JPS62109056A - Screen for printing - Google Patents

Abstract

PURPOSE:To increase the adhesive power between a photosensitive resin and fiber fabric and to improve the durability for the repetitive printing by forming a layer reformed by a low-temp. plasma treatment on the surface on the photosensitive resin adhered side of a monofilament fabric. CONSTITUTION:This screen is constituted of a screen base fabric consisting of the monofilament fabric and photosensitive resin layer exposed, developed and fixed according to a desired pattern on said base fabric. The layer reformed by the low-temp. plasma treatment is formed on the surface on the photosensitive resin adhered side of the monofilament fabric. The diameter of the monofilament fibers is preferably 25-150mum. The useful photosensitive resin is exemplified by a water soluble polymer as well as a hydroxyl group-contg. polymer, photoplymn. type photopolymer having a photoplymn. type photosensitive group. The low-temp. plasma treatment is executed for the prescribed time, for example, several seconds - several minutes in the presence of gas having etchability, gas having no etchability or gaseous mixture composed of the gas having the etchability and the gas having no etchability 0.01-10Torr pressure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a printing screen. More specifically, the present invention relates to a printing screen, and more specifically, a screen base fabric made of monofilament fabric, and a screen formed with a desired pattern thereon. The present invention relates to an improved printing screen comprising a resin layer and having high durability against repeated printing.

[Conventional technology]

Conventionally, in order to produce a printing screen, first a photosensitive resin solution is applied or a photosensitive resin film is adhered to one or both sides of a screen base fabric made of synthetic fiber, particularly monofilament fabric such as polyester, to form a desired pattern. Visible light and/or ultraviolet light is irradiated through the document.

At this time, only the portion of the resin layer that receives the light undergoes a photocrosslinking reaction or a photodecomposition reaction. Thereafter, the soluble portion of the resin layer is washed away with water, chemicals, etc. to obtain a printing screen having a desired pattern. At this time, if the adhesive strength between the photosensitive resin and the filament fiber cloth is weak, the resin will peel off due to repeated printing, making it impossible to repeatedly print a precise pattern. In order to solve these problems, especially for polyester monofilament base fabrics, this screen base fabric is treated with Ml using an alkaline aqueous solution, thereby increasing the adhesion of the screen base fabric to the photosensitive resin.
A method has been adopted to improve the durability of repeated printing. However, in order to obtain adhesive strength that shows satisfactory durability with this method, it is necessary to perform excessive alkali acid reduction treatment, which leads to an extreme decrease in strength, especially for filament yarns with small fiber diameters. Problems such as the screen base fabric breaking during repeated printing have occurred.

[Problem that the invention seeks to solve]

In a printing screen in which a monofilament base fabric is coated with a photosensitive resin, (1) the adhesion between the monofilament base fabric and the photosensitive resin is strong, and (2) the strength reduction of the monofilament base fabric is minimized. [Means and effects for solving the problem] The printing screen of the present invention has a screen base fabric made of monofilament fabric, and a desired pattern is exposed, developed, and fixed on the base fabric. The fabric is characterized in that a modified layer is formed by low-temperature plasma treatment on the photosensitive resin adhesive side surface of the monofilament fabric.

The presence of the low-temperature plasma modified layer strengthens the adhesion between the monofilament base fabric and the photosensitive resin layer, so that the resulting printing screen can exhibit excellent repeated printing durability.

Monofilament fabrics useful in constructing the screen base fabric used in the present invention include natural fibers such as silk,
Inorganic fibers, such as glass fibers, carbon fibers, metal fibers, recycled fibers, such as viscose rayon, cupro, etc., semi-synthetic fibers, such as g- and tri-acetate fibers, and synthetic fibers, such as nylon 6, nylon. 66, polyester (polyethylene terephthalate etc.) fibers, aromatic polyamide fibers, acrylic fibers, polyvinyl chloride fibers, polyolefin fibers and water insolubilized or t
It is made of at least one type of monofilament fiber selected from mono-solubilized polyvinyl alcohol fibers. Monofilament fiber diameter is 25-150μm
It is preferable that

If the diameter is smaller than 25 μm, the monofilament may have insufficient tensile strength and may be difficult to cut, making weaving difficult. Further, if the diameter is larger than 150 μm, a good printing result with high precision may not be obtained.

Photosensitive resins useful in the present invention include water-soluble polymers,
For example, esterified products of polyvinyl alcohol with a molecular weight of about 1300 to 1500 and a compound having a photosensitive group, such as cinnamic ester of the above-mentioned polyvinyl alcohol, β-furyl acrylic ester, α-cyano cinnamic ester, p-acid cinnamic ester, etc. ester, β-
Styryl acrylic ester, α-cyano-β-styryl acrylic ester, p-phenylene diacrylic ester, p-(2-benzoylvinyl)-cinnamic ester, diphenylcyclopropene ester, etc.
Photodimerizable photopolymers such as stilbene compounds and α-phenylmaleimide compounds, and hydroxyl group-containing polymers,
For example, a resin material that is a mixture of polyvinyl alcohol and a photolytic photopolymer such as a diazo compound or an azide compound, as well as acrylic ester, methacrylic ester, crotonic ester groups, etc. in the polymer molecular chain or side chain.
Photopolymerizable photopolymers containing photopolymerizable photosensitive groups such as maleic acid ester groups, fumaric acid ester groups, itaconic acid ester groups, vinyl ester groups, vinyl ester groups, vinyl ether groups, vinylbenzene groups, allyl ether groups, acrylamide groups, etc. For example,

Further, the photosensitive resin may contain a sensitizer, such as 5-nitroacenaphthene, N
-Acetyl-4-nitro-1-naphthylamine, 2-ethylanthraquinone, ■.

2-Benzanthraquinone, benzophenone, acetophenone, azobisisobutyronitrile, etc. can be used. The photosensitive resin is applied in the form of a solution or film onto the screen base fabric and dried or adhered. Any of the direct method, direct method, and indirect method may be used to create the screen version.

At least one surface of the screen base fabric is subjected to low temperature plasma treatment.

Low temperature plasma treatment is 0. For a predetermined period of time, e.g., several seconds, in the presence of an etching gas, a non-etching gas, or a mixture of an etching gas and a non-etching gas under a pressure of O1 to l O Torr. It will last for a few minutes. If the treatment time is too short, the effect of improving adhesion will be insufficient, and if the treatment time is too long, the mechanical strength of the screen base fabric may decrease excessively. For the low-temperature plasma treatment, for example, low frequency waves or microwaves can be used as the discharge frequency band, and direct current can also be used. As for the plasma generation mode, any of glow discharge, corona discharge, spark discharge, silent discharge, etc. may be used.

A gas containing oxygen and/or argon is used as the etching gas. By low-temperature plasma treatment using a chemical gas, oxygen-containing functional groups are formed on the surface of the monofilament fiber cloth, and a modified layer with fine irregularities is formed. Care must be taken because excessive plasma treatment in the presence of an etching gas will increase irregularities on the surface of the monofilament, causing defects such as poor ink separation during printing.

As the gas having no etching properties, a gas containing at least one selected from nitrogen, hydrogen, and carbon oxide is used. A modified layer having functional groups containing oxygen and nitrogen is formed on the surface of the monofilament by low-temperature plasma treatment using a gas that does not have etching properties. In this case, the monofilament surface has no irregularities and has a relatively smooth surface.

By low-temperature plasma treatment using a mixed gas of a gas that does not have etching properties and a gas that has etching properties, it is possible to obtain a modified layer in which desired functional groups are formed without excessive formation of irregularities on the monofilament surface. . A photosensitive resin is applied or adhered to the modified surface of a monofilament base fabric on which a modified layer has been formed by low-temperature plasma, and visible light and/or ultraviolet rays are irradiated through a document having a desired pattern. Thereafter, this is subjected to necessary development treatment to obtain the printing screen of the present invention.

The photosensitive resin layer can be formed on one side or both sides of the base fabric, and when the photosensitive resin layer is formed on only one side of the base fabric, the opposite side of the fabric may also be subjected to low-temperature plasma treatment. In this case, the photosensitive resin wraps around and adheres to the opposite surface of the monofilament, which may have the effect of improving the adhesive durability between the base fabric and the photosensitive resin layer.

[Execution It]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A polyester monofilament cloth with the following structure was set at a predetermined position in a low-temperature plasma processing apparatus, and the inside of the apparatus was heated to 1.
After exhausting the air to a pressure of 0-'Torr, oxygen gas was introduced through the gas introduction pipe to reduce the pressure inside the device to 0.2 Torr.
It was maintained at Torr. Thereafter, processing was performed using a high frequency type -tA (double frequency 13.56 MHz manufactured by Nippon Koshupa) at an output of 500 watts for a processing time of 30 seconds to 3 minutes.

Table 1 shows the tensile strength of the polyester monofilament fabric forming the modified layer.

Next, after thoroughly wetting the modified polyester monofilament fabric with water, a photosensitive resin 74 BvL was applied to the surface of the modified polyester monofilament fabric.
(ALITOTYP [made by i company, CAPILL [X 3
5) was attached, lightly compressed with a squeezing roll, and then dried at a temperature of 40° C. for 30 minutes. The adhesive strength between the photosensitive resin film and the monofilament fabric in the obtained laminate was measured, and the results are also shown in Table 1.

As a comparative example, a polyester monofilament fabric made of the same fiber as above was impregnated with an aqueous solution of caustic soda, and then subjected to alkali weight loss using a pad steam method, and the weight loss rate was adjusted between 3% and 40%. The tensile strength of the screen base fabric and the adhesive strength between the screen base fabric and the photosensitive resin film were measured, and the results are shown in Table 2.

Table 1 In addition, the laminate after the photosensitive resin film was attached was irradiated with ultraviolet rays for 3 minutes using a high-pressure mercury lamp of KH, and the adhesive strength between the photosensitive resin layer obtained by development and the fabric was measured. The results were also good, showing almost the same trends as in Tables 1 and 2.

Table 2 Example 2 A polyester monofilament fabric having the same structure as in Example 1 was treated with low-temperature plasma in the same manner as in Example 1. did. However, here, a mixed gas of nitrogen and hydrogen (mixing ratio 1:2) is used as the introduced gas, and the pressure inside the device is set to 0.5 Torr.
r for 3 minutes at an output of 100 watts. Table 3 shows the adhesive strength of this screen base fabric to the photosensitive resin film (after which the same operation as in Example 1 was repeated) and the change in adhesive strength over time. The tensile strength of the modified screen base fabric was equivalent to that of the non-low temperature plasma treated product.

Further, when the adhesive strength between the photosensitive resin obtained by irradiating and developing with ultraviolet rays and the base fabric was measured in the same manner as in Example 1, the results were almost the same as the values shown in Table 3.

Example 3 The same m-weave polyester monofilament fabric as in Example 1 was treated with low-temperature plasma in the same manner as in Example 1. However, here, a mixed gas of argon, nitrogen, and hydrogen (
Using a mixing ratio of 2:l:l), the pressure inside the device is Q,
1 Torr and an output of 500 W for 30 seconds. Next, this modified polyester monofilament fabric was fixed under tension to an aluminum frame of 50 cm x 50 cm and sufficiently soaked with water.
Ultraviolet rays were irradiated for 3 minutes using a high-pressure mercury lamp with a decuff KW. This was subjected to a prescribed development treatment with water to obtain a printing screen plate. Table 4 shows the results of the adhesiveness (cellotape peel test) of this product.

Notes in Table 4 in the margin below: * (Judgment criteria) ○Near 1 does not separate △: Partially peels off ×: Fully peels off [Effects of the invention] The printing screen cloth obtained by the present invention has tensile strength of the fibers. The adhesive strength between the photosensitive resin and the fiber cloth is strengthened without compromising physical properties such as
It has excellent durability against repeated printing.

In addition, since the adhesive strength between the fiber and the photosensitive resin is strong,
Even if the adhesive area is small, it is possible to obtain adhesive strength sufficient for practical use. This makes it possible to obtain a printing screen with a pattern having a small line width.

Claims (1)

[Claims] 1. A screen base fabric made of monofilament fabric;
The desired pattern is then exposed, developed and
1. A printing screen comprising a fixed photosensitive resin layer, and a modified layer formed by low-temperature plasma treatment on the photosensitive resin adhesive side surface of the monofilament fabric. 2. The low temperature plasma modified layer has a temperature of 0.01 to 10 Tor
The printing screen according to claim 1, which is formed by low-temperature plasma treatment in the presence of an etching gas under a pressure of r. 3. The etching gas is oxygen and/or
The printing screen according to claim 2, which contains argon or argon. 4. The low temperature plasma modified layer has a temperature of 0.01 to 10 Torr.
formed by low-temperature plasma treatment in the presence of a non-etching gas under a pressure of r.
A printing screen according to claim 1. 5. The printing screen according to claim 4, wherein the non-etching gas comprises at least one selected from hydrogen, nitrogen, and carbon monoxide. 6. The low temperature plasma modified layer has a temperature of 0.01 to 10 Torr.
Claims 1. The printing screen according to item 1. 7. The printing screen according to any one of claims 1 to 7, wherein the tensile strength of the screen base fabric modified by low-temperature plasma is 95% or more of the tensile strength of the screen before modification. . 8. The printing screen of claim 1, wherein the monofilament fabric is selected from natural monofilaments, inorganic monofilaments, regenerated cellulose monofilaments, semi-synthetic monofilaments, and synthetic monofilaments. 9. The printing screen according to claim 1, wherein the monofilaments in the monofilament fabric have a diameter of 25 to 150 μm. 10. The printing screen according to claim 1, wherein the photosensitive resin layer is formed on only one side of the base fabric. 11. The printing screen according to claim 1, wherein the photosensitive resin layer is formed on both sides of the base fabric.