JP2939015B2 - Manufacturing method of screen gauze for printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a screen gauze for printing .
Construction method . More specifically, the present invention relates to a method for producing a screen gauze for printing, which has an increased opening area of the screen gauze and has good permeability of ink and the like.

[0002]

2. Description of the Related Art Polyester monofilaments as a material constituting a screen gauze for printing have a high elastic modulus and excellent dimensional stability, and thus have been frequently used for printing electronic circuits. In recent years, there has been an extremely strong demand for high-precision printing of electronic circuits. In order to realize such high-precision printing, generally, the weave density of the screen gauze is increased to create a fine line pattern. In such a method of simply increasing the weaving density, there is a problem in that the individual openings of the woven fabric, that is, the opening area is reduced, so that the ink passing property is reduced and the printing accuracy is rather reduced. In order to solve this problem, the denier of the monofilament is being studied, but the strength of the monofilament is reduced, and the warp and weft breaks frequently occur due to the tension and impact force when weaving screen gauze, making it difficult to weave. There was a problem of becoming. Therefore, when making the monofilament finer, it is necessary to simultaneously increase the strength. However, when the strength is increased by stretching at a high magnification in the production process of the raw yarn, the filament becomes a monofilament having a high degree of crystal orientation, and the surface of the monofilament is easily shaved by a feather of a weaving machine. This scum not only shortens the continuous weaving time, but also is woven into the screen gauze to cause printing defects, and is not suitable for high precision printing.

On the other hand, Japanese Utility Model Publication No. 41-20626 discloses a method of increasing the number of meshes of a screen gauze by heat shrinkage and then hydrolyzing the fiber surface with an alkaline solution to increase the opening area. .
However, in this method, it is essential to perform a heat shrink treatment prior to the weight reduction treatment, and this is an effective means for increasing the weaving density. On the other hand, as clearly shown in FIG. There is a fatal drawback that the fibers meander during the process and the mesh structure becomes uneven. Further, since the weight loss rate is easily influenced by the concentration, temperature and treatment time of the alkaline solvent, it is difficult to keep the weight loss rate constant and there is a problem that reproducibility is poor. In addition, since the strength of the screen gauze is greatly reduced by the weight loss treatment, it is not possible to stretch the high tension gauze, and since the fiber structure becomes loose, the stress relaxation of the screen plate becomes large and the dimensional accuracy is inferior. It was not suitable for high precision printing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the drawbacks of the prior art and to provide a high-measurement screen gauze for high-precision printing which has a high mesh, a large opening area, and excellent ink permeability. I do.

[0005]

The object of the present invention is to provide a copolymerized polyester component having a higher dissolution rate in an alkaline solvent as a sheath component, and a polyester component having a lower dissolution rate than the sheath component as a core component. 5.5 g / d strength
The screen gauze made of the core-sheath type composite monofilament can be achieved by dissolving and removing the sheath component with an alkaline solvent.

In the present invention, the sheath component polyester is rapidly reduced in the weight reduction treatment, but the core component polyester is hardly reduced. Therefore, the sheath component can be uniformly and rapidly dissolved and removed under conditions that do not damage the core polyester by weight loss. For this reason, the mechanical characteristics of the screen gauze after the weight reduction treatment are sufficiently maintained, and a screen gauze with excellent quality without breakage at the time of gauging can be obtained. Here, the weight loss rate ratio between the core component and the sheath component depends on the weight reduction conditions, but the core component is adjusted to be at least 1: 2, preferably at least 1: 5 by weight reduction treatment with 98% C. 3% caustic soda solution. And the polymer of the sheath component.

[0007] a reduction treatment in the present invention is aimed at removal of monounsaturated <br/> Iramento sheath component preferably kept to a few percent or less of the weight loss for the core component. If the weight loss rate of the core component exceeds several percent, the uniformity of the weight loss rate is impaired. In addition, the strength retention of the screen gauze decreases. The screen gauze of the present invention is characterized in that the substantial weight loss rate can be set by the compounding ratio of the sheath component, so that the unevenness of the weight loss rate can be extremely small. The composite ratio of the sheath component is not particularly limited, but is preferably 5 to 50%. More preferably, it is 5 to 30%. If it is less than 5%, the improvement in ink permeability is insignificant.
Although the opening area becomes large and the ink passage property is remarkably improved, misalignment tends to occur at the point where the warp yarns cross, which is not preferable.

The alkaline solvent in the present invention is a solvent mainly composed of caustic soda, and at least 50% by weight of a solute component is caustic soda. In addition, caustic potash, other inorganic alkali compounds, and quaternary ammonium salts. Alkaline salts may be contained, and those obtained by dissolving those solutes in water can be suitably used.

In the present invention, the concentration, temperature, etc., in the weight reduction treatment with an alkaline solvent are not particularly limited, but the alkali concentration is usually about 3%, and the range of the treatment temperature from 98 ° C. to the boiling point is preferable for production control. . As the core component polyester of the present invention, polyethylene terephthalate, polyethylene-2,6-naphthalate and the like are preferably used because they can have high strength and high elastic modulus and are excellent in dimensional stability.

In the composite monofilament of the present invention, its mechanical properties such as strength and elastic modulus are controlled by the core component. Therefore, it is preferable that the molecular weight of the polymer of the core component is as high as possible. For example, in the case of polyethylene terephthalate, the intrinsic viscosity is preferably 0.7 or more. By doing so, a core-sheath composite monofilament having a strength of 5.5 g / d or more can be obtained, and a high-mesh fabric can be produced from the beginning without impairing the operability in the weaving process, and the screen gauze shrinks. A high mesh can be achieved without causing the mesh to be formed. Therefore, a screen gauze having a uniform weave density can be obtained.

Examples of the sheath component polyester of the present invention include modified polyethylene terephthalate. By using the modified polyethylene terephthalate, the symmetry of the molecular chain is disturbed and the fiber structure becomes loose, and the rate of weight loss can be increased up to about 100 times compared with homopolyethylene terephthalate by treatment with caustic soda or the like. Such modified polyethylene terephthalate, for example, when polymerizing polyethylene terephthalate, isophthalic acid, adipic acid, dimeric acid, dicarboxylic acids such as 5-sodium sulfoisophthalate, diethylene glycol, low molecular weight glycols such as butanediol, polyethylene glycol And a third component such as a polyalkylene glycol such as polytetramethylene glycol, and copolymerized. In particular, it is preferable to use a modified polyester obtained by copolymerizing polyethylene glycol or polytetramethylene glycol as the sheath component, because it has high strength and generates less scum during weaving. The amount of the third component is not particularly limited. In addition, polyethylene -2,6-
When naphthalate is used, polyethylene terephthalate can be used as a sheath. Since the screen gauze of the present invention can selectively dissolve a certain amount of the sheath component, uniform weight reduction can be performed, and the core component polyester after the weight reduction can be reduced in damage, so that the strength retention is high, and The weight reduction rate can be set by the compound ratio, and a screen gauze having excellent ink passage properties can be designed.
Further, film-like or lint-like scum generated during weaving and woven into screen gauze can be completely removed.

Next, the effects of the present invention will be described with reference to the drawings.
The broken line in FIG. 1 is a weight loss curve of the core component (A), and the solid line is a weight loss curve of the sheath component (B). In the screen gauze made of the core-sheath composite yarn of the present invention, for example, a weight loss process such as 0ab can be taken, so that the sheath component (B) can be weight-removed and removed in a short time, and the sheath component (B). After the point "a" is removed, the core component (A) has a slow weight loss rate, so that an extremely uniform weight loss rate can be obtained. Further, in the present invention, the strength of the composite monofilament,
Since the core component (A) is mainly responsible for the elastic modulus, dimensional stability, etc., the reduction in mechanical properties is small and uniform even when the sheath component is removed by weight reduction.

In the present invention, there is no particular limitation on which of the screen gauze processing step and the plate making step the weight reduction processing is performed. That is, it can be carried out in any of the steps such as the scouring step, before the dyeing step, and after the plate making step.
In particular, using a beam dyeing machine to perform weight reduction, followed by dyeing and washing with a conventional method, and then applying a finishing set, uniform weight loss is high, and the problem of misalignment due to weight reduction is also prevented. Is preferred.

[0014]

【Example】

Examples 1 to 3 and Comparative Examples 1 and 2 Polyethylene terephthalate (A) having an intrinsic viscosity [η] of 0.80 was prepared as a core component of a composite monofilament. On the other hand, polyethylene glycol having a molecular weight of 1,000 was used as a sheath component during polymerization of polyethylene terephthalate.
A polymer (B) having an intrinsic viscosity [η] of 0.70 added by weight% was prepared. Using the above polymer, concentric circular composite monofilaments having different composite ratios, with A as a core and B as a sheath, were spun at 1000 m / min at a spinning temperature of 295 ° C. in accordance with a conventionally known composite spinning method. The obtained undrawn polyester monofilament is heated at 90 ° C and 140 ° C.
Using a pair of hot rolls heated to ℃, it was stretched 4.4 times to obtain a stretched monofilament having a fineness of 7 denier. Table 1 shows the composite ratio and yarn properties of the drawn monofilament.

[0015]

[Table 1]

Even when the monofilament was used, a weaving length of 500 m was woven by a Sulzer loom, and the weavability was evaluated from the scum adhesion to the wings and the breakage of the warp or weft yarn. Next, scouring and setting were performed by a conventional method to obtain a high-mesh gauze of 500 mesh. The opening area of this gauze was 23%. FIG. 1 shows the relationship between the weight loss time and the weight loss rate when the mesh gauze was heated at a bath temperature of 98 ° C. and a 3% caustic soda solution at a bath ratio of 1:50 using a beam dyeing machine. Based on the results shown in FIG. 1, the screen gauze was subjected to weight reduction by the above-described method, and after washing with water, a finish setting was performed at 160 ° C. by a conventional method to prevent misalignment. Table 2 shows the weaving properties, the weight loss treatment conditions, and the strength retention after the finish setting. Weight loss corresponding to composite ratio of sheath for Examples 1-3
It is understood that the sheath component has been dissolved and removed.
Next, a gauze frame is stretched with a high tension at a 22.5 degree angle, and a UV curable masking resin of polyvinyl alcohol and polyvinyl acetate is applied, and 100 mm × 100 m.
0.1mm line width in the squeegee running direction in a square of m
Exposure baking was performed so that 300 thin line patterns having a length of 80 mm were formed at equal intervals and washed with water to produce a screen plate. Using the screen plate, an ultraviolet-curable etching resist ink AS-400 manufactured by Taiyo Ink Manufacturing Co., Ltd.
Was used as a printing ink, and after printing was repeated 1000 times on paper, a thin line pattern was printed on copper thin. Subsequently, the copper thin film was irradiated with ultraviolet light to cure the ink, and then subjected to an optical microscope magnification of 5.
At 0x, all the faint and broken portions of the fine ink lines were counted. The results are shown in Table 3.

[0017]

[Table 2]

[0018]

[Table 3]

As is clear from the results shown in Tables 1, 2 and 3, the screen gauze made of each monofilament of Examples 1, 2 and 3 according to the present invention has good weaving properties and is made of caustic soda. The weight loss treatment is also uniform, so even if the weight loss rate is increased, it has a high strength retention rate,
The screen gauze had excellent ink passage properties and had very few printing defects even in fine line printing with a line width of 0.1 mm. Comparative Example 1 has high strength and high Young's modulus yarn properties, but when weaving into screen gauze, scum in the form of film or lint due to scraping is remarkable, and warp yarn breakage occurs in part. There was a problem. Further, in the weight reduction process using caustic soda, there are problems that the weight reduction speed is slow, the weight reduction process requires a long time, and the strength retention rate by the weight reduction process is small. Furthermore, the ink passage property was such that both the blurred portion and the broken portion of the printed fine line were present, and had a printing defect. Further, the screen gauze of Comparative Example 2 had a problem that the strength was greatly reduced due to the caustic soda treatment, and thus the yarn was easily broken during printing.

[0020]

[Effect of the Invention] Even with a high mesh screen gauze, an opening area can be secured with high accuracy, and a printing screen gauze with good ink permeability can be obtained. Further, since the thickness of the gauze can be easily reduced, the amount of expensive ink used can be reduced.

[Brief description of the drawings]

FIG. 1 shows the relationship between the weight reduction processing time and weight reduction rate of a screen gauze made of a core-sheath composite monofilament,
The solid line in the figure is the weight loss curve of the sheath component (B), and the broken line is the weight loss curve of the core component (A).

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI // D06M 101: 32 (56) References JP-A-63-233295 (JP, A) JP-A-62-220391 (JP, A) JP-A-56-49018 (JP, A) JP-A-63-315667 (JP, A)

Claims (1)

(57) [Claims] (1) A strength in which a copolymerized polyester component having a higher dissolution rate in an alkaline solvent is used as a sheath component, and a polyester component having a lower dissolution rate than the sheath component is used as a core component.
Method for producing a printing screen gauze, wherein the this <br/> to dissolve and remove the sheath component of the screen mesh with an alkaline solvent consisting of 5 g / d or more core-sheath type composite monofilament.