JP2016141069A - Method for producing decorative sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily producing a decorative film which hardly forms an air layer even if stuck to an image display surface without using a large-scale facility or device.SOLUTION: There is provided a method for producing a decorative film for protecting an image display surface, which comprises: a printing step of screen printing a transparent curable resin having a viscosity of 0.2 to 1.0 Pa s on a surface of a transparent base material film in which a decorative layer is formed in a part of the surface; after the printing step, a still standing step of leaving the base material film on which the curable resin is printed; and after the still standing step; a curing step of curing the curable resin printed on the surface of the base material film, where in the printing step, the curable resin is screen printed so that a part in which the decorative layer is not formed of the surface of the base material film is filled with the curable resin using a printing plate equipped with a plate frame and two or more gauzes overlapped and stretched inside the plate frame.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a decorative film.

Transparent on the surface (image display surface) of image display devices (eg, display windows for TVs, notebook computers, tablets, smartphones, mobile phones, digital signage, monitors, cameras, etc.) for the purpose of protection and design A decorative film in which a decorative layer (printing layer) is formed on a part of the surface of a simple base film may be attached.
However, on the surface (decorative layer forming surface) on which the decorative layer of the base film is formed, a portion where the decorative layer is formed (decorative portion) and a portion where the decorative layer is not formed ( Since there is a non-decorative part), the thickness of the decorative film is not uniform. When the decorative film is attached to the image display surface, the decorative layer side becomes the image display surface side. Therefore, when the decorative film is attached to the image display surface, the decorative layer serves as a spacer, and the image display A gap is generated between the surface and the decorative film. Since an air layer is formed in the gap, an image displayed due to light scattering or the like is obscured, or visibility is easily lowered.

Therefore, a decorative film having a uniform thickness has been proposed.
For example, in Patent Documents 1 to 3, the curable resin is screen-printed on the decorative layer forming surface of the base film to fill the non-decorated portion with the curable resin, and the curable resin is cured. A method for producing a decorative film having a uniform thickness is disclosed.

JP 2012-230304 A JP 2012-22281 A JP 2014-119547 A

However, in the case of the methods described in Patent Documents 1 to 3, in order to make the thickness of the decorative film uniform, before the curable resin is cured, the separator film is placed on the printing surface on which the curable resin is screen-printed. However, it was necessary to press the printing surface with a nip roll to smooth the surface. For this reason, there are problems such as taking time and effort, and requiring large facilities and equipment.
Moreover, since the curable resin is cured in a state where the separator film is laminated after the printing surface is smoothed, the separator film remains in the obtained decorative film. For this reason, in order to attach the decorative film to the image display surface, it is necessary to remove the separator film from the decorative film and then provide an adhesive layer, a double-sided tape, etc. on the printing surface, which takes time and effort. It was.

  The present invention has been made in view of the above circumstances, and a method for easily producing a decorative film in which an air layer is hardly formed even if it is attached to an image display surface, without using large-scale equipment and devices. provide.

The present invention has the following aspects.
[1] A method for producing a decorative film for protecting an image display surface, wherein a viscosity of 0.2 to 1.0 Pa is applied to the surface of a transparent base film in which a decorative layer is formed on a part of the surface. A printing step of screen-printing a transparent curable resin of s, a stationary step of standing a base film on which the curable resin is printed after the printing step, and the base film after the stationary step A curing step for curing the curable resin printed on the surface of the printing plate, and in the printing step, a printing plate comprising a plate frame and a ridge stretched over two or more sheets inside the plate frame A method for producing a decorative film, in which a curable resin is screen-printed so that a portion of the surface of the base film where the decorative layer is not formed is filled with the curable resin.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing simply the decorative film in which an air layer is hard to be formed even if it affixes on an image display surface can be provided, without using a large installation and apparatus.

It is sectional drawing which illustrates the manufacturing process of a decorating film typically. It is sectional drawing which shows an example of the printing plate used for this invention.

Hereinafter, an example of the manufacturing method of the decorative film of this invention is demonstrated.
The manufacturing method of the decorative film of this invention has a printing process demonstrated below, a stationary process, and a hardening process.
In the present invention, “transparent” means transmitting at least light having a wavelength of 400 to 760 nm.

<Printing process>
The printing step is a step of screen-printing a transparent curable resin having a viscosity of 0.2 to 1.0 Pa · s on the surface of the transparent base film having a decorative layer formed on a part of the surface. .

(Base film)
For example, as shown in FIG. 1A, the base film to be printed has a decorative layer 12 formed on a part of the surface of the base film 11.
Hereinafter, in the surface of the base film 11, a portion 13 where the decorative layer 12 is formed is referred to as a “decorative portion”, and a portion 14 where the decorative layer 12 is not formed is referred to as a “non-decorative portion”. Further, the surface on which the decorative layer 12 is formed is referred to as “the surface of the base film”, and the surface on which the decorative layer 12 is not formed is referred to as “the back surface of the base film”.

The material of the base film 11 is not particularly limited as long as it is transparent. For example, polyester resin (polyethylene terephthalate, polybutylene phthalate, etc.), polycarbonate resin, acrylic resin, polystyrene resin, vinyl chloride resin, cellulose resin ( Triacetyl cellulose, etc.), polyurethane resins, polyolefin resins, polyamides and the like.
The thickness of the base film 11 is not particularly limited, but is usually about 0.050 to 3.0 mm.

On the periphery of the surface of the base film 11 of this example, a decorative layer 12 having a three-layer structure including a first decorative layer 12a, a second decorative layer 12b, and a third decorative layer 12c. Is formed.
The thicknesses of the first decorative layer 12a, the second decorative layer 12b, and the third decorative layer 12c are not particularly limited, but the total thickness is preferably 30 μm or less.

The first decorative layer 12a, the second decorative layer 12b, and the third decorative layer 12c are each formed by screen-printing a paint on the surface of the base film 11 or the like. As the paint, known paints used for the decorative layer can be used.
The second decorative layer 12b and the third decorative layer 12c are mainly formed for the purpose of preventing see-through (concealment). In this example, the see-through preventing layers are two layers of the second decorative layer 12b and the third decorative layer 12c, but are not limited to two layers, and may be one layer or three or more layers. The number of see-through preventing layers tends to be smaller as the color of the first decorative layer 12a is darker and larger as the color becomes thinner. Further, when the first decorative layer 12a is black, it is not always necessary to provide a layer for preventing see-through.

(Curable resin)
The curable resin used in the printing process is not particularly limited as long as it is transparent, and examples thereof include a photocurable resin and a thermosetting resin. Among these, a photocurable resin is preferable in that the base film 11 is not easily deformed by heat.

Examples of the photocurable resin include polyacryl (meth) acrylate, polyurethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, and polyol (meth) acrylate. These photocurable resins may be used alone or in combination of two or more. Moreover, you may use together these photocurable resins and a photoinitiator as needed.
Examples of the thermosetting resin include epoxy resins, phenol resins, urethane resins, alkyd resins, bismaleimide resins, unsaturated polyester resins, vinyl ester resins, urea resins, melamine resins, maleimide resins, and polyimides. These thermosetting resins may be used alone or in combination of two or more. Moreover, you may use together these thermosetting resins and a thermal-polymerization initiator as needed.
These curable resins may contain a curing agent, a curing accelerator, a binder, a surface conditioner, a plasticizer, an ultraviolet absorber, a light stabilizer, and the like as necessary.

The viscosity of the curable resin is 0.2 to 1.0 Pa · s. The viscosity of the curable resin is preferably 0.3 Pa · s or more, and more preferably 0.5 Pa · s or more. Further, the viscosity of the curable resin is preferably 0.8 Pa · s or less, and more preferably 0.7 Pa · s or less. When the viscosity of the curable resin is less than 0.2 Pa · s, the curable resin leaks from the wrinkles of the printing plate (ink dripping) when the printing plate described later is filled. On the other hand, when the viscosity of the curable resin is more than 1.0 Pa · s, the curable resin becomes difficult to be pushed out from a printing plate described later, and screen printing becomes difficult. Even if the curable resin is printed, the boundary portion 12d between the base film 11 and the first decorative layer 12a, the boundary portion 12e between the first decorative layer 12a and the second decorative layer 12b, the first It becomes difficult to fill the curable resin up to the boundary portion 12f between the second decorative layer 12b and the third decorative layer 12c (hereinafter, these boundary portions are collectively referred to as “the corners of the steps”). In addition, even if the stationary process mentioned later is performed, a printing surface becomes difficult to become smooth.
The viscosity of the curable resin is a value measured with an ultrasonic viscometer at a measurement temperature of 20 ° C.

(Printed version)
As shown in FIG. 2, for example, the printing plate used in the printing process includes a plate frame 15a and two or more ridges (mesh) 15b stretched over the inside of the plate frame 15a.
Even though two or more ridges 15b constituting the printing plate 15 are overlapped, the same effect as the high mesh can be obtained (that is, the eyes can be made fine), but without reducing the permeation amount of the curable resin. It is possible to screen-print a curable resin having a low viscosity (specifically, 1.0 Pa · s or less).
As the number of the ridges 15b increases, screen printing using a curable resin of 1.0 Pa · s or less becomes easier. However, as the number of sheets increases, the printing speed decreases and productivity tends to decrease. Therefore, the number of the ridges 15b is preferably 2 to 5, and more preferably 2 to 3.

The plate frame 15a is not particularly limited, and an existing one can be used. The size of the plate frame 15 a is determined according to the size of the base film 11.
There is no particular limitation on the bag 15b, and an existing one can be used. An example is shown below.
Examples of the material of the collar 15b include polyester, nylon, polyethylene, and stainless steel.
The collar 15b is subjected to exposure and development processing, and a pattern (not shown) corresponding to the size of the non-decorative portion 14 is formed.

Note that the printing plate 15 may be provided with the same type of ridges 15b, or may be provided with different types of ridges 15b. When different types of 15b are provided, the mesh number of the ridges 15b on the printing surface side (the substrate film 11 side to be screen printed) is larger than the mesh number of the ridges 15b on the coating surface side (squeegee 17 side). A configuration is preferable, and a configuration in which a high mesh is provided on the printing surface side and a low mesh is provided on the coating surface side is more preferable. When the number of the ridges 15b is three or more, it is more preferable to reduce the number of meshes of the ridges 15b stepwise from the printing surface side to the coating surface side.
As the number of meshes of the ridges 15b increases, the crease eyes become finer, which is advantageous in that the occurrence of crease eyes after printing (that is, the surface of the base film 11 is marked with crease eyes) is suppressed. The overall discharge amount is reduced. Therefore, the ridge 15b having a large number of meshes is effective when the decorative layer 12 formed on the surface of the base film 11 is thin, but when the decorative layer is thick, the discharge amount tends to be insufficient. On the other hand, the smaller the number of meshes of the ridges 15b, the more the discharge amount can be secured. Therefore, the ridge 15b having a small number of meshes is not suitable for printing ink with high fluidity.
By adopting a configuration in which the above-described high mesh and low mesh are used in combination, it is easy to adjust the ink discharge amount while suppressing the generation of wrinkles.
The mesh number of the ridges 15b on the printing surface side is preferably 200 or more per inch. On the other hand, the number of meshes of the ridges 15b on the coated surface side is preferably 400 or less per inch. However, the number of meshes of the ridges 15b on the printing surface side is greater than the number of meshes of the ridges 15b on the coating surface side.

(Screen printing)
Screen printing is performed as follows.
First, as shown in FIG.1 (b), the printing plate 15 is installed on this surface of the base film 11 in which the decoration layer 12 was formed in a part of surface.
Next, the curable resin 16 is placed on the printing plate 15 and the squeegee 17 is slid. Then, as shown in FIG.1 (c), the curable resin 16 extruded by the squeegee 17 flows into the non-decoration part of the base film 11, and as shown to FIG. A curable resin 16 is filled. In the non-decorated portion, the curable resin 16 is preferably filled at least up to the height of the decorative layer 12.

In the illustrated example, the curable resin 16 is printed only on the non-decorated portion of the base film 11, but the curable resin may also be printed on the third decorative layer 12c.
In the illustrated example, the boundary portion 12d between the base film 11 and the first decorative layer 12a, the boundary portion 12e between the first decorative layer 12a and the second decorative layer 12b, and the second decorative layer. The curable resin 16 is spread all over the boundary portion 12f between the 12b and the third decorative layer 12c, but if the curable resin 16 is spread over at least the boundary portion 12d, the boundary portion 12e and the boundary portion 12f The curable resin 16 may not be spread. This is because when the decorative film is attached to the image display surface, the boundary portion 12e and the boundary portion 12f become blind spots of the first decorative layer 12a, and thus the curable resin 16 is not spread over these portions. This is because the visibility is hardly affected. However, if the curable resin 16 having a viscosity of 0.1 to 1.0 Pa · s is used, the curable resin is easily spread to the corners of the steps.

<Standing process>
A stationary process is a process of leaving the base film with which curable resin was printed after a printing process.
As shown in FIG. 1E, the curable resin printed on the base film 11 is removed by removing the printing plate from the base film 11 and leaving the base film 11 on which the curable resin 16 is printed. 16 surfaces (hereinafter referred to as “printing surfaces”) are smoothed (leveled).
The standing time is preferably 5 minutes or more, more preferably 15 minutes or more, further preferably 30 minutes or more, and particularly preferably 60 minutes or more. If the standing time is 5 minutes or more, the printed surface is sufficiently smoothed. The upper limit of the standing time is not particularly limited, but the smoothing effect reaches its peak even if it exceeds 24 hours. Therefore, 24 hours is sufficient.

<Curing process>
The curing step is a step of curing the curable resin printed on the surface of the base film after the standing step.
The method for curing the curable resin is not particularly limited, and may be determined according to the type of the curable resin.
For example, when a photocurable resin is used as the curable resin, the curable resin is irradiated with active energy rays such as ultraviolet rays, visible rays, electron beams, plasma, and heat rays (infrared rays and the like). The integrated light amount of the active energy ray is preferably 400 to 2000 mJ / cm ² .
When a thermosetting resin is used as the curable resin, the curable resin is cured by heat treatment. The curing temperature is preferably 60 to 150 ° C.
Moreover, you may use the method of heat-processing curable resin and irradiating an active energy ray after that and hardening | curing curable resin.

<Decorative film>
By passing through the printing process, the stationary process, and the curing process, for example, as shown in FIG. 1 (f), the curable resin cured product (curable resin layer) 18 is formed in the non-decorated portion. The decorative film 10 is obtained. In the non-decorative portion, the curable resin layer 18 is preferably formed up to at least the height of the decorative layer 12.

<Effect>
Generally, the viscosity of a paint used for screen printing is as high as about 4 to 10 Pa · s. Therefore, even if a curable resin having a high viscosity is screen-printed on the surface on which the decorative layer of the base film is formed, it is difficult to sufficiently spread the curable resin to the corners of the steps.
If a curable resin having a low viscosity is used, the curable resin can easily reach the corners of the steps. However, a curable resin having a low viscosity is liable to leak (ink dripping) from the wrinkles of the printing plate and is not suitable for screen printing.
Therefore, in the present invention, it is possible to perform screen printing using a low-viscosity curable resin by using a curable resin having a viscosity of 0.2 to 1.0 Pa · s and stacking two or more wrinkles. .

  Moreover, since a low-viscosity curable resin is used in the printing process, the printing surface is smoothed only by leaving the substrate film on which the curable resin is printed in the stationary process. Therefore, it is not necessary to smooth the surface with a nip roll as described in Patent Documents 1 to 3, and a separator film used for smoothing is not used. For this reason, it is difficult to produce a decorative film, and the decorative film can be easily manufactured. Moreover, the equipment and apparatus used for the production of the decorative film are less likely to be large-scale.

Furthermore, as above-mentioned, in order to stick the decorating film manufactured by the method described in patent documents 1-3 on an image display surface, after peeling a separator film from a decorating film, it is an adhesive on a printing surface. Since layers and double-sided tape were provided, it took time and effort.
However, since the separator film is not used in the method for producing a decorative film of the present invention, there is no need to peel it off, and an adhesive layer or a double-sided tape can be provided on the printing surface as soon as the decorative film is produced. . Furthermore, in the case of a conventional decorative film, the peeled separator film is discarded, but since the separator film is not used in the decorative film obtained according to the present invention, waste can be reduced.

  The decorative film obtained by this invention has the curable resin layer formed in the non-decorative part. Therefore, when pasted on the image display surface, compared with the case where the curable resin layer is not formed on the non-decorative portion, it is difficult to form a gap between the decorative film and the image display surface, and the air layer Hard to form. In particular, when the curable resin layer is formed at least up to the height of the decorative layer in the non-decorated portion, the thickness of the decorative film becomes more uniform. A gap is less likely to be formed between the decorative film and the image display surface, and an air layer is less likely to be formed. Therefore, the image is clear and the deterioration of visibility can be suppressed.

<Application>
The decorative film obtained by the present invention is used for protecting the image display surface. Specifically, it is attached to the surface (image display surface) of an image display device (for example, a display window such as a television, a notebook computer, a tablet, a smartphone, a mobile phone, a digital signage, a monitor, or a camera).

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

"Example 1"
As a base film, a first decorative layer 12a (thickness 7 μm) and a second decorative layer 12b (as shown in FIG. A layer in which a decorative layer 12 having a three-layer structure including a thickness 5 μm) and a third decorative layer 12 c (thickness 5 μm) was used was used.
Further, as the printing plate, as shown in FIG. 2, a printing plate having a square plate frame 15a having an outer dimension of 750 mm × 750 mm and two ridges 15b stretched on the inside of the plate frame 15a. Using. As the ridges 15b, 400 meshes per inch and 200 meshes are used, and the number of meshes of the ridges 15b on the printing surface side is larger than the number of meshes of the ridges 15b on the coat surface side. Two ridges 15b were provided.
In addition, a photocurable resin having a viscosity of 0.7 Pa · s was used as the curable resin. The viscosity of the curable resin was measured with an ultrasonic viscometer at a measurement temperature of 20 ° C.

First, as shown in FIG.1 (b), the printing plate 15 was installed on this surface of the base film 11 in which the decoration layer 12 was formed in a part of surface. Next, the curable resin 16 is placed on the printing plate 15, the squeegee 17 is slid, and as shown in FIG. 1 (c), the curable resin 16 is extruded by the squeegee 17, and as shown in FIG. 1 (d), The non-decorated portion was filled with the curable resin 16 up to the height of the decorative layer 12 (printing process).
Next, the base film on which the curable resin was printed was allowed to stand for 30 minutes (a standing step). When the printed surface after standing was observed with the naked eye, the surface was smoothed.
Next, using an ultraviolet irradiator, the curable resin printed on the surface of the substrate film was cured by irradiating the substrate film with ultraviolet rays at an integrated light quantity of 1000 mJ / cm ² (curing step), and FIG. The decorative film 10 in which the curable resin layer 18 was formed to the height of the decoration layer 12 in the non-decoration part was obtained.
When the obtained decorative film 10 was confirmed visually, the curable resin layer 18 was formed to the corner of the step.

Double-sided tape was affixed to the surface of the obtained decorative film 10 on the side of the decorative layer 12 and the curable resin layer 18, and the decorative film 10 was attached to a glass plate via the double-sided tape.
When the glass plate was visually confirmed from the decorative film 10 side, the air layer was not formed between the glass plate and the decorative film 10, and visibility was favorable.

"Example 2"
A decorative film was produced in the same manner as in Example 1 except that a photocurable resin having a viscosity of 0.2 Pa · s was used as the curable resin, and visibility was confirmed.
As a result, the obtained decorative film had a curable resin layer formed up to the corner of the step. Moreover, when the glass plate was visually confirmed from the decorative film side, the air layer was not formed between the glass plate and the decorative film, and visibility was favorable.

"Example 3"
A decorative film was produced in the same manner as in Example 1 except that a photocurable resin having a viscosity of 0.9 Pa · s was used as the curable resin, and visibility was confirmed.
As a result, the obtained decorative film had a curable resin layer formed up to the corner of the step. Moreover, when the glass plate was visually confirmed from the decorative film side, the air layer was not formed between the glass plate and the decorative film, and visibility was favorable.

Example 4
A decorative film was produced in the same manner as in Example 1 except that a printing plate in which the number of ridges was changed to 3 was used, and the visibility was confirmed. As the ridges 15b, 400 meshes per inch, 270 meshes, and 150 meshes are used, and the number of meshes of the ridges 15b is gradually reduced from the printing surface side to the coating surface side. As shown, three ridges 15b were provided.
As a result, the obtained decorative film had a curable resin layer formed up to the corner of the step. Moreover, when the glass plate was visually confirmed from the decorative film side, the air layer was not formed between the glass plate and the decorative film, and visibility was favorable.

"Comparative Example 1"
An attempt was made to produce a decorative film in the same manner as in Example 1 except that a photocurable resin having a viscosity of 0.1 Pa · s was used as the curable resin. The liquid leaked (ink dripping), and the curable resin could not be screen printed.

"Comparative Example 2"
A decorative film was produced in the same manner as in Example 1 except that a photocurable resin having a viscosity of 1.15 Pa · s was used as the curable resin, and visibility was confirmed.
As a result, in the obtained decorative film, the curable resin layer was not formed up to the corner of the step. In addition, the printed surface is not sufficiently smooth, and when the glass plate is visually confirmed from the decorative film side, a gap is formed between the glass plate and the decorative film, and an air layer is formed. It was.
Therefore, when the obtained decorative film was stuck on a glass plate, the visibility was lowered.

“Comparative Example 3”
An attempt was made to produce a decorative film in the same manner as in Example 1 except that the printing plate in which the number of wrinkles was changed to 1 was used, but the curable resin leaked (inked) from the wrinkles of the printing plate. The curable resin could not be screen printed. As the ridges 15b, 400 meshes per inch were used.

“Comparative Example 4”
A decorative film was produced in the same manner as in Example 1 except that the curing process was performed immediately after the printing process without performing the stationary process, and the visibility was confirmed.
As a result, the printed surface is not sufficiently smooth, and when the glass plate is visually confirmed from the decorative film side, a gap is formed between the glass plate and the decorative film, and an air layer is formed. It had been.
Therefore, when the obtained decorative film was stuck on a glass plate, the visibility was lowered.

DESCRIPTION OF SYMBOLS 10 Decorative film 11 Base film 12 Decorative layer 12a First decorative layer 12b Second decorative layer 12c Third decorative layer 12d Boundary part 12e Boundary part 12f Boundary part 13 Decorative layer is formed Part (decoration part)
14 The part where the decoration layer is not formed (non-decoration part)
15 Printing plate 15a Plate frame 15b メ ッ シ ュ (mesh)
16 curable resin 17 squeegee 18 cured product of curable resin (curable resin layer)

Claims (1)

A method for producing a decorative film for protecting an image display surface,
A printing step of screen-printing a transparent curable resin having a viscosity of 0.2 to 1.0 Pa · s on the surface of the transparent substrate film having a decorative layer formed on a part of the surface;
After the printing process, a stationary process of standing the base film on which the curable resin is printed,
A curing step of curing the curable resin printed on the surface of the base film after the stationary step;
In the printing step, a printing plate provided with a plate frame and a ridge stretched over two or more sheets inside the plate frame is used, and a decorative layer is not formed on the surface of the base film. A method for producing a decorative film, in which a curable resin is screen-printed so that a portion is filled with a curable resin.

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