JP2006240011A - Mesh for screen printing and original plate for screen printing formed by using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mesh for screen printing of which the photosensitive material has a sharp edge portion and which is thus capable of reproducing an original image film with high precision and enables attainment of very excellent resolution. <P>SOLUTION: The mesh for screen printing comprises black synthetic fibers to which an ultraviolet absorber and a dye are attached, and an original plate for screen printing comprises this mesh and a photosensitive material layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a screen printing mesh. More specifically, the present invention relates to a screen printing mesh having improved resolution, and a screen printing original plate using the mesh.

  In recent years, in the printing of electronic component substrates such as various display devices such as a printed circuit, an IC circuit, or a plasma display, screen printing is frequently used because of the simplicity of the plate making method. Conventionally, as a screen plate in the above-mentioned screen printing, a photosensitive resin film of about 1 to 200 μm, for example, is formed on one side of a printing mesh composed of synthetic fiber cocoons such as polyester, nylon, and polyarylate. Use a screen plate that is formed by forming a desired pattern with a resin film on a printing mesh with moderate flexibility by developing an image film on the surface and exposing the resin film by ultraviolet irradiation. Was. The screen printing mesh formed from synthetic fibers has excellent light transmission, so the photocuring material on the back side (squeegee side) of the screen printing plate has good curability and is relatively inexpensive. Widely adopted. However, since conventional synthetic fibers easily diffuse light, irregular reflection of light occurs even when the photosensitive material is exposed, and the photosensitive material in a region that does not need to be cured is also cured. Therefore, when printing was performed using this screen, unevenness occurred in the edge portion of the cured photosensitive material, and the original image film could not be reproduced with high accuracy. That is, the synthetic fiber screen has a problem in resolution. Further, in order to reduce the influence of irregular reflection, measures have been taken to shorten the exposure time. However, in this case, the photosensitive material is not sufficiently cured and the printing durability is insufficient.

  It has been found that the wavelength of a general light source actually used in a screen printing plate is in the vicinity of 300 to 450 nm, and particularly, the light emission in the vicinity of 375 nm and 420 nm is strong. These are also the photosensitive wavelength regions of photosensitive materials used in screen printing plates.

  Therefore, in order to solve these problems, a screen in which synthetic fibers are colored in yellow has been used. However, although it suppresses reflection in the vicinity of 400 to 450 nm due to the characteristics of the absorption wavelength, it is sufficient for preventing reflection of less than 400 nm. Preventive effect cannot be obtained. In order to make up for the drawbacks, a UV screen is additionally provided to the yellow screen to suppress reflection at 280 to 450 nm, but it has been found that a screen having such characteristics is insufficient. . The cause of this is due to the wavelength conversion action that has been clarified in recent years, and light other than the original wavelength is generated, which affects the photosensitivity. That is, a characteristic that suppresses reflection of all wavelengths from the ultraviolet region to the visible light region is required.

  Patent Document 1 describes a screen printing mesh in which synthetic fibers such as polyester and nylon are colored black. However, the synthetic fiber has a unique property of reflecting a wavelength of 200 to 400 nm, and even if it is black, it has not yet been completely suppressed.

  On the other hand, there are screens colored with pigments. In general, a colorant that does not dissolve in water or oil is defined as a pigment. However, when colored with a pigment, the transmission of light is completely suppressed. The photosensitive material on the back surface (squeegee surface) of the printing plate did not cure, which was a cause of poor performance.

  Patent Document 2 proposes a composite monofilament in which the core portion is made of polyester and the sheath portion is made of polyamide because the ease of coloring, the printing durability of the coloring pigment, and the strength and dimensions can be maintained. However, the composite filament is expected to greatly increase the cost, and when the polyester in the core part existing in order to maintain the strength and dimensions becomes thin, it cannot actually maintain sufficient strength and dimensions. Moreover, when the polyester core is thickened to maintain strength and dimensions, the polyamide in the sheath is relatively thin. Although UV absorbers, pigments, and dyes are imparted to polyamide, the required performance cannot be exhibited even if these are imparted to a thin sheath.

In addition, when applying UV absorbers, pigments, and dyes to the polyamide in the sheath, a simple method of simple mixing or coloring of the stock solution has been shown. can not cut. For example, since an ultraviolet absorber has a property of sublimating at a temperature of about 100 ° C., it is difficult to mix and color the stock solution. Even if pigments and dyes are applied at low temperatures, it is difficult to withstand the friction and temperature normally used in the printing field.
JP-A-10-119447 Japanese Patent No. 2603481

  In order to improve the resolution of the screen plate using a screen printing mesh formed from synthetic fibers, in the entire ultraviolet region to the visible light region, that is, in the range of 200 to 760 nm, particularly the emission wavelengths of the light source around 375 nm and 420 nm, and Light reflection and diffuse reflection are suppressed in the vicinity of 700 nm in the long wavelength region of visible light, and the durability needs to be at the same level as the current synthetic fiber. This not only improves the resolution, but also enables exposure in a necessary and sufficient time, sufficiently cures the photosensitive material, and improves the printing durability. Moreover, in order to harden the squeegee surface, it is necessary to maintain necessary and sufficient light transmittance.

The present invention is to solve the above-described problems.
Therefore, the screen printing mesh according to the present invention is characterized by comprising black synthetic fibers to which an ultraviolet absorber and a dye are added.

  Such a screen printing mesh according to the present invention contains, as a preferred embodiment, one in which the synthetic fiber is at least one selected from polyester and polyarylate.

  Such a screen printing mesh according to the present invention contains, as a preferred embodiment, one in which the synthetic fiber is a monofilament.

  Such a screen printing mesh according to the present invention contains, as a preferred embodiment, an ultraviolet absorber that absorbs ultraviolet rays having a wavelength of 300 to 380 nm.

  In such a screen printing mesh according to the present invention, as a further preferred embodiment, the ultraviolet absorber comprises a benzotriazole compound, a chlorobenzotriazole derivative, a benzophenone compound, a benzoate compound, a hydrazine compound, and a triazine compound. Containing at least one selected from the group.

  The screen printing mesh according to the present invention is treated at a temperature of 100 ° C. or higher when the ultraviolet absorbent and the dye are applied to the synthetic fiber so that the ultraviolet absorbent and the dye are exhausted and firmly adhered to the synthetic fiber. It is characterized by that.

  Such a screen printing mesh according to the present invention preferably has a reflection of 375 nm, which is a main absorption wavelength of a general photosensitive material used for a screen printing plate, in a state where 16 screen printing meshes are stacked. The rate is 30% or less, preferably 20% or less, compared to a raw screen printing mesh not provided with UV absorber and dye.

  Such a screen printing mesh according to the present invention has, as a preferred embodiment, a reflectance in the vicinity of a main wavelength of 420 nm of a general light source used in a printing plate for screen printing in a state where 16 screen printing meshes are stacked. , 20% or less, preferably 10% or less, as compared to a raw screen printing mesh not provided with an ultraviolet absorber and dye.

  In such a screen printing mesh according to the present invention, as a preferred embodiment, in the state where 16 screen printing meshes are stacked, the reflectance of a general light source used in a screen printing plate is around 700 nm. , 40% or less, preferably 30% or less, compared to a raw screen printing mesh not provided with an ultraviolet absorber and dye.

  A screen printing original plate according to the present invention comprises any one of the screen printing meshes described above and a photosensitive material layer.

Unlike conventional black screens, the screen printing mesh made of synthetic fibers with UV absorbers and dyes according to the present invention absorbs light in the ultraviolet region and reflects not only the hue of black but also the reflection of important wavelengths. By specifying the rate, effective performance can be exhibited. That is, since reflection of light is suppressed at 200 to 760 nm, particularly around 375 nm and 420 nm, which are emission wavelengths of the light source, and around 700 nm in the long wavelength region of visible light, irregular reflection of light during exposure can be prevented. In addition, since the dye is used, the necessary and sufficient light transmittance is maintained, so that the squeegee surface is cured at the same level as that of the conventional fiber and is excellent.
Since the ultraviolet absorber and the dye are exhausted firmly inside the synthetic fiber, they are also durable.

  Since the synthetic fiber is a monofilament, the low cost, high strength, and processability are also good. Further, if heat treatment is performed with dry heat of 180 ° C. or higher before applying the ultraviolet absorber and the dye, shrinkage does not occur in the subsequent steps, and final printing is possible while maintaining the original shape and density.

  Therefore, when developed with the screen printing original plate according to the present invention comprising the screen printing mesh and the photosensitive material layer, the edge portion of the cured photosensitive material is sharp and the original image film can be reproduced with high accuracy and resolution. Is extremely excellent.

<Mesh for screen printing>
The screen printing mesh according to the present invention is characterized by comprising synthetic fibers provided with an ultraviolet absorber and a dye. Here, “providing an ultraviolet absorber and a dye” means exhausting or impregnating the ultraviolet absorber and the dye on the surface and inside of the synthetic fiber molecule. The UV absorber can be applied by the same or similar method as a general UV absorber, and the dye can be applied by the same or similar method as general dyeing. By these methods, both an ultraviolet absorber and a dye can be applied.

Synthetic fiber As the synthetic fiber in the screen printing mesh according to the present invention, those conventionally used as this kind of screen printing mesh can be used. In the present invention, at least one selected from polyester and polyarylate is preferable. Polyester fibers are preferred in terms of cost and quality. Furthermore, it is preferably a monofilament, and has lower cost, higher strength, and better workability than the composite filament. Ultraviolet absorbers and dyes can also be exhausted over the entire area of the yarn, resulting in higher performance than composite filaments that can only be applied to the surface.

  The fiber diameter of the synthetic resin fiber and the woven density of the screen printing mesh are arbitrary. For example, the fiber diameter is 10 to 500 μm, particularly 20 to 300 μm, and the woven density is preferably 10 to 600 mesh, particularly 80 to 500 mesh.

Ultraviolet absorbent A preferred ultraviolet absorbent in the screen printing mesh according to the present invention has an absorption region at a wavelength of 200 to 400 nm, preferably 300 to 380 nm. This wavelength region is the wavelength of the light source used for the screen printing plate, and is also the photosensitive wavelength region of the photosensitive material used for the screen printing plate.

  In addition, the ultraviolet absorber of this invention may absorb both the ultraviolet-ray within the said wavelength range and the ultraviolet-ray outside the said wavelength range.

  Preferable specific examples of such ultraviolet absorbers include, for example, (a) benzotriazole compounds, (b) chlorobenzotriazole derivatives, (c) benzophenone compounds, (d) benzoate compounds, (e) hydrazine compounds. Examples thereof include (f) triazine compounds. Since these compounds have maximum absorption at 300 to 380 nm, they can efficiently absorb light at 300 to 380 nm.

As the benzotriazole-based compound (i) above,
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-dodecyl-5'-methylphenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis- (α, α-dimethylbenzyl) phenyl] -benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylbenzylphenyl) -benzotriazole, 2- (2' -Hydroxy-3 ', 5'-di-t-butylphenyl) -benzotriazole,
2- (2'-hydroxy-3 ', 5'-di-t-phenyl) -benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole, 2,2'-methylene An example is -bis- [N- (1,1,3,3-tetramethylbutyl) -6- (2-N-benzotriazol-2-yl) phenol].

As the chlorobenzotriazole derivative of (b) above,
2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl)- Examples include 5-chlorobenzotriazole.

As the benzophenone-based compound (c) above,
2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid,
2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenol) Methane, 2,2'-dihydroxy-4-benzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-N, N- An example is diethyl-4′-carboxybenzophenone.

As the above (d) benzoate compound,
Phenylsalicylate, 4-t-butylsalicylate, 4-t-octylphenylsalicylate,
As the hydrazine compound of the above (e),
N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, bis-2-phenoxypropionyl hydrazide, isophthalic acid, 1,1,1 ', 1'-tetra Methyl-4,4 ′-(methylene-di-p-phenylene) disemicarbazide, alkylhydrazine derivatives, etc.
An example of the triazine compound (f) is hydroxyphenyl triazine. The present invention can be used as long as it is a general ultraviolet absorber having an absorption wavelength region of 200 to 400 nm, and is not limited thereto.

  In the present invention, two or more compounds selected from the same group of compounds classified as (b) to (f) above, and / or different groups of compounds classified as (b) to (f) above Two or more selected compounds can be used in combination.

  The applied amount of the ultraviolet absorber is preferably 0.0001 to 5% by weight, particularly preferably 0.001 to 3% by weight, based on the weight of the synthetic fiber constituting the screen printing mesh. When the applied amount is less than 0.0001% by weight, the effect is insufficient, while when it exceeds 5% by weight, it is disadvantageous in terms of cost.

Dye In the present invention, there is no limitation as a dye, and examples thereof include azo dyes and anthraquinone dyes. Typical trade names are listed below, but the dyes can be dyed in black. is not.

  CIBASET Black EL-B (Ciba SC), CIBASET Yellow 2GC (Ciba SC), CIBASET Red 2GNN (Ciba SC), CIBASET Blue F3R (Ciba SC), TERASIL Black BFA (Ciba SC), TERASIL Black MAW (Ciba SC), TERASIL Black SRL (Ciba SC), TERATOP Black RLA-02 (Ciba SC), TERASIL Yellow 4G (Ciba SC), TERASIL Red R (Ciba SC), TERASIL Blue BGE-01 (Ciba SC), Dianix Black SR (Dystar) , Dianix Black SE-G (Dystar), Dianix Black EG (Dystar), Dianix Black KB (Dystar), Dianix Black AM-B (Dystar), Dianix Black S-LF01 (Dystar), Dianix Black HF-B (Dystar) , Dianix Black AD-R (Dystar), Dianix Black KIT-FS (Dystar), Dianix Yellow S-6G (Dystar), Dianix Red S-2B (Dystar), Dianix Blue S-2G (Dystar), Dianix Orenge Plus ( Dystar), Mikeron Polyester Black GNSF (Dystar), Mikeron Polyester Black RBSF (Dystar), Mikeron Polyester Black GE (Dystar), Mikeron Polyester Black GWB (Dystar), Mikeron Polyester Black RCS (Dystar), Mikeron Polyester Black PBSF (Dystar) , Mikeron Polyester Black GCS (Dystar), Mikeron Polyester Yellow 5G (Dystar), Mikeron Polyester Red BSF (Dystar), Mikeron Polyester Blue 3RT (Dystar), Kayalon Polyester Black TN200 (Nippon Kayaku), Kayalon Polyester Black BRN-SF200 (Nippon Kayaku), Kayalon Polyester Black EX-SF200 (Nippon Kayaku), Kayalon Polyester Black EX-SF300 (Nippon Kayaku) Kayalon Polyester Black ECX300 (Nippon Kayaku), Kayalon Polyester Yellow 4G-E (Nippon Kayaku), Kayalon Polyester Red BR-S (Nippon Kayaku), Kayalon Polyester Blue 2R-SF (Nippon Kayaku)

  The addition amount of the dye is preferably 0.1 to 30% by weight, particularly 1 to 20% by weight, based on the weight of the synthetic fiber constituting the screen printing mesh. If the applied amount is less than 0.1% by weight, the effect is insufficient, while if it exceeds 30% by weight, it is disadvantageous in terms of cost.

  In the present invention, all the dyes including the dyes described above can be used alone or in combination of two or more.

  The screen printing mesh according to the present invention to which the ultraviolet absorber and the dye are added is compared with an unprocessed screen printing mesh to which the ultraviolet absorber and the dye are not applied in the state where 16 meshes are stacked. The reflectance of ultraviolet light with a wavelength of 375 nm is 30% or less, preferably 20% or less, the reflectance of light with a wavelength of 420 nm is 20% or less, preferably 10% or less, and the reflectance of ultraviolet light with a wavelength of 700 nm is 40% or less, preferably Is desirably 30% or less.

  Therefore, it is preferable to select or select the type and / or amount of the ultraviolet absorber or dye so that the reflectance is within the above range.

Application of UV absorber The application of the UV absorber is most preferably performed simultaneously with dyeing in terms of cost and quality. In this method, a necessary amount of an aqueous dispersion of an ultraviolet absorber is added to the dye dispersion, and then the dyeing process is performed to exhaust the screen soot. The amount to be added is appropriately determined in relation to the aforementioned performance.

  Although simultaneous processing with dyeing is advantageous in terms of cost, there is no problem in terms of performance even if processing is performed separately from dyeing. Further, a heat treatment method in which a dispersion of an ultraviolet absorber is attached to a screen ridge is also possible.

  If the synthetic fiber is heat-treated with dry heat of 180 ° C. or higher before applying the UV absorber, it will not shrink in the subsequent steps, and it can be used until the final printing while maintaining the original shape and density. .

  It is preferable to perform the adhesion treatment of the ultraviolet absorbent by immersing the screen printing mesh in a solution or dispersion in which the ultraviolet absorbent is dissolved or dispersed. The ultraviolet absorber adhering treatment can be performed once or twice or more. As the liquid (solvent) for preparing the ultraviolet absorbent solution or dispersion, water is suitable, but an aqueous organic solvent can be used in combination.

  The heat treatment can be carried out in a solution or dispersion of the UV absorber (that is, in the bath) or outside the liquid (that is, outside the bath), but in the present invention, the former is carried out in the liquid. It is preferable to carry out in a bath. Preferred treatment conditions in this case vary depending on the type of the synthetic fiber and the UV absorber, but the treatment temperature is 100 to 160 ° C., particularly 110 to 140 ° C., and the treatment time is 5 to 720 minutes, especially 20 to 120 minutes. Can be mentioned.

  The combination of the liquid removal treatment and the water washing treatment after treatment is arbitrary. Preferred liquid removal treatments include centrifugal dewatering, squeezing dewatering (for example, mangle dewatering by squeezing the screen between two pressurized rolls), air flow dewatering (for example, dehydration by suction or blowing of pressurized air flow, vacuum dewatering). Examples thereof include capillary dehydration utilizing water absorption by capillary force. Drying can also be performed by a normal drying method such as hot air drying.

Dye application For dyeing synthetic fibers, dyeing processing with dyes is preferred in terms of durability, uniformity, etc., and publicly known and publicly available techniques can be applied. Hereinafter, a polyester screen wrinkle will be described as an example.

  If the synthetic fiber is heat-treated with a dry heat of 180 ° C. or higher before the dye is applied, it will not shrink in the subsequent steps, and it can be used until the final printing while maintaining the original shape and density.

  For the dyeing of the polyester screen wrinkle, a publicly known dyeing technique can be applied. The dye is not particularly limited, and a known azo-type or anthraquinone-type disperse dye can be used. The type and amount of the dye is not particularly limited as long as it can be dyed black and can control the reflectances of 375 nm, 420 nm, and 700 nm below the target values.

  In the case of mesh for printing, it is not preferable to bend or wrinkle, so it is desirable to dye with a beam machine or a zicker machine that can be dyed in a spread form.

  In the heat treatment, the dye is permeated and injected into the inside of the fiber molecule by immersing the screen bottle in a dispersion liquid in which the dye is dispersed in water and treating it at a high temperature and high pressure in a sealed apparatus. In general, the treatment is preferably performed at 110 to 140 ° C. in view of the dyeing density and fastness.

  On the other hand, a so-called thermosol method in which a dye dispersion is attached and dried, followed by treatment with dry heat or wet heat for dyeing can also be used.

  The ultraviolet absorber adhering treatment can be performed once or twice or more. As the liquid (solvent) for preparing the ultraviolet absorbent solution or dispersion, water is suitable, but an aqueous organic solvent can be used in combination.

  The combination of the liquid removal treatment and the water washing treatment after treatment is arbitrary. The technique is the same as that described above when applying the ultraviolet absorber.

<Original for screen printing>
A screen printing original plate according to the present invention is characterized by comprising the screen printing mesh according to the present invention and a photosensitive material layer.

Photosensitive material layer In the present invention, it is possible to use a photosensitive material that has been conventionally used for screen printing original plates.
The thickness of the photosensitive material layer is not particularly limited, but is preferably 0.1 to 1000 μm, particularly preferably 1 to 200 μm.

  The screen printing original plate according to the present invention can be obtained preferably by forming a photosensitive material layer on the screen printing mesh, exposing it to light, and then developing it. At this time, the method for forming the photosensitive material layer, the photosensitive method for the photosensitive material layer, the processing method for the development processing, and the like are not essentially different from those conventionally used for the master plate for screen printing. Therefore, the screen printing original plate according to the present invention is formed by applying (1) a water-soluble resin containing an ultraviolet curable resin to the screen printing mesh according to the present invention, and drying to form a photosensitive material layer. 2) After an original mask prepared separately is superposed on this, (3) UV irradiation is performed to subject the photosensitive material layer in the UV transmitting portion of the original mask to curing, and (4 ) Thereafter, it can be produced by carrying out a development process comprising removing the photosensitive material of the non-photosensitive part (that is, the non-cured part) other than the ultraviolet-cured part with water or an aqueous alkali solution.

  The screen printing mesh and the screen printing original plate according to the present invention described above are those in which irregular reflection of ultraviolet rays during exposure is effectively prevented, and the necessary and sufficient light transmittance is maintained. Is excellent at the same level as conventional fibers, and can be exposed for a long time in order to obtain sufficient printing durability while maintaining resolution.

〔The invention's effect〕
Unlike conventional black screens, the screen printing mesh made of synthetic fibers with UV absorbers and dyes according to the present invention absorbs light in the ultraviolet region and reflects not only the hue of black but also the reflection of important wavelengths. By specifying the rate, effective performance can be exhibited. That is, since reflection of light is suppressed at 200 to 760 nm, particularly around 375 nm and 420 nm, which are emission wavelengths of the light source, and around 700 nm in the long wavelength region of visible light, irregular reflection of light during exposure can be prevented. In addition, since the dye is used, the necessary and sufficient light transmittance is maintained, so that the squeegee surface is cured at the same level as that of the conventional fiber and is excellent.
Since the ultraviolet absorber and the dye are exhausted firmly inside the synthetic fiber, they are also durable.

  Since the synthetic fiber is a monofilament, the low cost, high strength, and processability are also good. Further, if heat treatment is performed with dry heat of 180 ° C. or higher before applying the ultraviolet absorber and the dye, shrinkage does not occur in the subsequent steps, and final printing is possible while maintaining the original shape and density.

  Therefore, when developed with the screen printing original plate according to the present invention comprising the screen printing mesh and the photosensitive material layer, the edge portion of the cured photosensitive material is sharp and the original image film can be reproduced with high accuracy and resolution. Is extremely excellent.

(Synthetic fibers)
A # 300 polyester bag heated at 200 ° C. for 30 seconds with hot air was used.

(Drug)
2,4-dihydroxybenzophenone, Mikeron Polyester Black PBSF (Dystar), DIANIX ORANGE PLUS (Dystar) were used.

(Prescription)
Treated with the 20 formulations listed in Table 1.

(Processing method)
The application of the ultraviolet absorber was performed simultaneously with the dyeing. That is, 2,4-dihydroxybenzophenone, Mikeron Polyester Black PBSF (Dystar), and DIANIX ORANGE PLUS (Dystar) were simultaneously added, and the screen printing mesh was immersed in the solution, followed by heat treatment at 130 ° C. for 2 hours. .
The liquid removal after the treatment was performed by mangle dewatering by squeezing a screen bottle between two pressurized rolls, followed by hot air drying at 180 ° C. for 30 seconds.

(Reflectance measurement method)
The reflectances of 375 nm, 420 nm, and 700 nm of each screen were measured in a state where 16 screen printing meshes were stacked. The value was expressed as a relative value with respect to the reflectance of the untreated screen (Comparative Example 1).
Furthermore, the reflectance was also measured under conditions where the angle between incident light and reflected light was 30 degrees. This is an indicator of diffuse reflection. Similarly to the above, the wavelengths of 375 nm, 420 nm, and 700 nm were measured in a state where 16 screen printing meshes were stacked, and the value was defined as 100% of the reflectance of the untreated screen wrinkle (Comparative Example 1). The relative value with respect to was described.

(Reflectance measurement result)
The screen cage to which Mikeron Polyester Black PBSF (Dystar) was added tended to have a lower reflectance than Comparative Example 1 at all wavelengths. Although the 30-degree reflectance also tended to decrease, it was estimated that there was irregular reflection in the ultraviolet region, not a significant decrease at 375 nm.
When 2,4-dihydroxybenzophenone, which is an ultraviolet absorber, was added thereto, the reflectance tended to further decrease. In particular, the 30-degree reflectivity at 375 nm in the ultraviolet region was suppressed to less than half, and it was estimated that irregular reflection was also suppressed (Examples 1 to 3 versus Comparative Examples 2 to 4).

(Resolution evaluation method)
The screen printing mesh obtained above was subjected to platemaking evaluation by the following method. That is, the treated screen wrinkle (300 mesh, wire diameter 34 μm) is stretched as usual, and an SBQ-type direct-film film having a film thickness of 15 μm is exposed to a 3 Kw metal halide lamp every 20 seconds. The film was exposed to light and developed with spray water. The developed plate was observed with a magnifying glass, and the exposure time and resolution were evaluated. The resolution was measured by measuring the width of the fine line after development. The target thin line width is 40 μm. The results are shown in Table 2.

(Result)
The untreated screen has a fine line width of 50 μm, which is thicker than the target even when the exposure time is 20 seconds, and it is difficult to print with high accuracy. In addition, although the exposure time of a general black dyeing and orange dyeing screen can be longer than that of the unprocessed screen, only a comparative example 5 is possible if a target fine line of 40 μm is to be drawn with a normal exposure time of 60 seconds. However, since the amount of the dye used in Comparative Example 5 is large, it affects the cost and is not appropriate.
Looking at the results of Examples in which an ultraviolet absorber was added thereto, in Examples 1, 2, and 3, a target fine line of 40 μm can be drawn with a normal exposure time of 60 seconds, and there is no problem in terms of cost under these manufacturing conditions.

(Evaluation of squeegee surface)
A screen original plate using the screen of Comparative Example 1, a screen original plate using the screen of Example 3, and a screen original plate using a 300-mesh stainless steel plate having the same density were used. The film was stretched as usual, and an SBQ-type direct film having a film thickness of 15 μm was exposed with a 3 Kw metal halide lamp for 60 seconds. Then, an electron micrograph of the squeegee surface (the back side of the screen plate) was taken, and the degree of curing of the photosensitive material was visually observed.

(Evaluation results)
As for the screen original plate using the screen of Example 3, the squeegee surface (the back side of the screen plate) was cured similarly to that of Comparative Example 1, and it was confirmed that the screen had sufficient and sufficient light transmittance. The squeegee surface had a poor curability when the screen was made of stainless steel. It was confirmed that the product of the present invention was able to maintain the fiber-specific performance even after the UV absorber and dye were applied.

The electron micrograph which shows the squeegee surface of the screen original plate using the screen of the comparative example 1. FIG. The electron micrograph which shows the squeegee surface of the screen original plate using the screen of Example 3. FIG. An electron micrograph showing a squeegee surface of a screen original plate using a stainless steel basket.

Claims (10)

  A mesh for screen printing, comprising a black synthetic fiber to which an ultraviolet absorber and a dye are added.   The screen printing mesh according to claim 1, wherein the synthetic fiber is at least one selected from polyester and polyarylate.   The screen printing mesh according to claim 1, wherein the synthetic fiber is a monofilament.   The mesh for screen printing of any one of Claims 1-3 whose absorption wavelength range of a ultraviolet absorber is 300-380 nm.   The ultraviolet absorber is at least one selected from the group consisting of benzotriazole compounds, chlorobenzotriazole derivatives, benzophenone compounds, benzoate compounds, hydrazine compounds, and triazine compounds. The mesh for screen printing of any one of Claims 1.   The screen printing mesh according to any one of claims 1 to 5, which is treated at a temperature of 100 ° C or higher when the ultraviolet absorbent and the dye are applied to the synthetic fiber.   In the state in which the 16 screen printing meshes are stacked, the reflectance at a wavelength of 375 nm is 30% or less, preferably 20%, as compared with the raw screen printing mesh not provided with the ultraviolet absorber and the dye. The mesh for screen printing of any one of Claims 1-6 which is the following.   In a state where 16 screen printing meshes are stacked, the reflectance at a wavelength of 420 nm is 20% or less, preferably 10%, as compared with a raw screen printing mesh not provided with an ultraviolet absorber and a dye. The mesh for screen printing of any one of Claims 1-7 which is the following.   In a state where 16 screen printing meshes are stacked, the reflectance at a wavelength of 700 nm is 40% or less, preferably 30%, as compared with an unprocessed screen printing mesh not provided with an ultraviolet absorber and a dye. The mesh for screen printing of any one of Claims 1-8 which is the following.   A screen printing original plate comprising the screen printing mesh according to any one of claims 1 to 9 and a photosensitive material layer.