JP2002533139A - Nonwoven fabric for wiping - Google Patents

Abstract

  (57) [Summary] A method of wiping in a clean room application using a non-woven fabric which has conventionally been considered not to be optimal for use in a clean room, and a non-woven fabric used in a clean room application.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] (the context of the present invention) 1. FIELD OF THE INVENTION The present invention relates to nonwoven fabrics used to wipe liquids and / or particles from surfaces.

[0002] 2. 2. Description of the Related Art Certain nonwoven fabrics are used to wipe surfaces. The range can be from wiping liquids from kitchen countertops at home to wiping surfaces in clean rooms where it is important that no or preferably very low particles remain on the wiped surface. .

[0003] The best nonwovens for stringent clean rooms are knitted nonwovens with sealed or unsealed edges. Such nonwovens are characterized by having moderate absorption properties and are considered "clean" in that the level of releasable particles is low. Releasable particles refer to particles that are pre-existing and released from the nonwoven, as well as particles that are newly generated when stress is applied to the nonwoven to be actually wiped. These seemingly superior nonwovens exhibit desirable properties based on testing for the number of particles that can be absorbed and released. For example, E. I. du
Pont de Nemours and Company (DuPont)
Considered to nonwovens, such as a registered trademark of Sontra ^(R) have been used in applications of certain clean room, these nonwovens is a good candidate material for particularly strict clean room applications and Had not been. Because such tests do not test the actual wiping behavior, based on such tests these nonwovens are considered to be relatively "dirty" compared to the washed knit. Because it has been. Such nonwovens have been used in clean rooms rated as Class 100 or better according to US Federal Standard 209E dated September 11, 1992, but are typically class 10 or lower (i.e., More clean)
It was not fully accepted as suitable for strict clean room applications rated to be. According to this standard, the maximum number of suspended particles at a given size is indicated. For example, Class 100 means that there are up to 100 particles of 0.5 μm in size per cubic foot, and Class 10 means that there are up to 10 particles of the same size per cubic foot. However, it would be desirable to use such nonwovens because they are very inexpensive as opposed to knitted nonwovens.

[0004] DuPont has been striving to develop inexpensive nonwovens, especially for strict clean room wiping applications. Nonwovens such as Sontra ^(R) typically have been produced by hydraulic entanglement adjustment as described in U.S. Patent No. 3,485,706 of Evans (hydroentangling) method. This patent is attached for reference. It has been found that 100% polyester nonwovens made by the hydroentanglement method are too unsuitable for strict clean room applications because of their too high hydrophobicity. Hydrophilicity can be imparted to the nonwoven fabric by washing. In this case, a surfactant is added to the nonwoven fabric. However, nonwoven fabrics made by hydroentanglement typically do not have sufficient strength to withstand such washing. Washing causes the non-woven fabric to fluff and fray. If a bonding agent is added to the hydroentangled nonwoven to increase its durability, the nonwoven will not have sufficient hydrophilicity for wiping applications.

SUMMARY OF THE INVENTION An object of the present invention is directed to a wiping material suitable for use in a clean room that has been laundered in a clean room and has been rated as having a class 10 or lower cleanliness. The present invention also relates to a method of using the nonwoven fabric for wiping in a clean room rated to have a class 10 or lower cleanliness.

[0006] DETAILED DESCRIPTION OF THE INVENTION actual wiping results of evaluating the non-woven fabric by using a dynamic test that has been newly developed, which is associated with the process, for example, Sontra some sort of non-woven fabric a ^(R) to the base Has been found to exhibit performance equal to or exceeding that of a knitted nonwoven fabric. Further, when a certain Sontra ^(R) type nonwoven fabric washing in a clean room, the surprisingly been found that the wiping properties are expected to be obtained.

[0007] Irrespective of whether liquid has been intentionally applied to the surface, or whether liquid is present as a result of spilling only, liquid must be cleaned from the surface using a wipe for cleaning purposes. When removing, there are at least three important factors. The first is the dynamic efficiency of the wiping material that can absorb liquid. Second is the number of particles already present in the spilled liquid (or on the surface to be wiped). Third, there is a very real consideration of the particles and fibers that the wipe itself leaves on the surface to be wiped.

The expected “wipe the surface”
Dry room wipes made from non-woven fabrics with "dry" capability clean the wiped surfaces more than wipers that are not. This is because residual contaminants from the spilled liquid are suspended in the liquid phase left on the wiped surface. In conclusion, being able to wipe dry is not only a desirable feature for cleanroom wiping materials from a home economic point of view, but also a critical feature of wiping spilled dirty liquids and thus removing particles from surfaces. is there.

When choosing a wiping material to remove liquid from a surface, the inherent cleanliness of the wiping material (the property expected with respect to the content of particles already present in the wiping material) It was determined that it was insignificant compared to the ability of the same material to wipe the surface dry.

(Conventional Test Method) There are many tests for evaluating the suitability of a nonwoven fabric for use as a wiping material for a clean room. By several methods, the absorption properties of the wiping material,
In particular, the functional properties of the wiping material are presented in terms of quantifying the rate and volume at which the wiping material can absorb liquid. Other tests relate to the cleanliness properties of the wipes, and in particular, determine the number of particles or fibers that may be present in the wipes or may be generated from the wipes when subjected to stress. It is a test.

[0011] Some of the most used tests to quantify the absorption properties of wipes are Mount Project, 9600, IL 60056, Illinois, USA.
40 East Northwest Highway, Institute
of Environmental Science Published in 1992, Rec
ommended Practice RP-CC004.2, "Evaluation of wipes used in clean rooms and other controlled environments", IE
It is described in S-RP-CC004.2. This test has been used to quantify the intrinsic absorption capacity of the wipes evaluated in this study.

However, there are other methods as follows.

[0013] INDA Standard Test 10.1-95, "Measurement of Absorption Time, Absorption Capacity and Wicking Rate", INDA (Association of the Nonwov)
en Fabrics Industry), 1300 Gresent
Green, Suite 125, Cary, North Carolina, USA, 275
11. It describes a basket test and a siphoning speed test.

“Wipes used in clean rooms and other controlled environments”,
IES-RP-CC004-87-T, Institute of Envir
original Science (1987), 940 East Nor
thwest Highway, Mount Project, IL 60056, Illinois, USA. It describes a test for half-absorption time.

AATCC method No. 79-1992, "Absorptivity of bleached fabrics". AATC
C Technical Manual, Association of Te
xtile Chemist and Colorists, 68, 106
P. (1993). A water drop test is described.

Textile Research Journal, vol. 54, p. 708 (
1984) Miller, B. et al. And Thomkin, I .; And TAPPI, Vol. 68 (No. 12), p. 54 (1985), Painter, E.
. V. Papers. A required absorption test (GATS) is described.

While all of these tests can distinguish wipes (also referred to as wipes) with respect to their ability to absorb liquids, these tests demonstrate that the wipes are substantially static. It is a test that describes important characteristics. None of them directly or indirectly demonstrate the ability of the wiping material to remove liquid from a surface, dynamically, i.e., under pressure and under conditions similar to those of a manual wiping operation. Absent.

When the accumulated liquid is wiped by hand with a wiping material, the liquid is absorbed into the nonwoven fabric.
However, at the same time, other factors work against this absorption process. For example, the pressure exerted during wiping delays absorption or forces already absorbed liquid out of the wipe. The difference in surface tension also has the effect of distributing the liquid between the wiping material and the surface. Even if the absorption capacity determined by the static test as described above is exceeded, not all wipes can be "wiped dry". This is especially true for materials made from hydrophobic synthetic polymers, where water marks and droplets often remain after wiping by hand.When evaluating wiping materials for cleanliness with respect to particles First, the focus is on determining how many particles are present in or on the wipe, or how many particles are released from the wipe in response to stress. Hit. Although several previous tests have tested the wipes in a dry state, the currently accepted method is to generate, collect, and count particles on the wet wipes.

The following two methods are the most useful of these wet tests. The first method is Plenum Publishing Corpo, New York, USA
ration 1990, K.K. L. Mittal, Particles in Liquids and Gases 2: Detection Characteristics and Control (Particles in Liquids)
and Gases 2: Detection Characterization
ion and Control), Mattina, C.I. F. And Pa
ley, S.M. J. A test for the number of easily releasable particles described in "Evaluation of Wiping Materials for Their Ability to Contribute to a Clean Environment: A New Method". The second method is Journal of the IES, 35 (5).
Matina, C., 21 (1991). F. And Paley, S .; J
. In a paper entitled "Evaluation of Wiping Materials for the Ability of Particles to Contribute to a Clean Environment: Creating Stress-Strain Curves", and Journal of the IES,
38 (1), 41 (1995) Oathout, J. et al. Marshal
1 and Mattina, Charles F. The method described in the article entitled "Comparison of Commercial Cleanroom Wiping Materials for Properties Related to Function and Cleanliness". These methods show how many particles are generated in response to applying a known amount of mechanical energy.

Mount Project, 940, IL 60056, Illinois, USA
East Northwest Highway, Institute of
Enviromental Science IES-R issued in 1987
There are still other tests to shake wipes in liquid on a twin-screw shaker as described in P-CC004-87-T, "Wipes Used in Clean Rooms and Controlled Environments". Used to a degree. This test method is based on Micro
Magazine, Volume 51. 5 (1998), entitled "Evaluation of Clean Room Wiping Materials to Establish Performance Benchmarks" by Atterbury, O.M. , B
Achattacharjee, H .; R. Cooper. D. W. , Domi
nique, J .; R. Paley, S .; J. Siegerman, H .; In this article, a modification was made to add a surfactant and then count the particles by scanning electron microscopy. Although this is said to be a test that more closely resembles the stress in practical use than the test for releasable particles described above, the amount of energy imparted by such shaking is known. Absent.

[0021] All references relating to these test methods are attached for reference.

(Test Method of the Present Invention) There are few methods for evaluating the ability of a nonwoven to wipe a surface in a dry state. Proceeding IDEA '98 (INDA), 12.1 (19
98) MacFarlene, K. et al. A paper entitled "Evaluation of Wiping Properties" describes such a test. In the present invention, Macfa
A dynamic wiping efficiency test method was developed using several aspects of the rlen test method.

Mattina, C.A., in Cleanrooms '96 East, 1996, Proc. F. McBride, J .; Nobile, D .; And Turner. K. The paper entitled "Cleanliness of Wiped Surfaces: Particles Remaining as a Function of Wiper and Volume of Solvent Used" states that when the wipes were tested with various increases in absorption capacity. Data is provided for particles from the wipe remaining on the clean surface. When the wipes are tested with a volume of liquid less than the absorption capacity, relatively few particles remain, but in sharp contrast to all wipes that exceed the absorption capacity. The material left a significant number of particles. Surprisingly, regardless of composition or structure, once the test has been performed beyond the absorption capacity of the wipe, the number of particles left by the wipe will be very similar. According to conventional knowledge, a so-called "clean" nonwoven will leave less particles proportionally than a so-called "dirty" nonwoven. However, it has been observed that the ability of the nonwoven to remove liquid from the surface is extremely important. This is because particles are left excessive only when liquid is left behind by the wiping material.

Several elements of the method of Mattina et al. Were used to develop a second test method to determine the number of particles remaining on the surface after dynamic wiping. If the liquid test sample intentionally contains particles from an external source, this test will be used to determine the particle removal capacity (
PRA) will be referred to as a test.

Next, the details of the new test method will be described.

Dynamic Wiping Efficiency As noted above, several changes were made to the Macfarlene apparatus and method. The wiping speed is set to 50 cm / sec for better realizing the actual wiping operation.
Instead of 25 cm per second. Using a 50cm stainless steel dish, 45c
A free distance of about 36 cm was created in front of a 1 kg sled inside a length dimension of m. The dimensions of the tread surface of the sled are 114 mm at the edge, and the most usual size of 229 × 229 mm (9 × 9 inch) wiping material is folded and stored in a quarter.

Instead of a single sample of 1 mL of water, different volumes up to about 130% of the absorption capacity were used, measuring the inherent absorption capacity there. Efficiency curves were thus created as a function of the sample volume or of the absorption capacity of the wipe for any wipe as needed.

Instead of placing the nonwoven and sled directly on the sump and allowing some time to elapse before commencing traversal, place a sample of the liquid in front of the sled and pull the sled through it into the sump. I was crowded. This is an operation that more closely resembles the phenomenon of actually wiping spilled liquid.

The following equipment was used.

Balance; top-loading, shielded pan capable of reading to 0.01 g. Made of stainless steel, the internal dimensions are 45 x 28 x 7 cm, large enough to contain a volume of water to count the particles.

Sledge: made of stainless steel, 1 kg, bottom 114 × 114 mm, bent bottom edge of the sled has a lip-like part, and a clip loaded with a spring folded into a quarter-folded sample. It was mounted using. Two stainless steel screws are fixed to both outer edges of the sled within this bent tip edge.

Dispenser: Brinkmann Bettrop Bullet, Mod
el 25, volume of liquid is accurately and reproducibly distributed.

Water: Convenient (but not required) if present, use the same clean water as when counting particles. See description below.

Apparatus: A yoke is made by attaching a polyester string to the sled at the stainless steel screw. Attach a second polyester string (about 4 feet long) to the midpoint of the yoke. Using this string, the sled is pulled by hand at a speed of about 25 cm / sec.

It should be understood that a device equivalent or suitably similar to the above could be used.

The method is as follows: A single layer of wiping material (229 × 229 mm nominal) is folded into quarters and its dry weight M _d is measured to the nearest value of 0.01 g.

The wiping material folded into 2/4 is clipped to the sled so that one bulging fold is made at the leading edge.

[0038] 3. Place the sled on the stainless steel dish so that the leading edge is perpendicular to the long dimension axis of the dish.

[0039] 4. If the specific absorption capacity A _i of the wiping material is not known, the above-mentioned IES
This is determined using another layer of material according to the method of T-RP-CC004.2. From the calculated A _i and the measured mass of each wipe, the capacity per layer A _ip [mL / g] for each wipe is calculated. This amount is necessary to know what percentage of the test volume of each volume of liquid is the absorption capacity.

[0040] 5. Using a dispenser, a sample of water of a desired volume v _c, placed in a dish at a point forward about 1~2cm tip edges of the sled.

6. Using a string, pass through the water and along the long axis of the dish, slide the sled at a speed of about 25 cm / sec for a distance of about 36 cm (can lift the sled and wipe without touching the lips of the dish) (A free distance from the front of the sled, which can leave space). The sled and the wiping material are removed from the plate by lifting the sled smoothly and quickly using a string.

[0042] 7. Remove the folded wipe from the sledge, determine the wet weight m _w, and determine the weight of absorbed water from the difference. Density of water to calculate the volume v _s of absorbed water with (25 ℃ 0.997g / mL in). Dynamic wiping efficiency DWE is calculated by the volume vs of water absorbed divided by the volume v _c of the sample, fix the%.

[0043] as a function of _{DWE = 100 [(m w -m} d) /0.997] / v c = 100v s / v c DWE absolute volume v _c of the sample, also as a function of the value of the sample to A _i Can be represented. The value of the relative sample is represented by 100v _c / A _ip.

Particle Removal Capability To determine the ability of the wipe to remove particles from the surface, the dynamic wiping efficiency test was combined with certain elements of the test described by Mattina et al. Quantification of the number of particles left on the surface caused by using the trapping material was performed. The difference is that a known number of polystyrene spheres were added to the liquid sample, and a 1/4 folded sample was used instead of the unfolded wiper sample. The result of this method was called "Particle Removal Ability" or PRA. For all practical purposes, tests on DWE and PRA were performed once with liquid samples with and without particles.

A quarter-fold wipe (attached to the underside of the sled as described above and pulled across a clean stainless steel dish) is applied by dispersing polystyrene spheres of known size at a known concentration. Was dragged through a sample of water. After removing the sled and nonwoven from the dish, the particles and liquid remaining on the dish were dispersed in clean water and counted with a separate particle counter. The value of the number of remaining particles from the sample, expressed relative to the percent of the absorbent capacity of the volume v _c and nonwoven liquid sample samples were presented to 100v _cj A _ip.

Since the water sample had a significant number of spheres (approximately 10 × 10 ⁶ ) added, after wiping and dilution, it was sufficient to distinguish it from the number of particles originally present in clean water. A number of balls remained. For convenience, 1.0-3.0μ of the separation particle counter.
A sphere with a diameter of 1.59 μm was chosen so that measurements could be safely taken in the m channel.
Using a μL syringe, the syringe was adjusted by pushing the syringe little by little until 10 × 10 ⁶ spheres could be reproducibly delivered, and the spheres were settled. At this point in the work, a clean workstation with a horizontal laminar flow (Atoms Tech, Mode)
l6302). The air created at this workstation has been monitored in use using a separate particle counter (Met One, Model 227) and is subject to US Federal Standard 209E, September 11, 1992, "Particulate Suspended Particles in Clean Rooms and Clean Zones." The cleanliness requirements of Class 10 or higher as defined in the “Cleanliness Standard (Class)” were always met.

In addition to the materials and equipment described above, the following were used: Sphere: polystyrene, particle sediment standard, Duke Scientific Sur
f-Cal Scanner, PD 1600, 1.59 μm, concentration 3 × 10 ⁸
/ ML.

Syringe: Hamilton, 50 μL.

Water: Milli consisting of a reverse osmosis unit (Milli-RO 10 Plus), an array of filters and ion exchange beds (Milli-Q UHF Plus) and a 0.2 μm filter (Millipak 40) mounted at the point of use.
pore system.

Particle Counter: PMS Microlase with Corrosive Liquid Samler (Corrosive Liquid Sampling Apparatus) Model 200
r Particle Spectrometer (PMS microlaser particle spectrometer) (μLPS) The method is as follows.

1. The stainless steel dish is cleaned and the concentration of particles (1.0-3.0 μm) originally present when 1000 mL volume of water is placed therein is measured.

[0052] 2. A single layer of wiping material (229 × 229 mm nominal) is folded into quarters and its dry weight M _d is measured to the nearest value of 0.01 g.

3. Clip the wiping material folded in quarters to the sled with a clip so that one bulging fold is made at the leading edge.

[0054] 4. Place the sled on the stainless steel dish so that the leading edge is perpendicular to the long dimension axis of the dish.

[0055] 5. Using a μL syringe, precipitate a sample of the particles a few cm in front of the leading edge of the sled.

6 Using a dispenser, add a sample of the desired volume vc of water onto the particles.

[0057] 7. Using a string, the sled is pulled at a rate of about 25 cm / sec for a distance of about 36 cm along the long axis of the dish through the water. Remove the sledge from the plate.

[0058] 8. Remove the folded wiping material from the sledge and determine DWE by the method described in the previous section.

[0059] 9. Add a known volume (200-1000 mL is convenient) of clean water to the dish and determine the concentration of particles ranging from 1.0 μm to 3.0 μm. After subtracting the concentration of the originally present particles, the number of particles left from the sample is determined.

[0060] 10. Repeat with the value of the different _{v c.}

[0061] 11. For each value of _vc , determine the particle removal capacity (PRA), that is, the number of particles left from the sample, including some contribution from the wipe.

[0062] PRA can be expressed as a function of the absolute as a function of volume v _c, also of the sample to A _i values of the sample. The value of the relative sample is represented by 100v _c / A _ip.

Examples 1 to 9 The following materials were subjected to the dynamic test method. The results obtained are described below.

Example 1 is DURX ^™ 670, a pattern-free nonwoven made by 55% wood pulp and 45% polyethylene terephthalate, with an average basis weight of 70.6 g / m ² , made by a hydroentanglement method. . This material is from Massachusetts, USA
Berkshire Corporation of Great Barrington
on is commercially available.

Example 2 is MICROFIRST ^™ , a 24-mesh patterned nonwoven made of 45% wood pulp and 55% polyethylene terephthalate with an average basis weight of 54.2 g / m ² made by a hydraulic entanglement method. It is. This material is Be
Commercially available from rkshire Corporation.

Control run 3 is SUPERPOLX 1200 ^™ , which has an average basis weight of 15
A knitted nonwoven fabric made of 100% polyethylene terephthalate at 4 g / m ² and washed in a clean room with unsealed edges. This material is Berkshi
Commercially available from re Corporation.

Example 4 is DyNamix ^™ 4990Q, which is a lyoc
ell) 75.2 average basis weight of 42% and polyethylene terephthalate 58%
It is a 40-mesh patterned non-woven fabric made by a hydraulic entanglement method of g / m ² . This material is commercially available from Berkshire Corporation.

Example 5 is DyNamix ^™ 6900Q, which has an average basis weight of 112 g /
were washed in a clean room consisting of 100% polyethylene terephthalate m ² is a nonwoven fabric made of hydro entanglement alignment method. Raw material of the nonwoven fabric is Sontara ^(R) 8007, which is washed in a clean room in the following manner. This washed material DyNamix ^™ 6900Q is available from Berkshire Corporation.
n.

[0069] Control Example 6 is TexWipe ^(R) TX309, which is an average basis weight of 1
It is a woven nonwoven fabric of 100% cotton of 73 g / m2. This material is available from The Texwipe Co. of Upper Saddle River, New Jersey, USA.
mpanykara is available.

[0070] Control Example 7 is Alpha 10 ^(R) TX1010, this average basis weight is made of 100% polyethylene terephthalate with 141 g / m ^2, the edge is a knitted nonwoven fabrics laundered in a clean room that is sealed . This material is The T
Available from Exwipe Company.

Control Example 8 is PROWIPE 880, which has an average basis weight of 85.9 g.
/ M ² of 100% polypropylene. This material is commercially available from Berkshire Corporation.

Example 9 is DyNamix ^™ 5900Q, which has an average basis weight of 102 g /
This is a non-woven fabric made by a hydroentanglement method comprising 100% lyocell of m ² . This material is commercially available from Berkshire Corporation.

For washing in a clean room, various cycles are even used by experts in the art. The use of a non-woven fabric having a relatively high basis weight of at least about 102 g / m ² would be able to withstand one cleanroom wash per drying cycle. This process uses a nonionic surfactant to stir the nonwoven in hot water (minimum 120 ° F. (49 ° C.)) (about 1.8 gallons of water per pound of nonwoven (15 liters per kg)). Includes a process. The hot water was water previously produced by reverse osmosis treatment and had a conductivity of 4 to 6 microohms / cm. Wash the nonwoven in deionized water (about 1.2 gallons of water per pound of nonwoven (10 liters per kg)). Deionized water had a resistance of about 18 microohm / cm. Filter both types of water to 0.2μ. Total wash time is limited to a maximum of about 40 minutes.

The absorption capacity and releasable particles for each example were IEST-RP-CC000
This was performed using the Po test described in 4.2. The results are shown in the table below. Note that the results below are for particles in the 1-3 μm range. Absorbing capacity is expressed in units of mL / g, and releasable particles are expressed in units of 10 ⁶ / m ² .

[0075]

[Table 1]

Samples were tested for DWE using the method described above. Most wipes are 2.00,5
. 00,10. , 15.0, 20.0 and 30.0 mL, and the volume calculated to be excessive (about 130%) for the absorption capacity of the individual wipes. For convenience, only the results for the test at a volume of 10 mL and an absorption capacity of about 130% are reported for this part of these examples. The test volume was converted to a% volume basis by dividing by the absorption capacity of the individual material layers. The actual amount of liquid absorbed for each sample is shown and is also expressed as a percentage of the test volume. Tables 2 and 3 show data for a test volume of 10 mL and an absorption capacity of about 130%.

[0077]

[Table 2]

[0078]

[Table 3]

Samples were tested for PRA using the method described above. The test was carried out the same series of volumes as described in the test of DWE, but added ¹⁰⁶ polystyrene spheres in each test volume. The results for a test volume of 10 mL and an absorption capacity of about 130% are shown in Table 4 as the number of particles left. Expressing the same data as% of particles removed gives the particle removal efficiency (PRE). Table 5 shows the data thus represented.

[0080]

[Table 4]

[0081]

[Table 5]

Example 5 was found to exhibit very good properties for use in a strict clean room, especially when tested by a newly developed method. It was also found that the lyocell nonwoven fabric of Example 9 made by the hydroentanglement method was an excellent candidate product for use in clean rooms, especially in terms of dynamic wiping efficiency (DWE). In addition, the results of the particle removal capacity (PRA) test show that pulp / pulp / pulp test results, especially when tested with a volume of test solution that exceeds the inherent absorption capacity of the material.
Polyester (Examples 1 and 2) and lyocell / polyester (Example 4)
3) shows that the nonwoven fabric produced by the hydroentanglement method has a surprisingly high rating. These examples of non-woven fabrics made by low cost hydraulic entanglement are a significant advance in general wiping applications, especially in strict clean room applications. The nonwoven fabric of the present invention has performance comparable to and often above that of the comparative knitted nonwoven fabric, which has hitherto been considered the industry standard, especially in cleanroom applications.

It should be noted that melt spun nonwovens having substantially continuous filament polymeric fibers would be useful in the present invention. Such a nonwoven fabric has continuous fibers in the same manner as the above-mentioned knitted nonwoven fabric. The polymer fiber is a polyester or polypropylene, or a bicomponent fiber of polyester and polypropylene as described in U.S. patent application Ser. No. SS-2911, filed concurrently by DuPont on Dec. 20, 1999. Can be.

Examples 10 to 13 In Example 10 of the present invention, D washes in the clean room used in Example 5 above.
yNamix ^™ 6900QL. Control Example 11 Sontara ^(R) st
Yle 8007, which is substantially the same as the nonwoven fabric of Example 10 except that it is not washed in a clean room. Control Example 12 Sontara ^(R)
style 8000, which has a low basis weight of 39.9 g / m ² and has not been washed in a clean room, but has been treated with a surfactant to improve absorption properties. Control Example 13 is SUPERPLOX 1200, a polyester knit nonwoven fabric washed in a clean room similar to Example 3 above.

The examples were tested in various static test methods using the above test methods, and in DWE and PRA tests. Table 6 shows the results.

[0086]

[Table 6]

Example 10 of the present invention shows excellent cleanliness data, low fiber efflux and excellent absorbency. This exceeds the performance of the unwashed sample example in ion contamination.

[0088] Control Example 11 shows reasonable cleanliness based on the number of residues when biaxial shaking is performed, but medium to high fiber runoff and very poor absorbency.

Control Example 12 shows the particle content, absorption capacity and absorption rate, extractables,
And inferior in ion content. Treatment with a surfactant helps to increase the absorbency, but increases the amount of unwanted ions. However, surprisingly, when using a three-layer construction, the nonwoven exhibits a PRA close to Example 10 of the present invention.

Control Example 13 is similar to the nonwoven fabric of the present invention with respect to particles and ions when biaxially shaken. Since it is a continuous filament, it is excellent in the outflow property of the fiber, but does not behave similarly to the fiber of the present invention in the absorption capacity.

The results of the particle removal ability show the excellent cleaning ability of the nonwoven fabric of the present invention of Example 10. In this case 10 ⁷ but did not remain only tested to 11,000 particles in the particle, when no washing of Control Example 11 5,300,000
Particles remained. In this regard, in particular, Example 10 outperformed Control Example 11, which left 73,000 particles. Particularly surprisingly, the nonwoven fabrics of the present invention combine the properties of good cleanliness, determined by conventional static methods, with the good absorption properties and good performance in removing particles (functional cleanliness). I have.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] January 8, 2001 (2001.1.8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 8

[Correction method] Change

[Contents of correction]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 16

[Correction method] Change

[Contents of correction]

14. The wiping material according to claim 8, wherein said nonwoven fabric has a particle removal efficiency of at least 96% in a test volume representing 130% of its absorption capacity.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 17

[Correction method] Change

[Contents of correction]

15. determined by FED-STD-209E Class 10
9. The wiping material according to claim 8, wherein the wiping material is adapted for use in a clean room that is cleaner than that.

Claims (1)

Claims: 1. A method of using a nonwoven fabric for wiping in a class 10 or cleaner clean room as determined by FED-STD-209E, wherein the nonwoven fabric comprises polyester, lyocell, And a fiber selected from the group consisting of a blend of polyester and lyocell. 2. The method of claim 1, wherein the nonwoven fabric has a dynamic wiping efficiency of at least 89% in a 10 mL (milliliter) test volume. 3. The method of claim 1, wherein the nonwoven has a dynamic wiping efficiency of at least 70% in a test volume representing 130% of its absorption capacity. 4. The method of claim 1, wherein the nonwoven has a particle removal efficiency of at least 98% in a 10 mL test volume. 5. The method according to claim 1, wherein the nonwoven fabric has a particle removal efficiency of at least 96% in a test volume representing 130% of its absorption capacity. 6. The method of claim 1 wherein said nonwoven fabric comprises about 42% by weight lyocell and about 58% by weight polyester. 7. The method according to claim 1, wherein said non-woven fabric is made by a hydroentanglement method. 8. A wiping material comprising a polyester nonwoven fabric washed in a clean room. 9. The wiping material according to claim 8, wherein the nonwoven fabric is made by a hydroentanglement method. 10. The wiping material according to claim 8, wherein the nonwoven fabric has a basis weight of about 102 g / m ² or more. 11. The nonwoven fabric has at least 98% in a 10 mL test volume.
9. The wiping material according to claim 8, which has a dynamic wiping efficiency of: 12. The wiping material according to claim 8, wherein said nonwoven fabric has a dynamic wiping efficiency of at least 70% in a test volume representing 130% of its absorption capacity. 13. The nonwoven fabric of claim 10 wherein at least 99%
The wiping material according to claim 8, wherein the wiping material has a particle removal efficiency of: 16. The wiping material according to claim 8, wherein said nonwoven fabric has a particle removal efficiency of at least 96% in a test volume representing 130% of its absorption capacity. 17. Class 10 determined by FED-STD-209E
9. The wiping material according to claim 8, wherein the wiping material is adapted for use in a clean room that is cleaner than that.