JPH08252985A - Cover film - Google Patents

Abstract

PURPOSE: To improve preservability of images without damaging image quality by forming, on the images, a transparent film which contains a specified compound having a methyl methacrylate unit and a 2-hydroxy 4-(methacryloyloxyethoxy)benzophenone unit. CONSTITUTION: For a composing compound of a transparent film to be formed on images of protecting the images, a compound shown in a formula is used. The compound in the formula is of a copolymer of a methyl methacrylate and a 2-hydroxy 4-]methacryloyloxyethoxy)benzophenone. Regarding the ratio between the methyl methacrylate unit and the 2-hydroxy 4-(methacryloyloxyethoxy)benzophenone unit in the compound in the formula i.e., the ratio between the methyl methacrylate and the 2-hydroxy 4-(methacryloyloxyethoxy)benzophenone to be copolymerized, there is no special limitation. In the formula, (m) and (n) are integers respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for protecting the surface of an image formed by thermal transfer recording or ink jet recording, and a cover film, an ink ribbon or a coating liquid for ink jet used therefor.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer recording system has been widely used as an image forming method. In recent years, in particular, a sublimation type thermal transfer system for forming a dye image on a photographic paper by using a sublimable or heat diffusible dye. However, since it is possible to form a full-color image with continuous gradation, it has been attracting attention as a method for making a hard copy of a color video image or an image displayed on the screen of a personal computer or the like. However, an image formed by this method has a problem in that it has lower sebum resistance and light fading resistance than silver salt photographs. Therefore, a transparent film is laminated on an image formed by thermal transfer recording in order to protect its surface, prevent photobleaching, and impart sebum resistance.

As a method for laminating a transparent film,
BACKGROUND ART A cover film in which a light-transmissive film such as a polyester film is provided with an adhesive layer is adhered to an image formed on photographic paper. Further, it has been proposed to add an organic ultraviolet absorber to such a cover film to prevent photobleaching of an image.

In addition to the thermal transfer recording method, the ink jet recording method is also widely used as an image forming method. The ink jet recording method forms an image by ejecting liquid ink from a nozzle toward a printing paper by using an electric field, heat, pressure or the like as a driving source. Here, as the dye used in the ink, a water-soluble direct dye or an acid dye is mainly used. Further, for printing paper, a water-soluble polymer having a high affinity for these dyes, an organic or inorganic material is used, and further, an auxiliary substance for controlling dye permeability is used.

In this ink jet recording system, the dye forming the image is held in the dye receiving layer of the photographic paper by Van der Waals force or hydrogen bond as represented by the dye theory of direct dye. Among the dyes used in the inkjet recording system, acid dyes generally have small molecular weight and high water solubility.

Therefore, the image formed by the ink jet recording system has a water resistance problem that the dye flows out when water adheres to the surface of the image. In addition, there is a problem that light fade resistance is low.

Therefore, also for an image formed by the ink jet recording system, a cover film is laminated on the image formed on the photographic paper in the same manner as the protection of the image formed by the thermal transfer recording system. ,
Further, in order to prevent photobleaching, an organic ultraviolet absorber is added to such a cover film.

[0008]

However, when the cover film to be laminated on the image contains an organic ultraviolet absorber for preventing the photo-fading of the image, such an ultraviolet absorber constitutes the cover film. Since the compatibility with the resin component is low, there is a problem that it deposits on the surface of the cover film with the lapse of time and deteriorates the image quality. In addition, when a benzotriazole-based absorber is included among the organic ultraviolet absorbers, the image itself becomes yellowish, so that the image also becomes yellowish, so that there is a problem that the image quality deteriorates.

The present invention is intended to solve the problems of the prior art, and the storability of an image formed by a thermal transfer recording system, an ink jet recording system or the like, in particular, the resistance to photobleaching, is maintained without impairing the image quality. The purpose is to improve.

[0010]

The present inventors have found that the above object can be achieved by using a specific compound as a constituent resin of a cover film, and have completed the present invention.

That is, the present invention provides a compound of the following formula (1) having a methacrylic acid methyl ester unit and a 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit.

[0012]

Embedded image Provided is a method for protecting an image, which comprises forming a transparent film containing (wherein m and n are integers) on the image.

Further, as a cover film which can be used for carrying out the image protection method of the present invention,
Consisting of a base material and a transparent film layer formed thereon,
The transparent film layer provides a cover film containing the compound of formula (1) above.

Further, as an ink ribbon that enables the image protection method of the present invention to be carried out at the time of thermal transfer recording, it has a substrate, an ink layer and a thermal transferable transparent film layer which are separately formed on the same surface thereof. Then, the heat transferable transparent film layer provides an ink ribbon containing the compound of the above formula (1).

Further, as a coating liquid that enables the image protection method of the present invention to be applied to ink jet recording,
Provided is an inkjet coating liquid containing the compound of the above formula (1).

The present invention will be described in detail below.

In the image protection method of the present invention, the compound of formula (1) is used as a constituent compound of a transparent film formed on an image for image protection. The compound of formula (1) is a copolymer of methacrylic acid methyl ester and 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone. Methacrylic acid methyl ester unit and 2-hydroxy 4- in the compound of formula (1)
The ratio of (methacryloyloxyethoxy) benzophenone unit, that is, the ratio of methacrylic acid methyl ester and 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone to be copolymerized is not particularly limited, but the stability and coating property of this compound are not limited. From the above points, the weight ratio is preferably about 3: 7 to 5: 5, and particularly preferably about 5: 5. Further, the molecular weight is preferably about 3.5 × 10 ⁴ .

In the present invention, the resin component of the transparent film formed on the image may be formed only from the compound of formula (1), but if necessary, other compounds compatible with the compound of formula (1) may be used. A resin may be included. For example, a methacrylic acid resin or the like can be contained in order to improve the film forming property. When a resin such as a methacrylic acid resin is included as the resin component of the transparent film in addition to the compound of the formula (1), the formula (1)
It is preferable that the compound of 5% is 5% by weight or more of the resin content of the transparent film. If the proportion of the compound of formula (1) is too low, it becomes difficult to obtain the effects of the present invention.

If necessary, the transparent film may be provided with
Various additives such as UV absorbers, antioxidants, HAL
S (hindered amine light stabilizer), an antistatic agent, etc. can be contained.

The thickness of the transparent film can be appropriately determined according to the application of the image forming the transparent film, the environment in which it is used, etc., but it is generally preferably 5 μm or more, more preferably 5 to 10 μm. preferable.

The method for forming such a transparent film is not particularly limited, and the compound of the formula (1) and other components to be blended if necessary are dissolved in a solvent such as toluene, methyl ethyl ketone, ethyl acetate, and the like. The solution may be applied onto the image by any method and dried. Alternatively, a cover film may be formed in advance by forming a transparent film layer composed of the compound of formula (1) on a substrate, and the transparent film layer of the cover film may be adhered to the image. This transparent film may be formed on the substrate so as to have a thermal transfer property, and the transparent film may be laminated on the formed image when performing thermal transfer recording using the ink ribbon. Further, the solution may be ejected from the ink cartridge of the inkjet recording device by appropriately adjusting the concentration of the solution forming the transparent film. The present invention is a solution of these cover films, ink ribbons, and transparent films prepared for inkjet recording (that is, inkjet coating liquid).
Also includes. These will be described below.

FIG. 1 is a sectional view of the basic embodiment of the cover film of the present invention. The cover film 10 in FIG.
A transparent film layer 2 made of the compound of the above formula (1) is provided on a substrate 1. In the present invention, when such a transparent film layer 2 is adhered to an image to form a protective film for an image, the transparent film 2 layer and the substrate 1 are separated, and only the transparent film layer 2 is adhered to the image. Alternatively, the entire cover film 10 may be adhered to the image without peeling off the transparent film layer 2 and the substrate 1.

Here, the transparent film layer 2 is a formula (which is a copolymer of methyl methacrylate and 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone) as described in the image protection method of the present invention. It is formed using the compound of 1). This copolymer has a weight ratio of the methacrylic acid methyl ester unit to the 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit of 3: 7, as described above.
It is preferably about 5: 5, and more preferably about 5: 5. In addition, the transparent film layer 2 may be formed of the resin component only from the compound of the formula (1), or may be formed from another resin compatible with the compound of the formula (1), if necessary. Further, various additives may be added. Generally, the thickness is preferably 5 μm or more,
More preferably, it is 10 μm.

On the other hand, the base material 1 is not particularly limited and may be transparent or opaque when the transparent film layer 2 is peeled from the base material 1 to serve as an image protective film. For example, a polyester film, a polyimide film or the like having heat resistance can be used.

In this case, a silicone-based release agent, a fluorine-based release agent, a fatty acid ester or the like is used on the transparent film layer side surface of the base material 1 so that the base material 1 and the transparent film layer 2 can be easily peeled off. It is possible to use those that have been subjected to a peeling treatment. A release layer made of an acrylic resin, a silicone resin, a fluorine resin, or the like may be provided between the base material 1 and the transparent film layer 2.

When the entire cover film 10 is adhered to the image without peeling off the transparent film layer 2 and the substrate 1, the substrate 1 is a light-transmissive material so that the image can be seen through. To use. In this case, the degree of light transmission can be appropriately determined and may be semitransparent. As a constituent material of such a light-transmitting substrate, for example, a polyester film such as a polyethylene terephthalate film or a polyethylene naphthalate film, a polyolefin film such as a polyethylene film or a polypropylene film, a polycarbonate film, a polyamide film or the like should be used. You can Among them, heat resistance,
A polyethylene terephthalate film and a polyethylene naphthalate film can be preferably used from the viewpoint of balance of scratch resistance, transparency, cost and the like.

The surface smoothness of the base material 1 is not particularly limited, whether the base material 1 is used by peeling it from the transparent film layer 2 or when it is adhered to an image together with the transparent film layer 2. It may be smooth or mat-like, and may have any pattern.

The thickness of the substrate 1 is also not particularly limited, but it is generally preferable to set it to about 25 to 100 μm.

FIG. 2 is a sectional view of the cover film 11 of the present invention in which the adhesive layer 3 is provided on the transparent film layer 2 of the cover film of FIG. 1 as described above. Thus, the cover film of the present invention can be provided with the adhesive layer 3 in order to improve the adhesion of the transparent film layer 2 to the image. Such an adhesive layer 3 is provided when the transparent film layer 3 is adhered onto the image, when the transparent film layer 2 and the base material 1 are peeled off, and when both are integrally adhered onto the image. be able to.

The adhesive layer 3 can be formed by appropriately using a known adhesive or thermoplastic resin exhibiting adhesiveness under the conditions of thermocompression bonding, such as urethane resin and vinyl chloride-vinyl acetate copolymer. Etc. can be used. The thickness of the adhesive layer 3 can be appropriately determined according to the application of the image to which the transparent film layer 2 is adhered, the type of adhesive, etc., but is generally preferably 10 μm or more.

In addition, an antistatic layer or the like may be laminated on the cover film of the present invention, if necessary.

The cover film of the present invention as described above can be produced by a conventional method. For example, the compound of the formula (1) and optionally other components to be blended are dissolved in a solvent such as toluene or methyl ethyl ketone, and the solution is applied onto a substrate and dried to form a transparent film layer, If necessary, a coating liquid for forming an adhesive layer may be applied to the above and dried.

Next, the ink ribbon of the present invention will be described. FIG. 3 is a sectional view of the basic mode of the ink ribbon of the present invention. The ink ribbon 20 of the same drawing is a thermal transfer recording ink ribbon having an ink layer 22 of each color of yellow Y, magenta M, and cyan C and a heat transferable transparent film layer 23 on the same surface of a substrate 21.

Here, the substrate 21 can be constructed in the same manner as the substrate of the conventional ink ribbon for thermal transfer recording or the substrate 1 of the cover film of the present invention described above.

The heat transferable transparent film layer 23 can be constructed in the same manner as the above-mentioned transparent film layer of the cover film of the present invention, but especially when heat transfer recording is carried out by a printer using this ink ribbon, an image is formed. The transparent film layer 23 has thermal transferability so that the transparent film layer 23 can be easily transferred onto the image by the thermal head of the printer used for the formation. Therefore,
Similar to the case where the base material and the transparent film layer are formed so as to be separable in the cover film of the present invention, the base material 21
It is preferable to perform a peeling treatment on the heat transferable transparent film layer 23 side, or to provide a release layer between the substrate 21 and the heat transferable transparent film layer 23.

The ink layer 22 of each color can be formed for either sublimation type thermal transfer recording or heat melting type thermal transfer recording, if necessary, and each can be constructed in the same manner as a conventional ink layer. For example, when the ink layer for sublimation type thermal transfer recording is used, the ink layer 22 includes a cellulose resin such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetoacetal, poly It may be composed of a vinyl resin such as vinyl acetate or polystyrene, or various urethane resins in which a sublimable or heat diffusible dye is dispersed.

Although FIG. 3 shows an example in which the ink layers of yellow Y, magenta M, and cyan C are sequentially formed as the ink layer 22, an ink layer of black or the like is further formed. Alternatively, an ink layer of only any single color may be formed.

The ink ribbon of the present invention may be provided with various layers other than the substrate, the heat transferable transparent film layer and the ink layer, if necessary. For example, in order to prevent fusion of the ink ribbon and the thermal head at the time of thermal transfer and ensure smooth running property, a heat resistant slipping layer can be provided on the base material opposite to the ink layer. Such a heat resistant slipping layer can be formed from a resin having a high softening point such as cellulose acetate or an epoxy resin, and a lubricant such as silicone oil, wax or fatty acid amide can be coated on the resin layer. Alternatively, it can be formed by adding it in the resin layer or by adding a filler in the resin layer.

Further, when sublimation type thermal transfer recording is carried out, the dye can be transferred from the ink ribbon to the transferred material prior to the transfer of the image so that an image can be formed well even if the dye receiving layer is not formed on the transferred material. Although the receptor layer may be transferred in some cases, a thermal transferable dye receptor layer may be formed on the same side of the ink ribbon as the ink layer in order to transfer the dye receptor layer. Such a dye receiving layer is a polyester resin,
Cellulose ester resin, polycarbonate resin,
It can be formed from a thermoplastic resin having a good dyeing property such as polyvinyl chloride resin.

Next, the inkjet coating liquid of the present invention will be described. This coating liquid consists of the same components as the solution used for forming the transparent film in the above-mentioned image protection method of the present invention, but is used in an inkjet printer by filling this solution into an inkjet ink cartridge. The viscosity of the solution is appropriately adjusted using a solvent such as toluene, methyl ethyl ketone, or diethylene glycol so that it can be obtained. In this case, the viscosity is generally 15 cps (25
C.) or less is preferable.

[0041]

According to the present invention, on the surface of an image formed by thermal transfer recording or ink jet recording, the following formula (1)

[0042]

[Chemical 6] A transparent film composed of the compound is formed. The compound of the formula (1) has an excellent UV absorbing ability based on the 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone unit. Also, this equation (1)
The compound (1) does not precipitate even if it is present in the transparent film layer in a high concentration, and thus can be contained in a high concentration.

Therefore, according to the present invention, it is possible to improve the storability of an image without deteriorating the image quality, and particularly to greatly suppress the photobleaching.

[0044]

EXAMPLES The present invention will be specifically described below based on examples.

Example 1 As a base material, a polyester film whose surface was release-treated with a silicone resin was prepared.

On the other hand, 90 g of methyl ethyl ketone [2-
Hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 5: 5) (UVA-635L, BASF Corporation)
(Made in Japan) 10 g and dissolved, this solution has a dry thickness of 5 μm
Was coated on the release-treated surface of the above-mentioned base material using a bar coater so as to be dried and then a transparent film layer was formed to produce a cover film.

Example 2 As a solution for forming a transparent film layer, 90 g of methyl ethyl ketone was mixed with [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) (UVA- 633
Example 1 was repeated except that 10 g of L and BASF Co., Ltd. was used to produce a cover film.

Further, in a mixed solvent of 40 g of methyl ethyl ketone and 40 g of toluene, cellulose acetate butyrate resin (CAB551.02, manufactured by Kodak) 20
g was added and dissolved, and this solution was applied onto the transparent film layer of the carver film using a bar coater so that the dry thickness was 10 μm, to prepare a cover film with an adhesive layer.

Example 3 As a solution for forming a transparent film layer, 200 g of methyl ethyl ketone was added to 200 g of methyl ethyl ketone, and [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) (UVA- 63
3 L, manufactured by BASF Co., Ltd. 10 g and a methacrylic acid resin (Delpet 560F, manufactured by Asahi Kasei Co., Ltd.) 50 g were dissolved in Example 1 except that a cover film was prepared.

Further, in 80 g of methyl ethyl ketone, a vinyl chloride-vinyl acetate copolymer (Denka vinyl # 1000D, manufactured by Denki Kagaku Kogyo Co., Ltd.) 20 as a thermoplastic resin is added.
g was added and dissolved, and this solution was applied onto the transparent film layer of the carver film using a bar coater so that the dry thickness was 10 μm, to prepare a cover film with an adhesive layer.

Example 4 A cover film was prepared by repeating Example 1 except that a polyester film whose surface was subjected to easy adhesion treatment with a urethane emulsion resin was used as the substrate.

Example 5 A cover film with an adhesive layer was prepared by repeating Example 2 except that a polyester film whose surface was subjected to easy adhesion treatment with a urethane emulsion resin was used as the substrate.

Example 6 A cover film having an adhesive layer was prepared by repeating Example 3 except that a polyester film whose surface was subjected to easy adhesion treatment with a urethane emulsion resin was used as the substrate.

Example 7 A polyethylene terephthalate film (thickness: 6 μm) was prepared as a substrate, and ink layers of yellow, magenta, and cyan colors were formed on the surface sequentially, and a color ribbon VPM manufactured by Sony Corporation was used. An ink ribbon similar to -P100 was produced.

On the other hand, as a solution for forming a transparent film layer, 90 g of methyl ethyl ketone was added to [2] as in Example 1.
-Hydroxy-4- (methacryloyloxyethoxy)
Benzophenone] / methyl methacrylate copolymer (monomer weight ratio 5: 5) (UVA-635L, BASF
(Manufactured by K.K.) 10 g was added and dissolved to prepare a solution, which was applied on the base material of the above ink ribbon so that the dry thickness was 10 μm and dried to form a transparent film layer. 80g of methyl ethyl ketone on the film layer
And cellulose acetate butyrate resin (CAB55
1.02, manufactured by Kodak Co., Ltd.) with a solution of 20 g to a dry thickness of 1
It was applied so as to have a thickness of 0 μm to prepare an ink ribbon having a transparent film layer with an adhesive layer.

Evaluation The following image sample 1 and image sample 2 were prepared as images to which the respective cover films of the examples were adhered.

Image sample 1: Commercially available ink ribbon (VPM-P100ST, manufactured by Sony Corporation), printing paper (VPM-P100ST, manufactured by Sony Corporation), and video printer (CVP-M3, Sony Corporation). Manufactured by the company) and printed a color pattern of each color of yellow (Y), magenta (M), and cyan (C).

Image sample 2: Commercially available ink ribbon (UPC-3010, manufactured by Sony Corporation), printing paper (UPC-3010, manufactured by Sony Corporation), and printer (UP-3000, manufactured by Sony Corporation). ) And are used to print a color pattern of each color of yellow (Y), magenta (M), and cyan (C).

Then, the image screens of the image samples 1 or 2 and the adhesive layer surfaces of the cover films of Examples 1 to 6 were superposed on each other, and a thermocompression laminating apparatus (manufactured by Intercosmos Co., Ltd.) was used. Roller temperature 14
Thermocompression bonding was performed at 0 ° C. and a roller passage speed of 500 mm / min. After allowing to cool to room temperature, the polyester films as the base materials were peeled off from the cover films of Examples 1 to 3.

Further, in order to evaluate the ink ribbon of Example 7, this ink ribbon was used in a video printer (CVP).
-M3, manufactured by Sony Corp.) is used to print a color pattern of each color of yellow (Y), magenta (M), and cyan (C), and the transparent film layer of this ink ribbon is applied to the print screen of each color. Transferred by solid printing on top.

An image fading test was carried out on the image sample in which the transparent film layer was adhered to the printing screen as described above, as follows.

Photobleaching test: 90,000 kJ / using a xenon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.)
Irradiation with energy of m ² is performed. In this case, the optical densities of the yellow (Y), magenta (M), and cyan (C) color portions in the sample are measured before and after irradiation. The residual concentration ratio was calculated.

[0063]

[Equation 1] Further, as Comparative Example 1, the same photobleaching test was conducted without providing a transparent film on the surface of the image sample 1 or the image sample 2.

The results are shown in Table 1.

Comparative Example 2 A methacrylic acid resin (Delpet 560F, manufactured by Asahi Kasei Co., Ltd.) 20 was added to a mixed solvent of 40 g of methyl ethyl ketone and 40 g of toluene as a solution for forming a transparent film layer.
Example 3 was repeated except that a solution obtained by dissolving g was used to produce a cover film with an adhesive layer.

This cover film was adhered to Image Sample 1 and Image Sample 2 in the same manner as above, and a photobleaching test was conducted. Table 1 shows the results.

Comparative Example 3 A solution for forming a transparent film layer was prepared by adding 80 g of methyl ethyl ketone to cellulose acetate butyrate (CAB).
550.02 (manufactured by Kodak Co., Ltd.) was used to dissolve 20 g, and a transparent film layer was formed on the base material of the same ink ribbon as in Example 7 so that the dry thickness was 10 μm, and the transparent film layer was provided. An ink ribbon was produced.

Using this ink ribbon, in the same manner as in the evaluation of the ink ribbon of Example 7, single color patterns of yellow (Y), magenta (M) and cyan (C) were printed, and the printing was performed. The transparent film layer of this ink ribbon was transferred onto the screen, and then a photobleaching test was conducted. Table 1 shows the results.

[0069]

[Table 1] Image sample 1 Image sample 2 Example Base material Transparent film layer Adhesive layer Concentration residual rate (%) Concentration residual rate (%) Y M C Y M C 1 Peeling resin (* 1) -87.2 96.9 80.2 74.3 83.3 92.4 2 Peeling resin (* 2) CAB 86.2 94.2 78.1 71.8 79.7 88.7 3 Peeling resin (* 2), MA Salt-vinegar 82.1 94.1 72.7 70.2 76.0 83.6 4 Adhesive resin (* 1) − 93.4 98.6 90.1 83.7 90.5 96.5 5 Adhesive resin (* 2) CAB 93.4 97.4 85.2 80.2 86.1 92.0 6 Adhesive resin (* 2), MA Salt-vinegar 90.5 95.6 77.6 79.0 84.5 89.8 7 Peeling resin (* 1) Salt-vinegar 97.0 98.8 93.9 Comparative example 1 − − − − 60.3 88.4 55.2 44.1 53.3 61.3 2 Peeling MA Salt-vinegar 63.5 90.2 57.0 46.0 55.5 65.3 3 Peeling CAB − 65.0 90.5 59.0 (Note) (* 1): [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 5: 5) (UVA-635L, B
ASF Corp. (* 2): [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) (UVA-633L, B
MA: Methacrylic acid resin CAB: Cellulose acetate butyrate resin Example 8 As a base material, a polyester film whose surface was release-treated with a silicone resin was prepared.

On the other hand, 90 g of methyl ethyl ketone [2-
Hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 5: 5) (UVA-635L, BASF Corporation)
(Made in Japan) 10 g and dissolved, this solution has a dry thickness of 5 μm
Was applied to the release-treated surface of the substrate by using a bar coater so that it was dried to form a transparent film layer, and a cover film was produced.

Further, ethyl cellulose resin (N-14, HER) was added as a thermoplastic resin to 80 g of ethyl alcohol.
20 g of CULES) was added and dissolved, and this solution was dried on the transparent film layer of the cover film to a dry thickness of 10
The coating film was applied using a bar coater so that the thickness became μm to obtain a cover film with an adhesive layer.

Example 9 As a copolymer for forming a transparent film layer, 90 g of methyl ethyl ketone was mixed with [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) ( UVA-6
Example 8 except that 33L, manufactured by BASF Co., Ltd. is used.
This was repeated to obtain a cover film with an adhesive layer.

Example 10 As a solution for forming a transparent film layer, [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) (UVA-) was added to 200 g of methyl ethyl ketone. 63
3 L, manufactured by BASF Co., Ltd. 10 g and methacrylic acid resin (Delpet 560F, manufactured by Asahi Kasei Co., Ltd.) 50 g were dissolved in Example 8 except that a cover film with an adhesive layer was used. Obtained.

Example 11 Example 8 was repeated except that a polyester film whose surface was subjected to easy adhesion treatment by corona treatment was used as a substrate to obtain a cover film with an adhesive layer.

Example 12 Example 9 was repeated except that a polyester film whose surface was subjected to easy adhesion treatment by corona treatment was used as a substrate to obtain a cover film with an adhesive layer.

Example 13 Example 10 was repeated except that a polyester film whose surface was subjected to easy adhesion treatment by corona treatment was used as the substrate.
This was repeated to obtain a cover film with an adhesive layer.

Evaluation The following image sample 3 and image sample 4 were prepared as images to which the respective cover films of Examples were adhered.

Image sample 3: A single-color color pattern of yellow (Y), magenta (M) and cyan (C) is printed on 1200C dedicated printing paper by using HP DESKJET 1200C as a printer.

Image sample 4: DESKJET 505J manufactured by HP was used as a printer, and yellow (Y), magenta (M), and cyan (C) were printed on a dedicated printing paper for 505J.
A printout of each single color pattern.

Then, the image screens of the image samples 3 or 4 and the adhesive layer surfaces of the cover films of Examples 8 to 13 were superposed on each other, and a thermocompression laminating apparatus (manufactured by Intercosmos Co., Ltd.) was used. And roller temperature 1
Thermocompression bonding was performed at 40 ° C. and a roller passage speed of 500 mm / min. After allowing to cool to room temperature, the polyester films as the base materials of the cover films of Examples 8 to 10 were peeled off and removed.

The image bleaching test was conducted on the image samples 3 and 4 in which the transparent film layer was adhered to the printing screen as described above, and the density residual ratio after irradiation was determined. However, in this case, the irradiation energy is 30,000 kJ / m ²
And

As Comparative Example 4, a similar photobleaching test was conducted without providing a transparent film on the surface of the image sample 3 or the image sample 4.

The results are shown in Table 2.

Example 14 To 99 g of methyl ethyl ketone was added [2-hydroxy-4-
(Methacryloyloxyethoxy) benzophenone] /
Methyl methacrylate copolymer (monomer weight ratio 3: 7)
(UVA-633L, manufactured by BASF Corp.) 1 g was added and dissolved to prepare an inkjet coating liquid. This coating liquid is applied to HP printer DESKJET 120
It was packed in an ink cartridge of 0 C and solid printing was performed on the printing screens of the image sample 3 and the image sample 4 to form a transparent film.

Comparative Example 5 20 g of a methacrylic acid resin (Delpet 560F, manufactured by Asahi Kasei Co., Ltd.) was added to and dissolved in a mixed solvent of 40 g of methyl ethyl ketone and 40 g of toluene to prepare an ink jet coating liquid. This coating liquid was filled in an ink cartridge of a printer DESKJET1200C manufactured by HP, and solid printing was performed on the printing screens of the image sample 3 and the image sample 4 to form a transparent film.

Comparative Example 6 1 g of polyvinyl butyral resin (S-REC BL-S, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 99 g of ethyl alcohol and dissolved to prepare an ink jet coating liquid.
This coating liquid is used for HP printer DESKJET
It was packed in a 1200 C ink cartridge, and solid printing was performed on the printing screens of the image sample 3 and the image sample 4 to form a transparent film.

Evaluation In the same manner as described above, a photobleaching test (irradiation energy of 30000 kJ / m ^{2) was} applied to the image sample 3 or the image sample 4 of Example 14, Comparative Example 5 and Comparative Example 6 on which the transparent film was formed. ) Was carried out to determine the residual concentration ratio after irradiation. Table 2 shows the results.

[0088]

[Table 2] Image sample 3 Image sample 4 Example Base material Transparent film layer Adhesive layer Concentration residual rate (%) Concentration residual rate (%) Y M C Y M C 8 Peeling resin (* 1) CE 90.7 81.5 40.7 92.6 47.2 30.6 9 Peeling resin (* 2) CE 89.5 79.0 38.7 90.0 45.0 28.9 10 Peeling resin (* 2), MA CE 87.9 76.9 36.8 87.7 39.9 22.2 11 Adhesive resin (* 1) CE 94.3 84.1 22.0 97.0 51.4 35.7 12 Adhesive resin (* 2) CE 93.5 82.2 42.1 96.1 50.5 33.0 13 Adhesive resin (* 2), MA CE 89.8 78.5 38.0 93.8 45.1 28.2 14 − Resin (* 2) ) -83.2 69.3 26.1 87.5 38.3 19.0 Comparative example 4 − − − 74.6 57.2 12.0 77.0 24.3 6.5 5 − MA −74.7 58.9 15.3 77.6 25.4 6.9 6 − PVB −75.6 58.1 12.2 78.5 26.0 6.8 (Note) (* 1): [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 5: 5) (UVA-635L, B
ASF Corp. (* 2): [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] / methyl methacrylate copolymer (monomer weight ratio 3: 7) (UVA-633L, B
ASF Co., Ltd.) CE: Ethyl cellulose resin MA: Methacrylic acid resin PVB: Polyvinyl butyral resin From the results of Table 1 and Table 2, when a transparent film is formed on an image according to the present invention,
It can be seen that photobleaching can be largely prevented.

[0089]

According to the present invention, it is possible to greatly improve the storability of an image formed by a thermal transfer recording system, an ink jet recording system or the like, especially the light fading resistance without impairing the image quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cover film of the present invention.

FIG. 2 is a cross-sectional view of a cover film of the present invention.

FIG. 3 is a cross-sectional view of the ink ribbon of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Transparent film layer 3 Adhesive layer 10 Cover film 11 Cover film 20 Ink ribbon 21 Base material 22 Ink layer 23 Thermal transferable transparent film layer

Claims (14)

[Claims] 1. A methacrylic acid methyl ester unit and 2-hydroxy 4- (methacryloyloxyethoxy).
A compound of the following formula (1) having a benzophenone unit: A method for protecting an image, which comprises forming a transparent film containing (wherein, m and n are integers) on the image. 2. The weight ratio of the methacrylic acid methyl ester unit of the formula (1) to the 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone unit is 3: 7.
The image protection method according to claim 1, wherein the image protection method is about 5: 5. 3. The image protecting method according to claim 1, wherein the transparent film containing the compound of formula (1) contains the compound of formula (1) as a resin component and another resin compatible with the compound. 4. A base material and a transparent film layer formed thereon, the transparent film layer having the following formula having a methacrylic acid methyl ester unit and a 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit. Compound of (1) (In the formula, m and n are integers, respectively). 5. The weight ratio of the methacrylic acid methyl ester unit of the formula (1) to the 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit is 3: 7.
The cover film according to claim 4, wherein the cover film has a thickness of about 5: 5. 6. The cover film according to claim 4, wherein the transparent film layer contains, as a resin component, the compound of the formula (1) and another resin compatible with the compound. 7. The cover film according to claim 4, wherein an adhesive layer is formed on the transparent film layer. 8. The cover film according to claim 4, wherein the transparent film layer is formed so as to be peelable from the base material. 9. An ink ribbon having a substrate, an ink layer and a heat transferable transparent film layer separately formed on the same surface of the substrate, wherein the heat transferable transparent film layer comprises a methacrylic acid methyl ester unit and 2- Hydroxy 4-
A compound of the following formula (1) having a (methacryloyloxyethoxy) benzophenone unit: (In the formula, m and n are integers, respectively). 10. The weight ratio of the methacrylic acid methyl ester unit of the formula (1) to the 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit is 3:
The ink ribbon according to claim 9, which is 7 to 5: 5. 11. The ink ribbon according to claim 9, wherein the heat transferable transparent film layer contains, as a resin component, the compound of the formula (1) and another resin compatible with the compound. 12. A compound of the following formula (1) having a methacrylic acid methyl ester unit and a 2-hydroxy 4- (methacryloyloxyethoxy) benzophenone unit: embedded image (In the formula, m and n are integers, respectively). 13. The weight ratio of the methacrylic acid methyl ester unit of the formula (1) to the 2-hydroxy-4- (methacryloyloxyethoxy) benzophenone unit is 3:
The ink ribbon according to claim 12, which is 7 to 5: 5. 14. The inkjet coating liquid according to claim 12, which contains the compound of formula (1) and another resin compatible with the resin as a resin component.