

The rate at which the material absorbs oil was measured as follows. A sample of about 300 mm in the transverse machine direction and about 150 mm in the machine direction was placed flat on the liquid surface of the O-ring bath containing SAE 20W / 50 motor oil. A stopwatch was used to record the time required for the sample to fully wet, ie, 99% of the surface area of the sample to be fully saturated. Non-absorbent traces of the material are not allowed in the definition of complete wet state, but individual non-absorbable fibers are allowed. The rate at which the material absorbs water was measured in the same way as for the oil except for using distilled water instead of oil.

The oil absorption capacity of the material was measured as follows: A dry standard felt of 15 cm x 30 cm, available from British Paper and Board Industry Federation, London, UK, was used with SAE 20W / 50 motors. It was immersed for at least 24 hours in an oil bath containing oil. The weight of the 10 cm x 10 cm material sample was measured to 0.01 g units, and the sample was then immersed in an oil bath over a piece of felt until completely saturated (at least 1 minute). The felt and sample were collected and suspended on the bath until the oil dripping from the sample was complete (ie, the sample exhibited a single whole color or appearance). The weight of the sample after draining the oil was weighed up to 0.01 g, and the total absorbent capacity was calculated.

The morph up capacity of the material was measured by folding the saturated sample in half and then again in half using the sample used for the total absorbent capacity test. Then, both edges of the sample were held between the thumb and the index finger, and twisted as much as possible to squeeze oil from the sample. The oil was allowed to drain while twisting the sample. The sample was released when the oil no longer ran out of the twisted sample. Samples were weighed up to 0.01 g and morph up capacity was determined.

The capacity of the material to absorb and wipe off water was measured in the same manner as used for oil except that distilled water was used instead of oil.

Drape hardness measurements were performed using a Shirley hardness tester available from Shirley Developments Limited, Manchester, UK. Test results were obtained essentially by ASTM Standard Test D1388, except that samples having a sample size of 2.5 cm x 20 cm (1 inch x 8 inches) were shown in the longer direction.

The extractable substance content and the concentration of sodium ions in isopropyl alcohol, 1,1,1-trichloroethane and distilled water were determined by the following method. Two wiper samples weighing about 2 g were refluxed in 200 ml of solvent for 4 hours using a soxhlet extraction device. The content of extractable material was calculated by evaporating the solvent to dryness and measuring the difference in weight of the vessel before and after evaporation. The content of extractable substance (%) is expressed as weight percentage of starting material. The amount of sodium in the sample was determined by measuring the concentration of sodium ions in water obtained from the slat extraction device after testing the water extractables. The concentration of sodium ions in water was measured using a Perkin-Elmer model 380 atomic hop photometer.

The abrasion resistance of the material was basically measured according to the permanent standard test method 5690: 1979 as follows. (1) The wear machine used was available from Ahiba-Mathis, Shaallot, NC as a wear tester model No. 103 under the Martindalware brand. (2) Samples were worn at 100 cycles under a pressure of 0.09 atm (1.3 psi) or 9 kilopascals (KPa). (3) A 3.8 cm (1.5 inch) diameter abrasive was cut into 90 cm x 10 cm x 0.125 (± 0.01) cm (36 inch x 4 inch x 0.050 (± 0.005) inch) pieces of glass fiber reinforced silicone rubber. Flight Insulation Incorporated, Georgia, has a surface strength of 81 A Durometer, 81 ± 9 Shore A and is a branch of Connecticut Hard Rubber. Available at Marietta. (4) The surface fluffing (fiber lofting), peeling, roping or presence of holes in the sample was investigated.

The samples were compared on a visual scale to determine wear grades of 1 to 5, with 1 indicating minor or no visible wear and 5 indicating a hole through the sample.

Example 1

About 50% by weight of a mixture of about 20% by weight of hardwood pulp and uncured polyester staple fiber (1.5 denier x 12 mm) available from Weyerhauser Company as a Grade Regular trademark Dispersed at a concentration of 0.5 wt% solids, then prepared with a handsheet of about 75 gsm on a standard 94 × 100 mesh plastic screen.

The handsheets were entangled using branch tubes available from Honeycomb Systems Inc. This handsheet was moved to a standard 100 × 92 mesh stainless steel wire. The branch was placed almost 2/1 inch on the stainless steel wire sieve. The branch pipe included a strip with a 0.005 inch diameter orifice, 40 holes per inch and a row of holes. The strip was inserted into the branch tube with the conical hole branching in the wire direction. The handsheet was run at a speed of about 20 m / min to entangle.

The handsheet is enclosed with 14,28,42,56,84 and 98 atm (200,400,600,800,1200 and 1400 psi) pressure on one side of the seat and 84 and 98 atm (1200 and 1400 psi) on the opposite side of the seat. Heightened. The flow rate of water used for the entanglement was 0.4216 m 3 / hour / cm (1.054 m 3 / hour / inch) (strip). The entangled sheet was air dried at ambient temperature. The reference weight of the dried material was about 70 gsm.

Samples of entangled material about 4 inches (10 cm) wide were tested using an Intellect II tensile test apparatus available from Twin Albert and an Instron Model 1122 available from Universal Testing Instruments. The devices each have a 3 inch long jawspan and a crosshead speed of about 30 cm / minute (about 12 inches / minute). Table 1 shows the values of the peak load, peak absorption energy, peak elongation, total absorption energy and total elongation of the dry sample for the machine direction and the cross-machine direction. In addition, similar data for wet samples were collected only for the machine orientation and listed together in Table 1.

Example 2

About 20% hardwood pulp and about 40% non-crimped polyester staple fiber (1.5 denier x 12 mm) and non-critical rayon staple fiber (1.5 denier x 12 mm) available from Weiheus Co. About 40% by weight of the mixture was dispersed and then prepared into a handsheet of about 75 gsm on a standard 94 × 100 mesh plastic screen.

Standard 100 × 92 mesh with the handsheet at 42,63,84 and 105 atmospheres (600,900,1200 and 1500 psi) on one side of the seat and 84 and 105 atmospheres (1200 and 1500 psi) on the opposite side of the seat The stainless steel wire was entangled using the apparatus and method of Example 1. The flow rate of water used for the entanglement was 0.323 m 3 / hour / cm (0.808 m 3 / hour / inch) (strip). The entangled sheet was air dried at ambient temperature. The reference weight of the dried material was about 73 gsm.

A sample of tangled material about 4 inches (10 cm) wide was tested using the apparatus and method of Example 1. Table 2 shows the values of peak load, peak absorbed energy, peak elongation, total absorbed energy, and total elongation for the machine direction and the cross-machine direction of the dry sample.

Example 3

A mixture of about 18.5% by weight of hardwood pulp, about 78.5% by weight of uncured polyester staple fiber (1.5 denier x 12 mm) and about 3% by weight of polyvinyl alcohol binder fiber, available as a Grade Regular trademark After dispersion, it was continuously formed on the microporous surface at about 60 gsm. The web was formed using a continuous warp wiremaker. This web was dried on a series of steam heating cans. Polyvinyl alcohol was added to facilitate reeling and handling.

The dry web was again wetted and then entangled using the apparatus and method of Example 1 through six passes through standard 100 × 92 mesh stainless steel wires with 126 atmospheres (1800 psi) of pressure on each side of the sheet. . The flow rate of water used for the entanglement was 0.816 m 3 / hour / cm (2.04 m 3 / hour / inch) (strip). The entangled sheet was air dried at ambient temperature. The reference weight of the dried material was about 53 gsm.

Samples of tangled material about 10 cm (4 inches) wide were tested using the apparatus and method of Example 1. Table 3 shows the values of peak load, peak absorption energy, peak elongation, total absorption energy and total elongation for the machine direction and the cross machine direction of the dry sample.

Example 4

About 19% by weight of hardwood pulp available from Weigerhauser Company as a grade regular brand, about 39% by weight of unpleased polyester staple fiber (1.5 denier x 12 mm), non-critical rayon staple fiber (1.5 denier x 12 mm) A mixture of about 39% by weight and about 3% by weight polyvinyl alcohol binder fiber was dispersed and then formed continuously on the microporous surface at about 60 gsm. The web was formed using a continuous warp wire paper machine. This web was dried over a series of steam heated cans. Polyvinyl alcohol was added to facilitate skein and handling.

The dry web was prewet and then entangled using the apparatus and method of Example 1 on a standard 100 × 92 mesh stainless steel wire. One side was prewet at pressures of 14,28 and 42 atmospheres (200,400 and 600 psi). Bundles of this face were performed three times at pressures of 56,70 and 84 atmospheres (800,1000 and 1200 psi) and at 105 atmospheres (1500 psi). The other side of the material was entangled by three passes at 105 atmospheres (1500 psi). The entangled sheet was air dried at ambient temperature. The reference weight of the dried material was about 53 gsm.

Samples of dry, entangled material about 10 cm (4 inches) wide were used with an Intellect II tensile test device having a 7.5 cm (3 inch) jaw span and a crosshead speed of about 25 cm / min (10 inches / min). Was tested. Table 4 shows the values of the peak load, peak absorbed energy, and peak strain for the machine direction and the cross-machine direction of the dry sample. Similar results for wet samples are also shown in Table 4.

Table 5 shows, for comparison purposes, the thickness index, isotropic strength index, for the tangled material of Example 2, the entangled and tangled materials of Example 4, and two commercially available materials that can be used for the wiper. Abrasion test results and drape hardness test results are described. Wiper A is a hydroentangled nonwoven material available from Sontara® (Grade 8005) (E.I.Dupont De Nemours and Company). Wiper B is made from a wood pulp / staple fiber blend formed by placing a wood pulp web on a staple fiber web and then hydraulically tangling the web. Wiper B is a Mohair Blue trademark available from France in Mawry, Nantes, France and Sodave, Angers, France. Table 5 also lists the thickness index and isotropic strength index of the materials described above.

As shown in Table 5, the hydroentangled materials of Examples 2 and 4 have a larger thickness index than the entangled materials of Example 4, Wiper A and Wiper B. The materials of Examples 2 and 4 have smaller isotropic strength indices than wipers A and B.

Table 6 provides test results for the absorption rate, total absorption capacity, and morph up capacity for oil and water of the material of Example 4. The material of Example 4 has a value significantly greater than the value for wiper B in the overall absorption capacity and morph up capacity for oil and water.

Tables 7, 8 and 9 provide test results for the materials of the present invention and various other wipers commercially available in Europe. Wiper CW1 is made of meltblown polypropylene fabric. Wiper CW2 consists of a stack of spunbond polypropylene / meltblown polypropylene / spunbond polypropylene. Wipers available under the Miracle Wipes brand are made of hydroentangled staples and cellulose fibers. Wipers, available under the CLEAN ROOM WIPERS® brand, are made of wet molded staples and cellulose fibers. Wipers, available under the DURX trademark, consist of hydroentangled staples and cellulose fibers. Wipers, available under the LABX® brand, consist of wet molded staples and cellulose fibers. The wipers available under TEXWIPE brand are made of 100% cotton woven fabric. Wipers, available under the MICRONWIPE trademark, consist of hydroentangled staples and cellulose fibers. The wiper, available under TEXBOND® trademark, is made of a spun-bonded nylon fabric. Wipers, available under the TECHNI-CLOHTH trademark, consist of hydroentangled staples and cellulose fibers.

For comparison purposes, Table 7 lists the extractable material test and sodium ion test results for the material of Example 2 and some of the aforementioned wipers. Table 7 also shows the results for the two kinds of materials prepared according to Example 2. Material H contained about 80% rayon staple fibers and about 20% wood pulp. Material F contained about 80% polyester staple fibers and about 20% wood pulp. Table 8 lists the results of the charge dissipation test for the material of Example 2, wiper A, and some of the above-mentioned wipers. Table 9 lists the results of the Climet ™ lint tests on the materials of Example 2, the entangled and entangled materials of Example 4, Wiper A and some of the aforementioned wipers.

As shown in Table 7, the material of the present invention has a good extractable material concentration compared to many other commercial wipers. As shown in Table 8, the material of the present invention without any antistatic treatment shows static charge dissipation comparable to many other commercial wipers. As shown in Table 9, the materials of the present invention exhibit relatively low lint levels and are better than many commercial wipers.

As such, it is apparent that the present invention provides a wiper that eliminates the problems associated with existing wipers. Although the present invention has been described in connection with specific embodiments, the described embodiments are intended to be illustrative and not limiting of the invention. Those skilled in the art should understand that many modifications can be made without departing from the spirit and scope of the invention.

Claims (15)

A hydroentangled cohesive fiber structure consisting of 10 to 50 weight percent wood pulp fibers and 50 to 90 weight percent staple fibers, having a basis weight of 30 to 150 gsm and a thickness index of at least 0.008. A hydroentangled cohesive fiber structure consisting of 10 to 50 weight percent wood pulp fibers and 50 to 90 weight percent staple fibers, having a reference weight of 30 to 150 gsm and an isotropic strength index of less than 1.5. A hydroentangled cohesive fiber structure consisting of 0-50 wt% wood pulp fibers and 50-100 wt% staple fibers, having a reference weight of 30-150 gsm and a thickness index of at least 0.008. A hydroentangled cohesive fiber structure consisting of 0-50 wt% wood pulp fibers and 50-90 wt% staple fibers, having a reference weight of 30-150 gsm and an isotropic strength index of less than 1.5. The structure of claim 1, wherein the staple fibers have a denier thickness in the range of 0.7 to 3 and an average length of 5 to 18 mm. The structure of claim 1, wherein the staple fiber consists of one or more of rayon, cotton, polyester, polyolefin, and polyamide. The structure of claim 1, wherein the material has an oil absorption capacity of at least 300%. The structure of claim 1, wherein the material has a water absorption capacity of at least 375%. The structure of claim 1, wherein the material has a sodium ion content of 133 ppm or less. A hydroentangled close fibrous structure consisting of 10 to 50 weight percent wood pulp fibers and 50 to 90 weight percent staple fibers, having a reference weight of 30 to 150 gsm, a thickness index of at least 0.008 and a water absorption capacity of at least 375%. Hydro-entangled close fiber structure consisting of 10 to 50% by weight wood pulp fibers and 50 to 90% by weight staple fibers, having a reference weight of 30 to 150 gsm, an isotropic strength index of less than 1.5 and an oil absorption capacity of at least 300%. . A hydroentangled close fibrous structure consisting of 0-50 wt% wood pulp fibers and 50-100 wt% staple fibers, having a reference weight of 30-150 gsm and a thickness index of at least 0.008 and a water absorption capacity of at least 375%. Hydro-entangled tight fiber structure consisting of 0-50 wt% wood pulp fibers and 50-100 wt% staple fibers, having a reference weight of 30-150 gsm, an isotropic strength index of less than 1.5, and an oil absorption capacity of 300% or more. . The structure of claim 10, wherein the staple fibers have a denier thickness in the range of 0.7 to 3 and an average length of 5 to 18 mm. The structure of claim 10, wherein the staple fibers consist of one or more of rayon, cotton, polyester, polyolefin, and polyamide.