JPH0725231B2 - Print screen - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a printing screen made of a polyester mesh, and an object of the present invention is to prevent a decrease in the strength of the mesh and to form a photosensitive resin layer. It is to provide a mesh with improved adhesion.

(Prior Art) A polyester mesh used for screen printing generally has poor adhesion to a photosensitive resin layer, and has problems in printing accuracy, reproducibility and printing durability. Therefore, attempts have been made to improve the adhesiveness of the mesh by various chemical treatments, flame treatments, etc., but rather the strength of the mesh decreases, and there are problems such as the occurrence of phenomena such as breakage at the time of stretching and printing. However, we cannot yet find a fundamental solution.

(Structure of the Invention) As a result of intensive research to solve the above-mentioned conventional problems, the inventors of the present invention performed low-temperature plasma treatment in argon or helium gas at a gas pressure of 0.005 to 5 torr for 2 to 10 seconds. The present invention has been found to solve the above-mentioned problems by using a mesh composed of a polyester mesh of a mesh or more and having a surface wetted with a liquid having a surface tension of 40 dyne / cm or more as a printing screen.

Explaining this in detail below, in the production of the printing screen of the present invention, first, a filament having a wire diameter of 20 to 100 μm is woven into a predetermined thickness and 50 to 500 mesh by a conventional method, and then refined, heat set, etc. The polyester mesh finished by means is subjected to a low temperature plasma treatment in a non-oxidizing gas. In this case, the mesh is held in a plasma generator capable of reducing the pressure, and the pressure is reduced to 0.005 to 5 Torr by argon gas. Or, while helium gas is ventilated, a high frequency power of 10 KHz to 100 MHz is applied between the electrodes for 2 to 1
It is performed by applying for 0 seconds. As the discharge frequency band, low frequency, microwave, direct current, etc. can be used in addition to the above high frequency.

The low temperature plasma generator is preferably an internal electrode type,
Depending on the case, either an external electrode type or a coil type may be used.

However, in any of the above methods, it is necessary to prevent the surface to be treated from being deteriorated by the heat of discharge.

Although the method of the present invention is preferably carried out by the internal electrode method as described above, the shape of the electrode at this time is not particularly limited, and the input side electrode and the ground side electrode may have the same shape or different shapes. It may be any of various types such as a plate shape, a ring shape, a rod shape, and a cylinder shape, and may be a type in which the metal inner wall of the processing apparatus is grounded as one electrode. Although copper, iron, aluminum or the like is generally used as the input side electrode, in order to maintain stable discharge, it is preferable that the electrode is insulatingly coated with glass, enamel, ceramic or the like having a withstand voltage of 10,000 V or more. . In particular, the insulation-coated rod-shaped electrode is suitable for locally generating effective plasma.

Regarding the electric power applied between the electrodes, if it is too large, the object to be treated will be decomposed and deteriorated due to heat generation etc., and the strength of the mesh will be reduced. It is preferable to control to 150 kw / m ² or less.

The plasma treatment time is preferably 2 to 10 seconds. Gas pressure of the plasma generator is 0.005-5 torr, preferably 0.01
The range is ~ 1.0 torr. At a pressure of 0.005 Torr or less or 5 Torr or more, stable discharge is difficult to maintain, and the mechanical strength of the mesh is lowered or the surface is deteriorated by heat, which is not preferable.

The printing screen proposed by the present invention has a surface wettability of 40 dyne / cm or more of a surface tension subjected to low temperature plasma treatment,
Therefore, the adhesiveness between the mesh and the photosensitive resin layer is remarkably excellent in the coating or laminating of the photosensitive resin in the next step.

It is caused by a decrease in the elongation, elasticity, strength, etc. of the mesh itself, which has been a problem in surface treatment such as various chemical treatments, flame treatments, corona treatments, etc. that were conventionally performed to improve adhesion. Trouble such as tightness or mesh breakage during printing is sufficiently solved by the present invention.

The printing screen of the present invention is stretched on a predetermined screen frame, coated with a photosensitive resin by a direct method, a direct method, an indirect method, or the like, and then exposed by a method such as exposure. After being formed, it is used as a plate-making plate for screen printing.

The printing screen of the present invention can be plasma-treated in a short time, the strength of the mesh is maintained, the adhesiveness between the screen mesh and the photosensitive resin layer is significantly improved, and the printability and solvent resistance are improved. The excellent life of the printing plate is significantly improved. In addition, due to the excellent wettability imparted to the mesh, it has excellent printing characteristics with respect to ink permeability during printing, plate separation, etc., and can be used for pattern printing, character printing, name plate printing, color printing, etc. In the field of screen printing, it is possible to stably perform fine and clear printing.

The present invention will be described in the following examples.

Example 1 A mesh made of polyester with 300 meshes in a low temperature plasma generator (Nippon Special Woven Co., Ltd. Super Strong)
T300S), and then pressure was reduced to 0.005 torr. In this state, argon was ventilated and the pressure was adjusted and maintained at 0.5 torr, then the frequency was 110 KHz and the area of the positive electrode was 30 KW / m.
A power of ² was applied and plasma treatment was performed for about 10 seconds. When the surface tension of this mesh surface was measured, it was 48 dyne / cm.
Met.

Wettability test method: An ethylene glycol monoethyl ether / formamide solution (Wako Pure Chemical Industries, Ltd. wettability standard solution) set to a predetermined surface tension was applied to the mesh surface, and the surface tension of the solution when wetted was measured. The value was used as a standard for wettability (JIS K-6
According to 768).

The mesh thus obtained was stretched by a conventional method and a strength test was conducted (Table 1). However, the tension condition at this time is 56 cm
It was 1.00 mm with a tension gauge STG-75B (manufactured by Sun Giken Co., Ltd.) using a square frame.

Furthermore, in the same way, we stretched the mesh into square mesh with a square mesh of 150 mm.
I baked 0 pieces. The photosensitive resin used here is Encozol 2 (Nazda), coating thickness is 12 μm, exposure time is 4K.
W high-pressure mercury lamp (Oak Co., Ltd.) was used for about 3.5 minutes. A bagron tape Y683 manufactured by Sumitomo 3M Co., Ltd. was attached to the thus-obtained pattern, and it was strongly rubbed with a finger and then peeled off. The adhesiveness with was investigated (Table 2).

When the screen was printed on a flexible printed wiring board to examine the durability of the plate film and the strength of the plate, the mesh of the present invention was capable of printing 6000 sheets. On the other hand, the plate film of the untreated plasma was peeled off 2000
The number was limited.

Test method for strength of mesh upholstery: A bundle of 5 needles having a diameter of 0.56 mm was punched with a needle every 3.5 cm on the diagonal line of the mesh upholstery to check whether the mesh was torn.

Breaking tension test: The mesh was stretched in a biaxial direction by a conventional method until the mesh was broken, and the tension at break was measured with a tension meter. However, this value is a measurement of the depth of depression of a tension meter placed in the center of the mesh, and the smaller this value is, the stronger the tension is.

Comparative Example 1 Superstrong T300S was subjected to low temperature plasma treatment in the same manner as in Example 1 except that oxygen was used instead of argon. The surface tension of the mesh surface at this time is 50 dyne / cm.
Met.

A mesh strength test and an adhesion test were performed on the above meshes in the same manner as in Example 1 (Tables 3 and 4).

When printing was performed in the same manner as in Example 1, the mesh was broken after 1000 sheets and printing became impossible.

Comparative Example 2 A polyester mesh having a mesh number of 180 (T180S manufactured by Nippon Special Weaving Co., Ltd.) was subjected to the low temperature plasma treatment in the same manner as in Example 1. Oxygen was flowed at 5 Torr, and the treatment was performed under the conditions of an applied power of 120 KW / m ² and a plasma irradiation time of 20 seconds. The surface tension of the mesh at this time was 50 dyne / cm.

With respect to this mesh, the strength test and the adhesiveness of the mesh were examined in the same manner as in Example 1 (Table-5 and Table-6).

When printing was carried out in the same manner as in Example 1, the plate was broken after 500 sheets and printing became impossible.

Example 2 The same plasma treatment as in Example 1 was performed using a yellow-dyed polyester mesh having a mesh number of 250 (Super Strong T250T: manufactured by Nippon Special Woven Co., Ltd.). However, the plasma processing condition is 15K by flowing helium to 0.1 torr.
W / m ² was applied and the treatment was performed for 2 seconds of irradiation time. The surface tension of the mesh at this time was 44 dyne / cm.

The strength test and the adhesion of the mesh were examined in the same manner as in Example 1 (Table-7 and Table-8).

When printing was performed using the plate of the present invention as in Example 1, 10,000 prints were possible. The plate film of the untreated plasma product peeled off, and the limit was 3000 sheets.

Continuation of the front page (56) References JP 62-11691 (JP, A) JP 62-13342 (JP, A) JP 62-16145 (JP, A) JP 62-109056 (JP , A)

Claims (1)

[Claims] 1. A polyester mesh of 50 mesh or more subjected to low temperature plasma treatment in argon or helium gas having a gas pressure of 0.005 to 5 torr for 2 to 10 seconds, and the surface of the mesh is wet with a liquid having a surface tension of 40 dyne / cm or more. A printing screen characterized by being processed.