JP2002293049A - Resin relief printing plate for forming thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin relief printing plate for forming a thin film by which a marginal phenomenon is prevented from being generated and an oriented film with a uniform film thickness can be formed. SOLUTION: In the resin relief printing plate for forming the thin film used for transferring a coating liquid applied on projected parts 2 for printing onto a body to be printed and printing, channel parts 4 for holding the coating liquid are formed among adjoining micro-projections 3 by distributing and forming a number of the micro-projections 3 on the whole face of the projected parts 2 for printing. In addition, in the central regions X of the projected parts 2 for printing, the adjoining micro-projections 3 are uniformly formed and in the peripheral regions Y of the projected parts 2 for printing, distribution densities of the micro-projections 3 are higher than those of the central regions X. In addition, the occupied area ratio of the micro-projections 3 becomes gradually higher as the regions approach toward the end parts in the peripheral regions Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin relief plate for forming a thin film capable of forming an alignment film having a uniform thickness on an electrode forming surface of a liquid crystal display element substrate.

[0002]

2. Description of the Related Art Resin relief printing plates have been used for various printings. In particular, in recent years, when manufacturing a liquid crystal display device, a relief printing method using a resin relief printing plate is used to print an alignment film for forming an alignment layer. In particular,
In order to print and form an alignment film made of a polyimide resin on the surface of a glass substrate, a resin relief plate made of a photocurable resin is widely used. Then, using the resin relief plate, two glass substrates on which an alignment film made of polyimide resin is formed by printing are prepared, laminated so that the alignment films made of polyimide resin face each other, and Liquid crystal is sealed in the gap, and a liquid crystal display device is manufactured.

[0003] The alignment film using the resin relief printing plate is formed by printing, for example, through the following steps. First, a resin relief printing plate having a groove for holding a uniform amount of the coating liquid over the entire surface of the printing projection is prepared.
The groove is formed by providing minute projections of uniform size and distribution density on the surface of the printing projection. Then, a coating liquid of a polyimide resin is applied to the entire surface of the printing projection to hold the coating liquid on the surface of the printing projection, and then the coating liquid is transferred to a glass substrate. . After the transfer, drying is performed to remove the solvent, followed by baking, so that an alignment film made of a polyimide resin having a size corresponding to the surface of the printing projection is formed on the glass substrate.

The polyimide resin alignment film formed by printing on the glass substrate as described above is required to have a uniform film thickness. That is, recently, in order to achieve higher gradation display and higher contrast in the liquid crystal display device, extremely high uniformity is also required for the alignment film itself, and the thickness of the polyimide resin alignment film is not uniform. Even a slight change in thickness causes problems such as a gap defect, a change in threshold voltage, and unevenness in display color.

[0005]

However, as described above, a polyimide resin alignment film formed by printing with a resin relief plate having fine projections uniformly distributed on the printing projections is smaller than the central region thereof. Therefore, the phenomenon that the thickness of the peripheral region is increased has occurred. This is due to the following reasons. That is, usually, the resin relief printing plate is mounted on the surface of a printing press plate cylinder (drum), a coating liquid is supplied thereto, and the coating liquid is transferred to a glass substrate at a predetermined rotation speed and pressing pressure. In accordance with the rotation of the plate cylinder, the coating liquid staying in the central portion of the printing convex portion of the resin relief printing plate gathers at the peripheral portion, the amount of the coating liquid increases at the peripheral portion, and a liquid pool occurs. This causes a phenomenon that the thickness of the peripheral portion of the obtained alignment film is increased (hereinafter, referred to as “marginal phenomenon”). For example, a thickness of 300 to 900
The alignment film to be formed to have a thickness of {circle around (1)} is formed to be as thick as about 1200 to 1800 ° at the periphery thereof. In order to solve such inconveniences, various methods have conventionally been attempted, such as designing a pattern shape of a printing convex portion, and improving a printing machine by automatically adjusting a printing stage scanning speed and a coating liquid concentration. However, the fact is that it has not been solved yet.

The present invention has been made in view of such circumstances, and suppresses the occurrence of the marginal phenomenon, and forms an alignment film having a uniform thickness even at the peripheral portion of the printing projection at the central portion. It is an object of the present invention to provide a resin relief plate for forming a thin film that can be used.

[0007]

Means for Solving the Problems In order to achieve the above object, the resin relief plate for forming a thin film of the present invention is used for transferring and coating a coating liquid applied to a printing projection onto a printing substrate. A thin film forming resin relief plate, in which a large number of fine protrusions are distributed and formed on the entire surface of the printing convex portion, so that a groove portion for holding the coating liquid is formed between adjacent fine protrusions. In the central region of the printing projection, adjacent microprojections are formed at equal intervals, and in the peripheral region of the printing projection, the distribution density of the microprojections is formed higher than the central region, and The configuration is such that the occupation area ratio of the minute projections gradually increases toward the end of the region.

That is, the present inventors have conducted a series of studies in order to obtain a resin relief plate capable of forming an alignment film having a uniform film thickness while suppressing the occurrence of the marginal phenomenon. And
First, as a result of repeated studies on the cause of the marginal phenomenon, it was found that the cause was as described above, and a resin relief printing relief that could suppress the liquid pool of the coating liquid on the peripheral edge was found. Further research was conducted mainly on the microprojection pattern of the part. As a result, in the central region of the printing convex portion, adjacent fine protrusions are formed at equal intervals, and in the peripheral region of the printing convex portion, the distribution density of the fine protrusions is formed higher than the central region, and The present invention has been found that, when the occupation area ratio of the microprojections is gradually increased toward the end in the peripheral region, the occurrence of the marginal phenomenon is suppressed, and an alignment film having a uniform film thickness can be obtained. Reached.

The ratio [(Y) / (X)] of the distribution density (Y) of the fine projections in the peripheral area of the printing projection and the distribution density (X) of the fine projections in the central area of the printing projection. Is set to a specific range, the occurrence of the marginal phenomenon can be further suppressed, and an alignment film having a uniform film thickness can be formed.

Further, the fine projections are formed in a truncated conical shape or a cylindrical shape, and the diameter of the fine projections in the peripheral area of the printing projection is smaller than the diameter of the fine projection in the central area of the printing projection.
By setting a specific ratio for each of the diameter of the microprojections near the center area and the diameter of the microprojections near the end of the peripheral area, the occurrence of the marginal phenomenon is further suppressed, and the uniform film is formed. A thick alignment film can be formed.

[0011]

Next, embodiments of the present invention will be described in detail.

An example of the resin relief plate for forming a thin film of the present invention will be described. As shown in FIG. 1, the entire resin relief plate 1 has a square shape, and a printing projection 2 is provided at the center thereof. As shown in FIGS. 2 and 3, a large number of fine projections 3 are distributed and formed on the entire surface of the printing convex portion 2, and a coating liquid for forming an alignment film is held between the adjacent fine projections 3. Groove 4 is formed. The above-mentioned printing projection 2
In the central region X, adjacent minute projections 3 are formed at equal intervals. On the other hand, in the peripheral region Y of the printing projection 2, the distribution density of the fine protrusions 3 is formed higher than that of the central region X, and the area occupied by the fine protrusions 3 gradually toward the end in the peripheral region Y. It is formed to have a high rate. Note that the occupied area ratio of the minute projections 3 refers to the ratio of the minute projections 3 to the total area of the minute projections 3 and the groove 4 formed between the adjacent minute projections 3.

The resin relief plate 1 for forming a thin film according to the present invention is the same as a conventional one in any of its shape, material and method of use. That is, the basic configuration of the resin relief printing plate 1 includes a printing projection 2 formed by curing a photocurable resin, and a non-printing portion 2 a that carries the printing projection 2. Then, a coating liquid is applied to the surface of the printing convex portion 2, and the coating liquid is transferred and printed on the printing medium.

The planar shape of the printing convex portion 2 is determined as appropriate, but generally, a substantially rectangular shape is often used.
Therefore, in the present invention, when the printing convex portion 2 is a quadrangle, the peripheral area Y of the printing convex portion 2 refers to a peripheral portion of each of the four sides of the quadrangle.

The range of the peripheral area Y of the printing projection 2 is as follows.
It is appropriately set depending on the size of the resin relief printing plate 1 as a whole, but is usually 0.1 to several mm from the peripheral edge of the printing projection 2.
Refers to the range of the area inside, preferably 0.1 to 1 mm
It is the area inside the degree. It should be noted that FIG.
Is a diagram schematically showing a plan view of the resin relief printing plate 1, in which a peripheral region Y is shown larger than a central region X of the printing convex portion 2, but the peripheral region Y is actually a central region. Region X
The area is very small as compared with.

The distribution density of the minute projections 3 in the peripheral area Y of the printing projection 2 is set to be higher than the distribution density of the minute projections 3 in the central area X. Specifically, the degree of the distribution density (Y) of the fine protrusions 3 in the peripheral region Y of the printing convex portion 2 and the distribution density (X) of the fine protrusions 3 in the central region X of the printing convex portion 2 is determined. Ratio [(Y) /
(X)] is preferably set to 1.2 to 2.5, particularly preferably (Y) / (X) = 1.3 to
2.3. That is, if (Y) / (X) is less than 1.2, the effect of preventing the occurrence of the marginal phenomenon is poor, and if it exceeds 2.5, on the other hand, the depth of the groove portion 4 for holding the coating liquid between the minute projections 3 is small. (Depth from the surface of the microprojections 3) is not sufficiently obtained, and a route for escaping the excess coating liquid staying in the central portion of the printing projections 2 to the outside of the projections is cut off. This is because there is a tendency to be defective.

Further, even in the peripheral region Y where the distribution density of the fine protrusions 3 is set high, the occupation area ratio of the fine protrusions 3 is set so as to gradually increase toward the end of the peripheral region Y. I have. The above “the occupation area ratio of the minute projections 3 gradually increases” means that the printing projections 2
From the occupied area ratio of the microprojections 3 near the central region X to the occupied area ratio of the microprojections 3 on the end side of the peripheral region Y in such a manner that the value of the area ratio gradually increases. That is being done. The degree of increase in the occupied area ratio includes the occupied area ratio (α) of the microprojections 3 on the end side and the occupied area of the microprojections 3 near the central region X in the peripheral region Y of the printing projection 2. Ratio of rate (β) [(α) / (β)]
Is preferably set to 1.1 to 3.3.

In the present invention, the depth of the groove 4 formed in the printing projection 2 is not particularly limited.
Although it may be formed at a substantially constant depth over the entire surface of the printing projection 2, for example, in the central region X of the printing projection 2,
Generally, the depth of the groove 4 formed by the large number of microprojections 3 is substantially constant, and is gradually reduced from the vicinity of the central region X toward the end of the peripheral region Y. .

The distance between the minute projections 3 and the depth of the groove 4 are not particularly limited, and are appropriately set. That is, these are appropriately set according to the thickness of the alignment film to be transferred and printed. For example, if the thickness of the alignment film is about 300 to 1000 °, the interval between the minute projections 3 may be in the range of about 0.03 to 0.1 mm. The depth of the groove 4 is 0.002 to 0.035 mm.
It may be within the range of the degree.

The microprojections 3 are generally formed in a truncated conical or cylindrical shape in cross section. And
The diameter of the small projections 3 in the peripheral area Y of the printing projections 2 relative to the diameter of the small projections 3 in the central area X of the printing projections 2 is 0. It is preferable that the diameter is set to be 3 times or more and less than 1.5 times, and the projection diameter of the minute projections 3 on the end side of the peripheral region Y is 1.5 times or more and less than 3.0 times. More preferably, the diameter of the minute projections 3 in the vicinity of the central area X is 0.9 times or more and less than 1.3 times, and the diameter of the minute projections 3 on the end side of the peripheral area Y is 1.6 times.
More than twice and less than 2.4 times. That is, by setting the projection diameter of the minute projections 3 in this way, when the alignment film is printed by the printing press using the resin relief printing plate 1, the coating liquid is applied in a certain direction by the printing pressure applied by the rotation of the printing press plate cylinder. Thus, an effect of uniformly dispersing the entire convex portion without staying in the convex portion can be obtained.

The arrangement pattern of the minute projections 3 formed in the peripheral area Y is different from the arrangement pattern of the minute projections 3 formed in the central area X with respect to the arrangement pattern of the minute projections 3 formed in the printing projection 2. It is preferable that the array pattern is formed so as to have an angle of 0 to 45 °. Particularly preferably, the angle is 0 to 30 °.

The resin relief plate for forming a thin film of the present invention is, for example,
It can be manufactured as follows. That is, first, in the region corresponding to the printing convex portion of the resin relief printing plate, the portion corresponding to the minute projection is transparent, and the portion corresponding to the groove portion and the region other than the printing convex portion (non-printing region) are black. Prepare a negative film. Then, a liquid photocurable resin is applied on the negative film so as to have a constant thickness to form a liquid photocurable resin layer. After forming the layer, a transparent film (base film) is formed on the liquid photocurable resin layer.
Then, light irradiation is performed through this transparent film to cure the liquid photocurable resin, thereby producing a non-printed portion of a resin relief printing plate. Next, by performing light irradiation through the negative film, a printing convex portion of the resin relief printing plate is formed, and a large number of minute projections and a groove portion provided by the minute projection are formed in the printing convex portion. . Then, the uncured resin is washed and removed, dried, and further exposed to light (post-exposure) by light irradiation to produce a resin relief printing plate.

As the resin relief plate for forming a thin film of the present invention, a base film layer and a pressure-sensitive adhesive are provided on the opposite side (rear side) of the resin relief plate obtained as described above from the printing projection forming surface. An adhesive layer made of an agent or the like, a metal plate or a synthetic resin plate may be laminated in this order. By using the resin relief printing plate having such a configuration, a cupping phenomenon (a phenomenon in which the peripheral region of the printing protrusion of the relief printing material itself is formed thicker than the central region) is less likely to occur, and as a result, a marginal phenomenon occurs. Can be effectively suppressed.

The liquid photocurable resin is not particularly limited as long as it is conventionally known. Examples thereof include those obtained by adding a photosensitizer or a heat stabilizer to an unsaturated polyester resin or polybutadiene. Alternatively, a prepolymer such as acryl, urethane, epoxy, or polyester obtained by adding a photosensitizer or a heat stabilizer to an unsaturated resin having an unsaturated group introduced therein is used. Further, the photo-curable resin is not limited to the liquid described above, and may be a solid such as a plate. Specific examples include APR (manufactured by Asahi Kasei Corporation), AFP (manufactured by Asahi Kasei Corporation), Tevista (manufactured by Teijin Limited), and the like.

In the resin relief plate for forming a thin film of the present invention, the pattern formation of the characteristic minute projections of the printing projections includes the transparent portion corresponding to the minute projections of the negative film and the black portion corresponding to the groove. By making appropriate adjustments, a desired pattern of minute projections can be formed. Such a negative film can be manufactured by forming a desired pattern using, for example, an image setter (image processing apparatus) for film exposure.

The formation of an alignment film, which is a thin film, using the resin relief plate for forming a thin film thus obtained is performed as follows. That is, a coating liquid for forming an alignment film is applied to the printing protrusions of the resin relief printing plate to hold the coating liquid, and then the coating liquid is transferred to a printing medium. Then, after transferring the coating liquid, by drying and removing the solvent and baking,
An alignment film having a size corresponding to the surface of the printing projection can be formed on the printing medium.

The printing medium to which the coating liquid is transferred is not particularly limited, and is conventionally known, such as a glass plate, a metal foil, a metal plate, a plastic plate, a plastic sheet, a knitted fabric, Nonwoven fabric, paper and the like can be mentioned. Among them, a glass plate, a metal foil, and a metal plate are preferably used because the transferred coating liquid is not easily absorbed.

Next, examples will be described together with comparative examples.

[0029]

Examples 1 to 10 and Comparative Examples 1 to 11 [Preparation of resin relief plate] First, a glass plate having a thickness of 10 mm was prepared. On this, a negative film is placed, and further on the negative film,
A liquid photocurable resin (APR, manufactured by Asahi Kasei Corporation) was applied using a knife coater so as to have a constant thickness. Thereafter, a base film was placed on the surface of the liquid photocurable resin. Then, after performing light irradiation through the base film, and then performing light irradiation through the negative film to form a printing convex portion, a large number of fine protrusions on the printing convex portion, A groove provided by the minute projection was formed. After the uncured resin is washed and removed, it is dried, and further exposed by light irradiation (post-exposure).
By performing the above, a resin letterpress main body was produced.

The negative film used in the production of the resin relief printing plate was produced by using an image setter for film exposure which is also used in a general printing machine and the like. A pattern which can be formed so as to have the distribution density of the protrusions and the area ratio of the fine protrusions was used.

Next, a pressure-sensitive adhesive with release paper (polyacrylate adhesive, adhesive thickness 0.0) is provided on the surface of the resin relief printing plate main body obtained by the above-mentioned method opposite to the surface on which the printing convex portions are formed.
3 mm), an aluminum plate having a thickness of 0.15 μm was attached. All these steps were performed at a high room temperature of about 50 ° C. to produce a resin relief printing plate.

[0032]

[Table 1]

A thin film was formed by a conventional method using each of the thus obtained resin relief printing plates. That is, as shown in FIG. 4, a printing roll (printing plate cylinder) 11 having the resin relief printing plate 10 mounted on its surface is prepared, and a printing substrate (glass substrate) 13 is placed on a printing stage (platen) 12. Was placed. The nip pressure at the time of performing pattern printing, that is, the distance between the ink roll 14 and the printing roll 11 is 0.1 mm.
(Indentation amount), and the distance between the printing roll 11 and the printing medium 13 was 0.10 mm. The ink roll 14 and the printing roll 11 both maintain smoothness within ± 0.003 mm, and the surface of the printing material 13 has a smoothness within ± 0.050 mm. In FIG. 4, reference numeral 15 denotes an ink supply device, and reference numeral 16 denotes a doctor for scraping excess ink on the ink roll 14.

Under the above conditions, the coating liquid held in the resin relief printing plate 10 was transferred onto the glass substrate 13. Next, the coating liquid transferred onto the glass substrate 13 was heated at 500 ° C.
By firing in an oxidation-reduction atmosphere for × 30 minutes, a polyimide resin thin film layer was formed.

The thickness of the edge of the central region and the peripheral region of the thin film thus obtained was measured using a surface roughness meter (Profiler P-1) manufactured by Tencor Japan. The results are shown in Table 2 below and evaluated. In the evaluation, focusing on the edge thickness of the peripheral region of the thin film layer, ◎ indicates that a remarkable effect was observed in reducing the marginal phenomenon, ○ indicates that some improvement was observed, and × indicates no effect. Notated as not seen.

[0036]

[Table 2]

From the results shown in Table 2 above, all of the products of the examples were formed such that the film thickness at the end of the peripheral region of the thin film was less than or equal to the film thickness in the central region of the thin film. there were. In particular, the ratio [(Y) / (X)] of the distribution density (Y) of the fine protrusions in the peripheral region of the printing protrusion to the distribution density (X) of the fine protrusions in the central region of the printing protrusion is 1 0.3 to 2.3
Those that were within were particularly excellent in evaluation. On the other hand, in all of the comparative examples, the film thickness at the end of the peripheral region of the thin film was larger than the film thickness at the central region of the thin film.

[0038]

As described above, according to the present invention, the central region of the printing convex portion of the resin relief printing plate has adjacent minute projections formed at equal intervals, and the peripheral region of the printing convex portion has
This is a resin relief plate for forming a thin film in which the distribution density of the fine projections is higher than that of the central area, and the occupation area ratio of the fine projections gradually increases toward the end in the peripheral area. For this reason, in the thin film formed using this resin relief printing plate, the occurrence of the marginal phenomenon is suppressed, and a film having a uniform film thickness can be obtained.

Then, the ratio [(Y) / (X)] of the distribution density (Y) of the fine protrusions in the peripheral region of the printing protrusion and the distribution density (X) of the fine protrusions in the central region of the printing protrusion is calculated. When the specific range is set, the occurrence of the marginal phenomenon can be further suppressed, and an alignment film having a uniform film thickness can be formed.

Further, the minute projections are formed in a truncated cone or a columnar shape, and the diameter of the minute projections in the peripheral area of the printing projection is smaller than the diameter of the minute projection in the central area of the printing projection.
When the ratio is set to be a specific ratio to each of the diameter of the minute protrusion near the central region and the diameter of the minute protrusion near the end of the peripheral region, the generation of the marginal phenomenon is further suppressed, and the uniform film is formed. A thick alignment film can be formed.

[Brief description of the drawings]

FIG. 1A is a plan view schematically showing an example of a resin relief plate for forming a thin film according to the present invention, and FIG. 1B is a side view thereof.

FIG. 2 is a plan view schematically showing a part of the resin relief plate for forming a thin film of the present invention.

FIG. 3 is a cross-sectional view schematically showing a part of the resin relief plate for forming a thin film of the present invention.

FIG. 4 is a perspective view showing a manufacturing process of forming a thin film using a resin relief printing plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin relief plate 2 Printing convex part 3 Micro projection 4 Groove part X central area Y peripheral area

Continued on the front page F-term (reference) 2H096 AA02 AA04 BA01 CA20 2H114 AA01 AA14 AA23 AA28 BA02 DA04 DA52 DA73 EA04 GA34

Claims (3)

[Claims] 1. A resin relief plate for forming a thin film, which is used for transferring a coating liquid applied to a printing projection onto a printing medium and printing the printing liquid, wherein a large number of fine projections are distributed on the entire surface of the printing projection. By being formed, a groove portion for holding the coating liquid is formed between adjacent fine protrusions, and a central region of the printing convex portion has adjacent fine protrusions formed at equal intervals. The peripheral region of the printing protrusion is formed such that the distribution density of the fine protrusions is higher than that of the central region, and the occupation area ratio of the fine protrusions gradually increases toward the end in the peripheral region. A resin relief printing plate for forming a thin film. 2. The ratio [(Y) / (X)] between the distribution density (Y) of the fine protrusions in the peripheral region of the printing protrusion and the distribution density (X) of the fine protrusions in the central region of the printing protrusion. But 1.2 to 2.5
The resin relief printing plate for forming a thin film according to claim 1, wherein: 3. The small projections are formed in a truncated cone or a columnar shape, and the diameter of the small projections in the peripheral area of the printing projection is smaller than the diameter of the small projection in the center area of the printing projection. 0.3 × 1.5
The projection diameter is set to be 1.5 times or more and less than 3.0 times in the diameter of the minute projections on the end side of the peripheral region.
Or the resin relief printing plate for forming a thin film according to 2.