JP2015009183A - Line formation method using inkjet method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line formation method capable of providing a thickness-uniform line, by providing a value thick in a thickness of a line, that is, higher than usual (a thickness of a line/a width of the line), even in a fine line, when forming a pattern of an insulation coating film on a substrate by an inkjet method.SOLUTION: The line formation method is provided for forming a line by coating by wet-on-wet coating an activation energy line curable resin composition on the substrate by the inkjet method of using a piezo type inkjet device. The line formation method is provided for wet-on-wet coating by moving by a shorter distance than an impact diameter in the line formation direction for (n+1) time coating to the impact diameter of the activation energy line curable resin composition coated at a predetermined impact pitch in the (n)th time.

Description

  The present invention relates to a line forming method for forming a line by discharging an active energy ray-curable resin composition onto a substrate using an inkjet method.

  In forming an insulating coating having a desired pattern on a substrate, for example, a printed wiring board, in recent years, a pattern may be produced by forming an insulating coating line using an inkjet method. For example, when a screen printing method is used for forming the line of the insulating coating, the preliminary drying process, the photosensitive process, the developing process of the coating film, the post-cure process, and the work after the application of the photocurable resin composition become complicated. . On the other hand, when the ink jet method is used, lines can be formed if the ink is exposed to light after being discharged, so that the operation is simpler than the screen printing method. Therefore, when the ink jet method is used, the manufacturing cost of the patterned insulating coating can be greatly reduced.

  However, in order to use the ink jet method, use an ink that has a lower viscosity than the photocurable resin composition used in the screen printing method and that can prevent bleeding during the curing process. There is a need to. Therefore, Patent Document 1 proposes a curable resin composition having the above characteristics and suitable for the ink jet method.

  As in Patent Document 1, by using a curable resin composition suitable for the inkjet method, a uniform and thin insulating film can be formed on a printed wiring board in a desired pattern. On the other hand, it may be required to form a uniform and thick insulating coating pattern on a printed wiring board using an inkjet method.

  In Patent Document 1, an insulating film having a relatively uniform thickness can be formed by an ink jet method. However, in order to reduce the thickness of the insulating film as much as possible, as shown in FIGS. Is once. That is, since the line 51 is formed from the droplet 5 discharged by one coating on the substrate s, the thickness of the line 51 is limited, and there is no proposal for adjusting the thickness of the line 51.

JP 2010-229220 A

  In view of the above circumstances, an object of the present invention is to form an insulating film pattern on a substrate by an inkjet method, even if it is fine, a thick line, that is, a higher aspect ratio (ie, a line than conventional). It is an object of the present invention to provide a line forming method capable of obtaining a line having a value of (thickness / line width) and having a uniform thickness.

  An aspect of the present invention is a line forming method in which an active energy ray-curable resin composition is overcoated on a substrate to form a line by an ink jet method using a piezo type ink jet device, and is predetermined at the nth time. The n + 1th coating is overcoated by moving a distance shorter than the landing diameter in the formation direction of the line with respect to the landing diameter of the active energy ray-curable resin composition applied at a landing pitch of The line forming method is characterized by the above.

  In this embodiment, the active energy ray-curable resin composition coated at the nth time is parallel to the line forming direction by a distance less than the landing diameter d of the nth droplet from the landing position of the droplet at the nth time. The landing position of the droplet is moved, and the active energy ray-curable resin composition is applied n + 1 times. Since the shifted distance is less than the landing diameter d of the n-th droplet, the droplet landed on the (n + 1) th time and the droplet landed on the n-th time are in a state in which a part of the liquid droplet is overcoated with each other. Become.

  In this embodiment, the same active energy ray-curable resin composition is used for the n-th coating and the (n + 1) -th coating.

  In addition, said n means an integer greater than or equal to 1. Moreover, the landing pitch p is an inkjet discharge pitch, and means the distance between the centers of droplets of the active energy ray-curable resin composition that are adjacent to each other and land on the substrate.

  An aspect of the present invention is the line forming method, wherein the distance is in a range of 40% to 60% of the landing diameter. In this aspect, with respect to the position of the droplet landed at the nth time, the landing position of the liquid droplet is equivalent to a distance corresponding to 40% to 60% of the landing diameter d of the nth droplet in the line forming direction. The n + 1th overcoating is performed by shifting.

  An aspect of the present invention is a line forming method characterized in that the coating and the curing with an active energy ray are performed in parallel. The above “parallel” means that the droplet of the active energy ray-curable resin composition applied for the nth time is changed to an active energy ray (for example, ultraviolet rays) before the nth time application on the substrate is completed. Means to cure.

  An aspect of the present invention is the line forming method, wherein the number of times of overcoating is one or more.

  An aspect of the present invention is the line forming method, wherein the landing pitch p is larger than the landing diameter d.

  An aspect of the present invention is the line forming method, wherein the thickness / width of the line is 0.1 or more.

  An aspect of the present invention is the line forming method, wherein the substrate is a printed wiring board.

  According to the aspect of the present invention, the landing positions of the droplets of the active energy ray-curable resin composition applied n + 1 times are the landing positions of the droplets of the active energy ray-curable resin composition applied n times. From the above, it is possible to form fine and thick lines by overcoating in a state shifted in the line formation direction by a distance less than the landing diameter d of the nth droplet, and further dividing into the formed lines And the occurrence of unevenness can be prevented. Thus, according to the aspect of the present invention, it is possible to prevent the line from being divided or uneven, and thus it is possible to form a thick pattern having an excellent line shape.

  According to the aspect of the present invention, it is possible to cause division and unevenness in the formed line by performing overcoating while being shifted in the line forming direction by a distance of 40% to 60% of the landing diameter d. It can be surely prevented and a more excellent line shape can be obtained.

  According to the aspect of the present invention, droplets of the active energy ray-curable resin composition applied n times (or n + 1 times) are collected by performing coating and curing with active energy rays in parallel. It is possible to reliably prevent formation of wetting and spreading of droplets. As a result, the line width can be reliably prevented from increasing.

  According to the aspect of the present invention, since the landing pitch is larger than the landing diameter, it is possible to surely prevent the liquid droplets that have landed earlier from being absorbed and the line width from being increased.

(A) The figure is sectional drawing explaining the outline | summary of the line formed with the line formation method of this invention, (b) The figure is a top view explaining the outline | summary of the line formed with the line formation method of this invention, (C) The figure is a front view explaining the outline | summary of the line formed with the line formation method of this invention. It is explanatory drawing which shows the outline | summary of the line formation method of this invention. (A) The figure is sectional drawing explaining the outline | summary of the line formed with the conventional line formation method, The same (b) figure is a top view explaining the outline | summary of the line formed with the conventional line formation method, (c) FIG. 6 is a front view for explaining an outline of a line formed by a conventional line forming method. (A) is a cross-sectional view for explaining the outline of a line formed by an overcoat line forming method that is not the present invention, and (b) is an illustration of a line formed by an overcoat line forming method that is not the present invention. The top view explaining an outline and the figure (c) figure are the front views explaining the outline of the line formed with the overpainting line formation method which is not the present invention.

  Next, embodiments of the line forming method of the present invention will be described with reference to the drawings. As shown in FIG. 1, a first piezoelectric device having a circular shape in plan view, which is an active energy ray-curable resin composition, is formed on a substrate s (here, a printed wiring board) using a piezo-type ink jet device (not shown). The first droplet 1 is ejected in a straight line and applied for the first time, and the first droplet 1 is cured by an active energy ray in parallel with the coating, and thus the cured first droplet 1 is formed. A linear first line 11 is produced. In the above embodiment, the landing pitch p1 of the first droplet 1 is larger than the landing diameter d1 of the first droplet 1, and specifically, the landing pitch p1 is d1 <p1 <d1 × 1.1. It has become.

  After producing the first line 11, the second line 21 is overcoated on the first line 11 using the same piezo ink jet apparatus. In the second line 21, the same active energy ray-curable resin composition as that in the first line 11 is used. Similar to the first line 11, the second line 21 also discharges the second droplet 2 having a circular shape in a plan view, which is an active energy ray-curable resin composition, in a straight line to apply the second coating. In parallel with this coating, the second droplet 2 is cured by active energy rays. In FIG. 1, since the landing diameter d1 of the first droplet 1 and the landing diameter d2 of the second droplet 2 are the same, the landing pitch p2 of the second droplet 2 is the landing pitch of the first droplet 1. The same as p1.

  In the second coating, the landing positions of the second droplets 2 are moved in the line forming direction by a distance shorter than the landing diameter d1 of the first droplets 1 discharged in the first coating. Apply paint. In FIG. 1, a line is formed by a distance corresponding to half of the landing diameter d1 of the first droplet 1 discharged by the first coating at the landing position of the second droplet 2 discharged by the second coating. It is moved in the direction and the second coating is performed.

  Similarly, after producing the second line 21, the third line 31 is overcoated on the second line 21 using a piezo ink jet apparatus. In the third line 31 as well, the same active energy ray-curable resin composition as that in the first line 11 and the second line 21 is used. Similarly to the first line 11 and the second line 21, the third line 31 also discharges the third droplet 3 having a circular shape in plan view, which is an active energy ray-curable resin composition, in a straight line. Then, the third coating is performed, and the third droplet 3 is cured by active energy rays in parallel with the coating. In FIG. 1, since the landing diameter d3 of the third droplet 3 is the same as the landing diameter d1 of the first droplet 1 and the landing diameter d2 of the second droplet 2, the landing pitch of the third droplet 3 is the same. p3 is the same as the landing pitch p1 of the first droplet 1 and the landing pitch p2 of the second droplet 2.

  Even in the third coating, the coating is performed by moving the landing position of the third droplet 3 in a line forming direction at a distance shorter than the landing diameter d2 of the second droplet 2 discharged in the second coating. do. In FIG. 1, a line is formed by a distance corresponding to half of the landing diameter d2 of the second droplet 2 ejected by the second coating at the landing position of the third droplet 3 ejected by the third coating. It is moved in the direction and the third coating is performed. In this way, the numerical value of thickness / width (hereinafter, sometimes referred to as “aspect ratio”) may be obtained by sequentially moving the droplet landing position in the line forming direction and performing repeated coating for each coating. A high linear line R, that is, a pattern with a high aspect ratio can be formed on the substrate.

  As shown in FIG. 1 (c), in the embodiment of the line forming method of the present invention, a line with a higher aspect ratio can be formed compared to FIG. 3 (c), which is a conventional coating method without overcoating. Therefore, a fine and thick line can be obtained. Further, in the embodiment of the line forming method of the present invention, FIG. 4 is obtained by repeatedly applying the landing positions of the droplets of the active energy ray-curable resin composition without shifting the n-th coating and the (n + 1) -th coating. Compared with (a) (three times of coating in FIG. 4), it is possible to prevent the lines from being divided or uneven, and thus a pattern having an excellent line shape can be formed.

  In FIG. 4, as in the above embodiment, the droplets 12 of the active energy ray-curable resin composition are ejected to perform the first coating, and the droplets of the active energy rays are applied in parallel with the coating. 12 is cured, and a first line 13 composed of the cured droplets 12 is produced. The landing pitch of the droplets 12 is substantially the same as the landing diameter of the droplets 12. However, in FIG. 4, the second line 15 in which the coated droplet 14 is cured at the same landing position as the droplet 12 on the first line 13 by the same method as the first line 13. The third line 17 is produced on the second line 15 at the same landing position as the liquid droplets 12 and 14 by curing the coated liquid droplet 16. A pattern of a line R ′ is formed from the first line 13, the second line 15, and the third line 17.

  In the above embodiment example, each of the first line 11, the second line 21, and the third line 31 has a droplet landing pitch of more than 1.0 times the droplet landing diameter to 1.1. The landing pitch is not particularly limited as long as the landing pitch is larger than the landing diameter. For example, the landing pitch is more than 1.0 times the landing diameter from the viewpoint of coating property and printability. 3.0 times is preferable, and more than 1.0 times to 2.0 times is particularly preferable from the viewpoint of line formation. Furthermore, since the landing pitch p1 of the first line 11, the landing pitch p2 of the second line 21, and the landing pitch p3 of the third line 31 are the same in the landing diameters d1, d2, and d3, However, the landing pitches p1, p2, and p3 may be changed according to the difference in the landing diameters d1, d2, and d3 of the respective lines.

  Further, in the above embodiment, the droplet landing position is moved in the line formation direction by a distance corresponding to half of the droplet landing diameter d (that is, 50% of the landing diameter d), and the next overlap is performed. Although the coating has been performed, the distance is not particularly limited as long as the distance is less than the landing diameter d. For example, the distance of the movement is preferably 20% to 80% of the landing diameter d from the viewpoint of obtaining a high aspect ratio while surely preventing the occurrence of fragmentation or unevenness in the line. From the point, 40% to 60% is particularly preferable.

  In the above embodiment example, the number of times of coating was 3, that is, the number of times of overcoating was 2. However, the number of times of overcoating can be appropriately selected as necessary, and may be 1 time or 3 times or more. But you can. In the above embodiment, the line R is linear, but the line shape drawn on the substrate is not particularly limited, and may be drawn in other shapes such as a curved shape.

  Next, the line forming method will be described in more detail with reference to FIG. 2 which is another embodiment of the present invention. In addition, FIG. 2 is the figure which paid its attention to only a part of coating range about the board | substrate which coats and coats an active energy ray-curable resin composition. The thin line droplets are those before photocuring, and the thick lines are those after photocuring.

  As shown in FIG. 2, in another embodiment, the landing pitch p1 of the first droplet 1 discharged in the first coating is further larger than the landing diameter d1 of the first droplet 1. That is, the landing pitch p1 is different from the above embodiment in that d1 × 2 <p1 and the number of coatings is four.

  In other embodiments, the first coating is performed on the substrate s (step (a) in FIG. 2), but before the first coating on the entire surface of the substrate s is completed, that is, the first coating is performed. During the construction process, the first droplet 1 coated in the first coating process is sequentially cured by active energy rays (process (b) in FIG. 2), and the first line 11 is produced. Accordingly, it is possible to reliably prevent the first droplets 1 from gathering and forming the wetting and spreading of the first droplets 1, thereby reliably preventing the width of the first line 11 from being increased. it can.

  After all the first coating and curing are completed on the entire surface of the substrate s, the second coating is performed on the substrate s (step (c) in FIG. 2), as in the first coating. Before the second coating is completed, the second droplets 2 coated in the second coating step are sequentially cured with active energy rays (step (d) in FIG. 2). The second line 21 is produced. Similar to the above-described embodiment, the second liquid droplet 2 is shifted from the first liquid droplet 1 in a state where the second liquid droplet 2 is shifted in the line formation direction by a distance less than the landing diameter d1 of the first liquid droplet 1. Overcoat with the same impact diameter and impact pitch.

  After completing the second coating and curing on the entire surface of the substrate s, the third coating is performed on the substrate s in the same manner as the second coating (step (e) in FIG. 2). s Before the third coating on the entire surface is completed, the third droplet 3 coated in the third coating step is sequentially cured with active energy rays ((f) in FIG. 2). Step), the third line 31 is produced.

  Thereafter, in the same manner, while applying the fourth time (step (g) in FIG. 2), the coated fourth droplet 4 is cured with active energy rays (step (h) in FIG. 2). A fourth line 41 is produced. In FIG. 2, since the landing pitch p1 of the first droplet 1 discharged in the first coating is larger than twice the landing diameter d1 of the first droplet 1, the line is not applied in the third coating. The surface of the substrate s was still exposed between the first droplet 1 and the third droplet 3 adjacent to each other in the formation direction, but the adjacent fourth droplet was formed by the fourth coating. The surface of the substrate s is not exposed between the four, and the line division is eliminated.

  Further, if necessary, a thicker line may be formed by performing coating and curing for the fifth and subsequent times in the same manner as described above.

  In the above-described other embodiment examples, any of the second line 21, the third line 31, the fourth line 41, and a line that is further coated on the fourth line 41 as necessary. Since the width can be prevented from widening, it is possible to prevent the width of the entire line R obtained by overcoating in a state where the landing pitch is larger than the landing diameter from being widened.

  The active energy ray-curable resin composition used in the present invention has basic characteristics that can be used in a piezo ink jet device, that is, has a viscosity at 25 ° C. in the range of 5 to 25 mPa · s, and has an active energy. It is not particularly limited as long as it is cured by irradiation with a line (for example, ultraviolet rays), for example, an active energy containing a photosensitive resin having one or more photosensitive unsaturated double bonds and a photopolymerization initiator. A linear curable resin composition can be mentioned.

  Next, examples of the present invention will be described. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

  A piezo-type inkjet device in which “KM1024SHB” (6pL, 512 nozzles × 2 rows) manufactured by Konica Minolta Co., Ltd. was attached as an inkjet head to an inkjet device (“MJP2013F1” manufactured by Microcraft Co., Ltd.) was used.

  Three types of ink A, ink B, and ink C were used as the active energy ray-curable resin composition. The respective inks were prepared by blending the components shown in Table 1 below at the blending ratios shown in Table 1 and mixing and dispersing them at room temperature using a planetary mixer. In addition, the number of the mixture ratio in the following Table 1 shows a mass part. In addition, the additive in Table 1 is blended for leveling properties.

Test piece manufacturing process The above-mentioned piezo-type ink jet device is placed on a substrate (without surface treatment of the substrate) of glass (Matsunami Glass Industry Co., Ltd., “MICRO SLIDE GLASS S9213”) having a size of 76 × 52 mm and a thickness of 1.2 mm. The ink, which is an active energy ray-curable resin composition prepared as described above, was applied in a straight line, and in addition to the coating, ultraviolet rays (a lamp having a distribution mainly at wavelengths of 240 to 420 nm) were used. ), The coated active energy ray-curable resin composition was cured to form a line, and test pieces of Examples 1 to 5 and Comparative Examples 1 to 5 were produced. A metal halide lamp (manufactured by Micro Craft, “Sub Zero 85 light intensity on-head UV D bulb”) was used for ultraviolet irradiation.

  In preparation of the test piece, in Example 1, the landing diameter of the liquid ink is 70 ± 10 μm in each coating time, the landing pitch is 90 μm in each coating time, and in the second and subsequent coatings in the line forming direction. The shift distance of the landing position was set to 64% of the landing diameter of the previous coating for each coating time. In Example 2, the landing diameter is 70 ± 10 μm for each coating time, the landing pitch is 90 μm for each coating time, and the distance of shifting the landing position in the line forming direction in the second and subsequent coatings is each coating time. Both times were 43% of the impact diameter of the previous coating. In Example 3, the landing diameter is 70 ± 10 μm for each coating time, the landing pitch is 90 μm for each coating time, and the distance of shifting the landing position in the line forming direction in the second and subsequent coatings is each coating time. Both times were 21% of the impact diameter of the previous coating. In Example 4, the landing diameter is 70 ± 10 μm for each coating time, the landing pitch is 90 μm for each coating time, and the distance of shifting the landing position in the line forming direction in the second and subsequent coatings is the coating distance. Both times were 43% of the impact diameter of the previous coating. In Example 5, the landing diameter is 70 ± 10 μm for each coating time, the landing pitch is 90 μm for each coating time, and the distance of shifting the landing position in the line forming direction in the second and subsequent coatings is the coating distance. Both times were 43% of the impact diameter of the previous coating.

  In preparing the test piece, in Comparative Example 1, the landing diameter of the liquid ink was 70 ± 10 μm, and the landing pitch was 90 μm. In Comparative Example 2, the landing diameter was 70 ± 10 μm for each coating time, and the landing pitch was 90 μm for each coating time. In Comparative Example 3, the landing diameter was 70 ± 10 μm for each coating time, and the landing pitch was 90 μm for each coating time. In Comparative Example 4, the landing diameter was 70 ± 10 μm for each coating time, and the landing pitch was 90 μm for each coating time. In Comparative Example 5, the landing diameter was 70 ± 10 μm for each coating time, the landing pitch was 35 μm for each coating time, and the shift distance of the landing position in the line forming direction in the second coating was the previous time It was 43% of the impact diameter of the coating.

Evaluation (1) Line Shape The line shape of the substrate was observed with a microscope (OLYMPUS, “STM-UM”) at × 100 magnification, and evaluated as follows.
“◯”: The coating film is formed in a line shape, and no division is observed in the line.
“X”: The line is broken in some places, and the substrate surface is visible.

(2) Smoothness of line surface A test piece was prepared in the same manner as described above except that a glass substrate (25 mm x 75 mm, thickness 1.2 mm) was used. The surface smoothness after curing of each applied ink was evaluated using a surface roughness meter (manufactured by Tokyo Seimitsu / Meijin Koki Co., Ltd., model “Surfcom 570A / SAS-2010”).
“O”: arithmetic average roughness (Ra) <2 μm
“×”: arithmetic average roughness (Ra) ≧ 2 μm

(3) Aspect ratio The film thickness and line width of the line were measured with the above microscope (× 100 times) and calculated from the film thickness / line width of the line.

  Table 2 below shows the ink (active energy ray-curable resin composition) used in Examples 1 to 5 and Comparative Examples 1 to 5, ink characteristics, ink overcoating method, and evaluation results.

  In addition, the viscosity of each ink described in Table 2 is a viscosity at room temperature (25 ° C.), and was measured using an SV type (tuning fork type vibration type) viscometer (model: SV-10).

  As shown in Table 2, in each of the examples that were overcoated by shifting 21% to 64% of the landing diameter, no breakage occurred in the line regardless of the ink, and a good line shape was obtained. . Furthermore, in the examples, Ra <2 μm, and the occurrence of irregularities on the line surface was suppressed, and a line having excellent line surface smoothness, that is, a uniform thickness could be formed. Furthermore, in the examples, an aspect ratio of 0.09 or more, that is, a fine and thick line was obtained with a line width of 70 to 80 μm. In particular, in Examples 2, 4, and 5 in which the overcoating was performed twice, the aspect ratio was 0.1, and in Example 3 in which the overcoating was performed five times, the aspect ratio was 0.15, while maintaining a fine line width, A thicker line could be formed.

  On the other hand, in Comparative Examples 3 and 4 in which the landing positions corresponding to FIG. 4 were overlaid without shifting, fine lines and aspect ratios equivalent to those in each example could be obtained, but the lines were divided. Thus, a good line shape could not be obtained. In Comparative Examples 3 and 4, since the breakage occurred in the line, the smoothness of the line surface was not obtained. In Comparative Example 1 with zero overcoating corresponding to FIG. 3 and Comparative Example 2 with one overcoating, thick lines with a high aspect ratio, that is, aspect ratios of 0.04 and 0.06, respectively, are high in aspect ratio. A line could not be formed, and a good line shape and smoothness of the line surface could not be obtained. Further, in Comparative Example 5 in which the landing pitch was about half of the landing diameter, even if the coating was shifted by 43% of the landing diameter, a good line shape was not obtained, and the smoothness of the line surface was not obtained.

  Since the present invention can obtain a fine, thick, and evenly uniform line, it has a high utility value in the field of, for example, a solder resist film of a printed wiring board and a fine pattern for a touch panel.

DESCRIPTION OF SYMBOLS 1 1st droplet 2 2nd droplet 3 3rd droplet 4 4th droplet 11 1st line 21 2nd line 31 3rd line 41 4th line

Claims (7)

A line forming method in which an active energy ray-curable resin composition is repeatedly coated on a substrate to form a line by an inkjet method using a piezo-type inkjet device,
With respect to the landing diameter of the active energy ray-curable resin composition applied at a predetermined landing pitch for the nth time, the n + 1th coating is moved by a distance shorter than the landing diameter in the line forming direction. A line forming method characterized in that the overcoating is performed.   The line forming method according to claim 1, wherein the distance is in a range of 40% to 60% of the landing diameter.   The line forming method according to claim 1, wherein the coating and the curing with an active energy ray are performed in parallel.   The line forming method according to claim 1, wherein the number of times of overcoating is one or more.   The line forming method according to claim 1, wherein the landing pitch is larger than the landing diameter.   6. The line forming method according to claim 1, wherein the thickness / width of the line is 0.1 or more.   The line forming method according to claim 1, wherein the substrate is a printed wiring board.