JPH04307294A - Manufacture of screen gauze - Google Patents

Abstract

PURPOSE:To provide a device to manufacture polyester screen gauze which adheres to masking resin adequately. CONSTITUTION:A mesh fabric used is made of a core sheath type composite monofilament consisting of a core component which is of polyester and a sheath component which is of modified polyester containing 4 to 15wt.% of the third comonent of diol added to polyester. This mesh fabric is irradiated with ultraviolet ray comprising a 320nm or lower wavelength component at least, at 0.5Joule/cm<2> and then masking resin is applied to the fabric. This screen gauze is ideally compatible with the masking resin from a viewpoint of adhesive properties and is highly resistant against printing wear. Further, the screen gauze has an excellent printing resolution, and can be manufactured at low cost.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyester screen gauze which produces less scum during weaving and which has excellent adhesion to masking resins.

0002

[Prior Art] Mesh fabrics made of silk or stainless steel have been widely used as screen gauze for printing, but silk has problems with strength and dimensional stability, and stainless steel is prone to creep and elastic recovery. Currently, mesh fabrics made of polyester or nylon are often used because they have problems in terms of strength and durability, and are also expensive. In particular, polyester mesh fabrics are widely used because they have excellent dimensional stability and are suitable for printing printed circuit boards that require a high degree of precision. However, polyester has the drawback of insufficient adhesion to masking resins such as photosensitive emulsions for forming patterns on screens, and poor durability during repeated use.

[0003] As a method for solving such drawbacks, for example, Japanese Patent Laid-Open No. 62-220392 and Japanese Patent Laid-Open No. 63-17
No. 0034 and other publications propose a method of treating polyester screen gauze with low-temperature plasma.

[0004] The above-mentioned low-temperature plasma processing method requires a special vacuum container and a discharge device, and thus requires a large amount of equipment investment, and a significant increase in processing costs is unavoidable. Further, plasma treatment is generally performed while running a screen gauze in a vacuum container. It is difficult to introduce control means to prevent skewing in a vacuum chamber, and screen gauze fabrics generally have high elastic modulus and other essential factors that cause skewing and wrinkles. It's easy to do. In order to remove the wrinkles that have occurred, it is necessary to set the fabric under tension using a tenter or the like, but this process has disadvantages such as the gauze tearing. Furthermore, in plasma treatment, a slight decrease in fiber strength is unavoidable, and the fibers are likely to break due to the impactful tension applied to the gauze frame by, for example, an automatic gauze-stretching machine, which poses a problem.

[0005]

SUMMARY OF THE INVENTION The present invention improves the drawbacks of the prior art, improves the adhesion between a screen gauze made of polyester monofilament and a masking resin, and provides a highly durable screen gauze at a low cost. And quality
Both processes ensure stable manufacturing.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration. That is, the present invention provides a mesh fabric consisting of a core-sheath type composite monofilament in which the core component is polyester and the sheath component is polyester and a modified polyester containing 4 to 15% by weight of a third component consisting of polyalkylene glycol.
This method of producing screen gauze is characterized by irradiating the screen with ultraviolet rays containing wavelength components of m or less at a rate of at least 0.5 Joule/cm2, and then applying a masking resin. Furthermore, the present invention is characterized in that the screen gauze made of the core-sheath composite monofilament is fixed to a gauze frame and then irradiated with ultraviolet rays.

[0007] The chemical changes at the molecular level that make up polyester due to medium to far ultraviolet irradiation have not been completely elucidated, but it is thought that the generation of radicals, the increase in functional groups, the formation of crosslinks, etc. occur. . In particular, in the present invention, by using a core-sheath type composite monofilament in which copolymerized polyester is arranged in the sheath, it has become possible to further improve the effect of ultraviolet irradiation. In other words, modified polyester containing a third component has a looser amorphous structure than homopolyester (e.g. polyethylene terephthalate), has higher mobility of amorphous molecular chains, and is more likely to generate radicals and functional groups. . On the other hand, if the amount of ultraviolet rays is too high, the molecular structure will be destroyed, leading to a decrease in strength, but in the present invention, by localizing such components in the sheath, the monofilament as a whole can maintain the strength of

In the present invention, the ultraviolet rays to be irradiated are 32
It is important that short wavelength components of 0 nm or less are included. Ultraviolet rays of 320 nm or less have low transmittance and reflectance for polyester, and are strongly absorbed. For example, by using a low-pressure mercury lamp having a dominant wavelength of 254 nm, the adhesion to the masking resin can be significantly improved with a short treatment time even under normal pressure without necessarily requiring a vacuum. Furthermore, the polyester fiber obtained by the above-mentioned treatment method can selectively treat the surface layer of the fiber, so that the following effects can be achieved. a. Since the UV irradiation treatment mainly affects the fiber surface layer, the strength retention rate of the monofilament as a whole is high. b. Good adhesion can be obtained with low irradiation energy. Ultraviolet irradiation treatment can be performed at any stage from the weaving of the screen gauze to the finishing process, but by irradiating the screen gauze with ultraviolet light after fixing it to the gauze frame,
The operations up to the gauze-stretching process are completely the same as conventional ones, which is particularly preferable because there are no wrinkles or breakage problems during the process. Furthermore, since the position of the tissue point made up of the warp and weft threads of the screen gauze is fixed, the adhesive surface with the masking resin will not become an area that has not been irradiated with ultraviolet rays. This ensures uniform high adhesion down to the smallest detail. Furthermore, since the irradiated area has a higher yarn-to-yarn friction coefficient than the unirradiated area, misalignment during printing is reduced and printing accuracy is improved. Further, it is sufficient that the pattern portion within the gauze frame is substantially subjected to ultraviolet irradiation treatment, and there is an advantage that only the necessary portions can be efficiently treated.

The amount of ultraviolet irradiation is preferably 0.5 joules/cm2 or more and 20 joules/cm2 or less, more preferably 2 to 15 joules/cm2.
Good. If it exceeds 20 joules/cm2, the strength retention rate of the screen gauze starts to decrease, so it is better to avoid it.

[0010] As a device for irradiating ultraviolet rays, a known printing machine or the like can be used. As a light source for such a device, a high-pressure mercury lamp, a metal halide lamp, a low-pressure mercury lamp, etc. can be used, but especially a low-pressure mercury lamp,
It is preferably used because it has a dominant wavelength of 320 nm or less and has a long lamp life.

As for the irradiation method, one side of the screen gauze may be irradiated, but it is more preferable to irradiate both sides. Furthermore, in performing the irradiation treatment, it is preferable to effectively utilize the ultraviolet rays that have passed through the screen gauze opening by installing an ultraviolet reflection plate (for example, a white plate made of calcium sulfate or magnesium oxide) on the back side of the screen gauze.

Furthermore, when ultraviolet irradiation treatment is performed, the temperature of the screen gauze tends to rise due to heat radiation and heat rays from the irradiation device. It is preferable to maintain the surface temperature of the screen gauze at 40° C. or lower, since excessive temperature rise will cause changes in the gauze properties. Examples of methods for this purpose include using an irradiation device with a cooling device, using a lamp with low heat rays, using a heat ray cut filter, and cooling with cooling air, either alone or in combination. good. Furthermore, the screen gauze used may be undyed, or may be dyed to prevent halation.

The polyester of the core component in the present invention is a polyester mainly composed of polyethylene terephthalate, but may also be polyethylene-2,6 naphthalate, polybutylene terephthalate, or liquid crystalline polyester. The sheath component must be a modified polyester containing a terephthalic acid component and an ethylene glycol component as main components, and a third component of polyalkylene glycol such as polyethylene glycol, polypropylene glycol, or polytetramethylene glycol in an amount of 4 to 15% by weight. It is. The molecular weight of the polyalkylene glycol is preferably 600 or more, more preferably 8,000 or more in terms of scum during weaving. A smaller amount (usually 5
It may also be a copolymerized polyester blended with a dicarboxylic acid such as isophthalic acid or sebacic acid or a glycol such as diethylene glycol or butanediol.

[0014] If the blending ratio of the third component is 4% by weight or more, a sufficient effect will be observed. However, if it is added in an amount exceeding 15% by weight, dimensional stability and chemical resistance will decrease, which is not preferable for plate removal or reuse. A more preferable range of blending ratio is 6 to 10% by weight. The core-sheath composite form only needs to be that the polyester blended with the third component is substantially arranged on the fiber surface, and may be any of the concentric single-core type, eccentric single-core type, and multi-core type, but monofilament A concentric single core type is preferred from the viewpoint of preventing curling and improving workability in the weaving preparation process. The core:sheath composite ratio is 70:30 to 9 in terms of area ratio.
5:5 is good. If the composite ratio of the sheath components exceeds 30%, the strength of the monofilament will decrease significantly.

7 The preferred range is core:sheath 80:20-9
It is 0:10. In the present invention, since a modified polyester containing polyalkylene glycol is used for the sheath component, the structure of the sheath component becomes soft, and the generation of scum caused by scraping of the fibers due to friction with reed feathers etc. during screen gauze weaving is also suppressed. be able to.

[0016] In addition, for the purpose of preventing halation and improving weavability, polymers containing fine particles of titanium dioxide, silicon dioxide, alumina, etc., or particles generated in the polymer during the polymer manufacturing process, that is, polymers containing internal particles, are used. It may be.

When the polyester of the core component is polyethylene terephthalate, the intrinsic viscosity measured in an 0-chlorophenol solution at 35° C. is suitably 0.5 or more, preferably 0.7 to 1.4. Furthermore, a polymer containing an ultraviolet absorber may be used to prevent halation during exposure to ultraviolet light in the screen plate-making process.

When producing a screen plate by a direct method using the screen gauze of the present invention, any commercially available photosensitive emulsion, heat-sensitive emulsion, etc. can be used as the masking resin. Furthermore, since the affinity with these emulsions is improved, coating properties are good and the film thickness is uniform, and furthermore, the adhesive strength with the emulsion resin is high and printing resistance is excellent.

In addition, in indirect method and direct method plate making, since the screen gauze is hydrophilic, it is easy to obtain a uniform water film, and image patterns or photosensitive films can be easily obtained from indirect method film or direct method film. When transferring the image to the screen gauze, the transfer can be ensured.

As described above, the method of the present invention has the effect of improving the adhesion between the screen gauze and the masking resin,
It is particularly suitable for high-precision printing of IC printed circuits, etc.

[0021]

[Examples] The present invention will be explained in detail with reference to Examples below. In addition, each physical property value in an Example was calculated|required by the following method.

A. Test method Sumitomo 3M #8 on each screen gauze pattern
After applying 10 (Scotch mending tape),
This operation of peeling off the tape is repeated 5 times on the same surface, and the total number of grids attached to the tape is recorded. Therefore, the smaller the total number of grids attached to the tape, the higher the adhesive strength between the screen gauze and the masking resin.

Example 1 Polyethylene terephthalate with an intrinsic viscosity [η]=0.80 was used as the core component of a composite monofilament, and polyethylene glycol (molecular weight 1000) and polytetramethylene glycol (molecular weight 1000) were each used as the core component during polyethylene terephthalate polymerization. A concentric circular composite monofilament was spun at a spinning temperature of 300° C. and a spinning speed of 900 m/min using modified polyethylene terephthalate obtained by blending the amounts shown in Table 1 as the three components as a sheath component. The composite ratio of the core and sheath at this time was 80:20 in terms of area ratio. The obtained undrawn yarn monofilament was heated at 95°C and 14°C.
Using a pair of hot rolls heated to 0°C, 4.4
The yarn was drawn twice to obtain a drawn yarn having a fineness of 7 denier, a breaking strength of about 7 g/d, a breaking elongation of about 20%, and a 10% modulus of about 6 g/d.

[0024]

[Table 1]

The monofilament was woven by a conventional method and finished to obtain a 420 mesh high mesh gauze. Table 1 shows the scum generation during weaving and the heat setting property (gauge tearing) during finishing.

Monofilament of the present invention (Experiment No. 1
, 2, 4), there is almost no occurrence of scum, especially lint-like scraping during weaving, and there is no tearing of the gauze even when it is stretched by a few percent while being heated in the warp and weft directions with a tenter during finishing processing. It had excellent heat setting properties.

On the other hand, Experiment No. 1 in which 18% by weight of polyethylene glycol was added to the sheath component. In No. 3, the gauze was likely to tear due to weft breakage during heat setting, and the gauze was also likely to tear due to the dynamic tension when the gauze was stretched onto the gauze frame. In addition, experiment No. 1 of polyethylene terephthalate single yarn. Regarding No. 5, there was a lot of scum, and it was necessary to wash the reed feathers frequently.

Next, experiment No. Using the conventional method, apply the screen gauze from No. 1 to an aluminum gauze frame at a tension of 45 N/cm.
It was covered with gauze and subjected to ultraviolet irradiation treatment using a 4 mw/cm2 low pressure mercury lamp. The distance from the low-pressure mercury lamp to the screen gauze was 20 cm. Table 2 shows each cumulative light amount.
It was shown to. The illumination meter is UV-2 manufactured by Oak Seisakusho Co., Ltd.
5 was used. Next, a direct photosensitive emulsion Plus Print 399R-7 (manufactured by Gooh Kagaku Kogyo Co., Ltd.) was applied, dried, and layered to give a film thickness of 10 μm. After forming the photosensitive coating, each screen gauze has a grid pattern of 50 rows and 20 columns.
000 pieces, and the base size unit is each 0.1mm x 0.000 pieces.
1mm (No. 1), 0.2mm x 0.2mm (No.
2) and 0.3 mm x 0.3 mm (No. 3). The printing was carried out using a 4 kW high pressure mercury lamp and exposure for 3 minutes at a distance of 1.5 m. Then, after immersing in water for 5 minutes, unexposed areas were removed by water spray.

A tape peeling test was carried out on the screen gauze on which the checkerboard pattern had been printed in this manner, and the adhesive strength of the photosensitive coating was measured. The results are shown in Table 2.

[0030]

[Table 2]

As is clear from Table 2, all of the screen gauze obtained by the method of the present invention have excellent adhesion to masking resins made of photosensitive emulsions.

[0032]

[Effects of the Invention] The screen gauze obtained by the method of the present invention has excellent adhesion to the masking resin, does not fall off due to peeling of the masking resin during printing, has improved printing resistance, and has excellent adhesiveness to the masking resin. Even if the adhesion area between the fibers and the masking resin is small, there is little chance of them falling off. Furthermore, since ink permeability is improved, it is suitable for printing electronic components such as IC printed wiring that require high resolution.

Claims (2)

[Claims] Claim 1: A mesh fabric consisting of a core-sheath type composite monofilament in which the core component is polyester and the sheath component is polyester and a modified polyester containing 4 to 15% by weight of a third component consisting of polyalkylene glycol.
At least 0.5% of ultraviolet rays containing wavelength components of 0nm or less
A method for producing screen gauze, which comprises irradiating with joules/cm2 and then applying a masking resin. 2. The method of manufacturing screen gauze according to claim 1, wherein the mesh fabric is fixed to the gauze frame and then irradiated with ultraviolet rays.