JP2007303022A - Laminated fifer structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiper which is used for cleaning screens, has high antistaticity, does not deteriorate strength even in a wet state, and has a high wiping performance. <P>SOLUTION: This laminated fiber structure is characterized in that at least a first layer comprises a cellulosic fiber nonwoven fabric having opened holes in the surface, and has a hole area of 0.05 to 0.5 mm<SP>2</SP>/hole, a number of holes of 10 to 100 holes/2.54 cm<SP>2</SP>(6.45 cm<SP>2</SP>), and a frictional charge voltage of <700 V; a second layer and the other layers include cellulosic fiber structures, synthetic fiber structures, or the like; and the laminated fiber structure has a tensile strength of 50 to 300 N/50 mm, when wetted, and an air permeability of 50 to 250 cc/cm<SP>2</SP>/sec. And the wiper for a screen printing machine uses the laminated fiber structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated fiber structure, and more particularly to a laminated fiber structure made of a cellulosic fiber nonwoven fabric.

  Currently, when manufacturing electrical parts, electronic parts, and IC-related parts, a screen printer is used to print cream solder on a printed wiring board. However, cream solder remains gradually on the opening and the back surface of the screen due to irregularities on the surface of the printed wiring board and other factors. If printing is continued with the remaining solder left unattended, the print quality will deteriorate, so it is common to periodically suck and clean the remaining cream solder on the screen. Many wipers are mainly used which are made of non-woven fabrics made of cellulosic fibers, which are less charged to the screen due to contact friction during removal.

However, recent improvements in the density of the above-mentioned electrical parts, electronic parts, IC-related parts and cream solder, increased wiping cleaning under wet conditions using a solvent such as isopropyl alcohol, increased operating speed of the printing press, compact size In addition to the above performance, a wiper for screen cleaning that does not decrease in strength even in a wet state and has higher wiping performance is desired.
As a wiper for cleaning using a cellulosic fiber nonwoven fabric, for example, there is a spunlace nonwoven fabric (described in Patent Document 1) consisting essentially of an aggregate consisting of wood pulp and synthetic organic fibers. When wiping a creamy solder having a large viscosity of about 10 to 40 μm, such a non-perforated type of wiper does not allow the solder to be sucked and is simply stretched to the screen surface.

In addition, there is a method for manufacturing a patterned spunlace fabric (described in Patent Document 2). However, if the spunlace fabric is simply perforated, many through-holes are formed. Solder and solvent at the time of wet wiping pass through and damage the printing machine, or the solder falls from the holes and reattaches to the screen.
For this reason, it has been extremely difficult to produce a wiper for screen cleaning that has high antistatic properties, does not deteriorate in strength even in a wet state, and has high wiping performance.
Japanese Patent Publication No. 3-73665 JP 2002-161463 A

  An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a wiper for screen cleaning that has high antistatic properties, does not deteriorate in strength even in a wet state, and has high wiping performance.

As a result of intensive studies on the above-mentioned problems, the present inventors have invented a wiper having no proper solder diameter and no solder penetration by having an appropriate hole diameter, area, air permeability, and thickness. .
That is, the invention claimed in the present application in order to achieve the above-described problems is as follows.
(1) At least the first layer is made of a cellulosic fiber unwoven cloth having an open surface, the area of the holes is 0.05 to 0.5 mm ² / piece, and the number of holes is 10 to 100 pieces / 2.54 cm. Square (6.45 cm ² ), friction band voltage less than 700 V, the second and subsequent layers are composed of a fibrous structure such as cellulosic fiber or synthetic fiber, and the tensile strength when the laminated structure is wet is 50 to 300 N / 50 mm, The air permeability is 50 to 250 cc / cm ² / sec. The laminated fiber structure characterized by being.
(2) The laminated fiber structure according to (1), wherein the total thickness is 0.10 to 0.60 mm.
(3) A wiper for a screen printing machine using the laminated fiber structure according to (1) or (2).

  The laminated structure made of cellulosic fiber nonwoven fabric obtained by the present invention can provide a wiper for screen cleaning that has high antistatic properties, does not deteriorate in strength even in a wet state, and has high wiping performance.

The present invention is described in detail below.
Cellulosic fibers in the present invention are natural cellulose fibers such as hemp and cotton, regenerated cellulose fibers such as cupra, viscose rayon and polynosic rayon (especially preferably having an average polymerization degree of 500 to 600), lyocell, (Journal of the Textile Society of Japan) (Fiber and industry) Vol. 48, No. 11 (1992) P. 584 to P. 591 are equivalent to the product name Tencel of Coatles Co.), etc., preferably fiber Among them, regenerated cellulose fibers and purified cellulose fibers with few impurities are contained, and more preferably regenerated cellulose continuous long fibers that are less prone to fall off fibers.

  The cellulosic fiber nonwoven fabric of the present invention is mainly composed of cellulosic fibers. Cellulosic fibers may be 100%, and synthetic fibers such as polyester and polyamide may be mixed in a range satisfying the frictional voltage described in the present invention. In this case, the content of cellulosic fibers in the fiber structure is preferably 30% by weight or more, more preferably 50% by weight or more, and still more preferably 70% by weight or more. Moreover, the structure of unemployed cloth, single yarn denier, etc. are not particularly limited.

  Although the structure of the cellulose fiber nonwoven fabric of this invention is not specifically limited, It is preferable that a cellulose fiber exists with an area ratio of 50% or more at least on the surface in contact with the screen. The area ratio referred to here is the area ratio of the cellulosic fibers present on the surface. For example, when compounded with synthetic fibers, the cellulosic fibers are dyed, and the structure is dyed with a dye that does not dye the synthetic fibers, The area of the stained portion relative to the surface area can be obtained by image analysis or the like. When the cellulosic fiber area ratio on both surfaces is less than 50%, particularly when the wiper is used in a dry state, it is difficult to obtain an antistatic performance that satisfies the above-described structural requirements.

The manufacturing method of a cellulosic fiber nonwoven fabric is not specifically limited. For example, it may be made by a wet method, a dry method, a papermaking method, or a composite of these.
An example is introduced about the manufacturing method of the cellulose fiber nonwoven fabric of this invention. A preferred embodiment of the present invention is a regenerated cellulose continuous long-fiber nonwoven fabric. For example, a cupra nonwoven fabric “Benlyse (registered trademark)” manufactured by Asahi Kasei Fibers Corporation 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 extruded from a spinneret (spinner) having pores (stock solution discharge holes), together with water. The funnel is dropped and deammoniated to solidify the stock solution, and then stretched and sprinkled onto a net to form a web. At this time, the fiber shaken down to the net draws a Sin curve by vibrating in the direction perpendicular to the traveling direction while the net is moving. 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, which remains in the stock solution by changing the amount of spinning water and temperature. Further, by controlling the traveling speed and vibration width of the net, it is possible to control the fiber arrangement direction and to control the strength and elongation as a 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 in the present invention is preferably 0.1 to 0.5 mm, and the shape is preferably a round shape. 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. The laminated web is regenerated or scoured with cellulose in a web state by, for example, a method described in Japanese Patent Nos. 787914 and 877579, and then a nonwoven fabric is produced by entanglement of fibers with a high-pressure water stream. 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 under 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.

Basis weight of the cellulosic fiber nonwoven fabric of the present invention, in terms of meeting the frictional electrification voltage of requirements it is preferably 8~150g / ^{m 2,} more preferably from 10~120g / ^{m 2.}
In the laminated fiber structure of the present invention, the cellulosic fiber unwoven cloth present in at least the first layer has an open surface, and the area of the hole is 0.05 to 0.5 mm ² / piece, preferably Is 0.06 to 0.4 mm ² / piece, more preferably 0.09 to 0.25 mm ² / piece. The number of holes is 10 to 100 / 2.54 cm ² (6.45 cm ² ), preferably 20 to 50 / 2.54 cm ² (6.45 cm ² ), more preferably 30 to 40. /2.54 cm square (6.45 cm ² ).

If the area and number of the holes are larger than the above range, there is a risk that solder, solvent, etc. may enter the device as described above. Conversely, if the area or number is smaller than the above range, solder is not taken into the structure, and as a result, the remaining wiping of the solder occurs.
The method of opening the hole is not particularly limited as long as it satisfies the above range. However, a method using a high-pressure liquid flow such as a water jet is preferable in that the generation of dropped fibers is small. Specifically, a non-woven fabric is placed on a mesh-like net made of stainless steel, phosphor bronze, etc., and holes having the same number as the mesh of the net can be opened by performing high-pressure liquid flow treatment from above. . The area of the hole can be adjusted according to the opening ratio of the net, high-pressure liquid flow treatment conditions, etc., and the net supporting the cellulosic fiber unwoven cloth is used to obtain the hole area of the unwoven cloth of the present invention. It is preferably 25 to 45%, more preferably 30 to 43%.

  In addition, the cellulosic fiber nonwoven fabric of the present invention is more preferable in terms of cream solder wiping performance as long as it is surface-modified such as a pattern formed by recesses, irregularities and the like in addition to holes. The shape of the concave portion and the mesh pattern may be appropriately selected depending on usage within the range satisfying the above-described configuration requirements. Such a surface modification can be suitably obtained by processing with a high-pressure liquid flow such as the water jet, and the nonwoven fabric fibers on the entanglement points of the net are pushed to the surroundings by the high-pressure liquid flow. it can. Further, for example, a method of forming a concavo-convex pattern on the surface of a metal roll and applying a concavo-convex shape through a nonwoven fabric while applying pressure between the metal roll and the rubber roll can be suitably obtained.

The friction band voltage in the present invention refers to the friction band voltage in the JIS-1094 method. In the case of the laminated fiber structure of the present invention, it is less than 700 V, preferably 50 to 500 V, more preferably 50 ~ 300V. In the case of a friction band voltage of 700 V or more, the solder may be charged during wiping, and may be adsorbed on the screen, resulting in wiping failure. The greater the amount of cellulose present on the surface, the lower the friction withstand voltage, which is preferable.
In the present invention, the fiber structure such as a synthetic fiber used in the second layer and after is a fiber such as cellulosic fiber, polyester, polyamide, polypropylene, polyethylene, etc., particularly preferably polyester, polyamide, polypropylene, and more preferably polyester. is there.
The form of the fiber structure may be any form such as a woven or knitted fabric, a nonwoven fabric, or cotton, but is preferably a knitted fabric or a nonwoven fabric, more preferably a long fiber nonwoven fabric.
The fiber structure, single yarn denier, and the like are not particularly limited as long as they satisfy the constituent requirements of the present invention after lamination.

In the lamination method of the laminated structure of the present invention, it is preferable not to use a binder that elutes into a hydrophilic or hydrophobic solvent, but to use a composite with high-pressure fluid such as a water jet or pressure bonding by embossing. Further, in the case of compounding with a water jet, it is preferable that no through hole is opened after lamination in order to prevent the solder from getting through after compounding.
The number of layers of the laminated structure of the present invention is not particularly limited as long as it is 2 or more as long as it satisfies the constituent requirements of the present invention after lamination, but preferably 2 to 8, more preferably 2 to 5 sheets.
For the purpose of satisfying the constituent requirements of the present invention, a method for adjusting the thickness such as mangle treatment after lamination can be used as appropriate.
In the laminated structure of the present invention, the thickness of the entire laminated body is preferably 0.10 to 0.60 mm, more preferably 0.15 to 0.50 mm so that the cream solder does not pass through during wiping. More preferably, it is 0.25 to 0.40 mm. If the thickness is less than 0.25 mm, solder or solvent may come through, and conversely if the thickness is greater than 0.40 mm, there is a possibility that poor incorporation of solder into the laminated structure may occur due to a decrease in air permeability. is there.

As described above, the vacuum solder is often used together with the vacuum solder, so that the laminated structure has an air permeability of 50 to 250 cc / cm ² / sec. In a Frazier type air permeability tester according to the JIS-L1096 method. Need to be. Preferably it is 100-230cc / cm < ² > / sec. More preferably, it is 150-220 cm < ² > / sec. It is. 50 cc / cm ² / sec. If it is less than that, there is a high possibility that the solder will be insufficiently sucked, resulting in poor wiping. Conversely, 250 cc / cm ² / sec. Then, there is a high possibility that the solder and the solvent will penetrate the laminated structure and enter the equipment, resulting in damage to the equipment.

In the laminated fiber structure of the present invention, in order to achieve the above-mentioned air permeability, for example, it can be suitably obtained by setting the water pressure at the time of opening a hole in the structure by a high-pressure water flow to 0.5 to 5.0 MPa.
Furthermore, as described above, the wiping of the cream solder is often performed under wet conditions using a solvent such as isopropyl alcohol, and the tensile strength of the laminated structure when wet is determined by the tensile strength and elongation according to JIS-L1096 method. The tensile strength by the tensile strength / elongation measuring apparatus used in the measurement is 50 to 300 N / 50 mm, preferably 80 to 200 N / 50 mm. If it is less than 50 N / 50 mm, the laminated structure is likely to be broken during wiping. Conversely, a tensile strength of 300 N / 50 mm or more is not necessary in the present invention. In the laminated fiber structure of the present invention, the tensile strength when wet can give preferable performance by appropriately selecting the material, shape and basis weight of the unwoven cloth to be laminated. For example, when using a polyester continuous long fiber nonwoven fabric (ELTAS (registered trademark), manufactured by Asahi Kasei Fibers Co., Ltd.), use a polyester continuous long fiber nonwoven fabric having a basis weight of 15 to 70 g / m ^2. Etc. are suitably obtained.

The form of the wiper in 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.
The wiper of the present invention may have, for example, a long winding shape, that is, a roll shape. The roll-shaped wiper is preferably used particularly for a fully automatic screen printer or continuous wiping. The winding length, width, and the like are not particularly limited, and may be appropriately selected depending on the application.

Further, in the wiper of the present invention, various functions can be arbitrarily added that can be additionally given to the wiper as long as the object of the present invention is not impaired.
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, those having a size of 7.62 to 30.48 cm (3 to 12 inches) are 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 common.

The packaging form, packaging material, and the like of the 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. The packaging material is not particularly limited as long as it does not inhibit the target performance, but it is more preferable to use a bag having antistatic performance. Since static electricity is generated by friction between objects, it is more 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 of about 10 ⁶ to 10 ¹⁰ Ω / cm ² .

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Moreover, evaluation of the processed material in an example was performed as follows.
(1) Hole area / number of holes The obtained laminated fiber structure was observed using a video microscope (VHX-500, manufactured by Keyence Corporation), and 2.54 cm square (6.45 cm ²⁾ from the obtained hole image. ) Measure the number of holes per unit. The hole area was measured by an elliptical area formula (formula 1 below), assuming that each hole is an ellipse, where a is the radius of the major axis of the ellipse and b is the radius of the minor axis.
Pore area = πab (1)
(2) Friction band voltage The obtained laminated fiber structure was measured by a rotary static tester under the conditions of a temperature of 20 ° C. and a relative humidity of 40% RH in accordance with a friction band voltage measurement method based on JIS-1094.
(3) Laminate thickness The obtained laminated fiber structure was measured with a load of 1.96 kPa in a thickness test in accordance with JIS-L1096.

(4) Air permeability The obtained laminated fiber structure was evaluated using a Frazier type tester by a gas permeability test method based on JIS-L1096.
(5) Tensile strength when wet The obtained laminated fiber structure was measured in an environment of a temperature of 20 ° C. and a humidity of 65 RH% using a universal tensile strength / elongation measuring machine Tensilon RTM-100 (manufactured by Orientec Corporation). .
(6) Wiping performance Using the SP80V-M (Panasonic Factory Solutions screen printer), the stainless steel (SUS304) screen (caliber 0.5 mm, 0. 1 mm thick) is filled with cream solder (with a viscosity of 200 Pa.S containing solder balls with a particle size of 30 μm), a vacuum pressure of 0.05 MPa, and a wiping speed of 50 mm / min. A wiping test was conducted under dry conditions, and the wiping performance was graded as shown in Appendix 1.

[Example 1]
A regenerated cellulose continuous long fiber nonwoven fabric (Benlyse (registered trademark), manufactured by Asahi Kasei Fibers Co., Ltd.) having an average basis weight of 27.5 g / m ² was prepared. On an SUS304 mesh with an aperture of 40 pieces / 2.54 cm square (6.45 cm ² ) (a porosity of 36%), a polyester continuous long fiber non-woven fabric having an average basis weight of 20 g / m ² (ELTAS (registered) (Trademark), manufactured by Asahi Kasei Fibers Co., Ltd.), and one Benize was placed thereon. Next, at a water pressure of 5.0 MPa, 20 m / min. A high-pressure water flow treatment was performed at a speed of 2 mm, and the two unclothed cloths were entangled and then dried at 100 ° C.
Table 2 shows the physical properties of the obtained laminated structure. As a result of the evaluation test, a layered structure having a wiping property of the structure, a very good wiping property without any back-through, a high tensile strength when wet, and a low frictional voltage is obtained. It was.

[Example 2]
In Example 1, the treatment was performed under the same conditions as in Example 1 except that a mesh made of SUS304 having a hole of 30 pieces / 2.54 cm square (6.45 cm ² ) at the time of lamination (41% porosity) was used. Went. Table 2 shows the physical properties of the obtained laminated structure. As a result of the evaluation test, there was obtained a laminated structure having a wiping property of the structure, a good wiping property with little streak, high tensile strength when wet, and low frictional voltage. .

[Comparative Example 1]
Evaluation was performed using a pulp / polyester composite spunlace wiper having an average basis weight of 70 g / m ² , a laminate thickness of 0.30 mm, a hole area of 0.18 mm ² and a number of holes of 40 / 2.54 cm ² (6.45 cm ² ). A test was conducted. As a result of the evaluation test, the wiping property did not show through, but the remnant of the solder on the screen due to electrification caused linear streaks.

[Comparative Example 2]
In Example 1, treatment was performed under the same conditions as in Example 1 except that a mesh made of SUS304 (opening ratio 20%) having 120 holes / 2.54 cm square (6.45 cm ² ) holes was used at the time of lamination. Went. Table 2 shows the physical properties of the obtained laminated structure. As a result of the evaluation test, although the wiping property of the structure was almost no see-through, streaks remained on the surface.

[Comparative Example 3]
In Example 1, treatment was performed under the same conditions as in Example 1 except that a mesh made of SUS304 (opening ratio 47%) having 8 holes / 2.54 cm square (6.45 cm ² ) at the time of lamination was used. Went. Table 2 shows the physical properties of the obtained laminated structure. As a result of the evaluation test, there was almost no streak remaining in the wiping property of the structure, but solder break-through occurred in a narrow range and entered the device.

  According to the present invention, it is possible to provide a wiper for screen cleaning that has high antistatic properties, does not deteriorate in strength even in a wet state, and has high wiping performance.

Claims (3)

At least the first layer is made of a cellulosic fiber unwoven cloth having a surface opened, the area of the hole is 0.05 to 0.5 mm ² / piece, the number of holes is 10 to 100 pieces / 2.54 cm square (6 .45 cm ² ), friction band voltage of less than 700 V, the second and subsequent layers are composed of fiber structures such as cellulosic fibers or synthetic fibers, the laminated structure has a tensile strength when wet of 50 to 300 N / 50 mm, and air permeability. 50 to 250 cc / cm ² / sec. The laminated fiber structure characterized by being.   The laminated fiber structure according to claim 1, wherein the total thickness is 0.10 to 0.60 mm.   A wiper for a screen printing machine using the laminated fiber structure according to claim 1 or 2.