JP2021074893A - Combination screen plate - Google Patents

Abstract

To provide a combination screen plate that can prevent electrification.SOLUTION: A combination screen plate (100) has a screen for image formation (102) for holding ink and forming an image, and a screen for support (103) that is fixed to the screen for image formation (102) and a frame (101), thereby supporting the screen for image formation (102). The screen for support (103) has a surface resistivity of 1×1011[Ω/sq] or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a combination screen plate for screen printing.

Conventionally, in screen printing equipment, the function of removing static electricity is not always sufficient, and static electricity generated by squeezing is not completely removed and accumulates in the mask plate, causing the mask plate to be charged to a high potential. There is. If screen printing is performed while the mask plate is charged, if electronic components are already mounted on the substrate to be printed, these electronic components may be damaged. When electronic components are not mounted on the substrate to be printed, these substrates are sent to the subsequent process in a state of being charged by the electric charge conducted from the mask plate, and the electronic components mounted here are sent. May cause damage.

For example, even in a so-called combination screen printing plate in which a conductive screen is used instead of a metal mask and a photosensitive resin is applied to substantially the entire surface of the conductive screen to form a desired opening pattern, it occurs during squeezing. The generated static electricity may be charged. Due to this effect, for example, a phenomenon in which printed matter such as ink or paste scatters during screen printing and adheres to unnecessary parts of the printed matter (a phenomenon called "scattering") occurs, or screen printing causes the printed matter to be printed on the printed matter. When a phenomenon in which whiskers grow around printed matter such as patterned ink or paste (a phenomenon called "whisker" or "threading") occurs, which causes printing defects. There is. Therefore, even in the combination screen printing plate, it is indispensable to prevent printing defects caused by electrostatic charging.

For example, the combination screen printing plate described in Patent Document 1 is disclosed as a solution to a printing defect caused by electrostatic charging as described above. In this combination screen printing plate, one end of the conductive material (conductive tape) is attached to the conductive screen without passing through the photosensitive resin layer, and the other end of the conductive material (conductive tape) is attached to the conductive screen. It is pasted on the frame.

Japanese Unexamined Patent Publication No. 2019-051664

However, in Patent Document 1, since the conductive material (conductive tape) must be attached to each of the conductive screen and the conductive screen frame, this attaching operation is troublesome. Further, when the conductive material (conductive tape) is attached, the conductive material (conductive tape) may be peeled off while the combination screen printing plate is being used continuously. In Patent Document 1, in order to prevent the conductive material (conductive tape) from peeling off, a protective tape is attached so as to cover the conductive material (conductive tape). In this case, the protective tape is attached. It takes time and effort to paste.

An object of the present invention is to provide a combination screen plate capable of preventing charging of an image forming screen that forms an image of a print pattern without performing a pasting operation as in Patent Document 1.

The combination screen plate of the present invention includes an image forming screen for holding ink and forming an image, and a supporting screen for supporting the image forming screen by being fixed to the image forming screen and the frame. Has. The surface resistivity of the supporting screen is 1 × 10 ¹¹ [Ω / □] or less.

The surface resistivity of the supporting screen can be 1 × 10 ² [Ω / □] or more and 1 × 10 ¹¹ [Ω / □] or less.

The image forming screen can be made of metal.

It is preferable that the surface resistivity Ri [Ω / □] of the image forming screen and the surface resistivity Rо [Ω / □] of the supporting screen satisfy the conditions shown in the following formula (I).
1 × 10 ⁷ ≦ Ri × Rо ≦ 1 × 10 ¹¹ ... (I)

According to the present invention, it is possible to provide a combination screen plate capable of preventing charging of an image forming screen.

It is a schematic diagram of the combination screen version.

The combination screen version according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a combination screen version. The combination screen plate 100 of the present embodiment is used for screen printing and has a frame 101, an image forming screen 102, and a supporting screen 103. Screen printing includes, for example, phosphor printing during PDP (Plasma Display Panel) manufacturing, solar cell electrode printing, liquid crystal seal printing, substrate fill-in-the-blank printing, capacitor electrode and dielectric printing, TAB (Tape Automated Bonding) and It is used in the field of precision pattern formation such as electronics related printing such as resist printing such as COF (Chip On Film).

The frame 101 is used to apply tension to the image forming screen 102 and the supporting screen 103, and is attached to a screen printing machine. The structure of the frame 101 may be a solid structure or a hollow structure. When the hollow frame 101 is used, the strength of the frame 101 can be improved by increasing the wall thickness of the frame 101 or providing a reinforcing member such as a rib.

The material of the frame 101 is not particularly limited, and for example, wood, resin, and metal can be used, and examples of the metal include aluminum, aluminum alloy, steel, and iron alloy. Here, an aluminum alloy can be used in consideration of weight reduction, high strength, chemical resistance, and ease of processing. As will be described later, static electricity from the image forming screen 102 flows through the frame 101, and the frame 101 is grounded. When the material of the frame 101 is a material such as wood or resin in which electricity does not easily flow, it is preferable to secure a path for releasing static electricity from the image forming screen 102.

The image forming screen 102 is arranged in the center of the combination screen plate 100 and has a plurality of holes for holding ink used for forming an image. The image forming screen 102 may be configured as a mesh woven fabric or a sheet as long as it has the above-mentioned ink holding holes. As the material of the image forming screen 102, a metal or a resin containing a conductive material can be used, and a metal is preferable from the viewpoint of printing accuracy. As will be described later, the present embodiment is intended to prevent charging of the image forming screen 102, so that the image forming screen 102 is formed of a charged material.

When the image forming screen 102 is configured as a mesh woven fabric, a metal wire rod can be used, or a resin fiber or a glass fiber can be used. Examples of the metal include stainless steel, tungsten, nickel, and high-strength steel. Further, as the resin, for example, plastic can be used. When the image forming screen 102 is configured as a sheet, a plurality of holes may be formed in the base material of the sheet. For example, when a metal sheet is used, a plurality of holes can be formed by etching treatment, laser treatment, or electroforming method.

The support screen 103 supports the image forming screen 102. Specifically, the support screen 103 is formed in a frame shape, the inner edge portion of the support screen 103 is fixed to the outer edge portion of the image forming screen 102, and the outer edge portion of the support screen 103 is fixed. It is fixed to the frame 101. When screen printing is performed using the combination screen plate 100, the support screen 103 expands and contracts so that the image forming screen 102 can be aligned with the printing surface. As a result, the ink held on the image forming screen 102 can be transferred to the printing surface while the image forming screen 102 is aligned with the printing surface, and the printing accuracy can be ensured.

The surface resistivity (also referred to as sheet resistance) Rо of the support screen 103 is higher than the surface resistivity Ri of the image forming screen 102 and is 1 × 10 ¹¹ [Ω / □] or less. By setting the surface resistivity Rо of the support screen 103 to 1 × 10 ¹¹ [Ω / □] or less, it is possible to easily release the static electricity generated in the image forming screen 102 to the outside of the image forming screen 102. It is possible to suppress the charge of the image forming screen 102. Specifically, the static electricity generated on the image forming screen 102 flows to the frame 101 via the supporting screen 103, so that the charging of the image forming screen 102 can be suppressed.

Here, the frame 101 into which static electricity from the image forming screen 102 flows may be grounded. If the surface resistivity Rо is too high, in other words, if the surface resistivity Rо is ^{higher than 1 × 10 11} [Ω / □], the support screen 103 transfers the static electricity generated on the image forming screen 102 to the frame 101. It becomes difficult to escape, and the image forming screen 102 remains charged.

Here, the surface resistivity Rо of the support screen 103 ^{is preferably 1 × 10 2} [Ω / □] or more, more preferably 1 × 10 ⁶ [Ω / □] or more, and 1 × 10 ⁸ [Ω / □] or more is more preferable. If the surface resistivity Rо of the supporting screen 103 is too low, in other words, if the surface resistivity Rо is ^{less than 1 × 10 2} [Ω / □], both the image forming screen 102 and the supporting screen 103 are charged. It becomes easy to do so, and it becomes difficult to suppress the charge of the image forming screen 102. The surface resistivityes Rо and Ri can be measured according to the provisions of JIS K6911 or JIS K7194.

The surface resistivity Ri of the image forming screen 102 and the surface resistivity Rо of the supporting screen 103 preferably satisfy the conditions shown in the following formula (1), and satisfy the conditions shown in the following formula (2). More preferred.
1 × 10 ⁷ ≦ Ri × Rо ≦ 1 × 10 ¹¹・ ・ ・ (1)
1 × 10 ⁸ ≦ Ri × Rо ≦ 1 × 10 ¹¹ ... (2)

When the surface resistivity Rо is 1 × 10 ² to 1 × 10 ^{11 [Ω / □], the surface resistivity Ri is 1 × 10 -4} to 1 × in order to satisfy the condition shown in the above equation (1). It may be 10 ⁹ [Ω / □]. Further, when the surface resistivity Rо is 1 × 10 ² to 1 × 10 ¹¹ [Ω / □], the surface resistivity Ri is 1 × 10 ^-4 to in order to satisfy the condition shown in the above equation (2). It may be 1 × 10 ⁹ [Ω / □]. The surface resistivity Ri is preferably at 1 × ¹⁰ 0 (= 1) or less.

By satisfying the condition represented by the above formula (1), the static electricity generated in the image forming screen 102 can be easily released to the outside of the image forming screen 102, and the charging of the image forming screen 102 can be suppressed. it can. Specifically, the static electricity generated on the image forming screen 102 flows to the frame 101 via the supporting screen 103, so that the charging of the image forming screen 102 can be suppressed.

On the other hand, it is preferable that the surface resistivity Ri of the image forming screen 102 and the surface resistivity Rо of the supporting screen 103 satisfy the conditions shown in the following formula (3).
1 × 10 ^-7 ≤ Rо / Ri ≤ 1 × 10 ¹⁵ ... (3)
The ratio (Rо / Ri) of the surface resistivity Rо and Ri represented by the above formula (3) is a value larger than 0.

By satisfying the condition represented by the above formula (3), the static electricity generated in the image forming screen 102 can be easily released to the outside of the image forming screen 102, and the charging of the image forming screen 102 can be suppressed. it can. Specifically, the static electricity generated on the image forming screen 102 flows to the frame 101 via the supporting screen 103, so that the charging of the image forming screen 102 can be suppressed.

The supporting screen 103 may support the image forming screen 102 and expand and contract during screen printing, and may have the above-mentioned surface resistivity Rо, and the specific structure of the supporting screen 103 may be appropriately determined. it can. For example, a coating layer having a surface resistivity Rо showing the above-mentioned value can be formed on the surface of the structure of the support screen 103. The coating layer can be formed by applying a solution containing a conductive material to the surface of the structure of the supporting screen 103. As the conductive material, for example, metal fine particles or carbon nanotubes can be used. The solution can include a resin and a surfactant to facilitate dispersion of the conductive material.

Further, the support screen 103 may be made of a woven fabric, or may be made of a composite in which the woven fabric and the sheet are integrally formed. In this complex, the woven fabric and the sheet can be laminated, or the woven fabric and the sheet can be connected to each other in a plane-arranged state. Further, in the composite, a plurality of woven fabrics or a plurality of sheets can be used.

Here, as the yarn constituting the woven fabric, for example, resin fibers or inorganic fibers can be used. By using such fibers, it is possible to allow the support screen 103 to expand and contract in screen printing so that the image forming screen 102 can be aligned with the printing surface.

Examples of the resin fiber include polyethylene terephthalate (PET), polypropylene, 6-nylon, 6,6-nylon, polyethylene, ethylene-vinyl acetate copolymer, polycarbonate, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), and the like. Polyether ether ketone (PEEK), modified polyphenylene ether (PPE), aramid, polyarylate, ultra high molecular weight polyethylene (UHMW), polyparaphenylene benzobisoxazole (PBO), polyparaphenylene benzobisthiazole (PBT), polybenzo Fibers formed of resins such as imidazole (PBI) and liquid crystal polymers can be used. As the inorganic fiber, for example, carbon fiber or glass fiber can be used.

The structure of the woven fabric is not particularly limited, and plain weave, twill weave, satin weave, weave weave and the like can be used. The woven fabric constituting the support screen 103 is not limited to one woven fabric, and a plurality of woven fabrics having the same woven structure and a plurality of woven fabrics having different woven structures can be used in layers. Further, the yarn constituting the woven fabric may be a monofilament or a multifilament having a core-sheath structure.

Examples of the material of the sheet constituting the supporting screen 103 include polyethylene terephthalate (PET), polypropylene, 6-nylon, 6,6-nylon, polyethylene, ethylene-vinyl acetate copolymer, polycarbonate, and polyphenylene sulfide (PPS). , Polyethylene terephthalate (PEN), polyetheretherketone (PEEK), modified polyphenylene ether (PPE) can be used.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Example 1)
An aluminum frame was used as the frame 101. The external dimensions of the frame 101 are 380 mm × 380 mm, the internal dimensions are 320 mm × 320 mm, and the thickness (the length in the direction orthogonal to the paper surface of FIG. 1) is 30 mm. Further, the frame 101 has a hollow structure formed of an aluminum plate having a wall thickness of 2 mm. The frame 101 is grounded.

The external dimensions of the image forming screen 102 are 220 mm × 220 mm. The image forming screen 102 is a stainless steel screen mesh (M10 325-023) woven from a stainless steel wire having a wire diameter of 23 μm and having a mesh number (number of threads per inch) of 325 (threads / inch). , NBC Metal Mesh Co., Ltd.) was used.

As the supporting screen 103, a mesh woven fabric woven from synthetic fiber polyethylene terephthalate (PET) having a diameter of 35 μm and having a mesh number of 280 (books / inch) is used, and the polyethylene terephthalate (PET) thread is used. A resin solution mixed with conductive fine particles (metal fine particles) was applied to the surface. The resin solution containing the conductive fine particles can be fixed to the surface of the polyethylene terephthalate (PET) thread by spraying it onto the surface of the polyethylene terephthalate (PET) thread and drying it.

The support screen so that the warp threads of the support screen 103 and the warp threads of the image forming screen 102 are lined up in the same direction, and the weft threads of the support screen 103 and the weft threads of the image forming screen 102 are lined up in the same direction. The 103 was fixed to the image forming screen 102. Further, the support screen 103 was fixed to the frame 101 so that the warp or weft of the support screen 103 was inclined by 23 ° with respect to the frame 101. As a result, the warp or weft of the image forming screen 102 is also tilted by 23 ° with respect to the frame 101.

After producing the combination screen plate 100 as described above, the photosensitive emulsion was applied to the image forming screen 102 to a thickness of 10 μm to form a printing pattern of 140 mm × 140 mm. When the tension at the center of the image forming screen 102 was measured using a tension gauge STG-75B (manufactured by Sun Giken Co., Ltd.), the tension was 1.0 mm and the clearance was 3.2 mm.

(Comparative Example 1)
EX280-35μ (manufactured by NBC Meshtec Inc.) was used as the supporting screen 103. EX280-35μ is a mesh woven fabric made of polyethylene terephthalate (PET) yarn. The surface of the polyethylene terephthalate (PET) thread is exposed to the outside, and the surface of the polyethylene terephthalate (PET) thread is not subjected to the surface treatment as in Example 1. The configuration other than the support screen 103 is the same as that of the first embodiment. When the tension at the center of the image forming screen 102 was measured using a tension gauge STG-75B (manufactured by Sun Giken Co., Ltd.), the tension was 1.0 mm and the clearance was 3.4 mm.

(Example 2)
In this embodiment, the mesh woven fabric described below was used as the supporting screen 103. The configuration other than the support screen 103 is the same as that of the first embodiment.

First, a carbon nanotube dispersion liquid in which a polyester resin, an acrylic resin, a nonionic surfactant (manufactured by Ebonic: WET 510), and a single-walled carbon nanotube (length: 1 μm or more and 20 μm or less) is dispersed in water is mixed with water. A coating solution was prepared by mixing with. On the other hand, a mesh woven fabric having a diameter of 35 μm and having a mesh number of 280 (threads / inch) was prepared by weaving yarns (warp yarns and weft yarns) formed of polyethylene terephthalate (PET) into a plain weave.

After the above-mentioned mesh woven fabric was subjected to corona treatment, the mesh woven fabric was immersed in the above-mentioned coating liquid, and the coating liquid was applied to the mesh woven fabric. The coating liquid applied to the mesh woven fabric was dried by hot air, and a coating layer composed of this coating liquid was formed on the surface of the mesh woven fabric. The mesh woven fabric on which this coating layer was formed was used as the supporting screen 103 of this example.

The composition of the coating liquid and the thickness of the coating layer described above are shown in Table 1 below. The thickness of the coating layer shown in Table 1 below is obtained by measuring the thickness of the coating layer with a scanning electron microscope (SEM) in three (optional) cross sections of the support screen 103 and measuring the thickness of the coating layer. It is the value obtained by adding and averaging.

The surface resistivity and the friction band voltage were measured for each of the combination screen plates 100 of Examples 1 and 2 and Comparative Example 1. Regarding the measurement of the friction band voltage, the surface of the image forming screen 102 is rubbed only 30 times with a waste cloth, and the friction band voltage immediately after this friction (0 minutes) and when 5 minutes have passed since the friction was completed. The friction band voltage and was measured. The friction band voltage was measured using an electrostatic measuring device (YC-102, manufactured by AS ONE).

In addition, the surface resistivity is measured by a resistivity meter in the high resistivity region (High Restor-UX MCP-HT800, constant voltage application / leakage current measurement method, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and a resistivity meter in the low resistivity region. Using (Lorester-GX MCP-T700, constant current application method / four-depth needle method, manufactured by Mitsubishi Chemical Analytech Co., Ltd.), the probe is brought into contact with the image forming screen 102 and the supporting screen 103 so as to straddle the surface resistance. The rate was measured. The measurement results are shown in Table 2 below.

In Examples 1 and 2, the friction band voltage immediately after friction (0 minutes) was lower than that in Comparative Example 1. Further, in Comparative Example 1, the friction band voltage was difficult to decrease even after 5 minutes had passed since the end of friction, but in Examples 1 and 2, when 5 minutes had passed after the end of friction. , The friction band voltage became 0 [kV]. Therefore, according to Examples 1 and 2, it can be seen that the static electricity generated on the image forming screen 102 can be efficiently removed.

100: Combination screen version, 101: Frame, 102: Image forming screen,
103: Support screen

Claims (4)

An image-forming screen for holding ink and forming an image,
It has the image-forming screen and a supporting screen that supports the image-forming screen by being fixed to the frame.
A combination screen version characterized in that the surface resistivity of the support screen is 1 × 10 ¹¹ [Ω / □] or less. The combination screen version according to claim 1, wherein the surface resistivity of the support screen is 1 × 10 ² [Ω / □] or more and 1 × 10 ^{11 [Ω / □] or less.} The combination screen version according to claim 1 or 2, wherein the image forming screen is made of metal. The condition shown in the following formula (I) is satisfied.
1 × 10 ⁷ ≦ Ri × Rо ≦ 1 × 10 ¹¹ ... (I)
Here, Ri is the surface resistivity [Ω / □] of the image forming screen, and Rо is the surface resistivity [Ω / □] of the supporting screen.
The combination screen version according to any one of claims 1 to 3, wherein the combination screen version is characterized in that.

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