JP2001260218A - Microembossed plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microembossed plate, with which reduction of the number of times for washing and enhancement of durability can be achieved. SOLUTION: In the microembossed plate 10 for producing a resin sheet, in which microembossing work is performed on the surface, minute unevennesses 10A are formed on a transfer face 11A made of a metal and gold plating is performed on the surfaces of the unevennesses 10A and a gold-plated layer 12 is formed. In such a way as this, durability of the transfer face 11A of the microembossed plate 10 is enhanced by forming the gold-plated layer 12 on the surface of the microembossed plate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-embossing plate, for example, a micro-embossing plate (roll) for forming a Fresnel lens sheet, a lenticular lens sheet, a prism sheet, etc., which require surface smoothness transfer and precise fine transfer. Can be used as

[0002]

BACKGROUND ART In recent years, in the production of sheets such as Fresnel lens sheets, lenticular lens sheets, and prism sheets that require surface smoothness transfer and precise fine transfer, continuous production is possible because the transfer efficiency of micro-embossed plates has been improved. It is becoming.

[0003]

However, since a resin sheet is used as a non-transferred material, when the same micro-embossing plate is used for a long period of time, the bleed resin component adheres, and the attached resin component deteriorates.
There is a problem that the embossing plate needs to be washed or replaced. In addition, there is also a problem that the embossed surface of the micro embossed plate itself deteriorates due to long-term use, so that frequent cleaning of the embossed surface and replacement of the embossed plate are required.

[0004] As a method for solving the above-mentioned problems, there is a method in which hard chrome plating is applied to the surface of a micro-emboss plate. However, when using this method, it is difficult to uniformly plate hard chromium with a thickness of 5 μm or less. Therefore, even if the surface of the micro-embossing plate is unevenly processed with high precision, there is a problem that the desired optical characteristics cannot be obtained because each uneven surface is filled by chromium plating and the sharp corners of the fine unevenness are rounded. . In addition, compared to the case where hard chrome plating is not performed, although a significant improvement effect is seen, in terms of durability, the number of times of cleaning, etc., it is not a method that can be sufficiently satisfied, so a further improvement method is required. I have.

It is an object of the present invention to provide a micro-embossing plate capable of reducing the number of times of cleaning and improving durability.

[0006]

A micro-embossing plate according to the present invention is a micro-embossing plate for producing a resin sheet having a micro-embossed surface, and a micro-embossing plate is provided with a metal transfer surface. It is characterized in that irregularities are formed and the surface of the irregularities is plated with gold. The fine unevenness in the present invention means several μm to several hundred μm.
Means irregularities. An arbitrary shape can be adopted as the shape of the fine unevenness. For example, a cube corner type triangular pyramid diamond cut pattern or the like can be adopted. Further, it is preferable to use electroformed nickel or steel as the metal forming the transfer surface of the micro embossing plate.

In the present invention, as a method of applying gold plating to the transfer surface, a method using a cyan bath based on gold cyanide complex and alkali cyanide, gold cyanide complex and p
A method using an acidic bath based on a buffer of H3 to 6 and a method using a non-cyanide bath based on gold halide or gold sulfite can be adopted.

According to the present invention, since the transfer surface made of electroformed nickel or steel is plated with gold, the surface of the embossed plate,
That is, the transferability and the durability of the transfer surface can be improved. In other words, the resin sheet that is the material to be transferred hardly adheres,
The releasability is improved, and the number of cleanings caused by contamination of the transfer surface can be significantly reduced as compared with the conventional embossing plate. Further, it is possible to greatly improve the deterioration of the transfer performance due to the stain on the transfer surface, that is, the deterioration of the surface roughness of the embossed product.

This makes it possible to use the same micro-embossing plate repeatedly over a long period of time. In addition, since the transfer surface is cleaned, a cleaning liquid such as an acid and an alkali can be used since the transfer surface is cleaned. Therefore, dirt attached to the transfer surface can be easily removed, and the efficiency of the cleaning operation can be improved.

In the above, it is preferable that the thickness of the plating layer of the gold plating applied to the uneven surface is 0.05 to 10.00 μm. Here, the thickness of the plating layer is 0.05
If it is less than μm, the durability of the plating layer may be reduced. On the other hand, if the thickness of the plating layer exceeds 10.00 μm, the sharp corners of the fine irregularities are rounded, and the amount of gold used increases, leading to an increase in the production cost of the embossing plate. . Considering this,
More preferably, the thickness of the plating layer is 0.50 to 1.00 μm.
m.

According to this, 0.05 to 10.00 μm
Since the thickness of the gold plating layer is maintained within the range, the durability of the plating layer can be improved and the shape of the surface of the embossed plate before plating can be maintained. Also, the surface smoothness of the plating layer can be ensured. The micro embossing plate in the present invention is a concept including a micro embossing roll obtained by processing a flat embossing plate into a roll.

The micro-embossing plate described above is a micro-embossing plate (roll) for producing a lens functional sheet such as a Fresnel lens sheet, a lenticular lens sheet, a prism sheet, etc., which require surface smoothness transfer and precise fine transfer. Can be suitably used.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIGS. 1 and 2 show a micro embossing plate 10 according to a first embodiment of the present invention.
The micro embossing plate 10 includes an electroformed nickel plate 11 having a transfer surface 11A on which fine irregularities are formed, and a gold plating layer 12 provided on the irregular surface.

The electroformed nickel plate 11 has a cube corner type micro embossed pattern 10 as fine unevenness.
The replica (not shown) to which A has been applied is nickel-plated by electroforming (electroforming) to obtain a replica mold, and a cube corner type micro emboss pattern 10A corresponding to the prototype is provided. Formed on the surface.
On the other hand, the gold plating layer 12 is formed on the transfer surface 11A of the electroformed nickel plate 11 by a known method, and has a thickness of 0.05 to 10.00 μm.

Next, an apparatus for manufacturing a retroreflective sheet using the above-described micro embossing plate 10 and a method for manufacturing the same will be described with reference to FIG. The manufacturing apparatus 2 includes a flat plate 22 and a heating roll 23 disposed above the flat plate 22 with a gap.

The flat plate 22 is placed on a plurality of feed rollers 24. On the other hand, the heating roll 23 is connected to driving means such as a motor, and is configured to rotate in synchronization with the moving speed of the flat plate 22. In the gap between the flat plate 22 and the space between the heating rolls 23, the above-described micro embossing plate 1 is provided.
0 and a polypropylene sheet 26 as a resin sheet
A predetermined width is set so that the laminate 27 made of (hereinafter, referred to as a PP sheet) can be uniformly pressed over the entire surface.

The manufacture of the retroreflective sheet 20 using the manufacturing apparatus 2 configured as described above is performed as follows. First, a laminate 27 including the micro-embossing plate 10 and the PP sheet 26 is inserted into a wedge-shaped portion 28 between the rotating heating roll 23 and the flat plate 22 moving in the horizontal direction. At this time, the laminate 27 is inserted so that the PP sheet 26 in the laminate 27 is in close contact with the flat plate 22. Subsequently, the heating roll 23 and the flat plate 22 are moved to perform heating and pressurization on the entire surface of the laminated body 27, and the micro embossed pattern 10 </ b> A of the transfer surface 11 </ b> A is transferred to the PP sheet 26, and the retroreflective sheet 20 is transferred. To manufacture. At this time, the heating temperature and the pressure can be appropriately set according to the sheet thickness and the like. Next, the laminate 27 is removed from the device,
After cooling in the laminated state, the retroreflective sheet 20 is peeled off from the micro embossing plate 10 (see FIG. 4).

According to the above-described first embodiment, the following effects can be obtained. (1) Since the gold plating layer 12 is formed on the surface (transfer surface 11A) of the electroformed nickel 11, the releasability (releasability) and durability of the transfer surface 11A can be improved. That is, the PP sheet 26, which is a resin sheet, hardly adheres, and the transfer surface 1
The number of cleanings caused by the contamination of 1A can be significantly reduced as compared with the conventional embossing plate, and the transfer performance due to the contamination of the transfer surface 11A, that is, the deterioration of the surface roughness of the embossed product can be significantly reduced. Can be improved. This makes it possible to repeatedly use the same micro embossing plate 10 over a long period of time.

(2) Since the gold plating layer 12 is formed, a cleaning liquid such as an acid and an alkali can be used for cleaning the transfer surface 11A.
The dirt attached to A can be easily removed, and the efficiency of the cleaning operation can be improved. (3) Gold plating layer 1 in the range of 0.05 to 10.00 μm
2, the durability of the gold plating layer 12 can be enhanced, and the shape of the transfer surface 11A before plating can be reliably retained and reproduced. Also, the surface smoothness of the gold plating layer 12 can be ensured.

(4) In the manufacturing apparatus 2, the heating roll 2
Since the wedge-shaped portion 28 is formed between the plate 3 and the flat plate 22, and the laminated body 27 is inserted into the wedge-shaped portion 28, air bubbles are mixed between the heating roll 23 and the laminated body 27 or the like. Can be prevented. (5) Since one member for pressing the laminate 27 is the flat plate 22, a sufficient planar pressure contact section can be secured between the rotating heating rolls 23. (6) Since the gap between the heating roll 23 and the flat plate 22 can be adjusted to a predetermined width in accordance with the thickness of the laminate 27, uniform pressure can be applied over the entire surface of the laminate 27.

(7) Since the micro-embossing plate 10 and the PP sheet 26 are cooled and solidified in close contact with each other, when the retro-reflective sheet 20 on which the micro-emboss pattern 10A is transferred is peeled off, the retro-reflective sheet 20 is removed. In addition, it is possible to prevent the micro-emboss pattern 10A from being deformed, and stable production is possible. (8) Since the configuration of the manufacturing apparatus 2 is simple, the apparatus 2 can be obtained at low cost.

[Second Embodiment] FIG. 5 shows an apparatus 3 for manufacturing a retroreflective sheet 20 using a stamper roll 31 in which the micro-embossing plate 10 described in the first embodiment is processed into a roll. ing. The manufacturing apparatus 3 includes a micro emboss roll 30 and a pressure nip roll 38.
, Glazing device 40, heating device 50, shielding plate 60
And a cooling device 70.

The micro-embossing roll 30 includes a stamper roll 31 formed by processing the above-described electric pole nickel plate 11 into a cylindrical shape, and includes a stamper roll 3 therein.
A support roll 32 and a backup roll 35 having an inner diameter smaller than 1 are provided. Further, a cooling box 70 including a heat exchanger is provided between the support roll 32 and the backup roll 35 inside the micro-emboss roll 30.

The support roll 32 is a cooling roll having a hollow inside and a cooling medium flowing into the hollow portion, and is eccentrically disposed in the stamper roll 31. Between these rolls 31 and 32, a contact portion 36A where they are in contact with each other and a gap portion 36B which is separated from each other are formed. By the contact at the contact portion 36A, the stamper roll 31 is brought into contact with the support roll 32. It is made to rotate at the same time. Further, the stamper roll 31 is cooled by the contact portion 36A, so that the retroreflective sheet 20 transferred at this portion is easily peeled off.

The pressure nip roll 38 is a metal roll whose surface is coated with an elastic material 39 made of silicone rubber. The PP sheet 26, which is a resin sheet supplied on the stamper roll 31, is applied to the stamper roll 31. On the other hand, a predetermined pressure is applied. Note that the thickness and hardness of the elastic material 39 to be coated can be appropriately set according to the thickness of the sheet to be used and the like. Glazing device 4
Reference numeral 0 denotes first and second cooling rolls 41 and 42 arranged near the micro embossing roll, and a third cooling roll 43 arranged at a position distant from the micro embossing roll.
And an endless belt 44 wound around each of the rolls 41, 42, 43. here,
A cooling box 70 is also provided at a position along the endless belt 44 between the first and second cooling rolls 41 and 42.

First to third cooling rolls 41, 42, 43
Is a metal roll, in which cooling means such as a water-cooled type is provided (not shown). In addition, the first to third
At least one rotation shaft of the cooling rolls 41, 42, 43 is connected to a rotation driving unit. Note that the third cooling roll 43 may be omitted as appropriate. On the other hand, the endless belt 44 is a belt made of stainless steel, and is set so as to press the surface of the PP sheet 26 opposite to the transfer surface between the first and second cooling rolls 41 and 42 toward the stamper roll 31. ing.

The heating device 50 may be appropriately selected from, for example, a high-frequency induction heater, a halogen heater, an IR heater, a burner heater and the like according to the material and thickness of the sheet to be used. it can. In the present embodiment, the heating device 50 is provided so as to heat the stamper roll 31 from the outside, but is not limited thereto.
Heat may be applied from the inside of the stamper roll 31. The shielding plate 60 is, for example, a metal plate made of aluminum, stainless steel, or the like, or a plate having an insulating effect such as a metal plate having an insulating member attached thereto. The shielding plate 60 is attached along the axial direction of the micro-emboss roll 30. I have.

The manufacture of the retroreflective sheet 20 using the manufacturing apparatus 3 configured as described above is performed as follows. First, the support roll 32 is eccentrically arranged in the stamper roll 31, and in this state, the stamper roll 31 is rotated and the endless belt 44 is rotated. Further, the heating device 50 heats the stamper roll 31 to a predetermined temperature at which transfer can be performed, and circulates a cooling medium inside the support roll 32.

In this state, the PP sheet 26 is supplied onto the stamper roll 31, and the PP sheet 26 is pressed against the surface of the stamper roll 31 by the pressure nip roll 38.
The micro emboss pattern is transferred to the sheet 26.
At this time, due to the elasticity of the elastic material 39 covering the surface of the pressure nip roll 38, the PP sheet 26 is brought into planar pressure contact.

Thereafter, the transferred PP sheet 26 is moved together with the rotation of the stamper roll 31, and the pressure is reduced between the endless belt 44 constituting the glazing device 40 and the stamper roll 31 to cover the PP sheet 26. The surface opposite to the transfer surface is mirror-transferred and glazed to form a retroreflective sheet 20. The retroreflective sheet 20 having both sides transferred in this manner further moves together with the stamper roll 31 to form the support roll 3 serving as a cooling roll.
2 and the lower surface of the contact portion 36A between the stamper roll 31 is cooled, peeled off and wound. Thus, the retroreflective sheet 20 is obtained.

According to the above-described second embodiment, the same effects as (1) to (3) of the first embodiment can be obtained, and also the following effects can be obtained. (9) Since the glazing device 40 is provided, one surface of the PP sheet 26 is embossed, and the other surface is glazed, thereby embossing the surface. Can be provided with optical retroreflection, and a glossy surface can be provided with gloss.

(10) The heating device 50 heats the stamper roll 31 from the outside.
Can be heated more efficiently, the softening of the PP sheet 26 can be promoted, the insufficient filling of the transfer surface of the stamper roll 31 can be prevented, and the transfer can be performed more favorably. (11) Since the heating device 50 is arranged outside,
The structure of the roll 30 is simplified, the processing apparatus can be made more compact, and maintenance is easy. (12) Since the shielding plate 60 is provided, the heating device 5
The heat of 0 can be prevented from adversely affecting the other. In particular, since the temperature rise of the contact portion 36A is suppressed, the retroreflective sheet 20 can be reliably separated.

It should be noted that the present invention is not limited to the above embodiment, and modifications and improvements as long as the object of the present invention can be achieved are included in the present invention. For example, in each of the above embodiments, the micro embossed pattern 10 </ b> A,
Is a cube corner type, but is not limited thereto, and may have various shapes. In addition, although the electroformed nickel plate 11 is employed, the invention is not limited to this. In short, any metal can be used as long as it can form a micro-embossed pattern and can be plated with gold. For example, steel or the like can be used.

In each of the above embodiments, the polypropylene sheet 2 is used as the raw resin sheet of the retroreflective sheet 20.
6, but the invention is not limited to this, and for example, a vinyl chloride, polycarbonate sheet or the like may be adopted. Further, the manufacturing apparatus of the retroreflective sheet 20 provided with the micro-embossing plate 10 is not limited to the manufacturing apparatuses 2 and 3 of each of the above-described embodiments. Other devices can be used. In addition, the specific structure, shape, and the like when implementing the present invention may be other structures within a range that can achieve the object of the present invention.

[0035]

The present invention will be described below in detail with reference to examples and comparative examples. Note that the present invention is not limited to the contents described below. [Example 1] (Micro embossing plate) A gold plating layer 12 having a thickness of 0.5 µm is plated on an electroformed nickel plate 11 having a transfer surface 11A on which a cube corner type micro embossed pattern 10A having a bottom of about 150 µm is formed. Thus, a micro embossed plate 10 was obtained. (Retro-reflective sheet) Using the micro-embossing plate 10 described above, the manufacturing apparatus 3 of the second embodiment embosses a 0.3-mm-thick polypropylene sheet 26 under the following conditions to obtain a retro-reflective sheet. 20 was obtained. Processing temperature: 120 ° C. Processing pressure: 3.92 MPa (actual value: 40 kgf / cm ²⁾
Is converted to SI unit) Peeling temperature: 30 ° C

Example 2 (Micro-embossed plate) A micro-embossed plate 10 was obtained by plating the electroformed nickel plate 11 used in Example 1 with a gold plating layer 12 having a thickness of 10.00 µm. (Retroreflective Sheet) Using the micro-embossing plate 10 described above, a polypropylene sheet 26 having a thickness of 0.3 mm is embossed under the same conditions and under the same manufacturing apparatus as in Example 1 to form a retroreflective sheet 20. Obtained.

[Comparative Example 1] (Micro-embossed plate) The electroformed nickel plate on which the micro-embossed pattern of Example 1 was formed was directly used as a micro-embossed plate without plating. (Retroreflective sheet) Using the micro-embossing plate described above, under the same conditions and the same manufacturing apparatus as in Example 1, a thickness of 0.
A 3 mm polypropylene sheet 26 was embossed to obtain a retroreflective sheet 20.

Comparative Example 2 (Micro-embossed plate) A micro-embossed plate having a thickness of 10.00 μm and subjected to hard chromium plating was used for the electroformed nickel plate used in Example 1. (Retroreflective sheet) Using the micro-embossing plate described above, under the same conditions and the same manufacturing apparatus as in Example 1, a thickness of 0.
A 3 mm polypropylene sheet 26 was embossed to obtain a retroreflective sheet 20.

With respect to the micro-embossed plates of the above Examples and Comparative Examples, the initial luminance and the luminance after transfer of 10,000 m of the retroreflective sheet 20 obtained by embossing were measured, and the results are shown in Table 1. Summarized. Here, the luminance (retroreflection coefficient) of the retroreflective sheet is based on JIS Z 9117.
(Irradiation angle: 5 degrees, observation angle: 0.2 degrees, average value of n = 3).

[0040]

[Table 1]

As shown in Table 1, in Examples 1 and 2, a retroreflective sheet was manufactured using a gold-plated micro-embossed plate. The brightness of the conductive sheet is 1 compared to the initial value.
Only about 0% decreased (Example 1: 200 → 18
0, Example 2: 180 → 160), indicating that the durability of the transfer surface is extremely high. In comparison between Example 1 and Example 2, Example 1 in which the thickness of the gold plating layer is as thin as 0.5 μm reflects the micro-emboss pattern on the transfer surface better, and the obtained retroreflection It can be seen that the brightness of the conductive sheet is high.

On the other hand, in Comparative Example 1 in which an electroformed nickel plate was used as a micro-emboss plate,
The initial luminance of the obtained retroreflective sheet is 200, which is about the same value as in Examples 1 and 2. However, the value is reduced to 5 after the transfer of 10,000 m. It can be seen that the durability is significantly reduced.

In Comparative Example 2 in which a hard chromium plating having a thickness of 10.00 μm was applied to the transfer surface, the thickness of the plating layer was much larger than that in Examples 1 and 2, and It can be seen that the luminance of the resulting retroreflective sheet is reduced to 150. Furthermore, the luminance after transfer of 10,000 m is 45, which is a large decrease from the initial value, and it is understood that the surface durability is inferior to that of the gold plating.

That is, by using gold plating, whose layer thickness can be controlled to be thinner than that of hard chrome plating, it is possible to obtain an initial luminance substantially equal to that obtained when no plating is applied as in the first and second embodiments. Understand. Further, it can be seen that the durability of the transfer surface is improved by applying the gold plating, and a retroreflective sheet having sufficient luminance can be obtained even after the transfer of 10,000 m.

[0045]

According to the present invention, since the transfer surface made of electroformed nickel or steel is plated with gold, the durability of the transfer surface can be improved. In other words, the resin sheet, which is the material to be transferred, is less likely to adhere, and the number of times of cleaning associated with transfer surface dirt can be significantly reduced as compared with the conventional embossing plate. That is, there is an effect that deterioration of the surface roughness of the embossed product can be significantly improved.

Thus, over a long period of time,
It is possible to use the same micro-embossed plate.
In addition, since the transfer surface is cleaned by using gold, a cleaning solution such as an acid and an alkali can be used when cleaning the transfer surface. Therefore, dirt attached to the transfer surface can be easily removed, and the efficiency of the cleaning operation can be improved. There is an effect that it can be achieved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a micro embossing plate according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in the embodiment of FIG.

FIG. 3 is a schematic diagram showing a sheet manufacturing apparatus according to the embodiment of FIG.

FIG. 4 is a diagram showing a state in which the micro-embossing plate and the sheet according to the embodiment of FIG. 1 are peeled off.

FIG. 5 is a schematic view showing a sheet manufacturing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Micro embossing plate 10A Micro emboss pattern which is uneven 11 Electroformed nickel plate as metal plate 11A Transfer surface 12 Gold plating layer 20 Retroreflective sheet 26 PP sheet as resin sheet

Claims (3)

[Claims] 1. A micro-embossing plate for producing a resin sheet having a micro-embossed surface, wherein fine irregularities are formed on a metal transfer surface, and gold plating is formed on the irregular surface. A micro-embossed version characterized by being applied. 2. The micro-embossed plate according to claim 1, wherein the gold plating has a thickness of 0.05 to 1 mm.
A micro-embossed plate having a thickness of 0.00 μm. 3. The micro-embossed printing plate according to claim 1, wherein the transfer surface is made of electroformed nickel or steel.