JP4395361B2 - Clean room wiper - Google Patents

Description

  The present invention is a manufacturing process of precision mechanical parts and electronic parts represented by large-scale integrated circuits, electronic devices, electronic parts, liquid crystals, optical systems, etc. in which minute dust, dust, fibrous scraps, etc. are avoided, The present invention relates to a clean room and a clean room wiper to be used in a process in which an environment that is often installed in a manufacturing process of pharmaceuticals, medical devices, etc., an aseptic room, a food-related manufacturing process, and the like is controlled.

  Products used in a clean room or an environment-controlled room are required to have special performance necessary for maintaining the environment. In particular, it is required that the generation of minute dust, dust, fibrous scraps, material fragments, and the like (hereinafter collectively referred to as lint) be small. As is well known, contamination in clean rooms and lint brought in are often caused by the workers themselves and the items used by the workers, so they are special for items such as work clothes and wipers. Attention is being paid and improvements are continuing.

  One potential source of particulate contamination in a clean room is a wiper that is used in a wiping operation normally performed in the clean room. For example, when manufacturing and assembling semiconductors and integrated circuits, not only wipers are used to wipe off dirt in the work process, but also the cleaning of the surfaces of various equipment and equipment, and the inner surfaces of walls and rooms. For this purpose, wipers are widely used. In these operations, in order to prevent the release and divergence of lint from the wiper to the surrounding environment, various devices have been devised for the wiper used in a room where the environment is controlled, such as a clean room.

  For example, in Patent Document 1, generation of lint from a cut portion is controlled by cutting a sheet of a woven or knitted fabric made of a thermoplastic material into a predetermined size and thermally fusing thermoplastic fibers constituting the peripheral portion thereof. A wiper has been proposed. Although this wiper can suppress the occurrence of lint, it is necessary to use a thermoplastic material, so if it is impregnated with a solvent or the like during use, components such as oligomers of the thermoplastic material may elute, and instead it is necessary to clean them. When cleaning a plate of a screen printing machine that prints the circuit of a printed wiring board, for example, there is a danger that static electricity will be generated by wiping and lint will adhere to the plate It was something to do.

  Moreover, since the heat-sealed part at the end is very hard, there is a risk of scratching when the product or the like is wiped off. Furthermore, since the heat-sealed portion is very brittle, there is a risk that the lump of the resin may fall off from the fused portion due to friction such as wiping, and the indoor environment and the product may be contaminated. It may also be used to wipe off water and solvents spilled on the desk or floor surface of clean rooms, etc., but because it is made of thermoplastic resin material, it has poor water absorption and water retention and has sufficient performance. There was also a problem that it could not be demonstrated. In addition, since a woven or knitted fabric is used, there is an economical problem.

  As described above, the wiper of the woven or knitted fabric using the thermoplastic fiber has a considerably high level in terms of suppressing lint, but has a considerable defect in the original function of the wiper.

  Moreover, in a clean room where the degree of cleanliness is not so required, for example, in a clean room of class 10 or higher (class 100, etc.), various types of wiper functionality are more important than lint generation, and non-woven wipers are used from an economical point of view. ing. The clean room class here is a class of cleanliness defined by the US FED-STD 209D, which indicates the cleanliness of air. The smaller the class number, the more contained in the air. Indicates that the number of dust is small and the air is clean.

  For example, Patent Document 2 proposes a wiper of an acetylcellulose long fiber nonwoven fabric, and further describes that a rayon nonwoven fabric is also used in this document. Patent Document 3 proposes a wiper made of a thermoplastic polyvinyl alcohol-based long fiber nonwoven fabric. Furthermore, Patent Document 4 proposes a polyester nonwoven fabric wiper that can be used in a clean room of class 10 or less and a nonwoven fabric wiper composed of a polyester and lyocell blend. Patent Document 5 proposes a wiper for a clean room using a cupra ammonium rayon continuous long fiber nonwoven fabric which is a regenerated cellulose continuous long fiber nonwoven fabric.

  As described above, it is known to use a non-woven wiper as a wiper in a clean room. However, for example, the wiper described in Patent Document 2 swells with acetone, which is a solvent usually used in the process of manufacturing electronic materials, and an eluate is generated. However, the wiper described in Patent Document 4 has a problem in that the polyester oligomer is eluted by the solvent or the antistatic property.

  Therefore, the best non-woven wiper for clean room having the above-described problems and having various functions is a wiper using a regenerated cellulose continuous long-fiber non-woven fabric. For example, the wiper using the regenerated cellulose continuous long-fiber nonwoven fabric described in Patent Document 5 has a lint because the surface of the nonwoven fabric is composed of continuous long fibers, and fluff and single fibers from the surface are very rarely dropped. There are few, and it is excellent in the water absorption, antistatic property, and chemical resistance which are the features of cellulose. In addition, a non-woven fabric is formed by self-adhesion of fibers and entanglement of three-dimensional fibers, and no binder is used for web formation. It is a suitable material as a wiper for the machine. As a regenerated cellulose continuous long-fiber nonwoven fabric by the cupra ammonium method rayon as described above, for example, Benrise (registered trademark) manufactured by Asahi Kasei Fibers Co., Ltd. is known, and the fiber diameter is known to be about 10 to 13 μm.

  However, regenerated cellulose fibers such as cuprammonium method rayon and viscose method rayon swell with water and extend with low stress, so there are problems in handling when wet, and the wiper's original wiping property is not intended. This is not always sufficient, and there has been a strong demand for improvement in performance.

As a wiper for a clean room having improved wiping properties, for example, Patent Document 6 proposes a wiper for a clean room made of a polyester ultrafine fiber knitted fabric. Although this wiper has improved wiping properties, it still has problems with solvent resistance, oligomer elution, antistatic properties, resin dropping, and the like.
Therefore, a cellulose nonwoven fabric that has overcome the above problems has been strongly demanded as a wiper for a clean room.

JP-A-2-45017 Japanese Patent Application Laid-Open No. 5-261105 JP 2001-329458 A Special Table 2002-533139 JP 2000-51130 A Japanese Patent Laid-Open No. 9-119067

  The present invention has good wiping properties, shape retention when wet, water absorption, antistatic properties, chemical resistance, elution from wiper when impregnated with solvent, minute dust, dust, fibrous scrap, material An object of the present invention is to provide a wiper for a clean room in which the occurrence of shards or the like is extremely small and the whiteness required for specific applications and the yellowing due to steam sterilization are improved.

  In order to solve the above-mentioned problems, the present inventors have reduced the single yarn fineness constituting the cellulose fiber nonwoven fabric and controlled the orientation of the fibers constituting the nonwoven fabric, so that the shape retention when wet is good. The inventors have found that the wiping property can be improved, the whiteness required for specific applications, and yellowing by steam sterilization are improved, and the present invention has been made.

That is, the present invention is as follows.
(1) Cellulose fibers having a fiber arrangement coefficient of 0.65 to 1.35, in which cellulose fibers having a fiber diameter of 2.9 to 7.1 μm occupy at least 60% of the number of fibers on one surface of the nonwoven fabric Clean room wiper using non-woven fabric.

  (2) The clean room wiper according to the above (1), wherein the cellulose fiber nonwoven fabric has a wet form retention of 80% or more.

  (3) The wiper for a clean room according to the above (1) or (2), wherein the cellulose fiber is a long cellulose fiber.

  (4) The wiper for a clean room according to any one of the above (1) to (3), wherein the cellulose fiber is a regenerated cellulose continuous long fiber.

Hereinafter, the present invention will be described in detail.
Examples of the cellulose fiber nonwoven fabric referred to in the present invention include, for example, a long fiber nonwoven fabric such as lyocell which is a purified cellulose described in JP-T-2002-521585, and a short fiber obtained by spinning a fiber spun using the same stock solution as a short fiber. Nonwoven fabric, for example, regenerated cellulose continuous that is made by continuously spinning a rayon stock solution of cupraammonium method on the net by flow-down tension spinning method, and making the nonwoven fabric by tangling the fibers by self-adhesion of the fiber itself or hydroentanglement if necessary A long fiber nonwoven fabric is mentioned.

When the cellulose fiber non-woven fabric is a short fiber non-woven fabric, the softness is improved and the bulkiness is improved. However, the fiber is detached from the nonwoven fabric surface, and the lint performance is lowered. In the case of a cellulose long-fiber nonwoven fabric, the constituent fibers are long fibers, and therefore, the dropout of the fibers is less than that of the cellulose short-fiber nonwoven fabric, which is preferable.
Further, in the case of the regenerated cellulose continuous long-fiber nonwoven fabric, as described above, the nonwoven fabric is formed by self-adhesion or hydroentanglement, and a binder component such as an adhesive resin is not used when forming the nonwoven fabric. Is preferable because it is very rarely eluted by a solvent.

  The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention has at least a cellulose fiber having a fiber diameter of 2.9 to 7.1 μm, preferably 2.9 to 6.5 μm, more preferably 2.9 to 5.8 μm. The nonwoven fabric occupies 60% or more, preferably 80% or more, and most preferably 100% of the number of fibers on one side surface.

The fiber diameter here means the diameter of the fiber when observed at a magnification at which the single fiber is about 1 cm in the electron micrograph of the nonwoven fabric surface. In the present invention, the fiber diameter is measured at an arbitrary 200 points on the surface of the nonwoven fabric, and the abundance ratio is 60% or more, that is, 120 points or more are composed of fibers having a fiber diameter of 2.9 to 7.1 μm. It means being.
When the fiber diameter of the cellulose fiber nonwoven fabric is 2.9 to 7.1 μm, the number of self-adhesion points and the degree of entanglement of the fibers themselves are increased as compared with the conventional cellulose fiber nonwoven fabric having a fiber diameter larger than this range. , Elongation is regulated, and shape retention during drying and wetting is improved.

  Further, due to irregular reflection, the whiteness is improved and the yellowness is lowered as compared with a conventional cellulose fiber nonwoven fabric having a fiber diameter larger than this range. If the fiber diameter is smaller than the above range, the single fiber may be cut and fluffed at the time of manufacture, or the single fiber may be easily cut by friction during use as a product, and the dropped fiber may increase. . Therefore, it is not preferable that the fiber diameter is smaller than the above range because the characteristics of the long fiber nonwoven fabric are particularly impaired.

  In the cellulose fiber nonwoven fabric used for the clean room wiper of the present invention, at least 60% of the number of fibers on one surface of the nonwoven fabric has a fiber diameter of 2.9 to 7.1 μm. The term “one-sided surface” as used herein refers to a surface that can effectively use a fiber having a fiber diameter of 2.9 to 7.1 μm. Depending on the purpose of use, both sides may have a fiber diameter in this range. Good. When the cellulose fiber having a fiber diameter of 2.9 to 7.1 μm is less than 60% of the number of fibers on both side surfaces of the nonwoven fabric, it can satisfy shape retention, whiteness, yellowness, wiping property for use, etc. I can't get anything. Moreover, there may be a case where sufficient performance cannot be exhibited in terms of infusion performance and liquid diffusibility.

Moreover, since the fiber diameter affects various performances and effects, the average fiber diameter may be used, but in the present invention, the average fiber diameter is defined as follows.
Average fiber diameter I: Average value of fiber diameters of fibers having a fiber diameter of less than 2.9 μm in the above measurement Average fiber diameter II: Average value of fiber diameters of fibers having a fiber diameter of 2.9 to 7.1 μm in the above measurement Average fiber diameter III: Average fiber diameter of fibers exceeding 7.1 μm in the above measurement

The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention has a fiber arrangement coefficient of 0.65 to 1.35, preferably 0.75 to 1.25.
The fiber alignment coefficient here means that measured by the following method.
A 20 cm square sample (sample) is prepared, and fixed to a cylinder having a diameter of 12 cm with a rubber band or tape in a state where no wrinkles are formed on the surface of the sample. Add 10 ml of killer whale stamp ink aqueous dye system S-1 (red) to 1 liter of distilled water to prepare an evaluation solution. The evaluation liquid is injected into a burette having a tip diameter of 0.7 mm.

As shown in FIG. 1, a sample, a burette, and a camera are set. The camera is fixed and the burette is fixed laterally moving. The camera position is set 10 cm above the sample surface, and the burette position is set 5 cm above the sample surface.
The evaluation solution is dropped on 5 drops (0.05 ml) of the sample at a rate of about 0.01 ml per drop, and at the same time, the burette is moved sideways to take a photograph of the diffusion state after 10 seconds. At this time, a JIS standard metal scale is placed on the surface of the sample so that it can be converted into an actual diffusion area as shown in a photograph. The diffusion area can also be obtained from the photograph by image processing or the like.

A fiber arrangement coefficient is measured using the obtained photograph. Usually, the liquid diffuses in an elliptical shape. The diameter a of the ellipse in the machine axis direction and the diameter b in the direction perpendicular to the machine axis are measured, and the fiber arrangement coefficient c is calculated by the following equation.
Fiber arrangement coefficient c = b / a
The fiber arrangement coefficient is a coefficient indicating a diffusion state when the liquid is dropped, and indicates the fiber arrangement direction because the diffusion of the liquid has a high correlation with the fiber arrangement direction. When the fiber arrangement in the machine axis direction is large, the fiber arrangement coefficient is less than 1. If the arrangement of fibers in the machine axis and the direction perpendicular to the machine axis is the same, the liquid diffusion state is circular, and in this case, the fiber arrangement coefficient is 1. Further, when there are more fibers arranged in the direction perpendicular to the machine axis than in the machine axis direction, the fiber arrangement coefficient exceeds 1.

  When the fiber arrangement coefficient is less than 0.65, the fibers are mainly arranged in the machine axis direction, and the number of entanglement and coupling with the fibers existing in the direction perpendicular to the machine axis decreases. The form retainability is small, the elongation in the direction perpendicular to the machine axis increases, the width becomes easy to enter, and tearing easily occurs in the machine axis direction. For example, in the case of a long roll wiper, it may be wiped while applying tension in the machine axis direction, but if the dimension in the width direction changes during wiping, a wiping remaining part may occur or the width direction Since it extends in the length direction as it becomes smaller, the diameter at the time of winding increases, which may cause a machine trouble. That is, in a normal processing process, tension is often applied in the machine axis direction, and the processing performance may be deteriorated due to the width of the non-woven fabric entering the process.

  The elongation of the nonwoven fabric will be described in more detail. The elongation of the nonwoven fabric is composed of two factors, that is, the elongation of the tissue and the elongation of the fiber itself, and the elongation of the tissue itself is more dominant than the elongation of the fiber itself. For this reason, the elongation is greatly influenced by the difference between the entanglement and the number of coupling points. If the fiber arrangement coefficient is less than 0.65, the elongation at break is affected mainly by the elongation of the fiber itself. On the other hand, tissue elongation easily occurs due to a decrease in the number of entanglements and bonding points. Therefore, a phenomenon occurs in which the width in the direction perpendicular to the mechanical axis is increased by applying tension in the mechanical axis direction.

  On the other hand, when the fiber arrangement coefficient exceeds 1.35, the fibers are mainly arranged in the direction perpendicular to the mechanical axis, and the elongation of the nonwoven fabric is greatly influenced by the tissue elongation, and the influence of the elongation of the fiber itself is reduced. For this reason, although tissue elongation occurs, the number of entanglements and bonding points is very large, so even if tension is applied in the machine axis direction, the influence in the width direction does not increase. However, when the fiber arrangement coefficient exceeds 1.35, it becomes a very hard nonwoven fabric, which may cause trouble in actual use.

  As described above, the breaking elongation and the fiber arrangement coefficient in the machine axis direction can be obtained by controlling the single fineness of the fibers forming the nonwoven fabric and the arrangement direction of the fibers in the machine direction during production. By reducing the single fineness, the number of fibers constituting the non-woven fabric with the same basis weight increases compared to the one with a large single fineness.For example, in the case of regenerated cellulose continuous long fibers, the number of self-adhesion points increases and the fibers The number of confounding points increases significantly. By increasing the restraint point, a nonwoven fabric that is difficult to stretch, that is, has a low elongation at break, is formed. For example, in a regenerated cellulose continuous long fiber nonwoven fabric, web formation is performed by dispersing the yarn on a net or the like after spinning. It is no exaggeration to say that the mechanical properties in the machine axis direction and in the direction perpendicular to the machine axis are determined by the dispersion state of the yarn at this time. The control of the dispersion state can be adjusted by, for example, applying vibration in the traveling direction (machine axis direction) and the vertical direction (width direction) to the net on which the web is formed, and drawing a sin curve on the spun yarn. When the frequency and the vibration width in the width direction are increased, it is possible to obtain a nonwoven fabric that does not easily stretch in the machine axis direction.

The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention preferably has a wet form retention of 80% or more, more preferably 90% or more.
The wet form retention rate here is measured by the following method.
FIG. 2 schematically shows the measurement method. A sample is prepared in a size of 5 cm × 12 cm so as to be vertically long in the machine axis direction of the nonwoven fabric, and a measurement part is created by marking the center part of the upper and lower 1 cm parts. 10 times the sample mass (W1) of pure water is uniformly applied to the sample. 1 cm above and below the sample is sandwiched between sample holding plates and fixed. After 30 wt% of the load of the sample mass per 1 m ² (bottom of the sample holding plate is set to 10 wt% of the sample mass per 1 m ^2, load to this and plus) was suspended for 30 seconds over, except Weight (remove the lower sample holding plate), and after 30 seconds, measure the length L (cm) of the measurement portion, that is, the length between the sample holding plates. The initial sample length (the length between sample holding plates before loading) is 10 cm, and the wet form retention rate is calculated by the following equation.

Wet form retention rate (%) = {(10− (L−10)) / 10} × 100
The wet form retention rate greatly correlates with the handleability at the time of wiping with a nonwoven fabric in a wet state. When the wet form retention rate is 80% or more, the non-woven fabric does not have a joll when wiping in a wet state, the handleability is good, and the non-woven fabric is not torn, so that the wiping surface is not re-contaminated. .

  The wet form retention rate can be controlled by the arrangement direction of the fibers forming the above-described nonwoven fabric, the entangled state of the fibers, that is, the abundance of single fibers. In order to improve the wet form retention rate, the number of fiber entanglement points can be increased by increasing the number of fibers arranged in the direction perpendicular to the mechanical axis, decreasing the single fiber density of the nonwoven fabric, and increasing the number of fibers present. By increasing, the wet form retention rate can be made suitable.

  In the cellulose fiber nonwoven fabric used for the clean room wiper of the present invention, the fibers constituting the nonwoven fabric are preferably cellulose long fibers, and more preferably regenerated cellulose continuous long fibers. A cellulose long fiber nonwoven fabric means long fiber nonwoven fabrics, such as a lyocell which is the refined cellulose described in the Japanese translations of PCT publication No. 2002-521585, for example. In addition, the regenerated cellulose continuous long fiber nonwoven fabric referred to here corresponds to, for example, a cupra continuous long fiber nonwoven fabric manufactured by a cupra ammonium method. Recycled cellulose continuous long-fiber nonwoven fabric has bonding points formed by self-adhesion of single fibers, and can be controlled relatively easily in the production direction of the single fibers. The occurrence of lint from the wiper surface is extremely small compared to short fiber nonwoven fabrics. Cupra is also preferable because it is a material for medical gauze specified by the Pharmaceutical Affairs Law and is suitable for use in pharmaceutical applications.

  In order to obtain a cellulose long fiber nonwoven fabric having a fiber diameter of 2.9 to 7.1 μm, for example, when a regenerated cellulose long fiber nonwoven fabric is obtained using a cupra ammonium ammonium rayon stock solution, the diameter of the spinning nozzle for spinning the stock solution is conventionally set. It can be suitably obtained by adjusting the viscosity of the undiluted solution and the undiluted solution temperature, controlling the coagulation rate, and taking a higher draw ratio than before.

As for the cellulose fiber nonwoven fabric used for the wiper for clean rooms of this invention, white coefficient is preferable 7 or more, More preferably, it is 10 or more.
The white coefficient as used in the field of this invention means what was calculated | required by the following measurements.
The sample is measured in a state where 12 sheets are stacked. The measurement surface is a surface where the fiber diameter is defined. The standard color management system Macbeth CE-3000 manufactured by Sakata Inx Co., Ltd. was measured five times using the C light source, including the field of view, the specular gloss, and the ultraviolet region of the light source. Tristimulus values are obtained, and whiteness and yellowness are calculated from the following equations.

Whiteness = 4 × (0.847Z) -3Y
Yellowness = 100 × (1.28X−1.06Z) / Y
In addition, as long as the measurement principle and the light source are the same, the measurement may be performed with another measuring device.
The white coefficient is calculated by the following equation.
Whiteness coefficient = Whiteness / Yellowness The whiteness coefficient is a coefficient value that more significantly indicates the whiteness of the fabric. Usually, a white fabric has a large whiteness and a small yellowness. Therefore, it is possible to more clearly grasp the degree of whiteness by using the white coefficient.
In addition, in the nonwoven fabric generally said to be white, this requirement is satisfied when the yellowness shows a negative value.

  It is estimated that the whiteness coefficient of the cellulose fiber nonwoven fabric used in the clean room wiper of the present invention is improved because the single fiber is small, so that the inside of the fiber can be refined at the time of manufacture, and irregular reflection occurs on the nonwoven fabric surface because the single fiber is small. In addition, since the whiteness is improved and the yellowness is lowered, the white coefficient is greatly improved. If the fiber diameter does not satisfy the above conditions, the white coefficient may not be 7 or more. Therefore, the non-woven fabric used in the present invention is a non-woven fabric having a very high whiteness and a low yellowness without being bleached or subjected to a fluorescent whitening treatment.

  When the white coefficient is 7 or more, for example, when used in a clean room for medical treatment or a clean room for food use, the clean feeling is excellent. In order to improve the white coefficient, as described above, it is possible to improve it by controlling the fiber diameter, the scouring conditions during spinning, and the like.

The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention preferably has a steam sterilization yellowing coefficient of 1.8 or less, more preferably 1.6 or less.
Steam sterilization yellowing coefficient refers to that measured by the following measurement.
About the sample, yellowness Y1 is measured by the method similar to the measurement of a white coefficient. Next, steam sterilization is performed at 120 ° C. for 30 minutes with the sample wrapped in aluminum foil. The sample is allowed to stand for 24 hours under 20 ° C. × 65% RH condition, and then the yellowness Y2 is measured by the same method as the measurement of the white coefficient. The steam sterilization yellowing coefficient is calculated by the following equation.

Steam sterilization yellowing coefficient = Y2 / Y1
Steam sterilization yellowing coefficient indicates the rate of change in yellowness due to steam sterilization. A normal cellulose long fiber nonwoven fabric increases yellowness by steam sterilization. When the steam sterilization yellowing coefficient is 1.8 or less, an excellent clean feeling can be obtained, for example, in pharmaceutical and medical uses or food related uses that are often used after steam sterilization. In the present invention, the reason why the steam sterilization yellowing coefficient is low is presumed to be due to the fact that the single fineness is small, so that the inside of the fiber can be refined during spinning, and due to irregular reflection. Further, it is preferable that the yellowness is low regardless of the presence or absence of steam sterilization, because the cleanliness is improved for medical and medical uses and food related uses. In order to obtain a low steam sterilization yellowing coefficient, as described above, it can be achieved by controlling the fiber diameter, the scouring conditions during spinning, and the like.

The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention preferably has a basis weight of 8 to 150 g / m ² , more preferably 10 to 120 g / m ² , and a thickness of 0.03 to 1 mm, more preferably 0. 0.05 to 0.8 mm. The basis weight and thickness can be appropriately selected depending on the application. When the basis weight is in the above range, the strength as a non-woven fabric is high, it is difficult to break when it is made into a product, there is no problem in actual use such as the occurrence of lint, and the fiber filling density is moderate Therefore, it is soft and has excellent wipeability.

The cellulose fiber nonwoven fabric used for the clean room wiper of the present invention may have a pattern formed of openings, recesses, irregularities and the like. The shape of the opening, the recess, and the mesh pattern may be appropriately selected depending on usage. For example, an independent pattern such as an elliptical shape, a circular shape, a square shape, a rectangular shape, a rhombus shape, or a combination of concave and convex shapes, for example, a herringbone shape pattern may be selected as appropriate. In addition, the arrangement pattern, for example, staggered arrangement with independent openings and recesses may be selected as appropriate. However, in the case of providing a separate opening or recess of the pattern described above, the area per one opening or recess is preferably 0.05 to 10 mm ^2, more preferably 0.1 to 5 mm ^2, more preferably Is 0.2 to ^2.5 mm ² . When the area per opening or recess is within the above range, contribution to wiping can be effectively obtained, and even if the object to be wiped passes through the opening or recess, the hands and the like are contaminated. There is nothing to do. The area per opening or recess is binarized by placing, for example, black colored paper on the back side of the nonwoven fabric, that is, in a state where it can be separated into black and white, so that the opening or recess can be distinguished. Thus, it may be obtained by image processing or the like.

  In addition, such surface modification is performed, for example, by treating the nonwoven fabric with a high-pressure liquid flow in a state where the nonwoven fabric is placed on a mesh-like net, so that the nonwoven fabric fibers on the net entanglement point are surrounded by the high-pressure liquid flow. It can obtain suitably by being pushed. Further, for example, a method of so-called embossing, in which an uneven pattern is formed on the surface of a metal roll and an uneven shape is formed through a nonwoven fabric while applying pressure between the metal roll and the rubber roll, can be suitably obtained.

  Depending on the presence or absence of the mesh pattern on the surface of the wiper, it is possible to control the functionality such as wiping property and liquid permeability and to improve the design.

  If the cellulose fiber nonwoven fabric used for the clean room wiper of the present invention is within the range specified above, for example, yarns having different single fineness may be mixed, or may be combined with other materials or other nonwoven fabrics. Also good. By such means, it is possible to give higher functionality.

  For example, when a cellulose nonwoven fabric is laminated on a spunbond synthetic fiber nonwoven fabric and three-dimensionally entangled with a high-pressure liquid flow to obtain a composite nonwoven fabric, although the elution property to a solvent is reduced, the mechanical strength is improved, and the end Since the portions can be fused, the occurrence of lint can be further reduced. Also in the case of compounding, it is preferable to combine the long-fiber nonwoven fabrics with each other because generation of lint can be suppressed.

  The form at the time of use of the wiper for a clean room of the present invention is not particularly limited, and an easy-to-use shape can be appropriately selected according to the application. For example, the shape when the wiper is spread can be used without any problem, such as a polygon such as a square or a rectangle, a circle or an ellipse, and may be appropriately selected depending on the application.

Moreover, it does not specifically limit about a usage form, What is necessary is just to select suitably according to a use. For example, when the basis weight is high, a lithographic shape may be used, and when the basis weight is low, it may be folded. Moreover, when using it by folding, the folding method can also be selected suitably.
Examples of the folding method include multiple folding such as four-folding, six-folding, and eight-folding, and folding methods such as full end folding, C-folding, and Z-folding.

  For example, the multiple fold is defined by the number divided by the fold when the folded member is opened to the maximum size. In the case of four folds, it is divided into four parts by folds, in the case of six folds, it is divided into six parts by folds, and in the case of eight folds, it is divided into eight parts by folds. Further, the folding method is not particularly limited, and it may be folded so as to obtain an appropriate size and thickness depending on the work content.

For example, when a flat plate of about 25 cm square (625 cm ² ) is folded in four, both ends are folded into two, and the short end of the finished rectangle (12.5 cm × 25 cm) is folded into two. That's fine. In this case, the wiping surface is about 12.5 cm square (156.25 cm ² ), and most of the portions are overlapped by four. This size is a size that can roughly cover the palm portion of a general adult, improving workability.

For example, when a planographic plate having a size of about 25 cm square (625 cm ² ) is folded in six, first, the upper end and the lower end of about 8 cm are combined and folded inward, and then the opposite end is folded to the previously folded portion. At this time, it is folded so that the end when the lithographic plate is folded first enters inside. The short end of the completed rectangle (8.5 cm × 25 cm) may be combined and folded into two. In this case, the wiping surface is about 8.5 cm × 12.5 cm (106.25 cm ² ), and most of the portions have a structure in which six sheets overlap. This size is a size that can roughly cover a general adult finger portion, and improves workability.

For example, when a lithographic plate of about 30 cm × 25 cm (750 cm ² ) is folded in eight, it is folded on both sides by about 7 cm toward the center with an end of 25 cm. Fold the resulting rectangle (16 cm x 25 cm) at the center of the short end so that the first folded end is inside. The short end of the completed rectangle (8 cm × 25 cm) may be folded and further folded into two. In this case, the wiping surface is about 8 cm × 12.5 cm (100 cm ² ), and a structure in which most of the portions are overlapped by 8 sheets. This size is a size that can roughly cover a general adult finger portion, and improves workability.

For example, when a lithographic plate having a size of about 25 cm × 30 cm (750 cm ² ) is to be folded inward (12 folds), the end on one side of 30 cm is folded 6 cm toward the center of the end of 25 cm, and then 30 cm on the other side Is folded toward the center of the end of 7 cm × 25 cm. Match the finished rectangle (12 cm x 25 cm, 3 cm overlapped part in the center part is about 1 cm x 25 cm) with the short ends aligned near the center of the long end so that the first folded end is inside. Fold like so. The completed rectangle (12 cm × 15 cm) may be folded at the center of the long end so that the short end enters inside. In this case, the wiping surface is about 12 cm × 7.5 cm (90 cm ² ), and most of the portions are twelve stacked. Since the end portion does not protrude from the surface, lint dropout is greatly reduced, which is preferable.

For example, when a flat plate of about 25 cm square (625 cm ² ) is C-folded, both ends are folded in the same direction toward both ends, and the short end of the finished rectangle (12.5 cm × 25 cm) is further combined. Fold it in two. In this case, the wiping surface is about 12.5 cm square (156.25 cm ² ), and most of the portions have a four-layer structure. Since only one side of the end portion is on the surface, lint dropout is reduced, which is preferable.

For example, when a planographic plate having a size of about 25 cm square (625 cm ² ) is Z-folded, both sides are folded in opposite directions toward both ends. This folding method is especially a wet wiper, and the container is of a box type or pouch product. When one end surface comes to the center of the extraction surface, the wiper can be easily removed by picking up the end surface. preferable.

  The clean room wiper of the present invention may have, for example, a long winding shape, that is, a roll shape. The roll-shaped wiper is suitably used for an automated machine or continuous wiping. When using it in roll form, it is preferable that it is a long-fiber nonwoven fabric. This is because the end portion exists only in the length direction, and therefore the end portion of the wiper that is a lint generation source is reduced as compared with the piece-shaped wiper described above. The winding length, width, and the like are not particularly limited, and may be appropriately selected depending on the application.

  In addition, the clean room wiper of the present invention can arbitrarily add various functions that can be additionally provided to the wiper. For example, wipers provided by pre-wetting with water and / or various solvents, wipers that have been sterilized or sterilized by heat treatment, gamma ray irradiation, electron beam irradiation, ethylene oxide gas treatment, pyrogen or endotoxin A wiper of which the amount is added, such as a wiper whose amount is controlled, is also included in the wiper of the present invention, and the addition of these arbitrary functions is not limited at all.

  The size of the wiper for a clean room of the present invention is not particularly limited, and can be appropriately selected according to the intended use and intended purpose. For example, in the case of a lithographic plate, a 3 to 12 inch square (7.5 to 30 cm square) is generally used. In the case of folded products, those having the above sizes are generally used, and in the case of a roll shape, those having a width of about 5 to 100 cm and a winding length of about 3 to 50 m are generally used. It has been.

The packaging form, packaging material, and the like of the clean room wiper of the present invention are not particularly limited, and may be appropriately selected depending on the application.
For example, the folded product is put in a bag, and several of the bags are put in a cardboard box.

In addition, for example, when antistatic properties are particularly required, it is preferable that the bag for inserting the wiper is an antistatic bag. Since static electricity is generated by friction between objects, it is desirable to consider friction with the bag when the wiper is taken out in order to reduce static electricity. In this case, it is preferable to use a bag having a surface resistivity value of about 10 ⁶ to 10 ¹⁰ Ω / □.

An example is introduced about the manufacturing method of the cellulose fiber nonwoven fabric used for the wiper for clean rooms of this invention.
A preferred embodiment in the present invention is a cellulose continuous long fiber nonwoven fabric, for example, Ben Rize (registered trademark) manufactured by Asahi Kasei Fibers Co., Ltd. corresponds to this. The manufacturing method of the cupra nonwoven fabric is to extrude a stock solution in which a cotton linter whose degree of polymerization has been removed and dissolved in a copper ammonium solution is removed from a spinneret (spinner) having pores (stock solution discharge holes), and together with water The inside of the funnel is dropped and deammoniated to solidify the stock solution, and then stretched, and then shaken onto a net to form a web. At this time, the fiber that is shaken down to the net draws a sin curve by vibrating the net in a direction perpendicular to the traveling direction.

  Stretching at the time of spinning can be 100 to 500 times, and the stretching ratio can be arbitrarily adjusted by changing the shape of the spinning funnel and the amount of spinning water flowing down. By changing the draw ratio, the single fineness and the strength of the nonwoven fabric can be changed. It is also possible to control low-molecular weight cellulose, so-called hemicellulose, remaining in a small amount in the stock solution by changing the amount of spinning water and the temperature. Further, by controlling the traveling speed and vibration width of the net, it is possible to control the fiber arrangement direction and control the strength, elongation and the like of the nonwoven fabric. The shape of the spinning funnel is preferably a rectangular shape, and the length of the spinning funnel to be flowed down is preferably 100 to 400 mm, and the slit width of the flowing down outlet is preferably 2 to 5 mm. The diameter of the stock solution discharge hole of the spinning nozzle used for spinning is preferably 0.1 to 0.5 mm, and the shape is preferably round.

  Moreover, it is preferable to laminate | stack a web from the meaning which ensures the uniformity of a nonwoven fabric, and the number of lamination | stacking is preferable 3-10 sheets. Produces a nonwoven fabric in which the laminated web is entangled with high-pressure water flow after regenerating or scouring cellulose in the web state, for example, by the method described in Japanese Patent Nos. 787914 and 877579. You can also At this time, in order to impart design properties, it is possible to make holes or irregularities in the nonwoven fabric depending on the conditions of the high-pressure water flow and the net pattern disposed below and / or above the nonwoven fabric. The obtained nonwoven fabric can be obtained as a dried or wound product. Since the process from spinning to winding is performed in a series of steps, the fibers are connected continuously without being cut.

  Moreover, although the manufacturing process of the wiper for clean rooms is not specifically limited, It is preferable that appropriate conditions are satisfied with the use application. For example, in the case of medical use, it is preferable to manufacture in a GMP designated factory or in a clean room suitable for the use environment. For example, in the case of a folded product, the raw fabric is slit in the vertical direction with a rotary cutter, folded while being cut in the width direction with a folding machine, a fixed number of bags are packed in bags, and a fixed number of bags are put in cardboard and shipped. These operations are preferably performed in a clean room suitable for the use environment of the wiper.

  The wiper for a clean room of the present invention has good wiping property, shape retention property when wet, water absorption, antistatic property, chemical resistance, elution from wiper when impregnated with solvent, minute dust, dust, fibrous There are very few occurrences of scraps, material fragments, etc., and the whiteness required for specific applications and the yellowing due to steam sterilization are improved.

The following examples further illustrate the present invention.
Measurement methods, evaluation methods, etc. are as follows.
(1) Abundance ratio of fiber diameter The fiber diameter was measured by the method described above.
(2) Average fiber diameter As described above, measurement was performed by dividing into three regions of I, II, and III.
(3) Fiber arrangement coefficient It measured and calculated by the above-mentioned method.

(4) Wet form retention rate Measured by the method described above.
(5) White coefficient It measured by the above-mentioned method.
(6) Steam sterilization yellowing coefficient It measured by the above-mentioned method.
(7) Weight per unit area, thickness It measured by the method of JIS-L-1096 description.

(8) Wipeability Apply lipstick on the mirror and spread it with tissue paper to create an oil film that is as uniform as possible. Prepare clean room wiper “Zavina Minimax (registered trademark)” and Japanese Pharmacopoeia cotton gauze by Kanebo Gosei Co., Ltd. as standard products.
Take one wiper, hold it with your thumb, index finger, and middle finger, and wipe the oil film once with your index finger belly. By this method, a wiping test was performed on the standard product and the sample wiper, and the wiping property was subjected to sensory evaluation. The determination was performed according to the following criteria, and each sample was evaluated five times to obtain an average value.

10th grade: The oil film can be wiped off almost completely (in the state where it was wiped off with "Zavina Minimax").
Grade 5: The oil film has been wiped off properly, but there are streaks left behind.
First grade: The oil film is hardly wiped off and feels stretched (when wiped with a Japanese pharmacopoeia cotton gauze).
In addition, between the 1st class and the 10th class, an intermediate class is interpolated relatively.

(9) Impurity qualitative test The nonwoven fabric may contain a component that is easily eluted in water, such as a surfactant, depending on the production method. The following foaming test qualitatively evaluated the impurity content of the nonwoven fabric.

[Bubbling test evaluation method]
Preparation: Condition the sample overnight in a constant temperature room. (20 ° C, 65% RH)
B) Put 150 cc of pure water into a beaker.
B) Put 5g of the sample after humidity adjustment in 150cc of pure water and soak for 5 minutes.
C) After 5 minutes, stir while shaking the beaker for 1 minute.
D) Collect 60 cc of liquid from the above beaker into a 100 cc cylinder.
E) Cover the cylinder by hand and shake it up and down 20 times.
F) Stand the cylinder for 1 minute and check the foaming state to determine the foaming property.
The determination was made according to the following criteria.

○: No bubbles on the wall surface, with no bubbles, or almost no bubbles are noticeable and thin streaky bubbles remain on the liquid surface.
X: The layer which can be recognized as a bubble clearly is formed on the liquid level, and the bubble adheres also to the wall surface of the cylinder.

(10) Qualitative measurement evaluation of fallen fiber After putting a sample in pure water and washing with an ultrasonic cleaner, the pure water is filtered, and the amount of fiber remaining on the filter paper (large or small) is sensoryly determined. Evaluation methods and criteria are as follows.
Evaluation method: A 25 cm × 25 cm sample is prepared and put into a 500 ml beaker containing 300 ml of pure water. Place water in the BRANSON B2210 ultrasonic cleaner to operating level and a 500 ml beaker with sample. After washing with an ultrasonic cleaner for 15 minutes, it is filtered with black filter paper (ADVANTEC NO131). After putting in a thermostatic chamber (20 ° C., 65% RH) for 12 hours and drying, the sensory evaluation is performed.

Judgment criteria ○: There is almost no lint on the black filter paper.
(Triangle | delta): The thread waste remaining on the black filter paper is conspicuous.
X: Waste thread enough to disappear the color of the black filter paper remains.

(11) Sensory evaluation of workability A work table of 60 cm × 90 cm is prepared. Evaluation is performed on a sample obtained by folding a 25 cm × 25 cm non-woven fabric into four.
B) Dry evaluation: The entire work table and the end of the work table were wiped off as they were, and the workability was evaluated according to the following criteria.
B) Water absorption evaluation: 10 cc of distilled water was spilled on the center of the workbench, wiped with a sample, and workability was evaluated according to the following criteria.
C) Evaluation by wet: In a state where distilled water of 250% of the mass of the sample was added to the sample, the entire surface of the workbench and the end of the workbench were wiped off, and workability was evaluated according to the following criteria.

Evaluation criteria (including wipeability, water absorption, wiping residue, wiper condition, etc.)
5: Workability is very good.
4: Good workability.
3: Normal workability.
2: Workability is poor.
1: Workability is extremely poor.

The average value of the evaluation of (i), (b), and (c) was regarded as workability, and the total average was carried out with 20 monitors, and workability was evaluated according to the following criteria.
○: Workability average value of 3.5 or more.
Δ: Workability average value of 2.5 or more and less than 3.5.
X: Workability average value is less than 2.5.
In addition, if a special event occurred, a comment was added.

[Example 1]
Cotton linter was dissolved with a copper ammonia solution to prepare a spinning dope having a cellulose concentration of 10 wt%. The stock solution was extruded at a rate of 3.4 cc / cm ² · min per unit area of the spinneret from a rectangular spinneret having a diameter of the stock solution discharge hole of 0.3 mm and a number of holes of 180 pieces / cm ² . The extruded stock solution was introduced into a rectangular one-stage funnel together with spinning water, and stretched simultaneously with coagulation by deammonification. At this time, the temperature of the spinning water was 35 ° C., the flow rate per unit area of the spinneret was 540 cc / cm ² · min, and the speed of the solidified yarn was 110 m / min.

  The web was obtained by vibrating the net in a direction perpendicular to the net traveling direction while shaking the fibers formed by solidification onto the net having a mesh structure capable of passing liquid. At this time, the speed of the net was 25 m / min, the vibration width was 22% with respect to the width of the spinneret, and the number of vibrations was 320 times / min. Four layers of webs spun under the same conditions were stacked on the obtained one-layer web, and finally a five-layer cellulose continuous long fiber web was obtained. The obtained cellulose continuous long fiber web was regenerated with dilute sulfuric acid, washed with water, and the obtained regenerated cellulose continuous long fiber web was entangled with fibers at a high pressure water flow of 3 MPa on a 20 mesh sheet, and then 100 ° C. Drying with hot air was performed to obtain a regenerated cellulose continuous long fiber nonwoven fabric having through holes and recesses formed on the surface.

The obtained regenerated cellulose continuous long-fiber nonwoven fabric has a basis weight of 29.0 g / m ² , a thickness of 0.22 mm, and the number ratio of fibers having a fiber diameter of 2.9 to 7.1 μm constituting the nonwoven fabric surface is 100%. The fiber arrangement coefficient was 0.81. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber nonwoven fabric has good wiping properties, excellent shape retention when wet, white without bleaching, little yellowing even after steam sterilization, There were few impurities, few fallen fibers, good workability, and it was extremely excellent as a wiper for clean rooms.

[Example 2]
In the method described in JP-T-2002-521585, the diameter of the stock solution discharge hole was set to 30 μm, and other conditions were obtained using appropriate conditions. The basis weight of the obtained cellulose continuous fiber nonwoven fabric is 26.5 g / m ² , thickness 0.21 mm, and the ratio of the number of fibers with a fiber diameter of 2.9 to 7.1 μm constituting the nonwoven fabric surface is 89%, The fiber alignment factor was 0.90. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained cellulose long fiber nonwoven fabric has good wiping properties, excellent shape retention when wet, white without bleaching, little yellowing even after steam sterilization, and impurities. Although there were few falling fibers, the workability was good and the wiper for a clean room was extremely excellent.

[Example 3]
The stock solution was extruded at a rate of 3.4 cc / cm ² · min per unit area of the spinneret from a rectangular spinneret having a diameter of the stock solution discharge hole of 0.3 mm and a number of holes of 180 pieces / cm ² . The temperature of the spinning water was 38 ° C., the flow rate per unit area of the spinneret was 350 cc / cm ² · min, and the speed of the solidified yarn was 44 m / min. At this time, the speed of the net was 25 m / min, and the number of vibrations was 260 times / min. Under the same conditions as in Example 1, a regenerated cellulose continuous long fiber nonwoven fabric having through holes and recesses formed on the surface was obtained.

The obtained regenerated cellulose continuous long-fiber nonwoven fabric has a basis weight of 23.2 g / m ² , a thickness of 0.19 mm, and the number ratio of fibers having a fiber diameter of 2.9 to 7.1 μm constituting the nonwoven fabric surface is 100%. The fiber arrangement coefficient was 0.68. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber non-woven fabric has good wiping properties, is white even without bleaching, slightly inferior in yellowing by steam sterilization, slightly reduces the shape retention when wet, Although there were some problems in workability, there were few impurities, there were few falling fibers, and it was excellent as a wiper for clean rooms.

[Example 4]
Diameter 0.6mm stock solution discharge hole, a rectangular spinneret having 45 pieces / cm number of holes ^2, extruded stock at per unit area 3.4cc ^/ cm 2 · min of spinneret, stacked in three layers A web was formed. To the resulting 3-layer web on the diameter 0.3mm stock solution discharge hole, a rectangular spinneret having 180 / the number of holes cm ^2, to 3.4cc ^/ cm 2 · min per unit area of spinnerette Then, the stock solution was extruded, and two layers of webs were laminated, and finally a cellulose continuous long fiber web of five layers was formed. Except for the above, under the same conditions as in Example 1, a regenerated cellulose continuous long-fiber nonwoven fabric having through-holes and recesses formed on the surface was obtained.

The obtained regenerated cellulose continuous long-fiber non-woven fabric has a basis weight of 27.5 g / m ² and a thickness of 0.32 mm, and the ratio of the number of fibers having a fiber diameter of 2.9 to 7.1 μm constituting the non-woven fabric surface is 66%. The fiber arrangement coefficient was 0.76. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long-fiber nonwoven fabric has good wiping properties, is white without bleaching, has good yellowing by steam sterilization, and has good shape retention and workability when wet. Therefore, it has few impurities and few falling fibers, and is extremely excellent as a wiper for a clean room.

[Example 5]
A spinneret having a diameter of the stock solution discharge hole of 0.2 mm is used, the temperature of the spinning water is 25 ° C., the flow rate per unit area of the spinneret is 600 cc / cm ² · min, the speed of the solidified yarn is 120 m / min, A regenerated cellulose continuous long-fiber nonwoven fabric having through-holes and recesses formed on the surface was obtained under the same conditions as in Example 1 except that the speed was 15 m / min.

The obtained regenerated cellulose continuous long-fiber nonwoven fabric has a basis weight of 38.7 g / m ² , a thickness of 0.24 mm, and the number ratio of the fibers having a fiber diameter of 2.9 to 7.1 μm constituting the nonwoven fabric surface is 89%. The fiber arrangement coefficient was 0.79. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber nonwoven fabric has good wiping properties, excellent shape retention when wet, white without bleaching, little yellowing even after steam sterilization, There were few impurities, few fallen fibers, good workability, and it was extremely excellent as a wiper for clean rooms.

[Example 6]
In accordance with the method described in US Pat. No. 4,346,221 and US Pat. No. 4,416,698, long fibers were spun with the diameter of the stock solution discharge hole set to 80 μm. The obtained long fibers had an average fiber diameter of 6.9 μm. The obtained long fibers were cut to a length of 50 mm, formed into a web with a card, and the cross-laid web was entangled with a high-pressure water stream to obtain a cellulose short fiber nonwoven fabric.

The obtained cellulose short fiber nonwoven fabric has a basis weight of 42.2 g / m ² , a thickness of 0.32 mm, and the ratio of the number of fibers having a fiber diameter of 2.9 to 7.1 μm constituting the nonwoven fabric surface is 100%. The arrangement coefficient was 0.73. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber nonwoven fabric has good wiping properties, excellent shape retention when wet, white without bleaching, little yellowing even after steam sterilization, Although there are few impurities and there is a tendency to have a little amount of fallen fibers, the workability is good and the cleanliness is low (class 10,000 to 100,000).

[Comparative Example 1]
In Example 1, a regenerated cellulose continuous long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the speed of the net for shaking off the web was 3.8 m / min and the number of vibrations was 500 times / min. The obtained regenerated cellulose continuous long-fiber non-woven fabric is 100% in terms of the number ratio of fibers having a basis weight of 191.5 g / m ² , a thickness of 0.93 mm, and a fiber diameter of 2.9 to 7.1 μm constituting the non-woven fabric surface. The sequence coefficient was 1.90. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber non-woven fabric has some densely packed single fibers on the surface, is inferior in appearance, is very hard and has poor workability, and cannot be used as a wiper for a clean room It was a level.

[Comparative Example 2]
In Example 1, continuous regenerated cellulose was produced in the same manner as in Example 1 except that the speed of the net for shaking off the web was 45.7 m / min, the number of laminated webs was 3, and the number of vibrations was 100 times / min. A long fiber nonwoven fabric was obtained. The obtained regenerated cellulose continuous long-fiber non-woven fabric has a fiber ratio of 92%, with a basis weight of 7.5 g / m ² , a thickness of 0.04 mm, and a fiber diameter of 2.9 to 7.1 μm constituting the non-woven fabric surface. The arrangement coefficient was 0.60. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long fiber non-woven fabric was very hard and poor in workability such as tearing in the machine axis direction at the time of operation, and was at a level that could not be used as a clean room wiper.

[Comparative Example 3]
The web produced with a stock solution discharge hole diameter of 0.6 mm (stock solution discharge amount of 4 cc / cm ² · min per unit area of the spinneret) is made into four layers, and the stock solution discharge hole diameter of 0.3 mm (per unit area of the spinneret) Regenerated cellulose continuous long fiber with through-holes and recesses formed on the surface under the same conditions as in Example 4 except that the web produced by 3.4 cc / cm ² · min. A nonwoven fabric was obtained.

The obtained regenerated cellulose continuous long-fiber nonwoven fabric has a fiber number ratio of 56%, in which the fiber having a basis weight of 30.3 g / m ² , a thickness of 0.33 mm, and a fiber diameter of 2.9 to 7.1 μm constitutes the nonwoven fabric surface. The arrangement coefficient was 0.73. The evaluation results of characteristics and functionality are shown in Tables 1 and 2.
As can be seen from the table, the obtained regenerated cellulose continuous long-fiber nonwoven fabric has a change in form when used in a roll shape, compared with the nonwoven fabric obtained in the examples, and there is a problem in workability, wiping property, whiteness. Inferior in form retention when wet, there was a problem in using as a wiper for a clean room as compared with the product of the present invention.

  As can be seen from the above results, the wiper for a clean room of the present invention has extremely excellent characteristics in various wiping operations in a clean room in which the environment is controlled.

  The wiper for a clean room of the present invention has good wiping property, shape retention property when wet, water absorption, antistatic property, chemical resistance, elution from wiper when impregnated with solvent, minute dust, dust, fibrous There are very few occurrences of scraps, material fragments, etc., whiteness required for specific applications, yellowing due to steam sterilization has been improved, and it is represented by large-scale integrated circuits, electronic equipment, electronic components, liquid crystals, optical systems, etc. For clean rooms used in environmentally controlled clean rooms and processes that are often installed in manufacturing processes for precision mechanical parts and electronic parts, manufacturing processes for pharmaceuticals, medical devices, etc., aseptic rooms, food-related manufacturing processes, etc. It can be suitably used as a wiper.

It is a figure which shows typically the measuring method of a fiber arrangement coefficient and a diffusion area. It is a figure which shows typically the measuring method of a wet form retention rate.

Explanation of symbols

1 ... Stand 2 ... Sample holding plate (fixed with two samples sandwiched between them)
3 ... Sample 4 ... Load

Claims (2)

Regenerated cellulose continuous long fibers having a fiber diameter 2.9~7.1μm is, accounting for over 60% of the number of fibers on one side surface of at least a nonwoven fabric, and regenerated cellulose continuous fiber array factor is 0.65 to 1.35 Clean room wiper using non-woven fabric of long fibers . Regeneration Cellulose continuous length nonwoven wet form retention of the fibers is 80% or more, clean room wiper according to claim 1.

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