JP6938221B2 - How to form a print pattern - Google Patents

Description

The present invention relates to a method for forming a print pattern.

In recent years, printing technology has come to be used in various fields, and its versatility is extremely high. In particular, recently, it is often used for forming fine lines, and it has become possible to form a complicated print pattern.

Examples of such a printing pattern include a pattern in which one thin line is bent at a predetermined angle, a pattern in which two or more thin lines intersect at a predetermined angle, and the like. Bent portions and intersections of such thin lines have a common structural feature that they include bent portions when focusing only on their shapes.

For forming such a printing pattern, a method using an intaglio as a printing plate, such as an offset printing method and a gravure offset printing method, is widely used. In these methods, the grooves in the printing plate (intaglio) are filled with ink, and the ink is transferred to form a printing pattern.

In recent years, a printing pattern forming method using an intaglio as a printing plate has also been used for forming a conductive pattern, and is used, for example, for manufacturing a wiring board having conductive thin wires (wiring). May be done.
Wiring boards are useful as members for touch panels, electromagnetic wave shields, and the like in various electronic devices, and in particular, demand for touch panels is rapidly increasing in various display elements such as information and communication devices such as mobile phones. The wiring board is configured by providing fine metal wires such as silver and copper as electrodes on a transparent substrate, and the fine metal wires form, for example, a mesh.

If the above-mentioned printing pattern forming method is used for manufacturing such a wiring board, the wiring board can be manufactured inexpensively and easily, which is extremely useful. On the other hand, a wiring board in which conductive thin wires are formed by using a gravure offset printing method is disclosed (see Patent Document 1).

International Publication No. 2015/1117115

However, when forming a printing pattern using such a printing plate (intaglio), the width of the thin wire is larger than the width of the groove in the intaglio at the bent portion of the thin wire in the direction parallel to the surface of the substrate. There is a problem that it ends up. It is presumed that this is because the shape of the ink immediately after printing collapses (sags) before the ink dries. Normally, the narrower the width of the thin line, the more the bent portion The smaller the angle, the more noticeable. As described above, there is a problem that it is difficult to faithfully realize the target shape in the bent portion of the thin wire formed by using the intaglio.

Further, in this way, if the width of the thin line is expanded beyond the target width at the bent portion of the thin line, the thin line having an unintended line width is not only formed but also larger. It can also cause problems. For example, in the touch panel as described above, a wiring board having a thin metal wire as an electrode on a transparent substrate is used, but as described above, when the width of the thin metal wire is expanded at the bent portion of the thin metal wire. A thin metal wire, which is usually designed so as not to be visually recognized, becomes easily visible.

On the other hand, it is not clear whether or not the method of forming the conductive thin wire disclosed in Patent Document 1 can suppress the occurrence of such a defect.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for forming a print pattern including a thin line having a bent portion, which can suppress an expansion of the width of the thin line at the bent portion. do.

In order to solve the above problems, the present invention is a method for forming a printing pattern using an intaglio plate as a printing plate, wherein the printing plate has a groove for filling an ink on the surface thereof, and the groove is the groove. Provided is a method for forming a printing pattern, which has a bent portion that bends in a direction parallel to the surface of the printing plate and has a constriction on a side where the groove forms an angle of less than 180 ° of the bent portion.

According to the present invention, as a method for forming a print pattern including a thin line having a bent portion, a method capable of suppressing an expansion of the width of the thin line at the bent portion is provided.

It is a top view which shows typically the example of the printing plate used in this invention by enlarging the region where the groove is formed. FIG. 5 is an enlarged plan view showing an enlarged view of a bent portion of the groove shown in FIG. 1. It is a top view which shows the other example of the printing plate used in this invention by enlarging the region where the groove is formed. FIG. 5 is a plan view schematically showing an enlarged region where a groove is formed for still another example of the printing plate used in the present invention. FIG. 5 is a plan view schematically showing an enlarged region where a groove is formed for still another example of the printing plate used in the present invention. It is an enlarged plan view which shows an example of the printing pattern formed by using the printing plate shown in FIG. 1 or FIG. It is an enlarged plan view which shows an example of the printing pattern formed by using the printing plate shown in FIG. It is an enlarged plan view which shows an example of the printing pattern formed by using the printing plate 3 shown in FIG. It is an enlarged plan view which shows an example of the printing pattern formed by using the conventional printing plate.

<< How to form a print pattern >>
The printing pattern forming method of the present invention is a printing pattern forming method using an intaglio as a printing plate, the printing plate has a groove for filling an ink on the surface thereof, and the groove is the printing. It has a bent portion that bends in a direction parallel to the surface of the plate, and has a constriction on the side where the groove forms an angle of less than 180 ° of the bent portion.
In the present specification, the "bent portion" of the groove in the printing plate means the above-mentioned one unless otherwise specified, and when the surface having the groove of the printing plate is viewed in a plan view from above. In addition, the groove is bent in the surface.

In the present invention, the groove having the bent portion in the printing plate has a constriction on the side forming an angle of less than 180 ° of the bent portion, so that the bent portion of the fine line in the printing pattern corresponding to the bent portion is formed. In, it is possible to suppress the unintended expansion of the width of the thin line. In the present invention, in anticipation of an increase in the width of the thin line at the bent portion of the thin line in the printing pattern during printing, the bent portion of the groove in the printing plate is provided with the above-mentioned constriction to provide the bent portion of the groove. The amount of ink that can be filled in is reduced in advance compared to other parts of the groove. As a result, the amount of ink transferred from the printing plate at the bent portion in the printing pattern is reduced as compared with the normal case where no constriction is provided, so that the shape of the ink immediately after printing is until the ink dries. The effect of collapsing (sagging) in the meantime is reduced, and unintended expansion of the width of the thin line is suppressed.

In the present invention, the "bent portion" means an entire portion having a shape that can be regarded as a bent linear object. For example, the bent portion of one linear object naturally corresponds to the bent portion. In addition to that, for example, when two linear objects having no bent portion intersect, this intersection also includes a shape that can be regarded as a bent linear object. The bent portion of the case also corresponds to the bent portion. Such an intersection can be regarded as a linear one having two bent portions overlapping at these bent portions. At such an intersection, there are four bent portions, two of which are individually linear ones having two bent portions, and the remaining two portions. Can be regarded as having these integrated objects because the two linear objects are overlapped and integrated as described above.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view schematically showing an example of a printing plate used in the present invention in an enlarged region in which a groove is formed.
In addition, in the figure used in the following description, in order to make it easy to understand the features of the present invention, the main part may be enlarged for convenience, and the dimensional ratio and the like of each component are the same as the actual ones. Is not always the case.

The printing plate 1 shown in FIG. 1 has a fine line-shaped groove 9 for filling the surface 1a of the ink to be used for printing, and is an intaglio plate. As shown here, the groove 9 is open on the surface 1a when the surface 1a of the printing plate 1 is viewed in a plan view from above, and has a bent portion 90 in the surface 1a. That is, the groove 9 has a bent portion 90 that bends in a direction parallel to the surface 1a of the printing plate 1.
The groove 9 is bent at an angle θ (0 ° <θ <180 °) at the bent portion 90.

Further, the groove 9 has a constriction 91 on the side of the bent portion 90 at an angle (θ) of less than 180 °.
When the constriction 91 is viewed in a plan view as described above, the constriction 91 has an angle (θ) of less than 180 ° of the bent portion 90 from the side forming the opposite side (360 ° −θ) inside the groove 9. A polyhedral projecting portion is formed and configured so as not to block the groove 9 toward the forming side). In the present specification, the "neck" of the groove may be referred to as a "protruding portion" in this way.

FIG. 2 is an enlarged plan view showing an enlarged view of the bent portion 90 included in the groove 9.
In the drawings after FIG. 2, the same components as those shown in the already explained figures are designated by the same reference numerals as in the case of the already explained figures, and detailed description thereof will be omitted.
As shown in FIG. 2, the length of the protrusion 91 is L ₁ and the width is L ₂ .
Here, the "length of the protruding portion 91" means that, as shown in FIG. 2, the groove 9 has a predetermined angle on the side where the protruding portion 91 is not formed and the bent portion 90 forms an angle θ. It means the distance from the bent portion (corner portion) of the groove 9 to the tip of the protruding portion 91, which is specified when it is assumed that the groove 9 is bent (the corresponding portion is indicated by a broken line in FIG. 2). do. At this time, assuming that the groove 9 is formed so as to extend linearly from a portion other than the bent portion 90 toward the bent portion 90, the bent portion (corner portion) of the groove 9 is specified.

The polyhedral projecting portion can be a prismatic shape such as a square columnar shape. However, the shape of the protruding portion is not limited to this.

The angle θ is not particularly limited as long as the condition of 0 ° <θ <180 ° is satisfied, and may be less than 90 ° (in other words, an acute angle) or 90 ° (in other words, a right angle). However, it may be larger than 90 ° (in other words, it may be an acute angle).
Generally, the smaller the angle θ, the more remarkable the effect of the present invention can be obtained.

The number of grooves 9 in the printing plate 1 may be only one or two or more.
Further, the printing plate 1 may have one or two or more grooves other than the groove 9, and the groove other than the groove 9 may or may not have a constriction. good.
In the printing plate 1, the position (arrangement position) where the groove 9 and the other grooves are provided can be arbitrarily set according to the purpose and is not particularly limited.

_{The width W 1} of the opening on the surface 1a of the printing plate 1 other than the bent portion of the groove 9 is not particularly limited and can be arbitrarily selected depending on the intended purpose.
The width W ₁ is preferably 1 to 20 μm, more preferably 2 to 10 μm, and particularly preferably 3 to 5 μm. When the width W ₁ is equal to or larger than the lower limit value, the print pattern (thin line) can be formed more stably without being accompanied by various shape abnormalities such as disconnection. When the width W ₁ is equal to or less than the upper limit value, a higher effect of suppressing an unintended expansion of the width of the thin line at the bent portion of the thin line during printing can be obtained.

In the present invention, when the width of the groove opening is not constant in the groove length direction (longitudinal direction) and fluctuates, the term "groove opening width" is particularly excluded. Unless otherwise indicated, it shall mean the width at the widest part of the groove opening.
Further, the "width of the groove" shall mean the "width of the opening of the groove" unless otherwise specified.

The depth of the groove 9 is not particularly limited and can be arbitrarily selected depending on the intended purpose.
The depth of the groove 9 is preferably 0.5 to 10 μm, more preferably 0.8 to 5 μm, and particularly preferably 1.1 to 1 μm. When the depth of the groove 9 is not more than the lower limit value, the print pattern (thin line) can be formed more stably without being accompanied by various shape abnormalities such as disconnection. When the depth of the groove 9 is not more than the upper limit value, a higher effect of suppressing an unintended expansion of the width of the thin line at the bent portion of the thin line during printing can be obtained.

In the present invention, when the depth of the groove is not constant in the width direction of the groove or is not constant in the length direction (longitudinal direction) of the groove, or when the depth varies depending on the portion of the groove, "groove" is used. "Depth" shall mean the depth at the deepest part of the groove, unless otherwise specified.

In the printing plate 1, the length L ₁ and the width L ₂ of the protrusion 91 are preferably adjusted as appropriate according to the width W _{1 of the groove 9.}
Usually, for example, when the width W ₁ is within the above numerical range, the length L ₁ of the protruding portion 91 is preferably 1 to 3 μm, and the width L ₂ of the protruding portion 91 is 0.5 to 2 μm. Is preferable.

In the present invention, _{the value of L 1} × L ₂ / W ₁ is preferably 0.46 μm or less, more preferably 0.44 μm or less, and particularly preferably 0.42 μm or less. By the value is equal to or less than the upper limit, the width W ₁ of the groove, due to the degree of constriction of the groove is too large, the occurrence of abnormal shape in the bending portion of the fine line is further suppressed. Here, the "shape abnormality at the bent portion of the thin wire" means "a clear shape abnormality at the bent portion of the thin wire to the extent that the thin wire cannot fully exert its function", and for example, the disconnection of the thin wire corresponds to it. However, the shape abnormality of the thin wire in which no disconnection is observed is also applicable.

On the other hand, _{the value of L 1} × L ₂ / W ₁ is preferably 0.35 μm or more, more preferably 0.38 μm or more, and may be, for example, 0.4 μm or more. When the value is at least the lower limit value, a higher effect of suppressing an unintended expansion of the width of the thin line can be obtained at the bent portion of the thin line.

In the present invention, _{the value of L 1} × L ₂ / W ₁ is appropriately adjusted so as to be a numerical range determined by arbitrarily combining any of the above lower limit values and any of the upper limit values. can.
For example, _{the value of L 1} × L ₂ / W ₁ can be preferably 0.35 to 0.46 μm, more preferably 0.38 to 0.44, but these numerical ranges are L ₁ × L. of ₂ / _{W 1} is an example of a preferable range.

FIG. 3 is a plan view schematically showing another example of the printing plate used in the present invention by enlarging the region where the groove is formed.
The printing plate 2 shown here is an intaglio plate having fine line-shaped grooves 9A and 9B for filling the surface 2a with ink to be used for printing.
The grooves 9A and 9B are open on the surface 2a when the surface 2a of the printing plate 2 is viewed in a plan view from above.

The grooves 9A and 9B are both similar to the groove 9 shown in FIG. 1, and are bent like the groove 9. Then, in the printing plate 2, the grooves 9A and 9B can be regarded as sharing the bent portion 90 with each other. From a different point of view, in the printing plate 2, it can be considered that two linear grooves intersect.
The grooves 9A and 9B may be the same as or different from each other.

It can be considered that the grooves 9A and 9B each have a bent portion 90 independently, and the grooves 9A and 9B together have two bent portions 90'.
_{That is, the grooves 9A and 9B as a whole have angles θ 1} , θ ₂ , θ ₃ or θ ₄ (0 ° <θ ₁ , θ ₂ , θ ₃ ) at these bent portions (bending portion 90 and bending portion 90'). , Θ ₄ <180 °), and can be regarded as bent.

The number of grooves 9A and 9B in the printing plate 2 may be only one or two or more, respectively.
When the number of grooves 9A and 9B in the printing plate 2 is two or more, it is preferable that the grooves 9A and 9B are provided in a mesh shape.

Further, the grooves 9A and 9B as a whole are constricted on the side forming _{an angle (θ 1} , θ ₂ , θ ₃ , θ ₄ ) of these bent portions (bent portion 90 or bent portion 90') less than 180 °. , Constriction 912, constriction 913 or constriction 914.
More specifically, the groove 9A alone has a constriction 911 on the side of the bent portion 90 at an angle (θ _{1) of less than 180 °.}
Similarly, the groove 9B alone has a constriction 912 on the side of the bent portion 90 at an angle (θ _{2) of less than 180 °.}
The grooves 9A and 9B together have a constriction 913 and a constriction 914 on the side of the bent portion 90'at an angle of less than 180 ° (θ ₃ , θ _4).

The constriction 911, the constriction 912, the constriction 913, and the constriction 914 are also formed in the same manner as in the case of the constriction 91 in the printing plate 1.
More specifically, when the constriction 911 is viewed in a plan view as described above, the constriction 911 is located inside the groove 9A from the side forming _{an angle (θ 1) of less than 180 ° of the bent portion 90 to the opposite side (θ 1).} A polyhedral projecting portion is formed and configured so as not to block the groove 9A toward the side forming an angle of 360 ° −θ _1).
When the constriction 912 is viewed in a plan view as described above, the constriction 912 is located inside the groove 9B _{from the side forming an angle (θ 2} ) of less than 180 ° of the bent portion 90 to the opposite side (360 ° −θ ₂ ). A polyhedral projecting portion is formed and configured so as not to block the groove 9B toward the angled side).
When the constriction 913 is viewed in a plan view as described above, the constriction 913 is formed from the side _{of the bent portion 90'at an angle (θ 3) of less than 180 ° inside the groove in which the grooves 9A and 9B are integrated.} A polyhedral projecting portion is formed and configured so as not to block the integrated groove toward the opposite side (the side _{forming an angle of 360 ° −θ 3).
The constriction 914 is seen from the side of the bent portion 90'at an angle (θ 4} ) of less than 180 ° inside the groove in which the grooves 9A and 9B are integrated when viewed in a plan view as described above. A polyhedral projecting portion is formed and configured so as not to block the integrated groove toward the opposite side (the side _{forming an angle of 360 ° −θ 4).}

The angles θ ₁ , θ ₂ , θ ₃ and θ ₄ satisfy the conditions of 0 ° <θ ₁ , θ ₂ , θ ₃ , θ ₄ <180 °, and θ ₁ + θ ₂ + θ ₃ + θ _{4 = 360 °.} If this is not particularly limited, it may be less than 90 ° (in other words, an acute angle), 90 ° (in other words, a right angle), or greater than 90 ° (in other words, an obtuse angle). )good.
Generally, the _{smaller the angles θ 1} , θ ₂ , θ ₃ or θ ₄ , the more remarkable the effect of the present invention can be obtained.

The printing plate 2 is the same as the printing plate 1 shown in FIG. 1 except that the grooves 9A and 9B share the bent portion 90 with each other.

FIG. 4 is a plan view schematically showing an enlarged region where the groove is formed for still another example of the printing plate used in the present invention.
The printing plate 3 shown here has fine linear grooves 9A and 9B on its surface 3a, and is an intaglio plate.
The grooves 9A and 9B are both similar to the groove 9 shown in FIG. 1, and are bent like the groove 9. The grooves 9A and 9B may be the same as or different from each other.
The printing plate 3 is the same as the printing plate 2 shown in FIG. 3, except that the grooves 9A and 9B intersect with each other without sharing the bent portion 90.

The groove 9A is bent at an angle θ ₁ (0 ° <θ ₁ <180 °) at the bent portion 90.
The groove 9B is bent at an angle θ ₂ (0 ° <θ ₂ <180 °) at the bent portion 90.

The number of grooves 9A and 9B in the printing plate 3 may be only one or two or more, respectively.
When the number of grooves 9A and 9B in the printing plate 3 is two or more, it is preferable that the grooves 9A and 9B are provided in a mesh shape.

The groove 9A has a constriction 911 on the side of the bent portion 90 at an angle (θ _{1) of less than 180 °.}
Similarly, the groove 9B has a constriction 912 on the side of the bent portion 90 at an angle (θ _{2) of less than 180 °.}
The constriction 911 and the constriction 912 are also formed in the same manner as in the case of the constriction 91 in the printing plate 1.
More specifically, when the constriction 911 is viewed in a plan view as described above, the constriction 911 is located inside the groove 9A from the side forming _{an angle (θ 1) of less than 180 ° of the bent portion 90 to the opposite side (θ 1).} A polyhedral projecting portion is formed and configured so as not to block the groove 9A toward the side forming an angle of 360 ° −θ _1).
When the constriction 912 is viewed in a plan view as described above, the constriction 912 is located inside the groove 9B _{from the side forming an angle (θ 2} ) of less than 180 ° of the bent portion 90 to the opposite side (360 ° −θ ₂ ). A polyhedral projecting portion is formed and configured so as not to block the groove 9B toward the angled side).

The grooves 9A and 9B have intersections that intersect each other in the vicinity of the bent portion 90 (in FIG. 4, two intersections are provided above and below the bent portion 90). It can be said that the grooves 9A and 9B also have a bent portion at this intersection. The bent portion at these intersections is the same as the bent portion (bent portion 90 or bent portion 90') shown in FIG.

FIG. 5 is a plan view schematically showing an enlarged region where the groove is formed for still another example of the printing plate used in the present invention.
In FIGS. 1 to 4, when viewed in a plan view as described above, the shape of the constriction is formed only by a combination of straight lines. On the other hand, in the bent portion 80 of the printing plate 4 shown in FIG. 5, the constriction 81 of the groove 8 is formed only by a curved line when viewed in a plan view as described above. The printing plate 4 is the same as the printing plate 1 shown in FIG. 1 except that the shape of the constriction is different in this way. Reference numeral 4a indicates the surface of the printing plate 4.

When the constriction 81 is viewed in a plan view as described above, the constriction 81 has an angle (θ) of less than 180 ° of the bent portion 80 from the side forming the opposite side (360 ° −θ) inside the groove 8. A non-polyhedral projecting portion is formed and configured so as not to block the groove 8 toward the forming side).

In the groove 8 of the printing plate 4, as in the case of the groove 9 of the printing plate 1 shown in FIGS. 1 and 2, it is assumed that the protruding portion 81 is not formed, and the bent portion (corner portion) of the groove 8 is formed. ) And the tip of the protruding portion 81 can be specified. Therefore, the length of the protruding portion 81 is defined in the same manner as the length of the protruding portion 91 of the printing plate 1.
On the other hand, the width of the protruding portion 81 is gradually narrowed toward the tip of the protruding portion 81. In this way, when the width of the protruding portion fluctuates, the maximum width of the protruding portion (in FIG. 4, the width at the portion farthest from the tip of the protruding portion 81) is set so that the higher effect of the present invention can be obtained. , It is preferable to adjust as appropriate.
The protrusion 81 may have a region in which the width thereof does not gradually narrow toward the tip of the protrusion 81 and does not change.

As a printing plate in which the shape of the constriction is formed only by a curved line when viewed in a plan view as described above, other than those shown in FIG. 5, for example, in FIGS. 3 and 4, the same as those shown in FIG. Some have changed the shape of the constriction. In this case, when one printing plate has constrictions in a plurality of places (multiple protrusions), the shapes of all the constrictions may be changed, or only a part of the constrictions may be changed. May be good.

The printing plate used in the present invention is not limited to the one shown in FIGS. 1 to 5, and a part of the configuration is changed in the printing plate shown in FIGS. It may be deleted or added.

For example, FIGS. 1 to 5 show a printing plate having a groove in which the shape of the constriction is formed only by a straight line or a curved line when viewed in a plan view as described above. It may be a printing plate whose shape is formed by a combination of straight lines and curves.
Further, FIGS. 1 to 4 show a printing plate in which the protruding portion forming the constriction is polyhedral, but for example, the protruding portion has a polyhedral shape with rounded corners. It may be a printing plate having another shape.
Further, in FIGS. 3 to 4, the constrictions of the plurality of places of one printing plate all have the same shape, but for example, the constrictions of a plurality of places of one printing plate have the same shape only partially. Or they may all have different shapes.

The printing plate used in the present invention can be produced by a photolithography method or the like in the same manner as in the case of a known printing plate (intaglio) except that a groove is formed as described above.
For example, plate making data as a design drawing of a target printing plate having a groove having a constriction is produced. Separately, a resist layer is formed on the surface of a metal plate which is a base material of a printing plate, and the resist layer is exposed to light by irradiating a laser beam reflecting the above plate-making data to form a resist film. Then, this resist film is developed to form a resist pattern. Next, the surface of the metal plate not coated with the developed resist film is etched, and all the resist film (resist pattern) is further removed. As described above, the desired printing plate can be obtained by forming a groove having a constriction on the surface of the metal plate by reflecting the above plate making data. The surface of the printing plate may be subjected to a treatment such as plating or polishing, if necessary.

In order to form a groove having a constriction in the printing plate, a groove having a similar constriction may be designed in the plate making data. For example, in the case of manufacturing a printing plate as shown in FIGS. 1 to 5, a groove having a constriction shown in these figures and a groove similar to the groove may be designed in the plate making data. That is, FIGS. 1 to 5 can be regarded as plate making data for manufacturing a printing plate.

However, in some cases, when a printing plate is manufactured based on the plate making data, it may not be possible to form a groove faithfully to the plate making data. For example, when trying to form a groove as shown in FIG. 1, even if plate making data in which a similar groove is designed is used, a groove is formed as shown in FIG. 5 instead of the groove as shown in FIG. Sometimes. In such a case, at the stage of plate making data, it is advisable to design the groove by emphasizing the constriction, for example, by widening the width of the protruding portion to be the constriction or increasing the length of the protruding portion.

In the printing pattern forming method of the present invention, printing may be performed using the printing plate, and for example, all methods using an intaglio such as an offset printing method and a gravure offset printing method can be applied. At the time of printing, the grooves in the printing plate (intaglio) are filled with ink, and the ink is transferred directly to the printing object or transferred to an offset roll and then transferred from the offset roll to the printing object. To form a print pattern.

FIG. 6 is an enlarged plan view schematically showing an example of a printing pattern formed by using the printing plate 1 shown in FIG. 1 or the printing plate 4 shown in FIG.
The printing pattern shown here is formed by a thin line 99 having a bent portion 909 on the surface 109a of the printing object 109, and the angle formed by the bent portion 909 is such that the bent portion 90 is formed in the printing plate 1 or the printing plate 4. It is the same as the angle made.
The thin line 99 is a printing layer formed by drying the ink transferred by the printing plate 1 or the printing plate 4.

Thin line 99 is formed to reflect the shape of the groove of the plate 1 or the printing plate 4, in the printing pattern, the width D _L of the thin line 99 in the bending portion 909 is completely or substantially, expansion suppressing ing. In FIG. 6, the width of the thin line 99 other than the bent portion 909 is shown by reference numeral W _L.

In the bending portion 909, when the enlargement of the width _{D L} of the thin line 99 is completely suppressed, the _{"D L = W 1 / sin (} θ / 2) ".

On the other hand, FIG. 9 is an enlarged plan view schematically showing an example of a printing pattern formed by using a conventional printing plate. Here, the "conventional printing plate" is the same as the printing plate 1 shown in FIG. 1 or the printing plate 4 shown in FIG. 5, except that the groove does not have a constriction.
The print pattern in this case is formed by a thin line 99'having a bent portion 909', and the thin line 99'is a print layer formed by drying the ink.
As shown here, the width _{D L} 'of fine line 99 at the' bent part 909 'is significantly wider than the width _{D L} of the thin line 99 shown in FIG. 6 _(D L _{<D L'),} I enlarged ing.

FIG. 7 is an enlarged plan view schematically showing an example of a printing pattern formed by using the printing plate 2 shown in FIG.
The print pattern shown here is formed by thin lines 99A and 99B on the surface 109a of the print object 109.
The thin lines 99A and 99B are printing layers formed by drying the ink transferred by the printing plate 2.

It can be considered that the thin wires 99A and 99B each have a bent portion 909 independently, and the thin wires 99A and 99B together have two bent portions 909'. The thin lines 99A and 99B can be regarded as bent at these bent portions (bent portion 909 and bent portion 909') as a whole, and the angle formed by these bent portions 909 and bent portion 909'is printed. In plate 2, it is the same as the angle formed by the bent portion 90 and the bent portion 90'.
Thin lines 99A and 99B is formed to reflect the shape of the groove of the plate 2, in the printing pattern, a fine line 99A and the width _{D L1} of 99B in the bent portion 909, at the bent portion 909 ', thin lines 99A and the width D _L2 thin lines 99B are integrated are both completely or substantially, expansion is suppressed.

In the bending portion 909, when the enlargement of the width DL ₁ fine line 99A and 99B are completely suppressed, _{"D L1 = W 1 / sin (} θ 1/2) " or _"D L1 ₌ W 1 / sin (θ _2/2) becomes ".
Further, the bent portion 909 ', when expanded fine line 99A and 99B is the width DL ₂ of thin lines together are suppressed completely, _{"D L2 = W 1 / sin (} θ 3/2) " or the _{"D L2 = W 1 / sin (} θ 4/2) ".

FIG. 8 is an enlarged plan view schematically showing an example of a printing pattern formed by using the printing plate 3 shown in FIG.
The printing pattern shown here is formed by thin lines 99A and 99B having a bent portion 909 on the surface 109a of the printing object 109, and the angle formed by the bent portion 909 is the angle formed by the bent portion 90 in the printing plate 3. Is the same as.
The thin lines 99A and 99B are printing layers formed by drying the ink transferred by the printing plate 3.
In the printing pattern, thin lines 99A and 99B the width _{D L3} of at the bent portion 909 is completely or substantially, expand suppressed.

In the bending portion 909, when the enlargement of the width DL ₃ fine lines 99A and 99B is completely suppressed, _{"D L3 = W 1 / sin (} θ 1/2) " or _"D L3 ₌ W 1 / sin (θ _2/2) becomes ".

Further, the thin lines 99A and 99B have intersections that intersect each other in the vicinity of the bent portion 909 (in FIG. 8, they have two intersections above and below the bent portion 909). It can be said that the thin wires 99A and 99B also have a bent portion at this intersection. The bent portion at these intersections is the same as the bent portion (bent portion 909 or bent portion 909') shown in FIG. 7, and the width of the thin wire in which the thin wires 99A and 99B are integrated at the bent portion. _DL4 and _DL5 are also completely or almost completely suppressed in expansion.

In the printing patterns shown in FIGS. 6 to 8, the widths of the thin lines (thin line 99, thin line 99A, thin line 99B) are the same in the portion other than the bent portion, but the width is the same in the portion other than the bent portion. The width of the thin line may vary regardless of the site.

Further, in the printing patterns shown in FIGS. 6 to 8, the thin lines (thin line 99, thin line 99A, thin line 99B) are formed to reflect the shape of the groove of the printing plate. Therefore, in the bent portion of the thin wire, the expansion of the width of the thin wire is not completely or almost observed. However, this is just an example. According to the present invention, a slight increase in the width of the thin wire may be observed at the bent portion of the thin wire. However, unlike the case shown in FIG. 9, for example, the expansion of the width in this case is very small.

The formed print pattern has a mesh shape. For example, as shown in FIG. 7 or 8, two thin lines having the same width are used independently, and these thin lines are integrated to share a bent portion. (In other words, two straight thin lines intersect). In this case, the expansion of the width of the thin line at the bent portion at the intersection is completely suppressed (in other words, the thin line having the desired shape is completely formed reflecting the shape of the groove of the printing plate). assuming is being), the area S of the bent portion 'is the width W _L of the fine line other than the bent portion, the following formula:
S'= W _L x W _L = W _L ²
Can be calculated by

On the other hand, the when the enlargement of the width of the thin line in the bent portion is not completely suppressed, when a particular D _L0 width D _L of the thin line in the bent portion, by the width D _L0, the bent portion Area S is the following formula:
_{S = D L0 × D L0 /} 2 = D L0 2/2
Can be calculated by

Therefore, the expansion ratio E of the area of the bent portion in this case can be calculated by the following formula (M1). The enlargement ratio E of this area is, for example, a guideline for the conspicuousness of the bent portion as the width of the thin line is increased, and is an index of the visual suppression effect of the thin metal line on the touch panel described later.
E = S / S'= D _L0 ² /2W _L ² ... (M1)

In the print pattern formed by the present invention, the width of the thin line (print layer) other than the bent portion is not particularly limited, but is preferably 1 to 10 μm, more preferably 2 to 7 μm, and 3 to 3 to 7. It is particularly preferably 5 μm. The thin wire having the width equal to or more than the lower limit value can be formed more stably without being accompanied by various shape abnormalities such as disconnection. A thin line whose width is equal to or less than the upper limit value has a higher effect of suppressing unintended expansion of the width at the bent portion.

In the print pattern formed by the present invention, the height of the fine lines (thickness of the print layer) is not particularly limited, but is preferably 0.01 to 0.5 μm, and is preferably 0.05 to 0.3 μm. It is more preferable, and 0.07 to 0.1 μm is particularly preferable. A thin wire having a height equal to or higher than the lower limit value can be formed more stably without being accompanied by various shape abnormalities such as disconnection. A thin line having a height equal to or less than the upper limit value has a higher effect of suppressing an unintended expansion of the width at the bent portion.
The height of the thin line can be adjusted by adjusting the amount of ink filled in the groove of the printing plate, that is, the depth of the groove of the printing plate.

The ink used in the present invention for filling the groove of the printing plate can be arbitrarily selected depending on the intended purpose, and is not particularly limited.
However, when the temperature is 25 ° C. and the shear rate is 0.1 s ^{-1 to} 1000 s ^-1 , the shear viscosity of the ink is preferably 0.1 Pa · s or more, and is 0.5 Pa · s or more. Is more preferable, and 1 Pa · s or more is particularly preferable. When the shear viscosity of the ink is at least the above lower limit value, a higher effect of suppressing an unintended expansion of the width of the thin line at the bent portion of the thin line can be obtained.
On the other hand, the shear viscosity of the ink is preferably 20 Pa · s or less, more preferably 10 Pa · s or less, and particularly preferably 3 Pa · s or less. When the viscosity of the ink is not more than the upper limit value, it becomes easier to form fine lines (printing patterns).

In the present invention, the shear viscosity of the ink when the temperature is 25 ° C. and the shear rate is 0.1 s ^{-1 to} 1000 s ^-1 is an arbitrary lower limit of any of the above and an upper limit of any of the above. It can be adjusted as appropriate so that the numerical range is determined by combining with.
For example, the shear viscosity of the ink can be preferably 0.1 to 20 Pa · s, more preferably 0.5 to 10 Pa · s, and particularly preferably 1 to 3 Pa · s. This is an example of a preferable numerical range of the shear viscosity of the ink.

The printing pattern forming method of the present invention may have a printing step of printing using the printing plate, and may have a step other than the printing step known in the art. ..
Further, the formed print pattern may be subjected to post-treatment such as drying treatment and heat treatment, if necessary. The post-treatment may be aimed at solidifying the inks constituting the print pattern.

In the method for forming a print pattern of the present invention, for example, as an ink, a composition as a raw material for forming a metal layer (in this specification, it may be abbreviated as "metal ink composition") is used. It is suitable for application when forming a metal layer. In this case, a wiring board having conductive thin wires (wiring) can be manufactured by forming a fine wire-shaped metal layer pattern, that is, a conductive pattern on the substrate. Such a wiring board is useful as a member such as a touch panel and an electromagnetic wave shield in various electronic devices. As an example of the wiring board in this case, for example, a transparent substrate provided with fine metal wires such as silver and copper as electrodes, and the fine metal wires forming a mesh (mesh) can be mentioned.

If the width of the thin metal wire is wider than the desired width at the bent portion of the thin metal wire, other problems may occur. For example, when a wiring board is used as a member of a touch panel, a thin metal wire is used as an electrode on a transparent substrate. A thin metal wire designed not to be visually recognized by the user becomes easily visible at the bent portion.
On the other hand, by applying the printing pattern forming method of the present invention, such expansion of the width of the thin metal wire is suppressed, and a wiring board for a touch panel can be satisfactorily manufactured.
Hereinafter, a metal ink composition for forming a thin metal wire will be described.

<Metal ink composition>
The metal type of the fine metal wire is not particularly limited, and may be, for example, either a simple substance metal or an alloy.
Among them, when a wiring board is manufactured by forming a fine metal wire, the metal type is preferably silver or copper, and more preferably silver.

The thin metal wire (metal layer) is a pattern of a layer (composition layer) of a metal ink composition as a printing pattern at a target location on a base material (substrate) by the above-mentioned method for forming a printing pattern of the present invention. Can be formed by appropriately selecting and performing a solidification treatment such as a drying treatment or a heating (baking) treatment on the composition layer. The heat treatment may also be performed as a drying treatment.
The pattern of the fine metal wire (metal layer) is the same as the pattern of the composition layer in the previous stage.

Examples of the metal ink composition include a metal ink composition in which one or both of a metal and a metal forming material are blended.
The metal in the metal ink composition and the material for forming the metal may be only one kind, may be two or more kinds, and when there are two or more kinds, the combination and the ratio thereof can be arbitrarily adjusted.

The metal (single metal or alloy) to be blended is preferably in the form of particles or fibers (tube-like, wire-like, etc.), more preferably nanoparticles or nanoparticles, and silver nanoparticles, silver nanos, etc. It is more preferably a wire, copper nanoparticles or copper nanoparticles, and particularly preferably silver nanoparticles or silver nanoparticles.
In the present specification, the "nanoparticle" means a particle having a particle size of 1 nm or more and less than 1000 nm, preferably 1 to 100 nm, and the "nanowire" has a width of 1 nm or more and less than 1000 nm, preferably. It means a wire having a diameter of 1 to 100 nm.

The material for forming the metal to be blended may be any material that has a corresponding metal atom (element) and produces a metal by a structural change such as decomposition. Examples of such metal forming materials include metal salts, metal complexes, organometallic compounds (compounds having a metal-carbon bond), and the like. The metal salt and the metal complex may be either a metal compound having an organic group or a metal compound having no organic group. Among them, the metal forming material is preferably a metal salt, more preferably a silver salt or a copper salt, and particularly preferably a silver salt.

The metal ink composition is preferably in a liquid state, preferably in which at least the metal forming material is blended, more preferably not containing a resin component such as a binder, and the metal forming material is uniformly dispersed. Is particularly preferable.

By using a metal forming material, a metal is generated from this material, and a metal layer containing this metal as a main component is formed. In the metal layer in this case, preferably, by not using the resin component, the ratio of the metal can be sufficiently increased so that the metal layer can be regarded as apparently composed only of the metal. In this case, for example, the ratio of the metal in the metal layer is preferably 97% by mass or more, more preferably 98% by mass or more, and particularly preferably 99% by mass or more. The upper limit of the ratio of the metal in the metal layer is, for example, 100% by mass, 99.9% by mass, 99.8% by mass, 99.7% by mass, 99.6% by mass, 99.5% by mass, 99. It can be any of 4% by mass, 99.3% by mass, 99.2% by mass and 99.1% by mass, but is not limited thereto.

The metal ink composition is preferably a silver ink composition in which a material for forming metallic silver is blended.
The material for forming metallic silver is decomposed by heating or the like to form metallic silver.

-Silver ink composition [silver carboxylate]
Examples of the material for forming metallic silver include silver carboxylate having a group represented by the formula "-COOAg".
The silver carboxylate is not particularly limited as long as it has a group represented by the formula "-COOAg". For example, the number of groups represented by the formula "-COOAg" in one molecule may be only one or two or more. Further, the position of the group represented by the formula "-COOAg" in silver carboxylate is not particularly limited.
In the present invention, one type of silver carboxylate may be used alone, two or more types may be used in combination, and when two or more types are used in combination, the combination and ratio thereof can be arbitrarily adjusted.

The silver carboxylate is represented by silver β-ketocarboxylate represented by the following general formula (1) (hereinafter, may be abbreviated as “silver β-ketocarboxylate (1)”) and the following general formula (4). It is preferably one or more selected from the group consisting of silver carboxylate (hereinafter, may be abbreviated as "silver carboxylate (4)").
In this specification, the description of "silver carboxylate" is not limited to "silver β-ketocarboxylate (1)" and "silver carboxylate (4)" unless otherwise specified. Inclusive, it shall mean "silver carboxylate having a group represented by the formula" -COOAg "".

（式中、Ｒは１個以上の水素原子が置換基で置換されていてもよい炭素数１〜２０の脂肪族炭化水素基若しくはフェニル基、水酸基、アミノ基、又は一般式「Ｒ^１−ＣＹ^１ _２−」、「ＣＹ^１ _３−」、「Ｒ^１−ＣＨＹ^１−」、「Ｒ^２Ｏ−」、「Ｒ^５Ｒ^４Ｎ−」、「（Ｒ^３Ｏ）_２ＣＹ^１−」若しくは「Ｒ^６−Ｃ（＝Ｏ）−ＣＹ^１ _２−」で表される基であり；
Ｙ^１はそれぞれ独立にフッ素原子、塩素原子、臭素原子又は水素原子であり；Ｒ^１は炭素数１〜１９の脂肪族炭化水素基又はフェニル基であり；Ｒ^２は炭素数１〜２０の脂肪族炭化水素基であり；Ｒ^３は炭素数１〜１６の脂肪族炭化水素基であり；Ｒ^４及びＲ^５はそれぞれ独立に炭素数１〜１８の脂肪族炭化水素基であり；Ｒ^６は炭素数１〜１９の脂肪族炭化水素基、水酸基又は式「ＡｇＯ−」で表される基であり；
Ｘ^１はそれぞれ独立に水素原子、炭素数１〜２０の脂肪族炭化水素基、ハロゲン原子、１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはベンジル基、シアノ基、Ｎ−フタロイル−３−アミノプロピル基、２−エトキシビニル基、又は一般式「Ｒ^７Ｏ−」、「Ｒ^７Ｓ−」、「Ｒ^７−Ｃ（＝Ｏ）−」若しくは「Ｒ^７−Ｃ（＝Ｏ）−Ｏ−」で表される基であり；
Ｒ^７は、炭素数１〜１０の脂肪族炭化水素基、チエニル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはジフェニル基である。）

(In the formula, R is an aliphatic hydrocarbon group or phenyl group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a hydroxyl group, an amino group, or the general formula "R ^1- CY". ¹ ₂ − ”,“ CY ¹ ₃ − ”,“ R ¹ − CHY ¹ − ”,“ R ² O − ”,“ R ⁵ R ⁴ N − ”,“ (R ³ O) ₂ CY ¹ − ”or“ It is a group represented by "R ^6- C (= O) -CY ¹ _2-";
Y ¹ is independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom; R ¹ is an aliphatic hydrocarbon group or a phenyl group having 1 to 19 carbon atoms; R ² is a fat having 1 to 20 carbon atoms. Group hydrocarbon groups; R ³ is an aliphatic hydrocarbon group having 1 to 16 carbon atoms; R ⁴ and R ⁵ are independently aliphatic hydrocarbon groups having 1 to 18 carbon atoms; R ⁶ is an aliphatic hydrocarbon group having 1 to 18 carbon atoms. An aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula "AgO-";
X ¹ is an independently hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, and a phenyl group or a benzyl group, a cyano group, N in which one or more hydrogen atoms may be substituted with a substituent. -Phenyl-3-aminopropyl group, 2-ethoxyvinyl group, or general formula "R ⁷ O-", "R ⁷ S-", "R ^7- C (= O)-" or "R ^7- C ( = O) -O- "is a group represented by;
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or a diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. )

（式中、Ｒ^８は炭素数１〜１９の脂肪族炭化水素基、カルボキシ基又は式「−Ｃ（＝Ｏ）−ＯＡｇ」で表される基であり、前記脂肪族炭化水素基がメチレン基を有する場合、１個以上の前記メチレン基はカルボニル基で置換されていてもよい。）

(In the formula, R ⁸ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms, a carboxy group or a group represented by the formula "-C (= O) -OAg", and the aliphatic hydrocarbon group is a methylene group. If, one or more of the methylene groups may be substituted with a carbonyl group.)

(Silver β-ketocarboxylate (1))
The silver β-ketocarboxylate (1) is not particularly limited as long as it is represented by the general formula (1).
Silver β-ketocarboxylate (1) is 2-methylacetoacetic acid silver (CH _3- C (= O) -CH (CH ₃ ) -C (= O) -OAg), silver acetoacetic acid (CH _3- C (=)). O) -CH _2- C (= O) -OAg), silver 2-ethylacetoacetic acid (CH _3- C (= O) -CH (CH ₂ CH ₃ ) -C (= O) -OAg), silver propionyl acetate (CH ₃ CH _2- C (= O) -CH _2- C (= O) -OAg), silver isobutyryl acetate ((CH ₃ ) ₂ CH-C (= O) -CH _2- C (= O)- OAg), silver pivaloyl acetate ((CH ₃ ) ₃ C-C (= O) -CH _2- C (= O) -OAg), silver caproyl acetate (CH ₃ (CH ₂ ) ₃ CH _2- C (= O) ) -CH _2- C (= O) -OAg), 2-n-silver butylacetoacetate (CH _3- C (= O) -CH (CH ₂ CH ₂ CH ₂ CH ₃ ) -C (= O) -OAg ), 2-benzyl acetoacetate silver _{(CH 3 -C (= O)} -CH (CH 2 C 6 H 5) -C (= O) -OAg), silver benzoylacetate _{(C 6 H 5 -C (=} O ) -CH _2- C (= O) -OAg), silver pivaloylacetoacetate ((CH ₃ ) ₃ C-C (= O) -CH _2- C (= O) -CH _2- C (= O) -OAg ), Silver Isobutyrylacetoacetic Acid ((CH ₃ ) ₂ CH-C (= O) -CH _2- C (= O) -CH _2- C (= O) -OAg), 2-Acetyl Pivaloyl Acetate Silver ((CH ₃ ) ₃ C-C (= O) -CH (-C (= O) -CH ₃ ) -C (= O) -OAg), 2-acetylisobutyryl silver acetate ((CH ₃ )) ₂ CH-C (= O) -CH (-C (= O) -CH ₃ ) -C (= O) -OAg) or silver acetate dicarboxylate (AgO-C (= O) -CH _2- C ( = O) -CH _2- C (= O) -OAg) is preferable.

In a conductor (metal silver) formed by a solidification treatment such as a drying treatment or a heating (calcination) treatment using silver β-ketocarboxylate (1), the concentration of residual raw materials and impurities can be further reduced. In such a conductor, the smaller the amount of raw materials and impurities, the better the contact between the formed metallic silver, for example, the easier the conduction, and the lower the resistivity.

Silver β-ketocarboxylate (1) can be decomposed at a low temperature of preferably 60 to 210 ° C., more preferably 60 to 200 ° C. to form metallic silver without using a reducing agent or the like known in the art. .. Then, silver β-ketocarboxylate (1) is decomposed at a lower temperature to form metallic silver when used in combination with a reducing agent. The reducing agent will be described later.

In the present invention, one type of silver β-ketocarboxylate (1) may be used alone, two or more types may be used in combination, and when two or more types are used in combination, the combination and ratio thereof shall be determined. It can be adjusted arbitrarily.

(Silver carboxylate (4))
The silver carboxylate (4) is not particularly limited as long as it is represented by the general formula (4).
The silver carboxylate (4) is silver pyruvate (CH _3- C (= O) -C (= O) -OAg), silver acetate (CH _3- C (= O) -OAg), silver butyrate (CH _3). -(CH ₂ ) _2- C (= O) -OAg), silver isobutyrate ((CH ₃ ) ₂ CH-C (= O) -OAg), silver 2-ethylhexanoate (CH _3- (CH ₂₎₎ ) _3- CH (CH ₂ CH ₃ ) -C (= O) -OAg), silver neodecanoate (for example, CH _3- (CH ₂ ) _5- C (CH ₃ ) _2- C (= O) -OAg), with silver oxalate (AgO-C (= O) -C (= O) -OAg), or malonate silver _{(AgO-C (= O)} -CH 2 -C (= O) -OAg) It is preferable to have. Also, 2 of the silver oxalate (AgO-C (= O) -C (= O) -OAg) and malonic silver _{(AgO-C (= O)} -CH 2 -C (= O) -OAg) Of the groups represented by the formula "-COOAg", one of which is the group represented by the formula "-COOH" (HO-C (= O) -C (= O) -OAg, HO -C (= O) -CH _2- C (= O) -OAg) is also preferable.

Similar to silver β-ketocarboxylate (1), silver carboxylate (4) also contains residual raw materials and impurities in the conductor (metal silver) formed by solidification treatment such as drying treatment and heating (baking) treatment. The concentration can be further reduced. Then, silver carboxylate (4) is also decomposed at a lower temperature to form metallic silver when used in combination with a reducing agent.

In the present invention, one type of silver carboxylate (4) may be used alone, two or more types may be used in combination, and when two or more types are used in combination, the combination and ratio thereof may be arbitrary. Can be adjusted.

The silver carboxylate is silver 2-methylacetate acetate, silver acetoacetate, silver 2-ethylacetate acetate, silver propionyl acetate, silver isobutyryl acetate, silver pivaloyl acetate, silver caproyl acetate, silver 2-n-butylacetate acetate, 2-benzylacetate. Silver acetate, silver benzoyl acetate, silver pivaloylacetacetate, silver isobutyryl acetoacetate, silver acetonedicarboxylate, silver pyruvate, silver acetate, silver butyrate, silver isobutyrate, silver 2-ethylhexanoate, silver neodecanoate, oxalate It is preferably one or more selected from the group consisting of silver acid acid and silver malonate.
Among these silver carboxylates, silver 2-methylacetoacetic acid and silver acetoacetic acid have excellent compatibility with nitrogen-containing compounds (among them, amine compounds) described later, and are particularly suitable for increasing the concentration of silver ink compositions. It can be mentioned as a compound.

[Nitrogen-containing compound]
The silver ink composition is preferably one in which a nitrogen-containing compound is further blended in addition to the metal silver forming material, particularly when the metal silver forming material is the silver carboxylate.
The nitrogen-containing compound is an amine compound having 25 or less carbon atoms (hereinafter, may be abbreviated as "amine compound") and a quaternary ammonium salt having 25 or less carbon atoms (hereinafter, abbreviated as "quaternary ammonium salt"). (May be), ammonia, an ammonium salt formed by reacting an amine compound with 25 or less carbon atoms with an acid (hereinafter, may be abbreviated as "ammine salt derived from an amine compound"), and ammonia reacting with an acid. One or more selected from the group consisting of ammonium salts (hereinafter, may be abbreviated as "ammonium-derived ammonium salts"). That is, the nitrogen-containing compound to be blended may be only one kind, may be two or more kinds, and when two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

(Amine compound, quaternary ammonium salt)
The amine compound has 1 to 25 carbon atoms and may be any of a primary amine, a secondary amine and a tertiary amine. The quaternary ammonium salt has 4 to 25 carbon atoms. The amine compound and the quaternary ammonium salt may be either chain-like or cyclic. Further, the number of nitrogen atoms constituting the amine moiety or the ammonium salt moiety (for example, the nitrogen atom constituting the amino group (-NH ₂ ) of the primary amine) may be one or two or more.

Among the amine compounds, examples of the primary amine include monoalkylamines, monoarylamines, mono (heteroaryl) amines, diamines, etc., in which one or more hydrogen atoms may be substituted with a substituent. Can be mentioned.
Among the amine compounds, examples of the secondary amine include dialkylamine, diarylamine, and di (heteroaryl) amine in which one or more hydrogen atoms may be substituted with a substituent.
Among the amine compounds, examples of the tertiary amine include trialkylamines and dialkylmonoarylamines in which one or more hydrogen atoms may be substituted with substituents.

Examples of the quaternary ammonium salt include tetraalkylammonium halide in which one or more hydrogen atoms may be substituted with a substituent.

The amine compound and the quaternary ammonium salt may be a chain amine compound and a quaternary organic ammonium salt, respectively, and the nitrogen atom constituting the amine moiety or the ammonium salt moiety has a ring skeleton structure (heterocyclic skeleton). It may be a heterocyclic compound which is a part of (structure). That is, the amine compound may be a cyclic amine, and the quaternary ammonium salt may be a cyclic ammonium salt. The ring (ring containing nitrogen atoms constituting the amine moiety or ammonium salt moiety) structure at this time may be either monocyclic or polycyclic, and the number of ring members (the number of atoms constituting the ring skeleton) is particularly limited. However, it may be either an aliphatic ring or an aromatic ring.
If it is a cyclic amine, preferred examples thereof include pyridine and the like.

In the primary amine, secondary amine, tertiary amine and quaternary ammonium salt, the "hydrogen atom which may be substituted with a substituent" is a nitrogen atom constituting an amine moiety or an ammonium salt moiety. It is a hydrogen atom other than the hydrogen atom bonded to. The number of substituents at this time is not particularly limited, and may be one, two or more, and all of the hydrogen atoms may be substituted with substituents. When the number of substituents is plural, these plurality of substituents may be the same or different from each other. That is, the plurality of substituents may all be the same, all may be different, or only some of them may be different. Further, the position of the substituent is not particularly limited.

Examples of the substituent in the amine compound and the quaternary ammonium salt include an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, a hydroxyl group, and a trifluoromethyl group (-CF ₃ ). Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

The amine compounds include n-propylamine, n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, isobutylamine, sec-butylamine, tert-butylamine, 3-aminopentane, 3-Methylbutylamine, 2-heptylamine, 2-aminooctane, 2-ethylhexylamine, 2-phenylethylamine, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, N-methyl-n-hexylamine, Diisobutylamine, N-methylbenzylamine, di (2-ethylhexyl) amine, 1,2-dimethyl-n-propylamine, N, N-dimethyl-n-octadecylamine or N, N-dimethylcyclohexylamine. Is preferable.
Among these amine compounds, 2-ethylhexylamine has excellent compatibility with the silver carboxylate, is particularly suitable for increasing the concentration of the silver ink composition, and is particularly suitable for reducing the surface roughness of the conductive layer. Listed as suitable.

(Ammonium salt derived from amine compound)
The ammonium salt derived from the amine compound is an ammonium salt formed by reacting the amine compound with an acid. The acid may be an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, or an organic acid such as acetic acid, and the type of acid is not particularly limited.
Examples of the ammonium salt derived from the amine compound include n-propylamine hydrochloride, N-methyl-n-hexylamine hydrochloride, N, N-dimethyl-n-octadecylamine hydrochloride and the like. Not limited.

(Ammonia-derived ammonium salt)
The ammonium salt derived from ammonia is an ammonium salt formed by reacting ammonia with an acid. Here, as the acid, for example, the same acid as in the case of the ammonium salt derived from the amine compound and the like can be mentioned.
Examples of the ammonia-derived ammonium salt include, but are not limited to, ammonium chloride.

In the present invention, the amine compound, the quaternary ammonium salt, the ammonium salt derived from the amine compound and the ammonium salt derived from ammonia may be used alone or in combination of two or more. Often, when two or more types are used in combination, the combination and ratio can be adjusted arbitrarily.
Then, as the nitrogen-containing compound, one selected from the group consisting of the amine compound, the quaternary ammonium salt, the ammonium salt derived from the amine compound and the ammonium salt derived from ammonia may be used alone. Two or more types may be used in combination, and when two or more types are used in combination, the combination and ratio can be arbitrarily adjusted.

When the nitrogen-containing compound is used, in the silver ink composition, the blending amount of the nitrogen-containing compound is preferably 0.3 to 15 mol, preferably 0.3 to 15 mol, per 1 mol of the blending amount of the metallic silver forming material. It is more preferably ~ 12 mol, particularly preferably 0.3-8 mol. When the blending amount of the nitrogen-containing compound is in such a range, the stability of the silver ink composition is further improved, and the quality of metallic silver is further improved. Further, metallic silver can be formed more stably without heat treatment at a high temperature.

[alcohol]
The silver ink composition is preferably one in which alcohol is further blended in addition to the metallic silver forming material, particularly when the metallic silver forming material is the silver carboxylate.

The alcohol is preferably acetylene alcohols represented by the following general formula (2) (hereinafter, may be abbreviated as "acetylene alcohol (2)").

（式中、Ｒ’及びＲ’’は、それぞれ独立に水素原子、炭素数１〜２０のアルキル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基である。）

(In the formula, R'and R'' are hydrogen atoms, alkyl groups having 1 to 20 carbon atoms, or phenyl groups in which one or more hydrogen atoms may be substituted with substituents, respectively.)

(Acetylene alcohol (2))
The acetylene alcohol (2) is not particularly limited as long as it is represented by the general formula (2).
Preferred acetylene alcohols (2) include, for example, 3,5-dimethyl-1-hexin-3-ol, 3-methyl-1-butyne-3-ol, 3-methyl-1-pentyne-3-ol, 2 -Propyne-1-ol, 4-ethyl-1-octyne-3-ol, 3-ethyl-1-heptin-3-ol and the like can be mentioned.

When acetylene alcohol (2) is used, the blending amount of acetylene alcohol (2) in the silver ink composition is preferably 0.01 to 0.7 mol per mole of the metallic silver forming material. It is more preferably 0.02 to 0.5 mol, and particularly preferably 0.02 to 0.3 mol. When the blending amount of the acetylene alcohol (2) is in such a range, the stability of the silver ink composition is further improved.

(Other alcohol)
As the alcohol, alcohol other than acetylene alcohol (2) may be used.
Examples of the alcohol include saturated aliphatic alcohols such as ethanol and 2-propanol.

As for the alcohol, one kind may be used alone, two or more kinds may be used in combination, and when two or more kinds are used in combination, the combination and ratio thereof can be arbitrarily adjusted.

[Reducing agent]
The silver ink composition is preferably one in which a reducing agent is further blended in addition to the metallic silver forming material, particularly when the metallic silver forming material is the silver carboxylate.
The reducing agent is oxalic acid (HOOC-COOH), the compound represented by hydrazine _{(H 2} N-NH 2) and the following general formula (5) (hereinafter, sometimes abbreviated as "compound (5)") One or more selected from the group consisting of.
HC (= O) -R ²¹ ... (5)
(In the formula, R ²¹ is an alkyl group having 20 or less carbon atoms, an alkoxy group or an N, N-dialkylamino group, a hydroxyl group or an amino group.)
That is, the reducing agent to be blended may be only one kind, may be two or more kinds, and when two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

The hydrazine as the reducing agent may be a monohydrate (H ₂ N-NH ₂ · H ₂ O).

Preferred reducing agents include, for example, formic acid (HC (= O) -OH); methyl formate (HC (= O) -OCH ₃ ), ethyl formate (HC (= O)-). Formic acid esters such as OCH ₂ CH ₃ ), butyl formate (HC (= O) -O (CH ₂ ) ₃ CH ₃ ); propanal (HC (= O) -CH ₂ CH ₃ ), butanal ( Aldehydes such as HC (= O)-(CH ₂ ) ₂ CH ₃ ), hexanal (HC (= O)-(CH ₂ ) ₄ CH ₃ ); formamide (HC (= O) -NH ₂ ), N, N-dimethylformamides (HC (= O) -N (CH ₃ ) ₂ ) and other formamides (represented by the formula "HC (= O) -N (-)-" Compound having a group); Formic acid and the like can be mentioned.

When a reducing agent is used, the blending amount of the reducing agent in the silver ink composition is preferably 0.04 to 3.5 mol per 1 mol of the blending amount of the metallic silver forming material, and 0.06 to 2. More preferably, it is 5 mol. When the blending amount of the reducing agent is in such a range, the silver ink composition can form metallic silver more easily and more stably.

[Other ingredients]
The silver ink composition may be a mixture of other components other than the metallic silver forming material, the nitrogen-containing compound, the alcohol and the reducing agent.
The other components in the silver ink composition can be arbitrarily selected depending on the intended purpose, and are not particularly limited. Examples of the other components include solvents other than alcohol, which can be arbitrarily selected depending on the type and amount of the compounded components.
As the other components in the silver ink composition, one type may be used alone, two or more types may be used in combination, and when two or more types are used in combination, the combination and ratio thereof may be arbitrary. Can be adjusted.

(solvent)
The solvent is not particularly limited as long as it is other than alcohol (those having no hydroxyl group).
However, the solvent is preferably liquid at room temperature. In addition, in this specification, "room temperature" means a temperature which is not particularly cooled or heated, that is, a normal temperature, and examples thereof include a temperature of 15 to 25 ° C.

Examples of the solvent include aromatic hydrocarbons such as toluene, o-xylene, m-xylene, and p-xylene; pentane, hexane, cyclohexane, heptane, octane, cyclooctane, nonane, decane, undecane, dodecane, tridecane, and the like. Aliper hydrocarbons such as tetradecane, pentadecane and decahydronaphthalene; halogenated hydrocarbons such as dichloromethane and chloroform; esters such as ethyl acetate, monomethyl glutarate, dimethyl glutarate; diethyl ether, tetrahydrofuran (THF), 1,2- Ethers such as dimethoxyethane (dimethyl cellosolve); ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone; nitriles such as acetonitrile; amides such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide and the like. ..

When the other component is used, the blending amount of the other component in the silver ink composition may be appropriately selected according to the type of the other component.
For example, when the other component is a solvent other than alcohol, the blending amount of the solvent may be selected according to the purpose such as the viscosity of the silver ink composition. However, usually, in the silver ink composition, the ratio of the compounding amount of the solvent to the total amount of the compounding components is preferably 50% by mass or less, more preferably 40% by mass or less, and 30% by mass or less. It is particularly preferable to have.
When the other component is a component other than the solvent, the ratio of the compounding amount of the other component to the total amount of the compounding component in the silver ink composition is preferably 10% by mass or less, preferably 5% by mass. More preferably, it is less than%.
The ratio of the blending amount of the other component to the total blending component is 0 mass, that is, even if the other component is not blended, the silver ink composition sufficiently exhibits its effect.

In the silver ink composition, all the compounding components may be dissolved, or some or all the components may be dispersed without being dissolved, but it is preferable that all the compounding components are dissolved. It is preferable that the undissolved components are uniformly dispersed.

Preferred silver ink compositions used in the present invention include, for example, a silver ink composition containing the metallic silver forming material, a nitrogen-containing compound, an alcohol and a reducing agent; the metallic silver forming material and the nitrogen-containing compound. , A silver ink composition containing an alcohol, a reducing agent, and a solvent other than alcohol.

-Method for Producing Silver Ink Composition The silver ink composition can be obtained by blending the material for forming metallic silver and other components. After blending each component, the obtained product may be used as it is as a silver ink composition, or if necessary, a silver ink composition may be obtained by continuously performing a known purification operation. In the present invention, particularly when silver β-ketocarboxylate (1) is used as a material for forming metallic silver, impurities that lower the conductivity are not generated or such impurities are not generated when each of the above components is blended. The amount of silver produced can be suppressed to an extremely small amount. Therefore, even if a silver ink composition that has not been refined is used, metallic silver having sufficient conductivity can be obtained.

When blending each component, all the components may be added and then mixed, some components may be added sequentially and mixed, or all components may be added sequentially and mixed. good. An example of a preferable compounding method for each component is shown below.

For example, in the case of producing a silver ink composition in which the metallic silver forming material, a nitrogen-containing compound, an alcohol and a reducing agent are blended, the metallic silver forming material is added to the nitrogen-containing compound, and then the reducing agent is added. Is then added, followed by alcohol. Further, when producing such a silver ink composition, it is preferable to add the reducing agent by dropping, and further, by suppressing fluctuations in the dropping rate, the surface roughness of metallic silver tends to be further reduced. It is in.
For example, in the case of producing a silver ink composition in which the metal silver forming material, the nitrogen-containing compound, alcohol, a reducing agent, and a solvent other than alcohol are blended, the nitrogen-containing compound is added to the nitrogen-containing compound in the above production method. It is preferable to produce by a method in which a material for forming metallic silver is added after the solvent is added.

The method of mixing the ingredients is not particularly limited, and the method of mixing by rotating a stirrer or a stirring blade or the like; a method of mixing using a mixer, a three-roll roll, a kneader or a bead mill or the like; A method or the like may be appropriately selected from known methods.
In the case of uniformly dispersing the undissolved components in the silver ink composition, it is preferable to apply, for example, the method of dispersing using the above-mentioned three rolls, kneader, bead mill or the like.

In the above-mentioned production method, the temperature in each step of adding and stirring the compounding components until the silver ink composition is obtained is not particularly limited as long as each compounding component is not deteriorated, but is −5 to 60 ° C. Is preferable. Then, the temperature may be appropriately adjusted according to the type and amount of the compounding component so that the mixture obtained by blending has a viscosity that makes it easy to stir.

In the above-mentioned production method, the total time (total of addition time and stirring time) when adding and stirring the compounding ingredients is not particularly limited as long as each compounding component is not deteriorated, but may be 10 minutes to 36 hours. preferable.

[carbon dioxide]
The silver ink composition may be further supplied with carbon dioxide. Such a silver ink composition has a high viscosity and is suitable for application to a printing method that requires thickening of ink.

Carbon dioxide may be supplied at any time during the production of the silver ink composition.
Then, in the present invention, for example, carbon dioxide is supplied to the first mixture formed by blending the metallic silver forming material and the nitrogen-containing compound to obtain a second mixture, and if necessary, the second mixture is subjected to. Further, it is preferable to blend the reducing agent to produce a silver ink composition. Further, when the alcohol or other components are blended, these can be blended at the time of producing either one or both of the first mixture and the second mixture, and can be arbitrarily selected depending on the purpose.

The carbon dioxide (CO ₂ ) supplied may be either gaseous or solid (dry ice), or both gaseous and solid. When carbon dioxide is supplied to the first mixture, it is presumed that the carbon dioxide dissolves in the first mixture and acts on the components in the first mixture to increase the viscosity of the obtained second mixture.

Further, in the present invention, it is also preferable to supply carbon dioxide to the mixture in which the metallic silver forming material, alcohol and nitrogen-containing compound are blended to produce a silver ink composition. In this case, the same method as described above can be adopted as the carbon dioxide supply method.

<Method of forming fine metal wire>
When a metal ink composition such as the silver ink composition is used as the ink, first, as described above, printing is performed using the metal ink composition and the printing plate, and the base material ( A pattern of a metal ink composition layer (composition layer) is formed as a printing pattern on a printing object such as a substrate).
Next, the obtained composition layer pattern is subjected to a solidification treatment such as a drying treatment or a heating (firing) treatment to form a fine metal wire (thin wire-shaped metal layer). By the solidification treatment, a thin metal wire having the same pattern as the pattern of the composition layer is obtained.

At the time of forming the fine metal wire, the base material may be heat-treated (annealed) before printing the metal ink composition. By heat-treating the base material, for example, when the metal ink composition is heated (baked), shrinkage of the base material is suppressed and dimensional stability is improved.
The conditions for the heat treatment of the base material before printing the metal ink composition may be appropriately adjusted according to the type of the base material, and are not particularly limited, but the heat treatment may be performed at 60 to 200 ° C. for 10 to 60 minutes. Preferably, for example, the conditions for the heating (baking) treatment of the metal ink composition at the time of forming the thin metal wire may be the same.

Further, when forming the fine metal wire, the surface of the base material may be plasma-treated before printing the metal ink composition. By plasma-treating the base material, bleeding of the metal ink composition may be suppressed.
The plasma treatment may be carried out by a known method. For example, in the case of atmospheric pressure plasma treatment, the plasma treatment can be carried out under conditions such as a voltage of 290 to 300 W and an air flow velocity of 1.0 to 5.0 m / min.

When the metal ink composition printed on the substrate is dried, it may be carried out by a known method. That is, the drying treatment may be performed, for example, under normal pressure, reduced pressure, or blowing conditions, and may be performed under any of an atmosphere and an inert gas atmosphere. The drying temperature is not particularly limited, and either heat drying or room temperature drying may be used. As a preferable drying method when heat treatment is not required, for example, a method of drying in the air at 18 to 30 ° C. and the like can be mentioned.

When the composition layer is heated (baked), the conditions may be appropriately adjusted according to the type of the compounding component of the metal ink composition. For example, when the metal ink composition is the silver ink composition, the heating temperature is usually preferably 60 to 370 ° C, more preferably 70 to 280 ° C. The heating time may be adjusted according to the heating temperature, but is usually preferably 1 minute to 24 hours, more preferably 1 minute to 12 hours. Among the materials for forming metallic silver, the silver carboxylate, particularly silver β-ketocarboxylate (1), is different from the material for forming metallic silver such as silver oxide, and uses a reducing agent known in the art. Even without it, it decomposes at low temperatures. Then, reflecting such a decomposition temperature, the silver ink composition can form metallic silver at an extremely lower temperature than the conventional one, as described above.

When the metal ink composition is printed on a substrate having low heat resistance and heated (baked), the heating temperature is preferably less than 130 ° C, more preferably 125 ° C or lower, and 120 ° C or lower. Is particularly preferable.

The method of heat treatment of the metal ink composition is not particularly limited. The heat treatment can be performed by, for example, heating by an electric furnace, heating by a heat-sensitive heat head, heating by far-infrared irradiation, heating by blowing a high-temperature gas, or the like. Further, the heat treatment may be performed in an atmosphere, an inert gas atmosphere, or a humidified condition. Then, the heat treatment may be performed under normal pressure, reduced pressure, or pressurized pressure.

In the present specification, "humidification" means artificially increasing the humidity unless otherwise specified, and preferably the relative humidity is 5% or more. It can be said that the relative humidity of 5% is clearly artificially increased because the humidity in the treatment environment becomes extremely low due to the high treatment temperature during the heat treatment.

Hereinafter, a method of heat treatment when the metal ink composition is a silver ink composition will be described.
When the heat treatment of the silver ink composition is performed under humidified conditions, the relative humidity is preferably 10% or more, more preferably 30% or more, further preferably 50% or more, and 70%. The above is particularly preferable, and it may be 90% or more or 100%. Then, the heat treatment under the humidifying condition may be performed by spraying high-pressure steam heated to 100 ° C. or higher. By heat-treating under humidified conditions in this way, higher-purity metallic silver can be formed in a short time.

The heat treatment of the silver ink composition may be performed in two steps. For example, in the first-step heat treatment, the silver ink composition is mainly dried instead of forming metallic silver, and in the second-step heat treatment, metallic silver is formed to the end.
In the first-stage heat treatment, the heating temperature may be appropriately adjusted according to the type of the compounding component of the silver ink composition, but is preferably 60 to 140 ° C, more preferably 70 to 130 ° C. preferable. The heating time may be adjusted according to the heating temperature, but is usually preferably 5 seconds to 12 hours, more preferably 30 seconds to 2 hours.
In the second step of heat treatment, the heating temperature may be appropriately adjusted according to the type of the compounding components of the silver ink composition so that metallic silver is formed well, but it may be 60 to 280 ° C. It is preferably 70 to 260 ° C., more preferably 70 to 260 ° C. The heating time may be adjusted according to the heating temperature, but is usually preferably 1 minute to 12 hours, more preferably 1 minute to 10 hours.
When the silver ink composition is printed on a substrate having low heat resistance and heated (baked), the heating temperature in the first and second heat treatments is preferably less than 130 ° C., 125. It is more preferably ° C. or lower, and particularly preferably 120 ° C. or lower.

The heat treatment of the silver ink composition described so far is performed in the gas phase, but when the heat treatment of the silver ink composition is performed in two steps, the heat treatment of the second step is the gas phase. It may be done in the liquid phase instead of inside. The silver ink composition that has been completely or to some extent dried after the first-step heat treatment can be brought into contact with the heated liquid to perform the second-step heat treatment without damaging its shape. The heat treatment of the silver ink composition in the liquid phase of the second step after the heat treatment of the first step is preferably performed by immersing the silver ink composition in the heated liquid. The heating temperature and heating time in the heat treatment in this liquid phase are the same as the heating temperature and heating time in the second stage heat treatment described above.
The heated liquid is preferably hot water (heated water), and the second-step heat treatment is performed by immersing the silver ink composition subjected to the first-step heat treatment in hot water, that is, by boiling water. It is preferable to do so.
When the second step heat treatment is performed in the liquid phase, the metallic silver formed by this heat treatment may be further dried.

When the second step heat treatment of the silver ink composition is carried out in the liquid phase, it is preferable that the first step heat treatment of the silver ink composition is carried out under non-humidified conditions.
In addition, in this specification, "non-humidification" means that the above-mentioned "humidification" is not performed, that is, the humidity is not artificially increased, and the relative humidity is preferably less than 5%. ..

When the heat treatment under humidified conditions is adopted, it is particularly preferable that the heat treatment of the silver ink composition is carried out by the following two-step method. That is, in the first-stage heat treatment, the silver ink composition is mainly dried under non-humidified conditions instead of forming metallic silver as described above, and in the second-stage heat treatment, under humidified conditions. It is particularly preferable to heat-treat the silver ink composition by forming the metallic silver to the end as described above.

When the second stage heat treatment is performed under humidified conditions, the heating temperature during the first stage heat treatment under non-humidified conditions is preferably 60 to 140 ° C., preferably 70 to 130 ° C. More preferred. The heating time is preferably 5 seconds to 1 hour, more preferably 30 seconds to 30 minutes, and particularly preferably 30 seconds to 10 minutes.
The heating temperature during the heat treatment under the second stage humidifying condition, which is performed after the heat treatment under the first stage non-humidifying condition, is preferably 60 to 140 ° C., and is preferably 70 to 130 ° C. Is more preferable. The heating time is preferably 1 minute to 2 hours, more preferably 1 minute to 1 hour, and particularly preferably 1 minute to 30 minutes.
When the silver ink composition is printed on a substrate having low heat resistance and heated (baked), the first stage heat treatment under non-humidified conditions and the second stage heat treatment under humidified conditions are performed. The heating temperature is preferably less than 130 ° C., more preferably 125 ° C. or lower, and particularly preferably 120 ° C. or lower.

As described above, as a preferable method for forming the fine metal wire, for example, a step of forming a pattern of a layer (composition layer) of the silver ink composition as a printing pattern using a silver ink composition and the above-mentioned composition. Examples thereof include those having a step of forming a fine wire of metallic silver (fine silver wire) from a layer.
Among them, as a preferable method for forming the fine metal wire, for example, a silver ink composition in which the silver carboxylate, preferably silver β-ketocarboxylate (1) is blended in the step of forming the fine metal wire. Examples thereof include those in which the layer is heat-treated under non-humidified conditions and then further heat-treated under humidified conditions or in contact with a heated liquid to form fine silver wires.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples shown below.

<< Formation of print pattern, formation of fine silver line >>
[Example 1]
<Manufacturing of printing plates>
By the procedure shown below, a printing plate having a groove having a constriction as shown in FIG. 3 was manufactured.
That is, a photosensitive resist composition was applied to the surface of a copper plate as a base material of a printing plate to form a resist layer. Next, a resist film was formed by irradiating the resist layer with a laser beam and exposing it to light so that a groove having a desired arrangement form was formed on the copper plate. Next, by developing this resist film, a desired resist pattern was formed. Next, the surface of the copper plate on which this resist pattern is formed is brought into contact with the etching solution, the surface of the copper plate not coated with the developed resist film is etched, and all the resist film (resist pattern) is removed. Grooves of the desired arrangement form were formed on the surface of the copper plate. Next, the surface of the copper plate on which the grooves are formed is chrome-plated, and the surface of the formed chrome-plated film is further polished to form a groove having a constriction as a printing plate on the surface in the desired arrangement form. A recessed plate having a thickness of 150 μm was obtained in preparation for the above.

In the production of this printing plate, the width W ₁ of the groove is 5 μm, the depth of the groove is 1.9 _{μm, the length L 1 of the} protrusion forming the constriction of the groove is 2.0 μm, and the protrusion. Plate making data was prepared so that the width L _{2 of the} portion was 1.0 μm, respectively, and a printing plate almost exactly as it was obtained was obtained.

<Manufacturing of silver ink composition>
2-Ethylhexylamine (1.45 times the molar amount of silver 2-methylacetate acetate described later) and n-hexane (1.63 times the molar amount of silver 2-methylacetate acetate described later) in a beaker. Was added in this order, and silver 2-methylacetate acetate was added to the beaker so that the liquid temperature became 50 ° C. or lower while rotating and stirring the mechanical stirrer.
After the addition of 2-methylacetate silver is completed, formic acid (0.5 times the molar amount of 2-methylacetate silver) is added dropwise in a beaker over 10 minutes while maintaining the same state. Then, after the dropping of formic acid was completed, the mixture was further stirred for 1.5 hours as it was.
Then, 3,5-dimethyl-1-hexin-3-ol (hereinafter, may be abbreviated as "DMHO") (0.032 times by molar amount with respect to silver 2-methylacetate acetate) and 4-ethyl-1. A mixture of −octyne-3-ol (hereinafter sometimes abbreviated as “EOO”) (0.004 times molar amount with respect to silver 2-methylacetate acetate) was added to the beaker, and after the addition was completed, the mixture was further added as it was. The silver ink composition was obtained by stirring for 5 minutes in the state of.
As the DMHO, "Surfinol 61" manufactured by Air Products Japan Co., Ltd. was used, and as the EOO, the one manufactured by Tokyo Chemical Industry Co., Ltd. was used.

Table 1 shows the types and ratios of each compounding ingredient. In Table 1, the “nitrogen-containing compound (molar ratio)” refers to the amount of the nitrogen-containing compound compounded per mole of the material for forming metallic silver (the number of moles) ([the number of moles of the nitrogen-containing compound] / [metal]. Number of moles of silver forming material]). Similarly, the "reducing agent (molar ratio)" is also the amount of the reducing agent compounded per mole of the metal silver forming material (the number of moles) ([the number of moles of the reducing agent] / [the mole of the metal silver forming material]. Number]). Similarly, "acetylene alcohol (2) (molar ratio)" is also the amount of acetylene alcohol (2) compounded (number of moles) per mol of the compounding amount of the metallic silver forming material ([number of moles of acetylene alcohol (2)]]. / [Number of moles of metallic silver forming material]). Similarly, the "solvent (molar ratio)" is also the blending amount (number of moles) of the solvent per mole of the blending amount of the metallic silver forming material ([the number of moles of the solvent] / [the number of moles of the metallic silver forming material]). Means.
In this embodiment, the "material for forming metallic silver" is "silver β-ketocarboxylate (1)".

Using a rheometer (“MCR-301” manufactured by Antonio Parr), the shear viscosity of the obtained silver ink composition was measured at a temperature of 25 ° C. and a shear rate of 0.1 s ^{-1 to 1000 s -1.} .. As a result, the shear ^{viscosity at a shear rate of 0.1 s -1} was 2.1 Pa · s, and the shear viscosity at a shear rate of 1000 s ^{-1 was 1.3 Pa · s.}

<Formation of print pattern>
Using the printing plate and the silver ink composition obtained above by the gravure offset printing method, printing was performed on one main surface (surface) of a polycarbonate substrate (thickness 0.4 mm), which is shown in FIG. A mesh-like print pattern was formed. More specifically, the silver ink composition was supplied to the surface of the printing plate having grooves, and the excess silver ink composition was removed by a doctor blade to fill the grooves with the silver ink composition. Then, after transferring the filled silver ink composition to the surface of the blanket material of the offset roll, the silver ink composition is transferred to the surface of the substrate carried by the belt conveyor unit. I printed it. As the offset roll, a metal cylinder whose surface was coated with a blanket material made of silicone resin was used.

<Formation of fine silver wire>
Next, the substrate having the printing pattern obtained above is heated at 120 ° C. for 10 minutes and then placed in a humidified atmosphere at a temperature of 120 ° C. and a relative humidity of 90% for 10 minutes to heat (fire) the printing pattern. ) Processed. As described above, by forming metallic silver from the printing pattern (pattern of the silver ink composition), the mesh-like fine silver lines shown in FIG. 7 were formed on the substrate.

[Reference example 1]
_{As shown in Table 2, the plate making data was prepared so that the length L 1 of the} protruding portion forming the constriction of the groove was 1.5 μm instead of 2.0 μm. The printing plate was manufactured in the same way as in the case. That is, in this reference example, in the production of the printing plate, the groove width W ₁ is 5 μm, the groove depth is 1.9 μm, and the length L _{1 of the} protruding portion forming the groove constriction is 1.5 μm. The plate making data was prepared so that the width L _{2 of the} protruding portion was 1.0 μm, respectively, and a printing plate almost exactly as it was obtained.
Then, a printing pattern and silver fine lines were formed by the same method as in the case of Example 1 except that the printing plate was used.

[Comparative Example 1]
As shown in Table 2, the printing plate was manufactured by the same method as in Example 1 except that the plate making data was prepared so as not to form the constriction of the groove.
Then, a printing pattern and silver fine lines were formed by the same method as in the case of Example 1 except that the printing plate was used.

[Reference example 2]
As shown in Table 2, the _{plate making data was prepared so that the groove width W 1} was 4 μm instead of 5 μm and the groove depth was 1.5 μm instead of 1.9 μm. The printing plate was manufactured in the same way as in the case. That is, in this reference example, in the production of the printing plate, the groove width W ₁ is 4 μm, the groove depth is 1.5 μm, and the length L _{1 of the} protruding portion forming the groove constriction is 2.0 μm. The plate making data was prepared so that the width L _{2 of the} protruding portion was 1.0 μm, respectively, and a printing plate almost exactly as it was obtained.
Then, a printing pattern and silver fine lines were formed by the same method as in the case of Example 1 except that the printing plate was used.

[Example 2]
As shown in Table 2, the _{protrusions further forming a groove constriction so that the groove width W 1} is 4 μm instead of 5 μm and the groove depth is 1.5 μm instead of 1.9 μm, respectively. A printing plate was manufactured by the same method as in Example 1 except that the plate making data was prepared so that the length L _{1 of the portion was 1.5 μm instead of 2.0 μm.} That is, in this embodiment, in the production of the printing plate, the groove width W ₁ is 4 μm, the groove depth is 1.5 μm, and the length L _{1 of the} protruding portion forming the groove constriction is 1.5 μm. The plate making data was prepared so that the width L _{2 of the} protruding portion was 1.0 μm, respectively, and a printing plate almost exactly as it was obtained.
Then, a printing pattern and silver fine lines were formed by the same method as in the case of Example 1 except that the printing plate was used.

[Comparative Example 2]
As shown in Table 2, printing was performed in the same manner as in Example 1 except that the plate making data was prepared so that the groove constriction was not formed and the groove width W _{1 was 4 μm instead of 5 μm.} Manufactured the plate.
Then, a printing pattern and silver fine lines were formed by the same method as in the case of Example 1 except that the printing plate was used.

<< Evaluation of print pattern (fine silver line) >>
<Effect of suppressing expansion of width at the bent part of thin silver wire>
Using a laser microscope (“VK-X100” manufactured by KEYENCE CORPORATION), the fine silver wires of each of the above Examples, Reference Examples and Comparative Examples were observed. Then, the silver fine line, the width D _{L (width} D _L1 and the width D _L2) was measured in all of the bent portion, by measuring the width W _L other than the bent portion to determine the maximum of these measurements. Then, at the bent portion of the silver fine line width D _L1 or width D _L2 is the largest, the effect of suppressing the expansion of the width was evaluated according to the following evaluation criteria from the observation results. The results are shown in Table 2. In Table 2, the description in the column of "expansion suppressing effect" is the corresponding result.
(Evaluation criteria)
A: The effect of suppressing expansion is high.
B: Although it is inferior to A, it has an effect of suppressing expansion.
C: The effect of suppressing expansion is low or not recognized.

<Effect of suppressing the visibility of the bent part of the thin silver wire>
The front surface (back surface) of the substrate provided with the fine silver wire on the side where the fine silver wire is not formed, which is obtained in each of the above Examples, Reference Examples, and Comparative Examples, contains a polycarbonate / ABS resin alloy as a resin component. The substrate was placed on the black substrate in contact with one surface of the black substrate (thickness 2 mm). In this state, the fine silver wire on the substrate is exposed.
Next, four observers visually observed the substrate in this state from above (in other words, the silver fine wire side), and evaluated the visual suppression effect of the bent portion of the silver fine wire according to the following evaluation criteria. The results are shown in Table 2. In Table 2, the description in the column of "visual suppression effect" is the corresponding result.
(Evaluation criteria)
A: The visual suppression effect is high.
B: Although inferior to A, a visual suppression effect is observed.
C: The visual suppression effect is low or not recognized.

<Shape of bent part of fine silver wire>
At the same time as the evaluation of the above-mentioned "effect of suppressing the expansion of the width at the bent portion of the silver fine wire", the shape of the bent portion of the silver fine wire was observed, and from the viewpoint of the conductivity of the silver fine wire, the shape was abnormal according to the following evaluation criteria. The presence or absence was evaluated. The results are shown in Table 2. In Table 2, the description in the "shape" column is the corresponding result.
(Evaluation criteria)
A: No disconnection or other obvious shape abnormality that causes the fine silver wire to have a significantly large resistance value is not observed.
B: There is a disconnection or other obvious shape abnormality that causes the fine silver wire to have a significantly large resistance value.

As is clear from the above results, in Examples 1 and 2, by forming a constriction in the groove of the printing plate, the effect of suppressing the expansion of the width of the fine silver wire and the effect of suppressing the visibility at the bent portion of the fine silver wire are obtained. , And no obvious shape abnormality was observed. As described above, in Examples 1 and 2, the fine silver wire was completely or almost completely formed in the desired shape. Especially in Example 1, the effect was high. In Examples 1 and 2, at the stage where the pattern of the silver ink composition is formed before the pattern of the silver fine lines is formed, the width of the fine lines is sufficiently expanded at the bent portion of the fine lines formed by the composition. It is presumed that it was suppressed.

On the other hand, in Comparative Examples 1 and 2, no constriction was formed in the groove of the printing plate (using the conventional printing plate), so that a clear shape abnormality was observed in the bent portion of the silver fine wire. Although it was not found, the effect of suppressing the expansion of the width of the fine silver wire and the effect of suppressing the visibility were not observed. As described above, in Comparative Examples 1 and 2, the fine silver wire was not formed in the desired shape. It is clear that in Comparative Examples 1 and 2, unlike the cases of Examples 1 and 2, the expansion of the width of the thin line was not suppressed at the bent portion of the thin line formed of the silver ink composition. ..

On the other hand, in the reference example 1, but was formed a constriction in the groove of the plate, the width W ₁ of the groove, (too short length L ₁ of the projecting portion) degree is too small constricted, silver fine line Both the effect of suppressing the expansion of the width and the effect of suppressing the visibility were low. In Reference Example 1, unlike the cases of Examples 1 and 2, it is presumed that the effect of suppressing the expansion of the width of the thin line was insufficient at the bent portion of the thin line formed of the silver ink composition.

In Reference Example 2, due to the formation of a constriction in the groove of the printing plate, the effect of suppressing the expansion of the width of the fine silver wire and the effect of suppressing the visual recognition were observed at the bent portion of the fine silver wire, but the shape was clear. Abnormality was found. More specifically, at the bent portion of the fine silver wire, there was a portion where the volume of the fine silver wire was extremely small and the wire was almost broken. It is presumed that this is because the degree of constriction is too large for _{the width W 1 of the groove (the length L 1 of the} protruding portion is too long). In Reference Example 2, it is presumed that at the bent portion of the thin wire formed of the silver ink composition, there was already a portion where the volume of the layer of the silver ink composition was extremely small.

The present invention can be used when forming a printing pattern using an intaglio plate as a printing plate. For example, a printing technique is used by using a metal ink composition in which a metal forming material is blended and the printing plate. It is suitable for forming fine metal wires. A wiring board provided with such a thin metal wire on a substrate is useful as a member in various electronic devices such as a touch panel and an electromagnetic wave shield, and the present invention is suitable for application at the time of manufacturing these members.

1, 2, 3, 4 ... Printing plate (intaglio), 1a, 2a, 3a, 4a ... Printing plate surface, 8, 9 ... Grooves, 80, 90, 90'... Grooves Bending part, 81, 91, 911, 912, 913, 914 ... Groove constriction (protruding part), θ, θ ₁ , θ ₂ , θ ₃ , θ ₄ ... Bending angle of the groove bending part

Claims (3)

It is a method of forming a printing pattern using an intaglio as a printing plate.
The printing plate has a groove on its surface for filling ink.
The groove has a bent portion that bends in a direction parallel to the surface of the printing plate.
The groove on the side at an angle of less than 180 ° of the bent portion, have a constriction,
When the surface of the printing plate having the groove is viewed in a plan view from above, the constriction is formed inside the groove from the side forming an angle of less than 180 ° of the bent portion to the opposite side. A polyhedral projecting portion is formed and configured so as not to block the groove.
Wherein the length of the projecting portion and L _1, the width of the projecting portion and L _2, in the surface of the printing plate, when the width of the opening other than the bent portion of the groove was set to W _1, L _A method for forming a print pattern, wherein the value of 1 × L ₂ / W ₁ is 0.35 to 0.46 μm. The L ₁ Is 1 to 3 μm, and the above L ₂ Is 0.5 to 2 μm, and the W ₁ The method for forming a print pattern according to claim 1, wherein the size is 1 to 20 μm. The method for forming a print pattern according to claim 1 or 2, wherein the shape of the protruding portion is prismatic.

Images